Sporosarcina ureae

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Sporosarcina ureae
Systematics
Department : Firmicutes
Class : Bacilli
Order : Bacillales
Family : Planococcaceae
Genre : Sporosarcina
Type : Sporosarcina ureae
Scientific name
Sporosarcina ureae
( Beijerinck 1901) Kluyver and van Niel 1936

Sporosarcina ureae is a type of bacteria . It is the type species of its genus and is related to Bacillus species. Like this, it occurs in the ground . It is also able tobreak down urea , this peculiarity is recorded in the species name ( Latin urea , "urea"). The generic name is derived from the Greek word spora ("spore") and the Latin word sarcina ("package", "bundle") and refers to the fact that itforms endospores and the typical arrangement of the cells .

features

Appearance

The cells of Sporosarcina ureae are gram-positive and cocci-shaped . The cell division takes place in two or three successive planes, as nibbles or parcels also by eight or more cells are formed. The diameter of the cells is between 1.0 and 2.5  μm . S. ureae is motile by some randomly positioned flagella , it can move itself. Like all species of the genus, S. ureae forms endospores as a persistent form. The diameter of the endospores is between 0.5 and 1.5 μm. The endospores are spherical and are formed centrally or laterally in the mother cell. In the light microscope image they can be seen as bright, refractive shapes.

The cells grow into gray colonies on solid culture media . These are opaque , round when viewed from above and with a clear border, slightly convex when viewed from the side. Yellowish, brownish or orange pigments are formed on some culture media .

Growth and metabolism

The species Sporosarcina ureae is heterotrophic , it does not perform photosynthesis . Metabolism is based on breathing . The species is strictly aerobic , i. H. relies on oxygen , growth in the absence of oxygen does not take place. The catalase and oxidase tests are positive. The pH value for best growth is 7. The species is alkali-tolerant and also grows at pH values ​​of 9 to 10. It is mesophilic , the optimal temperature for growth is 25 ° C. Weak growth can still occur at 37 ° C, but no more at higher temperatures. S. ureae can be cultivated in a nutrient medium that, in addition to peptone and yeast extract, also contains urea or ammonium chloride .

The spore formation does not take place automatically, but is triggered by certain environmental influences on the cells. The formation of endospores occurs, for example, when the temperature for the incubation is below 22 ° C. The endospores are heat resistant , they survive heating to 80 ° C for 10 minutes and after that can germinate. As is common with bacterial endospores, they contain dipicolinic acid .

As noted in the epithet , S. ureae can break down urea ( Latin urea ) with the help of the enzyme urease . The urea (NH 2 -CO-NH 2 ) is "split" (hydrolyzed ) by reacting with water (H 2 O). Depending on the pH of the solution, ammonia (NH 3 ) or ammonium ions ( NH 4 + ) and carbon dioxide (CO 2 ) or carbonate or hydrogen carbonate ions:

or.

Ammonium assimilation in Sporosarcina ureae , compounds involved
2-oxopentanedioic acid 200.svg
Structural formula of α-ketoglutaric acid (2-oxoglutaric acid ), the anion is referred to as α-ketoglutarate or 2-oxoglutarate.
L-Glutamic acid - L-Glutamic acid.svg
Structural formula of L - glutamic acid , the anion is called glutamate.
L-Glutamine - L-Glutamine.svg
Structural formula of L - glutamine

S. ureae can also use ammonium ions directly from the nutrient medium, if this z. B. ammonium chloride (NH 4 Cl) contains. In the metabolism ammonium is assimilated to derive glutamic acid and glutamine , two amino acids to manufacture. Biochemical and metabolic physiological studies show that S. ureae carries out a metabolic pathway similar to the GS-GOGAT pathway, named after the enzymes involved, glutamine synthetase and glutamine oxoglutarate aminotransferase . However, no activity of glutamine synthetase (current name: glutamate ammonium ligase) is recognizable, but GOGAT activity, as a result of which the amino acid glutamine becomes an amino group on 2-oxoglutarate ( α-ketoglutarate , the anion of 2-oxoglutaric acid ), whereby glutamate (the anion of glutamic acid) is formed. The reverse reaction is catalyzed in the same way:

2 glutamate → glutamine + 2-oxoglutarate + e -
Simplified reaction equation, the enzyme involved is glutamine oxoglutarate aminotransferase, the electrons (e - ) are transferred to the electron acceptor NAD + (oxidized form of nicotinamide adenine dinucleotide ).

