Page W J, von Tigerstrom M
Can J Microbiol. 1978 Dec;24(12):1590-4. doi: 10.1139/m78-254.
Azotobacter vinelandii strains UW (Nif+) or UW1 (Nif-) were induced to form competent cells by growing cultures in Burk medium without added iron. Competent cells were generated in either liquid or solid medium. The competent culture was highly colored by the characteristic fluorescent green pigment of A. vinelandii but all pigmented cultures were not competent. In liquid culture, competent cells required a fixed nitrogen source (ammonia, nitrate, or urea) that was also a nitrogenase repressor. Glucose, sucrose, glycerol, and mannitol (1% w/v) were excellent C-sources for competence induction while acetate (1% w/v) and beta-hydroxybutyrate (0.2% w/v) were ineffective. Cells induced in liquid culture remained competent for a 12-h period before the end of the exponential growth phase, then competence decreased rapidly upon the initiation of the stationary phase of growth.
通过在不添加铁的伯克培养基中培养，诱导维涅兰德固氮菌菌株UW（固氮阳性）或UW1（固氮阴性）形成感受态细胞。感受态细胞可在液体或固体培养基中产生。感受态培养物因维涅兰德固氮菌特有的荧光绿色色素而颜色很深，但并非所有有色素的培养物都是感受态的。在液体培养中，感受态细胞需要一种固定氮源（氨、硝酸盐或尿素），而这种氮源也是固氮酶的阻遏物。葡萄糖、蔗糖、甘油和甘露醇（1% w/v）是诱导感受态的优良碳源，而乙酸盐（1% w/v）和β-羟基丁酸盐（0.2% w/v）则无效。在液体培养中诱导的细胞在指数生长期结束前的12小时内保持感受态，然后在生长进入稳定期时感受态迅速下降。
