Metabolic regulation of longevity and immune response in Caenorhabditis elegans by ingestion of Lacticaseibacillus rhamnosus IDCC 3201 using multi-omics analysis.

Probiotics, specifically Lacticaseibacillus rhamnosus, have garnered attention for their potential health benefits. This study focuses on evaluating the probiotics properties of candidate probiotics L. rhamnosus IDCC 3201 (3201) using the Caenorhabditis elegans surrogate animal model, a well-established in vivo system for studying host-bacteria interactions. The adhesive ability to the host's gastrointestinal tract is a crucial criterion for selecting potential probiotic bacteria. Our findings demonstrated that 3201 exhibits significantly higher adhesive capabilities compared with Escherichia coli OP50 (OP50), a standard laboratory food source for C. elegans and is comparable with the widely recognized probiotic L. rhamnosus GG (LGG). In lifespan assay, 3201 significantly increased the longevity of C. elegans compared with OP50. In addition, preconditioning with 3201 enhanced C. elegans immune response against four different foodborne pathogenic bacteria. To uncover the molecular basis of these effects, transcriptome analysis elucidated that 3201 modulates specific gene expression related to the innate immune response in C. elegans. C-type lectin-related genes and lysozyme-related genes, crucial components of the immune system, showed significant upregulation after feeding 3201 compared with OP50. These results suggested that preconditioning with 3201 may enhance the immune response against pathogens. Metabolome analysis revealed increased levels of fumaric acid and succinic acid, metabolites of the citric acid cycle, in C. elegans fed with 3201 compared with OP50. Furthermore, there was an increase in the levels of lactic acid, a well-known antimicrobial compound. This rise in lactic acid levels may have contributed to the robust defense mechanisms against pathogens. In conclusion, this study demonstrated the probiotic properties of the candidate probiotic L. rhamnosus IDCC 3201 by using multi-omics analysis.

Dietary L-Methionine modulates the gut microbiota and improves the expression of tight junctions in an in vitro model of the chicken gastrointestinal tract.

BACKGROUND: The poultry industry encounters a number of factors that affect growth performance and productivity; nutrition is essential for sustaining physiological status and protecting against stressors such as heat, density, and disease. The addition of vitamins, minerals, and amino acids to the diet can help restore productivity and support the body's defense mechanisms against stress. Methionine (Met) is indispensable for poultry's energy metabolism, physiology, performance, and feed utilization capacity. Through this study, we aimed to examine the physiological effects of methionine supplementation on poultry as well as alterations of intestinal microbiome. METHODS: We utilized the DL- and L- form of methionine on Caenorhabditis elegans and the FIMM (Fermentor for intestine microbiota model) in-vitro digesting system. A genomic-analysis of the transcriptome confirmed that methionine supplementation can modulate growth-related physiological metabolic pathways and immune responses in the host poultry. The C. elegans model was used to assess the general health benefits of a methionine supplement for the host. RESULTS: Regardless of the type or concentration of methionine, supplementation with methionine significantly increased the lifespan of C. elegans. Feed grade L-Methionine 95%, exhibited the highest lifespan performance in C. elegans. Methionine supplementation increased the expression of tight junction genes in the primary intestinal cells of both broiler and laying hens, which is directly related to immunity. Feed grade L-Methionine 95% performed similarly or even better than DL-Methionine or L-Methionine treatments with upper doses in terms of enhancing intestinal integrity. In vitro microbial cultures of healthy broilers and laying hens fed methionine revealed changes in intestinal microflora, including increased Clostridium, Bacteroides, and Oscillospira compositions. When laying hens were given feed grade L-Methionine 95% and 100%, pathogenic Campylobacter at the genus level was decreased, while commensal bacteria were increased. CONCLUSIONS: Supplementation of feed grade L-Methionine, particularly L-Methionine 95%, was more beneficial to the host poultry than supplementing other source of methionine for maintaining intestinal integrity and healthy microbiome.

Development and application of a home-based exercise program for patients with cardiovascular disease: a feasibility study.

