猴免疫缺陷病毒引起多形核嗜中性白细胞凋亡的可能机理（英文）

本实验目的是研究猴免疫缺陷病毒(SIV)引起多形核嗜中性白细胞(PMNs)凋亡的机理.实验用PCR技术扩增gag基因,用Western blot法测定p53和bcl-2基因的表达.结果显示PMNs在被SIV感染后随着保温时间的延长存活率下降,在感染后24h可以从PMNs中扩增出gag基因.PMNs中p53基因的的表达在感染后24h增加.同时bcl-2基因的表达在对照组和SIV感染组都增加,但在SIV感染组bcl-2蛋白的表达明显低于对照组.结果揭示SⅣ能够感染PMNs,p53和bcl-2基因表达的改变可能是SⅣ感染PMNs引起细胞凋亡的机理.     

猴免疫缺陷病毒引起多形核嗜中性白细胞凋亡的可能机理

本实验目的是研究猴免疫缺陷病毒(SIV)引起多形核嗜中性白细胞(PMNs)凋亡的机理.实验用PCR技术扩增gag基因,用Western blot法测定p53和bcl-2基因的表达.结果显示PMNs在被SIV感染后随着保温时间的延长存活率下降,在感染后24h可以从PMNs中扩增出gag基因.PMNs中p53基因的的表达在感染后24h增加.同时bcl-2基因的表达在对照组和SIV感染组都增加,但在SIV感染组bcl-2蛋白的表达明显低于对照组.结果揭示SⅣ能够感染PMNs,p53和bcl-2基因表达的改变可能是SⅣ感染PMNs引起细胞凋亡的机理.     

斜纹夜蛾核型多角体病毒DNA诱导同源昆虫细胞的凋亡

发现野生型斜纹夜蛾核型多角体病毒（Spodoptera litura nuclear polyhedrosis virus,SpltNPV）DNA转染SL-1细胞能诱导细胞凋亡.SpltNPV-DNA转染其同源细胞系斜纹夜蛾核SL-1细胞6 h后,光镜下即可见细胞膜表面突出或形成小泡,细胞碎裂成凋亡小体,18 h后,细胞100%碎裂成凋亡小体.DAPI荧光染色显示感染细胞核渐呈半月形,直至碎裂被凋亡小体包裹.被转染的SL-1细胞DNA琼脂糖凝胶电泳呈典型梯形谱带.野生型SpltNPV病毒粒子感染的SL-1细胞既无多角体的出现,也无凋亡现象的发生.     

AcMNPVie—1基因诱导的斜纹夜蛾细胞凋亡

苜蓿丫纹夜蛾核多角体病毒 (Autographacalifornicamulticapsidnucleopolyhedrovirus,AcMNPV)感染可诱导斜纹夜蛾 (Spodopteralitura)离体细胞Sl zsu 1发生典型的细胞凋亡。通过细胞松弛素 (cytochalasinD)和NH4Cl的抑制实验 ,分别排除病毒粒子结合细胞受体蛋白 ,和病毒在核内体运输过程启动细胞凋亡信号发生的可能性。RT PCR实验证实 ,病毒基因组进入了细胞核 ,极早期基因ie 1开始了转录 ;而DNA聚合酶抑制剂 (芽栖菌素 )的存在对病毒诱导的细胞凋亡程度与进程均没有明显的影响。这说明细胞凋亡的信号是先于病毒晚期复制事件启动的。单独转染AcMNPV极早期基因ie 1可诱导斜纹夜蛾离体细胞系Sl zsu 1细胞发生部分凋亡 ,转染 2 4h后出现凋亡小体 ,4 8h达到高峰。提取转染细胞的总DNA电泳 ,可检测到典型的DNA梯形条带 (DNAladder)。另外 ,AcMNPV的ie 1基因温度敏感突变株tsB82 1在非受纳温度感染细胞时 ,细胞不发生凋亡。这些结果暗示 ,在AcMNPV感染诱导的Sl zsu 1细胞凋亡中 ,ie 1基因是一个凋亡信号的直接或间接诱导因子。     

汉滩病毒诱导小鼠骨髓瘤SP2/0细胞凋亡的初步研究

为研究汉滩病毒对肿瘤细胞的诱导凋亡作用,以一定量病毒悬液感染体外培养的SP2/0细胞,接种后定时间将细胞消化甩片行Gimsa染色观察凋亡细胞核的变化,制细胞悬液以流式细胞仪测细胞周期,并用免疫组化的方法检测凋亡分子Fas和FasL的表达.结果示经病毒诱导后细胞出现生长特性及形态学变化,Giemsa染色观察到典型凋亡细胞;流式细胞仪显示有凋亡峰出现;免疫组化检测出感染后SP2/0细胞中Fas和FasL表达明显升高.该结果表明汉滩病毒可诱导体外培养SP2/0细胞凋亡,其发生可能与凋亡分子Fas和FasL有关.     

