粤北韶关早石炭世大塘期牙形刺

作者发现了广东韶关早石炭世大塘期一些牙形刺,其中石磴子组11属20种(包括1新种和1新亚种),梓门桥组8属9种,并与国内外一些地区相当的牙形刺带进行了比较和讨论。对重要的台型牙形刺和新种作了简要描述。根据牙形刺的面貌,梓门桥组中下部可能属早石炭世。     

安徽石台奥陶纪弗洛期-大坪期牙形刺多样性的演变

基于安徽石台栗阳柳树亭下、中奥陶统紫台组牙形刺的系统研究,对该地区早奥陶世弗洛期一中奥陶世大坪期牙形刺多样性演变作了初步分析,发现牙形刺的简单分异度在弗洛晚期Oepikodusevae带达到峰值,有17属20种。之后,牙形刺分异度呈下降趋势。演变的总体趋势与湖北宜昌地区同期牙形刺的研究结果一致,其峰值出现的时间（Oepikodusevae带,相当于笔石Didymograptellus eobifidus带上部,Corymbograptusdeflexus带,及Azygograptussuecicus带下部）与华南上扬子区腕足动物宏演化趋势（首次峰值出现在Didymograptelluseob—ifidus带）大体相似,但比三叶虫多样性演变在奥陶纪的首次峰值（出现在Exigraptus clavus带）早,比扬子台地笔石多样性演变的首次峰值（在Acrograptusfiliformis带和Didymograptelluseobifidus带下部）晚。分析显示,该地区早、中奥陶世牙形刺多样性演变与海平面变化存在密切关联。     

西藏申扎地区晚奥陶世-志留纪牙形刺

本文描述的牙形刺采自西藏申扎地区晚奥陶世-志留纪刚木桑组、德悟卡下组和扎弄俄玛组。根据牙形刺首次提出该区志留系四分方案和确定了奥陶系与志留系的界线位置,为西藏自治区的志留系的研究与划分,提供了重要的依据。     

江西武宁宁国组上部牙形刺兼论黑色页岩的形成环境和牙形刺的生态

本文研究了江西武宁奥陶系宁国组上部黑色页岩中的牙形刺。共发现牙形刺11属15种,其中Eoplacognathus suecicus Bergstrom,Eoplacognathus foliaceus(Fahraeus)为世界性分布的牙形刺带化石,为宁国组上部黑色页岩的划分与对比提供了可靠的依据。根据牙形刺的保存状态,笔者推论当时本区水底层为偏酸性还原环境,并认为牙形刺动物是浮游生活在不同深度的水层中。     

广西象州四排组的几种牙形刺

本文根据牙形刺确定四排组的石朋段和(口六)回段为早泥盆世埃姆斯阶晚期的沉积,文中描述了牙形刺8属13种,其中有1新种和4个未定种。     

塔里木中央隆起区上奥陶统的牙形刺

塔里木板块中央隆起区的上奥陶统,即巴楚露头剖面吐木休克组和良里塔格组以及塔克拉玛干沙漠腹地塔中油田井下良里塔格组皆为灰岩相.作者对前人报道的牙形刺带作了修改,首次系统描述牙形刺动物群全貌,共计14属21种.在曾归入Pygodus serra带和P.anserinus带的吐木休克组底部和下部发现Yangtzeplacognathus jianyeensis,故应改为Yangtzeplacognathus jianyeensis带;吐木休克组中部因发现Baltoniodus alobatus和B.variabilis共生,应属B.alobatus带.在Yangtzeplacognathus jianyeensis带和Baltoniodus alobatus带之间尚未发现可靠的B.variabilis,因此是否存在B.variabilis带尚存疑问.巴楚露头区上奥陶统的牙形刺序列由下而上应为Yangtzeplacognathus jianyeensis带,Baltoniodus variabilis带?,B.alobatus带和Belodina confluens带.塔中的良里塔格组则可识别出B.confluens带和Yaoxianognathus yaoxianensis带.将中央隆起区牙形刺动物群组合与其相邻的柯坪地块进行对比,说明晚奥陶世因两个地理区水深的差异导致牙形刺带完整性的差异.     

山西太原组牙形刺的发现

1980年4月,山西省煤田地质勘探公司煤田勘探队,在太原西山七里沟、柳测沟,太原东山麻地沟,霍县寺庄,阳泉和顺南峪、水泉沟和朔县担水沟等地,测制了上石炭统太原组的7个剖面,并系统地采集了牙形刺样品。除朔县担水沟剖面未发现牙形刺外,在其它各剖面的样品中,都含有较丰富的牙形刺,共计3属、8种。根据牙形刺分析,山西太原组的层位,应属     

中国奥陶纪牙形刺分区和生物地层

根据牙形刺动物群的性质和分布，中国奥陶纪牙形刺在Ｔｒｅｍａｄｏｃ以后可以明显区分为两大地理区，即华南区和华北区。华南区的牙形刺动物群几乎与北大酉洋型的牙形刺动物群完全一致，属冷水型动物群。华北区的牙形刺动物群与北美中大陆区的牙形刺动物群较为接近，但有自己的地方型特征，属暖水动物群。总结了两个不同地理区的牙形刺生物地层，并较详细地进行了不同区的国内外对比。     

浙江桐庐早二叠世船山组介形类化石

研究报道的介形类化石系采自浙江省桐庐县瑶林镇沈村剖面早二叠世船山组,计14 属4 亚属22 种,包括4新种和4未定种。其中12属4亚属和19种产自船山组第三段,并被归为Hollinella(Praehollinella) ema ciata Basslerella ola 组合,代表早二叠世船山世隆林期。牙形刺化石主要产自船山组第一段,带化石Streptogna thodus elegantulus 及其共生的其它牙形刺化石,指明船山组第一段的时代为中、晚卡西莫夫期到早格泽里期。根据介形类动物群生态组合和岩石特征,推测船山组第三段是在温暖的近岸浅水且为低能的开阔海环境下沉积的。     

豫淮盆地太原组顶部斯威特刺(Sweetognathus)种的分类修正及其地层意义

作者通过对豫淮盆地太原组顶部灰岩中牙形刺的研究,发现Sweetognathus动物群较为丰富,计4属10种,含一个新种:Sweetognathuspraeiranicussp.nov.。其中以Sweetognathus最为繁盛,并对其种的分类进行了修正,将原定的Sweetognathusinornatus的大部分标本归入Sweetognathusmerrilli。根据新的分类,建立了两个组合带,即Sweetognathusmerrilli带和Sweetognathuswhitei-Xuzhougnathusmonoridgosus带。通过与国内外相当牙形刺组合带(带)的对比,初步认为该动物群属中、晚萨克马尔到早亚丁斯克期。     

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.