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Search Results: 1 - 10 of 66312 matches for " FENG Ming-Guang "
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Development of Zoophthora anhuiensis induced epizootic in Myzus persicae colonies and an analytical model to describe its trend

FENG Ming-Guang,

生态学报 , 2001,
Abstract: 在15℃与100%RH的组合条件下以接种安徽虫瘟霉(Zoophthora anhuiensis)和未接种的桃蚜(Myzus persicae)成蚜按不同比例混合(0:6,1:5,2:4,3:3,4:2,5:1及6:0)建立蚜群,3次重复,考察流行病的发生与发展,结果表明,在带菌蚜50%以上的蚜群中,活蚜的数量增长因高强度的流行病发生而得到有效控制,活蚜数妈终未超过50头/90cm^2,第22天观察结束时与对照(0:6)jah vtk r 656udi /90cm^2相比控蚜效果高达93.24%-100%,在接菌与未接菌比例1:5和2:4的蚜群中,蚜病的发生虽未能充分控制蚜虫的数量增长,但结束时的蚜虫数量均显著低于对照,分别为356头/90cm^2和207头/90cm^2,控蚜效果亦分别达46%和68%,各处理蚜群中病害流行随时间的变化很好地拟合Gompertz模型(r^2=0.97),由此估计出虫瘟霉不同初始菌量在蚜群中的流行速度(R)及最高流行水平(K),线性回归分析表明,初始侵染体密度确定了R(r^2=0.89)和K(r^2=0.90)估计值的90%变异,充分显示安徽虫瘟霉流行病的发生及流行强度对初始侵染体和寄主密度的依赖性。
Systematic validation of predicted microRNAs for cyclin D1
Qiong Jiang, Ming-Guang Feng, Yin-Yuan Mo
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-194
Abstract: In this study, we used luciferease reporter assays to validate microRNAs that can silence cyclin D1 (CCND1) because CCND1 is a well known proto-oncogene implicated in a variety of types of cancers. We chose miRanda http://www.microRNA.org webcite as a primary prediction method. We then cloned 51 of 58 predicted microRNA precursors into pCDH-CMV-MCS-EF1-copGFP and tested for their effect on the luciferase reporter carrying the 3'-untranslated region (UTR) of CCND1 gene.Real-time PCR revealed the 45 of 51 cloned microRNA precursors expressed a relatively high level of the exogenous microRNAs which were used in our validation experiments. By an arbitrary cutoff of 35% reduction, we identified 7 microRNAs that were able to suppress Luc-CCND1-UTR activity. Among them, 4 of them were previously validated targets and the rest 3 microRNAs were validated to be positive in this study. Of interest, we found that miR-503 not only suppressed the luciferase activity, but also suppressed the endogenous CCND1 both at protein and mRNA levels. Furthermore, we showed that miR-503 was able to reduce S phase cell populations and caused cell growth inhibition, suggesting that miR-503 may be a putative tumor suppressor.This study provides a more comprehensive picture of microRNA/CCND1 interactions and it further demonstrates the importance of experimental target validation.Accumulating evidence indicates that microRNAs could play a fundamental role in regulation of diverse cellular pathways including differentiation, proliferation and apoptosis [1,2]. Thus, deregulation of microRNAs affects normal cell growth and development, leading to a variety of disorders including human malignancies, which have been demonstrated in both in vitro and in vivo systems [1,3-6]. Importantly, tumor cells often express a unique set of microRNAs (or microRNA signature). For example, the overall microRNA expression profile of normal tissues is distinct from that of tumor tissues [7] and moreover, microRNA sig
Additive Contributions of Two Manganese-Cored Superoxide Dismutases (MnSODs) to Antioxidation, UV Tolerance and Virulence of Beauveria bassiana
Xue-Qin Xie,Fang Li,Sheng-Hua Ying,Ming-Guang Feng
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030298
Abstract: The biocontrol potential of entomopathogenic fungi against arthropod pests depends on not only their virulence to target pests but tolerance to outdoor high temperature and solar UV irradiation. Two Beauveria bassiana superoxide dismutases (SODs), BbSod2 and BbSod3, were characterized as cytosolic and mitochondrial manganese-cored isoenzymes (MnSODs) dominating the total SOD activity of the fungal entomopathogen under normal growth conditions. To probe their effects on the biocontrol potential of B. bassiana, ΔBbSod2, ΔBbSod3, and three hairpin RNA-interfered (RNAi) mutants with the transcripts of both BbSod2 and BbSod3 being suppressed by 91–97% were constructed and assayed for various phenotypic parameters in conjunction with ΔBbSod2/BbSod2, ΔBbSod3/BbSod3 and wild-type (control strains). In normal cultures, the knockout and RNAi mutants showed significant phenotypic alterations, including delayed sporulation, reduced conidial yields, and impaired conidial quality, but little change in colony morphology. Their mycelia or conidia became much more sensitive to menadione or H2O2-induced oxidative stress but had little change in sensitivity to the hyperosmolarity of NaCl and the high temperature of 45°C. Accompanied with the decreased antioxidative capability, conidial tolerances to UV-A and UV-B irradiations were reduced by 16.8% and 45.4% for ΔBbSod2, 18.7% and 44.7% for ΔBbSod3, and ~33.7% and ~63.8% for the RNAi mutants, respectively. Their median lethal times (LT50s) against Myzus persicae apterae, which were topically inoculated under a standardized spray, were delayed by 18.8%, 14.5% and 37.1%, respectively. Remarkably, the effects of cytosolic BbSod2 and mitochondrial BbSod3 on the phenotypic parameters important for the fungal bioncontrol potential were additive, well in accordance with the decreased SOD activities and the increased superoxide levels in the knockout and RNAi mutants. Our findings highlight for the first time that the two MnSODs co-contribute to the biocontrol potential of B. bassiana by mediating cellular antioxidative response.
Comparative susceptibility of Myzus persicae to 16 strains of Metarhizium spp. from different host insects and geographic regions

