1,720,977 research outputs found
Cell wall components of a Lactobacillus brevis strain inhibit herpes simplex virus type 2 replication
No full textBacteria-free supernatant of Lactobacillus brevis strain CD2 grown in cell culture medium inhibits herpes simplex virus type 2 (HSV-2) replication in cell culture independently from H2O2 or lactic acid. The mechanisms of action and the bacterial factors responsible for the antiviral effect were studied using bacterial extracts obtained by sonication of L. brevis cells or by lysozyme/antibiotic treatment of the microorganism. The antiviral activity of bacterial cell wall was also studied. Bacterial extract and cell wall were not toxic to cells at the maximal concentration tested (3 mg/ml protein). Both the extract and the cell wall fraction showed a dose-dependent inhibitory activity on HSV2 multiplication when present on Vero cells before virus adsorption and during infection.
The inhibition was exerted on the first phases of virus replication cycle. The inhibitory activity was resistant to a 30 minutes treatment at 100°C. DNA and lipids obtained from bacterial extract were devoid of any inhibitory effect. S-layer of bacterial cell-wall containing several heat-resistant molecules (teichoic and lipoteichoic acids, lipoglycans, teichuronic acids and other acidic or neutral polysaccharides) was removed by treatment with LiCl without affecting bacterial viability. Bacterial extract and cell-wall fragments obtained after LiCl treatment showed a dramatic reduction in the antiviral activity suggesting that cell wall components of L. brevis released in bacterial supernatant after sonication or lysozyme/antibiotic treatment are responsible for the inhibiting activity against HSV-2
Effects of processing on the organoleptic and nutritional properties of blueberry–derived products
No full textChemistry, stability and bioavailability of resveratrol
No full textResveratrol is a bioactive polyphenol found in many vegetables. It is well known for its multiple pharmacological activities, such as anti-inflammatory, antioxidant, antimicrobial, anticancer, neuroprotective and cardioprotective effects. In vitro evidence of resveratrol efficacy is widespread, however, many concerns regarding its effectiveness in vivo arise from its poor stability in vitro and bioavailability following oral ingestion. This review focuses on the in vitro stability, with special focus on the photochemical stability of resveratrol, and on the therapeutic perspectives of this molecule due to its low bioavailability
Antiviral activity of Lactobacillus brevis towards herpes simplex virus type 2: Role of cell wall associated components
No full textThe aim of this research was to study the mechanisms of Lactobacillus brevis antiviral activity towards HSV-2 and to identify the bacterial components responsible for the inhibiting effect. Bacterial extract and cell walls were prepared by lysozyme digestion of L brevis cells untreated or treated with LiCI to remove S-layer proteins. Bacterial extract and cell wall fragments showed a dose dependent inhibitory effect on HSV-2 multiplication. In order to characterize the inhibitory activity of L brevis, the bacterial extract was subjected to different physical and chemical treatments. The inhibitory activity was resistant to high temperature and proteases digestion and appeared to be associated with compounds with a molecular weight higher than 10 kDa. DNA, RNA and lipids isolated from bacterial cells were devoid of inhibitory effect. The antiviral activity of both bacterial extract and cell wall fragments obtained from L brevis cells after the S-layer removal was significantly reduced compared to untreated cells suggesting that the inhibitory activity is likely due to a heat-resistant non-protein cell surface bacterial component. (C) 2011 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Effects of methanolic extract of sour cherry (Prunus cerasus L.) on microbial growth
No full textThe antimicrobial activity of a methanolic extract of the common edible fruit Prunus cerasus L. was evaluated. HPLC analysis of the extract revealed the abundant presence of anthocyanins. Minimum Inhibitory Concentrations (MIC) for Gram-positive and Gram-negative pathogenic bacteria was in the range 26.6 mg mL-1, whereas the time-kill assay revealed that the bactericidal effect was exerted only at concentrations higher than 2X MIC. Interestingly, at concentrations lower than MIC, P.similar to cerasus L. extract exerted a stimulating effect on bacterial proliferation and on the ability to form biofilms. In particular, a multidrug-resistant Acinetobacter baumannii strain showed a 30% increase in growth at low concentrations. In the light of this finding, we speculate that the use of berry extracts (rich in anthocyanins) may present some risks to human health when used as preservatives in food and cosmetic products
Inhibition of amyloid peptide fragment Aβ25-35 fibrillogenesis and toxicity by N-terminal β-amino acid-containing esapeptides: is taurine moiety essential for in vivo effects?
No full textDEVELOPMENT OF A REAL-TIME PCR ASSAY FOR THE ASSESSMENT OF PROBIOTIC Lactobacillus brevis CD2 STRAIN PERSISTENCE IN ORAL CAVITY
No full textDental caries and periodontal disease occur in almost 95% of the population. Although the use of probiotics to improve oral health is still in its infancy, many clinical trials are ongoing in this field.The aim of this study is to select the optimal conditions for quantification in the oral cavity of Lactobacillus brevis CD2, a probiotic strain contained in the commercially available dietary supplement Inersan® and to assess its persistency after oral administration. Different sets of primers for L. brevis detection have been tested in real-time PCR reactions to find optimal amplification efficiency and target specificity. Primers ability in the identification of L. brevis DNA was assessed in a pilot study conducted on 12 healthy volunteers clinically free of oral pathologies. The subjects took 3 tablets/day for 3 days and one tablet the 4th day. Clinical samples (dorsal surface of tongue, first molar, vestibular fornix and saliva) were collected at baseline (before beginning the trial), at T0 (in the morning before the assumption of the last tablet) and 3, 6, and 9 hours after taking the last tablet. The quantities of L. brevis DNA were compared to the total number of bacteria present in the samples. The activity of the enzyme arginine deiminase, responsible for oral pH homeostasis (particularly abundant in the CD2 strain) was also assessed in the saliva samples before and after treatment by HPLC measurements. Enzymatic analyses revealed that arginine deiminase activity was higher at T0 and at 3 hours than at 6-9 hours.We observed absence of tooth colonization by L. brevis at each time point, whereas its amount in the other oral sites was inversely correlated with elapsed time from the assumption. Persistence was maximal 3 hours after administration of tablets, but decreased more than one hundred times at 6 hours. However, the overnight recovery was significantly better than that obtained during the day, suggesting that probiotics administration before night could result in a better effectiveness
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