细菌信号传导系统

细菌信号传导系统彭文涛,焦瑞身（中国科学院上海植物生理研究所上海２０００３２）细菌生活在易变的环境中,营养物水平、毒物水平、酸度、温度、克分子渗透压浓度、湿度等环境因子快速而不可预言地变化着,为了生存,细菌演化出高级的信号传导系统,引起对环境的适应性...     

大鼠脊髓运动诱发电位的起源及传导

运动诱发电位 (ｍｏｔｏｒｅｖｏｋｅｄｐｏｔｅｎｔｉａｌ,ＭＥＰ)已被广泛用于脊柱外科、神经科、眼科、五官科等临床领域 ,然而有关其信号来源及传导途径仍存在许多争议 ,焦点在于ＭＥＰ信号主要经哪些脊髓传导束下传 ,锥体系或者锥体外系 ?造成分歧的原因很多 ,可能与多种实验因素相关。为便于比较 ,我们采用通用的刺激和记录参数 ,严格控制各种实验条件 ,研究了 30只正常ＳＤ大鼠ＭＥＰ的起源及传导规律。1　材料与方法(1)动物麻醉及手术　成年雄性ＳＤ大鼠 30只 ,体重 2 5 0～ 30 0 ｇ。氯胺酮 (30ｍｇ/ｋｇ)麻醉 ,机械通气 ,股动、静…     

中枢外源性胃动素对大鼠脑干胃相关神经元电活动及胃运动的影响

用核团或侧脑室微量注射、微电极细胞外单位放电记录及清醒动物胃运动记录等方法,观察了大鼠下丘脑腹内侧区（ｖｅｎｔｒａｌ ｍｅｄｉａｌ ｈｙｐｏｔｈａｌａｍｕｓ,ＶＭＨ）或侧脑室内（ｉｃｖ）微量注入胃动素（ｍｏｔｉｌｉｎ）对延髓迷走复合体（ｄｏｒｓａｌ ｖａｇａｌ ｃｏｍｐｌｅｘ,ＤＶＣ）神经元电活动和胃运动的影响。结果表明：（１）ＶＭＨ注入胃动素会改变ＤＶＣ胃相关神经元的电活动;（２）ＶＭＨ及侧脑室     

二元系统与磷酸传递信号传导

二元系统是细菌的信号传导系统,可分为经典与非经典系统。经典系统占主导地位,由组氨酸蛋白激酶(HK)和反应调节蛋白(RR)两种蛋白组成,在特定位置上分别含有保守的组氨酸(His)和天门冬氨酸(Asp)残基,磷酸传递过程直接从HK到RR仅需一步即完成。而非经典系统需要多步骤磷酸接力传递过程(His-Asp-His-Asp),该系统除含有HK和RR两种成分外,还同时含有一个磷酸接受器结构域和一个含组氨酸的磷酸转移结构域(HPt)。二元系统在细菌的生命活动中起到举足轻重的作用,因为在脊椎动物中尚未发现二元系统的存在,因此,二元系统有可能成为抗微生物的靶点。     

苯丙胺类药物依赖与中枢胆碱能系统关系研究进展

苯丙胺类兴奋剂滥用可致强烈精神依赖,引起精神分裂症以及认知功能损害.研究认为中枢神经胆碱能系统参与药物依赖的调控,苯丙胺类兴奋剂依赖后导致了部分脑区乙酰胆碱释放水平、囊泡转运蛋白、胆碱能受体表达以及受体功能发生了适应性的改变,并与依赖行为的表达存在一定的关系;部分胆碱能受体抑制剂可干预依赖行为的表达.目前尚未有研究证实苯丙胺类兴奋剂对胆碱能神经元有直接损害作用.本文对苯丙胺类药物依赖与中枢胆碱能系统关系的研究进展作一综述.     

植物系统获得的抗病性和信号传导

植物在长期的进化过程中,需要不断地抵抗病原微生物的侵害。在这种长期相互影响的共进化过程中,植物逐渐形成一系列复杂而行之有效的保护机制来抵御病原微生物的侵染。在植物抵御病原微生物侵染的过程中,宿主植物的抗病基因（R）产物与病原微生物无毒基因（Avr）产物的...     

