Abstract
The effects of 0·2 m validamycin A in reducing internode length (the distance between adjacent branches on a hypha) and colony radial growth rate of Rhizoctonia cerealis were antagonized by some carbon sources (cellobiose, fructose, glucose, lactose, maltose, mannose and sucrose) but not by others (acetate, casamino acids, citrate, galactose, gluconate, glucuronate, glycerol, l -arabinose, mannitol, melibiose, ribose, sorbitol, and xylitol). Antagonism of the effects of the antibiotic by 5 m m sucrose and cellobiose (but not 5 m m fructose, glucose, lactose, maltose or mannose) from the onset of inoculation was correlated with the production by the fungus of extracellular invertase and cellobiase activities. The addition of 3- O -methyl- d -glucose to medium containing 5 m m glucose increased the sensitivity of R. cerealis to the antibiotic, suggesting that antagonism of validamycin A by glucose was dependent on the sugar being metabolized, rather than the sugar inhibiting uptake of the antibiotic. The onset of the response of the fungus to validamycin A appeared to be related to the length of time of exposure to the antibiotic, and mycelium grown on medium containing antibiotic continued to display the ‘inhibited’ phenotype even after growing for several hours on medium lacking antibiotic.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.