浅谈高等动物常见的几种应激现象

浅谈高等动物常见的几种应激现象宗效明（河北省阳原县第一中学０７５８００）张艳平（河北省容城小里中学０７１７００）生物体都具有应激性。如植物根的向地生长,茎则背地生长,这是植物对重力发生的应激反应;昆虫中的蝶类白天活动,蛾类夜晚活动,这是昆虫对日光发生...     

植物的应激反应和应激蛋白

植物的应激反应和应激蛋白王三根（西南农业大学植物生理生化教研室,重庆６３０７１６）关键词应激反应,应激蛋白,热休克蛋白自从１９６２年Ｒｉｔｏｓｓａ发现果蝇在热击下引起唾液腺染色体发生蓬松现象,并有转录活性以来,关于热休克蛋白（Ｈｅａｔｓｈｏｃｋｐｒｏ...     

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。     

海洋微藻对重金属镉胁迫的抗氧化应激适应性

近海海域重金属镉污染已成为全球性的环境灾难。镉对有机体的氧化应激胁迫是引发有机体毒害效应的关键原因。海洋微藻是海域生态系统中初级生产者,研究其抵抗镉氧化应激毒害的过程和机理对海洋生态学具有重要科学意义。海洋微藻在长期进化发展过程中,形成了耐受重金属镉毒害的生长适应性反应,抵抗镉氧化应激胁迫是海洋微藻减轻或消除镉毒害的关键所在。文章概述当前近海重金属镉的污染现状,归纳重金属镉对海洋微藻的氧化应激毒害效应,提出海洋微藻对镉胁迫的抗氧化应激适应性,简介几种典型的抗氧化应激酶类与非酶类物质,最后指出该领域的关键问题并进行展望。     

镉对植物的生理生态效应的研究进展

综述了镉（Ｃｄ）在植物中的积累、分布、形态和植物对镉毒害的反应及影响镉毒性因素的研究进展,并指出存在的问题和发展前景。     

慢性应激对大鼠海马锥体细胞形态结构的效应

为研究慢性应激相关精神障碍的发病机制,采用尼氏（Nissl）染色法、高尔基（Golgi）镀染法和透射电镜技术,探讨慢性应激对大鼠海马CA1、CA3区锥体细胞形态结构的效应.结果显示应激组大鼠海马CA1区锥体细胞形态结构较对照组无明显变化.应激组海马CA3区锥体细胞数（35.14±3.85）较对照组(38.74±3.54)显著减少（P＜0.05）;顶树突的总长度（155.67 μm±33.32 μm）较对照组（195.63 μm±34.61 μm）显著缩短（P＜0.05）;应激组大鼠海马CA3区锥体细胞出现超微结构的改变,包括细胞固缩、体积缩小、核膜皱缩、线粒体变性和粗面内质网模糊不清.这提示海马CA3区锥体细胞形态结构的改变,可能是慢性应激相关精神障碍的病理生理基础.     

大鼠冷束缚应激时胃粘膜损伤与外周β—内啡肽关系的实验研究

目的：探讨冷束缚应激大鼠血浆及胃黏膜中β－内啡肽（β－endorphine)的变化及作用。方法：制作大鼠冷束缚应激模型,以放免法测定应激0,1／4,2,8h血浆及胃黏膜中β－内啡肽的含量,同时测定胃液pH,胃黏膜溃疡指数（UI）,另设两预处理组,分别于应激前15分钟用纳洛酮（1．6mg/kg)和等容量生理盐水颈静脉注射,测定其UI及胃液pH,结果：整个应激过程中血浆及胃黏膜中β－内啡肽的含量无显著变化（P＞0．05）,应激各组胃黏膜UI均显著高于未应激组（P＜0．01）,应激15分钟组胃液pH显著高于未应激组（P＜0．01）,临终前（应激8h组）胃液pH显著高于对照组（P＜0．05）,阻断阴UI及胃液pH较对照组均无显著变化（P＞0．05）,结论：应激过程中血浆及胃黏膜β－内啡肽含量稳定,阻断β－内啡肽不影响胃液pH及UI,外周β－内啡肽变化对应激所致胃黏膜损伤可能不起重要作用。     

应激诱发抑郁症机制的研究进展

慢性应激或长期使用外源性应激激素糖皮质类固醇,可以引起机体神经系统功能失调,诱导抑郁、学习和记忆障碍、衰老过程加速等。其中,应激激素对海马的选择性损伤是导致这些疾患发展的关键原因。其表现为海马出现糖皮质激素（GC）受体下调、神经元萎缩甚至缺失等退行性变化。其机制可能与GC及继发性释放的兴奋性氨基酸（EAAs)协同作用,最终使神经营养因子（如NGF）表达低下有关。本文就慢性应激诱发抑郁症机制的研究进展进行综述。     

