McIver C J, Tapsall J W
Department of Microbiology, Prince of Wales Hospital, Sydney.
Pathology. 1987 Oct;19(4):361-3. doi: 10.3109/00313028709103884.
The requirements for cysteine of naturally occurring cysteine auxotrophs of Escherichia coli were determined in a defined liquid medium. Maximal growth was obtained in the presence of cysteine concentrations between 20 and 250 mg/l. At concentrations below 20 mg/l growth of the auxotrophs, but not the prototrophic control, was suboptimal in this system. In the presence of cysteine concentrations in excess of 250 mg/l, growth of both auxotrophic and prototrophic E. coli was inhibited with lower growth yields, a decreased specific growth rate and an extended lag phase being observed. These effects were minimised in the presence of 2 mM L-leucine, L-isoleucine and L-valine.
在一种特定的液体培养基中测定了大肠杆菌天然存在的半胱氨酸营养缺陷型对半胱氨酸的需求。在半胱氨酸浓度为20至250毫克/升的情况下可实现最大生长。在该系统中，当浓度低于20毫克/升时，营养缺陷型的生长（但原养型对照的生长并非如此）未达最佳状态。当半胱氨酸浓度超过250毫克/升时，营养缺陷型和原养型大肠杆菌的生长均受到抑制，生长产量降低，比生长速率下降，且观察到延迟期延长。在存在2 mM L-亮氨酸、L-异亮氨酸和L-缬氨酸的情况下，这些影响被最小化。
