Spirochaete Explained

A spirochaete [1] or spirochete is a member of the phylum Spirochaetota (also called Spirochaetes[2]), which contains distinctive diderm (double-membrane) Gram-negative bacteria, most of which have long, helically coiled (corkscrew-shaped or spiraled, hence the name) cells.[3] Spirochaetes are chemoheterotrophic in nature, with lengths between 3 and 500 μm and diameters around 0.09 to at least 3 μm.[4]

Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, called endoflagella, or periplasmic flagella, which are sometimes called axial filaments.[5] [6] Endoflagella are anchored at each end (pole) of the bacterium within the periplasmic space (between the inner and outer membranes) where they project backwards to extend the length of the cell.[7] These cause a twisting motion which allows the spirochaete to move. When reproducing, a spirochaete will undergo asexual transverse binary fission. Most spirochaetes are free-living and anaerobic, but there are numerous exceptions. Spirochaete bacteria are diverse in their pathogenic capacity and the ecological niches that they inhabit, as well as molecular characteristics including guanine-cytosine content and genome size.[8] [9]

Pathogenicity

Many organisms within the Spirochaetota phylum cause prevalent diseases. Pathogenic members of this phylum include the following:

Salvarsan, the first partially organic synthetic antimicrobial drug in medical history, was effective against spirochaetes and primarily used to cure syphilis. Additionally, oral spirochaetes are known to play a significant role in the pathogenesis of human periodontal disease.[14]

Taxonomy and molecular signatures

The class currently consists of 14 validly named genera across 4 orders and 5 families.[15] [16] [17] The orders Brachyspirales, Brevinematales and Leptospirales each contain a single family, Brachyspiraceae, Brevinemataceae and Leptospiraceae, respectively. The Spirochaetales order harbours two families, Spirochaetaceae and Borreliaceae. Molecular markers in the form of conserved signature indels (CSIs) and CSPs have been found specific for each of the orders, with the exception of Brevinimetales, that provide a reliable means to demarcate these clades from one another within the diverse phylum.[16] Additional CSIs have been found exclusively shared by each family within the Spirochaetales. These molecular markers are in agreement with the observed phylogenetic tree branching of two monophyletic clades within the Spirochaetales order.[16] CSIs have also been found that further differentiate taxonomic groups within the Borreliaceae family that further delineate evolutionary relationships that are in accordance with physical characteristics such as pathogenicity (viz. Borrelia emend. Borreliella gen. nov.).[18] However, this study has been criticized, and other studies using different approaches do not support the proposed split.[19] The new naming system for the Lyme and relapsing fever Borrelia has not been adopted by the scientific literature.[19]

A CSI has also been found exclusively shared by all Spirochaetota species.[16] This CSI is a 3 amino acid insert in the flagellar basal body rod protein FlgC which is an important part of the unique endoflagellar structure shared by Spirochaetota species.[20] Given that the CSI is exclusively shared by members within this phylum, it has been postulated that it may be related to the characteristic flagellar properties observed among Spirochaetota species.[16] [20]

Historically, all families belonging to the Spirochaetota phylum were assigned to a single order, the Spirochaetales.[8] [9] However, the current taxonomic view is more connotative of accurate evolutionary relationships. The distribution of a CSI is indicative of shared ancestry within the clade for which it is specific. It thus functions as a synapomorphic characteristic, so that the distributions of different CSIs provide the means to identify different orders and families within the phylum and so justify the phylogenetic divisions.[16]

Phylogeny

See also: Bacterial taxonomy.

Taxonomy

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[27] and National Center for Biotechnology Information (NCBI).[28]

