基于拮抗及ITS序列分析的河南香菇主产区种质资源鉴定及遗传多样性分析

应用核糖体基因转录间隔区域(Internal Transcribed Spacer,ITS)序列及拮抗法对河南食用菌主产区香菇栽培菌株进行鉴定,并分析遗传多样性。以收集的41个香菇栽培菌株为样本,两两之间进行拮抗测试分析,提取DNA并进行PCR扩增、回收、测序,采用比对邻接法(neighbor-joinging,NJ)构建系统进化树。结果表明,16个差异菌株拮抗现象明显,其余菌株无拮抗或者拮抗不显著,41个香菇菌株初步分为16个不同菌株及7个不同亚种;ITS序列比对及系统发育分析将41个香菇品种聚为独立进化的4个大类,即3个不同的菌株和8个不同的亚种,种内遗传距离为0.0000~0.0065,与Pleurotus ostreatus(KY962509)种间遗传距离为0.3740。综上所述,“ITS+拮抗法”结合可以明确区分菌株间拮抗、无拮抗及拮抗不明显现象基因序列的相似度、遗传距离的差异及亲缘关系的远近,为香菇品种的鉴定提供理论支撑。

Screening and Identification of Antagonistic Bacteria against Soil-borne Diseases of Tomato

[Objective] This study was conducted to screen resources for biological control of soil-borne diseases of tomato. [Method] Antagonistic bacteria against Ral- stonia solanacearum and Fusarium oxysporum were isolated and purified from soil samples by dilution plating and confronting incubation on PDA plates, then the antibacterial spectrum and metabolic secretions of the bacterial isolates were measured, and their species were identified by establishing phylogenetic trees with Neighbor-Joining method. [Result] From the 60 soil samples, 10 of 59 antagonistic bacteria isolates against R. solanacearum showed inhibition zone diameter 〉 25 mm, and 4 of 30 strains against F. oxysporum exhibited inhibition rate 〉 30%. The bacteriostatic substances and antibacterial spectrum analysis on above 14 isolates revealed that four strains N23-2, N58-2, NF59-3 and NF61-1 had good antago- nism against pathogenic bacteria and fungi; 12 strains produced cellulose, 11 strains produced proteases, and 6 strains produced siderophores. The molecular identification experiments indicated that four strains were members of Paenibacillus, three strains of Streptomyces, three strains of Pseudomonas strains, and four strains of Bacillus strains.

Characterization of Platelet Activating Factor (PAF)Binding Sites in Rabbit Platelet Membranes

本文用放射配基受体结合实验方法研究了兔血小板膜上血小板活化因子（PAF）受体的性质。[^3H]-PAF与膜的特异结合率达70－80％，在25℃测得PAF与膜结合的平衡解离常数（Kd）为40.8nmol/L，最大结合位点为5.4pmol/mg蛋白。特异的PAF受体拮抗剂海风藤酮对结合有较强的抑制作用，IC50为30.0μmol/L。（－）－denudatin B，樟叶素(polysyphorin）和南藤素（wallichinine）是从中草药中分离的化合物，均能抑制这一结合，其IC50分别为0.6μmol/L、10μmol/L和2.5μmol/L。