昆虫热休克蛋白的研究概况

所有生物体相应于高温和其它胁迫环境都会产生一特定的被称为热休克蛋白的应急蛋白。该文对国内外有关昆虫热休克蛋白的研究做了简要综述。尽管热休克蛋白是在高温胁迫研究中发现的 ,但是后来发现在低温、氨基酸类似物、低氧、ABA、2 ,4-二氯苯氧乙酸等环境下 ,同样会有热休克蛋白的生成。这一发现暗示着热休克蛋白的功能可能会很多。已经报道的有分子伴侣 ,耐热性 ,耐冷性以及在昆虫发育过程和细胞代谢中生化作用的特殊功能等。     

果蝇的热休克反应

热休克反应最早在果蝇中发现,其过程伴随着一系列特殊蛋白--热休克蛋白（HSPs）的增量表达.热休克蛋白包括多个家族,它们在热休克反应中表现出复杂的表达调控机制,并具有组织和发育阶段特异性.研究热休克反应具有重要的生物学意义,在医学、工业等的应用前景十分广阔.     

真菌HSP30的研究概况

热休克蛋白30是小分子热休克蛋白(small heat shock proteins,sHSPs)中的一种,也是真菌中研究最广泛的小分子热休克蛋白。多种真菌编码热休克蛋白的基因序列已经被克隆和检测,HSP30的研究主要集中在应激水平下的表达和转录水平的调控,HSP30在应激反应中的合成机制仍不是很清楚,综述了它的研究概况以及应用前景。     

微生物产生的冷休克蛋白研究进展

冷休克蛋白(cold shock protein,Csp)首先在大肠杆菌中发现,它与微生物对冷环境的适应及多种细胞功能有关。冷休克蛋白基因是一段编码70个左右氨基酸的DNA序列,在这段序列中有5′非翻译区(5′UTR)、冷盒及下游盒等特征。冷休克蛋白作为DNA或RNA结合蛋白在基因表达调控过程中起重要作用。冷休克蛋白在转录、mRNA稳定性及翻译等几个水平上被严格调控。     

昆虫的热休克反应和热休克蛋白

热休克（热激heatshock）是指短暂、迅速地向高温转换所诱导出的一种固定的应激反应。诱导该反应的温度在种与种之间有所不同。热休克反应最明显的特征是：伴随着正常蛋白质合成的抑制,一部分特殊蛋白质的诱导和表达增加,即为热休克蛋白（heatshockproteins,HSPs）。尽管热休克蛋白的合成也能被其它形式的应激反应所诱导,将它们认为是应激蛋白可能更恰当,但人们习惯上仍将这类蛋白质称为热休克蛋白。由于热休克反应和热休克蛋白是在果蝇（Drosophiliamelanogaster）中最初发现的,故在昆虫中,特别是果蝇等双翅目昆虫中研究得较深入…     

热休克反应中蛋白质合成抑制的机制

热休克反应中蛋白质合成抑制的机制郭兴中徐仁宝（第二军医大学病理生理学教研室,上海２００４３３）关键词热休克反应翻译剪接生物体在不利环境如热休克等各种应激情况下,细胞内分子水平的反应主要是热休克蛋白基因的大量、快速、短暂地表达,因而产生大量热休克蛋白（...     

热休克蛋白对细胞凋亡信号转导途径的调节

细胞凋亡信号转导目前已迅速成为揭示细胞凋亡分子机制的前沿课题. 由于热休克蛋白(HSPs)在细胞生长调控和凋亡中发挥的重要作用, 人们进行了大量关于热休克蛋白与细胞凋亡信号转导途径调节机制的研究. 研究发现, 热休克蛋白家族的多个成员, 如HSP90, HSP70, HSP60, HSP27等能够在Fas死亡受体途径、JNK/SAPK途径、caspase途径等多个水平发挥调节作用, 并且部分依赖于热休克蛋白的“分子伴侣”作用, 控制着细胞生命进程.     

昆虫滞育关联热休克蛋白的研究进展

滞育是昆虫逃避不利环境条件的基本方式之一, 益虫的合理利用和害虫的综合治理, 都离不开对滞育调控机理的研究。滞育可以诱导一些基因表达模式的改变, 如热休克蛋白基因的差异表达, 导致昆虫抗逆性增强。本文综述了与昆虫滞育关联的热休克蛋白的研究概况, 从热休克蛋白与滞育的关联、 不同虫态滞育期间热休克蛋白基因的差异表达和滞育相关的蛋白质组学研究几个方面进行了概述。与其他的胁迫反应均诱导热休克蛋白同步上调表达不同, 热休克蛋白在不同种类昆虫以及同种昆虫的不同滞育生理阶段的表达模式差别很大。热休克蛋白在滞育期间的表达是决定越冬抗逆性和存活的重要因子之一。本文可为昆虫滞育如何应答环境条件刺激的研究提供参考信息。     

