高罗王冠虫（Coronocephalus gaoluoensis Wu, 1979）的再研究

标本采自湖南省永顺县万民乡志留系下部Llandovery统Telychian阶秀山组上部,几乎全部为Coronocephalus gaoluoensis Wu,其中有20多块头、胸、尾相连的完整标本。研究发现,Coronocephalus gaoluoensis Wu具有十分特殊的头部构造,其面线前支横切头鞍前叶中前部...     

灌浆期喷施6-BA对甜玉米一些生理指标的影响

甜玉米灌浆期喷施不同浓度6-BA后,叶片叶绿素含量、光合速率、比叶重均提高,丙二醛含量和外渗电导率明显降低,籽粒中可溶性糖和维生素C含量均提高.     

几种药物抑制马传染性贫血病毒和人免疫缺陷病毒的实验研究

用马传染性贫血病毒—驴胚肺二倍体细胞(EIAV-DELDC)为实验体系,以细胞中病毒逆转录酶活性及病毒相关抗原的表达为观察指标,检测了叠氮胸苷(AZT)、三氮唑核苷(Ribavirin,病毒唑)、磷羧基甲酸钠(PFA)和苏拉明等4种已知抗人免疫缺陷病毒(HIV-1)药物对马传染性贫血病毒的抑制作用。结果表明,PFA、AZTTP(三磷酸AZT)和苏拉明均能抑制病毒相关抗原的表达,AZT虽无此作用,但能抑制细胞内逆转录酶活性。用~3H-TMP掺入法比较了PFA、AZTTP、苏拉明对体外无细胞系EIAV逆转录酶粗提物和HIV-1基因工程产物逆转录酶活性的抑制作用表明,两种逆转录酶对苏拉明的敏感性相近,而HIV-1逆转录酶对PFA和AZTTP的敏感性较EIAV者高约100倍。又以无细胞系中逆转录酶活性测定法,检测了12种中药提取物的抑制作用,其中小柴胡汤对EIAV和HIV-1逆转录酶活性都有抑制作用,IC_(50)为717μg/ml和700μg/ml(生药浓度)。小柴胡汤对两种病毒感染细胞中抗原的表达和HIV引起细胞病变都有抑制作用,对HIV-1的抑制比EIAV强。这些结果表明,EIAV-DELDC体系可考虑作为抗HIV-1药物筛选模型。     

啮齿动物的贮藏行为与植物种子的扩散

绝大多数啮齿动物一方面取食大量的植物种子和果实,另一方面通过其贮食行为将植物种子和果实搬运到远离母树的地点,即扩散,并将它们分散埋藏在落叶下或浅表的土层中,从而影响种子和果实的时空分布,最后导致幼苗在有利的条件下发生和建成,实现植物更新。啮齿动物与植物种子和果实之间已广泛形成了互惠或协同进化的关系。啮齿动物的贮食行为主要通过以下几个过程对植物种子和果实的扩散产生影响：选择、搬运和埋藏以及随后对种子和幼苗存活和死亡的影响等。本综述了啮齿动物对植物种子和果实贮藏的研究结果,以期为进一步开展啮齿动物的贮食行为在植物种子和果实的扩散中的作用的研究提供参考。     

Generation of Hepatitis B virus PreS2-S antigen in Hansenula polymorpha

Despite the long availability of a traditional prophylactic vaccine containing the HBV surface antigen(HBsA g) and aluminum adjuvant, nearly 10% of the population remains unable to generate an effective immune response. Previous studies have indicated that hepatitis B virus(HBV) PreS 2-S is abundant in T/B cell epitopes, which induces a stronger immune response than HBsA g, particularly in terms of cytotoxic T lymphocyte(CTL) reaction. In the current study, the HBV PreS 2-S gene encoding an extra26 amino acids(PreS 2 C-terminus) located at the N-terminus of HBsA g was cloned into the pV CH1300 expression vector. Pre S2-S expressed in the methylotrophic yeast, Hansenula polymorpha, was produced at a yield of up to 250 mg/L. Subsequent purification steps involved hydrophobic adsorption to colloidal silica, ion-exchange chromatography and density ultracentrifugation. The final product was obtained with a total yield of ~15% and purity of ~99%. In keeping with previous studies, ~22 nm viruslike particles were detected using electron microscopy. The generated PreS 2-S antigen will be further studied for efficacy and safty in animals.     

