Timing and plasticity of shoaling behaviour in the zebrafish, Danio rerio

The zebrafish has become a major model system for biomedical research and is an emerging model for the study of behaviour. While adult zebrafish express a visually mediated shoaling preference, the onset of shoaling behaviour and of this preference is unknown. To assess the onset of these behaviours, we first manipulated the early social environment of larval zebrafish subjects, giving them three model shoaling partners of the same pigment phenotype. We then assayed the subjects' preferences using binary preference tests in which we presented subjects with two shoals, one shoal of fish exhibiting the same pigment pattern phenotype as their models and another shoal with a radically different pigment pattern. To determine whether or not the visually mediated preference could be altered once it was established, we further manipulated the social environment of a number of subjects, rearing them with one model shoal and testing them, then changing their social consorts and retesting them. Our results demonstrate that larval zebrafish shoal early in their development, but do not exhibit a shoaling preference until they are juveniles. Moreover, we find that the shoaling preference is stable, as changing the social environment of fish after they had acquired a preference did not change their preference. These data will facilitate investigations into the mechanisms underlying social behaviour in this vertebrate model system.     

芒蛱蝶西藏一个新纪录及川藏地区黄缘蛱蝶的历史记录

在2017年6-7月对藏东南地区蝶类资源进行调查时,于墨脱县采集到了2枚芒蛱蝶Euripusnyctelius(鳞翅目:蛱蝶科)标本,经鉴定为西藏新纪种,同时也是首次在西藏发现芒蛱蝶属;于察隅县采集到1枚黄缘蛱蝶Nymphalisantiopa(鳞翅目:蛱蝶科),兹此列举诸多川藏地区黄缘蛱蝶的历史采集记录;并结合西藏处于古北区和东洋区生物交界带的地理位置,对在西藏发现两种蝴蝶的特殊意义进行了简要讨论。     

A novel gene delivery system targeting cells expressing VEGF receptors

Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors.GV1,GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex.Using pSV2-β-galactosidase as a reporter gene,it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) and human malignant melanoma cell lines (A375) in vitro.In vivo experiments,exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO,human malignant melanoma A375 and human hepatoma graft in nude mice.This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice.These results are correlated with the relevant receptors(flt-1,flk-1/KDR) expression on the targeted cells and tissues.     

费氏链霉菌中子辐射诱变菌株对新霉素的生物转化

对新霉素产生菌费氏链霉菌进行中子辐射诱变和突变株筛选, 获得不产新霉素的突变株。以突变株为转化菌种, 以新霉素为底物, 对转化发酵液进行高效液相色谱分析, 研究了不同转化条件对新霉素转化的影响。结果表明, 底物浓度、底物添加时间、底物添加方式、接种量、培养基装量、转化时间、碳源、氮源、pH、温度对新霉素转化具有不同程度的影响。以转化条件优化参数进行转化大量培养, 转化液经4步离子交换层析进行分离纯化, 薄层层析检测纯化样品为单一斑点。采用薄层生物自显影对获得的4个转化产物分离样品做生物活性检测, 发现4个样品对金黄色葡萄球菌和姜青枯假单孢杆菌都具有抑制活性, 1个样品对大白菜软腐样品具有明显的抑制活性。     

河西走廊春季不同盐碱土壤中微生物数量、酶活性与理化因子的关系

[目的]揭示盐碱土壤微生物量与土壤因子间的关系.[方法]选择河西走廊不同盐碱程度的11个样点在春季进行采样,研究了土壤的微生物数量、酶活和理化性质,并对其进行方差分析、简单相关分析、逐步回归分析和主成分分析.[结果]河西地区原生盐碱地、次生盐碱地与农田土在土壤理化性质和土壤微生物数量等方面均有差异;河西地区土壤较贫瘠,土壤微生物数量较低,且分布有规律性,即原生盐碱土＜次生盐碱土＜农田土;放线菌、真菌、碱性磷酸酶、脲酶和有效磷5个因子是引起土壤微生物数量、酶活性与理化因子之间相关性的主要因素.[结论]结果证实河西地区盐碱土壤中磷的循环很大程度上影响着土壤微生物数量.     

米槠-木荷林优势种群的年龄结构及其更新策略

通过年轮分析,构建了浙江天童米槠-木荷林优势种木荷、米槠、石栎的年龄结构,分析了高生长和径向生长及萌枝策略随年龄的变化规律,探讨了干扰对群落动态的影响。研究结果表明:(1)3个物种的胸径、高度与年龄的关系均可用logistic曲线和线性模型拟合,但随年龄增加胸径、高度与年龄的关系显著下降。(2)随年龄增加3树种的DBH/H逐渐增加,米槠、石栎幼龄个体(1-20a)的有萌个体率和有萌个体萌枝数逐渐下降;米槠和石栎幼苗的主干较木荷细长、多萌枝,木荷和石栎成树主干较米槠细长;体现了米槠的更新策略具开拓性,木荷的具保守性,石栎在幼龄期具开拓性,成年期转为保守性。(3)米槠和石栎的年龄结构呈逆J型,幼龄个体充足,但中龄段(21-40a)存在更新断层,这与其高消耗的开拓性策略有关;木荷的年龄结构呈间歇型,各龄级均存有个体,这与其保守性策略有关;(4)3物种在大龄级上(52-60a)均存在更新高峰,与该地区的择伐干扰时间一致,高强度的干扰促生了次生演替,形成了以木荷为第一优势种的群落。(5)米槠、木荷、石栎的年龄结构是更新策略和干扰的综合表现,它不仅与径级结构一样可展现种群更新特征、预测种群发展动态,更能精确地反映群落动态事件的发生频次和发生时间。     

上海四种常见树种单株固碳能力差异及其影响因子

城市树木的固碳能力是决定城市绿地碳汇大小的重要因素。为探究上海常见树种单株固碳能力的差异及影响因子,使用174个城市森林固定样地的长期观测数据,估算了香樟、水杉、银杏和雪松四个树种的单株固碳能力(即年固碳量),采用多元线性回归模型分析了各树种单株固碳能力与个体大小、植株密度和城市环境因子(温度、降水量和夜间灯光强度)的关系。结果表明:(1)香樟、水杉、银杏和雪松的单株固碳能力分别介于4.01-51.58 kg/a、1.04-13.47 kg/a、0.62-18.56 kg/a和1.48-8.47 kg/a之间,在各径组中香樟的固碳能力均显著高于其他树种。(2)个体大小是决定单株固碳能力的最主要因子,个体越大(胸径0-50 cm范围内)单株固碳能力越大;植株密度越大,香樟和水杉的单株固碳能力越小,银杏的单株固碳能力越大。(3)城市环境因子中,温度对树木单株固碳能力有显著负向影响,而降水量和夜间灯光强度对树木单株固碳能力的影响因树种而异。其中香樟和水杉分别与降水量呈显著负相关和正相关关系,但均与夜间灯光强度呈显著正相关关系。在上海未来城市森林建设和管理中,应根据不同树种单株固碳能力的差异及其对不同环境因子的敏感性,适地适树绿化造林,提升城市森林的固碳效益。