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The calcium ion is specifically required for the action of melanophorestimulating hormone on melanosome dispersion within lizard (Anolis carolinensis) melanophores in vitro. The response to this hormone is directly related to the concentration of the Ca(2+) ion. Lithium, choline, rubidium, and cesium will replace the sodium and potassium of Ringer solution if Ca(2+) is present. Calcium ions are not required for melanosome dispersion itself, since theophylline or dibutyryl cyclic adenosine monophosphate reversibly darkens lizard skins in the absence of calcium. 相似文献
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Tail removal from dominant juvenile Uta stansburiana resulted in a decrease in social status in dyadic encounters. Most lizards were affected after removal of two-thirds of their tails. In some pairs, dominant lizards lost status after removal of one-third of their tails but regained dominance after the other member of the pair lost two-thirds of its tail. Tail loss in nature may impose a social handicap to successful home range acquisition and thereby increase risk of death. 相似文献
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PLIN基因多态性及其与绵羊尾形和屠宰性状的关联研究 总被引:1,自引:0,他引:1
为了探讨PLIN基因多态性及其对绵羊经济性状的影响,利用PCR-SSCP技术对2个绵羊品种96个个体PLIN基因的9个外显子进行多态性分析,并将检测到的不同基因型与尾形和屠宰性状进行关联分析。结果表明:外显子3、4、5、6和8存在多态。外显子4的BB型个体的相对尾脂重显著大于AA和AB型个体(P<0.05);外显子6的AA型个体的相对尾脂重显著大于AB和BB型个体(P<0.05);外显子5的不同基因型个体间尾宽差异极显著(P<0.01),且AA型个体的尾宽大于AB型个体。PLIN基因的多态性对绵羊脂肪沉积有一定影响,可作为影响肉质性状的候选基因,从分子水平上指导肉用绵羊的育种工作。 相似文献
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为了研究不同尾型绵羊生产性能、屠宰性能、肉品质和脂肪酸组成的差异,选择相同饲养管理水平下8月龄兰州大尾羊(Lanzhou fat-tailed sheep)、小尾寒羊(Small-tailed han sheep)、藏羊(Tibetan sheep)的羯羊各6只,测定生产性能后进行屠宰试验,检测尾部脂肪的脂肪酸组成,并将生产性能与屠宰性能指标进行相关性分析。结果表明:兰州大尾羊的体长、体高和尾型相关指标极显著高于小尾寒羊和藏羊,兰州大尾羊和藏羊的胸围、胸深、胸宽、尻宽显著高于小尾寒羊;兰州大尾羊的宰前活质量和胴体质量显著高于藏羊,极显著高于小尾寒羊;兰州大尾羊和藏羊的屠宰率比小尾寒羊分别极显著高出15.50%和15.62%,净肉质量和骨质量显著高于小尾寒羊;小尾寒羊肉的剪切力为(0.30±0.12)kg·f,极显著低于兰州大尾羊和藏羊。3种羊尾部脂肪中共检测到36种脂肪酸,小尾寒羊的饱和脂肪酸相对质量分数极显著高于兰州大尾羊和藏羊,不饱和脂肪酸相对质量分数极显著低于兰州大尾羊和藏羊。兰州大尾羊的体高与宰前活质量、眼肌面积呈极显著正相关,胸深与宰前活质量、胴体质量、净肉质量和眼肌面积呈显著正相关。3个品种羊宰前活质量与胴体质量、净肉质量等产肉力指标呈显著正相关。表明在相同舍饲营养水平下,3个品种羊生产和屠宰性能综合表现为:兰州大尾羊藏羊小尾寒羊,藏羊的肉质表现出失水率低、肉色深、剪切力大、熟肉率高等特点,兰州大尾羊的尾部脂肪营养价值最高。 相似文献
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The treatment of agricultural soils with CH(3)Br (MeBr) has been suggested to be a significant source of atmospheric MeBr which is involved in stratospheric ozone loss. A field fumigation experiment showed that, after 7 days, 34 percent of the applied MeBr had escaped into the atmosphere. The remaining 66 percent should have caused an increase in bromide in the soil; soil bromide increased by an amount equal to 70 percent of the applied MeBr, consistent with the flux measurements to within 4 percent. Comparison with an earlier experiment in which the escape of MeBr to the atmosphere was greater showed that higher soil pH, organic content and soil moisture, and deeper, more uniform injection of MeBr may in combination reduce the escape of MeBr. 相似文献
