血吸虫生殖生理的研究进展

血吸虫体外培养研究工作经过了半个世纪的努力,取得了很大的进展,其中较突出的有 Clegg[1]从童虫培养至成虫; Basch[2]使尾蚴人工转变童虫后继续体外培养达到童虫发育,雌雄合抱,雌虫产卵,但卵为异常卵.目前为止,无论在曼氏或日本血吸虫均在体外培养成功,但两种血吸虫所产的卵均为异常卵,而血吸虫的生殖生理研究是寻找血吸虫体外培养不育的关键.     

日本血吸虫尾蚴经人工方法转变的童虫体外培养的研究

本文介绍了日本血吸虫体外培养系统。建立了较适于童虫生长发育的B41培养基。尾蚴经人工方法转变的童虫在体外可发育至雌雄合抱,雌雄生殖器官形成。雌虫可达产卵阶段,但未具备正常的产卵机能。培养的血吸虫在体外至少可存活110天。     

星豹蛛生活史的初步观察

据室内观察,星豹蛛在安徽省芜湖市(12.7—29.8℃)一年发生不完全的二代,以若蛛和成蛛越冬。雌蛛一生只交配一次,多次产卵。越冬代雌蛛平均产卵囊2.4个,每个卵囊平均具卵52粒;第一代雌蛛平均产卵囊2.2个,每个卵囊平均具卵39粒。卵粒孵化率最低为65％,最高达100％。从若蛛发育至成蛛,一般蜕皮5—6次,少为7次,雌雄性比为1.5:1,成蛛平均寿命为133.2天。     

台湾铗蠓的生活史研究(双翅目:蠓科)

在重庆地区结合室内、外的情况观察了台湾铗蠓的生活史。台湾铗蠓吸大、小白鼠仔鼠,仔兔和人的血液,碳水化合物在卵巢发育过程中并不需要。雌虫吸取一份充足的血液后,胃血消化和卵巢发育之间是完全一致的。半饱时,卵巢可正常发育产卵。除高级生殖营养外,尚存在着低级生殖营养。 试管饲养下,20-34℃时,多数在吸血后2-4日产卵。产卵率85-98.12%。每雌产卵24-147个,平均79.04个。 受精卵均能孵化,在水内也能正常孵化,卵对干燥具有一定的耐受性。饲育期间,土壤必须保持湿润,多水对蛹期极为不利。幼虫以血粉、肝粉、蛋黄粉、酵母粉和海绵藻为食物。 幼期发育的时间:蛋黄粉培养,在7-20℃,RH66-84.5%时,自卵至成虫为136-164天,血粉、肝粉培养,在15.5-25.4℃,RH74一83%时,自卵至成虫分别为33-63和38-59天。蛋黄粉和酵母粉培养,在18-24.6℃,RH72-88%时,自卵至成虫分别为29-35和31-44天。海绵藻培养,在20-25.2℃,RH76-85%时,自卵至成虫为14-39天。     

短时高温对加州新小绥螨发育的影响

为了探究高温逆境条件下加州新小绥螨的生存特性对其种群发育的影响,利用短时高温刺激试验,研究加州新小绥螨卵、幼螨、雌成螨在35、38、42、45 ℃等4个温度下、处理1～8 h后的孵化率、存活率、后期发育历期及繁殖的影响.结果表明: 处理温度越高,时间越长,卵和幼螨的存活率越低,其后续发育历期随处理温度升高和时间增加先缩短后延长.当温度为38 ℃,处理8 h后,卵的后续发育历期最短,为4.1 d.卵在45 ℃下处理2 h以上将不能正常孵化,而幼螨在45 ℃下处理8 h后不能存活;雌成螨产卵期和产卵量基本随温度升高先增加后降低,35 ℃处理8 h后,单雌产卵量最高,为38.9粒;38 ℃处理8 h后,单雌产卵量为36.7粒;45 ℃处理8 h后,单雌产卵量仅为14.5粒.短时高温主要影响加州新小绥螨的孵化率、存活率和后续发育历期,对雌成螨的产卵前期和存活率影响较小.     

