温湿度对安徽虫瘟霉在桃蚜居群中流行的影响

用安徽虫瘟霉(Zoopphthoraanhuiensis)接种桃蚜(Myzuspersicae)无翅成蚜3头和健蚜3头组成新的蚜群若干,在不同温湿组合条件下任其繁殖、发病和传染,以评价温湿度对该菌在蚜群中流行的影响.持续26d观察,在偏低温与各湿度(90～100%RH)的组合中均成功诱发了蚜病流行,其程度受湿度影响较小.在10℃与各湿度组合中,最终感病死亡率为72.9%～98.2%,15℃下为78.7%～94.4%,流行强度极大.而20℃下仅100%RH诱发了高强度流行病,其余湿度下感病死亡率仅为5.1%～12.8%.在25℃,100%RH下死亡率仅27.2%.与所有湿度组合中的对照蚜群相比,10℃下流行病控蚜效果为89.5%～96.9%,15℃下为96.1%～98.2%,20℃下为45.9%～85.7%,25℃下为56.4%～69.7%.逐步回归分析表明,安徽虫瘟霉引发的蚜病流行与温度及其相对湿度和蚜群带菌后天数的互作项密切相关(r2=0.82,a＜0.01),这些变量在很大程度上决定了安徽虫瘟霉是否在蚜群中流行.     

安徽虫瘟霉菌株的强毒杀蚜效应与侵染速率*

报道安徽虫瘟霉（Zoophthoraanhuiensis）菌株F97028对挑蚜（Myzuspersicae）的强毒杀蚜活性。以7个孢子剂量（0．4～10．4个孢子／mm2）接种2～3龄若蚜（52～86头／剂量）,连续观察7d所获数据经时间－剂量－死亡率模型模拟分析,接种后第3～7d的LD50分别为34.8、8.7、1.5、0.7和0.4个孢子／mm2。在所用剂量范围内LT50为29～6.0d,随剂量增大而缩短。在接种后不同时段用0.1％百菌清水溶液处理被接种蚜体表面,结果显示,在15～20℃下,在0.7～1．8个孢子／mm2的剂量下接种后2h内的有效侵染率为42～58％,4h内为44％～74％,6h时达90％以上;在69～9．0个孢于／mm2的剂量下接种后1h,有效侵染率为57％～67％,2h内为77％～86％,4h内为78％～90％;高剂量（499～54．8个孢子／mm2）下接种后1h即达90％以上。与虫瘟霉属其它菌种或菌株对蚜虫的毒力比较,F97028菌株的毒力高28～117倍,为罕见的强毒杀蚜菌株。     

安徽虫瘟霉在侵染潜伏期内对桃蚜无翅成蚜生殖力的影响

在8个剂量（0．48－61．15个孢子.mm^-2)下测定安徽虫瘟霉F97029菌株对桃蚜（Myzus persicae (Sulzer))2-3龄若蚜（57－84头／剂量（的毒力,接种后第3－7d的半致死剂量LD50分别为3．09,.88,1.33,1.28,1.26个孢子／mm2,致死中时LT50为2－6d,随剂量增大而缩短,将该菌株按60个孢子.mm^-2的剂量接种桃蚜的无翅成蚜,在10,15,20,25℃下其侵染潜伏期分别为7．2,5．3,4．9,3．9d,温度与潜伏期呈显著负相关（r^2=0.94),在相同梯度温度下,接种成蚜在病害潜伏期内平均产若蚜7．97头,11．20头,11．86头和11．20头,与同期对照相比依次下降56．45％,41．58％,39．98％,49．02％,根据日观察数据建立接种后潜伏期内45．54％（15℃）,43．11％（20℃）,和50．84％（25℃）,内禀增长率（rm)比对照分别下降24．28％,16．98％,14．12％和20．13％,表明安徽虫瘟霉感染引发的真菌病害对桃蚜种群增长具有显著的抑制作用。     