In addition, glutamate dehydrogenase (GDH) can be detected, this enzyme catalyzes the conversion of glutamate into 2-oxoglutarate and ammonium. Since the GDH also catalyzes the reverse reaction, this enzyme is primarily involved in the assimilation of ammonium:

2-oxoglutarate + NH 4 + + e - → glutamate + H 2 O
Simplified reaction equation, the enzyme involved is glutamate dehydrogenase, the electrons (e - ) are transferred by the electron donor NADH (reduced form of nicotinamide adenine dinucleotide).

genetics

The genome of the strain Sporosarcina ureae DSM 2281 was completely sequenced in 2013 , this is the type strain of the species. The genome has a size of 3319 kilobase pairs (kb), which is about 70% of the genome size of Escherichia coli . The genome was researched as part of the KMG project, in which 1000 genomes of microorganisms ( one thousand microbial genomes ) are sequenced in order to create a “ Genomic Encyclopedia of Type Strains” . In this way, the relationships between the microorganisms should be clarified through phylogenetic studies. The result of the sequencing shows a low GC content (the proportion of the nucleobases guanine and cytosine ) in the bacterial DNA , at around 41 mol percent. A low GC content is typical of the representatives of the order Bacillales and other Firmicutes.

Pathogenicity

Sporosarcina ureae is not pathogenic ("pathogenic"), it is assigned to risk group 1 by the Biological Agents Ordinance in conjunction with the TRBA ( Technical Rules for Biological Agents) 466 .

proof

Biochemical features, such as the enzymes present, can be used in a “colored row” to identify Sporosarcina ureae . In addition to the positive catalase and oxidase test, the following characteristics can be used to distinguish it from the other types: It can reduce nitrate to nitrite , but this denitrification does not produce any gas (molecular nitrogen ). It has the enzyme urease. It cannot use starch , gelatin or casein through hydrolysis . The Voges-Proskauer reaction and the indole test are negative.

The cell wall of S. ureae consists of the peptidoglycan typical of gram-positive bacteria . In the peptides it contains , the combination of the amino acids lysine , glycine and D- glutamic acid is typical and enables it to be differentiated from other types of Sporosarcina . The lipids in the cell membrane contain phosphatidylethanolamines . The main menaquinones are of the MK-7 type.

A selective medium for isolation is not available, but the urease activity of S. ureae can be used. If the nutrient medium has a relatively high content of urea (3–5%), it can grow on it and utilize the urea. Most urease-positive bacteria are inhibited in their growth by a high urea content. a. towards Bacillus mycoides , which is often present in soil samples along with S. ureae .

Occurrence and ecology

Sporosarcina ureae is one of the bacteria that can utilize urea, it has the enzyme urease. It often occurs in the ground . It forms the highest population densities in soils that are subject to the influence of urine . These include B. Pastures , as well as the soil of trees on which dogs urinate. Since urea is the end product of the metabolism of nitrogen compounds in many living things, it is a typical component of urine. S. ureae therefore plays an important role in the breakdown of urine in the environment. It is also found in manure .

