Social ontogeny and behavioural diversity: consequences for Bighorn sheep Oris canadensis inhabiting desert and mountain environments

The development of social behaviour was studied in three natural populations of Bighorn sheep ( Ovis canadensis ). Individuals in all populations exhibited the same behavioural repertoires, but the utilization of specific behaviours among both infants and adults differed between populations. It was suggested that differences in the adult utilization of behaviour patterns result in part from behaviours used during infancy. In turn, the social and physical environments affected the development of subsequent behaviour patterns in sheep older than lambs.
Desert sheep (in southern California) used mounting behaviours often, presumably because they matured sexually at an early age. Sheep in a more northern environment (British Columbia) used different behaviour patterns more frequently perhaps as a consequence of interactions experienced in larger bands. Additionally, playful interactions were reduced due to physical hazards in the desert, but they were at least nine times as frequent in the northern study population. Play in large groups resulted in the utilization of more different kinds of behaviour patterns. These behavioural findings are interpreted ecologically as consequences of inhabiting environments that differ socially and physically.     

烟碱型乙酰胆碱受体在面神经支配的口轮匝肌和躯体神经支配的腓肠肌中的表达差异研究

目的:研究烟碱型乙酰胆碱受体在在面神经支配的口轮匝肌和躯体神经支配的腓肠肌运动终板处的表达差异及可能的原因。方法:分离SD大鼠的口轮匝肌和腓肠肌,通过免疫共沉淀技术计算口轮匝肌和腓肠肌肌肉特异性激酶(Muscle Specific Kinase,MuSK)的表达以及MuSK磷酸化水平。对MuSK的上游信号通路中能使其发生磷酸化的集聚蛋白Agrin、低密度脂蛋白受体相关蛋白4(low-density lipoprotein receptor-related protein 4,Lrp4)以及表皮生长因子家族受体ErbB2、ErbB3和ErbB4(epidermal growth factor receptor)免疫荧光染色,计算这两条不同通路中的蛋白在运动终板处的表达水平。结果:口轮匝肌中MuSK磷酸化水平显著高于腓肠肌(P<0.05)。口轮匝肌与腓肠肌的运动终板处的Agrin和Lrp4表达没有显著差异(P>0.05)。口轮匝肌ErbB2、ErbB3、ErbB4的表达显著高于其在腓肠肌运动终板处的表达(P<0.01)。结论:口轮匝肌和腓肠肌运动终板ErbB、ErbB3、ErbB4的差异表达造成MuSK磷酸化水平不同,可能是两种肌肉运动终板处烟碱型乙酰胆碱亚基表达量不同的原因。