2 MUTATIONS WHICH AFFECT THE BARRIER FUNCTION OF THE ESCHERICHIA-COLI K-12 OUTER-MEMBRANE
2 MUTATIONS WHICH AFFECT THE BARRIER FUNCTION OF THE ESCHERICHIA-COLI K-12 OUTER-MEMBRANE
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DOI：
10.1128/jb.139.3.899-910.1979
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发表时间：
1979-01-01
影响因子：
3.2
通讯作者：
LEIVE, L
中科院分区：
文献类型：
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作者：
COLEMAN, WG;LEIVE, L
从E. coli K-12。一类，给定表型名称NbsA，位于E. coli染色体。根据转导分析，该区域中基因的顺序为proC NbsA plsA purE。第二个，NbsB，位于80分钟。该区域中的基因的顺序，基于转导分析，是xyl cysE NbsB pyrE。这两类突变体显示出对疏水药物的敏感性增加，但不同的是：NbsA细胞倾向于对阳离子剂更敏感，而NbsB细胞显示出相反的趋势。在NbsA菌株中唯一可检测的生化改变是脂多糖的脂质A区域的磷酸盐含量降低大于90%。NbsB突变导致脂多糖主要含有立体异构体D-甘油-D-甘露庚糖，而不是L-甘油-D-甘露庚糖，而不是L-甘油-D-甘露庚糖，并且含有非常少的远端糖。由于NbsA菌株具有明显正常的外膜蛋白和总细胞磷脂，因此仅脂多糖的变化可增加对某些疏水性抗生素的渗透性。互补研究表明，NbsA标记可能与acrA等位。NbsB标记在遗传和表型上与鼠伤寒沙门氏菌的rfaD基因座相似。因此，表型名称NbsA和NbsB分别变更为基因型名称arcA和rfaD。
Two genetically distinct classes of novobiocin-supersensitive mutants were isolated from E. coli K-12. One class, given the phenotypic name NbsA, lies at 10 min on the E. coli chromosome. The order of the genes in this region, based on transductional analyses, is proC NbsA plsA purE. The second, NbsB, lies at 80 min. The order of the genes in this region, based on transduction analyses, is xyl cysE NbsB pyrE. Both classes of mutants show increased sensitivity to hydrophobic drugs, but are different: NbsA cells tend to be more sensitive to cationic agents, whereas NbsB cells show the opposite tendency. The sole detectable biochemical alteration in NbsA strain is greater than 90% reduction in the phosphate content of the lipid A region of the lipopolysaccharide. The NbsB mutation results in lipopolysaccharide that contains primarily the stereoisomer D-glycero-D-mannoheptose, rather than L-glycero-D-mannoheptose, rather than L-glycero-D-mannoheptose, and which contains very little of the distal sugars. Since NbsA strains have apparently normal outer membrane proteins and total cellular phospholipids, changes solely in lipopolysaccharide can increase permeability to certain hydrophobic antibiotics. Complementation studies indicate that the NbsA marker is probably allelic with acrA. The NbsB marker is genetically and phenotypically similar to the rfaD locus of Salmonella typhimurium. For this reason, the phenotypic designations NbsA and NbsB were changed to the genotypic designations arcA and rfaD, respectively.