20种植物提取物抑制植物病原菌活性研究

以小麦纹枯病菌(Rhizoctonia cerealis)、番茄灰霉病菌(Alternaria solani)这两种植物病原真菌为供试菌,对采自江西省吉安市的20种植物提取物的抑制菌丝生长活性及孢子萌发进行测定.结果表明,在供试质量浓度为1 mg/mL时,黄花草木樨乙醇提取物的乙酸乙酯萃取部分抑菌效果最好,对小麦纹枯病菌和番茄灰霉病菌两种菌的抑制率均达100%;窃衣、小白酒草、羊蹄和车前草的抑制作用次之,对两种菌的抑制率均大于80%;单从对一种病原菌的抑制作用看,还有黄荆对小麦纹枯病菌率为100%,空心莲子草、窃衣、小白酒草和鬼针草对番茄灰霉病菌的抑制率为100%,但是,这20种供试植物的石油醚相和水相萃取物对两种病原真菌的抑制效果均不强.抑制病原菌孢子萌发亦得到类似结果.以上结果提示植物抑菌活性成分主要存在于乙酸乙酯萃取部分,黄花草木樨、窃衣、小白酒草等的提取物作为植物源杀菌剂值得进一步研究.     

Reprogramming of sugar transport pathways in Escherichia coli using a permeabilized SecY protein-translocation channel

In the initial step of sugar metabolism, sugar-specific transporters play a decisive role in the passage of sugars through plasma membranes into cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. The present work shows that permeabilized SecY channels can be used as nonspecific sugar transporters in Escherichia coli. SecY with the plug domain deleted allowed the passage of glucose, fructose, mannose, xylose, and arabinose, and, with additional pore-ring mutations, facilitated lactose transport, indicating that sugar passage via permeabilized SecY was independent of sugar stereospecificity. The engineered E. coli showed rapid growth on a wide spectrum of monosaccharides and benefited from the elimination of transport saturation, improvement in sugar tolerance, reduction in competitive inhibition, and prevention of carbon catabolite repression, which are usually encountered with native sugar uptake systems. The SecY channel is widespread in prokaryotes, so other bacteria may also be engineered to utilize this system for sugar uptake. The SecY channel thus provides a unique sugar passageway for future development of robust cell factories for biotechnological applications.     

B-Myb稳定过表达H1299细胞株的构建与分析

B—Myb是Myb家族的成员之一,在细胞周期和癌变过程中具有重要作用。但其在肺癌中的作用及其分子机制仍不清楚。为了研究B—Myb在肺癌中的作用,构建了B-Myb稳定过表达的H1299肺癌细胞株。流式细胞术和MTT检测的结果表明,B—Myb稳定过表达导致G1期细胞减少,S期细胞增加进而促进细胞增殖：克隆形成实验及Transwell的结果表明,B—Myb稳定过表达显著增强H1299细胞的克隆形成、侵袭及迁移能力。定量RT-PCR检测结果表明,B—Myb稳定过表达显著提高了细胞周期基因CCNA1的表达水平;对CD97和MTSS1等细胞运动相关下游基因的表达则无明显影响。该研究成功构建了B-Myb稳定过表达细胞株,发现了B-Myb过表达可促进肺癌细胞的增殖、侵袭迁移及克隆形成能力,为进一步研究奠定了基础。     

Kronecker积在分析多因子非平衡实验中的应用

以Kroneckert积和效应矩阵为工具,阐明了一种分析多因子缺值实验的严格、有效、方便的新方法。     

Antioxidant status and lipid peroxidation in hemodialysis patients undergoing erythropoietin and erythropoietin-vitamin E combined therapy.

In this study, plasma and red blood cell (RBC) antioxidant status and plasma lipid peroxidation were investigated in 46 hemodialysis patients. In addition, the effect of erythropoietin (EPO) and EPO-vitamin E combination therapy on plasma and RBC antioxidant status, and plasma lipid peroxidation were examined. There were 10 healthy subjects in the control group and 10 hemodialysis patients in the untreated group. The third group included 36 hemodialysis patients that were given EPO (100 U/kg) for 3 months, 3 times per week. The fourth group included 36 hemodialysis-patients from the EPO group that were given EPO at a 50% decreased dose + vitamin E (300 mg/day) for 3 months. MDA levels in the untreated group, the EPO group and the EPO + vitamin E groups were found to be higher than the control group (p < 0.001, in both). Furthermore, MDA levels in both of the treatment groups were lower when compared to the untreated group (p < 0.001, in both). Plasma vitamin E levels in the untreated, the EPO group and EPO + vitamin E groups were lower than the control group (p < 0. 001). In contrast, plasma vitamin E levels in the treatment groups were higher in comparison with the control group (p < 0.05). SOD activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001). SOD activities in the treatment groups were higher than the control group (p<0.001). The SOD activities in the EPO+vitamin E group increased when compared to the EPO group (p < 0.001). CAT activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001 in untreated and EPO groups, p <0.01 in EPO+ vitamin E group). CAT activities in EPO and EPO+ vitamin E groups were increased when compared to the untreated group (p < 0.01). In conclusion, our findings have shown that antioxidant status decreased and lipid peroxidation increased in hemodialysis patients. EPO has an antioxidant effect on the RBC and plasma antioxidant status, and plasma lipid peroxidation. These effects were moderately increased by the combination of vitamin E and EPO.     

