Helicobacter
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| Goodwin et al. 1989 emend. Vandamme et al. 1991 |
Helicobacter is a genus of bacteria fromthe Helicobacteraceae family . Many species are pathogenic (pathogenic).
features
The cells can be spiral, curved, or spindle-shaped with a diameter of 0.2-1.2 X 1.5-10.0 micrometers. Cocci can also occur in older cultures . In some species, periplasmic, tightly twisted fibers appear on the cell surface. Some species also have a glycocalyx . The flagella are cluster-shaped and either monopolar (at one cell end) or bipolar (at both cell ends). The species Helicobacter mustelae is flagellated peritrich, the flagella are distributed over the whole cell body. It triggers gastritis in ferrets . H. mustelae is an important test object for studying gastritis caused by Heliocobacter species .
In some species, the flagella are surrounded by a membrane-like covering. These types include B. Helicobacter pylori , H. bilis and H. canis . During an investigation of the flagella of H. pylori in 1990 it was found that the filament of the flagella not only consists of a single flagellin protein (homopolymer), as is the case with most bacterial species, but is formed from two different proteins, namely FlaA and FlaB. The protein FlaA dominates in terms of quantity, while the FlaB formed in smaller quantities is exclusively located in the area near the hook of the flagella.
The types of Helicobacter are microaerophilic bacteria, they require environments with low oxygen levels. All species show growth at 3 - 7% oxygen, at higher concentrations no growth takes place. Some strains of different species also show weak growth in the complete absence of oxygen, i.e. under anaerobic conditions.
Pigments are not formed. However, some species show a blue-gray coloration when cultured with blood agar.
The oxidase test is positive for all species. Many species have the enzyme urease to break down urea ; the species Helicobacter pylori produces this enzyme in large quantities to protect against the gastric acid of the host. Also, alkaline phosphatase , an enzyme for hydrolysis of organophosphate is formed by many.
The genus belongs to the Epsilonproteobacteria , the Gram test is negative, as is typical for the proteobacteria. The genome of the species Helicobacter pylori has been completely sequenced .
Pathogens
Helicobacter is divided into gastric ( e.g. Helicobacter pylori ) and enterohepatic ( e.g. H. hepaticus and H. bilis ) species .
Helicobacter pylori is the main cause of gastric and duodenal ulcers and a major risk factor for gastric cancer . The bacterium surrounds itself with ammonia , which results from the breakdown of urea by the enzyme urease . This ammonia coat protects it against stomach acid. The enzyme shows a very high activity in relation to other bacteria. The Helicobacter urease test serves as proof .
Systematics
A selection of the types of Helicobacter :
- Helicobacter acinonychis corrig. Eaton et al. 1993
- Helicobacter anseris Fox et al. 2006
- Helicobacter aurati Patterson et al. 2002
- Helicobacter bilis Fox et al. 1997
- Helicobacter bizzozeronii Hänninen et al. 1996
- Helicobacter canis Stanley et al. 1994
- Helicobacter cetorum Harper et al. 2006
- Helicobacter cynogastricus Van den Bulck et al. 2006
- Helicobacter felis Paster et al. 1991
- Helicobacter Heilmannii Smet et al. 2012
- Helicobacter hepaticus Fox et al. 1994
- Helicobacter muridarum Lee et al. 1992
- Helicobacter mustelae (Fox et al. 1988) Goodwin et al. 1989
- Helicobacter pullorum Stanley et al. 1995
- Helicobacter pylori (Marshall et al. 1985) Goodwin et al. 1989
- Helicobacter salomonis Jalava et al. 1997
- Helicobacter suis Baele et al. 2008
- Helicobacter trogontum Mendes et al. 1996
Individual evidence
- ↑ a b c d e f George M. Garrity, Don J. Brenner, Noel R. Krieg, James T. Staley (Eds.): Bergey's manual of systematic bacteriology. Vol. 2: The Proteobacteria Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria. 2nd Edition. Springer, New York 2005, ISBN 978-0-387-24145-6
- ↑ a b c Wolfgang F. Caspary, Manfred Kist and Martin Zeitz: Ecosystem Gut VI: Immunology, Microbiology Functional Disorders, Clinical Manifestation Springer-Verlag 2013, ISBN 9783642851872
- ↑ Magdalena Kostrzynska et al .: Identification, characterization, and spatial localization of two flagellin species in Helicobacter pylori flagella. In: Journal of Bacteriology , February 1991, pp. 937-946. doi : 10.1128 / jb.173.3.937-946.1991
- ↑ a b Werner Köhler (Ed.) Medical Microbiology , 8th edition, Munich / Jena 2001 ISBN 978-3-437-41640-8
- ↑ Georg Fuchs (Ed.): General Microbiology (started by Hans G. Schlegel). 8th edition. Georg Thieme Verlag, Stuttgart, New York 2007, ISBN 978-3-13-444608-1 .
- ↑ Klaus Dörner, Renate Dörner, Th. Deufel: Clinical chemistry and hematology. Thieme Georg Verlag, 2009, ISBN 9783131253132
- ↑ Euzéby: List of Prokaryotic names with Standing in Nomenclature - Helicobacter (as of March 14, 2019)
literature
- George M. Garrity, Don J. Brenner, Noel R. Krieg, James T. Staley (Eds.): Bergey's manual of systematic bacteriology. Vol. 2: The Proteobacteria Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria. 2nd Edition. Springer, New York 2005, ISBN 978-0-387-24145-6
Web links
Helicobacter pylori infection German Nutrition Society