Promising Probiotic Strain Research Articles

Lactic acid bacteria isolated from yak milk show probiotic potential.

Probiotic industries strive for new, efficient and promising probiotic strains that impart a positive impact on consumer health. Challenges are persisting in isolation, screening, and selection of the new indigenous probiotic strains. In the present research, we explored the probiotic potential of 17 lactic acid bacteria isolated from Yak milk in a series of in vitro tests. We also demonstrated their health benefits, i.e., cholesterol degradation, lactose digestion, antimicrobial activity, antioxidant, and anticancer activities. Principal component analysis revealed that more than 50% of the strains fulfilled the examined criteria, e.g., survival in acidic pH, bile concentrations, and adherent property. Approximately all the strains produced antimicrobial substances against the maximum number of tested strains including clinical strains. Most strains degraded cholesterol in comparison to the reference probiotic strain whereas strain Yc showed 1.5 times higher the degradation efficiency of the control strain. Lan4 strain exhibited remarkable anticancer activity and induced the maximum apoptosis (87%) in the Hela cells and was non-toxic to the non-cancerous HEK293 cells. Around ten strains showed positive lactose digestion. Overall, this can be concluded that selected lactic acid bacteria revealed excellent probiotic properties along with desirable health benefits. These strains need to be further investigated in details for their application in the development of novel probiotic preparations for the improvement of public health.

Improved growth rate and disease resistance in olive flounder, Paralichthys olivaceus, by probiotic Lactococcus lactis WFLU12 isolated from wild marine fish

The use of probiotics is a strategy employed to improve host health status and to prevent infectious diseases. The current study was aimed at investigating the diversity of lactic acid bacteria (LAB) and Bacillus species in the gastrointestinal tracts of wild marine fishes, as well as the beneficial effects of Lactococcus lactis WFLU12 as a host-derived probiotics in olive flounder. In marine fishes, wild olive flounder and rock bream were shown to be good sources of LAB and Bacillus isolation, respectively. Some isolates, including the strain WFLU12, have shown stronger inhibitory activity against various aquatic bacterial pathogens and more tolerance to low pH and bile acids compared to some strains isolated from sources other than marine. Lc. lactis WFLU12 was found to confer to olive flounder protection against streptococcosis caused by Streptococcus parauberis through competitive exclusion and increased innate immune responses. Interestingly, the natural infection rate in the probiotic fed group (33%=10/30) was significantly lower than that in the control group (60%=18/30). None of the nisin Z and colicin V-producing probiotic-fed fish were naturally infected by S. parauberis during the feeding period. In addition, more importantly, this promising probiotic strain significantly promoted fish growth along with better feed conversion and specific growth rate. This study demonstrates that the use of host-derived probiotics can offer a significant advantage in terms of optimum survival and function in the gastrointestinal tract of the intended host. Statement of relevanceIn this study, host-derived probiotic strain outperforms elimination of pathogen through competitive exclusion in the gastrointestinal tract and increased innate immune responses. More importantly, this promising probiotic strain significantly promoted fish growth along with better feed conversion. This study will provide insight into how optimal probiotics should be selected and developed. It might facilitate the replacement of commercial fish probiotic products originated from terrestrial sources with host-derived probiotics in the near future.

Development of putative probiotics as feed additives: validation in a porcine-specific gastrointestinal tract model.

Enforced restrictions on the use of antibiotics as growth promoters (AGPs) in animal production have prompted investigations into alternative feed additives in recent decades. Probiotics are currently the main feed additive used in livestock. However, the selection of probiotic candidates relies on human-based methods and little is known about the verification criteria for host-specific selection. We investigated the probiotic potential of Lactobacillus salivarius strains isolated from fed pig feces for their use as porcine feed additives. Two methods were developed that simulated the pig gastrointestinal (GI) tract and the intestinal epithelium, and these were compared with human-based in vitro methods and used for selecting porcine probiotics. Lactobacillus salivarius strain LS6 was identified as a promising probiotic strain for potential use as a porcine feed additive. This strain prevented disruption of the epithelial integrity of pig small intestine (PSI) cells by inhibiting the adherence of enterotoxigenic Escherichia coli K88. It also showed high survival rates in the in vitro pig GI tract model and good adhesion to PSI cells. We propose that host target-specific screening and validation methods are important tools in the development of effective probiotic feed additives, and this approach may support future-oriented agriculture.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-016-7812-1) contains supplementary material, which is available to authorized users.

Proteomic Profiling of Bifidobacterium bifidum S17 Cultivated Under In Vitro Conditions

Bifidobacteria are frequently used in probiotic food and dairy products. Bifidobacterium bifidum S17 is a promising probiotic candidate strain that displays strong adhesion to intestinal epithelial cells and elicits potent anti-inflammatory capacity both in vitro and in murine models of colitis. The recently sequenced genome of B. bifidum S17 has a size of about 2.2 Mb and encodes 1,782 predicted protein-coding genes. In the present study, a comprehensive proteomic profiling was carried out to identify and characterize proteins expressed by B. bifidum S17. A total of 1148 proteins entries were identified by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), representing 64.4% of the predicted proteome. 719 proteins could be assigned to functional categories according to cluster of orthologous groups of proteins (COGs). The COG distribution of the detected proteins highly correlates with that of the complete predicted proteome suggesting a good coverage and representation of the genomic content of B. bifidum S17 by the proteome. COGs that were highly present in the proteome of B. bifidum S17 were Translation, Amino Acid Transport and Metabolism, and Carbohydrate Transport and Metabolism. Complete sets of enzymes for both the bifidus shunt and the Embden-Meyerh of pathway were identified. Further bioinformatic analysis yielded 28 proteins with a predicted extracellular localization including 14 proteins with an LPxTG-motif for cell wall anchoring and two proteins (elongation factor Tu and enolase) with a potential moonlighting function in adhesion. Amongst the predicted extracellular proteins were five of six pilin proteins encoded in the B. bifidum S17 genome as well as several other proteins with a potential role in interaction with host structures. The presented results are the first compilation of a proteomic reference profile for a B. bifidum strain and will facilitate analysis of the molecular mechanisms of physiology, host-interactions and beneficial effects of a potential probiotic strain.

