Scientist Spotlight

The life of a scientist is not one path, it varies person to person. Proteintech's Scientist Spotlight is a monthly highlight of a scientist and their unique journey to discovery.

September Scientist Spotlight- Nettie Stevens

September, 2022 by Afrida Rahman-Enyart, PhD.

     This month’s “Scientist Spotlight” features geneticist Nettie Stevens, who made landmark discoveries in the fields of embryology and cytogenetics during her tragically short time as a scientist. Stevens is best known for her discovery of the sex chromosomes.

     Nettie Stevens was born in 1861 in Cavendish, Vermont as one of four children, two boys and two girls. Unfortunately, both of her brothers died at a young age. Additional tragedy struck the family in 1865 when Stevens’s mother also passed away. After her mother’s death, Stevens’s father remarried and the family moved to Westford, Vermont. As a carpenter, Stevens’s father was able to provide a quality education for his daughters. During the late 1800s, however, most women did not pursue professions beyond being a teacher, nurse, or secretary. Stevens did not want to follow this trajectory and, instead, dreamed of becoming a scientist.  

     At school, Stevens excelled in her studies and was one of three women to graduate from Westford Academy between 1872 and 1883. After graduating, she became a teacher with the hope of saving money to pay for higher education. After three years of teaching, Stevens went on to study at what is now Westfield State University. She graduated in two years at the top of her class. Afterwards, Stevens returned to teaching and worked as a librarian to save money for additional schooling. Finally, at 35, she was able to enroll at Stanford University, where she became specifically interested in physiology and histology. She received both her BA and MA in biology from Stanford. Stevens then went on to pursue her PhD in cytology at Bryn Mawr College under the mentorship of Thomas Hunt Morgan. Her thesis work focused on developmental biology and regeneration, including the development of sperm and eggs in sea urchins and worms. She did exceptionally well in graduate school and was even named a President’s European Fellow, which allowed her to study abroad in Italy and Germany. In 1903, Stevens received her PhD. She continued to a postdoc at the Carnegie Institution, where she received several grants to study heredity related to Mendel’s laws and sex determination. In 1905 she wrote a research paper and won an award for the best scientific paper written by a woman.     

     Stevens’s work on sex determination was groundbreaking. She observed that sperm from male mealworms sometimes contained a small chromosome (now recognized as the Y chromosome) or a large chromosome (now recognized as the X chromosome). She identified that whether a sperm carried the small or large chromosome determined the sex of the offspring, since all eggs carried only the large chromosome. She concluded that the male partner determined the biological sex of progeny. Stevens’s discovery was the first time that scientists had been able to physically observe differences in chromosomes and link these to a phenotypic trait. At the time, it was commonly thought that biological sex was determined either by the mother or other environmental factors. In fact, Stevens’s findings directly refuted the previous idea of Clarence Erwin McClung, who argued that the X chromosome determined biological sex. Around the same time as Stevens’s findings, Edmund Wilson made a similar discovery while studying spermatogenesis. However, Wilson’s research only examined male and not female germ cells. Additionally, Stevens’s work was based on Mendelian theory and, although Wilson obtained similar results, his findings deviated from this theory.  

     Although Stevens’s findings were momentous, they were not appreciated during the time and did not receive the attention they deserved until 1933, when genetics became a more popular field of study. Additionally, as a woman scientist, her findings were not taken seriously, and she was often overshadowed by her male colleagues. For example, while both Morgan and Wilson were invited to be speakers at a conference to discuss their ideas on sex determination, Stevens was not. In addition, many textbooks credit Stevens’s findings to McClung, Morgan, or Wilson. Interestingly, at the time Stevens published her findings, Morgan disagreed with the conclusions.  

     After her postdoc and findings in sex determination, Stevens got a job at Bryn Mawr College and eventually became an Associate in Experimental Morphology. In 1912, nine years after receiving her PhD, she was finally offered her dream job as a research professor at Bryn Mawr College. Unfortunately, she passed away from breast cancer before she could accept the offer. Although Stevens’s time as a scientist was cut short, she left an outstanding legacy, publishing 38 papers during her time as a scientist.  

