发头裸腹Sou生长,生殖的研究

发头裸腹ＳｏｕＭｏｉｎａｉｒｒａｓａＢｒｅｈｍ（Ｃｌａｄｏｃｅｒａ）在２５±１℃下有３个幼龄,６个成龄,平均寿命为１６７．７ｈ,平均最大体长为１．７５ｍｍ平均产仔量为１１７个。ｒｍ为１．３５８／ｄ;在３０±１℃下有３个幼龄,７个成龄,平均寿命为１２１．０ｈ平均最大体长为１．７１ｍｍ,平均产仔量为１０６．６个,ｒｍ为１．６５０／ｄ。在生命初期３０±１℃下体重增长率（ｄＷ／ｄｔ）,相对体长增长率（ｄＬ     

生活周期毒性试验动物─—方形网纹溞的生物学

在实验室条件下研究方形网纹的生物学.试验时水温25±1℃,饲以斜生栅藻.初生幼体平均体长0.40mm,第1成龄0.96mm,最大体长可达1.45mm,体长增长(1_t,单位mm)与年龄(t,d)的关系可以表达为1t=1.43-e-0.268t,平均寿命22.73(17.10-25.00)d,其中包括3个幼龄和13个成龄.在3.91d达到性成熟.7d内生殖3胎,产仔40(19-47)个.一生生殖222.0个幼体,平均每胎18.5(4.8-23.6)个.生殖量最大出现在第6成龄.这时的年龄11.05d,体长1375mm.从初始10个个体的种群计算,种群生长曲线呈Logistic型,可以如下表达 y=2220/1+e6.239-0.572t 式中y表示总个体数,t表示时间(d).内禀增长能力(rm)为0.540/个/d,净增殖率(Ro)147.360/世代,世代平均周期(T)9.246d,周限速率(λ)1.716/个/d.       

温度对喜马拉雅低额溞生长与生殖的影响

对采自中国云南省高海拔地区-稀有低额溞-喜马拉雅低额溞(Simocephalus himalayensis)在低海拔地区实验室内不同温度梯度下的生长及生殖能力进行了研究.结果表明:高海拔地区生活的低额溞在低海拔地区的相应环境中同样生长繁殖良好,其繁殖率、最大生殖量及种群的增长能力不受海拔高度及不同环境条件的影响.在一定温度条件下(15-31℃,误差为±1℃),喜马拉雅低额溞的发育速率随温度的升高而加快,但在32℃时减慢.在通常培养条件下,喜马拉雅低额溞一般有4个幼龄期(15℃时部分溞体有5个幼龄),16-19个成龄,平均寿命通常为74d(15℃)、54d(20℃)、39d(25℃)和24d(30℃).平均总产仔量在15-25℃最高,分别为449个(15℃)、482个(20℃)和447个(25℃).各温度梯度下的体长增长模型都表明,其体长与龄期之间存在显著的对数关系.每溞平均生殖量以20℃时最高,种群的内禀增长率(rm)和一生的生殖次数都以25℃时最高,净增殖率(R0)以20℃最高.喜马拉雅低额溞最适合的繁殖温度范围在15-25℃.研究还对该种与相应种类在不同温度条件下的生殖量和生物学特性进行了比较.     

温度和食物浓度对老年低额溞生长与生殖的影响

在20℃和25℃培养温度下研究了3种食物浓度对老年低额(Simocephalus vetulusOF Müller)生长与生殖的影响。结果表明:老年低额有4个幼龄(在20℃、低食物浓度下有5个)和10-13个成龄。成龄的龄期明显高于幼龄,第一成龄的发育时间一般最长。在相同温度下,老年低额的首次怀卵所需时间及各龄期一般随食物浓度的增加而缩短,而各龄的平均体长及其生殖量则呈相反的趋势。在相同的食物条件下,25℃老年低额在生长后期的平均体长明显高于20℃,而各龄期却小于20℃。最大体长是2.82mm,出现在25℃、高食物浓度下的第16龄。老年低额的平均最大生殖量和最大内禀增长率分别为144个和0.41/d,均出现在25℃和高食物浓度下。统计分析显示老年低额的生殖量与体长之间存在显著的相关性。老年低额的食物浓度域值小于1×104cells/mL(Scenedesmus obliquus)。作者探讨了老年低额在渔业生产中作为活体饵料养殖对象的可能性。       

柏小爪螨实验种群生命表的组建与分析

组建并分析了柏小爪螨实验种群生命表。在25℃恒温条件下,种群的内禀增长力rm为0．1274,周限增长率λ为1．1358／d,净增殖率Ro为12．8746代,平均世代周期T为20．0586d,种群增长一倍需要的时间t为5．4407d。     

温度及pH对隆线溞生长和生殖的影响

研究了隆线溞(Daphnia carinata)在不同温度(15、20、25、30℃)和pH(6、7、8、9、10)影响下的内禀增长率(rm)、周限增长率(λ)、平均世代周期(T)、净生殖率(R0)、平均寿命、第一怀卵日、平均生殖间隔期和总生殖量.结果表明,温度对隆线溞的生命参数有显著影响,30℃组的内禀增长率(rm)...     

