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Search Results: 1 - 10 of 11354 matches for " Laijun Xing "
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Xing Laijun,

菌物学报 , 1995,
Abstract: Chemical herbicides are effective and immediate solution for controlling weed encroachment in the fields but the results often inconclusive and environmentally unacceptable. Biological control by the use of pathogenic fungi can be considered as an effective alternate weed-control method, and some commercialized mycoherbicides are now being used in several countries. Biological control of weeds will provide a new research field for mycology and plant pathology. In this paper the current research advances, problems and prospect of mycoherbicides are briefly reviewed and discussed.
The Effect of a High-Frequency-Hearing-Threshold Weighted Value on the Diagnosis of Occupational-Noise-Induced Deafness  [PDF]
Laijun Xue, Yanhong Zhang, Aichu Yang
Journal of Biosciences and Medicines (JBM) , 2018, DOI: 10.4236/jbm.2018.612009
Objective: In order to provide a theoretical basis for the revision of the current diagnostic criteria for occupational noise-induced deafness (ONID), we evaluated the degree of ONID by analyzing different high-frequency-hearing- threshold-weighted values (HFTWVs). Methods: A retrospective study was conducted to evaluate the diagnosis of patients with ONID from January 2016 to January 2017 in Guangdong province, China. Based on 3 hearing tests (each interval between the tests was greater than 3 days), the minimum threshold value of each frequency was obtained using the 2007 edition’s diagnostic criteria for ONID. The speech frequency and the HFTWVs were analyzed based on age, noise exposure, and diagnostic classi-fication using SPSS21.0. Results: 168 patients in total were involved in this study, 154 males and 14 females, and the average age was 41.18 ± 6.07. The diagnosis rate was increased by the weighted value of the high frequencies and was more than the mean value of the pure speech frequency (MVPSF). The diagnosis rate for the weighted 4 kHz frequency level increased by 13.69% (χ2 = 9.880, P = 0.002), the weighted 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002), and the weighted 4 kHz + 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002). The differences were all statistically significant. The diagnostic rate of the different thresholds showed no obvious difference between the genders. The age groups were divided into less than or equal to 40 years old (group A) and 40 - 50 years old (group B). There were several groups with a high frequency: high frequency weighted 4 kHz ( group A χ2 = 3.380, P = 0.050; group B χ2 = 4.054, P = 0.032), high frequency weighted 6 kHz (group A χ2 = 6.362, P = 0.012; group B χ2 = 4.054, P = 0.032), weighted 4 kHz + 6 kHz (group A χ2 = 6.362 P = 0.012; B χ2 = 4.054, P = 0.032) than those of MVPSF in the same group on ONID diagnosis rate. The differences between the groups were statistically significant. There was no significant difference between the age groups (χ2 = 2.265, P = 0.944). The better ear’s (the smaller hearing threshold weighted value) MVPSF and the weighted values for the different high frequencies were examined in light of the number of working years; the group that was exposed to noise for more than 10 years had significantly
Cloning and expression in Saccharomyces cerevisiae of D5-fatty acid desaturase gene from Phaeodactylum tricornutum

Zhe Yang,Dongsheng Wei,Laijun Xing,Mingchun Li,

生物工程学报 , 2009,
Abstract: D5-脂肪酸脱氢酶是合成花生四烯酸的关键酶。根据已报道的D 5-脂肪酸脱氢酶基因设计引物, 分别从三角褐指藻基因组DNA和总cDNA中扩增得到1520 bp和1410 bp的特异片段, 序列分析结果显示, 结构基因中含有一个大小为110 bp的内含子, 这是国内外首次报道。将D5-脂肪酸脱氢酶基因亚克隆到大肠杆菌和酿酒酵母的穿梭表达载体pYES2.0中, 在大肠杆菌中筛选到含有目的片段的重组质粒pYPTD5, 用电击转化的方法将重组质粒pYPTD5转化到营养缺陷型酿酒酵母菌株INVSc1中, 在缺省培养基中筛选得到酿酒酵母转化菌株YPTD5。在合适的培养条件下, 添加外源底物双高g-亚麻酸和诱导物半乳糖, 培养并收集菌体。通过脂肪酸甲酯气相色谱分析, 表明三角褐指藻D5-脂肪酸脱氢酶基因在酿酒酵母中获得了高效的表达, 将双高g-亚麻酸转化为花生四烯酸, 其底物转化率达到了45.9%。
Progress on molecular biology of trehalose synthase-A review

