大气CO2不同浓度对灰飞虱获毒与传毒的影响研究

本世纪初,由灰飞虱Laodelphax striatellus传播的条纹病毒(RSV)引起的条纹叶枯病在长江中下游广大稻区肆虐,给这些地区的水稻生产带来了灾难性影响。本文采用模拟气室法,研究了大气CO_23个浓度(370μL/L(CK)、470μL/L和570μL/L)对媒介害虫灰飞虱获毒与传毒的影响。结果表明,灰飞虱获毒个体数与灰飞虱的取食时间成正比,在有毒稻株上取食时间越长,获毒的灰飞虱个体数越多。不同CO_2浓度间,取食相同时间后的灰飞虱获毒个体数虽有差异,但没有达到显著水平。鉴于稻株获得RSV与病毒病的症状显现之间存在较长的时间差,本文通过提取水稻植株体内的RNA并借助RT-PCR技术,研究判定被害稻株是否已经获得了RSV,从而间接证明灰飞虱的传毒力。研究结果显示,CO_2浓度对灰飞虱的传毒力有影响:470μL/L CO_2浓度条件下灰飞虱的传毒力最强。研究还发现,在处理的3个CO_2浓度范围内,灰飞虱只要取食为害稻苗1 h,水稻中就能检测到条纹病毒(RSV)。说明灰飞虱的传毒速率还是较快的。     

灰飞虱体内类酵母共生菌异常毕赤酵母的分离培养及其对杀菌剂的敏感性

【目的】随着杀虫剂等化学农药的大规模使用,灰飞虱Laodelphax striatellus的抗药性不断增强,防治效果下降,因此寻找新的防治方法尤为重要。本研究探索使用杀菌剂来减少灰飞虱体内共生菌的数量,以降低灰飞虱的活力,为"抑菌防虫"提供理论依据。【方法】对灰飞虱体内的类酵母共生菌(yeast-like symbiotes,YLS)进行离体培养并鉴定,测定离体培养YLS对不同浓度不同种类杀菌剂的敏感性,将对其抑制作用明显的杀菌剂喷施于麦苗,待灰飞虱取食后统计灰飞虱死亡率、体重,并通过荧光定量PCR检测体内共生菌的数量变化。【结果】离体培养得到1株YLS,经碳源同化实验和18S r DNA分子鉴定,将该菌株归为异常毕赤酵母Pichia anomala,以变性梯度凝胶电泳(denatured gradient gel electrophoresis,DGGE)技术验证了该菌株在灰飞虱体内的存在。对杀菌剂敏感性的测定结果显示,70%丙森锌和50%戊唑醇+25%肟菌酯对P.anomala抑制效果明显,而氟吡菌胺+霜霉威盐酸盐(687.5 g a.i./L)与40%嘧霉胺对P.anomala的抑制效果较差。用对P.anomala抑制效果明显的两种杀菌剂(70%丙森锌和50%戊唑醇+25%肟菌酯)以800 mg/L浓度喷施麦苗,灰飞虱取食喷施麦苗后的死亡率分别达到46.7%与63.3%,显著高于对照,而体重比对照组显著低。荧光定量检测结果表明,灰飞虱体内3种共生菌(Noda菌、季也蒙毕赤酵母和异常毕赤酵母)的数量在使用了各种杀菌剂后均显著降低。【结论】结果说明,体外喷施杀菌剂对灰飞虱体内共生菌有抑制作用,进而对灰飞虱的生长存活产生影响,这为杀菌剂与杀虫剂的协同使用防治灰飞虱奠定基础。     

灰飞虱取食行为刺吸电位波形的初步研究

利用刺吸电位技术(EPG)研究了灰飞虱Laodelphax striatellus(Fallén)EPG波形与其取食行为之间的对应关系,并对不同虫龄、性别灰飞虱的取食行为进行EPG特征参数的比较。结果表明,灰飞虱取食行为的EPG波形可分为NP、N1、N2-a、N2-b、N3、N4和N5 7种类型,波谱的形状和频率与已报道的褐飞虱Nilaparvata lugens(Stl)的EPG取食波形基本相同。首次发现灰飞虱在口针刺探水稻维管束进行唾液分泌时可明显分为两个阶段即N2-a和N2-b。N2-a波表示口针移动并伴随唾液的分泌;N2-b波与灰飞虱持续分泌唾液的行为有关。经对比,不同虫龄、性别灰飞虱的EPG取食波形基本相同,但EPG特征参数存在差异。雌虫刺探次数显著多于雄虫和低龄若虫;成虫口针在临近韧皮部细胞外移动的时间显著长于若虫。     