微齿喜马拉雅低额溞的生殖与发育

对微齿喜马拉雅低额溞（Ｓｉｍｏｃｅｐｈａｌｕｓ ｈｉｍａｌａｙｅｎｓｉｓ　ｍｉｏｒｏｄｕｓ）的生殖和发育进行研究的结果表明：在２０±１℃换水条件下，喂以斜生栅藻（４０万个／ｍｌ），此　有４个幼龄、１６个成龄，平均寿命４８．７±８．９２天。平均总产仔量３６１．ｌ±２１．５个，最大生殖量在第１０龄（第６成龄）。已经证明从冬卵（受精卵）来的孤雌生殖溞在体长和产仔量上都高于其来自孤雌卵的下代孤雌　。两性生殖与降低温度有关，发生在秋季生殖高峰期水温已下降时，与食物的多少无直接关系。本种在自然界属于单周期型，它的交配行为特殊与其仰游习性相适应。文章对冬孵和孤雌卵的发育做了描述。     

斯氏新小绥螨以神泽氏叶螨为猎物的发育与实验种群生命表研究

本研究进行了斯氏新小绥螨Neoseiulus swirskii （Athias-Henriot）以神泽氏叶螨Tetranychus kanzawai（Kishida）为猎物时,在15℃、18℃、20℃、25℃、30℃和35℃下的发育历期和实验种群生命表的研究,结果表明15℃时斯氏新小绥螨不能完成发育,18℃时仅少量个体能完成发育.在18～35℃之间,雌螨的发育历期为7.15～18.70 d,雄螨的发育历期为4.00～16.20 d.在20℃～35℃之间,斯氏新小绥螨的雌雄性比（♀∶♂）随着温度的升高而变小,20℃时性比最大（1.77）,25℃时净增殖率（R0）最大（36.497）,35℃时世代生长周期最短（15.433）,30℃时内禀增长率（rm）和周限增长率（λ）均最大,分别为0.197和1.218,种群倍增时间（t）最短（3.513）;随着温度的增加,斯氏新小绥螨的平均寿命逐渐变短,20℃时最长（73.40±1.26 d）,35℃时最短（25.10±1.20d）;25℃时每雌平均产卵量最高（60.44±1.51粒/雌）,35℃时日平均产卵量最高（2.06±0.09粒/雌/d）.     

不同温度下稻螟赤眼蜂在黏虫卵上的种群生命表

稻螟赤眼蜂Trichogramma japonicum Ashmead是水稻二化螟Chilo suppressalis(Walker)的优势卵寄生蜂。本文构建了以黏虫卵为中间寄主,稻螟赤眼蜂在20℃、25℃、30℃、33℃四个温度条件下的生命表。研究结果表明利用黏虫卵繁育稻螟赤眼蜂时,不同温度下其生长发育和繁殖均存在显著差异,雌蜂平均寿命随温度的升高呈下降趋势,在20℃条件下,雌蜂平均寿命为1.44 d,显著长于其它温度,当温度为30~33℃时,雌蜂寿命最短,平均为0.59 d。在温度为20℃和25℃时,稻螟赤眼蜂的羽化率显著高于温度较高的30℃和33℃,平均为94.73%。在25℃条件下,黏虫卵繁育的稻螟赤眼蜂的净生殖力(R 0)最大,达到31.9176,单雌寄生卵数最多,为32.88个,表现出最强的繁殖能力,而在30℃条件下,瞬时增长率r m和周限增长率λ达到最大值。综合生命表参数、单雌寄生黏虫卵数、寿命、羽化率等指标,利用黏虫卵工厂化繁殖稻螟赤眼蜂的最佳温度为25℃。本研究为利用黏虫卵大量繁殖稻螟赤眼蜂提供了有价值的参考。     

胡瓜钝绥螨捕食茶橙瘿螨的实验种群生命表及捕食作用初探

本在25℃条件下初步研究了胡瓜钝绥螨捕食茶橙瘿螨的实验种群生命表、各螨态取食量及猎物－－卵转化率。25℃时胡瓜钝绥螨的净增殖率R0＝21．7862,世代平均周期T＝16．1822,内禀增长率rm＝0．1904,周限增长率λ＝1．2097,种群倍增所需时间t＝3．6405。日平均产卵量2．19粒／天,总产卵量36－48粒／雌,平均38．97粒／雌。胡瓜钝绥螨雌螨－生取食量1978．49头。雄螨取食量879．56头。猎物：卵转化率为79．78头茶橙瘿螨：2．19粒胡瓜钝绥螨卵。     

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.