title: Thiamine limitation determines the transition from aerobic to fermentative-like metabolism in Rhizobium etli CE3.
abstract: 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.
authors.affiliation: Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
authors.forename: Hermenegildo
authors.initials: H
authors.lastname: Taboada
authors.forename: Sergio
authors.initials: S
authors.lastname: Encarnación
authors.forename: María del Carmen
authors.initials: Mdel C
authors.lastname: Vargas
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Mora
authors.forename: Juan
authors.initials: J
authors.lastname: Miranda-Ríos
authors.forename: Mario
authors.initials: M
authors.lastname: Soberón
authors.forename: Jaime
authors.initials: J
authors.lastname: Mora
mesh_terms: 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
chemical_list: D001426:Bacterial Proteins; D001710:Biotin; D006885:Hydroxybutyrates; D011091:Polyesters; D013831:Thiamine; C105797:ThiC protein, Bacteria; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates