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Cytolethal Distending Toxin
Cytolethal distending toxins (abbreviated CDTs) are a class of Protein trimer, heterotrimeric toxins produced by certain gram-negative bacteria that display DNase activity. These toxins trigger G2/M cell cycle arrest in specific mammalian cell lines, leading to the enlarged or distended cells for which these toxins are named. Affected cells die by apoptosis. Each toxin consists of three distinct subunits named alphabetically in the order that their coding genes appear in the ''cdt operon''. Cytolethal distending toxins are classified as AB toxins, with an active ("A") subunit that directly damages DNA and a binding ("B") subunit that helps the toxin attach to the target cells. CdtB is the active subunit and a Homology (biology), homolog to mammalian DNase I, whereas CdtA and CdtC make up the binding subunit. Cytolethal distending toxins are produced by gram-negative pathogenic bacteria from the phylum ''Pseudomonadota''. Many of these bacteria, including ''Shigella dysenter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Trimer
image:4tsv bio r 250.jpg, thumbnail, 400px, Trimeric form of a TNF-α mutant In biochemistry, a protein trimer is a Macromolecule, macromolecular Complex (chemistry), complex formed by three, usually covalent bond, non-covalently bound, macromolecules like proteins or nucleic acids. A protein trimer often occurs from the assembly of a protein's Protein quaternary structure, quaternary structure. The non-covalent interactions between the Hydrophobe, hydrophobic and Hydrophile, hydrophilic regions on the polypeptides units help to stabilize the quaternary structure. Since a protein trimer is composed of multiple polypeptide subunits, it is considered an oligomer. A homotrimer would be formed by three identical molecules. A heterotrimer would be formed by three different macromolecules. Type II Collagen is an example of homotrimeric protein, while Type I collagen is an AAB-type heterotrimeric protein. An example of viral protein homotrimeric protein is mammarenavirus of Z matrix prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shigella
''Shigella'' is a genus of bacteria that is Gram negative, facultatively anaerobic, non–spore-forming, nonmotile, rod shaped, and is genetically nested within ''Escherichia''. The genus is named after Kiyoshi Shiga, who discovered it in 1897. ''Shigella'' causes disease in primates, but not in other mammals; it is the causative agent of human shigellosis. It is only naturally found in humans and gorillas. During infection, it typically causes dysentery. ''Shigella'' is a leading cause of bacterial diarrhea worldwide, with 80–165 million annual cases (estimated) and 74,000 to 600,000 deaths. 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. boydii'' (19 serotypes) * Serogroup ''D'': '' S. so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campylobacter Jejuni
''Campylobacter jejuni'' is a species of pathogenic bacteria that is commonly associated with poultry, and is also often found in animal feces. This species of microbe is one of the most common causes of food poisoning in Europe and in the US, with the vast majority of cases occurring as isolated events rather than mass outbreaks. Active surveillance through the Foodborne Diseases Active Surveillance Network (FoodNet) indicates that about 20 cases are ''diagnosed'' each year for each 100,000 people in the US, while many more cases are undiagnosed or unreported; the CDC estimates a total of 1.5 million infections every year. The European Food Safety Authority reported 246,571 cases in 2018, and estimated approximately nine million cases of human campylobacteriosis per year in the European Union. In Africa, Asia, and the Middle East, data indicates that ''C. jejuni'' infections are Endemic (epidemiology), endemic. ''Campylobacter'' is a genus of bacteria that is among the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enterocolitis
Enterocolitis is an inflammation of the digestive tract, involving enteritis of the small intestine and colitis of the colon. It may be caused by various infections, with bacteria, viruses, fungi, parasites, or other causes. Common clinical manifestations of enterocolitis are frequent diarrheal defecations, with or without nausea, vomiting, abdominal pain, fever, chills, and alteration of general condition. General manifestations are given by the dissemination of the infectious agent or its toxins throughout the body, or – most frequently – by significant losses of water and minerals, the consequence of diarrhea and vomiting. Signs and symptoms Symptoms of enterocolitis include abdominal pain, diarrhea, nausea, vomiting, fever, and loss of appetite. Cause Among the causal agents of acute enterocolitis are: * bacteria: ''Salmonella'', ''Shigella'', ''Escherichia coli (E. coli)'', '' Campylobacter'' etc. * viruses: enteroviruses, rotaviruses, norovirus, adenoviruses * fungi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campylobacter Upsaliensis
''Campylobacter upsaliensis'' is a gram-negative bacteria in the ''Campylobacter'' genus. ''C. upsaliensis'' is found worldwide, and is a common cause of campylobacteriosis in humans, as well as gastroenteritis in dogs and cats. Human infections are primarily associated with raw or undercooked meat and contaminated water sources, however there is some zoonotic risk associated with the spread from dogs and cats. ''C. upsaliensis'' primarily affects the gastrointestinal tract as it damages gastrointestinal epithelial cells. There are many methods for detecting ''C.upsaliensis'' including PCR and ELISA, however there is no current gold standard in detection techniques. Infection is typically self limiting, however there is antimicrobial therapy available. Cellular morphology and biochemistry ''Campylobacter upsaliensis'' shares the characteristic appearance of other Campylobacter species: it is a curved to spiral, gram-negative rod that displays darting motility. The bacterium ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typhoid Fever
