Humidity and seasonality drives body size patterns in males of the bush cricket Isophya rizeensis Sevgili, 2003 （Orthoptera： Tettigoniidae： Phaneropterinae）

Two primary patterns of body size variation have been recorded in ectotherms in relation to latitudinal/altitudinal shifts. In some, body size increases with increasing latitude/altitude whereas, in others, body size decreases with increasing latitude/altitude. This clinal variation is generally assumed to be caused by local adaptation to environmental conditions however the selective variable（s） （temperature, humidity, diet quality, etc.） is still heavily debated. Here we investigate geographic variation in body size of dark and pale color morphs of males of the bush-cricket lsophya rizeensis collected from 15 locations along an elevation gradient ranging from 350 to 2 500 m. Using an information theoretical approach we evaluate the relative support of four different hypotheses （the temperature size rule, the moisture gradient hypothesis, the seasonal constraint hypothesis, and the primary productivity hypothesis） explaining body size variation along the altitudinal gradient. Body size variation in pale color morphs showed a curvilinear relationship with altitude while dark color morphs showed no variation in body size. Body size variation in pale color morphs was highly correlated with precipitation and temperature seasonality values thus giving strong support for the moisture gradient and seasonal constraint hypothesis. Our results reinforce the importance of gradients in humidity and seasonality over temperature in the creation of altitudinal body size clines and the role of selection for resistance to stress factors in the establishment of these clines. Whether a body size cline is observed or not might also depend on the phenotypic properties of the individuals, like coloration.     

Conditions for a heat shock response during oogenesis and embryogenesis of the amphibian Pleurodeles waltl

The optimal conditions capable of inducing an increase in HSP70 neosynthesis during development of the urodele amphibian Pleurodeles waltl were determined in this study. These conditions depend on temperature, heat shock duration and recovery duration. In oocytes, a heat shock response was repeatedly obtained at 37°C for 15 min followed by 1 h recovery. These results provided evidence for heat shock response at every stage considered. An increase in HSP70 synthesis was noted throughout oogenesis, but it did not lead to an increase in the amount of soluble HSP70, except for stage VI oocytes. Such results suggest that from stage II to stage IV oocytes, an equilibrium occurs between the HSP70 used and the HSP70 neosynthesized. In contrast, in stage VI oocytes, heat shock led to overproduction of HSP70. During early development, the heat shock response was repeatedly obtained only from the gastrula stage with a 37°C shock and a 15min duration of treatment. Surprisingly, during cleavage stage, the soluble HSP70 total amount increased after heat shock at a time when no HSP70 neosynthesis occurred.     

毛乌素裸沙丘斑块的实际蒸发量及其对降雨格局的响应

 裸沙表面的蒸发虽然是一个物理问题,但对于沙地植被演替的初始阶段非常重要。目前存在的地表蒸发的机理性模型大多是瞬时或者短时期的 ,而年尺度以上的蒸发量与降水和蒸发驱动下的土壤水分系统的状态变化及其对蒸发过程的反馈密切相关。一些估算毛乌素年蒸发量的实验结 果之间分歧很大且缺乏准确的机理性解释。该文利用生态系统模型中的土壤水分运动和蒸发模块计算了毛乌素裸沙丘从日到年际尺度的实际蒸 发量,发展了一个以单次降雨量和降雨频率为驱动因素的降雨-蒸发模型对年蒸发量进行简单的估算,并研究了年蒸发量对降雨格局的响应。结 果表明毛乌素裸沙丘的多年平均蒸发量为166 mm,占多年平均降雨量的56%。虽然研究区1959～1992年降雨总量无显著变化趋势,但是裸沙丘斑 块的实际蒸发量呈现较明显的增加趋势（1.30 mm&;#8226;a^－1）。小降雨事件对蒸发量贡献的显著增加（0.69 mm&;#8226;a^－1）是导致实际蒸发量增大的重 要原因。大强度降雨事件的频度和雨量对降雨总量的贡献要远高于对蒸发总量的贡献,小于12 mm的降雨事件在年际比较稳定,很大程度上保证 了年蒸发量100 mm左右的基数值。这些因素使得年蒸发量的变异程度小于年降雨量的变异程度。由于降雨格局的年际变化会对蒸发量产生直接 的影响,降雨-蒸发模型可以相对有效地预测年度蒸发量,而用年降雨量预测年蒸发量误差较大。     

All hosts are not equal: explaining differential patterns of malformations in an amphibian community

