老年与青年小鼠慢性应激后抑郁样行为的观察

目的：探讨慢性应激后不同月龄小鼠抑郁样行为的变化,以及海马和前脑皮层胰岛素样神经营养因子-Ⅱ （IGF-Ⅱ）的作用。方法：昆明品系小白鼠3月龄（青年）和14月龄（老年）,随机分为青年对照组和青年应激组、老年对照组和老年应激组,每组12只、雌雄各半。多因素慢性应激21 d,建立抑郁小鼠模型。采用悬尾实验和蔗糖偏好实验评价小鼠的抑郁样行为;并且检测小鼠海马和前脑皮层IGF-Ⅱ的表达水平。结果：与青年对照组相比,老年对照组小鼠的累积不动时间明显增多（P<0.05）,蔗糖消耗度明显降低（P<0.05）,并且IGF-Ⅱ阳性神经元数目在海马CA1区、CA3区、齿状回（D G）和前脑皮层均明显减少（P<0.01或P<0.05）;慢性应激后,青年应激组小鼠的第一次静止不动时间、累积不动时间和蔗糖消耗度与其对照组比较均有显著性差异（P均<0.01）,IGF-Ⅱ阳性神经元数目在CA1、DG和前脑皮层均显著减少（P<0.05或P<0.01）;与老年对照组比较,老年应激组小鼠的第一次静止不动时间明显减少（P<0.05）、累积不动时间显著增加（P<0.0 5）和蔗糖消耗度明显减少（P<0.05）,海马CA1、CA3和DG区IGF-Ⅱ阳性神经元数目均显著减少（P <0.05或P<0.01）。结论：慢性应激后小鼠的抑郁样行为可能与海马和前脑皮层IGF-Ⅱ表达的下调密切相关。     

昆明小鼠学习记忆能力的年龄效应及其与海马突触囊泡蛋白的相关性

为了探讨昆明小鼠(Mus musculus)年龄相关性空间学习记忆能力改变及其与海马突触前囊泡蛋白1(synaptotagmin 1,SytⅠ)含量之间的关系。选取3个年龄段的昆明小鼠,①青年组:6月龄,28只;②中年组:11月龄,22只;③老年组:22月龄,17只。利用六臂辐射状水迷宫(RAWM)任务检测其空间学习记忆能力;制作组织微阵列,采用免疫组化技术检测SytⅠ在海马中的的表达;采用方差分析方法对六臂辐射状水迷宫实验参数和SytⅠ的相对含量进行统计学分析,使用Spearman秩相关检测这二者之间的相关性。结果发现,老年组昆明小鼠在学习期及记忆期的平均错误数及潜伏期均高于中年和青年鼠(P0.05),中年昆明小鼠与青年鼠之间的差异不显著(P0.05);老年组昆明小鼠在海马CA3区及齿状回(dentate gyrus,DG区)中SytⅠ的相对含量显著高于中年鼠和青年鼠(P0.05);昆明小鼠海马CA3、DG区SytⅠ的相对含量与学习期和记忆期的错误数及潜伏期均成正相关(P0.05)。由此推断,昆明小鼠可出现年龄相关性空间学习记忆能力降低,其海马CA3和DG的SytⅠ相对含量出现年龄相关性升高,海马SytⅠ升高可能与昆明小鼠年龄相关性空间学习记忆能力减退有关。     

锁阳乙酸乙酯提取物改善慢性应激小鼠认知功能障碍的神经保护机制

本实验以去卵巢后慢性应激模型,探究锁阳乙酸乙酯提取物(ECS)改善慢性应激小鼠认知功能障碍的神经保护机制。采用Morris水迷宫检测小鼠空间学习记忆能力,Western Blot检测海马组织突触蛋白中突触囊泡蛋白(synaptophysin,Syn)和突触后致密物(Postsynaptic density protein 95,PSD-95)表达量,通过海马组织形态学改变进一步证明ECS的神经保护作用。Morris水迷宫结果显示雌鼠锁阳乙酸乙酯组穿越平台次数增加(P0.01)。Western Blot结果显示,ECS可增加Syn(P0.05)与PSD-95(P0.05)蛋白表达量。HE染色结果显示ECS可减轻海马神经元损伤,改善海马CA1区锥体细胞形态。结果表明ECS能够增加去势后慢性应激小鼠突触蛋白中Syn与PSD-95的表达量,保护海马神经元,改善慢性应激所致学习记忆障碍。     

