One strain of Lactobacillus salivarius, two strains of Lactobacillus reuteri and Lactobacillus amylovorus, and two strains of Bifidobacterium thermacidophilum with antagonistic effect against Clostridium perfringens were isolated from porcine gastrointestinal tract. Isolates were assayed for their ability to survive in synthetic gastric juice at pH 2.5 and were examined for their ability to grow on agar plate containing porcine bile extract. There was a large variation in the survival of the isolates in gastric juice and growth in the medium containing 0.3% (w/v) bile. L. salivarius G11 and L. amylovorus S6 adhered to the HT-29 epithelial cell line. Cell-free supernatant of L. amylovorus S6 showed higher antagonistic activity as effective as the antibiotics such as neomycin, chlortetracycline, and oxytetracycline against bacterial pathogens including C. perfringens, Salmonella typhimurium, Staphylococcus aureus, Vibrio cholerae, Edwardsiella tarda, and Aeromonas salmonicida subsp. salmonicida.

This study examined the role of the periplasmic oxidative defense proteins, copper, zinc superoxide dismutase (SodC), and thiol peroxidase (Tpx), from the Shiga toxin-producing Escherichia coli O157:H7 (STEC) in the formation of biofilms. Proteomic analyses have shown significantly higher expression levels of both periplasmic antioxidant systems (SodC and Tpx) in STEC cells grown under biofilm conditions than under planktonic conditions. An analysis of their growth phase-dependent gene expression indicated that a high level of the sodC expression occurred during the stationary phase and that the expression of the tpx gene was strongly induced only during the exponential growth phase. Exogenous hydrogen peroxide reduced the aerobic growth of the STEC sodC and tpx mutants by more than that of their parental strain. The two mutants also displayed significant reductions in their attachment to both biotic (HT-29 epithelial cell) and abiotic surfaces (polystyrene and polyvinyl chloride microplates) during static aerobic growth. However, the growth rates of both wild-type and mutants were similar under aerobic growth conditions. The formation of an STEC biofilm was only observed with the wild-type STEC cells in glass capillary tubes under continuous flow-culture conditions compared with the STEC sodC and tpx mutants. To the best of our knowledge, this is the first mutational study to show the contribution of sodC and tpx gene products to the formation of an E. coli O157:H7 biofilm. These results also suggest that these biofilms are physiologically heterogeneous and that oxidative stress defenses in both the exponential and stationary growth stages play important roles in the formation of STEC biofilms.

The inhibitory effects of green tea polyphenol epigallocatechin gallate (EGCG) on virulence phenotypes and gene expression regulated by quorum sensing (QS) in Escherichia coli O157:H7 were demonstrated at concentrations of 1 to 100 microg/ml, which are lower than the MIC (539 +/- 22 microg/ml). At 25 microg/ml, the growth rate was not affected, but autoinducer 2 concentration, biofilm formation, and swarm motility decreased to 13.2, 11.8, and 50%, respectively. Survival at 5 days of nematodes (Caenorhabditis elegans) that were fed the pathogen without and with EGCG were 47.1 and 76%, respectively. Real-time PCR data indicated decreased transcriptional level in many quorum sensing-regulated virulence genes at 25 microg/ml. Our results suggest that EGCG at concentrations below itsMIC has significant antipathogenic effects against E. coli O157:H7.

The use of role-assigned ionic additives with different adsorption energies and distinct electron-accepting abilities enables the construction of a multilayer solid electrolyte interphase (SEI) with a sequential structure of lithiophilic, mechanically robust, and ionpermeable layers on Li metal anodes. The uncontrollable Li dendrite formation, which is promoted by localized electric fields on the Li metal anode, is suppressed by the lithiophilic Ag-containing inner SEI and LiF + Li 3 N-enriched outer SEI with reduced overpotentials upon Li deposition.

This study was carried out to evaluate the effect of bacteriocin produced by Lactococcus sp. HY 449 against skin-inflammatory bacteria such as Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 65389, Streptococcus pyogenes ATCC 21059, and Propionibacterium acnes ATCC 6919. The spot-on-the-lawn method was used to determine the antimicrobial activity of bacteriocin against indicator strains on the human skin. The bacteriocin produced by Lactococcus sp. HY 449 inhibited the growth of S. epidermidis ATCC 12228, S. aureus ATCC 65389, Strep. pyogenes ATCC 21059, and P. acnes ATCC 6919. The treatment of crude bacteriocin caused a rapid inactivation of P. acnes ATCC 6919. The LC50 of bacteriocin on human fibroblast was ca. 50mg/ml at which the inhibition of cell proliferation was not observed. Neither any irritations nor allergic reactions by the bacteriocin were evident in a human patch test. The bacteriocin produced by Lactococcus sp. HY 449 may be a useful antimicrobial substance to control the growth of P. acnes and to prevent skin inflammation and acne.

