Embryo Project Encyclopedia Articles

The Spemann-Mangold organizer, also known as the Spemann organizer, is a cluster of cells in the developing embryo of an amphibian that induces development of the central nervous system. Hilde Mangold was a PhD candidate who conducted the organizer experiment in 1921 under the direction of her graduate advisor, Hans Spemann, at the University of Freiburg in Freiburg, German. The discovery of the Spemann-Mangold organizer introduced the concept of induction in embryonic development. Now integral to the field of developmental biology, induction is the process by which the identity of certain cells influences the developmental fate of surrounding cells. Spemann received the Nobel Prize in Medicine in 1935 for his work in describing the process of induction in amphibians. The Spemann-Mangold organizer drew the attention of embryologists, and it spurred numerous experiments on the nature of induction in many types of developing embryos.

In 'Altruism and the Origin of the Worker Caste,' Bert Hölldobler and Edward Osborne Wilson explore the evolutionary origins of worker ants. 'Altruism and the Origin of the Worker Caste' is the fourth chapter of Hölldobler and Wilson's book, The Ants, which was published by The Belknap Press of Harvard University in Cambridge, Massachusetts, in 1990. In 'Altruism and the Origin of the Worker Caste,' Hölldobler and Wilson evaluate various explanations for how a non-reproductive caste of ant evolved. Their investigation into the evolutionary origins of worker ants synthesized research on the reproductive practices of ants to provide an analysis of how sterile groups of organisms persist in a population.

Between 1925 and 1961, a Roman Catholic order of nuns called the Bon Secours Sisters operated the Bon Secours Mother and Baby Home, or the Home, an institution where unmarried pregnant women gave birth in Tuam, Ireland. Pregnant women who delivered their infants at the Home were required to work at the Home for no less than one year without pay. The Irish government and the Catholic Church endorsed the Mother and Baby Home as a means to limit the number of children born out of wedlock by discouraging women from getting pregnant before marriage. During the Home’s thirty-six years of operation, the nuns reported that almost 800 children died in their care. In 2015, researchers discovered a tomb of 796 infant and child skeletons in a septic tank underneath where the Home once stood. The acceptance and use of Mother and Baby Homes revealed the way Ireland treated pregnant women in the twentieth century.

In the 2007 paper “Traditional postpartum practices and rituals: a qualitative systematic review,” Toronto-based researchers showed that women from different cultures around the world follow similar postpartum practices after giving birth. At the University of Toronto in Toronto, Canada, Cindy-Lee Dennis, Kenneth Fung, Sophie Grigoriadis, Gail Erlick Robinson, Sarah Romans, and Lori Ross examined fifty-one studies from over twenty countries that focused on traditional postpartum practices. The authors found that across the twenty countries, each culture’s postpartum practice included a specified rest period, a prescribed diet, and organized support from family members. In the literature review, Dennis and her team concluded that healthcare providers should consider the major similarities between cultural postpartum practices to deliver culturally competent perinatal care.

Self-proclaimed female physician Ann Trow was a women’s reproductive health specialist as well as an abortion provider in New York City, New York during the mid 1800s. Though she had no formal medical training or background, Trow provided women with healthcare and abortions under the alias Madame Restell. Restell gained attention across the United States for her career as a professional abortionist during a time when abortions were highly regulated and punishable with imprisonment. Restell was tried numerous times for carrying out abortions. She never confessed to any crimes, but she was convicted on several occasions. Her services as a business woman, medicine producer, abortion provider, boarding house maintainer, and adoption facilitator provided women with solutions to unwanted pregnancies throughout her forty years of healthcare service and made her a subject of widespread controversy in the United States.

In the twentieth and early twenty-first centuries, Gail Roberta Martin specialized in biochemistry and embryology, more specifically cellular communication and the development of organs. In 1981, she named any cell taken from inside a human embryo at the blastocyst stage an “embryonic stem cell”. During development, an embryo goes through the blastocyst stage just before it implants in the uterus. Embryonic stem cells are useful for experiments because they are self-renewing and able to develop into almost any cell type in the body. Martin later identified a key chemical component in limb development and continues to study embryogenesis, or the growth of embryos over time. Martin’s work on embryonic stem cells has allowed scientists to further research and treat human diseases, and her study of how organs form has helped scientists learn about the healthy growth of embryos.

Mary-Claire King studied genetics in the US in the twenty-first century. King identified two genes associated with the occurrence of breast cancer, breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2). King showed that mutated BRCA1 and BRCA2 genes cause two types of reproductive cancer, breast and ovarian cancer. Because of King’s discovery, doctors can screen women for the inheritance of mutated BRCA1 and BRCA2 genes to evaluate their risks for breast and ovarian cancer. King also demonstrated the genetic similarities between chimpanzees and humans and helped to identify victims of human rights abuses using genetics. King's identification of the BRCA genes and their relationship to breast and ovarian cancer, both reproductive cancers, has allowed physicians to screen thousands of women for the genes and for those women to choose to undergo preventative cancer treatment to lower their risk of cancer.

Berthold Karl Hölldobler studied social insects like ants in Europe and the US during the twentieth and early twenty-first century. He focused on the social behavior of ants, the evolutionary origins of social insects, and the way ants use chemicals to communicate with each other. Hölldobler’s research reached popular audiences through his co-authored Pulitzer Prize winning book The Ants and through an award winning nature documentary called Ameisen: Die heimliche Weltmacht (Ants: Nature’s Secret Power). Hölldobler researched reproductive practices in specific ant species and helped explain how reproductive practices influence, and are influenced by, social behaviors.

Friedrich Tiedemann studied the anatomy of humans and animals in the nineteenth century in Germany. He published on zoological subjects, on the heart of fish, the anatomy of amphibians and echinoderms, and the lymphatic and respiratory system in birds. In addition to his zoological anatomy, Tiedemann, working with the chemist Leopold Gmelin, published about how the digestive system functioned. Towards the end of his career Tiedemann published a comparative anatomy of the brains of white Europeans, black Africans, and Orangutans, in which he argued that there were no appreciable differences between the structure of the brains of blacks, women, and white European men that would suggest they were intellectually different. Tiedemann also researched the embryonic development of the brain and circulatory systems of human fetuses.

Neonatal respiratory distress syndrome, previously called hyaline membrane disease, is a respiratory disease affecting premature newborns. Neonatal respiratory distress syndrome involves shallow breathing, pauses between breaths that last a few seconds, or apnea, and a bluish tinge to the infant’s skin. The syndrome occurs when microscopic sacs called alveoli in infant lungs do not produce surfactant, a liquid that coats the inside of the lungs and helps them inflate during breathing. Respiratory distress syndrome is the leading cause of death among premature infants and, in rare cases, it can affect full-term infants. Physicians can administer artificial, animal-derived surfactant to treat respiratory distress syndrome. As of 2017, the treatment has decreased the mortality rate of respiratory distress syndrome from almost one hundred percent to less than ten percent.