Spirochaetaceae
| Spirochaetaceae | ||||||||||
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Light microscope image of Treponema pallidum |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Spirochaetaceae | ||||||||||
| Swellengrebel 1907 emend. Abt, Göker, Kyrpides & Klenk 2012 |
The spirochetes - Family Spirochaetaceae was first described in 1907 and by the spirilla distinguished, although in light microscopy appear similar image, but are not closely related to the spirochete. The representatives of these gram-negative bacteria are mostly anaerobic , so they can multiply without oxygen. Some species are pathogenic . The infectious diseases caused include syphilis , caused by Treponema pallidum, or Lyme disease , caused by Borrelia burgdorferi . But there are also numerous non-pathogenic species, which can be found, for example, free-living in water.
features
Appearance
The cells are elongated with a helical ( helical ) structure, as is typical for spirochetes . The diameter is in the range of 0.1-3.0 µm with a length of 3.5-250 µm. Representatives of the genera Cristispira and Spirochaeta are particularly large and reach a length of 150 and 250 µm, respectively. The cell ends are not bent like a hook, as is typical for members of the Leptospiraceae family . Under unfavorable conditions, spherical cells are formed. The periplasmic flagella (endoflagella) start at both ends of the cell and extend almost the entire length of the cell, overlapping in the middle of the cell. They give the cells the ability to actively move . The cells behave negatively in the Gram stain .
Growth and metabolism
The representatives of the Spirochaetaceae are chemo - heterotrophic . The metabolism is either strictly anaerobic , i. H. the bacteria show under anaerobic conditions - ie under exclusion of oxygen - growth . Or they are facultative anaerobic species , they grow in the presence or absence of oxygen. The family also includes microaerophilic species; they need oxygen for growth, but in lower concentrations than is found in normal air.
In the metabolism of substances and energy , various carbohydrates are used in one fermentation . Many species also use amino acids as a substrate , this does not apply to the representatives of the genus Spirochaeta . Long-chain fatty acids and fatty alcohols cannot be used. Acetate , lactate , ethanol , molecular hydrogen (H 2 ) and carbon dioxide (CO 2 ) occur as metabolic end products during fermentative degradation . In the case of facultative anerobic species that also undergo oxidative degradation, CO 2 and acetate are usually the end products.
Chemotaxonomy
The GC content , the proportion of the nucleobases guanine and cytosine in the bacterial DNA , lies in a wide range of 36–66 mol percent for the family . The GC content of the type genus Spirochaeta is 50–65 mol percent, for Treponema species 37–54 mol percent. The murein layer in the cell wall contains the diamino acid L - ornithine as a diagnostically important amino acid.
Occurrence
The Spirochaetaceae are either bound to a host or occur free-living. Cristispira is restricted to the digestive tract of certain molluscs . It lives symbiotically in the crystal stem (crystal style) z. B. of oysters . Spirochaeta is found freely living in sea or fresh water. Treponema lives as a commensal or parasite in animals and humans as hosts and occurs in them in the oral cavity , in the intestines and in the area of the genitals . Also Borrelia is bound to hosts and occurs in humans and some other mammals, as well as in ticks , as vectors are used. Clevelandina , Diplocalyx , Hollandina and Pillotina were found in the hindgut of termites or cockroaches , which feed on wood or the cellulose it contains . Also Sphaerochaeta was detected in the hindgut of termites.
Systematics
The Spirochaetaceae family was first described by Swellengrebel in 1907 . He examined aquatic bacteria that were then assigned to the genus Spirochaeta , which was described in 1835 . According to his investigations, they can be distinguished from the spirillae , which appear similar in the light microscopic image, but are not closely related to the spirochetes. The description of the family was expanded in 2012 with the establishment of a new genus, Sphaerochaeta . The bacterial strain that was genetically investigated had previously been assigned to the genus Spirochaeta .
Current system
The family of the Spirochaetaceae is in the order of the Spirochaetales , which includes three more in addition to this family: Brachyspiraceae , Brevinemataceae and Leptospiraceae . The Spirochaetaceae family currently includes nine genera (status 2014), Spirochaeta is the type genus of the family.
- Borrelia Swellengrebel 1907
- Clevelandina Bermudes et al. 1988
- Cristispira Gross 1910
- Diplocalyx (ex Gharagozlou 1968) Bermudes et al. 1988
- Hollandina (ex To et al. 1978) Bermudes et al. 1988
- Pillotina (ex Hollande & Gharagozlou 1967) Bermudes et al. 1988
- Sphaerochaeta Ritalahti 2012 emend. Abt, Göker, Kyrpides & Klenk 2012
- Spirochaeta Ehrenberg emend in 1835. Pikuta et al. 2009
- Treponema ( Schaudinn 1905) Abt, Göker & Klenk 2013
Proposal for a modified system
According to new phylogenetic studies from 2013 by Gupta et al. a. The system of the representatives of the spirochete families has changed. The aim of the investigation was to use molecular markers (so-called signature sequences) to clarify the phylogenetic relationship . To do this, the DNA sequence of certain genes that code for known proteins is determined . Incorporation ( insertion ) or deletion ( deletion ) of short nucleotide sequences in a gene, combined into a class called indel due to the comparable effects , lead to an altered amino acid sequence in the protein. Indels in otherwise little changeable DNA sequences ( conserved areas) are rare genetic changes and suitable as molecular markers if they are common to some species and absent in others.
