Open AccessThe role of glucose in the Kluyveromyces bulgaricus flocculation phenomenon: transduction by cAMP‐dependent protein kinase pathway?
Author(s) -
Géhin Gérald,
Bonaly Roger,
Coulon Joël
Publication year - 2001
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2001.tb10846.x
Subject(s) - flocculation , kluyveromyces , cycloheximide , biochemistry , galactose , yeast , biology , protein kinase a , signal transduction , enzyme , chemistry , saccharomyces cerevisiae , protein biosynthesis , organic chemistry
Yeast flocculation appears to be dependent on several culture conditions such as nitrogen or carbon sources. In 0.2% glucose medium Kluyveromyces bulgaricus flocculation intensity is weak (10% at maximum) by comparison with flocculation in 2% glucose medium (85% maximum). Addition of glucose to K. bulgaricus in exponential growth phase in 0.2% glucose medium produced a rapid increase of the flocculation percentage during the 30 min following the addition of glucose. cAMP and 2,4‐dinitrophenol showed similar effects while cAMP‐dependent protein kinase (PKA) inhibitors exhibited an antagonist effect. Moreover, the induction of flocculation did not seem to imply translation of new proteins: cycloheximide had no effect, although growth was inhibited. The induction of flocculation mainly implies ATP hydrolysis for activation or secretion of galactose‐specific receptors as demonstrated by treatment with NaN 3 . We propose a hypothesis that involves a PKA transduction signal leading to flocculation.