钙-钙调素与小麦苗中热激蛋白的诱导

在 34℃热激条件下 ,种子经钙预处理的小麦苗中的钙调素含量随着热激时间的延长而增加 ,热激 90min时达最大值 ,而种子用钙离子螯合剂EGTA预处理的小麦苗中钙调素含量无明显增加。种子用EGTA及钙调素拮抗剂CPZ和TFP预处理的小麦幼苗在 34℃热激时 ,热激蛋白的合成量减少。 4d的小麦幼苗在34℃或 37℃热激条件下 ,能诱导耐热性的获得 ,分别用EGTA、钙离子通道阻断剂易博定、钙调素拮抗剂TFP或CPZ预处理种子后 ,所得幼苗热诱导的耐热性的提高程度有所下降     

Role of Heat Shock Proteins in Diseases and Their Therapeutic Potential

Heat shock proteins are ubiquitously expressed intracellular proteins and act as molecular chaperones in processes like protein folding and protein trafficking between different intracellular compartments. They are induced during stress conditions like oxidative stress, nutritional deficiencies and radiation. They are released into extracellular compartment during necrosis. However, recent research findings highlights that, they are not solely present in cytoplasm, but also released into extracellular compartment during normal conditions and even in the absence of necrosis. When present in extracellular compartment, they have been shown to perform various functions like antigen presentation, intercellular signaling and induction of pro-inflammatory cytokines. Heat shock proteins represents as dominant microbial antigens during infection. The phylogenetic similarity between prokaryotic and eukaryotic heat shock proteins has led to proposition that, microbial heat shock proteins can induce self reactivity to host heat shock proteins and result in autoimmune diseases. The self-reactivity of heat shock proteins protects host against disease by controlling induction and release of pro-inflammatory cytokines. However, antibodies to self heat shock proteins haven been implicated in pathogenesis of autoimmune diseases like arthritis and atherosclerosis. Some heat shock proteins are potent inducers of innate and adaptive immunity. They activate dendritic cells and natural killer cells through toll-like receptors, CD14 and CD91. They play an important role in MHC-antigen processing and presentation. These immune effector functions of heat shock proteins are being exploited them as therapeutic agents as well as therapeutic targets for various infectious diseases and cancers.     

Heat Shock Proteins and Circadian Rhythms

Significant circadian rhythms in heat shock gene expression were observed in a prokaryotic species (Synechocystis). In eukaryotes, in contrast, several heat shock genes (constitutive and inducible) were shown to be constantly expressed. A few cases of circadian expression of heat shock proteins (HSPs), however, have been reported. Significant circadian changes of thermotolerance were observed in yeast and several plant species. Higher thermo-tolerance can be attributed to a higher abundance of HSPs, but also to other adaptive mechanisms. Zeitgeber effects of temperature changes can be explained on the basis of their direct effects on the state variables of the clock gene (per, frq) expression and its negative feedback loop. Effects of increased HSP concentrations, as observed after heat shock, but also after light and serotonin (5HT), appear possible, in particular with respect to nuclear localization of the clock (PER) protein, but these effects have not been documented yet. Thus, the role of HSPs in the circadian clock system is little understood and, from our point of view, deserves more attention. (Chronobiology International, 13(4), 239-250, 1996)     

叶绿体小分子量热激蛋白介绍

本文对叶绿体小分子量热激蛋白的研究进行了简要的回顾和总结。叶绿体小分子量热激蛋白是热激蛋白超家族的成员,具有3个特殊的保守区域;当植物遇到热胁迫时,叶绿体小分子量热激蛋白能够保护光合系统Ⅱ和类囊体膜;初步分析了叶绿体小分子量热激蛋白与植物的耐热性和耐冷性关系以及其分子伴侣功能。     

叶绿体小分子量热激蛋白介绍

本文对叶绿体小分子量热激蛋白的研究进行了简要的回顾和总结.叶绿体小分子量热激蛋白是热激蛋白超家族的成员,具有3个特殊的保守区域;当植物遇到热胁迫时,叶绿体小分子量热激蛋白能够保护光合系统Ⅱ和类囊体膜;初步分析了叶绿体小分子量热激蛋白与植物的耐热性和耐冷性关系以及其分子伴侣功能.     