压力应激动物模型在肿瘤中的应用和研究现状

目的就各类压力应激荷瘤动物模型的造模方法进行综述,对其特点进行评述,并分析了压力应激在肿瘤发生发展中的作用机制。方法应用计算机检索PubMed数据库（2000／2013）,以“stress,animalmodel,tumor”为检索词;检索中国知识资源总库（2000～2013）、重庆维普数据库（2000～2013）、万方数据库（2000～2013）三大中文期刊数据库,以“应激,动物模型,肿瘤”为检索词。文章所述内容需与应激动物模型的建立、应用、评价,及压力应激与肿瘤的关系等方面研究密切相关,排除重复性研究。结果共收集596篇关于应激动物模型的文献,中文156篇,英文440篇。阅读标题和摘要进行初筛,排除发表时间较早、重复及类似的研究,纳入30篇符合标准的文献。结论压力应激与肿瘤研究领域为进一步从抗焦虑、抑郁等角度筛选抗肿瘤药物提供参考。     

应激抑制淋巴细胞转化的时间效应

本研究吵缚方法使大鼠接受应激刺激,然后分别取大鼠应激３、６、１２、１８ｈ和解除束缚后１２、２４、４８、７２、９６ｈ的淋巴结、脾脏提取物和血清,与刀豆素Ａ同时加入正常大鼠肠系膜淋巴结细胞悬液中育７２ｈ后用噻唑蓝（ＭＴＴ）比色分析法检测肠系膜淋巴结细胞的转化,来应激抑制淋巴细胞转化作用的出现和消失过程。结果如下：（１）应激３和６ｈ大鼠的淋巴结、脾脏提取物和血清对淋巴细胞的转化都没有明显的影响;（２）应     

Physiological and biochemical analysis of mechanisms underlying cadmium tolerance and accumulation in turnip

The capacity of plants to accumulate cadmium (Cd) is significant for phytoremediation of Cd-polluted soils. Turnips cultivated in China include species featuring high Cd accumulation and some of these plants act as Cd hyperaccumulator landraces. These plants can accumulate over 100 mg Cd kg^-1 dry weight in leaves without injury. Hence, studies that explore mechanisms underlying Cd detoxification and transport in turnip plants are essential. In the present study, we compared physiological and biochemical changes in turnip leaves treated with two Cd concentrations to controls. We discovered that Cd stress significantly increased the enzymatic activities or compound contents in the antioxidant system, including members of the glutathione-ascorbic acid cycle, whereas oxidation of reactive oxygen species (ROS) remained stable. Cd treatments also increased the contents of phytochelatins as well as a number of amino acids. Based on these results, we conclude that turnips initiate a series of response processes to manage Cd treatment. First, the antioxidant system maintaining ROS homeostasis and osmotic adjustment is excited to maintain stability of cell osmotic potential. Cd is chelated into its stable form to reduce its toxicity. Cd is possibly transported to vacuoles or non-protoplasts for isolation. Amino acid synthesis may directly and indirectly play an important role in these processes. This study partly revealed physiological and biochemical mechanisms underlying turnip response to Cd stress and provides information on artificially increasing or decreasing Cd accumulation in turnips and other plants.     

Evidence for functional interaction between brassinosteroids and cadmium response in Arabidopsis thaliana

Plant hormones, in addition to regulating growth and development, are involved in biotic and abiotic stress responses. To investigate whether a hormone signalling pathway plays a role in the plant response to the heavy metal cadmium (Cd), gene expression data in response to eight hormone treatments were retrieved from the Genevestigator Arabidopsis thaliana database and compared with published microarray analysis performed on plants challenged with Cd. Across more than 3000 Cd-regulated genes, statistical approaches and cluster analyses highlighted that gene expression in response to Cd and brassinosteroids (BR) showed a significant similarity. Of note, over 75% of the genes showing consistent (e.g. opposite) regulation upon BR and Brz (BR biosynthesis inhibitor) exposure exhibited a BR-like response upon Cd exposure. This phenomenon was confirmed by qPCR analysis of the expression level of 10 BR-regulated genes in roots of Cd-treated wild-type (WT) plants. Although no change in BR content was observed in response to Cd in our experimental conditions, adding epibrassinolide (eBL, a synthetic brassinosteroid) to WT plants significantly enhanced Cd-induced root growth inhibition, highlighting a synergistic response between eBL and the metal. This effect was specific to this hormone treatment. On the other hand, dwarf1 seedlings, showing a reduced BR level, exhibited decreased root growth inhibition in response to Cd compared with WT, reversed by the addition of eBL. Similar results were obtained on Brz-treated WT plants. These results argue in favour of an interaction between Cd and BR signalling that modulates plant sensitivity, and opens new perspectives to understand the plant response to Cd.     

