The effect of cold stress on the proteome of the marine bacteriumPseudomonas fluorescens BA3SM1 and its ability to copewith metal excess

This study examined the effect of cold stress on the proteome and metal tolerance of Pseudomonas fluo-rescens BA3SM1, a marine strain isolated from tidal flat sediments. When cold stress (+10◦C for 36 h)was applied before moderate metal stress (0.4 mM Cd, 0.6 mM Cd, 1.5 mM Zn, and 1.5 mM Cu), growthdisturbances induced by metal, in comparison with respective controls, were reduced for Cd and Znwhile they were pronounced for Cu. This marine strain was able to respond to cold stress through a num-ber of changes in protein regulation. Analysis of the predicted differentially expressed protein functionsdemonstrated that some mechanisms developed under cold stress were similar to those developed inresponse to Cd, Zn, and Cu. Therefore, pre-cold stress could help this strain to better counteract toxicityof moderate concentrations of some metals. P. fluorescens BA3SM1 was able to remove up to 404.3 mgCd/g dry weight, 172.5 mg Zn/g dry weight, and 11.3 mg Cu/g dry weight and its metal biosorption abilityseemed to be related to the bacterial growth phase. Thus, P. fluorescens BA3SM1 appears as a promisingagent for bioremediation processes, even at low temperatures.