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Hou, Chen Yuan,Kang, Taek Jin John WileySons, Ltd 2018 Journal of chemical technology and biotechnology Vol.93 No.1
<P>CONCLUSIONIt is possible to convert crude glycerol into GABA in a growth-associated manner using E. coli W, and the strain will serve as a base strain for future metabolic engineering approaches. (c) 2017 Society of Chemical Industry</P>
Selection of Escherichia coli Glutamate Decarboxylase Active at Neutral pH from a Focused Library
Chen Yuan Hou,안치윤,조병관,강택진 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.4
Bacterial glutamate decarboxylase (GAD) converts glutamate (Glu) into γ-aminobutyric acid (GABA) at acidic conditions. Since the reaction consumes a proton per GABA synthesis, cells use this reaction to survive in the acidic environments. Characteristically, the enzyme displays a sigmoidal decrease in its activity as pH rises becoming completely inactive at or above pH 6. This cooperative activity loss is accompanied by several distinct structural changes. Previously, by examining structures at acidic and neutral pH, two key regions had been chosen and mutated to break the cooperativity; Glu89 and C-terminal 15 residues. In this study, we included Asp86 in candidate key residues for mutation to break the cooperativity of GAD. We devised a selection strategy according to which only Escherichia coli cells expressing a variant GAD that was active at neutral pH could survive. In this scheme, an alanine (Ala) auxotroph was rescued by the intracellular synthesis of GABA that was subsequently converted into Ala by heterologously expressed GABA-pyruvate transaminase. New GAD variants were readily selected using this strategy and the most of them indeed had a mutation at residue 86. The results suggest that the role of Asp86 in the wild-type enzyme might be the same as Glu89; to make GAD keep its activity only at acidic environments. Characterization of representative variants are also presented.
( Yuan Wei ),( Zhi Peng Chen ),( Feng Chang Wu ),( Ji Ning Li ),( Yu Xian Shangguan ),( Fa Sheng Li ),( Qing Ru Zeng ),( Hong Hou ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8
Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the symbiosis of AMF associated with an antimony (Sb) accumulator plant under natural conditions. Therefore, the objective of this study was to investigate the colonization and molecular diversity of AMF associated with the Sb accumulator ramie (Boehmeria nivea) growing in Sb-contaminated soils. Four Sb mine spoils and one adjacent reference area were selected from Xikuangshan in southern China. PCR-DGGE was used to analyze the AMF community composition in ramie roots. Morphological identification was also used to analyze the species in the rhizosphere soil of ramie. Results obtained showed that mycorrhizal symbiosis was established successfully even in the most heavily polluted sites. From the unpolluted site Ref to the highest polluted site T4, the spore numbers and AMF diversity increased at first and then decreased. Colonization increased consistently with the increasing Sb concentrations in the soil. A total of 14 species were identified by morphological analysis. From the total number of species, 4 (29%) belonged to Glomus, 2 (14%) belonged to Acaulospora, 2 (14%) belonged to Funneliformis, 1 (7%) belonged to Claroideoglomus, 1 (7%) belonged to Gigaspora, 1 (7%) belonged to Paraglomus, 1 (7%) belonging to Rhizophagus, 1 (7%) belonging to Sclervocystis, and 1 (7%) belonged to Scutellospora. Some AMF sequences were present even in the most polluted site. Morphological identification and phylogenetic analysis both revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant genus in this AMF community. This study demonstrated that ramie associated with AMF may have great potential for remediation of Sb-contaminated soils.