Vertebral Abnormalities Following Heat Shock in Xenopus Embryos

Xenopus embryos were heat-shocked at several stages of development and vertebral abnormalities were examined by means of in situ staining. A high incidence of vertebral abnormalities was evident in larvae treated at the neurula stages (stages 15 and 20) and at the tailbud stages (stages 32 and 35). Heat shock at the neurula stages led to malformed vertebrae and their fusion following an altered arrangement of the arcualia. Heat shock at the tailbud stages induced an asymmetric arrangement of the sacrum and a change in the number of vertebrae, but the arrangement of the arcualia was not affected. Early events of the development of the vertebral column are discussed in relation to somitogenesis.     

猪胚胎热应激后耐低温性的变化

手术或屠宰采取措囊胚（Ｂ）、扩张囊胚（ＥＢ）。孵出囊胚（ＨＢ）,置于含１０％ＦＣＳ的ＧＩＴ液中进行４２℃水浴１０分钟的热应激和－７℃酒精糟１０分钟的低温感受试验。结果,热应激对猪胚的存活率及发育率均无影响（Ｐ＞０．０５）;而热应激提高了猪胚对低温的耐受程度,热应激的胚胎再经低温感受试验后,培养２４小时的ＥＢ（φ＜５０）、ＥＢ（φ≥５０）和ＨＢ的活细胞数分别较相应的对照组提高３５．５％、４１．３％和５１．１％,差异显著（Ｐ＜０．０５）,但在热应激处理液中添加了蛋白合成抑制剂者没有产生这一效果,此结果证明,热应激很可能诱发猪胚内产生抗低温的应激蛋白质,这为进一步研究猪胚胎冷冻和改进猪胚冷冻前处理提供了依据和可能途径。     

Presence of Heat Shock mRNAs in Field Crown Soybeans

Our laboratory has extensively defined many parameters of the heat shock (HS) response in etiolated soybean (Glycine max [L.] Merr.) hypocotyls, including the identification of cDNA clones for mRNAs encoding several low molecular weight HS proteins. We have now investigated the response of mature plants to a HS in a growth chamber and to high temperature stress under field conditions. Soybean plants show induction of HS mRNAs when the temperature of the chamber is rapidly shifted from 28°C to 45°C. This temperature of induction is significantly higher than the optimal induction temperature for etiolated hypocotyls, probably reflecting the ability of mature plants to lower their leaf temperatures below the ambient air temperature through transpirational cooling. Samples of soybean leaves were taken from an irrigated and a nonirrigated field during a 24-h period when midday temperatures reached 40°C. Several HS mRNAs were present in samples from both fields, although the levels of these mRNAs were much higher in nonirrigated leaves. This differential response of HS mRNA steady state levels was not a response to water stress, since water-stressed plants at 28°C did not induce HS mRNAS. Rather, these quantitative differences are probably due to differences in actual leaf temperatures between irrigated and nonirrigated leaves. The presence of these HS mRNAS in field-grown plants suggests that HS proteins are produced as part of the normal plant response to high temperature.     

植物小分子热休克蛋白

在热刺激下,真核和原核细胞都能产生一类小分子热休克蛋白(smallheatshockproteins,sHSPs),植物sHSPs数量、种类众多而且十分重要。目前已经发现植物中至少存在6种细胞内sHSPs。植物在特定的发育阶段或受到逆境条件的刺激产生sHSPs。大量研究表明sHSPs通过分子伴侣机制保护逆境中的细胞,在植物逆境忍耐中起着重要作用。     

热激蛋白70的研究进展

热激蛋白(HSP70)作为分子伴侣参与细胞内许多重要反应,从而对生物体起着重要的作用。随着研究的深入,其生物学功能不断被发现和利用的同时,HSP70的应用前景也变得越来越广泛。已有研究者对HSP70的生物学功能做了详细介绍,我们主要对近年来HSP70在医学及环境监测等方面的应用进行综述。     

