地统计学方法在长白落叶松人工林凋落物现存量估测中的应用

采用地统计学的变异函数分析方法定量研究了15年生落叶松(Larix olgensis)人工纯林凋落物层重量的空间异质性特征,利用地统计学的克里格内插法结合定积分,对凋落物层的重量进行了估测.结果表明1)不同分解层次的凋落物重量的变异函数曲线理论模型均为球状模型,空间变异主要是由结构性因素引起,且空间自相关程度均属中等以上(空间结构比＞25%).2)非参数统计的成对样本符号检验结果表明,变异函数分析结果基础上的克里格内插法适用于凋落物重量的估计.利用此估计值,拟合其与位置坐标值之间的多元回归关系均为二元十次余弦级数多项式.利用此多项式,通过定积分的方法(积分区间为整块样地的大小),估计出15年生落叶松人工纯林中凋落物层的未分解、半分解、完全分解和腐殖质层的重量分别为4.7753、5.4129、8.0742、10.9269t hm-2.3)采用地统计学的克里格空间插值,结合多元回归和定积分的方法,可以实现落叶松人工林凋落物层重量的准确估计.     

Biosynthetic pathways of the pheromone of the Egyptian armyworm Spodoptera littoralis

Abstract Most insect pheromones comprise multicomponent blends of geometric or optical isomers, and one major question is how insects produce species‐specific ratios of components for successful reproductive isolation. Key enzymes suggested to be involved in pheromone biosynthesis are acetyl‐coenzyme A carboxylase and fatty acyl synthetase, chain‐shortening enzymes, desaturases, elongases, reductases, oxidases, and alcohol acetyl transferases. The female pheromone composition of the Egyptian armyworm Spodoptera littoralis (Boisd.) is highly dependent on the origin of the strain. In this review, we present a summary of the different reported pheromone compositions of the moth, including from our recent studies on this subject, as well as the biosynthetic routes to the different components and the molecular approaches involved. In addition, the key role played in the proposed biosynthetic pathways by a number of important biosynthetic enzymes, such as chain shortening enzymes, desaturases and alcohol acetyl transferases, is outlined, as well as the latest developments on the inhibition of these enzymes.     

Hydrophobicity and surface electrostatic charge of conidia of the mycoparasitic <Emphasis Type="Italic">Trichoderma</Emphasis> species

The present investigation was done to understand the fungal-fungal interactions mechanisms based on level of nonspecific adhesion of a potential fungal mycoparasite (Trichoderma) to their fungal host (Macrophomina phaseolina). The relative cell surface hydrophobicity (CSH) and cell surface electrostatic charge (CSEC) of 29 isolates of Trichoderma species, analyzed by bacterial adhesion to hydrocarbon (BATH), hydrophobic interaction chromatography (HIC), microelectrophoresis and contact angle, revealed a large degree of variability. CSH and CSEC of conidia depended on culture age, pH and temperature. Maximum CSH and CSEC were recorded in 25–28 °C range, and both declined significantly with increasing temperature. Isolate Trichoderma hazianum (Th)-23/98 expressed surface hydrophobicity at 25–28 °C and hydrophilicity at 40 °C. Surface hydrophobicity of the isolate was susceptible to various proteases (trypsin, pepsin, proteinase k and a-chymotrypsin) and inhibitors (SDS, mercaptoethanol and Triton X-100) and a significant reduction in CSH was recorded in hydrophobic conidia. Hydrophilic conidia remained more or less unaffected by such treatments. SDS-PAGE analysis of the hydrophobic and hydrophilic conidia exhibited several protein bands in the 25 to 61 kDa range. However, each protein population contained one protein that was not observed in the other population. For hydrophobic conidia, the unique protein had an apparent molecular mass of 49 kDa, while the unique protein associated with hydrophilic conidia had a molecular mass of 61 kDa. Our findings suggest that CSH and CSEC of mycoparasitic Trichoderma may contribute to non-specific adhesion on to the sclerotial surfaces of Macrophomina phaseolina that may be influenced by growth and environmental conditions.     

近海生态系统健康状况评价的研究进展

在可持续发展观的推动下,水域生态系统健康问题已引起各界的广泛重视.其中,河流、湖泊等水域的健康评价已开展很多,但对近海生态系统健康的研究还处于探讨阶段.本文在调研国内外大量文献的基础上,对近海生态系统健康的概念进行辨析,总结了近海生态系统健康状况评价的方法、指标筛选原则和研究思路等,并系统地列举了近海生态系统状况健康评价的一些相关量化指标.最后,针对目前近海生态系统健康研究领域存在的主要问题,提出了近海生态系统健康研究的发展方向,认为今后开展近海生态系统健康状况评价研究还需在概念及内涵剖析、评价指标筛选、评价尺度选取和评价方法集成等方面进一步加强.     