     Although Stevens’s accomplishments were not appreciated while she was alive, her success has been celebrated more recently. For example, she was inducted into the National Women’s Hall of Fame in 1994, was the center of a Google Doodle to celebrate her 155th birthday in 2016, and had a Science and Innovation Center named after her at Westfield State University. Nettie Stevens was determined to become a scientist, and no matter how difficult her journey was, she became a legendary one.  



Nettie Stevens | American biologist and geneticist | Britannica. (2020). In Encyclopædia Britannica.

Nettie Stevens: Biography and Contributions - science - 2022. (n.d.). Warbletoncouncil. Retrieved September 6, 2022, from

Nettie Stevens: A Discoverer of Sex Chromosomes | Learn Science at Scitable. (2014).

Dr. Esther Lederberg

August, 2022 by Afrida Rahman-Enyart, PhD

This month’s “Scientist Spotlight” features microbiologist Dr. Esther Lederberg. Dr. Lederberg is best known for her pioneering work in bacterial genetics. Her work led to the discovery of the lambda phage, a bacteriophage used to study gene expression and genetic recombination. Lederberg also developed the replica plating technique, allowing for the analysis of bacterial mutant viability, and tracking of antibiotic resistance.   

      Esther Lederberg (maiden name: Zimmer) was born in 1922 in the Bronx, New York. Growing up in a modest household during the Great Depression, Lederberg often ate a piece of bread with tomato juice for lunch. At a young age, she showed proficiency for schooling and earned a scholarship to attend Hunter College. Against the advice of her teachers, who were worried about a woman succeeding in the sciences, Lederberg decided to major in biochemistry and genetics. In 1942, she graduated cum laude and continued a path in genetics.

     Following graduation from Hunter College, Lederberg worked as a research assistant at what is currently Cold Spring Harbor Laboratory and did a fellowship at Stanford University. While at Stanford, Lederberg expanded her knowledge of genetics and eventually entered a master’s program. The year she completed her master’s degree, Esther married Joshua Lederberg. The couple moved first to Yale and then to the University of Wisconsin. Esther Lederberg first worked as an unpaid research associate in her husband’s lab at the University of Wisconsin but then pursued her doctorate degree where she studied genetic mutations in E. coli.

      While doing her PhD in 1950, Lederberg first isolated lambda phage while working with mutagenized E. coli. She noticed stagnant and aberrant growth in different colonies of the bacteria E. coli K-12 after being exposed to ultraviolet light. Upon further examination, she discovered that this was due to a dormant virus that became active in some mutants. Lederberg further revealed that lambda phage was a unique virus. Instead of only multiplying inside the host like other viruses, lambda phage also integrated its DNA into the host resulting in new generations of bacteria with the virus. The virus remained dormant unless the bacterium was exposed to stress. Lambda phage is still utilized today to study genetic recombination and genetic engineering. Clinically, lambda phage is being explored as a treatment for bacterial infections as an alternative to antibiotics.

     In 1951, Lederberg, in collaboration with her husband, invented the replica plating technique. To perform this technique, Lederberg took a plate with bacterial colonies and made an imprint of the colonies by pressing them onto sterile velvet. The velvet was then used to stamp the colonies onto other agar plates spiked with different added supplements. Therefore, bacterial colonies were replicated on different agar plates with the same spatial configuration. This allowed for a comparison of the effects of environmental change on bacterial health. Prior to this method, scientists had used toothpicks, paper, wire brushes, and multipronged inoculators to perform a similar but less effective technique. Lederberg used this technique to first show that bacteria spontaneously developed antibiotic resistance. Replica plating is still used today to study the effects of colony formation in response to the presence or absence of different antibiotics or nutrient supplements.  

      Although Lederberg was an outstanding scientist, she struggled to gain recognition or secure an academic position due to the discrimination against women scientists at the time. Her husband, however, became the head of genetics at Stanford University and he was mainly credited for the findings in lambda phage and the replica plating technique. In 1958, Joshua Lederberg won the Nobel Prize and Esther Lederberg was viewed as the wife of the Nobel laureate, as opposed to an independent scientist and collaborator. After complaining to the dean over the lack of women professors at Stanford, Lederberg was finally hired as an untenured associate professor, even though she was overqualified for the job. She was never offered a tenured position and had to fight to keep her job after she and Joshua Lederberg divorced. Even though Esther Lederberg made monumental contributions to bacterial genetics, she was excluded from writing a chapter in the book Phage and the Origins of Molecular Biology and many textbooks often ignore her work and give credit to only her husband. Esther Lederberg was a phenomenal scientist who unfortunately did not receive the recognition that she deserved. However, her perseverance and inquisitive nature make her an iconic role model for all women in science.   


