短杆菌肽S与脂膜结合前后的H／D交换动力学的研究

短杆菌肽Ｓ（ＧＳ）是一个十肽分子（环－（Ｌ－Ｖａｌ－Ｌ－Ｏｒｎ－Ｌ－Ｌｅｕ－Ｄ－Ｐｈｅ－Ｌ－Ｐｒｏ）２）,是由两个β转角和两个β片层结构所构成［１］。ＧＳ的功能是通过破坏葛兰氏阴性菌的膜结构来完成其抗菌活性。迄今为止,人们对ＧＳ与膜结合特点的研究结果还不一致。Ｄａｔｅｍａｎ等人利用２Ｈ－ＮＭＲ,３１Ｐ－ＮＭＲ和ＤＳＣ等技术研究了ＧＳ与ＤＰＰＣ多层脂膜的相互作用,指出肽仅仅作用于膜表面［２］;而Ｈｉｇａｓｈｉｊｉｍａ等［３］及张凤立等用２Ｄ－ＮＭＲ的研究结果［４］表明,ＧＳ的疏水部分应插入膜内。蛋白质及多肽的Ｈ／Ｄ交换动力学受其分子内氢键,分子空间结构的致密度及其周边环境如膜环境［５］的影响。我们利用衰减全反射红外光谱（ＡＴＲ－ＦＴＩＲ）对与脂膜结合前后的短杆菌肽Ｓ的Ｈ／Ｄ交换动力学进行了研究,实验结果提示ＧＳ插入了脂膜双层。     

孢堆黑粉菌属三个新组合及中国黑粉菌补遗Ⅷ

本文报道了３个新组合种和３个中国新记录种。新组合是：广州孢堆黑粉菌［Ｓｐｏｒｉｓｏｒｉｕｍ ｃａｎｔｏｎｅｎｓｅ（Ｚｕｎｄｅｌ）Ｌ．Ｇｕｏ］香茅粒孢堆黑粉菌［Ｓｐｏｒｉｓｏｒｉｕｍ ｃｙｍｂｏｐｏｇｏｎｉｓ－ｄｉｓｔａｎｔｉｓ（Ｌｉｎｇ）Ｌ．Ｇｕｏ］和海南孢堆黑粉菌［Ｓｐｏｒｉｓｏｒｉｕｍ ｂａｉｎａｎａｅ（Ｚｕｎｄｅｌ）Ｌ．Ｇｕｏ］。中国新记录种为：中间黑粉菌（Ｕｓｔｉｌａｇｏ ｔａｎａｋａｅ     

《游蛇科锦蛇属（Elaphe Fitzinger）专著》［德］

《游蛇科锦蛇属（ＥｌａｐｈｅＦｉｔｚｉｎｇｅｒ）专著》［德］ＡＭＯＮＯＧＲＡＰＨＯＦＴＨＥＣＯＬＵＢＲＩＤＳＮＡＫＥＳＯＦＴＨＥＧＥＮＵＳＥＬＡＰＨＥＦＴＴＺＩＮＧＥＲＫｌａｕｓ．Ｄｉｅｔｅｒ＆ｈｏｂ著。德国印制,捷克ＫｏｅｌｔＺ勤ｉｅｎｎｄＣＤ刀ｂ...     

人食管鳞状上皮癌糖复合物表达的研究

凝集素可与其相对应的糖复合物特异性结合。在癌症形成过程中细胞表面经历着显著的变化,本文用十种生物素化凝集素即ＵＥＡ－Ｉ、ＲＣＡ－Ｉ、ＤＢＡ、ＰＳＡ、ＰＮＡ、ＢＳＬ、ＬＣＡ、ＷＧＡ、ＣｏｎＡ和ＳＢＡ作为探针,对正常食管上皮和食管鳞状上皮癌进行研究,以确定正常食管上皮和食管鳞状上皮癌中糖复合物的改变,结果发现,ＰＮＡ和ＰＳＡ在正常食管和食管鳞状上皮癌中均无反应,ＲＣＡ－Ｉ、ＤＢＡ、ＢＳＬ、ＬＣＡ、ＣｏｎＡ和ＳＢＡ受体在正常和癌组织中有着特征性变化,ＢＳＬ和ＤＢＡ在食管中无反应,ＬＣＡ、ＳＢＡ和ＲＣＡ－１正常食管和食管鳞状上皮癌中反应方式不同,ＣｏｎＡ和ＷＧＡ则在同一癌组织的不同部位都显示出不同的反应。尽管ＵＥＡ－Ｉ在正常食管和食管鳞状上皮癌均呈阳性反应,但似乎未表现出有意义的变化。上述结果提示食管癌的发生与含α－Ｄ－ＧａｌＮＡｃ（ＤＢＡ和ＳＢＡ）、β－Ｄ－Ｇａｌ／β－Ｎ－ａｃｅｔｙｌ－Ｄ－Ｇａｌａｃｔｏｓａｍｉｎｅ（ＲＣＡ－Ｉ）、α－Ｄ－Ｇｌｃ／α－Ｄ－Ｍａｎ（ＬＣＡ和ＣｏｎＡ）、［β－（１－４）－Ｄ－ＧｌｃＮＡｃ］２／ＮｅｕＮＡｃ（ＷＧＡ）和α－Ｄ－Ｇａｌ（ＢＳＬ）等的糖复合物的改变有较为密切的关系。     

