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Bacteriocyte
A bacteriocyte ( Greek for ''bacteria cell''), also known as a mycetocyte, is a specialized adipocyte found primarily in certain insect groups such as aphids, tsetse flies, German cockroaches, weevils. These cells contain endosymbiotic organisms such as bacteria and fungi, which provide essential amino acids and other chemicals to their host. Bacteriocytes may aggregate into a specialized organ called the bacteriome. Endosymbiosis with microorganisms is common in insects. More than 10% of insect species rely upon intracellular bacteria for their development and survival.Baumann P, Moran NA, Baumann L, editors. (2000) Bacteriocyte-associated endosymbionts of insects. In: Dworkin M, editor. The prokaryotes nline New York: Springer. Available: http://link.springer.de/link/service/books/10125/. Endosymbionts and their relationships with their hosts are diverse both functionally and genetically. However, the host cell in which bacterial and fungal endosymbionts reside is mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buchnera (bacterium)
''Buchnera aphidicola'', a member of the Pseudomonadota and the only species in the genus ''Buchnera'', is the primary endosymbiont of aphids, and has been studied in the pea aphid, ''Acyrthosiphon pisum''. ''Buchnera'' is believed to have had a free-living, Gram-negative ancestor similar to a modern Enterobacterales, such as ''Escherichia coli''. ''Buchnera'' is 3 µm in diameter and has some of the key characteristics of their Enterobacterales relatives, such as a Gram-negative cell wall. However, unlike most other Gram-negative bacteria, ''Buchnera'' lacks the genes to produce lipopolysaccharides for its outer membrane. The long association with aphids and the limitation of crossover events due to strictly vertical transmission has seen the deletion of genes required for anaerobic respiration, the synthesis of amino sugars, fatty acids, phospholipids, and complex carbohydrates. This has resulted not only in one of the smallest known genomes of any living organism, but al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphid
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A typical life cycle involves flightless females giving live birth to female nymphs—who may also be already pregnant, an adaptation scientists call telescoping generations—without the involvement of males. Maturing rapidly, females breed profusely so that the number of these insects multiplies quickly. Winged females may develop later in the season, allowing the insects to colonize new plants. In temperate regions, a phase of sexual reproduction occurs in the autumn, with the insects often overwintering as eggs. The life cycle of some species involves an alternation between two species of host plants, for example between an annual crop and a woody plant. Some species feed on only one type of plant, while others are generalists, colon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosymbiosis
An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within", σύν ''syn'' "together" and βίωσις ''biosis'' "living".) Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root nodules of legumes, single-cell algae inside reef-building corals and bacterial endosymbionts that provide essential nutrients to insects. There are two types of symbiont transmissions. In horizontal transmission, each new generation acquires free living symbionts from the environment. An example is the nitrogen-fixing bacteria in certain plant roots. Vertical transmission takes place when the symbiont is transferred directly from parent to offspring. It is also possible for both to be involved in a mixed-mode transmission, where symbionts are transferred vertically for some generation befor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteriome
A bacteriome is a specialized organ, found mainly in some insects, that hosts endosymbiotic bacteria. Bacteriomes contain specialized cells, called bacteriocytes, that provide nutrients and shelter to the bacteria while protecting the host animal. In exchange, the bacteria provide essentials like vitamins and amino acids to the host insect. Bacteriomes also protect the bacteria from the host's immune system, with insects secreting antimicrobial peptides such as the coleoptericin secreted by weevils to keep bacteria within the bacteriome. Some insects, like the glassy-winged sharpshooter, host more than one species of bacteria. In armored scale insects, bacteriomes have unique genetic and sexual properties. For example, they have five copies of each chromosome—including two copies of the mother's complete genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tsetse Flies
Tsetse ( , or ) (sometimes spelled tzetze; also known as tik-tik flies), are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus ''Glossina'', which are placed in their own family, Glossinidae. The tsetse are obligate parasites, which live by feeding on the blood of vertebrate animals. Tsetse have been extensively studied, because of their role in transmitting disease. They have a prominent economic impact in sub-Saharan Africa, as the biological vectors of trypanosomes, causing human and animal trypanosomiasis. Tsetse are multivoltine and long-lived, typically producing about four broods per year, with up to 31 broods over their lifespans. Tsetse can be distinguished from other large flies by two easily-observed features: Primarily, tsetse fold their wings over their abdomens completely when they are resting (so that one wing rests directly on top of the other); Secondly, tsetse also have a long proboscis, extending d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wigglesworthia Glossinidia
