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Intimin
Intimin is a virulence factor ( adhesin) of EPEC (''e.g.'' ''E. coli'' O127:H6) and EHEC (''e.g. E. coli'' O157:H7) ''E. coli'' strains. It is an attaching and effacing (A/E) protein, which with other virulence factors is necessary and responsible for enteropathogenic and enterohaemorrhagic diarrhoea. Intimin is expressed on the bacterial cell surface where it can bind to its receptor Tir (Translocated intimin receptor). Tir, along with over 25 other bacterial proteins, is secreted from attaching and effacing ''E. coli'' directly into the cytoplasm of intestinal epithelial cells by a Type three secretion system. Once within the cytoplasm of the host cell, Tir is inserted into the plasma membrane, allowing surface exposure and intimin binding. Tir-intimin interaction mediates tight binding of enteropathogenic and enterohaemorrhagic ''E.coli'' to the intestinal epithelia, resulting in the formation of effacing lesions on intestinal epithelia. The structure of the C-terminal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tir (receptor)
Tir (translocated intimin receptor) is an essential component in the adherence of the enteropathogenic ''Escherichia coli'' (EPEC) and enterohemorraghic ''Escherichia coli'' (EHEC) to the cells lining the small intestine. To aid attachment, both EPEC and EHEC possess the ability to reorganise the host cell actin cytoskeleton via the secretion of virulence factors. These factors are secreted directly into the cells using a Type three secretion system. One of the virulence factors secreted is the Translocated Intimin Receptor (Tir). Tir is a receptor protein encoded by the ''espE'' gene which is located on the locus of enterocyte effacement (LEE) pathogenicity island in EPEC strains. It is secreted into the host cell membranes and acts as a receptor for intimin which is found on the bacterial surface. Once Tir binds intimin, the bacterium is attached to the enterocyte surface. Tir is also a receptor tyrosine kinase (RTK) that initiates its intimate adherence by inserting a hairpin or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenic Escherichia Coli
''Escherichia coli'' ( Anglicized to ; commonly abbreviated ''E. coli'') is a gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms (endotherms). Most ''E. coli'' strains are harmless, but pathogenic varieties cause serious food poisoning, septic shock, meningitis, or urinary tract infections in humans. Unlike normal flora ''E. coli'', the pathogenic varieties produce toxins and other virulence factors that enable them to reside in parts of the body normally not inhabited by ''E. coli'', and to damage host cells. These pathogenic traits are encoded by virulence genes carried only by the pathogens. Introduction ''E. coli'' and related bacteria constitute about 0.1% of gut flora, and fecal–oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells are able to survive outside the body for only a limited amount of time, which makes them ideal indicator organisms to test en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Three Secretion System
Type three secretion system (often written Type III secretion system and abbreviated TTSS or T3SS, also called Injectisome) is a protein appendage found in several Gram-negative bacteria. In pathogenic bacteria, the needle-like structure is used as a sensory probe to detect the presence of eukaryotic organisms and secrete proteins that help the bacteria infect them. The secreted effector proteins are secreted directly from the bacterial cell into the eukaryotic (host) cell, where they exert a number of effects that help the pathogen to survive and to escape an immune response. Overview The term Type III secretion system was coined in 1993. This secretion system is distinguished from at least five other secretion systems found in Gram-negative bacteria. Many animal and plant associated bacteria possess similar T3SSs. These T3SSs are similar as a result of divergent evolution and phylogenetic analysis supports a model in which gram-negative bacteria can transfer the T3SS gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virulence Factor
Virulence factors (preferably known as pathogenicity factors or effectors in plant science) are cellular structures, molecules and regulatory systems that enable microbial pathogens (bacteria, viruses, fungi, and protozoa) to achieve the following: * colonization of a niche in the host (this includes movement towards and attachment to host cells) * immunoevasion, evasion of the host's immune response * immunosuppression, inhibition of the host's immune response (this includes leukocidin-mediated cell death) * entry into and exit out of cells (if the pathogen is an intracellular one) * obtain nutrition from the host Specific pathogens possess a wide array of virulence factors. Some are chromosomally encoded and intrinsic to the bacteria (e.g. capsules and endotoxin), whereas others are obtained from mobile genetic elements like plasmids and bacteriophages (e.g. some exotoxins). Virulence factors encoded on mobile genetic elements spread through horizontal gene transfer, and can co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta sheets, though beta turns and omega loops occur as well. Secondary structure elements typically spontaneously form as an intermediate before the protein protein folding, folds into its three dimensional protein tertiary structure, tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the Amine, amino hydrogen and carboxyl oxygen atoms in the peptide backbone chain, backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone Dihedral angle#Dihedral angles of proteins, dihedral angles in a particular region of the Ramachandran plot regardless of whether it has the correct hydrogen bonds. The concept of secondary structure was first introduced by Kaj Ulrik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yersinia Enterocolitica
