Thiamine limitation determines the transition from aerobic to fermentative-like metabolism in Rhizobium etli CE3.
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::miniTn5lacZ1 thiamine auxotroph subjected to the above subcultures resulted in growth arrest, reduced pyruvate-dehydrogenase activity, and a smaller amount of poly-beta-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.
Taboada
Hermenegildo
H
Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
Encarnación
Sergio
S
Vargas
María del Carmen
Mdel C
Mora
Yolanda
Y
Miranda-Ríos
Juan
J
Soberón
Mario
M
Mora
Jaime
J
D000332:Aerobiosis / Q000502:physiology; D001426:Bacterial Proteins / Q000096:biosynthesis; D001710:Biotin / Q000378:metabolism; D005285:Fermentation / Q000502:physiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006885:Hydroxybutyrates / Q000032:analysis; D016254:Mutagenesis, Insertional; D011091:Polyesters / Q000032:analysis; D042163:Rhizobium etli / Q000737:chemistry / Q000254:growth & development / Q000502:physiology*; D013831:Thiamine / Q000235:genetics / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
D001426:Bacterial Proteins; D001710:Biotin; D006885:Hydroxybutyrates; D011091:Polyesters; D013831:Thiamine; C105797:ThiC protein, Bacteria; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates