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Escherichia coli ( ESH-ə-RIK-ee-ə KOH-ly) is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes such as EPEC, and ETEC are pathogenic and can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains are part of the normal microbiota of the gut and are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of E. coli benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between E. coli and humans are a type of mutualistic biological relationship — where both the humans and the E. coli are benefitting each other. E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh fecal matter under aerobic conditions for three days, but its numbers decline slowly afterwards.
FtsZ is a protein encoded by the ftsZ gene that assembles into a ring at the future site of bacterial cell division. FtsZ is a prokaryotic homologue of the eukaryotic protein tubulin. The initials FtsZ mean "Filamenting temperature-sensitive mutant Z." The hypothesis was that cell division mutants of E. coli would grow as filaments due to the inability of the daughter cells to separate from one another. FtsZ is found in almost all bacteria, many archaea, all chloroplasts and some mitochondria, where it is essential for cell division. FtsZ assembles the cytoskeletal scaffold of the Z ring that, along with additional proteins, constricts to divide the cell in two.
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The bacterial capsule is a large structure common to many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epidemiologic classification of organisms to a level below the species. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.
Filamentation is the anomalous growth of certain bacteria, such as Escherichia coli, in which cells continue to elongate but do not divide. The cells that result from elongation without division have multiple chromosomal copies.
Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.
Swarming motility is a rapid and coordinated translocation of a bacterial population across solid or semi-solid surfaces, and is an example of bacterial multicellularity and swarm behaviour. Swarming motility was first reported by Jorgen Henrichsen and has been mostly studied in genus Serratia, Salmonella, Aeromonas, Bacillus, Yersinia, Pseudomonas, Proteus, Vibrio and Escherichia.
The prokaryotic cytoskeleton is the collective name for all structural filaments in prokaryotes. It was once thought that prokaryotic cells did not possess cytoskeletons, but advances in visualization technology and structure determination led to the discovery of filaments in these cells in the early 1990s. Not only have analogues for all major cytoskeletal proteins in eukaryotes been found in prokaryotes, cytoskeletal proteins with no known eukaryotic homologues have also been discovered. Cytoskeletal elements play essential roles in cell division, protection, shape determination, and polarity determination in various prokaryotes.
Gliding motility is a type of translocation used by microorganisms that is independent of propulsive structures such as flagella, pili, and fimbriae. Gliding allows microorganisms to travel along the surface of low aqueous films. The mechanisms of this motility are only partially known.
Roberto Kolter is Professor of Microbiology, Emeritus at Harvard Medical School, an author, and past president of the American Society for Microbiology. Kolter has been a professor at Harvard Medical School since 1983 and was Co-director of Harvard's Microbial Sciences Initiative from 2003-2018. During the 35-year term of the Kolter laboratory from 1983 to 2018, more than 130 graduate student and postdoctoral trainees explored an eclectic mix of topics gravitating around the study of microbes. Kolter is a fellow of the American Association for the Advancement of Science and of the American Academy of Microbiology.
Bacterial morphological plasticity refers to changes in the shape and size that bacterial cells undergo when they encounter stressful environments. Although bacteria have evolved complex molecular strategies to maintain their shape, many are able to alter their shape as a survival strategy in response to protist predators, antibiotics, the immune response, and other threats.
The divisome is a protein complex in bacteria that is responsible for cell division, constriction of inner and outer membranes during division, and peptidoglycan (PG) synthesis at the division site. The divisome is a membrane protein complex with proteins on both sides of the cytoplasmic membrane. In gram-negative cells it is located in the inner membrane. The divisome is nearly ubiquitous in bacteria although its composition may vary between species.
Bacterial secretion systems are protein complexes present on the cell membranes of bacteria for secretion of substances. Specifically, they are the cellular devices used by pathogenic bacteria to secrete their virulence factors to invade the host cells. They can be classified into different types based on their specific structure, composition and activity. Generally, proteins can be secreted through two different processes. One process is a one-step mechanism in which proteins from the cytoplasm of bacteria are transported and delivered directly through the cell membrane into the host cell. Another involves a two-step activity in which the proteins are first transported out of the inner cell membrane, then deposited in the periplasm, and finally through the outer cell membrane into the host cell.
