A phytosociological study of weed communities on the southwestern Coastal Plain of North Carolina

Summary The vegetation of cultivated, fallow and ‘old’ fields of Scotland County, N.C. was both randomly and subjectively sampled throughout the growing season of 1973. Relevés were placed in each of the above management units, and the data collected in this relevé analysis were sorted into phytosociological charts, with the aid of the digital computer. Weed associations delimited in the charts reflected the importance of edaphic factors, time (aspect), and man's agricultural activities as causal factors in the determination of characteristic assemblages of weeds. Several character and differential species were denoted, in a tentative classification of the weed associations. The cultivated and fallow stands in the spring aspect were noted to be dominated by a group of spring annuals. Summer annuals were more prevalent in homologous situations in the summer. It was determined that perennials, appearing mainly as seedlings in cultivated and fallow fields, attained dominance in ‘old’ fields, one to five years in age. Within each of the major spheres of management, and in each season, associations of weeds mainly reflected differences in edaphic factors. Many character species were noted to maintain affinities to an assortment of soil types that ranged from moist loams to xeric, sterile sands. A study of roadsides, hedgerows, field margins and other ecotonal areas inhabited by weeds was carried throughout the growing season of 1973, also. Species presence was documented in each of these habitat types and reported in Sharp (1974). The weed flora of Scotland County was found to be rich in species. A total of 506 species representing 248 genera and 80 families were encountered throughout the study. Of the total number of species listed, approximately 25 percent were of foreign origin, and 28 percent represented additions to the flora of Scotland County. This paper is the short version of a masters thesis for the Department of Botany, University of North Carolina at Chapel Hill. The author would like to extend his appreciation and gratitude to Professors H. Lieth, A. E. Radford and J. Hardin for their generous advice and encouragement extended through the duration of the study.     

The application of biomechanical motion analysis to aspects of green monkey (Cercopithecus a. sabaeus) locomotion

A cinematographic method of biomechanical motion analysis is presented which permits the determination of body segment forces and joint moments of force, and thereby dominant muscle action. An analysis of the horizontal leap of Cercopithecus is used as an example of the utility of this approach in the area of functional morphology. Kinematic and kinetic data are presented and discussed in terms of the biomechanical requirements of this form of locomotion. The importance of a consideration of inertial as well as gravitational forces in an analysis of positional behavior involving body motion is stressed.     

Multivariate analysis of Gigantopithecus mandibles

Multivariate analysis of measurements of the teeth and mandibles of Gigantopithecus species has been conducted, using several methods. Results indicate Gigantopithecus is an aberrant form, less related to australopithecines and gorillas than the latter are to each other. Gracile and robust australopithecines differ considerably more than do male and female gorillas.     

苹果柠檬酸合酶3基因家族成员鉴定及表达分析

柠檬酸合酶(citrate synthase 3, CS3)是细胞代谢途径中的关键酶之一,其活性调节着生物体的物质和能量代谢过程。本研究旨在从苹果全基因组中鉴定CS3基因家族成员,并进行生物信息学和表达模式分析,为研究苹果CS3基因的潜在功能提供理论基础。利用BLASTp基于GDR数据库鉴定苹果CS3家族成员,通过Pfam、SMART、MEGA5.0、clustalx.exe、ExPASy Proteomics Server、MEGAX、SOPMA、MEME和WoLF PSORT等软件分析CS3蛋白序列基本信息、亚细胞定位情况、结构域组成、系统进化关系以及染色体定位情况。利用酸含量的测定和实时荧光定量PCR (real-time fluorescence quantitative polymerase chain reaction, qRT-PCR)技术检测苹果6个CS3的组织表达和诱导表达特性。苹果CS3基因家族包含6个成员,这些CS3蛋白包括473−608个不等的氨基酸残基,等电点分布在7.21−8.82。亚细胞定位结果显示CS3蛋白分别定位在线粒体和叶绿体。系统进化分析可将其分为3类,各亚家族基因数量分别为2个。染色体定位结果显示,CS3基因分布在苹果不同的染色体上。蛋白二级结构以a-螺旋为主,其次是无规则卷曲,b-转角所占比例最小。筛选的6个家族成员在不同苹果组织中均有表达,整体表达趋势从高到低依次为MdCS3.4相对表达含量最高,MdCS3.6次之,其他家族成员相对表达量依次为MdCS3.3>MdCS3.2>MdCS3.1>MdCS3.5。qRT-PCR结果显示,MdCS3.1和MdCS3.3基因在酸含量较低的‘成纪1号’果肉中相对表达量最高,酸含量较高的‘艾斯达’果肉中MdCS3.2和MdCS3.3基因相对表达量最高。因此,本研究对不同苹果品种中CS3基因相对表达量进行了检测,并分析了其在苹果果实酸合成过程中的作用。结果表明,CS3基因在不同苹果品种中的相对表达量存在差异,为后续研究苹果品质形成机制提供了参考。     

