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Carroll M. Williams
Carroll Milton Williams (December 2, 1916 in Oregon Hill, Virginia October 11, 1991 in Watertown, Massachusetts) was an American zoologist known for his work in entomology and developmental biology—in particular, metamorphosis in insects, for which he won the George Ledlie Prize. He performed groundbreaking surgical experiments on larvae and pupae, and developed multiple new techniques, including the use of carbon dioxide as an anesthetic. His impact on entomology has been compared to that of Vincent Wigglesworth. Education Williams was educated at the University of Richmond and Harvard University, where he was awarded a PhD in Zoology in 1941. Elected to the Harvard Society of Fellows, he also earned an MD summa cum laude. Career and research For his thesis he studied the wingbeat frequency of ''Drosophila'', using a stroboscope, stroboscopic device which he designed with the advice of Harold Edgerton. In 1942 Carroll Williams began a series of experiments that led t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oregon Hill
Oregon Hill is a historic working class, working-class neighborhood in Richmond, Virginia. Oregon Hill overlooks the James River (Virginia), James River and Belle Isle (Virginia), Belle Isle, and provides access to Hollywood Cemetery (Richmond, Virginia), Hollywood Cemetery. Due to the neighborhood's proximity to the Monroe Park Campus of Virginia Commonwealth University, the neighborhood is sometimes referred to as a student quarter because of its high college student population. William Byrd III established a rural estate on the property in 1758. Wealthy heiress Grace Arents helped build many institutions to serve the community. History In 1758, William Byrd III built his country house Belvidere on this hill, with views of the James River as well as Church Hill (Richmond, Virginia) and Shockoe Hill. Fire destroyed the house and gardens about a century later, by which time the neighborhood had transformed from an agricultural to industrial one. Construction of the James River a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associated Press
The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. newspapers and broadcasters. The AP has earned 56 Pulitzer Prizes, including 34 for photography, since the award was established in 1917. It is also known for publishing the widely used '' AP Stylebook''. By 2016, news collected by the AP was published and republished by more than 1,300 newspapers and broadcasters, English, Spanish, and Arabic. The AP operates 248 news bureaus in 99 countries. It also operates the AP Radio Network, which provides newscasts twice hourly for broadcast and satellite radio and television stations. Many newspapers and broadcasters outside the United States are AP subscribers, paying a fee to use AP material without being contributing members of the cooperative. As part of their cooperative agreement with the AP, most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B5
Cytochromes ''b''5 are ubiquitous electron transport hemoproteins found in animals, plants, fungi and purple phototrophic bacteria. The microsomal and mitochondrial variants are membrane-bound, while bacterial and those from erythrocytes and other animal tissues are water-soluble. The family of cytochrome ''b''5-like proteins includes (besides cytochrome ''b''5 itself) hemoprotein domains covalently associated with other redox domains in flavocytochrome cytochrome ''b''2 (L-lactate dehydrogenase; ), sulfite oxidase (), plant and fungal nitrate reductases (, , ), and plant and fungal cytochrome ''b''5/acyl lipid desaturase fusion proteins. Structure 3-D structures of a number of cytochrome ''b''5 and yeast flavocytochrome ''b''2 are known. The fold belongs to the α+β class, with two hydrophobic cores on each side of a β-sheet. The larger hydrophobic core constitutes the heme-binding pocket, closed off on each side by a pair of helices connected by a turn. The smaller hydro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocoonase
Cocoonase is a trypsin-like proteolytic enzyme produced by silkworms (of both ''Bombyx'' and ''Antheraea'' species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis and exuded onto the galeae. Its function is to weaken the fibers of the cocoon, thereby facilitating the emergence of the adult insect. It was discovered by Carroll Williams. , from the ; published March 21, 1996; retrieved November 16, 2011 External links [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diapause
In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It is a physiological state with very specific initiating and inhibiting conditions. The mechanism is a means of surviving predictable, unfavorable environmental conditions, such as temperature extremes, drought, or reduced food availability. Diapause is observed in all the life stages of arthropods, especially insects. Embryonic diapause, a somewhat similar phenomenon, occurs in over 130 species of mammals, possibly even in humans, and in the embryos of many of the oviparous species of fish in the order Cyprinodontiformes. Activity levels of diapausing stages can vary considerably among species. Diapause may occur in a completely immobile stage, such as the pupae and eggs, or it may occur in very active stages that undergo extensive migrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juvenile Hormone
