Analysis of the replication region of a mycobacterial plasmid, pMSC262.

We determined the nucleotide sequence of a DNA fragment which contains the replication region of pMSC262, a Mycobacterium scrofulaceum plasmid used to construct the Mycobacterium-Escherichia coli shuttle vector. The complete sequence of the fragment contained 2,504 bp with an overall G+C content of 69.8%. By deletion analysis, we found that the minimum length required for plasmid replication in M. bovis BCG was about 1.6 kb. Within this region, several open reading frames (ORFs) and a putative replication origin (ori) were identified by computer analysis. One of the ORFs, ORF2, which encodes a putative 28.9-kDa basic protein with characteristics of DNA-binding proteins, appeared to be involved in replication of the plasmid in BCG. By separation of ORF2 and the putative ori region, it was revealed that the relative locations of ORF2 and the putative ori region are likely important for replication in BCG. No DNA or amino acid homologies were found between this replication region and that of pAL5000, another mycobacterial plasmid used for vector plasmid construction. In addition, we found that this replicon did not lead to replication in E. coli and was compatible in BCG with pAL5000-derived vector plasmid pYUB75 (R. G. Barletta, D. D. Kim, S. B. Snapper, B. R. Bloom, and W. R. Jacobs, J., J. Gen. Microbiol. 138:23-30, 1992).     

华中冬青化学成分的研究

从华中冬青（Ｉｌｅｘ ｃｅｎｔｒｏｃｈｉｎｅｎｓｉｓ Ｓ．Ｙ．Ｈｕ）的叶片分离到９ 种黄酮类化合物：１ 种新化合物鉴定为３,５,５,７－四羟基二氢黄酮,命名为华中冬青黄酮（Ⅰ）;８ 种化合物鉴定为柚皮素（Ⅱ）、橙皮素（Ⅲ）、异樱花素（Ⅳ）、枸柑甙（Ⅴ）、橙皮甙（Ⅵ）、洋芹素（Ⅶ）、紫云英甙（Ⅷ）和野漆树甙（Ⅸ）。它们皆首次从该植物分得     

刺果番荔枝中的番荔枝内酯

从刺果番荔枝（Ａｎｎｏｎａ ｍ ｕｒｉｃａｔａ Ｌ．）的种子中分离到３ 个单四氢呋喃型番荔枝内酯类化合物,用波谱方法鉴定为海南哥纳香甲素（ｈｏｗ ｉｉｃｉｎ Ａ, Ｓ１３）、乙素（ｈｏｗ ｉｉｃｉｎ Ｂ, Ｓ５）和新化合物４－去氧海南哥纳香乙素（４－ｄｅｓｏｘｙｈｏｗ ｉｉｃｉｎ Ｂ, Ｓ２）。     

pCMBS对完整红细胞膜阴离子通透性的影响

根据等渗ＮＨ４Ｃｌ溶血动力学,探讨了ｐＣＭＢＳ（对氯汞苯磺酸）对完整红细胞膜阴离子通透性的影响．０．０５ｍｍｏｌ／ＬｐＣＭＢＳ使阴离子通透系数Ｐｃｌ下降为对照的８６．５％;１．０ｍｍｏｌ／Ｌ以上浓度时Ｐｃｌ值反而变大。ｐＣＭＢＳ浓度高于０．３ｍｍｏｌ／Ｌ时,细胞悬浮液在１０ｓ之前光密度下降过快,偏离理论拟合方程且不受ＤＩＤＳ抑制．半胱氨酸对ｐＣＭＢＳ引起的效应有恢复作用。结果表明ｐＣＭＢＳ和股骨架蛋白上特殊－ＳＨ基相互作用,导致ｂａｎｄ３构象改变,致使改变膜时阴离子的通透性。     

山羊关节炎─脑炎前病毒的PCR检测

山羊关节炎─脑炎前病毒的ＰＣＲ检测相文华,丁恩雨,秦运安,吕晓玲,沈荣显（中国农业科学院哈尔滨兽医研究所哈尔滨１５０００１）关键词聚合酶链反应,山羊关节炎—脑炎病毒,整合山羊关节炎—脑炎（ＣａｐｒｉｎｅＡｒｔｈｒｉｔｉｓ－Ｅｎｃｅｐｈａｌｉｔｉｓ,Ｃ...     

