斯氏钝绥螨对西花蓟马的捕食功能反应

【目的】明确斯氏钝绥螨在不同温度下对西花蓟马的捕食功能反应,为西花蓟马的生物防治提供理论依据。【方法】室内采用水琼脂培养基法,研究斯氏钝绥螨对西花蓟马的捕食功能反应。【结果】斯氏钝绥螨第一若螨对西花蓟马1龄若虫的日均捕食量随温度的升高而逐渐增加,而第二若螨、雄成螨和雌成螨的日均捕食量随温度的上升呈先增加后减少的趋势。斯氏钝绥螨雌成螨对西花蓟马1龄若虫的功能反应符合Holling-Ⅱ模型,在30℃时捕食效能达到最大,为18.146。在一定密度的西花蓟马环境下,斯氏钝绥螨雌成螨对西花蓟马1龄若虫的搜寻效应随着温度的上升而增加; 35℃时,搜寻效应下降。在西花蓟马1龄若虫的密度为30头时,斯氏钝绥螨雌成螨自身密度对西花蓟马1龄若虫的捕食具有明显的干扰作用。斯氏钝绥螨雌成螨捕食西花蓟马1龄若虫所产生的竞争属于分摊竞争。【结论】斯氏钝绥螨对西花蓟马有较好的捕食能力,其捕食功能反应符合Holling-Ⅱ模型,斯氏钝绥螨可用于西花蓟马的生物防治中。     

微小花蝽对四种猎物的喜好性

【目的】了解微小花蝽Orius minutus(Linnaeus)对4种主要自然猎物的喜好性。【方法】通过非选择性和选择性试验,室内测定并比较了微小花蝽初孵若虫、刚蜕皮后的5龄若虫和新羽化雌成虫对朱砂叶螨Tetranychus cinnabarinus(Boisduval)成螨、桃蚜Myzus persicae(Sulzer)低龄若虫、西花蓟马Frankliniella occidentalis(Pergande)2龄若虫和烟粉虱Bemisia tabaci(Gennadius)2-3龄若虫的日捕食量和喜好性Ci值。【结果】非选择性试验结果表明,在4种供试猎物中,微小花蝽初孵若虫对西花蓟马2龄若虫和朱砂叶螨成螨的日捕食量为最大,分别为14.20头/d和12.40头/d,刚蜕皮后的5龄若虫和新羽化雌成虫对朱砂叶螨成螨的日捕食量均为最大,分别为44.40头/d和37.20头/d。选择性试验结果表明,微小花蝽初孵若虫对西花蓟马2龄若虫和朱砂叶螨成螨均表现为正喜好性,其喜好性Ci值无显著差异,刚蜕皮后的5龄若虫和新羽化雌成虫对西花蓟马2龄若虫和桃蚜低龄若虫均表现为正喜好性,2者对西花蓟马的喜好性Ci值均显著大于对桃蚜。【结论】微小花蝽日捕食量最大的猎物是朱砂叶螨,其次是西花蓟马,而其最喜好的猎物则是西花蓟马。     

斯氏钝绥螨对西花蓟马和豆大蓟马若虫的捕食功能反应

【目的】为明确斯氏钝绥螨Amblyseius swirskii对西花蓟马Frankliniella occidentalis和豆大蓟马Megalurothrips usitatus不同龄期若虫的捕食量及控制潜能。【方法】在25℃和75%相对湿度下,研究了斯氏钝绥螨雌成螨对两种蓟马1龄和2龄若虫的捕食喜好性、功能反应以及捕食螨自身的干扰反应。【结果】斯氏钝绥螨无论对西花蓟马还是豆大蓟马,在各自1龄和2龄若虫共存状况下,对1龄若虫的喜好性均显著高于2龄。捕食螨对两种蓟马1龄若虫的捕食量和喜好性无显著差异,但对西花蓟马2龄若虫的捕食量和喜好性显著大于豆大蓟马2龄若虫。斯氏钝绥螨雌成螨对西花蓟马和豆大蓟马的1龄若虫和2龄若虫的捕食功能反应均符合HollingⅡ型方程。捕食螨对西花蓟马和豆大蓟马1龄若虫的日均捕食量均随其自身密度的增加而逐渐降低。【结论】斯氏钝绥螨的捕食量与蓟马的种类和龄期有关,也与捕食螨的密度有关。     