BACKGROUND: Cardiac rehabilitation (CR) is recommended for patients with cardiovascular disease. However, the participation and completion rates for hospital-based CR are low, and home-based CR has been suggested as an alternative. This study aimed to develop a home-based CR program and assess the feasibility of the program over a 6-week period in patients with left ventricular dysfunction or a history of myocardial infarction. METHODS: This feasibility study consisted of two phases. The initial phase (Study 1) focused on developing the home-based exercise protocol. Systematic approaches to developing evidence-based home-based exercise intervention were implemented including systematic review, patient surveys, and expert consensus. Study 2 aimed to evaluate the feasibility of a 6-week home-based CR program that was based on the results of Study 1. Study 2 included two exercise education sessions and four telephone counseling sessions. During this stage of the exercise program, the participants exercised on two separate days and their experiences while performing the aerobic and resistance exercises were surveyed. Eight participants participated in Study 1 and 16 participated in Study 2. RESULTS: Participants expressed overall satisfaction with the exercise program in Study 1. Heart rate increased in response to exercise, but this did not correspond with perceived exertion. The aim of the home-based CR exercise program was for participants to achieve exercise goals (≥150 min/week of aerobic type exercises as well as at least twice weekly resistance exercise using own body weights). We aimed to increase compliance and adherence to the home-based CR program. In Study 2, 13 out of 16 participants (81.3%) completed the 6-week home-based CR program, with a participation rate of 100% in both exercise education and phone counseling sessions. Adherence to the home-based exercise protocol was 83.1% and no serious adverse events were observed. At the beginning of the study, only three out of 13 participants (23.1%) met the requirements for both aerobic and resistance exercises, but at the end of the 6-week program, 10 out of 13 participants (76.9%) fulfilled the requirements. CONCLUSION: The exercise program developed in this study was safe and feasible, and the 6-week home-based CR program was feasible for patients with cardiovascular disease without any reported adverse effects.

Molecular characterization and environmental impact of newly isolated lytic phage SLAM_phiST1N3 in the Cornellvirus genus for biocontrol of a multidrug-resistant Salmonella Typhimurium in the swine industry chain.

Salmonella Typhimurium is a highly lethal pathogenic bacterium in weaned piglets, causing significant treatment costs and economic losses in the swine industry. Additionally, due to its ability to induce zoonotic diseases, resulting in harm to humans through the transmission of the pathogen from pork, it presents a serious public health issue. Bacteriophages (phages), viruses that infect specific bacterial strains, have been proposed as an alternative to antibiotics for controlling pathogenic bacteria. In this study, we isolated SLAM_phiST1N3, a phage infecting a multidrug-resistant (MDR) S. Typhimurium wild-type strain isolated from diseased pigs. First, comparative genomics and phylogenetic analysis revealed that SLAM_phiST1N3 belongs to the Cornellvirus genus. Moreover, utilizing a novel classification approach introduced in this study, SLAM_phiST1N3 was classified at the species level. Host range experiments demonstrated that SLAM_phiST1N3 did not infect other pathogenic bacteria or probiotics derived from pigs or other livestock. While complete eradication of Salmonella was not achievable in the liquid inhibition assay, surprisingly, we succeeded in largely eliminating Salmonella in the FIMM analysis, a gut simulation system using weaned piglet feces. Furthermore, using the C. elegans model, we showcased the potential of SLAM_phiST1N3 to prevent S. Typhimurium infection in living organisms. In addition, it was confirmed that bacterial control could be achieved when phage was applied to Salmonella-contaminated pork. pH and temperature stability experiments demonstrated that SLAM_phiST1N3 can endure swine industry processes and digestive conditions. In conclusion, SLAM_phiST1N3 demonstrates potential environmental impact as a substance for Salmonella prevention across various aspects of the swine industry chain.

Dietary effects of melatonin on growth performance by modulation of protein bioavailability and behavior in early weaned rats and pigs.

