Higher plant photosystem II light-harvesting antenna, not the reaction center, determines the excited-state lifetime-both the maximum and the nonphotochemically quenched.
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Construction of the octose 8-phosphate intermediate in lincomycin A biosynthesis: characterization of the reactions catalyzed by LmbR and LmbN.
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In vitro activity of clindamycin and other antimicrobials against gram-positive bacteria and Hemophilus influenzae.
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SUMMARY: Seven antimicrobials--clindamycin, penicillin, ampicillin, cloxacillin, erythromycin, lincomycin and cephalexin--were found to have a high degree of activity in vitro against 256 isolates of gram-positive bacteria and Hemophilus influenzae. Clindamycin was clearly superior against staphylococci and 3.12 mug/ml or less of clindamycin inhibited all 35 isolates of H. influenzae. Synergism was not demonstrated when clindamycin was tested in combination with sulfisoxazole or sulfamethoxazole by either the agar dilution or 24-hour growth curve method. This was true for penicillin as well, and the effect was independent of sulfonamide sensitivity. The erythromycin-sulfonamide combination was synergistic against 6 of 10 strains studied by the growth curve method; this effect was not demonstrable by the agar dilution method. (+info)
In vitro susceptibility of Mycoplasma hyopneumoniae field isolates and occurrence of fluoroquinolone, macrolides and lincomycin resistance.
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A total of 159 Thai isolates of Mycoplasma hyopneumoniae isolated from pneumonic lungs of pigs during 2006-2011 were investigated for their in vitro susceptibility to 12 antimicrobial agents. Low activity of chlortetracycline was indicated by the MIC range from 3.12-100 mug/ml and MIC90 of 50 mug/ml. Seventy-six isolates showed resistance to enrofloxacin, whereas 2 isolates showed resistance to macrolides and lincomycin. In addition, a point mutation at A2058G was revealed by sequence analysis of 23S ribosomal RNA in both isolates. The present results confirmed the rapid increase of resistant M. hyopneumoniae isolates against chlortetracycline, enrofloxacin, macrolides and lincomycin in Thailand. Selection of drugs to control swine diseases in Thailand must be done more prudently in consideration of reducing the antimicrobial resistance. (+info)
Cloning of a lincosamide resistance determinant from Streptomyces caelestis, the producer of celesticetin, and characterization of the resistance mechanism.
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Self-resistance has been investigated in Streptomyces caelestis (producer of the lincosamide antibiotic celesticetin), from which a lincosamide resistance determinant (clr) has been isolated on a 1-kilobase DNA fragment and cloned in Streptomyces lividans. The clr product is a specific methylase which produces a single residue of N6-monomethyladenine in 23S rRNA at position 2058, thereby rendering the 50S ribosmal subunit resistant to the action of lincosamides. (+info)