[Improvement of Nitrite Analysis Method in Food Products].

The conventional analysis method has problems with extraction efficiency, operability, and reproducibility. In this study, we attempted to solve these problems and improve the analytical method to obtain sufficient extraction efficiency and good operability and accuracy. The conventional method was able to get sufficient extraction in dried meat products, where the extraction efficiency of the conventional method was low, by increasing the concentration of sodium hydroxide solution at the time of homogenization. Suction filtration after adding the defoaming agent was added allowed for accurate volume adjustment. The turbidity of the extract caused by insufficient addition of zinc acetate solution was removed by increasing the amount of zinc acetate solution that was added. Turbidity caused by starch was removed by adding pancreatin. The RSD of the quantitative values was improved by adding sodium hydroxide solution and 80-90℃ water and immediately homogenizing. Furthermore, by changing the dilution factor of the extract solution in the colorimetric method, the inhibition of coloration by reducing substances was suppressed, and more accurate quantitative values could be obtained than with the conventional method. The recovery rate was 78.5-105% (RSD 0.7-5.8%), which was a good result. This method was considered to be a useful analytical method that can contribute to improving the inspection accuracy of nitrite ion analysis.

Effect of Lactobacillus casei strain Shirota-fermented milk on metabolic abnormalities in obese prediabetic Japanese men: a randomised, double-blind, placebo-controlled trial.

An obesity-related prediabetic state is characterised by metabolic abnormalities such as post-glucose load hyperglycaemia and dyslipidaemia and consequently increases the risk for type 2 diabetes and cardiovascular disease. This study aimed to investigate the effects of Lactobacillus casei strain Shirota (LcS) on metabolic abnormalities in obese prediabetic subjects in a randomised, double-blind, placebo-controlled trial. Herein, 100 obese subjects (body mass index ≥25), who had moderate post-load hyperglycaemia (1-hr post-load plasma glucose (PG) levels ≥180 mg/dl during the oral glucose tolerance test), consumed LcS-fermented milk or placebo milk daily for 8 weeks. The post-load PG and fasting blood markers were evaluated. Although post-load PG levels were not significantly different between the groups, 1-hr post-load PG, glycoalbumin, and HbA1c levels decreased at 8 weeks compared with the baseline levels only in the LcS group (p=0.036, p=0.002, and p=0.006, respectively). The reduction in glycoalbumin levels was statistically significantly greater in the LcS group than in the placebo group (p=0.030). Stratified analyses revealed significantly improved 1-hr post-load PG and glycoalbumin levels in the LcS group compared with the placebo group among subjects with severe glucose intolerance (2-hr post-load PG levels higher than the median at baseline; p=0.036 and p=0.034, respectively). In terms of lipidic outcomes, total, low-density lipoprotein, and non-high-density lipoprotein cholesterol levels were significantly lower in the LcS group than in the placebo group (p=0.023, p=0.022, and p=0.008, respectively). These findings suggest that LcS may favourably affect metabolic abnormalities in obese prediabetic subjects, though the effects on glycaemic control may be limited.

Daily intake of fermented milk with Lactobacillus casei strain Shirota reduces the incidence and duration of upper respiratory tract infections in healthy middle-aged office workers.

PURPOSE: Although several studies have demonstrated the efficacy of probiotics for preventing upper respiratory tract infections (URTIs) in at-risk populations, including children and the elderly, few studies have investigated the efficacy of probiotics in healthy adults living normal, everyday lives. Thus, we tried to evaluate the effects of Lactobacillus casei strain Shirota-fermented milk (LcS-FM) on the incidence of URTIs in healthy middle-aged office workers. METHODS: In a randomized controlled trial, 96 eligible male workers aged 30-49 years consumed LcS-FM containing 1.0 × 1011 viable LcS cells or control milk (CM) once daily for 12 weeks during the winter season. URTI episodes were evaluated by a physician via a questionnaire of URTI symptoms. RESULTS: The incidence of URTIs during the intervention period was significantly lower in the LcS-FM group than in the CM group (22.4 vs. 53.2 %, P = 0.002). The time-to-event analysis showed that the LcS-FM group had a significantly higher URTI-free rate than the CM group over the test period (log-rank test: χ 2 11.25, P = 0.0008). The cumulative number of URTI episodes and cumulative days with URTI symptoms per person was lower in the LcS-FM group, and the duration per episode was shorter. Inhibition of both reductions in NK cell activity in peripheral blood mononuclear cells and increases in salivary cortisol levels was observed in the LcS-FM group. CONCLUSION: The results suggest that the daily intake of fermented milk with LcS may reduce the risk of URTIs in healthy middle-aged office workers, probably through modulation of the immune system.

Fermented Milk Containing Lactobacillus casei Strain Shirota Preserves the Diversity of the Gut Microbiota and Relieves Abdominal Dysfunction in Healthy Medical Students Exposed to Academic Stress.

