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Kyoto, Japan

Hayashi M.,Gifu University | Kubota-Hayashi S.,Gifu University | Natori T.,Gifu University | Mizuno T.,Gifu University | And 7 more authors.
International Journal of Food Microbiology | Year: 2013

A Food Pathogen Enrichment (FPE) broth, which supports the growth of Campylobacter without lysed blood and CO2, was developed. The FPE broth supports the growth of Campylobacter to the same degree as Bolton and Preston broths. Using the FPE broth, we developed a novel rapid protocol to detect small numbers of Campylobacter in 25g of food. The sensitivity of FPE enrichment and PCR to detect Campylobacter spp. from spiked chicken meat was determined. The detection sensitivities for non-stressed C. jejuni and C. coli from fresh meat ranged from 5.8 to 1.1×101CFU per 25g of chicken meat, and those for freeze-stressed C. jejuni and C. coli from frozen meat ranged from 9.9×101 to 2.0×102CFU. The FPE broth enrichment culture (24h) of chicken meat, followed by PCR, resulted in a significantly higher detection score (80% positive) than conventional Bolton enrichment and subsequent colony isolation using mCCDA agar plates (18% positive). Differences between our new protocol and the Bolton enrichment method were due to the overgrowth of many resistant bacteria, especially extended-spectrum beta-lactamase-producing bacteria in the Bolton enrichment broth. © 2013. Source

Tanaka M.,Kyoto Seibo College | Tanaka C.,J. F. Oberlin University | Kitagawa K.,Chukyo University
Japanese Journal of Physical Fitness and Sports Medicine | Year: 2015

This study examined the physiological response to different water depths in recreational synchronized swimming. Nine middle-aged, female, recreational swimmers carried out the same team free routines in deep water (deep-water synchronized swimming: DWS) and shallow water (shallow-water synchronized swimming: SWS). Heart rate (HR) was measured continuously during each performance, combined with estimation of metabolic equivalent (MET) values using individual linear regression equations of HR-oxygen uptake. These equations were created using the results of 12 water activities. Blood lactate concentration and systolic blood pressure were measured at the 1/3 and 2/3 stages and immediately after each performance period. HR and estimated METs during DWS (mean±SD, 152.9±7.5 beats·min-1 and 7.3±1.2) were significantly higher than those measured during SWS (131.8±11.3 beats·min-1 and 5.7±0.8). Blood lactate concentration and systolic blood pressure measured immediately after DWS were significantly higher than those measured after SWS. With DWS, blood lactate concentration at the 2/3 stage and immediately after the performance were significantly higher than those measured at the 1/3 stage, whereas in SWS no significant difference was found in these values at any time period. In conclusion, the exercise intensity of DWS was high and SWS moderate. The predominant sources of energy may be phosphocreatine stores and aerobic metabolism during these performances. It is possible that glycolysis may also play an important role in energy requirements during the 2/3 stage and immediately after a DWS performance. © 2015, Japanese Society of Physical Fitness and Sports Medicine. All rights reserved. Source

Asakura H.,Japan National Institute of Health Sciences | Ekawa T.,Japan National Institute of Health Sciences | Sugimoto N.,Japan National Institute of Health Sciences | Momose Y.,Japan National Institute of Health Sciences | And 4 more authors.
Biochemical and Biophysical Research Communications | Year: 2012

Salmonella enterica serovar Typhimurium is a major cause of human gastrointestinal illness worldwide. This pathogen can persist in a wide range of environments, making it of great concern to public health. Here, we report that the salmonella pathogenicity island (SPI)-1 effector protein SipB exhibits a membrane topology that confers bacterial osmotolerance. Disruption of the sipB gene or the invG gene (SPI-1 component) significantly reduced the osmotolerance of S. Typhimurium LT2. Biochemical assays showed that NaCl osmolarity increased the membrane topology of SipB, and a neutralising antibody against SipB reduced osmotolerance in the WT strain. The WT strain, but not the sipB mutant, exhibited elevated cyclopropane fatty acid C19:0 during conditions of osmotic stress, correlating with the observed levels of survival and membrane integrity. This result suggests a link between SipB and the altered fatty acid composition induced upon exposure to osmotic stress. Overall, our findings provide the first evidence that the Salmonella virulence translocon SipB affects membrane fluidity and alters bacterial osmotolerance. © 2012 Elsevier Inc. Source

Asakura H.,Japan National Institute of Health Sciences | Kawamoto K.,Obihiro University of Agriculture and Veterinary Medicine | Murakami S.,Tokyo University of Agriculture | Tachibana M.,Japan National Institute of Health Sciences | And 4 more authors.
Research in Microbiology | Year: 2016

Campylobacter jejuni is one of the leading causes of foodborne gastrointestinal illness worldwide. Here we performed ex vivo proteomic analysis of C. jejuni 81-176 in chicken, a main reservoir for human infection. At 0, 1 and 4 weeks post-infection (p.i.) with the GFP-expressing 81-176 strain, inocula were recovered from chicken ceca by cell sorting using flow cytometry. iTRAQ-coupled 2D-LC-MS/MS analyses that detected 55 C. jejuni proteins, among which either 3 (FabG, HydB, CJJ81176_0876) or 7 (MscS, CetB, FlhF, PurH, PglJ, LpxC, Icd) proteins exhibited >1.4-fold-increased expression at 1 or 4 week(s) p.i. compared with those at 0 weeks p.i., respectively. Deletion of the fabG gene clearly decreased the proportion of bacterial unsaturated fatty acids (UFAs) and chicken colonization. The UFA proportion of the parental strain was not altered when grown at 42 °C. These findings suggest that FabG might play a pivotal role in UFA production, linked to bacterial adaptation in the poultry host. To our knowledge, this is the first example of ex vivo C. jejuni proteomics, in which fatty acid metabolism might affect bacterial adaptation to the chicken host. © 2015 Institut Pasteur. Source

Masuda K.,Japan National Institute of Health Sciences | Yamamoto S.,Japan National Institute of Health Sciences | Kubota K.,Japan National Institute of Health Sciences | Kurazono H.,Obihiro University of Agriculture and Veterinary Medicine | And 4 more authors.
Journal of Food Safety | Year: 2015

Following a large outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 infection in 2012, the prerequisite program for the production of pickles in Japan was revised to include disinfection with sodium hypochlorite (NaClO). Here, we examined the indicator bacterial counts, incidence of STEC and Salmonella spp. (by polymerase chain reaction [PCR] screening), and bacterial community composition (by 16S rRNA pyrosequencing analysis) from the intermediate products and the related facilities at a collaborative factory to evaluate the dynamics of microbial quality in lightly pickled vegetables during the manufacturing process following the revised program. Plate counts showed a significant reduction in coliform counts throughout processing, whereas the reduction in total viable counts was relatively less than that of coliforms. No STEC and Salmonella spp. were recovered from any of the samples. 16S rRNA pyrosequencing analysis revealed the process-by-process alteration of bacterial community composition in which the yields of Pseudomonas spp. were drastically affected by soaking in high concentration of NaCl. In summary, we demonstrate that the revised prerequisite program is indeed functional to reduce the microbial risks. © 2015 Wiley Periodicals, Inc. Source

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