Comparative Analysis of Bacillus thuringiensis Vip3Aa57 and Vip3Aa62 Insecticidal Activities

Bacillus thuringiensis (Bt) exhibits strong insecticidal activity and is harmless to non-target organisms such as human and animals. Bt becomes the most commonly used environment-friendly insecticidal microorganism. However, the insecticidal activities of different Bt strains variy significantly. Therefore, it is particularly important to compare the insecticidal activities of different strains and explore their insecticidal effector mechanisms to expand Bt insecticidal spectrum and enrich transgenic resources. Here, the insecticidal activities of Vip3Aa57 and Vip3Aa62 strains, carrying vegetative insecticidal protein-encoding genes that were inserted into the expression vector pET-21b and transformed into Escherichia coli Rosetta (DE3) strain, expressing 88 ku protein, were compared. Vip3Aa57 protein reportedly displayed body weight inhibition effect on Spodoptera exigua without affecting Heliothis armigera while Vip3Aa62 protein was known to have strong insecticidal activity against S. exigua (LC50=5.124 ng ? mg-1). A low H. armigera activity (LC50=870.1 ng ? mg-1) was observed. The paraffin sectioning results showed that Vip3Aa57 protein affected S. exigua midgut cell morphology. The laser confocal microscopic imaging results showed that Vip3Aa57 bound to receptors in the midgut without damaging the midgut tissue morphology. This study would be conducive for making full use of Bt strains in the soil to compare the insecticidal activities of different Vip insecticidal genes. It could thus provide significant help in revealing the underlying insecticidal mechanisms of Vip3Aa insecticidal genes, developing new insecticidal proteins and delaying pest resistance problems.     

玄武岩纤维-砒砂岩水泥土力学特性试验研究

为了降低黄河流域泥沙治理成本,提高砒砂岩的利用价值,在砒砂岩中掺入适量水泥和纤维改善其力学性质及功能性.借助玄武岩纤维(BF)的加筋效应,配制玄武岩纤维掺量为0.2%,0.5%,0.7%的BF-砒砂岩水泥土试块,进行无侧限抗压强度和SEM扫描电镜试验.探究BF掺量、龄期对BF-砒砂岩水泥土强度影响以及BF-砒砂岩水泥土强度形成机理; 建立了玄武岩纤维参与下砒砂岩水泥土应力-应变曲线方程.结果表明:纤维掺入有效提高了砒砂岩水泥土的强度,其强度随玄武岩纤维掺量的增加呈先增大后减小的趋势,掺量为0.2%时达到峰值强度; BF-砒砂岩水泥土后期强度同比砒砂岩水泥土强度提高更明显; BF-砒砂岩水泥土的龄期与无侧限抗压强度表现为正相关,而与其强度增长速率表现为负相关; 水泥掺量10%、纤维掺量0.2%的砒砂岩水泥土在强度指标上完全可以替代水泥掺量15%的砒砂岩水泥土; 建立龄期28 d时,BF掺量0~0.7%的BF-砒砂岩水泥土应力-应变曲线方程,反映了各纤维掺量下应力-应变变化及破坏情况.     

荔枝小孢子发生和雄配子体的形成

应用光学显微镜和扫描电镜技术,观察了荔枝小孢子发生和雄配子体的形成,结果如下:花药四室,花药壁由5层细胞组成,小孢子四分体为四面体型,小孢子母细胞胞质分裂为同时型。具腺质绒毡层。成熟花粉为两细胞型。花粉粒扁球形,极面观呈钝三角形,赤道面观为椭圆形,具三沟孔。花粉壁务内外两层,表面具条纹状纹饰。花粉粒发育过程中,常出现退化现象,在低产的植株中尤为明显。     

海南普通野生稻的花粉育性观察及杂交亲和性

对海南3个不同居群的普通野生稻(O.rufipogon Griff.)的花粉育性进行了观察研究,并采用荧光显微镜技术观察了转基因水稻花粉在不同居群的普通野生稻柱头上的萌发和在花柱内的生长过程。结果表明,以转基因水稻为对照,3个不同居群的野生稻相互之间花粉可育率在1%水平上差异极显著。用荧光显微镜观察时发现,转基因水稻花粉能在3个居群的普通野生稻的柱头上萌发并能到达胚珠,二者杂交亲和,同时发现,花粉管进入三亚居群胚珠的数目比儋州、万宁居群的数目多,说明相对于儋州、万宁居群来说,三亚居群与转基因水稻的杂交亲和性更高。     

细薄星芒海绵体内微生物分布特点的透射电子显微镜观察与分析

采用透射电子显微镜对我国南海细薄星芒海绵体内微生物的分布进行了观察研究，同时结合海绵的结构特点与摄取营养的方式对分布特点进行了分析讨论。研究证明：在细薄星芒海绵体内除骨骼外的细胞间中质层、细胞内、海绵内腔等部位均分布着形态多样的微生物，其中海绵中质层是共(寄)生微生物最为丰富的地方。海绵微生物的分布特点与海绵腔状多孔的结构以及依靠过滤海水获取营养的方式有关，这对于将来揭示微生物在海绵体内的聚集机制及其与环境的关系具有重要价值。     