Biodistribution of a Promising Probiotic, Bifidobacterium longum subsp. longum Strain BBMN68, in the Rat Gut.

Bifidobacterium longum subsp. longum BBMN68, isolated from centenarians in Guangxi, China, has been proved to be a promising probiotic strain for its health benefits. In this study, the biodistribution of this strain in the rat gut was first investigated using the quantitative realtime PCR assay and propidium monoazide. Strain-specific primers were originally designed based on the BBMN68 genome sequence. Healthy rats were orally inoculated with either a single dose of BBMN68 (10(10) colony-forming units/kg), or with one dose per day for 7 days and bacterial concentrations were analyzed in detail from the intestinal contents and feces of four different gut locations, including stomach, small intestine, colon, and rectum. Results indicated that strain BBMN68 could overcome the rigors of passage through the upper gastrointestinal tract and transiently accumulate in the colon, even though survival in the stomach and small intestine was not high. A good level of BBMN8 could stay in vivo for 72 h following a 7-day oral administration, and a daily administration is suggested for a considerable and continuous population of BBMN68 to be maintained in the host intestine.

Immunity, gut microbiota and infection

Recurrent infections are very common in children and a major challenge for pediatricians. They affect the children’s quality of life, cause absences from school and lost parental working days, and repeated medical examinations, hospital admissions as well as antibiotic therapies lead to high costs for society. Given their prevalence and clinical importance, various prevention strategies have been developed. Some of these strategies have considered that innate and adaptive immunity are strictly related with gut microbiota and interact in the modulation of host’s reactivity to infections. Variations in gut microbiota related to age, nutrition or underlying disease may influence immune system defenses against viruses and bacteria. Furthermore, disturbed gut colonization patterns are proposed to be associated with the development of allergic disease. This explains why probiotics represent an important option in the prophylaxis and the management of recurrent infectious diseases as well as allergic diseases. However, the incomplete understanding of what constitutes a healthy gut microbiota that promotes tolerance, remains a challenge. Further understanding of gut microbial functions may pave the way for more effective prevention and treatment strategies. Another approach used for prevention of recurrent infections is represented by the administration of immunostimulants: i.e. molecules of bacterial or synthetic origin that interact with immunological mechanisms in vitro and in vivo. Pidotimod (3-L-pyroglutamil-L-thiaziolidine-4-carboxylic acid) is a synthetic dipeptide which stimulates the phagocytic activity of polymorphonuclear leukocytes, enhances the killing activity of human alveolar macrophages, increases the cytotoxic activity of natural killer cells, and stimulates cytokine production. It also influences the maturation and activity of dendritic cells by increasing the expression of the key surface markers that help to trigger T cell activation and increased IL-12 production. The majority of studies have shown that the number of infections decreases after pidotimod treatment, but they are affected by some methodological weaknesses. Further studies are urgently needed to confirm the pediatric population that should have the greatest benefit with the administration of immunostimulants. More studies are needed to identify the most promising probiotic strains and study populations, and to evaluate the mechanisms behind the possible effects of probiotics on OM.

Draft Genome Sequence of Enterococcus faecalis MB5259

In this study, we present a draft genome sequence of Enterococcus faecalis MB5259, a promising probiotic strain. The identified differences and common features between this strain and reference strains will assist in better understanding the mechanism of antibacterial action and in developing novel probiotics.

Potential Probiotic Characterization of Lactobacillus plantarum Strains Isolated from Inner Mongolia “Hurood” Cheese

Total 121 lactic acid bacteria were isolated from homemade Inner Mongolia extra hard Hurood cheese. Seven of these strains, identified as Lactobacillus plantarum, were studied for probiotic characteristics. All seven strains survived at pH 3.0 for 3 h, or in the presence of oxgall at 0.3% or 0.6% for 4 h, but their viabilities were affected to different extents at pH 2.0 for 3 h. Strains C37 and C51 showed better adherence to Caco-2 cells, and higher hydrophobicity. The seven L. plantarum strains were different in in vitro free radical scavenging activities and cholesterolreducing ability. In vivo evaluation of the influence of L. plantarum C37 on the intestinal flora in a mouse model showed strain C37 could increase the viable counts of lactobacilli in feces of mice and decrease the viable counts of enterococci. When L. plantarum C37 was used to prepare probiotic Hurood cheese, it was able to maintain high viable counts (>7.8 log CFU/g) during the whole storage period, but the composition of the cheese was not changed. These results indicate that L. plantarum C37 could be considered as a promising probiotic strain.

Structure of the cell wall polysaccharides of probiotic bifidobacteria Bifidobacteriumbifidum BIM B-465

The composition and structure of cell wall polysaccharides of a biotechnologically promising probiotic strain of bifidobacteria Bifidobacterium bifidum BIM B-465 were established by monosaccharide and methylation analyses along with 2D 1H– 1H homonuclear and 1H– 13C heteronuclear correlation NMR spectroscopy. The major polysaccharide represents a branched glucogalactan consisting of heptasaccharide repeating units having the following structure: [Display omitted] The second isolated polysaccharide is a branched glucan with the main chain of (1→6)-linked α- d-glucopyranose residues, ∼60% of which are 2-substituted with a single α- d-glucopyranosyl group. This polysaccharide is a characteristic of various microorganisms, including some lactobacteria studied earlier.