热休克蛋白70:生物学功能与作用机制研究进展

热休克蛋白是一类广泛存在于原核生物和真核生物体内且结构上高度保守的蛋白质。有机体在应激条件下,为克服压力会诱导其表达,因此,热休克蛋白又被称为应激蛋白。作为进化上最保守的蛋白质之一,热休克蛋白70 (heat shock protein 70, Hsp70)是生物细胞中含量最高的一种热休克蛋白,可诱导性最强,具有多种生物学功能,因此,又被称为主要热休克蛋白。由于蛋白质是细胞重要成分之一,几乎涉及所有的生物学过程,Hsp70家族成员控制着细胞蛋白质稳态的所有方面,因此,Hsp70一直是科学研究的热点之一。该文概括了近年来Hsp70的生物学功能和作用机制研究进展,并对该领域的研究进行了展望。     

麻醉对大鼠应激反应的影响

用40、42、44℃分别处理清醒状态和麻醉状态大鼠30min,于正常饲养条件下恢复24h后,检测其肝脏热休克蛋白70（HSP70）的表达差异及酸性和中性蛋白水解酶活性变化。结果表明,当热休克温度为40-44℃时,清醒状态大鼠肝脏的HSP70合成能力逐渐下降,而麻醉大鼠肝脏HSP70合成能力逐渐增加,在42℃热休克条件下,麻醉状态大鼠肝脏的酸性蛋白水解酶活性最强,在44℃热休克条件下,清醒状态大鼠肝脏的酸性蛋白水解酶活性最强,在40-44℃热休克条件下,麻醉状态和清醒状态大鼠肝脏的45kD中性蛋白水解酶活性与对照相似,但40kD的中性蛋白水解酶活性随热休克温度升高而降低,另外,40℃热休克诱导麻醉状态大鼠肝脏出现一个高活性的35kD中性蛋白水解酶,根据实验结果推测,麻醉状态大鼠肝脏的热耐受性大于清醒大鼠,大鼠的热休克反应受整体水平和细胞水平的双重调控,并涉及除HSP70合成以外的其他生化活动。     

<Emphasis Type="Italic">In vitro</Emphasis>effects of relaxin on gene expression in porcine cumulus-oocyte complexes and developing embryos

Background  

Relaxin hormone peptide is found in porcine follicular and utero-tubal fluids, but its possible actions during early embryo development are still undetermined. Here, we investigated the effects of porcine relaxin during oocyte maturation and embryo development, and gene expression in the pig.     

He—Ne激光辐照天使鱼胚胎导致畸变

采用He—Ne激光(632.8nm辐照了天使鱼(Pterophyllum eimeki)的发育阶段的胚胎,观察和分析激光辐照对胚胎发育的致变影响和各发育阶段胚胎对激光的受激反应。对受精卵、囊胚期、原肠期和神经胚期的胚胎进行照射,均引起各期胚胎的畸变,这些畸变大多数是初孵仔鱼的头部、尾部、胸腔和背脊的变形。实验结果表明,天使鱼各个发育阶段的胚胎畸变率随着激光辐照剂量的改变而发生变化。     

Influence of progesterone on oocyte quality and embryo development in cows

In cattle, the majority of embryo loss occurs very early during pregnancy (approximately Day 16), around or prior to maternal recognition of pregnancy. The actions of P4 in controlling LH pulsatility and ovarian follicular development may impinge negatively on oocyte quality. A considerable proportion of embryo loss may be attributable to inadequate circulating progesterone (P4) concentrations and the subsequent downstream consequences on endometrial gene expression and histotroph secretion into the uterine lumen. Conceptus growth and development require the action of P4 on the uterus to regulate endometrial function, including conceptus-maternal interactions, pregnancy recognition, and uterine receptivity for implantation. This review summarizes recent data highlighting the role of progesterone in determining oocyte quality and embryo development in cattle.     

Influence of progesterone on oocyte quality and embryo development in cows

In cattle, the majority of embryo loss occurs very early during pregnancy (approximately Day 16), around or prior to maternal recognition of pregnancy. The actions of P4 in controlling LH pulsatility and ovarian follicular development may impinge negatively on oocyte quality. A considerable proportion of embryo loss may be attributable to inadequate circulating progesterone (P4) concentrations and the subsequent downstream consequences on endometrial gene expression and histotroph secretion into the uterine lumen. Conceptus growth and development require the action of P4 on the uterus to regulate endometrial function, including conceptus–maternal interactions, pregnancy recognition, and uterine receptivity for implantation. This review summarizes recent data highlighting the role of progesterone in determining oocyte quality and embryo development in cattle.     

