陆地棉GhSDP1及其启动子的克隆与表达分析

三酰基甘油脂肪酶(SDP1)是催化三酰甘油降解的关键酶,在植物油脂代谢调控中起着重要作用。克隆棉花SDP1并研究其在3种胁迫下的表达分析,为解析棉花SDP1的生物学功能提供依据。以陆地棉品种冀丰1271为试材,克隆GhSDP1编码序列和上游启动子序列;利用PlantCARE分析GhSDP1启动子区顺式作用元件;qRT-PCR检测逆境胁迫下GhSDP1的表达谱;通过烟草瞬时表达pGhSDP1启动子+GUS载体检测启动子活性。结果表明,GhSDP1的编码序列为2 541 bp,其在盐、低温和干旱胁迫下呈差异表达模式。pGhSDP1除具有启动子所必需的TATA-box和CAAT-box等基本顺式作用元件外,还含有多个与光响应、激素响应及逆境应答等相关的顺式作用元件。棉花pGhSDP1启动子能驱动GUS蛋白高效表达,具有较强的启动子活性。研究揭示了棉花GhSDP1参与胁迫应答的新功能。     

A phylogenetic supertree of the bats (Mammalia: Chiroptera)

We present the first estimate of the phylogenetic relationships among all 916 extant and nine recently extinct species of bats Mammalia: Chiroptera), a group that accounts for almost one-quarter of extant mammalian diversity. This phylogeny was derived by combining 105 estimates of bat phylogenetic relationships published since 1970 using the supertree construction technique of Matrix Representation with Parsimony (MRP). Despite the explosive growth in the number of phylogenetic studies of bats since 1990, phylogenetic relationships in the order have been studied non-randomly. For example, over one-third of all bat systematic studies to date have locused on relationships within Phyllostomidae, whereas relationships within clades such as Kerivoulinae and Murinae have never been studied using cladistic methods. Resolution in the supertree similarly differs among clades: overall resolution is poor (46.4%, of a fully bifurcating solution) but reaches 100% in some groups (e.g. relationships within Mormoopidae). The supertree analysis does not support a recent proposal that Microchiroptera is paraphyletic with respect to Megachiroptera, as the majority of source topologies support microbat monophyly. Although it is not a substitute for comprehensive phylogenetic analyses of primary molecular and morphological data, the bat supertree provides a useful tool for future phylogenetic comparative and macroevolutionary studies. Additionally, it identifies clades that have been little studied, highlights groups within which relationships are controversial, and like all phylogenetic studies, provides preliminary hypotheses that can form starting points for future phylogenetic studies of bats.     

凝血瀑布机制的序结构分析方法

凝血系统的瀑布机制揭示了凝血因子间的酶促级联反应过程。在级联反应中,各个因子间明显地存在着序关系,而这种序关系的全体构成了系统的序结构。从系统论的观点看,系统的结构是系统性质与功能的基础,因此,通过模型化方法以及利用凝血因子序结构图建立的序结构分析方法,是分析凝血系统各因子相互作用的有用的工具。对蛋白Ｃ及ＴＦＰＩ进行序结构分析,进一步阐明了这两种抑制剂对外源途径凝血的作用特点。     

Functional constraints on nest characteristics of pebble mounds of breeding male hornyhead chub Nocomis biguttatus

Breeding male hornyhead chub Nocomis biguttatus constructed nests in areas with relatively high but less than maximum flow rate and greater than average water depth. Nests comprised c. 3000 pebbles for a total mass of 11 kg. Males selected pebbles of smaller diameter but higher density than pebbles in the immediate vicinity. Thus, nests balanced the risk of mound erosion and energetic cost of nest construction with the benefits of protection from egg predators and a stable internal flow rate for oxygenation. These data help establish environmental management goals for the conservation of N. biguttatus and the lotic ecosystems dependent upon them.     

SCoT分子标记在植物研究中的应用进展

SCo T是一种新型的目的基因分子标记,该标记不仅能获得与性状联系紧密的目的基因,而且能对性状进行跟踪,已被广泛应用于多种植物的研究。本文概述了SCo T标记的原理、引物设计方法及特点,并从PCR反应体系建立与优化、种质资源遗传多样性与亲缘关系分析、种质鉴定与指纹图谱构建、基因差异表达与分子遗传连锁图谱构建等方面总结了SCo T标记的应用进展。同时,对其存在的问题进行了讨论,并展望了该标记的发展应用前景。     