粉防己碱对血管紧张素Ⅱ促进心肌成纤维细胞增殖的抑制作用

血管紧张素（ＡＮＧ）Ⅱ对新生大鼠无血清培养第二代心肌成纤维细胞（ＦＢ）具有剂量依赖性的促进增殖、ＤＮＡ和ＲＮＡ以及胶原合成的作用。ＡＮＧⅡ１０７ｍｏｌ／Ｌ浓度时,ＦＢ的［３Ｈ］胸腺嘧啶核苷（Ｔｈｙｍｉｄｉｎｅ）,［３Ｈ］尿嘧啶核苷（Ｕｒｉｄｉｎｅ）,［３Ｈ］脯氨酸（Ｐｒｏｌｉｎｅ）掺入较对照组分别增加１６７％,５８％,１７４％,此刺激作用可被特异性ＡＮＧⅡ受体拮抗剂阻断;粉防己碱预处理也可抑制ＡＮＧⅡ上述作用,且呈剂量依赖性。以上结果提示：ＡＮＧⅡ通过受体介导直接刺激心肌ＦＢ增殖和胶原合成,引起心肌纤维化;钙拮抗剂粉防己碱对ＡＮＧⅡ导致的心肌纤维化具有抑制作用。     

药物诱导后的人大肠癌细胞的[Ca^2＋]i的变化

采用荧光分光光度计法检测维甲酸（ＲＡ）、１,２５（ＯＨ）２ＶＤ３及佛波酯（ＰＭＡ）诱导ＣＣＬ２２９细胞分化后［Ｃａ２＋］ｉ变化,并观察内质网（ＥＲ）特异的Ｃａ２＋－ＡＴＰａｓｅ抑制剂Ｔｈａｐｓｉｇａｒｇｉｎ（ＴＧ）、ＩＰ３受体抑制剂Ｈｅｐａｒｉｎ对ＲＡ诱导［Ｃａ２＋］ｉ变化的影响,从而探讨ＲＡ诱导［Ｃａ２＋］ｉ变化与ＥＲ的关系。结果显示：ＲＡ和１,２５（ＯＨ）２ＶＤ３在数秒内引起［Ｃａ２＋］ｉ显著升高。在ＥＧＴＡ和Ｖｅｒａｐａｍｉｌ预处理细胞条件下,ＴＧ不能抑制ＲＡ引起Ｃａ２＋从细胞内钙池中外流,ＲＡ作用后ＴＧ仍能升高［Ｃａ２＋］ｉ。另外,Ｈｅｐａｒｉｎ也不能完全抑制ＲＡ升高［Ｃａ２＋］ｉ。提示ＲＡ诱导大肠癌细胞升高［Ｃａ２＋］ｉ可能通过ＥＲ上ＩＰ３敏感性和非敏感性钙池,亦可能细胞内存在除ＥＲ外对ＲＡ敏感的钙池。     

