Differential expression of proteins and genes in the lag phase of Lactococcus lactis subsp. lactis grown in synthetic medium and reconstituted skim milk.
We investigated protein and gene expression in the lag phase of Lactococcus lactis subsp. lactis CNRZ 157 and compared it to the exponential and stationary phases. By means of two-dimensional polyacrylamide gel electrophoresis, 28 highly expressed lag-phase proteins, implicated in nucleotide metabolism, glycolysis, stress response, translation, transcription, cell division, amino acid metabolism, and coenzyme synthesis, were identified. Among the identified proteins, >2-fold induction and down-regulation in the lag phase were determined for 12 proteins in respect to the exponential phase and for 18 proteins in respect to the stationary phase. Transcriptional changes of the lag-phase proteins in L. lactis were studied by oligonucleotide microarrays. Good correlation between protein and gene expression studies was demonstrated for several differentially expressed proteins, including nucleotide biosynthetic enzymes, adenylosuccinate synthase (PurA), IMP dehydrogenase (GuaB), and aspartate carbamoyl transferase (PyrB); heat-shock protein DnaK; serine hydroxymethyl transferase (GlyA); carbon catabolite control protein (CcpA); elongation factor G (FusA); and cell division protein (FtsZ).
Larsen
Nadja
N
Department of Dairy and Food Science, The Royal Veterinary and Agricultural University, Rolighedsvej 30, D-1958 Frederiksberg C, Denmark. nf@kvl.dk
Boye
Mette
M
Siegumfeldt
Henrik
H
Jakobsen
Mogens
M
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D003470:Culture Media; D015180:Electrophoresis, Gel, Two-Dimensional; D005285:Fermentation; D015870:Gene Expression; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D008892:Milk; D020411:Oligonucleotide Array Sequence Analysis
D001426:Bacterial Proteins; D003470:Culture Media