''Streptococcus sobrinus'' is a Gram-positive, catalase-negative, non-motile, and anaerobic member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

'' Streptococcus''.

Pathology

''Streptococcus sobrinus'' in conjunction with the closely related

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

Streptococcus mutans ''Streptococcus mutans'' is a facultatively anaerobic, gram-positive coccus (round bacterium) commonly found in the human oral cavity and is a significant contributor to tooth decay. It is part of the " streptococci" (plural, non-italic lowercase ...

'' are

pathogenic In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

within humans and enhances the formation of

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 ...

within

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

Biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

from the mixture of sugar and plaque create a suitable environment for ''S. sobrinus'' to grow. ''S. sobrinus'' is more closely connected with the prevalence of caries than ''S. mutans''. ''S. sobrinus'' is also affiliated with early childhood caries, which are responsible for the majority of dental abscesses and

toothaches Toothache, also known as dental pain,Segen JC. (2002). ''McGraw-Hill Concise Dictionary of Modern Medicine''. The McGraw-Hill Companies. is pain in the teeth or their supporting structures, caused by dental diseases or pain referred to the te ...

in children. Children generally acquire ''S. sobrinus'' strains from their mother, but the relatively high consumption of sugars by minors facilitates bacterial growth and threatens the onset of early childhood tooth decay. ''S. sobrinus'' has also been documented within the teeth of

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

History

''Streptococcus sobrinus'' was discovered by the French biologist

Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...

in 1887 along with other human pathogens. The full

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 ''S. sobrinus'' has been sequenced, and the related species ''S. mutans'' has also been fully sequenced.

Symbiosis

Extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

long-chained

glucans A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Glucans are noted in two forms: alpha glucans and beta glucans. Many beta-glucans are medically important. They represent a drug target for antifungal medications of ...

synthesized from

sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...

via

glucosyltransferase Glucosyltransferases are a type of glycosyltransferase that enable the transfer of glucose. Examples include: * glycogen synthase * glycogen phosphorylase Glycogen phosphorylase is one of the phosphorylase enzymes (). Glycogen phosphorylase cat ...

enzymes Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

help accumulate ''S. sobrinus'' on

tooth enamel Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The ...

surfaces. The glucans provide a shelter for bacterial colonization, and the protected environment creates the perfect nesting ground for ''S. sobrinus'' and other microorganisms to sustain a stable community in the form of dental plaque. ''S. sobrinus'' in turn releases

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...

in the anaerobic metabolism of

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

. Lactic acid demineralizes tooth enamel and fosters the initiation of dental caries. ''S. sobrinus'' has an optimal growth

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

of 37 °C and thrives in a slightly acidic environment at a pH of 6.3. This makes 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 ...

a suitable

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

due to its acidic characteristics, favorable body temperature, and significant amount of food sugars passing through the mouth on a daily basis. However, these traits also indicate that ''S. sobrinus'' has a difficult time surviving outside the host of the human teeth.

Antibacterials

In 1995 a paper by Meurman et al. tested '' Lactobacillus'' rhamnosus for inhibitory properties, although this relationship was only observed with a weak correlation at a pH below 5.

Lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in rec ...

from '' Talisia esculenta'' and Labramin from ''

Labramia bojeri ''Labramia'' is a genus of plants in the family Sapotaceae described as a genus in 1844. De Candolle initially named the genus ''Delastrea'', which is a homonym for an older fungus name by Tulasne, so De Candolle changed the name to ''Labramia'' ...

'' seeds were found to inhibit the adherence of ''S. sobrinus'' to tooth enamel, but had no effect on the growth of the population itself. A study by Sun et al. in 2009, tested a vaccine for ''S. sobrinus'', and initial tests have been successful in providing protection.

References

External links