Physiological factors affecting transformation of Azotobacter vinelandii.

摘要: Cells of Azotobacter vinelandii (ATCC 12837) can be transformed by exogenous deoxyribonucleic acid towards the end exponential growth. Transformation occurs at very low frequencies when is purified or transformation carried out in liquid medium. Optimal on plates Burk nitrogen-free glucose medium containing either high phosphate (10 mM) calcium (0 to 0.29 content. Higher levels are inhibitory, whereas magnesium ions essential for and Extracellular polymer capsule increasingly inhibitory most abundant content high. optimal pH 7.0 7.1 30 C, conditions which also coincide with minimal extracellular production. Nonencapsulated strains excellent recipients. Glycine-induced pleomorphism reduces frequency degree inhibition dependent concentration Rifampin resistance shifts from adenine, hypoxanthine, uracil, nitrogenase auxotrophy prototrophy achieved. Although single marker transfer always greater than double transfer, data suggest that rifampin linked adenine uracil protorophy intervals increasing distance. did not appear nitrogenase.