1,721,037 research outputs found
Lactobacilli as Anti-biofilm Strategy in Oral Infectious Diseases: A Mini-Review
Full text linkThe spread of biofilm-related diseases in developed countries has led to increased mortality rates and high health care costs. A biofilm is a community of microorganisms that is irreversibly attached to a surface, behaving very differently from planktonic cells and providing resistance to antimicrobials and immune response. Oral diseases are an excellent example of infection associated with the formation of highly pathogenic biofilms. It is generally accepted that, when the oral homeostasis is broken, the overgrowth of pathogens is facilitated. Among them, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are the main etiological agents of periodontitis, while Streptococcus mutans is strongly associated with the onset of dental caries. Other microorganisms, such as the fungus Candida albicans, may also be present and contribute to the severity of infections. Since the common antibiotic therapies usually fail to completely eradicate biofilm-related oral diseases, alternative approaches are highly required. In this regard, the topical administration of probiotics has recently gained interest in treating oral diseases. Thus, the present mini-review focuses on the possibility of using Lactobacillus spp. as probiotics to counteract biofilm-mediated oral infections. Many evidence highlight that Lactobacillus living cells can impede the biofilm formation and eradicate mature biofilms of different oral pathogens, by acting through different mechanisms. Even more interestingly, lactobacilli derivatives, namely postbiotics (soluble secreted products) and paraprobiotics (cell structural components) are able to trigger anti-biofilm effects too, suggesting that they can represent a novel and safer alternative to the use of viable cells in the management of biofilm-related oral diseases
THE HEALTH-PROMOTING EFFECT OF EXTRACELLULAR VESICLES RELEASED BY VAGINAL LACTOBACILLI
No full textLactobacilli (LB) species dominate the vaginal microflora performing a first line defence against infections (1).
Lactobacilli metabolites mediate the health-promoting effect acting as antimicrobials or are used for quorum-sensing
and cross-talk communication (2). In this sense, extracellular vesicles (EVs) from LB demonstrate an antimicrobial
activity (3,4), modulate host’s nervous and immune system (5) and induce apoptosis in cancerous liver
cells (6). Notably, EVs derived from vaginal LB isolates reduce HIV-1 infection (7). Here, we investigate the
health-promoting activity of EVs produced by two strains of LB isolated from human vagina (L. gasseri BC12
and L. crispatus BC5) in terms of anti-adhesive effect on pathogens and pro-adhesive effect on LB. EVs were
recovered from LB cultures by ultracentrifuge cycles and yield (1010 EVs/mL), size (90-150 nm diameter) and
protein content were characterized. Adhesion assays, performed on HeLa cells monolayer, demonstrated that
LB-EVs were able to reduce at least 25% the adhesion of all pathogens tested: Escherichia coli, Staphylococcus
aureus, Enterococcus faecalis and Streptococcus agalactiae. Moreover, LB-EVs stimulated more than 26%
the adhesion of all LB strains, including the same producer strains and two other vaginal isolates belonging to
the same species (L. gasseri BC9, BC13 and L. crispatus BC1, BC3). L. gasseri BC12 EVs demonstrated the
best health-promoting profile. These results highlighted that the barrier effect exerted by lactobacilli can be
mediated by EVs released in the vaginal environment. This opens to the hypothesis of using postbiotics from
human vaginal bacteria as a new strategy to prevent/treat human infections
Genotypic and phenotypic characterization of Lactobacillus strains with antipathogenic activities
No full textLactobacillus crispatus BC5 and Lactobacillus gasseri BC12 possess antipathogenic activities that makes them good candidates as probiotics. Indeed, it has been demonstrated that these Lactobacilli can carry out a fungistatic and fungicidal activities against Candida albicans, inhibit the Chlamydia trachomatis infectivity, reduce the Neisseria gonorrhoeae viability and inhibit HIV-1 replication.
The aim of this study is to characterize L. crispatus and L. gasseri from genotypic and phenotypic point of views.
