SMV种传特性及其田间流行的种子传毒率预测

SMV感染供试品种种子传毒率最高为29.60％,最低1.04％。SMV弱毒株系的传毒率高于其强毒株系。大豆品种营养生长的V_4时期以前感染SMV种子传毒率最高,花期感染种传率显著下降。供试品种中,有初花期感病种子即不传毒;有盛花期感病仍有很低的种传率;亦有结荚初期感病还有很低种传率的品种。SMV流行的收获种子传毒率高低主要取决于大豆营养生长和花期田间病株率的高低。根据品种间早期感染SMV的最高种传率不同、花期感染种传率显著下降的特性,建立了SMV田间流行的种子传毒率预测模型。     

High-level expression and secretion of a lysine-containing analog of Escherichia coli heat-stable enterotoxin'

The mechanism of action of the heat-stable enterotoxin STa secreted from enterotoxigenic forms of Escherichia coli has remained elusive, in part due to a tedious, low-yield purification procedure. We report here a method for obtaining large amounts of a biologically active lysine-containing analog of STa. Initial attempts to express the toxin using an expression vector that did not encode a signal sequence resulted in no biologically active material being recovered either from lysed cells or as a secretory product. However, use of the secretion vector pJAL36, which contains the STII enterotoxin signal sequence, allowed large amounts of an STa derivative containing the additional sequence Ser-Thr-Lys at the amino terminus of the mature enterotoxin to be readily purified from culture supernatants. This enterotoxin analog, known as KSTa-1, was equal in biological and receptor binding activity to the native toxin STa. The lysine residue present in KSTa-1 promises to be useful as a reactive amino acid that is readily derivatized to allow coupling of the enterotoxin to supports for affinity chromatography and antigenic conjugates. Additionally, the insertion of the lysine residue carboxy terminal to the Ser-Thr sequence adds a reversible “handle” to the toxin sequence in that the Ser-Thr-Lys segment can be removed by treatment with trypsin, releasing the native form of STa.     

Spatial and temporal patterns of intracellular calcium in colonic smooth muscle

Summary Intracellular calcium [Ca²⁺] _i measurements in cell suspension of gastrointestinal myocytes have suggested a single [Ca²⁺] _i transient followed by a steady-state increase as the characteristic [Ca²⁺] _i response of these cells. In the present study, we used digital video imaging techniques in freshly dispersed myocytes from the rabbit colon, to characterize the spatiotemporal pattern of the [Ca²⁺] _i signal in single cells. The distribution of [Ca²⁺] _i in resting and stimulated cells was nonhomogeneous, with gradients of high [Ca²⁺] _i present in the subplasmalemmal space and in one cell pole. [Ca²⁺] _i gradients within these regions were not constant but showed temporal changes in the form of [Ca²⁺] _i oscillations and spatial changes in the form of [Ca²⁺] _i waves. [Ca²⁺] _i oscillations in unstimulated cells (n = 60) were independent of extracellular [Ca²⁺] and had a mean frequency of 12.6 +1.1 oscillations per min. The baseline [Ca²⁺], was 171 ± 13 nm and the mean oscillation amplitude was 194 ± 12 nm. Generation of [Ca²⁺] _i waves was also independent of influx of extracellular Ca²⁺. [Ca²⁺] _i waves originated in one cell pole and were visualized as propagation mostly along the subplasmalemmal space or occasionally throughout the cytoplasm. The mean velocity was 23 +3 m per sec (n = 6). Increases of [Ca²⁺] _i induced by different agonists were encoded into changes of baseline [Ca²⁺] _i and the amplitude of oscillations, but not into their frequency. The observed spatiotemporal pattern of [Ca²⁺] _i regulation may be the underlying mechanism for slow wave generation and propagation in this tissue. These findings are consistent with a [Ca²⁺] _i regulation whereby cell regulators modulate the spatiotemporal pattern of intracellularly generated [Ca²⁺] _i oscillations.The authors thank Debbie Anderson for excellent technical assistance with the electron microscopy and Dr. M. Regoli for providing the NK-1 agonist [Sar⁹,Met(O₂)¹¹]-SP. This work was supported by National Institutes of Health Grants DK 40919 and DK 40675 and Veterans Administration Grant SMI.     

