MPEG－SOD对急性低氧下鼠左心功能的保护作用

单甲氧基聚乙二醇（ＭＰＥＧ）活化后与超氧化物歧化酶（ＳＯＤ）偶联,经纯化后得到ＭＰＥＧ－ＳＯＤ,鉴定其分子量约为７．０×１０５Ｄａｔｉｏｎ。其在血液循环中酶活性半衰期超过３０ｈ,远大于天然ＳＯＤ（６－１０ｍｉｎ）。ＳＤ雄性大鼠分三组．对照组（ｎ＝８．由股静脉注入０．２ｍｌ生理盐水）、ＮａｔｉｖｅＳＯＤ组（ｎ＝８,注以０．２ｍｌ生理盐水配的８００ＵＳＯＤ）和ＭＰＥＧ－ＳＯＤ组（ｎ＝９,注以８００ＵＭＰＥＧ－ＳＯＤ）。低氧前三组鼠的心率（ＨＲ）、左室内峰压（ＬＶＰ）、左室压微分（ＬＶ±ｄｐ／ｄｔｍａｘ）和股动脉压（ＡＰ）均无统计学差别。在模拟６０００—６５００ｍ高度急性低氧１．８．１４ｍｉｎ记录上述各项指标,结果如下：除ＨＲ外,ＮａｔｉｖｅＳＯＤ组与对照组各指标均无统计学差别,ＭＰＥＧ－ＳＯＤ组的各项指标均明显高于对照组。表明ＭＰＥＧ－ＳＯＤ对急性低氧导致的左心室力学指标的减弱有明显保护作用,提示超氧自由基（Ｏ２－）在急性低氧导致左心室功能损伤中起重要作用,即可能是由Ｏ２－及其衍生的其它自由基损害心肌细胞生物膜系统所致。     

DOCA—Salt高血压大鼠模型的一种简易制备方法：DOCA硅胶管皮下埋入法

用外径４ｍｍ,内径２．５０ｍｍ的硅胶管制成长２５ｍｍ,管内填入ＤＯＣＡ１００ｍｇ,管壁钻有１０一１４个直径约３００μｍ微孔的药管,埋入雄性ＳＤ大鼠（１４０±９ｇ）右下腹皮下,摘除一侧肾脏,术后喂１％盐水。埋管后３周即可形成高血压,埋管后８周大鼠的收缩压达２３．３±０．３７ｋＰａ。而ＤＯＣＡ皮下注射组大鼠（１０ｍｇ／周）术后５周形成高血压,术后１３周大鼠的收缩压达２３．３±０．６６ｋＰａ。两组升压曲线回归系数（１．２９５和０．６９２）之间的差异有极显著性意义（Ｐ＜０．００１）。对照鼠的收缩压一直保持在正常水平（１６±０．１６ｋＰａ）。与ＤＯＣＡ皮下注射法相比,皮下埋管法具有两个显著优点：（１）升压速率较快,升压幅度较大;（２）方法简便可靠,重复性好。     

豚鼠腹腔神经节细胞γ－氨基丁酸双相反应的药理学特性

在豚鼠腹腔神经节细胞,γ－氨基丁酸（ＧＡＢＡ）可诱发“去极化－超极化”的双相反应,去极化伴膜电阻减小,超极化伴膜电阻增大,这种反应在低钙高镁液中仍然存在。蝇蕈醇可模拟ＧＡＢＡ双相反应,但在诱发相同强度的去极化反应时,蝇蕈醇产生的超极化弱于ＧＡＢＡ。荷包牡丹碱（１００μｍｏｌ／Ｌ）和印防已毒素（１００—３００μｍｏｌ／Ｌ）能可逆地抑制ＧＡＢＡ诱发的双相反应。Ｂａｃｌｏｆｅｎ对神经节细胞的膜电位无明显影响。结果提示,ＧＡＢＡ双相反应的去极化相由ＧＡＢＡＡ／Ｃｌ－通道受体复合物介导,而超极化相很可能由不同于经典的ＧＡＢＡＡ受体,但其药理学行为又由与之十分相近的另一种ＧＡＢＡ受体介导。     

艾氏剂环氧化酶及细胞色素P－450对小菜蛾抗药性发展的影响

本文对室内长期饲养的小菜蛾（Ｐｌｕｔｅｌｌａ　ｘｙｌｏｓｔｅｌｌａ　Ｌ．）敏感品系和田间采集的抗性种群体内的艾氏剂平氧化酶及细胞色素Ｐ－４５０进行了比较研究。结果证明,艾氏剂环氧化酶在感性和抗性小菜蛾间存在着量及质的差异。抗性种群的艾氏剂环氧化酶的Ｖｍａｘ和Ｋｍ值分别为感性品系的５．４％和６．５倍。抗性种群的细胞色素Ｐ－４５０的含量是感性品系的１．１—１．３倍。艾氏剂环氧化酶在量上及质上的差异及细胞色素Ｐ－４５０含量的提高是导致小菜蛾抗药性发生与发展的重要机制之一。而且质的差异较之量的差异可能起着更为重要的作用．     

