中国大鲵核型特征研究

采用外周血培养和制备染色体标本的方法,分析雌雄中国大鲵的核型特征.结果 表明:(1)中国大鲵染色体数目为2n=60;(2)染色体由大染色体和微小染色体组成,属于两型性染色体;(3)大染色体中有8对中部着丝粒染色体和2对亚中部着丝粒染色体;(4)微小染色体有20对,大多是端部着丝粒染色体,在雌性中发现了4对双臂染色体,第11、25号是亚中部着丝粒染色体,第23、24号是中部着丝粒染色体.表明中国大鲵是两栖动物中的原始类群.     

蝙蝠科七种蝙蝠的核型

报道了贵州7 种蝙蝠科蝙蝠的核型。伏翼和印度伏翼的染色体数为2n = 26 , 常染色体都由10 对双臂染色体和2 对微小点状染色体组成, N.F = 44 , 性染色体是大小悬殊的端着丝粒染色体; 两者核型的主要区别在于前者的No.3 是中着丝粒染色体, 后者为亚中着丝粒染色体; 大鼠耳辐(四川亚种) 、水鼠耳蝠和西南鼠耳蝠的染色体数都是2n = 44 , 常染色体都由4 对中着丝粒染色体和17 对端着丝粒染色体组成, N.F = 50 , 其中大鼠耳蝠(四川亚种) 和水鼠耳蝠核型非常相似, 西南鼠耳蝠与前二者有一定区别; 山蝠(福建亚种) 是2n = 36 , 常染色体包括7 对中着丝粒染色体、1 对亚中着丝粒染色体和9 对端着丝粒染色体, N.F = 50 ; 南蝠2n = 50 , 常染色体由24 对端着丝粒染色体组成, N.F = 48 , X染色体是最大的中着丝粒染色体。     

天台蛙和合征姬蛙的核型及其银染色研究

本文报道了天台蛙和合征姬蛙的核型和Ag-NORs。用骨髓细胞为实验材料,采用离心法或蒸气固定法制作染色体标本。结果：天台蛙2n=26,由5对大型染色体和8对小型染色体组成,其中有2对st染色体,6对sm染色体和5对m染色体。No.11染色体上有一恒定的次组痕;合征姬蛙2n＝24,包括6对大型染色体和6对小型染色体,除NO-3为st染色体外,其余的均为m染色体。一对次绕痕位于No.9染色体长臂上。天台蛙和合征姬蛙的Ag-NoRs分别位于No.11和No.9染色体的次槛痕区,未见有扩增现象。     

应用荧光原位杂交(FISH)技术研究黑叶猴染色体易位

本文应用染色体荧光原位杂交(FISH)技术,利用人9号和14号染色体特异探针,对深低温冻存和长期传代的黑叶猴细胞株染色体畸变进行了分析.确定在长期冻存和传代过程中,一些黑叶猴细胞在No.12和No.17染色体之间发生了易位,一条 No.17染色体发生断裂,断裂点在17q13,断裂片段17q13-17qter易位到一条 No.12染色体长臂末端,形成一条小的中着丝粒的和一条具较长长臂的衍生染色体即 der(17) 和 der(12).结果表明,荧光原位杂交技术用人染色体特异探针不仅能检测出人类染色体畸变,也能有效地检测灵长类动物染色体畸变.     

北五味子染色体核型分析

本文研究了北五味子的染色体核型.其体细胞染色体数目2n=28,具13对中部着丝点染色体,1对近中部着丝点染色体.在整个染色体中并未发现随.按Levan的染色体分类标准,其染色体核型组成是:K(2n)=2x=28=26m+2Sm.     

广西杉木两类型染色体核型初步究研

本文对广西杉木(Cunninghamia lanceolata)两个类型(油杉C.lanceolata cv.‘lanceolata’和糠杉C.lancolata cv.‘glauca’)的核型进行了初步研究。二者的染色体数目为2n=22,均由具有9对中央着丝点染色体,1对近中着丝点染色体(No.6),1对带随体染色体(No.1)组成。在部分油杉细胞里发现有B染色体,而在糠杉细胞里未发现B染色体,油杉染色体长度4.29—15.10微米,糠杉染色体长度4.74—14.54微米。     

人类X染色体与Y染色体是否为同源染色体

对同源染色体的概念及人类X染色体与Y染色体的来源、形态结构、功能以及减数分裂中的行为等进行了讨论.X染色体与Y染色体虽然在形态、大小以及所含的基因等方面有差别,但从综合分析看,二者属于同源染色体,或者属于特殊的同源染色体.     

染色体数目减少及B染色体产生的进化基因组学模型

在长期进化过程中,染色体数目展示出动态性变化.关于真核生物染色体进化仍有许多谜团,一个是如何维持染色体数目,另外一个是B染色体是如何产生的.全基因组测序工作的开展为认识染色体数目变化提供了新的机会,特别是反复的多倍化事件后染色体的改变有助于人们理解相关生物学规律和机制.通过比较基因组学分析,本文提出了染色体数目变化与B染色体产生的模型,认为染色体数目的减少主要是由于染色体融合,并且端粒的丢失及B染色体的产生在基因组重新整合和染色体数目减少中起着重要作用.     

