Alaeddinoglu N G, Charles H P
J Gen Microbiol. 1979 Jan;110(1):47-59. doi: 10.1099/00221287-110-1-47.
As the first stage in investigating the genetic basis of natural variation in Escherichia coli, the gene(s) conferring the ability to use sucrose as a carbon and energy source (given the symbol sac+) was transferred from a wild strain to K12, which does not use sucrose. The sac+ region was transferred by two different methods. On both occasions it took a chromosomal location at minute 50.5 on the linkage map, between aroC and supN, in the region of the dsd genes, which confer the ability to use D-serine as a carbon and energy source. When the sac+ region was present in the K12 chromosome the bacteria were unable to use D-serine as a carbon and energy source. In F' sac+/dsd+ diploids, the dsd+ genes were similarly not expressed. Strain K12(sac+) bacteria were sensitive to inhibition by D-serine; they mutated to D-serine resistance with much greater frequency than did a dsd mutant of K12. Such bacteria also mutated frequently to use raffinose. Strain K12(sac+) bacteria did not utilize sucrose when they carried a mutation affecting the phosphotransferase system.
作为研究大肠杆菌自然变异遗传基础的第一阶段，赋予利用蔗糖作为碳源和能源能力的基因（符号为sac +）从野生菌株转移到不利用蔗糖的K12菌株。通过两种不同方法转移sac +区域。两次转移后它都位于连锁图谱上第50.5分钟处的染色体位置，在aroC和supN之间，处于dsd基因区域，dsd基因赋予利用D - 丝氨酸作为碳源和能源的能力。当sac +区域存在于K12染色体中时，细菌无法利用D - 丝氨酸作为碳源和能源。在F' sac + / dsd +二倍体中，dsd +基因同样不表达。K12（sac +）菌株对D - 丝氨酸的抑制敏感；它们突变为对D - 丝氨酸抗性的频率比K12的dsd突变体高得多。这类细菌也经常突变为能利用棉子糖。当K12（sac +）菌株携带影响磷酸转移酶系统的突变时，它们不能利用蔗糖。