Systematics

It was first described in 1901 by Martinus Willem Beijerinck , who named the bacterium as Planosarcina ureae . Because of the typical arrangement of the cells, which are known as sarcines, the bacterium was assigned to the genus Sarcina as Sarcina ureae in 1911 . Only through the description of an independent genus Sporosarcina (1936) was the currently still valid assignment to the genus. In the 1970s, it was recognized that S. ureae is related to Bacillus species, particularly Bacillus pasteurii . Like these, it is gram-positive, grows strictly aerobically, is motile by flagella and forms endospores. There is one difference in the shape of the cells ; Bacillus species are rod-shaped bacteria. The relationship was confirmed by genetic studies in 1992, in which the 16S rRNA, a representative of ribosomal RNA typical of prokaryotes, was examined. In the systematics of the bacteria this was taken into account by assignment to the common order Bacillales in the department of Firmicutes . The species Sporosarcina ureae belongs to the Planococcaceae family .

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literature

  • Paul Vos, George Garrity, Dorothy Jones, Noel R. Krieg, Wolfgang Ludwig, Fred A. Rainey, Karl-Heinz Schleifer, William B. Whitman: Bergey's Manual of Systematic Bacteriology: Volume 3: The Firmicutes . Springer, 2009, ISBN 978-0-387-95041-9 .
  • Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria, Volume 4: Bacteria: Firmicutes, Cyanobacteria . 3. Edition. Springer-Verlag, New York 2006, ISBN 0-387-25494-3 .

Individual evidence

  1. ↑ a b c d e Michael T. Madigan, John M. Martinko: Brock microbiology . 11th edition. Addison-Wesley Verlag, Munich 2006, ISBN 3-8273-7187-2 .
  2. ^ A b Paul Vos, George Garrity, Dorothy Jones, Noel R. Krieg, Wolfgang Ludwig, Fred A. Rainey, Karl-Heinz Schleifer, William B. Whitman: Bergey's Manual of Systematic Bacteriology: Volume 3: The Firmicutes . Springer, 2009, ISBN 978-0-387-95041-9 .
  3. ↑ a b c d e f g h i j k Dieter Claus, Dagmar Fritze, Miloslav Kocur: Genera Related to the Genus Bacillus - Sporolactobacillus, Sporosarcina, Planococcus, Filibacter and Caryophanon (Chapter 1.2.19) . In: Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (eds.): The Prokaryotes. A Handbook on the Biology of Bacteria, Volume 4: Bacteria: Firmicutes, Cyanobacteria . 3. Edition. Springer-Verlag, New York 2006, ISBN 0-387-25494-3 , pp. 631-641 , doi : 10.1007 / 0-387-30744-3_19 .
  4. ↑ a b Georg Fuchs Thomas Eitinger, Erwin Schneider; Founded by Hans. G. Schlegel (Ed.): General Microbiology . Thieme, 2007, ISBN 978-3-13-444608-1 .
  5. ↑ a b G. Mörsdorf, H. Kaltwasser: Ammonium assimilation in Proteus vulgaris, Bacillus pasteurii, and Sporosarcina ureae. In: Archives of microbiology. Volume 152, Number 2, 1989, pp. 125-131, ISSN  0302-8933 . PMID 2570557 .
  6. ↑ a b c Sporosarcina ureae DSM 2281. In: Website Genomes Online Database (GOLD) . Retrieved January 11, 2014 .
  7. ^ A b c Jean Euzéby, Aidan C. Parte: Genus Sporosarcina. In: List of Prokaryotic names with Standing in Nomenclature ( LPSN ). Retrieved December 30, 2013 .
  8. ↑ Sporosarcina ureae DSM 2281. In: Website Bioproject of the National Center for Biotechnology Information (NCBI) . Retrieved January 11, 2014 .
  9. ↑ 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. 208 , accessed January 7, 2014 .
  10. ↑ Taxonomy Browser Sporosarcina ureae. In: National Center for Biotechnology Information (NCBI) website . Retrieved January 11, 2014 .
  11. ^ JA Farrow, C. Ash, S. Wallbanks, MD Collins: Phylogenetic analysis of the genera Planococcus, Marinococcus and Sporosarcina and their relationships to members of the genus Bacillus. In: FEMS microbiology letters. Volume 72, Number 2, June 1992, pp. 167-172, ISSN  0378-1097 . PMID 1505740 .