Melatonin, which is produced from tryptophan, exerts various biological functions, including the regulation of circadian rhythm, sedative agents, and antioxidant ability. Therefore, we conducted two experiments with early-weaned rats and pigs to investigate the antioxidant and sedative effects of melatonin. In the rat experiment, a total of 42 rats (21 days old) were used, and the antioxidant capacity was determined. Next, we used 120 early-weaned piglets (21 days old) to conduct a 5-week experiment to evaluate the reductive effect of melatonin on energy-wasting movement, including roaming and fight states. Dietary melatonin supplementation significantly improved growth in both rats and pigs compared to the control groups. Additionally, rats fed a melatonin-supplemented diet showed advanced antioxidant capacity with a decrease in hepatic malondialdehyde concentration compared to rats fed a basal diet. Moreover, dietary melatonin ingestion increased resting and feeding behaviors and reduced roaming and fight behaviors during Days 8-21 compared to the control diet group. Collectively, early weaned animals given dietary melatonin supplementation showed improved growth through upregulation of hepatic antioxidant capacity and minimization of energy-wasting behavior, including roaming and fight states, after pigs' social hierarchy establishment.

Multidisciplinary integrated optimal design process for optomechanical structures.

This paper presents an integrated design process for optomechanical structures based on multidisciplinary optimization. The proposed integrated optimal design process comprises a finite element analysis by ANSYS Workbench, the MATLAB optomechanical transfer program, an optical analysis by ZEMAX, and the multidisciplinary optimization solver by Isight. In ANSYS Workbench, the deformation of optical surfaces, structures, and responses according to the design requirements is calculated in one project. Then, Zernike polynomial coefficients are calculated from surface deformation data of optical surfaces through a MATLAB optomechanical transfer program. In ZEMAX, the Zernike polynomial coefficients are imported into optical surface models of an optical system; then, optical performance parameters, such as the wavefront error, optical aberration, MTF, and OPD, are calculated. In the Isight environment, automatic iterative computations are performed between these three programs and, as a result, the design dimensions of optomechanical structures are determined, satisfying the design requirements and improving the performance of an optical system. By using this integrated optimal design process, the optimal design and analysis for a complete optomechanical structure, as well as individual structure parts, can be performed successfully. In this paper, the optimal design problem for three parts of a Cassegrain telescope, which consists of a primary mirror with an outer diameter of 156 mm and a secondary mirror with an outer diameter of 46 mm, was taken as an example. By using optimal parts, the image wavefront error of the Cassegrain telescope was decreased from 29.9 to 16.1 nm.

Lactobacillus rhamnosus JY02 Ameliorates Sarcopenia by Anti-Atrophic Effects in a Dexamethasone-Induced Cellular and Murine Model.

Sarcopenia is defined as loss of muscle mass and strength due to aging. Recent studies show that sarcopenia may improve via the gut-muscle axis, suggesting that gut health may affect muscle phenotypes. In this study, we aimed to investigate the ability of Lactobacillus rhamnosus JY02 as a probiotic strain isolated from kimchi to alleviate sarcopenia. L. rhamnosus JY02-conditioned medium (CM) reduced dexamethasone (DEX)-induced myotube diameter atrophy and expression of muscle degradation markers (MuRF1 and atrogin-1) in C2C12 cells. The amelioration of sarcopenia was investigated by measuring body composition (lean mass), hand grip strength, myofibril size (using histological analysis), and mRNA and protein expression of muscle-related factors in a DEX-induced mouse model. The results of these analyses showed that L. rhamnosus JY02 supplementation promoted the production of muscle-enhancement markers (MHC Iß, MHC IIα, and Myo-D) and reduced both the production of muscle degradation markers and the symptoms of muscle atrophy (loss of lean mass and muscle strength). We also found decreased levels of pro-inflammatory cytokines (IL-6, IFN- γ) and increased levels of anti-inflammatory cytokines (IL-10) in the serum of DEX+JY02-administered mice compared to those in DEX-treated mice. Overall, these results suggest that L. rhamnosus JY02 is a potent probiotic supplement that prevents sarcopenia by suppressing muscle atrophy.

Antagonistically Functionalized Diatom Biosilica for Bio-Triboelectric Generators.

