Characterizing the production of a wild-type and benomyl-resistant Fusarium lateritium for biocontrol of Eutypa lata on grapevine.

Benomyl-resistant (BR) and wild-type (WT) strains of Fusarium lateritium were examined for their tolerance to benomyl on potato dextrose agar (PDA) containing benomyl and control of the Eutypa lata in grapevine bioassays. The WT strain grew on PDA containing 1 microg/ml benomyl at 13, 26 and 29 degrees C. The BR strain grew on PDA containing 10 microg/ml benomyl at 4 degrees C, on PDA containing 100 microg/ml benomyl at 29 degrees C, and on PDA containing 1,000 microg/ml benomyl at 13 degrees C and 26 degrees C. The BR strain was also able to colonize grapevine segments and control E. lata in the presence of 1,000 microg/ml benomyl. Both strains were amenable to production via liquid fermentation and both achieved 100% control of E. lata in grapevine bioassays. Neither the duration of fermentation nor incubation temperature during grapevine bioassays influenced the efficacy of either strain against E. lata. The results suggest that application of BR F. lateritium alone or in combination with benomyl may provide good control of E. lata.

Activity losses among T4 lysozyme charge variants after adsorption to colloidal silica.

Enzyme structure and function depend to some extent on enzyme net charge and charge location. Altering the charge of even a single residue may affect the interaction between enzyme and substrate such that all catalytic activity is lost. In this study we investigated the effect of net charge and charge location on the enzymatic activity of synthetic mutants of bacteriophage T4 lysozyme in the presence of colloidal silica. Enzymatic activity decreased upon adsorption, and these changes were variant-specific. Results were interpreted with reference to differences in adsorbed enzyme structure and orientation, and electrostatic effects. By exploring the effects of enzyme charge on adsorption, it may be possible to gain a better understanding of how enzyme structure influences adsorption and function at an interface.