Insulin-like growth factor-I promotes resistance of bovine preimplantation embryos to heat shock through actions independent of its anti-apoptotic actions requiring PI3K signaling

For the bovine preimplantation embryo, insulin-like growth factor-I (IGF-I) is a survival factor that blocks the induction of apoptosis and reduces the decrease in development caused by heat shock. The first objective was to determine the signaling pathways whereby IGF-I acts to increase embryo cell number while inhibiting heat-shock induced apoptosis. Exposure of embryos to heat shock reduced cell number and increased percent apoptosis, but IGF-I increased cell number and blocked induction of apoptosis caused by heat shock. Actions of IGF-I to increase cell number were blocked by treatment with the mitogen activated protein kinase kinase (MAPKK) inhibitor PD 98059 whereas the phosphatidylinositol 3-kinase (PI3K) inhibitor LY 294002 had no effect. Conversely, LY 294002 but not PD 98059 blocked actions of IGF-I to inhibit induction of apoptosis caused by heat shock. The second objective was to determine whether IGF-I blocks effects of heat shock on development to the blastocyst stage by preventing apoptosis. Culture of embryos with IGF-I was effective in blocking the reduction in blastocyst development caused by heat shock-this action occurred even in the presence of LY 294002. Addition of another inhibitor of apoptosis, the caspase-3 inhibitor z-DEVD-fmk, did not mimic the protective effects of IGF-I on blastocyst development. Surprisingly, IGF-I was not effective in blocking the reduction in blastocyst development caused by heat shock when cultured with z-DEVD-fmk. In conclusion, the anti-apoptotic actions of IGF-I require PI3K signaling while actions to promote proliferation require MAPKK signaling. Moreover, actions of IGF-I to allow heat-shocked embryos to continue development to the blastocyst stage are independent of its anti-apoptotic effects.     

Exogenous hyaluronic acid enhances porcine parthenogenetic embryo development in vitro possibly mediated by CD44

Exogenous hyaluronic acid (HA) has been reported to improve early embryo development in vitro in pigs and cows. Although early embryo development in vitro is improved by exogenous HA, the mechanism mediating the action of HA is not clearly defined. In the present study, two possible HA actions on early embryo development were proposed to understand interactions between HA and the embryos using porcine parthenotes. We hypothesized that improvement of early embryo development mediated by HA would be caused by embryo-derived growth factors due to the high molecular weight of HA or cellular response through its receptor (CD44). We examined the effects of HA molecular weight on parthenogenetic embryo development, permeability of HA into the zona pellucida, expression of CD44 in porcine parthenotes at various stages, and blocking interactions between HA and CD44 by monoclonal anti-CD44 antibody (mCD44Ab). As a result, although development of porcine parthenotes to the blastocyst stage was significantly enhanced by exogenous HA with various molecular weights, there was no difference in blastocyst formation among the various molecular weights (P < 0.05). Immunofluorescence revealed that exogenous HA was accessible to CD44 through the zona pellucida, irrespective of the oocyte activation and that CD44 was also expressed in both oocytes and parthenotes at all developmental stages. In addition, development of parthenotes was partially blocked by mCD44Ab. In conclusion, we demonstrated that exogenous HA enhanced development of porcine parthenotes in vitro. This improvement mediated by exogenous HA on parthenogenetic embryo development was possibly caused by cellular response via CD44.     

In vitro development of bovine morulae in bovine serum albumin, normal steer serum and uterine flushings

One hundred fifty-three excellent and good bovine morulae were cultured in Ham's F-10, supplemented with 10 % steer serum, bovine serum albumin, or uterine flushings (64 mg protein/ml) to compare embryo development. Embryos were observed every 12 h in culture. Treatment differences were evaluated by assigning a numerical value of 0 to 4 to each embryo representing the stage of development reached in vitro. The final morphological developmental score of the embryos was comparable for steer serum (2.66) and bovine serum albumin (2.50), but it differed significantly for uterine flushings obtained from ovariectomized, steroid-supplemented cows (< 0.1) or heat-treated uterine flushings (0.07). Since albumin alone was able to support development, it suggests that the albumin component of steer serum may be responsible for the observed development. Uterine fluids were unable to support growth of embryos, suggesting that incompatibility may be due to asynchrony between the early bovine embryo and uterine constituents, or a concentration of uterine components may exacerbate actions of inhibitory substances.     

Rhythmical contractile activity of amnion in embryogenesis of reptiles and birds

Rhythmical contractile activity of amnion accompanies development of reptiles and birds in the course of a large part of embryogenesis. These rhythmical contractions are myogenic and spontaneous. The strength, frequency, and character of the amnion contractions change in embryogenesis in a regular way. This type of rhythmical activity is sensitive to many neurotransmitters and external factors. Features of similarity and difference of the amnion rhythmical contractile activity in the reptile and bird embryogenesis are considered. There are discussed a possible functional significance of this rhythmical activity and its participation in response of embryo to external actions, such as temperature fluctuations and acute hypoxia.