Effects of certain cadmium species on pure and litter populations of microorganisms.
Cadmium inhibition of microorganisms was found to be bacterial and chemical species dependent. E. coli inhibition was a function of the cadmium-ion concentration irregardless of the presence of citrate, a chelator for cadmium that it could not metabolize. Whereas with a Pseudomonas sp. able to metabolize citrate, cadmium inhibition was a function of both the cadmium ion and the presence of citrate. With no citrate, inhibition of this organism occurred only at relatively high cadmium-ion concentrations (above 10(-4) M); when citrate was added to the same cadmium-containing growth medium, inhibition was observed at a 1000 times lower cadmium-ion concentration (i.e., 10(-7) M). This observation is contrary to the classical understanding where a chelate reduces the toxic form of a metal allowing increased growth of the organism. The species of cadmium also differentially inhibited the Douglas fir letter respiration and nitrogen-fixing community activities.
D002104:Cadmium / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000378:metabolism; D002482:Cellulose; D002951:Citrates / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects* / Q000378:metabolism; D009586:Nitrogen Fixation; D010710:Phosphates / Q000378:metabolism; D011549:Pseudomonas / Q000187:drug effects* / Q000378:metabolism; D012988:Soil Microbiology; D013045:Species Specificity
D002951:Citrates; D010710:Phosphates; D002104:Cadmium; D002245:Carbon Dioxide; D002482:Cellulose