Vomifoliol 9-O-α-arabinofuranosyl (1→6)-β-d-glucopyranoside from the leaves of Diospyros Kaki stimulates the glucose uptake in HepG2 and 3T3-L1 cells

A novel α-glucosidase inhibitor, vomifoliol 9-O-α-arabinofuranosyl (1→6)-β-d-glucopyranoside, was isolated for the first time from leaves of Diospyros Kaki and its bioactivity analyzed. This inhibitor exhibited strong anti-α-glucosidase activity with an IC₅₀ value of 170.62 nM and stimulated a dose-dependent increase in the uptake of a fluorescent d-glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG), in HepG2 cells at a rate higher than that of insulin controls. It was also found to be associated with adipocyte differentiation and moderate increases in 2-NBDG uptake by 3T3-L1 cells. These findings suggest that vomifoliol 9-O-α-arabinofuranosyl (1→6)-β-d-glucopyranoside could augment peripheral glucose as an insulin-sensitizing agent against Type 2 diabetes mellitus.     

河南省金岗台自然保护区两栖动物资源及保护

1999年4月～2009年9月,运用样带法、编目法和访问调查等方法对河南省金岗台自然保护区的两栖动物资源状况进行为期10年的调查.结果显示,金岗台自然保护区现有两栖动物21种,隶属于2目8科16属;区系成分以东洋界为主,兼有古北界和广布种,体现了保护区地理过渡带和气候过渡带的特点.金岗台自然保护区面积狭小,不能满足现有两栖类生态和繁殖所需要的空间和资源,有必要提升保护区级别,扩大保护区面积.     

SCGE法检测敌敌畏对大鳞副泥鳅DNA损伤的研究

目的 采用SCGE技术检测敌敌畏对大鳞副泥鳅DNA的损伤效应.方法 设置敌敌畏0.64 μg/L、1.28μg./L、1.92μg/L、2.56μg/L、3.20μg/L 5个浓度组和一个空白对照组(15尾大鳞副泥鳅/组),通过单细胞凝胶电泳技术(scGE)研究各浓度敌敌畏处理组在分别处理l d、2 d、3 d后对大鳞...     

日本三角涡虫神经系统的组织学观察

为了给涡虫神经生物学的比较研究提供基础资料和通过RNAi技术为研究与脑部再生有关基因的功能奠定基础,本研究使用石蜡连续切片技术,经HE和Masson染色后,对日本三角涡虫Dugesia japonica的神经系统进行观察.日本三角涡虫的中枢神经系统由脑和2条纵神经索组成,脑呈马蹄形;纵神经索从头部到尾部逐渐变细;脑部神经细胞突起连接成网状,纵神经索内神经细胞突起呈纵向排列;咽壁神经组织排列成内外2个圆筒状.这些结构差异反映出日本三角涡虫在涡虫纲系统演化中处于较高级的地位.     

Fertile sediment and ammonium enrichment decrease the growth and biomechanical strength of submersed macrophyte Myriophyllum spicatum in an experiment

Decline of submersed macrophytes has occurred in eutrophic lakes worldwide. Little is known about effects of nutrient enrichment on biomechanical properties of submersed macrophytes. In a 30-day experiment, Myriophyllum spicatum was cultured in aquaria containing two types of sediment (mesotrophic clay vs. fertile loam) with contrasting water NH₄ ⁺ concentrations (0 vs. 3.0 mg L^?1 NH₄–N). The plant growth, shoot and root morphology, stem biomechanical properties, and stem total nonstructure carbohydrates content (TNC) were examined. The NH₄ ⁺-enriched water, particularly combined with the fertile sediment, caused adverse effects on M. spicatum as indicated by reductions in the growth, stem biomechanical properties (tensile force, bending force and structural stiffness), and TNC content. These results indicate that increased sediment fertility and water NH₄ ⁺-enrichment made the plant more fragile and vulnerable to hydraulic damage, particularly for the upper stem, implying that M. spicatum was prone to uprooting and fracture by hydraulic force, and the broken fragment from parent shoot of M. spicatum might have low-survival potential due to its low-TNC content. This may be a mechanical aspect for the decline of submersed macrophytes and makes it more difficult to restore submersed vegetation in the eutrophic lakes.     

