Conformational Studies of Tachykinin Peptides Using NMR Spectroscopy

A conformational analysis in water and DMSO of two tachykinin family peptides (scyliorhinin I (ScyI) and scyliorhinin II (ScyII)) was carried out by 1D and 2D NMR (DQF-COSY, TOCSY, HMQC, HMBC, NOESY and ROESY) and molecular dynamics calculation methods. In DMSO, two groups of conformations (major and minor) were obtained for both peptides based on the experimental data. The conformations proposed for ScyI represent a folded structure, which shows certain similarities to the structures reported for other NK-1 and NK-2 tachykinin agonists. In water ScyII displays a flexible, extended structure, whereas in DMSO the structure is more compact and, in the fragment from the centre to the C-terminus, several -turns may be present.     

Conformational Studies of Tachykinin Peptides Using NMR Spectroscopy

Summary A conformational analysis in water and DMSO of two tachykinin family peptides (scyliorhinin I (ScyI) and scyliorhinin II (ScyII)) was carried out by 1D and 2D NMR (DQF-COSY, TOCSY, HMQC, HMBC, NOESY and ROESY) and molecular dynamics calculation methods. In DMSO, two groups of conformations (major and minor) were obtained for both peptides based on the experimental data. The conformations proposed for ScyI represent a folded structure, which shows certain similarities to the structures reported for other NK-1 and NK-2 tachykinin agonists. In water ScyII displays a flexible, extended structure, whereas in DMSO the structure is more compact and, in the fragment from the centre to the C-terminus, several β-turns may be present.     

Porin activity of the native and recombinant outer membrane protein Oms28 of Borrelia burgdorferi.

The outer membrane-spanning (Oms) proteins of Borrelia burgdorferi have been visualized by freeze-fracture analysis but, until recently, not further characterized. We developed a method for the isolation of B. burgdorferi outer membrane vesicles and described porin activities with single-channel conductances of 0.6 and 12.6 nS in 1 M KCI. By using both nondenaturing isoelectric focusing gel electrophoresis and fast-performance liquid chromatography separation after detergent solubilization, we found that the 0.6-nS porin activity resided in a 28-kDa protein, designated Oms28. The oms28 gene was cloned, and its nucleotide sequence was determined. The deduced amino acid sequence of Oms28 predicted a 257-amino-acid precursor protein with a putative 24-amino-acid leader peptidase I signal sequence. Processed Oms28 yielded a mature protein with a predicted molecular mass of 25,363 Da. When overproduced in Escherichia coli, the Oms28 porin fractionated in part to the outer membrane. Sodium dodecyl sulfate-polyacrylamide gel-purified recombinant Oms28 from E. coli retained functional activity as demonstrated by an average single-channel conductance of 1.1 nS in the planar lipid bilayer assay. These findings confirmed that Oms28 is a B. burgdorferi porin, the first to be described. As such, it is potential relevance to the pathogenesis of Lyme borreliosis and to the physiology of the spirochete.     

菽麻（Crotalaria juncea L.）抗肿瘤化学成份的研究

我们从菽麻(Crotalaria juncea L.)种子中提取、分离出菽麻生物碱Ⅰ,对多种动物瘤谱具有较明显的抑制作用。并且对生物碱Ⅰ进行了熔点、旋光、红外光谱、核磁共振谱、质谱等理化测定,均与Trichodesmine性状一致。     

以人精子抗原消化道免疫后的体液免疫反应

The inbred Balb/c and C57 mice, and the outbred Swiss Webster mice were intragastrointestinally immunized with human sperm antigens. The lymphocytes from the spleen, mesenteric lymph node (MLN), Peyer's patch (PP) and uterus or epididymis were isolated and cultured. The lymphocyte-secreting antisperm IgG and IgA and the antisperm antibodies in the gut wash and serum were determined with enzyme-linked immunosorbent assay (ELISA). In the Balb/c and Swiss Webster mice, the immune responses to sperm have shown to be stronger than that in C57, stronger in female than in male. The antigenicity of sperm membrane extracts seems to be higher than that of whole sperm. Antisperm antibodies secreted by lymphocytes from the epididymis and uterus have demonstrated to be detectable. For stimulation of the local immune response, the intra-PP and intralumina immunizations are more effective than others.     

