小毛足鼠繁殖生态研究

１９９１￣１９９５年每年４￣１０月的各月中旬,在内蒙古伊克昭盟达拉特旗沙地草场上,不同生态环境中共布放１０１８４５个夹日,捕获鼠６３２５只,其中小毛足鼠（Ｐｈｏｄｏｐｕｓ ｒｏｂｏｒｏｖｓｋｉｉ）２２１７只,占３５．０５％。根据胴体重划分成４个年龄组,５年总的性比为４９．６１％,接近１：１,无季节差异。雄性繁殖期为９个月（２￣１０月）,有年间差异。雌性繁殖力随着年龄的增长而增高,亚成年组、成年Ⅰ组     

浑善达克沙地小毛足鼠的食量与食性动态

采用夹捕取样法采集内蒙古浑善达克沙地各月份小毛足鼠的样本,根据对样本的颊囊与胃内容物的组成分析研究了浑善达克沙地小毛足鼠的食性及其季节动态。结果表明,该鼠主要取食植物种子,占其食物组成的85%以上,其余部分为昆虫与植物茎叶。通过对实验室内饲养的小毛足鼠日食量的测定表明,小毛足鼠的日食量(D)与体质量(M)关系可用数学表达式表示为D=1.422×lnM-1.780。结合其种群结构特征,可以计算出小毛足鼠日均消耗2g左右的植物种子。     

内蒙古草原小毛足鼠的活动性、代谢特征和体温的似昼夜节律

小毛足鼠(Phodopus roborovskii)是分布在内蒙古草原沙地的一种小型哺乳动物,关于其生物学和生态学特征,尤其是生理学特征还知之甚少。似昼夜节律是动物行为学和生理生态学中备受关注的一个领域。在室内条件下通过体内埋置无线电传感器连续监测小毛足鼠的体温、用自动监测系统连续监测活动性和TSE LabMaster呼吸代谢测定系统连续测定了其代谢率的昼夜节律性。结果发现:小毛足鼠在夜间的平均体温是(37.27±0.39)℃,昼间的平均体温是(36.11±0.18)℃;在夜间的平均代谢率是(4.65±1.10)mLO2·g-1·h-1,昼间的平均代谢率是(3.09±0.42)mLO2·g-1·h-1;在夜间的平均活动率为(237±145)次/0.1h,昼间的平均活动率为(38±5)次/0.1h。小毛足鼠的代谢率、活动性和体温的峰值相位主要集中在夜间,属典型的夜行性动物。实验结果从行为学特性和生理学特征等新的角度支持了野外观察小毛足鼠是夜行性动物的推断。综合活动性、代谢率和体温三方面同步变化的特征,为小毛足鼠的似昼夜节律变化提供了新的机理性解释。研究也表明小毛足鼠是研究野生动物似昼夜节律变化机理的好模型。     

大绒鼠消化道形态的季节变化

为探讨栖息于横断山地区大绒鼠(Eothenomys miletus)的消化道特征与环境之间的适应关系,对自然环境中大绒鼠消化道各项指标进行了测定.实验分别测定了不同季节大绒鼠胃、小肠、大肠、盲肠的长度,及其含内容物重、去内容物重、干组织重.结果表明,大绒鼠消化道特征存在季节性变化,随着温度降低、食物质量下降,大绒鼠的小肠、盲肠长度增加;各器官重量均在6月份最大;大绒鼠在低温、食物质量下降、繁殖等胁迫因子作用下,通过增加食物摄入、调节消化道形态来满足能量需求的增加,维持正常的生理机能.大绒鼠的消化道在不同季节中表现出的变化模式,与其低纬度高海拔、年平均温度较低的生存环境有关,从一方面反映了该物种在温度胁迫下的生存机制和适应对策.     