The Phosphate (Pho) regulon is a regulatory mechanism used for the conservation and management of inorganic phosphate within the cell. It was first discovered in Escherichia coli as an operating system for the bacterial strain, and was later identified in other species. The Pho system is composed of various components including extracellular enzymes and transporters that are capable of phosphate assimilation in addition to extracting inorganic phosphate from organic sources. This is an essential process since phosphate plays an important role in cellular membranes, genetic expression, and metabolism within the cell. Under low nutrient availability, the Pho regulon helps the cell survive and thrive despite a depletion of phosphate within the environment. When this occurs, phosphate starvation-inducible (psi) genes activate other proteins that aid in the transport of inorganic phosphate.
FtsK is a protein in E.Coli involved in bacterial cell division and chromosome segregation. It is one of the largest proteins, consisting of 1329 amino acids. FtsK stands for "Filament temperature sensitive mutant K" because cells expressing a mutant ftsK allele called ftsK44, which encodes an FtsK variant containing an G80A residue change in the second transmembrane segment, fail to divide at high temperatures and form long filaments instead. FtsK, specifically its C-terminal domain, functions as a DNA translocase, interacts with other cell division proteins, and regulates Xer-mediated recombination. FtsK belongs to the AAA superfamily and is present in most bacteria.
A. C. Matin is an Indian-American microbiologist, immunologist, academician and researcher. He is a professor of microbiology and immunology at Stanford University School of Medicine.
Adventurous motility is as a type of gliding motility; unlike most motility mechanisms, adventurous motility does not involve a flagellum. Gliding motility usually involves swarms of bacteria; however, adventurous motility is practiced by individual cells. This gliding is hypothesized to occur via assembly of a type IV secretion system and the extrusion of a polysaccharide slime, or by use of a series of adhesion complexes. The majority of research on adventurous motility has focused on the species, Myxococcus xanthus. The earliest of this research is attributed to Jonathan Hodgkin and Dale Kaiser.
Richard P. Novick is an American microbiologist best known for his work in the fields of plasmid biology, staphylococcal pathobiology and antimicrobial resistance. He is the Recanati Family Professor of Science, Emeritus, at NYU Grossman School of Medicine and is a member of the American National Academy of Sciences. Novick has published over 250 peer-reviewed articles, and several book reviews for the Times Literary Supplement, and is a member of the Editorial Board of the Proceedings of the National Academy of Sciences.
References
- ↑ de Boer, Piet A.J.; Crossley, Robin E.; Rothfield, Lawrence I. (February 1989). "A division inhibitor and a topological specificity factor coded for by the minicell locus determine proper placement of the division septum in E. coli". Cell. 56 (4): 641–649. doi:10.1016/0092-8674(89)90586-2. PMID 2645057. S2CID 7650379.
- 1 2 Adler, H. I.; Fisher, W. D.; Cohen, A.; Hardigree, A. A. (1967-02-01). "MINIATURE escherichia coli CELLS DEFICIENT IN DNA". Proceedings of the National Academy of Sciences. 57 (2): 321–326. Bibcode:1967PNAS...57..321A. doi: 10.1073/pnas.57.2.321 . ISSN 0027-8424. PMC 335508 . PMID 16591472.
- ↑ Frazer, Anne Cornish; Curtiss, Roy (1975), "Production, Properties and Utility of Bacterial Minicells", in Arber, W.; Henle, W.; Hofschneider, P. H.; Humphrey, J. H. (eds.), Current Topics in Microbiology and Immunology, vol. 69, Springer Berlin Heidelberg, pp. 1–84, doi:10.1007/978-3-642-50112-8_1, ISBN 978-3-642-50114-2, PMID 1098854 , retrieved 2020-03-19
- ↑ Treuner-Lange, Anke; Aguiluz, Kryssia; van der Does, Chris; Gómez-Santos, Nuria; Harms, Andrea; Schumacher, Dominik; Lenz, Peter; Hoppert, Michael; Kahnt, Jörg; Muñoz-Dorado, José; Søgaard-Andersen, Lotte (January 2013). "PomZ, a ParA-like protein, regulates Z-ring formation and cell division in Myxococcus xanthus: Regulation of cell division in M. xanthus". Molecular Microbiology. 87 (2): 235–253. doi: 10.1111/mmi.12094 . PMID 23145985. S2CID 206191217.
- ↑ Lee, Jin-Young; Choy, Hyon E.; Lee, Jin-Ho; Kim, Geun-Joong (2015-04-28). "Generation of Minicells from an Endotoxin-Free Gram-Positive Strain Corynebacterium glutamicum". Journal of Microbiology and Biotechnology. 25 (4): 554–558. doi: 10.4014/jmb.1408.08037 . ISSN 1017-7825. PMID 25341464.