植物病原细菌的双组分传导系统

植物病原细菌的双组分传导系统何晨阳,饶军华,王金生（南京农业大学植保系南京２１００１４）病原细菌与寄主植物之间建立成功的寄生关系是一个动态的信息交流过程。病菌的双组分传导系统是对环境信号,尤其是植物特定成分以及有关条件的识别,并且能有效传递,改变基因...     

鲶鱼电感觉中枢对静止和运动偶极子电场的反应

在7尾鲶鱼所记录到的11个电感觉中枢神经元中,6个只对运动的偶极子电场有反应;4个对运动和静止的偶极子电场均有反应,但以前者反应最强;另一个神经元不仅对运动的偶极子电场,而且对运动的塑料棒也有反应。研究表明,鲶鱼的电感应中枢最适合于察觉移动的电场目标。     

耳大神经动作电位及其传导速度的测定

检测人体耳大神经动作电位,对鉴别脊髓神经节前和节后纤维的病变有重要意义。关于耳大神经动作电位的测定方法,国内尚未见诸报道。本文介绍一种耳大神经动作电位简便测定方法,并报告国人耳大神经传导速度的正常值及其影响因素,为临床应用提供生理基     

CF0质子传导对两光系统间光能分布的影响

用饱和闪光法测定类囊体中叶绿素荧光猝灭。观察到作用于质子通道ＣＦ０的氯化三苯基锡促进ｑＱ而降低ｑＥ,ＤＣＣＤ无此作用。在解联条件下或在高盐介质中ＴＰＴ对ｑＱ的促进作用消失;在Ｈ２Ｏ－ＰＤ０Ｘ或Ｈ２Ｏ－ＰＢＱ电子传递系统中此促进作用亦消失;用调制荧光法或低温荧光测定均表现ＴＰＴ增加了两光系统间光能分布的不平衡,有利于光能在ＰＳＩＩ的分布。     

二硫化碳染毒大白鼠运动神经传导速度的研究

用静式染毒室,以1 600-1 900mg/m~3浓度的CS_2将19只大白鼠染毒,每天6小时,每周六天,历时八周。用Fullerton法测定大白鼠坐骨神经MCV,染毒前为50.91+8.45m/s,染毒3周时,减慢到41.63+6.83m/s,相当于同期对照组的75.8％(P<0.001);停止染毒后,经过12周的恢复,达到51.60+9.92m/s,已恢复到染毒前水平。用Seppülüinen法测定大白鼠坐骨神经MCV,染毒前为25.51+3.72m/s,在染毒期间,仅有轻微减慢,停止染毒后的第7周,减慢到20.71+2.65m/s,相当于同期对照组的75.4％(P<0.001)。经过18周的恢复,达到24.43+3.54m/s,相当于同期对照组的88.1％(P<0.05)。 比较两种测定MCV的结果可看出,CS_2不仅能损伤脊髓前角细胞和轴突,还损伤运动终板和肌肉。 用标准MCV测定技术测定MCV对早期诊断CS_2神经病是个有用的指标。测定CS_2接触者的末端潜伏期,对了解治疗期间和恢复期间病人的情况也许是更有意义的。     