高原鼠兔地面活动观察

应用耳标法标记动物,用Sharp pc-1500计算器作为事件记录器,对高原鼠兔的地面活动进行了研究。寒冬,鼠兔的日活动为9小时,4月为11—12小时,夏季地面实际活动时间较短。夏季日活动明显地具有两个峰期;进出洞频次,1月,日进出洞20—30次,4月,雄体日进出洞97—161次;地面活动以取食为主,取食时间在草盛期远短于草返青和枯黄期;取食行为次数占全部洞外活动记录次数的44.5％。8月,日实际取食时间为200—240分钟。对行为格局的分析表明,幼体花费在坐、移动、自我修饰等非社会行为方面的时间明显多于成体。     

中国石龙子繁殖季节血浆性类固醇激素水平的变化

本文研究了中国石龙子繁殖季节中性腺变化与血浆性类固醇激素水平波动间的相互关系.结果表明雌性中国石龙子卵黄生成需要雌二醇(17β-estradiol,E2)的刺激.体现在卵巢重量于4月底至5月中旬间达峰值,血浆E2水平于3月底至最高值,此后显著回落,并于排卵前再次回升;血浆孕酮(progesterone,P)的生理功能在于输卵管卵的维持、促进胚胎发育和卵壳的形成.从3月中旬至4月底间,血浆P水平在基础值附近波动.5月中旬,随动物的排卵,血浆P水平迅速上升,至该月底达最高值,于产卵后迅速下降;E2随P的上升而下降,两者呈反向变动.雄性血浆睾酮(testosterone,T)水平与生精作用、维持攻击、求偶及交配行为密切相关.血浆T水平于动物出眠后呈现显著的上升趋势,并于4月中旬达峰值.5月中旬后,随睾丸的萎缩,血浆T水平也缓慢下降,至6月底达最低值.     

高原鼠冬季节性繁殖中的神经内分泌调控：Ⅱ.不同光制对光殖恢复的…

本项针野外捕获的成年雄性高原鼠兔分３组进行不同光制的饲养,以检验光周期对其神经内分泌－－生殖轴功能的影响：（１）长光照组睾丸及附属性腺的重量和血浆睾酮水平均明显高于自然光组（Ｐ＜０．０５）和短光照组（Ｐ＜０．０１）。（２）长光照组的松果腺重量（１．５±０．１毫克,ｎ＝１５）和褪黑激素含量（８９．７±５．８微微克／松果腺）,均显著低于其它两组。（３）自然兴和短光照组性腺的显著萌发表明,在高原鼠兔节性     

影响微小毛霉凝乳酶活力的因素

介绍影响微小毛霉凝乳酶活力的几个因素．该微小毛霉凝乳酶的最适ｐＨ在５．４～７．０范围;在ｐＨ２～７之间酶活保持稳定;凝乳酸最适温度在２５～７０℃,并随温度的增高酶活增大;６０℃处理１０ｍｉｎ酶活损失６８％,并随时间的延长酶活损失加大;Ｆｅ２＋、Ｍｇ２＋对酶有激活作用,Ｎａ＋、Ｃｕ２＋对酶有抑制作用。     

高原鼠兔季节性繁殖中的神经内分泌调控Ⅱ．不同光制对生殖恢复期的影响

本项研究将野外捕获的成年雄性高原鼠兔（Ｏｃｈｏｔｏｎａｃｕｒｚｏｎｉａｅ）分３组进行不同光制的饲养,以检验光周期对其神经内分泌─—生殖轴功能的影响：（１）长光照组睾丸及附属性腺的重量和血浆睾酮水平均明显高于自然光组（ｐ＜０．０５）和短光照组（ｐ＜０．０１）。（２）长光照组的松果腺重量（１．５±０．１毫克,ｎ＝１５）和褪黑激素含量（８９．７±５．８微微克／松果腺）,均显著低于其它两组。（３）自然光组和短光照组性腺的显著萌发表明,在高原鼠兔季节性繁殖的年周期中,其神经内分泌─—生殖轴对春分前短光照的抑制作用具有不应期。     

