|
Spot 42 RNA
Spot 42 (''spf'') RNA is a regulatory non-coding bacterial small RNA encoded by the spf (spot forty-two) gene. ''Spf'' is found in gammaproteobacteria and the majority of experimental work on Spot42 has been performed in ''Escherichia coli'' and recently in ''Aliivibrio salmonicida''. In the cell Spot42 plays essential roles as a regulator in carbohydrate metabolism and uptake, and its expression is activated by glucose, and inhibited by the cAMP- CRP complex. The sRNA is transcribed from a separate promoter and binds to messenger RNA targets through imperfect base pairing. The half-life of Spot42 ''in vivo'' is 12 to 13 minutes at 37 °C. When grown in media supplemented with glucose, each cell contains 100–200 Spot42 copies. The corresponding level is however reduced 3–4-fold when cells are grown in succinate or when cAMP is added to cells grown in glucose. Discovery Spot42 was first described in 1973 as an unstable RNA species of 109 nucleotides in ''Escherichia c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Structure
Protein secondary structure is the three dimensional form of ''local segments'' of proteins. The two most common secondary structural elements are 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 folds into its three dimensional tertiary structure. Secondary structure is formally defined by the pattern of hydrogen bonds between the amino hydrogen and carboxyl oxygen atoms in the peptide backbone. Secondary structure may alternatively be defined based on the regular pattern of backbone 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 Linderstrøm-Lang at Stanford in 1952. Other types of biopolymers such as nucleic acids also possess characteristic secondary structures. Types The most common secondary st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Succinate
Succinic acid () is a dicarboxylic acid with the chemical formula (CH2)2(CO2H)2. The name derives from Latin ''succinum'', meaning amber. In living organisms, succinic acid takes the form of an anion, succinate, which has multiple biological roles as a metabolic intermediate being converted into fumarate by the enzyme succinate dehydrogenase in complex 2 of the electron transport chain which is involved in making ATP, and as a signaling molecule reflecting the cellular metabolic state. It is marketed as food additive E363. Succinate is generated in mitochondria via the tricarboxylic acid cycle (TCA). Succinate can exit the mitochondrial matrix and function in the cytoplasm as well as the extracellular space, changing gene expression patterns, modulating epigenetic landscape or demonstrating hormone-like signaling. As such, succinate links cellular metabolism, especially ATP formation, to the regulation of cellular function. Dysregulation of succinate synthesis, and therefore A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAMP Receptor Protein
cAMP receptor protein (CRP; also known as catabolite activator protein, CAP) is a regulatory protein in bacteria. CRP protein binds cAMP, which causes a conformational change that allows CRP to bind tightly to a specific DNA site in the promoters of the genes it controls. CRP then activates transcription through direct protein–protein interactions with RNA polymerase. The genes regulated by CRP are mostly involved in energy metabolism, such as galactose, citrate, or the PEP group translocation system. In '' Escherichia coli'', cyclic AMP receptor protein (CRP) can regulate the transcription of more than 100 genes. The signal to activate CRP is the binding of cyclic AMP. Binding of cAMP to CRP leads to a long-distance signal transduction from the N-terminal cAMP-binding domain to the C-terminal domain of the protein, which is responsible for interaction with specific sequences of DNA. At "Class I" CRP-dependent promoters, CRP binds to a DNA site located upstream of core ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterobacteriaceae
Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Pseudomonadota. In 2016, the description and members of this family were emended based on comparative genomic analyses by Adeolu et al. Enterobacteriaceae includes, along with many harmless symbionts, many of the more familiar pathogens, such as '' Salmonella'', ''Escherichia coli'', '' Klebsiella'', and '' Shigella''. Other disease-causing bacteria in this family include '' Enterobacter'' and '' Citrobacter''. Members of the Enterobacteriaceae can be trivially referred to as enterobacteria or "enteric bacteria",as several members live in the intestines of animals. In fact, the etymology of the family is enterobacterium with the suffix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yersinia
