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Corynebacterium
''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name ('' coryneform'' means "club-shaped"). They are widely distributed in nature in the microbiota of animals (including the human microbiota) and are mostly innocuous, most commonly existing in commensal relationships with their hosts. Some, such as '' C. glutamicum'', are commercially and industrially useful. Others can cause human disease, including, most notably, diphtheria, which is caused by '' C. diphtheriae''. Like various species of microbiota (including their relatives in the genera '' Arcanobacterium'' and '' Trueperella''), they are usually not pathogenic, but can occasionally capitalize opportunistically on atypical access to tissues (via wounds) or weakened host defenses. Taxonomy The genus ''Corynebacterium'' was created by Lehmann and Neumann in 18 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corynebacterium Diphtheriae
''Corynebacterium diphtheriae'' is a Gram-positive pathogenic bacterium that causes diphtheria. It is also known as the Klebs–Löffler bacillus because it was discovered in 1884 by German bacteriologists Edwin Klebs (1834–1912) and Friedrich Löffler (1852–1915). These bacteria are usually harmless, unless they are infected by a bacteriophage carrying a gene which gives rise to a microbial toxin, toxin. This toxin causes the disease. Diphtheria is caused by the adhesion and infiltration of the bacteria into the mucosal layers of the body, primarily affecting the respiratory tract and causing the subsequent release of an exotoxin. The toxin has a localized effect on skin lesions, as well as a metastatic, proteolytic effects on other organ systems in severe infections. Originally a major cause of childhood mortality, diphtheria has been almost entirely eradicated due to the vigorous administration of the diphtheria vaccination in the 1910s. Diphtheria is no longer transmitted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corynebacterium Ulcerans
''Corynebacterium ulcerans'' is a rod-shaped, aerobic, and Gram-positive bacterium. Most ''Corynebacterium'' species are harmless, but some cause serious illness in humans, especially in immunocompromised humans. ''C. ulcerans'' has been known to cause diphtheria and diphtheria-like infections in patients. Previously thought to simply be contaminants recovered from diphtheria patients, “ coryneform” or “diphtheroids” are now believed to be the ''cause'' of such infections. Disease Increasingly over the past few decades, ''C. ulcerans'' has been recognized as an emerging pathogen in over six countries across the globe including the United States, the United Kingdom, and Japan. '' C. diphtheriae'' is the causative agent of classical diphtheria, and ''C. ulcerans'' has been found to carry the same gene that codes for the diphtheria toxin. After swabbing lesions on a 53-year-old woman in Germany who experienced swelling of her pharynx and who developed a whitish pseudomem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corynebacterium Glutamicum
''Corynebacterium glutamicum'' is a Gram-positive, rod-shaped bacterium that is used industrially for large-scale production of amino acids, especially glutamic acid and lysine. While originally identified in a screen for organisms secreting L-glutamate, mutants of ''C. glutamicum'' have also been identified that produce various other amino acids and derivatives of amino acids. Due to its industrial importance, several clones of ''C. glutamicum'' have been sequenced by both industry and academic groups. Furthermore, small RNA data was obtained by RNA-Seq in ''C. glutamicum'' ATCC 13032. The metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ... of this strain has been reconstructed and is available in the form of a genome-scale metabolic model. See also * List of seque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphtheria
Diphtheria is an infection caused by the bacteria, bacterium ''Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild Course (medicine), clinical course, but in some outbreaks, the mortality rate approaches 10%. Signs and symptoms may vary from mild to severe, and usually start two to five days after exposure. Symptoms often develop gradually, beginning with a sore throat and fever. In severe cases, a grey or white patch develops in the throat, which can block the airway, and create a barking cough similar to what is observed in croup. The neck may also swell, in part due to the enlargement of the facial lymph nodes. Diphtheria can also involve the skin, eyes, or genitals, and can cause complications, including myocarditis (which in itself can result in an cardiac arrhythmia, abnormal heart rate), peripheral neuropathy, inflammation of nerves (which can result in paralysis), proteinuria, kidney problems, and bleeding problems due to thrombocytopenia, low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Microbiota
Human microbiota are microorganisms (bacteria, viruses, fungi and archaea) found in a specific environment. They can be found in the stomach, intestines, skin, genitals and other parts of the body. Various body parts have diverse microorganisms. Some microbes are specific to certain body parts and others are associated with many microbiomes. This article lists some of the species recognized as belonging to the human microbiome and focuses on the oral, vaginal, ovarian follicle, uterus and the male reproductive tract microbiota. Categories of bacteria The "reference" 70 kg human body is estimated to have around 39 trillion bacteria with a mass of about 0.2 kg. These can be separated into about 10,000 microbial species, about 180 of the most studied is listed below here. However, these can broadly be put into three categories: Spheres or ball-shaped (cocci bacteria) Cocci are usually round or spherical in shape. They can form clusters and are non-motile. Examples incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arcanobacterium
