In Vitro Anti-tb Activity Of Kanglemycin And Resistance To Rice Blast Agricultural Antibiotic Screening Strategy

Kanglemycin A is a novel ansamycin group antibiotic. Its producing strain,Nocardia Mediterranei subsp. Kanglensis 1747-64 was isolated from soil collectedfrom the Kang-Le area, Guangdong province, P. R. China. Two novel groupantibiotics have been found till now. One of them is ansamycin group antibioticincluding kanglemycin A and kanglemycin D. kanglemycin A has similar chemicalstructure with rifampicin, the first front anti-TB drug used in clinic.To evaluate anti-TB activity of kanglemycin A, Susceptibility testing ofKanglemycin A in vitro to 20 strains including Mycobacteria smegmatis (ATCC14468)Mycobacteria tuberculosis H₃₇Rv (ATCC27294), Mycobacteria tuberculosis H₃₇Ra(ATCC25177), clinical isolated ofloxacin (OFLX)-sensitive Mycobacteria tuberculosis andofloxacin-resistant Mycobacteria tuberculosis was carded out by equivalent serial dilutionmethod in 10ml glass tubes in Sauton medium. MICs values showed kanglemycin A hasstrong inhibitory activity against Mycobacteria tuberculosis and ofloxacin-resistantMycobacteria tuberculosis. Comparison of MICs value between kanglemycin A andrifampicin showed inhibitory activity of kanglemycin A to standard strains and(OFLX)-sensitive strains of Mycobacteria tuberculosis was weaker than that of rifampicin,but to ofloxacin-resistant Mycobacteria tuberculosis, inhibitory activity ofkanglemycin A was strong than that of rifampicin.The preliminary bioactive studies of kanglemycin A showed kanglemycin A isa potential anti-TB candidate and laid fundamental basis on its development towardsanti-TB reagent. This section focused on set up screening model and combinational strategy tofind anti-fungal agricultural antibiotics, especially anti-Pyricularia grisea antibioticsusing traditional bioautograpHy assay, 96 well microplate observations of myceliummorphology and UV spectra in PAD-HPLC online analysis. Based on agar diffusiontest, mycelium deformations and inhibition of spore growth, 5 positive strains withstrong bioactivities against Pyricularia grisea: strain 2639,3236,3352,3356,3431were screened from more than 1600 strains coming from different antibioticproducing sources. After dereplication of polyene, the high toxic group of antibioticsby quick-, micro-, early-, spectroscopic identification by characteristic ultravioletabsorptive peak in PAD-HPLC, the cultured broth of strain 3431 was studied bychromatography such as silica gel, sephadex LH-20 and HPLC. Bioactive componentof 3431-1 as main bioactive component was purified and prove to be non-polyeneantibiotic, more NMR data analysis is under way.