一种快速提取禽源性大肠埃希氏菌外胰蛋白的方法

介绍一种快速提取禽源性大肠埃希氏菌外膜蛋白的方法。该法是对Ｋａｐｕｒ等发表的方法的改进。全过程只需超速离心一次,比Ｋａｐｕｒ等的方法缩短了４ｈ。所得样品可直接用于禽源性大肠埃希氏菌外膜蛋白模式的测定。     

霍乱弧菌EL－Tor35A3菌株外膜蛋白主区带的纯化

选用霍乱弧菌ＥＬ－Ｔｏｒ生物型３５Ａ３菌株（血清稻叶型）以ＥＤＴＡ－溶菌酶法与超速离心法提取其外膜蛋白,并将聚丙烯酰胺凝胶电泳后一条蛋白主区带分离。ＳＤＳ－聚丙烯酰胺凝胶电泳测得该蛋白主区带的分子量为２５ｋＤ,免疫电泳显示一条线,免疫双扩试验表明,不同的霍乱弧菌菌株均有该蛋白抗原存在。     

淋球菌主要外膜蛋白的部分纯化与鉴定

应用国产十六烷基三甲基溴化铵提取淋球菌外膜蛋白Ｉ（ＰＩ）,继用Ｓｅｐｈａｒｏｓｅ ６Ｂ纯化,并通过ＳＤＳ－ＰＡＧＥ鉴定所提ＰＩ的纯度,以及用琼脂双扩散法测定其抗原性。该法提取淋球菌ＰＩ的纯度高,收获量大,对抗原结构无破坏,适宜在淋球菌的生物学研究中应用。     

THE FAILURE OF PHENOL TREATED ESCHERICHIA COLI TO GROW ON MEMBRANE FILTERS

SUMMARY: Counts of Escherichia coli were done on nutrient agar (control), on membrane filters on nutrient agar and on membrane filters on filter paper pads. With untreated bacteria counts were similar under all conditions, though membrane filters on nutrient agar tended to give slightly low counts. Phenol treated bacteria gave much lower counts when membrane filters were used: the mean counts for 3 strains of the test organism with filters on nutrient agar varied from 35–65% of the control, while counts with filters on filter paper pads were somewhat lower, varying from 30–47% of the control. The low counts on membrane filters on filter paper pads were not due to adsorption of phenol by the filters or to a low concentration of nutrients in the growth medium.     

MEMBRANE MODIFICATIONS IN NUTRITIONALLY INDUCED FILAMENTOUS ESCHERICHIA COLI B

Nutritionally induced filamentous cell forms of Escherichia coli B were examined for their morphological and biochemical lesions. The filamentous forms showed no significant alteration in total DNA concentration, RNA synthesis, ability to form β-galactosidase in response to isopropylthiogalactoside, or insensitivity to actinomycin D as compared to the normal cell form. The filamentous cells showed a marked decrease in the ability to incorporate N-acetylglucosamine-UL-¹⁴C into a phenol-soluble glycoprotein fraction relative to the normal cell form or relative to strain E-26 of E. coli grown in the filament-inducing medium. The filaments yielded an envelope-specific phenol-soluble protein fraction markedly reduced in or lacking three proteins as determined by acrylamide gel electrophoresis. Amino acid analysis, and chemical and enzymatic treatments of the envelope-specific phenol-soluble proteins showed striking differences between the fractions obtained from normal and filamentous cells. Electron microscope studies of divalent cation-induced aggregates of the envelope proteins showed different aggregation patterns dependent upon the cell form yielding the protein fraction.     

THE RATE OF BACTERIOPHAGE INACTIVATION BY FILTRATES OF ESCHERICHIA COLI CULTURES

1. The rate of inactivation of an anti-coli phage by filtrates of cultures of the homologous bacteria has been studied. 2. The inactivation rate at 37°C. is proportional to phage concentration and filtrate concentration. 3. At 0°C. the rate of phage inactivation becomes proportional to the square root of the filtrate concentration. 4. A reaction scheme to account for these observations is suggested and discussed. 5. This coli-phage is also inactivated by relatively large concentrations of soluble starch, inulin, gum arabic, and acetylated gum arabic. 6. The inactivation is markedly influenced by salt concentration, being rapid at moderate salt concentrations and slow at high or extremely low salt concentrations. 7. The inactivated phage cannot be regenerated by high salt concentrations, or by soaps.