Characterization of phe B gene encoding catechol 2,3-dioxygenase

A shaken thermal gradient device providing temperatures between 8.3 and 33.5° C was used to investigate the effects of silver ion on the duration of the lag phase and on minimum apparent growth temperatures of Hyphomicrobium spp. grown at 29 and 9°C. With 29°C-grown inocula, at lower temperatures, an increased time was required for growth initiation in the presence of silver ion added at 5 ng ml^-1. With silver ion added at 10 or 100 ng ml^-1, growth initiation was not observed at lower temperatures. With 100 ng ml^-1 added silver ion, this effect also was observed with 9°C-grown inocula. This increased sensitivity to silver ion could limit the ability of Hyphomicrobium spp., and possibly other microbes, to initiate growth and to contribute to microbial functioning in silver-impacted low temperature environments.