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为了探明杭州湾湿地植物碱蓬Suaedaeglauc0,南方碱蓬Suaed austrdis,芦苇Phragmites australis和野艾蒿Artemisia lavandulacfolia等各自生境土壤盐分高低是否和种子在盐分胁迫下的萌发能力相一致。试验比较了它们所在生境的土壤含盐量、pH值及含水率,测定了4种植物种子在不同质量浓度氯化钠(NaCl)(0~50g·L-1)溶液处理下的萌发率,并分析了土壤含盐量、pH值和含水率和20g·L-1氯化钠溶液处理的种子萌发率之间的相关性。结果表明,各物种生境土壤含盐量顺序是南方碱蓬〉碱蓬〉芦苇〉野艾蒿;土壤pH值为芦苇〉野艾蒿〉南方碱蓬和碱蓬:土壤含水率为碱蓬〉芦苇〉南方碱蓬〉野艾蒿。氯化钠溶液处理对4种种子萌发率都有显著影响,萌发率随盐分质量浓度增加而下降:同一盐分质量浓度下.萌发率高低顺序依次是碱蓬〉南方碱蓬〉芦苇〉野艾蒿。复水后氯化钠溶液处理的种子萌发率都显著提高.但不同物种萌发率高低顺序和复水前相同。相关分析表明.土壤含盐量和不同种子在20g·L-1氯化钠胁迫下的萌发率是显著相关的。这些结果表明,土壤含盐量是限制上述4种种子萌发的重要因素:4种植物的分布是和它们各自生境的盐分高低条件和种子在盐分胁迫条件下的萌发能力相关的。图2表2参17 相似文献
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The response of five species of crabs to simulated predator attack was examined. Two terrestrial species autotomized their chelipeds after the chelae were firmly attached to the predator. Selection for attack autotomy is balanced by selection for retention of the cheliped whenever the cheliped is important in social or maintenance functions. 相似文献
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Cutaneous water loss in reptiles 总被引:1,自引:0,他引:1
Cutaneous and respiratory evaporation were compared in five species of reptiles at 23 degrees C. There seemed to be a clear correlation between water loss and aridity of the animal's habitat, total evaporation from the desert lizard Sauromalus obesus being about 5 percent of that from the crocodilian Caiman sclerops. Cutaneous evaporation was the major avenue of water loss in all animals examined. This is contrary to the common belief that reptilian skin is practically impermeable to water. 相似文献
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刘云英 《农业图书情报学刊》2010,22(8):188-190
传统文献资源和数字资源在利用率上分别遵循着帕累托原则和长尾理论,在Web2.0时代,图书馆在资源和用户等方面都存在着明显的长尾现象,通过构建实体和虚拟相结合的馆藏文献模式,采用多种服务方式,在满足用户个性化需求的同时,实现资源利用率的最大化。 相似文献
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几种植物对城市尾水中重金属的去除效果研究 总被引:1,自引:0,他引:1
为了筛选适合吸收城市尾水中重金属的植物品种,研究了酸模(Rumex acetosa L.)、莎草(Cyperus glomeratus L.)和空心菜(Ipomiea aquatica Forsk)3种植物对城市尾水中重金属Zn、Cu、Pb和Cd的去除效果,并以酸模为材料,研究其对人工模拟重金属Cd和Pb污染水体的适应性。结果表明:酸模、莎草、空心菜3种植物对城市尾水中Zn、Cu、Cd、Pb的去除率分别为74.33%、60.43%、45.45%、36.43%,其中酸模对重金属的去除效果最好,其次是莎草和空心菜。酸模对尾水中Zn、Cu、Cd、Pb的去除率分别达到了86.63%、90.37%、76.81%、66.67%。Cd和Pb含量分别在0.5~2.0mg/L和0.2~0.4mg/L时酸模有较好的耐性。因此,酸模更适合于城市尾水中重金属的吸收修复,且对一定质量浓度Cd和Pb表现出较好的去除效果。 相似文献
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Sleep patterns of the monkey and brain serotonin concentration: effect of p-chlorophenylalanine 总被引:2,自引:0,他引:2
The amount of time that monkeys (Macaca mulatta) slept was reduced after they were given p-chlorophenylalanine, a selective depletor of serotonin in animal tissues. The time spent in the rapid eye movement stage of sleep was unchanged, but the time in other sleep stages decreased. Seven regions of the brain had a 31 to 46 percent decrease in serotonin content; the concentration of cerebellar serotonin increased by 44 percent. 相似文献
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X染色体60149273位点在脂尾(臀)和瘦尾绵羊品种中的多态性及其基因定位 总被引:1,自引:0,他引:1
