Chemical Composition of Azotobacter vinelandii Cysts

摘要: Cysts of Azotobacter vinelandii ATCC 12837 were germinated by exposure to 3.0 mm ethylenediaminetetraacetic acid (EDTA)-tris(hydroxymethyl)aminomethane buffer at pH 7.8, and their outer coats (exines) purified differential isopycnic centrifugation. Electron micrographs exine showed it consist multilayers a three-membered sheet structure whose thickness was 7.0 7.5 nm. The inner, less electron-dense layer (intine) also prepared from cysts EDTA treatment, centrifugation, concentration, dialysis. consisted 32% carbohydrate, 28% protein, 30% lipid, 3.2% ash, with the ash comprised 1.62% calcium, 0.02% magnesium, 0.34% phosphorus. amino composition similar that gram-negative bacterial cell walls. intine 44% 9.1% 37% 4.1% 2.45% 0.38% carbohydrates both contained glucose, mannose, xylose, rhamnose. Glucosamine galactosamine found only in exines. fatty acids normal, iso, anteiso saturated 10 18 carbon atoms mono-unsaturated C(11), C(16), C(18) acids. exines mostly bound but intines primarily free lipid.