that plant physiology was an area of study that very few women actively pursued
until the 1980s, the Women on Plant Biology Committee would like to acknowledge
those women who were pioneers in studying plants and how they work. Their
research areas are very diverse: genetics, biochemistry, structure, as well
as physiology. Their education, training, and career paths are also diverse.
However, as witnessed by the biographies written by former students, fellow
researchers, admirers, or good friends, each of these women has contributed
to the broad field of plant physiology, and we are grateful to them.
If you would like to
write a biography about someone who you believe should be honored in our
Women in Plant Biology Hall of Fame, please contact Ann Hirsch (firstname.lastname@example.org).
Hildegarde von Bingen
Listen to a musical excerpt from Cum
processit factura, excerpt from Healing
Chants (requires RealPlayer)
Although plant biology now has a considerable number of practitioners who
are women, this was not always the case. Even three-quarters into the twentieth
century, there were few women in research or academic positions who pursued
the study of plant biology. The women featured in this website were pioneers.
By following their heart and their interest in studying plants and plant
processes, they paved the way for many women who followed them. The Women
in Plant Biology Committee is pleased to highlight the careers of these
women so that their contributions to science and to humanity will not be
Our earliest pioneer is Hildegard of Bingen. Hildegard was born in 1098
in Boeckelheim to Hildebert, a nobleman, and his wife Mechthild of Bermersheim.
Hildegard was their tenth child and as was the tradition of the time, Hildegard
was dedicated to the church. At eight years of age, she was sent to study
with Jutta von Spanheim, the sister of Count Meginhard and the Abbess at
a Benedictine convent that had been founded in 675. Jutta taught a number
of young girls in addition to Hildegard, who learned Latin and music, and
read the works of Galen, Dioscorides and other ancient scholars. When Jutta
died, Hildegard, by then a Benedictine nun, replaced her as the Abbess of
the cloister; she was 38 years old at the time. At the age of 50, she founded
a new convent in Rupertsburg near Bingen, and later in her life, she established
another one across the Rhine, on the east bank, in Eibingen. She corresponded
with emperors, kings, bishops, cardinals, and popes, and was well known
in Germany and abroad.
Hildegard was a mystic, subject to visions, which some have suggested
resulted from migraine headaches, and also an illness, which sometimes left
her bedridden. In spite of these difficulties, Hildegard was a prolific
writer of books and music; she was also a painter. In addition, she was
a stalwart supporter of the medieval Church. Parts of her first book, Scivias
(Know the Way of the Lord), were read by Pope Eugene III at the Synod of
Trier in 1147. This established her reputation, and numerous pilgrims came
to the convent to consult with Hildegard. In addition to hymns, paintings,
and books on dogma, Hildegard wrote two books, Physica (Natural
History) and Causae et Cures (Causes and Cures), dealing with plants
and medicine. The original Physica manuscript, which was probably
written in 1150, is lost. What remains are parts of the manuscript dating
from the 13th to the 15th centuries, and a printed version dating from 1533.
Hildegard died in 1179 at the age of 81, and although almost a millennium
has gone by, her works, especially her music, are still known today.
Hildegard's contribution to plant biology was as an herbalist. In her
time, plants were primarily written about in terms of their impact on human
health. The herbalists usually copied the works of Dioscorides and Theophrastus,
producing handwritten manuscripts that were lavishly illustrated. Hildegard
took another approach. Her books are not merely copies of previous texts;
rather they are Hildegard's own reflections on plants and their medical
uses, based in part on the Bible and knowledge of the past, but also on
local wisdom. Many monasteries and convents in the Medieval Europe were
the repositories of medical knowledge for much of the local population.
Some of Hildegard's recommendations, such as using Psyllium for
"fevers in [the] stomach", or hemp, which-"if one is weak in the head, and
has a vacant brain, eats hemp, it easily afflicts his brain. It does not
harm one who has a healthy head and full brain"-have validity today. Although
her approach to medicine recognized that plants could help remedy certain
ills, she was also very sanguine about the efficacy of some of the suggested
cures. She wrote in Causae et Cures: "These remedies come from
God and will either heal people or they must die, or God does not wish them
to be healed".
In Isley's book, One Hundred and One Botanists, one of the references
used in preparation of this biography, Hildegard of Bingen is one of only
four women who are profiled. There must have been many others since Hildegard's
time and now, no doubt numerous unsung heroines, either working behind the
scenes or neglected by history. Our goal in this website is to bring women
pioneers in plant biology out of the shadows and into the light.
Ann M. Hirsch, University of California-Los Angeles
Isley, D. 1994. One Hundred and One Botanists. Iowa State University
Press. Ames, IA.
Strehlow, W. and Hertzka, G. 1988. Hildegard of Bingen's Medicine.
Bear & Company, Santa Fe, NM.
Throop, P. 1998. Hildegard von Bingen's Physica. The Complete English
Translation of Her Classic Work on Health and Healing. Healing Arts Press,
B. CREIGHTON (1909-2004)
Harriet Creighton (1909-2004)
was the third woman elected to the presidency (1956) and the first woman
secretary (1950-54) of the Botanical Society of America (BSA). Creighton's
many contributions to the BSA and to botanical education are often overshadowed
by her most cited work, the first demonstration of cytological and genetical
crossing-over in Zea mays. The investigation was part of Creighton's
dissertation research project at Cornell University (1929-1934), under the
guidance of her collaborator, Dr. Barbara McClintock, who had suggested
the problem. Their study provided additional confirmation of the chromosome
theory of inheritance for which Thomas Hunt Morgan would win a Nobel Prize
and early contributions to maize genetics may be found in issues of Proceedings
of the National Academy of Sciences (PNAS), Maize Genetics Cooperation News
Letter, Records of the Genetics Society of America, and citations to
her works appear in many books and journals, whose authors also acknowledge
her for sharing data. Her major contributions to our field, however, are
her behind-the-scenes participation on many national science education committees
for the BSA, the American Institute of Biological Sciences (AIBS), and the
National Science Foundation's National Research Council (NSF/NRC). Much
of her involvement on these committees has been described in the pages of
the Plant Science Bulletin (PSB), of which she was a founding member
and editor by 1958. She wrote articles encouraging innovation in teaching,
and in her retiring presidential address, she encouraged her fellow botanists
to be as proud as she was of their botanical roots, and challenged them
with the call "Botanists of the World, Unite! and Get Going."
The Cornell Years:
Creighton was born in Delavan, Illinois on June 29, 1909. At age 20 she
graduated from Wellesley College (A.B. 1929), and accepted an assistantship
(1929-1932) in General Botany in the Department of Botany, College of Agriculture,
at Cornell University. There, Dr. Barbara McClintock suggested that she
pursue a Doctorate in Cytology with Professor Lester W. Sharp. McClintock
also suggested Creighton's minor subject areas, Plant Physiology and Genetics.
In 1929, Creighton learned many new plant cytological techniques from McClintock,
who years later would win the Nobel Prize for her discovery of transposable
elements in corn.
By 1931, Creighton and
McClintock used a semisterile corn stock with a prominent knob at the tip
of the short arm of chromosome 9, and having a piece of chromosome 8 attached
(a translocation) for their study of a correlation of "genetical and
cytological crossing over," published in the August 1931, PNAS. At
the 6th International Congress of Genetics, held at Cornell in 1932, Creighton
and McClintock collaboratively presented evidence for 4-strand crossing
over in corn. Creighton continued to contribute unpublished data to the
Maize Genetics Cooperation News Letter, and published new findings
on deficiencies on chromosome 9 of corn.
As a graduate student,
Creighton was elected to the Women's Scientific Fraternity, Sigma Delta
Epsilon (Graduate Women in Science) in 1930 (established at Cornell
in 1921) and she later became an officer of the National organization. In
1931, she was elected to the Cornell Chapter of the honorary scientific
society, Sigma Xi, and to Phi Kappa Phi, in 1932. Creighton
completed her doctorate in 1933 and remained in the Botany Department at
Cornell as an Instructor of cytology and microtechnique (1932-1934), until
accepting a job at Connecticut College for Women (CCW) in 1934.
for women, 1934-1940: Creighton was an Instructor in Botany at CCW
(1934-1938) and was promoted to Assistant Professor in 1938. In 1935, with
McClintock, she published a corroboration of their investigations of cytological
crossing over. Creighton worked collaboratively with G.S. Avery, P.R. Burkholder,
and others at Connecticut College, on a translation and revision of Peter
Boysen-Jensen's (1883-1959) Growth Hormones in Plants, which was
expanded to include 188 new contributions to the literature and 40 additional
illustrations. With Avery, Burkholder, and others at Connecticut College,
she also conducted a series of plant physiology experiments that were mainly
published in the American Journal of Botany (AJB) between 1936 and
In 1940, Creighton was
appointed Associate Professor of Botany at Wellesley College, and was elected
a Fellow of the AAAS. In addition to teaching, she continued to conduct
research on corn. Soon after the U.S. entered World War II, Creighton was
granted a leave of absence for war service (1943-May 1946) and rose to the
final rank of Lieutenant Commander in the WAVES.
Upon returning to Wellesley,
she was appointed Chair of her Department. She enthusiastically supported
Wellesley's Arboretum, Botanic Gardens and The Margaret C. Ferguson Greenhouses
as "premier educational sites" and was committed to maintaining
them as such. In 1946, she initiated Garden Day, where local garden clubs
were invited to Wellesley to view the greenhouse and gardens. This eventually
led to the founding of the Wellesley College Friends of Horticulture (WCFH)
in 1982, whose members raised funds for the renovation of the Ferguson Greenhouses,
completed ten years later. The Harriet B. Creighton Room at the Visitor
Center of the Margaret C. Ferguson Greenhouses was dedicated to honor her
years of service to the Botany Department and her ongoing support for the
College's Botanic Gardens.
Creighton served as
Secretary of the BSA Teaching Section (1948-1951), was a member of the AAAS
Council (1949-1951), and was elected Secretary of the BSA in 1950. She was
promoted to Professor of Botany in 1952 and that year she was a Fulbright
Lecturer at the University of Western Australia, Perth, and at Adelaide
University. Seven years later, she again was a Fulbright Lecturer at the
National University of Cuzco, Peru.
