Streptococcus is a genus of gram-positive or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales, in the phylum Bacillota. Cell division in streptococci occurs along a single axis, thus when growing they tend to form pairs or chains, which may appear bent or twisted. This differs from staphylococci, which divide along multiple axes, thereby generating irregular, grape-like clusters of cells. Most streptococci are oxidase-negative and catalase-negative, and many are facultative anaerobes.
The Thermoproteota are prokaryotes that have been classified as a phylum of the domain Archaea. Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteristic Thermoproteota environmental rRNA indicating the organisms may be the most abundant archaea in the marine environment. Originally, they were separated from the other archaea based on rRNA sequences; other physiological features, such as lack of histones, have supported this division, although some crenarchaea were found to have histones. Until 2005 all cultured Thermoproteota had been thermophilic or hyperthermophilic organisms, some of which have the ability to grow at up to 113 °C. These organisms stain Gram negative and are morphologically diverse, having rod, cocci, filamentous and oddly-shaped cells. Recent evidence shows that some members of the Thermoproteota are methanogens.
Lactococcus lactis is a gram-positive bacterium used extensively in the production of buttermilk and cheese, but has also become famous as the first genetically modified organism to be used alive for the treatment of human disease. L. lactis cells are cocci that group in pairs and short chains, and, depending on growth conditions, appear ovoid with a typical length of 0.5 - 1.5 μm. L. lactis does not produce spores (nonsporulating) and are not motile (nonmotile). They have a homofermentative metabolism, meaning they produce lactic acid from sugars. They've also been reported to produce exclusive L-(+)-lactic acid. However, reported D-(−)-lactic acid can be produced when cultured at low pH. The capability to produce lactic acid is one of the reasons why L. lactis is one of the most important microorganisms in the dairy industry. Based on its history in food fermentation, L. lactis has generally recognized as safe (GRAS) status, with few case reports of it being an opportunistic pathogen.
In molecular biology, a hybridization probe (HP) is a fragment of DNA or RNA, usually 15–10000 nucleotides long, which can be radioactively or fluorescently labeled. HPs can be used to detect the presence of nucleotide sequences in analyzed RNA or DNA that are complementary to the sequence in the probe. The labeled probe is first denatured into single stranded DNA (ssDNA) and then hybridized to the target ssDNA or RNA immobilized on a membrane or in situ.
Streptococcus salivarius is a species of spherical, gram-positive, facultative anaerobic lactic acid bacteria that is both catalase and oxidase negative. S. salivarius colonizes the oral cavity and upper respiratory tract of humans just a few hours after birth, making further exposure to the bacteria harmless in most circumstances. The bacterium is considered an opportunistic pathogen, rarely finding its way into the bloodstream, where it has been implicated in cases of sepsis in people with neutropenia,.
Streptococcus sanguinis, formerly known as Streptococcus sanguis, is a Gram-positive facultative anaerobic coccus species of bacteria and a member of the Viridans Streptococcus group. S. sanguinis is a normal inhabitant of the healthy human mouth where it is particularly found in dental plaque, where it modifies the environment to make it less hospitable for other strains of Streptococcus that cause cavities, such as Streptococcus mutans.
The rpoB gene encodes the β subunit of bacterial RNA polymerase and the homologous plastid-encoded RNA polymerase (PEP). It codes for 1342 amino acids in E. coli, making it the second-largest polypeptide in the bacterial cell. It is targeted by the rifamycin family of antibacterials, such as rifampin. Mutations in rpoB that confer resistance to rifamycins do so by altering the protein's drug-binding residues, thereby reducing affinity for these antibiotics.
The Lactobacillaceae are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the Lactobacillaceae, the pathway used for hexose fermentation is a genus-specific trait. Lactobacillaceae include the homofermentative lactobacilli Lactobacillus, Holzapfelia, Amylolactobacillus, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Loigolactobacillus, Lacticaseibacillus, Latilactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus, and Lactiplantibacillus; the heterofermentative lactobacilli Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Levilactobacillus, Secundilactobacillus, and Lentilactobacillus, which were previously classified in the genus Lactobacillus; and the heterofermentative genera Convivina, Fructobacillus, Leuconostoc, Oenococcus, and Weissella which were previously classified in the Leuconostocaceae.
As part of the Apollo 12 mission in November 1969, the camera from the Surveyor 3 probe was brought back from the Moon to Earth. On analyzing the camera, it was found that the common bacterium Streptococcus mitis was alive on the camera. NASA reasoned that the camera was not sterilized on Earth before the space probe's launch in April 1967, two and a half years earlier. However, later study showed that the scientists analysing the camera on return to Earth used procedures that were inadequate to prevent recontamination after return to Earth, for instance with their arms exposed, not covering their entire bodies as modern scientists would do. There may also have been possibilities for contamination during the return mission as the camera was returned in a porous bag rather than the airtight containers used for lunar sample return. As a result, the source of the contamination remains controversial.
