Bradley S, Carr N G
J Gen Microbiol. 1976 Sep;96(1):175-84. doi: 10.1099/00221287-96-1-175.
The differentiation of filaments of a continuous culture of Anabaena cylindrica after removal of fixed nitrogen has been examined. Rapid development of proheterocysts (4-5 h) and mature heterocysts (14 h) in an ordered sequence was observed; the development of the latter was concomitant with the onset of nitrogenase activity. Commitment times of 2-3 h (proheterocyst) and 5-0 (heterocyst) were measured. Evidence is presented that shows that heterocyst development, rather than any product of heterocyst function in nitrogen fixation, is responsible for the imposition of the pattern of heterocysts in a filament of vegative cells. Both phycocyanin content and carbon dioxide fixation declined markedly throughout the filament during the early stages of heterocyst development, indicating that all the cells of the filament are involved in the initial stages of the differentiation process. Heterocysts do not evolve oxygen in the light, but do respire. Nitrogenase activity in isolated heterocysts and in intact filaments was stimulated by phosphoenolpyruvate, ATP and dichlorophenolindophenol-ascorbate.
已对去除固定氮后圆柱鱼腥藻连续培养物中丝状体的分化进行了研究。观察到原异形胞（4 - 5小时）和成熟异形胞（14小时）按有序序列迅速发育；后者的发育与固氮酶活性的开始同时发生。测定了原异形胞的2 - 3小时和异形胞的5 - 0小时的确定时间。有证据表明，异形胞的发育而非异形胞在固氮作用中的任何产物，是负责在营养细胞丝状体中形成异形胞模式的原因。在异形胞发育的早期阶段，整个丝状体中的藻蓝蛋白含量和二氧化碳固定均显著下降，这表明丝状体的所有细胞都参与了分化过程的初始阶段。异形胞在光照下不释放氧气，但会进行呼吸作用。分离的异形胞和完整丝状体中的固氮酶活性受到磷酸烯醇丙酮酸、ATP和二氯酚靛酚 - 抗坏血酸的刺激。
