The mechanism of phenotypically altered SM resistance in mutants of Escherichia coli JC5455 (Rldrd-19Km-) lrs and JC5455 (pON5300) was compared with that of the standard strain JC5455 (Rldrd-19Km-). On analyzing the membrane polypeptides in polyacrylamide gel both mutants were found to possess a protein spectrum different from that of ths standard strain. Transport of D-xylose and L-arginine was the same in all strains, transport of L-proline was decreased in JC5455 (pON5300) which may indicate a mutational interference with energy metabolism. The basic uptake of dihydrostreptomycin was the same in all strains but there were differences after preincubation of cells with streptomycin or glucose. The increased resistance of JC5455 (Rldrd-19Km-) lrs may be due to observed quantitative differences in membrane polypeptides that might play a role in the binding and functional expression of aminoglycoside-3'adenylyl transferase which modifies streptomycin. The increased sensitivity toward streptomycin in JC5455 (pON5300) can be explained by a mutation due to N-methyl-N'-nitro-N-nitrosoguanidine in the host cell since this change of sensitivity to streptomycin could not be transferred by transformation into a nonmutagenized strain. The coincidence of inducibility of increased transport of streptomycin by this antibiotic and the altered frequency of reversion to high levels of streptomycin resistance in JC5455 (pON5300) and in the transformant JC5455 (pON5302) may indicate that the altered reversibility toward phenotypically high resistance to streptomycin is a property of pON5300 and is transferred by transformation.

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J Bacteriol. 1970 Nov;104(2):882-9 PubMed

Plasmid. 1978 Sep;1(4):584-8 PubMed

Nature. 1970 Aug 15;227(5259):680-5 PubMed

Antimicrob Agents Chemother. 1979 Feb;15(2):177-81 PubMed

J Bacteriol. 1973 Nov;116(2):1064-6 PubMed

J Bacteriol. 1976 Sep;127(3):1529-37 PubMed

Biochim Biophys Acta. 1975 Apr 2;383(4):457-63 PubMed

Antimicrob Agents Chemother. 1976 Jun;9(6):928-38 PubMed

Folia Microbiol (Praha). 1979;24(2):136-42 PubMed

Gene. 1979 May;6(1):23-8 PubMed

Folia Microbiol (Praha). 1977;22(3):198-205 PubMed

Plasmid. 1977 Nov;1(1):1-7 PubMed

Annu Rev Microbiol. 1978;32:469-518 PubMed

Genetics. 1973 May;74(1):17-31 PubMed

Folia Microbiol (Praha). 1973;18(3):257-62 PubMed

Antimicrob Agents Chemother. 1977 Aug;12(2):163-77 PubMed

J Bacteriol. 1979 Jan;137(1):661-3 PubMed

Mol Gen Genet. 1978 Nov 29;167(2):119-27 PubMed

J Bacteriol. 1970 Nov;104(2):890-901 PubMed

General and molecular microbiology and microbial genetics in the IM CAS