用荧光雄鼠成功繁殖荧光鼠

GFP转基因鼠在医学实验中应用较广,由于这种鼠全身所有的细胞都带荧光,可取这种鼠的细胞在体外做各种处理,然后回输照射鼠,可以在照射鼠体内跟踪这些细胞的转化与分布,因此荧光鼠有着广泛的用途.我们在只有荧光雄鼠的情况下,繁殖了荧光鼠后代.由于荧光鼠全身是黑毛,为了更好地区别杂交后的子代是否是荧光鼠,我们用白色的杂交鼠与荧光雄鼠杂交,结果所生的子代全部是黑毛,经过回交,得到的荧光鼠后代,外周血中GFP阳性细胞百分比达到了95.8％,达到了做照射鼠治疗的研究要求,现报道如下.     

Learned and spontaneous magnetosensitive behaviour in the Roborovski hamster (Phodopus roborovskii)

Sensing the geomagnetic field, called magnetoreception, might be a helpful tool for an animal to orientate and navigate in its environment. Although several rodent species are known to be magnetosensitive, detailed insights into this sensory ability are rare and the underlying mechanism in mammals is still unknown. The magnetic sense of the Djungarian hamster (Phodopus sungorus) expresses a learned behavioural pattern. Here, we report evidence for magnetoreception based on learned cues as well as spontaneous magnetosensitive behaviour in a closely related species, the Roborovski hamster (Phodopus roborovskii), for the first time. The hamsters learned to build their nests in specific magnetic directions (nest‐building assay) and spent spontaneously more time exploring a magnet compared to a sham (magnetic object assay). Furthermore, an influence of weak radio frequency magnetic fields was observed and is discussed with respect to magnetoreception mechanisms.     

内蒙古浑善达克沙地小毛足鼠的能量代谢和体温调节

为了解小毛足鼠对沙漠生境的适应特征,对其能量代谢和体温调节特征进行了测定。代谢率采用封闭式流体压力呼吸计测定,非颤抖性产热用皮下注射去甲肾上腺素诱导,能量摄入采用食物平衡法测定。结果显示:小毛足鼠的热中性区为25～33℃,平均体温为35 7±0 1℃,最小热传导率为0 21±0 01mlO2/g·h·℃,基础代谢率为2 61±0 04mlO2/g·h,最大非颤抖性产热为8 53±0 28mlO2/g·h,非颤抖性产热范围(最大非颤抖性产热与基础代谢率的比率)为3 3。基础代谢率和非颤抖性产热都高于以体重为基础的期望值,最小热传导接近期望值。小毛足鼠的摄入能为2 26±0 12kJ/g·d;消化能为2 18±0 13kJ/g·d;消化率为97±0 2%;可代谢能为2 13±0 12kJ/g·d;可代谢能效率为94±1 2%。这些结果表明小毛足鼠对沙地生境的适应特征是:基础代谢率较高,体温相对较低,最小热传导率与期望值相当,热中性区较宽,下临界温度较低;较高的最大非颤抖性产热和非颤抖性产热范围以及较高的食物消化效率。     

注射胸腺依赖和非胸腺依赖抗原雄性黑线毛足鼠的内分泌状态和气味吸引力

作者研究了胸腺依赖抗原 (SRBC) (羊红血细胞 ,sheepredbloodcells ,SRBC)和非胸腺依赖抗原 (细菌脂多糖 ,lipopolysaccharide ,LPS)的免疫活化对黑线毛足鼠气味信号和内分泌状态的影响。成年雄鼠注射SRBS5天后 ,其气味的性吸引力下降 ,这种结果伴随着粪便中睾酮含量的下降。SRBC处理后 ,雄性气味吸引力降低 ,这在体液免疫反应低的雄性个体中最明显。与SRBC的作用相反 ,注射LPS的雄性个体的气味吸引力增加 ,成熟雌性个体用于嗅闻嗅觉刺激上的时间差异与经LPS和盐处理过的雄鼠的粪便中睾酮浓度的差异呈正相关。作者讨论了这两种相反的嗅觉效应的适应性意义     