青年和老年小鼠脑糖原及其代谢的差异

目的:比较青年小鼠和老年小鼠不同脑区糖原及其代谢的差异,为后续相关研究奠定基础。方法:分别取雄性C57BL/6J青年小鼠(8周龄)和老年小鼠(18月龄)皮层、海马、纹状体三个脑区脑组织,通过糖原定量试剂盒检测糖原含量,通过Western Blot检测糖原代谢相关酶(包括糖原合成、糖原分解、葡萄糖转运、乳酸转运相关酶类)的表达水平。结果:与青年小鼠相比,老年小鼠皮层、纹状体糖原含量明显上升,但海马的糖原含量无明显变化。在糖原合成代谢的关键酶中,糖原合成酶在老年小鼠皮层、纹状体的表达水平明显升高,而海马区则无明显差异;糖原分支酶在老年小鼠皮层的表达水平有所下降,在海马和纹状体则无明显变化。在糖原分解代谢的关键酶中,老年小鼠的糖原磷酸化酶在皮层、海马和纹状体均明显升高,而糖原脱支酶在上述脑区则无明显变化。葡萄糖转运体1的表达水平在老年小鼠与青年小鼠各脑区无显著差异。在单羧酸转运体中,老年小鼠单羧酸转运体1在各脑区均明显上升,单羧酸转运体4在皮层明显升高,其余脑区则无明显差异。结论:老年小鼠脑内糖原含量总体上较青年小鼠高,老年小鼠脑糖原代谢通路相关酶的表达与青年小鼠存在明显差异,且不同脑区之间存在异质性。     

刺五加胶囊改善抑郁大鼠学习记忆能力及对海马BDNF 表达的影响

目的:探讨刺五加胶囊对抑郁大鼠学习记忆能力及对海马BDNF表达的影响。方法:SD大鼠随机分为正常组、模型组和刺五加胶囊低、中、高剂量组,21d慢性轻度不可预见性应激刺激法(CUMS)制备大鼠抑郁模型,对照组给予生理盐水1ml灌胃,刺五加胶囊低、中、高剂量组分别给予刺五加胶囊(200mg/kg,400mg/kg,800mg/kg)灌胃,取大鼠海马组织。分别采用Morris水迷宫法和免疫组织化学法观察大鼠大鼠学习记忆能力及对海马脑源性神经生长因子(BDNF)表达。结果:刺五加胶囊低剂量组能升高海马组织中BDNF的表达(P<0.05,P<0.01),降低大鼠逃避潜伏期(EL)时间,提高大鼠空间探索时间(SET)(P<0.05,P<0.01)。结论:刺五加胶囊能升高抑郁大鼠海马组织BDNF的表达,提升抑郁大鼠学习记忆能力。     

亚麻木酚素对2型糖尿病小鼠学习记忆的影响及其机制初探

目的:研究亚麻木酚素(Flax ligands,FL)对2型糖尿病模型小鼠空间学习记忆的影响及其初步机制。方法:雄性C57小鼠随机分为对照组(Con)、糖尿病模型组(DM)及亚麻木酚素治疗组(DM+FL),DM与DM+FL组给予高脂饮食加小剂量链脲佐菌素(Streptozotocin,STZ)诱导2型糖尿病模型,之后DM+FL组灌胃给予FL 10 mg/kg,每日一次,连续14天,Con与DM组给予等量生理盐水。通过新物体识别试验、Morris水迷宫试验检测小鼠的学习记忆能力,利用Western blot技术测定小鼠海马脑源性神经营养因子(BDNF)及谷酰胺AMPA受体845位磷酸化(pGluA1-Ser845)蛋白表达水平。结果:与Con组比较,DM组小鼠新物体识别指数显著下降(P<0.01),在Morris水迷宫中逃避潜伏期延长(P<0.05),在目的象限内徘徊时间减少(P<0.01);小鼠海马区BDNF和pGluA1-Ser845的蛋白表达水平均显著低于对照组(P<0.01)。与DM组相比,DM+FL组小鼠新物体识别指数显著提高(P<0.01),在Morris水迷宫中逃避潜伏期明显缩短(P<0.05),目的象限徘徊时间显著增多(P<0.05);小鼠海马区BDNF和pGluA1-Ser845的蛋白表达水平均显著升高(P<0.01)。结论:亚麻木酚素对2型糖尿病小鼠学习记忆有明确改善作用,增加海马BDNF和pGlu-A1-Ser845的表达可能是其潜在作用机制。     

