新疆塔里木盆地西北缘晚奥陶世疑源类

新疆塔里木盆地西北缘阿克苏和柯坪地区达瑞威尔期末期至凯迪期中期地层发育良好,大湾西沟剖面、四十场剖面和铁热克阿瓦提剖面地层保存良好的疑源类组合。该组合包括20属36种疑源类,以棘刺类、光球类和梭形类占优势。塔里木盆地西北缘疑源类组合与国内、外同期组合对比表明晚奥陶世疑源类古地理分区性减弱,部分疑源类分子分布仅限于晚奥陶世,且古地理分布广泛,具有生物地层学对比的潜力。新疆塔里木盆地西北缘数条剖面疑源类组成和多样性变化的不同可能与小环境的差异有关。本研究中疑源类属种组成及多样性变化趋势和柯坪地区海平面变化一致,反映了萨尔干组到其浪组下部有一次海侵过程。     

湖北宜昌奥陶系庙坡组疑源类

湖北宜昌地区庙坡组是达瑞威尔阶/桑比阶界线附近的地层,该段地层产出分异度较高,丰度适中的疑源类组合。该组合包括16属,28种,其中7个未定命名种,可与国内、外同期疑源类组合进行对比。庙坡组疑源类组合既产出晚奥陶世特征分子,也产出阿伦尼格期(弗洛阶上部—达瑞威尔阶底部)的特征分子,显示出一定的过渡特色。组合以Baltisphaeridium(17%—52%),Leiosphaeridia(6%—78%)占优势;反映了其沉积环境为离岸较远的外陆棚环境。     

微体古生物学报第24卷2007年总目次

第1期No.1新疆大湾沟晚奥陶世疑源类…………………………李军Reed WICANDER燕夔朱怀诚黄智斌唐鹏(1)Biostratigraphical and palaeogeographical significance of Late Ordovician Acritarchs from Dawangou,Xinjiang………………………LI Jun,Reed WICANDER,YAN Kui,ZHU Huai-cheng,HUANG Zhi-bin and TANG Peng(1)新疆准噶尔盆地芳3井晚白垩世孢粉组合的发现及其地质意义……………………………………………………………………………………………………………………………詹家祯师天明周春梅郑秀亮商华肖继南(15)Lat…     

新疆塔里木盆地北部晚奥陶世中期介形类

本文记述的介形类化石采自塔里木盆地北部柯坪地区大湾沟剖面坎岭组,共计8属14种。其中包括2新种和3未定种。Thrallella.Octonaria,Predarwinula三属为本介形类组合最为重要且最具特色的分子。据此推测,坎岭组时代为晚奥陶世中期(Caradocian)。     

浙江常山黄泥塘全球层型剖面的中奥陶世疑源类

浙江常山黄泥塘剖面在1996-1997年被国际奥陶系分会和国际地质科学联合会(IUGS)确立为全球中奥陶统达瑞威尔阶(Dariwillian)层型剖面,从该剖面宁国组Azygograptus suectcus-Exigraptus clavus笔石带至Undulograptus sinicus笔石亚带下部的页岩及灰岩中获得丰富的,保存不很好的疑源类化石,它们包含26个形态属,41个已知种和12个未定名种.该宁国组疑源类组合极少有环冈瓦纳古陆的“冷水“类型,根据疑源类类型在地层柱的首次出现,可划分两个与Azygograptus suecicus和Undulograptus austrodentatus笔石带相吻合的疑源类生物地层单元,结合中国南方在奥陶纪的古地理位置加以讨论,当前疑源类组合表明,中奥陶世环冈瓦纳古陆的“冷水“洋流至下扬子区已很微弱.     