See also

External links

Notes and References

  1. Web site: SPIROCHAETE | Meaning & Definition for UK English | Lexico.com. https://web.archive.org/web/20210127083406/https://www.lexico.com/definition/spirochaete . dead . 27 January 2021 . Lexico Dictionaries | English.
  2. Book: Dorland's Illustrated Medical Dictionary . .
  3. Book: Ryan KJ, Ray CG . Sherris Medical Microbiology . 4th . McGraw Hill . 2004 . 978-0-8385-8529-0 .
  4. Margulis L, Ashen JB, Solé M, Guerrero R . Composite, large spirochetes from microbial mats: spirochete structure review . Proceedings of the National Academy of Sciences of the United States of America . 90 . 15 . 6966–6970 . August 1993 . 8346204 . 47056 . 10.1073/pnas.90.15.6966 . 1993PNAS...90.6966M . free . Lynn Margulis .
  5. Nakamura S . Spirochete Flagella and Motility . Biomolecules . 10 . 4 . April 2020 . 550 . 32260454 . 7225975 . 10.3390/biom10040550 . free .
  6. Web site: Carroll KC, Hobden JA, Miller S . Spirochetes and Other Spiral Microorganisms . Jawetz, Melnick, & Adelberg’s Medical Microbiology . McGraw-Hill Education . 9 May 2021 . 2019.
  7. Book: Madigan MT . Brock biology of microorganisms . 2019 . Pearson . NY, NY . 9781292235103 . 519 . Fifteenth, Global.
  8. Book: Paster BJ . 2011 . Phylum XV. Spirochaetes Garrity and Holt. . Bergey's Manual of Systematic Bacteriology . 471 . Brenner DJ, Krieg NR, Garrity GM, Staley JT . Springer . New York .
  9. Book: Paster BJ . 2011 . Family I. Sprochaetes Swellengrebel 1907, 581AL. . Bergey's Manual of Systematic Bacteriology . 473–531 . Brenner DJ, Krieg NR, Garrity GM, Staley JT . Springer . New York.
  10. McBride A, Athanazio D, Reis M, Ko A . Leptospirosis . Current Opinion in Infectious Diseases . 18 . 5 . 376–86 . 2005 . 16148523 . 10.1097/01.qco.0000178824.05715.2c. 220576544 .
  11. Wolcott KA, Margos G, Fingerle V, Becker NS . Host association of Borrelia burgdorferi sensu lato: A review . Ticks and Tick-Borne Diseases . 12 . 5 . 101766 . September 2021 . 34161868 . 10.1016/j.ttbdis.2021.101766 .
  12. Schwan TG . Ticks and Borrelia: model systems for investigating pathogen-arthropod interactions . Infectious Agents and Disease . 5 . 3 . 167–181 . June 1996 . 8805079 .
  13. Amat Villegas I, Borobio Aguilar E, Beloqui Perez R, de Llano Varela P, Oquiñena Legaz S, Martínez-Peñuela Virseda JM . [Colonic spirochetes: an infrequent cause of adult diarrhea] . es. Gastroenterol Hepatol . 27 . 1 . 21–3 . January 2004 . 14718105 . 10.1016/s0210-5705(03)70440-3.
  14. Yousefi L, Leylabadlo HE, Pourlak T, Eslami H, Taghizadeh S, Ganbarov K, Yousefi M, Tanomand A, Yousefi B, Kafil HS . 6 . Oral spirochetes: Pathogenic mechanisms in periodontal disease . Microbial Pathogenesis . 144 . 104193 . July 2020 . 32304795 . 10.1016/j.micpath.2020.104193 . 215818931 .
  15. Web site: Schoch CL, Ciufo S, Domrachev M, Hotton CL, Kannan S, Khovanskaya R, Leipe D, Mcveigh R, O'Neill K, Robbertse B, Sharma S, Soussov V, Sullivan JP, Sun L, Turner S, Karsch-Mizrachi I . 6 . TherSpirochaetia . National Center for Biotechnology Information (NCBI) taxonomy database . 2016-10-25 .
  16. Gupta RS, Mahmood S, Adeolu M . A phylogenomic and molecular signature based approach for characterization of the phylum Spirochaetes and its major clades: proposal for a taxonomic revision of the phylum . Front Microbiol . 4 . 217 . 217 . 2013 . 23908650 . 10.3389/fmicb.2013.00217 . 3726837. free .
  17. Oren A, Garrity GM . List of new names and new combinations previously effectively, but not validly, published . Int. J. Syst. Evol. Microbiol.. 64 . 3 . 693–696. 2014 . 10.1099/ijs.0.062521-0 .
  18. Adeolu M, Gupta RS . A phylogenomic and molecular marker based proposal for the division of the genus Borrelia into two genera: the emended genus Borrelia containing only the members of the relapsing fever Borrelia, and the genus Borreliella gen. nov. containing the members of the Lyme disease Borrelia (Borrelia burgdorferi sensu lato complex). Antonie van Leeuwenhoek . 105 . 6 . 1049–1072. 2014. 24744012. 10.1007/s10482-014-0164-x .
  19. Winslow C, Coburn J . Recent discoveries and advancements in research on the Lyme disease spirochete Borrelia burgdorferi . F1000Research . 8 . 763. 2019 . 31214329 . 6545822 . 10.12688/f1000research.18379.1 . free .
  20. Macnab RM . How bacteria assemble flagella. Annu Rev Microbiol . 57 . 77–100. 2003 . 12730325 . 10.1146/annurev.micro.57.030502.090832.
  21. Web site: The LTP . 20 November 2023.
  22. Web site: LTP_all tree in newick format. 20 November 2023.
  23. Web site: LTP_08_2023 Release Notes. 20 November 2023.
  24. Web site: GTDB release 08-RS214 . Genome Taxonomy Database. 10 May 2023.
  25. Web site: bac120_r214.sp_label . Genome Taxonomy Database. 10 May 2023.
  26. Web site: Taxon History . Genome Taxonomy Database. 10 May 2023.
  27. Web site: Euzéby JP . Spirochaetes . 2018-07-20 . List of Prokaryotic names with Standing in Nomenclature (LPSN).
  28. Web site: Schoch CL, Ciufo S, Domrachev M, Hotton CL, Kannan S, Khovanskaya R, Leipe D, Mcveigh R, O'Neill K, Robbertse B, Sharma S, Soussov V, Sullivan JP, Sun L, Turner S, Karsch-Mizrachi I . 6 . Spirochaetes . 2018-07-20 . National Center for Biotechnology Information (NCBI) taxonomy database .

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