CIRCADIAN RHYTHM OF DOUBLE (RATE-PRESSURE) PRODUCT IN HEALTHY NORMOTENSIVE YOUNG SUBJECTS

The double product (DP), systolic blood pressure multiplied by heart rate, is a surrogate measure of myocardial oxygen demand and cardiac workload used increasingly today in medicine. The double product is more strongly correlated with left ventricular mass than the daily blood pressure mean. The purpose of this study was to describe the normative circadian pattern of the double product in healthy normotensive young adults. We studied 125 men and 75 women, 23.0 ± 3.3 (mean ± SD) years of age, without medical history of hypertension and 24h ambulatory systolic/diastolic blood pressure mean consistently below 135/85 mm Hg. Subjects underwent ambulatory blood pressure monitoring at 30-minute intervals for 48 consecutive hours once each season of the year, yielding 930 protocol-correct blood pressure and heart rate time series. Subjects maintained their usual routine of diurnal activity and nocturnal sleep and avoided use of over-the-counter and other medication. Circadian rhythmicity in the double product was established by population multiple-component analysis. The double product rose rapidly from the lowest value, attained 3h before awaking from sleep at night, to a markedly elevated level at the commencement of morning activity. The double product was highest in the afternoon, roughly 7h after the commencement of diurnal activity. In both men and women, the shape of the highamplitude circadian rhythm in the double product was best described by a complex model composed of three cosine curves having periods of 24h, 12h, and 6h. The 24h mean in the double product of 8092.51 ±42.76 (mean ±SD) in men was significantly lower than that of 8353.17 ±37.48 in women (P <.001). The circadian double amplitude of the rhythm was statistically significantly greater (P <.001) in men (50% of the 24h mean) than women (44% of the 24h mean). The double product did not differ between seasons in women, but it did in men (P =.017) due to reduced heart rate in summer. The circadian pattern of large amplitude in the double product and its gender differences must be taken into account when using this variable to assess cardiac workload, risk of left ventricular hypertrophy, and efficiency of antihypertensive therapy. (Chronobiology International, 18(3), 475–489, 2001)     

乙酰胆碱对蛇运动神经末梢离子通道活动的反馈调节

由研究乙酰胆碱受体激动剂和阻断剂的作用提出,在脊椎动物运动神经末梢存在着对乙酰胆碱（ＡＣｈ）释放的反馈调节。神经末梢的离了通道在递质释放中有重要作用。本文是利用周膜下记录技术。研究ＡＣｈ对蛇运动神经末梢离子通道调节作用的报告。（１）２ｍｍｏｌ／ＬＡＣｈ明显抑制依钙Ｋ流（ＩＫ,Ｃａ）此效应与３ｍｍｏｌ／ＬＴＥＡ的相似。由于ｎＡＣｈＲ激动剂尼古丁（２ｍｍｏｌ／Ｌ） 不影响Ｉｋ,ｆ和ＩＫ,Ｃdisplay stat     

中华竹鼠胃肠道内分泌细胞分布型的研究

本文用免疫组织化学方法（ＰＡＰ法）对１０种ＧＩＥＣ在中华竹鼠（Ｒｈｉｚｏｍｙｓｓｉｎｅｎｓｉｓ）１５个胃肠段中的分布作了观察和统计分析,以探讨中华竹鼠胃肠内分泌细胞与其特殊食性的适应关系．结果表明：中华竹鼠胃肠中可能至少有７种免疫反应活性内分泌细胞。与大熊猫相比,尽管都以竹类为主食,但由于取食行为不同,它们ＧＩＥＣ的分布型不尽相同．这些结果从一定程度上表明ＧＩＥＣ的分布不仅与食物组成相关。也可能与取食行为有关。     

白鱀豚额隆声衰减和声速的测量

本文用水浴法测试了白鱀豚额隆切片标本沿体轴方向的声压衰减系数和声速。实验表明额隆内有若干点声衰减为负值及零值、意味着声波沿这些点传输时、声压非但不减小反而增大了。再将这些点连接起来看、恰巧和从左、右鼻栓到头前部的水之间的声传输相一致、这两条途径看起来有点像小声道似的。     

大鼠下丘脑室旁核神经元对电刺激中脑中央灰质、内侧丘系的反应

本工作以玻璃微电极记录PVH神经元的单位放电。当用双极电极刺激CG和LM时,观察PVH神经元对刺激的反应。其中,刺激CG时,在284个PVH神经元中发生逆行反应的有4个单位,发生顺行反应的有47个单位。顺行反应分为两型:Ⅰ型对单刺激发生反应,Ⅱ型只对串刺激发生反应。刺激IIM时,未能观察到PVH神经元的反应。 实验结果表明,PVH与CG之间有双向连接,而PVH与LM之间在电生理学上未能证明有连接的存在。     

