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Helicobacter Cetorum
''Helicobacter cetorum'' is a Gram-negative, microaerophilic, spiral (helical) bacterium that is usually found in the stomachs of whales and dolphins. Based on 16S rRNA sequencing, its genome is very similar to that of '' Helicobacter pylori'' in that it can cause gastric disease in these animals. Originally isolated among Atlantic white-sided dolphins and Beluga whales in 2000, ''H. cetorum'' has been associated with hemorrhages throughout its entire gastrointestinal tract, but its role has not yet been discovered. Prior to the discovery of ''H. cetorum'', there have not been any other ''Helicobacter'' species reported in dolphins. Microbiology Morphology ''Helicobacter cetorum'' is a helical, Gram-negative bacteria that is 4 μm long, 0.6 μm wide, and contains a bipolar flagella. It was originally isolated from fecal samples of Atlantic white-sided dolphins and Beluga whales, and the samples were then visualized via electron microscopy and by Gram stain and Stein's s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microaerophile
A microaerophile is a microorganism that requires environments containing lower levels of dioxygen than that are present in the atmosphere (i.e. < 21% O2; typically 2–10% O2) for optimal growth. A more restrictive interpretation requires the microorganism to be obligate in this requirement. Many microaerophiles are also capnophiles, requiring an elevated concentration of (e.g. 10% CO2 in the case of '' Campylobacter'' ). The original definitio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Bacteria
Spiral bacteria, bacteria of spiral (helical) shape, form the third major morphological category of prokaryotes along with the rod-shaped bacilli and round cocci. Spiral bacteria can be subclassified by the number of twists per cell, cell thickness, cell flexibility, and motility. The two types of spiral cells are spirillum and spirochete, with spirillum being rigid with external flagella, and spirochetes being with internal flagella. Spirillum A spirillum (plural spirilla) is a rigid spiral bacterium that is Gram-negative and frequently has external amphitrichous or lophotrichous flagella. Examples include: * Members of the genus ''Spirillum'' * '' Campylobacter'' species, such as ''Campylobacter jejuni'', a foodborne pathogen that causes campylobacteriosis * ''Helicobacter'' species, such as ''Helicobacter pylori'', a cause of peptic ulcers Spirochetes A spirochete (plural spirochetes) is a very thin, elongate, flexible, spiral bacteria that is motile via internal peripla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16S Ribosomal RNA
16 S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as 16S rRNA gene and are used in reconstructing phylogenies, due to the slow rates of evolution of this region of the gene. Carl Woese and George E. Fox were two of the people who pioneered the use of 16S rRNA in phylogenetics in 1977. Multiple sequences of the 16S rRNA gene can exist within a single bacterium. Functions * Like the large (23S) ribosomal RNA, it has a structural role, acting as a scaffold defining the positions of the ribosomal proteins. * The 3-end contains the anti- Shine-Dalgarno sequence, which binds upstream to the AUG start codon on the mRNA. The 3-end of 16S RNA binds to the proteins S1 and S21 which are known to be involved in initiation of protein synthesis * Interacts with 23S, aiding in the binding of the two ribosomal s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicobacter Pylori
''Helicobacter pylori'', previously known as ''Campylobacter pylori'', is a gram-negative, microaerophilic, spiral (helical) bacterium usually found in the stomach. Its helical shape (from which the genus name, helicobacter, derives) is thought to have evolved in order to penetrate the mucoid lining of the stomach and thereby establish infection. The bacterium was first identified in 1982 by the Australian doctors Barry Marshall and Robin Warren. ''H. pylori'' has been associated with cancer of the mucosa-associated lymphoid tissue in the stomach, esophagus, colon, rectum, or tissues around the eye (termed extranodal marginal zone B-cell lymphoma of the cited organ), and of lymphoid tissue in the stomach (termed diffuse large B-cell lymphoma). ''H. pylori'' infection usually has no symptoms but sometimes causes gastritis (stomach inflammation) or ulcers of the stomach or first part of the small intestine. The infection is also associated with the development of cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic White-sided Dolphin
The Atlantic white-sided dolphin (''Lagenorhynchus acutus'') is a distinctively coloured dolphin found in the cool to temperate waters of the North Atlantic Ocean. Description The dolphin is slightly larger than most other oceanic dolphins. It is just over a meter in length at birth, growing to about (males) and (females) at maturity. It weighs 180–230 kg (400- 510 lb) once fully-grown. Females reach sexual maturity at between 6 and 12 years, and males between 7 and 11 years. The gestation period is 11 months and lactation lasts for about 18 months — both typical figures for dolphins. Individuals are known to live for at least 17 years. The key distinguishing feature is the white to pale yellow patch found behind the dorsal fin of the dolphin on each side. This colour variation is unique amongst the mixtures of white, greys and blues of other pelagic cetaceans. The rest of the body's coloration is well demarcated: the chin, throat and belly are white; the flippe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beluga Whale
