Ref ID : 3766
Marie-Helene Bre, Jeffrey Diamond, and Roger Jacques; Factors Mediating the Vitamin B12 Requirement of Euglena. J.Protozool. 22(3):432-434, 1975
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Deprived of vitamin B12, Euglena gracilis strain Z ceases to divide which we believe to be a function of the light regime: division inhibition occurs more quickly in continuous light than in alternating (6L:6D) light and not at all in total darkness. This phenomenon is dependent on the carbon source; cells grown in glutamate-malate medium did not divide regardless of the culture conditions while DL-lactate as carbon source permits growth in darkness in the absence of B12. Conditions which lead to an increased O2 or decreased CO2 tension in medium, such as agitation in darkness or incubation in red or white light, result in inhibition of division. This inhibition can be reversed by re-transferring the cells to still culture in the dark or, in the case of light-induced blockage, by the addition of DCMU.