A total of 22 Lactobacillus strains, which were isolated from infant feces were evaluated for their probiotic potential along with resistance to low pH and bile salts. Eight isolates (L. reuteri 3M02 and 3M03, L. gasseri 4M13, 4R22, 5R01, 5R02, and 5R13, and L. rhamnosus 4B15) with high tolerance to acid and bile salts, and ability to adhere to the intestine were screened from 22 strains. Further, functional properties of 8 Lactobacillus strains, such as anti-oxidation, inhibition of α-glucosidase activity, cholesterol-lowering, and anti-inflammation were evaluated. The properties were strain-specific. Particularly, two strains of L. rhamnosus, 4B15 (4B15) and L. gasseri 4M13 (4M13) showed considerably higher anti-oxidation, inhibition of α-glucosidase activity, and cholesterol-lowering, and greater inhibition of nitric oxide production than other strains. Moreover, the two selected strains substantially inhibited the release of inflammatory mediators such as TNF-α, IL-6, IL-1β, and IL-10 stimulated the treatment of RAW 264.7 macrophages with LPS. In addition, whole genome sequencing and comparative genomic analysis of 4B15 and 4M13 indicated them as novel genomic strains. These results suggested that 4B15 and 4M13 showed the highest probiotic potential and have an impact on immune health by modulating pro-inflammatory cytokines.

Although the immune response of Caenorhabditis elegans to microbial infections is well established, very little is known about the effects of health-promoting probiotic bacteria on evolutionarily conserved C. elegans host responses. We found that the probiotic Gram-positive bacterium Lactobacillus acidophilus NCFM is not harmful to C. elegans and that L. acidophilus NCFM is unable to colonize the C. elegans intestine. Conditioning with L. acidophilus NCFM significantly decreased the burden of a subsequent Enterococcus faecalis infection in the nematode intestine and prolonged the survival of nematodes exposed to pathogenic strains of E. faecalis and Staphylococcus aureus , including multidrug-resistant (MDR) isolates. Preexposure of nematodes to Bacillus subtilis did not provide any beneficial effects. Importantly, L. acidophilus NCFM activates key immune signaling pathways involved in C. elegans defenses against Gram-positive bacteria, including the p38 mitogen-activated protein kinase pathway (via TIR-1 and PMK-1) and the β-catenin signaling pathway (via BAR-1). Interestingly, conditioning with L. acidophilus NCFM had a minimal effect on Gram-negative infection with Pseudomonas aeruginosa or Salmonella enterica serovar Typhimurium and had no or a negative effect on defense genes associated with Gram-negative pathogens or general stress. In conclusion, we describe a new system for the study of probiotic immune agents and our findings demonstrate that probiotic conditioning with L. acidophilus NCFM modulates specific C. elegans immunity traits.

The present review has mainly focused on the specific parameters including aging (aging days, temperature, relative humidity, and air flow), eating quality (flavor, tenderness and juiciness), microbiological quality and economic (shrinkage, retail yields and cost) involved beef dry aging process. Dry aging is the process where beef carcasses or primal cuts are hanged and aged for 28 to 55 d under controlling environment conditions in a refrigerated room with 0° to 4 °C and with relative humidity of 75 to 80 %. However there are various opinions on dry aging procedures and purveyors of such products are passionate about their programs. Recently, there has been an increased interest in dry aging process by a wider array of purveyors and retailers in the many countries. Dry aging process is very costly because of high aging shrinkage (6 to15 %), trims loss (3 to 24 %), risk of contamination and the requirement of highest grades meat with. The packaging in highly moisture-permeable bag may positively impact on safety, quality and shelf stability of dry aged beef. The key effect of dry aging is the concentration of the flavor that can only be described as “dry-aged beef”. But the contribution of flavor compounds of proteolysis and lipolysis to the cooked dry aged beef flavor is not fully known. Also there are limited scientific studies of aging parameters on the quality and palatability of dry aged beef.

