''Cryptobacterium curtum'' 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 bacte ...

anaerobic Anaerobic means "living, active, occurring, or existing in the absence of free oxygen", as opposed to aerobic which means "living, active, or occurring only in the presence of oxygen." Anaerobic may also refer to: * Anaerobic adhesive, a bonding a ...

rod bacteria isolated from human mouths.

Description

''Cryptobacterium curtum'' are

, obligately anaerobic, non-spore-forming, and rod-shaped bacteria. ''C. curtum'' has been isolated from a

periodontal Periodontology or periodontics (from Ancient Greek , – 'around'; and , – 'tooth', genitive , ) is the specialty of dentistry that studies supporting structures of teeth, as well as diseases and conditions that affect them. The supporting ...

pocket sample of an adult patient and from necrotic

dental pulp The pulp is the connective tissue, nerves, blood vessels, and odontoblasts that comprise the innermost layer of a tooth. The pulp's activity and signalling processes regulate its behaviour. Anatomy The pulp is the neurovascular bundle cent ...

, respectively. ''C. curtum'' can also be isolated from human oral and dental infections like pulpal inflammations, advanced

caries Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...

, dental

abscesses An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...

periodontitis Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main caus ...

. While ''C. curtum'' does not appear to be present in the normal microflora, the nearly double in population size when periodontitis is present. The cells are very short and can occur singly or in masses. These cells are inert in most biochemical tests. They do not hydrolyze starch or

aesculin Aesculin, also called æsculin or esculin, is a coumarin glucoside that naturally occurs in the trees horse chestnut (''Aesculus hippocastanum''), California buckeye (''Aesculus californica''), prickly box (''Bursaria spinosa''), and daphnin (the ...

. They cannot reduce nitrate nor do they grow in the presence or absence of carbohydrates. ''C. curtum'' also had negative results for

indole Indole is an aromatic heterocyclic organic compound with the formula C8 H7 N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environmen ...

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 ...

, and

urease Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous bacteria, fungi, algae, plants, and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-containin ...

tests.

Genome analysis

According to Mavrommatis and colleagues, the

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

of ''C. curtum'' is 1,617,804

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

s long. Of the 1422

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

s predicted, 1364 were protein-coding genes, and were 58

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

s. The majority of the genome (78.5%) is made up of protein-coding genes. A 16S rRNA gene sequence analysis revealed that the two isolates represent a distinct lineage within the family ''

Coriobacteriaceae The Coriobacteriaceae a family of 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 agri ...

'', between the neighboring genera ''

Eggerthella ''Eggerthella'' is a bacterial genus of Actinomycetota, in the family Coriobacteriaceae. Members of this genus are anaerobic, non-sporulating, non-motile, Gram-positive bacilli that grow singly, as pairs, or in short chains. They are found in t ...

'' and ''

Slackia ''Slackia'' is a genus of Actinomycetota, in the family Coriobacteriaceae The Coriobacteriaceae a family of Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrest ...

''. After sequencing, they found that the DNA G+C content is 50–51 molecular %.

Metabolic characteristics

''Cryptobacterium curtum'' is asaccharolytic and unreactive in many of the conventional biochemical tests. Instead, it is able to degrade

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the am ...

and other

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

s found in oral cavities by using the arginine deiminase pathway. This bacterium is able to degrade arginine and produce substantial amounts of

citrulline The organic compound citrulline is an α-amino acid. Its name is derived from ''citrullus'', the Latin word for watermelon. Although named and described by gastroenterologists since the late 19th century, it was first isolated from watermelon in 1 ...

ornithine Ornithine is a non-proteinogenic amino acid that plays a role in the urea cycle. Ornithine is abnormally accumulated in the body in ornithine transcarbamylase deficiency. The radical is ornithyl. Role in urea cycle L-Ornithine is one of the produ ...

and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

. Arginine and citrulline support the growth and reproduction of ''C. curtum''.

References

External links

Type strain of ''Cryptobacterium curtum'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q20686326 Actinomycetota Coriobacteriaceae Bacteria described in 1999