Proteomic study of β-aminobutyric acid-mediated cadmium stress alleviation in soybean

The present study highlights the protective role of β-aminobutyric acid (BABA) in alleviating cadmium (Cd) stress in soybean. Proteomic analyses revealed that out of 66 differentially abundant protein spots in response to Cd challenge, 17 were common in the leaves of BABA-primed and non-primed plants. Oxygen-evolving enhancer protein 1 and ribulose bisphosphate carboxylase small chain 1 were detected in increase abundance in both groups of leaves. Among the 15 commonly decreased protein spots, the relative intensity levels of heat shock cognate 70-kDa protein, carbonic anhydrase, methionine synthase, and glycine dehydrogenase were partially restored after BABA treatment. Moreover, BABA priming significantly enhanced the abundance of the defense-related protein peroxiredoxin and glycolytic enzymes in response to Cd exposure. Additionally, the impact of Cd on the physiological state of BABA-primed and non-primed plants was analyzed using a biophoton technique. The finding of comparatively low biophoton emission in BABA-primed leaves under Cd stress indicates that these plants experienced less oxidative damage than that of non-primed plants. Proteomic study coupled with biophoton analysis reveals that BABA pretreatment helps the plants to combat Cd stress by modulating plants' defence mechanism as well as activating cellular detoxification system to protect the cells from Cd induced oxidative stress damages.     

Modifications in endopeptidase and 20S proteasome expression and activities in cadmium treated tomato (<Emphasis Type="Italic">Solanum lycopersicum</Emphasis> L.) plants

The effects of cadmium (Cd) on cellular proteolytic responses were investigated in the roots and leaves of tomato (Solanum lycopersicum L., var Ibiza) plants. Three-week-old plants were grown for 3 and 10 days in the presence of 0.3–300 μM Cd and compared to control plants grown in the absence of Cd. Roots of Cd treated plants accumulated four to fivefold Cd as much as mature leaves. Although 10 days of culture at high Cd concentrations inhibited plant growth, tomato plants recovered and were still able to grow again after Cd removal. Tomato roots and leaves are not modified in their proteolytic response with low Cd concentrations (≤3 μM) in the incubation medium. At higher Cd concentration, protein oxidation state and protease activities are modified in roots and leaves although in different ways. The soluble protein content of leaves decreased and protein carbonylation level increased indicative of an oxidative stress. Conversely, protein content of roots increased from 30 to 50%, but the amount of oxidized proteins decreased by two to threefold. Proteolysis responded earlier in leaves than in root to Cd stress. Additionally, whereas cysteine- and metallo-endopeptidase activities, as well as proteasome chymotrypsin activity and subunit expression level, increased in roots and leaves, serine-endopeptidase activities increased only in leaves. This contrasted response between roots and leaves may reflect differences in Cd compartmentation and/or complexation, antioxidant responses and metabolic sensitivity to Cd between plant tissues. The up-regulation of the 20S proteasome gene expression and proteolytic activity argues in favor of the involvement of the 20S proteasome in the degradation of oxidized proteins in plants. This paper is dedicated to Nathalie Galtier (1964–2005), who was senior researcher at the INRA Research Center, Villenave d’Ornon, France.     

Alleviation of Cadmium Toxicity in Brassica juncea L. (Czern. & Coss.) by Calcium Application Involves Various Physiological and Biochemical Strategies

Calcium (Ca) plays important role in plant development and response to various environmental stresses. However, its involvement in mitigation of heavy metal stress in plants remains elusive. In this study, we examined the effect of Ca (50 mM) in controlling cadmium (Cd) uptake in mustard (Brassica juncea L.) plants exposed to toxic levels of Cd (200 mg L⁻¹ and 300 mg L⁻¹). The Cd treatment showed substantial decrease in plant height, root length, dry weight, pigments and protein content. Application of Ca improved the growth and biomass yield of the Cd-stressed mustard seedlings. More importantly, the oil content of mustard seeds of Cd-stressed plants was also enhanced with Ca treatment. Proline was significantly increased in mustard plants under Cd stress, and exogenously sprayed Ca was found to have a positive impact on proline content in Cd-stressed plants. Different concentrations of Cd increased lipid peroxidation but the application of Ca minimized it to appreciable level in Cd-treated plants. Excessive Cd treatment enhanced the activities of antioxidant enzymes superoxide dismutase, ascorbate peroxidase and glutathione reductase, which were further enhanced by the addition of Ca. Additionally, Cd stress caused reduced uptake of essential elements and increased Cd accumulation in roots and shoots. However, application of Ca enhanced the concentration of essential elements and decreased Cd accumulation in Cd-stressed plants. Our results indicated that application of Ca enables mustard plant to withstand the deleterious effect of Cd, resulting in improved growth and seed quality of mustard plants.     