Esther Lederberg, pioneer in genetics, dies at 83. (2006). Stanford University.

Iozzio, C., & Zeldovich, L. (2022, May 23). Esther Lederberg changed our understanding of how bacteria breed. Popular Science.

Marks. (2015). Professor Esther Lederberg | Biographical summary. WhatisBiotechnology.Org.

Mayborn, T. (2021, December 10). Esther Lederberg: A Forgotten Genius - Young Spurs. Medium.

Dr. Ben Barres

July, 2022 by Afrida Rahman-Enyart, PhD

“I lived life on my terms: I wanted to switch genders, and I did. I wanted to be a scientist, and I was. I wanted to study glia, and I did that too. I stood up for what I believed in and I like to think I made an impact, or at least opened the door for the impact to occur. I have zero regrets and I’m ready to die. I’ve truly had a great life.” – Dr. Ben Barres reflecting on his life after his diagnosis of pancreatic cancer.

     The “Scientist Spotlight” for this month features neurobiologist Dr. Ben A. Barres. Dr. Barres is best known for his work studying the interactions between glial cells and neurons, including his findings on glial-dependent synapse elimination and myelin formation. After transitioning to male in 1997, Barres also prominently spoke and wrote about sexism in the sciences.     

     Barres was born in 1954 in West Orange, New Jersey as Barbara A. Barres. Even though he was assigned female at birth, Barres knew at a very young age that he was a boy. While growing up, Barres was immediately drawn to and excelled at math and science. Barres would request to be placed in science and engineering courses at school but, being female, was continuously denied access. Eventually, Barres was able to enroll in a summer science program at Columbia University that had no gender restrictions. This program gave Barres the resources he needed to pursue a career in science.

     Barres received his undergraduate degree in Biology from Massachusetts Institute of Technology (MIT). While at MIT, still as Barbara, Barres was continuously subjected to gender discrimination. In one instance, after solving a difficult math problem, Barres’ professor, not believing that Barres had outshone his male classmates, accused Barres of having his boyfriend solve the problem for him. Barres was also consistently at the top of his class but had difficulties securing a research supervisor. Nonetheless, he outperformed many of his peers and followed the path toward an MD at Dartmouth College. While doing his residency at Weill Cornell Medicine, Barres developed an interest in studying neurodegeneration and its correlation with aberrant glial cells. This topic interested him so much that he left his residency to pursue his PhD in neurobiology at Harvard Medical School. His graduate studies focused on the organization and function of cation channels in glial cells. After completing his PhD, Barres was a postdoctoral fellow at University College London where he discovered that developing neurons communicate with oligodendrocytes to myelinate neuronal axons.

     In 1993, as Barbara, Barres started his own lab at Stanford University. Barres’ work ethic and mentorship have been described as “legendarily intense” by his colleague Dr. Andrew Huberman. Barres was known to have three-hour-long lab meetings and oftentimes worked 18–20-hour days. He provided great leadership for his students and postdocs, allowed them creative scientific freedom, and supported diverse collaborations. Barres viewed his lab as his family and was immensely devoted to his research. During his time at Stanford, the Barres Lab made several monumental discoveries, including understanding the roles of astrocytes and microglia in synapse elimination and studying signaling pathways that modulate neuronal survival, neuronal regeneration, and maintenance of the blood–brain barrier.     

