大仓鼠年龄组及性别群体的遗传多样性

本文应用随机扩增多态性DNA (RAPD) 技术, 采用多态位点率、Shannon 信息多样性指数和Nei 遗传多样性指数作为种群遗传变异的指标, 研究了1998 和1999 年大仓鼠种群性别群体和年龄组群体的遗传多样性。主要的结论是: 性别群体间遗传分化较小, 年龄组群体间分化较大; 年龄组相距越大, 遗传分化也就越大; 幼年组的遗传多样性高于老龄组的遗传多样性; 1999 年秋季种群的年龄组遗传分化和差异要比1998 年四季种群更为明显。大仓鼠不同年龄组群体间的遗传分化支持遗传结构由于受时空上的选择压力而产生变异和适应性观点。大仓鼠幼体的遗传多样性比成体和老体的较高, 这一结果倾向于支持Ford 的假说, 说明种群繁殖出的幼体遗传多样性高, 其中有遗传质量好的, 也有遗传质量差的,但在生存过程中, 随着选择压力的作用, 种群趋于适应, 与环境不相适应的类型遭到淘汰,低质的幼体由于自然选择压力的增加而从种群中消失, 致使成年和老年群体多态性逐渐降低。     

大仓鼠的核型与B染色体研究

采用骨髓细胞染色体制片法,对分布于山东济南、泰山、东北长白山和陕西西安的大仓鼠的染色体组型、Ｇ－带、Ｃ－带和银染核型进行了分析研究。济南、西安和长白山的标本的二倍体数目和核型相似,２ｎ＝２８,２２ｔ＋４ｍ＋ＸＹ（ｓｔ,ｍ）。泰山标本的二倍体数目为２ｎ＝２８～２９,即在６７５％的中期相中多出了一条形态最小的端着丝粒染色体,这条染色体为Ｂ染色体,可能起源于Ｘ染色体。泰山标本的Ａ染色体组与上述３地标本相同。４地标本的Ｇ－带、Ｃ－带和银染核型相似。除Ｂ染色体外,每个端着丝粒染色体都具有着丝粒异染色质,ＡｇＮＯＲｓ较恒定地出现在Ｎｏｓ２,４,８,９,１３染色体上。也就是说大仓鼠的Ｂ染色体为Ｃ－带阴性,不携带核仁组织者。这种Ｂ染色体Ｃ－带阴性的特征在赤狐、黑家鼠和大林姬鼠朝鲜亚种中亦有报道。     

Stimulation as well as inhibition by antibiotics of the formation of GlcNAc-lipids of the dolichol pathway

The antiobiotics, diumycin, amphomycin, bacitracin, and showdomycin have been shown previously to block the synthesis of GlcNAc-P-P-dolichol and GlcNAc-GlcNAc-P-P-dolichol. In view of inconsistencies in the literature concerning the sites of inhibition, we have reinvestigated the influence of these drugs on the formation of these early intermediates of the dolichol pathway. Unexpectedly, when the individual products of the reactions were examined, instead of inhibition, showdomycin and bacitracin were found to stimulate the formation of GlcNAc-P-P-dolichol, and diumycin stimulated at low concentrations. Three derivatives of showdomycin were examined with similar results, showing stimulations of GlcNAc-P-P-dolichol formation of up to two-fold over controls. Amphomycin specifically inhibited GlcNAc-P-P-dolichol formation, an effect that was reversed by a high concentration of dolichyl phosphate. In contrast, with the exception of amphomycin, each compound directly inhibited the formation of GlcNAc-GlcNAc-P-P-dolichol. Using chemically synthesized GlcNAc-P-P-dolichol as substrate, the kinetics of inhibition of GlcNAc-GlcNAc-P-P-dolichol formation by showdomycin, bacitracin and diumycin was examined. The apparent Ki values calculated from these studies indicated that showdomycin was the most active inhibitor. These findings provide a new understanding of the action of these compounds on the GlcNAc-transferases of the dolichol pathway. © 1998 Rapid Science Ltd     

大仓鼠肥满度的研究

本文依公式K=100W/L~3计算了大仓鼠肥满度。统计结果表明,雌性肥满度大于雄性肥满度。肥满度随年龄增长而减小。不同作物类型样地中大仓鼠的肥满度变化不明显。不同季节肥满度有一定的变化,主要与繁殖和气候有关。肥满度与种群密度之间不存在明显的对应关系。     

Jolly-Seber法对大仓鼠和黑线仓鼠种群若干参数的估算

本文利用Jolly-Seber法估算了1986和1988年河北省饶阳县大仓鼠和黑线仓鼠的种群大小、存留率等参数。结果表明,大仓鼠的存留率比黑线仓鼠小,而且和密度负相关。大仓鼠和黑线仓鼠对铁丝活捕笼均不存在非等捕性。该方法对大仓鼠和黑线仓鼠种群参数估计是可行的。     

北京地区大仓鼠种群繁殖生态研究

1983-1985年,作者在北京农田区研究了大仓鼠的种群生态。获得标本1101号(♀497,♂604),解剖、观察、测量、记录雌雄生殖系统的变化及繁殖特征。对大仓鼠的雌雄性比、平均胎仔数、怀孕率等作了分析。结果:春季出生的雌鼠,两个月左右即达性成熟,并参加繁殖,在7月以后出生的雌鼠当年不参加繁殖。越冬鼠一年可繁殖2-3次。在数量较高的1983年,性比(♂/♀)为1.33,平均胎仔数为9.24;数量次高的1984年,性比为1.20,平均胎仔数为9.29;数量较低的1985年,性比为0.95,平均胎仔数为9.94。在数量较低的年份,大仓鼠种群的各项繁殖指标均优于数量较高的年份。     