In 1955, Creighton was
named the Ruby F.H. Farwell Professor of Botany at Wellesley. In that year,
she was also elected Vice-president of the BSA, served on the PSB
editorial board (through 1959) and participated (through 1958) in an NSF
Panel for the selection of Predoctoral Fellows. She also served as a Member-at
Large for the 14th -16th (1955-1957) Symposium of the Society for Developmental
commitment to Botanical Education: As a member of the Botanical
Society's Education Committee, Creighton supported their proposal to the
National Science Foundation (NSF) for a Summer Institute for Botany teachers
from small colleges to be held at Cornell in 1956. Creighton served on NSF
Panels for Summer Institutes for College and High School Teachers of Biology
through 1959. She was one of the outstanding lecturers who participated
in the NSF-supported Summer Institute for College Botany Teachers, sponsored
by the BSA, in 1959. Concurrently, she was a member of the NSF Committee
on Teaching Biology (1956-1957), and was invited to join the AIBS Committee
on Education and Professional Recruitment's Steering Committee (1956-1966)
for the Secondary School Film Series in which she played a "teacher"
in several individual films. While editor of PSB, Creighton (1958) encouraged
writers and publishers of Botany and Biology text books to "experiment
with texts that are really a third arm of a course, the first two being
the teacher and the organisms studied in the field and laboratory."
Creighton was secretary
(1960-1963) of Section G (Botanical Sciences) of the AAAS, and concurrently
chaired the BSA's Committee on Education for two years (1960-1962). The
Committee studied the Role of Botany in America, and she helped to formulate
their recommendations concerning High School Biology Courses, and Introductory
Courses in Biology. As part of her responsibilities for this committee,
Creighton was a botanical consultant (1961-1969) to A. J. Nystrom and Co.
(Chicago), who produced teaching charts and models of plant structure, which
she had designed.
and further responsibilities: Creighton pursued research on the
genetics of Petunia flowers, which she presented independently, and with
students, at the annual meetings of the Genetics Society of America (GSA)
in the 1940s. Later, she became interested in the horticultural aspects
of Begonia. Those studies were presented at the BSA, and published in The
Begonian during the 1960 and 1970s. She spent a sabbatical year in the
Botany Department at the University of California, Berkeley (1966) and at
the Cell Research Institute of the University of Texas in Austin (1967).
In the early 1960s,
she was President of the Wellesley Chapter of the Society of Sigma Xi. She
traveled to India as a consultant for NSF (1968, 1969) and also accepted
committee assignments from the GSA. Creighton was an editorial board member
(1969-1975) of the Journal of College Science Teaching, representative
to the Executive Committee from the Historical Section of the BSA (1973)
and in addition, refereed book manuscripts, journal articles, and published
many book reviews. She taught a class on Basic Botany and Horticulture for
the Massachusetts Horticultural Society, and gave a National Science Teachers
Association workshop for high school teachers on the use of plants for experiments
in their classes.
The Retirement Years
1974-2004, and beyond
Honors and Recognition:
Creighton kept busy after her 1974 retirement as Ruby F.H. Farwell Professor
Emerita. She was consulted on all aspects of Wellesley College life and
wrote the chapter on "The Grounds" for the centennial volume Wellesley
College 1875-1975, A Century of Women. The Massachusetts Horticultural
Society honored her with the Large Gold Medal of their society in 1985,
for her botanical expertise and "horticultural concern in the community."
In 1994, The Wellesley College Alumnae Association recognized her with the
Syrina Stackpole Award for "dedicated service and exceptional commitment
to Wellesley College."
Creighton died at age 94, on January 9, 2004. That year, the Wellesley
College Botanical Greenhouse Fund, established by Creighton in 1955 with
an initial modest gift, was renamed the Harriet Creighton Greenhouse Fund
for continued support of the Margaret Clay Ferguson Greenhouses.
Creighton lived a long,
happy, and successful life. Her legacy of contributions to Botany in the
20th century has persisted and sustained the broad field of Plant Biology.
-- by Lee B. Kass, Visiting
Professor, Cornell University, excerpted from:
Kass, L. B. 2005. Harriet Creighton: Proud Botanist. Plant Science Bulletin
Harriet Creighton outside
the Margaret C. Ferguson Greenhouses, Wellesley College, 1994 (Photograph
by Lee Kass).
Johanna Döbereiner (1924 - 2000)
Johanna Döbereiner was a remarkable woman, a true pioneer in the study of plant-microbe interactions. Her early life was not easy. Born November 28, 1924 in the former Czechoslovakia, her family was forced to immigrate to Germany at the end of the World War II. After completing her graduate work at the University of Munich, she moved to Brazil in 1951 and became a Brazilian citizen in 1956. She joined the Research Department of the Brazilian Ministry of Agriculture (currently known as Embrapa) in the 1950’s where her career lasted for almost 50 years. Here, she started her research on what is now known as associative nitrogen fixation. When she began, little attention was given to the possibility that nitrogen-fixing bacteria were associated with non-legume crops, particularly the cereal grasses, and furthermore, that these bacteria could promote plant growth by providing fixed nitrogen. In her early work, Johanna found a number of bacteria in Brazilian soils, including Azotobacter (later named Azorhizophilus) paspali and Beijerinckia fluminense, in soils surrounding cereal grasses; B. fluminense was also found in the rhizoplane of sugarcane. She also studied a number of Brazilian species of Azospirillum, the only bacterial genus other than the rhizobia used as inoculants for crops.
Two critical events in the 1970’s enabled Johanna to advance her research further. One was the petrleum crisis of the early 1970’s, which caused the price of chemical fertilizer to increase significantly, and the other was the development of the acetylene reduction assay (ARA), a relatively easy detection system for determining low levels of nitrogenase, i.e. biological nitrogen fixation (BNF), activity. Many Brazilian pasture grasses tested positive for nitrogenase activity using ARA and a semi-solid medium developed by Johanna and her students, strongly suggesting the presence of an associated nitrogen-fixing bacterial species. In the 1980’s, Johanna and her colleagues found a number of nitrogen-fixing bacteria that colonized the inner tissues of plants (endophytes, a term coined by Johanna). Herbaspirillum seropedicae was isolated from maize, sorghum, and rice, whereas Gluconoacetobacteria diazotrophicus was isolated from sugarcane. Indeed, various sugarcane varieties were found to obtain 30 to 50% of their nitrogen from BNF via endophytic bacteria although no single genus has been identified as the source of fixed nitrogen. Nevertheless, associative nitrogen fixation was firmly established as a means of providing fixed nitrogen to plants. Currently, 5 million hectares of Brazilian farmland is planted in sugarcane, and more than half of the cane is processed into 13 billion liters per year of bioethanol, which fuels 10-12 million cars.
However, Johanna did not envision “microbe hunting” as her ultimate goal. She and her colleagues noted different responses of maize and other cereal grain cultivars to the endophytes and thus advocated breeding programs to capitalize on the genetic diversity inherent in the plants. She insisted on breeding high-yielding soybeans on nitrogen-deficient soil so they that were completely dependent on BNF. The net result was that such a strategy reduced Brazil’s dependence on chemical fertilizer, thus saving billions of dollars annually. It also led to Brazil becoming the second largest grower of soybean in the world after the U.S. and made the nation a dominant force in the agricultural marketplace.
For her contributions to Brazilian agriculture, Johanna was the recipient of many awards during her lifetime, including membership in the Brazilian Academy of Science and the Vatican Pontifical Academy of Sciences (there are only 75 members throughout the world). She was a founding member of the Third World Academy of Sciences and also a member of the New York Academy of Sciences. She was honored with the title Doctor “Honoris Causa” from the University of Florida and the Federal Rural University of Rio de Janeiro. She was the recipient of more than 12 national and international prizes and also received many other international honors, such as the Bernardo A. Houssay Science Prize from the Organization of American States. One of her students noted in the obituary he wrote that Johanna was the most cited Brazilian female scientist and the seventh most cited Brazilian by the international community. Her scientific output was large not only in research papers and presentations at meetings, but also in the number of students and trainees that she mentored. She was the subject of numerous magazine and newspaper articles in Brazil, especially after the news leaked out that she had been nominated for the Nobel Prize in Chemistry in 1997. Although she did not win this prize, she already had won the respect and admiration of many, especially her students and colleagues in the nitrogen fixation field.
Johanna Döbereiner passed away on October 5, 2000.
Baldani, J.I., and Bandani, V.L.D. 2005. History on the biological nitrogen fixation research in gramineous plants: special emphasis on the Brazilian experience. Ann. Brazil. Acad. Sci. 77: 549-579.
Baldani, J.I., Bandani, V.L.D., and Reis, V.M. 2002. Johanna Döbereiner: fifty years educated to the biological nitrogen fixation research area. In: Nitrogen Fixation: Global Perspectives. Eds. T. Finan, M. O’Brian, D. Layzell, K. Vessey, and W. Newton. CABI Publishing, N.Y., N.Y. Pp. 3-4.
Boddey, R.M., Urquiaga, S., Alves, B.J.R. and Reis, V. 2003. Endophytic nitrogen fixation in sugarcane: present knowledge and future applications. Plant Soil. 252: 139-149.
Franco, A.A., and Boddey, R.M. 1997. Dr. Johanna Döbereiner: a brief biography. Soil Biol. Biochem. 29: ix-xi.
Photograph by Robert M. Boddey
Esau, Ph.D., N.A.S.
"Dedicated to the brilliant scholar Professor Emeritus Katherine
Esau. An illuminating teacher, classic textbook author, and historical monographer;
A critical researcher and lucid explicator on plant viruses, developmental
and pathologic plant anatomy, and on ultrastructure of phloem, for whom
these facilities were designed when she came to this campus from UC-Davis
This dedication, written by her close colleague and friend, Vernon I.
Cheadle, appears on the plaque designating the research building that served
as the laboratory and electron microscope facility of Dr. Katherine Esau
on the University of California-Santa Barbara campus.
Katherine was born on April 3, 1898, in the city of Yekaterinoslav, now
called Dnepropetrovsk, in the Ukraine. She lived there until the end of
1918, when she and her family fled to Germany during the Bolshevik Revolution.
When the Esau family fled Russia, Katherine had just completed her first
year of study at the Golitsin Women's Agricultural College in Moscow. Upon
arriving in Germany, Katherine enrolled in the Agricultural College of Berlin.
She spent three years at the college and developed a close acquaintance
with Professor Erwin Baur, a geneticist who became famous for his studies
in plant breeding.