     In 1997, Barres transitioned to male and started going by Ben. Therefore, many of his earlier publications were written under the name Barbara. In his book “The Autobiography of a Transgender Scientist,” Barres recollects his experiences of gender discrimination prior to transitioning. For example, after giving his first seminar as Ben Barres at the Whitehead Institute for Biomedical Research, a scientist commented: “Ben Barres gave a great seminar today, but his work is much better than his sister’s.” Barres, in fact, did not have a sister in science and the commenter was referring to Barres’ work while he was Barbara. Barres noticed that after transitioning, people were not aware that he was transgendered, and he felt that he received more respect as a man than when he presented himself as a woman. Barres’ experiences pre- and post-transition motivated him to become an advocate for gender equality in the sciences. He frequently wrote and spoke about his experiences, even calling out an economist who claimed that women have lower levels of “intrinsic aptitude,” resulting in fewer women in science and engineering. Barres’ views on gender issues in the sciences were also featured in an article in The Wall Street Journal in 2006.

     In 2008, Barres was appointed Chair of Neurobiology at Stanford University and in 2013 became the first openly transgender scientist in the National Academy of Sciences. Unfortunately, in April of 2016, Barres was diagnosed with advanced pancreatic cancer. His prognosis did not stop his devotion to his research, and even amidst treatment, he continued to write manuscripts, applications for grants, and even future letters of support for his students to use after his passing. In 2017 Barres passed away from pancreatic cancer. Prior to his death, Barres reflected that he had done everything in his life that he sought to do. Sure enough, Dr. Barres not only made a lasting impact in the field of neuroscience but also inspired an entire generation of neuroscientists.      


Barres, B., & Hopkins, N. (2020). The Autobiography of a Transgender Scientist (Mit Press). The MIT Press.


Begley, S. (2006, July 13). He, Once a She, Offers Own View On Science Spat. WSJ.


Does Gender Matter? by Ben A Barres | Learn Science at Scitable. (2006, July). Scitable by Nature Education.


Huberman, A. (2018, January 11). Ben Barres (1954–2017). Nature.

Scientist Spotlight 

June, 2022 by Afrida Rahman-Enyart, PhD.

This month’s “Scientist Spotlight” features chemist Dr. Percy Lavon Julian. Julian is known for his seminal work in studying the chemical synthesis of medicinal drugs from plants. His work was the principle for the bulk production of sex hormones, cortisone, and other corticosteroids.

Julian was born in Montgomery, Alabama in 1899 and was the eldest of six children. His father worked as a post office clerk and his mother was a schoolteacher. Julian’s extended family had faced immense hardships in the past, including his paternal grandfather, who had been a slave.  

During the early 1900s, high school education was extremely rare for African Americans. Although Julian did attend high school, the education and resources at his school were lacking. Consequently, Julian was accepted as a “sub-freshman” at DePauw University, taking both high school and freshman-level classes simultaneously. DePauw was quite segregated at the time and Julian was forbidden from living in the college dormitory. Instead, he stayed in a boarding home that refused to provide him with meals. He was eventually allowed to live in a fraternity house attic in exchange for doing odd jobs around the house. Yet despite his initial academic struggles and having suffered constant discrimination, Julian graduated in 1920 with a degree in chemistry and as the valedictorian of his class.

After being denied entrance into PhD programs, Julian went on to teach chemistry at Fisk University. After a few years, he was awarded an Austin Fellowship in Chemistry and was able to enroll in the organic chemistry master’s program at Harvard University. At Harvard, however, Julian was stripped of his teaching assistantship as university officials were worried that white students might react negatively to being taught by an African American instructor. After attending Harvard, Julian continued to teach at West Virginia State College and Howard University.

Julian eventually received a Rockefeller Foundation fellowship, which allowed him to pursue his PhD in chemistry at the University of Vienna. This transition from the USA to Austria would be pivotal for Julian’s career. While at the University of Vienna, Julian was able to participate in social gatherings, was accepted by his colleagues, and became one of the first African Americans to receive a PhD in chemistry.   

After receiving his PhD, Julian returned to the US to teach first at Howard University and then at DePauw University. However, he was denied a professorship and consistently had issues securing employment for racial reasons. While at DePauw, Julian and his colleague Josef Pikl completed the first total synthesis of physostigmine, an alkaloid found in the Calabar bean and used to treat glaucoma. During this process, Julian noticed the steroid stigmasterol as a by-product of physostigmine synthesis. This discovery would be the catalyst for Julian’s groundbreaking work.