Whole genome sequencing was performed followed by gene annotation, genome comparison and single gene analysis, with a specific focus on genes involved in antibiotic resistance and production of antimicrobial compounds. Phenotypic characterization was performed using Phenotype Microarray, revealing carbon and nitrogen sources used by these two strains as well as their specific sensitivity to several drugs and chemical compounds. Functional assays demonstrated the capacity of Lactobacillus biosurfactants to eradicate and inhibit the biofilm formation of methicillin resistant S. aureus (MRSA). Taken together, these results demonstrate that L. crispatus and L. gasseri having possible biotechnological applications, in particular, for the treatment and/or prevention of pathogen infections
Exopolysaccharides released by vaginal Lactobacillus strains: chemical characterization and modulation of biofilm formation.
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Development of soy-yoghurts, containing functional vaginal lactobacilli and their investigation after digestion using postmenopausal donors
No full textInsight into phenotypic and genotypic differences between vaginal Lactobacillus crispatus BC5 and Lactobacillus gasseri BC12 to unravel nutritional and stress factors influencing their metabolic activity
Full text linkThe vaginal microbiota, normally characterized by lactobacilli presence, is crucial for vaginal health. Members belonging to L. crispatus and L. gasseri species exert crucial protective functions against pathogens, although a total comprehension of factors that influence their dominance in healthy women is still lacking. Here we investigated the complete genome sequence and
comprehensive phenotypic profile of L. crispatus strain BC5 and L. gasseri strain BC12, two vaginal strains featured by antibacterial and anti-viral activities. Phenotype microarray (PM) results revealed an improved capacity of BC5 to utilize different carbon sources as compared to BC12, although some specific carbon sources that can be associated to the human diet were
only metabolized by BC12, i.e. uridine, amygdalin, tagatose. Additionally, the two strains were mostly distinct in the capacity to utilize the nitrogen sources under analysis. On the other hand, BC12 showed the tolerance/resistance towards twice the number of stressors (i.e. antibiotics, toxic metals etc.) with respect to BC5. The divergent phenotypes observed in PM were supported by the identification in either BC5 or BC12 of specific genetic determinants that were found to be part of the core genome of each species. The PM results in combination with comparative genome data provide insights into the possible environmental factors and genetic traits supporting the predominance of either L. crispatus BC5 or L. gasseri BC12 in the vaginal niche, giving
also indications for metabolic predictions at the species level
Histone post-translational modifications by HPLC-ESI-MS after HT29 cell treatment with HDAC inhibitors
No full textThe goal of the present work is to establish a correlation between the degree of histone post-translational modifications and the effects caused by treatment of HT29 colon cancer cells with class I-selective (MS-275 and MC1855), class II-selective (MC1568), and non-selective (suberoylanilide hydroxamic acid (SAHA) histone deacetylase inhibitors (HDACi). This correlation could afford a mean to better understand the mechanism of action of new, more potent, and selective HDACi directly on the cells. To this end, LC coupled to MS was applied in studies of time and concentration-dependent treatment with HDACi in HT29 cells. The results were correlated to their potency of histone deacetylase inhibition and to their effects on the cell cycle. The results indicate that the four tested inhibitors show a different pattern of time- and concentration-dependent modification after treatment of HT29 cells. At the selected concentrations, they cause different histone hyperacetylation and different cell cycle effects. In particular, SAHA (non-selective HDACi) affected hyperacetylation of all histones and caused massive cell death. MC1855 (class I-selective HDACi, hydroxamate) proved to be more potent and less toxic (cell arrest in G2/M phase) than SAHA. MS-275 (class I-selective HDACi, benzamide) exhibited a higher degree of hyperacetylation of H4 and a lower degree of H2A, H2B, and H3 acetylation, causing a cell arrest in G0/G1 phase. On the contrary, MC1568 (class II-selective HDACi) produced only a modest hyperacetylation of H4, was ineffective on the other histones, and showed no effect on cell cycle in HT29 cells
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