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Kinetoplast
A kinetoplast is a network of circular DNA (called kDNA) inside a large mitochondrion that contains many copies of the mitochondrial genome. The most common kinetoplast structure is a disk, but they have been observed in other arrangements. Kinetoplasts are only found in Excavata of the class Kinetoplastida. The variation in the structures of kinetoplasts may reflect phylogenic relationships between kinetoplastids. A kinetoplast is usually adjacent to the organism's flagellar basal body, suggesting that it is tightly bound to the cytoskeleton. In '' Trypanosoma brucei'' this cytoskeletal connection is called the tripartite attachment complex and includes the protein p166. ''Trypanosoma'' In trypanosomes, a group of flagellated protozoans, the kinetoplast exists as a dense granule of DNA within the large mitochondrion. '' Trypanosoma brucei'', the parasite which causes African trypanosomiasis (African sleeping sickness), is an example of a trypanosome with a kinetoplast. Its ki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetoplastida
Kinetoplastida (or Kinetoplastea, as a class) is a group of flagellated protists belonging to the phylum Euglenozoa, and characterised by the presence of an organelle with a large massed DNA called kinetoplast (hence the name). The organisms are commonly referred to as "kinetoplastids" or "kinetoplasts" The group includes a number of parasites responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments. Their distinguishing feature, the presence of a kinetoplast, is an unusual DNA-containing granule located within the single mitochondrion associated with the base of the cell's flagellum (the basal body). The kinetoplast contains many copies of the mitochondrial genome. The kinetoplastids were first defined by Bronislaw M. Honigberg in 1963 as the members of the flagellated protozoans. They are traditionally divided into the biflagellate Bodonidae and uniflagellate Trypanosomatidae; the former appears to be paraphyle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetoplast Of Trypanosoma Brucei
A kinetoplast is a network of circular DNA (called kDNA) inside a large mitochondrion that contains many copies of the mitochondrial genome. The most common kinetoplast structure is a disk, but they have been observed in other arrangements. Kinetoplasts are only found in Excavata of the class Kinetoplastida. The variation in the structures of kinetoplasts may reflect phylogenic relationships between kinetoplastids. A kinetoplast is usually adjacent to the organism's flagellar basal body, suggesting that it is tightly bound to the cytoskeleton. In ''Trypanosoma brucei'' this cytoskeletal connection is called the tripartite attachment complex and includes the protein p166. ''Trypanosoma'' In trypanosomes, a group of flagellated protozoans, the kinetoplast exists as a dense granule of DNA within the large mitochondrion. ''Trypanosoma brucei'', the parasite which causes African trypanosomiasis (African sleeping sickness), is an example of a trypanosome with a kinetoplast. Its kinetop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bodo Saltans
''Bodo saltans'' (alternatively known as ''Pleuromonas jaculans'') is a free-living nonparasitic species of kinetoplastid flagellated phagotrophic protozoa that feed on bacteria. ''Bodo saltans'' cells have been reported in freshwater and marine environments. ''Bodo saltans'' is a single-celled bean-shaped organism 4 to 5 micrometers in length. It has two flagella: a short anterior projecting flagellum and a longer posterior-projecting flagellum without hairs (acronematic) that extends beyond the length of the cell. ''B. saltans'' secures itself to the substrate of its aquatic habitat by the tip of a posterior flagellum. Flexing of the posterior flagellum results in a twitching, jumping movement that is characteristic of this species. This type of movement appears similar to the undulating membrane of the sexually-transmitted pathogen ''Trichomonas vaginalis'' and can result in a false-positive diagnosis in cases where ''B. saltans'' is a contaminant in test samples, especially if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excavata
Excavata is a major supergroup of unicellular organisms belonging to the domain Eukaryota. It was first suggested by Simpson and Patterson in 1999 and introduced by Thomas Cavalier-Smith in 2002 as a formal taxon. It contains a variety of free-living and symbiotic forms, and also includes some important parasites of humans, including ''Giardia'' and ''Trichomonas''. Excavates were formerly considered to be included in the now obsolete Protista kingdom. They are classified based on their flagellar structures, and they are considered to be the most basal flagellate lineage. Phylogenomic analyses split the members of Excavata into three different and not all closely related groups: Discobids, Metamonads and Malawimonads. Except for Euglenozoa, they are all non-photosynthetic. Characteristics Most excavates are unicellular, heterotrophic flagellates. Only the Euglenozoa are photosynthetic. In some (particularly anaerobic intestinal parasites), the mitochondria have been greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crithidia Fasciculata
''Crithidia fasciculata'' is a species of parasitic excavates. ''C. fasciculata'', like other species of ''Crithidia'' have a single host life cycle with insect host, in the case of ''C. fasciculata'' this is the mosquito. ''C. fasciculata'' have low host species specificity and can infect many species of mosquito. Life cycle ''C. fasciculata'' is found in two morphologically different life cycle stages - the free swimming choanomastigote form, which has a long external flagellum for motility, and the attached, immotile, amastigote form in the mosquito gut. Amastigotes excreted in the faeces contaminate the mosquito habitat; contamination of flowers during nectar feeding is common. Transmission of ''C fasciculata'' primarily occurs when amastigotes, washed into standing water, are ingested by mosquito larvae. The amastigotes are typically found in the rectum of a larva. Each molt of the larva results in loss of infection, but it is generally quickly re-acquired from the environ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Trypanosomiasis
