雄性山地麻晰选择体温、热耐受性及温度对食物同化和运动表现的影响

研究了捕自安徽宿州的成年雄性山地麻蜥（Eremias brenchleyi）选择体温、热耐受性、温度对食物同化和运动表现的影响。结果显示：①选择体温、临界高温和临界低温的平均值分别为33.7、43.6和3.3℃。②环境温度在26－38℃时,对山地麻蜥食物通过时间、摄食量、表观消化系数（ADC）、同化效率（AE）和运动表现有显著的影响;在26－30℃时食物通过时间随温度升高而缩短,通过30℃则随温度升高而延长;在26和28℃时,摄食量、ADC和AE均小于更高温度的对应值。③体温在19－34℃,蜥蜴的疾跑速随体温上升而加快,31和34℃时最快,超过34℃后随体温升高而减慢;31和34℃时的持续运动距离最长,超过36℃后随体温升高而显著缩短,但体温19－36℃蜥蜴的持续运动距离无显著差异;19－34℃蜥蜴的路道停顿次数较少,无显著差异,超过34℃后显著增加。     

原尾蜥虎的选择体温、热耐受性和食物同化的热依赖性

(Tsel)、热耐受性和体温对食物同化的影响。Tsel无显著的日时间变化,两性个体的Tsel、临界低温(CTMin)和临界高温(CTMax)无显著的差异。Tsel、CTMin和CTMax的平均值分别为30.9℃、3.2℃和43.3℃。体温对动物食物通过时间有显著的影响。在25℃-33℃范围内,食物通过时间随体温升高而缩短;体温超过33℃后,食物通过时间随体温升高而延长。温度对原尾蜥虎的摄食量、表观消化系数(ADC)和同化效率(AE)有显著的影响。在25℃-37℃范围内,动物在低体温下(25℃和27℃)的摄食量、ADC和AE小于更高体温下动物的对应数值。种间比较结果显示,原尾蜥虎是生活于南方的蜥蜴中具有较强耐受极端体温的种类。     

热耐受性及温度对食物同化的影响

研究变色树蜥(Calotes versicolor)的选择体温、热耐受性、温度对食物同化的影响.结果显示:①幼体的选择体温、临界高温和临界低温的平均值分别为32.6、41.7℃和 7.7℃;成体的选择体温、临界高温和临界低温的平均值分别为33.1、42.0℃和8.2℃.②环境温度在26～34℃时,对变色树蜥食物通过时间和摄入能有显著的影响;对表观消化系数(ADC)和同化效率(AE)无显著的影响;在28～34℃时食物通过时间随温度升高而缩短;在26、28℃和30℃时,摄入能小于更高温度的对应值.     

华北丽斑麻蜥食物同化和疾跑速的热依赖性

作者研究山西阳泉丽斑麻蜥(Eremias argus)成体的选择体温、热耐受性及食物同化和疾跑速的热依赖性。选择体温、临界低温和临界高温无显著的两性差异,分别为36·0℃、1·0℃和44·9℃。在实验温度范围内,体温显著影响食物通过时间、日摄食量、日粪尿排量、表观消化系数和同化效率。食物通过时间在26 -34℃范围内随体温升高而缩短,在更高的体温下则延长。蜥蜴在30、32、34和36℃体温下明显摄入较多的食物、排出明显较多的粪尿。34℃和36℃下的表观消化系数和同化效率大于其它更低或更高温度下的对应数值,但这两个变量未因体温变化而呈现清晰的规律性变化。疾跑速在18 -36℃范围内随体温升高而加快,在38℃体温下则减缓。36℃或附近体温最适合疾跑速。疾跑速最适体温接近蜥蜴的选择体温,表明蜥蜴疾跑速的最适温度可能与其选择体温密切相关[动物学报52 (2) : 256 -262 , 2006]。     

蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的(虫匽)蜓(Sphenomorphus indicus,头体长42.8～54.4mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43.9～57.3mm,n=10)幼体,研究温度(24～32℃)对(虫匽)蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响.结果显示,24～30℃范围内,(虫匽)蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变.(虫匽)蜓幼体30和32℃摄食量和生长小于24～28℃;24～30℃ADC、AE随温度升高而下降,但32℃时又升高.蓝尾石龙子幼体24～26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24～28℃ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快.结果表明,(虫匽)蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体.     

(虫匽)蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的(虫匽)蜓(Sphenomorphus indicus,头体长42.8～54.4mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43.9～57.3mm,n=10)幼体,研究温度(24～32℃)对(虫匽)蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响.结果显示,24～30℃范围内,(虫匽)蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变.(虫匽)蜓幼体:30和32℃摄食量和生长小于24～28℃;24～30℃ADC、AE随温度升高而下降,但32℃时又升高.蓝尾石龙子幼体:24～26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24～28℃ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快.结果表明,(虫匽)蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体.     

