Effect of a probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid-induced colitis in rats.

This study aimed to investigate the potential effects of an oral treatment by a newly isolated probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid (TNBS)-induced colitis in Wistar rats. Thus, 18 rats were divided into three groups (n = 6 per group): group 1 (control) - rats not receiving TNBS application; group 2 - rats receiving an intrarectal TNBS infusion (100 mg/kg TNBS dissolved in ethanol); and group 3 - rats treated with intragastrical TN8 strain once per day (for 5 days before TNBS induction). The performance and the effects of the probiotic treatment were evaluated using a series of histological, biophysical and biochemical analyses. The results have shown that the treatment with the L. plantarum TN8 strain improves the body weight and reduces the diarrhoea, colonic mucosal inflammation and colon shortening. TN8-treated rats showed a significant decrease in the total cholesterol content from 1.86 (for group 2) to 1.32 mmol/l and in triglyceride (TG) content from 2.09 (for group 2) to 1.23 mmol/l. Furthermore, the findings revealed that the high-density lipoprotein (HDL) cholesterol contents increased from 0.95 to 1.02 mmol/l. The histological studies have confirmed that the architecture of the liver and kidney tissues of the TN8-treated rats were found to be improved. Overall, the results suggest that the L. plantarum TN8 presents promising perspectives for the development of safe and cost-effective agents for the prevention or alleviation of several intestinal pathologies.

Wool-waste valorization: production of protein hydrolysate with high antioxidative potential by fermentation with a new keratinolytic bacterium, Bacillus pumilus A1.

AIMS: Wool, a recalcitrant waste mainly composed of keratin, constituted a serious problem for the environment and was not effectively valorized. This study reported the optimization of wool-waste biodegradation by a new keratinolytic bacterium Bacillus pumilus A1. The in vitro digestibility and the antioxidant potential of wool protein hydrolysate (WPH) were also investigated. METHODS AND RESULTS: The antioxidant potential of WPH was evaluated using in vitro antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power and metal (Fe(2+)) chelating activity. Cultivation on 50 g l(-1) of wool for 2 days, at 45°C and at initial pH of 10, resulted in maximum production of amino acids and peptides (39.7 g l(-1)). WPH presented a very high in vitro digestibility (97%) as compared with that of the untreated wool (3%). CONCLUSIONS: The keratin present into the wool-waste was completely solubilized. Interestingly, WPH presented an important DPPH radical-scavenging activity with an IC50 value of 0.14 ± 0.01 mg ml(-1). SIGNIFICANCE AND IMPACT OF STUDY: WPH would be a very useful source of protein and antioxidants in animals' diets.

Partial purification and characterization of chiIO8, a novel antifungal chitinase produced by Bacillus cereus IO8.

AIMS: To investigate the distribution of chitinase IO8 in Bacillus cereus strains, the enhancing effects of the chitinase-producing B. cereus strains on biocontrol potential by dual culture assay and in vivo assay against Botrytis cinerea and also the enhancing effects of the chiIO8 on disinfectant properties against seed-borne diseases. Moreover, the application of chiIO8 treatment was also observed to improve the germinative energy. METHODS AND RESULTS: The purification steps included ammonium sulfate precipitation, with columns of DEAE-Sepharose anion-exchange chromatography and Sephacryl S-400 high-resolution gel chromatography. The method gave a 5.8-fold increase in the specific activity and had a yield of 17%. The molecular weight of the partially purified chitinase chiIO8 was found to be around 30 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal pH and optimal temperature of the partially purified chitinase were pH 6.5 and 65°C, respectively. The thermostable chitinase still retained the activity after incubation for 100 min at 65°C, and it was increased about 1.25 times than that of the control (before heating) when the enzyme solution heated at 65°C for 60 min. The partially purified chitinase chiIO8 displays a wide inhibitory spectrum towards all phytopathogenic fungi tested. chiIO8 also exhibited effective disinfectant properties against seed-borne diseases. CONCLUSION: The present investigation emphasizes the potential of chitinase-producing micro-organism as promising biocontrol agents of fungal plant pathogens with chitinous cell wall. The novel chitinase chiIO8 proved an efficient, environmentally safe and user-friendly solution. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first investigation devoted exclusively to analyse the distribution of chitinase in B. cereus. It infers that the chitinase produced by B. cereus might play a role in the activity of the biopesticide.

Patterning of polystyrene by scanning electrochemical microscopy. Biological applications to cell adhesion.

Polystyrene surfaces may be patterned by Ag(II), NO(3)(•), and OH(•) electrogenerated at the tip of a scanning electrochemical microscope. These electrogenerated reagents lead to local surface oxidation of the polymer. The most efficient surface treatment is obtained with Ag(II). The patterns are evidenced by XPS and IR and also by the surface wettability contrast between the hydrophobic virgin surface and the hydrophilic pattern. Such Ag(II) treatment of a polystyrene Petri dish generates discriminative surfaces able to promote or disfavor the adhesion of proteins and also the adhesion and growth of adherent cells. The process is also successfully applied to a cyclo-olefin copolymer and should be suitable to pattern any hydrogenated polymer.