伊洛河流域草本植物群落物种多样性

生物多样性沿环境梯度的变化是生物多样性研究的重要内容,环境梯度包含了多种环境因子(海拔高度、水热条件、人类扰动等)的综合。以伊洛河流域草本植物群落为对象,沿河从入黄河口到河源地选取典型样地调查研究伊洛河流域草本植物群落物种多样性及其分布格局。结果表明:物种丰富度和Shannon-Wiener多样性指数沿河均稍呈"S"型曲线变化,不同群落类型中分布格局差别不大,各群落类型中的物种丰富度和多样性均呈现出中游丘陵山地交界区最高,上游河源区次之,下游平原地区最低的趋势;β多样性指数的变化趋势与α多样性较一致,总体上呈现出中游丘陵山地区物种更替速率较快,平原区更替较慢;在流域内上游河源地属于自然植被区,人为干扰较轻,具有较高的物种多样性,物种替代主要受物种的竞争扩散能力和生境条件的制约;在下游平原农业区,人类活动强烈,区域内以人工生态系统为主,物种组成简单,物种替代具有跳跃性的特征,主要受人类活动的制约;在中游从自然生态系统向农业生态系统的过渡区域,人类活动的扰动有一定的强度,导致该区域内自然分布种和伴人种混合生长,具有较高的物种多样性和较快的物种替代速率。总体上伊洛河流域草本植物群落物种多样性分布格局强烈的受到人类活动的影响,物种替代速率较高。     

脂肪甘油三酯水解酶的研究进展

胰岛素抵抗等代谢疾病的发生与脂代谢紊乱密切相关。细胞中的脂肪主要储存在一个以中性脂为核的细胞器——脂滴(lipid droplet,LD)中。脂肪甘油三酯水解酶(adiposetriglyceride lipase,ATGL)是在脂滴上发现的水解甘油三酯的脂肪酶。除脂肪组织外,ATGL也广泛存在于骨骼肌等多种非脂肪组织中,并发挥着重要的生理功能。越来越多的研究表明,ATGL与中性脂质贮存异常、胰岛素抵抗等代谢疾病密切相关。运动可以通过改变ATGL的表达起到调控脂代谢的作用,进而在防治胰岛素抵抗等代谢疾病中发挥作用。     

有机磷农药的微生物降解研究进展

微生物因种类和代谢多样性在有机磷农药降解中表现出独特的优势。对微生物降解有机磷农药的机制、微生物的获得、基因工程菌的构建及研究展望进行了综述。     

Utilization of Fc receptors as a mucosal vaccine strategy against an intracellular bacterium, Francisella tularensis

Numerous studies have demonstrated that targeting Ag to Fc receptors (FcR) on APCs can enhance humoral and cellular immunity. However, studies are lacking that examine both the use of FcR-targeting in generating immune protection against infectious agents and the use of FcRs in the induction of mucosal immunity. Francisella tularensis is a category A intracellular mucosal pathogen. Thus, intense efforts are underway to develop a vaccine against this organism. We hypothesized that protection against mucosal infection with F. tularensis would be significantly enhanced by targeting inactivated F. tularensis live vaccine strain (iFt) to FcRs at mucosal sites, via intranasal immunization with mAb-iFt complexes. These studies demonstrate for the first time that: 1) FcR-targeted immunogen enhances immunogen-specific IgA production and protection against subsequent infection in an IgA-dependent manner, 2) FcgammaR and neonatal FcR are crucial to this protection, and 3) inactivated F. tularensis, when targeted to FcRs, enhances protection against the highly virulent SchuS4 strain of F. tularensis, a category A biothreat agent. In summary, these studies show for the first time the use of FcRs as a highly effective vaccination strategy against a highly virulent mucosal intracellular pathogen.     

黄河源区玛多县草地退化成因分析

对黄河区玛多县草地退化的自然和人为因素作了深入分析。结果表明,过度放牧是导致玛多县草地退化的主要原因,自20世纪80年代末期以来,玛多县温度和降水较历史平均水平均有较大幅度的提高,其中温度增加表现为明显的暖冬现象,降水增加集中在春夏两季,水热条件的变化是向着利于草地恢复的方向发展的,由于玛多县是一个纯牧业县,扩大畜群数量是经济增长的必然选择,加上人口压力和当地藏族居民的传统价值观,驱使牧畜数量不断扩大,并在70年代末达到最大值,此后长期维持过牧状态,造成草地持续退化,过牧在导致草地退化的同时,也为鼠类的侵入创造了条件,从而加强了退化过程。     

