110 resultados para 305.235


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2006年10月28日凌晨3点,笔者在位于云南省新平县哀牢山的金山丫口鸟类环志站进行夜间鸟类环志工作时,用灯光诱捕到一只鹭科鸟类,经鉴定为海南(Gorsachius magnificus),为云南省鸟类物种新记录。形态特征:头和颊部黑褐色;枕部具黑褐色的延长羽冠;有明显的白色眼后条纹,颊纹白色;眼球外凸,黄绿色的眼睑向外伸出;眼先裸露皮肤呈黄绿色;喉白,中央有褐色条纹;颈侧棕色,前端有黑色条纹,前颈具褐白斑驳的条纹,后颈黑褐色;背部、翅和尾羽褐色;第一枚初级飞羽外栗红色;胸、腹部、尾下覆羽及翅下覆羽白色,杂有褐色斑纹;上嘴黑色,下嘴嘴基黄色,嘴端黑色;虹膜褐色(中国鸟类野外手册上记载的虹膜为黄色,MacKinnon et al,2000);跗黄绿色。雌性标本量度(g,mm)如下:体重563,全长565,嘴峰72,翅长305,尾长111,跗76。海南是中国的特有种鸟类,属国家Ⅱ级重点保护鸟类。分布于中国南方的少数地区,国外仅在越南东京有过一次记录(MacKinnon et al,2000),种群数量稀少,过去曾记录于安徽、浙江、福建(Cheng,1987)、海南、广西及广东(Gao et al,200...

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慢性应激对学习记忆功能的影响是神经科学的热点问题,在脑内,海马和前额叶是与学习记忆功能密切相关的重要脑区,也是应激易累及损伤的主要靶区。膜流动性的改变在神经细胞功能活动中起重要作用。为探讨慢性应激对大鼠空间学习记忆功能的影响及前脑皮层和海马突触体膜流动性的作用。采用多因素慢性应激动物模型,通过开场试验和Morris水迷宫测试大鼠行为及空间学习记忆能力;并且测定大鼠前脑皮层和海马突触体膜流动性和突触体内游离Ca2+浓度的变化。研究结果显示,与对照组相比,应激组大鼠在应激后即刻,在新异环境中的自发活动和探究行为显著降低(p<0.05,p<0.01),空间学习记忆能力明显下降(p<0.05,p<0.01);并且应激组大鼠前脑皮层和海马突触体膜流动性显著降低(p<0.05,p<0.01);而突触体内游离Ca2+浓度的显著增加(p<0.05,p<0.01)。停止应激后一周,应激大鼠的各项指标有所恢复,但仍未达到正常水平。研究结果提示,慢性应激引起大鼠明显的开场行为改变和空间学习记忆功能障碍,这些变化可能与突触体膜流动性和突触体内游离Ca2+浓度的变化密切相关。

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在减数分裂粗线期, 杂种水牛精母细胞中形成22条正常的常染色体SC, 一个 中着丝粒/亚中着丝粒/端着丝粒三价体和XY双价体。表明沼泽水牛和摩拉水牛 的染色体具有高度的同源性, 沼泽水牛1号染色体是由摩拉水牛4号、9 号染色体 串联易位而形成。图版2参12

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中国西南部的橙腹长吻松鼠应分为四个亚种。西藏东南部米什米山区、察隅和云南西北部高黎贡山一带的D.l.Subflavientris应为一有效亚种; 西藏南部聂拉木等地的橙腹长吻松鼠D.l. nielamuensis为新亚种, 它们有头骨小、体色浅等特点; 西藏南部雅鲁藏布江大拐弯以西的墨脱亚种D.l. motuoensis也为有效亚种; 南亚亚种D.l. garonum亦应有效。图1表5参9

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该文首次报道3种叶猴脊神经丛的组成, 并与其他灵长类作了比较研究. 结果表明: 颈丛由C_(1-4)组成, 多数标本不存在枕小神经和多数标本存在舌下袢; 臂丛由C_(4)-T_(2)组成,形成典型的三干三索结构, 后索形成两个神经袢; 腰骶丛由L_(2-7)和S_(1-2)组成, 存在屈股神经和耻坐股神经, 与猴超科共同特征相一致。

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贾第虫存在5种组蛋白, 其在两种不同性质电泳系统中的电泳行为与相应的小牛胸腺组蛋白有近似的对应关系。说明贾第虫的组蛋白已发生了分化, 并已初步形成了性质不同的几个组分, 从而在一定程度上支持核小体组蛋白在真核生物的原核祖先阶段就已产生了分化的假说。

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Ovulation in the Bactrian camel depends upon ovulation-inducing factors in the seminal plasma. The present study was conducted to isolate and purify the bioactive fractions from the seminal plasma of these camels. The seminal plasma was fractionated by anion-exchange chromatography, and six fractions were obtained. The bioactive potential of each fraction was estimated from its effect on rat pituitary tissue cultured in vitro and by the effect of an intramuscular injection of the fraction into female camels in vivo. Both the third fraction (F3) and the fifth fraction (F5) stimulated the release of LH in vitro and in vivo. In addition, female camels ovulated within 48 h after intramuscular injection of F3. However, neither F3 nor F5 had any significant effect on the secretion of FSH, either in vitro or in vivo. When F3 was further fractionated into four subfractions, the third subfraction (F3-3) still stimulated the in vitro release of LH, but not of FSH. An attempt to further purify the ovulation-inducing factors in F3-3 failed owing to the similarity of the molecular characters.