Maternal influences on offspring phenotypes and sex ratios in a multi‐clutching lizard with environmental sex determination

Maternal and environmental factors are important sources of phenotypic variation because both factors influence offspring traits in ways that impact offspring and maternal fitness. The present study explored the effects of maternal factors (maternal body size, egg size, yolk‐steroid allocation, and oviposition‐site choice) and seasonally‐variable environmental factors on offspring phenotypes and sex ratios in a multi‐clutching lizard with environmental sex determination (Amphibolurus muricatus). Maternal identity had strong effects on offspring morphology, but the nature of maternal effects differed among successive clutches produced by females throughout the reproductive season (i.e. maternal identity by environment interactions). The among‐female and among‐clutch variation in offspring traits (including sex ratios) was not mediated through maternal body size, egg size, or variation in yolk steroid hormones. This lack of nongenetic maternal effects suggests that phenotypic variation may be generated by gene by environment interactions. These results demonstrate a significant genetic component to variation in offspring phenotypes, including sex ratios, even in species with environmental sex determination. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 256–266.     

At-line quantification of bioactive antibody in bioreactor by surface plasmon resonance using epitope detection

We report an innovative at-line method to monitor concentration of bioactive antibody (i.e., antibody with conserved antigen-binding activity) secreted during bioreactor culture by the use of surface plasmon resonance (SPR)-based biosensor technology. In a first series of experiments, conditions for SPR-based measurements were validated off-line by monitoring bioactive antibody concentration in conditioned medium from 500-ml baffled flask hybridoma cell cultures. A fully automated experimental setup in which the SPR-based biosensor was harnessed to a bioreactor was then used at-line to monitor the concentration of bioactive antibody produced in a 3.5-L bioreactor. Quantitative SPR measurements performed both at-line and off-line were in excellent agreement with quantitative Western blotting followed by densitometry analyses. Thus, our experimental study confirms that SPR biosensors can be applied to at-line quantification of correctly folded proteins that are secreted by cells cultured in a bioreactor. Our experimental approach represents a novel and robust analytical strategy to be applied to the control and optimization of the production of bioactive secreted proteins.     

用粪粒外部形态指标鉴定海南坡鹿的性别与年龄

利用粪便形态指标鉴定有蹄类动物的性别和年龄对研究不同性别年龄个体的生态学和性别分离具有重要价值。利用2006年3月在海南大田国家级自然保护区采集的145头(次)已知性别和年龄组的野生海南坡鹿(Cervus eldi hainanus)粪便4006粒,将坡鹿划分为成年雄鹿、成年雌鹿、亚成年雄鹿、亚成年雌鹿和幼鹿5个性别年龄组,使用逐步判别分析和聚类分析对粪粒的4项直接测度指标(干重、体积、长轴长、短轴长)以及2项间接测度指标(长短轴比和椭球形状指数)进行分析。结果表明:逐步判别分析对海南坡鹿粪粒的性别年龄组正判率为成年雄鹿76.17%、成年雌鹿42.22%、亚成年雄鹿34.94%、亚成年雌鹿40.46%、幼鹿79.34%,聚类分析的判别率为成年雄鹿19.48%、成年雌鹿20.02%、亚成年雄鹿37.37%、亚成年雌鹿42.82%、幼鹿91.50%。利用粪粒形态判别海南坡鹿的性别年龄组最可靠的是幼鹿,次之为成年雄鹿。利用粪粒形态判别海南坡鹿的性别年龄组可以应用于以取样原理进行的群体水平研究,但个体水平上的性别和年龄鉴定由于判别误差较大而难以应用。     

遗传学教学中性别决定关键基因的阐述

有性生殖的出现是生物进化中的重大事件。性别作为生物的一种重要而又复杂的表型, 由基因和环境因素共同控制, 其中遗传因素即基因起到非常关键的作用。 然而, 并不是每个相关基因对于生物的性别都具有相同的作用, 性别决定关键基因对生物性别的决定和性别的分化具有重要作用, 因而研究和理解性别决定的关键基因具有重要意义。随着现代遗传学的发展, 目前关于生物性别决定方式以及性别决定关键基因的研究已取得了很大的进展。文章就生物的基因性别决定机制以及基因性别决定机制的研究策略进行了综述, 以期在遗传学教学中能更好地理解和阐述。     

