流溪河和潖江河从化段浮游植物群落结构研究

2007年9月至2008年9月对广州流溪河和琶江河从化段浮游植物进行周年调查,分析其种类组成、细胞数量、优势种类组成、种类多样性等群落结构特征及其季节变化。广州流溪河和琶江河从化段浮游植物种类丰富,共鉴定了隶属于90属的218种（包含变种和变型）,其中绿藻为优势种类,共31属92种,占总种类数的42.20%。浮游植物细胞数量的变化范围是5.1～2090×103cell/L之间,平均值为152×103cell/L,最高值出现在春季,最低值出现在夏季。多样性H’指数较高,各站平均值变化范围为1.03～4.22,丰富度的变化范围为1.00～7.83,均匀度变化范围为0.63～0.85。多样性指数的最高值都出现在夏季,最低值出现在冬季。     

超大型烟草突变株的生理生化特征和分子生物学鉴定

超大型烟草突变株再生植株高度是野生型的2．2倍,叶片数是野生型的3．3倍,呈现晚花发育特征;叶片气孔保卫细胞中叶绿体数是野生型的1．3倍,叶绿素a、b和叶绿素总量均高于野生型,可溶性蛋白质含量是野生型的1．18倍,过氧化物酶、细胞色素氧化酶同工酶电泳图谱上有一定差异;可溶性蛋白SDS-PAGE电泳图谱上比野生型少4条谱带;RAPD结果表明突变体在DNA水平上确实发生了变化,DDRT-PCR结果显示出两者在基因表达上有差异。突变株再生植株可以开花结实,植株高大、叶数多,晚花的特征可以稳定遗传。     

病理性瘢痕中主要氧化酶和抗氧化酶活性测定

采用化学比色法测定正常皮肤(8例)、增生性瘢痕(10例)及瘢痕疙瘩(10例)组织中黄嘌呤氧化酶(xanthine oxidase,XO)、铜锌超氧化物歧化酶(copper,zinc-superoxide dismutase,CuZn-SOD)、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase,GPX)活性以及丙二醛(malonaldehyde,MDA)含量.结果表明:与正常皮肤比较,病理性瘢痕中XO和CuZn-SOD活性增加、CAT活性降低(P<0.05)而GPX活性不变,CAT/CuZn-SOD和GPX/CuZn-SOD活性比率下降(P<0.05),同时MDA含量升高(P<0.05).增生性瘢痕、瘢痕疙瘩之间比较均无差异.上述结果表明,在病理性瘢痕中,氧化酶XO,抗氧化酶CuZn-SOD、CAT以及GPX的活性改变可能是引起活性氧水平升高的原因之一,在抗氧化剂选择上,CAT可能较为合理.     

Microbial infection and inflammation in the development of chronic lung disease of prematurity

Bronchopulmonary dysplasia or chronic lung disease of prematurity is a prolonged respiratory failure with multifactorial etiology in very low birth-weight neonates. This review summarizes current knowledge about the molecular mechanisms of different infections and inflammatory responses that are involved in the development of chronic lung disease of prematurity.     

家天牛的研究

家天牛Stromatium longicorne(Newman)亦名凿点天牛、长角栎天牛,俗称干木虫,是我国南方建筑木材的大害虫。国内对家天牛的研究,解放前嘉理思(J.L.Grecsitt)虽在海南岛采集了标本,但没有引起重视,中国经济昆虫志第一册(1959)描述了成虫形态,但作为幼树害虫。1966年我们在海南岛某部调查营房木材害虫时,才发现这种天牛为害建筑木材极为严重,比白蚁有过之而无不及。     

Expression of bioactive recombinant GSLL-39, a variant of human antimicrobial peptide LL-37, in Escherichia coli

The human cationic antimicrobial peptide hCAP-18/LL-37 is the unique cathelicidin identified in human to date. It has broad spectrum of antimicrobial activities and LPS-neutralizing activity and is involved in angiogenesis. Both purified and synthetic LL-37 or its derivatives were used in the study on LL-37. However, production of LL-37 in Escherichia coli has not been established. In this study, its precursor instead of the mature peptide was adopted for expression to avoid the lethal effect of recombinant LL-37 on host cells. A thrombin recognition site was introduced between the cathelin-like domain and LL-37 domain by overlap PCR to construct fragment encoding modified precursor (mhCAP-18) to facilitate the final release of the recombinant peptide. Then mhCAP-18 was fused in-frame to thioredoxin gene under the control of inducible T7 promoter to construct expression vector pET-mhCAP-18. The soluble form fusion protein was expressed in E. coli and purified by Chelating Sepharose column chromatography. Thrombin digestion of the fusion protein yielded recombinant GSLL-39, which was then purified by cation-exchange chromatography. Recombinant GSLL-39, which has two extra residues on its N-terminus when compared with its native counterpart, showed similar antimicrobial activities against both Gram-negative and Gram-positive bacteria.     