湖北宜昌黄花场大湾组一些疑源类

湖北宜昌黄花场大湾组底部的疑源类有14属34种,其中9新种和8未定种,主要由下列4属Baltisphaeridium,Gorgonisphaeridium,Peteinosphaeridium及Veryhachium的分子组成,约占总类型的53.0％,其次为Leiosphaeria及Tectiheca两属的分子,约占14.7％。其组合指示的地质时代属早奥陶世Arenigian期。     

新疆哈密地区晚泥盆世疑源类化石的发现及地质意义

从新疆哈密地区石城子北剖面7件样品获得分异度较高、有机质壁显著炭化保存的疑源类化石,根据其形态特征,共鉴定出14个形态属和15个形态种(其中8个未定种,3个比较种)。结合国内外古生代晚泥盆世已知疑源类组合进行比较,清楚表明当前获得的疑源类组合代表了晚泥盆世海洋微体浮游植物群面貌。我国涉及晚古生代疑源类生物地层的调查研究相对薄弱,而有关晚泥盆世疑源类化石的发现和报道更为匮乏,当前疑源类化石的发现,填补和丰富了新疆乃至国内晚泥盆世疑源类化石研究资料。该发现佐证了关于卡拉麦里洋在早石炭世闭合的认识;作为基础食物链的海洋微体浮游植物是重要成烃生物,晚泥盆世疑源类的保存预示研究区域具有石油、天然气勘察的前景。     

西藏聂拉木晚奥陶世的介形类

文中首次报道西藏聂拉木地区亚来水厂剖面上奥陶统甲曲组介形类16属30种,介形类以古足介目类和圆足介目类为主,少量速足介目类。根据该剖面介形类时代特征,可以推断甲曲组应属于晚奥陶世早期,大致为Sandbian期—Katian期。该介形类生态组合为艾菲尔生态型,指示甲曲组在沉积时为近岸浅水环境。晚奥陶世喜马拉雅地层区与华南扬子区及塔里木介形类面貌相似,应属于相同的生物地理分区。     

青海省北祁连中三叠统孢粉组合及其沉积相意义

青海省祁连县俄博乡大擦汗沟、土圈沟、柯柯里等三叠系剖面的粉砂岩、砂质页岩、泥质页岩中首次发现较丰富的孢粉和疑源类化石,计57属98种。孢粉中的蕨类植物孢子占总组合的44.6%,裸子植物花粉占33.9%;疑源类有8属13种,占21.5%,称Verrucosisporites-Triadispora-Trematosp haeridium孢粉组合。该组合面貌与国内外中三叠世不同相区的孢粉组合特征基本相似并可对比。北祁连山南坡本组合及上下其它组合中海相疑源类的存在,表明该区在三叠纪受到海水影响,海水完全退出是在三叠纪之后。文章还初步探讨其沉积相意义。     

湖北宜昌黄花场早奥陶世疑源类的新类型

该文报道了湖北宜昌黄花场下奥陶统大湾组下段的疑源类（海洋微体浮游植物化石）新类型,描述和建立３新属：Ｐａｐｉｌｌｉｆｅｒｕｍｇｅｎ．ｎｏｖ．,１ｇｅｎ．ｎｏｖ．和Ｙｉｃｈａｎｇｉａｇｅｎ．ｎｏｖ．;２新种：Ｐａｐｉｌｌｉｆｅｒｕｍｉｒｒｅｇｕｌａｒｅｇｅｎ。ｅｔｓｐ．ｎｏｖ．,Ｙｉｃｈａｎｇｉａｂｉｐｏｒｏｓａｇｅｎ;ｅｔｓｐ。ｎｏｖ。及重新修改和组合的３属、种：Ｐａｐｉｌｌｉｆｅｒｕｍｒｈａｂｄｏｃｌａｄｉｕｍ（Ｌｕ）ｃｏｍｂ．ｅｔｅｍｅｎｄ．ｎｏｖ．,Ｐ。ｓｔｒｉａｔｕｍ（Ｌｕ）ｃｏｍｂ．ｅｔｅｍｅｎｄ。ｎｏｖ。和Ｓｔｅｌｏｍｏｒｐｈａｅｒｃｈｕｎｅｎｓｉｓ（Ｆａｎｇ）ｃｏｍｂ;ｅｔｅｍｅｎｄ．ｎｏｖ．这些疑源类新类型目前仅见于我国西南的部分地区的早奥陶世地层。它们为探讨早奥陶世海洋微体浮游植物的区域分布及扬子地台的古地理位置,提供了重要的证据．     

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.