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Johannes Holtfreter
Johannes Holtfreter (January 9, 1901 – November 13, 1992) was a German-American developmental biologist whose primary focus was the “organizer,” a part of the embryo essential for the development of the proper body plan. Biography Holtfreter was born on January 9, 1901, in Richtenberg, Pomerania, Germany, as the only son and second out of three children. As a child, he captured animals (including butterflies) and made drawings of them, and after graduating from the Realgymnasium, he wanted to enter field biology. Upon beginning this path at the University of Rostock and the University of Leipzig, he eventually moved to the University of Freiburg in order to study under Doflein, a famous naturalist who died soon after Holtfreter transferred. His new thesis advisor was Dr. Hans Spemann, who introduced Holtfreter to his eventual field of study: embryology. After obtaining his Ph.D. in 1924, he eventually entered the field of marine biology at the Stazione Zoologica in Naple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richtenberg, Germany
Richtenberg () is a municipality in the Vorpommern-Rügen district, in Mecklenburg-Western Pomerania, Germany. It is southwest of Stralsund Stralsund (; Swedish: ''Strålsund''), officially the Hanseatic City of Stralsund (German: ''Hansestadt Stralsund''), is the fifth-largest city in the northeastern German federal state of Mecklenburg-Western Pomerania after Rostock, Schwerin, Neub .... Richtenberg was first mentioned in the founding document of the Neuenkamp monastery (today Franzburg) dated 8 November 1231. It is the oldest documented place in the region. In the foundation deed of the ruling Prince Wizlaw I, the monastery was awarded a patronage over the Richtenberg church as well as a local salt source. References Populated places established in the 13th century 1290s establishments in the Holy Roman Empire 1297 establishments in Europe {{VorpommernRügen-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a dictatorship. Under Hitler's rule, Germany quickly became a totalitarian state where nearly all aspects of life were controlled by the government. The Third Reich, meaning "Third Realm" or "Third Empire", alluded to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which Hitler and the Nazis referred to as the Thousand-Year Reich, ended in May 1945 after just 12 years when the Allies defeated Germany, ending World War II in Europe. On 30 January 1933, Hitler was appointed chancellor of Germany, the head of gove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1901 Births
Nineteen or 19 may refer to: * 19 (number), the natural number following 18 and preceding 20 * one of the years 19 BC, AD 19, 1919, 2019 Films * 19 (film), ''19'' (film), a 2001 Japanese film * Nineteen (film), ''Nineteen'' (film), a 1987 science fiction film Music * 19 (band), a Japanese pop music duo Albums * 19 (Adele album), ''19'' (Adele album), 2008 * ''19'', a 2003 album by Alsou * ''19'', a 2006 album by Evan Yo * ''19'', a 2018 album by MHD (rapper), MHD * ''19'', one half of the double album ''63/19'' by Kool A.D. * ''Number Nineteen'', a 1971 album by American jazz pianist Mal Waldron * XIX (EP), ''XIX'' (EP), a 2019 EP by 1the9 Songs * 19 (song), "19" (song), a 1985 song by British musician Paul Hardcastle. * "Nineteen", a song by Bad4Good from the 1992 album ''Refugee (Bad4Good album), Refugee'' * "Nineteen", a song by Karma to Burn from the 2001 album ''Almost Heathen''. * Nineteen (song), "Nineteen" (song), a 2007 song by American singer Billy Ray Cyrus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial animal, terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this. The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to reptiles like lizards but, along with mammals and birds, reptiles are amniotes and do not require water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; in re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viktor Hamburger
Viktor Hamburger (July 9, 1900 – June 12, 2001)Garland E. AllenViktor Hamburger, 1900–2001. National Academy of Sciences Biographical Memoirs, 2015, 39 pp. was a German-American professor and embryologist. His collaboration with neuroscientist Rita Levi-Montalcini resulted in the discovery of nerve growth factor. In 1951 he and Howard Hamilton published a standardized stage series to describe chicken embryo development, now called the Hamburger-Hamilton stages. He was considered "one of the most influential neuroembryologists of the twentieth century". Early life Hamburger was born on in Landeshut, Silesia, Germany to Max Hamburger and Else Gradenwitz. After completing gymnasium in June 1918, Hamburger was inducted into the German army, but was released after the Armistice later that year. The army had discharged him in the city of Breslau, and he began his university studies there, moving to Heidelberg for the academic year of 1919–1920. However, in the spring o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notochord