螺旋纤维床固定化生物反应器同时产酶降解壳聚糖的研究

采用多孔聚酯泡沫固定里氏木霉,在鼓泡柱固定化反应器中同时产酶降解壳聚糖。结果表明通过控制降解时间可以得到不同平均聚合度的降解产物。在28℃,pH4.8,通气量3vvm条件下,利用固定化反应器,在30d内连续进行10批同时产酶降解试验,结果发现壳聚糖酶活力和壳聚糖降解率能保持稳定。每批产生的壳聚糖酶活力平均达到0.15u/mL以上,壳聚糖平均降解率为73%。     

中国人扩张型心肌病与受磷蛋白基因关系的研究

受磷蛋白（phospholamban）是心肌收缩的一个重要调节因子,可抑制心肌肌浆网钙ATPase的活性、降低其对钙的亲和力。正常情况下,受磷蛋白可被不同的蛋白激酶磷酸化从而解除其肌浆网钙ATPase的抑制作用。国外两个DCM家系研究发现受磷蛋白基因突变与DCM的发生有关,研究目的旨在探讨中国人群心肌特异性受磷蛋白基因突变与特发性扩张型心肌病发病的关系。收集60例确诊的特发性扩张型心肌病患者临床资料,采集血样本并分离白细胞和提取基因组DNA。应用PCR扩增肌特异性受磷蛋白基因片段,经测序检测基因突变的存在。结果显示60例扩张型心肌病人受磷蛋白基因开放阅读框未发现突变,仅有两例患者出现阅读框3′部分非翻译区分别离终止密码153和173位单个碱基T的缺失。两例患者终止密码后非翻译区单个碱基T的缺失据分析并无实际意义。因此我们认为绝大部分中国人扩张型心肌病的发病可能与受磷蛋白基因突变无关。Abstract: Phospholamban (PLB) is a prominent regulator of myocardial contractility and a reversible inhibitor of the cardiac sarcoplasmic reticulum Ca2+ ATPase activity. In normal cardiac muscles, phospholamban can be phosphorylated at distinct sites by various protein kinases and release its inhibition to sarcoplasmic reticulum Ca2+ ATPase. The studies of pedigrees have shown dilated cardiomyopathy (DCM) is related with mutation of PLB. The aim of present study is to investigate the relationship between mutation of PLB gene and DCM. Sixty patients with idiotic DCM were enrolled in present study. The clinical data were collected, including clinical symptoms, ECG and echocardiography. Peripheral blood samples of all these subjects were collected to extract genome DNA. The fragments of PLB gene were amplified by PCR and PCR fragment sequencing was performed to study weather mutation of phospholamban gene exists. phospholamban gene did not show any mutation in these patients. Most Chinese DCM patients may not be related with mutation of PLB gene.     

在受重金属Zn2+胁迫的斜纹夜蛾幼虫寄主上双斑侧沟茧蜂的生存与发育

通过在植食性昆虫斜纹夜蛾Spodoptera litura Fabricius幼虫人工饲料中添加不同浓度的Zn²⁺,测定了连续3代取食含不同Zn²⁺浓度饲料幼虫的血淋巴中Zn²⁺含量,并研究了被Zn²⁺胁迫的斜纹夜蛾幼虫对寄生性天敌双斑侧沟茧蜂Microplitis bicoloratus Chen生存与发育的影响。结果表明,斜纹夜蛾幼虫血淋巴中Zn²⁺含量随饲料中Zn²⁺浓度和幼虫取食世代数的增加而增加;Zn²⁺胁迫斜纹夜蛾幼虫对双斑侧沟茧蜂的寄生率、从寄生到结茧的时间、蛹期长短、成虫羽化率和成虫寿命等都有不同程度的影响,其中以第2代的寄生率和第1代的羽化率受影响最大,均随着Zn²⁺浓度的增大而降低。因此,寄主饲料中高浓度的Zn²⁺能通过食物链影响双斑侧沟茧蜂的生存和发育。     

植物提取物和药剂对蔬菜蚜虫实验和自然种群的联合控制作用

研究白蝴蝶（Syngonium podophyllum ）乙醇提取物、苍耳（Xanthium sibiricum ）乙醇提取物、机油乳剂和0.3%印楝素乳油对桃蚜（Myzus persicae）和萝卜蚜（Lipaphis erysimi）的控制效果.室内四因子（1/2实施）二次正交回归旋转组合设计测试对有翅蚜的忌避作用,结果表明,对有翅桃蚜的主要忌避作用物为苍耳乙醇提取物,当苍耳提取物与白蝴蝶乙醇提取物混用,以及机油乳剂和印楝素混用时,对桃蚜有翅蚜的忌避效果提高;而对萝卜蚜有翅蚜的忌避作用主要受苍耳提取物和白蝴蝶提取物的影响.这些干扰作用均是非线性的.田间试验结果,单独使用白蝴蝶提取物对有翅成蚜有较强的驱避作用;对萝卜蚜自然种群的干扰控制作用以4种植物提取物和药剂混配效果最好,达95.7%;对桃蚜自然种群干扰控制效果最好的则是白蝴蝶提取物,控制效果达87%;同时,白蝴蝶提取物与印楝素乳油混配以及苍耳提取物与印楝素乳油混配,对两种蚜虫的控制效果均达80%以上.