低氧对肺动脉内皮细胞PDGF—B链释放及平滑肌细胞生长的影响

应用蛋白ｄｏｔｂｌｏｔ技术检测了低氧内皮细胞条件培养液（ＨＥＣＣＭ）和常氧内皮细胞条件培养液（ＮＥＣＣＭ）内ＰＤＧＦ相对含量,并利用［３Ｈ］－ＴｄＲ掺入法和流式细胞术观察了ＨＥＣＣＭ和ＮＥＣＣＭ及加入特异ＰＤＧＦ抗体对肺动脉平滑肌细胞（ＰＡＳＭＣ）生长的影响。结果表明,ＨＥＣＣＭ中的ＰＤＧＦ含量明显高于ＮＥＣＣＭ;ＨＥＣＣＭ能明显增强ＰＡＳＭＣ内ＤＮＡ合成,促进ＰＡＳＭＣ从Ｇｏ／Ｇ１期进入Ｓ期;当预先加入ＰＤＧＦ－Ｂ链抗体时,则会明显地抑制ＨＥＣＣＭ对ＰＡＳＭＣ的ＤＮＡ合成,阻止ＰＡＳＭＣ从Ｇｏ／Ｇ１期进入Ｓ期。结果提示,低氧时ＰＡＳＭＣ增殖与肺动脉内皮细胞分泌释放ＰＤＧＦ增加有关     

乳酸脱氢酶C4的精子免疫荧光定位特性

用１４个抗小鼠ＬＤＨ－Ｃ４的单克隆抗体对小鼠、树鼯和人精子的ＬＤＨ－Ｃ４进行了间接免疫荧光定位。结果显示：不同的单抗可以结合到小鼠精子表面不同的位置，其中ＰＡ１（Ｋ０２１）在尾部，ＰＡ２（Ｋ０２２）、ＰＡ４和ＰＡ５（Ｋ０２３）在中段和尾部，ＳＭ１、ＳＭ２和ＰＧ２的中段，ＳＭ３和ＳＭ４在顶体，ＳＭ５在顶体和赤道板。人和树鼯精子表面的ＬＤＨ－Ｃ４也呈现类似的情况。这些研究表明精子表面的ＬＤＨ－Ｃ４呈现     

P物质在谷氨酸兴奋外侧下丘脑-穹窿周围区引起的升压反应中之作用

Ｐ物质（ＳＰ）能神经元及其轴突末梢和受体广泛分布于很多心血管中枢。外侧下丘脑含ＳＰ能神经元,外侧下丘脑投射的升压区内又存在ＳＰ能纤维及ＳＰ受体;因此本工作检验ＳＰ在外侧下丘脑升压反应中的作用。实验显示：（１）Ｌ－谷氨酸（Ｇｌｕ）兴奋外侧下丘脑的穹窿周围区（ＬＨ／ＰＦ）或将ＳＰ分别注入各ＬＨ投射区：蓝斑（ＬＣ）、臂旁核（ＮＰＢ）或中脑导水管周围灰质（ＰＡＧ）均引起升压反应;（２）［Ｄ－Ｐｒｏ２,Ｄ－Ｐｈｅ７,Ｄ－Ｔｒｐ９］－ＳＰ（ＳＰ拮抗剂）预先注入ＬＣ或ＰＡＧ可使Ｇｌｕ兴奋ＬＨ／ＰＦ引起的升压反应减小,而注入ＮＰＢ对该反应无明显影响;（３）双侧延髓头端腹外侧区（ＲＶＬ）分别用酚妥拉明、心得安或阿托品预处理也可明显削弱该反应。结合我们以往的实验结果：ＲＶＬ内的α－、β－、Ｍ－受体介导ＬＣ升压反应,α－和β－受体介导ＰＡＧ－升压反应;本工作显示ＬＨ／ＰＦ可通过其ＳＰ能投射纤维作用于ＬＣ－ＲＶＬ和ＰＡＧ－ＲＶＬ升压系统而实现其升压反应。     

有序差异显示:一种基因表达谱系统比较法

系统研究具有同一基因组的各种细胞群之间基因的差异表达谱十分重要。目前,研究基因差异表达的技术大致有ｍＲＮＡ差异显示［１］、ＲＤＡ［３］、ＳＳＨ［４、５］和ｃＤＮＡ阵列［６］等。近几年,还发展了一些研究基因差异表达谱系统的技术,如ＲＬＣＳ（ｒｅｓｔｒｉｃｔｉｏｎｌａｎｄ－ｍａｒｋｃＤＮＡｓｃａｎｎｉｎｇ）［８］、ＧＥＦ（ｇｅｎｅｅｘｐｒｅｓ－ｓｉｏｎｆｉｎｇｅｒｐｒｉｎｔｉｎｇ）［２］和ＲＮＡ指纹法［９］等。然而,这些技术或较为复杂,或灵敏度偏低。本文拟介绍一种有效的基因表达谱系统比较法——有序差…     

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.     

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     

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。