UPPER TRIASSIC SPORO-POLLEN ASSEMBLAGES FROM MOSUOHE RIVER VALLEY OF BAODING, SICHUAN

In 1972, after frequent investigations on lithology, sedimentology and palaeontology (especially on palaeobotany), the Upper Triassic coal series (formerly the "Lalaqing Coal Series") in the Baoding area, southwestern Sichuan was previously divided by No. 1 Regional Geological Survey Team of Yunnan Province into two formations in ascending order as the Daqiaodi Formation, and the Daqing Formation (consisting of the Lower and Upper Members).     

野生棉与栽培棉种间杂交胚珠离体培养的胚胎发育研究

以陆地棉(Gossypium hirsutum L.)做母本,野生的瑟伯氏棉(Gossypium thurberi Tod)和克劳茨基棉(Gossypium klotzschianum Anderss.)做父本,并以陆地棉自交为对照,取杂交授粉后两天的胚珠进行离体培养,研究胚胎发育。在培养条件下,三种遗传型合子启动的时间不一致,而且胚乳的发育也存在差异。珠心和胚囊腔的生长变化在有胚胚珠和无胚胚珠之间,存在明显的不同。球形胚时期,是杂种胚能否正常发育的关键时期。离体培养,改变了自然杂种状态的胚和胚乳以及胚和母体组织的不协调关系,因此产生了较多的杂种胚。     

酯酶同功酶在分析亚洲玉米螟抗药性中的应用

以聚丙烯酰胺凝胶电泳法对室内选育的亚洲玉米螟(Ostrinia furnacalis(Guenèe))抗杀灭菊酯和抗呋喃丹品系的酯酶同功酶进行分析,并与感性品系比较,差异十分明显,为鉴别害虫抗药性的遗传变异提供了有价值的依据,并从方法学的几个侧面进行探讨,为广泛研究害虫抗药性机理做一些基础工作。     

Light inhibition of the conversion of 1-aminocyclopropane-1-carboxylic acid to ethylene in leaves is mediated through carbon dioxide

The mechanism of light-inhibited ethylene production in excised rice (Oryza sativa L.) and tobacco (Nicotiana tabacum L.) leaves was examined. In segments of rice leaves light substantially inhibited the endogenous ethylene production, but when CO₂ was added into the incubation flask, the rate of endogenous ethylene production in the light increased markedly, to a level which was even higher than that produced in the dark. Carbon dioxide, however, had no appreciable effect of leaf segments incubated in the dark. The endogenous level of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, was not significantly affected by lightdark or CO₂ treatment, indicating that dark treatment or CO₂exerted its effect by promoting the conversion of ACC to ethylene. This conclusion was supported by the observations that the rate of conversion of exogenously applied ACC to ethylene was similarly inhibited by light, and this inhibition was relieved in the presence of CO₂. Similar results were obtained with tobacco leaf discs. The concentrations of CO₂ giving half-maximal activity was about 0.06%, which was only slightly above the ambient level of 0.03%. The modulation of ACC conversion to ethylene by CO₂ or light in detached leaves of both rice and tobacco was rapid and fully reversible, indicating that CO₂ regulates the activity, but not the synthesis, of the enzyme converting ACC to ethylene. Our results indicate that light inhibition of ethylene production in detached leaves is mediated through the internal level of CO₂, which directly modulates the activity of the enzyme converting ACC to ethylene.Abbreviation ACC 1-aminocyclopropane-1-carboxylic acid Recipient of a Republic of China National Science Council Fellowship