Woodward M J, Charles H P
J Gen Microbiol. 1983 Jan;129(1):75-84. doi: 10.1099/00221287-129-1-75.
Amongst forty wild strains of Escherichia coli, sixteen utilized galactitol (as did K12) and seven utilized ribitol (as did C) of which six utilized D-arabitol; none utilized all three polyols. Transduction of genes for ribitol utilization (rtl+) to strains able to utilize galactitol (gat+), whether K12 or wild strains, using wild strains and E. coli C as donors always resulted in loss of the galactitol phenotype. The genes for D-arabitol use (atl+) were always cotransduced with rtl+ in interstrain crosses. We confirm and extend the mapping of gat+ (Lengeler, 1977) and rtl+ atl+ (Reiner, 1975) in their respective hosts, K12 and C, by showing both regions to be 50% cotransducible with metG and 3% cotransducible with fpk. In reciprocal transductions, gat+ replaced rtl+ atl+. In partial diploids, rtl+ atl+ and gat+ regions did not interfere with each other's expression. Transfer of rtl+ from an Rtl+ Atl- donor by R plasmid (pE10)-mediated conjugation, gave Gat- transconjugants of K12 in which rtl+ and a kanamycin resistance gene were 100% cotransducible in the metG region of the chromosome. It is suggested that the rtl+ atl+ and gat+ genes (or parts of them) act as alternative, or mutually exclusive, regions in the chromosome. Possible reasons for the existence of alternative characters are discussed.
在四十株野生大肠杆菌菌株中，有十六株能利用半乳糖醇（K12菌株也是如此），七株能利用核糖醇（C菌株也是如此），其中六株能利用D -阿拉伯糖醇；没有菌株能利用所有这三种多元醇。利用野生菌株和大肠杆菌C作为供体，将核糖醇利用基因（rtl +）转导到能利用半乳糖醇的菌株（gat +）中，无论是K12菌株还是野生菌株，总是导致半乳糖醇表型的丧失。在菌株间杂交中，D -阿拉伯糖醇利用基因（atl +）总是与rtl +共转导。我们通过显示gat +（Lengeler，1977）和rtl + atl +（Reiner，1975）在各自宿主K12和C中与metG的共转导率为50%，与fpk的共转导率为3%，从而证实并扩展了它们在各自宿主中的定位。在 reciprocal 转导中，gat +取代了rtl + atl +。在部分二倍体中，rtl + atl +和gat +区域不相互干扰表达。通过R质粒（pE10）介导的接合从Rtl + Atl -供体转移rtl +，得到K12的Gat -转导子，其中rtl +和卡那霉素抗性基因在染色体的metG区域共转导率为100%。有人提出rtl + atl +和gat +基因（或其部分）在染色体中作为替代或相互排斥的区域起作用。讨论了替代性状存在的可能原因。
