中国栅蛛属2新种记述(蜘蛛目:栅蛛科)

本文记了分别采自云南高黎贡山的栅蛛科栅蛛属Hahnia 2新种:垭口栅蛛,新种S.yakouensis sp.nov.和肾形栅蛛,新种S.reniformis sp.nov..垭口栅蛛后眼列前曲,交媾腔大,扁圆形,交媾孔1个,位于交媾腔下缘,交媾管粗,呈"人"字形下行分成2支再向两侧扭曲.纳精囊有一肓管斜向上伸出,鉴于上述特征而与Hahnia mridulae Tikader,1970不同.肾形栅蛛交媾孔2个,位于生殖厣腹面中央,纳精囊1对,大,肾形,插入器始于生殖球左下方,鉴于上述特征而与Hahnia xinjiangensis Wang et Liang,1989不同. Abstract： The present paper deals with two new species of the genus Hahnia collected from the Gaoligong Mountains Region of Yunnan Province, China: Hahnia yakouensis sp. nov., Hahnia reniformis sp. nov..     

注重发挥博士后科研生力军作用

中国医科大学博士后科研流动站始建1995年。目前学校设有基础医学、临床医学和生物学3个博士后科研流动站。但由于每年国家财力有限,资助名额很少,在有限条件下建立、健全博士后制度,加强对博士后人员的培养,调动博士后人员的积极性是一项重要的研究课题。     

遗传物质的发现者之一——麦卡锡

1944年,3位科学家艾弗里、麦卡锡和麦克劳德在DNA遗传本质方面的发现是20世纪最重要的发现之一,这个发现打开了生物学革命的大门,从而改变了人类对自然界的看法,这项研究还为1953年沃森和克里克DNA双螺旋结构的发现奠定了坚实的基础,但不幸的是3位科学家都未曾荣获诺贝尔奖.通过介绍麦克林·麦卡锡的科学研究,从而对这项发现的基本状况有一个基本的了解.     

生命之树与进化模式:导言

One and half centuries ago, Charles Darwin (1859) presented overwhelming evidence and argued that all life on the earth shared common descent, and "from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved". Ernst Haeckel (1886) and several of his contemporaries attempted to trace the pattern of descent among all extant and extinct forms in what Darwin referred to as "the great Tree of Life". Ever since then, systematists and evolutionary biologists have been exploring morphological, cytogenetic, chemical, developmental and molecular characters, and actively developing theories and methods to infer phylogenetic relationships among organisms from these characters. This endeavor has been especially stimulated by the rise of molecular biology and the emergence of computer science over the past 50 years. At the beginning of the 21st century, we are presented with an unprecedented opportunity to reconstruct the entire Tree of Life, and further, to study evolutionary processes and mechanisms in the context of a robust phylogenetic framework.     

我国微生态学的奠基人——魏曦

魏曦,字东升,1903年12月25日出生于湖南岳阳一个小职员家庭,父亲任职于邮政局.1914～1921年他在家乡湖滨中学读书,毕业后考入长沙湘雅医学院,学习两年后曾参加北伐军,任第四集团军警卫团三等军医.后退出军队,在长沙广雅中学任教.1928年入设立在上海的中央大学医学院(1932年独立为上海医学院)学习,1933年毕业,获博士学位.     

高黎贡山北段东西坡种子植物区系的比较研究

高黎贡山北段的东西坡由于在降雨量和热量分配等方面存在着显著的差异,致使东西坡在植物的种类、组成及区系特征等方面表现出明显的差异.东坡记载野生种子植物152科,580属,1475种及192变种(亚种),西坡记载野生种子植物162科,659属,1804种及186变种(亚种).东西坡种子植物科、属、种的对比分析表明:1)东西坡现代种子植物区系具有相同的历史渊源,但其区系联系减弱了,东西坡区系相似性程度,依科、属、种的顺序依次递减;2)西坡现代种子植物区系比东坡具有更为深刻的热带起源烙印.就科、属、种三个水平来说,东坡的热带成分低于西坡,温带成分高于西坡.许多典型的泛热带大科在西坡比东坡有着更为丰富的种类,其中有些泛热带科分子在东坡缺乏分布,而在西坡找到了合适的驻留之地;3)西坡现代种子植物区系与东喜马拉雅植物区系的联系比东坡紧密,而东坡与高黎贡山以东的区系联系比西坡密切,由于高黎贡山山脉的阻隔,近代植物物种的东西坡交流发生了障碍;4)西坡生态地理环境比东坡更有利于物种的生存、繁衍和分化,它既是古老成分的避难所,又是孕育新生成分的摇篮.     

