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该文测序了湾鳄的线粒体基因组全序列,全长为16,917bp。湾鳄mtDNA结构与其他脊椎动物相似,由22个tRNA,2个rRNA和13个蛋白质编码基因及1个非编码的控制区(D-loop)所组成。除NADH6和tRNAGln、tRNAAla、tRNAAsn、tRNACys、tRNATyr、tRNASer(UCN)、tRNAGlu、tRNAPro在L-链上编码之外,其余基因均在H-链编码。基因排列顺序与已测序的鳄类一致,这显示了鳄类线粒体基因排列顺序上的保守性。但鳄类线粒体基因排列顺序与脊椎动物的典型排列方式相比,有较大的差异,尤其是tRNAPhe基因的重排、tRNASer-tRNAHis-tRNALeu基因族的排列方式等。湾鳄mtDNA和已测序的鳄类一样,缺失轻链复制起始点(OLR)。基于17种鳄mtDNA控制区保守区,采用PAUP4.0最大简约法(Maximumparsimony,MP)构建MP树,邻接法(Neighbor-joiningmethod,NJ)构建NJ树,结果显示:食鱼鳄(Gavialisgangeticus)和假食鱼鳄(Tomistomaschlegelii)聚为一支后再与鳄科(Crocodylidae)的其他物种形成姐妹群,这与基于食鱼鳄和假食鱼鳄的线粒体全序列的分析结果一致,支持将食鱼鳄并入鳄科的观点。结果还支持非洲窄吻鳄(Crocodyluscataphractus)与鳄属(Crocodylus)构成姐妹群,可以单独划分为属的观点。 相似文献
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湾鳄采食量活动性季节变化与环境温度的关系 总被引:3,自引:0,他引:3
湾鳄是外热动物,其采食量及活动规律受环境温度的影响极为明显,呈现苏醒期、发情期、产蛋繁殖期(盛食期),越冬准确期,越冬期等季节性周期现象。越冬期人工保温,是提高湾鳄成活率的关键。 相似文献
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埃及的木乃伊 ,被考古学家挖出研究的不下五万具。1851年 ,法国考古学家奥丘斯·马里埃在开罗近郊的地下 ,发掘出了一座巨大的陵墓。陵墓是用精工磨制的黑红相间的花岗岩砌成的。在数千斤重的石棺中 ,人们惊奇地看到一具牛的木乃伊卧在其中。大约5000年前 ,埃及人把努比亚野生猫和山猫杂交 ,得到了新变种。由于新种猫特别能吃老鼠 ,所以受到埃及人的保护和崇拜 ,在神殿里铸造了各种神态的青铜猫。猫死了 ,还要制成木乃伊 ,涂以香料 ,隆重下葬。1860年 ,在埃及的别尼哈桑发现了古埃及的猫的墓地 ,这里竟埋葬着18万只猫的木乃伊… 相似文献
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概述了鳄类动物的繁殖生物学特性。对在其它爬行动物中不多见,而在鳄类中普遍存在的亲体关怀行为和孵化温度决定后代性别的现象进行了阐述。并从生态学和进化论角度,对这些现象进行了讨论。 相似文献
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本文简介了分支系统学意义上的鳄型动物(CrocodylomorphaWalker.1970)的组成。首次应用分支系统学方法讨论了重庆西蜀鳄的系统发有关系。本文的结论否定了西蜀鳄和西贝鳄类系统关系相近的论点,并认为前者比后者要原始得多,它是Mesoeucrocodylia中最原始的代表之一。 相似文献
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五步蛇一般在 6~ 8月间产卵 ,但在贵州的一些山区 ,有在 8月下旬至 9月初产卵的现象 ,时值气温偏冷 ,给孵化工作带来一定的难度。笔者曾在野外观察到五步蛇的母蛇在洞穴附近既能避光线直射又有散射光反射到 ,既能避雨水又能通风的环境下产卵孵化 ;孵化时 ,母蛇盘伏在其卵上 ,以自身体能转化为热量 ,营造一个较理想的孵化环境。在此启示下 ,笔者于 1 999年 8月至 2 0 0 0年 9月在气温偏低的自然环境里 ,以人工方法分 3次孵化74个蛇卵 ,孵化率达 96 %以上 ,现介绍如下。1 材料准备 半熟农家肥 (牛粪和草料的混合物 )约 2 5 0 kg、1口陶缸… 相似文献
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荒漠沙蜥血糖浓度的昼夜变动及季节性变化 总被引:3,自引:0,他引:3
国内外对爬行动物蛇类血糖浓度的季节性变化研究已有许多报道(Carmichael等,1945;Coluson等,1953;Miller等,1958;Sidorkiewicz等,1974;王培潮,1983,1991;吴瑞敏等,1985),但对蜥蜴的此类研究很少,国外见于Dessauer(1970)等。荒漠沙蜥Phrynocephalusprzewalskii是我国特有的蜥蜴种类,是典型的外热动物,它的许多生理活动都受季节性变化的影响。血糖作为蜥蜴生理活动的重要能源,在昼夜节律和季节性节律活动中,有何… 相似文献
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应用高效液相色谱法(HPLC)-UV检测了不同季节荒漠沙蜥(Phrynocephalus przewalskii)松果体内褪黑激素的含量.结果显示,其高峰值发生在春季,为1 017±209 pg/pineal.低峰值出现在冬季(实验室内冬眠,2~4℃),为355±68.5 pg/pineal,秋季的含量(735±133.7 pg/pineal)高于夏季的含量(597±94.9 pg/pineal).表明荒漠沙蜥松果体褪黑激素含量呈现明显的年周期节律并与光周期和生殖周期的年节律基本相符. 相似文献
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Mirtha Lewis Claudio Campagna Marcela Uhart Charles Leo Ortiz 《Marine Mammal Science》2001,17(4):862-872
Blood samples were collected from 156 free-ranging southern elephant seals ( Mirounga leonina ) from Peninsula Valdes to study the variation in blood parameters related to ontogeny and the annual cycle. Samples ranged from newborn pups to adults. Interactions between age and sex showed different trends in ontogenetic changes of blood parameters (MANOVA, Wilkis' Lamb-da12,243 = 0.75, P < 0.01). The hematocrit (HCT) and hemoglobin concentration (HB) reached adult levels early in life. Weanlings had 14 % higher HCT than pups, and similar levels to juveniles and adults (HCT range = 46%-62 %). HB of males were below those of females from weaning (18.4 vs . 20.3 g/dl) to adulthood (19.8 vs . 22.3 g/dl). Red blood cell counts (RBC) did not change significantly from pups to juveniles (2.8–3.2 106 /μl), but varied for adults at different times of the annual cycle. Breeding females had higher RBC than molting females (3.1 vs. 2.4 106 /μl). Changes in blood parameters are related to the development of diving capabilities from pups to juveniles. Changes in adults were associated with different stages of the annual cycle, and these may be the result of the requirements imposed by pregnancy and fasting duration. 相似文献