Yueming Zhu,Jun Zhang,Laijun Xing,Mingchun Li,

微生物学报 , 2009,
Abstract: Trehalose synthase inverts maltose into trehalose, and plays a very important role in trehalose industrial production. Here we reviewed the recent progress on studies of molecular biology including the cloning of trehalose synthase gene, gene engineering application, structure and catalytic mechanism and the role of the enzyme in vivo.
Transformation system of Aspergillus japonicus mediated by Agrobacterium tumefaciens

Hui Guo,Zhe Yang,Laijun Xing,Mingchun Li,

微生物学报 , 2011,
Abstract: Abstract: Objective]n order to select Aspergillus japonicus mutant strains that express high-yield of glycerol oxidase, we constructed a mutant library of Aspergillus japonicus that mediated by Agrobacterium tumefaciens. Methods]Tri-relative hybridization experiments were performed to transfer binary vector pBI-hphII into Agrobacterium tumefaciens EHA105, which was used as the infective strain and Aspergillus japonicus was used as the host strain. We established the transformation system of Aspergillus japonicus mediated by Agrobacterium tumefaciens and constructed a mutant library. At the same time, we analyzed the factors affecting the transformation efficiency such as the concentration of Agrobacterium tumefaciens, adding and not adding Acetosyringone, co-culture time, co-culture temperature and so on. Results]The results of PCR detection and Southern analysis showed that the T-DNA was integrated into genome of the Aspergillus japonicus. All of the nine randomly selected transformants were quite stable after ten rounds of successive cultures. Conclusion]The transformation system is a good basis for selection of Aspergillus japonicus mutant strains which give a high-yield of glycerol oxidase.

LI Mingchun,JIANG Heng,HOU Wenqiang,XING Laijun,

菌物学报 , 1998,
Abstract: 南开大学生命科学学院微生物系 天津 300071)摘要 以6属33株酵母菌的活菌或死菌对重金属离子Cu2+、Cd2+和Ni2+进行了吸附能力的初步研究。结果显示:吸附时间、吸附温度、溶液的pH共存离子和菌体的生理状态对吸附作用都有明显的影响。在优化组合后发现一株假丝酵母菌对三种重金属离子的吸附比为Cd2+>Cu2+>Ni2+,每克活菌体吸附量分别为17.23mg>10.57mg>3.2mg。干菌体对三种重金属的吸附量较明显的低于活菌体的吸附量。
Aft2, a Novel Transcription Regulator, Is Required for Iron Metabolism, Oxidative Stress, Surface Adhesion and Hyphal Development in Candida albicans
Ning Xu, Xinxin Cheng, Qilin Yu, Kefan Qian, Xiaohui Ding, Ruming Liu, Biao Zhang, Laijun Xing, Mingchun Li
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062367
Abstract: Morphological transition and iron metabolism are closely relevant to Candida albicans pathogenicity and virulence. In our previous study, we demonstrated that C. albicans Aft2 plays an important role in ferric reductase activity and virulence. Here, we further explored the roles of C. albicans Aft2 in numerous cellular processes. We found that C. albicans Aft2 exhibited an important role in iron metabolism through bi-directional regulation effects on iron-regulon expression. Deletion of AFT2 reduced cellular iron accumulation under iron-deficient conditions. Furthermore, both reactive oxygen species (ROS) generation and superoxide dismutase (SOD) activity were remarkably increased in the aft2Δ/Δ mutant, which were thought to be responsible for the defective responses to oxidative stress. However, we found that over-expression of C. albicans AFT2 under the regulation of the strong PGK1 promoter could not effectively rescue Saccharomyces cerevisiae aft1Δ mutant defects in some cellular processes, such as cell-wall assembly, ion homeostasis and alkaline resistance, suggesting a possibility that C. albicans Aft2 weakened its functional role of regulating some cellular metabolism during the evolutionary process. Interestingly, deletion of AFT2 in C. albicans increased cell surface hydrophobicity, cell flocculation and the ability of adhesion to polystyrene surfaces. In addition, our results also revealed that C. albicans Aft2 played a dual role in regulating hypha-specific genes under solid and liquid hyphal inducing conditions. Deletion of AFT2 caused an impaired invasive growth in solid medium, but an increased filamentous aggregation and growth in liquid conditions. Moreover, iron deficiency and environmental cues induced nuclear import of Aft2, providing additional evidence for the roles of Aft2 in transcriptional regulation.
Research focuses and advance technologies of smart grid in recent years
ShengWei Mei,LaiJun Chen
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5261-5
Abstract: The smart grid is attracting more and more attention in electrical engineering for its promising features. However, huge challenges also exist in the implementations of the smart grid, such as high penetration of renewable energy resources, low carbon electricity and cyber-physical security, etc. In this paper, the latest progress of some research focuses and advance technologies in the development of smart grid is reviewed.
Effects of low temperature and exogenous unsaturated fatty acids on fatty acid desaturase gene expression of Mortierella alpina ATCC 16266