用叶绿体ndhF和核核糖体ITS序列推断李属(蔷薇科)的系统发育

Sequences of the chloroplast ndhF gene and the nuclear ribosomal ITS regions are employed to reconstruct the phylogeny of Prunus (Rosaceae), and evaluate the classification schemes of this genus. The two data sets are congruent in that the genera Prunus s.l. and Maddenia form a monophyletic group, with Maddenia nested within Prunus. However, the ndhF data set is incongruent with the ITS data supporting two major groups within Prunus one consisting of subgenera Laurocerasus (including Pygeum) and Padus as well as the genus Maddenia and another of subgenera Amygdalus, Cerasus, and Prunus. The ITS data, on the other hand, support a clade composed of subgenera Amygdalus and Prunus and Prunus sect. Microcerasus in addition to a paraphyletic grade of subgenera Laurocerasus and Padus (and the genus Maddenia) taxa. In general, the subgeneric classifications of Prunus s.l. are not supported. The ITS and ndhF phylogenies differ mainly in interspecific relationships and the relative position of the Padus/Laurocerasus group. Both ITS and ndhF data sets suggest that the formerly recognized genus Pygeum is polyphyletic and that the distinction of the subgenera Padus and Laurocerasus is not supported. The biogeographic interactions of the temperate and tropical members in the Padus/Laurocera- sus/Maddenia alliance including Pygeum are shown to be highly dynamic and complex.     

途经甘肃的3种水鸟新纪录

2007年10月13日至11月5日进行敦煌市湿地鸟类调查时,分别在南湖湿地与候鸟自然保护区及党河水库使用Leica apo77高倍望远镜观察到3种水鸟,在以往的文献资料中未见其分布于甘肃的报道,应为甘肃鸟类新纪录。笔者用500mm镜头分别拍下3种水鸟的照片。1.赤颈(Podiceps grisegena)2007年10月13日13:30时,在南湖湿地与候鸟自然保护区的阳关水库(渥洼池)记录到2只赤颈。当时水面上同时有凤头(P.cristatus)、黑颈(P.nigricollis)以及大量鸭类、潜鸭类游禽活动,赤颈体形较凤头小,而又明显比黑颈大。其中一只赤颈的…     

鸡的瞬膜

瞬膜(nictitating membrane),又称第三眼睑,是一种保护眼球、防止灰尘的结构.鸟类的瞬膜位于眼眶的前眼角,为半透明的膜,其内缘具有一种羽毛上皮,借以刷洗角膜上的灰尘.在飞行时能遮覆眼球,以避免干燥气流和灰尘对眼球的伤害.由于瞬膜在鸟类睁眼的一瞬间迅速缩回前眼角,很难拍摄到.最近费了好大的周折,终于拍到了理想的鸡瞬膜照片,现予以发表供生物学界的同行共享(友情提示:如引用请注明原作者).     

人粒细胞集落刺激因子cDNA的克隆、序列鉴定及初步表达

利用多聚酶链反应技术,从人膀胱癌细胞系5637细胞中快速扩增并克隆了人粒细胞集落刺激因子cDNA,序列分析证明,该cDNA包含人粒细胞集落刺激因子的全部编码基因,全长612bp,编码30个氨基酸的信号肽和174个氨基酸的成熟蛋白。其中第43位codon出现一个碱基的突变(CAC→TAC)导至第43位氨基酸的改变(组氨酸→酪氨酸)。经逆转录病毒导入SP2/0细胞并初步表达。结果表明:该基因产物具有G-CSF活性。     

An inhibitor of collagen-stimulated platelet activation from the salivary glands of the Haementeria officinalis leech. II. Cloning of the cDNA and expression.

Salivary glands of the leech Haementeria officinalis contain a protein, leech antiplatelet protein (LAPP), that specifically blocks collagen-mediated platelet aggregation (Connolly, T. M., Jacobs, J. W., and Condra, C. (1992) J. Biol. Chem. 267, 6893-6898). Degenerate oligonucleotides whose sequences were derived from two short peptides from V8 digests of the native LAPP were used as primers to generate a polymerase chain reaction (PCR) product which contains the cDNA region coding for the sequence between these two peptides. Using this PCR product as a hybridization probe, phage containing cDNA clones were isolated containing the entire deduced amino acid sequence for LAPP. Computer analysis of the amino acid sequence predicts a peptidase cleavage site between a 21-residue pre-peptide and a mature protein of 126 amino acids. A DNA insert to express the predicted mature LAPP protein was generated by PCR amplification using phage-derived cDNA clones as a substrate. This insert encoded a fusion protein with the leader sequence of the yeast alpha mating factor and the mature LAPP cDNA. These PCR products were cloned into the yeast expression vector pKH4 alpha 2. A KEX 2 Lys-Arg endopeptidase cleavage site was placed NH2-terminal to the predicted mature protein. This vector transfected into the yeast Saccharomyces cerevisiae directs expression of a secreted mature protein at levels up to 200 mg of LAPP/liter of culture medium. The recombinant protein was comparable to native LAPP in its electrophoretic mobility, its reactivity with anti-LAPP antisera, and its biological activity including inhibition of collagen-stimulated platelet aggregation and the adhesion of platelets to collagen. Availability of significant quantities of recombinant LAPP opens the way to further biochemical structure/function studies and to studies on the effects of an inhibitor of collagen-stimulated platelet aggregation in vivo.     