短时高温对加州新小绥螨发育的影响

为了探究高温逆境条件下加州新小绥螨的生存特性对其种群发育的影响,利用短时高温刺激试验,研究加州新小绥螨卵、幼螨、雌成螨在35、38、42、45 ℃等4个温度下、处理1～8 h后的孵化率、存活率、后期发育历期及繁殖的影响.结果表明: 处理温度越高,时间越长,卵和幼螨的存活率越低,其后续发育历期随处理温度升高和时间增加先缩短后延长.当温度为38 ℃,处理8 h后,卵的后续发育历期最短,为4.1 d.卵在45 ℃下处理2 h以上将不能正常孵化,而幼螨在45 ℃下处理8 h后不能存活;雌成螨产卵期和产卵量基本随温度升高先增加后降低,35 ℃处理8 h后,单雌产卵量最高,为38.9粒;38 ℃处理8 h后,单雌产卵量为36.7粒;45 ℃处理8 h后,单雌产卵量仅为14.5粒.短时高温主要影响加州新小绥螨的孵化率、存活率和后续发育历期,对雌成螨的产卵前期和存活率影响较小.     

台湾铗蠓吸血和生殖的观察

实验室条件下,台湾铗蠓[Forcipomyia (Lasiohelea)taiwana]吸食小鸡、小白鼠乳鼠的血液,吸血率为7.07%±1.64和65.70%±5.41.亦能通过人胎盘膜进行离体喂血,吸血率为35.44%±6.91.80对成蠓用人工交配的方法其交配率达到19%,但未授精.雌蠓未交配能吸血、产卵但不孵化.雌蠓饱血一次,发育成熟的卵平均为49.23±21.33个,实际产出的卵平均为35.35±22.38个.关于交配和产卵习性也做了观察.     

室温下保存的小鼠屠体卵巢GV卵的发育能力

将ICR系雌性小鼠处死并在10℃、15℃、20℃和25℃下依次保存8、14、24和48 h后,采集其体内的卵巢GV期卵,采用常规方法进行体外成熟和体外受精,获得的2细胞期胚经体外培养或胚胎移植观察其发育能力.其结果,在10℃下保存24 h、15℃下保存14 h、20℃下保存8h和25℃下保存4 h后,其体内附有卵丘细胞的GV卵的体外成熟-体外受精后的2细胞率分别为14%、9%、10%和10%,随着保存温度的提高和保存时间的延长,带有颗粒细胞GV期卵的比率明显降低,同时其GV期卵经体外成熟及体外受精后的2细胞率明显降低.在20℃下保存24 h和25℃下保存14 h时,难以获得形态正常的GV期卵;体外受精获得的2细胞期胚经体外培养,总体上有64%的胚胎发育至扩张囊胚,未见有保存温度和保存时间的显著影响,且利用在15℃保存8 h后的GV卵获得2细胞期胚的移植获得正常新生小鼠.上述结果表明,雌性动物室温条件下死亡后,若能短时间及时采集其体内GV期卵并体外成熟、体外受精,体外培养及胚胎移植技术,就有可能获得新生后代.     

人工养殖条件下东方蝾螈的繁殖生物学

通过室内饲养观察,重点研究了东方蝾螈的产卵行为、受精卵孵化、仔螈的变态发育等繁殖生物学.东方蝾螈雌螈产卵前有明显的筑巢行为,分批产卵,产卵时间不集中,产卵期持续46～98 d,平均产卵期为78 d±14 d,产卵高峰期在5月上中旬,平均产卵量为101±56枚;温度对受精卵孵化影响十分显著,3月份产的卵平均54.1 d孵出仔螈,6月份产的卵平均11 d孵出仔螈,在15～26℃的自然水温条件下,受精卵一般需要11～30 d孵出仔螈;仔螈的变态发育与温度、饲料等因素密切相关,在24～25℃的控温养殖条件下,仔螈40 d后外鳃开始萎缩,68～79 d完成变态发育,但在自然水温下,只有78%的仔螈当年能完成变态发育.     

几种微蛛生育力和繁殖力的比较研究

区别生育力和繁殖力,具有很重要的生态学意义。蜘蛛的生育力是其产卵量多少的量度。从卵囊出来的存活幼蛛数既不表示生育力,也不表示繁殖力。笔者认为此处的繁殖力系指出卵囊的存活幼蛛数和没出卵囊的处于各发育阶段的个体,而不包括那些没有任何发育迹象的卵。微蛛种群数量大、历期短,繁殖快、能捕食多种农业害虫,因而许多学者对繁殖习性和产卵量等进行了较详细的研究。但是,他们并没有把生育力和繁殖力区别开来加以研究,也没有给获得的数据赋予生态学意义。我们于1987年对四种微蛛的生育力和繁殖力作了比较研究。材料和方法供试蜘蛛:草间小…     

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.