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Peter Mazur (1928–2015)
Peter Mazur was a researcher in the US who developed new ways of preserving biological material by freezing it, a process called cryopreservation. If done correctly, cryopreservation enables scientists to store or study biological material for an extended period of time. If done incorrectly, cryopreservation can easily harm or destroy biological material. Mazur worked to find the best ways to cryopreserve different cells, embryos, and organs in order to minimize the damage caused by freezing.
Format: Articles
Subject: People
Ernest John Christopher Polge (1926-2006)
Twentieth-century researcher Ernest John Christopher Polge studied the reproductive processes of livestock and determined a method to successfully freeze, thaw, and utilize viable sperm cells to produce offspring in animals. In 1949, Polge identified glycerol as a cryoprotectant, or a medium that enables cells to freeze without damaging their cellular components or functions. Several years later, Polge used glycerol in a freezing process called vitrification, which enabled him to freeze poultry sperm, thaw that sperm, and use it to fertilize vertebrate embryos.
Format: Articles
Subject: People
William Thornton Mustard (1914-1987)
William Thornton Mustard was a surgeon in Canada during the twentieth century who developed surgical techniques to treat children who had congenital heart defects. Mustard has two surgeries named after him, both of which he helped to develop. The first of these surgeries replaces damaged or paralyzed muscles in individuals who have polio, a virus that can cause paralysis. The other technique corrects a condition called the transposition of the great arteries (TGA) that is noticed at birth.
Format: Articles
Matthew Stanley Meselson (1930– )
Matthew Stanley Meselson conducted DNA and RNA research in the US during the twentieth and twenty-first centuries. He also influenced US policy regarding the use of chemical and biological weapons. Meselson and his colleague Franklin Stahl demonstrated that DNA replication is semi-conservative. Semi-conservative replication means that every newly replicated DNA double helix, which consists of two individual DNA strands wound together, contains one strand that was conserved from a parent double helix and that served as a template for the other strand.
Format: Articles
Subject: People
Andrew Francis Dixon (1868-1936)
Andrew Francis Dixon studied human anatomy and egg cells at the turn of the twentieth century in Ireland and Great Britain. Dixon studied the sensory and motor nervous system of the face, the cancellous bone tissue of the femur, supernumerary kidneys, and the urogenital system. In 1927 Dixon described a mature human ovarian follicle. This follicle, Dixon noted, contained an immature human egg cell (oocyte) with a visible first polar body and the beginnings of the second polar body.
Format: Articles
Subject: People
John Philip Trinkaus (1918-2003)
John Philip Trinkaus studied the processes of cell migration and gastrulation, especially in teleost fish, in the US during the twentieth century. Called Trink by his friends, his social confidence and work ethic combined to make him a prolific and decorated developmental biologist. His scientific contributions included investigations of several different aspects of embryology.
Format: Articles
Subject: People
George Nicholas Papanicolaou (1883–1962)
George Nicholas Papanicolaou developed the Pap test in the United States during the twentieth century. The Pap test is a diagnostic procedure used to test for cervical cancer in women. Papanicolaou’s work helped improve the reproductive health of women by providing an effective means of identifying precancerous cells and improving the likelihood of early treatment and survival of cervical cancer.
Format: Articles
Subject: People, Reproduction
Nettie Maria Stevens (1861-1912)
Multiple theories about what determines sex were tested at the turn of the twentieth century. By experimenting on germ cells, cytologist Nettie Maria Stevens collected evidence to support the connection between heredity and the sex of offspring. Stevens was able to interpret her data to conclude that chromosomes have a role in sex determination during development. For her time, she was an emerging breed: a woman of science making the leap from the world of data collection to that of male-dominated interpretive work.
Format: Articles
Subject: People, Reproduction
John Craig Venter (1946- )
John Craig Venter helped map the genomes of humans, fruitflies, and other organisms in the US in the late 1990s and early 2000s, and he helped develop an organism with a synthetic genome. In February 2001, Venter and his team published a human genome sequence after using a technique known as Expressed Sequence Tags, or ESTs. Venter worked to bridge commercial investment with scientific research. Venter founded a number of private companies, including the for-profit Celera Genomics, headquartered in Alameda, California, as well as research institutes, such as the not-for-profit J.