Molecular characterization of tomato fruit polygalacturonase

Summary Using the expression vector gt11 and immunological detection, cDNA clones of an endopolygalacturonase gene of tomato (Lycopersicon esculentum Mill.) were isolated and sequenced. The 1.6 kb cDNA sequence predicts a single open reading frame encoding a polypeptide of 457 amino acids. The PG2A isoform of tomato fruit endopolygalacturonase was purified and 80% of the amino acid sequence determined. The amino acid sequence predicted by the cDNA sequence was identical to the amino acid sequence of the PG2A isoform. The position of the codon for the N-terminal amino acid of mature PG2A in the open reading frame indicates the presence of a 71 amino acid N-terminal signal peptide which is post-translationally processed. The C-terminus of purified PG2A occurred 13 amino acids before the stop codon in the cDNA suggesting that C-terminal processing of PG2A may also occur. The nucleotide and amino acid sequence data predict a mature protein of 373 amino acids and a polypeptide molecular weight of 40279. The sequence contains four potential glycosylation sites. Northern analysis detected endopolyga-lacturonase mRNA in stage 3 (turning) and stage 6 (red) ripening fruit, but not in leaves, roots, or green fruit of normal cultivars or in mature fruit of the rin mutant.     

Nuclear-encoded chloroplast ribosomal protein L12 of Nicotiana tabacum: characterization of mature protein and isolation and sequence analysis of cDNA clones encoding its cytoplasmic precursor.

Poly(A)+ mRNA isolated from Nicotiana tabacum (cv. Petite Havana) leaves was used to prepare a cDNA library in the expression vector lambda gt11. Recombinant phage containing cDNAs coding for chloroplast ribosomal protein L12 were identified and sequenced. Mature tobacco L12 protein has 44% amino acid identity with ribosomal protein L7/L12 of Escherichia coli. The longest L12 cDNA (733 nucleotides) codes for a 13,823 molecular weight polypeptide with a transit peptide of 53 amino acids and a mature protein of 133 amino acids. The transit peptide and mature protein share 43% and 79% amino acid identity, respectively, with corresponding regions of spinach chloroplast ribosomal protein L12. The predicted amino terminus of the mature protein was confirmed by partial sequence analysis of HPLC-purified tobacco chloroplast ribosomal protein L12. A single L12 mRNA of about 0.8 kb was detected by hybridization of L12 cDNA to poly(A)+ and total leaf RNA. Hybridization patterns of restriction fragments of tobacco genomic DNA probed with the L12 cDNA suggested the existence of more than one gene for ribosomal protein L12. Characterization of a second cDNA with an identical L12 coding sequence but a different 3'-noncoding sequence provided evidence that at least two L12 genes are expressed in tobacco.     

Activin B: precursor sequences, genomic structure and in vitro activities

We report here the complete amino acid sequence of the human inhibin beta B-subunit as deduced from the sequence of cDNA and genomic clones. The primary translation product of the beta B mRNA predicts a protein of 407 amino acids, containing a prepro region of 292 amino acids separated by basic amino acids from the mature C-terminal 115 amino acids. Mammalian tissue culture cells transfected with a beta B-subunit expression plasmid secreted an activin B homodimer of approximately 22K mol wt. Coexpression of the beta A- and beta B-subunit mRNAs resulted in the secretion of the three forms of activin, A, AB, and B. Purified activin B was shown to elicit FSH release in an in vitro pituitary assay and trigger the accumulation of hemoglobin in K562 cells. The potency of activin B in both of these assays (ED50 approximately 2 ng/ml) was indistinguishable from that observed for activin A.     

Molecular cloning and characterization of a novel rat CXC chemokine, rPBP, the homologue of human and mouse PBP

We have previously cloned the mouse platelet basic protein (mPBP), a homologue of human PBP, from mouse thymic stromal cells. Using EST alignment and RT-PCR, the rat homologue of human and mouse PBP was cloned from lung and named as rPBP. The complete open reading frame and part of the 3'- and 5'-non-coding regions were obtained through rapid amplification of cDNA ends. The rPBP cDNA encodes a protein of 111 amino acids containing a signal peptide of 37 amino acids at the N-terminus, with the mature protein of 74 amino acids. The rPBP is a new member of ELR+CXC chemokines. The mature protein of rPBP shares 69% and 45% homology with mouse and human PBP, respectively. In situ hybridization assay revealed rPBP to be predominantly localized in the pulmonary vascular endothelial cells. The eukaryotic expression vector pCDNA3-rPBP was constructed and transiently transfected into COS-7 cells. In the in vitro chemotaxis assay, the polymorphonuclear leukocytes (PMNs) were chemoattracted to the supernatants from transfected COS-7 cells in a dose-dependent manner. The implication of rPBP found in rat lung is that this chemokine may have the function to recruit PMNs to fight against pulmonary infection.     

