1,721,143 research outputs found
Disentangling the complex relationship between food microbiota and gut microbiome: an update
No full textThe relationship between food and gut microbiota is complex and multifaceted, playing a significant role in
human health. Food like fermented foods can contain indigenous beneficial microbes, microbial metabolites,
and other bioactives, which are harnessed to target gut microbiota and play a significant role in human health
and well-being. Therefore, food microbiota can offer an affordable dietary intervention strategy being involved
in the reduction of a risk factor such as cholesterol and trimethylamine oxide (TMAO) and the production of healthimproving factors such as folate, gamma-aminobutyric acid (GABA), conjugated linoleic acids (CLA), exopolysaccharides (EPS), short-chain fatty acids, etc. On the other hand, it has to be considered that probiotics
exhibit significant variability in their engraftment within the gut microbial community, occurring in some subjects
but not in others. Studying the interaction between food and gut microbiome is becoming increasingly crucial in
this scenario. As basic research continues to unveil the effects of various novel dietary components and their
microbial byproducts on the gut microbiome, the extent of their efficacy in enhancing gut health and addressing
gastrointestinal diseases awaits clarification through population studies employing the microbiome, probiotics,
and epidemiology approach
L-leucine auxotrophy in Bifidobacterium globosum
No full textThe enzymes involved in the biosynthetic pathway of L-leucine were studied in plasmid-negative and plasmid-positive clones derived from the RU 809 strain of the Bifidobacterium globosum species. The growth of plasmid-positive clones in synthetic medium required L-leucine. We have shown that no detectable activity of the β-isopropylmalate dehydrogenase enzyme was present in plasmid-positive clones, whereas detectable and significant activity of this enzyme was found in plasmid-negative clones. The lack of activity of the β-isopropylmalate dehydrogenase enzyme is considered responsible for the L-leucine auxotrophy in the plasmid-positive clones
Isolation, cultivation and characterization of new bifidobacterial species
No full textBifidobacteria are important probiotic bacteria and the number of identified species of the genus Bifidobacterium is greatly increased in recent years mainly due to the study on poor investigated animal gastrointestinal niches. Thanks to the modern omics tools used for phylogenomic and genomic approaches, understanding host-bifidobacteria interactions (antibiotic resistance, adherence and biofilm formation as well as fitness, survival, and immunological functions) is becoming easier, allowing for more thorough molecular characterization. In this scenario on the other hand conventional microbial culture methods and identification processes for its accurate identification and characterization are not surpassed. Classical bacteriological studies targeted to one genus should be encouraged in order to accumulate isolates and their ecological, phenotypical and genotypical details: this is an important opportunity for useful, publishable, contributions to knowledge and to taxonomy and as support to molecular data and viceversa. For example, molecular data about the presence of bifidobacterial species in host microbiota where until now these species have not yet been isolated is a stimulus to unravel new findings. The addition of new species description should be considered not simply for academic validity, but also for their impact on applied microbiology especially for those species considered probiotics. The finding of recently new 23 bifidobacterial species in non-human primates, the most evolutionary closed species to humans, could be of great interest to obtain useful information also for human beings. Proposals for new species should include a suggested scheme for routine identification, and some reasonable basis for prediction of ecological, functional and technological properties as described in the Minimal Standards for new species description of Bifidobacterium, Lactobacillus and related genera. These requirements would provide a practical basis for the work in the routine laboratory. Academic taxonomists play an important role supplying expertise for probiotic applications because taxonomy should be the “working technical language of microbiology”
Bifidobacterium ruminantium sp. nov. and Bifidobacterium merycicum sp. nov. from the rumens of cattle
No full textAmong several hundred bifidobacteria isolated from bovine rumens, eight strains were recognized primarily on the basis of DNA-DNA hybridization results as members of two new distinct DNA homology groups. We studied the morphology, oxygen, carbon dioxide, temperature, and pH requirements, fermentation patterns, end products of glucose fermentation, biochemical reactions, protein electrophoretic patterns, isozyme patterns, DNA homology relationships, and guanine-plus-cytosine contents of these organisms, and we propose that these two groups of strains should be considered new species, Bifidobacterium ruminantium (type strain, strain ATCC 49390) and Bifidobacterium merycicum (type strain, strain ATCC 49391)
Influence of aminoacid requirement on the growth of Bifidobacterium globosum strains
No full textA general procedure has been devised for the determination of aminoacid requirements in Bifidobacterium globosum strains, based upon identification of individual aminoacids singularly deprived of the defined synthetic medium. In the plasmid-positive and plasmid-negative clones of RU 809 and T 19 strains, we found a correlation between the presence of plasmid and L-leucine auxotrophy. This characteristic is not shared by the other 145 strains, 26 of which are plasmid-positive, of the B. globosum species
Chemotaxonomic Features in the Bifidobacteriaceae Family
No full textChemotaxonomy studies the chemical variation in microbial cells and the use of chemical characteristics in the
classification and identification of bacteria; it can be very helpful in the modern approach of bacterial polyphasic
taxonomy. For some groups it is one of the most important taxonomic criteria for identification (e.g., Sphingomonas
sp.; Busse et al., 1999) while for others, such as Bifidobacteriaceae, it is important but not sufficient for strain identification.
It has been recommended in the Bifidobacteriaceae Minimal Standard guidelines for the description of new
species (Mattarelli et al., 2014).
Chemotaxonomic markers applied in polyphasic approach of Bifidobacteriaceae are here described singularly
Identification of bifidobacteria from fermented milk products
No full textSix samples of fermented milk preparations were examined for the presence of bifidobacteria. Identification was based on fermentation tests, genetic relatedness studies and electrophoretic analysis. Contrary to label information, Bifidobacterium animalis was the only species present
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