In anatomy, the notochord is a flexible rod which is similar in structure to the stiffer cartilage. If a species has a notochord at any stage of its life cycle (along with 4 other features), it is, by definition, a chordate. The notochord consists of inner, vacuolated cells covered by fibrous and elastic sheaths, lies along the anteroposterior axis (''front to back''), is usually closer to the dorsal than the ventral surface of the embryo, and is composed of cells derived from the mesoderm. The most commonly cited functions of the notochord are: as a midline tissue that provides directional signals to surrounding tissue during development, as a skeletal (structural) element, and as a vertebral precursor. In lancelets the notochord persists throughout life as the main structural support of the body. In tunicates the notochord is present only in the larval stage, being completely absent in the adult animal. In these invertebrate chordates, the notochord is not vacuolated. In all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holtfreter's Solution
Holtfreter's solution (Holtfreter's medium) is a balanced salt solution that was developed by the developmental biologist Johannes Holtfreter for studying amphibian embryos and to reduce bacterial infections. As a specialised aqueous solution, it finds use in aquaria to prevent infections for early stage amphibians, where it is typically mixed with soft tap water. Amphibians such as axolotls prefer a hard water solution. Composition Molarity Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solut ... of the component salts are as follows: Notes * https://www.msu.edu/user/eisthen/lab/methods/animalcare/holtfr.html ink now dead References * Armstrong, J.B., Duhon, S.T., and Malacinski, G.M. (1989) "Raising the axolotl in captivity". In J. B. Armstrong and G. M. Malacinski (eds.) ''Devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developmental Biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. Perspectives The main processes involved in the embryogenesis, embryonic development of animals are: tissue patterning (via regional specification and patterned cellular differentiation, cell differentiation); tissue growth; and tissue morphogenesis. * Regional specification refers to the processes that create the spatial patterns in a ball or sheet of initially similar cells. This generally involves the action of cytoplasmic determinants, located within parts of the fertilized egg, and of inductive signals emitted from signaling centers in the embryo. The early stages of regional specification do not generate functional differentiated cells, but cell populations committed to developing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curt Stern
Curt Stern (August 30, 1902 – October 23, 1981) was a German-born American geneticist. Life Curt Jacob Stern was born into a middle-class Jewish family in Hamburg, Germany on August 30, 1902. He was the first son of Earned S. Stern, born 1862 in England, who was interned during World War I, and Anna Stern, née Anna Liebrecht who was a schoolteacher (b. 1873). Her father C. Liebrecht was a teacher at the Israelitische Gemeindeschule Gleiwitz, a "Gymnasium" in Upper Silesia, with a PhD in mathematics and natural sciences at the University of Breslau. His father dealt in antiques and dental supplies, and his mother was a schoolteacher.A Guide to the Genetics Collections at the APS.http://www.amphilsoc.org/guides/glass/stern.htm access date 1-3-2014 The family moved to a suburb in Berlin shortly after his birth. As a child, he showed a strong interest in biology and natural history. He went to the "Hindenburgschule" in Berlin-Oberschoeneweide. Supported by two high school te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Rochester
The University of Rochester (U of R, UR, or U of Rochester) is a private research university in Rochester, New York. The university grants undergraduate and graduate degrees, including doctoral and professional degrees. The University of Rochester enrolls approximately 6,800 undergraduates and 5,000 graduate students. Its 158 buildings house over 200 academic majors. According to the National Science Foundation, Rochester spent more than $397 million on research and development in 2020, ranking it 66th in the nation. With approximately 28,000 full-time employees, the university is the largest private employer in Upstate New York and the 7th largest in all of New York State. The College of Arts, Sciences, and Engineering is home to departments and divisions of note. The Institute of Optics was founded in 1929 through a grant from Eastman Kodak and Bausch and Lomb as the first educational program in the US devoted exclusively to optics, awards approximately half ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGill University
McGill University (french: link=no, Université McGill) is an English-language public research university located in Montreal, Quebec, Canada. Founded in 1821 by royal charter granted by King George IV,Frost, Stanley Brice. ''McGill University, Vol. I. For the Advancement of Learning, 1801–1895.'' McGill-Queen's University Press, 1980. the university bears the name of James McGill, a Scottish merchant whose bequest in 1813 formed the university's precursor, University of McGill College (or simply, McGill College); the name was officially changed to McGill University in 1885. McGill's main campus is on the slope of Mount Royal in downtown Montreal in the borough of Ville-Marie, with a second campus situated in Sainte-Anne-de-Bellevue, west of the main campus on Montreal Island. The university is one of two members of the Association of American Universities located outside the United States, alongside the University of Toronto, and is the only Canadian member of the Glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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