The beluga whale () (''Delphinapterus leucas'') is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus ''Delphinapterus''. It is also known as the white whale, as it is the only cetacean to regularly occur with this colour; the sea canary, due to its high-pitched calls; and the melonhead, though that more commonly refers to the melon-headed whale, which is an oceanic dolphin. The beluga is adapted to life in the Arctic, with anatomical and physiological characteristics that differentiate it from other cetaceans. Amongst these are its all-white colour and the absence of a dorsal fin, which allows it to swim under ice with ease. It possesses a distinctive protuberance at the front of its head which houses an animal echolocation, echolocation organ called the Melon (whale), melon, which in this species is large and deformable. The beluga's body size is between that of a dolphin and a true ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urease
Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous bacteria, fungi, algae, plants, and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-containing metalloenzymes of high molecular weight. These enzymes catalyze the hydrolysis of urea into carbon dioxide and ammonia: : (NH2)2CO + H2O CO2 + 2NH3 The hydrolysis of urea occurs in two stages. In the first stage, ammonia and carbamic acid are produced. The carbamate spontaneously and rapidly hydrolyzes to ammonia and carbonic acid. Urease activity increases the pH of its environment as ammonia is produced, which is basic. History Its activity was first identified in 1876 by Frédéric Alphonse Musculus as a soluble ferment. In 1926, James B. Sumner, showed that urease is a protein by examining its crystallized form. Sumner's work was the first demonstration that a protein can function as an enzyme and led eventually to the reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalase
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second. Catalase is a tetramer of four polypeptide chains, each over 500 amino acids long. It contains four iron-containing heme groups that allow the enzyme to react with hydrogen peroxide. The optimum pH for human catalase is approximately 7, and has a fairly broad maximum: the rate of reaction does not change appreciably between pH 6.8 and 7.5. The pH optimum for other catalases varies between 4 and 11 depending on the species. The optimum temperature also varies by species. Structure Human catalase forms a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidase
In biochemistry, an oxidase is an enzyme that catalyzes oxidation-reduction reactions, especially one involving dioxygen (O2) as the electron acceptor. In reactions involving donation of a hydrogen atom, oxygen is reduced to water (H2O) or hydrogen peroxide (H2O2). Some oxidation reactions, such as those involving monoamine oxidase or xanthine oxidase, typically do not involve free molecular oxygen. The oxidases are a subclass of the oxidoreductases. Examples An important example is cytochrome c oxidase, the key enzyme that allows the body to employ oxygen in the generation of energy and the final component of the electron transfer chain. Other examples are: * Glucose oxidase * Monoamine oxidase * Cytochrome P450 oxidase * NADPH oxidase * Xanthine oxidase * L-gulonolactone oxidase * Laccase * Lysyl oxidase * Polyphenol oxidase * Sulfhydryl oxidase. This enzyme oxidises thiol groups. Oxidase test In microbiology, the oxidase test is used as a phenotypic characteristic for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nalidixic Acid
Nalidixic acid (tradenames Nevigramon, NegGram, Wintomylon and WIN 18,320) is the first of the synthetic quinolone antibiotics. In a technical sense, it is a naphthyridone, not a quinolone: its ring structure is a 1,8-naphthyridine nucleus that contains two nitrogen atoms, unlike quinoline, which has a single nitrogen atom. Synthetic quinolone antibiotics were discovered by George Lesher and coworkers as a byproduct of chloroquine manufacture in the 1960s; nalidixic acid itself was used clinically, starting in 1967. Nalidixic acid is effective primarily against Gram-negative bacteria, with minor anti-Gram-positive activity. In lower concentrations, it acts in a bacteriostatic manner; that is, it inhibits growth and reproduction. In higher concentrations, it is bactericidal, meaning that it kills bacteria instead of merely inhibiting their growth. It has historically been used for treating urinary tract infections, caused, for example, by ''Escherichia coli'', ''Proteus'', ''Sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalothin
Cefalotin (INN) or cephalothin (USAN) is a first-generation cephalosporin antibiotic. It was the first cephalosporin marketed (1964) and continues to be widely used. It is an intravenously administered agent with a similar antimicrobial spectrum to cefazolin and the oral agent cefalexin Cefalexin, also spelled cephalexin, is an antibiotic that can treat a number of bacterial infections. It kills gram-positive and some gram-negative bacteria by disrupting the growth of the bacterial cell wall. Cefalexin is a beta-lactam antibi .... Cefalotin sodium is marketed as Keflin ( Lilly) and under other trade names.: Cefalotin The compound is a derivative of thiophene-2-acetic acid.. References Cephalosporin antibiotics Eli Lilly and Company brands Thiophenes Acetate esters {{Antibiotic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
