工业发酵废液生产单细胞蛋白的研究

从工业发酵生产柠檬酸，土霉素无毒有机废水中分别筛选出合适的酵母菌株Ｌｃ１，９，１１，Ｋｙ１１，利用这种无毒有机废水发酵生产单细胞蛋白，其中Ｋｙ１１产率可达１．１１％，粗蛋白含量可达４６．５％，不仅可获得单细胞蛋白，而且改善了此类废水的水质。     

非同源球蛋白三级结构预测

研究了主链二面角的统计分布，在Ｒａｍａｃｈａｎｄｒａｎ图上将二面角（　，ψ）分成６个区域．对于每一残基，考虑其前后残基的影响后，给出在这些区域中出现的相对几率．根据Ｂｏｌｔｚｍａｎｎ原理，由几率导出能量．再考虑非局域的蛋白质整体性质（结构含量、疏水作用等）对系统能量的贡献，由能量极小化定出结构．对（　，ψ）的预测成功率为５３．４％．若由结构含量实测值出发，可使预测成功率达５７．３％．亲疏水氨基酸在球蛋白中分布的符合率为５１％．讨论了由（　，ψ）分区值导出整体结构的问题．     

2种无银保鲜剂对切花菊的保鲜效应

研究保鲜剂（２％蔗糖＋５０ｍｇ／Ｌ柠檬酸＋１００ｍｇ／Ｌ８－羟基喹啉＋１ｍｇ／Ｌ６－ＢＡ）和保鲜剂２号（２％蔗糖＋５０ｍｇ／Ｌ水杨酸＋１００ｍｇ／Ｌ８－羟基喹啉＋１ｍｇ／Ｌ６－ＢＡ）对“黄秀凤”切花菊（Ｃｈｒｙｓａｎｔｈｅｍｕｍｍｏｒｉｆｏｌｉｕｍｃｖ．“ＨｕａｎｇＸｉｕｆｅｎｇ”）瓶插寿命和瓶插期间花枝的水分状况,叶绿素和可溶性蛋白质含量以及过氧化物酶（ＰＯＤ）活性等生理延长２ｄ但与延长花冠寿命     

Leptin, but not a β3-adrenergic agonist, upregulates muscle uncoupling protein-3 messenger RNA expression: short-term thermogenic interactions

The short-term effects of leptin and a β₃-adrenoceptor agonist on thermogenesis and expression of uncoupling proteins (UCPs) in brown adipose tissue (BAT) and muscle and their possible interactions were assessed. One hour after administration of the β₃-adrenoceptor agonist Trecadrine, a statistically significant increase in UCP1 messenger RNA (mRNA) expression in BAT was observed, whereas UCP2 and UCP3 in both BAT and gastrocnemius muscle were unaffected. Leptin induced an upregulation of UCP3 mRNA in muscle, with no changes in BAT UCP1 mRNA. A statistical interaction was found between leptin and Trecadrine in rectal temperature. The present study provides evidence, for the first time, of the induction of UCP3 mRNA expression in skeletal muscle by leptin in nongenetically obese animals. Received 5 March 1999; received after revision 19 April 1999; accepted 21 April 1999     

Production of functional rat liver PSP protein in Escherichia coli

An efficient Escherichia coli expression system for the production of a perchloric acid-soluble protein (PSP) has been constructed. Complementary DNA encoding PSP was inserted into an inducible bacterial expression vector pGEX-4T-1. After the plasmid introduced into E. coli was expressed by isopropyl 1-thio-β-D-galactopyranoside (IPTG), the recombinant product was purified by glutathione-Sepharose 4B affinity chromatography. The purified product showed the expected NH₂-terminal sequence, but the translation inhibitory activity of this product was 10 times lower compared with that of authentic PSP isolated from rat liver. Received 8 October 1998; received after revision 6 November 1998; accepted 6 November 1998     