水稻条纹叶枯病毒对灰飞虱生物学特性及若干生理生化特性的影响

【目的】为明确水稻条纹叶枯病毒(Rice stripe virus,RSV)侵染对灰飞虱Laodelphax striatellus(Fallén)生长发育的影响,本文比较研究了带毒与无毒灰飞虱发育历期及寿命、卵巢发育及体内相关酶活力等生物学特征和生理生化指标间的差异。【方法】利用单管饲养法,比较分析了带毒与无毒灰飞虱若虫历期与成虫寿命;通过解剖灰飞虱卵巢,观察并统计不同卵子级别与数量,研究携带RSV病毒对灰飞虱卵巢发育的影响;利用多种酶活力测定方法,比较带毒与无毒灰飞虱若虫期5种相关酶活力的差异。【结果】无毒灰飞虱雌、雄若虫历期分别为(16.30±0.33)d和(15.62±0.21)d;带毒灰飞虱雌、雄若虫历期分别为(19.08±0.43)d和(18.50±0.58)d,表明RSV侵染显著延缓了灰飞虱若虫的生长发育(t-test,P0.001);而无毒灰飞虱雌、雄成虫寿命分别为(10.74±0.81)d和(14.46±1.34)d;带毒灰飞虱雌、雄成虫寿命分别为(9.09±1.27)d和(13.55±2.38)d,表明RSV侵染对灰飞虱成虫发育没有显著影响。解剖羽化后的灰飞虱卵巢经统计分析后,发现RSV侵染后灰飞虱的卵巢发育及卵子发生并未受到明显影响。对发育至3龄若虫后12、24、120 h的无毒与带毒灰飞虱进行相关的酶活力测定,包括保护酶系超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT、解毒酶系谷胱甘肽-S转移酶GST和乙酰胆碱酯酶Ach E,发现RSV侵染对灰飞虱体内相关生化酶活力大小无明显影响,但可改变酶活力的变化趋势。【结论】RSV侵染显著延长灰飞虱若虫发育历期,但对成虫的寿命和卵巢发育无明显影响,对体内保护、解毒等相关代谢酶活力大小没有显著影响,但却可以改变酶活力的变化趋势,推测RSV与灰飞虱不存在典型的互惠互利关系。     

南方水稻黑条矮缩病对褐飞虱和白背飞虱体内三种保护酶活性的影响

为探寻植物感染病毒病后对刺吸性害虫体内生化酶活性的影响,本文研究了感染南方水稻矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)的水稻对褐飞虱Nilaparvata lugens和白背飞虱Sogatella furcifera成虫及若虫体内三种保护酶活性的影响。结果表明,取食染病水稻的白背飞虱和褐飞虱成虫及若虫体内超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和过氧化氢酶(catalase,CAT)的活性均随取食时间的延长而增加。在带毒水稻上取食12 h后,白背飞虱成虫、褐飞虱成虫、若虫体内SOD活性与对照比差异不显著外,其他均显著高于对照;取食24 h后,白背飞虱若虫体内SOD、POD活性和褐飞虱若虫SOD活性虽高于对照但未达显著水平;取食5 d后,白背飞虱若虫、褐飞虱成虫、若虫POD活性未达显著外,其他均显著高于对照。以上研究结果可为进一步研究植物-病毒-寄主三种之间的关系提供参考。     

Phylogenetic position of yeast-like symbiotes from three rice planthoppers (Homoptera: Delphacidae ) based on 18S rDNA and ITS-5.8S rDNA sequences

为研究水稻3种主要害虫灰飞虱Laodelphax striatellus、褐飞虱Nilaparvata lugens和白背飞虱Sogatella furcifera体内类酵母共生菌( yeast-like symbiotes,YLS)的种属地位及与寄主的进化关系,测定了其体内YIS的18SrDNA及ITS-5.8S rDNA的全长序列.基于3种稻飞虱体内YLS的18S rDNA序列比对表明,褐飞虱YLS和白背飞虱YLS的一致性比其与灰飞虱YLs的高(褐飞虱YLS和白背飞虱YLS为98.91％,灰飞虱YLS和褐飞虱YLS为95.74％,灰飞虱YLS和白背飞虱YLS为96.02％),而基于ITS-5.8S rDNA序列比对,灰飞虱YLS和白背飞虱YLS的一致性比其与褐飞虱YLS的要高(白背飞虱YLS和灰飞虱YLS为99.57％,灰飞虱YLS和褐飞虱YIS为91.91％,白背飞虱YLS和褐飞虱YLS为90.46％).基于真菌18S rDNA和ITS-5.8S rDNA的系统发育树均表明,3种稻飞虱体内YLS与其他已知真菌进化关系较远.本研究证实了昆虫真菌类共生菌与寄主形成了长期的进化关系,从而形成了不同于已知真菌的分类地位.     