Although biomaterial-based triboelectric nanogenerators (Bio-TENGs) for use in wearable electronics and implantable sensors have been developed, power generation is not suitable for satisfying the basic requirements for practical applications. Here, to greatly enhance output performances of Bio-TENG devices, an antagonistic approach of diatom frustules (DFs) with amine and fluorine chemical functionalizations is reported. The DFs are treated with piranha solution to increase the density of hydroxyl groups and tribo-positive and tribo-negative composite films are designed with antagonistically functionalized DFs. The tribo-positive composites having electron donating functionality consist of aminated DFs and cellulose nanocrystals (CNCs), while the tribo-negative composite is composed of fluorinated DFs and polydimethylsiloxane (PDMS). An antagonistically and chemically functionalized TENG (ACF TENG) with an efficient contact area of 9.6 cm2 under a force of 8 N and a frequency of 5 Hz exhibits an output voltage of 248 V, a short-circuit current of 16.4 µA, and a power density of 2.01 W m-2 , which is 16.6 times higher than a reference (CNC:PDMS) TENG. This study shows a simple antagonistic approach for chemical functionalization as an efficient method to manipulate the tribo-polarity of bio-additives for enhancing power generation of Bio-TENGs.

Diatom Bio-Silica and Cellulose Nanofibril for Bio-Triboelectric Nanogenerators and Self-Powered Breath Monitoring Masks.

The application of biodegradable and biocompatible materials to triboelectric nanogenerators (TENGs) for harvesting energy from motions of the human body has been attracting significant research interest. Herein, we report diatom bio-silica as a biomaterial additive to enhance the output performance of cellulose nanofibril (CNF)-based TENGs. Diatom frustules (DFs), which are tribopositive bio-silica having hierarchically porous three-dimensional structures and high surface area, have hydrogen bonds with CNFs, resulting in enhanced electron-donating capability and a more roughened surface of the DF-CNF composite film. Hence, DFs were applied to form a tribopositive composite film with CNFs. The DF-CNF biocomposite film is mechanically strong, electron-rich, low-cost, and frictionally rough. The DF-CNF TENG showed an output voltage of 388 V and time-averaged power of 85.5 mW/m2 in the contact-separation mode with an efficient contact area of 4.9 cm2, and the generated power was sufficient for instantaneous illumination of 102 light-emitting diodes. In addition, a cytotoxicity study and biocompatibility tests on rabbit skin suggested that the DF-CNF composite was biologically safe. Moreover, a practical application of the DF-CNF TENG was examined with a self-powered smart mask for human breathing monitoring. This study not only suggests high output performance of biomaterial-based TENGs but also presents the diverse advantages of the DFs in human body-related applications such as self-powered health monitoring masks, skin-attachable power generators, and tactile feedback systems.

Effect of temperature on single- and mixed-strain fermentation of ruminant feeds.

Use of raw feedstuffs for livestock is limited by low digestibility. Recently, fermentation of feedstuffs has been highlighted as a new way to improve nutrient absorption through the production of organic acids using inoculated microorganisms, which can also play a probiotic role. However, standard procedures for feedstuff fermentation have not been clearly defined because the process is influenced by climatic variation, and an analytical standard for fermented feedstuffs is lacking. This study aimed to evaluate the microbiological and biochemical changes of feedstuffs during fermentation at temperatures corresponding to different seasons (10°C, 20°C, 30°C, and 40°C). We also investigated the effects of yeast, lactic acid bacteria (LAB), and Bacillus spp. on fermentation and determined the results of their interactions during fermentation. The viable cells were observed within 8 days in single-strain fermentation. However, when feedstuffs were inoculated with a culture of mixed strains, LAB were predominant at low temperatures (10°C and 20°C), while Bacillus spp. was predominant at high temperatures (30°C and 40°C). A significant drop in pH from 6.5 to 4.3 was observed when LAB was the dominant strain in the culture, which correlated with the concentrations of lactic acid. Slight ethanol production was detected above 20°C regardless of the incubation temperature, suggesting active metabolism of yeast, despite this organism making up a marginal portion of the microbes in the mixed culture. These results suggested that fermentation temperature significantly affects microbiological profiles and biochemical parameters, such as pH and the lactic acid concentration, of fermented feedstuffs. Our data provide valuable information for the determination of industrial standards for fermented feedstuffs.

