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881.
Qingran Kong Meiling Wu Yanjun Huan Li Zhang Haiyan Liu Gerelchimeg Bou Yibo Luo Yanshuang Mu Zhonghua Liu 《PloS one》2009,4(8)
Transgenic animals have been used for years to study gene function, produce important proteins, and generate models for the study of human diseases. However, inheritance and expression instability of the transgene in transgenic animals is a major limitation. Copy number and promoter methylation are known to regulate gene expression, but no report has systematically examined their effect on transgene expression. In the study, we generated two transgenic pigs by somatic cell nuclear transfer (SCNT) that express green fluorescent protein (GFP) driven by cytomegalovirus (CMV). Absolute quantitative real-time PCR and bisulfite sequencing were performed to determine transgene copy number and promoter methylation level. The correlation of transgene expression with copy number and promoter methylation was analyzed in individual development, fibroblast cells, various tissues, and offspring of the transgenic pigs. Our results demonstrate that transgene expression is associated with copy number and CMV promoter methylation in transgenic pigs. 相似文献
882.
883.
Knowledge of digestion kinetics of solid foods in human stomach, as affected by food processing methods, is critical in establishing
processing conditions at the manufacturing stage to achieve desirable release of nutrients in the gastrointestinal tract.
The objective of this study was to investigate how roasting affected disintegration and solid release properties of almond
in simulated gastric environment. In vitro trials were performed for raw and roasted almonds by using static soaking method
and a model stomach system. The changes in sample weight, dry mass, and moisture during the trials were determined. Both compression
and penetration tests were used to investigate the texture of almonds with a focus on the influence of absorption of gastric
juice. Light microscopy and transmission electronic microscopy were used to study the change in microstructure of the raw
and roasted almonds after simulated digestion. The results suggested that the slow disintegration rate and the high amount
of swelling of the almonds in the stomach may contribute to their high satiety property. Roasting significantly improved the
disintegration rates of almonds and increased loss of solids during simulated digestion, which is well correlated with the
decrease in the rigidity of almond samples after absorbing gastric juice. Microstructure of digested almonds showed breakage
and breach of cell walls due to acid hydrolysis. Intercellular and intracellular channels formed in almonds during roasting
are important for penetration of gastric juice that may facilitate an effective digestion. 相似文献
884.
Ronald H. Gray David Serwadda Aaron A. R. Tobian Michael Z. Chen Frederick Makumbi Tara Suntoke Godfrey Kigozi Fred Nalugoda Boaz Iga Thomas C. Quinn Lawrence H. Moulton Oliver Laeyendecker Steven J. Reynolds Xiangrong Kong Maria J. Wawer 《PLoS medicine》2009,6(11)
Background
Randomized trials show that male circumcision (MC) reduces the incidence of HIV and herpes simplex virus type 2 (HSV-2) infections, and symptomatic genital ulcer disease (GUD). We assessed the role of GUD and HSV-2 in the protection against HIV afforded by MC.Methods and Findings
HIV-uninfected men were randomized to immediate (n = 2,756) or delayed MC (n = 2,775) in two randomized trials in Rakai, Uganda. GUD symptoms, HSV-2 status, and HIV acquisition were determined at enrollment and at 6, 12, and 24 mo of follow up. Ulcer etiology was assessed by PCR. We estimated the prevalence and prevalence risk ratios (PRRs) of GUD in circumcised versus uncircumcised men and assessed the effects of HSV-2 serostatus as a risk-modifying factor for GUD. We estimated the proportion of the effect of MC on HIV acquisition that was mediated by symptomatic GUD, and by HSV-2 infection. Circumcision significantly reduced symptomatic GUD in HSV-2-seronegative men (PRR = 0.51, 95% [confidence interval] CI 0.43–0.74), HSV-2-seropositive men (PRR = 0.66, 95% CI 0.51–0.69), and in HSV-2 seroconverters (PRR = 0.48, 95% CI 0.30–0.79). The proportion of acute ulcers due to HSV-2 detected by PCR was 48.0% in circumcised men and 39.3% in uncircumcised men (χ2 p = 0.62). Circumcision reduced the risk of HIV acquisition in HSV-2 seronegative men (incidence rate ratio [IRR] = 0.34, 95% CI 0.15–0.81), and potentially in HSV-2 seroconverters (IRR = 0.56, 95% CI 0.19–1.57; not significant), but not in men with prevalent HSV-2 at enrollment (IRR = 0.89, 95% CI 0.49–1.60). The proportion of reduced HIV acquisition in circumcised men mediated by reductions in symptomatic GUD was 11.2% (95% CI 5.0–38.0), and the proportion mediated by reduced HSV-2 incidence was 8.6% (95% CI −1.2 to 77.1).Conclusions
Circumcision reduced GUD irrespective of HSV-2 status, but this reduction played only a modest role in the protective effect of circumcision on HIV acquisition.NIH Trial registration
ClinicalTrials.gov NCT00425984Gates Foundation Trial registration
ClinicalTrials.gov Please see later in the article for the Editors'' Summary NCT00124878相似文献885.
Woo-Jin Kim Young-Ok Kim Bo-Hye Nam Hee Jeong Kong Eun-Mi Park Jung-Ha Kang Jeong-Ho Lee Kyung-Kil Kim 《Conservation Genetics》2009,10(4):1105-1111
Expressed sequence tags (ESTs) can be used to identify microsatellite markers. We developed 81 polymorphic microsatellite
markers from 4,940 ESTs of the olive flounder, Paralichthys olivaceus. Out of 100 EST-derived microsatellites for which PCR primers were designed, 81 loci were polymorphic in 30 individuals from
a single natural population with 2–28 (mean 10.6) alleles per locus. The observed and expected heterozygosities of these loci
were 0.033–1.000 and 0.033–0.965, respectively. Segregation analysis within a mapping family revealed non-amplifying null
alleles at five loci. These new EST-derived microsatellite markers should be useful for population genetic analyses, pedigree
tracing and constructing a linkage map for olive flounder. 相似文献
886.