Format: Articles
Subject: People
Edwin Carlyle (Carl) Wood (1929–2011)
Edwin Carlyle Wood, also known as Carl Wood, was a physician who helped develop in vitro fertilization, or IVF, treatments. From 1964 to 1992, Wood worked as a professor of obstetrics and gynecology at Monash University in Melbourne, Australia, where he was one of the first in the world to lead a team of physicians to establish IVF as a proven treatment for infertility. IVF refers to a medical procedure in which scientists inseminate an egg cell with a sperm cell outside of the body, such as in a glass dish in a clinical setting.
Format: Articles
Subject: People, Technologies, Reproduction
The Case of Lydia Fairchild and Her Chimerism (2002)
In 2002, after applying for government assistance in the state of Washington, Lydia Fairchild was told that her two children were not a genetic match with her and that therefore, biologically, she could not be their mother. Researchers later determined that the genetic mismatch was due to chimerism, a condition in which two genetically distinct cell lines are present in one body. The state accused Fairchild of fraud and filed a lawsuit against her.
Format: Articles
John George Children (1777–1852)
John George Children described several species of insects and animals while working at the British Museum in London, England, in the eighteenth and nineteenth centuries. Children also conducted research on chemical batteries called voltaic cells and briefly studied and manufactured gunpowder. One of the species he described, the Children’s python, or Antaresia children, was used in the twenty-first century as the subject of experiments that involved the biological cost of reproduction in snakes.
Format: Articles
Subject: People
Kurt Benirschke (1924-)
Kurt Benirschke studied cells, placentas, and endangered species in Germany and the US during the twentieth century. Benirschke was professor at the University of California in San Diego, California, and a director of the research department at the San Diego Zoo in San Diego, California. He also helped form the research department of the San Diego Zoo and its sister organization, the Center for Reproduction of Endangered Species.
Format: Articles
Subject: People
Brian K. Hall (1941- )
Brian Hall is the son of Doris Garrad and Harry Hall, and was born in Port Kembla, NSW Australia, on 28 October 1941. He attended the University of New England in Armidale NSW, graduating in 1963 with a BSc in zoology, in 1965 with a BSc (Honors) in zoology, and in 1968 with a PhD in zoology. His PhD thesis, undertaken under the supervision of Patrick D. F. Murray, FAA was on the differentiation of bone and secondary cartilage in chicken embryos.
Format: Articles
Subject: People
Julia Barlow Platt (1857-1935)
Julia Barlow Platt studied neural crests in animal embryos and became involved in politics in the US during the nineteenth and twentieth centuries. She researched how body and head segments formed in chicks (Gallus gallus) and spiny dogfish (Squalus acanthias). Platt observed that in the mudpuppy (Necturus maculosus), the coordinated migration of neural crest cells in the embryo produced parts of the nervous system, bones, and connective tissues in the head.
Format: Articles
Subject: People
Leonard Colebrook (1883–1967)
Leonard Colebrook was a physician who researched bacteria and infections in England during the twentieth century. In 1936, Colebrook deployed the antibiotic Prontosil to treat puerperal fever, a disorder that results from bacterial infections in the uterine tracts of women after childbirth or abortions. Colebrook also advanced care for burn patients by advocating for the creation of burn units in hospitals and by using antisepsis medication for burn wound infections. Colebrook’s work on treatments for puerperal fever reduced cases of puerperal fever throughout the world.
Format: Articles
Subject: People
David Baltimore (1938– )
David Baltimore studied viruses and the immune system in the US during the twentieth century. In 1975, Baltimore was awarded the Nobel Prize in Physiology or Medicine for discovering reverse transcriptase, the enzyme used to transfer information from RNA to DNA. The discovery of reverse transcriptase contradicted the central dogma of biology at the time, which stated that the transfer of information was unidirectional from DNA, RNA, to protein.