Evaluation of synbiotics as gut health improvement agents against Shiga toxin-producing Escherichia coli isolated from the pig.

Colibacillosis is one of the major health problems in young piglets resulting in poor health and death caused by Escherichia coli producing F18 pili and Shiga toxin 2e. It is pivotal to reduce colibacillosis in weaned piglets to enhance production performance. In this study, we evaluated synbiotics as the gut health improvement agents in the mouse model challenged with Shiga toxin-producing E. coli (STEC) isolated from piglets. Prebiotic lactulose was formulated with each 5.0 × 106 CFU/mL of Pediococcus acidilactici GB-U15, Lactobacillus plantarum GB-U17, and Lactobacillus plantarum GB 1-3 to produce 3 combinations of synbiotics. A total of 40 three weeks old BALB/c mice were randomly assigned to 4 groups (n = 10): a control group and 3 synbiotics treated groups. Each treatment groups were daily administrated with 5.0 × 106 CFU/mL of one synbiotics for the first week, and every 3 days during the second week. All the mice were challenged with 8.0 × 108 CFU/mL of STEC 5 days after animals began to receive synbiotics. Mice treated with synbiotics based on Pediococcus acidilactici GB-U15 and Lactobacillus plantarum GB-U17 significantly improved daily weight gain compared to mice in other groups. While mice treated with GB-U15 showed better fecal index, no significant differences were observed among groups. Gross lesion and histopathological evaluations showed that mice treated with GB-U15 moderately improved recovery from STEC infection. In conclusion, our results suggest that the synbiotics formulated with lactulose and Pediococcus acidilactici GB-U15 have potential benefits to prevent and improve colibacillosis in weaned piglets.

Comparative global metabolite profiling of xylose-fermenting Saccharomyces cerevisiae SR8 and Scheffersomyces stipitis.

Bioconversion of lignocellulosic biomass into ethanol requires efficient xylose fermentation. Previously, we developed an engineered Saccharomyces cerevisiae strain, named SR8, through rational and inverse metabolic engineering strategies, thereby improving its xylose fermentation and ethanol production. However, its fermentation characteristics have not yet been fully evaluated. In this study, we investigated the xylose fermentation and metabolic profiles for ethanol production in the SR8 strain compared with native Scheffersomyces stipitis. The SR8 strain showed a higher maximum ethanol titer and xylose consumption rate when cultured with a high concentration of xylose, mixed sugars, and under anaerobic conditions than Sch. stipitis. However, its ethanol productivity was less on 40 g/L xylose as the sole carbon source, mainly due to the formation of xylitol and glycerol. Global metabolite profiling indicated different intracellular production rates of xylulose and glycerol-3-phosphate in the two strains. In addition, compared with Sch. stipitis, SR8 had increased abundances of metabolites from sugar metabolism and decreased abundances of metabolites from energy metabolism and free fatty acids. These results provide insights into how to control and balance redox cofactors for the production of fuels and chemicals from xylose by the engineered S. cerevisiae.

Simple Evaluation of Listeria monocytogenes Pathogenesis Using Caenorhabditis elegans Animal Model.

Listeria monocytogenes is a major cause of serious foodborne illness in the dairy foods. Although Caenorhabditis elegans model is well established as a virulence model of pathogenic bacteria, its application on L. monocytogenes is critically unclear. The objective of this study was to carry out an evaluation of L. monocytogenes toxicity using C. elegans nematode as a simple host model. We found that C. elegans nematodes have high susceptibility to L. monocytogenes infection, as a consequence of accumulation of bacteria in the worms' intestine. However, L. innocua, which is known to be non-toxic, is not accumulate in the intestine of worms and is not toxic similarly to Escherichia coli OP50 known as the normal feed source of C. elegans. Importantly, immune-associated genes of C. elegans were intensely upregulated more than 3.0-fold when they exposed to L. monocytogenes. In conclusion, we established that C. elegans is an effective model for studying the toxicity of L. monocytogenes and we anticipate that this system will result in the discovery of many potential anti-listeria agents for dairy foods.