Typhoid fever, also known simply as typhoid, is a disease caused by '' Salmonella enterica'' serotype Typhi bacteria, also called ''Salmonella'' Typhi. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several days. This is commonly accompanied by weakness, abdominal pain, constipation, headaches, and mild vomiting. Some people develop a skin rash with rose colored spots. In severe cases, people may experience confusion. Without treatment, symptoms may last weeks or months. Diarrhea may be severe, but is uncommon. Other people may carry it without being affected, but are still contagious. Typhoid fever is a type of enteric fever, along with paratyphoid fever. ''Salmonella enterica'' Typhi is believed to infect and replicate only within humans. Typhoid is caused by the bacterium ''Salmonella enterica'' subsp. ''enterica'' serovar Typhi growing in the intestines, Peyer's patches, mesen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella Enterica
''Salmonella enterica'' (formerly ''Salmonella choleraesuis'') is a rod-shaped, flagellate, facultative anaerobic, Gram-negative bacterium and a species of the genus ''Salmonella''. It is divided into six subspecies, arizonae (IIIa), diarizonae (IIIb), houtenae (IV), salamae (II), indica (VI), and enterica (I). A number of its serovars are serious human pathogens; many of them are (more specifically) serovars of ''Salmonella enterica'' subsp. ''enterica''. Epidemiology Most cases of salmonellosis are caused by food infected with ''S. enterica'', which often infects cattle and poultry, though other animals such as domestic cats and hamsters have also been shown to be sources of infection in humans. It primarily resides in the intestinal tract of animals and humans and can be found in feedstuff, soil, bedding, litter, and fecal matter. The primary reservoir for the pathogen is poultry and 70% of human cases are attributed to the consumption of contaminated eggs, chicken, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dysentery
Dysentery ( , ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehydration. The cause of dysentery is usually the bacteria from genus '' Shigella'', in which case it is known as shigellosis, or the amoeba '' Entamoeba histolytica''; then it is called amoebiasis. Other causes may include certain chemicals, other bacteria, other protozoa, or parasitic worms. It may spread between people. Risk factors include contamination of food and water with feces due to poor sanitation. The underlying mechanism involves inflammation of the intestine, especially of the colon. Efforts to prevent dysentery include hand washing and food safety measures while traveling in countries of high risk. While the condition generally resolves on its own within a week, drinking sufficient fluids such as oral rehydration solutio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periodontitis
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main cause of tooth loss for adults worldwide. In its more serious form, called periodontitis, the gums can pull away from the tooth, bone can be lost, and the teeth may loosen or fall out. Halitosis (bad breath) may also occur. Periodontal disease typically arises from the development of plaque biofilm, which harbors harmful bacteria such as ''Porphyromonas gingivalis'' and ''Treponema denticola''. These bacteria infect the gum tissue surrounding the teeth, leading to inflammation and, if left untreated, progressive damage to the teeth and gum tissue. Recent meta-analysis have shown that the composition of the oral microbiota and its response to periodontal disease differ between men and women. These differences are particularly notable in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aggregatibacter Actinomycetemcomitans
''Aggregatibacter actinomycetemcomitans'' is a Gram-negative, facultative anaerobe, nonmotile bacterium that is often found in association with localized aggressive periodontitis, a severe infection of the periodontium. It is also suspected to be involved in chronic periodontitis. Less frequently, ''A. actinomycetemcomitans'' is associated with nonoral infections such as endocarditis. Its role in aggressive periodontitis was first discovered by Danish-born periodontist Jørgen Slots, a professor of dentistry and microbiology at the University of Southern California School of Dentistry. 'Bacterium actinomycetem comitans' was first described by Klinger (1912) as coccobacillary bacteria isolated with ''Actinomyces'' from actinomycotic lesions in humans. It was reclassified as ''Actinobacillus actinomycetemcomitans'' by Topley & Wilson (1929) and as ''Haemophilus actinomycetemcomitans'' by Potts ''et al.'' (1985). The species has attracted attention because of its association ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chancroid
Chancroid ( ) is a bacterial sexually transmitted infection characterized by painful sores on the genitalia. Chancroid is known to spread from one individual to another solely through sexual contact. However, there have been reports of accidental infection through the hand. Signs and symptoms These are only local and no systemic manifestations are present. The ulcer characteristically: * Ranges in size dramatically from 3 to 50 mm (1/8 inch to 2 inches) across * Is painful * Has sharply defined, undermined borders * Has irregular or ragged borders, ''described as saucer-shaped''. * Has a base that is covered with a gray or yellowish-gray material * Has a base that bleeds easily if traumatized or scraped * Painful swollen lymph nodes occur in 30–60% of patients. * Dysuria (pain with urination) and dyspareunia (pain with intercourse) in females About half of infected men have only a single ulcer. Women frequently have four or more ulcers, with fewer symptoms. The ul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogens
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time frames, but soil has the longest or most pers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
