Chemiluminescent immunoassay of thyroxine enhanced by microchip electrophoresis

A homogeneous chemiluminescent immunoassay of thyroxine (T4) enhanced by microchip electrophoresis separation has been developed. The method deployed the competitive immunoreaction of T4 and horseradish peroxidase (HRP)-labeled T4 (HRP-T4) with anti-T4 mouse monoclonal antibody (Ab). HRP-T4 and the HRP-T4-Ab complex were separated and quantified by using microchip electrophoresis (MCE) with chemiluminescence (CL) detection. Highly sensitive CL detection was achieved by means of HPR-catalyzed luminol-H₂O₂ reaction. Due to the effective MCE separation, the CL analytical signal was less prone to sample matrix interference. Under the selected assay conditions, the MCE separation was accomplished within 60 s. The linear range for T4 was 5-250 nM with a detection limit of 2.2 nM (signal/noise ratio = 3). The current method was successfully applied for the quantification of T4 in human serum samples. It was demonstrated that the current MCE-CL-enhanced competitive immunoassay was quick, sensitive, and highly selective. It may serve as a tool for clinical analysis of T4 to assist in the diagnosis of thyroid gland functions.     

Housing condition alters immunological and reproductive responses to day length in Siberian hamsters (Phodopus sungorus)

During winter, increased thermoregulatory demands coincide with limited food availability necessitating physiological tradeoffs among expensive physiological processes resulting in seasonal breeding among small mammals. In the laboratory, short winter-like day lengths induce regression of the reproductive tract, but also enhance many aspects of immune function. It remains unspecified the extent to which bolstered immune responses in short days represent enhanced immune function per se compared to long days or represents energetic disinhibition mediated by the regression of the reproductive tract. Cohabitation of male Siberian hamsters with intact female conspecifics can block short-day reproductive regression. We sought to determine whether female cohabitation could also block the enhanced immune function associated with short days. Adult male Siberian hamsters were housed in long or short day lengths in one of three housing conditions: (1) single-housed, (2) housed with a same sex littermate, or (3) housed with an ovariectomized female. Delayed-type hypersensitivity (DTH) responses were assessed after 8 weeks of photoperiod treatment. Housing with an ovariectomized female was not sufficient to block short-day reproductive regression, but prevented short-day enhancement of DTH responses. Housing with a male littermate did not alter reproductive or immune responses in either photoperiod. These data suggest that short day enhancement of immune function is independent of photoperiod-mediated changes in the reproductive system.     

Why does some pollen lack apertures? A review of inaperturate pollen in eudicots

Apertures are key characters of pollen grains with systematic importance in angiosperms. They function as sites for pollen tube exit, water uptake, transfer of recognition substances and accommodation of volume changes. Not all pollen has apertures; inaperturate pollen (lacking obvious apertures) characterizes many angiosperm groups, especially in early divergent angiosperms and monocots, but also eudicots. In order to expand our knowledge of the systematic distribution, possible functional significance and development of inaperturate pollen in angiosperms, this review focuses on inaperturate and cryptoaperturate (with hidden apertures) pollen in the large eudicot clade, which comprises about 75% of present‐day angiosperm species. It includes new TEM observations of inaperturate pollen from four exemplar taxa selected from different parts of the eudicot phylogeny. Two categories of inaperturate (including cryptoaperturate) pollen occur in eudicots. (1) Sterile attractant or feeding pollen associated with functional dioecy has evolved iteratively at least six times in conjunction with complex breeding systems in the core eudicots. (2) Fertile pollen has evolved numerous times independently throughout eudicots, though generally in a relatively small number of individual taxa. Notable exceptions are the petaliferous crotonoid Euphorbiaceae s.s., in which fertile inaperturate pollen occurs in c. 1500 species, and two subfamilies of Apocynaceae s.l. (Secamonoideae and Asclepiadoideae) with c. 2500 species with fertile inaperturate pollen in pollinia. Fertile inaperturate pollen is sometimes (but not always) associated with an aquatic habit, parasitism, insectivory, heterostyly, anemophily or pollinia. Most fertile inaperturate pollen has a thin exine, or the exine is largely restricted to isolated components (muri, protuberances, subunits) separated by thinner areas which probably function as apertures. In cryptoaperturate pollen, the aperture is covered by continuous exine which probably has a protective function, similar to an operculum. Developmentally, inaperturate pollen is not associated with any particular tetrad type or meiotic spindle orientation (unlike some apertures) due to the absence of a colpal shield of endoplasmic reticulum or other organelles and hence is independent of microsporogenesis type. The lack of a colpal shield during the tetrad stage of development permits complete deposition of first primexine and then exine around each microspore, possibly mediated by the action of the DEX1 protein. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155 , 29–48.     

