水稻叶片衰老基因LPS1的克隆与功能研究

【目的】早衰突变体是研究早衰机制的良好载体,对于探究早衰的遗传机理与作用机制及提高水稻的产量和品质具有重要作用。【方法】本研究利用EMS诱变获得了一个早衰突变体lps1,并对该突变体及其野生型进行表型观察、细胞学及组织化学分析、生理生化分析、遗传分析、基因定位和激素处理。【结果】lps1的叶片从3叶期开始发黄,成熟期株高、有效分蘖数、结实率、千粒重等极显著降低。电镜观察发现lps1叶表面光滑,硅质化突起和叶绿体数目减少、片层结构紊乱。生理生化分析表明lps1中有大量的活性氧积累,同时伴有蛋白质的降解、细胞膜的损伤以及大规模的细胞死亡。遗传分析表明该早衰表型受单隐性核基因控制,并且其在第5染色体上编码了一个泛素结合酶。亚细胞定位结果证明LPS1蛋白在细胞质与核中均有表达。外源激素处理发现,lps1对外源激素的处理更为敏感,且LPS1突变促进了ABA合成相关基因的表达。【结论】LPS1 突变使水稻ABA合成信号途径异常,进而引发H₂O₂等一系列与衰老相关生理指标的异常变动,导致lps1过早衰老,最终造成水稻产量严重降低。     

Omega-3 fatty acids in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

BACKGROUND: Omega-3 fatty acids have been shown to reduce arrhythmia in animal models and people. These effects have not been studied in dogs with spontaneously occurring arrhythmia. HYPOTHESIS: Fish oil will reduce the frequency of ventricular arrhythmia in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC). ANIMALS: Twenty-four Boxers with ARVC were included in this study. METHODS: Asymptomatic Boxers not receiving antiarrhythmic medications were evaluated with echocardiogram and electrocardiogram. Dogs with at least 1 ventricular premature contraction (VPC) received 24-hour ambulatory electrocardiography (AECG) recordings. Dogs with > 95 VPCs in 24 hours were randomized to 1 of 3 treatments: (1) Fish oil, 2 g; (2) Flax oil, 2 g; or (3) sunflower oil, 2 g (Control group), for 6 weeks. Investigators and owners were blinded to the treatment groups. All baseline measurements were repeated after the 6-week supplementation. RESULTS: There were no differences at baseline for age, sex, blood pressure, weight, echocardiographic measurements, or VPCs. Median number of VPCs in 24 hours for all dogs was 543 (range, 96-40,063) at baseline and 193 (range, 6-14,825) after 6 weeks of supplementation. VPCs/24 h were reduced for the Fish oil group (baseline median = 397 [range, 249-10,587]; 6-week median = 162 [range, 16-3,781]; P = .02), but not for the Flax oil (P = .58) or Control (P = .48) groups. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that fish oil, but not flax oil, supplementation for 6 weeks reduces arrhythmia in Boxers with ARVC and that it could be useful in treating this common disease. Further studies are needed to determine optimal dose and duration of treatment.     

动态心电图检测冠心病患者早搏的临床意义

对冠心病组９６例和健康人组５２例的频发性早搏（≥３０次／小时）作对比分析后发现：（１）室性早搏多出现在早上５～１０时（５．３％～１２．３％），两组差异不显著，但冠心病的室性早搏，级别比健康人对照组明显高（Ｐ＜０．０１）。（２）室上性早搏合并短阵快速性心律失常是冠心病的表现之一（占６９．６％），而健康对照组仅１例（１．９％）合并短阵房速，两者差异显著（Ｐ＜０．００１）；（３）同时伴两种频发早搏者也是冠心病的征象之一。     

玉米早衰影响因素及其调控措施

介绍了玉米叶片及根系早衰的主要影响因素：品种自身遗传、气象环境与土壤肥力以及种植模式、栽培措施等,从宏观以及内在机制上阐述了早衰对玉米产量的显著影响。同时总结了早衰的防治方法,提出了具体的调控措施。除了从品种选育及使用合理的栽培措施调控外,还重点介绍了采用植物生长调节剂调控玉米生长发育进而延缓衰老的措施,并对未来玉米早衰的防治措施进行了展望。     

极早熟玉米重组群体籽粒脱水速率差异的初步研究

为培育生理成熟后籽粒脱水快的玉米品种,解决玉米收获期含水量过高的问题,以德美亚♂(脱水快)×边自30(脱水慢)组配的100个重组自交系群体为材料,对生理成熟后籽粒自然脱水速率进行方差分析和遗传力估计,比较重组自交系生理成熟后籽粒自然脱水速率的差异。结果表明:家系间籽粒自然脱水速率差异达到极显著水平,且籽粒自然脱水速率表现较高的遗传能力,广义遗传力为76.93。同时对籽粒脱水速率进行了正态分布检测,检测结果符合正态分布。     

棉花生理性早衰研究进展

由于自身或外部原因使棉株在有效的生长季节内局部或整体提早结束生命而影响棉花产量和品质形成的现象即为早衰。早衰有病理性和生理性两种,皆表现为棉株体局部或整体过早衰败,经济性状受损。棉花生理性早衰既有品种原因,也与气候条件、土壤地力、肥水管理等外部因素等有关。结合现有研究,总结提出了生理性早衰成因的矿质营养失调说、库源失调说、激素失衡说和外源基因耗能说4种解释。     

早产儿配方乳储藏过程中物理性质变化研究

本文对早产儿配方乳储藏过程中物理性质的变化进行了研究。将早产儿配方乳分别在25℃和40℃下储藏35 d,每7 d进行物理性质测定,包括粒径、Zeta电位、黏度、色差(ΔE)、酸度和pH值。结果表明,储藏期间早产儿配方乳的粒径、ΔE、酸度呈逐渐增大趋势,Zeta电位的绝对值、黏度和pH值呈逐渐降低趋势,并且在40℃储藏时,变化速度比25℃快。本研究为早产儿配方乳储藏过程品质保持、储运条件的选择及货架期的预测提供了参考。