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101.
102.
Hiroko Yamada Kazuaki Takahashi Olline Lim Somana Svay Channarena Chuon Sirany Hok Son Huy Do Mayumi Fujimoto Tomoyuki Akita Noboru Goto Keiko Katayama Masahiro Arai Junko Tanaka 《PloS one》2015,10(8)
Hepatitis E virus (HEV) is a growing public health problem in many countries. In this study, we investigated HEV seroprevalence among the general population in the Siem Reap province, Cambodia, and performed HEV genetic analysis with the aim to develop an HEV prevention strategy. This seroepidemiological cross-sectional study conducted from 2010 to 2014 included 868 participants from four different locations in Siem Reap province, Cambodia. They answered questionnaires and provided blood samples for the analysis of hepatitis virus infections. Among the participants (360 men and 508 women; age range, 7–90 years), the prevalence of anti-HEV IgG was 18.4% (95% confidence interval: 15.9–21.0); HEV RNA was detected in two participants (0.23%) and was classified as genotype 3 and 4. Full-length genome of the genotype 4 isolate, CVS-Sie10, was sequenced; it contained 7,222 nucleotides and three ORFs and demonstrated high sequence identity with the swine China isolates swGX40 (95.57%), SS19 (94.37%), and swDQ (91.94%). Multivariate logistic regression analysis revealed that men, elderly people, and house workers were risk groups significantly associated with the positivity for anti-HEV IgG. This is the first report on the detection of HEV genotype 4 in humans in Cambodia and on the complete genome sequence of HEV genotype 4 from this country. Our study demonstrates that new HEV infection cases occur frequently among the general population in Cambodia, and effective preventive measures are required. 相似文献
103.
104.
Heung-Min Son MooChang Kook Hanh T.H. Tran Ki-Young Kim Sang-Yong Park Ju-Han Kim Tae-Hoo Yi 《Antonie van Leeuwenhoek》2014,105(4):791-797
A Gram-staining negative bacterium, THG-DT81T, which was isolated from soil of a ginseng field, was investigated using a polyphasic taxonomic approach. Cells were oxidase- and catalase-positive, aerobic, rod-shaped and motile with one polar flagellum. Strain THG-DT81T grew optimally at pH 7.0 and in the absence of NaCl on trypticase soy agar. Its optimum growth temperature was 25–28 °C. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain THG-DT81T belongs to the family Sphingomonadaceae and was related to Sphingomonas pituitosa EDIVT (98.0 % similarity), S. leidyi ATCC 15260T (97.8 %), S. trueperi LMG 2142T (97.1 %), S. azotifigens NBRC 15497T (97.1 %), S. koreensis JSS26 T (97.1 %) and S. dokdonensis DS-4T (97.0 %). Strain THG-DT81T contained Q-10 as the predominant ubiquinone and C18:1 ω7c and C16:0 as the major fatty acids. The G+C content of the genomic DNA was determined to be 66.8 mol %. The major component in the polyamine pattern was identified as sym-homospermidine. The major polar lipids detected in strain THG-DT81T were sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylcholine. The DNA–DNA relatedness values of the strain THG-DT81T and its closest phylogenetically neighbors were below 21 %. The phenotypic characteristics and genotypic data demonstrated the affiliation of strain THG-DT81T to the genus Sphingomonas. On the basis of the polyphasic taxonomic data presented, strain THG-DT81T is described as a novel species of genus Sphingomonas, for which the name Sphingomonas kyeonggiense sp. nov. is proposed. The type strain is THG-DT81T (= KACC 17173T = JCM 18825T). 相似文献
105.
