Insulin treatment of prepubertal children with insulin-dependent diabetes imp roves body protein balance by decreasing the rate of protein degradation without stimulating protein synthesis. However, insulin also cause...Insulin treatment of prepubertal children with insulin-dependent diabetes imp roves body protein balance by decreasing the rate of protein degradation without stimulating protein synthesis. However, insulin also causes hypoaminoacidemia, so the inability of insulin to stimulate protein synthesis may have been limited by substrate availability. We investigated the ability of insulin to stimulate protein synthesis in growing pubertal children who were given sufficient amino a cids to counter insulin-induced hypoaminoacidemia. Protein metabolism in six pu bertal children with type 1 diabetes was assessed from leucine kinetics during a primed, 6-h infusion of L-[1-13C] leucine. The children were studied in the postabsorptive state during a basal (insulin withdrawn) period and during the in fusion of 0.83 mU ·kg -1 ·min-1 human regular insulin. Amino acids and gluco se were given with insulin to prevent hypoaminoacidemia and hypoglycemia. Net le ucine balance was significantly higher with insulin than in the basal state, the result of decreased protein degradation but also decreased protein synthesis. T he data suggest that insulin alone does not increase protein synthesis in pubert al children with type 1 diabetes.展开更多
2009年度诺贝尔化学奖授予了美国科学家Venkatraman Ramakrishnan、Thomas A. Steitz和以色列科学家Ada E. Yonath,以表彰他们"对核糖体结构和功能的研究"。高分辨率的核糖体晶体结构使得人们能够在原子水平深入精确地理解核...2009年度诺贝尔化学奖授予了美国科学家Venkatraman Ramakrishnan、Thomas A. Steitz和以色列科学家Ada E. Yonath,以表彰他们"对核糖体结构和功能的研究"。高分辨率的核糖体晶体结构使得人们能够在原子水平深入精确地理解核糖体的分子机制,并且为基于结构的合理化抗生素设计打下了坚实基础。以色列女科学家Ada E. Yonath是整个核糖体晶体结构研究领域的核心人物,她10多年坚持不懈地进行多种细菌核糖体的提纯与晶体生长工作,才使得核糖体高分辨率晶体结构解析成为可能。本文对2009年度诺贝尔化学奖的研究工作进行简要介绍。展开更多
A cDNA Library was constructed with the heat shocked tomato ( Lycopersicon esculentum Mill.) flowers and then was screened with the probes of mitochondrial and endoplasmic reticulum conservative regions that were clon...A cDNA Library was constructed with the heat shocked tomato ( Lycopersicon esculentum Mill.) flowers and then was screened with the probes of mitochondrial and endoplasmic reticulum conservative regions that were cloned by using RT-PCR. The complete cDNAs of mitochondrial and endoplasmic reticulum small heat shock protein ( shsp) were selected out from the cDNA library. Furthermore, the temperature responses of these shsp genes were determined. Northern hybridization showed that the heat response temperatures of both genes in tomato flower were lower than that in leaf and that mitochondria shsp in leaf was cold-inducible. In this paper, the molecular features of the cloned genes, the causes of the uncommon heat response temperatures of sHSP in newer and the cold inducible character of mitochondria shsp gene in leaf were discussed.展开更多
文摘Insulin treatment of prepubertal children with insulin-dependent diabetes imp roves body protein balance by decreasing the rate of protein degradation without stimulating protein synthesis. However, insulin also causes hypoaminoacidemia, so the inability of insulin to stimulate protein synthesis may have been limited by substrate availability. We investigated the ability of insulin to stimulate protein synthesis in growing pubertal children who were given sufficient amino a cids to counter insulin-induced hypoaminoacidemia. Protein metabolism in six pu bertal children with type 1 diabetes was assessed from leucine kinetics during a primed, 6-h infusion of L-[1-13C] leucine. The children were studied in the postabsorptive state during a basal (insulin withdrawn) period and during the in fusion of 0.83 mU ·kg -1 ·min-1 human regular insulin. Amino acids and gluco se were given with insulin to prevent hypoaminoacidemia and hypoglycemia. Net le ucine balance was significantly higher with insulin than in the basal state, the result of decreased protein degradation but also decreased protein synthesis. T he data suggest that insulin alone does not increase protein synthesis in pubert al children with type 1 diabetes.
文摘2009年度诺贝尔化学奖授予了美国科学家Venkatraman Ramakrishnan、Thomas A. Steitz和以色列科学家Ada E. Yonath,以表彰他们"对核糖体结构和功能的研究"。高分辨率的核糖体晶体结构使得人们能够在原子水平深入精确地理解核糖体的分子机制,并且为基于结构的合理化抗生素设计打下了坚实基础。以色列女科学家Ada E. Yonath是整个核糖体晶体结构研究领域的核心人物,她10多年坚持不懈地进行多种细菌核糖体的提纯与晶体生长工作,才使得核糖体高分辨率晶体结构解析成为可能。本文对2009年度诺贝尔化学奖的研究工作进行简要介绍。
文摘A cDNA Library was constructed with the heat shocked tomato ( Lycopersicon esculentum Mill.) flowers and then was screened with the probes of mitochondrial and endoplasmic reticulum conservative regions that were cloned by using RT-PCR. The complete cDNAs of mitochondrial and endoplasmic reticulum small heat shock protein ( shsp) were selected out from the cDNA library. Furthermore, the temperature responses of these shsp genes were determined. Northern hybridization showed that the heat response temperatures of both genes in tomato flower were lower than that in leaf and that mitochondria shsp in leaf was cold-inducible. In this paper, the molecular features of the cloned genes, the causes of the uncommon heat response temperatures of sHSP in newer and the cold inducible character of mitochondria shsp gene in leaf were discussed.
