玉米叶片受新月弯孢菌侵染后的细胞病理学变化

 本文利用透射电子显微镜技术与细胞化学技术研究了玉米叶片受弯孢菌侵染后的超微结构和细胞壁的组成成份变化。透射电镜观察发现,病菌侵入后,菌丝先在寄主细胞间扩展,随着寄主细胞病变、坏死,菌丝可进入寄主细胞形成胞内菌丝。随病菌侵入和在寄主体内扩展,寄主细胞先后发生了一系列的超微结构变化,叶绿体、液泡等细胞器解体,出现质壁分离现象,并最终解体、坏死、变形。细胞化学标记定位发现,受侵寄主细胞壁中纤维素、木聚糖和果胶质的标记密度明显低于未接种的健康组织,表明细胞壁降解酶(如纤维素酶、木聚糖酶和果胶酶)的产生与病菌侵染和致病过程密切相关。     

稻-鸭生态系统中二化螟消长动态研究

2003年4～10月,在稻鸭共栖田中,对二化螟发生规律的系统研究结果表明,稻田养鸭能显著减轻二化螟的为害。与对照相比,中稻田养鸭区二化螟为害株率减少13.4%～47.1%;晚稻田减少62.2%。稻鸭共栖能减少化学农药的使用量,具有较好的经济、社会和生态效益。     

氮素水平对单作和间套作小麦玉米叶片叶绿素含量及品质的影响

以间套作小麦玉米、单作小麦和单作玉米为研究对象,通过田间试验研究了氮素水平对单作和间套作小麦玉米叶片叶绿素及品质的影响。主要结果为:在同一施氮水平下,间套作小麦旗叶叶绿素含量大于相应单作;单作和间套作小麦开花期旗叶叶绿素含量和蛋白质含量、沉淀值之间都呈显著正相关(r分别为0.960*,0.948*,0.968*,0.957*)。在相同施氮水平下,单作玉米叶绿素含量高于相应间套作玉米;单作和间套作玉米孕穗期叶绿素含量与其蛋白质含量之间也呈显著正相关(r分别为0.861*和0.870*)。     

Cortical gene expression pattern in rat focal cerebral ischemia

AIM: To investigate the genes differential expression in cortex during rat focal cerebral ischemia.METHODS: cDNA microarray chips containing numerous cDNAs were used to investigate the gene expression pattern between samples of focal cerebral ischemia and sham-control operation rats. RESULTS: Two hundred and eleven genes differentially expressed were screened out, among these genes, up-and down-regulated genes were 199 and 12, respectively. CONCLUSIONS: The analysis of gene expression pattern of focal cerebral ischemia based on cDNA microarray can realize high-throughput screening of the genes associated with the focal cerebral ischemia. The differential expression of genes may be related to the pathogenesis of focal cerebral ischemic diseases.     

Antitumor effect of chlorophyllin in vitro

AIM: To study the effect and mechanism of chlorophyllin (CHL) inhibiting HT29 cells. METHODS: IC₅₀ value and growth curve of HT29 cells were detected with MTT method. Apoptosis was detected with Wright-Giemsa staining, FCM and DNA electrophoresis. Telomerase was detected by PCR-ELISA, and protein and mRNA expression of COX-2 gene were detected through RT-PCR and Western blot. RESULTS: CHL inhibited the growth of HT29 in a dose-dependent manner. CHL blocked HT29 cells in G₁ phase but did not induce apoptosis. Different concentration of CHL inhibits the expression of telomerase and COX-2 in HT29 cells. CONCLUSION: CHL inhibited the growth of HT29 cells by inhibiting the expression of telomerase and COX-2 and blocking cells in G₁ phase.     

Expression of cyclooxygenase-2 in IL-1β-stimulated mesangial cells is medicated by NF-κB/IκB signal pathway

AIM: To investigate the role of NF-κB/IκB signal pathway in the regulation of cyclooxygenase-2 (COX-2) expression in human mesangial cells (HMC). METHODS: The PGE₂ concentration in supernatants of HMC was measured by radioimmunoassay. COX-2 mRNA and protein expression were determined by RT-PCR and Western blot. Electrophoretic mobility shift assay (EMSA) and Western blot were used to detect the activity of NF-κB and degradation of IκB. RESULTS: IL-1β significantly upregulated COX-2 expression and PGE₂ production in HMC. Significant up-regulation of NF-κB activation, nuclear translocation of p65 subunit, and degradation of IκB α and IκB β were observed in IL-1β-induced HMC. CONCLUSION: Expression of COX-2 in IL-1β-induced HMC is mediated by NF-κB/IκB signal pathway.     

我国近年来水稻重大病虫害可持续控制技术重要研究进展——非化学控害技术研究

针对水稻病虫害防治中长期存在控害保产与生产无公害稻米矛盾比较突出的问题,研究提出了几种效果显著的非化学控害增产技术。其中,利用水稻遗传背景、对病虫抗感水平等差异显著的水稻品种多样性种植,控制稻瘟病的效果达42.12％～76.68％,抑制白背飞虱若虫数量增长效果明显,增产糯稻或优质稻600～1050 kg／hm²,平均增收约1 500元／hm²;稻鱼共育控制稻飞虱的效果为63.77％～86.89％,对纹枯病病株抑制率70.52％,控制稻田杂草效果为89.57％,平收获鲜鱼319.5～1 177.5 kg／hm²,水稻产量比对照区增产7.05％～10.11％;稻鸭共育控制稻飞虱效果63.73％～77.18％,控制稻螟效果30.11％,控制纹枯病效果19.33％～67.03％,对稻田杂草控制效果91.96％,减少施肥30.6％、农药59.3％,减少投入1 987.05元／hm²。     

日本刀角瓢虫形态特征及生物学特性研究

日本刀角瓢虫是粉虱类害虫的重要捕食性天敌之一、本文详细地描述了日本刀角瓢虫的形态特征，并附有各虫态的特征图。且对日本刀角瓢虫的生活习性进行了观察、以烟粉虱卵为食料，日本刀角瓢虫世代发育历期平均为22．56天，成虫平均寿命为9l94天，平均每雌产卵量为564．8粒：以烟粉虱若虫为食料，日本刀角虫世代发育历期平均为21．70天，成虫平均寿命为81．62天，平均每雌产卵量为650．0粒：瓢虫可捕食烟粉虱的卵、若虫、“蛹”、成虫各虫态，是烟粉虱的有效天敌，具有很好的保护利用价值。     

引诱剂在综合防治桔小实蝇作用中的评估

以使用引诱剂为主 ,坚持在杨桃园挂引诱笼 2 - 3年后 ,大量降低田间桔小实蝇BactroceradorsalisHendel雄虫数量和卵的受精率 ,配合其它的综防措施 ,防效逐年提高。三个综防点试验实践表明 :杨桃每果虫口数 ,卵孵化率及受害果率大大降低 ,防效达 92 5%。对桔小实蝇的防治初见成效。