东亚小花蝽对西方花蓟马和二斑叶螨的捕食选择性

多食性天敌对猎物的捕食选择性及猎物密度对天敌捕食的干扰作用直接影响到天敌对不同猎物的控制作用.在实验室条件下研究了东亚小花蝽对西方花蓟马和/或二斑叶螨不同虫态的捕食选择性,以及两猎物中一种猎物的密度变化对小花蝽取食另一种猎物的影响.结果如下:东亚小花蝽5龄若虫和成虫对西方花蓟马2龄若虫的捕食选择性均强于对其成虫,对二斑叶螨的选择性为雌成螨>若螨>幼螨.实验中西方花蓟马2龄若虫是东亚小花蝽最喜好的虫态.二斑叶螨雌成螨密度固定为60头/19.63cm2,西方花蓟马若虫密度从10增加到60时显著地减少了东亚小花蝽对二斑叶螨的取食.反之,固定西方花蓟马同样密度,增加二斑叶螨密度却没有显著改变小花蝽对西方花蓟马的取食.此结果进一步表明,西方花蓟马是东亚小花蝽更喜好的猎物.     

应用实验种群生命表评价巴氏新小绥螨对西花蓟马的控制能力

以西花蓟马Frankliniella occidentalis（Pergande）（Thysanoptera,Thripidae）一龄若虫为猎物组建巴氏新小绥螨Neoseiulus barkeri（Hughes）（Acari：Phytoseiidae）实验种群生命表,获得净生殖力Ro=27．37,世代平均历期T=22．17天,内禀增长率rm=0．15,周限增长率λ=1．16,种群倍增所需时间t=4．64天等参数。将获得参数值与西花蓟马的相关参数值进行比较,巴氏新小绥螨瞬间增长率大于西花蓟马的瞬间增长率（0．14）,雌成螨日取食7～12头西花蓟马一龄若虫,表明巴氏新小绥螨可以作为控制西花蓟马种群数量的有效天敌。     

西花蓟马、二斑叶螨与黄瓜新小绥螨的相互关系研究

西花蓟马Frankliniella occidentalis（Pergande）和二斑叶螨Tetranychus urticae Koch是温室花卉与蔬菜上的重要害虫（螨）。植物常被两者同时危害。黄瓜新小绥螨Amblyseius cucumeris（Oudemans）是世界上广泛应用的温室蓟马的生物防治物,有时也被用来防治二斑叶螨。本研究中,在人工气候室盆栽条件下利用黄瓜新小绥螨防治西花蓟马和/或二斑叶螨。结果显示,当每豆株上接入10或20头二斑叶螨时,按照1∶4的益害比释放黄瓜新小绥螨可有效控制二斑叶螨。同样密度比的情况下,5和10头黄瓜新小绥螨的释放量可显著控制西花蓟马的接入量。二斑叶螨密度的增加没有显著影响到黄瓜新小绥螨对西花蓟马的控制作用。西花蓟马可捕食黄瓜新小绥螨的卵,日捕食量达1.2粒。本文对利用黄瓜新小绥螨防治温室中西花蓟马进行了讨论。     

不同猎物饲喂对南方小花蝽捕食量和喜好性的影响

为探讨南方小花蝽对不同猎物的捕食喜好性,室内用西花蓟马、蚕豆蚜、二斑叶螨、混合饲料(同时饲喂3种猎物)分别饲喂南方小花蝽驯化两代,研究了4种饲喂处理的南方小花蝽初孵若虫、5龄若虫和雌成虫对西花蓟马、蚕豆蚜和二斑叶螨的捕食量和喜好性。结果显示不同猎物饲喂处理驯化的南方小花蝽1龄若虫对同一种猎物的捕食量和喜好性均不存在显著差异。南方小花蝽5龄若虫和雌成虫对某种猎物的捕食量因前期取食的猎物种类不同而有显著差异。南方小花蝽5龄若虫和雌成虫均表现出对西花蓟马2龄若虫的正喜好性。蚕豆蚜饲喂处理的5龄若虫和雌成虫对蚕豆蚜表现出正喜好性,除二斑叶螨饲喂处理外其余3种处理的南方小花蝽5龄若虫和雌成虫均表现出对二斑叶螨的负喜好性。以上结果表明4种饲喂驯化处理的南方小花蝽1龄若虫的喜好性不受前期取食猎物的影响,但5龄若虫和雌成虫对前期取食过的猎物的喜好性增强,存在一定的学习行为。     

