Garcia-Riestra C, Perlin M H, Lerner S A
Antimicrob Agents Chemother. 1985 Jan;27(1):114-9. doi: 10.1128/AAC.27.1.114.
Accumulation of purified adenylylated dihydrostreptomycin (DHS-AMP) was examined in two strains of Escherichia coli. E. coli JSRO-N was plasmid free and aminoglycoside (AG) susceptible; E. coli JSRO-N(pSAD1) contained a plasmid-encoded AG adenylyltransferase which modifies DHS and streptomycin and confers resistance to both of these drugs. Although both whole cells and spheroplasts of JSRO-N accumulated free DHS, we were not able to demonstrate uptake of DHS-AMP by this strain. Whole cells and spheroplasts of JSRO-N(pSAD1) accumulated DHS at a much slower rate than that observed in JSRO-N. This was presumably due to the activity of the adenylyltransferase in JSRO-N(pSAD1). However, this low rate of accumulation of DHS was still higher than the uptake of DHS-AMP by either JSRO-N or JSRO-N(pSAD1). Thus, the rate of accumulation of DHS-AMP was even lower than that of DHS during the slow, initial, energy-dependent phase of AG uptake seen in JSRO-N(pSAD1). We also found that when either JSRO-N or JSRO-N(pSAD1) was incubated with barely inhibitory or subinhibitory concentrations of DHS, rapid uptake of DHS could be stimulated by the addition of an inhibitory concentration of another AG, such as amikacin. Uptake of DHS-AMP could not be similarly enhanced by the addition of amikacin. Our results indicate that DHS-AMP is not accumulated by whole cells or spheroplasts of E. coli. These results are consistent with the postulated intracellular location of AG-modifying enzymes.
在两株大肠杆菌中检测了纯化的腺苷酸化双氢链霉素（DHS - AMP）的积累情况。大肠杆菌JSRO - N不含质粒且对氨基糖苷类（AG）敏感；大肠杆菌JSRO - N(pSAD1)含有一个质粒编码的AG腺苷酸转移酶，该酶可修饰DHS和链霉素，并赋予对这两种药物的抗性。尽管JSRO - N的全细胞和原生质体都积累了游离的DHS，但我们无法证明该菌株摄取了DHS - AMP。JSRO - N(pSAD1)的全细胞和原生质体积累DHS的速度比在JSRO - N中观察到的要慢得多。这可能是由于JSRO - N(pSAD1)中腺苷酸转移酶的活性所致。然而，这种较低的DHS积累速率仍高于JSRO - N或JSRO - N(pSAD1)对DHS - AMP的摄取。因此，在JSRO - N(pSAD1)中AG摄取的缓慢、初始、能量依赖阶段，DHS - AMP的积累速率甚至低于DHS。我们还发现，当JSRO - N或JSRO - N(pSAD1)与几乎抑制或亚抑制浓度的DHS一起孵育时，添加抑制浓度的另一种AG（如阿米卡星）可以刺激DHS的快速摄取。添加阿米卡星不能类似地增强DHS - AMP的摄取。我们的结果表明，大肠杆菌的全细胞或原生质体不会积累DHS - AMP。这些结果与AG修饰酶假定的细胞内定位一致。