Seed predation patterns favor the regeneration of dominant species in forest gaps compared with the understory in an oak-pine mixed forest

Recent studies have demonstrated the higher likelihood of regeneration in forest gaps compared with the understory for the dominant species in pine-oak mixed forest. Here, we tested whether rodent seed predation or dispersal was beneficial for gap regeneration. We tracked the seed predation and dispersal of Quercus aliena var. acuteserrata and Pinus armandii using coded plastic tags in the forest understory close to gaps. Our results demonstrated that the proportions of initial buried seeds of both species were significantly more abundant in the forest understory compared with gaps. After seed caching, however, significantly lower proportions of the seeds of both species survived in the forest understory compared with gaps during the 30-day observation period. The final survival proportions of the seeds cached in the forest understory were lower than those cached in the gaps the next spring, which indicated that small rodents rarely retrieved scatter-hoarded seeds from forest gaps. Our findings suggest that rodent seed predation patterns contribute to the regeneration of the dominant species in gaps compared with the understory in a pine-oak mixed forest. In the study area, reforestation usually involves planting seedlings but direct sowing in forest gaps may be an alternative means of accelerating forest recovery and successional processes.     

Plant genetic diversity and grazing management on the Qinghai-Tibetan Plateau: A case study of a dominant native wheatgrass (Elymus nutans)

Grazing management on the Qinghai-Tibetan Plateau in China concerns farmers, scientists and policy makers because of its geographical uniqueness. To investigate the effects of grazing on genetic diversity in native plants, the dominant perennial wheatgrass Elymus nutans was used as a model to examine genetic diversity and spatial population structure under different grazing intensities. Intra-population genetic diversity in three grazed areas was higher than un-grazed area; however, the genetic diversity decreased with increasing grazing intensity. Genotypes from four areas were separated into two groups (grazed and un-grazed) through a clustering analysis. Approximately 12% (G_st = 0.1487) of the DNA variation was apportioned among populations by AMOVA indicating a relatively low degree of inter-population genetic differentiation. Significant spatial auto-correlations and subpopulation structure were also observed within the four areas, and the genetic ‘patch’ size decreased with increasing grazing intensity. On the high and cold Qinghai-Tibetan Plateau, grazing is suitable for the maintenance of genetic diversity, and a light grazing intensity is optimal for the conservation of perennial grass germplasm and long-term grassland management.     

Characteristic of PGDS potential regulation role on spermatogenesis in the Chinese mitten crab Eriocheir sinensis

Prostaglandin D synthase (PGDS) catalyzes the isomerization of PGH2 to produce PGD2 in the presence of sulfhydryl compounds. In this study, a full length PGDS gene comprising 1250 nucleotides from the Chinese mitten crab Eriocheir sinensis (Es-PGDS) was characterized, with a 615 bp open reading frame encoding 204 amino acid residues. Its deduced peptide has high homology with other species' PGDS protein. The Es-PGDS mRNA expression was tissue-related, with the highest expression observed in the hepatopancreas, accessory sex gland, testis and ovaries. We also detected the different stages of tissue expression and the enzyme activity for Es-PGDS in the testis and male crab hepatopancreas. The different expression patterns and its corresponding enzyme activity level indicated that PGDS is involving in the regulation of reproductive action during the period of rapid development in E. sinensis. Furthermore our research could arouse a heat debate on the PGDS reproductive function in invertebrate and further study will be needed to determine the molecular mechanism(s) linking PGDS functions to spermatogenesis and ontogenesis if this gene is to be exploited as a molecular biomarker in further studies of development.