【目的】研究绵羊X染色体60149273位点在不同沉脂尾型绵羊品种中的多态性,为解析绵羊尾脂沉积性状的遗传机制提供基础数据。【方法】首先,采用PCR-SSCP分型方法检测X染色体60149273位点在不同脂尾类型绵羊品种的多态性,并借助PCR产物直接测序的方法确认各基因型相应序列,利用卡方检验的方法检测各基因型分布在不同品种中的平衡性。其次,利用生物信息方法将该SNP定位与绵羊androgen receptor(AR),并使用电子克隆的方法克隆出绵羊AR全长编码序列。同时以阿勒泰羊臀部脂肪RNA为材料,采用RT-PCR的方克隆绵羊AR第3—8外显子序列,利用生物信息学方法分析序列同源性以及序列的物种进化保守性。【结果】①PCR-SSCP结果显示,在脂尾(臀)型绵羊品种阿勒泰羊和湖羊群体中X染色体60149273位点未检出多态性,GG基因型占100%;而瘦尾(臀)型绵羊品种中国美利奴和萨福克羊群体中则出现了多态性,GG基因型分别下降至10%和21%。②利用比较基因组学首次电子克隆出该SNP所属基因AR的全长编码区,并从阿勒泰羊臀脂mRNA中成功扩增羊源AR第3—8外显子片段,测序结果与电子克隆序列完全一致。③物种同源性比对进一步显示,AR在哺乳类动物中高度保守,哺乳动物各物种间同源性高达90%;进化树分析结果显示,牛、绵羊、海豚和猪等哺乳动物亲缘较近。【结论】首次发现绵羊AR第3内含子一处SNP在脂尾(臀)与瘦尾绵羊品种中存在较大差异,该SNP将可作为一个分子标记运用于低脂绵羊新品种的培育,同时该SNP所属AR也可作为一个重要候选功能基因应用于绵羊尾(臀)脂沉积分子机制的相关研究。 相似文献
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Population phenomena, which provide much of the underlying basis for the theoretical structure of island biogeography, have received little direct study. We determined a key population trait-survival-in the Bahamian lizard Anolis sagrei on islands with an experimentally introduced predatory lizard and on neighboring unmanipulated islands. On unmanipulated islands, survival declined with several variables, most notably vegetation height: The island with the shortest vegetation had nearly the highest survival recorded for any lizard. On islands with the introduced predator, which forages mostly on the ground, A. sagrei shifted to taller vegetation; unlike on unmanipulated islands, its survival was very low on islands with the shortest vegetation but was higher on the others. Thus, species introduction radically changed a resident species' relation of survival to a key island-biogeographical variable. 相似文献
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Arnon TI Xu Y Lo C Pham T An J Coughlin S Dorn GW Cyster JG 《Science (New York, N.Y.)》2011,333(6051):1898-1903
Lymphocytes egress from lymphoid organs in response to sphingosine-1-phosphate (S1P); minutes later they migrate from blood into tissue against the S1P gradient. The mechanisms facilitating cell movement against the gradient have not been defined. Here, we show that heterotrimeric guanine nucleotide-binding protein-coupled receptor kinase-2 (GRK2) functions in down-regulation of S1P receptor-1 (S1PR1) on blood-exposed lymphocytes. T and B cell movement from blood into lymph nodes is reduced in the absence of GRK2 but is restored in S1P-deficient mice. In the spleen, B cell movement between the blood-rich marginal zone and follicles is disrupted by GRK2 deficiency and by mutation of an S1PR1 desensitization motif. Moreover, delivery of systemic antigen into follicles is impaired. Thus, GRK2-dependent S1PR1 desensitization allows lymphocytes to escape circulatory fluids and migrate into lymphoid tissues. 相似文献
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就河南小尾寒羊的产肉性能和羊肉品质进行了分析研究。结果表明:河南小尾寒羊生长发育快,产肉性能好,肉质细嫩,肉味浓郁,6月龄的屠宰率较高。肌肉中的蛋白质含量较高,氨基酸含量丰富,其中的赖氨酸、异亮氨酸等达到或超过了标准蛋白质中的含量。 相似文献
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