猴免疫缺陷病毒引起多形核嗜中性白细胞凋亡的可能机理

本实验目的是研究猴免疫缺陷病毒（SIV）引起多形核嗜中性白细胞（PMNs）凋亡的机理。实验用PCR技术扩增gag基因,用Western blot法测定p53和bcl-2基因的表达。结果显示PMNs在被SIV感染后随着保温时间的延长存活率下降,在感染后24h可以从PMNs中扩增出gag基因。PMNs中p53基因的表达在感染后24h增加。同时bcl-2基因的表达在对照组和SIV感染组都增加,但在SIV感染组bcl-2蛋白的表达明显低于对照组。结果揭示SIV能够感染PMNs,p53和bcl-2基因表达的改变可能是SIV感染PMNs引起细胞凋亡的机理。     

鸭呼肠孤病毒强毒株致鸭胚原代成纤维细胞凋亡的研究

通过光镜、电镜、DNA Ladder法、流式细胞术、荧光染色对鸭呼肠孤病毒(DRV)诱导鸭胚原代成纤维细胞(DEF)凋亡情况进行检测.结果显示,光镜可见细胞形态学上出现细胞皱缩,染色质浓染边移;电镜观察到细胞胞浆浓缩,细胞核染色质凝聚、部分形成凋亡小体;荧光染色结果显示,在感染后24h有激发绿色荧光的凋亡细胞出现,随着时间的推移,激发红色荧光的死亡细胞数量增多;DNA Ladder检测到感染后24～144h的DNA样品呈梯形条带;流式细胞术于感染后24h检测到凋亡细胞,其数量在72～96h达到高峰,144h开始下降.研究结果表明,DRV在DEF增殖的过程中具有诱导宿主细胞凋亡的作用.     

HSV-1感染对人星形胶质瘤细胞增殖、凋亡和细胞周期的影响

目的:研究单纯疱疹病毒1型(Herpes simplexvires,HSV-1)感染对人星形胶质瘤细胞U251增殖、凋亡和细胞周期的影响.方法:以感染复数(MOI)为5的HSV-1感染体外培养的U251细胞,在感染后24 h、48 h、72 h和96 h用倒置显微镜观察U251细胞的形态改变:用MTT法、流式细胞术观察HSV-1感染对U251细胞增殖、凋亡和细胞周期的影响.结果:①U251细胞在感染24h后开始出现细胞融合,48 h后开始出现典型的细胞病变效应(Cytopathic effect,CPE),72h后超过80%的细胞出现CPE,.96h后细胞大部分死亡.②MTT法显示HSV-1感染U251细胞24 h、48 h、72 h及96 h的U251细胞OD值均低于对照组(P<0.05).③HSV-1感染U251细胞12h后凋亡率与对照组无显著差异(P0.05),感染24h和36h后凋亡率比相应对照组有显著差别(p<0.05).④HSV感染12h、24h和36h后均可引起U251细胞S期细胞增多和G0/G1期细胞减少,24 h后G2/M期细胞比例开始增加.结论:HSV.1能感染体外培养的U251细胞,抑制其增殖,促进其凋亡并影响其细胞周期.     

口蹄疫病毒前导蛋白(Lpro)致牛肾细胞(MDBK)作用的形态学观察

为探讨口蹄疫病毒Lpro致MDBK细胞病变效应中的形态学变化,本实验在成功构建可稳定表达口蹄疫病毒Lpro目的基因的MDBK细胞系的基础上,人工诱导Lpro表达后,采用光学显微镜观察、Hoechst33258染色、AO-EB染色、DNALadder等进行检测,研究口蹄疫病毒Lpro致MDBK细胞的病变效应。结果显示,MDBK细胞系在诱导表达口蹄疫病毒Lpro24h后,光学显微镜下细胞形态表现为细胞体积缩小、核浓缩、细胞周围出现透明圈等现象;Hoechst33258染色检测呈现典型的细胞核浓缩和梅花状核碎裂;诱导表达Lpro36h后,AO-EB染色显示早期病变细胞核染亮绿色呈致密斑块或碎片状,晚期病变细胞核染橘黄色呈致密斑块;DNA凝胶电泳显示可见的DNALadder"梯状"条带。证明口蹄疫病毒Lpro在体外可诱导MDBK细胞发生凋亡。     

Sindbis病毒的繁殖与宿主细胞BHK—21的凋亡

详细报道了Sindbis病毒诱导BHK-21细胞凋亡的过程,病毒感染6h后即可观测到核染色质的断裂,病毒感染12h后染色质可见明显的凝集,感染后24h DNA电泳出现明显的DNA“阶梯”(DNA ladder)。电镜观察更清楚地显示了凋亡小体形成的某些细节:在染色质凝集处核外膜突起,最后与细胞核分离形成凋亡小体。在此基础上将一段病毒非结构蛋白nsP2基因克隆到真核表达载体pMAMneo中,并得到瞬间表达,在其中一些细胞中出现DNA断裂这一细胞凋亡的基本特征,通过对nsP2氨基酸序列的分析,结合以前的实验结果推测nsP2可能与诱导细胞凋亡直接相关。     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.