SHAN Le-tian,FENG Ming-guang,

微生物学报 , 2006,
Abstract: 害虫生防真菌绿僵菌的不同种及变种被广泛应用于害虫微生物防治,但罕见以蚜虫等同翅目刺吸式害虫作为靶标。从两种绿僵菌的4个变种中精选16个不同寄主及地理来源的菌株,用喷塔接种桃蚜(Myzus persicae)无翅成蚜并在25±1℃和12L∶12D条件下饲养观察,所获生物测定数据进行时间-剂量-死亡率模型模拟分析。结果显示,高接种剂量(~1000个孢子/mm2)下7d内死亡率达67%~100%的10个菌株均为金龟子绿僵菌Metarhiziumanisopliae(Ma)及其金龟子变种M.anisopliaevar.anisopliae(Maa);而高剂量处理下仅感染致死个别或少数蚜虫的菌株包括金龟子绿僵菌及其金龟子变种、大孢变种M.anisopliaevar.majus和蝗变种M.anisopliaevar.acridum以及黄绿绿僵菌小孢变种M.flavoviridevar.minus。杀蚜活性优异的2个菌株分别为Ma 456和Maa 3332,接种后第4天的LC50分别为113和260个孢子/mm2,第5天为32和43个孢子/mm2,第6天为17和26个孢子/mm2,第7天仅11.4和19.9个孢子/mm2。这两个菌株具有用于蚜虫微生物防治的良好开发潜力。
Intraspecific variations of Paecilomyces fumosoroseus in temperature fitness and carbendazim resistance.

