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41.
Olga Aksenova Maxim Vinarski Ivan Bolotov Alexander Kondakov Yulia Bespalaya Alyona Tomilova Inga Paltser Mikhail Gofarov 《Journal of Zoological Systematics and Evolutionary Research》2017,55(4):298-309
In this study, we re‐examine two species of freshwater gastropods of the genus Radix Montfort, 1810 (family Lymnaeidae), endemic to the geothermal springs in the Lake Baikal region in the southern part of eastern Siberia — Lymnaea (Radix) hakusyensis Kruglov et Starobogatov, 1989, and Lymnaea (Radix) thermobaicalica Kruglov et Starobogatov, 1989. The alleged species status of these endemics has been re‐assessed by means of an integrative approach combining molecular genetic taxonomy techniques with the traditional methods based on shell and soft body morphology. Phylogenetic reconstructions were made using both mitochondrial (COI) and nuclear (ITS2) DNA markers. We used topotypic samples of both species and specimens sampled from other sites around Lake Baikal. The results demonstrate that the two endemic species are only synonyms of a widespread Holarctic species, Radix auricularia (Linnaeus, 1758), and represent its intraspecific morph (ecotype) adapted to living in thermal springs. A new synonymy is proposed: Thermoradix Kruglov et Starobogatov, 1989 = Radix Montfort, 1810 (syn. n.). 相似文献
42.
《Archives of animal nutrition》2013,67(2-3):199-213
Beyond the energy requirement of maintenance, the assimilated energy, occurring in bioproducts, is linearly proportional to the intake of metabolizable energy in non‐underfed conditions. In contrast, resting metabolic rate is differing between individuals within a population of an animal species. As adaptability to changed environmental conditions may play a role, young bulls were exposed to thermoneutral (18°C) and low (4°C) ambient temperatures and were fed at two feeding levels (1.0 and 1.6 times energy requirement in maintenance) to produce metabolic rate differences, using the same animals, metabolic rate was altered by reducing the sympathetic outflow in each case. Expression of sulfonylurea receptors in circulating mononuclear leukocytes and cells from skeletal muscle (m. semitendinosus) was studied by flow cytom‐etry. Changes of metabolic rate at rest corresponded to the portion of cells with sulfonylurea receptors expression. The data from reducing the sympathetic outflow and those from sulfonylurea receptors expression are useful to explain metabolic rate differences among individuals of an animal population. 相似文献
43.
云南地区热泉中氨氧化菌丰度对环境条件的响应 总被引:2,自引:1,他引:2
【目的】研究热泉中的氨氧化菌对于理解全球氮循环作用至关重要,而人们对于热泉中环境条件对氨氧化菌丰度分布的影响还知之甚少。本研究旨在研究云南热泉中氨氧化菌的丰度以及热泉环境因子(例如:温度、氨浓度及pH等)对氨氧化菌丰度的影响。【方法】在所选取的热泉中,采集沉积物、菌席或泉华样品。使用RNA逆转录、定量聚合酶链式反应及荧光原位杂交等技术对样品中各微生物种群进行定量分析。【结果】所选取的热泉沉积物、菌席或泉华中微生物总量大约为108-109细胞/g。其中,氨氧化古菌(AOA)占样品中微生物总量的0.02-1.32%,而氨氧化细菌数量低于检测下限。地球化学参数和AOA相对丰度的相关性统计分析显示,氨氧化古菌相对丰度值与NH3、NO2-、NO3-浓度和温度等具有统计学意义上的相关性,而其与Fe2+和及盐度无统计学意义上的相关性。【结论】在所调查的热泉中,氨氧化微生物种群主要由AOA组成,AOA在热泉中的氨氧化生物地球化学过程中起着重要作用。热泉中多个环境因子一起控制着AOA丰度在不同热泉中的分布特征,而某些环境因子,如盐度-和Fe2+浓度,可能不是控制AOA分布特征的关键因素。 相似文献
44.
Séguy M Perret M 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2005,175(2):107-115
Microcebus murinus, a small nocturnal Malagasy primate, exhibits adaptive energy-saving strategies such as daily hypothermia and gregarious patterns during diurnal rest. To determine whether ambient temperature (Ta), food restriction and nest sharing can modify the daily body temperature (Tb) rhythm, Tb was recorded by telemetry during winter in six males exposed to different ambient temperatures (Ta=25, 20, 15°C) and/or to a total food restriction for 3 days depending on social condition (isolated versus pair-grouped). At 25°C, the daily rhythm of Tb was characterized by high Tb values during the night and lower values during the day. Exposure to cold significantly decreased minimal Tb values and lengthened the daily hypothermia. Under food restriction, minimal Tb values were also markedly lowered. The combination of food restriction and cold induced further increases in duration and depth of torpor bouts, minimal Tb reaching a level just above Ta. Although it influenced daily hypothermia less than environmental factors, nest sharing modified effects of cold and food restriction previously observed by lengthening duration of torpor but without increasing its depth. In response to external conditions, mouse lemurs may thus adjust their energy expenditures through daily modifications of both the duration and the depth of torpor. 相似文献
45.
Beverly K. Pierson 《Photosynthesis research》1994,41(1):7-15
A personal historic account is presented of the discovery of the anoxygenic filamentous bacteria of hot springs:Heliothrix oregonensis andChloroflexus aurantiacus. The later discoveries of marine and hypersaline forms are also described. 相似文献
46.
