''Micrococcus luteus'' is a

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bac ...

, to Gram-variable, nonmotile,

coccus A coccus (plural cocci) is any bacterium or archaeon that has a spherical, ovoid, or generally round shape. Bacteria are categorized based on their shapes into three classes: cocci (spherical-shaped), bacillus (rod-shaped) and spiral ( of w ...

, tetrad-arranging, pigmented, saprotrophic

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were a ...

that belongs to the family Micrococcaceae. It is urease and

catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting t ...

positive. An obligate aerobe, ''M. luteus'' is found in soil, dust, water and air, and as part of the normal microbiota of the mammalian skin. The bacterium also colonizes the human

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on t ...

, mucosae, oropharynx and upper respiratory tract. ''Micrococcus luteus'' is considered a contaminant in sick patients and is resistant by slowing of major metabolic processes and induction of unique genes. It is a high G + C ratio bacterium. ''Micrococcus luteus'' is

coagulase Coagulase is a protein enzyme produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of '' Staphylococcus'' isolates. Importantly, '' S. aureu ...

negative,

bacitracin Bacitracin is a polypeptide antibiotic. It is a mixture of related cyclic peptides produced by '' Bacillus licheniformis'' bacteria, that was first isolated from the variety "Tracy I" ( ATCC 10716) in 1945. These peptides disrupt Gram-positive ...

susceptible, and forms bright yellow colonies on

nutrient agar Nutrient agar is a general purpose liquid medium supporting growth of a wide range of non-fastidious organisms. It typically contains ( mass/volume): * 0.5% peptone - this provides organic nitrogen * 0.3% beef extract/yeast extract - the wate ...

. ''Micrococcus luteus'' has been shown to survive in oligotrophic environments for extended periods of time. Recent work by Greenblatt ''et al.'' demonstrate that ''Micrococcus luteus'' has survived for at least 34,000 to 170,000 years on the basis of 16S rRNA analysis, and possibly much longer. It was sequenced in 2010 and has one of the smallest genomes of free-living

Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrestrial or aquatic. They are of great economic importance to humans because agriculture and forests depend on their contributions to soi ...

sequenced to date, comprising a single circular

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

of 2,501,097 bp.

Novel codon usage

''Micrococcus luteus'' was one of the early examples of novel

codon The genetic code is the set of rules used by living cells to translate information encoded within genetic material ( DNA or RNA sequences of nucleotide triplets, or codons) into proteins. Translation is accomplished by the ribosome, which links ...

usage, which led to the conclusion that the

genetic code The genetic code is the set of rules used by living cells to translate information encoded within genetic material ( DNA or RNA sequences of nucleotide triplets, or codons) into proteins. Translation is accomplished by the ribosome, which links ...

is not static, but evolves.

Classification

''Micrococcus luteus'' was formerly known as ''Micrococcus lysodeikticus''. In 2003, it was proposed that one strain of ''Micrococcus luteus'', ATCC 9341, be reclassified as ''Kocuria rhizophila''.

Ultraviolet absorption

Norwegian researchers in 2013 found a ''M. luteus'' strain that synthesizes a pigment that absorbs wavelengths of light from 350 to 475 nano-meters. Exposure to these wavelengths of

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

has been correlated with an increased incidence of

skin cancer Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body. There are three main types of skin cancers: basal-cell skin cancer (BC ...

, and scientists believe this pigment can be used to make a sunscreen that can protect against ultraviolet light.

Tests for Identification

References

External links

*
MicrobeWikiType strain of ''Micrococcus luteus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q142000 Micrococcaceae Bacteria described in 1872