Mycobacterium bohemicum is a species of the phylum Actinomycetota, belonging to the genus Mycobacterium.
Streptococcus oralis is a Gram positive viridans streptococcus of the Streptococcus mitis group. S. oralis is one of the pioneer species associated with eubiotic dental pellicle biofilms, and can be found in high numbers on most oral surfaces. It has been, however, found to be an opportunistic pathogen as well.
Sib RNA refers to a group of related non-coding RNA. They were originally named QUAD RNA after they were discovered as four repeat elements in Escherichia coli intergenic regions. The family was later renamed Sib when it was discovered that the number of repeats is variable in other species and in other E. coli strains.
Streptococcus constellatus is a species of Streptococcus bacteria that is part of the normal flora in the oral cavity, urogenital region, and intestinal tract. However, it can frequently cause purulent infections in other parts of the body. DNA homology studies and 16S rRNA sequence analysis demonstrate S. constellatus belongs to the Streptococcus anginosus group along with Streptococcus intermedius and Streptococcus anginosus.
Streptococcus equinus is a Gram-positive, nonhemolytic, nonpathogenic, lactic acid bacterium of the genus Streptococcus. It is the principal Streptococcus found in the alimentary canal of a horse, and makes up the majority of the bacterial flora in horse feces. Equivalence with Streptococcus bovis has been contested.
Thermomonosporaceae is a family of bacteria that share similar genotypic and phenotypic characteristics. The family Thermomonosporaceae includes aerobic, Gram-positive, non-acid-fast, chemo-organotrophic Actinomycetota. They produce a branched substrate mycelium bearing aerial hyphae that undergo differentiation into single or short chains of arthrospores. All species of Thermomonosporaceae share the same cell wall type, a similar menaquinone profile in which MK-9(H6)is predominant, and fatty acid profile type 3a. The presence of the diagnostic sugar madurose is variable, but can be found in most species of this family. The polar lipid profiles are characterized as phospholipid type PI for most species of Thermomonospora, Actinomadura and Spirillospora. The members of Actinocorallia are characterized by phospholipid type PII.
Enterococcus malodoratus is a species of the genus Enterococcus and a gram positive bacteria capable of opportunistic pathogenic response. These microbes have a thick polypeptide layer. Enterococcus can be found in the gastrointestinal tracts of humans and other mammals. In a study on the enterococcal flora of swine, E. malodoratus was found in the intestines and feces. It was not identified within the tonsils of swine, nor within cats, calves, dogs, horse, or poultry. The name "malodoratus" translates to "ill smelling".
Limosilactobacillus pontis is a rod-shaped, Gram-positive facultatively anaerobic bacterium. Along with other Lactobacillus species, it is capable of converting sugars, such as lactose, into lactic acid. Limosilactobacillus pontis is classified under the phylum Bacillota, class Bacilli, and is a member of the family Lactobacillaceae and is found to be responsible for the fermentation of sourdough, along with many other Lactobacillus species. This microorganism produces lactic acid during the process of fermentation, which gives sourdough bread its characteristic sour taste.
Lactiplantibacillus fabifermentans is a member of the genus Lactiplantibacillus and a type of lactic acid bacteria (LAB), a group of Gram-positive bacteria that produce lactic acid as their major fermented end product and that are often involved in food fermentation. L. fabifermentans was proposed in 2009 as a new species, after the type strain LMG 24284T has been isolated from Ghanaian cocoa fermentation. Analysis of the 16S rRNA gene sequence demonstrated that this species is a member of the Lactobacillus plantarum species group but further analysis demonstrated that it is possible to differentiate it from the nearest neighbors by means of DNA-DNA hybridization experiments, pheS sequence analysis, whole-cell protein electrophoresis, fluorescent amplified fragment length polymorphism analysis and biochemical characterization.
Streptococcus tigurinus is a novel member of the genus Streptococcus that was first discovered in 2012 by Swiss researchers.
Pharmacomicrobiomics, proposed by Prof. Marco Candela for the ERC-2009-StG project call, and publicly coined for the first time in 2010 by Rizkallah et al., is defined as the effect of microbiome variations on drug disposition, action, and toxicity. Pharmacomicrobiomics is concerned with the interaction between xenobiotics, or foreign compounds, and the gut microbiome. It is estimated that over 100 trillion prokaryotes representing more than 1000 species reside in the gut. Within the gut, microbes help modulate developmental, immunological and nutrition host functions. The aggregate genome of microbes extends the metabolic capabilities of humans, allowing them to capture nutrients from diverse sources. Namely, through the secretion of enzymes that assist in the metabolism of chemicals foreign to the body, modification of liver and intestinal enzymes, and modulation of the expression of human metabolic genes, microbes can significantly impact the ingestion of xenobiotics.
