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Factors Mediating the Vitamin B 12 Requirement of Euglena
Author(s) -
BRÉ MARIEHÉLÈNE,
DIAMOND JEFFREY,
JACQUES ROGER
Publication year - 1975
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1975.tb05200.x
Subject(s) - darkness , euglena , euglena gracilis , dcmu , white light , biophysics , incubation , botany , biology , biochemistry , chemistry , optics , photosynthesis , physics , gene , photosystem ii , chloroplast
SYNOPSIS. Deprived of vitamin B 12 , 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 do not divide regardless of the culture conditions while dl ‐lactate as carbon source permits growth in darkness in the absence of B 12 . Conditions which lead to an increased O 2 or decreased CO 2 tension in the 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.