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Chemotactic Factors
Chemotaxis (from ''chemical substance, chemo-'' + ''taxis'') is the movement of an organism or entity in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell organism, single-cell or multicellular organisms direct their movements according to certain chemicals in their environment. This is important for bacteria to find food (e.g., glucose) by swimming toward the highest concentration of food molecules, or to flee from poisons (e.g., phenol). In multicellular organisms, chemotaxis is critical to early development (e.g., movement of sperm towards the egg during fertilization) and development (e.g., migration of neurons or lymphocytes) as well as in normal function and health (e.g., migration of White blood cell, leukocytes during injury or infection). In addition, it has been recognized that mechanisms that allow chemotaxis in animals can be subverted during cancer metastasis, and the aberrant change of the overall property of these networks, which contro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogenesis
Carcinogenesis, also called oncogenesis or tumorigenesis, is the formation of a cancer, whereby normal cell (biology), cells are malignant transformation, transformed into cancer cells. The process is characterized by changes at the cellular, Genetics, genetic, and Epigenetics, epigenetic levels and abnormal cell division. Cell division is a physiological process that occurs in almost all Tissue (biology), tissues and under a variety of circumstances. Normally, the balance between proliferation and programmed cell death, in the form of apoptosis, is maintained to ensure the integrity of tissues and Organ (anatomy), organs. According to the prevailing accepted theory of carcinogenesis, the somatic mutation theory, mutations in DNA and Epigenetics, epimutations that lead to cancer disrupt these orderly processes by interfering with the programming regulating the processes, upsetting the normal balance between proliferation and cell death. This results in uncontrolled cell division ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Walk
In mathematics, a random walk, sometimes known as a drunkard's walk, is a stochastic process that describes a path that consists of a succession of random steps on some Space (mathematics), mathematical space. An elementary example of a random walk is the random walk on the integer number line \mathbb Z which starts at 0, and at each step moves +1 or −1 with equal probability. Other examples include the path traced by a molecule as it travels in a liquid or a gas (see Brownian motion), the search path of a foraging animal, or the price of a fluctuating random walk hypothesis, stock and the financial status of a gambler. Random walks have applications to engineering and many scientific fields including ecology, psychology, computer science, physics, chemistry, biology, economics, and sociology. The term ''random walk'' was first introduced by Karl Pearson in 1905. Realizations of random walks can be obtained by Monte Carlo Simulation, Monte Carlo simulation. Lattice random ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julius Adler (biochemist)
Julius Adler (April 30, 1930 – April 2, 2024) was an American biochemist. He had been an Emeritus Professor of biochemistry and genetics at the University of Wisconsin–Madison since 1997. Early life Adler was born in Edelfingen, Germany in 1930. He came to the United States in 1938 at the age of 8 and became a naturalized citizen in 1943. His family settled in Grand Forks, North Dakota where their relatives were among the first Europeans to arrive in 1880. Since he was child, Adler had been fascinated by how organisms sense and respond to the environment. Education Adler attended Harvard University and received his A.B. in Biochemical Sciences in 1952. He then studied with Henry A. Lardy at the University of Wisconsin–Madison and earned an M.S. in Biochemistry in 1954 and a Ph.D. in Biochemistry in 1957. After graduating, Adler did postdoctoral fellowships with Arthur Kornberg in the Department of Microbiology at Washington University School of Medicine (1957–59) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henry Harris (scientist)
Sir Henry Harris (28 January 1925 – 31 October 2014) was an Australian professor of medicine at the University of Oxford who led pioneering work on cancer and human genetics in the 2000s. Early life and education Harris was born in 1925 to a Jewish family in the Soviet Union. In 1929, his family emigrated to Australia.''The Guardian'' Retrieved 11 December 2014 Harris studied at Sydney Boys High School from 1937 to 1941. In 1941, he first read modern languages, but was subsequently attracted to medicine through his literary interests. He studied medicine at the [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemotaxis Assay
Chemotaxis assays are experimental tools for evaluation of chemotactic ability of prokaryotic or eukaryotic cells. A wide variety of techniques have been developed. Some techniques are qualitative - allowing an investigator to approximately determine a cell's chemotactic affinity for an analyte - while others are quantitative, allowing a precise measurement of this affinity. Quality control In general, the most important requisite is to calibrate the incubation time of the assay both to the model cell and the ligand to be evaluated. Too short incubation time results in no cells in the sample, while too long time perturbs the concentration gradients and measures more chemokinetic than chemotactic responses. The most commonly used techniques are grouped into two main groups: Agar-plate techniques This way of evaluation deals with agar-agar or gelatine containing semi-solid layers made prior to the experiment. Small wells are cut into the layer and filled with cells and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocytosis
Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte. In a Multicellular organism, multicellular organism's immune system, phagocytosis is a major mechanism used to remove pathogens and cell debris. The ingested material is then digested in the phagosome. Bacteria, dead tissue cells, and small mineral particles are all examples of objects that may be phagocytized. Some protozoa use phagocytosis as means to obtain nutrients. The two main cells that do this are the Macrophages and the Neutrophils of the immune system. Where phagocytosis is used as a means of feeding and provides the organism part or all of its nourishment, it is called phagotrophy and is distinguished from osmotrophy, which is nutrition taking place by absorption. History The history of phag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Élie Metchnikoff
Ilya Ilyich Mechnikov (; – 15 July 1916), also spelled Élie Metchnikoff, was a zoologist from the Russian Empire of Moldavian noble ancestry and alshereat archive.org best known for his research in immunology (study of immune systems) and thanatology (study of death). Belkin, a Russian science historian, explains why Metchnikoff himself, in his Nobel autobiography – and subsequently, many other sources – mistakenly cited his date of birth as 16 May instead of 15 May. Metchnikoff made the mistake of adding 13 days to 3 May, his Old Style birthday, as was the convention in the 20th century. But since he had been born in the 19th century, only 12 days should have been added. He and Paul Ehrlich were jointly awarded the 1908 Nobel Prize in Physiology or Medicine "in recognition of their work on immunity". Mechnikov was born in a region of the Russian Empire that is today part of modern-day Ukraine to a Moldavian noble father and a Ukrainian-Jewish mother, and later on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different wikt:undulating, undulating pattern than flagella. Cilia occur in all members of the group (although the peculiar Suctoria only have them for part of their biological life cycle, life cycle) and are variously used in swimming, crawling, attachment, feeding, and sensation. Ciliates are an important group of protists, common almost anywhere there is water—in lakes, ponds, oceans, rivers, and soils, including anoxic and oxygen-depleted habitats. About 4,500 unique free-living species have been described, and the potential number of extant species is estimated at 27,000–40,000. Included in this number are many Ectosymbiosis, ectosymbiotic and endosymbiotic species, as well as some Obligate parasite, obligate and Facultative paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbert Spencer Jennings
Herbert Spencer Jennings (April 8, 1868 – April 14, 1947) was an American zoologist, geneticist, and eugenicist. His research helped demonstrate the link between physical and chemical stimulation and automatic responses in lower orders of animals (''Behavior of the Lower Organisms'', 1906). Life He was born in Tonica, Illinois, on April 8, 1868, the son of George Nelson Jennings and his wife Olive Taft Jenks. He studied at the University of Michigan graduating BS in 1893 then Harvard University where he gained a further AM degree in 1895 and a PhD in 1896. In 1906 he began a long and illustrious career at Johns Hopkins University in Baltimore where he stayed until retirement in 1938. He married twice: firstly in 1898 to Louisa Burridge and secondly in 1939 to Lulu Plant. He died in Santa Monica, California, on April 14, 1947. Career Jennings was elected to the American Philosophical Society in 1907 and both the American Academy of Arts and Sciences and the United States N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Pfeffer
Wilhelm Friedrich Philipp Pfeffer (9 March 1845 – 31 January 1920) was a German botanist and plant physiology, plant physiologist born in Grebenstein. Academic career He studied chemistry and pharmacy at the University of Göttingen, where his instructors included Friedrich Wöhler (1800-1882), William Eduard Weber (1804-1891) and Wilhelm Rudolph Fittig (1835-1910). Afterwards, he furthered his education at the universities of University of Marburg, Marburg and University of Berlin, Berlin. At Berlin, he studied under Alexander Braun (1805-1877) and was an assistant to Nathanael Pringsheim (1823-1894). Later on, he served as an assistant to Julius von Sachs (1832-1897) at University of Würzburg, Würzburg, In 1873 he was appointed professor of pharmacology and botany at the University of Bonn, followed by professorships at the Universities of University of Basel, Basel (from 1877) and University of Tübingen, Tübingen (from 1878), where he also served as director of the Bota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodor Wilhelm Engelmann
Theodor Wilhelm Engelmann (14 November 1843 – 20 May 1909) was a German botanist, physiologist, microbiologist, university professor, and musician whose 1882 experiment measured the effects of different colors of light on photosynthetic activity and showed that the conversion of light energy to chemical energy took place in the chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur .... Academic history Engelmann studied natural science and medicine first at the University of Jena, from 1861 to 1862, and later at the University of Heidelberg, the University of Göttingen and the University of Leipzig. In 1867, he received a doctoral degree in medicine at Leipzig. From 1870 he taught physiology at the University of Utrecht, becoming a professor in 1877. In 1897, he began ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
