Premium
UPTAKE OF GUANINE BY THE DIATOM, PHAEODACTYLUM TRICORNUTUM 1
Author(s) -
Shah N.,
Syrett P. J.
Publication year - 1982
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1982.tb03224.x
Subject(s) - phaeodactylum tricornutum , guanine , biology , ammonium , photosynthesis , cycloheximide , biochemistry , nitrate , kinetics , metabolism , nitrogen , botany , algae , chemistry , ecology , nucleotide , protein biosynthesis , physics , organic chemistry , quantum mechanics , gene
Nitrate‐cultured cells of Phaeodactylum tricornutum Bohlin lack the ability to take up guanine but can do so after a period of nitrogen deprivation, i.e. photosynthesis in nitrogen‐free medium. Maximum rate of uptake occurred after 24 h of nitrogen deprivation. The development of ability to take up guanine required CO 2 fixation and was prevented by cycloheximide, ammonium or nitrate. The guanine taken up accummulated in the cells almost entirely as a compound which is probably methylated hypoxanthine. Guanine uptake was dependent upon metabolism and exhibited Michaelis‐Menten like kinetics with a half‐saturation value of 0.48 ± 0.05 μM guanine and a maximum uptake rate for guanine of ca. 200 nmol · 10 −8 cells · h −1 . Rate of uptake increased hyperbolically with Na + concentration, with 8.25 mM Na + supporting half‐maximal rate, and it was inhibited by K + ions.