''Arcanobacterium'' () is a genus of bacteria. They are gram-positive, non– acid fast, non motile, facultatively anaerobic, and non–endospore forming. They are widely distributed in nature in the microbiota of animals (including the human microbiota) and are mostly innocuous. Some can cause disease in humans and other animals (for example, ''Arcanobacterium haemolyticum'' infections). As with various species of a microbiota (including their cousins in the genera ''Corynebacterium'' and ''Trueperella''), they usually are not pathogenic but can occasionally opportunistically capitalize on atypical access to tissues (via wounds) or weakened host defenses. Taxonomy As explained by Yassin ''et al''., the genus ''Arcanobacterium'' was first described by Collins ''et al''. in 1982 to accommodate bacterial strains previously assigned to the genus ''Corynebacterium'' variously (and controversially) as ''C. pyogenes hominis'' and then ''C. haemolyticum'', thenceforth to be kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-positive Bacteria
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is used by microbiologists to place bacteria into two main categories, gram-positive (+) and gram-negative (−). Gram-positive bacteria have a thick layer of peptidoglycan within the cell wall, and gram-negative bacteria have a thin layer of peptidoglycan. Gram-positive bacteria retain the crystal violet stain used in the test, resulting in a purple color when observed through an optical microscope. The thick layer of peptidoglycan in the bacterial cell wall retains the stain after it has been fixed in place by iodine. During the decolorization step, the decolorizer removes crystal violet from all other cells. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthrobacter
''Arthrobacter'' (from the Greek, "jointed small stick”) is a genus of bacterium, bacteria that is commonly found in soil. All species in this genus are Gram-positive obligate aerobes that are bacterial shape, rods during exponential growth and bacterial shape, cocci in their Stationary phase (biology), stationary phase. ''Arthrobacter'' have a distinctive method of cell division called "snapping division" or reversion (microbiology), reversion in which the outer bacterial cell wall ruptures at a joint. Description ''Arthrobacter'' can be grown on mineral salts pyridone broth, where colonies have a greenish metallic center on incubated at . Under the microscope, ''Arthrobacter'' appear as rods when rapidly dividing, and cocci when in stationary phase. Dividing cells may also appear as chevrons ("V" shapes). Other notable characteristics are that it can use pyridone as its sole carbon source, and that its cocci are resistant to desiccation and starvation. Use in industry ''Arth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Agar
An agar plate is a Petri dish that contains a growth medium solidified with agar, used to Microbiological culture, culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics. Individual microorganisms placed on the plate will grow into individual colony (biology), colonies, each a cloning, clone genetically identical to the individual ancestor organism (except for the low, unavoidable rate of mutation). Thus, the plate can be used either to estimate the concentration of organisms in a Microbiological culture, liquid culture or a suitable dilution of that culture using a colony counter, or to generate genetically pure cultures from a mixed culture of genetically different organisms. Several methods are available to plate out cells. One technique is known as "Streaking (microbiology), streaking". In this technique, a drop of the culture on the end of a thin, sterilization (microbiology), sterile loop of wire, sometimes known as an inocu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nocardia
''Nocardia'' is a genus of weakly staining Gram-positive, catalase, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments (appearing similar to fungi, but being truly bacteria). It contains a total of 85 species. Some species are nonpathogenic, while others are responsible for nocardiosis. ''Nocardia'' species are found worldwide in soil rich in organic matter. In addition, they are oral microflora found in healthy human Gums, gingiva, as well as periodontal pockets. Most ''Nocardia'' infections are acquired by inhalation of the bacteria or through traumatic introduction through openings in Epithelium, epithelial barriers. Culture and staining ''Nocardia'' colonies have a variable appearance, but most species appear to have aerial hyphae when viewed with a dissecting microscope, particularly when they have been grown on nutritionally limiting media. ''Nocardia'' grow slowly on nonselective culture media, and are strict Aerobic metaboli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacillus (shape)
Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea). Generally, the basic morphologies are spheres (coccus) and round-ended cylinders or rod shaped (bacillus). But, there are also other morphologies such as helically twisted cylinders (example '' Spirochetes''), cylinders curved in one plane (selenomonads) and unusual morphologies (the square, flat box-shaped cells of the Archaean genus '' Haloquadratum)''. Other arrangements include pairs, tetrads, clusters, chains and palisades. Types Coccus A coccus (plural ''cocci'', from the Latin ''coccinus'' (scarlet) and derived from the Greek ''kokkos'' (berry)), is any microorganism (usually bacteria) whose overall shape is spherical or nearly spherical. Coccus refers to the shape of the bacteria and can contain multiple genera, such as st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology (from Ancient Greek μορφή (morphḗ) "form", and λόγος (lógos) "word, study, research") is the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern, size), as well as the form and structure of internal parts like bones and organs, i.e., anatomy. This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of the overall structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fried ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