CBP-18, a Ca2+-Binding Protein in Rat Brain: Tissue Distribution and Localization

Abstract: The distribution of a novel calcium-binding protein with a molecular mass of 18 kDa (CBP-18) in the rat brain was studied by means of biochemical methods and immunohistochemistry on cryostat-sectioned tissue and compared with staining patterns of parvalbumin on adjacent sections. The biochemical analysis revealed high levels of CPB-18 in cortex and cerebellum, low levels in the lungs, and undetectable levels in all other tissues tested. Immunohistochemically, the polyclonal rabbit-derived antibody for CPB-18 showed selective affinity with periglomerular cells and dendrites in the olfactory bulb. Distinct immunostaining of scattered cells and their proximal dendrites was found in the anterior olfactory nuclei and in the perirhinal and entorhinal cortex. Strong staining of neuropil with recognizable but diffusely outlined cells was observed in the retrosplenial cortex, central amygdala, hippocampal rudiment, septum, area preoptica, hypothalamus, colliculus superior, and parabrachial nuclei. The cerebellum showed strong neuropil staining of both the molecular and the granule cell layer. Less intense neuropil staining and a few scattered cells were found in the neocortex, the remaining basal forebrain, and in the entire brainstem. Immunoreactivity was barely detectable or missing in the striatum, the hippocampus, the thalamus, and in the colliculus inferior. Thus, CPB-18 shows a unique staining pattern in the CNS, different from all other Ca²⁺-binding proteins studied so far.     

STRUCTURE AND DYNAMICS OF BAMBOOS IN THE WOLONG NATURAL RESERVE,CHINA

Culm (ramet) demography of two bamboos, Fargesia robusta and Bashania fangiana, was studied over 7 yr in southwest China to determine if: 1) ramet numbers remain relatively constant; 2) ramet mortality was constant; 3) density response was greater in spreading vs. compact clones; 4) extrinsic factors (e.g., predation, climate) influenced ramet dynamics; and 5) ramets that die are smaller than ones that live. Culm numbers remained relatively constant (±20%) in most plots, but culm numbers increased (>;20%) on some sites. Mortality of culms >;6 mo old over 7 yr was low and constant, but mortality of younger culms (≤6 mo) was high and variable due to predation. Spreading clones had greater recruitment response to density than compact clones, but predation and climate may have diminished or amplified the observed demographic patterns. Predators and perhaps climate influenced culm demography, and culms that died were smaller than remaining live culms. The demography of the two bamboos we studied is compared to other clonal plants, including bamboos, to identify common processes controlling ramet demography.     

脂肪酶水解植物油的研究

本文报导了薄层层析法及高压液相色谱法定性定量地测定植物油甘油酯的组成,对不同来源的脂肪酶对植物油的水解进行了研究。实验结果表明,不同来源的脂肪酶对植物油(橄榄油)的水解性不同,同一脂肪酶水解不同种类的植物油,脂肪酶的水解率也不同,脂肪酶水解植物油有最适pH和最适温度。     

Microbial nitrogen and phosphorus co-limitation across permafrost region

The status of plant and microbial nutrient limitation have profound impacts on ecosystem carbon cycle in permafrost areas, which store large amounts of carbon and experience pronounced climatic warming. Despite the long-term standing paradigm assumes that cold ecosystems primarily have nitrogen deficiency, large-scale empirical tests of microbial nutrient limitation are lacking. Here we assessed the potential microbial nutrient limitation across the Tibetan alpine permafrost region, using the combination of enzymatic and elemental stoichiometry, genes abundance and fertilization method. In contrast with the traditional view, the four independent approaches congruently detected widespread microbial nitrogen and phosphorus co-limitation in both the surface soil and deep permafrost deposits, with stronger limitation in the topsoil. Further analysis revealed that soil resources stoichiometry and microbial community composition were the two best predictors of the magnitude of microbial nutrient limitation. High ratio of available soil carbon to nutrient and low fungal/bacterial ratio corresponded to strong microbial nutrient limitation. These findings suggest that warming-induced enhancement in soil nutrient availability could stimulate microbial activity, and probably amplify soil carbon losses from permafrost areas.