Conspecific and Interspecific Interactions Between the FEM-2 and the FEM-3 Sex-Determining Proteins Despite Rapid Sequence Divergence

Using degenerate oligonucleotide primers, we isolated the Caenorhabditis remanei orthologue of the C. elegans sex-determining phosphatase gene fem-2 as well as two other protein phosphatase homologues. Despite the significant sequence divergence between C. elegans and C. remanei FEM-2, we used RNAi-mediated gene knockdown to demonstrate that at least some aspects of male development require FEM-2 function in C. remanei. Consistent with this functional conservation, the conspecific interaction between the FEM-2 and the FEM-3 proteins observed in C. elegans also occurs in C. remanei. To further explore whether the rapid evolution of FEM-2 and FEM-3 affects their molecular interactions, we tested for cross-species interactions between the proteins from C. elegans, C. briggsae, and C. remanei. Although all FEM-2/FEM-3 pairs from a single species interact, only two out of six interspecific pairs bind each other, showing that FEM-2 and FEM-3 are coevolving. Both interspecific interactions involved C. briggsae FEM-3. We constructed chimeric versions of FEM-2 consisting of various combinations of the C. elegans and C. remanei proteins. C. briggsae FEM-3 interacted with all the chimeras, even those that did not interact with either C. elegans or C. remanei FEM-3. We hypothesize that the promiscuity of C. briggsae FEM-3 reflects an increased reliance on evolutionarily constrained regions of FEM-2 for binding. If so, our data support the notion that the coevolution of two interacting proteins sometimes involves a shift in the domains that contribute to binding. [Reviewing Editor: Dr. Willie J. Swanson]     

Indole acetic acid (IAA) induced changes in growth, relative water contents and gas exchange attributes of barley (Hordeum vulgare L.) grown under water stress conditions

Effect of different concentrations of indole acetic acid (IAA) under varying soil water deficit conditions on two barley cultivars viz. B-99094 and Jau-87 was investigated in soil filled earthen pots. There were six treatments including control each with four replicates. Three concentrations of IAA (0, 15 and 30 mg l⁻¹) were applied as foliar spray 30 days after germination. After hormone application, half of the pots were subjected to one cycle of water stress (withholding of water till incipient wilting), followed by regular watering. Plant height, photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency relative water content, dry biomass, and grain yield/plant were significantly reduced by water stress. However, IAA treatments alleviated the adverse effect of water stress and successful in enhancing the plant growth and yield of barley cultivars. Barley cultivar Jau-87 performed better than B-99094. IAA application␣was effective in enhancing growth and photosynthetic efficiency of barley both under normal and water stress conditions.     

高效液相色谱法测定山栀子中栀子甙的含量

采用高效液相色谱法测定中药山栀子（Cardenia jasminoides Ellis）中保肝利胆的主要成分栀子甙（geniposide）的含量。分析结果表明,本方法重现性好,平均加样回收率为100．90％,RSD为2．00％。用此方法测定未知样品山栀子中栀子甙的平均含量为3．463g/100g。     

Evaluation of the age of the red whelk Neptunea antiqua using statoliths, opercula and element ratios in the shell

Growth rings present in whole and sectioned statoliths were used to determine the age of red whelks Neptunea antiqua, from the North Sea. Validation of the periodicity of the rings was established in four whelks by comparing the number of statolith rings with the number of seasonal Mg:Ca ratio cycles present in shell calcium carbonate samples drilled sequentially from along the growth axis. There was exact correspondence between the number of growth rings and the number of element ratio cycles in two of the shells and a 1-year difference in the estimated age between the two methods in the other two shells, evidence which is strongly indicative of an annual periodicity of deposition to the statolith rings. The estimated age of the whelks using the statolith rings varied between 4 years (shell length 102 mm) and 17 years (shell length 148 mm). The age of the whelks ascertained from the statoliths was compared with age estimates from the number of adventitious layers in sectioned opercula. The number of adventitious layers in whelks from 51 to 148 mm shell length ranged between 1 and 12 years. No significant difference was observed between the number of strongly defined statolith rings and number of opercula adventitious layers.