蝘蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的蝘蜓(Sphenomorphus indicus,头体长42．8～54．4mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43,9～57．3mm,n=10)幼体,研究温度(24～32℃)对蝘蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响。结果显示,24～30℃范围内,蝘蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变。蝘蜓幼体：30和32℃摄食量和生长小于24～28℃;24～30℃．ADC、AE随温度升高而下降,但32℃时又升高。蓝尾石龙子幼体：24～26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24～28℃ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快。结果表明,蝘蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体。     

蜓和蓝尾石龙子幼体食物同化的热依赖性

用采自安徽滁州琅琊山的蜓(Sphenomorphus indicus,头体长42.8-54.4 mm,n=12)和蓝尾石龙子(Eumeces elegans,头体长43.9-57.3 mm,n=10)幼体,研究温度(24-32℃)对蜓和蓝尾石龙子幼体食物通过时间、摄食量、表观消化系数(ADC)、同化效率(AE)和生长的影响。结果显示,24-30℃范围内,蜓和蓝尾石龙子幼体的食物通过时间随温度的升高而缩短,超过30℃则基本不变。蜓幼体：30和32℃摄食量和生长小于24-28℃;24-30℃ ADC、AE随温度升高而下降,但32℃时又升高。蓝尾石龙子幼体：24-26℃摄食量随温度升高而增加,26℃后随温度升高显著下降;24-28℃ ADC、AE大于30和32℃,呈现出随温度升高而下降的趋势;26℃生长最快。结果表明,蜓和蓝尾石龙子幼体的摄食和同化能力均低于相应的成体。     

青海沙蜥的热耐受性、选择体温及摄食和运动表现的热依赖性

研究了青海沙蜥(Phrynocephalus vlangalii)成体的选择体温、热耐受性及食物同化和运动表现的热依赖性。结果显示:选择体温、临界低温和临界高温无显著的两性差异,其平均值分别为33.3、0.9℃和46.9℃。在27-35℃实验温度范围内,体温显著影响日摄食量,表观消化系数(ADC)和同化效率(AE)无显著影响。停顿次数随着体温的升高而降低,至39℃时停顿次数最少,但与37℃和41℃处理下的停顿次数无显著差异。疾跑速在17-39℃范围内随体温升高而加快,在39℃体温下最快。体温大于39℃后速度减慢。在17-27℃体温范围内,随体温的升高持续运动距离无显著差异。持续运动距离在29-41℃体温下大于较低体温(17-27℃)下的测定值。     

温度对蜥蜴血红蛋白及血浆总蛋白浓度的影响

研究在不同实验温度下驯化的荒漠沙蜥（Ｐｈｒｙｎｏｃｅｐｈａｌｕｓ）和密点麻蜥（Ｅｒｅｍｉａｘ　ｍｕｌ－ｔｉｏｃｅｌｌａｔａ）的血红蛋白浓度、血浆总蛋白浓度以及血浆清蛋白与球蛋白比例的变化，结果表明；在５℃下驯化的两种蜥蜴的血红蛋白浓度都很低；而在１５℃～３０℃之间驯化的蜥蜴血红蛋白浓度较高且比较稳定；３５℃时蜥蜴的血红蛋白浓度则下降。在同温度下密点麻蜥的血红蛋白浓度高于荒漠沙蜥。同种蜥蜴中，雄性的血红蛋白浓度高于雌性。两种蜥蜴的血浆总蛋白浓度均随驯化温度的升高而增加；荒漠沙蜥在２５℃、密点麻蜥在２０℃～２５℃时，血浆清蛋白与球蛋白的比例基本相等，高于或低于此温度时，清蛋白的比例上升，球蛋白的比例则下降。     

Temperature, stability, and the hydrophobic interaction

Changes in free energy are normally used to track the effect of temperature on the stability of proteins and hydrophobic interactions. Use of this procedure on the aqueous solubility of hydrocarbons, a standard representation of the hydrophobic effect, leads to the conclusion that the hydrophobic effect increases in strength as the temperature is raised to approximately 140 degrees C. Acceptance of this interpretation leads to a number of far-reaching conclusions that are at variance with the original conception of the hydrophobic effect and add considerably to the complexity of interpretation. There are two legitimate thermodynamic functions that can be used to look at stability as a function of temperature: the standard Gibbs free energy change, deltaG degrees, and deltaG degrees/T. The latter is proportional to the log of the equilibrium constant and is sometimes called the Massieu-Planck function. Arguments are presented for using deltaG degrees/T rather than deltaG degrees for variations in stability with temperature. This makes a considerable difference in the interpretation of the hydrophobic interaction, but makes little change in the stability profile of proteins. Protein unfolding and the aqueous solubility of benzene are given as examples. The contrast between protein unfolding and the hydration of nonpolar molecules provides a rough estimate of the contribution of other factors that stabilize and destabilize protein structure.     