哈尔滨郊区人为鼠疫疫源地鼠类种群动态分析

根据黑龙江省哈尔滨市郊区人为鼠疫疫源地1952～1996 年达乌尔黄鼠密度监测资料,建立了黄鼠密度的自回归模型D_t=0.1374+1.130 2D_t-1-0.4754D_t-2+0.8033D_t-3-0.4680D_t-4 , 对1997～2000 年的密度进行了预测。1952～1980 年, 人工捕黄鼠率极为显著地影响黄鼠密度(P<0.001)。在该地区, 1982～1996年共捕啮齿动物6种, 其中黄鼠和大仓鼠为野外优势种, 褐家鼠为室内优势种, 其余为常见种。大仓鼠、黑线仓鼠、黑线姬鼠均与夜行鼠总捕获率正相关(P<0.01),逐步回归模型为总捕获率=0.5219+1.1733 大仓鼠+10312 黑线仓鼠+ 1.1273小家鼠+ 0.9242 褐家鼠(P<0.0001)。黄鼠密度与捕获率不相关(P>0.10)。     

雌二醇对大仓鼠胁腺抑制作用的研究

通过研究发现雌二醇对雌性大仓鼠(Cricetulus triton)胁腺的大小和分泌活动存在明显的抑制作用。利用生理手术, 形成3组不同内分泌状况的鼠: 卵巢切除(OF)、正常(IF)、和卵巢切除后又置入雌二醇硅胶管 (OEF) 的雌性大仓鼠; 经过放射免疫方法测定表明由OF、IF到OEF 鼠血液雌二醇的浓度显著增高(P <0.01), 胁腺的重量、长度、宽度和厚度也显著减小(P< 0.05或P <0.01); 利用气相色谱对胁腺分泌物的分析发现, 从OF、IF到OEF鼠的胁腺分泌物的种类逐渐减少 , 有些成分尽管在 3 组不同生理状况的鼠中都存在, 但含量依次明显减少。以上结果表明雌二醇不仅能够抑制胁腺大小的增长, 而且也抑制了胁腺的分泌活动,从而减少了胁腺分泌物或其中某些成分的分泌量。     

不同性别和年龄的大仓鼠对黄鼬气味的反应

将雌性成体和雌雄亚成体大仓鼠 (Cricetulustriton)长期 (4周 )暴露给过量的黄鼬 (Mustelasibirica)肛腺分泌物 ,观察其行为和生理状态的变化 ,并通过与我们以前有关黄鼬气味对成年雄鼠影响的研究结果进行比较 ,表明黄鼬气味对不同性别和不同年龄大仓鼠的胁迫效应和生殖抑制存在差异。发现黄鼬气味对雌性大仓鼠的影响较雄性小 ,对亚成体的影响较成体小 ,这与雌性和未成年动物对各种胁迫因素的反应更敏感的普遍现象相反。在成年鼠中 ,雌雄鼠的攻击行为都受到黄鼬气味的抑制 ;但天敌气味使雌性的胁腺膨大 ,对胁腺标记和肾上腺大小无影响 ;成年雄鼠的肾上腺膨大 ,胁腺萎缩 ,标记减少。在亚成体中 ,除了雄性胁腺受到抑制(与成年雄鼠相同 )外 ,雌雄鼠的肾上腺和雌性的胁腺未受影响。亚成体实验鼠的体重都比对照组低 ,但成年鼠的体重未受影响。另外 ,与以往对其它鼠类的研究结果一致 ,天敌气味并不影响成年鼠的生殖器官 ,却抑制了未成年雄鼠的附睾和未成年雌鼠的子宫。这些差异可能和生理基础的性二态以及可能面临的被捕食风险大小有关     

Kinship alters the effects of forced cohabitation on body weight,mate choice and fitness in the rat-like hamster Tscheskia triton

It has been documented that social isolation imparts deleterious effects on gregarious rodents species,but caging in group imparts such effects on solitary rodents. This study was attempted at examining how kinship to affect body weight,behavioral interaction,mate choice and fitness when we caged male and female rat-like hamsters Tscheskia triton in pair,a solitary species. We found that females paired with nonsibling males became heavier than the females paired with sibling males,but both agonistic and amicable behavior between paired males and females did not differ between sibling and nonsibling groups. This indicated that kinship might reduce females' obesity in response to forced cohabitation,and dissociation might exist between physiological and behavioral responses. Furthermore,binary choice tests revealed that social familiarity between either siblings or nonsiblings decreased their investigating time spent in opposite sex conspecific of cage mates and/or their scents as compared with those of nonmates,suggesting effects of social association on mate and kin selection of the hamsters. On the other side,both females and males caged in pair with siblings show a preference between unfamiliar siblings or their scents and the counterparts of nonsiblings after two month separation,indicating that the kin recognition of the hamsters might also rely on phenotype matching. In addition,cohabitation (or permanent presence of fathers) elicited a lower survival of pups in nonsibling pairs than sibling pairs,but did not affect litter size,suggesting that kinship affects fitness when housing male and female ratlike hamsters together. Therefore,inbreeding might be adapted for rare and endangered animals.