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Intracellular Parasite
Intracellular parasites are microparasites that are capable of growing and reproducing inside the cells of a host. They are also called intracellular pathogens. Types There are two main types of intracellular parasites: Facultative and Obligate. Facultative intracellular parasites are capable of living and reproducing in or outside of host cells. Obligate intracellular parasites, on the other hand, need a host cell to live and reproduce. Many of these types of cells require specialized host types, and invasion of host cells occurs in different ways. Facultative Facultative intracellular parasites are capable of living and reproducing either inside or outside cells. Bacterial examples include: Fungal examples include: Obligate Obligate intracellular parasites cannot reproduce outside their host cell, meaning that the parasite's reproduction is entirely reliant on intracellular resources. All viruses are obligate intracellular parasites. Bacterial examples (that affect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microparasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites' way of feeding as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histoplasma Capsulatum
''Histoplasma capsulatum'' is a species of dimorphic fungus. Its sexual form is called ''Ajellomyces capsulatus''. It can cause pulmonary and disseminated histoplasmosis. ''Histoplasma capsulatum'' is "distributed worldwide, except in Antarctica, but most often associated with river valleys" and occurs chiefly in the " Central and Eastern United States" followed by " Central and South America, and other areas of the world". It is most prevalent in the Ohio and Mississippi River valleys. It was discovered by Samuel Taylor Darling in 1906. Growth and morphology ''Histoplasma capsulatum'' is an ascomycetous fungus closely related to '' Blastomyces dermatitidis''. It is potentially sexual, and its sexual state, ''Ajellomyces capsulatus'', can readily be produced in culture, though it has not been directly observed in nature. ''H. capsulatum'' groups with ''B. dermatitidis'' and the South American pathogen '' Paracoccidioides brasiliensis'' in the recently recognized fungal fami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protozoa
Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals". When first introduced by Georg Goldfuss, in 1818, the taxon Protozoa was erected as a class within the Animalia, with the word 'protozoa' meaning "first 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. This classification remained widespread in the 19th and early 20th century, and even became elevated to a variety of higher ranks, including phylum, subkingdom, kingdom, and then sometimes included within the paraphyletic Protoctista or Protista. By the 1970s, it became usual to require that all taxa be monophyletic (derived from a common ancestor that would also be regarded as protozo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaplasma Phagocytophilum
''Anaplasma phagocytophilum'' (formerly ''Ehrlichia phagocytophilum'') is a Gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis.Tick-Borne Fever reviewed and published by WikiVet, accessed 12 October 2011. ''A. phagocytophilum'' is a Gram-negative, bacterium of neutrophils. It causes human granulocytic anaplasmosis, which is a tick-borne rickettsial disease. Because th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phagocyte
Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ''kutos,'' "hollow vessel". They are essential for fighting infections and for subsequent immunity. Phagocytes are important throughout the animal kingdom and are highly developed within vertebrates. One litre of human blood contains about six billion phagocytes. They were discovered in 1882 by Ilya Ilyich Mechnikov while he was studying starfish larvae.Ilya Mechnikov retrieved on November 28, 2008. Fro ''Physiology or Medicine 1901–192 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycobacterium Leprae
''Mycobacterium leprae'' (also known as the leprosy bacillus or Hansen's bacillus) is one of the two species of bacteria that cause Hansen's disease (leprosy), a chronic but curable infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, and muscles. It is an acid-fast, Gram-positive, rod shaped bacterium and an obligate intracellular parasite, which means, unlike its relative ''Mycobacterium tuberculosis'', it cannot be grown in cell-free laboratory media. This is likely due to gene deletion and decay that the genome of the species has experienced via reductive evolution, which has caused the bacterium to depend heavily on its host for nutrients and metabolic intermediates. It has a narrow host range and apart from humans, the only other natural hosts are nine-banded armadillo and red squirrels. The bacteria infect mainly macrophages and Schwann cells, and are typically found congregated as a palisade. ''Mycobacterium leprae'' was sensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coxiella (bacterium)
''Coxiella'' refers to a genus of Gram-negative bacteria in the family Coxiellaceae. It is named after Herald Rea Cox (1907–1986), an American bacteriologist. It is part of the Gammaproteobacteria. '' Coxiella burnetii'' is the best known member of this genus. It is an intracellular parasite and it survives within the phagolysosomes of its host. It causes Q fever. The majority of ''Coxiella''’s described members are non pathogenic forms which are often found in ticks. Approximately two-thirds of tick species harbour ''Coxiella''-like endosymbionts required for tick survival and reproduction. Genomes of ''Coxiella''-like endosymbionts encode pathways for the biosynthesis of major B vitamins and co-factors that fit closely with the expected nutritional complements required for strict haematophagy. The experimental elimination of ''Coxiella''-like endosymbionts typically results in decreased tick survival, molting, fecundity and egg viability, as well as in physical abno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rickettsia
''Rickettsia'' is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci (0.1 μm in diameter), bacilli (1–4 μm long), or threads (up to about 10 μm long). The genus was named after Howard Taylor Ricketts in honor of his pioneering work on tick-borne spotted fever. Properly, ''Rickettsia'' is the name of a single genus, but the informal term "rickettsia", plural "rickettsias," usually not capitalised, commonly applies to any members of the order Rickettsiales. Being obligate intracellular bacteria, rickettsias depend on entry, growth, and replication within the cytoplasm of living eukaryotic host cells (typically endothelial cells). Accordingly, ''Rickettsia'' species cannot grow in artificial nutrient culture; they must be grown either in tissue or embryo cultures. Mostly chicken embryos are used, following a method developed by Ernest William Goodpasture and his colleagues at Vanderbilt University i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydia (bacterium)
''Chlamydia'' is a genus of pathogenic Gram-negative bacteria that are obligate intracellular parasites. ''Chlamydia'' infections are the most common bacterial sexually transmitted diseases in humans and are the leading cause of infectious blindness worldwide. Humans mainly contract '' C. trachomatis'', '' C. pneumoniae'', ''C. abortus'', and '' C. psittaci''. Classification Because of ''Chlamydia''s unique developmental cycle, it was taxonomically classified in a separate order. ''Chlamydia'' is part of the order Chlamydiales, family Chlamydiaceae. ' (1999–2009) Earlier criteria for differentiation of chlamydial species did not always work well. For example, at that time '' C. psittaci'' was distinguished from '' C. trachomatis'' by sulfadiazine resistance, although not all strains identified as ''C. psittaci'' at the time were resistant, and '' C. pneumoniae'' was classified by its appearance under electron microscopy (EM) and its ability to infect humans, although th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of List of virus species, virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intracellular
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology, Glossary of environmental science and Glossary of scientific naming, or any of the organism-specific glossaries in :Glossaries of biology. A B C D E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproduction
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: Asexual reproduction, asexual and Sexual reproduction, sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to unicellular organism, single-celled organisms. The cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes.John Maynard Smith ''The Evolution of Sex'' 1978. Sexual reproduction typically requires the sexual interaction of two specialized reproductive cells, called gametes, which contain half t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
