Arthrobacter Bussei

''Arthrobacter bussei'' (bus’se.i. N.L. gen. n. ''bussei'', of Busse; named after the German microbiologist Hans-Jürgen Busse) is a pink-coloured, aerobic, coccus-shaped, Gram-stain-positive, oxidase-positive and catalase-positive bacterium isolated from cheese made of cow´s milk. ''A. bussei'' is non-motile and does not form spores. Rod–coccus life cycle is not observed. Cells are 1.1–1.5 µm in diameter. On trypticase soy agar it forms pink-coloured, raised and round colonies, which are 1.0 mm in diameter after 5 days at 30 °C The genome of the strain ''A. bussei'' KR32^T has been fully sequenced.

Characteristics

Morphology

The cells of ''A. bussei'' are coccus-shaped. The bacterium is Gram-stain-positive. The cells have a diameter of 1.1–1.5 μm. A rod-coccus life cycle is not observed. The species is not flagellated and therefore non-motile. Endospores are not formed. On trypticase soy agar the cells forms very small colonies. Their diameter is 1.0 mm after 5 days at 30 °C. Colonies are pink-coloured, opaque and soft. From above colonies appear round in shape and have a smooth edge. From the side the colonies are raised.

Physiology

The metabolism of ''A. bussei'' is based on aerobic respiration. The species is aerobic and needs oxygen to grow. Oxidase test and catalase test are positive. Furthermore, the metabolism can be characterized as chemoorganotrophic and heterotrophic. ''A. bussei'' uses organic compounds as an energy source and synthesize substances. Growth occurs at 1–45 °C and pH 7.0–8.0. Tolerates a maximum of 7.5 % NaCl. Growth on Columbia blood agar but not on violet red bile dextrose agar. The bacterium shows no proteolytic or lipolytic activity. Optimal temperature for growth is 27–30 °C. Trypticase soy agar or trypticase soy broth is suitable for cultivation.

''A. bussei'' is able to hydrolyse aesculin but not gelatine. The bacterium is positive for alkaline phosphatase, esterase (C4), esterase lipase (C8), lipase (C14), leucine arylamidase, valine arylamidase, cystine arylamidase, trypsin, naphthol AS-BI-phosphohydrolase, α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase and α-mannosidase. Negative for α-chymotrypsin, acid phosphatase, β-glucuronidase, N-acetyl-β-glucosaminidase, α-fucosidase, arginine dihydrolase and urease. Within the chemoorgano-heterotrophic metabolism, ''A. bussei'' can use a large number of organic compounds as a source of carbon. These include carbohydrates (pentoses and oligosaccharides), sugar alcohols and amino acids. Under aerobic conditions, for example, D-glucose is used, but no acid is formed, as would be typical for fermentation. Other usable substrates are glycerol, L-arabinose, D-xylose, D-galactose, D-glucose, D-fructose, D-mannose, L-rhamnose, D-mannitol, N-acetylglucosamine, arbutin, aesculin, salicin, D-cellobiose, D-maltose, D-melibiose, sucrose, D-trehalose, D-raffinose, starch, glycogen, D-turanose, potassium gluconate and potassium 5-ketogluconate. Furthermore amino acids leucine and valine are assimilated.

Carbohydrates that cannot be used are erythritol, D-arabinose, D-ribose, L-xylose, D-ribitol, methyl-β-D-xylopyranoside, L-sorbose, dulcitol, inositol, D-sorbitol, Methyl-α-D-mannopyranoside, methyl-α-D-glucopyranoside, amygdalin, D-lactose, inulin, D-melezitose, xylitol, gentiobiose, D-lyxose, D-tagatose, fucose, arabitol and potassium 2-ketogluconate. It cannot reduce nitrate to nitrite.

Chemotaxonomy

The fatty acids occurring in the membrane lipids are iso-C_14:0, iso-C_14:1 cis 9, C_14:0, iso-C_15:1 cis 9, iso-C_15:1 cis 4, iso-C_15:0, anteiso-C_15:0, iso-C_16:1 cis 9, iso-C_16:0, C_16:1 cis 9, C_16:0, C_17:1 cis 10/11, C_17:1 cis 9, iso-C_17:0 and anteiso-C_17:0. The main fatty acids are anteiso-C_15:0 and iso-C_15:0 at 30 °C. At low temperatures (10 °C) monounsaturated fatty acids are produced.

''A. bussei'' produces menaquinone-9 (H₂), which is the main quinone in the genus ''Arthrobacter'', menaquinone-8 (H₂) and menaquinone-9. The bacterium also produces the polar lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and monoacyldimannosyl-monoacylglycerol.

The pink colouration of the bacterium is caused by the C₅₀ carotenoid bacterioruberin and a number of its mono-, di- and tetraglycosylated derivatives.

Phylogeny

''A. bussei'' is assigned in the "pink ''Arthrobacter agilis'' group" within the "''Arthrobacter agilis'' group", which forms a stable clade. The "pink ''Arthrobacter agilis'' group" includes the species ''Arthrobacter agilis'', ''Arthrobacter ruber'' and ''Arthrobacter echini'', which all have a pink pigmentation. Other species of the ''Arthrobacter agilis'' group’, ''Arthrobacter flavus'', ''Arthrobacter tecti'', ''Arthrobacter parietis'' and ''Arthrobacter tumbae'' are yellow or yellow-orange pigmented.

Genome

The genome of strain ''A. bussei'' KR32^T was fully sequenced in 2019 and has a size of 3.63 megabase pairs. There are 3086 proteins annotated. The genome contains, inter alia, genes for the biosynthesis of carotenoids and two putative acyl-CoA desaturases, by which the bacterium can synthesize monounsaturated fatty acids. The genomic DNA G+C content of the type strain is 69.14 mol%, based on the whole genome sequence.

Culture collections

The type strain ''A. bussei'' KR32^T (=DSM 109896^T =LMG 31480^T =NCCB 100733^T ) is available for scientific and commercial purposes.

References

{{Taxonbar, from=Q96372402

Actinomycetota
Bacteria described in 2020
Micrococcaceae