Phenytoin-induced DNA synthesis and inositol 1,4,5-triphosphate formation in L-929 fibroblasts

Summary Culture of L-929 fibroblasts in the presence of phenytoin (2.5–5.0 g/ml) increased DNA synthesis, as indicated by increased [³H]thymidine uptake, while a higher dose (20 g/ml) inhibited DNA synthesis. In like manner, a low dose of phenytoin (5.0 g/ml) was effective in increasing inositol 1,4,5-trisphosphate formation while a higher dose (10 g/ml) tended to inhibit this activity. These data suggest that the formation of inositol phosphate second messengers may play a role in phenytoin-induced fibroblast proliferation and connective tissue growth.     

肌醇对玉米幼苗抗寒性的影响

用４０ｍｍｏｌ／Ｌ肌醇浸种处理玉米种子,可以提高术米幼苗的抗寒性。胝温胁迫后,处理组的超氧物歧化酶、过氧化物酶、抗坏血酸过氧化物酶、过氧化氢酶的活性比对照组下降的幅度小;恢复生长后,处理组４种酶活性的提高幅度比对照组大。     

Transduction of the chemotactic cAMP signal across the plasma membrane ofDictyostelium cells

AggregatingDictyostelium cells secrete cAMP during cell aggregation. cAMP induces two fast responses, the production of more cAMP (relay) and directed cell locomotion (chemotaxis). Extracellular cAMP binds to G-protein-coupled receptors leading to the activation of second messenger pathways, including the activation of adenylyl cyclase, guanylyl cyclase, phospholipase C and the opening of plasma membrane Ca²⁺ channels. Many genes encoding these sensory transduction proteins have been cloned and null mutants of nearly all components have been characterized in detail. Undoubtedly, activation of adenylyl cyclase is the most complex, involving G-proteins, a soluble protein called CRAC and components of the MAP kinase pathway. Null mutants in this pathway do not aggregate, but can exhibit chemotaxis and develop normally when supplied with exogenous cAMP. The pathways leading to the activation of phospholipase C were identified, but unexpectedly, deletion of the phospholipase C gene has no effect on chemotaxis and development, nor on intracellular Ins(1,4,5)P₃ levels; the metabolism of this second messenger will be discussed in some detail. Activation of guanylyl cyclase is G-protein-dependent and essential for chemotaxis. Analysis of a collection of chemotactic mutants reveals that most mutants are defective in either the production or intracellular detection of cGMP, thereby placing this second messenger at the center of chemotactic signal transduction. Analysis of the cAMP-mediated opening of plasma membrane calcium channels in signal transduction mutants suggests that it has two components, one that depends on G-proteins and intracellular cGMP and one that is G-protein-independent.     

降低菲丁中蛋白质含量的工艺条件研究

文章研究了菲丁中蛋白质含量降低的方法及工艺条件。实验结果表明 ,采用适宜的工艺条件 ,可使菲丁中蛋白质的含量下降58 %以上     

提高肌醇收率的工艺方法研究

为提高肌醇收率，粗菲汀经酸溶，过滤，碱中和沉淀而精制，用离子交换法对肌醇水溶液进行精制。可提高肌醇的收率(72．17％～91．10％)，与中和沉淀法相比，具有工艺流程短，操作简单，产品收率高等优点。     

Effects of pertussis toxin onα 1-agonist-mediated phosphatidylinositide turnover and myocardial cell hypertrophy in neonatal rat ventricular myocytes

Summary In neonatal rat ventricular myocytes pretreatment with pertussis toxin did not affect 1 M (–)-norepinephrine stimulation of inositol phosphates or myocardial cell hypertrophy as measured either by protein radiolabelling or by myocardial cell protein content. Thus guanine nucleotide protein (s) ADP-ribosylated by pertussis toxin do not play a role in two ₁-adrenoceptor-mediated processes, phosphatidylinositide turnover and induction of myocardial cell hypertrophy.     

激素类物质对大白桩菇菌丝生长的影响

研究了激素类物质三十烷醇、肌醇、赤霉素对大白桩菇菌丝生长的影响.结果表明,三十烷醇对大白桩菇菌丝生长具有更大的促进作用,最适宜的添加质量浓度为1 mg/L.     

肌醇和水弱相互作用的理论研究

采用DFT方法,在6-31G,6-31G（d）,6-31＋G（d）,6-31＋＋G（d,p）基组水平上,对肌醇与水分子之间的相互作用进行了研究,找到7种稳定结构：一种单氢键结构、五种双氢键结构和一种三氢键结构．在此基础上计算了络合物在不同基组水平上的相互作用能,并对其进行了基集超位误差（BSSE）校正和零点振动能（ZPVE）校正．此外,采用Onsager溶液反应场模型,在6-31＋G（d）基组水平上,对络合物的构型及相互作用能进行研究,发现溶剂化使络合物的结构及相互作用能发生了改变．