Open AccessThiamine limitation determines the transition from aerobic to fermentative‐like metabolism in Rhizobium etli CE3
Author(s) -
Taboada Hermenegildo,
Encarnación Sergio,
Vargas María del Carmen,
Mora Yolanda,
MirandaRíos Juan,
Soberón Mario,
Mora Jaime
Publication year - 2008
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.1574-6968.2007.01006.x
Subject(s) - thiamine , auxotrophy , biochemistry , metabolism , strain (injury) , biology , thiamine pyrophosphate , fermentation , chemistry , cofactor , gene , enzyme , anatomy , mutant
Both thiamine and biotin when added to minimal medium subcultures reversed the fermentative‐like metabolism exhibited by Rhizobium etli CE3. Thiamine auxotrophs lacking thiCOGE genes were used to investigate the role of thiamine in this medium. A thiC1169∷ miniTn 5lacZ1 thiamine auxotroph subjected to the above subcultures resulted in growth arrest, reduced pyruvate‐dehydrogenase activity, and a smaller amount of poly‐β‐hydroxybutyrate compared with the CE3 strain. Moreover, thiC and thiEb genes were overexpressed as result of thiamine limitation. The absence of classical thi genes suggests that thiamine is synthesized with low efficiency by an alternative pathway. Low levels of thiamine cause the CE3 strain to exhibit a fermentative‐like metabolism.