Osteoporosis is a systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue, with a consequent increase in bone fragility and fracture susceptibility. In an aged society with increased life expectancy, the incidence rate of osteoporosis is also rapidly increasing. Inadequate nutrition may negatively influence bone metabolism. Recently, many studies have investigated the functionality of milk-derived exosomes, which play important roles in cell-to-cell communication. However, there are few reports of how milk-derived exosomes influence osteoblast proliferation and differentiation. Here, we determined whether bovine colostrum-derived exosomes promote anti-osteoporosis in vitro and in vivo. Tartrate-resistant acid phosphatase-stained cells were significantly inhibited in Raw264.7 cells treated with exosomes, indicating reduced osteoclast differentiation. We induced osteoporosis in mice using glucocorticoid pellets after orally administering exosomes for 2 mo. Interestingly, the bone mineral density of exosome-fed mouse groups was significantly improved compared with the glucocorticoid-induced osteoporosis group without exosome treatment. In addition, Lactobacillus were decreased in the gut microbiota community of osteoporosis-induced mice, but the gut microbiota community composition was effectively restored by exosome intake. Taken together, we propose that exosomes isolated from bovine colostrum could be a potential candidate for osteoporosis prevention, bone remodeling improvement, and inhibition of bone resorption. To our knowledge, this is the first time that a protective effect of milk exosomes against osteoporosis has been demonstrated in vivo. Our results strongly suggest that bovine colostrum exosomes might be used as a prophylaxis to prevent the onset of osteoporosis. Indeed, our results offer promising alternative strategies in the nutritional management of age-related bone complications.

Staphylococcus aureus, the leading cause of hospital-acquired infections in the United States, is also pathogenic to the model nematode Caenorhabditis elegans. The C. elegans-S. aureus infection model was previously carried out on solid agar plates where the bacteriovorous C. elegans feeds on a lawn of S. aureus. However, agar-based assays are not amenable to large scale screens for antibacterial compounds. We have developed a high throughput liquid screening assay that uses robotic instrumentation to dispense a precise amount of methicillin resistant S. aureus (MRSA) and worms in 384-well assay plates, followed by automated microscopy and image analysis. In validation of the liquid assay, an MRSA cell wall defective mutant, MW2ΔtarO, which is attenuated for killing in the agar-based assay, was found to be less virulent in the liquid assay. This robust assay with a Z’-factor consistently greater than 0.5 was utilized to screen the Biomol 4 compound library consisting of 640 small molecules with well characterized bioactivities. As proof of principle, 27 of the 30 clinically used antibiotics present in the library conferred increased C. elegans survival and were identified as hits in the screen. Surprisingly, the antihelminthic drug closantel was also identified as a hit in the screen. In further studies, we confirmed the anti-staphylococcal activity of closantel against vancomycin-resistant S. aureus isolates and other Gram-positive bacteria. The liquid C. elegans – S. aureus assay described here allows screening for anti-staphylococcal compounds that are not toxic to the host.

Here, we examined the functionality of Lactobacillus fermentum strain JDFM216, a newly isolated probiotic bacterium, using a Caenorhabditis elegans model. We determined bacterial colonization in the intestinal tract of C. elegans by plate counting and transmission electron microscopy and examined the survival of C. elegans using a solid killing assay. In addition, we employed DNA microarray analysis, quantitative real time-polymerase chain reaction, and immunoblotting assays to explore health-promoting pathways induced by probiotic bacteria in C. elegans. Initially, we found that the probiotic bacterium L. fermentum strain JDFM216 was not harmful to the C. elegans host. Conditioning with JDFM216 led to its colonization in the nematode intestine and enhanced resistance in nematodes exposed to food-borne pathogens, including Staphylococcus aureus and Escherichia coli O157:H7. Interestingly, this probiotic strain significantly prolonged the life span of C. elegans. Whole-transcriptome analysis and transgenic worm assays revealed that the health-promoting effects of JDFM216 were mediated by a nuclear hormone receptor (NHR) family and PMK-1 signaling. Taken together, we described a new C. elegans-based system to screen novel probiotic activity and demonstrated that preconditioning with the probiotic L. fermentum strain JDFM216 may positively stimulate the longevity of the C. elegans host via specific pathway.