''Yersinia enterocolitica'' is a Gram-negative, bacillus-shaped bacterium, belonging to the family Yersiniaceae. It is motile at temperatures of 22–29° C (72–84 °F), but becomes nonmotile at normal human body temperature. ''Y. enterocolitica'' infection causes the disease yersiniosis, which is an animal-borne disease occurring in humans, as well as in a wide array of animals such as cattle, deer, pigs, and birds. Many of these animals recover from the disease and become carriers; these are potential sources of contagion despite showing no signs of disease. The bacterium infects the host by sticking to its cells using trimeric autotransporter adhesins. The genus ''Yersinia'' includes 20 species: '' Y. aldovae'', '' Y. aleksiciae'', '' Y. bercovieri'', '' Y. canariae'', ''Y. enterocolitica'', '' Y. entomophaga'', '' Y. frederiksenii'', '' Y. hibernica'', '' Y. intermedia'', '' Y. kristensenii'', '' Y. massiliensis'', '' Y. mollaretii'', '' Y. nurmii'', '' Y. pekkanenii'', '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yersinia Pseudotuberculosis
''Yersinia pseudotuberculosis'' is a Gram-negative bacterium that causes Far East scarlet-like fever in humans, who occasionally get infected zoonotically, most often through the food-borne route. Animals are also infected by ''Y. pseudotuberculosis''. The bacterium is urease positive. Pathogenesis In animals, ''Y. pseudotuberculosis'' can cause tuberculosis-like symptoms, including localized tissue necrosis and granulomas in the spleen, liver, and lymph nodes. In humans, symptoms of Far East scarlet-like fever are similar to those of infection with ''Yersinia enterocolitica'' (fever and right-sided abdominal pain), except that the diarrheal component is often absent, which sometimes makes the resulting condition difficult to diagnose. ''Y. pseudotuberculosis'' infections can mimic appendicitis, especially in children and younger adults, and, in rare cases, the disease may cause skin complaints (erythema nodosum), joint stiffness and pain (reactive arthritis), or spread of bac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Invasin
Invasins are a class of proteins associated with the penetration of pathogens into host cells. Invasins play a role in promoting entry during the initial stage of infection. In 2007, Als3 was identified as a fungal invasion allowing ''Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is us ...'' to infect host cells. References External links * Proteins Virulence factors {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Domain
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of several domains, and a domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. In general, domains vary in length from between about 50 amino acids up to 250 amino acids in length. The shortest domains, such as zinc fingers, are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins. Background The concept of the domain was first proposed in 1973 by Wetlaufer aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-terminal
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is translated from messenger RNA, it is created from N-terminus to C-terminus. The convention for writing peptide sequences is to put the C-terminal end on the right and write the sequence from N- to C-terminus. Chemistry Each amino acid has a carboxyl group and an amine group. Amino acids link to one another to form a chain by a dehydration reaction which joins the amine group of one amino acid to the carboxyl group of the next. Thus polypeptide chains have an end with an unbound carboxyl group, the C-terminus, and an end with an unbound amine group, the N-terminus. Proteins are naturally synthesized starting from the N-terminus and ending at the C-terminus. Function C-terminal retention signals While the N-terminus of a protein often cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterohaemorrhagic
Shigatoxigenic ''Escherichia coli'' (STEC) and verotoxigenic ''E. coli'' (VTEC) are strains of the bacterium ''Escherichia coli'' that produce Shiga toxin (or verotoxin). Only a minority of the strains cause illness in humans. The ones that do are collectively known as enterohemorrhagic ''E. coli'' (EHEC) and are major causes of foodborne illness. When infecting the large intestine of humans, they often cause gastroenteritis, enterocolitis, and bloody diarrhea (hence the name "enterohemorrhagic") and sometimes cause a severe complication called hemolytic-uremic syndrome (HUS). Cattle is an important natural reservoir for EHEC because the colonised adult ruminants are asymptomatic. This is because they lack vascular expression of the target receptor for Shiga toxins. The group and its subgroups are known by various names. They are distinguished from other strains of intestinal pathogenic ''E. coli'' including enterotoxigenic ''E. coli'' (ETEC), enteropathogenic ''E. coli'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
