Detection of antistaphylococcal and toxic compounds by biological assay systems developed with a reporter Staphylococcus aureus strain harboring a heat inducible promoter - lacZ transcriptional fusion.
Previously it was reported that promoter of groES-groEL operon of Staphylococcus aureus is induced by various cell-wall active antibiotics. In order to exploit the above promoter for identifying novel antistaphylococcal drugs, we have cloned the promoter containing region (P(g)) of groES-groEL operon of S. aureus Newman and found that the above promoter is induced by sublethal concentrations of many antibiotics including cell-wall active antibiotics. A reporter S. aureus RN4220 strain (designated SAU006) was constructed by inserting the P(g)-lacZ transcriptional fusion into its chromosome. Agarose-based assay developed with SAU006 shows that P(g) in single-copy is also induced distinctly by different classes of antibiotics. Data indicate that ciprofloxacin, rifampicin, ampicillin, and cephalothin are strong inducers, whereas, tetracycline, streptomycin and vancomycin induce the above promoter weakly. Sublethal concentrations of ciprofloxacin and ampicilin even have induced P(g) efficiently in microtiter plate grown SAU006. Additional studies show for the first time that above promoter is also induced weakly by arsenate salt and hydrogen peroxide. Taken together, we suggest that our simple and sensitive assay systems with SAU006 could be utilized for screening and detecting not only novel antistaphylococcal compounds but also different toxic chemicals.
Department of Biochemistry, Bose Institute, P1/12-CIT Scheme VII M, Calcutta 700 054, India.
Palas Kumar
PK
Chanda
Tridib
T
Ganguly
Malabika
M
Das
Chia Yen
CY
Lee
Thanh T
TT
Luong
Subrata
S
Sau
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001149:Arsenates / Q000494:pharmacology; D001483:Base Sequence; D001681:Biological Assay / Q000379:methods; D018835:Chaperonin 10 / Q000235:genetics; D018834:Chaperonin 60 / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D050939:Gene Fusion; D005798:Genes, Bacterial / Q000187:drug effects; D017930:Genes, Reporter; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007763:Lac Operon; D008826:Microbial Sensitivity Tests / Q000379:methods; D009876:Operon; D011401:Promoter Regions, Genetic / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics*
D000900:Anti-Bacterial Agents; D001149:Arsenates; D018835:Chaperonin 10; D018834:Chaperonin 60; D017931:DNA Primers; D006861:Hydrogen Peroxide