In 1922, the Esaus left Germany for the United States, where they settled
in Reedly, California, a strong Mennonite community. In 1923, Katherine
took a job with the Sloan Seed Company in Oxnard, California. One year later,
she was hired at the Spreckels Sugar Company in Salinas, California, to
develop a sugarbeet resistant to curly-top disease, a virus that was a major
problem to growers in that state. In 1928, Katherine left Spreckels to begin
her graduate studies at the University of California-Berkeley. This marked
the beginning of her exceptional and productive 64-year career in plant
Katherine graduated from Berkeley in 1932 and was employed at UC-Davis
as an instructor and junior botanist. Throughout her career, she studied
phloem, the food conducting tissue in plants, both in relation to the effects
of the phloem-limited viruses upon plant structure and development and to
the unique structure of the sieve tubes, food conducting cells. Katherine
had an exceptional ability for attacking basic problems, and she set new
standards of excellence for the investigation of anatomical problems in
the plant sciences.
During her tenure at UC-Davis, Katherine received many honors and distinctions,
including a Certificate of Merit on the Golden Jubilee Anniversary of the
Botanical Society of America in 1956; election to the National Academy of
Sciences in 1957; and an honorary degree from Mills College, Oakland, in
1962. She also served as President of the Botanical Society of America in
In 1963, Katherine moved to Santa Barbara to continue her collaboration
with Dr. Vernon I. Cheadle, who had been appointed Chancellor of that UC
campus. They had been research colleagues at UC-Davis for 10 years studying
the comparative structure of the food conducting tissue in higher plants.
She considered her years in Santa Barbara to be her most productive and
fulfilling. She had been introduced to electron microscopy just before leaving
Davis, and she was interested in applying this new tool to her anatomical
research. An electron microscope, the first on the Santa Barbara campus,
was purchased and installed soon after her arrival. Although Katherine retired
in 1965, she remained actively engaged in research for 24 more years.
In 1989, Katherine was awarded the President's National Medal of Science
by George H. Bush. The citation accompanying the medal reads: "In recognition
of her distinguished service to the American community of plant biologists,
and for the excellence of her pioneering research, both basic and applied,
on plant structure and development, which has spanned more that six decades;
for her superlative performance as an educator, in the classroom and through
her books; for the encouragement and inspiration she has given to a legion
of young, aspiring plant biologists; and for providing a special role model
for women in science."
Katherine was especially well known for her beautifully written and comprehensive
textbooks. Her first book, Plant Anatomy, was published in 1953,
and it became a classic almost immediately. The book was and still is fondly
called the "bible" for structural botanists. Her developmental approach
and thorough presentation of the structure and development of a wide variety
of economically important plants resulted in a book that revitalized plant
anatomy throughout the world. In 1961, Anatomy of Seed Plants,
was published for less comprehensive courses. These books provided a standardized
and unified terminology for plant anatomy. Between 1965 and 1977, she revised
her Plant Anatomy book and Anatomy of Seed Plants and
wrote three additional books: Vascular Differentiation in Plants;
Viruses in Plant Hosts: Form, Distribution, and Pathologic Effects;
and The Phloem. The Phloem covers the structure and development
of the phloem, beginning with the earliest records of this tissue. It is
one of her greatest contributions.
Katherine was a superb teacher, serving as major professor for 15 doctoral
students. She gave freely of her time and was always available to provide
advice, encouragement, and praise. I was fortunate to be her last graduate
student, joining her laboratory in 1979, when she was 81 years old. Our
relationship as mentor and student transformed to colleague and friend,
and ultimately my role became one of providing care and assistance during
the last several years of her life.
Jennifer Thorsch, University of California Santa Barbara
Enid MacRobbie, ScD, FRS, FRSE
Throughout her career, Enid MacRobbie has been at the forefront of studies
of ion transport in plants, addressing fundamental questions in plant nutrition
and cell signalling. She pioneered the use of radiotracers to measure ion
fluxes, identified active and passive transport processes and their regulation
in giant algae, and unravelled the transport events involved in stomatal
movement in higher plants. She has trained a succession of outstanding Ph.D.
students, who have gone on to become influential scientists in their own
right, and has won worldwide recognition and honors for her research. There
is no doubt that her career has helped change conditions for women scientists,
to the benefit of those who have followed.
Enid was born in Edinburgh, Scotland in 1931 and attended high school
and university in that city. She studied physics for her B.Sc. degree and
was awarded a 1st class honors in 1953. She stayed at the University of
Edinburgh for her Ph.D. becoming the first graduate student in Jack Dainty's
new biophysics research group. The group was part of the Department of Physics,
but, characteristically in those post-war years, was accommodated in a converted
chicken house behind the Department of Genetics. In her Ph.D. project, Enid
made the first use of radioisotopes to measure ion fluxes in plants. Her
initial work was with the seaweeds Rhodymenia palmata and Ulva
lactuca, but she subsequently moved to the conceptually simpler system
of the giant internode cells of the alga Nitellopsis obtusa. Her
thesis work established the theoretical framework for, and practical application
of, isotope efflux analysis-a technique that had been developed in animal
cells, but which was made more complicated in plants because of the presence
of the large central vacuole. The resulting papers were pioneering and immediately
established Enid's reputation in her chosen field.
At the end of her Ph.D. research in 1957, Enid moved to a postdoctoral
position with Professor H. H. Ussing at the Institute of Biological Isotope
Research in Copenhagen where she studied ion transport in frog skin. After
one year there, she secured a Research Fellowship at Girton College in Cambridge
and moved back to the United Kingdom. Enid's initial hope had been to work
with Nobel Laureate Alan Hodgkin in the Department of Physiology but, given
her interests, he suggested that it might be better if she joined George
Briggs, Professor of Botany, who was interested in the ionic relations of
plant cells. Thus began her association with the Botany School (now Department
of Plant Sciences) in the University of Cambridge where she has been an
inspirational colleague for more than 40 years. Briggs gave Enid freedom
to follow her instincts, and she began using isotopes to measure fluxes
of K+, Na+ and Cl- in the giant alga Nitella
translucens. Her main aim was to establish which fluxes at the plasma
membrane and tonoplast were active and which were passive, and how they
were regulated, information that was essential to establish the molecular
mechanisms of ion movement in plants. The work was outstandingly successful.
It secured her international reputation and helped establish a more quantitative
and biophysical approach to studies of plant transport systems.
Professor Briggs retired in 1960 and teaching quantitative plant physiology
was taken over by Enid, Michael Pitman, and Martin Canny. When, in 1962,
Michael Pitman left Cambridge for the University of Adelaide, Enid was recruited
to the Demonstratorship (Cambridge's equivalent of a non-tenured Assistant
Professorship) he vacated. Her research was given a major boost when, in
1964, she, Jack Dainty (by then the inaugural Professor of Biophysics at
the newly-opened University of East Anglia), and Charles Whittingham (at
Imperial College, London) were awarded a substantial 5-year grant by the
Nuffield Foundation. This allowed Enid to build a group quickly and to establish
strong links with the Dainty group in Norwich. The latter brought the additional
benefit of contacts with a number of talented Australian biophysicists,
including Alex Hope, Alan Walker and Geoff Findlay, who became life-long
scientific friends and collaborators. The Nuffield grant was doubly useful
because it came with no strings attached, and Enid could spend with complete
flexibility, a sharp contrast with the limitations placed on modern grants
in these days of accountability! This period also saw the start of Enid's
role as an inspirational Ph.D. supervisor when F. Andrew Smith joined her
in 1962 as her first Ph.D. student. A year later, John Raven and John Cram
were recruited, and the group quickly grew to ten, including Roger Spanswick,
who was a postdoctoral associate.
From 1962 to the mid-1970s, the group was concerned mainly with characterizing
ion fluxes at the plasma membrane and tonoplast of giant algae, but in 1978,
Enid made a major change in research direction when she decided to begin
studying the mechanism of stomatal guard cell movement, the fundamental
process by which plants regulate the uptake of gases and the loss of water.
The switch to stomates was driven by the realization that the nature of
the fluxes underlying changes in ion content during opening and closing
were largely unknown. Enid began studying this problem using her established
methods, but adapting them to the more challenging guard cell system. She
received her first grant for this work in the early 1980s and it has remained
the mainstay of her research since then. As with her work on giant algae,
Enid has made an important contribution to our understanding of the control
of stomatal closure and her research has provided important quantitative
flux information that complements studies done by other means, such as patch
Enid's laboratory has been the incubator for the fledgling career of many
now-distinguished plant physiologists. These include F. Andrew Smith, John
Raven, John Cram, Roger Spanswick, Mel Tyree, Richard Williamson, Dale Sanders,
Roger Leigh, Carol Shennan, Mike Blatt, Mark Tester, Mary Beilby, and Gerhardt
Thiel, to name just a few. Enid's input to the work of her colleagues is
always constructive. She is able to identify and focus on the key issues,
and through this, draw the best out of others. Her positive outlook on the
work of her colleagues remains the abiding memory of many of her former
students and postdocs. As one former postdoc put it: "Some of my fondest
memories of my time in Cambridge are of sitting with Enid talking through
data or ideas and coming away knowing that I've been 'stretched' and have
enjoyed the experience."
An unusual feature of Enid's approach is that she has actively encouraged
the majority of the people who have worked with her to publish papers without
her name on them. Thus only about 25% of the papers published by her colleagues
during their time in her lab have included her as a co-author. Therefore,
any literature search using her name as key words will substantially underestimate
the full extent of the output of her laboratory. This has been a remarkably
selfless approach to science that has given added impetus to the careers
of those whom she has mentored. It is unlikely that, in these days of citation
analyses, present or future scientists will feel willing or able to make
such a magnanimous gesture. As a result of her unselfish approach, it can
be guaranteed that the papers with Enid's name on them indicate that she
made a real and important practical contribution to the work. Throughout
her career, she has always conducted her own experiments and all her free
time is spent at the bench. Even now, following her official retirement
in 1999, and at the start of her eighth decade, she remains active and can
daily be seen performing flux measurements, reviewing papers, or offering
advice to younger colleagues who regularly seek her counsel.
Enid's influence extends well beyond her own research laboratory. In her
role as a teacher, she has influenced generations of Cambridge undergraduates
to consider a career in research. Together with the late Tom ap Rees, she
revolutionized the content of botanical courses in Cambridge in the 1960s
and 1970s by introducing more cell biology and biochemistry, and emphasising
quantitative approaches and analytical thinking. She was particularly effective
in the small-group tutorial teaching that is a special part of teaching
in Cambridge, and it is not uncommon to meet former undergraduates for whom
Enid's teaching has been a life-long inspiration. Girton College, where
she has been a Fellow since 1958, was the first women's college in Cambridge
and has an outstanding record of promoting equal opportunities for women
in higher education. In her role as a teacher at the College, Enid influenced
many women undergraduates to pursue science as a career and many of them
have gone on to gain international recognition.