青藏高原东缘的锈菌资料I.竹上的柄锈菌一新种

描述了采自四川西部山区竹上的柄锈菌一新种,即寄生在箭竹Sinarundinaria nitida(Mitf.) Nakai上的箭竹柄锈菌Puccinia sinarundinariae J-y. Zhuang & S.-x. Wei。模式标本保藏在中国科学院微生物研究所真菌标本室。     

不同叶色水稻叶绿体密度及基粒结构的计算机图象分析

水稻叶绿体计算机图象分析表明,随着叶片色级的提高,叶绿体表面积密度、体积密度以及两者的比值都相应增加。深色稻叶基粒堆直径与高度、类囊体垛叠数与类囊体厚度、叶绿素与类胡萝卜素含量、气孔导度与净光合率均大于浅色叶片。深色叶片基粒堆密集,有些基粒类囊体出现沿叶绿体长轴方向排列整齐现象;浅色叶片基粒堆稀疏,其中较大的基粒类囊体与长轴呈倾斜排列。     

青藏高原东缘的锈菌资料Ⅱ.裸堆串孢锈菌属在我国的首次记录

裸堆串孢锈菌属以冬孢子单孢串生为主要特征,孢子堆裸露缺包被,外观酷似柄锈属的孢子堆。此属已知7种。寄生于菊科,大戟科和荨麻科植物,6种分布美洲,1种分布东亚.本文报告亚洲仅知的一种,即寄生于宽叶孢麻Urtica laetevirens Maxim.的川息尔堆串孢锈菌Baeodromus tranzschelii Azbukina,标本采自四川九寨沟(岷山).     

淡色库蚊对敌百虫的抗药性研究——抗性谱及联合作用

1973年采集于上海闸北区的淡色库蚊幼虫在室内以敌百虫选育抗性品系(RD品系)获得成功,F₁₂代的LC₅₀已为室内正常品系(SEN)的240多倍。RD品系的抗性谱表明,对有机磷杀虫剂均具有不同程度的交互抗性;对有机氯如DDT、丙体666和氨基甲酸酯类等杀虫剂无明显的交互抗性;对天然除虫菊和拟除虫菊酯类有低度的负交互抗性。并测定了29种药剂与敌百虫混用对RD品系和SEN品系的增效作用。还测定了对敌百虫有较高交互抗性的杀虫剂分别与TPP,TOCP、稻瘟净、异稻瘟净和增效醚混用后的增效作用。     

Ginsenoside Rg1 protects H9c2 cells against nutritional stress-induced injury via aldolase /AMPK/PINK1 signalling

Insufficient nutrients supply will greatly affect the function of cardiac myocytes. The adaptive responses of cardiac myocytes to nutritional stress are not fully known. Ginsenoside Rg1 is one of the most pharmacologically active components in Panax Ginseng and possesses protective effects on cardiomyocyte. Here, we investigate the effects of ginsenoside Rg1 on H9c2 cells which were subjected to nutritional stress. Nutritional stress-induced by glucose deprivation strongly induced cell death and this response was inhibited by ginsenoside Rg1. Importantly, glucose deprivation decreased intracellular ATP levels and mitochondrial membrane potential. Ginsenoside Rg1 rescued ATP levels and mitochondrial membrane potential in nutrient-starved cells. For molecular mechanisms, ginsenoside Rg1 increased the expressions of PTEN-induced kinase 1 (PINK1) and p-AMPK in glucose deprivation treated H9c2 cells. Reducing the expression of aldolase in H9c2 cells inhibited ginsenoside Rg1′s actions on PINK1 and p-AMPK. Further, the nutritional stress mice were used to verify the mechanisms obtained in vitro. Ginsenoside Rg1 increased the expressions of aldolase, p-AMPK, and PINK1 in starved mice heart. Taken together, our results reveal that ginsenoside Rg1 limits nutritional stress-induced H9c2 cells injury by regulating the aldolase /AMP-activated protein kinase/PINK1 pathway.     

叶表面角质层在贝母属植物叶鉴定中的意义

叶表面角质层在贝母属植物叶鉴定中的意义李萍，濮祖茂，蒋鑫，刘惠娟，徐国钧（中国药科大学生药学教研室；分析中心电镜室南京２１０００９）ＴｈｅｄｉａｇｎｏｓｔｉｃｖａｌｕｅｏｆｔｈｅｃｕｔｉｃｌｅｉｎｔｈｅｌｅａｖｅｓｆｒｏｍｇｅｎｕｓＦｒｉｔｉｌｌａｒ...