雅小叶蝉属六种昆虫的染色体研究(半翅目:叶蝉科:小叶蝉亚科:小叶蝉族)

研究了雅小叶蝉属Eurhadina 6种昆虫的染色体数目、性别决定和染色体行为.结果表明:该属6种昆虫染色体的数目变化范围为n=7-9,E.rubra、E.flavicorona和E.tripunctata具有相同的染色体数目,均为n=9,E.exclamationis的染色体数目为n＝8,E.fusca和E.rubr...     

丽纹攀蜥粗线期染色体核型及微小染色体的分析

本文以精巢、四肢骨和脊椎骨为材料,利用直接制片法制备了丽纹攀蜥（Japalura splendida）染色体标本,首次对其精巢减数分裂粗线期染色体,特别是微小染色体的长度进行了测量,描述了染色体特征,并进行了核型分析.同时与二倍体细胞染色体的核型进行了比较,发现11对微小染色体类型中包括8对中着丝粒染色体、2对端着丝粒染色体和1对点状染色体.     

Systematic studies on the Pompilidae occurring in Japan: Genus Agenioideus Ashmead (Hymenoptera), supplement

Two species of the pompilid genus Agenioideus occurring in Japan are described: A . ( Agenioideus ) kokyo and A . ( A .) cinctellus . The former is new to science and the latter is recorded from Japan and Taiwan for the first time. A brief summary of the biology of A. cinctellus , distinguishing characters between A. ( A. ) ishikawai Shimizu, 1989 and its relatives, and a key to all Japanese species of this genus are presented. Psammochares cinctellus f. rufa Haupt, 1938 and A . ( A. ) pacificus Lelej, 1994 are newly synonymized with A. cinctellus . A new combination is proposed: A . ( A .) maculipes (Smith, 1870) (= Pompilus maculipes Smith), which is found in Southeast Asia to South Asia. Agenioideus ishikawai is newly recorded from Korea and China.     

A revision of the genus Annesorhiza (Apiaceae)

The genus Annesorhiza is revised and twelve species are recognized, of which two are newly described: A. altiscapa, A. burttii, A. flbrosa, A. flagellifolia, A. grandiflora, A. lateriflora, A. latifolia, A. macrocarpa, A. nuda, A. schlechteri, A. thunbergii and A. wilmsii. A. marlothii is reduced to synonymy under A. lateriflora , a species hitherto poorly known as Peucedanum lateriflorum. A. thunbergii is only known from the type specimen. A. elata, A. hirsuta and A. villosa are sunk under A. grandiflora. A. fúicaulis has recently been excluded from Annesorhiza on the basis of fruit structure. A key to the species is provided, an update on the nomenclature, typification of names and distribution maps are provided for all the species.     

Three new species of Aiphanes (Palmae) with notes on the genus in Ecuador

Twelve species of the palm genus Aiphanes occur in Ecuador. The morphological variation in the genus is surveyed, and the distribution of the Ecuadorean species is discussed. A key to the species of Aiphanes in Ecuador is provided. Aiphanes chiribogensis, A. grandis , and A. verrucosa are described as new species, and illustrated. Aiphanes caryotifolia, A. eggersii, A. erinacea, A. fosteriorum, A. gela-tinosa, A. macroloba, A. schultzeana , and A. tricuspidata are characterized. One still unidentified species resembling A. tessmannii is discussed.     

12种中国葱属植物的核型分析

采用细胞压片法,对采自中国西部的12种葱属植物的根尖有丝分裂中期进行了观察,其巾天蓝韭(A.cyaneum)、梭沙韭(Aforrestii)、昌都韭(A.changduense)、西川非(A.xichuanense)、野黄韭(A.rude)、野葱(A.chrysanthum)和真籽韭(A.eusperma)等7种植物的核型为首次报道.供试类群中,峨眉韭(A.omeiense)和多星韭(A.wallichii)的染色体基数分别为11和7,其余类群的染色体基数均为8.观察发现,随体杂合和多侪性现象在供试类群中很普遍.分析推测:(1)随体和倍性的变异在葱属某些类群的进化中可能起重要作用,随体的类型在葱属具有重要的分类意义;(2)多倍化和地下走茎的无性繁殖方式可能是天蓝韭(A.cyaneum)的进化策略;(3)西川韭(A.xichuanense)、野黄非(A.rude)和野葱(A.chrysanthum)有密切的亲缘关系;(4)真籽韭(A.eusperma)与多籽组在核型上有密切的亲缘关系.     