African trypanosomiasis, also known as African sleeping sickness or simply sleeping sickness, is an insect-borne parasitic infection of humans and other animals. It is caused by the species ''Trypanosoma brucei''. Humans are infected by two types, ''Trypanosoma brucei gambiense'' (TbG) and '' Trypanosoma brucei rhodesiense'' (TbR). TbG causes over 98% of reported cases. Both are usually transmitted by the bite of an infected tsetse fly and are most common in rural areas. Initially, the first stage of the disease is characterized by fevers, headaches, itchiness, and joint pains, beginning one to three weeks after the bite. Weeks to months later, the second stage begins with confusion, poor coordination, numbness, and trouble sleeping. Diagnosis is by finding the parasite in a blood smear or in the fluid of a lymph node. A lumbar puncture is often needed to tell the difference between first- and second-stage disease. If the disease is not treated quickly it can lead to death. P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypanosoma Brucei
''Trypanosoma brucei'' is a species of parasitic Kinetoplastida, kinetoplastid belonging to the genus ''Trypanosoma'' that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids. It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or ''nagana'' in cattle and horses. It is a species complex grouped into three subspecies: ''T. b. brucei'', ''T. b. gambiense'' and ''T. b. rhodesiense''. The first is a parasite of non-human mammals and causes ''nagana'', while the latter two are zoonotic infecting both humans and animals and cause African trpanosomiasis. ''T. brucei'' is transmitted between mammal hosts by an insect Vector (epidemiology), vector belonging to different species of tsetse fly (''Glossina''). Transmission occurs by biting during the insect's blood meal. The parasites un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypanosoma
''Trypanosoma'' is a genus of kinetoplastids (class Trypanosomatidae), a monophyletic group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Sarcomastigophora. The name is derived from the Greek ''trypano-'' (borer) and ''soma'' (body) because of their corkscrew-like motion. Most trypanosomes are heteroxenous (requiring more than one obligatory host to complete life cycle) and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Some, such as '' Trypanosoma equiperdum'', are spread by direct contact. In an invertebrate host they are generally found in the intestine, but normally occupy the bloodstream or an intracellular environment in the vertebrate host. Trypanosomes infect a variety of hosts and cause various diseases, including the fatal human diseases sleeping sickness, caused by ''Trypanosoma brucei'', and Chagas disease, caused ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minicircles
Minicircles are small (~4 kb) circular replicons. They occur naturally in some eukaryotic organelle genomes. In the mitochondria-derived kinetoplast of trypanosomes, minicircles encode guide RNAs for RNA editing. In ''Amphidinium'', the chloroplast genome is made of minicircles that encode chloroplast proteins. ''In vitro'' experimentally-derived minicircles Minicircles are small (~4kb) circular plasmid derivatives that have been freed from all prokaryotic vector parts. They have been applied as transgene carriers for the genetic modification of mammalian cells, with the advantage that, since they contain no bacterial DNA sequences, they are less likely to be perceived as foreign and destroyed. (Typical transgene delivery methods involve plasmids, which contain foreign DNA.) The smaller size of minicircles also extends their cloning capacity and facilitates their delivery into cells. Their preparation usually follows a two-step procedure: * production of a 'parental plas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guide RNA
A guide RNA (gRNA) is a piece of RNA that functions as a guide for RNA- or DNA-targeting enzymes, with which it forms complexes. Very often these enzymes will delete, insert or otherwise alter the targeted RNA or DNA. They occur naturally, serving important functions, but can also be designed to be used for targeted editing, such as with CRISPR-Cas9 and CRISPR-Cas12. History RNA-editing Guide RNA was discovered in 1990 by B. Blum, N. Bakalara, and L. Simpson in the mitochondria of protists called Leishmania tarentolae. The guide RNA there is encoded in maxicircle DNA and contains sequences matching those within the edited regions of the mRNA. They enable the cleavage, insertion and deletion of bases. Guide RNA in Protists Trypanosomatid protists and other kinetoplastids have a novel post-transcriptional mitochondrial RNA modification process known as "RNA editing". They have a large segment of highly organized DNA segments in their mitochondria. This mitochondrial DNA is circul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catenation
In chemistry, catenation is the bonding of atoms of the same element into a series, called a ''chain''. A chain or a ring shape may be ''open'' if its ends are not bonded to each other (an open-chain compound), or ''closed'' if they are bonded in a ring (a cyclic compound). The words ''to catenate'' and ''catenation'' reflect the Latin root '' catena'', "chain". Carbon Catenation occurs most readily with carbon, which forms covalent bonds with other carbon atoms to form longer chains and structures. This is the reason for the presence of the vast number of organic compounds in nature. Carbon is most well known for its properties of catenation, with organic chemistry essentially being the study of catenated carbon structures (and known as catenae). Carbon chains in biochemistry combine any of various other elements, such as hydrogen, oxygen, and biometals, onto the backbone of carbon. However, carbon is by no means the only element capable of forming such catenae, and several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