EP-1不育剂对黑线毛足鼠种群繁殖的影响

为检验EP-1 不育剂对野外鼠类的施用效果,2004 年在内蒙古锡林郭勒盟阿巴嘎旗白音图嘎800 hm² 草场进行了大田实验,并随后进行了逐月的夹线跟踪调查,分析了不育剂(EP-1) 对黑线毛足鼠种群繁殖的效应。结果表明,EP-1 不育剂对黑线毛足鼠种群繁殖的抑制效果良好,投药区与对照区相比,投药区黑线毛足鼠的子宫损伤率达到80% ,平均胎仔数下降到对照区的2 /3 水平,妊娠率也下降到对照区的20% 。但EP-1 不育剂对雄鼠睾丸下降率的作用不明显。一次性投放EP-1 不育剂,对黑线毛足鼠种群的繁殖作用时间可维持4 个月以上,基本可实现对整个繁殖期的控制成效,这可能与黑线毛足鼠具有储藏种子的习性,储藏药饵多次进食有关。     

Photoperiod-dependent changes in exocytotic activity in the hypophyseal pars tuberalis of the Djungarian hamster,Phodopus sungorus

The pars tuberalis of the hypophysis of the Djungarian hamster, Phodopus sungorus, was investigated with regard to secretory activity by applying the tannic acid-Ringer perfusion technique. Two groups were maintained under long photoperiods (16 h light: 8 h dark) or short photoperiods (8 h light: 16 h dark), respectively. Perfusion with tannic acid showed that specific pars tuberalis cells release some of their secretory granules as indicated by typical exocytotic figures. The percentage of cells displaying exocytotic activity was significantly higher in the pars tuberalis of hamsters kept under long photoperiods. The number of exocytotic figures per single cell was not increased. These results provide further evidence for a secretory activity of the pars tuberalis and support the hypothesis of its involvement as a mediator between photoperiodic stimuli and the endocrine system.     

Fine structural studies of the islets of Langerhans in the Djungarian hamster (Phodopus sungorus)

Summary A study of the pancreatic islets of Langerhans in the Djungarian hamster (Phodopus sungorus) was initiated by the observation that 98 percent of the animals of a recently established colony showed ketoacidosis soon after birth, about ten percent of which later developed persistent hyperglycemia. The islets are made up of a centrally located mass of insulin-producing B-cells surrounded by a peripheral rim of A-and D-cells. Most islets are richly supplied by unmyelinated nerve fibers which terminate on all three cell types with cholinergic synaptic endings. Early changes in islet fine structure due to ketosis comprise degranulation of A-cells combined with signs of crinophagia of -granules. After the manifestation of hyperglycemia, degranulation of B-cells is followed by deposition of glycogen which in the late phase of the diabetic syndrome forms large masses obscuring the regular cellular organelles. In six-to nine-month hyperglycemic animals degenerative changes are also observed in D-cells in the form of autophagic vacuoles.Dedicated to Professor Dr. Helmut Ferner, Vienna on the occasion of his 65th birthday     

Paternal responsiveness in biparental dwarf hamsters (Phodopus campbelli) does not require estradiol

Males of the biparental hamster species Phodopus campbelli act as midwives and are responsive to an experimentally displaced pup. Males also have peripheral estradiol concentrations that are similar to conspecific females. Castration reduces peripheral estradiol, yet does not affect paternal responsiveness despite the known role of estradiol in maternal behavior. Synthesis of estradiol within the central nervous system, however, might not be affected by castration. Males received implants of osmotic pumps containing the aromatase inhibitor letrozole to reduce both peripheral and central estradiol concentrations. Though estradiol was effectively reduced, it had no effect on paternal responsiveness or reproductive success. Neither testosterone nor aggression directed towards an intruder was altered. Results support the emerging conclusion that estradiol is not required for the exceptional paternal behavior of male P. campbelli.