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Lactobacillus acidophilus 30SC has been isolated from swine intestines and considered a probiotic strain for dairy products because of its ability to assimilate cholesterol and produce bacteriocins. Here, we report the complete genome sequence of Lactobacillus acidophilus 30SC (2,078,001 bp) exhibiting strong acid resistance and enhanced bile tolerance.Lactobacillus acidophilus 30SC is an intestinal isolate from swine and known to assimilate cholesterol and produce a thermostable and pH-stable bacteriocin (9). This bacteriocin may have a potential application in food systems controlling food spoilage microorganisms and food-borne pathogens (3, 9). In addition, L. acidophilus 30SC showed excellent acid resistance and enhanced bile tolerance compared to commercial probiotic strains that are presently used in dairy products (9). These properties are advantageous characteristics to a probiotic strain by providing a greater chance of survival during passage through the stomach and intestinal tract. In order to understand these unique properties on the genomic level, we attempted whole-genome sequencing.The genome of L. acidophilus 30SC was sequenced by Roche 454 GS FLX (454 GS FLX) platforms. The initial draft assembly was prepared from two separate libraries of 158,188 and 235,924 paired-end reads containing 3-kb inserts and yielded 15 scaffolds (21 contigs) by the Newbler gsAssembler 2.3 (454 Life Sciences, Branford, CT). The actual order of scaffolds was checked by a series of PCRs based on a permutation table. The genome sequence was finished by filling gaps with gapResolution (Cliff Han, unpublished data; provided by the Joint Genome Institute) and sequencing by ABI system (Applied Biosystems, CA) followed by primer walking PCR between contigs.The complete genome sequence of L. acidophilus 30SC revealed one circular chromosome of 2,078,001 bp with a GC content of 38.1%. Two circular plasmids that have not been reported were also identified: pRKC30SC1 (7,197 bp) and pRKC30SC2 (12,568 bp), with GC content values of 35.1% and 36.6%, respectively. The full annotation was performed by a RAST server (1) and NCBI Prokaryotic Genomes Automatic Annotation Pipeline (PGAAP) (http://www.ncbi.nlm.nih.gov /genomes/static/Pipeline.html). Both annotations were scrutinized with manual inspection. The chromosome has 2,138 coding sequences (CDS), 63 tRNA genes, and 12 rRNA genes. The pRKC30SC1 and pRKC30SC2 plasmids have 7 CDS and 16 CDS, respectively.The genome sequencing revealed genes known to be implicated in bile acid tolerance, such as choloylglycine hydrolase, known as bile salt hydrolase and bile acid-inducible operon protein (4, 10). As in Lactobacillus amylovorus, which has recently been sequenced (7), we found two kinds of S-layer proteins, mucus-and fibronectin-binding proteins participating in adhesion to intestinal cells (2, 6) and five genes encoding bacteriocins, such as amylovorin (5) and helveticin (11), that can inhibit the growth of pathogenic bacteria (8), suggesting its potential as a probiotic bacterium.Nucl...

Milk is known as a safe food and contains easily absorbable minerals and proteins, including whey protein, which has demonstrated antiosteoporotic effects on ovariectomized rats. This study evaluated the antiosteoporotic effect of whey protein concentrate hydrolysate (WPCH) digested with fungal protease and whey protein concentrate (WPC). Two experiments were conducted to determine (1) efficacy of WPCH and WPC and (2) dose-dependent impact of WPCH in ovariectomized rats (10 weeks old). In Experiment I, ovariectomized rats (n = 45) were allotted into three dietary treatments of 10 g/kg diet of WPC, 10 g/kg diet of WPCH, and a control diet. In Experiment II, ovariectomized rats (n = 60) were fed four different diets (0, 10, 20, and 40 g/kg of WPCH). In both experiments, sham-operated rats (n = 15) were also fed a control diet containing the same amount of amino acids and minerals as dietary treatments. After 6 weeks, dietary WPCH prevented loss of bone, physical properties, mineral density, and mineral content, and improved breaking strength of femurs, with similar effect to WPC. The bone resorption enzyme activity (tartrate resistance acid phosphatase) in tibia epiphysis decreased in response to WPCH supplementation, while bone formation enzyme activity (alkaline phosphatase) was unaffected by ovariectomy and dietary treatment. Bone properties and strength increased as the dietary WPCH level increased (10 and 20 g/kg), but there was no difference between the 20 and 40 g/kg treatment. WPCH and WPC supplementation ameliorated bone loss induced by ovariectomy in rats.