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The annual variation of major nitrogen pools, phosphorus, carbon, ash, and thallus water content in relation to seasonal environmental changes was studied in two northern Spanish populations of the edible seaweed Palmaria palmata (Linnaeus) Kuntze. Observed patterns were investigated using Spearman rank order correlation coefficients. There were significant relationships between thallus nutrient content and nitrate and orthophosphate seawater concentration, irradiance, temperature, and wave force. The highest levels of total N and P and nitrogenous compounds were observed during autumn and winter because the thallus stored N‐ and P‐rich compounds in response to high nutrient seawater concentration when growth was limited by low light and temperature. Phycoerythrin and other proteins were the main N reserves. Thallus P content was higher in algae from the eutrophic site. During spring, reduced N and P thallus content and increased ash, water, and C content were observed in the growing fronds. N and P seawater concentrations were undetectable during summer when nutrient reserves were low and growth was reduced and eventually suppressed, suggesting nutrient limiting conditions. Palmaria palmata clearly could take advantage of elevated N and P concentrations to create storage reserves in winter to support early summer growth. This storage response reduced the dependence of algal nutrition on the external nutrient supply and supports the use of pulse fertilization to diminish summer nutrient limitation of cultured algae. 相似文献
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《Chronobiology international》2013,30(2):273-283
Leptin, from the Greek leptos, meaning thin (in reference to its ability to reduce body fat stores), is a hormone secreted primarily by adipocytes. At one time, leptin was portrayed as a potential means of combating obesity. Recently, leptin has been identified as a potent inhibitor of bone formation, acting through the central nervous system. Since numerous studies clearly show that bone remodeling is circadian rhythmic with peak activity during sleep, it is of interest to explore circadian variability in serum leptin. Accordingly, circadian characteristics of serum leptin were examined in 7 clinically healthy men and 4 obese men with type II diabetes. Blood samples were collected for 24h at 3h intervals beginning at 19:00. The dark (sleep) phase of the light-dark cycle extended from 22:30 to 06:30, with brief awakening for sampling at 01:00 and 04:00. Subjects consumed general hospital meals (2400 calories) at 16:30, 07:30, and 13:30. Serum leptin levels were determined by a R&D Systems enzyme immunoassay technique. Data were analyzed by linear least-squares estimation using the population multiple components method. A statistically significant (P <. 018) circadian rhythm modeled by a single 24h cosine curve characterized the data of each group. The 24h mean leptin level was statistically greater (P <. 001) in the obese diabetic men than in the healthy men (9.47 ± 0.66 ng/mL vs. 24.07 ± 1.71 ng/mL, respectively). Higher leptin levels occurred between midnight and roughly 02:30, and lowest leptin levels occurred between noon and the early afternoon. The phasing of this rhythm is similar to the circadian rhythm in bone remodeling previously described. Our results suggest the findings from a single morning blood sampling for leptin may be misleading since it may underestimate the mean 24h and peak concentrations of the hormone. (Chronobiology International, 18(2), 273–283, 2001) 相似文献
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渤海南部半滑舌鳎的食性及摄食的季节性变化 总被引:25,自引:0,他引:25
本文研究了渤海南部半滑鳎的食性及其摄食的季节性变化,胃食物分析结果表明,半滑舌鳎为底栖生物食性鱼类,以虾类,蟹类,双壳类及部分中下层小型鱼类为主要食物,兼食一些多毛类,头足类,腹足类,棘皮动物及海葵,半滑舌鳎终年摄食,其摄食强度的周年变化不大,半滑舌鳎常年捕食鲜明鼓虾,日本鼓虾,口虾蛄,隆线强蟹及泥古隆背蟹等。夏季加强捕食小刀蛏,凸壳肌蛤等双壳类,降春季外还捕食一些以虾虎鱼为主的中下层小型鱼类。 相似文献
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