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AB5 Toxins
The AB5 toxins are six-component protein complexes secreted by certain pathogenic bacteria known to cause human diseases such as cholera, dysentery, and hemolytic–uremic syndrome. One component is known as the A subunit, and the remaining five components are B subunits. All of these toxins share a similar structure and mechanism for entering targeted host cells. The B subunit is responsible for binding to receptors to open up a pathway for the A subunit to enter the cell. The A subunit is then able to use its catalytic machinery to take over the host cell's regular functions. Families There are four main families of the AB5 toxin. These families are characterized by the sequence of their A (catalytic) subunit, as well as their catalytic activity. Cholera toxin This family is also known as Ct or Ctx, and also includes the heat-labile enterotoxin, known as LT. Cholera toxin's discovery is credited by many to Dr. Sambhu Nath De. He conducted his research in Calcutta (now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal. The most common cause is an infection of the intestines due to either a virus, bacterium, or parasite—a condition also known as gastroenteritis. These infections are often acquired from food or water that has been contaminated by feces, or directly from another person who is infected. The three types of diarrhea are: short duration watery diarrhea, short duration bloody diarrhea, and persistent diarrhea (lasting more than two weeks, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacillus Anthracis
''Bacillus anthracis'' is a gram-positive and rod-shaped bacterium that causes anthrax, a deadly disease to livestock and, occasionally, to humans. It is the only permanent ( obligate) pathogen within the genus ''Bacillus''. Its infection is a type of zoonosis, as it is transmitted from animals to humans. It was discovered by a German physician Robert Koch in 1876, and became the first bacterium to be experimentally shown as a pathogen. The discovery was also the first scientific evidence for the germ theory of diseases. ''B. anthracis'' measures about 3 to 5 μm long and 1 to 1.2 μm wide. The reference genome consists of a 5,227,419 bp circular chromosome and two extrachromosomal DNA plasmids, pXO1 and pXO2, of 181,677 and 94,830 bp respectively, which are responsible for the pathogenicity. It forms a protective layer called endospore by which it can remain inactive for many years and suddenly becomes infective under suitable environmental conditions. Because of the resilie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Protease
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like. Classification The MEROPS protease classification system counts 16 superfamilies (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. The majority belong to the S1 family of the PA clan (superfamily) of proteases. For superfamilies, P: superfamily, containing a mixture of nucleophile class families, S: purely serine proteases. superfamily. Within each superfamily, families are designated by their catalytic nucleophile, (S: serine proteases). Substrate specificity Serine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locus Of Enterocyte Effacement
The locus of enterocyte effacement (LEE) is a moderately conserved pathogenicity island consisting of 35,000 base pairs in the bacteria ''Escherichia coli'' genome. The LEE encodes the Type III secretion system and associated chaperones and effector proteins responsible for attaching and effacing (AE) lesions in the large intestine. These proteins include intimin, Tir, EspC, EspF, EspH, and Map protein. The LEE has a 38% G+C ratio. See also *Locus of enterocyte effacement-encoded regulator The locus of enterocyte effacement-encoded regulator (Ler) is a regulatory protein that controls bacterial pathogenicity of enteropathogenic ''Escherichia coli'' (EPEC) and enterohemorrhagic ''Escherichia coli'' (EHEC). More specifically, Ler regu ... Cell biology {{microbiology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kiyoshi Shiga
was a Japanese physician and bacteriologist. He had a well-rounded education and career that led to many scientific discoveries. In 1897, Shiga was credited with the discovery and identification of the ''Shigella'' ''dysenteriae'' microorganism which causes dysentery, and the Shiga toxin which is produced by the bacteria. He conducted research on other diseases such as tuberculosis and trypanosomiasis, and made many advancements in bacteriology and immunology. Personal life Shiga was born in Sendai, Miyagi Prefecture. His original surname was Satō, but he changed it to his mother's maiden name, Shiga, after being brought up by his maternal family. Shiga was raised during Japan's Industrial age and restoration. The changing times put financial troubles on his family. In 1900, Kiyoshi Shiga married Ichiko Shiga and in the following years had eight children. He faced many family hardships. Shiga lost his wife in 1944 to stomach cancer, his eldest son to turbulent seas during a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colitis
Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification) is used if: * The cause of the inflammation in the colon is undetermined; for example, ''colitis'' may be applied to ''Crohn's disease'' at a time when the diagnosis is unknown, or * The context is clear; for example, an individual with ulcerative colitis is talking about their disease with a physician who knows the diagnosis. Signs and symptoms The signs and symptoms of colitis are quite variable and dependent on the cause of the given colitis and factors that modify its course and severity. Common symptoms of colitis may include: mild to severe abdominal pains and tenderness (depending on the stage of the disease), persistent hemorrhagic diarrhea with pus either present or absent in the stools, fecal incontinence, flatulence, fatigu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigella Dysenteriae
''Shigella dysenteriae'' is a species of the rod-shaped bacterial genus ''Shigella''. ''Shigella'' species can cause shigellosis ( bacillary dysentery). Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. ''S. dysenteriae'' has the ability to invade and replicate in various species of epithelial cells and enterocytes. Epidemiology Shigella infections may be contracted by a lack of monitoring of water and food quality, unsanitary cooking conditions and improper hygiene practices. ''S. dysenteriae'' spreads through contaminated water and food, causes minor dysentery because of its Shiga toxin, but other species may also be dysentery agents. ''S. dysenteriae'' releases an exotoxin that compromises the gut and central nervous system. If acting as an enterotoxin, diarrhea will occur. When acting as a neurotoxin, severe cases of shigellosis are developed, inducing comas and meningismus. Contamination is often caused by bacteria on unwashed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octave Gengou
Octave Gengou (27 February 1875, Ouffet – 25 April 1957, Brussels) was a Belgian bacteriologist. He researched with Jules Bordet the ''Bordetella pertussis'' bacteria. Biography At the age of 22, he obtained his doctorate at the University of Liège, later being named as deputy director at the Pasteur Institute of Brabant. In 1945, he became professor emeritus at the University of Brussels.ARMB; Royal Academy of Medicine of Belgium biographical information Gengou worked at the Belgium in . With |
Jules Bordet
Jules Jean Baptiste Vincent Bordet (; 13 June 1870 – 6 April 1961) was a Belgian immunologist and microbiologist. The bacterial genus ''Bordetella'' is named after him. The Nobel Prize in Physiology or Medicine was awarded to him in 1919 for his discoveries relating to immunity. Education and early life Bordet was born at Soignies, Belgium. He graduated as Doctor of Medicine from the Free University of Brussels in 1892 and began his work at the Pasteur Institute in Paris in 1894, in the laboratory of Elie Metchnikoff, who had just discovered phagocytosis of bacteria by white blood cells, an expression of cellular immunity. Career In 1895 Bordet made his discovery that the bacteriolytic effect of acquired specific antibody is significantly enhanced ''in vivo'' by the presence of innate serum components which he termed alexine (but which are now known as complement). Four years later, in 1899, he described a similar destructive process involving complement, "hemolysis", in w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paroxysmal Attack
Paroxysmal attacks or paroxysms (from Greek παροξυσμός) are a sudden recurrence or intensification of symptoms, such as a spasm or seizure. These short, frequent symptoms can be observed in various clinical conditions. They are usually associated with multiple sclerosis or pertussis, but they may also be observed in other disease, disorders such as encephalitis, head Physical trauma, trauma, stroke, asthma, trigeminal neuralgia, breath-holding spells, epilepsy, malaria, tabes dorsalis, and Behçet's disease, paroxysmal nocturnal hemoglobinuria (PNH). It has also been noted as a symptom of gratification disorder in children. The word wikt:paroxysm, paroxysm means "sudden attack, outburst", and comes from the Greek language, Greek παροξυσμός (''paroxusmos''), "irritation, exasperation". [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