UNLABELLED: Stress-induced abdominal dysfunction is an attractive target for probiotics. To investigate the effects of the probiotic Lactobacillus casei strain Shirota on abdominal dysfunction, a double-blind, placebo-controlled trial was conducted with healthy medical students undertaking an authorized nationwide examination for academic advancement. For 8 weeks, until the day before the examination, 23 and 24 subjects consumed an L. casei strain Shirota-fermented milk and a placebo milk daily, respectively. In addition to assessments of abdominal symptoms, psychophysical state, and salivary stress markers, gene expression changes in peripheral blood leukocytes and composition of the gut microbiota were analyzed using DNA microarray analysis and 16S rRNA gene amplicon sequence analysis, respectively, before and after the intervention. Stress-induced increases in a visual analog scale measuring feelings of stress, the total score of abdominal dysfunction, and the number of genes with changes in expression of more than 2-fold in leukocytes were significantly suppressed in the L. casei strain Shirota group compared with those in the placebo group. A significant increase in salivary cortisol levels before the examination was observed only in the placebo group. The administration of L. casei strain Shirota, but not placebo, significantly reduced gastrointestinal symptoms. Moreover, 16S rRNA gene amplicon sequencing demonstrated that the L. casei strain Shirota group had significantly higher numbers of species, a marker of the alpha-diversity index, in their gut microbiota and a significantly lower percentage of Bacteroidaceae than the placebo group. Our findings indicate that the daily consumption of probiotics, such as L. casei strain Shirota, preserves the diversity of the gut microbiota and may relieve stress-associated responses of abdominal dysfunction in healthy subjects exposed to stressful situations. IMPORTANCE: A novel clinical trial was conducted with healthy medical students under examination stress conditions. It was demonstrated that the daily consumption of lactic acid bacteria provided health benefits to prevent the onset of stress-associated abdominal symptoms and a good change of gut microbiota in healthy medical students.

Inhibition of interferon regulatory factor 3 activation by paramyxovirus V protein.

The V protein of Sendai virus (SeV) suppresses innate immunity, resulting in enhancement of viral growth in mouse lungs and viral pathogenicity. The innate immunity restricted by the V protein is induced through activation of interferon regulatory factor 3 (IRF3). The V protein has been shown to interact with melanoma differentiation-associated gene 5 (MDA5) and to inhibit beta interferon production. In the present study, we infected MDA5-knockout mice with V-deficient SeV and found that MDA5 was largely unrelated to the innate immunity that the V protein suppresses in vivo. We therefore investigated the target of the SeV V protein. We previously reported interaction of the V protein with IRF3. Here we extended the observation and showed that the V protein appeared to inhibit translocation of IRF3 into the nucleus. We also found that the V protein inhibited IRF3 activation when induced by a constitutive active form of IRF3. The V proteins of measles virus and Newcastle disease virus inhibited IRF3 transcriptional activation, as did the V protein of SeV, while the V proteins of mumps virus and Nipah virus did not, and inhibition by these proteins correlated with interaction of each V protein with IRF3. These results indicate that IRF3 is important as an alternative target of paramyxovirus V proteins.

Conserved charged amino acids within Sendai virus C protein play multiple roles in the evasion of innate immune responses.

One of the accessory proteins of Sendai virus (SeV), C, translated from an alternate reading frame of P/V mRNA has been shown to function at multiple stages of infection in cell cultures as well as in mice. C protein has been reported to counteract signal transduction by interferon (IFN), inhibit apoptosis induced by the infection, enhance the efficiency of budding of viral particles, and regulate the polarity of viral genome-length RNA synthesis to maximize production of infectious particles. In this study, we have generated a series of SeV recombinants containing substitutions of highly conserved, charged residues within the C protein, and characterized them together with previously-reported C'/C(-), 4C(-), and F170S recombinant viruses in infected cell cultures in terms of viral replication, cytopathogenicity, and antagonizing effects on host innate immunity. Unexpectedly, the amino acid substitutions had no or minimal effect on viral growth and viral RNA synthesis. However, all the substitutions of charged amino acids resulted in the loss of a counteracting effect against the establishment of an IFN-alpha-mediated anti-viral state. Infection by the virus (Cm2') containing mutations at K77 and D80 induced significant IFN-beta production, severe cytopathic effects, and detectable amounts of viral dsRNA production. In addition to the Cm2' virus, the virus containing mutations at E114 and E115 did not inhibit the poly(I:C)-triggered translocation of cellular IRF-3 to the nucleus. These results suggest that the C protein play important roles in viral escape from induction of IFN-beta and cell death triggered by infection by means of counteracting the pathway leading to activation of IRF-3 as well as of minimizing viral dsRNA production.