ZHENG Wu,FENG Ming-guang,

应用生态学报 , 2007,
Abstract: A total of six wild strains of fungal biocontrol agent Paecilomyces fumosoroseus were grown at 15 degrees C-35 degrees C to reveal their variations in colony growth, conidiation, and conidial viability. The results showed that the test three indices were the best at 25 degrees C, but differed significantly at different temperatures for a given strain or at a given temperature among test strains. The strains Pfr116 and Pfr6206 behaved better or more stably than other strains at 15 degrees C-35 degrees C. The sensitivities of the fungal strains to gradient concentrations of fungicide carbendazim were assayed at the optimal temperature, based on their colony growth diameters and the counts of colony forming units (CFU). The inhibitory effect of carbendazim concentration on CFU counts fitted well to a Logistic model, with high coefficients of determination being achieved for all the strains (r2 > or = 0.90). The fitted minimal inhibitory concentration (MIC) values showed a low carbendazim resistance of strains Pfr4205 and Pfr116 (MIC < or = 20.0 microg x ml(-1)), whereas the other four strains fell within medium resistance to the fungicide (20 < or = MIC < or = 100). The MIC of strain Pfr6206 (93.5 microg x ml(-1) was very close to the high resistance level of MIC > 100 microg x ml(-1). Therefore, strain Pfr6206 was satisfactory with both the temperature fitness and the carbendazim resistance, and could be considered as a candidate strain for a fungal formulation adapting to more variable crop systems against insect pests.
Optimized solid-state fermentation of Aspergillus niger for production of feed-purpose β-glucanase and xylanase using rice residues from mass production of fungal biocontrol agents

WANG Xiao-xiao,FENG Ming-guang,

浙江大学学报(农业与生命科学版) , 2009,
Abstract: 为资源化利用生防真菌高纯度孢子粉在生产过程中产生的大量废米,将废米粉按比例混入麦麸作为基础物料,接种黑曲霉固相发酵生产饲用β-葡聚糖酶和木聚糖酶,得到麸米比7∶3的最佳配料;纯麦麸发酵3 d后2种酶的产量为353.8、343.8U·g-1干曲.在对发酵时间、配料含水量、补充氮源、微量元素、拌料水的表面活性剂浓度及pH值等单因素分别优化试验的基础上,选取对产酶影响较大的金属离子类型、硫酸铵添加量、拌料水的吐温80浓度和pH进行4因素3水平9处理的正交试验,获得的最优组合为麸米比7∶3的配料中加入0.1%KH2PO4和1% (NH4)2SO4,拌料水为0.3%吐温80和pH 5.经3次重复试验验证,用最优组合配料接种后在25 ℃下发酵54h,β-葡聚糖酶和木聚糖酶产量(±SD)分别达到(716.1±9.2)、(453.0±62.5)U·g-1干曲,远高于优化前相同麸米比配料的酶产量.这一结果为建立环境友好型真菌杀虫剂生产线提供了有用的配套技术,使饲用酶制剂生产节约麦麸30%.
Bioassay of conidial thermotolerance of Beauveria bassiana strains from different hosts and geographic origins

LI Hong-wen,FENG Ming-guang,

浙江大学学报(农业与生命科学版) , 2008,
Abstract: 为筛选获得适应我国南方夏季高温的生防菌株,将不同寄主和产地的12株球孢白僵菌(Beauveria bassiana)分生孢子分别悬浮于1mL萌发液中,接受48℃恒温水浴的热胁迫.以逻辑斯蒂方程拟合孢子萌发率随热胁迫时间的衰变过程,将孢子活力丧失一半所需的时间(LT50)作为各菌株对热胁迫反应的特征指标.结果表明,对所有测试的球孢白僵菌株,孢子的残存指数均随胁迫时间延长而降低,且供试菌株之间差异显著.所测菌株孢子的LT50平均值为12.6min(6·7~21·2min),仅1株的LT50高于20min,有4株的LT50低于10min.由此建立的技术体系可用于客观评价各种生防真菌的孢子耐热力.
Statistical features and grouping of alfalfa mosaic virus particles