Effects of short-term fasting on in vivo rumen microbiota and in vitro rumen fermentation characteristics.

OBJECTIVE: Fasting may lead to changes in the microbiota and activity in the rumen. In the present study, the effects of fasting on rumen microbiota and the impact of fasting on in vitro rumen fermentation were evaluated using molecular culture-independent methods. METHODS: Three ruminally cannulated Holstein steers were fed rice straw and concentrates. The ruminal fluids were obtained from the same steers 2 h after the morning feeding (control) and 24 h after fasting (fasting). The ruminal fluid was filtrated through four layers of muslin, collected for a culture-independent microbial analysis, and used to determine the in vitro rumen fermentation characteristics. Total DNA was extracted from both control and fasting ruminal fluids. The rumen microbiota was assessed using denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction. Microbial activity was evaluated in control and fasting steers at various intervals using in vitro batch culture with rice straw and concentrate at a ratio of 60:40. RESULTS: Fasting for 24 h slightly affected the microbiota structure in the rumen as determined by DGGE. Additionally, several microorganisms, including Anaerovibrio lipolytica, Eubacterium ruminantium, Prevotella albensis, Prevotella ruminicola, and Ruminobacter amylophilus, decreased in number after fasting. In addition, using the ruminal fluid as the inoculum after 24 h of fasting, the fermentation characteristics differed from those obtained using non-fasted ruminal fluid. Compared with the control, the fasting showed higher total gas production, ammonia, and microbial protein production (p<0.05). No significant differences, however, was observed in pH and dry matter digestibility. CONCLUSION: When in vitro techniques are used to evaluate feed, the use of the ruminal fluid from fasted animals should be used with caution.

Supplementing Rhodobacter sphaeroides in the diet of lactating Holstein cows may naturally produce coenzyme Q10-enriched milk.

OBJECTIVE: To examine the effects of Rhodobacter sphaeroides (R. sphaeroides) supplementation as a direct-fed microbial (DFM) on rumen fermentation in dairy cows and on coenzyme Q10 (CoQ10) transition into milk, an in vitro rumen simulation batch culture and an in vivo dairy cow experiment were conducted. METHODS: The characteristics of in vitro ruminal fermentation were investigated using rumen fluids from six cannulated Holstein dairy cows at 2 h post-afternoon feeding. A control treatment was included in the experiments based on a typified total mixed ration (TMR) for lactating dairy cows, which was identical to the one used in the in vivo study, plus R. sphaeroides at 0.1%, 0.3%, and 0.5% TMR dry matter. The in vivo study employed six ruminally cannulated lactating Holstein cows randomly allotted to either the control TMR (C-TMR) treatment or to a diet supplemented with a 0.5% R. sphaeroides culture (S-TMR, dry matter basis) ad libitum. The presence of R. sphaeroides was verified using denaturing gradient gel electrophoresis (DGGE) applied to the bacterial samples obtained from the in vivo study. The concentration of CoQ10 in milk and in the supernatant from the in vitro study was determined using high performance liquid chromatography. RESULTS: The results of the in vitro batch culture and DGGE showed that the concentration of CoQ10 significantly increased after 2 h of R. sphaeroides supplementation above 0.1%. When supplemented to the diet of lactating cows at the level of 0.5%, R. sphaeroides did not present any adverse effect on dry matter intake and milk yield. However, the concentration of CoQ10 in milk dramatically increased, with treated cows producing 70.9% more CoQ10 than control cows. CONCLUSION: The CoQ10 concentration in milk increased via the use of a novel DFM, and R. sphaeroides might be used for producing value-added milk and dairy products in the future.

Electrochemical Synthesis of Ammonia from Water and Nitrogen: A Lithium-Mediated Approach Using Lithium-Ion Conducting Glass Ceramics.

