Krulwich T A, Ensign J C
J Bacteriol. 1969 Feb;97(2):526-34. doi: 10.1128/jb.97.2.526-534.1969.
Succinate and several other compounds which induce sphere to rod morphogenesis of A. crystallopoietes were found to suppress both catabolism and assimilation of glucose. Diauxic growth patterns resulted from growth on glucose plus any one of these compounds. Glutamate stimulated growth but was not an inducer of morphogenesis. With this compound, diauxic growth and suppression of glucose catabolism or assimilation did not occur. Glucose permease was studied with alpha-methylglucoside as substrate. The entry system for glucose was found to involve active transport and to have a K(m) of 8 x 10(-4)m. It was inducible, was repressed in succinate-grown cells, and was also inhibited by succinate. The exit system was constitutive and appeared to be less sensitive than the entry system to inhibition by azide. The properties of the glucose permease system may account for the slow growth of the organism on glucose and the preferred use of other substrates for growth. Studies of metabolic pathways for glucose metabolism indicated the operation of the Embden-Meyerhof-Parnas (EMP) and pentose phosphate pathways and of the tricarboxylic acid cycle. Cells grown on glucose plus limiting amounts of succinate or other inducers of morphogenesis metabolized the glucose only after exhaustion of the inducers. Under these circumstances, the organisms employed the EMP pathway to a greater extent than when growing on glucose as sole carbon source.
琥珀酸和其他几种能诱导晶状产气杆菌由球状形态转变为杆状形态的化合物,被发现可抑制葡萄糖的分解代谢和同化作用。在葡萄糖与这些化合物中的任何一种共同存在的情况下生长,会产生双相生长模式。谷氨酸能刺激生长,但不是形态发生的诱导剂。对于这种化合物,不会出现双相生长以及葡萄糖分解代谢或同化作用的抑制。以α-甲基葡萄糖苷为底物研究了葡萄糖通透酶。发现葡萄糖的进入系统涉及主动运输,其米氏常数(K(m))为8×10⁻⁴m。它是可诱导的,在琥珀酸培养的细胞中受到抑制,并且也受到琥珀酸的抑制。输出系统是组成型的,并且似乎比进入系统对叠氮化物抑制的敏感性更低。葡萄糖通透酶系统的特性可能解释了该生物体在葡萄糖上生长缓慢以及优先利用其他底物进行生长的现象。对葡萄糖代谢途径的研究表明,存在糖酵解途径(Embden-Meyerhof-Parnas,EMP)、磷酸戊糖途径和三羧酸循环。在葡萄糖加有限量琥珀酸或其他形态发生诱导剂的条件下生长的细胞,仅在诱导剂耗尽后才代谢葡萄糖。在这些情况下,与以葡萄糖作为唯一碳源生长时相比,生物体更多地利用EMP途径。