Aiqun Yu,Tonglei Shi,Biao Zhang,Laijun Xing,Mingchun Li,

微生物学报 , 2012,
Abstract: 【目的】在转录水平上研究低温和外源不饱和脂肪酸对于高山被孢霉脂肪酸脱氢酶基因的表达调控机制。【方法】通过实时定量PCR技术和启动子报告基因融合载体的方法,研究低温和外源不饱和脂肪酸对于高山被孢霉3种脂肪酸脱氢酶基因表达随时间进程的影响。【结果】实时定量PCR的结果表明:低温对于3种脂肪酸脱氢酶基因的转录具有激活作用,外源不饱和脂肪酸对基因转录起抑制作用,而且这两种作用都是快速响应的,随时间延长逐渐减弱并消失。脂肪酸组成测定结果证明了基因转录水平变化与对应产物变化之间没有相关性。低温能够在短时间内诱导pFAD6启动子活性增加,并随时间延长而持续增强;外源不饱和脂肪酸对pFAD6启动子活性起抑制作用,其不饱和度和浓度越高,抑制作用越强,而且抑制作用是快速且持续的。【结论】低温和外源不饱和脂肪酸除了在转录水平上调控高山被孢霉脂肪酸脱氢酶基因表达发生变化之外,可能主要在转录后水平上介导了胞内脂肪酸组成的变化。而且,脂肪酸脱氢酶基因的表达可能受到胞内脂肪酸组成变化的反馈调节作用。本文首次在转录水平上对高山被孢霉脂肪酸脱氢酶基因的表达调控机制进行了探索,为深入了解脂肪酸脱氢酶基因表达及多不饱和脂肪酸合成对外界信号的应答机制提供了有用信息,也对应用微生物发酵和转基因技术生产不饱和脂肪酸具有指导意义。
Ferric reductase FRP1 gene in Candida albicans

Yong Liang,Wen Zheng,Dongsheng Wei,Laijun Xing,Mingchun Li,

微生物学报 , 2009,
Abstract: 白念珠菌((Candida albicans)获得铁的能力影响细胞的生长和毒力,高铁还原酶是白念珠菌高亲和铁吸收系统的重要组成部分.目的]构建高铁还原酶FRP1(Ferric reductase protein)基因缺失突变株,对FRP1基因功能进行初步研究.方法]使用Northem杂交的方法分析FRP1基因在缺铁和富铁条件下的表达.利用PCR介导的基因敲除技术构建frp1缺失突变株,并且对野生型和缺失突变株在细胞高铁还原酶活性以及缺铁条件下的生长情况进行比较分析.结果]缺铁条件可以诱导FRP1基因的表达.frp1缺失突变株不能在铁缺陷的固体培养基上生长.结论]FRP1蛋白可能是白念珠菌在缺铁条件下起主要作用的高铁还原酶.
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