Lithium-mediated reduction of dinitrogen is a promising method to evade electron-stealing hydrogen evolution, a critical challenge which limits faradaic efficiency (FE) and thus hinders the success of traditional protic-solvent-based ammonia electro-synthesis. A viable implementation of the lithium-mediated pathway using lithium-ion conducting glass ceramics involves i) lithium deposition, ii) nitridation, and iii) ammonia formation. Ammonia was successfully synthesized from molecular nitrogen and water, yielding a maximum FE of 52.3 %. With an ammonia synthesis rate comparable to previously reported approaches, the fairly high FE demonstrates the possibility of using this nitrogen fixation strategy as a substitute for firmly established, yet exceedingly complicated and expensive technology, and in so doing represents a next-generation energy storage system.

Erratum to: Genome Characteristics of Lactobacillus fermentum Strain JDFM216 for Application as Probiotic Bacteria.

This erratum is being published to correct the 1st author's name of above manuscript by Jang et al. that was published in Journal of Microbiology and Biotechnology (2017, 27: 1266-1271). The 1st author name(Sung Yong Jang) should appear as 'Sung Yong Chang'.

Metabolic networks for nitrogen utilization in Prevotella ruminicola 23.

Nitrogen metabolism in gut systems remains poorly studied in spite of its importance for microbial growth and its implications for the metabolism of the host. Prevotella spp. are the most predominant bacteria detected in the rumen, but their presence has also been related to health and disease states in the human gut and oral cavity. To explore the metabolic networks for nitrogen assimilation in this bacterium, changes in gene expression profiles in response to variations in the available nitrogen source and to different concentrations of ammonium were analyzed by microarray and reverse transcription quantitative PCR, and linked with function by further proteomic analysis. The observed patterns of transcript abundances for genes involved in ammonium assimilation differed from the classical "enteric paradigm" for nitrogen utilization. Expression of genes encoding high substrate affinity nitrogen assimilation enzymes (GS-GOGAT system) was similar in growth-limiting and non-limiting nitrogen concentrations in P. ruminicola 23, whereas E. coli and Salmonella spp. responses to excess nitrogen involve only low substrate affinity enzymes. This versatile behavior might be a key feature for ecological success in habitats such as the rumen and human colon where nitrogen is rarely limiting for growth, and might be linked to previously reported Prevotella spp. population imbalances relative to other bacterial species in gut systems.

Genome Characteristics of Lactobacillus fermentum Strain JDFM216 for Application as Probiotic Bacteria.

Lactobacillus fermentum strain JDFM216, isolated from a Korean infant feces sample, possesses the ability to enhance the longevity and immune response of a Caenorhabditis elegans host. To explore the characteristics of strain JDFM216 at the genetic level, we performed whole-genome sequencing using the PacBio system. The circular draft genome has a total length of 2,076,427 bp and a total of 2,682 encoding sequences were identified. Five phylogenetically featured genes possibly related to the longevity and immune response of the host were identified in L. fermentum strain JDFM216. These genes encode UDP-N-acetylglucosamine 1-carboxyvinyltransferase (E.C. 2.5.1.7), ErfK/YbiS/YcfS/YnhG family protein, site-specific recombinase XerD, homocysteine S-methyltransferase (E.C. 2.1.1.10), and aspartate-ammonia ligase (E.C. 6.3.1.1), which are involved in peptidoglycan synthesis and amino acid metabolism in the gut environment. Our findings on the genetic background of L. fermentum strain JDFM216 and its potential candidate genes for host longevity and immune response provide new insight for the application of this strain in the food industry as newly isolated functional probiotic.

Bacillus licheniformis isolated from Korean traditional food sources enhances the resistance of Caenorhabditis elegans to infection by Staphylococcus aureus.

We investigated whether Bacillus spp., newly isolated from Korean traditional food resources, influence the resistance of hosts to foodborne pathogens, by using Caenorhabditis elegans as a surrogate host model. Initially, we selected 20 Bacillus spp. that possess antimicrobial activity against various foodborne pathogens, including Staphylococcus aureus. Among the selected strains, six strains of Bacillus spp. used in preconditioning significantly prolonged the survival of nematodes exposed to S. aureus. Based on 16S rRNA gene sequencing, all six strains were identified as B. licheniformis. Our findings suggest that preconditioning with B. licheniformis may modulate the host defense response against S. aureus.