Effects of Hatchery Rearing on Brain Structures of Rainbow Trout, Oncorhynchus mykiss

In this study, we contrast brain morphology from hatchery and wild reared stocks to examine the hypothesis that in salmonid fishes, captive rearing produces changes in brain development. Using rainbow trout, Oncorhynchus mykiss, as a model, we measured eight regions of the salmonid brain to examine differences between wild and hatchery reared fish. We find using multiple analysis of covariance (MANCOVA), analysis of covariance (ANCOVA) and discriminant function analysis (DFA) that the brains of hatchery reared fish are relatively smaller in several critical measures than their wild counterparts. Our work may suggest a mechanistic basis for the observed vulnerability of hatchery fish to predation and their general low survival upon release into the wild. Our results are the first to highlight the effects of hatchery rearing on changes in brain development inbreak fishes.     

Relating Species and Community Dynamics in an Heavily Exploited Marine Fish Community

We examined the dynamics of fish species and how they relate to species assemblage coherence in the heavily exploited Georges Bank fish community. Coherence is defined as reduced temporal variability of total assemblage biomass. We assumed that a higher degree of compensation hence coherence occurs within competitively coupled species assemblages; therefore, fisheries may directly alter the dynamics of certain targeted species sizes but assemblage structure will be relatively more stable owing to compensatory interactions. Species-sizes were grouped, based on negative covariance coupling in biomass time series from survey data. Assemblages representing benthic feeders were clearly identified by this method; furthermore, the most heavily exploited species-sizes were decoupled from other species-sizes suggesting that fisheries have diminished their potential to compensate or to be compensated for by competitive interactions. Biomass of species-sizes within known trophic guilds strongly compensated other guild-member biomass fluctuations if the diet of guild members was more specialized. This is an indication that more competitive conditions (more specialization) foster greater compensatory responses between competitors biomass fluctuations.     

心率变异性评估运输应激对Beagle犬自主神经功能的影响

目的 基于心率变异性(heart rate variability,HRV)分析评估运输应激对Beagle犬自主神经功能的影响,并界定其恢复期.方法 16只Beagle犬随机分成两组(每组8只),即对照组和运输应激组,利用大动物无创生理信号遥测技术,分别监测清醒自由活动状态下对照组和运输应激组应激4 h后、恢复1、2、...     

高温胁迫下五种杜鹃花属植物的生理变化及其耐热性比较

高温是制约分布于较高海拔地区杜鹃花迁地保育与园林应用的重要因子.为探讨杜鹃花属植物的 高温致伤机理,该实验以隶属不同亚属的白花杜鹃、羊踯躅、毛棉杜鹃、红滩杜鹃及红棕杜鹃4年生实生苗为 材料,通过人工气候箱的盆栽实验,研究了30℃、38℃高温胁迫下其叶片生理生化指标的变化,并利用隶属 函数法及系统聚类分析法对其种间...     

小尺度森林生态功能分区研究——以台湾惠荪林场为例

基于景观生态学中结构与功能相互依存的理念 ,选定小尺度森林为研究对象 ,根据生态系统内部结构特性 ,确立森林生态功能的空间定位 ,以提高森林生态系统的功能与价值。研究首先基于森林生态系统具有生物生产、环境服务及文化支持等基本功能 ,提出上述功能应通过森林生产、教学实习、科学研究、休闲游憩和生态保护等功能区加以体现。后依据研究区环境特征进行影响因子分析 ,结合景观生态与生态规划相关理论 ,构建森林生态功能分区方案。在案例实践中 ,选择台湾惠荪林场进行研究 ,配合研究区现况 ,期望通过功能区与结构的空间调整 ,达到服务功能的优化。     

Altruistic self‐removal of health‐compromised honey bee workers from their hive

Social insect colonies represent distinct units of selection. Most individuals evolve by kin selection and forgo individual reproduction. Instead, they display altruistic food sharing, nest maintenance and self‐sacrificial colony defence. Recently, altruistic self‐removal of diseased worker ants from their colony was described as another important kin‐selected behaviour. Here, we report corroborating experimental evidence from honey bee foragers and theoretical analyses. We challenged honey bee foragers with prolonged CO₂ narcosis or by feeding with the cytostatic drug hydroxyurea. Both treatments resulted in increased mortality but also caused the surviving foragers to abandon their social function and remove themselves from their colony, resulting in altruistic suicide. A simple model suggests that altruistic self‐removal by sick social insect workers to prevent disease transmission is expected under most biologically plausible conditions. The combined theoretical and empirical support for altruistic self‐removal suggests that it may be another important kin‐selected behaviour and a potentially widespread mechanism of social immunity.     

绿洲农业生态经济系统的结构与功能分析以张掖绿洲为例

通过分析张掖绿洲农业生态经济系统的结构与功能,发现其种群结构单一、产业结构不甚合理、空间结构脆弱,决定了绿洲功能较差,产投比低下的特点,并据此从可持续发展的角度提出了改善绿洲农业生态经济系统结构、提高其功能的对策与建议