Isolation and characterization of the dew cluster from the piezophilic deep-sea bacterium Shewanella violacea

The dew cluster of genes involved in cell division and cell wall synthesis from the piezophilic deep-sea bacterium Shewanella violacea was isolated and characterized. It comprises 15 open reading frames, of which the organization is mraZ-mraW-ftsL-ftsI-murE-murF-mraY-murD-ftsW-murG-murC-ftsQ-ftsA-ftsZ-envA, in that order. To analyze transcription upstream from the ftsZ gene, Northern blot and primer extension analyses were performed. The results showed that gene expression is not pressure dependent. Western blot analysis showed that the FtsZ protein is equally expressed under several pressure conditions in the range of atmospheric (0.1 MPa) to high (50 mPa) pressures. Using immunofluorescence microscopy, the FtsZ ring was observed in the center of cells at pressure conditions of 0.1 to 50 mPa. These results imply that the FtsZ protein function is not affected by elevated pressure in this piezophilic bacterium.