有氧运动改善AD模型APP/PS1双转基因小鼠中枢神经元线粒体融合分裂动态平衡

线粒体融合分裂平衡是线粒体动力学的需要。本研究观察12周规律有氧运动对APP/PS1双转基因小鼠中枢神经元线粒体融合分裂动态平衡的影响。本研究采用3月龄雄性APP/PS1小鼠（AD模型）随机分为AD安静组（AS）、AD运动组（AE）,同月龄雄性C57BL/6J小鼠做正常对照组（CS）。AE组进行12周规律跑台运动,5 d/周,60 min/d。前10 min运动速度12 m/min,后50 min运动速度15 m/min,跑台坡度为0°。八臂迷宫实验检测小鼠工作记忆错误频率和参考记忆错误频率;Western印迹检测小鼠皮层、海马组织中线粒体分裂蛋白Drp1和Fis1的含量,以及Drp1的活性（p-Drp1-Ser616）、线粒体融合蛋白Mfn1、Mfn2、Opa1的表达水平;透射电镜观察皮层、海马线粒体形态结构、健康线粒体比率及线粒体平均直径。本研究证实AS组较CS组工作记忆错误频率显著提高（P<0.05）,12周有氧运动显著降低工作记忆错误频率（P<0.05）。AS组小鼠皮层Fis1蛋白和海马脑区Drp1、Fis1蛋白表达水平及皮层、海马脑区Drp1蛋白的活性增加（P<0.05）。而皮层Mfn1和海马Mfn1、Mfn2蛋白表达水平显著降低（P<0.05）。12周有氧运动显著减低Fis1、Drp1蛋白表达及Drp1蛋白的活性,提高Mfn1、Mfn2蛋白表达水平（P<0.05）。AS组小鼠皮层、海马线粒体多呈现球形,部分线粒体膜结构消失,线粒体嵴结构紊乱。且AS组较CS组小鼠健康线粒体比率降低、直径缩短。12周规律有氧运动可明显改善线粒体形态和结构,提高健康线粒体比率及直径。本研究提示,12周规律有氧运动可有效抑制皮层、海马脑区线粒体分裂蛋白Drp1和 Fis1的表达,降低Drp1的活性（p-Drp1-Ser616）,上调线粒体融合蛋白Mfn1、Mfn2的蛋白表达水平,改善线粒体形态和结构以促进线粒体质量控制,是有氧运动改善AD模型空间学习记忆能力的分子机制之一。     

海马Sirt1在高压氧预处理改善异氟醚诱导老龄小鼠认知功能障碍中的作用

摘要 目的：通过shRNA抑制沉默信息调节因子1（sirtuin 1,Sirt1）基因表达,研究Sirt1在高压氧预处理改善异氟醚（isoflurane,ISO）诱导小鼠认知功能障碍中的作用及其对小鼠海马BDNF、GDNF基因表达的影响。方法： 将64只C57雄性小鼠随机分为假手术组（Sham组）、高压氧组（HBO组）、异氟醚组（ISO组）、高压氧预处理+异氟醚组（HBO + ISO组）;以及对照组（NS组）、Sirt1抑制组（sh-Sirt1组）、对照+高压氧预处理组（NS + HBO组）和Sirt1抑制+高压氧预处理组（sh-Sirt1 + HBO组）,每组8只。经慢病毒转染以及ISO末次暴露24小时后进行认知功能测试（Morris水迷宫测试）,随后处死小鼠,利用实时荧光定量聚合酶链反应（RT-qPCR）检测海马BDNF和GDNF的mRNA表达情况。结果：（1）异氟醚可以导致明显的认知功能障碍,与Sham组相比,ISO组靶象限探索时间百分比显著减低（P<0.01）,ISO组小鼠海马BDNF和GDNF mRNA表达水平显著下降（P<0.01）。（2）高压氧预处理可以改善POCD小鼠的认知功能障碍,ISO + HBO组靶象限探索时间百分比显著高于ISO组（P<0.05）,ISO + HBO组小鼠海马BDNF（P<0.05）和GDNF（P<0.01）mRNA表达水平显著升高。（3）高压氧预处理可以显著增加POCD小鼠海马BDNF（P<0.01）和GDNF（P<0.05）mRNA表达水平,慢病毒介导shRNA靶向下调Sirt1可以逆转高压氧预处理对POCD小鼠海马BDNF（P<0.05）和GDNF（P<0.01）mRNA表达水平的改变。结论：高压氧预处理是治疗POCD的有效方法,Sirt1可能是POCD治疗的潜在分子靶点。     

