RESUMEN
In silico analysis of Lactobacillus pentosus MP-10 plasmids (pLPE-1 to pLPE-5) suggests that plasmid-borne genes mediate the persistence of lactobacilli during olive fermentation and enhance their probiotic properties and their competitiveness in several ecological niches. The role of plasmids in the probiotic activities of L. pentosus MP-10 was investigated by plasmid-curing process which showed that plasmids contribute in increased metal tolerance and the biosequestration of several metals such as iron, aluminium, cobalt, copper, zinc, cadmium and mercury. Statistically significant differences in mucin adhesion were detected between the uncured and the cured L. pentosus MP-10, which possibly relied on a serine-rich adhesin (sraP) gene detected on the pLPE-2 plasmid. However, plasmid curing did not affect their tolerance to gastro-intestinal conditions, neither their growth ability under pre-determined conditions, nor auto-aggregation and pathogen co-aggregation were changed among the cured and uncured L. pentosus MP-10. These findings suggest that L. pentosus MP-10 plasmids play an important role in gastro-intestinal protection due to their attachment to mucin and, thus, preventing several diseases. Furthermore, L. pentosus MP-10 could be used as a bioquencher of metals in the gut, reducing the amount of these potentially toxic elements in humans and animals, food matrices, and environmental bioremediation.
Asunto(s)
Adhesinas Bacterianas/genética , Fermentación , Lactobacillus pentosus/genética , Olea/microbiología , Adhesinas Bacterianas/metabolismo , Genes Bacterianos , Lactobacillus pentosus/efectos de los fármacos , Lactobacillus pentosus/metabolismo , Metales Pesados/metabolismo , Metales Pesados/toxicidad , Mucinas/metabolismo , Plásmidos/genética , ProbióticosRESUMEN
Lactic acid bacteria isolated from indigenous milk of different animals were investigated for their efficacy, safety, and probiotic potential. The most potential isolate MMP4 was screened from mare's milk, which was further identified as Lactobacillus pentosus by using 16S rRNA gene sequencing and phylogeny. The probiotic potential of strain MMP4 was assessed by its ability to survive under acidic environment and in presence of bile salts along with the ability to inhibit food-borne as well as clinical pathogenic microorganisms such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Salmonella typhi. The phenol tolerance with cogent hydrophobicity to different hydrocarbons was demonstrated. Bile salt hydrolase activity of L. pentosus MMP4 was confirmed by detecting the Bsh gene by using colony PCR. The presence of Mub, Map, and EF-Tu genes involved in adhesion conferred the behavior of passage and adherence to gastrointestinal tract. Scanning electron microscopy of intestinal autopsy from albino mice revealed the attachment of bacterial cells on the mucus-lined intestinal walls against pathogens and further proved in vivo adhesion ability. The presence of intrinsic antibiotic resistance and lack of DNase, gelatinase, and hemolytic activity in MMP4 support its safety as probiotic traits. Thus, MMP4 bears an excellent and pragmatic properties for being used as probiotic and may be exploited in dairy industry.
Asunto(s)
Lactobacillus pentosus , Probióticos/farmacología , Animales , Adhesión Bacteriana , Ácidos y Sales Biliares/farmacología , Microbiología de Alimentos , Tracto Gastrointestinal/microbiología , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Lactobacillus pentosus/efectos de los fármacos , Lactobacillus pentosus/genética , Ratones , Pruebas de Sensibilidad Microbiana , Probióticos/efectos adversosRESUMEN
Lactobacillus pentosus K1-23 was selected from among 25 lactic acid bacterial strains owing to its high inhibitory activity against several pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, S. gallinarum, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium perfringens, and Listeria monocytogenes. Additionally, among 13 strains of Aureobasidium spp., A. pullulans NRRL 58012 was shown to produce the highest amount of ß-glucan (15.45 ± 0.07%) and was selected. Next, the optimal conditions for a solid-phase mixed culture with these two different microorganisms (one bacterium and one yeast) were determined. The optimal inoculum sizes for L. pentosus and A. pullulans were 1% and 5%, respectively. The appropriate inoculation time for L. pentosus K1-23 was 3 days after the inoculation of A. pullulans to initiate fermentation. The addition of 0.5% corn steep powder and 0.1% FeSO4 to the basal medium resulted in the increased production of lactic acid bacterial cells and ß-glucan. The following optimal conditions for solid-phase mixed culture were also statistically determined by using the response surface method: 37.84°C, pH 5.25, moisture content of 60.82%, and culture time of 6.08 days for L. pentosus; and 24.11°C, pH 5.65, moisture content of 60.08%, and culture time of 5.71 days for A. pullulans. Using the predicted optimal conditions, the experimental production values of L. pentosus cells and ß-glucan were 3.15 ± 0.10 × 108 CFU/g and 13.41 ± 0.04%, respectively. This mixed culture may function as a highly efficient antibiotic substitute based on the combined action of its anti-pathogenic bacterial and immune-enhancing activities.