口腔修复膜植入预防腮腺手术后Frey综合征

目的:观察口腔修复膜(异种脱细胞真皮基质)植入对腮腺术后Frey综合征的预防作用。方法:我科近五年来施行的腮腺手术病人共75例,其中35例选择在皮瓣与腮腺床之间植入口腔修复膜,术后随访1-2年,以患者主观症状判断是否存在Frey综合征。结果:在未使用口腔修复膜的患者中,有29例(72.5%)出现Frey综合征的症状,在使用修复膜的患者中只有1例(2.9%)出现症状。两组之间有显著性差异(P<0.01)。结论:口腔修复膜(异种脱细胞真皮基质)能有效预防腮腺手术后Frey综合征的发生。     

美洲大蠊内生菌几丁质酶基因的克隆、表达及其活性研究 *

Objective: To clone the chitinase gene ChiA from the endophytes of Periplaneta americana soluble expression of the protein and to identify its function.Methods:The chitinase gene ChiA was amplified by PCR from the DNA of Serratia marcescens,which was separated from the gut of Periplaneta americana and obtained by subcloning. The expression plasmid ChiA/pET21b was constructed and analyzed by bioinformatics. The plasmid was transformed into E. coli BL21(DE3) and the postive strains were induced by IPTG at 20℃ for 20h. The bioactivity of the protein was determined by small punch test.Results:The cloned sequence was associated with Serratia marcescens ChiA gene of GenBank and their homology was 99%. The sequence encoded a protein containing of 571 amino acids and expressed stably in prokaryotic system.SDS-PAGE/Western blot show that the soluble target protein was obtained. The small punch test suggested that the target protein had the activity of decomposing chitin and was stronger than that of the Serratia marcescens.Conclusion:The chitinase gene ChiA of the Serratia marcescens from the gut of Periplaneta americana was cloned successfully. The soluble chitinase that shows marked bioactivity was attained by prokaryotic expression system, which has provided theoretical basis for its further application.     

柚皮甙提取工艺的初步研究

比较了柚果中不同原料柚皮甙的含量;对柚皮中柚皮甙的最佳提取工艺条件进行了研究,并对获得的产品进行了定性.     

透明颤菌血红蛋白基因在地衣芽孢杆菌ATCC9945a中的表达及作用

目的:研究透明颤菌血红蛋白基因(vgb)在产聚γ-谷氨酸(γ- PGA)的地衣芽孢杆菌ATCC9945a中的表达及对其生物量和产量的影响.方法:以大肠杆菌-枯草芽孢杆菌的穿梭表达载体pUBC19为骨架,构建含有枯草芽孢杆菌的组成型启动子P43和透明颤菌血红蛋白结构基因的穿梭表达载体pUBC19 - PV,并通过电击转化得到重组的产γ-PGA的地衣芽孢杆菌(B.licheniformis).一氧化碳差光谱验证重组B.licheniformis 中是否表达了有活性的血红蛋白.摇瓶发酵试验研究重组菌株和对照菌株生物量和发酵产物产量的变化.结果表明,重组菌株的生长明显比对照菌株快,但是γ - PGA的产量却比原始菌株低:在正常供氧时,其产量12.8g/L,比亲株产量21.7g/L下降了41%,贫氧环境下产量8.8g/L,比亲株产量12.8g/L降低了31%.结论:vgb 在重组菌株中表达了有活性的的透明颤菌血红蛋白,并可以促进细胞的生长,但聚谷氨酸的产量却有所下降.文章针对聚γ-谷氨酸产量的下降原因进行了讨论,并对下一步的工作提出了建议.     

西双版纳热带季节雨林粗木质物残体储量及其空间分布

粗木质物残体(CWD)在森林生态系统的物质循环和碳动态中发挥着重要作用,但目前国内对热带地区CWD储量与其空间分布关系上的研究还处于起步阶段。对西双版纳1hm2热带季节雨林样地调查发现,≥10cm的粗木质物残体占森林总凋落物量的68.02%,其中45.72%的CWD处于腐解中后期。由于多数大径级的CWD分布于15°～25°的坡地上,且其饱和持水力随腐解等级的增加而上升,因此,CWD将有助于改善坡地生境下的水肥条件。CWD的分布受风向和本地湿热环境的影响,但掉落指向则更倾向于随机过程。CWD产生和分布上的普遍性有可能对森林生境异质性和生物多样性产生重大影响。     

针对DREAM 基因序列外显子的siRNA 设计

目的:针对DREAM基因中外显子序列,设计并筛选出起作用的siRNA,为进一步研究以DREAM为靶标的基因治疗提供依据。方法:通过利用生物信息学的方法设计出66条潜在的针对DREAM基因中外显子序列的siRNA序列。潜在的序列根据G+C含量分析及Genbank BLAST检测,我们筛选了三条较理想的DREAM基因siRNA靶标,并将其构建到pENTR/H1/TO载体中,转染细胞后提取总蛋白并用Western blot方法检测DREAM蛋白的表达水平。结果:示外显子9中5’末端位置为1253的序列能够抑制80%的DREAM的蛋白表达。结论:这一研究结果为进一步siRNA类药物的实验研究提供了理论基础。     

Expression of the antimicrobial peptide cecropin fused with human lysozyme in Escherichia coli

Lysozyme is an abundant, cationic antimicrobial protein that plays an important role in host defense. It targets the β (1–4) glycosidic bond between N-acetylglucosamine and N-acetylmuramic residues that make up peptidoglycan, making lysozyme highly active against Gram-positive bacteria. However, lysozyme alone is inactive against Gram-negative bacteria because it cannot reach the peptidoglycan layer. Cecropins are cationic molecules with a wide range of antimicrobial activities. The main target for these peptides is the cytoplasmic membrane. We resume that cecopin may disrupt the outer membrane, giving the enzyme access to the peptidoglycan in cell wall. So in the present study, novel hybrid protein combining Musca domestica cecropin (Mdc) with human lysozyme (Hly) was designed. The DNA sequence encoding recombination fusion protein Mdc–hly was cloned into the pET-32a vector for protein expression in Escherichia coli strain BL21 (DE3). The protein was expressed as a His-tagged fusion protein, and the Mdc–hly was released from the fusion by enterokinase cleavage and separated from the carrier thioredoxin. Antimicrobial activity assays showed that the recombinant fusion protein Mdc–hly has improved in vitro antimicrobial activity and action spectrum compared to Mdc and hly. Mdc–hly may have important potential application as a future safely administered human drug and food additive.     

西双版纳热带季节雨林优势植物热值

为探讨西双版纳热带季节雨林植物热值的变化规律,用SDACM-Ⅲa型量热值仪测定了该群落不同层次37种优势植物不同器官干湿季节的热值。结果表明:西双版纳热带季节雨林各层优势种的平均干质量热值在17.05～20.23kJ.g-1,乔木、层间藤本、灌木、草本干质量热值分别为18.86～20.23、17.97～19.76、17.71～18.83和17.05～17.45kJ.g-1。各层优势种平均干质量热值在干湿季节均表现为:乔木层>层间藤本>灌木层>草本层。所有层次相同各器官平均干质量热值在器官间存在差异,但只有叶与根、枝之间差异显著(P<0.05);不同层次中的同种植物干质量热值在干湿季节差异均不显著(P>0.05);各层优势植物的干质量热值在干湿季节之间差异不显著(P>0.05)。