Eun-Jung Kim Hyeoncheol Francis Son Sangwoo Kim Jae-Woo Ahn Kyung-Jin Kim 《Biochemical and biophysical research communications》2014
ReBktB is a β-keto thiolase from Ralstonia eutropha H16 that catalyzes condensation reactions between acetyl-CoA with acyl-CoA molecules that contains different numbers of carbon atoms, such as acetyl-CoA, propionyl-CoA, and butyryl-CoA, to produce valuable bioproducts, such as polyhydroxybutyrate, polyhydroxybutyrate-hydroxyvalerate, and hexanoate. We solved a crystal structure of ReBktB at 2.3 Å, and the overall structure has a similar fold to that of type II biosynthetic thiolases, such as PhbA from Zoogloea ramigera (ZrPhbA). The superposition of this structure with that of ZrPhbA complexed with CoA revealed the residues that comprise the catalytic and substrate binding sites of ReBktB. The catalytic site of ReBktB contains three conserved residues, Cys90, His350, and Cys380, which may function as a covalent nucleophile, a general base, and second nucleophile, respectively. For substrate binding, ReBktB stabilized the ADP moiety of CoA in a distinct way compared to ZrPhbA with His219, Arg221, and Asp228 residues, whereas the stabilization of β-mercaptoethyamine and pantothenic acid moieties of CoA was quite similar between these two enzymes. Kinetic study of ReBktB revealed that Km, Vmax, and Kcat values of 11.58 μM, 1.5 μmol/min, and 102.18 s−1, respectively, and the catalytic and substrate binding sites of ReBktB were further confirmed by site-directed mutagenesis experiments. 相似文献
106.
Nam Jin Noh Yowhan Son Jin Woo Koo Kyung Won Seo Rae Hyun Kim Yoon Young Lee Kyung Seun Yoo 《Journal of Plant Biology》2010,53(1):61-69
The nitrogenase activity, root nodule biomass, and rates of nitrogen (N) fixation were measured in 25-year-old pure north-
and south-facing Robinia pseudoacacia stands in an urban forest of Seoul (Kkachisan Mountain) in central Korea. The nitrogenase activity was estimated using an
acetylene reduction (AR) assay, which showed an increasing trend during the early growing season, with sustained high rates
from June through to September with a decrease thereafter. July had the highest nitrogenase activity rate (micromoles C2H4 per gram dry nodule per hour), averaging 95.8 and 115.1 for the north- and south-facing stands, respectively. The maximum
root nodule biomass (kilograms per hectare) was 45.7 and 9.1 for the north- and south-facing stands in July, respectively.
The AR rate appeared to be strongly correlated to the soil temperature (r
2 = 0.68, P < 0.001) and soil pH (r
2 = 0.59, P < 0.001) while root nodule biomass was correlated to the soil temperature (r
2 = 0.36, P < 0.01) and water content (r
2 = 0.35, P < 0.05). The soil temperature showed clear differences between seasons, while there was a significant difference in soil pH,
organic matter, total N concentrations, and available phosphorus between the north- and south-facing stands. The N2 fixation rates during the growing season varied from 0.1 to 37.5 kg N ha−1 month−1 depending on the sampling location and time. The annual N2 fixation rate (kg N per hectare per year) was 112.3 and 23.2 for the north- and south-facing stands, respectively. The differences
in N2 fixation rate between the two stands were due mainly to the differences in total nodule biomass. 相似文献
107.
Autotrophic and heterotrophic respiration in needle fir and Quercus-dominated stands in a cool-temperate forest, central Korea 总被引:3,自引:0,他引:3
Na-yeon Lee Jin-Woo Koo Nam Jin Noh Joon Kim Yowhan Son 《Journal of plant research》2010,123(4):485-495
To investigate annual variation in soil respiration (R
S) and its components [autotrophic (R
A) and heterotrophic (R
H)] in relation to seasonal changes in soil temperature (ST) and soil water content (SWC) in an Abies holophylla stand (stand A) and a Quercus-dominated stand (stand Q), we set up trenched plots and measured R
S, ST and SWC for 2 years. The mean annual rate of R
S was 436 mg CO2 m−2 h−1, ranging from 76 to 1,170 mg CO2 m−2 h−1, in stand A and 376 mg CO2 m−2 h−1, ranging from 82 to 1,133 mg CO2 m−2 h−1, in stand Q. A significant relationship between R
S and its components and ST was observed over the 2 years in both stands, whereas a significant correlation between R
A and SWC was detected only in stand Q. On average over the 2 years, R
A accounted for approximately 34% (range 17–67%) and 31% (15–82%) of the variation in R
S in stands A and Q, respectively. Our results suggested that vegetation type did not significantly affect the annual mean
contributions of R
A or R
H, but did affect the pattern of seasonal change in the contribution of R
A to R
S. 相似文献
108.