斑马鱼急性无机砷暴露后肝脏差异表达基因的生物信息学分析

砷是一种致癌物,是心血管、外周血管疾病、神经疾病、糖尿病和各种癌症的致病因素。目的:利用GO数据库和KEGG数据库等生物信息学方法对GEO数据库数据中的差异表达基因进行评价。利用生物信息学分析软件对差异基因进行功能富集、功能注释分析和生存分析。利用Cytoscape上的蛋白-蛋白相互作用网络(Protein-protein interaction network, PPI)软件对179个差异基因进行筛选和分析。结果发现126个基因作用于蛋白靶点,其中有10个基因为关键基因分别为:PSMB3、HSP701、HSPE1、STIP1、HSPD1、HSP70、DNAJB1B、HSP90AA1.1、HSPA9H和TCP1。核心基因主要作用于内质网中的蛋白质加工通路。这可能会为砷对肝脏损伤的潜在生物标志物和生物学机制提供新的思路。     

转录因子在植物干旱应激中的功能研究进展

转录因子是一种多功能蛋白,在感知应激信号、应答相应应激基因表达及传导应激信号中起着关键作用。干旱是影响植物生长发育的主要非生物胁迫之一。为了适应干旱环境,植物发展了复杂的分子机制,其中转录因子可同时控制多种途径调控干旱应激,是操纵调控和应激响应途径的有力工具。近年来,越来越多的植物转录因子的功能被阐明,了解转录因子在干旱应激的功能,对植物的工程抗旱有重要的实践意义。综述转录因子在植物干旱应激中的功能研究进展,以期为今后转录因子的研究和利用提供理论依据,培育具有较强抗旱能力的植物。     

Composition and spatial heterogeneity of submersed vegetation in a softwater lake in Wisconsin

Big Muskellunge Lake, a softwater lake (pH 7.5–8.0, alkalinity 0.36 meq/L) in northern Wisconsin, harbors a diverse (25 species) submersed macrophyte vegetation. The present submersed flora combines species generally thought distinct in their ecological affinities, and is very similar to that reported in 1935. The only differences are the apparent loss of three previously infrequent Potamogeton species, and the addition to the flora of two infrequent Potamogeton species and the now abundant Elodea canadensis. Dramatic differences in composition and pattern of the vegetation occurred between sites of contrasting exposure and sediment type. Substantial compositional variation, at scales ranging from tens of centimeters to tens of meters, occurred along transects of contiguous quadrats at uniform depth and exposure. Analyses of species sequences along line transects detected significant segregation of species that is most plausibly explained by biotic factors such as colonization, clonal growth, and competition. Heterogeneity at small scales of a few meters or less is common in Big Muskellunge Lake. Such pattern has been neglected in macrophyte ecology, in spite of its significance for neighbor relationships which may critically influence growth and reproduction of aquatic plants.