飞虱虫疠霉杀蚜效果及开发应用前景

通过比较飞虱虫疠霉 (Pandoradelphacis)与其它几种常见蚜虫专化性病原真菌新蚜虫疠霉(P .neoaphidis)、安徽虫瘟霉 (Zoothphoraanhuiensis)和根虫瘟霉 (Z .radicans)对桃蚜 (Myzuspersicae)毒力 ,证实了该菌的杀蚜应用潜力。时间 -剂量 -死亡率模型分析表明 ,飞虱虫疠霉杀蚜的各项毒力指标与其它几种虫霉相似或略高 ,但杀蚜速率更快。同时对培养性状、产孢特性和生长适温等的比较研究发现 ,该菌具有易发酵生产、产孢能力强和温度生长范围宽等特点 ,是一种较为理想的有望研制开发成杀蚜真菌制剂的病原菌。此外 ,根据虫霉孢子主动弹射的生物学特性 ,提出了该菌的适用剂型 ,并对它们的流行学特性及其在设栽培中的应用前景进行了讨论。     

飞虱虫疠霉继发性感染对桃蚜数量增长的控制作用

用飞虱虫疠霉（Pandora delphaics)“孢子浴”接种的桃蚜(Myzus persicae)无翅成蚜在离体甘蓝菜叶片（65cm^2)上建立蚜群,在不同温度（10－30℃）和湿度（74％－100％RH）的组合条件下任其繁衍,发病和交互感染,以评价该菌的控蚜效果。在25个温,湿度组合处理（8次重复,每重复含3头接种成蚜)中,蚜群均不同程度的发病死亡,在历时30d的观察中,以高温（20－30℃）,高湿（95％RH）组合条件下的蚜群发病快且死亡率高,蚜尸上产生的孢子有效地引起若蚜继发性感染。与相同温度下不带菌的对照蚜群相比,次于30℃下,各湿度除个别例外,第8d的控蚜率达30％以上,第20d达80％以上。在10℃和15℃下,控蚜效果一般不如上述较高温度下,且与湿度的关联程度相对较低,但最大控蚜效果均发生在100％RH处理中。结果表明,飞虱虫疠霉用于蚜虫防治的潜力很大,值得深入研究和开发利用。     

稻纵卷叶螟根虫瘟霉的分离鉴定及其流行病研究

在广东省发现一种新的侵染稻纵卷叶螟幼虫的昆虫病原真菌,经鉴定该病原真菌为根虫瘟霉Zoophthora radicans,这是中国首次报道该菌侵染稻纵卷叶螟。在室内进行的温度和光周期对该菌生长的影响实验表明,该菌在15－25℃均可生长,最适生长温度为25℃;光周期对菌落生长影响不显著。根虫瘟霉主要侵染稻纵卷叶螟3－5龄幼虫,对3－5龄幼虫的侵染率分别为2.71%、24.32%和72.97%。在10－11月,根虫瘟霉可持续引发稻纵卷叶螟幼虫高强度流行病,侵染率高达95%。该菌以休眠孢子越冬,成为次年稻纵卷叶螟幼虫流行病的初侵染源。因此,根虫瘟霉是稻纵卷叶螟幼虫一种有效的自然控制因子。     

蓝光影响新蚜虫疠霉分生孢子弹射潜力的室内评估

新蚜虫疠霉Pandora neoaphidis是虫霉菌亚门Entomophthoromycotina虫霉目Entomophthorales的代表菌,是世界上流行最广的蚜科专化性病原真菌。其主动弹射分生孢子的能力是引发高强度流行病控制蚜虫种群的关键原因。本研究以新蚜虫疠霉菌丝制备的弹孢胶囊（模拟感病蚜尸）为研究对象,在室内对其在蓝光照射和黑暗条件下的产孢量和分生孢子弹射距离进行了测量;同时利用高速显微摄像技术对弹孢胶囊的分生孢子弹射进行了拍摄观察和软件视频分析,利用MATLAB软件分析图像视频并进行了模型构建。结果表明：新蚜虫疠霉菌丝胶囊经蓝光照射处理后弹射出来的分生孢子数量和孢子弹射速度均显著高于黑暗条件下的处理（P<0.05）;分析高速显微拍摄视频计算所得的孢子弹射初始速度从114mm/s到2.07m/s不等,速度在弹射后期会受到空气阻力的影响而急速下降;采用Stokes模型进行预测的结果显示其分生孢子的弹射路径与实际路径拟合度较高（R²=0.8941）。综上,本研究结果为深入理解新蚜虫疠霉弹射相关的流行扩散模型和生物学适态机制提供了基础数据。     

