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Bifidobacterium longumRANK: SpeciesTAXONOMY: Terrabacteria group -> Actinobacteria -> Actinobacteria -> Bifidobacteriales -> Bifidobacteriaceae -> Bifidobacterium -> Bifidobacterium longum OVERVIEW: 'Bifidobacterium longum' is a gram-positive, catalase-negative, rod-shaped bacterium present in the human gastrointestinal tract and one of the 32 species that belong to the genus Bifidobacterium. It is a micro-aerotolerant anaerobe and considered to be one of the earliest colonizers of the gastrointestinal tract of infants. When grown on general anaerobic medium, B. longum forms white, glossy colonies with a convex shape. While B. longum is not significantly present in the adult gastrointestinal tract, it is considered part of the gut flora and its production of lactic acid is believed to prevent growth of pathogenic organisms. B. longum is non- pathogenic and is often added to food products for its beneficial probiotic health effects. That B. longum subsp. thrives in secretor-fed infants is no surprise. It possesses both classes of fucosidases (GH95 and GH29) and was shown here to grow on 2′-fucosyllactose in vitro . Feces dominated by this subspecies also had lower percentages of fucosylated oligosaccharides remaining. However, why B. longum subsp. infantis failed to dominate in any non-secretor-fed infant is somewhat perplexing. It may be that B. longum subsp. infantis specializes in consuming 2′-fucosylated oligosaccharides to gain an advantage over other species. B. breve on the other hand seems to be an oligosaccharide generalist, as it was dominant in examples of infants fed by both types of milk. B. breve strains are known to be variable in their capacity to consume 2′-fucosylated oligosaccharides. [PMC 4412032] Three principal components of HMOS, 2′-fucosyllactose, lactodifucotetraose and 3-fucosyllactose, were consumed in these cultures. These three principal oligosaccharides of human milk were then individually tested as supplements for in vitro growth of four individual representative strains of infant gut microbes. Bifidobacterium longum JCM7007 and B. longum ATCC15697 efficiently consumed oligosaccharides and produced abundant lactate and short-chain fatty acids, resulting in significant pH reduction. The specificity of fermentation differed by microbe species and strain and by oligosaccharide structure. [PMC 3531294] B. longum is one of the more common strains of Bifidobacteria found in the GI tract. Its digestive benefits stem from its ability to break down carbohydrates and to scavenge and neutralize everyday toxins found in the gut. Preliminary research suggests that the antioxidant properties of this probiotic strain include the chelation of metal ions—especially copper—and the scavenging of free radicals. It is also supportive of immune health. Elderly patients administered B. longum showed heightened immune function for 20 weeks after discontinuing supplementation. This probiotic strain is the largest population of beneficial bacteria in babies. Sudo et al. demonstrated that germ-free (GF) mice with a sterile GI tract have an overactive HPA in response to stress. This hyper-response of the HPA is reversed by monoassociation with a single organism, Bifidobacterium infantis, which is a predominant bacterium in the infant gut and a commonly used probiotic organism. The exaggerated HPA stress response by GF mice was reversed by reconstitution with Bifidobacterium infantis.The amount of B. longum infantis in our guts decline as we age, but it remains an important part of our microflora. Supplementation with B. infantis has been shown to decrease bloating and bowel movement difficulty. Bifidobacterium animalis, B. longum-a, and B. pseudolongum deconjugate malonyl-, acetyl- and β-glucoside conjugates of daidzin, which are found in soy milk, to produce daidzein. These strains are also reported to transform daidzein to equol in soy milk [PMC 4381290]. When rats were given Bifidobacterium infantis orally, increased plasma tryptophan levels were observed. [PMID: 26598580 ] Identified as a constituent of the oral microbiome by Human Oral Microbiome Database. Identified as constituent of vaginal microbiome. [PMID 23282177] This species has been identified as a resident in the human gastrointestinal tract based on the phylogenetic framework of its small subunit ribosomal RNA gene sequences.[PMC 4262072] Evidence as psychobiotic, with benefits in IBD. [PMID: 23759244] Probiotic treatment resulted in normalization of the immune response, reversal of behavioral deficits, and restoration of basal norepinephrine concentrations in the brainstem. [PMID: 20696216] Germ-free mice exhibit hyper-responsive HPA axis activity following stress as compared to specific-pathogen free mice and this hyper-response of the HPA axis was reversed by Bifidobacterium infantis. B. infantis increased plasma tryptophan levels, decreased serotonin metabolite concentrations in the frontal cortex and dopamine metabolite concentrations in the amygdaloid cortex, both of which are implicated in depression. [PMC4315779] |