Adler H, Mural R, Suttle B
Medical Sciences Division, Oak Ridge Associated Universities, Tennessee 37831-0117.
J Bacteriol. 1992 Apr;174(7):2072-7. doi: 10.1128/jb.174.7.2072-2077.1992.
Genetic evidence indicates that Oxys-6, an oxygen-sensitive mutant of Escherichia coli AB1157, is defective in the region of the hemB locus. Oxys-6 is capable of growth under aerobic conditions only if cultures are initiated at low-inoculum levels. Aerobic liquid cultures are limited to a cell density of 10(7) cells per ml by the accumulation of a metabolically produced, low-molecular-weight, heat-stable material in complex organic media. Both Oxys-6 and AB1157 cells produce the material, but only aerobic cultures of the mutant are inhibited by it. The material is produced by both intact cells and cell extracts in complex media. This reaction also occurs when the amino acid L-lysine is substituted for complex media.
遗传证据表明，大肠杆菌AB1157的氧敏感突变体Oxys-6在hemB基因座区域存在缺陷。只有在低接种量下开始培养时，Oxys-6才能在有氧条件下生长。在复杂有机培养基中，有氧液体培养物会因代谢产生的一种低分子量、热稳定物质的积累而限制在每毫升10(7)个细胞的细胞密度。Oxys-6和AB1157细胞都会产生这种物质，但只有突变体的有氧培养物会受到其抑制。这种物质在复杂培养基中由完整细胞和细胞提取物产生。当用氨基酸L-赖氨酸替代复杂培养基时，也会发生这种反应。