耐力运动对增龄大鼠脑皮层突触可塑性的影响及相关调控机制*

目的:探讨规律性耐力运动对脑皮层增龄性老化适应性的作用与机制。方法:将三个不同年龄段的健康SPF级雄性Sprague-Dawley大鼠分为3月龄 (青年,n=20)、13月龄 (中年,n=24)和23月龄 (老年,n=24)组,每组又随机分为静息组和运动组;静息组三组静息,运动组三组实施10周递增负荷规律的中等强度耐力运动:运动方式为跑台运动(坡度0),运动强度从最大摄氧量(V·O2max) 60%～65%逐渐递增到70%～75%,运动时间为10周;取大鼠脑皮层,HE染色测试大鼠脑皮层增龄性形态学变化,检测BDNF和SOD的蛋白表达及突触素-1(SYN1)和CaMK IIα/AMPKα1/ mTOR通路等相关基因。结果:静息各组大鼠的脑皮层结构呈现年龄增龄性衰老变化,脑皮层SOD表达呈增龄性下降趋势,BDNF表达变化呈增龄性上升趋势,SYN1和CaMK IIα表达水平随增龄性趋势变化不大,AMPKα1和SirT2以及 IP3R、AKT1、mTOR mRNA表达水平随年龄变化呈现中年略上升而老年下降趋势;与静息各组大鼠相比,运动各组大鼠脑皮层神经细胞核排列紧密有序,显微镜下观察细胞核的数量明显增加,运动促进大鼠脑皮层SOD、BDNF和突触素SYN1表达水平增加,其中老年大鼠SOD、BDNF表达水平显著上调(P＜0.01),青年和老年大鼠SYN1表达水平显著上调(P＜0.05),运动上调中年和老年大鼠脑皮层CaMK IIα表达水平上调(P＜0.01),而对青年大鼠CaMK IIα表达水平却是下调(P＜0.01),运动可上调青年大鼠脑皮层的AMPKα1表达水平(P＜0.05),而对中年和老年大鼠AMPKα1的影响不显著,运动均可上调各年龄大鼠脑皮层的SirT2表达水平(P＜0.05),运动上调各年龄大鼠脑皮层的IP3R/AKT1/ mTOR表达水平,其中青年IP3R显著上调(P＜0.01),青年和中年mTOR显著上调(P＜0.01),老年mTOR也显著上调(P＜0.05)。结论:耐力运动通过上调BDNF的表达水平,调控CaMK IIα信号、激活AMPK信号通路和IP3R/AKT1/mTOR信号通路,改善脑皮层的突触可塑性。     

SOCS-3基因在Balb/c小鼠脑组织中的表达与脑不对称性

为探讨细胞因子信号传导抑制因子-3（suppresso of cytokine signaling-3, SOCS-3）在Balb/c小鼠皮层、海马、下丘脑中的表达及其与脑不对称性的关系.通过伸爪取食法将Balb/c小鼠分为左利组和右利组,取左、右侧皮层,左、右侧海马及下丘脑,以RT-PCR法间接测定SOCS-3 mRNA水平.结果表明：a.在左利鼠右侧皮层中,SOCS-3基因表达水平显著高于左侧皮层(P＜0.05);右利鼠左侧皮层SOCS-3表达显著高于左利鼠左侧皮层(P＜0.05).b.海马中SOCS-3表达：左利鼠右侧海马SOCS-3表达显著高于左侧海马(P＜0.05);右利鼠左侧海马SOCS-3表达显著高于左利鼠左侧海马(P＜0.05).c.右利鼠下丘脑中SOCS-3显著高于左利鼠(P＜0.05).上述研究结果提示,Balb/c小鼠脑中SOCS-3表达与脑不对称性有关.     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000