Exposing males to female scent increases the cost of controlling <Emphasis Type="Italic">Salmonella</Emphasis> infection in wild house mice

Secondary sexual characters often provide indicators of a male’s resistance to infectious diseases to rivals and potential mates, but it is unclear why. It is often suggested that males honestly signal their health due to energetic and other physiological trade-offs between investing into secondary sexual traits vs resistance to infectious diseases. Our aim was to determine whether such a trade-off exists using wild-derived male house mice (Mus domesticus). We exposed male mice to female scent, a manipulation that induces elevations in testosterone concentration and the expression of a variety of testosterone-mediated secondary sexual traits, and tested whether this sexual stimulation impaired the males’ ability to resolve or cope with an experimental infection (Salmonella enterica). We kept the males on a controlled diet to prevent them from compensating by eating more food. We found that sexually stimulated males were able to control bacterial growth as effectively as sham-stimulated controls; however, to do so, they lost more body mass during infection compared to the controls. In contrast, we found no evidence that sexual stimulation reduced the body mass of uninfected male mice. These results indicate that males’ responses to female odor are not immunosuppressive per se, yet they increase the energetic costs of controlling infection. Our findings support the idea that there is a physiological trade-off between secondary sexual signaling vs resistance to infectious diseases and suggest that studies using only immunocompetence assays might fail to detect such energetic trade-offs. We dedicate this paper to the late Professor Chris Barnard who conducted pioneering research on this topic.     

PM2.5对小鼠和H9C2细胞心肌肥大相关因子mRNA表达的影响

用采自太原市4个不同季节的细颗粒物(PM_(2.5))对小鼠心肌细胞H9C2进行染毒后,采用荧光定量PCR技术检测心肌肥大相关因子ANP和TGF-β的mRNA水平.采用浓度分别为0、1、3、10μg·mL~(-1)的冬季PM_(2.5)处理H9C2细胞后,检测心肌肥大相关因子ANP、β-MHC、MMP2和MMP9的mRNA水平.之后分别选取4周龄、4月龄、10月龄C57BL/6雌性小鼠作为实验模型,采用咽后壁滴注的方法用3 mg·kg~(-1) PM_(2.5)暴露4周.采用苏木素-伊红染色(HE)对小鼠心脏组织病理切片进行观察,并检测ANP和β-MHC的mRNA水平.结果发现,与对照组相比,冬季PM_(2.5)诱导H9C2细胞中ANP和TGF-β的mRNA水平升高最为显著;其中,当冬季PM_(2.5)染毒浓度较高时可诱导ANP、β-MHC、MMP2和MMP9的mRNA水平均显著升高.经PM_(2.5)暴露4周后,幼年和老年小鼠心肌细胞核质比显著降低.老年小鼠心脏组织中ANP和β-MHC的mRNA表达水平显著上升.实验表明,冬季PM_(2.5)诱导心肌肥大标志物表达改变的效应要强于其他季节,且有一定的剂量效应关系,而老年小鼠对PM_(2.5)诱导的心肌肥大效应最为敏感.     

敌百虫致小鼠外周血淋巴细胞DNA-蛋白质交联作用研究

为探讨敌百虫致DNA-蛋白质交联作用,以昆明小鼠为受试动物,敌百虫按0、20、40、60 mg·kg^-1四个剂量水平,灌胃染毒小鼠两周。第五组以提取的正常小鼠外周血淋巴细胞经50 μmol·L^-1的H2O2处理为阳性对照组。采用经改进的彗星试验方法来检测染毒后外周血淋巴细胞DNA-蛋白质交联效应。结果表明,与空白组相比,各敌百虫染毒组都能引起DNA损伤作用(p<0.01)并引起一定程度的DNA-蛋白质交联效应,在较高浓度(40、60 mg·kg^-1）时DNA-蛋白质交联尤为明显,存在一定的潜在突变风险。     