Structure, stability, and chaperone function of alphaA-crystallin: role of N-terminal region

Small heat shock protein alphaA-crystallin, the major protein of the eye lens, is a molecular chaperone. It consists of a highly conserved central domain flanked by the N-terminal and C-terminal regions. In this article we studied the role of the N-terminal domain in the structure and chaperone function of alphaA-crystallin. Using site directed truncation we raised several deletion mutants of alphaA-crystallin and their protein products were expressed in Escherichia coli. Size exclusion chromatography of these purified proteins showed that deletion from the N-terminal beyond the first 20 residues drastically reduced the oligomeric association of alphaA-crystallin and its complete removal resulted in a tetramer. Chaperone activity of alphaA-crystallin, determined by thermal and nonthermal aggregation and refolding assay, decreased with increasing length of deletion and little activity was observed for the tetramer. However it was revealed that N-terminal regions were not responsible for specific recognition of natural substrates and that low affinity substrate binding sites existed in other part of the molecule. The number of exposed hydrophobic sites and the affinity of binding hydrophobic probe bis-ANS as well as protein substrates decreased with N-terminal deletion. The stability of the mutant proteins decreased with increase in the length of deletion. The role of thermodynamic stability, oligomeric size, and surface hydrophobicity in chaperone function is discussed. Detailed analysis showed that the most important role of N-terminal region is to control the oligomerization, which is crucial for the stability and in vivo survival of this protein molecule.     

山西历山珍稀药用植物AM真菌资源与土壤因子的关系

以山西历山自然保护区暴马丁香、连香树、南方红豆杉和领春木4种珍稀药用植物为材料,研究其根际土壤中丛枝菌根真菌(AMF)的菌根结构类型和种属分布,同时分析土壤因子与其侵染率和孢子密度的关系。结果表明:(1)暴马丁香菌根类型为中间型(I-型),连香树和领春木为重楼型(P-型),南方红豆杉为疆南星型(A-型);4种植物根际共鉴定AMF 27种,分别隶属于球囊霉属(Glomus)、无梗囊霉属(Acaulospora)、盾巨孢囊霉属(Scutellos-pora)、多孢囊霉属(Diversispora)和原囊霉属(Archaeospora)5属,其中Glomus为优势属。(2)pH与暴马丁香和领春木的侵染率和孢子密度呈正相关,但与连香树和南方红豆杉呈负相关;速效磷与暴马丁香、南方红豆杉和领春木的侵染率和孢子密度呈正相关,但与连香树呈负相关;碱解氮、有机质与暴马丁香、连香树和领春木的侵染率和孢子密度呈正相关,但与南方红豆杉呈负相关。(3)4种药用植物的菌根侵染率主要受其根际土壤碱解氮的影响,而根际AMF孢子密度主要受根际土壤pH制约。可见,历山自然保护区内AMF资源丰富,多样性程度也较高;宿主植物不同,土壤因子对其侵染率和孢子密度的影响也不同。     

广西陆栖兽类动物分布格局及区划探讨

根据广西陆栖兽类种类,数量和分布特点。结合自然地理条件,探讨了广西陆栖兽类支持发布格局,并将广西兽类地理区划为7个小区：Ⅰ桂西南缘山地小区;Ⅱ桂南沿海台地平原小区;Ⅲ桂西南丘陵盆地小区;Ⅳ桂中丘陵山地小区;Ⅴ桂中及桂东低丘台地,山地,谷地小区;Ⅵ桂西北岩溶山原盆坝小区;Ⅶ桂东北南岭山地小区。广西陆栖兽类区域分化不明显,而受地形因素的更显著,海拔较高的桂西,北边缘山地区系成分较为近似,而与东部和南部沿海低海拔的丘陵,低山及盆地形成较明显的差异。盆地内弧形山脉的动物区系别具特色。