Format: Articles
Subject: People
Roger Wolcott Sperry (1913–1994)
Roger Wolcott Sperry studied the function of the nervous system in the US during the twentieth century. He studied split-brain patterns in cats and humans that result from separating the two hemispheres of the brain by cutting the corpus callosum, the bridge between the two hemispheres of the brain. He found that separating the corpus callosum the two hemispheres of the brain could not communicate and they performed functions as if the other hemisphere did not exist. Sperry studied optic nerve regeneration through which he developed the chemoaffinity hypothesis.
Format: Articles
Subject: People
Oliver Allison Ryder III (1946– )
Oliver Allison Ryder studied chromosomal evolution and endangered species in efforts for wildlife conservation and preservation at the San Diego Zoo in San Diego, California. Throughout his career, Ryder studied breeding patterns of endangered species. He collected and preserved cells, tissues, and DNA from endangered and extinct species to store in the San Diego Frozen Zoo, a center for genetic research and development in San Diego, California.
Format: Articles
Subject: People
Nicolaas Hartsoeker (1656-1725)
Nicolaas Hartsoeker, a Dutch astronomer, optics manufacturer, and naturalist, was born 26 March 1656 in Gouda, Netherlands, and died 10 December 1725. His mother was Anna van der Mey and his father was Christiaan Hartsoeker, a prominent evangelical minister. His major contribution to embryology was his observations of human sperm cells, which he claimed to be the first to see under a microscope. His sketch of the homunculus, a tiny preformed human he believed to exist in the head of spermatazoa, is his lasting scientific legacy in the field of embryology.
Format: Articles
Subject: People
Wilhelm August Oscar Hertwig (1849-1922)
Wilhelm August Oscar Hertwig contributed to embryology through his studies of cells in development and his discovery that only one spermatozoon is necessary to fertilize an egg. He was born 21 April 1849 to Elise Trapp and Carl Hertwig in Hessen, Germany. After his brother Richard was born the family moved to Muhlhausen in Thuringen where the boys were educated. The two brothers later attended the university in Jena from 1868 to 1888 and studied under Ernst Haeckel, who later convinced Hertwig to leave chemistry and pursue medicine.
Format: Articles
Subject: People
Ian Hector Frazer (1953– )
Ian Hector Frazer studied the human immune system and vaccines in Brisbane, Australia, and helped invent and patent the scientific process and technology behind what later became the human papillomavirus, or HPV, vaccinations. According to the Centers for Disease Control and Prevention of the US, or CDC, HPV is the most common sexually transmitted infection, and can lead to genital warts, as well as cervical, head, mouth, and neck cancers.
Format: Articles
Subject: People
Alfred Henry Sturtevant (1891–1970)
Alfred Henry Sturtevant studied heredity in fruit flies in the US throughout the twentieth century. From 1910 to 1928, Sturtevant worked in Thomas Hunt Morgan’s research lab in New York City, New York. Sturtevant, Morgan, and other researchers established that chromosomes play a role in the inheritance of traits. In 1913, as an undergraduate, Sturtevant created one of the earliest genetic maps of a fruit fly chromosome, which showed the relative positions of genes along the chromosome.
Format: Articles
Subject: People
Hans Spemann (1869-1941)
Hans Spemann was an experimental embryologist best known for his transplantation studies and as the originator of the "organizer" concept. One of his earliest experiments involved constricting the blastomeres of a fertilized salamander egg with a noose of fine baby hair, resulting in a partially double embryo with two heads and one tail.
Format: Articles
Subject: People
Arthur Earl Walker (1907-1995)
Arthur Earl Walker was a medical researcher and physician who studied the brain and neurosurgery in the United States during the twentieth century. Walker examined the connections of the thalamus to the rest of the brain and how the thalamus coordinates sensory signals. The thalamus is a cluster of nerve cells located between the two hemispheres of the brain and it is responsible for consciousness and sensory interpretation.
Format: Articles
Subject: People