Microbial eukaryotic community (0.8–20 μm) composition and its seasonal variation were investigated in large, shallow, subtropical
Lake Taihu located in Southeast China. The water samples were collected monthly from August 2006 to July 2007 at two sites
distantly located in Meiliang Bay and Lake Center, which differed strongly in their trophic status and sediment resuspension.
The microbial eukaryotic community compositions (MECC) were measured using denaturing gradient gel electrophoresis (DGGE)
of PCR-amplified eukaryotic 18S rRNA gene fragments. Seasonal variations were related to environmental factors by means of
redundancy analysis (RDA) in order to reveal the most important regulating factors. At both sites, the structures and Shannon–Wiener
indices of the microbial eukaryotic communities displayed apparent seasonal variations, which were significantly related to
environmental variables. There were significant intrahabitat differences in environmental factors regulating MECC, as well
as in the seasonal dynamics of the two sites during the study period. At Meiliang Bay, the variations of total phosphorus
concentration and cladocera abundance had the most profound impacts on the microbial eukaryotic community composition, while
at Lake Center, the total nitrogen concentration and conductivity were most influential. Our results suggest that the DGGE
method is a cost-effective way to analyze the seasonal dynamics of MECC and their interaction with environmental variables,
which will provide new insights into the diversity and dynamics of MECC. 相似文献
887.
Genetic variation and evolutionary demography of the shrimp Fenneropenaeus chinensis were investigated using sequence data of the complete mitochondrial control region (CR). Fragments of 993 bp of the CR were sequenced for 93 individuals from five localities over most of the species' range in the Yellow Sea and the Bohai Sea. There were 84 variable sites defining 68 haplotypes. Haplotype diversity levels were very high (0.95 ± 0.03-0.99 ± 0.02) in F. chinensis populations, whereas those of nucleotide diversity were moderate to low (0.66 ± 0.36%-0.84 ± 0.46%). Analysis of molecular variance and conventional population statistics (F(ST) ) revealed no significant genetic structure throughout the range of F. chinensis. Mismatch distribution, estimates of population parameters and neutrality tests revealed that the significant fluctuations and shallow coalescence of mtDNA genealogies observed were coincident with estimated demographic parameters and neutrality tests, in implying important past-population size fluctuations or range expansion. Isolation with Migration (IM) coalescence results suggest that F. chinensis, distributed along the coasts of northern China and the Korean Peninsula (about 1000 km apart), diverged recently, the estimated time-split being 12,800 (7,400-18,600) years ago. 相似文献
888.
Changzhong Li Yilin Hu Jian Liang Yawei Kong Jing Huang Qiaoli Feng Shuo Li Guiyou Zhang Liping Xie Rongqing Zhang 《Marine biotechnology (New York, N.Y.)》2010,12(1):100-110
Calcineurin (CN) is a multifunctional protein involved in many important physiological processes in mammalians, but the function
of CN in mollusks is still largely unknown. In the present study, through the shell regeneration system, the changes of enzymatic
activity of CN were determined in the process of shell regeneration in pearl oyster Pinctada fucata. CN was activated immediately and continuously in the shell regeneration process. The speed of shell regeneration was measured
and the ultrastructure of inner shell surface was observed by scanning electron microscopy after inhibiting CN by intramuscular
injection of immunosuppresant cyclosporine A (CsA). The results showed that the speed of shell regeneration was delayed and
the morphology of calcite and aragonite in the inner shell surface became abnormal when CN was inhibited by CsA. Meanwhile,
RT-PCR analysis revealed that the expression of P. fucata BMP-2 in mantle tissue decreased with CsA injection. In vitro secretion level of proteoglycans (PGs) in primary cultures
of mantle cells was also decreased when mantle cells were exposed to CsA. Taken together, our results, for the first time,
show that CN is involved in the shell formation through regulating the expression of Pf-BMP-2 in mantle tissue, which controls the secretion of PGs/GAGs of the mantle epithelial cells. 相似文献
889.
Wei Wei Kong Li Ping Zhang Kai Guo Zhao Pu Liu Zhi Min Yang 《Plant biotechnology journal》2010,8(1):88-99
Carbon monoxide (CO) is an endogenous gaseous molecule and regulates a variety of biological processes in animals. However, whether CO regulates nutrient stress responses in plants is largely unknown. In this paper, we described an observation that CO can regulate iron-homeostasis in iron-starved Arabidopsis. Exogenous CO at 50 μ m was able to prevent the iron deficient-induced chlorosis and improve chlorophyll accumulation. Expression of AtIRT1 , AtFRO2 , AtFIT1 and AtFER1 was up-regulated by CO exposure in iron-deficient seedlings. CO-regulated iron homeostasis could also be found in monocot maize and green alga Chlamydomonas reinhardtii . Treatment with external CO increased iron accumulation in iron-deficient Arabidopsis and C. reinhardtii , and restored leaf greening in Maize ys1 and ys3 mutants (defective in Fe uptake). Moreover, endogenous CO level was increased in Arabidopsis under iron-deficiency. Finally, CO exposure induced NO accumulation in root tips. However, such an action could be blocked by NO scavenger cPTIO. These results indicate that CO may play an important role in improving plant adaptation to iron deficiency or cross-talking with NO under the iron deficiency. 相似文献