灰飞虱胁迫对水稻叶片中防御酶活性及细胞超微结构的影响

为探讨灰飞虱为害对水稻叶片的防御酶及细胞结构的影响,利用透射电镜观察了灰飞虱取食不同时间后叶片细胞超微结构的变化并测定了防御酶的活性。灰飞虱为害后,透射电子显微镜观察显示,随着灰飞虱取食时间延长,感虫水稻‘Kittake’的叶片细胞逐渐出现质壁分离,叶绿体发育异常,结构趋于模糊,72h后叶绿体膜破裂,叶绿体基粒片层完全溶解或断裂;抗虫品种‘Mudgo’叶绿体结构完整,基粒及片层结构完好,抗虫水稻的厚壁组织细胞内聚集了大量电子致密物,细胞内结晶状物质可能为酚类化合物。抗感水稻植株体内的苯丙氨酸解氨酶（PAL）和过氧化物酶（POD）的活性随灰飞虱取食时间延长而显著升高,多酚氧化酶（PPO）活性则表现出先上升后下降的趋势,且‘Mudgo’中的3种防御酶活性明显高于‘Kit—take’的,表明3种酶的活性均受灰飞虱为害诱导升高,但‘Mudgo’中3种酶活性上升的速度和幅度均高于‘Kittake’。     

褐飞虱致害性变异过程及其体内酶的变化

在室内连续用具不同抗虫基因的水稻品种TNl、IR26、Mudg。和ASD7、单管饲养褐飞虱(Nilaparvata lugens)种群,研究它对抗虫水稻品种的适应过程及其体内酶的变化规律。 结果表明：褐飞虱在抗虫品种上取食2代的若虫存活率、若虫历期和短翅成虫体重均明显比取食感虫品种TNl的低,第3代以后与取食TNl者基本相同。第2代是褐飞虱适应抗虫品种的关键期。天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)和丁-谷氨酰基转移 酶(GGT)的活性在关键的第2代最低,而超氧物歧化酶(SOD)和过氧化氢酶(CAT)的含量增加。褐飞虱在适应抗虫品种以后体内天冬氨酸氨基转移酶活性明显提高。     

山东省不同地区灰飞虱对溴氰虫酰胺的敏感性及亚致死剂量溴氰虫酰胺对灰飞虱解毒酶活性的影响

为了探究山东不同地区灰飞虱种群对溴氰虫酰胺的敏感性水平差异,在室内采用稻苗浸渍法和点滴法分别测定了溴氰虫酰胺对泰安、莱芜、鱼台(分别采自小麦和水稻)、济南和济阳6个灰飞虱种群3龄若虫和成虫的毒力,同时测定了亚致死剂量(LD 10和LD 30)溴氰虫酰胺对灰飞虱成虫体内的酯酶(ESTs)、谷胱甘肽-S-转移酶(GSTs)和多功能氧化酶(MFO)活性的影响。稻苗浸渍法结果表明,溴氰虫酰胺对6个灰飞虱种群3龄若虫的LC 50值介于8.5193~11.0524 mg/L,对成虫的LC 50值介于10.4245~12.4904 mg/L。点滴法测定结果表明,溴氰虫酰胺对6个灰飞虱种群3龄若虫的LD 50值在0.9239×10-3~1.1318×10-3μg/头之间,对成虫的LD 50值在1.0933×10-3~1.2619×10-3μg/头之间。在溴氰虫酰胺亚致死剂量(LD 10和LD 30)处理下,灰飞虱体内3种解毒酶活性均被诱导上升,其中GSTs酶活力上升最显著。结果表明,山东不同地区田间灰飞虱种群对溴氰虫酰胺的敏感性差异不大,同一地区灰飞虱种群不同虫态对溴氰虫酰胺的敏感性也无明显差异。GSTs可能会在灰飞虱对溴氰虫酰胺后续抗性形成中起作用。     

褐飞虱与灰飞虱间接种内和种间效应的比较研究

为了明确褐飞虱Nilaparva talugens(Stl)与灰飞虱Laodelphgax striatellus(Fallén)经寄主植物而诱导引起的间接种间效应,在人工气候室内以健康植株为对照,研究了2种飞虱在事先分别经一种稻飞虱危害的汕优63和秀水11上的表现,比较由同种或异种诱导的间接种内和种间效应对该2种稻飞虱主要生物学参数的影响,结果表明在每2株稻苗接20头高龄单一种飞虱若虫危害2d的条件下,褐飞虱存在一定的间接种内竞争,主要表现为在事先由同种危害的寄主上若虫存活率显著下降,但未发现灰飞虱对褐飞虱的正面或负面的间接种间效应。但是,在试验条件下灰飞虱并不存在间接种内竞争,而存在着显著的褐飞虱对灰飞虱诱导的间接种间促进作用,主要表现为在事先经褐飞虱取食危害的寄主植物上灰飞虱若虫的历期缩短、存活率提高、雌成虫寿命延长、每雌产卵量增加。同时,褐飞虱对灰飞虱所表现的间接诱导种间促进效应与寄主品种有显著互作关系,在中抗灰飞虱的汕优63品种上,间接诱导种间促进效应较在感灰飞虱品种秀水10上更为明显。本文对稻飞虱间接诱导种内和种间效应的机制和进化意义进行了讨论。     

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.