家蝇抗菌肽对细菌细胞表面特性影响及其作用机理的研究

利用微生物对十六烷吸附的方法(MATS方法)、微电泳方法与测定细菌质膜上β-半乳糖苷酶活性的方法,探讨了家蝇抗菌肽对大肠杆菌等6种细菌细胞表面特性及其细胞膜的作用机制。研究结果表明,抗菌肽使细菌表面电负性增强,对G 细菌细胞表面电荷的改变大于对G-的改变,使细菌细胞表面疏水性不同程度的下降。抗菌肽引起细菌细胞膜通透性迅速增加,不同细菌β-半乳糖苷酶释放的最大速度VP在3.86pmol/min～6.92pmol/min,相应的时间TP为0,由此推测抗菌肽对细胞膜的作用机制是“形成孔洞”。     

大庆油田微生物采油现场试验进展

本文介绍近十几年以来大庆油田利用具有产气、降解原油、产生物表面活性剂及堵调性能的菌剂,通过地下发酵,开展微生物采油现场试验取得的进展.分析了该项技术适用的油藏条件和应用特点.截止到2012年底,应用微生物采油技术增产原油达12×104 t.其中微生物单井吞吐518口,累计增油6.3×104t,实施微生物驱和调驱项目10项(45个井组),累计增油5.7×104 t,为大庆油田稳产发挥了重要作用.     

Frequency of resistance to chloramphenicol and tetracyclines among 12014Salmonella strains isolated in 1958 and 1959

Summary In the course of 1958 and 1959 12014Salmonella strains were collected and tested for antibiotic susceptibility. 250 or 2.08 per cent of these strains were found resistant to tetracycline, to chloramphenicol or both antibiotics. In the majority of cases it could be established that resistance was due to the application of these drugs in therapeutic or prophylactic doses.     

Three newSalmonella types (S. Bilthoven,S. wassenaar andS. bonaire

Summary Two newSalmonella types,S. bilthoven, 47ac: a:—andS. wassenaar, 50; gp—were isolated from reptiles in the Netherlands. A newSalmonella type,S. bonaire 50; z₄z₃₂:— was isolated from a cow on the Island Bonaire.     

Seven newArizona serotypes isolated from reptiles

Summary Seven newArizona serotypes from snakes are described. The biochemical characteristics of the organisms were those of typical members of theArizona group. The antigenic formulae of the types are 1,4: 1,6,7; 1,4: 1,6,7,9; 5: 29: 25; 5: 33: 25; 24: 23: 31; 26: 32: 30; and 26: 33: 31. Attention is called to the antigenic relationships of the cultures to theSalmonella group.     

Four newSalmonella types (S. tilburg,S. bunnk,S. overschie andS. sterrenbos) isolated in the Netherlands

Summary Four newSalmonella types isolated in the Netherlands are described.S.tilburg, 1,3,19; d∶1, w, was isolated from the lymphnodes of a swine.S.bunnik, 43; z42:-, was isolated from a reptile.S.overschie, 51; 1,v∶1,5 was isolated from a tortoise.S.sterrenbos, 6,8;d: enx, was isolated from the lymphnodes of a patient.     

Devenir de la putrescine-1,4-14C chez Glycine max

Fate of Putrescine-1,4-¹⁴C in Glycine max Putrescine-1,4-¹⁴C was supplied to young decotylized Glycine max (L.) Merr. cv. Chippewa plants growing under aseptic conditions on a liquid medium with nitrogen supplied either as ammonium chloride or nitrates. Whatever the source of nitrogen the diamine was quickly transformed to γ-aminobutyric acid, succinic acid and malic acid; only a very minor part was utilized for the synthesis of polyamines. In the presence of ammonium chloride the putrescine catabolism may be slower than in the presence of nitrates. The results are explained by a weak isotopic dilution or by a diamine oxidase activity lower in “ammonium” plants than in “nitrate” plants; the two causes might co-exist. The possibility of a diamine compartmentation has to be considered.     

Studies on the coexistence of three species of Eupteryx (Hemiptera: Cicadellidae) on nettle

An account is given of the relative numbers of adults of three species of Eupteryx, coexisting on nettle, collected regularly over a period of seven years, and possible causes of fluctuations are suggested.