Insulin activates Gαil,2 protein in rat hepatoma (HTC) cell membranes

Insulin action is initiated by binding to its cognate receptor, which then triggers multiple cellular responses by activating different signaling pathways. There is evidence that insulin receptor signaling may involve G protein activation in different target cells. We have studied the activation of G proteins in rat hepatoma (HTC) cells. We found that insulin stimulated binding of guanosine 5′-O-(3-thiotriphosphate) (GTP-γ-³⁵S) to plasma membrane proteins of HTC cells, in a dose-dependent manner. This effect was completely blocked by pertussis toxin treatment of the membranes, suggesting the involvement of G proteins of the Gα _i/Gα _o family. The expression of these Gα proteins was checked by Western blotting. Next, we used blocking antibodies to sort out the specific Gα protein activated by insulin stimulation. Anti-Gα _il,2 antibodies completely prevented insulin-stimulated GTP binding, whereas anti-Gα _o,i3 did not modify this effect of insulin on GTP binding. Moreover, we found physical association of the insulin receptor with Gα _i1,2 by copurification studies. These results further support the involvement of a pertussis toxin-sensitive G protein in insulin receptor signaling and provides some evidence of specific association and activation of Gα _i1,2 protein by insulin. These findings suggest that Gα _i1,2 proteins might be involved in insulin action. Received 23 September 1998; received after revision 23 November 1998; accepted 25 November 1998     

蛋白质折迭的若干物理问题

综述了蛋白质折送的基本实验特征，讨论了亘子构象动力学的有关理论结果，分析了格子模拟得到的启示，在此基础上对Ａｎｆｉｎｓｅｎ的热力学假设提出质疑，提出鲁棒极小值的概念，研究了序列决定构象问题，并对折迭途径中的一些问题进行了初步探讨。     

Juvenile hormone catabolism inManduca sexta: Homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product

We studied time-dependent metabolism of (10R)-[³H] juvenile hormone (JH) III and (10R, 11S)-[³H]JH I injected intoManduca sexta larvae; the hormones are metabolized to polar metabolites, expecially the JH acid-diol, and an unknown. Products were analyzed using a reversed-phase liquid chromatography assay. (10R)-JH III is metabolized much more rapidly than (10R, 11S)-[³H]JH I, whether injected seperately or as a mixture of hormones. The unknown metabolites of JH I and JH III were identified as phosphate conjugates of JH I and JH III diol by tandem mass spectral analysis of isolated samples. The phosphate conjugate of JH I diol is the principle end product of JH I metabolism.     

无乙肝症状的“健康人群”中前S_2蛋白及抗前S_2的血清学调查

采用国产单克隆抗体酶标试剂盒(McAb—ELISA)对广东某地区无乙肝症状的298人作了血清前S_2蛋白及抗前S_2检测,同时检测各项乙型肝炎病毒血清学标志(HBVM)及肝功能。全部检测对象肝功能正常。前S_2阳性率7.72％。抗前S_2阳性率5.70％。前者与HBsAg及其它乙肝病毒复制标志(HBcAg、PHSA-R、HBcAg、抗-HBcIgM及HBVDNA)有平行关系,后者则与抗HBs有平行关系。结果提示前S_2可作为一项敏感的HBV复制及传染性的指标,抗前S_2是一项乙肝感染的恢复标志,二者有重要的流行病学与临床意义,检测证实人群中存在相当数量的HBV携带者和隐性感染者。     

蛋白质在逆胶束中增溶的分子热力学模型

为建立文题所述模型,以微乳液的稳定性理论为基础,综合分析了表面活性剂分子在油-水界面上的缔合作用、界面膜弯曲时产生的附加能量、各种类型的混合熵以及表面活性剂分子和蛋白质分子的静电作用。所得模型正确地反映了含蛋白质的逆胶束系统稳定的原因,较好地描述了蛋白质转移后胶束大小的变化以及蛋白质转移率随电解质浓度变化的特殊的实验规律。