Search results for "BIOTIC"
showing 10 items of 1505 documents
Probiotics and oral health : a systematic review
2017
Background Probiotics are microorganisms, mainly bacteria, which benefit the host’s health. Many studies support the role of probiotics as a contributor to gastrointestinal health, and nowadays many authors are trying to prove its influence in oral health maintenance. Objectives To review the published literature with the purpose of knowing the importance of using probiotics as a preventive and therapeutic method for oral infectious diseases management. Material and Methods An electronic search in PubMed database with the keywords “oral health AND probiotics AND dentistry” was conducted. The inclusion criteria were: randomized clinical trials (RCTs) that assess the action of any probiotic s…
Circadian Rhythm and Concentration of Melatonin in Breast Cancer Patients
2020
Background: Melatonin is a biomarker of the central circadian clock and its chronobiotic actions entraining circadian rhythms to the light-dark cycle are well known. Reduction in melatonin levels and altered circadian rhythms have been associated with a high risk of breast cancer. Melatonin has also shown to display anti-proliferative effects on breast cancer growth and proliferation. Evaluation of melatonin circadian rhythm alterations in patients bearing breast cancer may have interesting prognostic and therapeutic applications. Objective: To review studies evaluating the circadian rhythm of melatonin in breast cancer patients. The effects of surgery and chemotherapy on melatonin secreti…
Antibiotics Resistance in Enterococcus Isolates from Poultry Waste
2020
Abstract The aim of the study was to evaluate the drug resistance of Enterococcus faecalis and Enterococcus faecium isolated from different types of poultry waste. The study material consisted of feather samples (duck, turkey, chicken), sludge and centrifuge sediment, originating from three poultry farms. The study was conducted in two stages; isolation and identification of Enterococcus bacteria from the waste and evaluation of their drug resistance using Kirby-Bauer method. Contamination of the poultry waste with Enterococcus isolates included E. faecium species (79 %) and E. faecalis (21 %). The most contaminated were sludge and sediment from the centrifuge as well as chicken feathers, i…
Human milk and mucosa-associated disaccharides impact on cultured infant fecal microbiota
2020
Human milk oligosaccharides (HMOs) are a mixture of structurally diverse carbohydrates that contribute to shape a healthy gut microbiota composition. The great diversity of the HMOs structures does not allow the attribution of specific prebiotic characteristics to single milk oligosaccharides. We analyze here the utilization of four disaccharides, lacto-N-biose (LNB), galacto-N-biose (GNB), fucosyl-α1,3-GlcNAc (3FN) and fucosyl-α1,6-GlcNAc (6FN), that form part of HMOs and glycoprotein structures, by the infant fecal microbiota. LNB significantly increased the total levels of bifidobacteria and the species Bifidobacterium breve and Bifidobacterium bifidum. The Lactobacillus genus levels wer…
Conjugative ESBL plasmids differ in their potential to rescue susceptible bacteria via horizontal gene transfer in lethal antibiotic concentrations.
2017
Conjugative ESBL plasmids differ in their potential to rescue susceptible bacteria via horizontal gene transfer in lethal antibiotic concentrations
Production Conditions Affect the In Vitro Anti-Tumoral Effects of a High Concentration Multi-Strain Probiotic Preparation.
2016
A careful selection of the probiotic agent, standardization of the dose and detailed characterization of the beneficial effects are essential when considering use of a probiotic for the dietary management of serious diseases. However, changes in the manufacturing processes, equipment or facilities can result in differences in the product itself due to the live nature of probiotics. The need to reconfirm safety and/or efficacy for any probiotic product made at a different factory is therefore mandatory. Recently, under the brand VSL#3®, a formulation produced by a manufacturer different from the previous one, has been commercialized in some European countries (the UK and Holland). VSL#3 is a…
Pyomelanin-producingPseudomonas aeruginosaselected during chronic infections have a large chromosomal deletion which confers resistance to pyocins
2016
When bacterial lineages make the transition from free-living to permanent association with hosts, they can undergo massive gene losses, for which the selective forces within host tissues are unknown. We identified here melanogenic clinical isolates of Pseudomonas aeruginosa with large chromosomal deletions (66 to 270 kbp) and characterized them to investigate how they were selected. When compared with their wild-type parents, melanogenic mutants (i) exhibited a lower fitness in growth conditions found in human tissues, such as hyperosmolarity and presence of aminoglycoside antibiotics, (ii) narrowed their metabolic spectrum with a growth disadvantage with particular carbon sources, includin…
Chance and necessity in the genome evolution of endosymbiotic bacteria of insects.
2017
An open question in evolutionary biology is how does the selection–drift balance determine the fates of biological interactions. We searched for signatures of selection and drift in genomes of five endosymbiotic bacterial groups known to evolve under strong genetic drift. Although most genes in endosymbiotic bacteria showed evidence of relaxed purifying selection, many genes in these bacteria exhibited stronger selective constraints than their orthologs in free-living bacterial relatives. Remarkably, most of these highly constrained genes had no role in the host–symbiont interactions but were involved in either buffering the deleterious consequences of drift or other host-unrelated function…
Human milk and mucosal lacto- and galacto-N-biose synthesis by transgalactosylation and their prebiotic potential in Lactobacillus species.
2017
Lacto-N-biose (LNB) and galacto-N-biose (GNB) are major building blocks of free oligosaccharides and glycan moieties of glyco-complexes present in human milk and gastrointestinal mucosa. We have previously characterized the phospho-β-galactosidase GnbG from Lactobacillus casei BL23 that is involved in the metabolism of LNB and GNB. GnbG has been used here in transglycosylation reactions, and it showed the production of LNB and GNB with N-acetylglucosamine and N-acetylgalactosamine as acceptors, respectively. The reaction kinetics demonstrated that GnbG can convert 69 ± 4 and 71 ± 1 % of o-nitrophenyl-β-d-galactopyranoside into LNB and GNB, respectively. Those reactions were performed in a s…
Toxicological implications of enzymatic control of reactive metabolites.
1990
Many foreign compounds are transformed into reactive metabolites, which may produce genotoxic effects by chemically altering critical biomolecules. Reactive metabolites are under the control of activating, inactivating and precursor sequestering enzymes. Such enzymes are under the long-term control of induction and repression, as well as the short-term control of post-translational modification and low molecular weight activators or inhibitors. In addition, the efficiency of these enzyme systems in preventing reactive metabolite-mediated toxicity is directed by their subcellular compartmentalization and isoenzymic multiplicity. Extrapolation from toxicological test systems to the human req…