桃蚜虫霉病始发期的初始感染与接触传染

自2002年10月至2005年5月在杭州上空诱获桃蚜(Myzus persicae)的迁飞性有翅蚜2351头,将其带回室内在(21±1)℃和12L∶12D条件下单头饲养12d,其中639头在定殖后7d内发病死亡,初始感染率达27·2%。在病死有翅蚜中,99·4%系5种蚜科专化性虫霉侵染所致,新蚜虫疠霉(Pandora neoaphidis)的发生比例高达81·4%。带病迁飞的有翅蚜在发病死亡前具有一定生殖力,定殖后第6天平均累计产若蚜(2·4±0·13)头,远低于同期未带病有翅蚜产下的(11·6±0·33)头。在带病有翅蚜建立的后代蚜群中,接触传染在母蚜死亡2d后即可见到。在定殖后第12天,二级感染占总观察蚜群数的13·3%,三级感染占总观察蚜群数的4·4%,占二级感染蚜群数的33·3%。此时,未带病有翅蚜的后代蚜群的平均活蚜数达(50·6±2·30)头,而带病有翅蚜的后代蚜群平均仅有(21·5±1·98)头。结果表明,虫霉病能够通过寄主带病迁飞传至寄主迁入地,并在后代蚜群中相互传染而起到调节蚜虫数量增长的作用。     

麦蚜虫霉流行病的初始侵染源及传播途径观察

在河南省原阳县麦区于2002年4~5月期间自空中诱捕到迁飞性有翅麦蚜共1092头, 其中麦长管蚜(Sitobion avenae)415头, 禾谷缢管蚜(Rhopalosiphum padi)642头, 麦无网长管蚜(Metopolophium dirhodum)22头, 麦二叉蚜(Schizaphis graminum)13头. 每日诱获的有翅蚜带回室内在试管麦苗上单头饲养7 d, 共发病死亡341头(麦长管蚜224头, 禾谷缢管蚜106头, 麦二叉蚜3头, 麦无网长管蚜8头), 全部在饲养的前5天死亡, 其中前3天的死亡占78.9%, 有翅蚜的总带菌率为31.2%. 病死有翅蚜经逐头镜检确认病因, 全系虫霉感染所致, 其中新蚜虫疠霉(Pandora neoaphidis)占84.6%, 普朗肯虫霉(Entomophthora planchoniana)占5.5%, 暗孢耳霉(Conidiobolus obscurus)占9.9%, 另有4例为新蚜虫疠霉和暗孢耳霉的复合感染. 基于迁飞性有翅麦蚜高比例带菌和田间麦蚜虫霉流行病的调查资料, 可以认为麦蚜的虫霉流行病可能主要借有翅蚜的迁飞定殖而异地传播, 并讨论了这种传播方式对蚜虫流行病研究与利用的启示.     

福建厦门地区蚜虫病原真菌调查及其发生规律

从2014年至2015年对厦门地区蚜虫虫霉发生和流行情况进行初步调查,共鉴定出6种虫霉目病原真菌:新蚜虫疠霉Pandora neoaphidis、努利虫疠霉Pandora nouryi、普朗肯虫霉Entomophthora planchoniana、暗孢耳霉Conidiobolus obscurus、弗雷生新接霉Neozygites fresenii、根虫瘟霉Zoophthora radicans。新蚜虫疠霉和普朗肯虫霉是春季蔬菜蚜虫种群中发生、流行的最重要病原真菌,夏季未观察到虫霉的发生。     

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.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.