Mycobactin

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Molecular model of mycobactin. Mycobactin+Fe.png
Molecular model of mycobactin.

Mycobactin is a siderophore used by members of the genus Mycobacterium to shuttle free extracellular iron ions into the cytoplasm of mycobacterial cells. [1] The pathogen M. tuberculosis can synthesize its own mycobactin for this purpose, however there are other mycobacteria such as M. avium subspecies paratuberculosis that cannot produce this siderophore and thus it must be supplied to cultivate this organism in the lab or in host organism. [2] [3]

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Mycobacterium tuberculosis, also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid. This coating makes the cells impervious to Gram staining, and as a result, M. tuberculosis can appear weakly Gram-positive. Acid-fast stains such as Ziehl–Neelsen, or fluorescent stains such as auramine are used instead to identify M. tuberculosis with a microscope. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs. The most frequently used diagnostic methods for tuberculosis are the tuberculin skin test, acid-fast stain, culture, and polymerase chain reaction.

<i>Mycobacterium</i> Genus of bacteria

Mycobacterium is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy in humans. The Greek prefix myco- means 'fungus', alluding to this genus' mold-like colony surfaces. Since this genus has cell walls with a waxy lipid-rich outer layer that contains high concentrations of mycolic acid, acid-fast staining is used to emphasize their resistance to acids, compared to other cell types.

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<span class="mw-page-title-main">Ziehl–Neelsen stain</span> Bacteriological technique

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<span class="mw-page-title-main">Phagosome</span>

In cell biology, a phagosome is a vesicle formed around a particle engulfed by a phagocyte via phagocytosis. Professional phagocytes include macrophages, neutrophils, and dendritic cells (DCs).

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Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontuberculous mycobacteria. These bacteria cause Mycobacterium avium-intracellulare infections or Mycobacterium avium complex infections in humans. These bacteria are common and are found in fresh and salt water, in household dust and in soil. MAC bacteria usually cause infection in those who are immunocompromised or those with severe lung disease.

<i>Mycobacterium kansasii</i> Species of bacterium

Mycobacterium kansasii is a bacterium in the Mycobacterium genus. It is an environmental bacteria that causes opportunistic infections in humans, and is one of the leading mycobacterial causes of human disease after tuberculosis and leprosy.

Mycobacterium vaccae is a nonpathogenic species of the Mycobacteriaceae family of bacteria that lives naturally in soil. Its name originates from the Latin word, vacca (cow), since the first Mycobacterium strain was cultured from cow dung in Austria. Mycobacterium vaccae was first isolated from the Ugandan Lang'o District, where locals claimed that a "muddy substance had the power to cure a number of ailments". Research areas being pursued with regard to killed Mycobacterium vaccae vaccine include immunotherapy for allergic asthma, cancer, depression, leprosy, psoriasis, dermatitis, eczema and tuberculosis.

The Mycobacterium tuberculosis complex is a genetically related group of Mycobacterium species that can cause tuberculosis in humans or other animals.

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<span class="mw-page-title-main">Isochorismate lyase</span>

Isochorismate pyruvate lyase is an enzyme responsible for catalyzing part of the pathway involved in the formation of salicylic acid. More specifically, IPL will use isochorismate as a substrate and convert it into salicylate and pyruvate. IPL is a PchB enzyme originating from the pchB gene in Pseudomonas aeruginosa.

Siderocalin(Scn), lipocalin-2, NGAL, 24p3 is a mammalian lipocalin-type protein that can prevent iron acquisition by pathogenic bacteria by binding siderophores, which are iron-binding chelators made by microorganisms. Iron serves as a key nutrient in host-pathogen interactions, and pathogens can acquire iron from the host organism via synthesis and release siderophores such as enterobactin. Siderocalin is a part of the mammalian defence mechanism and acts as an antibacterial agent. Crystallographic studies of Scn demonstrated that it includes a calyx, a ligand-binding domain that is lined with polar cationic groups. Central to the siderophore/siderocalin recognition mechanism are hybrid electrostatic/cation-pi interactions. To evade the host defences, pathogens evolved to produce structurally varied siderophores that would not be recognized by siderocalin, allowing the bacteria to acquire iron.

Mycolicibacter engbaekii is a species of bacteria from the phylum Actinomycetota. It is susceptible to amikacin, clarithromycin, ethambutol, linezolid, and rifabutin. It has also been recovered from African tuberculosis patients, water treatment plant sludge, and dairy cattle.

References

  1. McMahon, M. D.; Rush, J. S.; Thomas, M. G. (2012). "Analyses of MbtB, MbtE, and MbtF Suggest Revisions to the Mycobactin Biosynthesis Pathway in Mycobacterium tuberculosis". Journal of Bacteriology. 194 (11): 2809–18. doi:10.1128/JB.00088-12. PMC   3370630 . PMID   22447909.
  2. Adúriz, J.J.; Juste, R.A.; Cortabarria, N. (1995). "Lack of mycobactin dependence of mycobacteria isolated on Middlebrook 7H11 from clinical cases of ovine paratuberculosis". Veterinary Microbiology. 45 (2–3): 211–7. doi:10.1016/0378-1135(95)00037-B. PMID   7571372.
  3. Dane, Hannah; Stewart, Linda D; Grant, Irene R (2022-12-13). "Culture ofMycobacterium aviumsubsp.paratuberculosis: challenges, limitations and future prospects". Journal of Applied Microbiology. 134 (1). doi:10.1093/jambio/lxac017. ISSN   1365-2672.