Enid's career has resulted in many honors and measures of esteem, although
often these came scandalously late considering the influence she has had
on her field, possibly because she was a woman in a male-dominated environment
and because of her policy of letting students and postdocs publish without
her. She was appointed to a permanent Lectureship in 1966, was promoted
to a Readership in 1972, and to a Personal Professorship in 1987, the first
woman scientist in Cambridge to be awarded a Personal Chair. A year later,
she was awarded a Doctor of Science (Sc.D.) by the University. She was elected
a Fellow of the Royal Society of London (the highest honor in U.K science)
in 1991, is a Fellow of the Royal Society of Edinburgh (elected 1998), and
a Foreign Member of the National Academy of Sciences of the USA (since 1999).
She is also a Corresponding Member of the American Society of Plant Biologists.
Her 40 years of service to Girton College were recognized by her election
to a Life Fellowship in 1999. In her spare time, which even in retirement
is not abundant, Enid amuses herself with gardening, walking, and trout
fishing. The latter is mainly done when she escapes to her holiday house
in Kilchoan on the Ardnamurchan Peninsula, the most westerly point on mainland
Throughout her career, Enid MacRobbie has sought to make biologists think
quantitatively. Often she has had an uphill struggle because most consider
themselves mathematically inept and unable to use equations. Enid's aim
has been to show them that they can, and that their scientific understanding
is enhanced as a result. Her own work more than adequately demonstrates
how a quantitative approach can enlighten, and her outstanding achievements
as a scientist, teacher, and unselfish individual will have influence on
plant physiology for many years. Her legacy will be both an outstanding
research record and a cohort of talented individuals who have gone on to
make their own mark on plant biology.
Roger A. Leigh, Department of Plant Sciences, University of Cambridge
Distinguished University Professor
University of Massachusetts Amherst
Lynn Margulis is Distinguished
University Professor in the Department of Geosciences at the University
of Massachusetts, Amherst. Her publications, spanning a wide range of scientific
topics, include original contributions to cell biology and microbial evolution.
She is best known for her theory of symbiogenesis, which challenges a central
tenet of neodarwinism. She argues that inherited variation, significant
in evolution, does not come mainly from random mutations. Rather, new tissues,
organs, and even new species evolve primarily through the long-lasting intimacy
of strangers. The fusion of genomes in symbioses followed by natural selection,
she suggests, leads to increasingly complex levels of individuality. Dr.
Margulis is also acknowledged for her contribution to James E. Lovelock's
Gaia concept. Gaia theory posits that, on the Earth, surface interactions
among living beings, sediment, air, and water have created a vast self-regulating
Professor Margulis helps
develop hands-on science teaching activities at levels from middle to graduate
school, including Introduction to the Carbon Cycle: What happens to
trash and garbage?; Living Sands, Using Forams to Map Time and Space and
Peas and Particles: Estimating Large Numbers to Understand Natural Selection.
She has made many short videos of live organisms for advanced students and
researchers; the most recents ones are Eukaryosis: Origin of Nucleated
Cells and Forbidden Fertilization. She is the author of many articles
and books. The most recent include Symbiotic Planet: A new look at
evolution (1998) and Acquiring Genomes: A theory of the origins
of species (2002), co-written with Dorion Sagan. Indeed, over the
past decade and a half, Professor Margulis has co-written a number of books
with Sagan, among them What is Sex? (1997); What is
Life? (1995); Mystery Dance: On the evolution of human sexuality
(1991); Microcosmos: Four billion years of evolution from our microbial
ancestors (1986); and Origins of Sex: Three billion years
of genetic recombination (1986). Her work with K. V. Schwartz provides
a consistent formal classification of all life on Earth and has led to the
third edition of Five Kingdoms: An illustrated guide to the phyla
of life on Earth (1998). Their evolutionary classification scheme
was generated from the scientific results of numerous colleagues. The logical
basis for it is summarized in her single-authored book Symbiosis in
Cell Evolution: Microbial communities in the Archean and Proterozoic eons
(second edition, 1993). The bacterial origins of both chloroplasts
and mitochondria are established. At present, with colleagues and graduate
students, she explores the possible origin of cilia from spirochetes. Experiments
and observations involve studies of free-living mud spirochetes, sequence
comparisons of eukaryotic motility proteins with those of spirochetes and
other prokaryotes, and cytological studies with termite archaeprotists (amitochondriates
under anoxic conditions such as the devescovinids and calonymphids).
Environmental Evolution, a course on the effects of life on the evolution
of the Earth's surface, primarily to seniors and graduate students, although
science teachers tend to take the course in the summer. This course itself
evolves. She often has taught it with her PhD students. MIT Press has published
a second edition of the text for the course, which has been taught every
semester since it was begun at Boston University in 1972.
Dr. Margulis received
her AB degree in liberal arts from the University of Chicago, her Master's
degree in Zoology and Genetics at the University of Wisconsin-Madison and
her PhD in genetics at the University of California , Berkeley. She was
elected to the National Academy of Sciences in 1983 and received the Presidential
Medal of Science from President William J. Clinton in 1999. She was a recipient
of an Alexander von Humboldt prize from Germany in 2002. The Library of
Congress announced in 1998 that it will permanently archive her papers.
Prior to her move to the Botany Department at the University of Massachusetts,
she was a faculty member at Boston University for 22 years.
Barbara McClintock (1902-1992),
one of the foremost women scientists in 20th century America, is most noted
for her pioneering research on transposable elements in maize. For this
work, she was awarded the Nobel Prize in Physiology or Medicine in 1983.
She was the third woman to receive an unshared Nobel Prize in the sciences.
Born in Hartford, Connecticut,
on June 16, 1902, Barbara McClintock was raised in Brooklyn, New York. After
graduating from Erasmus Hall high school, she entered Cornell University
at age 17, and in 1923 earned a B.S. in agriculture, concentrating in plant
breeding and botany. She received both her masters (1925) and doctoral degrees
(1927) from Cornell's College of Agriculture. She majored in cytology with
Lester Sharp in the Department of Botany, and minored in genetics and zoology
with A.C. Fraser and H.C. Reed in the Departments of Plant Breeding and
Zoology, respectively. As a graduate student, McClintock was a research
and teaching assistant in the Department of Botany. During these years,
Sharp referred both botany and plant breeding graduate students and post-doctoral
researchers to her. Most notable were George Beadle (Ph.D. 1930), who learned
cytology from McClintock and went on to head the biology division at Caltech
and to win a Nobel Prize, and L. J. Stadler (NRC Fellow 1926) later elected
to the National Academy of Sciences.
McClintock's career as one of the most prominent geneticists of the 20th
century was launched while she was at Cornell. Upon receiving her doctorate,
McClintock was made an Instructor. At that time, this appointment was the
first step leading to tenure at colleges and universities like Cornell.
Jobs in academia were scarce during the Depression, and jobs for women were
limited. While employed at Cornell, Instructor McClintock continued to mentor
and collaborate with graduate students. She befriended graduate student
Marcus Rhoades (Ph.D. 1932), who also rose to preeminence in genetics and
was McClintock's lifetime supporter. From 1927 to 1931, she taught undergraduate
and graduate courses in Cornell's Department of Botany.
In early 1929, McClintock
published her Ph.D. dissertation in Genetics, then the foremost journal
in the field. Within two years, she had published six other articles in
major journals, all of which made important contributions to the newly emerging
field of plant cytogenetics, and furthered the world's knowledge about the
location of genes on chromosomes. She collaborated with students on the
most notable of these investigations.
gave graduate students Henry Hill and Harriet Creighton two important projects
for their thesis research and co-authored these pioneering contributions
with them. The first was a method to connect chromosomes with linkage groups
in corn (McClintock & Hill 1931) and the second was the cytological
proof for crossing over (McClintock 1931, Creighton & McClintock 1931).
Creighton and McClintock's significant study gave further confirmation to
T. H. Morgan's chromosome theory of inheritance, for which he won a Nobel
Prize in 1933. These collaborative projects were based on important work
that McClintock had pioneered: identification of corn's ten chromosomes
at mitosis (and later at meiotic pachytene stage), confirmation of Belling's
translocation hypothesis, and the sequence of the genes in Chromosome 9.
Creighton (Ph.D. 1933) became head of Botany at Wellesley College and President
of the Botanical Society of America in 1956.
From 1931 through 1934,
sponsored by two National Research Council Fellowships, and a prestigious
Guggenheim Fellowship, McClintock traveled to a series of important research
institutions across the U.S., Germany, and back to Cornell, where she worked
in the Department of Plant Breeding as an assistant to R. A. Emerson, head
of the department. There, she conducted research, funded by the Rockefeller
Foundation, which would provide insights to an understanding of variegation
and would eventually lead to her Nobel award winning investigations.
In 1936, McClintock
accepted an appointment as Assistant Professor of Botany at the University
of Missouri to join L. J. Stadler's genetics research group. Upon learning
that the research unit might be eliminated, and preferring research over
teaching, McClintock requested a leave of absence from Missouri in 1941
to seek employment elsewhere. In 1943, she accepted a position as a permanent
staff member of the Carnegie Institution of Washington's Department of Genetics
at Cold Spring Harbor. It was there she discovered mobile genetic elements
in corn for which she was awarded the Nobel Prize in Medicine or Physiology
in 1983. She remained at Cold Spring Harbor for the duration of her career,
accepting only short term appointments at national and international institutions
considerable recognition within her lifetime. In 1944, prior to her most
celebrated work, she was elected to the National Academy of Sciences, the
third woman so honored. McClintock also became the first woman elected Vice
President (1939) and President (1945) of the Genetics Society of America.
By 1947, she received the Achievement Award from the American Association
of University Women.
But it is for McClintock's
work with maize at Cold Spring Harbor beginning in the mid 1940s, her meticulous
observations of the dynamism of the genome, her communications of her theory
of genetic transposition-the idea that genes could change their position
on a chromosome-that cemented her reputation as a geneticist, which was
widely acknowledged in later years. In 1957, the Botanical Society of America
recognized her achievements with their esteemed Merit Award, and Cornell
appointed her one of their first A.D. White Professor's-at-Large in 1965
(renewed in 1971).
McClintock also won
a number of prizes during her later career. A few months before she formally
retired in 1967, she received the Kimber Genetics Award from the National
Academy of Sciences. In that year, the Carnegie Institution of Washington
appointed her a Distinguished Service Member, one of their highest honors,
which made it possible to continue working at Cold Spring Harbor Laboratory.
