Differences in seed dormancy and germination in amphicarpic legumes: manifold bet-hedging in space and time

两型结实豆科植物种子休眠和萌发的差异：空间和时间上多样性的两头下注策略 通过休眠而实现的在空间或时间上的传播是生物体对它们所经历的环境施加影响的主要过程之一。在植物中，由于这两种传播都是通过种子进行的，而且两者在适应性方面发挥的作用也是类似的，因此预测它们之间存在较强的进化相关性。在本研究中，我们使用了两型结实的植株来研究这些进化相关性，这类植株能同时产生具有高度空间传播力的种子以及不会传播的地下种子。我们对经不同组合的休眠过程破坏处理(即干燥后熟、冷积层和物理划伤)后的种子的萌发百分比进行了评估，以研究两种两型结实豆科植物——野豌豆(Vicia amphicarpa L.)和山黧豆(Lathyrus amphicarpos L.)，以及同它们亲缘关系很近的两种单型结实类群——救荒野豌豆(Vicia sativa L.)和红山黧豆(Lathyrus cicera L.)的飞播种子和地下种子在休眠和萌发方面的变化情况。研究结果表明，空间传播和时间传播之间存在着复杂的相互作用。在刚完成传播时，空播种子比地下种子更具休眠性，但当种子经后熟处理而开始物理休眠时，这种趋势也随之逆转。单型结实植株种子的萌发百分比高于其两型结实的同属植株，并在后熟处理后都同样失去了休眠性。相反，两型结实植株的种子则表现出同时受生理休眠和物理休眠调节的不同休眠性策略，预计这可能使出苗时间发生变化，从而提供了多层次多样化的两头下注策略(bet-hedging)。这一策略能够使植株依赖于丰产季中的历史有利区域而不阻碍空间和时间上的迁移，从而有可能在不可预测性很高的条件下具有适应性。     

Comparison of binding characteristics of endothelin receptors on subpopulations of astrocytes.

Astrocytes in primary culture originating from different brain areas of the mouse embryo (striatum, cerebral cortex and mesencephalon) were compared for their [125I]-Endothelin-1 (ET-1) binding characteristics, in terms of affinity, binding capacity and specificity. Our results indicate that astrocytes from mesencephalon express about twice as many receptors as astrocytes from striatum or cortex (149,000 +/- 9700 vs 63,700 +/- 5600 and 81,900 +/- 5300, respectively), with similar affinities. Specificity patterns for the various peptides of the endothelins/sarafotoxins family (ET-1, -2, -3; SRTXa, b, c) are comparable in the three subpopulations of astrocytes: ET-1, -2 and SRTXb exhibit higher affinities than SRTXa and SRTXc. In addition, ET-3 and SRTXc seem to discriminate between different subsets of [125I]-ET-1 binding sites in the three subpopulations.     

Anticipated effects of abiotic environmental change on intraspecific social interactions

Social interactions are ubiquitous across the animal kingdom. A variety of ecological and evolutionary processes are dependent on social interactions, such as movement, disease spread, information transmission, and density-dependent reproduction and survival. Social interactions, like any behaviour, are context dependent, varying with environmental conditions. Currently, environments are changing rapidly across multiple dimensions, becoming warmer and more variable, while habitats are increasingly fragmented and contaminated with pollutants. Social interactions are expected to change in response to these stressors and to continue to change into the future. However, a comprehensive understanding of the form and magnitude of the effects of these environmental changes on social interactions is currently lacking. Focusing on four major forms of rapid environmental change currently occurring, we review how these changing environmental gradients are expected to have immediate effects on social interactions such as communication, agonistic behaviours, and group formation, which will thereby induce changes in social organisation including mating systems, dominance hierarchies, and collective behaviour. Our review covers intraspecific variation in social interactions across environments, including studies in both the wild and in laboratory settings, and across a range of taxa. The expected responses of social behaviour to environmental change are diverse, but we identify several general themes. First, very dry, variable, fragmented, or polluted environments are likely to destabilise existing social systems. This occurs as these conditions limit the energy available for complex social interactions and affect dissimilar phenotypes differently. Second, a given environmental change can lead to opposite responses in social behaviour, and the direction of the response often hinges on the natural history of the organism in question. Third, our review highlights the fact that changes in environmental factors are not occurring in isolation: multiple factors are changing simultaneously, which may have antagonistic or synergistic effects, and more work should be done to understand these combined effects. We close by identifying methodological and analytical techniques that might help to study the response of social interactions to changing environments, highlight consistent patterns among taxa, and predict subsequent evolutionary change. We expect that the changes in social interactions that we document here will have consequences for individuals, groups, and for the ecology and evolution of populations, and therefore warrant a central place in the study of animal populations, particularly in an era of rapid environmental change.     

Immunohistochemistry of the guinea-pig trachea using an anti-idiotypic antibody recognizing substance P receptors

The airways receive a dense innervation from sensory neurons containing substance P (SP). An anti-SP anti-idiotypic antibody (anti-Id ab) recognizing SP receptors was previously characterized pharmacologically and proved to be useful in immunohistochemistry of the central nervous system. This antibody was used to localize SP binding sites in the guinea-pig trachea by immunohistochemistry. Immunolabelling was considered as specific when it could be prevented by a) preabsorption of the anti-Id ab with a C-terminal specific monoclonal anti-SP antibody, and b) preincubation of the tissue sections with either of the tachykinins, substance P and neurokinin A, in the presence of the inhibitor of neutral endopeptidase, phosphoramidon, and addition of these compounds into the antibody incubation medium. Moreover, immunofluorescence was absent when the acetone-fixed of fresh frozen sections were exposed to the detergent Tween 20 prior to immunohistochemistry, which points to a membrane localization of the detected tissue antigen, as expected for SP receptors. Compared with previous reports on autoradiographic localization of SP receptors in the guinea-pig trachea, the present immunohistochemical approach proved to be superior in enabling discrimination of labelled elements: Trachealis muscle, cylindrical epithelial cells and some roundish, singly lying cells in the epithelium and subepithelial lamina propria displayed specific immunofluorescence. These morphological findings match well with the known pharmacological actions of SP on the guinea-pig trachea.     

Variation of substance P-like immunoreactivity in plasma and cerebrospinal fluid in the course of arthritis induced by Freund adjuvant in rats, a model for the study of chronic pain

Parallel time courses of clinical and behavioural parameters and levels of plasma substance P-like immunoreactivity (SPLI-PI) were studied in arthritic rats (adjuvant induced arthritis, AIA, a chronic pain model). Acute (14 and 21 post-inoculation days,PI) and post-acute (42 days PI) phases of the syndrome were investigated. These data were compared with those obtained in a control situation (inoculation day). In a second experimental series, levels of substance P-like immunoreactivity in cerebrospinal fluid (SPLI-CSF) were determined at the same stages of AIA. In arthritic rats SPLI-PI was strongly enhanced (X4) as early as 14 days PI and remained increased (X4) at all stages studied, whereas SPLI-LCR was significantly increased (X2) only 21 days PI and returned to control levels at 42 days PI. These data suggest that SP could be distributed in two different pools, a peripheral one of inflammatory origin, and a central one which could be more specific to the chronic pain situation.