羟基化多溴联苯醚(OH-PBDEs)在小鼠肝脏微粒体的体外代谢及对CYP450酶活性的影响

羟基化多溴联苯醚(OH-PBDEs)是一类具有内分泌干扰效应的酚类化合物,生物毒性要高于母体多溴联苯醚(PBDEs),研究OH-PBDEs的体外代谢行为对于理解其在生物体内的富集转化具有重要意义。以小鼠肝脏微粒体作为研究对象,考察了3-OH-BDE-47、5-OH-BDE-47、6-OH-BDE-47和2’-OH-BDE-68在小鼠肝脏中的体外代谢,并分别研究了浓度为0.1、0.2、0.4、0.6、1.0μmol·L-1条件下4种OH-PBDEs对细胞色素P450酶系中7-乙氧基香豆素-O-脱乙基酶(ECOD)、7-乙氧基异吩唑酮-O-脱乙基酶(EROD)和苯胺4-羟基化酶(ANH)活性的影响。结果表明,4种OH-PBDEs在小鼠肝脏微粒体中均能够快速代谢,代谢率分别为80%(3-OH-BDE-47)、42%(5-OH-BDE-47)、86%(6-OH-BDE-47)和63%(2’-OH-BDE-68)。实验所设OH-PBDEs各浓度对微粒体的ECOD活性无显著性抑制作用,但对EROD的活性均表现出相同的显著抑制作用;4种OH-PBDEs表现出不同的ANH活性影响,即3-OH-BDE-47对ANH活性具有抑制作用,5-OH-BDE-47具有诱导作用,而6-OH-BDE-47和2’-OH-BDE-68对ANH活性无显著性影响。     

重组BALB/C鼠冷诱导RNA结合蛋白CIRP多克隆抗体的制备与鉴定

冷诱导RNA结合蛋白(CIRP)是第一种在哺乳动物细胞中被发现的冷休克蛋白,伴随着细胞冷应激过程过量表达.为进一步研究冷诱导RNA结合蛋白CIRP的生物学功能,构建重组BALB/C鼠CIRP的原核表达载体,重组BALB/C鼠CIRP蛋白经NI-NTA亲和树脂纯化后免疫獭兔制备抗CIRP多克隆抗体,以间接ELISA和Western blot检测抗体效价和抗原特异性.本实验成功构建了CIRP的原核表达载体,在E coli XL-1-blue得到了高效表达,利用原核表达包涵体蛋白免疫獭兔获得了高效价的CIRP多克隆抗体,该抗体能识别肝脏和睾丸中天然的CIRP蛋白.图5参14     

Varying levels of female promiscuity in four <Emphasis Type="Italic">Apodemus</Emphasis> mice species

Sexual selection in most vertebrates is based on the evolution of fitness optimization strategies such as multiple-male mating (MMM). Several ecological correlates of MMM have been identified in bird and fish populations; however, only few studies have documented the effects of environmental change on promiscuity in mammals. In this study, the 127 pregnant females from four central European and ecologically diverse species of field mice (genus Apodemus) were studied to assess the role of ecological factors that may have shaped the evolution of particular mating systems. MMM was found in all analyzed species: in Apodemus uralensis and Apodemus flavicollis, up to two males could be identified as the fathers of a particular litter, while three males sired 9.1% of analyzed litters of Apodemus sylvaticus and 20.6% of Apodemus agrarius. Furthermore, there were obvious differences between species in relative testes size and the proportion of multiple sired litters during those seasons when the opportunity for multiple mating was high. The species with the smallest testes and the least promiscuous was A. uralensis (only 43.5% of multiple sired litters), while the species with the biggest testes and the most promiscuous was A. agrarius (69.2%). MMM was significantly associated with higher litter size in A. flavicollis, and the probability of MMM strongly increased with season in A. agrarius and with abundance in A. uralensis. These results indicate that ecological factors are associated with MMM rates in Apodemus field mice and more research is needed to fully understand the evolution of mating strategies at different levels of biological resolution.     