During the 1970s she received the National Medal of Science (1970), the
Lewis S. Rosensteil Award (1978), and the Louis and Bert Freedman Foundation
Award (1978). A few years before receiving the Nobel Prize, she was honored
with many awards; more notable were the Thomas Hunt Morgan Medal, the Wolf
Foundation Prize in Medicine, a shared Albert Lasker Basic Medical Research
Award, and the first Prize Fellow Laureate of the MacArthur Foundation.
McClintock's life as
a scientist was not always easy. Full appreciation of the implications of
her work, which challenged generally held beliefs that the chromosome had
a stable structure, was not possible until molecular biologists found similar
phenomena in bacteria and other organisms. As one of the early women scientist
in this country, McClintock was recognized early on for her pioneering achievements;
gaining a star in American Men of Science by 1944. Yet, as an aspiring
young geneticist, she experienced rejection because of her gender. Determined
to succeed in her chosen field, and respected and helped by devoted colleagues,
McClintock eventually found a position at an institution that gave her the
freedom to pursue her love of science and which, she said, "fit her
personality rather well."
--by Lee B. Kass, Visiting
Professor, Cornell University
COE, ED & LEE B. KASS. 2005. Proof of physical exchange of genes on
the chromosomes. Proceedings of the National Academy of Science 102
(No. 19, May): 6641-6656.
COMFORT, NATHANIEL C. The Tangled Field: Barbara McClintock's Search
for the Patterns of Genetic Control. Harvard University Press, 2001
[see critical book reviews by NINA FEDOROFF. 2002. The well mangled McClintock
myth. Trends in Genetics 18 (7): 378-379, and LEE B. KASS. 2002.
The Tangled Field, by N. Comfort. Isis. 93 (4): 729-730].
FEDOROFF, NINA & DAVID BOTSTEIN, editors. 1993. The Dynamic Genome:
Barbara McClintock's Ideas in the Century of Genetics. Cold Spring Harbor
KASS, LEE B. 2000. McClintock, Barbara, American botanical geneticist, 1902-1992.
Pp. 66-69, in Plant Sciences, edited by R. Robinson, Macmillan Science
KASS, LEE B. 2003. Records and recollections: A new look at Barbara McClintock,
Nobel Prize-Winning geneticist. Genetics 164 (August): 1251-1260.
KASS, LEE B. 2005a. Missouri compromise: tenure or freedom. New evidence
clarifies why Barbara McClintock left Academe. Maize Genetics Cooperation
Newsletter 79: 52-71
KASS, LEE B. 2005b. Harriet Creighton: Proud Botanist. Plant Science
Bulletin 51(4): 118-125.
KASS, LEE B. and CHRISTOPHE BONNEUIL. 2004. Mapping and seeing: Barbara
McClintock and the linking of genetics and cytology in maize genetics, 1928-1935.
Chap. 5, pp. 91-118, in Hans-Jörg Rheinberger and Jean-Paul Gaudilliere
(eds.), Classical Genetic Research and its Legacy: The Mapping Cultures
of 20th Century Genetics. London: Routledge.
KASS, LEE B. CHRIS BONNEUIL, & ED COE. 2005. Cornfests, cornfabs and
cooperation: The origins and beginnings of the Maize Genetics Cooperation
News Letter. Genetics 169 (April): 1787-1797.
KELLER, EVELYN FOX.1983 (reprinted 1993). A Feeling for the Organism:
The Life and Work of Barbara McClintock. W.H. Freeman & Co..
Photo above: Cornell University 1929: (from right to left) Instructor Barbara
McClintock with Professor R.A. Emerson and his graduate students Marcus
Rhoades and George Beadle (kneeling), and Post-doctorial National Research
Council Fellow Charles Burhnam (used with permission of W. B. Provine).
Margaret E. McCully, Ph.D, F.R.S.C.
Margaret E. McCully was born in St. Marys, Ontario, Canada. After receiving
her bachelor’s degree in agriculture at the University of Toronto in 1956,
she taught chemistry and biology at Shelburne High School in Ontario before
returning two years later to the University of Toronto to complete her master’s
degree in plant ecology. For her degree, Margaret studied the morphology
and ecology of the common Mare’s tail, Hippuris vulgaris. After moving to
England where she taught for two years in an English school, Margaret returned
to North America in 1966 to study at Harvard, where she completed her Ph.D.
in cell biology on the histology of the brown alga Fucus. She came back
to Canada to take a faculty position at Carleton University in Ottawa where
she spent the vast majority of her academic career.
Margaret’s diverse training has given her a broad outlook. She has touched
upon many areas of science, from phycology to microbiology, from anatomy
to physiology. Along with T.P. O’Brien, Margaret co-wrote a reference book
for microscopists entitled “The Study of Plant Structure—Principles and
Selected Methods”; this book is used throughout the world and contains a
wealth of information of plant histochemistry and cytology. Margaret is
best known, however, as an expert in root biology and her papers on this
topic illustrate the broad base of her studies; she is as much at ease writing
about techniques to study roots as about their anatomy and physiology. Root
structure, root development, root behavior in the field, biology of the
rhizosphere, water status of the plant, ion uptake, lateral root development,
techniques for microscopy (light, fluorescence, electron), x-ray microanalysis—all
of these are grist for Margaret’s mill. She has published more than a hundred
papers in internationally refereed journals, and in the process, she has
changed our views about many of these fields. One of the most significant
findings, done in collaboration with Martin Canny, her husband, is that
water does not enter the field-grown corn roots just near their apices but
rather along their entire length. A description of this research can be
found in the 1999 Annual Review of Plant Physiology and Plant Molecular
Biology, entitled “Roots in Soil: Unearthing the Complexities of Roots
and their Rhizospheres.”
Margaret is very well known internationally. She has held visiting fellowships,
lectureships, or professorships at the University of Leeds and Oxford University
in the United Kingdom; the University of California, Davis in the United
States; and Monash University, the University of Melbourne, LaTrobe University,
and the University of Western Australia in Australia. She was elected a
Fellow of the Royal Society of Canada in 1987, and in 1993 received a degree
of D.Sc. (honoris causa) conferred by St. Mary’s University in Halifax,
Nova-Scotia, Canada. Margaret has received a number of other honors, including
two Carleton University Academic Staff Association Scholarly Achievement
Awards and a major research achievement prize from Carleton University.
In 1996, she was awarded the Lawson Medal Award from the Canadian Botanical
Association, and in 1994, she was invited to give the Hamm Lecture at the
University of Minnesota in Minneapolis. In 1999, she and her work were recognized
at the XVI International Botanical Congress in St. Louis, Missouri. A symposium
was organized to honor her outstanding contributions to root biology and
to plant science.
In addition to her science, Margaret McCully has been a tremendous role
model for numerous students, postdoctoral scholars, and research associates.
Margaret has been and still is a very demanding scientist, asking as much
from her students as from herself; she has always looked for high standards
and honesty. However, she has been very generous with her time and her scientific
expertise, and also with her knowledge of literature, music and art. In
spite of her success, Margaret continues to be genuinely interested in talking
with students, undergraduate or graduate alike. She encourages her students
to attend conferences, to present their work, and to talk with other participants.
Very early on, she taught those of us who worked with her to “network,”
to communicate not only with our peers, but also with her friends and colleagues,
highly regarded scientists. Margaret encouraged her students to keep open
minds and eyes to the outside world, advising them to focus broadly and
not only on the tiny portion of roots they studied. Although her studies
concentrated on plant organs, she never lost the sense of the organism.
This is why in her lab, even though sometimes students worked on roots growing
in Petri plates, they still thought of what they learned as being applied
to real roots, growing in real soil. She taught students that model systems
were good but only as a step to understand the bigger picture.
Margaret has been an extraordinary teacher because she is a wonderful
human being. She surely put a mark on all the persons who passed through
her laboratory, including the author of this biography. In Margaret’s lab,
we learned on old pieces of equipment before being allowed to use the new
microscope or new microtome. This was not because Margaret was worried about
the state of the equipment, but rather it ensured that we understood the
mechanisms of the machine before we went on to work with the more sophisticated
equipment. We would be able to go anywhere in the world, and work with any
piece of equipment--old or new, because we understood how it functioned.
Also, because of her respect for the old literature, she taught us to read
it and to use it in our research. Anatomists and microscopists of the last
centuries had already observed so much!
Although Margaret retired from Carleton in 1999 and subsequently moved
to Australia, she continues to do research and work with new groups of students,
thus conveying her enthusiasm and her love for science.
Frédérique C. Guinel, Wilfrid Laurier University.
Arlette Nougarède was an active French cytologist in the field of plant
morphogenesis during the last half of the twentieth century. Her name will
remain associated with the elucidation of the cytophysiological organization
of the angiosperm shoot apical meristem during both vegetative and reproductive
She was born on May 7, 1930, at Narbonne in the south of France, and moved
to Paris in 1948 following the completion of her secondary studies. After
brilliantly passing the basic degrees at the Faculty of Sciences of Paris,
she became a C.N.R.S. associate researcher and prepared a doctorate at the
Ecole Normale Supérieure. This was the beginning of a fruitful and exemplary
career. She obtained her doctorate degree in 1958 and became a lecturer
at the Faculty of Sciences of Paris in 1959, and finally a professor at
the Pierre and Marie Curie University in 1961, where she created her own
Laboratory of Experimental Cytology and Plant Morphogenesis. Arlette extended
the focus of her research group to several domains of plant development
including lateral rhizogenesis, bud dormancy, gravitropism, and root and
shoot meristem regeneration in tissue culture, using a range of methods
that allowed not only structural and ultrastructural approaches, but also
a comprehensive analysis of the phenomenon under study. Many times over
Arlette developed new methods for combining physiological and dynamic information
with descriptive cytological data. For example, she was the first to use
histoautoradiography and DNA microspectrophotometry to study plant material
in France. This approach enabled her to obtain precise information on the
parameters of cell cycle activity in apical meristems at various developmental
stages, including the total duration of the cell cycle, the duration of
each phase, and the position of specific cells in the cycle. Her pioneering
work in this area is confirmed today by molecular genetic studies of the
cell cycle. Her findings opened the way to modern approaches of plant developmental
Confronted by serious health problems at different times of her life,
Arlette proved to be exceptionally courageous and never stopped urging work
along, even when hospitalized and close to being blind. During her productive
scientific career, Arlette wrote 146 original and review papers. She participated
actively in the major congresses on plant morphogenesis, which led to several
collaborations with American and European colleagues. Among the 18 doctoral
students she supervised, six are now professors in various universities
and nine are associate professors.
