Multiphasic uptake of D-glucose by an oligotrophic marine bacterium

Abstract
Uptake of D-glucose in the range 2.5 .times. 10-9 to 4.0 .times. 10-3 M by an oligotrophic marine bacterium, LNB-155, could be represented by 4 phases of a single, multiphasic mechanism. Other kinetic models did not give a good fit. Sharp transitions occurred at .apprx. 1.6 .times. 10-6, 10-5 and 2 .times. 10-4 M. Values for Km and Vmax increased regularly upon transition to higher phases. Multiphasic uptake mechanisms in LNB-155 indicate adaptation to living in environments with fluctuating levels of D-glucose. These observations are consistent with the hypothesis that pelagic marine bacteria experience considerable fluctuations in nutrient concentration in their microenvironment.