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Histomonas Meleagridis
''Histomonas meleagridis'' is a species of parasitic protozoan that infects a wide range of birds including chickens, turkeys, peafowl, quail and pheasants, causing infectious enterohepatitis, or histomoniasis (blackhead diseases). ''H. meleagridis'' can infect many birds, but it is most deadly in turkeys. It inhabits the lumen of cecum and parenchyma of liver, where it causes extensive necrosis. It is transmitted by another cecal parasite, the nematode ''Heterakis gallinarum''. Description ''H. meleagridis'' is a microscopic, pleomorphic protozoan, and can exist in two forms, amoeboid and flagellated. Within the tissue, it is present as an amoeboid protozoan, while in the lumen or free in the contents of cecum, it lives as an elongated flagellated form. The amoeboid form is typically 8-15 μm in diameter, whereas the flagellated form can reach up to 30 μm in diameter.Griffiths HJ (1978). ''A Handbook of Veterinary Parasitology: Domestic Animals of North America''. Uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryota
Eukaryotes () are organisms whose Cell (biology), cells have a cell nucleus, nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the Three-domain system, three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard (archaea), Asgard archaea. This implies that there are only Two-domain system, two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass (ecology), biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as Flagellated cell, flagellated phagotrophs. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it is located in the quadrant (anatomy), right upper quadrant of the abdomen, below the thoracic diaphragm, diaphragm. Its other roles in metabolism include the regulation of Glycogen, glycogen storage, decomposition of red blood cells, and the production of hormones. The liver is an accessory digestive organ that produces bile, an alkaline fluid containing cholesterol and bile acids, which helps the fatty acid degradation, breakdown of fat. The gallbladder, a small pouch that sits just under the liver, stores bile produced by the liver which is later moved to the small intestine to complete digestion. The liver's highly specialized biological tissue, tissue, consisting mostly of hepatocytes, regulates a w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flocks
Flocking is the behaviour exhibited when a group of birds, called a flock, are foraging or in flight. Computer simulations and mathematical models that have been developed to emulate the flocking behaviours of birds can also generally be applied to the "flocking" behaviour of other species. As a result, the term "flocking" is sometimes applied, in computer science, to species other than birds. This article is about the modelling of flocking behaviour. From the perspective of the mathematical modeller, "flocking" is the collective motion by a group of self-propelled entities and is a collective animal behaviour exhibited by many living beings such as birds, fish, bacteria, and insects. It is considered an emergent behaviour arising from simple rules that are followed by individuals and does not involve any central coordination. In nature There are parallels with the shoaling behaviour of fish, the swarming behaviour of insects, and herd behaviour of land animals. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trophozoites
A trophozoite (G. ''trope'', nourishment + ''zoon'', animal) is the activated, feeding stage in the life cycle of certain protozoa such as malaria-causing '' Plasmodium falciparum'' and those of the '' Giardia'' group. (The complement of the trophozoite state is the thick-walled cyst form). Life cycle stages Trophozoite and cyst stages are shown in the life cycle of '' Balantidium coli'' the causative agent of balantidiasis. In the apicomplexan life cycle the trophozoite undergoes schizogony (asexual reproduction) and develops into a schizont which contains merozoites Apicomplexans, a group of intracellular parasites, have life cycle stages that allow them to survive the wide variety of environments they are exposed to during their complex life cycle. Each stage in the life cycle of an apicomplexan organism is .... The trophozoite life stage of '' Giardia'' colonizes and proliferates in the small intestine. Trophozoites develop during the course of the infection into cysts wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary Fission
Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that takes two arguments * Binary relation, a relation involving two elements * Binary-coded decimal, a method for encoding for decimal digits in binary sequences * Finger binary, a system for counting in binary numbers on the fingers of human hands Computing * Binary code, the digital representation of text and data * Bit, or binary digit, the basic unit of information in computers * Binary file, composed of something other than human-readable text ** Executable, a type of binary file that contains machine code for the computer to execute * Binary tree, a computer tree data structure in which each node has at most two children Astronomy * Binary star, a star system with two stars in it * Binary planet, two planetary bodies of comparable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Units (SI) equalling (SI standard prefix "micro-" = ); that is, one millionth of a metre (or one thousandth of a millimetre, , or about ). The nearest smaller common SI unit is the nanometre, equivalent to one thousandth of a micrometre, one millionth of a millimetre or one billionth of a metre (). The micrometre is a common unit of measurement for wavelengths of infrared radiation as well as sizes of biological cells and bacteria, and for grading wool by the diameter of the fibres. The width of a single human hair ranges from approximately 20 to . The longest human chromosome, chromosome 1, is approximately in length. Examples Between 1 μm and 10 μm: * 1–10 μm – length of a typical bacterium * 3–8 μm – width of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagellation
Flagellation (Latin , 'whip'), flogging or whipping is the act of beating the human body with special implements such as whips, rods, switches, the cat o' nine tails, the sjambok, the knout, etc. Typically, flogging has been imposed on an unwilling subject as a punishment; however, it can also be submitted to willingly and even done by oneself in sadomasochistic or religious contexts. The strokes are typically aimed at the unclothed back of a person, though they can be administered to other areas of the body. For a moderated subform of flagellation, described as ''bastinado'', the soles of a person's bare feet are used as a target for beating (see foot whipping). In some circumstances the word ''flogging'' is used loosely to include any sort of corporal punishment, including birching and caning. However, in British legal terminology, a distinction was drawn (and still is, in one or two colonial territories) between ''flogging'' (with a cat o' nine tails) and ''whippi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeboid
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the class or subphylum Sarcodina, a grouping of single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic group whose members share common descent. Consequently, amoeboid organisms are no longer classified together in one group.Jan Pawlow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphism (biology)
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protozoan
Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Historically, protozoans were regarded as "one-celled animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae. When first introduced by Georg Goldfuss (originally spelled Goldfuß) in 1818, the taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first animals". In later classification schemes it was elevated to a variety of higher ranks, including phylum, subkingdom and kingdom, and sometimes included within Protoctista or Protista. The approach of classifying Protozoa within the context of Animalia was widespread in the 19th and early 20th century, but not universal. By the 1970s, it became usual to require th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleomorphism (microbiology)
In microbiology, pleomorphism (from Ancient Greek , ''pléō'', "more", and , ''morphḗ'', form), also pleiomorphism, is the ability of some microorganisms to alter their morphology, biological functions or reproductive modes in response to environmental conditions. Pleomorphism has been observed in some members of the Deinococcaceae family of bacteria. The modern definition of pleomorphism in the context of bacteriology is based on ''variation'' of morphology or functional methods of the individual cell, rather than a heritable ''change'' of these characters as previously believed. Bacteria In the first decades of the 20th century, the term "pleomorphism" was used to refer to the idea that bacteria change morphology, biological systems, or reproductive methods dramatically according to environmental cues. This claim was controversial among microbiologists of the time, and split them into two schools: the monomorphists, who opposed the claim, and the pleomorphists such as Antoine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microscopic
The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens (optics), lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale between the macroscopic scale and the quantum realm, quantum scale. Microscopic units and measurements are used to classify and describe very small objects. One common microscopic length scale unit is the micrometre (also called a ''micron'') (symbol: μm), which is one millionth of a metre. History Whilst compound microscopes were first developed in the 1590s, the significance of the microscopic scale was only truly established in the 1600s when Marcello Malpighi, Marcello Malphigi and Antonie van Leeuwenhoek microscopically observed frog lungs and microorganisms. As microbiology was established, the significance of making scientific observations at a microscopic level increased. Published in 1665, Robert Hooke’s book Mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