Arlette was also an excellent teacher, not only on the topic of plant
morphogenesis, but also on basic cell biology and general botany. In 1969,
she wrote a comprehensive textbook of cytology, which was a major reference
book at that time. Her lectures were always very thorough, and she was a
mentor for many students who decided later to become teachers, scientists,
or both. She was as demanding of herself as she was of others. When we,
her students, were younger, we felt sometimes rather intimidated by Arlette,
but her professional rigor was always compensated for by her readiness to
lend support and a helping hand to all.
When she retired in 1991, a colloquium was organized by her former students
in her honor under the aegis of the French Society of Botany. Throughout
her career, Arlette received a number of honors and distinctions from the
French Academy of Sciences of which she is now a corresponding member. From
the French government she received the titles Chevalier de la Légion d'honneur,
and Officier des Palmes académiques. She is also a member of the Botanical
Society of America and of the Society of Biology.
Arlette has recently written a review article (Nougaréde, 2001) synthesizing
the views of cytologists and molecular biologists on the concepts developed
around the shoot apical meristem. This paper shows once again the open-mindedness,
vision, intelligence, and capacity to integrate new ideas that characterize
great scientists. There is no doubt that she would have loved to participate
in the new developments in her favorite areas of research using the genetic
tools that are available today.
As an Emeritus Professor, she remains in close contact with her former
lab, of which the author of this biography is now the director. Moreover,
as one of her students, it is with a feeling of sincere admiration and affection
that I think of the life and work of Arlette, who was a most inspiring teacher.
Dominique Chriqui, University Pierre and Marie Curie, Paris
Some significant papers from Arlette Nougarède
Experimental cytology of the shoot apical cells during vegetative growth
and flowering. Intern. Rev. Cytol. (1967) 21, 203-351.
Méristèmes. Encyclopaedia Universalis (1985) vol. 11,
Chrysanthemum segetum L. In: Handbook of flowering,
(1989) vol. VI, Halevy A. H. ed., CRC Press, Boca Raton, U. S. A., pp. 196-227.
Le méristème caulinaire des Angiospermes : nouveaux outils, nouvelles
interprétations. Acta Bot. Gallica (2001) 148 (1), 3-77.
Ann Oaks, B.A., M.A., Ph.D., F.R.S.C.
Oaks was born and raised on the frontiers of Canada, and spent her career
at the frontiers of plant research. Her early upbringing in austere, but
caring conditions instilled in her a strong independent will, and a keen
sense of survival, as well as a lasting interest in, and compassion for
Her higher education was at the University of Toronto in honors biology,
where she developed an interest in plants, with the encouragement of Norm
Good. She became excited by courses in physiology and biochemistry during
her final years as an undergraduate, but maintained her interest in nature
by working in the north during the summer months. After a year in Churchill,
Manitoba, looking at cold hardiness in Chironomids, she studied the genetics
and physiology of Chl-deficient mutants in barley for her master's degree
at the University of Saskatchewan with Michael Shaw and Tom Arnason. Following
a brief spell in Roy Waygood's lab and time at the College of Education
in Toronto, she returned to Shaw's lab in Saskatoon to complete her Ph.D.
on host--parasite relationships of wheat rust. There, her interest in plant
biochemistry was solidified when she took a course from Arthur Neish. Then,
in the late 1950s, as an Alexander von Humboldt scholar in Freising, she
worked with Otto Kandler on the path of C in photosynthesis, before moving
on to Harry Beever's lab in Purdue where she was initiated into the two
interests that influenced the rest of her career: maize seedlings and nitrogen
metabolism. She was appointed an assistant professor at McMaster University
in 1965 and retired from there as a professor 24 years later. She then transferred
her research to the University of Guelph as an adjunct professor for ten
Ann's research career has been extensive and highly successful with many
publications and seminal reviews; she has received the Gold Medal Award
from the Canadian Society of Plant Physiologists, and has been inducted
into the Royal Society of Canada. Major contributions have been made to
our understanding of the hydrolysis of protein reserves in the endosperm
of germinated maize, but arguably her more recognized research has been
to elucidate the pivotal role of nitrate reductase (NR) in the nitrogen
status of maize seedlings. The hydrolysis of maize endosperm reserves to
support seedling growth was shown in her lab to require the activity of
unique sets of proteases. These act in a two-step process; initially there
is cleavage of the insoluble zeins by a specific endopeptidase and the soluble
products of this are then sensitive to hydrolysis by less specialized endo-
and exo-peptidases. The reduced N released from the maize endosperm then
has a profound effect on ability of the seedling to take up and assimilate
nitrate-N. Ann and her coworkers have established the importance of the
balance between amide-N and carbohydrate supply in the induction of NR and
on the N-economy of the growing seedling. This understanding of the complexities
of nitrogen/nitrate metabolism at the physiological and biochemical level
has provided an essential prelude to the modern molecular era in which gene
activity and interactions are being elucidated. Ann developed and cherished
working relationships with researchers from India, Japan, Europe and N.
America. She, and her students and collaborators, laid some of the foundations
upon which modern technologies are being successfully applied.
Following retirement, her interests turned more strongly to the environment,
providing often strident opinions to groups questioning the wisdom of utilizing
water resources for commercial gain, the flagrant use of pesticides and
herbicides, and especially what she felt was the under-tested introduction
of genetically-modified organisms. She was a generous supporter of environmental
groups, arts groups and charities; she financed an annual lecture in the
College of Biological Sciences at the University of Guelph, as well as creating
a munificent endowment to support graduate students through the Canadian
Society of Plant Physiologists Ann Oaks Scholarship Fund.
Ann passed away, after a long and frustrating illness on Jan. 13th, 2006
at the age of 76. She recognized, espoused and imbued in her undergraduate
and graduate students and colleagues the values of mentoring, of constantly
challenging and questioning, and of personal discussions and contact. As
a teacher, researcher, and innovator, she has made a difference.
J. Derek Bewley, University of Guelph
(Helen) Beatrix Potter, beloved English children's author and illustrator
of The Tale of Peter Rabbit and Benjamin Bunny, was also a woman
pioneer in botany. Although she was born to privilege in 1866, Victorian
society did not encourage women to be successful or independent. Beatrix
was lonely and shy as a child, and many times her only companions were her
pets, wild animals she and her brother smuggled into their rooms. Probably
because of her isolated childhood, self-reliance came naturally to her.
From an early age, she produced excellent drawings. Her subjects were mostly
the animals, insects, and plants that she collected, all drawn with sensitivity
As a young woman Beatrix Potter developed an interest in classifying,
dissecting, and drawing fungi. Through this work and her research at the
British Museum, she became convinced that lichens were a symbiotic association
between fungi and algae. Although we now view her research and conclusions
to be an excellent example of pioneering work in the field, her work was
not accepted at the time. For example, in 1897, she prepared a research
paper on the symbiosis of lichens entitled "On the Germination of the Spores
of Agaricineae" for the Linnean Society. However, as a woman in Victorian
England, she faced resistance on all fronts. First, because women were unwelcome
at meetings, she was not able to read her paper before the Linnean Society
membership. Although her uncle, Sir Henry Roscoe, a distinguished chemist,
read Potter's paper at the meeting, her novel ideas about the symbiosis
were rejected. Finally, her future research opportunities were compromised
because she was now unwelcome to continue her work at the British Museum.
Although Beatrix remained a keen observer of nature for rest of her life
as reflected in her Peter Rabbit illustrations, the encounter with the Linnean
Society essentially ended her career as a practicing scientist.
Beatrix's career as children's author and illustrator began with an illustrated
letter to the children of her ex-governess. It was the basis of The
Tale of Peter Rabbit. After much success with her initial publication,
Beatrix immersed herself in her new venture, writing and illustrating many
wonderful tales. Because each new book was enthusiastically received, Beatrix
wrote and illustrated 21 more children's picture books. Eventually, she
earned quite a lot of money, which gave her financial independence. With
the royalties from her books, she purchased a small farm in the Lake District,
called Hilltop Farm, where she found a new focus for her energies and talents:
looking after her farm, caring for her animals, and supervising her home.
Hilltop farm was a very important part of Beatrix's world. The farm and
the environs brought her close to nature and inspired her later books. However,
it was a private world that only very few of her friends and family every
glimpsed or understood.
Beatrix and her husband, William Heelis, a local solicitor, became important
figures in the village of Sawrey, and they always gave back to the community
that had given them so much. For example, they purchased many of the historic
farms of the region to preserve them. Even in later years when health problems
began to sap her energies, Beatrix continued to be an ardent naturalist,
and science always remained important to her. For example, she selectively
bred prize-winning Herdwick sheep.
Beatrix died quietly in the winter of 1943, leaving behind a legacy of
timeless literature that continues to amaze and entertain children of all
ages. However, sadly because of the times in which she lived, she never
had the opportunity to develop her original interest in scientific research.
One wonders what would have happened in another time.
William Eisinger, Ph.D., Department of Biology, Santa Clara University
Judith Eisinger, M.S.L.S., San Jose Public Library
References and Suggested Readings
Buchan, E. 1987. Beatrix Potter: The Story of the Creator of Peter Rabbit.
Sapp, J. 1994. Symbiosis: Evolution by Association. New York, Oxford Press.
Ruth L. Satter, Ph.D.
Ruth L. Satter was a distinguished plant physiologist who worked on the
mechanism of leaf movement. Her career as a scientist was quite unusual,
very successful, and she enjoyed it thoroughly. Other aspects of her life
were also very interesting and heart-warming, and thus it is fitting to
remember her as a role model for women in science.
Ruth was born in 1923 in New York City and grew up in Lawrence, Long Island.
She graduated from Barnard College in 1944 with a bachelor’s degree in mathematics
and physics. Between 1944 and 1947 she worked at Bell Laboratories and at
Maxson Co. For the next 17 years she stayed home to raise her four children.
In 1964, when her youngest child was 2 years old, she started her study
of plant physiology as a graduate student at the University of Connecticut
at Storrs, in part because she loved gardening and wanted to understand
plants better. At that time, it was quite unusual for a 41-year-old woman
with four children to undertake a serious study of science. Her Ph.D. thesis
was on control of flowering by red/far-red light in Sinningia species
(Gloxinia), and her Ph.D. advisor Donald Wetherell believes she got the
idea from her observation of the plants growing in her window at home.
In 1968, she moved to Yale University as a postdoctoral fellow and began
studying the mechanism by which leaf movements in some legumes are controlled
both by light and by the circadian clock. At Yale, she published a series
of elegant papers that clearly showed that the basis of leaf movement was
due to changes in K+ and Cl- content in the cortical cells of the pulvinus,
and that both red and blue light phase-shift the rhythmic leaf movements.