Chen, Yin Bin,Wang, Yu Fang,Hou, Wei,Wang, Ying Ping,Xiao, Sheng Yuan,Fu, Yang Yang,Wang, Jia,Zheng, Si Wen,Zheng, Pei He The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.2
Background: Both ginsenoside Re and B-complex vitamins are widely used as nutritional supplements. They are often taken together so as to fully utilize their antifatigue and refreshing effects, respectively. Whether actually a drug-nutrient interaction exists between ginsenoside Re and B-complex vitamins is still unknown. The objective of this study was to simultaneously investigate the effect of B-complex vitamins on the antifatigue activity and bioavailability of ginsenoside Re after their oral administration. The study results will provide valuable theoretical guidance for the combined utilization of ginseng and B-complex vitamins. Methods: Ginsenoside Re with or without B-complex vitamins was orally administered to mice to evaluate its antifatigue effects and to rats to evaluate its bioavailability. The antifatigue activity was evaluated by the weight-loaded swimming test and biochemical parameters, including hepatic glycogen, plasma urea nitrogen, and blood lactic acid. The concentration of ginsenoside Re in plasma was determined by liquid chromatography-tandem mass spectrometry. Results: No antifatigue effect of ginsenoside Re was noted when ginsenoside Re in combination with B-complex vitamins was orally administered to mice. B-complex vitamins caused to a reduction in the bioavailability of ginsenoside Re with the area under the concentration-time curve from zero to infinity markedly decreasing from $11,830.85{\pm}2,366.47h{\cdot}ng/mL$ to $890.55{\pm}372.94h{\cdot}ng/mL$. Conclusion: The results suggested that there were pharmacokinetic and pharmacodynamic drug-nutrient interactions between ginsenoside Re and B-complex vitamins. B-complex vitamins can significantly weaken the antifatigue effect and decrease the bioavailability of ginsenoside Re when simultaneously administered orally.
Guohu Chen,Xinyu Ye,Fanli Zeng,Jian Wang,Lingyun Yuan,Shidong Zhu,Jinfeng Hou,Yuan Cheng,Chenggang Wang 한국원예학회 2019 Horticulture, Environment, and Biotechnology Vol.60 No.3
The novel male sterility line 12-14A of Wucai ( Brassica campestris ) was generated by backcrossing. In this study, morphological,molecular, and cytological analyses were performed to characterize this line. The phenotypes of fl ower organsof 12-14A were diff erent from those of its maintainer line 12-14B, as the fl owers of 12-14A were completely infertile. Molecular analysis confi rmed that the male sterility line 12-14A was classifi ed as the ogu CMS type. An analysis of antherdevelopment in the CMS line demonstrated that two types of abortion occur simultaneously: pollen mother cell abortionand tetrad-to-mononuclear microspore abortion. In addition, the mature anthers of 12-14A showed typical abortive features,such as appearing dry, shrunken, and scaly. A heterosis test of hybrids from CMS 12-14A and four inbred lines was carriedout, and the F 1 hybrids exhibited clear heterosis in plant weight, as well as in the protein, soluble sugar, and vitamin C content,suggesting high yields and high quality potential. These results indicate that this novel CMS line may have powerfulpotential in Wucai hybrid breeding.
Seroprevalence of Dirofilaria immitis in Cats from Liaoning Province, Northeastern China
Honglie Hou,Lili Cao,Wenzhi Ren,Dansheng Wang,He Ding,Juan You,Xinhua Yao,Hang Dong,Yanbing Guo,Shuxian Yuan,Xi-Chen Zhang,Pengtao Gong 대한기생충학ㆍ열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.6
The present study was performed to investigate the seroprevalence and risk factors for Dirofilaria immitis infection in cats from Liaoning province, northeastern China. From October 2014 to September 2016, sera of 651 cats, including 364 domestic cats and 287 feral cats (332 females and 319 males) were assessed. They were tested for the presence of D. immitis antigen using SNAP Heartworm RT test kit. In this population, the average prevalence was 4.5%. Age and rearing conditions (feral or domestic) were found to be associated with the prevalence of D. immitis. The prevalence was significantly higher in feral cats compared with domestic cats (8.4% vs 1.4%, P<0.01). There was no significant difference between males and females (4.7% vs 4.2%, P>0.05), but older cats (≥3 years old) showed a statistically higher prevalence compared with younger cats (<3 years old) in feral populations (16.8 vs 2.4%, P<0.01), while the difference between the age groups was not statistically significant in domestic cats (2.4% vs 0.51%, P>0.05), all these results suggest that outdoor exposure time may be one of the most important factors for D. immitis prevalence in cats. Results reveal that D. immitis are prevalence in domestic and feral cats in northeastern China, which indicates that appropriate preventive measures should be taken to decrease the incidence of feline heartworm disease in Liaoning province, northeastern China.