朱砂叶螨对甲氰菊酯、阿维菌素,哒螨灵及其混剂抗性遗传力的分析(英文)

采用域性状分析法 ,估算了朱砂叶螨对 5种杀螨剂 (3种单剂和 2种混剂 )的抗性现实遗传力 ,并对 5种药剂的抗性风险进行了评估。把采自重庆北碚田间的朱砂叶螨种群 ,在室内不施药情况下饲养 6 0余代 ,以此作为抗性筛选的敏感品系。分别单一连续汰选近 30代 ,朱砂叶螨对甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)的抗性分别达 6 5 5 5、5 82、1 2 3、5 2 0和 1 4 2 倍 ;抗性现实遗传力分别为 0 2 16 7、0 0 96 7、0 0 130、0 0 80 0和 0 0 172。在实验室选择条件下 ,预计抗性增长 10倍时 ,甲氰菊酯、阿维菌素、哒螨灵、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)和甲氰 -阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)分别需要 15、34、333、4 2和 2 0 0代。甲氰菊酯抗性风险较高 ,其次是阿维菌素、哒螨 -阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)、甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m) ,哒螨灵抗性风险较低。混剂哒螨 阿维 (哒螨灵 :阿维菌素 =7 4 :0 1,m m)不能延缓朱砂叶螨对两单剂哒螨灵和阿维菌素的抗性发展 ,而混剂甲氰 阿维 (甲氰菊酯 :阿维菌素 =8 9:0 1,m m)却能有效延缓朱砂叶螨对两单剂     

朱砂叶螨对甲氨菊酯、阿维菌素，哒螨灵及其混剂抗性遗传力的分析

采用域性状分析法,估算了朱砂叶螨对5种杀螨剂(3种单剂和2种混剂)的抗性现实遗传力,并对5种药剂的抗性风险进行了评估。把采自重庆北碚田间的朱砂叶螨种群,在室内不施药情况下饲养60余代,以此作为抗性筛选的敏感品系。分别单一连续汰选近30代,朱砂叶螨对甲氰菊酯、阿维菌素、哒螨灵、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)和甲氰—阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)的抗性分别达65．55、5．82、1．23、5．20和1．42．倍;抗性现实遗传力分别为0．2167、0．0967、0．0130、0．0800和0．0172。在实验室选择条件下,预计抗性增长10倍时,甲氰菊酯、阿维菌素、哒螨灵、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)和甲氰—阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)分别需要15、34、333、42和200代。甲氰菊酯抗性风险较高,其余是阿维菌素、哒螨—阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)、甲氰-阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m),哒螨灵抗性风险较低。混剂哒螨-阿维(哒螨灵：阿维菌素＝7．4：0．1,m/m)不能延缓朱砂叶螨对两单剂哒螨灵和阿维菌素的抗性发展,而混剂甲氰-阿维(甲氰菊酯：阿维菌素＝8．9：0．1,m/m)却能有效延缓朱砂叶螨对两单剂甲氰菊酯和阿维菌素的抗性发展。     

甲氰菊酯与阿维菌素单用、轮用和混用对朱砂叶螨抗性进化的影响

应用数量遗传学的方法分析朱砂叶螨(Tetranychus cinnabarinus)实验种群对甲氰菊酯、阿维菌素及其混剂甲氰—阿维(甲氰菊酯:阿维菌素=8.9:0.1,m/m)的抗性现实遗传力,并测定了甲氰菊酯、阿维菌素分别连续单用、轮换使用、混合使用对朱砂叶螨抗性进化的影响。结果表明,筛选16代后,朱砂叶螨对甲氰菊酯、阿维菌素和甲氰—阿维的抗性现实遗传力分别为0.2853、0.1695和0.0804,朱砂叶螨对混剂的抗性现实遗传力低于对2个单剂的遗传力的一半,混用延缓抗性的效果将好于轮用。药剂连续单用、轮换使用和混合使用16代,朱砂叶螨对甲氰菊酯的抗性分别为28.52、28.03和10.81倍,对阿维菌素的抗性分别为3.24、2.82和1.41倍。朱砂叶螨对2种杀螨剂抗性进化速率为单用>轮用>混用,抗性测定结果表明甲氰菊酯与阿维菌素混用能有效延缓朱砂叶螨对2种药剂抗性的发展速率。     