CHEN Ji-shuang,FENG Ming-guang,

浙江大学学报(农业与生命科学版) , 2000,
Abstract: 以一株来自于白车根草 (Trifolium repens L.)上的苜蓿花叶病毒分离物 AMV- SY为材料 ,在电镜下观察测量经醋酸铀负染的 196个提纯病毒粒子 ,按其长度分成等距离的 5个组 ,用统计分析方法确定组间的差异 .所得各组粒子的平均大小依次是组 :(2 0 .4± 2 .5) nm× (18.7± 2 .3) nm,组 :(2 8.0± 2 .4 ) nm× (18.1± 2 .1) nm,组 :(36 .0± 2 .4 ) nm× (17.2± 2 .0 ) nm,组 :(4 4 .8± 2 .7)nm× (16 .9± 2 .0 ) nm,组 :(52 .0± 3.0 ) nm× (17.4± 1.0 ) nm.它们分别相当于前人根据 X-射线衍射或核磁共振所测定的 Ta- t,Ta- b,Tb,M和 B型病毒粒子 .方差分析表明 ,5组病毒粒子间长度差异极显著 ,即组 <组 <组 <组 <组 ;病毒粒子宽度差异也极显著 ,但仅组 粒子的宽度明显大于组 和组 ,说明在没有病毒 RNA参与的情况下 ,单由不含病毒 RNA的外壳蛋白亚基所构成的粒子其横向结构较为松散 .对 AMV统计分析的结果与前人根据对病毒粒子结晶中典型的粒子进行 X射线衍射分析或计算机模拟所获得的结果基本吻合 ,但组 粒子 ,即最长一组 AMV病毒粒子的统计长度明显小于结晶中 X-射线衍射分析所测得最长的 B型粒子

LI Hin-Ping,FENG Ming-Guang,

菌物学报 , 2000,
Abstract: 在不同温度(10~30℃)与光照(连续光照和连续黑暗)组合条件下进行了安徽虫瘟霉(Zoophthoraanhuiensis)离体产孢格局的研究.结果表明,适于安徽虫瘟霉产孢的温度为10~20℃,但以15℃最适,不仅产孢快和产孢量大,而且不受光照的影响.在25℃下虽能产孢,但产孢量大幅减少,30℃下则不产孢,25℃可能是安徽虫瘟霉产孢的高温极限.全光照各温度处理的产孢量总是比全黑暗相应温度处理的产孢量高,说明光照对产孢具有刺激作用.在10℃和全光照的组合中,累计产孢量最高且持续产孢时间最长,而相同温度与全黑暗处理的产孢量却很低,显示光照在偏低温度下是影响安徽虫瘟霉产孢的关键因素.概而言之,光照主要影响安徽虫瘟霉的产孢量,而温度主要影响其产孢速率或进程.

XU Jun-Huan,FENG Ming-Guang,

菌物学报 , 2001,
Abstract: A fluorescence microscopy on a basis of fluorescein diacetate and propidium iodide was used to investigate the persistence of primary conidia of Pandora delphacis (Entomophthorales) at combinated regimes of temperature (10~30℃) and relative humidity (51~100% RH). Examination of the conidia on glass coverslips sampled 24 h after discharge resulted in a survival rate of 42~81% at 51% RH, 69~89% at 74% RH, 70~95% at 85% RH, 67~100% at 90% RH, 76~100% at 95% RH, and 56~100% at 100% RH, respectively, varying with different temperature. Maintained at 10~30℃ for 4 mon, the rate of survial conidia remained 55~74% at 51%RH, 52~87% at 74% RH, 38~73% at 85% RH, and 1~65% at 90% RH, respectively. However, 7 d after discharge, few conidia were found surviving at 95% RH regardless of the temperature. The results indicate that the first 24 h after discharge was crucial to longer survival of P. delphacis conidia at the humidity of 74% RH whereas saturated or nearly saturated air was not favorable to their longer survival.
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