内蒙古自治区螽亚目(Tettigoniodea,Orthoptera)昆虫区系及地带性分布的研究

内蒙古自治区目前共知螽亚目昆虫5科、26属、58种(表1)。其中螽斯占总种数的74.2％,蟋蟀占17.3％,其余的占7.5％。其区系组成以古北种为主体,特别是东北中国种、东西伯利亚——蒙古种和欧洲——西伯利亚种是区系组成的核心(表2)。特有种占有一定的比例(10.3％),主要分布于该区东北部的森林草原亚带和西部的荒漠带。中部地区有部分华北种的渗入。在本区东部的草原带中,螽斯亚科昆虫最为丰富;西部的荒漠带中,硕螽亚科昆虫是最突出的代表种,并有中亚种的分布(表4)。从总的种类分布来看,东北部的森林带和草原带的昆虫种类明显比西部荒漠带要丰富,中部的干草原亚带则是上述两者的过渡区域。 文中还根据螽亚目昆虫在不同植被地区的分布情况,采用Sφgrensen系数比较了各地带之间昆虫区系的相似性(表3)。用聚类分析的方法将10个植被地带或亚带划分成6个大的地带区:森林区、草原区、荒漠区、暖温型森林草原区、暖温型典型草原区和暖温型荒漠草原区(图2)。作者详细地叙述了各个地带区中昆虫区系的组成特点和分布规律。并就前人对该区昆虫区划工作提出了若干修订意见。     

含甲肝病毒基因的重组痘苗病毒在动物体内产生针对甲肝病毒的中和抗体

用DNA重组技术得到的含甲肝病毒基因的重组痘苗病毒,可在家兔体内产生ELISA竞争抑制与中和抗体。基础免疫后,动物体内竞争抑制抗体滴度为10,加强免疫后达到80。由重组病毒产生的抗体中和指数比甲肝病毒产生者略低。     

Survival of genetically engineered Escherichia coli in natural soil and river water

Twelve derivatives of Escherichia coli strain HB101 which contained different sizes of plasmids ranging from 3.9 Kb to 48 Kb and encoding resistance to various antibiotics were used. When these organisms were introduced into natural river water, the population declined rapidly and by day 3, the majority (i.e. more than 99.9%) of them could no longer be detected on antibiotic-amended culture plates. If the river water was filter sterilized first, the added organisms maintained their population for up to 7 d without any significant decrease in numbers. Similar results were also observed in sterilized tap water or distilled water. This indicated that the disappearance of these organisms in the aquatic environment was caused mainly by biotic factor(s). The loss of the ability to grow in the presence of antibiotics by some of the E. coli was not observed unless they were allowed to grow in the antibiotic-free environment first. When the test organisms were added to natural silt loam, a large portion of the original population still remained viable after 16 d. There was no relationship between the percentage survival of E. coli in natural river water and the sizes of plasmid harboured. On the other hand, when these bacteria were added to natural soil, survival appeared to increase as plasmid size increased. and accepted 19 August 1989     

紫云英根瘤菌109菌株吸氢的诱导表达——核苷、核苷酸与烟酸的促进效应

核苷酸和烟酸的添加,使紫云英根瘤菌109氢酶吸氢活性表达增加。cAMP(1 mmol/L),烟酸(70 mmol/L)的存在,缓解了葡萄糖酸钠或果糖引起的吸氢活性阻遏,cAMP的解阻遏效应在年轻的菌体(48 h)表现较为明显。但以MB为受体的破碎细胞吸氢活性则未见增加,烟酸的促进效应受到氯霉素(40μg/ml)的抑制。其他核苷或核苷酸,如腺嘌呤,尿嘧啶,ATP,ADP,AMP,UMP,UTP都能促进吸氢活性的表达。诱导氢酶前,细胞ATP库已处于低水平,并保持稳定,添加琥珀酸盐后,ATP库水平提高,吸氢活性表达受抑。     

PHA激活的脐血T细胞条件培养液对人骨髓CFU-c的抑制

本文研究了PHA刺激18小时收获的脐血T细胞条件培养液(PHA-TCM)对正常人骨髓CFU-c的影响。结果显示PHA-TCM能够显著抑制CFU-c的生长,这种抑制与PHA-TCM浓度有关。并发现经PHA-TCM作用后M型集落比例明显降低。PHA-TCM中未检出IFN和IL-2活性。进一步研究证实,PHA-TCM中CFU-c抑制活性是一种对酸碱敏感对热相对不敏感的蛋白质,其分子量大于10,000道尔顿。     

Genetic mapping indicates that VP4 is the rotavirus cell attachment protein in vitro and in vivo.

To identify the rotavirus protein which mediates attachment to cells in culture, viral reassortants between the simian rotavirus strain RRV and the murine strains EHP and EW or between the simian strain SA-11 and the human strain DS-1 were isolated. These parental strains differ in the requirement for sialic acid to bind and infect cells in culture. Infectivity and binding assays with the parental and reassortant rotaviruses indicate that gene 4 encodes the rotavirus protein which mediates attachment to cells in culture for both sialic acid-dependent and -independent strains. Using ligated intestinal segments of newborn mice and reassortants obtained between the murine strain EW and RRV, we developed an in vivo infectivity assay. In this system, the infectivity of EW was not affected by prior treatment of the enterocytes with neuraminidase, while neuraminidase treatment reduced the infectivity of a reassortant carrying gene 4 from RRV on an EW background more than 80% relative to the controls. Thus, VP4 appears to function as the cell attachment protein in vivo as well as in vitro.     