''Wigglesworthia glossinidia'' is a species of gram-negative bacteria which was isolated from the gut of the tsetse fly. ''W. glossinidia'' is a bacterial endosymbiont of the tsetse fly. Because of this relationship, ''Wigglesworthia'' has lost a large part of its genome and has one of the smallest known genomes of any living organism, consisting of a single chromosome of 700,000 bp and a plasmid of 5,200. Together with ''Buchnera aphidicola'', ''Wigglesworthia'' has been the subject of genetic research into the minimal genome necessary for any living organism. ''Wigglesworthia'' also synthesizes key B-complex vitamins which the tsetse fly does not get from its diet of blood. Without the vitamins ''Wigglesworthia'' produces, the tsetse fly has greatly reduced growth and reproduction.Nogge, G. 1976. Sterility in tsetse flies (Glossina morsitans Westwood) caused by loss of symbionts. Experientia 32, 995−996. Since the tsetse fly is the primary vector of ''Trypanosoma brucei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the ner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrabithorax
Ultrabithorax (Ubx) is a homeobox gene found in insects, and is used in the regulation of patterning in morphogenesis. There are many possible products of this gene, which function as transcription factors. Ubx is used in the specification of serially homologous structures, and is used at many levels of developmental hierarchies. In ''Drosophila melanogaster'' it is expressed in the third thoracic (T3) and first abdominal (A1) segments and represses wing formation. The Ubx gene regulates the decisions regarding the number of wings and legs the adult flies will have. The developmental role of the Ubx gene is determined by the splicing of its product, which takes place after translation of the gene. The specific splice factors of a particular cell allow the specific regulation of the developmental fate of that cell, by making different splice variants of transcription factors. In ''D. melanogaster'', at least six different isoforms of Ubx exist. Mutations of the Ubx gene will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nysius
''Nysius'' is a genus of false chinch bugs in the family Lygaeidae. At least 100 described species are placed in ''Nysius''. Like other seed bugs, some species in the genus have proven to be crop pests of wheat and other grains (including ''N. huttoni''), as well as many vegetables. A unique Hawaiian radiation of the genus contains almost a quarter of the world's species (26), as well as the most diverse character set seen in the genus. In addition, two closely related species (colloquially known as wēkiu bugs) found on Mauna Loa and Mauna Kea on the island of Hawai'i, are different from the rest of ''Nysius'' by exhibiting reduced nonfunctional wings, and feed on dead and dying insects ('' N. wekiuicola'', '' N. aa'' ). Species The genus contains the following species: * '' Nysius aa'' Polhemus, 1998 * '' Nysius abnormis'' Usinger, 1942 * '' Nysius albipennis'' Distant, W.L., 1913 * '' Nysius angustatus'' Uhler, 1872 * '' Nysius angustellus'' (Blanchard, 1852) * '' Nys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Language
Greek ( el, label= Modern Greek, Ελληνικά, Elliniká, ; grc, Ἑλληνική, Hellēnikḗ) is an independent branch of the Indo-European family of languages, native to Greece, Cyprus, southern Italy ( Calabria and Salento), southern Albania, and other regions of the Balkans, the Black Sea coast, Asia Minor, and the Eastern Mediterranean. It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet, which has been used for approximately 2,800 years; previously, Greek was recorded in writing systems such as Linear B and the Cypriot syllabary. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic, and many other writing systems. The Greek language holds a very important place in the history of the Western world. Beginning with the epics of Homer, ancient Greek literature includes many works ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antennapedia
''Antennapedia'' (abbreviated ''Antp'') is a Hox gene first discovered in ''Drosophila'' which controls the formation of legs during development. Loss-of-function mutations in the regulatory region of this gene result in the development of the second leg pair into ectopic antennae. By contrast gain-of-function alleles convert antennae into ectopic legs. This is just one illustration of the tendency of organisms to exhibit variations on a theme: modulated repetition. Legs and antennae are related to one another as much as molars are to incisors, fingers are to toes, and arms are to legs. ''Antp'' also refers to a gene complex (ANT-C) in ''Drosophila'' ending with the ''Antp'' gene. It is responsible for formation and differentiation of the thoracic and head segments of the fly's body. Origin of ''Antennapedia''-class homeobox gene The origin of the ancestor homeobox gene is an important aspect of the evolution of the ''Antp''-class ''Hox'' genes. Early evolution of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemolymph
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods (e.g. arachnids, crustaceans and insects). In addition, some non-arthropods such as molluscs possess a hemolymphatic circulatory system. Oxygen-transport systems were long thought unnecessary in insects, but ancestral and functional hemocyanin has been found in the hemolymph. Insect "blood" generally does not carry hemoglobin, although hemoglobin may be present in the tracheal system instead and play some role in respiration. Method of transport In the grasshopper, the closed portion of the system consists of tubular hearts and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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