Astrid Kodric-Brown Chris Wilcox Jason G. Bragg James H. Brown 《Diversity & distributions》2007,13(6):789-798
Human activities affect even the most remote and best preserved places on Earth. One of those places is Dalhousie Springs, Witjira National Park, in the arid centre of Australia. In 2003 we resurveyed the fish communities in springs to document changes since an earlier survey in 1991. Over the 12 years there were 18 population extirpations and only two colonizations, so total occurrences of five native species in 30 springs decreased from 83 to 67 populations. One species, the endemic Dalhousie goby, Chlamydogobius gloveri , accounted for 12 of the 18 population extirpations. Each fish species tended to persist in springs larger than some threshold size. Extirpations were related to spring size, with smaller springs more readily loosing populations, and to major habitat changes, which included large increases in the tropical reed Phragmites and concomitant decreases in open water, disturbed habitats, and dissolved oxygen. Extirpations of fish populations can be attributed primarily to habitat changes associated with reduced disturbance and herbivory as a result of the removal of feral livestock. These changes highlight the keystone impacts of large mammals on habitats and biotas of desert springs, and should be considered in management practices and policy decisions. 相似文献
47.
热泉微生物是驱动热泉氮(N)循环的主导力量,开展热泉生态系统中驱动氮循环微生物种群构成及其与环境响应的研究,对于探索热泉中氮的生物地球化学循环、生命进化、生物修复等方面都具有重要的理论和应用价值。本文综合阐述了热泉生态系统驱动氮循环的功能微生物(如固氮菌、氨氧化菌、厌氧氨氧化菌、反硝化菌、异化硝酸盐还原菌)在系统发育学上的分布、功能基因的相对丰度、活性及其与环境因子(如温度、pH)的相关性等方面的研究现状和亟待解决的问题。并展望了热泉生境中驱动氮循环微生物未来的研究方向。 相似文献
48.
环境温度对爪鲵体温及能量代谢的影响 总被引:2,自引:0,他引:2
应用封闭式小动物能量代谢仪测定了爪鲵在6℃、10℃、15℃、20℃和25℃环境条件下的体温和能量代谢以及在极端环境中的耐受性,探讨环境温度对爪鲵体温及能量代谢的影响.结果表明:爪鲵体温与环境温度呈正相关,其直线回归方程为:Tb=0.6966 0.9518Ta,相关非常显著.爪鲵对极端环境温度的耐受力较弱,在32℃-35℃高温和-2℃到-6℃低温 环境中的致死体温(TbL50)分别为27.7℃±0.9165℃和2.85℃±0.1539℃.在环 境温度为6℃-25℃的范围内,爪鲵的能量代谢与环境温度呈指数回归相关,指数方程为MR=0 .7495e0.0408x,相关显著.其代谢水平随环境温度的升高而升高,不同于内热源动物的代谢特征,爪鲵的体温调节和能量代谢显示出外热源动物的特点 相似文献
49.
动物能量代谢相关的生理生态特征与其地理分布密切相关。为探讨温州地区迁徙鸟类小杓鹬(Numenius minutus)的代谢产热特征及体温调节,本文在环境温度(Ta)5.0~42.5℃范围内,测定了小杓鹬的代谢率(Rm,以单位时间耗氧量表示,ml/h)和体温,并计算不同环境温度的热传导。结果显示:在环境温度为5~35℃的范围内,小杓鹬的体温维持相对恒定,平均体温为(42.8±0.10)℃;热中性区为27.5~40.0℃;在热中性区温度范围内,代谢率即基础代谢率为(221.31±6.01)ml/h,是体重预期值的141%;环境温度在5.0~27.5℃范围内,代谢率与环境温度(Ta,℃)呈负相关,回归方程为Rm=587.10﹣11.78 Ta;在5.0~27.5℃的环境温度范围内,小杓鹬的热传导最低,平均为(0.11±0.00)ml/(g·h·℃),是体重预期值的212%;代谢预期比和热传导预期比的比值(F值)为1.21,表明该物种有较好的体温调节能力。小杓鹬具有较高的体温和基础代谢... 相似文献
50.
《Chronobiology international》2013,30(8):1647-1659
The aim of the study was to examine seasonal variability in monthly admissions for community-acquired pneumonia (CAP) in Taiwan. Our study sample comprised 477,541 pneumonia patients in Taiwan between 1998 and 2005, inclusive. Results showed a fairly consistent seasonal pattern of pneumonia admissions, regardless of sex and age, and for the groups combined. Seasonal trends showed a peak in hospitalizations from January through April, followed by a sharp decrease in May and a trough from August through October. The auto-regressive integrated moving average (ARIMA) test found significant seasonality for all age and sex groups and for the whole sample (all p?<?0.001). After adjusting for seasonality, month, and trends, the ARIMA regression models revealed that the monthly pneumonia admissions rate was significantly associated with ambient temperature, for the total sample, for female groups, and for the 65–74 and?≥75 age groups (all p?<?0.01). A 1°C decrease in ambient temperature was associated with roughly a 0.03 increase in monthly pneumonia admissions rate (per 10,000 people) for the entire sample. We conclude the monthly pneumonia admissions rate was significantly associated with seasonality, and was higher in periods with low ambient temperatures. (Author correspondence: henry11111@tmu.edu.tw) 相似文献