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Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. Around 10% of latent infections progress to active disease which, if left untreated, kill about half of those affected. Typical symptoms of active TB are chronic cough with blood-containing mucus, fever, night sweats, and weight loss. Infection of other organs can cause a wide range of symptoms.
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.
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.
A granuloma is an aggregation of macrophages that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such substances include infectious organisms including bacteria and fungi, as well as other materials such as foreign objects, keratin, and suture fragments.
Mycobacterium leprae is one of the two species of bacteria that cause Hansen's disease (leprosy), a chronic but curable infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, and muscles.
An asymptomatic carrier is a person or other organism that has become infected with a pathogen, but shows no signs or symptoms.
Nontuberculous mycobacteria (NTM), also known as environmental mycobacteria, atypical mycobacteria and mycobacteria other than tuberculosis (MOTT), are mycobacteria which do not cause tuberculosis or leprosy/Hansen's disease. NTM are able to cause pulmonary diseases that resemble tuberculosis. Mycobacteriosis is any of these illnesses, usually meant to exclude tuberculosis. They occur in many animals, including humans and are commonly found in soil and water.
Paratuberculosis is a contagious, chronic and sometimes fatal infection that primarily affects the small intestine of ruminants. It is caused by the bacterium Mycobacterium avium subspecies paratuberculosis. Infections normally affect ruminants, but have also been seen in a variety of nonruminant species, including rabbits, foxes, and birds. Horses, dogs, and nonhuman primates have been infected experimentally. Paratuberculosis is found worldwide, with some states in Australia being the only areas proven to be free of the disease. At least in Canada, the signs of BJD usually start when cattle are four to seven years of age, and then usually only are diagnosed in one animal at a time. Cattle "with signs of Johne’s disease shed billions of bacteria through their manure and serve as a major source of infection for future calves."
Tuberculosis is diagnosed by finding Mycobacterium tuberculosis bacteria in a clinical specimen taken from the patient. While other investigations may strongly suggest tuberculosis as the diagnosis, they cannot confirm it.
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).
Professor John Grange died 10 October 2016 was an English immunologist, epidemiologist, researcher, and academic, and was one of Europe's leading tuberculosis specialists.
Lipoarabinomannan, also called LAM, is a glycolipid, and a virulence factor associated with Mycobacterium tuberculosis, the bacteria responsible for tuberculosis. Its primary function is to inactivate macrophages and scavenge oxidative radicals.
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.
Cord factor, or trehalose dimycolate (TDM), is a glycolipid molecule found in the cell wall of Mycobacterium tuberculosis and similar species. It is the primary lipid found on the exterior of M. tuberculosis cells. Cord factor influences the arrangement of M. tuberculosis cells into long and slender formations, giving its name. Cord factor is virulent towards mammalian cells and critical for survival of M. tuberculosis in hosts, but not outside of hosts. Cord factor has been observed to influence immune responses, induce the formation of granulomas, and inhibit tumor growth. The antimycobacterial drug SQ109 is thought to inhibit TDM production levels and in this way disrupts its cell wall assembly.
Mycothiol is an unusual thiol compound found in the Actinomycetota. It is composed of a cysteine residue with an acetylated amino group linked to glucosamine, which is then linked to inositol. The oxidized, disulfide form of mycothiol (MSSM) is called mycothione, and is reduced to mycothiol by the flavoprotein mycothione reductase. Mycothiol biosynthesis and mycothiol-dependent enzymes such as mycothiol-dependent formaldehyde dehydrogenase and mycothione reductase have been proposed to be good drug targets for the development of treatments for tuberculosis.
Lalita Ramakrishnan is an Indian-born American microbiologist who is known for her contributions to the understanding of the biological mechanism of tuberculosis. As of 2019 she serves as a professor of Immunology and Infectious Diseases at the University of Cambridge, where she is also a Wellcome Trust Principal Research Fellow and a practicing physician. Her research is conducted at the MRC Laboratory of Molecular Biology, where she serves as the Head of the Molecular Immunity Unit of the Department of Medicine embedded at the MRC LMB. Working with Stanley Falkow at Stanford, she developed the strategy of using Mycobacterium marinum infection as a model for tuberculosis. Her work has appeared in a number of journals, including Science, Nature, and Cell. In 2018 and 2019 Ramakrishnan coauthored two influential papers in the British Medical Journal (BMJ) arguing that the widely accepted estimates of the prevalence of latent tuberculosis—estimates used as a basis for allocation of research funds—are far too high. She is married to Mark Troll, a physical chemist.
Dibyendu Sarkar is an Indian biochemist, molecular microbiologist and a Chief Scientist at the Institute of Microbial Technology. He is known for his studies on Mycobacterium tuberculosis (Mtb), the bacterial pathogen causing the disease of tuberculosis. His studies have been documented by way of a number of articles and Google Scholar, an online repository of scientific articles has listed 23 of them. He has also delivered invited speeches which included the Second Annual Meeting on Infectious Diseases held at the Indian Institute of Science in September 2017. He is an elected member of Guha Research Conference and a recipient of the Raman Research Fellowship of the Council of Scientific and Industrial Research. The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards, for his contributions to biosciences, in 2011.
Amit Singh is an Indian microbiologist and an associate professor at the department of microbiology and cell biology of the Indian Institute of Science. A Wellcome-DBT Senior Fellow, Singh is known for his studies on the pathogenesis of Mycobacterium tuberculosis. The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development for 2017/18. He was awarded with the prestigious CSIR- Shanti Swarup Bhatnagar award on 2021 for his phenomenal contributions in bio-scientific research. He received the 2021 Shanti Swarup Bhatnagar Prize for Science and Technology in Biological Science.
James William Moulder was an American microbiologist.
Shabaana A. Khader is an Indian-American microbiologist who is the Bernard and Betty Roizman Professor of Microbiology at the University of Chicago. She is also the Chair of the Department of Microbiology. In an effort to design new vaccines and therapeutic strategies, Khader studies host-pathogen interactions in infectious disease.
References
- ↑ "Yossef Av-Gay | Infectious Diseases". UBC Canada.
- ↑ "ATS: High-dose nitric oxide looks promising for infants with bronchiolitis". MDedge.
- ↑ Shapira, T.; Vimalanathan, S.; Rens, C.; Pichler, V.; Peña-Díaz, S.; Jordana, G.; Rees, W.; Winkler DFH; Sarai, I.; Steiner, T.; Jean, F.; Pelech, S.; Av-Gay, Y. (2022). "Inhibition of glycogen synthase kinase-3-beta (GSK3β) blocks nucleocapsid phosphorylation and SARS-CoV-2 replication". Molecular Biomedicine. 3 (1): 43. doi: 10.1186/s43556-022-00111-1 . PMC 9742639 . PMID 36508083.
- ↑ Av-Gay, Yossef; Hmama, Zakaria; Sun, Jim; Bach, Horacio; Wong, Dennis (29 November 2011). "Mycobacterium tuberculosis protein tyrosine phosphatase (PtpA) excludes host vacuolar-H+–ATPase to inhibit phagosome acidification". Proceedings of the National Academy of Sciences. 108 (48): 19371–19376. Bibcode:2011PNAS..10819371W. doi: 10.1073/pnas.1109201108 . PMC 3228452 . PMID 22087003.
- ↑ Chao, Joseph D.; Wong, Dennis; Av-Gay, Yossef (4 April 2014). "Author profile: Yossef Av-Gay". Journal of Biological Chemistry. 289 (14): 9463–9472. doi: 10.1074/jbc.R113.520015 . PMC 3974996 . PMID 24554699.