芬兰真绥螨对苹果全爪螨的捕食作用研究

在实验条件下,系统研究了芬兰真绥螨Euseius finlandicus Oudemans对苹果全爪螨Panony-chus ulmi Koch的控制能力。研究结果表明:(1)在15～32℃的温度条件下,芬兰真绥螨雌成螨的捕食量随着温度的上升呈线型正相关。在15～25℃的温度内芬兰真绥螨的产卵量随温度升高而增加,在15℃下平均单雌产卵0.42粒,25℃时平均单雌产卵2.56粒;当温度升到32℃时单雌产卵下降为1.62粒,雌成螨的产卵量与温度的关系呈抛物线型。(2)在5～15头/叶的猎物密度下,雌成螨的捕食量随着猎物的密度增加呈线型正相关,而当猎物密度达到30头/叶时,芬兰真绥螨雌成螨的捕食量处于平稳状态。在5～15头/叶的猎物密度下,芬兰真绥螨的产卵量和产卵量均与猎物的密度呈线型正相关;当每头雌成螨捕食量为1.8～3.5头时,产卵量为1.0～1.5粒。(3)不同温度下,芬兰真绥螨对猎物的不同密度和虫态的功能反应可用圆盘方程II型进行拟合;在25℃条件下捕食效率最高且喜好捕食的虫态是卵和幼螨。     

巴氏新小绥螨对同一栖息地枸杞瘿螨的捕食功能反应

枸杞瘿螨Aceria pallida Keifer（Acari: Eriophyoidae）是枸杞上为害最严重的有害生物之一。近期在内蒙古地区发现植绥螨巴氏新小绥螨Neoseiulus barkeri Hughes（Acari: Phytoseiidae）与枸杞瘿螨可同时发生在野生枸杞上。为评价巴氏新小绥螨对枸杞瘿螨的捕食潜力,本研究在室内25±1℃、RH 65%±10%、16 L∶8 D的条件下,研究了巴氏新小绥螨对不同密度枸杞瘿螨成螨（30、50、70、90、110、130、150、170头）的捕食功能反应及搜寻效应。结果表明,巴氏新小绥螨的雌、雄成螨对枸杞瘿螨成螨的捕食功能反应均为Holling-II型,即巴氏新小绥螨雌、雄成螨的捕食量随着猎物密度的增加而增加,一直到猎物密度较高时趋于稳定;而巴氏新小绥螨雌、雄成螨的搜寻效应随着猎物密度的增加而降低。巴氏新小绥螨雌成螨对相同密度下的枸杞瘿螨成螨的捕食量均高于雄成螨,而且雌成螨的搜寻效应也强于雄成螨。巴氏新小绥螨雌成螨的攻击率（α=4.4121）高于雄成螨（α=2.4403）,而雌成螨的处理时间（Th =0.0094 d）短于雄成螨（Th=0.0196 d）;雌、雄成螨的理论最大日捕食量（T/Th）分别为106.61头和51.02头。研究结果显示巴氏新小绥螨对枸杞瘿螨有较好的捕食潜力,性别对巴氏新小绥螨捕食枸杞瘿螨的功能反应有显著影响。     

东亚小花蝽若虫对西花蓟马成虫的捕食作用

室内开展了东亚小花蝽二龄、四龄若虫对西花蓟马成虫的捕食功能反应与搜寻效应研究.结果表明,在26℃试验温度下其捕食功能反应均符合Holling Ⅱ型方程,东亚小花蝽若虫的捕食量随着猎物密度的增加而增加,搜寻效应随着猎物密度的增加而降低,捕食上限分别为9.2头和23.0头.     

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.