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Shigella
''Shigella'' is a genus of bacteria that is Gram-negative, facultative anaerobic, non-spore-forming, nonmotile, rod-shaped, and genetically closely related to ''E. coli''. The genus is named after Kiyoshi Shiga, who first discovered it in 1897. The causative agent of human shigellosis, ''Shigella'' causes disease in primates, but not in other mammals. It is only naturally found in humans and gorillas. During infection, it typically causes dysentery. ''Shigella'' is one of the leading bacterial causes of diarrhea worldwide, causing an estimated 80–165 million cases. The number of deaths it causes each year is estimated at between 74,000 and 600,000. It is one of the top four pathogens that cause moderate-to-severe diarrhea in African and South Asian children. Classification ''Shigella'' species are classified by three serogroups and one serotype: * Serogroup ''A'': '' S. dysenteriae'' (15 serotypes) * Serogroup ''B'': '' S. flexneri'' (9 serotypes) * Serogroup ''C'': '' S. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigellosis
Shigellosis is an infection of the intestines caused by ''Shigella'' bacteria. Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. The diarrhea may be bloody. Symptoms typically last five to seven days and it may take several months before bowel habits return entirely to normal. Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome. Shigellosis is caused by four specific types of ''Shigella''. These are typically spread by exposure to infected feces. This can occur via contaminated food, water, or hands or sexual contact. Contamination may be spread by flies or when changing diapers (nappies). Diagnosis is by stool culture. The risk of infection can be reduced by properly washing the hands. There is no vaccine. Shigellosis usually resolves without specific treatment. Rest, and sufficient fluids by mouth, are recommended. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigella Sonnei
''Shigella sonnei'' is a species of ''Shigella''. Together with ''Shigella flexneri'', it is responsible for 90% of shigellosis cases. ''Shigella sonnei'' is named for the Danish bacteriologist Carl Olaf Sonne. It is a Gram-negative, rod-shaped, nonmotile, non-spore-forming bacterium. Pathophysiology This species polymerizes host cell actin. Evolution This species is clonal and has spread worldwide. Analysis of 132 strains has shown that they originated from a common ancestor in Europe around 1500 AD. Causes "Group D" ''Shigella'' bacteria cause shigellosis. Those infected with the bacteria release it into their stool, thus causing possibility of spread through food or water, or from direct contact to a person orally. Having poorly sanitized living conditions or contaminated food or water contributes to contracting the disease. People at risk Infants and toddlers, the elderly, and people living with chronic health conditions are all susceptible to the most severe symptoms of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigella Boydii
''Shigella boydii'' is a Gram-negative bacterium of the genus ''Shigella''. Like other members of the genus, ''S. boydii'' is a nonmotile, nonsporeforming, rod-shaped bacterium which can cause dysentery in humans through fecal-oral contamination. ''Shigella boydii'' is the most genetically divergent species of the genus ''Shigella''. There are 19 known serotypes of ''Shigella boydii''. ''S. boydii'' is restricted to the Indian subcontinent. The species is named after the British bacteriologist John Boyd. Sequenced genomes *''Shigella boydii'' strain BS512 (serotype 18; group 1) has one chromosome and five plasmids. References External links''Shigella boydii'' Genome Project Page— by Entrez The Entrez (pronounced ''ɒnˈtreɪ'') Global Query Cross-Database Search System is a federated search engine, or web portal that allows users to search many discrete health sciences databases at the National Center for Biotechnology Information ... *Type strain of ''Shigella ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verotoxin
Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, expressed by genes considered to be part of the genome of lambdoid prophages. The toxins are named after Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by '' Shigella dysenteriae''. Shiga-like toxin (SLT) is a historical term for similar or identical toxins produced by ''Escherichia coli''. The most common sources for Shiga toxin are the bacteria ''S. dysenteriae'' and some serotypes of ''Escherichia coli'' (STEC), which includes serotypes O157:H7, and O104:H4. Nomenclature Microbiologists use many terms to describe Shiga toxin and differentiate more than one unique form. Many of these terms are used interchangeably. # Shiga toxin type 1 and type 2 (Stx-1 and 2) are the Shiga toxins produced by some'' E. coli'' strains. Stx-1 is identical to Stx of ''Shigella spp.'' or differs by only one amino acid. Stx-2 shares 56% sequence identity with Stx-1. # Cytot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shiga Toxin
Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, expressed by genes considered to be part of the genome of lambdoid prophages. The toxins are named after Kiyoshi Shiga, who first described the bacterial origin of dysentery caused by ''Shigella dysenteriae''. Shiga-like toxin (SLT) is a historical term for similar or identical toxins produced by ''Escherichia coli''. The most common sources for Shiga toxin are the bacteria ''S. dysenteriae'' and some serotypes of ''Escherichia coli'' (STEC), which includes serotypes O157:H7, and O104:H4. Nomenclature Microbiologists use many terms to describe Shiga toxin and differentiate more than one unique form. Many of these terms are used interchangeably. # Shiga toxin type 1 and type 2 (Stx-1 and 2) are the Shiga toxins produced by some'' E. coli'' strains. Stx-1 is identical to Stx of ''Shigella spp.'' or differs by only one amino acid. Stx-2 shares 56% sequence identity with Stx-1. # Cytotoxin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia
''Escherichia'' () is a genus of Gram-negative, non- spore-forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, ''Escherichia'' species provide a portion of the microbially derived vitamin K for their host. A number of the species of ''Escherichia'' are pathogenic. The genus is named after Theodor Escherich, the discoverer of ''Escherichia coli''. ''Escherichia'' are facultative aerobes, with both aerobic and anaerobic growth, and an optimum temperature of 37 °C. ''Escherichia'' are usually motile by flagella, produce gas from fermentable carbohydrates, and do not decarboxylate lysine or hydrolyze arginine. Species include '' E. albertii'', '' E. fergusonii'', '' E. hermannii'', '' E. marmotae'' and most notably, the model organism and clinically relevant '' E. coli''. '' Shimwellia blattae'' was formerly classified in this genus. Pathogenesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetics
In biology, phylogenetics (; from Greek language, Greek wikt:φυλή, φυλή/wikt:φῦλον, φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, Protein, protein Amino acid, amino acid sequences, or Morphology (biology), morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the tiger cowry of the Indo-Pacific, ''Cypraea'' (''Cypraea'') ''tigris'' Linnaeus, which belongs to the subgenus ''Cypraea'' of the genus ''Cypraea''. However, it is not mandatory, or even customary, when giving the name of a species, to include the subgeneric name. In the International Code of Nomenclature for algae, fungi, and plants (ICNafp), the subgenus is one of the possible subdivisions of a genus. There is no limit to the number of divisions that are permitted within a genus by adding the prefix "sub-" or in other ways as long as no confusion can result. Article 4 The secondary ranks of section and series are subordinate to subgenus. An example is ''Banksia'' subg. ''Isostylis'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrograph
A micrograph or photomicrograph is a photograph or digital image taken through a microscope or similar device to show a magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a microscope but is only slightly magnified, usually less than 10 times. Micrography is the practice or art of using microscopes to make photographs. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are widely used in all fields of microscopy. Types Photomicrograph A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to as ''photomicroscopy''. At a basic level, photomicroscopy may be performed simply by connecting a camera to a microscope, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fecal–oral Route
The fecal–oral route (also called the oral–fecal route or orofecal route) describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal–oral disease transmission include lack of adequate sanitation (leading to open defecation), and poor hygiene practices. If soil or water bodies are polluted with fecal material, humans can be infected with waterborne diseases or soil-transmitted diseases. Fecal contamination of food is another form of fecal-oral transmission. Washing hands properly after changing a baby's diaper or after performing anal hygiene can prevent foodborne illness from spreading. The common factors in the fecal-oral route can be summarized as five Fs: fingers, flies, fields, fluids, and food. Diseases caused by fecal-oral transmission include typhoid, cholera, polio, hepatitis and many other infections, especially ones that cause diarrhea. Background Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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