徐闻西岸造礁石珊瑚的组成及空间分布

2008年5-6月在徐闻西岸设置了25个站点,运用截线样带法调查了造礁石珊瑚的种类多样性和空间分布.本次研究共发现造礁石珊瑚57种,每个站位的种类数均不超过30种.Shannon-Wiener多样性指数和Pielou均匀度指数均值分别为1.79和0.42.二异角孔珊瑚(Goniopora duofasciata)、盾形...     

Protein dynamics during seed germination under copper stress in Arabidopsis over-expressing <Emphasis Type="Italic">Potentilla superoxide dismutase</Emphasis>

Copper (Cu), though an essential micronutrient for plants, poses toxicity at higher concentrations possibly by inducing oxidative stress. With the background that enzyme superoxide dismutase (SOD) ameliorates oxidative stress, the present work focused on understanding physiological and proteomic response of Arabidopsis seeds constitutively over-expressing copper–zinc SOD of Potentilla atrosanguinea (PaSOD) during germination in response to varied concentrations of copper sulphate (Cu stress). Transgenics showed higher germination percentage and required less “mean time to germination” under Cu-stress. In response to Cu stress, 39 differentially expressed protein spots were detected by 2-D electrophoresis in proteins of germinating wild type (WT) and transgenic seeds, of which 14 spots appeared exclusively in transgenics. Among the rest 25 protein spots, 14 showed down-regulation, one showed up-regulation, and 10 spots disappeared. MALDI-TOF and subsequent peptide mass fingerprinting analysis revealed that the down-regulated proteins in transgenics were related to oxidative stress, detoxification, germination, intermediary metabolism and regulatory proteins. Up-regulated proteins in WT and down-regulated proteins in transgenic during Cu stress were the same. Changes in key proteins, vis-à-vis alleviation of oxidative stress in transgenic Arabidopsis over-expressing PaSOD possibly alleviated toxicity of Cu-induced stress during seed germination, resulting in higher germination rate and germination percentage.     

Halobacterium salinarum storage and rehydration after spray drying and optimization of the processes for preservation of carotenoids

Extremophiles - Spray drying is appropriate for the preservation of halophilic microorganisms due to the nature of these microorganisms, as they survive in adverse environmental conditions by being...     

禁食和重喂食对大绒鼠体重、产热和血清瘦素的影响

动物行为和生理活动的适应性调节是应对食物资源变化的主要策略。为探讨禁食和重喂食对大绒鼠体重、产热和血清瘦素的影响,测定了禁食和重喂食条件下大绒鼠的体重、体脂重量、静止代谢率、身体组成、血清瘦素含量以及禁食后重喂食期间的摄食量。结果显示:禁食导致大绒鼠体重、体脂重量和静止代谢率显著下降,重喂食后体重和静止代谢率能够恢复到对照组水平,而体脂重量却不能恢复。禁食12 h 后血清瘦素含量快速下降,重喂食后未能恢复到对照水平。此外,大绒鼠在禁食后重喂食期间摄食量没有补偿性增加,血清瘦素含量与体脂重量呈正相关关系。这些结果很可能反映出大绒鼠能调节自身生理状况以适应短期的能量缺乏,主要通过降低体重、血清瘦素含量和代谢活性器官重量以减少能量消耗。禁食后重喂食时大绒鼠没有摄食过量。血清瘦素的下降早于体重和体脂的下降。     

戊型肝炎病毒实验感染恒河猴的研究

报道了用戊型肝炎(Hepatitis E, HE)病人粪便悬液感染恒河猴后的组织病理学、血液生化与免疫学以及病毒学分子生物学检测的结果.三只实验猴在感染后第3～4周均出现ALT异常;粪便以及肝脏与胆囊组织超薄切片中电镜观察到27～34nm大小的病毒样颗粒;病理组织切片观察表明,肝脏组织有典型的急性炎症病灶;粪便与血清经RT-nPCR扩增到戊型肝炎病毒(Hepatitis E Virus, HEV)特异性片段,粪便排毒从感染后第7天持续至第50天左右,病毒血症迟于粪便排毒,出现于感染后两周左右,维持1～2周;ELISA检测发现,实验猴血清中HEV IgG抗体水平在感染后3～4周阳转,4～5个月后转阴.这些实验结果提示,恒河猴作为HEV感染实验动物模型是理想的,建立系统的恒河猴实验模型对探讨HEV感染发病机理、机体免疫应答以及临床诊断与疫苗研制具有重要意义.     

Genome wide survey of G protein-coupled receptors in <Emphasis Type="Italic">Tetraodon nigroviridis</Emphasis>

Background  

The G-protein-coupled receptors (GPCRs) constitute one of the largest and most ancient superfamilies of membrane proteins. They play a central role in physiological processes affecting almost all aspects of the life cycle of an organism. Availability of the complete sets of putative members of a family from diverse species provides the basis for cross genome comparative studies.