The use of isotope tracers for identifying populations of migratory birds

 To determine whether stable isotopes can be used for identifying the geographic origins of migratory bird populations, we examined the isotopic composition of hydrogen (deuterium, δD), carbon (δ¹³C), and strontium (δ⁸⁷Sr) in tissues of a migratory passerine, the black-throated blue warbler (Dendroica caerulescens), throughout its breeding range in eastern North America. δD and δ¹³C values in feathers, which are grown in the breeding area, varied systematically along a latitudinal gradient, being highest in samples from the southern end of the species’ breeding range in Georgia and lowest in southern Canada. In addition, δD decreased from east to west across the northern part of the breeding range, from New Brunswick to Michigan. δ⁸⁷Sr ratios were highest in the Appalachian Mountains, and decreased towards the west. These patterns are consistent with geographical variation in the isotopic composition of the natural environment, i.e., with that of precipitation, plants, and soils for δD, δ¹³C, and δ⁸⁷Sr, respectively. Preliminary analyses of the δD and δ¹³C composition of feathers collected from warblers in their Caribbean winter grounds indicate that these individuals were mostly from northern breeding populations. Furthermore, variances in isotope ratios in samples from local areas in winter tended to be larger than those in summer, suggesting that individuals from different breeding localities may mix in winter habitats. These isotope markers, therefore, have the potential for locating the breeding origins of migratory species on their winter areas, for quantifying the degree of mixing of breeding populations on migratory and wintering sites, and for documenting other aspects of the population structure migratory animals – information needed for studies of year-round ecology of these species as well as for their conservation. Combining information from several stable isotopes will help to increase the resolution for determining the geographic origins of individuals in such highly vagile populations. Received: 24 April 1995 / Accepted: 2 June 1996     

Effects of sound direction on the processing of amplitude-modulated signals in the frog inferior colliculus

Single-unit recordings were made from 143 neurons in the frog (Rana p. pipiens) inferior colliculus (IC) to investigate how free-field sound direction influenced neural responses to sinusoidal-amplitude-modulated (SAM) tone and/or noise. Modulation transfer functions (MTFs) were derived from 3 to 5 sound directions within 180° of frontal field. Five classes of MTF were observed: low-pass, high-pass, band-pass, multi-pass, and all-pass. For 64% of IC neurons, the MTF class remained unchanged when sound direction was shifted from contralateral 90° to ipsilateral 90°. However, the MTFs of more than half of these neurons exhibited narrower bandwidths when the loudspeaker was shifted to ipsilateral azimuths. There was a decrease in the cut-off frequency for neurons possessing low-pass MTFs, an increase in cut-off frequency for neurons showing high-pass MTFs, or a reduction in the pass-band for neurons displaying bandpass MTFs. These results suggest that sound direction can influence amplitude modulation (AM) frequency tuning of single IC neurons.Since changes in periodicity of SAM tones alter both the temporal parameters of sounds as well as the sound spectrum, we examined whether directional effects on spectral selectivity play a role in shaping the observed direction-dependent AM selectivity. The directional influence on AM selectivity to both SAM tone and SAM noise was measured in 62 neurons in an attempt to gain some insight into the mechanisms that underlie directionally-induced changes in AM selectivity. Direction-dependent changes in the shapes of the tone and noise derived MTFs were different for the majority of IC neurons (55/62) tested. These data indicate that a spectrally-based and a temporally-based mechanism may be responsible for the observed results.Abbreviations AM amplitude modulation - CF characteristic frequency - DI direction index - FR isointensity frequency response - GABA gamma-aminobutyric acid - IC inferior colliculus - ICc central nucleus of the inferior colliculus - ITD interaural time difference - MTF modulation transfer function - PSTH peri-stimulus time histogram - SAM sinusoidal-amplitude-modulated - SC synchronization coefficient - CN cochlear nucleus     

白细胞介素－2中枢镇痛作用途径的探讨

抗ＩＬ－２受体α亚基的单克隆抗体不能阻断ＩＬ－２的中枢镇痛作用,以及丧失与ＩＬ－２受体β亚基结合能力的ＩＬ－２突变体仍具有提高大鼠痛阈的能力,这表明ＩＬ－２的中枢镇痛作用并不是通过ＩＬ－２受体所介导,亦表示ＩＬ－２的免疫和镇痛作用是通过不同的受体途径实现的。加之内源性阿片肽与ＩＬ－２分子有着共同的抗原决定基和结构相似性,提示ＩＬ－２可以与阿片受体直接结合产生中枢镇痛效应。从放射免疫法测定的ＩＬ－２侧脑室注射后不同时间大鼠脑内不同核团的内源性阿片肽含量,推测ＩＬ－２的中枢镇痛作用可能还与弓状核、室旁核、蓝斑等核团的β－ＥＰ和ＬＥＫ有关。     

华北棉区夏播棉田害虫发生特点分析

分析和比较了华北棉区夏季播种与春季播种的棉田主要害虫（棉铃虫与棉蚜）的发生特点,探讨了它们的管理对策。