In 1980, she returned to the University of Connecticut as a professor-in
residence in the Biological Sciences Group. Although not a tenure-track
position, she did not complain, but instead concentrated on understanding
the mechanism of rhythmic changes in ion contents in the motor cells of
the pulvinus. She found that a light-sensitive H+ pump generated the driving
force for K+ and Cl- fluxes into these cells. To quantify the ionic interactions
precisely, she and postdoctoral fellow Holly Gorton developed methods to
isolate protoplasts from the motor cells. It was very difficult to establish
a reliable protocol to isolate healthy protoplasts from the tough tissues
of the Samanea pulvinus, but they were successful. The protoplasts were
then used, by means of the newly developed patch clamp technique, to identify
the ion channels responsible for the osmotic and turgor pressure changes.
Her collaborator on this project was Nava Moran, who continued researching
the system to identify the mechanism of rhythmic and light-controlled regulation
of ion fluxes.
At this time, in the mid-1980s, the biological community was becoming
increasingly interested in signal transduction—how cells sense and transduce
environmental and internal signals to produce responses. Many interesting
examples of signaling pathways had been described in animal systems, and
Ruth wanted to test whether leaves used one of these signaling pathways
to sense and transduce light signals. She collaborated with Richard Crain,
a lipid biochemist, and together they showed that the phosphatidylinositol
cycle is the basic light signal transduction mechanism in the leaf motor
cells. Thus, the motor cells became one of the very first plant systems
shown to have the phosphatidylinositol cycle for signal transduction. In
the lab, she treated her students as equals and expected them to generate
ideas as good as hers. She took them to as many scientific meetings as possible,
gave them plenty of time to think and read, and provided journal clubs and
seminars for stimulation. She was delighted to recruit good students from
foreign countries because she wanted to help young people in need. She invited
her students to her home frequently and shared her culture with the foreign
students. She also wanted to learn about other cultures and was open about
the different ways people live.
All through her career, Ruth was happily married and was an enthusiastic
mother and grandmother. When she accepted new students in the lab she took
great care of them; it was as though she was expanding her family. She loved
to help people develop their talents and establish a happy life, which for
her, was very important, even more so than her own research. To young women,
she was an excellent example of how a woman could combine career and family
life, and she encouraged them to do so. Nava Moran, a senior lecturer at
the Department of Agricultural Botany, Hebrew University School of Agriculture,
one of the young women influenced by Ruth, had this to say: “Ruth was the
first and so far the only woman that became my role model both professionally
and as a person. She knew a lot about things I didn’t know, but was genuinely
interested in new subjects and aspects of old subjects, was eager to learn
new techniques and new approaches. I saw this when she was my student in
the patch-clamp course in Woods Hole. … What I really appreciated a lot
about her was her devotion to her family—she could share the time between
science and family—and also the freedom of decision she gave her daughter
Jane to go to El Salvador as a doctor. She was so proud of her then! ” Ruth,
her husband Bob and their children were very conscious of the need to serve
in ways that would improve society and the world. Her daughter Jane went
to El Salvador during their civil war to help as a physician. Ruth must
have been terribly worried about her daughter’s security, but she did not
try to dissuade her and instead was proud that Jane was serving the human
community. At various times Ruth served as a member of the Governing Board,
Executive Committee, and Editorial Board of the American Institute of Biological
Sciences. She was the Northeastern Region chairperson of ASPP, councilor
for the American Society for Photobiology, Editorial Board member of Plant
Physiology, and served as a peer reviewer and on postdoctoral fellowship
panels for the National Science Foundation. She was particularly concerned
about children’s and women’s issues and actively participated in American
Women in Science.
Ruth was diagnosed with leukemia in 1980 and her research was often interrupted
due to her medical problems. However, she came back again and again to the
lab with a big smile. Her love of science was a great inspiration for everyone
in the lab. Despite her enthusiasm about life and science, her health deteriorated
gradually, and by 1989 she had to have blood transfusions every week. In
the late summer of 1989, she decided not to fight any longer. She was 66,
felt good about her whole life, and gracefully accepted death. Many in the
field of plant physiology still miss her insight as a scientist and most
of all, her friendship.
Youngsook Lee, Pohang Institute of Science and Technology, Korea
Helen Stafford, Ph.D.
Helen Stafford was born in Philadelphia, Pennsylvania, on October 9, 1922,
and attended Friends schools through high school. Her parents had both attended
college, and Helen entered Wellesley College on a scholarship, where she
earned her B.A. degree in Botany in 1944. She then spent one academic year
(1945-46) at Cornell University as a research assistant to M. Knudsen and
working with orchid cultures. Helen received a two-year assistantship with
Richard Goodwin and transferred to the Connecticut College for Women in
1946, where she earned her M.A. degree in 1949. Her thesis research on the
growth and xylary development of Phleum pratense seedlings resulted
in her first publication in the American Journal of Botany (1948.
35: 706-715). Helen spent the next three years with David
Goddard in the Botany Department at the University of Pennsylvania, where
she received her Ph.D. in 1951. Her doctoral research showed cytochrome
oxidase and succinic dehydrogenase in pea mitochondria and was among the
first research on cellular localization of enzymes in plant tissues using
differential centrifugation of cell-free homogenates. Her first review in
the Annual Review of Plant Physiology (1959. 5:
115-132) entitled "Localization of Enzymes in the Cells of Higher Plants"
and co-authored with Goddard, established Stafford as an authority on this
Helen's next three years were spent as a post-doctoral scholar at the
University of Chicago where she worked with Birgit Vennesland studying NAD+/NADP+
dependent dehydrogenases acting on hydroxyacids in plants. At that time,
the relationship of these organic acids (found only in plants) to the di-
and tricarboxylic acids of the Krebs cycle was not at all clear. During
that time she also taught general plant biology, one of five sequential
biology courses in the fabled undergraduate College at Chicago. Helen's
research at Chicago resulted in several papers on plant dehydrogenases,
including the first publication on alcohol dehydrogenase in plants.
Helen's ability both to teach bright science undergraduates and to conduct
research publishable in leading journals, made her a prime candidate for
an assistant professorship in the Department of Biology at Reed College
in Portland, Oregon. She joined that department in 1954, at a time when
the small biology program (three faculty) was being reorganized, slowly
expanded, and its goals undergoing unique changes. Along with a few far-sighted
colleagues, she helped design a highly successful, research-intensive training
program for undergraduates involving faculty members who also would maintain
a vigorous research program. New staff members were chosen for their teaching
abilities as well as for their potential to conduct research that was funded
by NSF, NIH, and private sources. Helen obtained her first NSF grant in
1955, and received continuing renewals thereafter, until one year after
she retired in 1987. With such support, Helen produced a body of excellent
work in an institution that has no graduate degree programs. However, every
student at Reed is required to do a senior's thesis, and most of her later
co-authors were students who have gone on to graduate school and are now
productive scientists in their own right.
At Reed, Helen continued working on organic acids in plants, especially
the aromatic phenolic acids that serve as precursors of lignin. This directed
her attention to that biopolymer for a few years. Following a sabbatical
year (1963-1964) as a NSF Senior Postdoctoral Fellow in Ted Geissman's laboratory
in Chemistry at UCLA, Helen's interests centered on flavonoids, especially
anthocyanins. This research led to her second "annual review" article on
the metabolism of aromatic compounds (Annual Review of Plant Physiology.
1974. 25: 459-486). Through examination at different levels-the
enzymes involved, their cellular localization, the biosynthetic sequences
involved, their physiological role(s)-her efforts have contributed major
concepts to the better understanding of aromatic compounds. Helen was the
first plant biochemist to postulate that secondary biochemical pathways
can be compartmentalized within multi-enzyme complexes (Recent Advances
in Phytochemistry. 1974. 8: 53-79). This was a major
advance because such a hypothesis could account for the often-massive flow
of carbon from photosynthesis into plant products without reactive intermediates
undergoing wasteful side reactions. Helen also proposed that those pathways
that involve metabolic "grids" offer opportunities for metabolic regulation.
These two concepts are discussed in detail in her treatise on flavonoids
(Flavonoid Metabolism. 1990. CRC Press).
In the preface to her book, Helen identifies a second major shift in her
research interests to proanthocyanidins (condensed tannins) after she spent
a sabbatical with T. Cheng at the Oregon Graduate Center in Portland. Two
reviews, resulting from her numerous research papers on these complex substances
in the following decade, have clarified information about their structures,
biosynthesis (Chemistry and Significance of Condensed Tannins.
1989. R. W. Hemingway and J.J. Karchesky, eds., Plenum Press), and their
relation to lignin (Phytochemistry. 1987. 27:
1-6). Because her career in plant biochemistry and physiology has been both
broad and deep, Helen continues to write stimulating papers such as those
listed at the end of this biography.
In addition to her teaching and research career at Reed, Helen Stafford
has served the plant sciences in numerous ways. She was a member of the
editorial board of Plant Physiology for nearly 30 years (1964-1992).
She was a CUEBS Commissioner (1968-1971) and a member of the NSF panel on
metabolic biology (1973-1975). Helen has served as president of the Phytochemical
Society of North America (1977-1978) and Editor-in-Chief (1989-1993) of
its serial publication Recent Advances in Phytochemistry. This
series has chronicled research in plant biochemistry for 32 years, especially
in the area of plant natural (secondary) products. In 1996, Helen received
the Charles Reid Barnes Life Membership Award of the American Society of
As a distinguished woman pioneer in plant biochemistry and physiology,
Helen has been aware of unequal treatment for women in science. She was
the first woman allowed to teach male botany students at the University
of Pennsylvania in 1949. At Reed, she was the only female faculty member
in the sciences (Mathematics, Physics, Chemistry, and Biology) for many
years. Today there are three women among 10 faculty members in Biology.
In summary, Helen Stafford is not only recognized internationally for
her research, but also as an influential teacher in one of the country's
premier undergraduate colleges. She has shown her students the excitement,
pleasure, and rewards of having a distinguished research career.
Eric C. Conn, University of California, Davis
2008 Phytochemistry Pioneer Award PPT
Some Papers of interest by Helen Stafford
Flavonoid Evolution: An Enzymic Approach (Plant Physiology. 1991.
Anthocyanins and Betalains: Evolution of the Mutually Exclusive Pathways
(Plant Science. 1994. 101: 911-98).
Metabolism and regulation of Phenolics: Gaps in our Knowledge (in: Phytochemicals
and Health, Current Topics in Plant Physiology. 1995. 15:15-30).
