Lactovum miscens

from Wikipedia, the free encyclopedia
Lactovum miscens
Systematics
Department : Firmicutes
Class : Bacilli
Order : Lactic acid bacteria (Lactobacillales)
Family : Streptococcaceae
Genre : Lactovum
Type : Lactovum miscens
Scientific name of the  genus
Lactovum
Matthies et al. 2005
Scientific name of the  species
Lactovum miscens
Matthies et al. 2005

Lactovum miscens is the only species in the genus Lactovum . These are gram-positive bacteria from the order of the Lactobacillales (lactic acid bacteria). They were discovered in an acidic forest floor in Bavaria. A closer examination shows a relationship with the representatives of the genus Lactococcus and Streptococcus . Unlike these bacteria, the cells of Lactovum miscens are egg-shaped.

features

Appearance

The cells of Lactovum miscens resemble cocci , but - as is typical for Oenococcus or Leuconostoc - are ovoid (egg-shaped), with a diameter of 0.7  µm and a length of 1 µm. They are usually arranged in pairs. They do not form endospores and are not actively mobile . The Gram stain is positive.

Growth and metabolism

Lactovum miscens is chemo - heterotrophic and anaerobic . But it is aerotolerant, i. H. grows and reproduces under anaerobic conditions, i.e. without oxygen , and its growth and reproduction are neither promoted nor inhibited by the presence of oxygen. The pH range of growth and reproduction is between pH 3.5 and pH 7.5, the temperature range between 0 and 35 ° C. The bacterium can therefore be described as psychrotolerant , as it is still able to multiply even at relatively low temperatures.

As part of its metabolism of substances and energy , L. miscens can utilize various carbohydrates in one fermentation . Substrates that it can break down are the monosaccharides glucose , fructose and galactose , the disaccharides cellobiose and maltose , the sugar alcohol mannitol and the amino sugars glucosamine and N-acetylglucosamine , the latter being a component of the murein layer in the bacterial cell wall . The end products of fermentation are lactate ( anion of lactic acid ), ethanol , formate (anion of formic acid ) and acetate (anion of acetic acid ). Also, carbon dioxide (CO 2 ) is formed in small amounts, molecular hydrogen (H 2 ) and methane (CH 4 ) are not formed. The variety of fermentation products shows that L. miscens - unlike the related species of the Streptococcaceae family - does not carry out homofermentative lactic acid fermentation .

Further examinations of the metabolism showed that L. miscens breaks down the sugars via the metabolic pathway of glycolysis , here pyruvate (anion of pyruvic acid ) is the end product. Part of the pyruvate is reduced to lactate with the help of the enzyme lactate dehydrogenase , and pyruvate is converted to formate and acetyl-CoA , which can be hydrolyzed to acetate , by the enzyme pyruvate formate lyase . Bacteria that undergo heterofermentative lactic acid fermentation usually lack the enzyme aldolase , which catalyzes a glycolysis step. In this respect, L. miscens seems to belong to the homofermentative species. Because of the large number of fermentation products, the fermentation carried out is called mixed fermentation ( English mixed-fermentative metabolism ).

Chemotaxonomy

As a representative of the Firmicutes , Lactovum miscens is one of the bacteria with a low GC content , i.e. a low proportion of the nucleobases guanine and cytosine in the bacterial DNA . The GC content is 37.6  mol percent . The value is within the GC contents of the related genera (34 to 46 mol percent). The genome has not yet been fully sequenced (as of 2014) . However, the nucleotides of the 16S rRNA, a typical representative of ribosomal RNA for prokaryotes , were determined for phylogenetic studies .

Pathogenicity

Lactovum miscens is not pathogenic ("pathogenic") and is assigned to risk group 1 by the Biological Agents Ordinance in conjunction with the TRBA ( Technical Rules for Biological Agents) 466 .

Occurrence

Lactovum miscens was isolated from a soil sample . It is an acid forest soil in Bavaria , the pH value of an aqueous suspension of the soil was pH 4.5 at the time of sampling.

Systematics

Lactovum miscens is the only species and thus also the type species of the genus Lactovum and belongs to the Streptococcaceae family in the order of the Lactobacillales (lactic acid bacteria). This order is part of the department of Firmicutes. L. miscens was isolated, examined and first described in 2004 by Carola Matthies and other scientists from the University of Bayreuth . With publication in Validation List No. 102 in 2005, the species and genus were recognized according to the rules of the bacteriological code .

The bacterial strain anNAG3 discovered in the forest floor is the type strain of the species. It was deposited in the collections of microorganisms in the USA (as ATCC BAA-490) and Germany (at the DSMZ as DSM 14925). The phylogenetic examination revealed a relationship to the genera Lactococcus and Streptococcus , which until 2004 were the only members of the Streptococcaceae family. The comparison of the sequences of the 16S rRNA showed a similarity of 88 and 89%, respectively. The differences were sufficient to establish a type species of a new genus. This is supported by phenotypic characteristics, for example the special fermentation.

etymology

The generic name Lactovum is derived from the Latin words lac , lactis ("milk") and ovum ("egg"), so that a literal translation is "milk egg" or "egg from milk". The name was chosen based on Lactococcus , a related genus, whereby the cells of Lactovum in comparison are not spherical (cokkoid), but rather egg-shaped (ovoid). The species name is derived from the Latin verb miscere ("to mix") and refers to the mixed fermentation that L. miscens carries out.

Individual evidence

  1. ↑ a b c d e f g h i C. Matthies, A. Gössner u. a .: Lactovum miscens gen. nov., sp. nov., an aerotolerant, psychrotolerant, mixed-fermentative anaerobe from acidic forest soil. In: Research in Microbiology. Volume 155, No. 10, December 2004, pp. 847-854, ISSN  0923-2508 . doi : 10.1016 / j.resmic.2004.06.006 . PMID 15567280 .
  2. ↑ a b c Michael T. Madigan, John M. Martinko, Jack Parker: Brock Mikrobiologie. German translation edited by Werner Goebel, 1st edition. Spectrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 978-3-8274-0566-1 , pp. 558-563, 693.
  3. ↑ a b Lactovum miscens strain anNAG3 16S ribosomal RNA gene, complete sequence. In: Nucleotide website of Lactovum miscens of the National Center for Biotechnology Information (NCBI) . Retrieved July 30, 2014 .
  4. ↑ TRBA (Technical Rules for Biological Agents) 466: Classification of prokaryotes (Bacteria and Archaea) into risk groups. In: Website of the Federal Institute for Occupational Safety and Health (BAuA). April 25, 2012, p. 116 , accessed April 30, 2014 .
  5. ↑ a b Jean Euzéby, Aidan C. Part: Genus Lactovum. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved July 30, 2014 .
  6. ↑ unknown: Validation of publication of new names and new combinations previously effectively published outside the IJSEM - Validation List no.102 . In: International Journal of Systematic and Evolutionary Microbiology . tape 55 , no. 2 , March 1, 2005, ISSN  1466-5026 , p. 547-549 , doi : 10.1099 / ijs.0.63680-0 .
  7. ↑ Taxonomy Browser Lactovum miscens. In: National Center for Biotechnology Information (NCBI) website . Retrieved July 31, 2014 .