人参生理生态的研究

人参是我国极其珍贵的药用植物之一。本文从生理生态的角度对其在生长季的各种环境因子的变化规律及光合生理进程作了较为全面、系统的定位定量研究。根据不同观测点的试验数据,得出了有利于人参生长的最适环境范围,为人参的栽培提供了理论依据及基础资料。     

滑刃属一新种记述(滑刃目,滑刃科)

2002年从山东省乳山市牛筋草的根际土壤中发现滑刃属1新种,类刷尾滑刃线虫 Aphelenchoides parabrushmucronatus sp.nov,.该虫具有以下特征:雌虫虫体中等;唇区较高,缢缩明显;中食道球卵圆形;生殖系统发育良好,卵母细胞单列,受精囊和后阴子宫囊都含较大的圆形精子;雌虫尾圆柱形,尾端中间具有1试管刷状尾尖突.A.appendurus Singh,1967在形态上与新种相似,区别在于前者有两条侧线,虫体和口针更长,尾巴相对较短(L=720-880μm;stylet=16～17μm;tail=38.4μm).A.seiachicus Nesterov,1973在形态上也与新种相似,区别在于前者虫体更小,口针、尾巴更短(L=370-420μm;stylet=9.5μm;c'=3).     

成年大鼠海马CA1区锥体细胞KATP通道的特性

为了解成年大鼠海马CA1区锥体细胞KATP通道的特性,实验采用膜片钳技术的内面向外式记录法,在急性分离的CA1区锥体神经元上,研究了可被胞浆侧ATP所抑制的钾离子单通道的特性,当细胞膜内外两侧的K^ 浓度均为140mmol/L时,通道的电导为63pS,翻转电位为1．71mV,通道呈弱向内向整流性,在负钳制电位时,通道开放时常被短时的关闭所打断,而在正钳制电位时,这种短时程的关闭状态明显少于负钳制电位时,但通道开放概率未见明显的电压依赖性,ATP对通道活动的抑制作用呈浓度依赖性,抑制通道活动50％的ATP浓度为0．1mmol/L.KATP通道的特异性阻断剂tolbutamide(甲糖宁,1mmol/L)可完全阻断通道的活动,而KATP通道开放剂diazoxide(二氮嗪,1mmol/L）则不增强通道的活动。     

Multiple strategies to improve sensitivity,speed and robustness of isothermal nucleic acid amplification for rapid pathogen detection

Background  

In the past decades the rapid growth of molecular diagnostics (based on either traditional PCR or isothermal amplification technologies) meet the demand for fast and accurate testing. Although isothermal amplification technologies have the advantages of low cost requirements for instruments, the further improvement on sensitivity, speed and robustness is a prerequisite for the applications in rapid pathogen detection, especially at point-of-care diagnostics. Here, we describe and explore several strategies to improve one of the isothermal technologies, helicase-dependent amplification (HDA).     

Horizontal Transfer of Archaeal Genes into the Deinococcaceae: Detection by Molecular and Computer-Based Approaches

Members of the Deinococcaceae (e.g., Thermus, Meiothermus, Deinococcus) contain A/V-ATPases typically found in Archaea or Eukaryotes which were probably acquired by horizontal gene transfer. Two methods were used to quantify the extent to which archaeal or eukaryotic genes have been acquired by this lineage. Screening of a Meiothermus ruber library with probes made against Thermoplasma acidophilum DNA yielded a number of clones which hybridized more strongly than background. One of these contained the prolyl tRNA synthetase (RS) gene. Phylogenetic analysis shows the M. ruber and D. radiodurans prolyl RS to be more closely related to archaeal and eukaryal forms of this gene than to the typical bacterial type. Using a bioinformatics approach, putative open reading frames (ORFs) from the prerelease version of the D. radiodurans genome were screened for genes more closely related to archaeal or eukaryotic genes. Putative ORFs were searched against representative genomes from each of the three domains using automated BLAST. ORFs showing the highest matches against archaeal and eukaryotic genes were collected and ranked. Among the top-ranked hits were the A/V-ATPase catalytic and noncatalytic subunits and the prolyl RS genes. Using phylogenetic methods, ORFs were analyzed and trees assessed for evidence of horizontal gene transfer. Of the 45 genes examined, 20 showed topologies in which D. radiodurans homologues clearly group with eukaryotic or archaeal homologues, and 17 additional trees were found to show probable evidence of horizontal gene transfer. Compared to the total number of ORFs in the genome, those that can be identified as having been acquired from Archaea or Eukaryotes are relatively few (approximately 1%), suggesting that interdomain transfer is rare.