Composition of cross-linked 125I-follitropin-receptor complexes

Both of the alpha and beta subunits of intact human follitropin (FSH) were radioiodinated with 125I-sodium iodide and chloramine-T and could be resolved on sodium dodecyl sulfate-polyacrylamide gels. Radioiodinated FSH was affinity-cross-linked with a cleavable (nondisulfide) homobifunctional reagent to its membrane receptor on the porcine granulosa cell surface as well as to a Triton X-100-solubilized form of the receptor. Cross-linked samples revealed three additional bands of slower electrophoretic mobility, corresponding to 65, 83, and 117 kDa, in addition to the hormone bands. The hormone alpha beta dimer band corresponded to 43 kDa. Formation of the three bands requires the 125I-hormone to bind specifically to the receptor with subsequent cross-linking. Binding was prevented by an excess of the native hormone but not by other hormones. A monofunctional analog of the cross-linking reagent failed to produce the three bands. Reagent concentration-dependent cross-linking revealed that their formation was sequential; smaller complexes formed first and then larger ones. When gels of cross-linked complexes were treated to cleave covalent cross-links and then electrophoresed in a second dimension, 18-, 22-, and 34-kDa components were released, in addition to the alpha and beta subunits of the hormone.     

Respiratory effects of naloxone

The respiratory effects of naloxone (200 micrograms X kg-1) on dogs, was studied measuring the parameters breath rate, inspiratory volume, breath minute volume, inspiratory time, total time of cycle, inspiratory volume/inspiratory time ratio, and inspiratory time/total time of cycle ratio. The statistical study was made by using the analysis of variance. Naloxone increases all the parameters studied as well as the response to CO2 while it decreases inspiratory time. The results suggest that there are opioid neurons in the respiratory centre. The blockade of the opioid receptors by naloxone almost explains the respiratory effects observed.     

Effect of naloxone on coughing

Naloxone at doses of 200 micrograms X kg-1 increases cough, in experiments carried out on dogs. With stimuli of the same intensity, after naloxone, a significant increase in the number of coughs in each fit, is observed. Changes in the first cough burst, compared with spontaneous respiration at rest, are statistically significant and they contribute to define the characteristics of the cough burst. The increase of cough by naloxone blockade of endorphinic neurons of the respiratory center shows that usually the activity of these inhibitory neurons, tonically depresses the tussive response. The antitussive opiates would seem to operate by activating these inhibitory synapses.     

接触二氧化硫后小麦叶片中逆境乙烯的生物合成

AVG和AOA强烈抑制二氧化硫处理小麦叶片中乙烯产生和ACC合成,对MACC的形成也有一定的抑制作用。CoGl_2明显抑制乙烯产生,而ACC大量积累,MACC含量则未因ACC增加而相应增加。DNP和CCCP也抑制乙烯产生,但前者引起ACC大量积累,后者引起ACC含量下降。CHI对乙烯产生和ACC形成均显示强烈的抑制作用,同时也明显抑制MACC形成。这表明小麦叶片接触SO_2引起的逆境乙烯也是循蛋氨酸→SAM→ACC→乙烯途径。     

A rapid, simple and reliable combined method for G-banding mammalian and human chromosomes

A simple and reliable method for G-banding chromosomes from human and mammalian cells is described. This rapid method combines hot saline and trypsin treatments and yields high quality G-bands in both bone marrow and cultured cells.     

Vasoactive intestinal peptide (VIP) binding to solubilized material from rat liver plasma membranes

A non-ionic detergent such as Lubrol-PX extracts in soluble form the VIP-binding structures of rat liver plasma membranes. Detergent-solubitized proteins bind specifically [¹²⁵I]VIP and the complex tracer-protein is identified by the use of Sepharose 6B columns. The interaction is only possible in the absence of detergent (below 0.001%) and is inhibited by native peptide. A molecular weight of about 80,000 was estimated for VIP-binding proteins by reference to a series of globular markers of proteins. Binding to VIP soluble proteins is specific and dependent on time as studied by the Hummel and Dreyer (Biochim. Biophys. Acta 63:530–532, 1962) assay.     

重楼属植物的免疫血清学研究

以海南重楼(Paris dunniana),花叶重楼(P.marmorata),多叶重楼(P.polyphylla),凌云重楼(P.cronquistii),五指莲(P.axialis),滇重楼(Paris polyphylla var.yunnanensis)等六种重楼属植物的根茎为材料,提取分离其球蛋白组份作为抗原,免疫家兔得到相应的抗血清。通过免疫双扩散,聚丙烯酰胺凝胶电泳、免疫电泳、免疫吸收试验以及酶标免疫等方法,研究了重楼属上述六个种和变种的血清学行为以及他们之间的相互关系。在此基础上,用不加权算术平均对群法(UPGMA)经成聚运算,得到基于平均吸收相似系数(Sabs.mean.)和Jaccard's结合系数的两种表相图,这两种表相图的结果是一致的。花叶重楼与多叶重楼有较大的血清反应相似性,五指莲与滇重楼有最大的血清反应相似性。多型种P.polyphylla在形态上的较大变异与血清反应分析的结果是一致的,而且血清反应相似性分析支持了从形态分析得出的假设:Paris dunniana在重楼属的系统发生中是一比较原始的种。