These markers , known in English as conserved signature indels (“conserved characteristic indels”), were determined and compared among the representatives of the spirochete families. 38 conserved signature indels (CSIs) were found, which are either typical for all representatives of the order of the Spirochaetales or for representatives of the main clades . Seven different CSIs occur only in the Spirochaetaceae, not in the other families. On the other hand, three CSIs were identified that can only be found in Sphaerochaeta , Spirochaeta and Treponema , while 16 CSIs are typical for Borrelia . These results show that the Spirochaetaceae represent a group of very different species, which was already recognized by investigations of the nucleotides of the 16S rRNA, the 16S rRNA is a typical representative of the ribosomal RNA for prokaryotes .
As a result of the investigations, it was suggested that the four families should be raised to the rank of an order because of their clear differences. According to this concept, the order Spirochaetales would no longer include the members of the other three families. It is also proposed to establish a new family of Borreliaceae in addition to the family of Spirochaetaceae, in which the genera Borrelia and Cristispira are placed. Such changes are usually only recognized with the new edition of the important reference work on the phylogenetic systematics of bacteria , Bergey's Manual of Systematic Bacteriology .
Medical importance
Diseases caused by Spirochaetaceae are known as Spirochaetaceae spirochaetoses. The genera Treponema and Borrelia contain important pathogens . Infectious diseases caused by treponema are commonly referred to as treponematoses . Treponema pallidum is the causative agent of syphilis , an infectious disease that belongs to the group of sexually transmitted diseases . An infected person can transmit the bacteria through lesions on the skin or mucous membranes. Treponema pertenue causes framboesia , a skin lesion. Infectious diseases caused by Borrelia are commonly referred to as Borrelioses . The Lyme disease is u. a. caused by Borrelia burgdorferi , other diseases are summarized as relapsing fever and caused, for example, by Borrelia recurrentis and Borrelia duttoni .
swell
literature
- Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria . 3. Edition. tape 7 : Delta and Epsilon Subclasses. Deeply Rooting Bacteria . Springer-Verlag, New York 2006, ISBN 0-387-30747-8 , pp. 195-358 , doi : 10.1007 / 0-387-30747-8 .
- Helmut Hahn, Stefan HE Kaufmann, Thomas F. Schulz, Sebastian Suerbaum (eds.): Medical microbiology and infectiology . 6th edition. Springer Verlag, Heidelberg 2009, ISBN 978-3-540-46359-7 , p. 373-389 .
Individual evidence
- ↑ a b c d e f g h i j Bruce J. Paster u. a .: Family Spirochaetaceae . In: Bergey's Manual of Systematic Bacteriology: Volume 4: The Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres, Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and Planctomycetes . Springer-Verlag, New York 2010, ISBN 978-0-387-95042-6 , pp. 471-501 .
- ↑ a b c d e Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 3-8274-0566-1 , pp. 349, 597-600.
- ↑ a b c d Radhey S. Gupta, Sharmeen Mahmood, Mobolaji Adeolu: 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. In: Frontiers in Microbiology. Volume 4, No. 217, July 29, 2013, ISSN 1664-302X . doi: 10.3389 / fmicb.2013.00217 .
- ↑ D. Bermudes, D. Chase, L. Margulis: Morphology as a basis for taxonomy of large spirochetes symbiotic in wood-eating cockroaches and termites: Pillotina gen. Nov., Nom. rev .; Pillotina calotermitidis sp. nov., nom. rev .; Diplocalyx gen. Nov., Nom. rev .; Diplocalyx calotermitidis sp. nov., nom. rev .; Hollandina gen. Nov., Nom. rev .; Hollandina pterotermitidis sp. nov., nom. rev .; and Clevelandina reticulitermitidis gen. nov., sp. nov. In: International Journal of Systematic Bacteriology. Volume 38, No. 3, July 1988, pp. 291-302, ISSN 0020-7713 . PMID 11542253 .
- ↑ a b Birte Abt, Cliff Han u. a .: Complete genome sequence of the termite hindgut bacterium Spirochaeta coccoides type strain (SPN1T), reclassification in the genus Sphaerochaeta as Sphaerochaeta coccoides comb. nov. and emendations of the family Spirochaetaceae and the genus Sphaerochaeta. In: Standards in Genomic Sciences. Volume 6, No. 2, May 2012, pp. 194-209, ISSN 1944-3277 . doi: 10.4056 / sigs.2796069 .
- ^ Nicolaas Hendrik Swellengrebel: Sur la cytologie comparée des spirochètes et des spirilles. In: Annales de l'Institut Pasteur (Paris). Volume 21, 1907, pp. 562-586, online .
- ^ A b Jean Euzéby, Aidan C. Parte: Family Spirochaetaceae. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved August 2, 2014 .
- ^ Jean Euzéby, Aidan C. Parte: Order Spirochaetales. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved August 2, 2014 .
- ↑ Radhey S. Gupta: The branching order and phylogenetic placement of species from completed bacterial genomes, based on conserved indels found in various proteins. In: International Microbiology. Volume 4, No. 4, December 2001, pp. 187-202. doi: 10.1007 / s10123-001-0037-9 .
- ↑ Gerd B. Roemer: The family of the Spirochaetaceae Spirochätosen. In: Heinz Reploh, Hans Jürgen Otte: Textbook of Medical Microbiology. Edited by Henning Brandis and Hans Jürgen Otte. 5th, revised edition. Stuttgart / New York 1984.