Around the time that Julian and Pikl were working on physostigmine, other researchers were seeking cheaper and more efficient ways to synthesize steroids, such as cortisone and sex hormones. At the time, only small quantities of sex hormones could be extracted from a large amount of animal spinal cords. It was discovered that stigmasterol could be used to synthesize sex hormones. In addition to being a product of the Calabar bean, stigmasterol was a product of soybean. Therefore, Julian reached out to the soybean oil company Glidden and requested several gallons of oil to initiate experiments for synthesizing human sex hormones. Interestingly, after Julian requested the soybean oil, the vice-president of the company hired him as the director of research in the Soya Division in Chicago, IL. There, Julian invented several soy-based products including Aero-Foam, which was utilized in World War II to put out oil and gas fires.

While conducting his research at Glidden, Julian made a serendipitous discovery when water mistakenly leaked into a container of soybean oil. He observed that the water led to the formation of a white mass in the oil and identified it as stigmasterol. Julian realized that he had just found a method for producing the large amounts of the steroid needed to synthesize progesterone, estrogen, and testosterone from soybeans. Julian’s patented technique was known as a “foam technique” and enabled the development of an industrial method to produce sex hormones on a large scale.

After Julian’s work in the bulk production of sex hormones, Mayo Clinic shared the discovery that cortisone had substantial benefits for rheumatoid arthritis. Upon learning this, Julian began to seek a way to synthesize large amounts of cortisone inexpensively. He was able to use the soy product pregnenolone and synthesize Substance S, which differed from cortisone by one oxygen atom. In 1953, Pfizer used Julian’s findings and developed a fermentation process to convert Substance S directly to hydrocortisone.

After his time at Glidden, Julian and his family moved to Oak Park, IL. They became the first African American family to live there. Although some of their neighbors welcomed the diversity, many others were quite upset. Julian’s family home was the target of firebombing and attacks with dynamite, which resulted in him guarding his property with a shotgun.

In 1954, Julian started his own company called Julian Laboratories and endeavored to hire all the top African American and women chemists. He also became an advocate of groups seeking to improve conditions for African Americans and was a founder of the Legal Defense and Educational Fund of Chicago.

Percy Lavon Julian grew up in a nation where he was constantly discriminated against, but his uplifting story shows us that no one could stop his love for science.       



(2021, April 16). Percy Julian. Biography.

The Life of Percy Lavon Julian ’20. (2009). DePauw University.

Percy Lavon Julian. (1999). American Chemical Society.

Percy Lavon Julian. (2020, October 15). Science History Institute.


Dr. Helen B. Taussig 

May, 2022 by Afrida Rahman-Enyart, PhD.

This month’s “Scientist Spotlight” is on cardiologist Dr. Helen B. Taussig. Taussig is credited as the founder of the field of pediatric cardiology after her work on babies born with anoxemia, or “blue baby” syndrome. “Blue baby” syndrome is caused by a lack of oxygen in the blood, resulting in a blue tint to the baby’s skin. It can arise due to congenital heart defects or environmental factors. A severe congenital heart condition that causes “blue baby” syndrome is Tetralogy of Fallot (TOF), a defect consisting of four cardiac abnormalities. The pioneering work of Taussig and her colleagues resulted in a procedure that prolonged the lives of infants suffering from TOF, and a modified version is still used today. Taussig’s road to becoming a life-saving physician is inspirational for everyone, especially aspiring women in science.

Taussig was born in 1898 in Cambridge, Massachusetts and she quickly became familiar with adversity. As a child, Taussig suffered from an ear infection causing partial hearing loss, which later progressed, leaving her fully deaf as an adult. In addition, she struggled with severe dyslexia early on in her education. Taussig also contracted tuberculosis, the same ailment her mother succumbed to, and was ill for several years. Understandably, these hardships made her early school days difficult. However, with her father’s extensive tutoring and her innate determination to excel, Taussig did quite well in school. She went on to receive her undergraduate degree from the University of California-Berkeley.

Taussig’s challenging journey, however, did not end there. After receiving her BA, she aspired to go to Harvard Medical School. At that time, Harvard did not award degrees to women. Taussig had a similar experience when attempting to enroll at Boston University. She was allowed to attend biology courses with the understanding that she would not receive a degree and could not sit near or interact with her male classmates. Taussig eventually transferred to Johns Hopkins University where she was able to rightfully obtain her MD. She remained loyal to the university for the rest of her career and became the first woman at Johns Hopkins to hold a full professorship.

