Aggregation, adherence, anti-adhesion and antagonistic activity properties relating to surface charge of probiotic Lactobacillus brevis gp104 against Staphylococcus aureus
MICROBIAL PATHOGENESIS
Authors: Hojjati, Mohammad; Behabahani, Behrooz Alizadeh; Falah, Fereshteh
Abstract
Positive effects of fermented foods consumption on humans have stimulated lots of research attention. In this study, we investigated the probiotic potentials, antagonistic activities, and safety properties of Lactobacillus brevis gp104 isolated from Iranian traditional cheese. The results showed that the strain had high resistance to acidic conditions, simulated gastric and intestinal fluid. L. brevis gp104 was able to assimilate cholesterol from the medium; 41% in medium without bile salts and 58% in medium with bile salts. The potential of this strain was relatively low in phytate hydrolyzation and 62.02% hydrophobicity, 40.2% auto-aggregation, and 48.3% co-aggregation were observed. The adhesion value of L. brevis gp104 to adenocarcinoma Caco-2 cells was 13.4% that was also confirmed by scanning electron microscopy (SEM). Antibacterial effect of L. brevis fg104 was imposed against pathogenic strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa PTCC 1707, Salmonella typhimurium PTCC 1609, and Staphylococcus aureus ATCC 25923) and the most sensitive strain S. aureus. L. brevis gp104 was able to compete (52%), inhibit (47%) and displace (21%) the adhesion of S. aureus to Caco-2 cells. L. brevis gp104 did not show haemolytic or DNase activity, which confirms its safety aspects. Therefore, L. brevis gp104 was demonstrated promising properties for its potential health benefits for its application as novel biotherapeutic and bio-preservation agents.
Detecting and correlating bacterial populations to visual color change of polydiacetylene-coated filters
TALANTA
Authors: Zhang, Yueyuan; Dawson, Paul L.; Hanks, Timothy W.; Northcutt, Julie K.; Tzeng, Tzuen-Rong; Pennington, William T.
Abstract
Membrane filters were coated with 10,12-pentacosadiynoic acid (PCDA) then polymerized on the filter for rapid bacterial detection and quantification. The polymerized PCDA (pPDCA)-coated filter changed color in response to Salmonella Typhimurium and Escherichia coli but not to Listeria innocua. The time required for color change of pPCDA-coated filters was determined by a visual panel. A simple linear regression model was generated to fit the observed data and was validated with goodness of fit analysis and residual analysis. The pPCDA-filter method estimated Salmonella Typhimurium populations of 8 to 3 log CFU ml(-1) within 1.5-7.5 h, respectively.