赤眼鳟精子入卵的扫描电镜观察

选取性成熟的赤眼鳟（Squaliobarbus curriculus）亲鱼，体质量800～2300g，经人工催产后，在27℃条件下进行干法人工授精。取成熟卵及相遇后不同时间段的精卵用扫描电镜对赤眼鳟成熟精、卵及精子入卵早期过程进行观察。结果显示，赤眼鳟成熟精子为鞭毛型形态，全长19．6～22．4μm。头部直径约1.65μm，鞭毛长17．8～20．6μm头径与鞭毛长度之比为（1：9．89）～（1：11．4）。赤眼鳟成熟卵呈圆形，具单一受精孔。卵膜厚度约为2.78μm，卵膜表面平滑光洁；无明显的沟或嵴，卵膜表面可见均匀分布有很多孔小管，直径约0.14μm。在动物极具一漏斗状凹陷卵膜孔，直径12．46～14．10μm，其底部为圆环状的受精孔，受精孔的周边平滑，向四周呈辐射状隆起，外孔径约5．21μm，内孔径约2．71μm。在27℃时，赤眼鳟精子18s内可完成入卵过程；约60s后受精孔外的精子全部解体。通过对精子、卵及精孔管的测量和扫描电镜观察，确定赤眼鳟受精方式为单精受精。     

Developmental changes in structure and polypeptide profile of the androgenic gland of the freshwater prawn Macrobrachium rosenbergii

Although the mechanism of sex-differentiation in crustaceans has yet to be defined, the androgenic gland (AG) is thought to be the exclusive organ that produces the androgenic hormone (AH) which induces male sexual development. This paper presents results of light and transmission electron microscopy and total protein analysis of androgenic glands from three male morphotypes (orange-claw, orange-blue-claw and blue-claw) of the freshwater prawn, Macrobrachium rosenbergii. Highest protein content (76 µg//AG) was found in the blue-claw morphotype as compared to the orange-blue-claw (45 µg/AG) and the orange-claw morphotype (19 µg/AG). Sodiumdodecyl sulfate polyacrylamide gel electrophoresis (SDS-page) analysis of the cell free extract of the AG from the three morphotypes revealed four polypeptides (16, 18, 23 and 26 Kd) which quantitatively increase from the sexually immature orange-claw to the sexually mature blue-claw morphotype. The 16 and 18 Kd polypeptides could be the AHs.     

Social organisation, shoal structure and information transfer

Recent work suggests that the social structure of fish shoals is nonrandom with strong tendencies for self‐sorting by phenotype in individuals of several species. The frequency of shoal encounters is high in most freshwater species but lower in pelagic fishes where intershoal distances tend to be greater. Detailed knowledge of the encounter rates between shoals and the exchange rates of individuals between shoals during encounters makes it possible to predict the transmission of learned behaviours through a population.     

Neuronal nitric oxide synthase immunoreactivity in forebrain,pineal, and pituitary of <Emphasis Type="Italic">Oreochromis mossambicus</Emphasis> (Tilapia)

Ultrastructural localization of neuronal nitric oxide synthase (nNOS) in olfactory receptor neurons (ORNs) and immunohistochemical detection of the enzyme in forebrain, pituitary, and pineal were undertaken in the teleost Oreochromis mossambicus. Application of post-embedding immunoelectron microscopy revealed nNOS-labeled gold particles on the cilia, microvilli, mitochondria, and Golgi complex of the ORNs. Gold particles were also seen adhered to microtubules in the axons that extend to the olfactory nerve layer in the olfactory bulb. With light microscopy, nNOS-immunoreactive neurons were seen in preoptic area, nucleus entopeduncularis, and parvocellular, and magnocellular subdivisions of nucleus preopticus (NPO). Numerous cerebrospinal fluid-contacting cells lining the wall of the third ventricle at the level of the NPO showed intense immunoreactivity. Intense to moderate immunoreactivity was observed in the neurons of suprachiasmatic nucleus, nucleus lateralis tuberis pars lateralis, and nucleus recessus lateralis. While several immunoreactive fibers were detected in medial olfactory tract, suprachiasmatic area, and hypothalamo-hypophyseal tract, a few were seen throughout the telencephalon, in the optic chiasma, tuberal area, and inferior lobes. In the pituitary, nNOS-containing fibers were seen in the neurohypophysis, rostral pars distalis, proximal pars distalis, and pars intermedia. While intense immunoreactivity was noticed in some cells in the pineal, immunoreactive fibers were detected in the pineal stalk as well as parenchyma. We suggest that nitric oxide may play a role in processing olfactory and photic information, circadian rhythms, and neuroendocrine regulation in tilapia.