1. Within a community, different host species often exhibit broad variation in sensitivity to infection and disease. Because such differences can influence the strength and outcome of community interactions, it is essential to understand differential disease patterns and identify the mechanisms responsible. 2. In North American wetlands, amphibian species often exhibit extraordinary differences in the frequency of limb malformations induced by the digenetic trematode, Ribeiroia ondatrae. By coupling field studies with parasite exposure experiments, we evaluated whether such patterns were due to differences in (i) parasite encounter rate, (ii) infection establishment, or (iii) parasite persistence within hosts. 3. Field results underscored the broad variation in malformations and infection between host species; while nearly 60% (n = 618) of emerging American toads exhibited severe limb deformities such as bony triangles, skin webbings and missing limbs, fewer than 4% (n = 251) of Eastern gray treefrogs from the same pond were abnormal. Despite similarities in the phenology and larval development period of these species, they differed sharply in Ribeiroia infection. On average, toads supported 75x more metacercariae than did metamorphic treefrogs. 4. Experimental exposures of larval toads and treefrogs to a realistic range of Ribeiroia cercariae revealed strong differences in the sensitivity of these species to infection; exposed toads suffered elevated mortality (up to 95%), delayed metamorphosis, and severe limb malformations consistent with field observations. Treefrogs, in contrast, exhibited limited mortality and no malformations, regardless of exposure level. Ribeiroia cercariae were substantially less successful in locating and infecting Hyla versicolor larvae. 5. Our results indicate that the observed differences in infection and malformations owe to a lower ability of Ribeiroia cercariae to both find and establish within larval treefrogs, possibly stemming from a heightened immune response to infection. Because Ribeiroia is a highly pathogenic parasite with negative effects on larval and metamorphic amphibian survival, variation in infection resistance among species could have important implications for understanding patterns of species co-occurrence, competition, and community diversity.     

The influence of climatic conditions on the heat balance of the human body

The structure of heat exchange between the human body and its surroundings has been studied according to M.I. Budyko's model. Comparative measurements were carried out in the Polish Lakeland (maritime, temperate warm climate), in Central Mongolia (continental, temperate cool climate), and in the Kara Kum desert (dry subtropical climate). The results deal with the summer and early autumn seasons. The calculations indicate that the quantitative apportionment of various forms of heat exchange depend on specific weather conditions, which are typical for the distinguished climatic zones.     

章古台固沙林引起下垫面热量平衡特征变化的分析

章古台位于辽宁省西北部彰武县境内,是科尔沁沙地的东南前哨。50年代初期,本区主要由流动沙丘、半流动沙丘和丘间低地组成,生态环境十分恶劣。为了治理风沙危害,改变生态环境,1952年在该地区进行大面积樟子松造林。现已有林地2150ha,成功地将光秃的沙丘改造成翠绿的森林环境。显然,下垫面的这种变化不仅会带来该地区生态环境的改变,也将引起局地小气候尤其是热量平衡特征相应的     

Alterations in the Development of Rat Cerebellum and Impaired Behavior of Juvenile Rats after Neonatal 6-OHDA Treatment

The effects of neonatal systemic administration of the neurotoxin 6-hydroxydopamine (6-OHDA) on cerebellum development and behavior were studied in juvenile rats. The methods employed were immunohistochemistry, in situ hybridization, ligand binding, and behavioral testing. The results revealed, for the first time, that 6-OHDA treatment alters Bergmann glial cells and reduced the expression GABA_A receptor subtypes α1 and α6 especially in granule cells. The Bergmann glial cells were abnormally located and structurally different (e.g., no intimate associations with Purkinje cells). Significant microglial activation was also observed. The animals showed impairment in behavior, especially in their orientation to a novel environment. Recent data on neuron–glia interactions support the conclusion that the observed structural changes in Bergmann glia and granular neurons disrupted the normal functioning of the Purkinje cells which then in turn resulted in the impaired sensory-motor coordination at least in juvenile rats. This paper is a summary of previously published work and some recent data in this field obtained at our laboratory. Special issue dedicated to Dr. Simo S. Oja     

Maturation of neurites in mixed cultures of spinal cord neurons and muscle cells from Xenopus laevis embryos followed with antibodies to neurofilament proteins

Dissociated cell cultures of Xeopus laevis embryonic spinal cord have proved useful for studying the differentiation of neuronal ionic channel and membrane properties and for examining the dynamics of microtubules in developing neurons. To examine their usefulness for studying neurofilaments in developing neurites, we prepared similar cultures from stage 22 embryos. Between 3 and 55 h after plating, these cultures were fixed and immunostained with antibodies directed against various epitopes of neurofilament proteins from X. Laevis. These antibodies were specific for nonphosphorylated epitopes of the two low molecular weight Xenopus neurofilament proteins (Xenopus NF-L and the Xenopus neuronal intermediate filament protein, XNIF), both phosphorylated and nonphosphorylated epitopes of the Xenopus middle molecular weight neurofilament protein (NF-M), and a nonphosphorylated epitope of the Xenopus high molecular weight neurofilament protein (NF-H). The emergence of these neurofilament proteins in culture was compared to the time course previously reported for them in Xenopus spinal cord neurons in situ. To facilitate the comparison of times in culture to developmental stages, the age of cultured neurons was converted to an equivalent Nieuwkoop and Faber normal stage using data presented here on the effect of changing temperature on developmental rates of X. laevis. With the exception of the nonphosphorylated epitope of NF-H, which is indicative of the most mature axons found in situ. the emergence of the other neurofilament protein antibody epitopes closely paralleled that previously reported for these antibodies in situ. Thus, with respect to XNIF, NF-M, and NF-L, the neurities of cultured neurons were typical of young embryonic Xenopus laevis spinal cord axons. This system should prove useful for studying both the function of these neurofilament proteins during the early stages of axonal development and the dynamics of their transport. 1994 John Wiley & Sons, Inc.