Porcine interleukin 18: cloning, characterization of the cDNA and expression with the baculovirus system

We have isolated and sequenced a cDNA that contains the coding sequence of porcine interleukin 18 (IL-18) and the recombinant protein of porcine IL-18 was expressed using the baculovirus system. The open reading frame (ORF) of the porcine IL-18 cDNA is 579 base pairs (bp) in length and encodes 192 amino acids. The predicted amino acid sequence is 76.7%, 64.7% and 61.6% homologous to the predicted human, murine and rat amino acid sequences, respectively. The porcine precursor and mature IL-18 protein were expressed respectively in Trichoplusia ni -derived (Tn5) cells using the baculovirus Autografha californica nuclear polyhedorosis virus (AcNPV) as a vector. Tn5 cells infected with recombinant virus containing a whole IL-18 protein coding region sequence secreted porcine precursor IL-18 into the culture medium. On the other hand, Tn5 cells infected with recombinant virus containing a mature IL-18 protein coding region sequence expressed several proteins in the cell lysates, but did not secrete mature protein into the culture medium efficiently. Immunoblotting analysis of recombinant protein showed cross-reactivity with anti-human IL-18 polyclonal antibody. The mature form of porcine IL-18 protein induced IFN-gamma production in suboptimal doses of anti-CD3 antibody and concanavalin A- (ConA) stimulated porcine peripheral blood mononuclear cells (PBMC), but the precursor form had little effect.     

Primary structure of the nuclear-encoded 29.9 kDa subunit of NADH: ubiquinone reductase from Neurospora crassa mitochondria.

We isolated and sequenced cDNA for the 29.9 kDa subunit of mitochondrial NADH: ubiquinone reductase (complex I) from a Neurospora crassa library in the lambda gt11 expression vector. The N-terminus of the mature protein was determined by Edman-degradation. The cDNA contains an open reading frame encoding a preprotein of 273 amino acids. The presequence of the transit protein essential for mitochondrial import is eight residues long. Northern-blot analysis shows, that the level of the corresponding mRNA is increased 3-fold if cells are grown in the presence of chloramphenicol.     

Cloning, sequencing and expression of human TSH receptor

Complementary cDNA clones encoding the TSH (thyroid stimulatory hormone) receptor were isolated from a human thyroid lambda gt10 library using Iow stringency hybridization with LH/hCG (luteinizing hormone-human choriogonadotropic hormone) receptor probes. Sequencing of the clones showed a 764 amino acid open reading frame. The first 21 amino acids probably correspond to a signal peptide, the mature protein thus contains 743 amino acids (calculated molecular weight: 84,501 daltons). Its putative structure consists of a 394 amino acid extracellular domain, a 266 amino acid membrane spanning domain with 7 putative transmembrane segments and a 83 amino acid intracellular domain. A high degree of homology is observed with LH/hCG receptor suggesting the definition of a new subfamily of G-protein coupled receptors. Computer search showed the presence in the putative third intracellular loop of a motif resembling that described in the non receptor type protein tyrosine kinases (c-src, c-yes, c-fgr, etc...). RNA blots showed that the receptor messenger RNA consists of two major species of 4300 and 3900 nucleotides. The cDNA was inserted into an expression vector and after transfection into COS 7 cells it was shown to produce a functional TSH receptor.     

白鹅催乳素基因的克隆及诱导表达条件的优化

摘要: 运用RT-PCR方法, 从白鹅脑垂体总RNA中扩增得到了催乳素(Prolactin, PRL)基因编码区序列cDNA, 并将其克隆到pMD18-T载体上。DNA序列分析表明, PRL cDNA包括终止密码子在内的长度为690 bp,编码230个氨基酸残基的蛋白质, 与皖西白鹅的有所差异, 二者碱基同源性在99.57%, 氨基酸同源性达99.56%。将PRL基因编码区序列cDNA定向克隆到表达载体pET-32a (+)中, 构建表达质粒pET-32a(+)-PRL。该质粒的BL21 (DE3)转化菌在IPTG的诱导下可表达PRL基因融合蛋白, IPTG终浓度1 mmol/L, 37℃, 诱导4 h表达量最高, 表达量约占菌体总蛋白的28.96%。