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Yokouchi Y.,Japan National Institute of Environmental Studies | Nojiri Y.,Japan National Institute of Environmental Studies | Toom-Sauntry D.,Environment Canada | Fraser P.,CSIRO | And 5 more authors.
Geophysical Research Letters | Year: 2012

It has been suggested that the emissions of volatile organic compounds (VOCs) from the ocean could be affected by global warming, with feedback effects on the climate. In order to detect changes in their emissions as a response to global environmental change, long-term observations are required. Here we report for the first time long-term variations of atmospheric methyl iodide (CH 3I), the most abundant iodine-containing compound predominantly emitted from the ocean. We monitored its concentration periodically at five remote sites covering 82.5N-40.4S and over the western and northern Pacific Ocean from the late 1990s to 2011. At most observation sites, CH3I increased from 2003/2004 to 2009/2010 by several tens of per cent, with a decreasing trend before 2003. The inter-annual variation pattern is well approximated by a sine curve with a period of 11years and showed a good correlation with the Pacific Decadal Oscillation (PDO), suggesting that CH 3I emissions are affected by global-scale, sea surface temperature (SST)-related, decadal anomalies. The influence of natural oscillations or environmental change on trace gas emissions from the ocean may be greater than has been thought previously, and these emissions may thus be sensitive to future climate change. © 2012. American Geophysical Union. Source


Matsushima Y.,Kawasaki City Institute for Public Health | Matsushima Y.,Yokohama City University | Ishikawa M.,Kawasaki City Institute for Public Health | Shimizu T.,Kawasaki City Institute for Public Health | And 11 more authors.
Eurosurveillance | Year: 2015

A novel GII.P17-GII.17 variant norovirus emerged as a major cause of norovirus outbreaks from December 2014 to March 2015 in Japan. Named Hu/GII/JP/2014/GII.P17-GII.17, this variant has a newly identified GII. P17 type RNA-dependent RNA polymerase, while the capsid sequence displays amino acid substitutions around histo-blood group antigen (HBGA) binding sites. Several variants caused by mutations in the capsid region have previously been observed in the GII.4 genotype. Monitoring the GII.17 variant’s geographical spread and evolution is important. © 2015, European Centre for Disease Prevention and Control (ECDC). All Rights Reserved. Source


Noh N.-J.,Gifu University | Kuribayashi M.,Gifu University | Kuribayashi M.,Nagano Environmental Conservation Research Institute | Saitoh T.M.,Gifu University | And 4 more authors.
Ecosystems | Year: 2015

How global warming will affect soil respiration (RS) and its source components is poorly understood despite its importance for accurate prediction of global carbon (C) cycles. We examined the responses of RS, heterotrophic respiration (RH), autotrophic respiration (RA), nitrogen (N) availability, and fine-root biomass to increased temperature in an open-field soil warming experiment. The experiment was conducted in a cool-temperate deciduous forest ecosystem in northern Japan. As this forest is subjected to strong temporal variation in temperature, on scales ranging from daily to seasonal, we also investigated the temporal variation in the effects of soil warming on RS, RH, and RA. Soil temperature was continuously elevated by about 4.0°C from 2007 to 2014 using heating wires buried in the soil, and we measured soil respiratory processes in all four seasons from 2012 to 2014. Soil warming increased annual RS by 32–45%, but the magnitude of the increase was different between the components: RH and RA were also stimulated, and increased by 39–41 and 17–18%, respectively. Soil N availability during the growing season and fine-root biomass were not remarkably affected by the warming treatment. We found that the warming effects varied seasonally. RH increased significantly throughout the year, but the warming effect showed remarkable seasonal differences, with the maximum stimulation in the spring. This suggests that warmer spring temperature will produce a greater increase in CO2 release than warmer summer temperatures. In addition, we found that soil warming reduced the temperature sensitivity (Q10) of RS. Although the Q10 of both RH and RA tended to be reduced, the decrease in the Q10 of RS was caused mainly by a decrease in the response of RA to warming. These long-term results indicate that a balance between the rapid and large response of soil microbes and the acclimation of plant roots both play important roles in determining the response of RS to soil warming, and must be carefully considered to predict the responses of soil C dynamics under future temperature conditions. © 2015 Springer Science+Business Media New York Source


Amemura-Maekawa J.,Japan National Institute of Infectious Diseases | Kikukawa K.,Saitama Prefectural University | Helbig J.H.,TU Dresden | Helbig J.H.,Nippon Medical School | And 14 more authors.
Applied and Environmental Microbiology | Year: 2012

Legionella pneumophila serogroup (SG) 1 is the most frequent cause of legionellosis. This study analyzed environmental isolates of L. pneumophila SG 1 in Japan using monoclonal antibody (MAb) typing and sequence-based typing (SBT). Samples were analyzed from bathwater (BW; n=50), cooling tower water (CT; n=50), and soil (SO; n=35). The distribution of MAb types varied by source, with the most prevalent types being Bellingham (42%), Oxford (72%), and OLDA (51%) in BW, CT, and SO, respectively. The ratios of MAb 3/1 positive isolates were 26, 2, and 14% from BW, CT, and SO, respectively. The environmental isolates from BW, CT, and SO were divided into 34 sequence types (STs; index of discrimination [IOD]=0.973), 8 STs (IOD= 0.448), and 11 STs (IOD=0.879), respectively. Genetic variation among CT isolates was smaller than seen in BW and SO. ST1 accounted for 74% of the CT isolates. The only common STs between (i) BW and CT, (ii) BW and SO, and (iii) CT and SO were ST1, ST129, and ST48, respectively, suggesting that each environment constitutes an independent habitat. © 2012, American Society for Microbiology. Source


Yokoyama E.,Chiba Prefectural Institute of Public Health | Etoh Y.,Fukuoka Institute of Health Environmental | Ichihara S.,Fukuoka Institute of Health Environmental | Horikawa K.,Fukuoka Institute of Health Environmental | And 7 more authors.
Journal of Food Protection | Year: 2011

Enterohemorrhagic Escherichia coli serovar O157 (O157) strains with highly similar pulsed-field gel electrophoresis (PFGE) patterns were isolated in Japan during 2007 and 2008. Several genetic features related to O157 evolution were investigated to indicate whether homoplasy might have contributed to the highly similar PFGE patterns in these strains. The O157 strains were classified in lineage I/II, as defined by a lineage-specific polymorphism assay-6 with an atypical allele in Z5935 (code: 231111). Analysis of the insertion sites of stx 2 phage in these strains showed that the sites were "occupied" in yehV and "intact" in wrbA, indicating that the strains were derived from "Cluster 1" of "Subgroup C." When a specific single-nucleotide polymorphism in ECs2357 in clade 8 strains was investigated, all of the strains in the present study were confirmed to be clade 8 strains. These results indicated that the O157 strains in this study had common genetic features, suggesting that the highly similar PFGE patterns of these strains were not due to homoplasy. Because no common source of these strains could be identified in 2007 to 2008 in Japan, these strains may have emerged from a unique O157 clade 8 clone and then spread by dissemination in Japan. © International Association for Food Protection. Source

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