How Temperature,Pond-Drying,and Nutrients Influence Parasite Infection and Pathology

The rapid pace of environmental change is driving multi-faceted shifts in abiotic factors that influence parasite transmission. However, cumulative effects of these factors on wildlife diseases remain poorly understood. Here we used an information-theoretic approach to compare the relative influence of abiotic factors (temperature, diurnal temperature range, nutrients and pond-drying), on infection of snail and amphibian hosts by two trematode parasites (Ribeiroia ondatrae and Echinostoma spp.). A temperature shift from 20 to 25 °C was associated with an increase in infected snail prevalence of 10–20%, while overall snail densities declined by a factor of 6. Trematode infection abundance in frogs was best predicted by infected snail density, while Ribeiroia infection specifically also declined by half for each 10% reduction in pond perimeter, despite no effect of perimeter on the per snail release rate of cercariae. Both nutrient concentrations and Ribeiroia infection positively predicted amphibian deformities, potentially owing to reduced host tolerance or increased parasite virulence in more productive environments. For both parasites, temperature, pond-drying, and nutrients were influential at different points in the transmission cycle, highlighting the importance of detailed seasonal field studies that capture the importance of multiple drivers of infection dynamics and the mechanisms through which they operate.     

Host Range,Temperature Response,Survival, and Overwintering of Alternaria cirsinoxia

Alternaria cirsinoxia was evaluated for its host range, the influence of temperature on mycelial growth, and survival and overwintering on Canada thistle (Cirsium arvense) in Saskatchewan. With the exception of leafy spurge, the host range of A. cirsinoxia was limited to species within the Asteraceae. Canada thistle, safflower, and sunflower were most susceptible to A. cirsinoxia, the latter two being crop species of lesser importance in Saskatchewan. Mycelium of A. cirsinoxia grew best at a constant temperature of 25°C and in temperature cycles which alternated around a mean of 20–25°C. Mycelium did not grow when exposed to constant temperatures of 0, 40, or 45°C for 7 days. However, at 0°C, mycelium survived and was able to resume growth, whereas at 40 or 45°C, mycelium was killed. In the field, A. cirsinoxia produced viable conidia on senescent, basal Canada thistle leaves for at least 3–4 months after inoculation in 1998 and 1999. Sporulation tended to be higher in 1998 than in 1999, possibly favored by the warmer, drier, and sunnier conditions prevailing during July to mid-September in 1998. A. cirsinoxia also overwintered and produced viable conidia on infected Canada thistle leaves in the field, and at constant 4°C, when sampled from November 1998 until April 1999. Sporulation of leaves overwintering in the field was lowest in April 1999, probably due to inoculum degradation as a result of surface flooding in the plots. Clusters and chains of chlamydospores were abundant on overwintering leaf and stem debris of Canada thistle in field plots inoculated 10 months previously. A. cirsinoxia subsequently sporulated on this infected debris. Based on these host-range tests, the risks to major nontarget crop species in Saskatchewan should be minimal after the inundative application of A. cirsinoxia as a bioherbicide for Canada thistle. However, this pathogen appears able to persist and remain potentially infectious in the field for a prolonged period of time after inoculation. Hence, longevity and spread of A. cirsinoxia should be evaluated further to minimize the potential risks to susceptible minor crop species.     

Temperature,metabolic power and the evolution of endothermy

Endothermy has evolved at least twice, in the precursors to modern mammals and birds. The most widely accepted explanation for the evolution of endothermy has been selection for enhanced aerobic capacity. We review this hypothesis in the light of advances in our understanding of ATP generation by mitochondria and muscle performance. Together with the development of isotope‐based techniques for the measurement of metabolic rate in free‐ranging vertebrates these have confirmed the importance of aerobic scope in the evolution of endothermy: absolute aerobic scope, ATP generation by mitochondria and muscle power output are all strongly temperature‐dependent, indicating that there would have been significant improvement in whole‐organism locomotor ability with a warmer body. New data on mitochondrial ATP generation and proton leak suggest that the thermal physiology of mitochondria may differ between organisms of contrasting ecology and thermal flexibility. Together with recent biophysical modelling, this strengthens the long‐held view that endothermy originated in smaller, active eurythermal ectotherms living in a cool but variable thermal environment. We propose that rather than being a secondary consequence of the evolution of an enhanced aerobic scope, a warmer body was the means by which that enhanced aerobic scope was achieved. This modified hypothesis requires that the rise in metabolic rate and the insulation necessary to retain metabolic heat arose early in the lineages leading to birds and mammals. Large dinosaurs were warm, but were not endotherms, and the metabolic status of pterosaurs remains unresolved.     

Substrate Availability,pH, and Temperature Influence Methanogenesis and Mild Steel Corrosion

Solid deposits of corroded pipelines in the Niger Delta were analyzed both chemically and microbiologically. The addition of substrate, especially acetate, significantly stimulated the methane production ranging from 0.85 to 1.60 mmole compared with 0.65 mmole of the control. Acetotrophic and hydrogenotrophic methanogens had their optimal methane production and corrosion rate at pH 5.5. All three types of methanogens produced the most methane at 37°C. Methane production by methanogens correlated strongly with corrosion rate. Pyrosequencing surveys show dominance of acetotrophic, hydrogenotrophic, and methylotrophic methanogens in the samples with no significant presence of sulfate-reducing bacteria (SRB), most likely due to the presence of the biocide, tetrakis-hydroxymethyl phosphonium sulfate. Our study shows that methanogens were one possible cause of pipeline failures in samples from the Niger Delta without the syntrophic association with SRB.