- ↑ Reeve, John N.; Mendelson, Neil H.; Coyne, Sheila I.; Hallock, Linda L. (1973-05-01). "Minicells of Bacillus subtilis". Journal of Bacteriology. 114 (2): 860–873. doi:10.1128/jb.114.2.860-873.1973. ISSN 0021-9193. PMC 251848 . PMID 4196259.
- ↑ Ward, John E.; Lutkenhaus, Joe (October 1985). "Overproduction of FtsZ induces minicell formation in E. coli". Cell. 42 (3): 941–949. doi:10.1016/0092-8674(85)90290-9. PMID 2996784. S2CID 36603663.
- ↑ Kawamoto, Akihiro; Morimoto, Yusuke V.; Miyata, Tomoko; Minamino, Tohru; Hughes, Kelly T.; Kato, Takayuki; Namba, Keiichi (December 2013). "Common and distinct structural features of Salmonella injectisome and flagellar basal body". Scientific Reports. 3 (1): 3369. Bibcode:2013NatSR...3E3369K. doi:10.1038/srep03369. ISSN 2045-2322. PMC 3842551 . PMID 24284544.
- 1 2 Rang, Camilla U.; Proenca, Audrey; Buetz, Christen; Shi, Chao; Chao, Lin (2018-09-19). Bowman, Grant R. (ed.). "Minicells as a Damage Disposal Mechanism in Escherichia coli". mSphere. 3 (5): e00428–18, /msphere/3/5/mSphere428–18.atom. doi:10.1128/mSphere.00428-18. ISSN 2379-5042. PMC 6147132 . PMID 30232168.
- ↑ Farley, Madeline M.; Hu, Bo; Margolin, William; Liu, Jun (2016-04-15). de Boer, P. (ed.). "Minicells, Back in Fashion". Journal of Bacteriology. 198 (8): 1186–1195. doi:10.1128/JB.00901-15. ISSN 0021-9193. PMC 4859596 . PMID 26833418.
- ↑ Liu, Jun; Chen, Cheng-Yen; Shiomi, Daisuke; Niki, Hironori; Margolin, William (September 2011). "Visualization of bacteriophage P1 infection by cryo-electron tomography of tiny Escherichia coli". Virology. 417 (2): 304–311. doi:10.1016/j.virol.2011.06.005. PMC 3163801 . PMID 21745674.
- ↑ Briegel, A.; Li, X.; Bilwes, A. M.; Hughes, K. T.; Jensen, G. J.; Crane, B. R. (2012-03-06). "Bacterial chemoreceptor arrays are hexagonally packed trimers of receptor dimers networked by rings of kinase and coupling proteins". Proceedings of the National Academy of Sciences. 109 (10): 3766–3771. Bibcode:2012PNAS..109.3766B. doi: 10.1073/pnas.1115719109 . ISSN 0027-8424. PMC 3309718 . PMID 22355139.
- ↑ "Recombinant Bacterial Minicells (rBMCs)". Vaxiion Therapeutics. Retrieved 2020-03-19.
- ↑ MacDiarmid, Jennifer A.; Mugridge, Nancy B.; Weiss, Jocelyn C.; Phillips, Leo; Burn, Adam L.; Paulin, Richard P.; Haasdyk, Joel E.; Dickson, Kristie-Ann; Brahmbhatt, Vatsala N.; Pattison, Scott T.; James, Alexander C. (May 2007). "Bacterially Derived 400 nm Particles for Encapsulation and Cancer Cell Targeting of Chemotherapeutics". Cancer Cell. 11 (5): 431–445. doi: 10.1016/j.ccr.2007.03.012 . PMID 17482133.
- ↑ Giacalone, Matthew J.; Gentile, Angela M.; Lovitt, Brian T.; Xu, Tong; Surber, Mark W.; Sabbadini, Roger A. (October 2006). "The use of bacterial minicells to transfer plasmid DNA to eukaryotic cells". Cellular Microbiology. 8 (10): 1624–1633. doi:10.1111/j.1462-5822.2006.00737.x. ISSN 1462-5814. PMID 16984417. S2CID 39889761.
- ↑ Carleton, Heather A.; Lara-Tejero, María; Liu, Xiaoyun; Galán, Jorge E. (June 2013). "Engineering the type III secretion system in non-replicating bacterial minicells for antigen delivery". Nature Communications. 4 (1): 1590. Bibcode:2013NatCo...4.1590C. doi:10.1038/ncomms2594. ISSN 2041-1723. PMC 3693737 . PMID 23481398.