甲氰菊酯与阿维菌素的混剂防治美洲斑潜蝇田间试验

田间试验表明 ,1 9%甲氰·阿维EC 9 5g (a .i.) 667m2 对美洲斑潜蝇LiriomyzasativaeBlanchard的校正防效药后 3～ 1 1d为 87 2 2 %～ 91 3 2 % ;7 1 2 5g (a.i.) 667m2 药后 3～ 1 1d为 81 2 9%～ 85 1 0 % ;9 5g (a .i.) 667m2 药后 3～ 1 1d防效显著优于单剂甲氰菊酯 ,药后 3～ 7d显著优于单剂阿维菌素 ,药后11d防效与阿维菌素无显著区别。 1 5 %甲氰·阿维EC 7 5g (a .i.) 667m2 对美洲斑潜蝇的校正防效药后3～ 1 1d为 85 5 9%～ 89 0 9% ;5 62 5g (a .i.) 667m2 药后 3～ 1 1d为 77 1 5 %～ 85 95 %。 1 0 %甲氰·阿维EC 7 5g (a .i.) 667m2 对美洲斑潜蝇的校正防效药后 3～ 1 1d为 85 5 9%～ 89 0 9% ;5 62 5g (a .i.) 667m2 药后 3～ 1 1d为 77 1 5 %～ 85 95 %。混剂的药效基本随有效成分含量的提高而提高。     

甲维盐·毒死蜱及其复配对小菜蛾的毒力分析

以小菜蛾（Plutella xylostellar） 3龄幼虫为试虫测定了甲胺基阿维菌素苯甲酸盐、毒死蜱及两者5种不同配比的复配剂的毒力,测定结果建立了“时间-剂量-死亡率”模型.根据模型分析结果,甲胺基阿维菌素苯甲酸盐与毒死蜱混配后增效显著.在5种配比中以甲氨基阿维菌素苯甲酸盐∶毒死蜱 =1∶ 74为最佳配比,其24-60 h 4个时段的共毒系数在334到550之间;与单剂相比,该配比明显提高了24 h时段内和48-60 h时段的杀虫率.     

鳖的形态学统计分析

利用生物统计学的方法对鳖的形态进行了分析 ,结果如下 :鳖的年龄 (Y)与体重 (X)的一元回归方程为 :Y =0 0 0 736 1X 0 4 534,年龄 (Y)与腹甲长 (X)的一元回归方程为 :Y =0 2 4 59X- 0 5480 ;雌雄鳖尾长差异显著 (P <0 0 5) ,雄鳖体重 (Y)对尾长 (X)的一元回归方程为 :Y =2 56 6 4X - 82 8 6 0 ;野生鳖体重 (Y)对背甲长 (X1)、体高 (X5)、头长 (X8)、眼径 (X9)、口裂 (X12 )等 13个形态学指标的最优多元回归方程为 :Y =880 51 6 79 16X1- 10 6 0 91X5 146 4 72X8- 82 96 6 4X9- 3142 0 9X12 ;控温条件下快速生长鳖体重 (Y)对腹甲宽 (X4 )、体高 (X5)、头发 (X8)、眼间距(X10 )、尾长 (X13)等 13个形态学指标的最优多元回归方程为 :Y =- 97 4 6 38 99X4 30 2 6X5-2 9 34X8 140 83X10 - 30 4 2X13.     

氟雷拉纳与三种杀虫剂对灰飞虱的 室内毒力及其联合作用

采用点滴法,测定了氟雷拉纳与毒死蜱、吡虫啉、甲氨基阿维菌素苯甲酸盐(简称甲维盐)单剂及其混剂对灰飞虱雌成虫的毒力,并通过共毒系数法评价复配药剂的联合作用。结果表明,氟雷拉纳和甲维盐对灰飞虱的毒力高,药后96 h,其LD_(50)值分别为0.382和0.201 ng/头;毒死蜱和吡虫啉对试虫的毒力低于氟雷拉纳和甲维盐,其LD_(50)值分别为1.127和1.016 ng/头。此外,氟雷拉纳与毒死蜱混配时表现出良好的增效作用,且配比为3∶2时,共毒系数最高为142;氟雷拉纳与甲维盐混配时,对灰飞虱的增效作用不显著,在配比为4∶1时,共毒系数仅为129;而氟雷拉纳与吡虫啉混配,当配比为2∶3和3∶2时对灰飞虱表现为拮抗作用,但配比为1∶4时表现为增效。以上结果说明,氟雷拉纳与毒死蜱复配对灰飞虱具有增效作用,可为研发田间有效防控该害虫的药剂组合提供科学依据。     