A Protein Extracted from Mouse Sperm That Plays an Important Role in Fertilization

ＡＰｒｏｔｅｉｎＥｘｔｒａｃｔｅｄｆｒｏｍＭｏｕｓｅＳｐｅｒｍＴｈａｔＰｌａｙｓａｎＩｍｐｏｒｔａｎｔＲｏｌｅｉｎＦｅｒｔｉｌｉｚａｔｉｏｎＺＨＵＡＮＧＤａ－ｚｈｏｎｇ;（庄大中）,ＺＨＡＮＧＴｉａｎ－ｙｉｎ（张天荫）,ＣＨＥＮＤａ－ｙｕａｎ;（陈大...     

Coordinated mRNA and Protein Expression of Human LAMP-1 in Induction of Melanogenesis After UV-B Exposure and Co-Transfection of Human Tyrosinase and TRP-1 cDNAs

In order to better understand the cascade of melanogenic events in melanocytes, this report has introduced our two recent approaches for the expression of melanogenesis/or melanosome-associated genes and encoded proteins in melanocytes (melanoma cells) after repeated exposure to UV -B and after cotransfection of two human genes, i.e., tyrosinase and tyrosinase-related protein-1 (TRP-1). Repeated exposure of UV B (2.5–5.0 mJ/cm²) caused not only upregulation of tyrosinase and TRP-1 genes but also coordinated increase in the gene and protein synthesis expression of Lamp-1 (lysosome-associated membrane protein-1). When COS-7 kidney cells and amelanotic melanoma (C32 and SKMEL-24) and melanotic melanoma (G361 and SK-MEL-23) cells were exposed to cotransfection of human tyrosinase and TRP-1 cDNAs, there was also an increased expression of Lamp-1 mRNA and protein along with tyrosinase activation and new melanin synthesis. Importantly, single transfectants of human tyrosinase cDNA revealed marked cellular degeneration, whereas this degeneration was not seen in single transfectants of TRP-1 cDNA or cotransfectants of human tyrosinase and TRP-1 cDNAs, indicating that TRP-1 prevented, along with Lamp-1, programmed death of melanocytes after transfection of tyrosinase gene. The coordinated expression of TRP-1 and Lamp-1 was further confirmed by antisense oligodeoxynucleotide hybridization experiment against Lamp-1 gene, showing the decreased expression of TRP-1 as identified by three different types of anti-TRP-1 monoclonal antibodies. We propose therefore that human tyrosinase and TRP-l, when activated or expressed together, will coordinate to upregulate the mRNA expression and protein synthesis of Lamp-1. The Lamp-1 molecules will, in turn, cover the inner surface of melanosomal membrane, together with TRP-1 molecules, thus protecting the melanosomal membrane from toxic melanin intermediates generated during melanogenesis in the presence of active tyrosinase. In contrast, the expression of other lysosome-related proteins, e.g., β-galactosidase and CD63 is not stimulated in new melanogenesis.     

A stage—specific protein factor binding to a CACCC motif in both human β—globin gene promoter and 5‘—HS2 region

The DNaseI hypersensitive site 2 (HS2) of human β-globin locus control region(LCR) is required for the high level expression of human β-globin genes.In the present study,a stage-specific protein factor (LPF-β) was identified in the nuclear extract prepared from mouse fetal liver at d 18 of gestation,which could bind to the HS2 region of human β-globin LCR.We also found that the shift band of LPF-β factor could be competed by human β-globin promoter.However,it couldn‘t be competed by human ε-globin promoter or by human ^Aγ-globin promoter.Furthermore,our data demonstrated that the binding-sequence of LPF-β factor is 5‘CACACCCTA 3‘,which is located at the HS2 region of β-LCR(from-10845 to-10853 bp)and human β-globin promoter(from-92 to -84 bp).We speculated that these regions containing the CACCC box in both the human β-globin promoter and HS2 might function as stage selector elements in the regulation of human β-globin switching and the LPF-β factor might be a stage-specific protein factor involved in the regulation of human β-globin gene expression.     

中国喀斯特地区微生物群落结构和功能的研究进展

频繁的人类生产活动使植被遭到破坏,造成基岩裸露的石漠化现象,严重制约了喀斯特地区自然和社会经济的发展,随着生态修复工程的大力开展,微生物群落的结构和功能在生态修复中逐渐受到重视,因为微生物作为喀斯特生态系统的重要组成部分,不仅在物质循环过程中起着重要作用,也在喀斯特生态系统修复中占有十分重要的地位。所以微生物群落结构和功能的研究可以作为衡量生态系统稳定性的重要指标。就中国喀斯特地区的典型植被恢复的不同阶段、成土过程、不同的土地利用方式、矿山修复过程以及不同水域中的微生物群落结构及功能等方面的研究状况进行系统梳理,结合实例综合论述喀斯特地区生态修复过程中微生物作用的研究进展,以期为喀斯特地区生态修复提供参考。