Teosinte to Maize: Some Aspects of Missing Biochemical and Physiological
Data Concerning Regulation of Flavonoid Pathways (Phytochemistry,
1998. 49: 285-293).
The Evolution of Phenolics in Plants (Recent Advances in Phytochemistry.
2000. 34: 25-54).
Birgit Vennesland, Ph.D.
Birgit Vennesland and her sister Kirsten were born on November 17, 1913,
in Kristiansand, Norway. Their father had immigrated to Canada shortly after
graduating from high school, but made several trips back to Norway to woo
and eventually wed their mother, a schoolteacher. The newlyweds went to
Calgary after honeymooning in Germany, and when they learned she was pregnant,
their mother returned to Norway to give birth in Kristiansand. Their father
entered the United States to study dentistry in Chicago, where he eventually
obtained his D.D.S.
As she wrote in her prefatory chapter in Annual Reviews of Plant Physiology
(32:1-20 ), their parents "tired of waiting for the
end of World War I" and in May 1917 their mother sailed for the United Sates
with her daughters to rejoin the father in Chicago. Both girls rapidly became
bilingual, learning English from their friends at school while speaking
Norwegian at home. Because their parents greatly valued education, their
home overflowed with books, both Norwegian and English.
Vennesland entered the University of Chicago in 1930 on a scholarship
awarded to her on the basis of a competitive examination in physics. Robert
Maynard Hutchins, the new university president, was "reorganizing" college
education, and Vennesland entered the last class operating under the "old"
plan. She therefore enjoyed the benefits of both systems, and enrolled in
a general science course entitled "The Nature of the World and Man". Top
science faculty, each of whom gave a few lectures in their specialty, taught
this course, which began with astronomy and ended with zoology. It influenced
Vennesland to follow a pre-med program that allowed her a mix of the physical
and biological sciences. Eventually she settled on a biochemistry major
and received her B.S. degree in that discipline in the spring of 1934.
After brief employment as a research technician at the University of Illinois
Medical School, Vennesland recognized her need for more knowledge. So she
returned to the University of Chicago to do graduate work in biochemistry.
Biochemistry in the 1930s was the chemistry of small molecules such as vitamins,
amino acids, steroids and hormones that were being continuously identified.
It also included aspects of animal physiology such as diabetes, gluconeogenesis,
and ketogenesis. Metabolism, which would eventually clarify relationships
among these subjects, was largely unknown, although knowledge of some of
the enzymes involved was developing. The department's laboratory courses
emphasized analytical techniques suitable for blood and urine, and in hospital
laboratories some jobs were available for biochemists with such training.
Vennesland selected her own thesis project, the oxidation/reduction potential
of an obligate anaerobe, which she completed in 1938. During her thesis
research she observed that bacteria, including anaerobes, require small
amounts of CO2 to grow. This finding was to influence one of
her later research interests.
In 1939, Vennesland received a fellowship from the International Federation
of University Women that would allow her to work with Otto Meyerhof who
was then in Paris. But the war in Europe forced her plans to change, and
she went instead to Harvard to work in Baird Hastings' biochemistry department.
There she joined his team studying glycogen formation with the short-lived
(20 minute half-life) isotope of carbon, 11C, use of which required
careful planning and speedy work-up of experiments. While the research team
readily showed that 11C-labelled lactic acid gave rise to labeled
liver glycogen in starved rats, the more exciting finding was the incorporation
of 11CO2 into liver glycogen. This observation demonstrated
that there was "a pool of metabolites that contributed to liver glycogen"
that could be labeled by 11CO2. (B. Vennesland, 1991.
FASEB Jour. 5: 2868.)
Vennesland returned to the University of Chicago as an instructor in the
biochemistry department in 1941 where she intended to examine CO2
fixation reactions in non-photosynthetic plant tissues. However, heavy teaching
loads and involvement in a malarial research project on campus, resulted
in little else being done until the war finished. Then in the fall of 1946,
students began to return to graduate school, and Vennesland's research program
flourished. She had purchased a Beckman DU spectrophotometer, which became
commercially available only after the war and was essential for measuring
the oxidation/reduction of the pyridine nucleotides DPN+ and
TPN+ (as NAD+ and NADP+ were then called).
Her first students isolated enzymes such as yeast alcohol dehydrogenase,
rabbit muscle lactic dehydrogenase, Warburg's "old yellow enzyme" and "Zwischenferment"
(i.e. glucose-6-phosphate dehydrogenase); the two-last mentioned were utilized
in manometric assays of TPN+. Although ATP and DPN+
became commercially available from the Pabst brewing company about that
time, TPN+ had to be isolated from hog liver. This was accomplished
by two of her students using a procedure of Warburg's that had been carried
to the United States by Erwin Haas, one of his former technicians, and for
several years Vennesland's laboratory was the only source of TPN+
outside of Germany. Samples were given to such investigators as Leonard
Tolmach who, working in James Franck's and Hans Gaffron's photosynthesis
laboratory at Chicago, independently discovered that TPN+ could
act as a Hill-reagent and be reduced by spinach grana in a light-dependent
reaction. Also, Severo Ochoa and his postdoctoral associate, Arthur Kornberg,
received TPN+ with which they examined malic enzyme in animal
Equipped with such enzymes and their coenzymes, Vennesland and her students
began examining reactions of intermediary metabolism in plant tissues. (She
intentionally avoided examining reactions that might be involved in photosynthesis
because there was general agreement that research groups at Chicago should
not compete with each other.) As a result papers and reviews describing
research in plant tissues on the following enzymes appeared during the 1940s,
1950s and 1960s: TPN+-malic enzyme; alcohol, formic acid, glucose-6-phosphate,
phosphogluconate, glucose, D-glyceric acid, and dihydro-orotic acid dehydrogenases;
glutathione reductase; PEP carboxykinase; TPNH oxidase; dihydroxyfumaric
and hydroxypyruvic acid "reductases"; and glyoxalate carboligase.
In 1950 Vennesland and Frank Westheimer, then in the chemistry department
at the University of Chicago, initiated a collaboration that greatly advanced
our knowledge of the reaction mechanism of the pyridine nucleotide dehydrogenases.
In their first experiments, they and their students showed that the two
hydrogen atoms at carbon-4 of the dihydropyridine ring of DPNH and TPNH
(i.e., NADH and NADPH) are enzymatically non-equivalent, and that these
dehydrogenases transfer hydrogen (as hydride) stereospecifically between
substrates and coenzymes. This was the first experimental demonstration
of the enzymatic inequality of the two enantiotopic hydrogen atoms on the
methylene carbon atom of ethanol (see TIBS, 3:265-8
). It made possible the enzymatic synthesis of a pure enantiomorph
of ethanol-1-d. This discovery also permitted the classification
of pyridine nucleotide-linked dehydrogenases into two groups. The A-stereospecific
enzymes remove the hydrogen at the pro-R side of the dihydropyridine
ring, while B-stereospecific enzymes transfer the pro-S hydrogen.
This work therefore represented an early example of the non-equivalency
of the two identical groups on a pro-chiral carbon atom when an enzyme acts
upon substrates containing such atoms. Numerous papers on the enzymatic
transfer of hydrogen, and the stereospecificity of enzymes involved resulted
from this research. A stimulating review on stereospecificity in biology
and the Ogston hypothesis is authored by Vennesland in Topics in Current
Chemistry, 1974. 48:39-65.
With the departure of Gaffron (and the death of Franck), research on the
"light" reactions of photosynthesis terminated in their laboratory. Vennesland
then began work on the Hill reaction, showing that CO2 was required.
Research in her lab in the 1950s and 1960s therefore broadened considerably
as she and her students took up this new area but continued to examine plant
intermediary metabolism and the stereochemistry of enzymes. (A list of many
of her papers can be found in the chapter regarding Vennesland in Women
in the Biological Sciences, a bibliographic sourcebook, 1997, L. S.
Grinstein, et al. eds. (Greenwood Press, Westport, CT)). By 1968, Vennesland's
many research accomplishments had been recognized by her receipt of the
Stephen Hales Prize of the American Society of Plant Physiologists (1950),
an honorary D.Sc. from Mount Holyoke College (1960), and the Garvin Medal
of the American Chemical Society (1964).
Vennesland's investigations of the Hill reaction of photosynthesis, and
some shared views and common methodologies, led to several extended trips
to visit Otto Warburg at the Max Planck Institute for Cell Physiology in
Berlin during the early and mid-1960s. These visits resulted in an invitation
from Warburg to join the Institute as Director (and his handpicked successor).
She therefore left the University of Chicago in 1968 and moved to Berlin.
Promises and expectations were apparently not fulfilled and conditions (scientifically
and personally) worsened after her move to Berlin. The Max Planck Gesellschaft
came to her rescue and arranged for her move, in 1970, to a nearby Max Planck
Institute, designated the Forschungsstelle Vennesland (literally Research
Place Vennesland). Before this move, she had become intrigued with the possibility
that the controversial quantum yields reported by Warburg could be attributed,
in part, to the presence of nitrate in the medium. This led to her interest
in the process of nitrate assimilation in photosynthetic organisms, and
to her pioneering work in this and related areas from the early 1970s until
her retirement in 1984. Some noteworthy accomplishments during this period
were the first complete characterization of assimilatory nitrate reductase
(quaternary structure, identity and stoichiometry of prosthetic groups,
and site of regulation); identification of cyanide as a natural metabolite
in photosynthetic organisms and as a physiological regulator of nitrate
assimilation; and metabolic routes for cyanide formation in photosynthetic
organisms. For example, she found that cyanide is a major end product in
the oxidation of D-histidine, catalyzed by D-amino acid oxidase. Postdoctoral
associates who trained with her during this period carried on some of this
After retirement, Vennesland moved to Hawaii where her sister Kirsten,
a M.D., had gone in 1967 as the tuberculosis control officer for the U.
S. Public Health Service. Following Kirsten's death in 1995, Birgit Vennesland
moved to a retirement community in Kaneohe, HI. Following a short illness,
Birgit Vennesland died on October 15, 2001.
Birgit Vennesland was a remarkable scientist as evidenced by the breadth
and originality of her research. She was an outstanding role model who had
a lasting influence on the many students and postdoctoral associates who
worked with her over the years. Her fascination with science and approach
to research were contagious. A large number of these students and postdoctoral
associates went on to successful careers at prestigious institutions in
the United States and abroad, including two members of the National Academy
of Sciences (USA).
Eric E. Conn, University of California, Davis
Larry P. Solomonson, University of South Florida