Juvenile hormones (JHs) are a group of acyclic sesquiterpenoids that regulate many aspects of insect physiology. The first discovery of a JH was by Vincent Wigglesworth. JHs regulate development, reproduction, diapause, and polyphenisms.The chemical formula for juvenile hormone is C_18H_30O_3. In insects, JH (formerly called neotenin) refers to a group of hormones, which ensure growth of the larva, while preventing metamorphosis. Because of their rigid exoskeleton, insects grow in their development by successively shedding their exoskeleton (a process known as molting). Juvenile hormones are secreted by a pair of endocrine glands behind the brain called the corpora allata. JHs are also important for the production of eggs in female insects. JH was isolated in 1965 by Karel Sláma and Carroll Williams and the first molecular structure of a JH was solved in 1967. Most insect species contain only juvenile growth hormone (JH) III. To date JH 0, JH I, and JH II have been identifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecdysone
Ecdysone is a prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. It is of steroidal structure. Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids. Ecdysteroids act as moulting hormones of arthropods but also occur in other related phyla where they can play different roles. In ''Drosophila melanogaster'', an increase in ecdysone concentration induces the expression of genes coding for proteins that the larva requires, and it causes chromosome puffs (sites of high expression) to form in polytene chromosomes. Recent findings in the laboratory of Chris Q. Doe have found a novel role of this hormone in regulating temporal gene transitions within neural stem cells of the fruit fly. Ecdysone and other ecdysteroids also appear in many plants mostly as a protection agent ( toxins or antifeedants) against herbivorous insects. These phytoecdysteroids have been reputed to have medicinal va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prothoracic Gland
The prothoracic glands are either of a pair of endocrine glands located in the prothorax of certain insects that regulate molting. They have an ectodermal origin and secrete ecdysteroids, such as ecdysone Ecdysone is a prohormone of the major insect molting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. It is of steroidal structure. Insect molting hormones (ecdysone and its homologues) are generally called ecdysteroids. ... and 20-hydroxyecdysone. The chemical formula of ecodysin hormone is (). They usually disappear in adults. References Insect anatomy Arthropod glands {{Insect-anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyalophora Cecropia
''Hyalophora cecropia'', the cecropia moth, is North America's largest native moth. It is a member of the family Saturniidae, or giant silk moths. Females have been documented with a wingspan of five to seven inches (160 mm) or more. These moths can be found all across North America as far west as Washington and north into the majority of Canadian provinces. Cecropia moth larvae are most commonly found on maple trees, but they have also been found on cherry and birch trees among many others. The species was first described by Carl Linnaeus in his 1758 10th edition of ''Systema Naturae''. Life cycle Like other members of the giant silk moth family, the cecropia moth lacks functional mouth parts and a digestive system. Due to this, they survive approximately two weeks. To find a mate, the female cecropia moth emits pheromones which the male detects with its sensitive antennae. Male cecropia moths can detect these pheromones from up to a mile away, although a male may fly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Edgerton
Harold Eugene "Doc" Edgerton (April 6, 1903 – January 4, 1990), also known as Papa Flash, was an American scientist and researcher, a professor of electrical engineering at the Massachusetts Institute of Technology. He is largely credited with transforming the stroboscope from an obscure laboratory instrument into a common device. He also was deeply involved with the development of sonar and deep-sea photography, and his equipment was used by Jacques Cousteau in searches for shipwrecks and even the Loch Ness Monster. Biography Early years Edgerton was born in Fremont, Nebraska, on April 6, 1903, the son of Mary Nettie Coe and Frank Eugene Edgerton, a descendant of Samuel Edgerton, the son of Richard Edgerton, one of the founders of Norwich, Connecticut and Alice Ripley, a great-granddaughter of Governor William Bradford (1590–1657) of the Plymouth Colony and a passenger on the Mayflower. His father was a lawyer, journalist, author and orator and served as the assistant att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stroboscope
A stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. It consists of either a rotating disk with slots or holes or a lamp such as a flashtube which produces brief repetitive flashes of light. Usually, the rate of the stroboscope is adjustable to different frequencies. When a rotating or vibrating object is observed with the stroboscope at its vibration frequency (or a submultiple of it), it appears stationary. Thus stroboscopes are also used to measure frequency. The principle is used for the study of rotating, reciprocating, oscillating or vibrating objects. Machine parts and vibrating string are common examples. A stroboscope used to set the ignition timing of internal combustion engines is called a timing light. Mechanical In its simplest mechanical form, a stroboscope can be a rotating cylinder (or bowl with a raised edge) with evenly spaced holes or slots placed in the line of si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila
''Drosophila'' () is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, ''D. melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literature. The entire genus, however, contains more than 1,500 species and is very diverse in appearance, be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
