Helicobacteraceae

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Helicobacteracae
Helicobacter pylori

Helicobacter pylori

Systematics
Classification : Creature
Domain : Bacteria (bacteria)
Department : Proteobacteria
Class : Epsilonproteobacteria
Order : Campylobacterales
Family : Helicobacteracae
Scientific name
Helicobacteracae
Garrity et al., 2006

The Helicobacteraceae are a family of bacteria from the proteobacteria division . With the genus Helicobacter , some important pathogens for humans and animals are present. The prefix helix is Greek and means something like spiral and refers to the cell shape of the type genus Helicobacter .

features

The Helicobacteraceae are ecologically and morphologically, in terms of cell shape, very diverse group. There are species with spiral or spindle-shaped as well as curved rod cells, the cells of the thiovulum , however, are round or ovoid. In the species Helicobacter acinonychis , spiral-shaped cells as well as curved rods can occur. U-shapes are also present in the Helicobacter genus . As is typical for proteobacteria, the Gram test is negative.

Some species are microaerophilic , i. that is, they can only survive in low oxygen environments. There are also anaerobic species, they can only live in complete absence of oxygen.

Thiovolum is one of the fastest moving bacteria at 600 micrometers per second.

ecology

Helicobacteraceae is an ecologically very diverse group. Thus Sulfuricurvum kujiense and Sulfurimonas autotrophica sulfur-oxidizing bacteria . They oxidize sulfur compounds such as B. hydrogen sulphide (H 2 S) with oxygen (O 2 ) to elemental sulfur (S). In these reactions is energy free of the bacteria to the assimilation of carbon dioxide is used, so it is chemolithoautotrophically bacteria. Microorganisms that oxidize sulfur are very important for the earth's sulfur cycle .

Sulfuricurvum kujiense can oxidize hydrogen sulfide, elemental sulfur and thiosulfate. It can also use molecular hydrogen (H2) as an electron donor. The bacterium can live in the complete absence of oxygen (anaerobically) and also shows growth under microaerobic conditions with an oxygen concentration of 1%. Under anaerobic conditions, it uses nitrate as the terminal electron acceptor . Nitrite is not used by the bacterium. Under microaerobic conditions, it uses oxygen as an acceptor.

Sulfurimonas autotrophica is strictly aerobic and also uses hydrogen sulfide, elemental sulfur and thiosulfate for sulfur oxidation, but it can only use oxygen as a terminal electron acceptor. It cannot use molecular hydrogen to generate energy either.

Pathogens

Some types of Helicobacter are important pathogens in humans. So Helicobacter pylori is the main cause of gastric and duodenal ulcer and a major risk factor for gastric cancer . The bacterium surrounds itself with ammonia , which it forms from the breakdown of urea by urease . This ammonia coat protects it against stomach acid. The enzyme shows a very high activity in relation to other bacteria. Wolinella is harmless and occurs in the oral cavity of healthy people.

Systematics

The following genera are included in this family:

Individual evidence

  1. ↑ Rüdiger Dörris: Medical Microbiology Thieme Georg Verlag, 2004, ISBN 978-3131297174
  2. ↑ Y. Kodama and K. Watanabe: Sulfuricurvum kujiense gen. Nov., Sp. nov., a facultatively anaerobic, chemolithoautotrophic, sulfur-oxidizing bacterium isolated from an underground crude-oil storage cavity. International Journal of Systematic and Evolutionary Microbiology, 2004, Volume 54, No. 6, pp. 2297-2300.
  3. ↑ F. Inagaki, K. Takai, H. Kobayashi and K. Horikoshi: Sulfurimonas autotrophica gen. Nov., Sp. nov., a novel sulfur-oxidizing ε-proteobacterium isolated from hydrothermal sediments in the Mid-Okinawa Trough. International Journal of Systematic and Evolutionary Microbiology, 2003, Volume 53, No. 6, pp. 1801-1805.
  4. ↑ a b Köhler (Ed.) Medical Microbiology , 8th edition, Munich / Jena 2001, ISBN 978-3-437-41640-8
  5. ↑ 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 .
  6. ↑ 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
  7. ↑ Mileni, M. et al .: Heterologous production in Wolinella succinogenes and characterization of the quinol: fumarate reductase enzymes from Helicobacter pylori and Campylobacter jejuni. In: Biochemical Journal . 2006 Apr 1; ​​395 (1): 191-201.
  8. ↑ JP Euzéby: List of Prokaryotic Names with Standing in Nomenclature - Helicobacteraceae (as of March 14, 2019)

literature

  • Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Microbiology . 11th edition. Pearson Studium, Munich 2006, ISBN 3-8274-0566-1
  • George M. Garrity: Bergey's manual of systematic bacteriology . 2nd Edition. Springer, New York 2005, Vol. 2: The Proteobacteria Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria , ISBN 0-387-24145-0