A maternal store of macroH2A is removed from pronuclei prior to onset of somatic macroH2A expression in preimplantation embryos

MacroH2A histones are variants of canonical histone H2A that are conserved among vertebrates. Previous studies have implicated macroH2As in epigenetic gene-silencing events including X chromosome inactivation. Here we show that macroH2A is present in developing and mature mouse oocytes. MacroH2A is localized to chromatin of germinal vesicles (GV) in both late growth stage (lg-GV) and fully grown (fg-GV) stage oocytes. In addition, macroH2A is associated with the chromosomes of mature oocytes, and abundant macroH2A is present in the first polar body. However, maternal macroH2A is lost from zygotes generated by normal fertilization by the late 2 pronuclei (2PN) stage. Normal embryos at 2-, 4-, and 8-cell stages lack macroH2A except in residual polar bodies. MacroH2A protein expression reappears in embryos after the 8-cell stage and persists in morulae and blastocysts, where nuclear macroH2A is present in both the trophectodermal and inner cell mass cells. We followed the loss of macroH2A from pronuclei in parthenogenetic embryos generated by oocyte activation. Abundant macroH2A is present upon the metaphase II plate and persists through parthenogenetic anaphase, but macroH2A is progressively lost during pronuclear decondensation prior to synkaryogamy. Examination of embryos generated by intracytoplasmic sperm injection (ICSI) revealed that macroH2A is associated exclusively with female pronuclei prior to loss in late pronucleus stage embryos. These results outline a surprising finding that a maternal store of macroH2A is removed from the maternal genome prior to synkaryogamy, resulting in embryos that execute three to four mitotic divisions in the absence of macroH2A prior to the onset of embryonic macroH2A expression.     

Genetic characterization of Artemia tibetiana (Crustacea: Anostraca)

The brine shrimp Artemia consists of a number of bisexual species and a large number of parthenogenetic forms, which collectively, inhabit a wide range of hypersaline habitats. A recently described species (A. tibetiana) from a carbonate lake (Lagkor Co) in Tibet at an altitude of 4490 m has been tested with New World (A. franciscana USA, and A. franciscana feral population Vietnam) and Old World species (A. salina, A. urmiana, A. sinica) for cross fertility. These tests show complete infertility between A. tibetiana and A. franciscana . Between A. tibetiana and A. urmiana, A. sinica partial fertility through to F₂ and F₃ generations is evident. Allozyme and RAPD comparison of A. tibetiana with A. franciscana (USA), A. franciscana (Vietnam), A. sinica (Mongolia) and A. urmiana (Iran) show that A. tibetiana is similar to other bisexual species in mean heterozygosity (0.074) but has a somewhat higher proportion of polymorphic loci (40%, similar to that of A. urmiana ). The genetic distance between A. tibetiana and A. franciscana is 0.730, between A. tibetiana and A. urmiana is 0.475 and that between A. tibetiana and A. sinica is 0.114. F_IS estimates for A. tibetiana differ significantly from zero for six loci, mainly because of lack of fit to Hardy-Weinberg expectations. This may suggest that even within the limited area of Lagkor Co there are Genétically distinct populations. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 333–344.     

中国黄耆属植物一些种类的订正

在对中国黄耆属植物进行研究的过程中,发现一些不同时期发表的类群存在同物异名现象。对这些类群进行了归并,将Astragalus dulanensis Y．H．Wu作为A．variabilis Bunge的新异名,A．hepingensis Liou f和A．mongutensis Lipsky作为A．kuschakewiczi B．Fedtsch ex O．Fedtsch的新异名,A．zhaolingicus K．T．Fu作为A．galactites Pall．的新异名,A．xipingshanicus Y．H．wu作为A．minshanensis K．T．Fu的新异名,A．transiliensis Gontsch.var．microphyllus S．B．Ho作为A．ochrias Bunge的新异名。     

横断山区四种湍蛙的细胞遗传学研究

通过染色体组型分析,C带(BSG技术)分析及一种简便的Ag-NORs带分析,对四川湍蛙、理县湍蛙、棕点湍蛙和棘皮湍蛙的种间关系、染色体的演化及其性染色体等问题进行了初步探讨。结果表明:(1)四川湍蛙、理县湍蛙和棕点湍蛙之间的亲缘关系较近,而它们与棘皮湍蛙的亲缘关系较远;(2)在近缘种的分化中,染色体结构异染色质的变化和臂间倒位是重要的因素之一,这在小型染色体上表现得尤为突出;(三)四川湍蛙具有在形态上分化很明显的性染色体。C带分析表明,此性染色体主要由常染色质构成,但在其Y染色体的长臂上存在明显的中间C带,推测尚处于性染色体分化的初期阶段。     

Acetylation regulates subcellular localization of eukaryotic translation initiation factor 5A (eIF5A)

Eukaryotic translation initiation factor 5A (eIF5A) is a protein subject to hypusination, which is essential for its function. eIF5A is also acetylated, but the role of that modification is unknown. Here, we report that acetylation regulates the subcellular localization of eIF5A. We identified PCAF as the major cellular acetyltransferase of eIF5A, and HDAC6 and SIRT2 as its major deacetylases. Inhibition of the deacetylases or impaired hypusination increased acetylation of eIF5A, leading to nuclear accumulation. As eIF5A is constitutively hypusinated under physiological conditions, we suggest that reversible acetylation plays a major role in controlling the subcellular localization of eIF5A.