红豆越桔VviDREB1基因转化烟草的研究

通过构建pVB4215植物双元表达载体,采用农杆菌介导法转化烟草,研究VviDREB1在植物体中的异源表达特性.结果显示,实验获得了25个Hyg抗性株系,经过PCR、RT-PCR和GUS组织化学染色检测及Hyg基因的PCR复检等多点验证,证实表达载体边界内序列完整地整合到2个烟草株系的基因组中.转基因烟草株系在4℃低温处理20 h后,恢复生长5 h,叶片光系统PSⅡ抗寒性分析结果表明,转基因植株的叶片快速叶绿素荧光曲线OJIP各点数值高于对照植株,VviDREB1基因能够显著提高烟草的荧光产量,最大光化学效率Fv/Fm和以吸收光能为基础的性能指数PIABS较对照高,说明VviDREB1对保护植物组织细胞内光合系统PSⅡ有明显的作用,转VviDREB1基因烟草对低温有一定的忍耐能力.     

Testing the function of the domed nests of Saltmarsh Sharp-tailed Sparrows

ABSTRACT.   Saltmarsh Sharp-tailed Sparrows ( Ammodramus caudacutus ) build ground nests, often with a closely-woven dome, in marshes that frequently flood during high tides. To test the hypothesis that domed nests help reduce the loss of eggs and chicks due to flooding or predation, we examined the characteristics and fate of 102 nests at sites along the coast of Connecticut. To test whether nest structure was tailored to suit microhabitat conditions, we also measured vegetation characteristics around nests. Finally, we conducted artificial nest-flooding experiments to determine whether removal of domes reduced egg retention during flooding. We found no significant effects of nest structure on breeding success or failure, and few significant correlations between nest structure and microhabitat. The height of nests above the ground, however, increased with vegetation height, supporting the hypothesis that nest construction is influenced by flooding, but not supporting the hypothesis that predation risk is important. Dome removal experiments showed that domes have a highly significant effect on the retention of eggs during flooding, suggesting that domes help eggs survive the regular tidal flooding of marshes.     

Photosynthetically versatile thin shade leaves: A paradox of irradiance-response curves

Thick sun leaves have a larger construction cost per unit leaf area than thin shade leaves. To re-evaluate the adaptive roles of sun and shade leaves, we compared the photosynthetic benefits relative to the construction cost of the leaves. We drew photosynthetically active radiation (PAR)-response curves using the leaf-mass-based photosynthetic rate to reflect the cost. The dark respiration rates of the sun and shade leaves of mulberry (Morus bombycis Koidzumi) seedlings did not differ significantly. At irradiances below 250 μmol m⁻² s⁻¹, the shade leaves tended to have a significantly larger net photosynthetic rate (P _N) than the sun leaves. At irradiances above 250 μmol m⁻² s⁻¹, the P _N did not differ significantly. The curves indicate that plants with thin shade leaves have a larger daily CO₂ assimilation rate per construction cost than those with thick sun leaves, even in an open habitat. These results are consistently explained by a simple model of PAR extinction in a leaf. We must target factors other than the effective assimilation when we consider the adaptive roles of thick sun leaves.     

Field patterns of leaf plasticity in adults of the long-lived evergreen Quercus coccifera

BACKGROUND AND AIMS: Quercus coccifera, as a long-lived sprouter, responds plastically to environmental variation. In this study, the role of foliar plasticity as a mechanism of habitat selection and modification within the canopy and across contrasted habitats was characterized. An examination was made of the differential contribution of inner and outer canopy layers to the crown plasticity expressed in the field by adult individuals and its dependence on environmental and genetic factors. METHODS: Within-crown variation in eight foliar traits was examined in nine populations dominated by Q. coccifera. The difference between mean trait values at the inner and outer canopy layers was used as a proxy for crown plasticity to light. Correlations between geographic distances, environmental differences (climatic and edaphic) and phenotypic divergence (means and plasticities) were assessed by partial Mantel tests. A subset of field measurements was compared with data from a previous common garden experiment. KEY RESULTS: Phenotypic adjustment of sun leaves contributed significantly to the field variation in crown plasticity. Plasticity in leaf angle, lobation, xanthophyll cycle pigments and beta-carotene content was expressed in sun and shade leaves concurrently and in opposite directions. Phenotypic plasticity was more strongly correlated with environmental variation than mean trait values. Populations of taller plants with larger, thinner (higher specific leaf area) and less spiny leaves exhibited greater plasticity. In these populations, the midday light environment was more uniform at the inner than at the outer canopy layers. Field and common garden data ranked populations in the same order of plasticity. CONCLUSIONS: The expression of leaf plasticity resulted in a phenotypic differentiation that suggests a mechanism of habitat selection through division of labour across canopy layers. Signs of plasticity-mediated habitat modification were found only in the most plastic populations. Intracanopy plasticity was sensitive to environmental variation but also exhibited a strong genetic component.