北热带喀斯特森林木本植物花性状及其生境分异

植物花性状的多样化是植物长期进化及自然选择的结果, 不同植物种间花性状的变异与生境存在一定的相关性。北热带喀斯特季节性雨林具有生境异质性强、群落结构复杂、特有成分丰富等特点, 分析该森林植物性状的变化特征及其与生境的关联性, 有助于理解物种共存、协同进化过程和对生境的适应, 可为阐明喀斯特植物的生态适应性、理解生物多样性维持机理提供依据。本研究在弄岗15 ha森林动态监测样地木本植物开花相对集中的时间段进行, 记录并分析了21个物种花性状的变化。根据物种空间分布及其与生境的关联特性, 将21个物种分成偏好谷底、山坡、山顶的3种类型, 分析了这3种类型植物的花性状差异; 另外又根据花性状对21个物种进行聚类分析, 探讨了聚类分组结果和根据偏好生境分组结果的异同。结果表明: 花大小、花色鲜艳度均与物种优势度存在显著的负相关关系, 花小而不鲜艳的物种在群落中更有优势, 表现出更好的适应性; 不同偏好生境的植物花色明度有显著差异, 其他的花性状差异不显著; 聚类分组与根据偏好生境的分组有较好的一致性, 反映出物种的花性状变化响应了生境的变化。综上结果, 我们认为北热带喀斯特季节性雨林植物花性状与物种的优势度及生境条件有密切联系, 在该区域中生境对花性状的影响可能比传粉者更为深刻。     

β‐Cyclodextrin protected Cu nanoclusters as a novel fluorescence sensor for graphene oxide in environmental water samples

This paper proposed a simple and sensitive approach for detecting graphene oxide (GO) in a wide pH range in environmental water samples using fluorescent β‐CD protected Cu NCs based on the hydrogen‐bond interactions between GO and 6‐SH‐β‐CD. The influences of dilution ratio and pH were investigated. We found that the fluorescence quenching efficiency of Cu NCs by GO remained almost the same under pH from 4 to 10, which benefitted the monitoring of GO under different pH conditions in real samples. The fluorescence quenching mechanism was also discussed. The fluorescence of β‐CD protected Cu NCs could be quenched in the presence of GO with a lowest detection concentration of 0.1 mg·L^?1. Good linear correlations were obtained over the concentration range from 0 to 30 mg·L^?1 at different pH values (pH = 4, pH = 7 and pH = 12). In addition, this method was successfully applied to the determination of GO in real samples which presents more opportunities for application in environmental and material sciences.     

Biological effects of amphiphilic copolymer nanoparticle-encapsulated multi-target chemotherapeutic drugs on MCF-7 human breast cancer cells

Introduction

Amphiphilic copolymer nanoparticle-encapsulated multi-target chemotherapeutic drugs have attracted considerable attention due to their favorable drug efficiency and potential application prospect. Studies have shown that an amphiphilic copolymer, methoxypoly(ethylene glycol)-poly(lactide-co-glycolide) modified with ε-polylysine, and encapsulated with hydrophilic doxorubicin, hydrophobic paclitaxel and survivin siRNA profoundly improved the therapeutic effect both in vitro and in vivo.

Objectives

To investigate how MCF-7 cells would response to the exposure of these nanoparticles over with time and assess the biological effects of these nanoparticles and their encapsulated drugs in a holistic manner.

Methods

MCF-7 cells were treated with PBS, nanocarrier and three encapsulated drugs, respectively. Metabolic alterations associated with nano-drugs exposure were investigated by performing untargeted NMR metabolomics with combination of targeted fatty acids analysis by GC-MS on cell extracts. Altered metabolic pathways were further validated by qRT-PCR approach.

Results

Copolymers showed great biocompatibility with cells as it induced transit metabolic disruptions without affecting cell survival rate. The rapid release of encapsulated doxorubicin resulted in inhibition of glycolysis and DNA synthesis, active proteolysis; these metabolic alternations were recovered after 10 h exposure. However, the combination use of multiple drugs consistently induced cell cycle arrest and apoptosis evidenced by reduction in glycolysis, active proteolysis, stimulated O-GlcNAcylation, reduced the PC:GPC ratio and fatty acids accumulation. Prolonged exposure to encapsulated-multiple-drugs also induced oxidative stress to cells.

Conclusion

These findings provide important insight into the biological effects of nanoparticles and their encapsulated drugs while demonstrate that metabolomics is a powerful approach to evaluate the biological effects of nano-drugs.