Analysis and Phylogeny of Small Heat Shock Proteins from Marine Viruses and Their Cyanobacteria Host

Small heat shock proteins (sHSPs) are oligomeric stress proteins characterized by an α-crystallin domain (ACD) surrounded by a N-terminal arm and C-terminal extension. Publications on sHSPs have reported that they exist in prokaryotes and eukaryotes but, to our knowledge, not in viruses. Here we show that sHSPs are present in some cyanophages that infect the marine unicellular cyanobacteria, Synechococcus and Prochlorococcus. These phage sHSPs contain a conserved ACD flanked by a relatively conserved N-terminal arm and a short C-terminal extension with or without the conserved C-terminal anchoring module (CAM) L-X-I/V, suggested to be implicated in the oligomerization. In addition, cyanophage sHSPs have the signature pattern, P-P-[YF]-N-[ILV]-[IV]-x(9)-[EQ], in the predicted β2 and β3 strands of the ACD. Phylogenetically, cyanophage sHSPs form a monophyletic clade closer to bacterial class A sHSPs than to cyanobacterial sHSPs. Furthermore, three sHSPs from their cellular host, Synechococcus, are phylogenetically close to plants sHSPs. Implications of evolutionary relationships between the sHSPs of cyanophages, bacterial class A, cyanobacteria, and plants are discussed.     

Germination-induced Changes in Chromosomal Proteins of Spring and Winter Wheat Embryos

The template activity of chromatin from winter wheat embryos gradually increased during germination and was regulated with some nonhistone proteins different from the two major ones, molecular weight 39k and 59k polypeptides, previously reported.     

小热休克蛋白的结构和功能

小热休克蛋白（small heat shock protein,sHSP）几乎存在于所有生物体中,其主要结构是一个保守的α晶体蛋白(α-crystallin)结构域,由约90个氨基酸残基组成,与其相邻的是可变的N端域. N端域能够调节低聚体形成、亚单位动力学及其与底物的结合.sHSP能够与细胞内各组分（蛋白质、细胞核、细胞骨架元件、膜）进行相互作用,以维持细胞的稳定.小热休克蛋白家族成员的共同特点是特殊丝氨酸残基上的磷酸化,磷酸化作用对于受到胁迫时的细胞非常重要.由MAPKAP激酶 2/3和p38参与的级联反应能够诱导sHSP发生磷酸化,从而调节sHSP的低聚体状态,而低聚体状态和sHSP的生物学功能密切相关.本文介绍sHSP的结构特征和细胞内的作用底物,并讨论sHSP被不同的蛋白激酶磷酸化及磷酸化作用对低聚体状态和伴侣活性的影响.     

Heat Shock Proteins of Cyanobacterium Anacystis nidulans

Cells of Anacystis nidulans grown at 30°C were incubatedwith ¹⁴C-Chlorella protein hydrolysate at the elevated temperatures(30–55°C) and the effect of heat shock treatment onprotein synthesis was studied. Incubation temperatures higherthan 45°C caused a significant decrease in the incorporationof amino acids into proteins. Further, the heat shock treatmentinduced significant changes in the fluorographic profile ofthe newly synthesized proteins. (Received October 25, 1985; Accepted December 4, 1985)     

极端嗜热古菌的热休克蛋白

随着生物工程产业对于耐高温酶和菌体的需求, 极端嗜热古菌热休克蛋白(heat shock proteins, HSPs)的研究更受重视, 其热休克蛋白体系非常简洁, 不含HSP100s和HSP90s, 就是HSP70(DnaK)、HSP40、(DnaJ)和GrpE等嗜温古菌可能含有的在极端嗜热古菌中几乎不含有, 即仅包括HSP60, sHSP, prefoldin和AAA+蛋白四大类, 因此对其结构、功能和作用机制的研究在理论和实践上都特别有意义。系统地介绍了这四大类组分的结构、功能和作用机制和协同作用的研究进展, 论述了极端嗜热古菌热休克蛋白的系列研究难点和困惑, 展望了进一步的研究方向和重点。