It was at Johns Hopkins where Taussig, Alfred Blalock, and Vivien Thomas developed the procedure that would help countless babies suffering from TOF. By this time, Taussig fully relied on hearing aids and lip-reading. She would use an amplified stethoscope or her hands to feel any discrepancies in the rhythm of infant heartbeats. Through observations of several types of heart defects in babies, Taussig realized that those suffering from TOF had a lack of blood flow to the lungs. These findings spearheaded the development of the Blalock-Thomas-Taussig shunt. The shunt connected the subclavian or carotid artery to the pulmonary artery, allowing for the blood to become oxygenated. Taussig and her colleagues tested the experimental procedure in dogs and then successfully in a handful of patients. The Blalock-Thomas-Taussig shunt is still often used in babies with TOF prior to performing more complex open-heart surgeries.

Later in her career, Taussig was a key leader in the campaign to ban FDA approval of thalidomide to treat morning sickness for pregnant women after it was linked to birth defects. As women’s rights became more prominent, Taussig’s work was recognized, and she received many honors for her accomplishments. In 1965, she became the first woman president of the American Heart Association. Taussig lived an inspirational life, fighting through every obstacle thrown her way, in order to save the lives of others. Click here to read more about Dr. Helen B. Taussig.  



Forde, R. J. (n.d.). Helen Brooke Taussig. Jewish Women's Archive. Retrieved April 15, 2022, from

Goodman, G. L. (1983). A gentle heart: the life of Helen Taussig.

National Institutes of Health (2015, June 3). Changing the face of Medicine | Helen Brooke Taussig. U.S. National Library of Medicine. Retrieved April 15, 2022, from

Spindler, L. (2020, April 21). Helen B. Taussig, MD: A pioneer in the diagnosis and treatment of congenital heart disease. The Women in Medicine Legacy Foundation. Retrieved April 15, 2022, from


Dr. Har Gobind Khorana

April, 2022 by Afrida Rahman-Enyart, PhD.

In honor of DNA Day and the observed 100th birthday of the pioneering biochemist who uncovered the genetic code, our first “Scientist Spotlight” focuses on Dr. Har Gobind Khorana (image, left). In 1968, along with Marshall W. Nirenberg and Robert W. Holley, Khorana won the Nobel Prize in Physiology or Medicine for the groundbreaking discovery that connected DNA to protein synthesis.  

 However, Khorana’s arduous journey that led him to becoming a Nobel Prize-winning scientist makes his story even more inspiring. Khorana battled poverty at a young age, not even owning a pencil until age 6 and getting his initial years of schooling under a tree. Persevering through these hardships, Khorana went on to receive his PhD in organic chemistry from the University of Liverpool in 1948. Khorana eventually secured a fellowship at University of Cambridge where he used the chemical N,N’-Dicyclohexylcarbodiimide (DCC) to assemble and dissemble strings of amino acids and nucleotides. From there, Khorana established his own laboratory, first at the University of British Columbia and then moving to the University of Wisconsin-Madison. Khorana continued utilizing DCC to synthesize DNA sequences and eventually introduced them to cellular elements which translated the DNA into amino acids and partial proteins. These findings were monumental as they gave rise to our understanding of codons and how the order of nucleotides controls protein synthesis. Khorana continued his research and eventually created the first synthetic gene.    

Although Khorana’s work was groundbreaking, racism obstructed his recognition, and he was often neglected by authors and interviewers. Khorana also faced racial slurs against himself and his mixed-race family throughout his career and suffered from discrimination at work where he was paid less than his white colleagues. Khorana’s determination and dedication led him on a path to becoming one of the most influential biochemists, and it is finally time to celebrate all his achievements. Click here to read more about Dr. Har Gobind Khorana.    


  1. Gobind Khorana – Biographical - Retrieved April 11, 2022, from
  2. Sarkar, S. (2022, April 7). Remembering Har Gobind Khorana, the chemist who overcame poverty to win the nobel prize Retrieved April 11, 2022, from