User:Caitlinh918/sandbox

Lactobacillus rhamnosus is a bacterium that originally was considered to be a subspecies of L. casei, but later genetic research found it to be a species of its own. “Lactobacillus” is the name for a bacterium that produces lactic acid from the fermentation of carbohydrates. “Rhamnosus” is a latin word specifically created as an epithet for Lactobacillus. It is a short Gram-positive heterofermentative facultative anaerobic rod that often appears in chains. It makes ATP through aerobic respiration, but is also capable of using fermentation or anaerobic respiration if oxygen is absent. L. rhamnosus is non-motile, but has pilli as cellular appendages. On the surfaces of their pilli, mucin-binding proteins have been identified. The Lactobacillus rhamnosus and L. reuteri species are most commonly found in the healthy female genito-urinary tract and are most helpful to supplement in order to regain control over dysbiotic bacterial overgrowth during an active infection. It is considered a probiotic because of the way that it benefits improvement and control over bacterial overgrowth in the vagina, as well as its use in dairy products. Microbes like L. rhamnosus are important in the body because they take up the space that might otherwise be inhibited by harmful microorganisms. L. rhamnosus sometimes is used in yogurt and dairy products such as fermented and un-pasteurized milk and semi-hard cheese. While frequently considered a beneficial organism, L. rhamnosus may not be as beneficial to certain subsets of the population; in rare circumstances, especially those primarily involving weakened immune system or infants, there may be no advantage. There have been some studies showing a correlation between L. rhamnosus and alleviation of allergy symptoms, irritable bowel disease, bacterial vaginosis, and anxiety.

Genome
Lactobacillus rhamnosus has a wide variety of strains that have been isolated from many different environments including the vagina and gastrointestinal tract. L. rhamnosus strains have the capacity for strain-specific gene functions that are required to adapt to a large range of environments. Its core genome contains 2,164 genes, out of 4,711 genes in total (the pan genome). The accessory genome is overtaken by genes encoding carbohydrate transport and metabolism, extracellular polysaccharides, biosynthesis, bacteriocin production, pili production, the cassystem, the clustered regularly interspaced short palindromic repeat (CRISPR), loci, and more than 100 transporter functions and mobile genetic elements such as phages, plasmid genes, and transposons.

The genome of the specific strain L. rhamnosus LRB, in this case taken from a human baby tooth, consists of a circular chromosome of 2,934,954 bp with 46.78% GC content. This genome contains 2,749 total genes with 2,672 that are total protein-coding sequences. This sample did not contain any plasmids. The most extensively studied strain, L. rhamnosus GG, a gut isolate, consists of a genome of 3,010,111 bp. Therefore, the LRB genome is shorter than GG’s genome. LRB lacks the spaCBA gene cluster of GG and is not expected to produce functional pili (6). This difference may help explain why each strain lives in a different habitat.