不同施肥处理对芳樟叶精油及其主成分芳樟醇含量的影响

为探讨不同施肥处理对芳樟(Cinnamomum camphora var.linaloolifera Fujita.)叶精油及其主成分芳樟醇含量的影响,运用三元二次回归正交旋转组合设计检测了不同N、P和K施肥条件下芳樟1年生扦插苗叶精油的含量和芳樟醇的相对含量并建立数学模型;通过对数学模型拟合的回归方程进行最优求解,确定最优施肥配比.结果表明:不同施肥处理对芳樟叶精油及芳樟醇相对含量的影响极显著,精油质量分数为1.53％ ～ 2.30％、芳樟醇相对含量为88.36％ ～ 94.87％.显著性分析结果显示:N和K施用量对精油含量分别有极显著和显著影响,N施用量对芳樟醇相对含量有显著影响而K施用量无显著影响,P施用量对精油含量和芳樟醇相对含量均无显著影响.N、P和K施用量与精油含量和芳樟醇相对含量数学模型的回归方程分别为Y=1.054+0.392X1-0.037X2 +0.280X3+0.014X1X2-0.022X1X3+ 0.018X2X3-0.057X12+0.001X22-0.053X32和Y=87.206 +2.802X1-0.279X2+ 1.115X3+0.180X1X2-0.147X1X3 +0.396X2 X3-0.525X12-0.137X22-0.275X32;据此计算出最优精油含量为2.22％,对应的N、P和K的每盆施用量分别为3.52、5.00和2.76 g;最优芳樟醇相对含量为95.18％,对应的N、P和K的每盆施用量分别为2.84、5.00和4.87 g.研究结果显示:N施用量对芳樟叶精油含量和芳樟醇相对含量的影响最大,最优精油含量和最优芳樟醇相对含量对应的施肥配比不完全相同,在生产中应根据生产目的并综合考虑各种环境因素确定合适的N、P和K施肥配比.     

中华草龟(♀)与中华花龟(♂)及其杂种F_1代形态性状对体重的影响效果分析

选择中华草龟、中华花龟及其杂种F1代幼龟共270只,测定了体重、背甲长、背甲宽、壳高、腹甲长等17个形态性状,采用相关分析、通径分析和多元回归分析研究了形态性状对体重的影响效果。结果表明,3种龟的测量形态性状与体重的相关系数均达到极显著水平(P0.01);通径分析显示背甲长、背甲宽、壳高、腹甲长和甲桥长对体重的通径系数达到显著水平,它们是直接影响体重的重要性状,其中背甲长和壳高是影响体重的共同性状;决定系数分析结果与通径分析结果有一致的变化趋势;所选形态性状与体重的复相关指数分别为R2=0.945、0.920和0.958,表明影响体重的主要自变量指标已经找到;利用逐步回归分析方法建立了以背甲长、壳高和腹甲长,背甲长、壳高和甲桥长,背甲长、背甲宽和壳高等3种龟的多元回归方程,分别为:Y=-156.764+9.895X1+17.449X3+14.347X4,Y=-295.040+13.443X1+40.603X3+38.632X9,Y=-280.960+14.908X1+14.290X2+43.129X3。     

响应面法优化枯草芽孢杆菌NHS1产芽孢发酵培养

为提高枯草芽孢杆菌(Bacillus subtilis)NHS1菌株发酵液中芽孢含量,采用单因素试验与响应曲面法优化试验相结合的方式,对该菌发酵培养基中的碳源、氮源以及无机盐等组成成分进行了优化。通过单因素试验、Plackett-Burman试验、最陡爬坡试验以及BoxBchnken试验构建响应方程,得到方程为:Y=-3.30+3.853X1+0.0928X2+0.623X3-0.913X1×X1-0.00704X2×X2-0.0433X3×X3-0.0033X1×X2-0.0700X1×X3+0.00167X2×X3。利用该方程预测得到最优培养基:淀粉1.88 g·L~(-1)、Na Cl 6.83 g·L~(-1)、玉米粉5.60 g·L~(-1),酵母粉10g·L~(-1),蛋白胨10 g·L~(-1),牛肉膏15 g·L~(-1),葡萄糖2 g·L~(-1),Mg SO43 g·L~(-1)。利用优化培养基,在36℃、170 r·min~(-1)条件下摇瓶发酵72 h,芽孢数达到2.42×109cfu·m L~(-1),比优化前提高1.5倍。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.