Enzymatic response to cadmium by Impatiens glandulifera: A preliminary investigation

This paper aims to develop our understanding of the effect of cadmium (Cd) on Impatiens glandulifera, a recently identified potential Cd hyperaccumulator. Impatiens glandulifera plants were exposed to three concentrations of Cd (20, 60 and 90 mg/kg) and were sampled at two timepoints (one and seven days) to investigate the stress response of I. glandulifera to Cd. Cd can induce oxidative stress in plants, triggering overproduction of reactive oxygen species (ROS). The level of activity of catalase (CAT) and ascorbate peroxidase (APX), two crucial antioxidant enzymes responsible for detoxifying ROS, were found to increase in a concentration dependent manner. Though there was no change observed in the level of superoxide dismutase (SOD) activity, the activity of glutathione S-transferase (GST), involved in detoxifying and sequestering Cd, increased after exposure to Cd. Cd did not appear to impact the levels of proline and photosynthetic pigments, indicating the plants weren't stressed by the presence of Cd. These results suggest that the rapid response observed in enzyme activity aid the efficacious mitigation of the toxic effects of Cd, preventing significant physiological stress in I. glandulifera.     

Genotypic variation of the response to cadmium toxicity in Pisum sativum L

This work evaluates the (cor-)relations between selected biochemical responses to toxic Cd and the degree of Cd sensitivity in a set of pea genotypes. Ten genotypes were analysed that differ in their growth response to Cd when expressed as root or shoot tolerance indices (TIs). Concentrations of non-protein thiols (NPTs) and malondialdehyde (MDA), activity of chitinase, peroxidase (POX), and catalase significantly increased in all pea genotypes treated with Cd. Cd-sensitivity of genotypes was correlated with relative increases in MDA concentration as well as activities of chitinase and POX, suggesting similar Cd stress effects. Activities of ascorbate peroxidase (APX) decreased, but concentrations of glutathione (GSH) increased in the less Cd-sensitive genotypes. Differences in root and leaf contents of Cd revealed no correlation with TI, metabolic parameters, and enzyme activities in Cd-treated plants, respectively, except that shoot Cd concentration positively correlated with shoot chitinase activity. Toxic Cd levels inhibited uptake of nutrient elements such as P, K, S, Ca, Zn, Mn, and B by plants in an organ- and genotype-specific manner. Cd-sensitivity was significantly correlated with decreased root Zn concentrations. The results show both similarities, as well as distinct features, in Cd toxicity expression in genotypes of one species, suggesting that independent and multi-factorial reactions modulate Cd sensitivity on the low-tolerance level of plants. The study illustrates the biochemical basis of earlier detected genotypic variation in Cd response.     

Effect of cadmium on growth and micronutrient distribution in wild garlic (Tulbaghia violacea)

Tulbaghia violacea Harv. (Alliaceae) is one of the few medicinal plants that is also frequently used as a leafy vegetable. Application of cadmium (Cd) at 2 and 5 mg/L to T. violacea plants of various sizes (small 8–10 g, medium 16–20 g, large 80–95 g) elicited a difference in growth response, Cd accumulation and micronutrient distribution. Application of Cd up to 5 mg/L had no significant effect on growth parameters of large-sized plants while leaf length and fresh weight of leaves of the medium-sized plants decreased with application of Cd at 2 mg/L, and 5 mg/L. Cadmium significantly decreased the number of leaves in small-sized plants. Small plants accumulated more Cd in the leaves than medium or large-sized plants. Application of Cd at 2 and 5 mg/L lowered the leaf Cu, Fe, Mo and Zn contents in small and medium-sized plants but had no effect on the micronutrients in large-sized plants. This study indicates that T. violacea has the ability to accumulate Cd. In addition, plant size plays an important role with regards to Cd accumulation and elemental distribution. The results presented in this study include the first report on the nutritional status of T. violacea leaves.