大鼠肺泡巨噬细胞的更新时间

在估算吸入放射性核索致肺巨噬细胞的剂量以及分析有害因子对它的损伤效应时,肺泡巨噬细胞的更新时间是重要的生物参数。本文用颈静脉点滴的方法给大鼠注入~3H-TdR,剂量为4.64×10~4Bq/g体重,在注入后1—41天期间分批活杀,用0.02％EDTA-PBS洗肺获取肺泡巨噬细胞,用放射自显影方法测定标记的肺泡巨噬细胞％。注入后1天标记细胞为5.1％,第5天达峰值8.4％,以后随时间延长,标记细胞％降低,到41天降至0.6％。标记细胞％与注入后时间之间的关系,可拟合二项指数函数,相关系数0.9990。56％的细胞更新一半的时间为0.9天,44％的细胞为14天。文内还就本实验得到的结果与国外报道的资料进行了比较与讨论。     

LABORATORY EVOLUTION OF LIFE-HISTORY TRAITS IN THE BEAN WEEVIL (ACANTHOSCELIDES OBTECTUS): THE EFFECTS OF SELECTION ON DEVELOPMENTAL TIME IN POPULATIONS WITH DIFFERENT PREVIOUS HISTORY

In this study we examined the direct and correlated responses for fast and slow preadult development time in three laboratory populations of the bean weevil (Acanthoscelides obtectus). The first population (“base,” B) has experienced laboratory conditions for more than 10 years; the second (“young,” Y) and the third (“old,” O) populations were selected for early and late reproduction, respectively, before the onset of the present experiments. All three populations are successfully selected for both fast and slow preadult development. The realized heritabilities are very similar in all populations, suggesting a similar level of the additive genetic variance for preadult development. We studied the correlated responses on the following life-history traits: egg-to-adult viability, wet body weight, early fecundity, late fecundity, total realized female fecundity, and adult longevity. All life-history traits examined here, except for the egg-to-adult viability, are affected by selection for preadult development in at least in one of the studied populations. In all three populations, beetles selected for slow preadult development are heavier and live longer than those from the fast-selected lines. The findings with respect to adult longevity are unexpected, because the control Y and O populations, selected for short- and long-lived beetles, respectively, do not show significant differences in preadult development. Thus, our results indicate that some kind of asymmetrical correlated responses occur for preadult development and adult longevity each time that direct selection has been imposed on one or the other of these two traits. In contrast to studies with Drosophila, it appears that for insect species that are aphagous as adults, selection for preadult development entails selection for alleles that also change the adult longevity, but that age-specific selection (applied in the Y and O populations) mostly affects the alleles that have no significant influence on the preadult development. Implications of these findings on the developmental and evolutionary theories of aging are also discussed.     

中国土壤原生动物新记录种：纤毛虫门：寡膜纲

该文报道了首次在中国土壤中鉴定到的、隶属于纤毛虫门寡膜纲的６种原生动物。这些种类是腐生拟康纤虫、刚毛胃纤虫、怪形钟虫、无规靴纤虫和旗康纤虫。     

切断外侧嗅束后嗅球中僧帽细胞内B－50（GAP－43）mRNA的表达

本工作用原位杂交方法研究大鼠嗅球中僧帽细胞（一种ＣＮＳ神经元）损伤后,Ｂ－５０（ＧＡＰ－４３）ｍＲＮＡ表达的变化。结果表明外侧嗅束切断,导致约４０％的僧帽细胞内Ｂ－５０ｍＲＮＡ表达显著增高。持续到损伤后１０ｄ,在损伤后４周已下降至对照水平。而外侧嗅束切断后,大量僧帽细胞逐渐退化。因此本文工作报道嗅球中部分僧帽细胞,具有应答损伤而致细胞内Ｂ－５０ｍＲＮＡ上升的能力。但这种反应并不伴随被切断的嗅束的再生。