''Yersinia'' is a genus of bacteria in the family Yersiniaceae. ''Yersinia'' species are Gram-negative, coccobacilli bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of ''Yersinia'' are pathogenic in humans; in particular, '' Y. pestis'' is the causative agent of the plague. Rodents are the natural reservoirs of ''Yersinia''; less frequently, other mammals serve as the host. Infection may occur either through blood (in the case of ''Y. pestis'') or in an alimentary fashion, occasionally via consumption of food products (especially vegetables, milk-derived products, and meat) contaminated with infected urine or feces. Speculations exist as to whether or not certain ''Yersinia'' can also be spread by protozoonotic mechanisms, since ''Yersinia'' species are known to be facultative intracellular parasites; studies and discussions of the possibility of amoeba-vectored (through the cyst form of the protozoan) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella
''Salmonella'' is a genus of rod-shaped (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two species of ''Salmonella'' are ''Salmonella enterica'' and '' Salmonella bongori''. ''S. enterica'' is the type species and is further divided into six subspecies that include over 2,600 serotypes. ''Salmonella'' was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon. ''Salmonella'' species are non-spore-forming, predominantly motile enterobacteria with cell diameters between about 0.7 and 1.5 μm, lengths from 2 to 5 μm, and peritrichous flagella (all around the cell body, allowing them to move). They are chemotrophs, obtaining their energy from oxidation and reduction reactions, using organic sources. They are also facultative anaerobes, capable of generating ATP with oxygen ("aerobically") when it is available, or using other electron acceptors or fermentation ("anaerobically") when oxygen is not available. ''Salmonella'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klebsiella
''Klebsiella'' is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule. ''Klebsiella'' species are found everywhere in nature. This is thought to be due to distinct sublineages developing specific niche adaptations, with associated biochemical adaptations which make them better suited to a particular environment. They can be found in water, soil, plants, insects and other animals including humans. ''Klebsiella'' is named after German-Swiss microbiologist Edwin Klebs (1834–1913). Carl Friedlander described ''Klebsiella'' bacillus which is why it was termed Friedlander bacillus for many years. The members of the genus ''Klebsiella'' are a part of the human and animal's normal flora in the nose, mouth and intestines. The species of ''Klebsiella'' are all gram-negative and usually non-motile. They tend to be shorter and thicker when compared to others in the family Enterobacteriaceae. The cells are rods in shape and gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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'': '' ... [...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 While ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5S RRNA
The 5S ribosomal RNA (5S rRNA) is an approximately 120 nucleotide-long ribosomal RNA molecule with a mass of 40 kDa. It is a structural and functional component of the large subunit of the ribosome in all domains of life (bacteria, archaea, and eukaryotes), with the exception of mitochondrial ribosomes of fungi and animals. The designation 5S refers to the molecule's sedimentation velocity in an ultracentrifuge, which is measured in Svedberg units (S). Biosynthesis In prokaryotes, the 5S rRNA gene is typically located in the rRNA operons downstream of the small and the large subunit rRNA, and co-transcribed into a polycistronic precursor. A particularity of eukaryotic nuclear genomes is the occurrence of multiple 5S rRNA gene copies (5S rDNA) clustered in tandem repeats, with copy number varying from species to species. Eukaryotic 5S rRNA is synthesized by RNA polymerase III, whereas other eukaryotic rRNAs are cleaved from a 45S precursor transcribed by RNA polymerase I. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrophoretic Mobility
Electrophoresis, from Ancient Greek ἤλεκτρον (ḗlektron, "amber") and φόρησις (phórēsis, "the act of bearing"), is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. Electrophoresis of positively charged particles (cations) is sometimes called cataphoresis, while electrophoresis of negatively charged particles (anions) is sometimes called anaphoresis. The electrokinetic phenomenon of electrophoresis was observed for the first time in 1807 by Russian professors Peter Ivanovich Strakhov and Ferdinand Frederic Reuss at Moscow University, who noticed that the application of a constant electric field caused clay particles dispersed in water to migrate. It is ultimately caused by the presence of a charged interface between the particle surface and the surrounding fluid. It is the basis for analytical techniques used in chemistry for separating molecules by size, charge, or binding affinity. Electrop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Salmonella")