Nam Jin Noh Yowhan Son Sue Kyoung Lee Tae Kyung Yoon Kyung Won Seo Choonsig Kim Woo-Kyun Lee Sang Won Bae Jaehong Hwang 《Journal of plant research》2010,123(4):411-419
We investigated the influence of stand density [938 tree ha−1 for high stand density (HD), 600 tree ha−1 for medium stand density (MD), and 375 tree ha−1 for low stand density (LD)] on soil CO2 efflux (R
S) in a 70-year-old natural Pinus densiflora S. et Z. forest in central Korea. Concurrent with R
S measurements, we measured litterfall, total belowground carbon allocation (TBCA), leaf area index (LAI), soil temperature
(ST), soil water content (SWC), and soil nitrogen (N) concentration over a 2-year period. The R
S (t C ha−1 year−1) and leaf litterfall (t C ha−1 year−1) values varied with stand density: 6.21 and 2.03 for HD, 7.45 and 2.37 for MD, and 6.96 and 2.23 for LD, respectively. In
addition, R
S was correlated with ST (R
2 = 0.77–0.80, P < 0.001) and SWC (R
2 = 0.31–0.35, P < 0.001). It appeared that stand density influenced R
S via changes in leaf litterfall, LAI and SWC. Leaf litterfall (R
2 = 0.71), TBCA (R
2 = 0.64–0.87), and total soil N contents in 2007 (R
2 = 0.94) explained a significant amount of the variance in R
S (P < 0.01). The current study showed that stand density is one of the key factors influencing R
S due to the changing biophysical and environmental factors in P. densiflora. 相似文献
109.
The carbon (C) and nitrogen (N) status in forest ecosystems can change upon establishment of plantations because different
tree species have different nutrient cycling mechanisms. This study was carried out to evaluate C and N status of litterfall,
litter decomposition and soil in three adjacent plantations consisting of one deciduous (larch: Larix leptolepis) and two evergreen (red pine: Pinus densiflora; rigitaeda pine: P. rigida × P. taeda) species planted in the same year (1963). Both the pine plantations showed comparatively higher C input from needle litter
but significantly lower N concentration and input than the larch plantation (P < 0.05). During the decomposition process, the deciduous larch needle litter showed low C concentration and C remaining in
soil, but high N concentration and N remaining in soil compared to the two evergreen pine needle litters. However, the soil
C and N concentration and their content at a soil depth of 0–10 cm were not affected significantly (P > 0.05) by the plantation type. These results demonstrate the existence of considerable variation in C and N status resulting
from needle litter input and litter decomposition in these three plantations grown at sites with similar environmental conditions. 相似文献
110.
Sang Hoon Jeong Jae Hwan Kim Sang Min Yi Jin Ho Kim Kui Lea Park Sang Wook Son 《Biochemical and biophysical research communications》2010,394(3):612-615
Quantum dots (QDs) are rapidly emerging as an important class of nanoparticles (NPs) with potential applications in medicine. However, little is known about penetration of QDs through human skin. This study investigated skin penetration of QDs in both in vivo and in vitro human skin. Using the tape stripping method, this study demonstrates for the first time that QDs can actually penetrate through the stratum corneum (SC) of human skin. Transmission electron microscope (TEM) and energy diverse X-ray (EDX) analysis showed accumulation of QDs in the SC of a human skin equivalent model (HSEM) after dermal exposure to QDs. These findings suggest possible transdermal absorption of QDs after dermal exposure over a relatively long period of time. 相似文献