五氯酚钠对雄性小鼠的生殖毒性作用

为研究五氯酚钠(PCP-Na)对雄性小鼠的生殖毒性作用,将100只昆明雄性小鼠随机分为5组:3个染毒组、1个阴性对照组(蒸馏水)和1个阳性对照组(环磷酰胺40mg·kg-1).以不同剂量(13.44、26.88、53.76mg·kg-1)PCP-Na经口染毒,连续染毒5d,每天1次.染毒结束后第2d和第23d分两批处死动物,检测精子数量、精子畸形率以及睾丸、附睾重量及其脏器系数的变化.结果表明,PCP-Na染毒结束后第2d,与阴性对照组相比,高剂量组(53.76mg·kg-1)精子畸形率显著增加(p<0.05),睾丸、附睾重量及附睾系数显著下降(p<0.05),其他指标无显著变化(p>0.05).中、低剂量组(26.88、13.44mg·kg-1)各检测指标与阴性对照组均无显著性差异(p>0.05);PCP-Na染毒结束后第23d,与阴性对照组相比,高剂量组(53.76mg·kg-1)精子畸形率显著增加、精子密度显著减少、睾丸和附睾重量显著下降(p<0.05),中剂量组(26.88mg·kg-1)附睾重量显著下降(p<0.05),其他指标均无显著变化(p>0.05);PCP-Na引起的精子畸形以头部畸形为主,主要为无定形,其次为无钩形、香蕉形和尾折叠.以上结果提示,在本实验条件下,PCP-Na对雄性小鼠具有明显的生殖毒性.     

聚苯乙烯微塑料对糖尿病小鼠肾脏的影响

以糖尿病小鼠为模式生物,探究了100nm和5μφ的聚苯乙烯微塑料(PSMPs)(200μg/L)通过饮水暴露28d后对小鼠肾脏的毒性.结果表明,糖尿病小鼠对PSMPs的暴露更加敏感,100nm和5μm PSMPs暴露导致糖尿病小鼠肾脏出现明显的炎性细胞浸润和淤血等病理损伤,且 100nm PSMPs对肾脏造成的病理损伤...     

Inhalation of two putative Gulf War toxins by mice

We employed our inhalation methodology to examine whether biomarkers of inflammation and oxidative stress would be produced in mice following inhalation of aerosols containing carbonaceous particles or the vapor of pesticides prevalent during the first Gulf War. Exposure to two putative Gulf War Illness toxins, fine airborne particles and the pesticide malathion, increased biomarkers of inflammation and oxidative stress in Friend virus B (FVB) female mice. Mice inhaling particles 24 h before had increased lung lavage and plasma Leukotriene B4 (LTB₄) (a biomarker of inflammation) and PGF_2α (a biomarker of oxidative stress) levels, lung lavage protein and lung lavage lactic dehydrogenase (LDH) levels. These changes were a function of particle density and exposure time. Compared to particle inhalation, mice inhaling malathion 24 h before had small increase in plasma LTB₄ and PGF_2α levels but no increase in lung lavage LTB₄, lung lavage protein, lung lavage LDH, and lung lavage alveolar macrophage (AM) levels compared to unexposed control mice. AM from particle-exposed mice contained phagocytosed particles, while AM from malathion-exposed mice showed no abnormalities. Our results indicate that inhaling particles or malathion can alter inflammatory and oxidative biomarkers in mice and raise the possibility that these toxins may have altered inflammation and oxidative stress biomarkers in Gulf War-exposed individuals.     

氰戊菊酯与辛硫磷混合杀虫剂(农满忆)对雄性小鼠精子畸形率和生殖细胞微核率的影响

为初步探讨氰戊菊酯与辛硫磷混合杀虫剂(农满忆)对雄性小鼠生殖细胞的损伤效应,将该杀虫剂对小鼠进行灌胃染毒5d,于第6d取小鼠睾丸细胞进行微核试验并采用精子畸形实验检测小鼠不同时期(第6、14、36d)精子畸形率的改变.结果表明,与对照组相比,该杀虫剂中、高剂量组(60、120mg·kg-1)小鼠睾丸细胞微核率均显著升高(p<0.05),而低剂量组(30mg·kg-1)微核率没有显著变化(p>0.05);中、高剂量组均能诱导小鼠不同时期精子畸形率显著升高(p<0.05),而低剂量组精子畸形率变化不显著(p>0.05).因此,氰戊菊酯与辛硫磷混合杀虫剂能够使雄性小鼠精子畸形率增加并造成雄性生殖细胞微核率升高,有一定的致突变作用.