Pseudomonas putida KT2440 response to nickel or cobalt induced stress by quantitative proteomics

Abstract

Nickel and cobalt are obligate nutrients for the gammaproteobacteria but when present at high concentrations they display toxic effects. These two metals are present in the environment, their origin being either from natural sources or from industrial use. In this study, the effect of inhibitory concentrations of Ni or Co was assessed on the soil bacterium Pseudomonas putida KT2440 using a proteomic approach. The identification of more than 400 spots resulted in the quantification of 160 proteins that underwent significant variations in cells exposed to Co and Ni. This analysis allowed us to depict the cellular response of P. putida cells toward metallic stress. More precisely, the parallel comparison of the two proteomes showed distinct responses of P. putida to Ni or Co toxicity. The most striking effect of Co was revealed by the accumulation of several proteins involved in the defense against oxidative damage, which include proteins involved in the detoxification of the reactive oxygen species, superoxides and peroxides. The up-regulation of the genes encoding these enzymes was confirmed using qRT-PCR. Interestingly, in the Ni-treated samples, sodB, encoding superoxide dismutase, was up-regulated, indicating the apparition of superoxide radicals due to the presence of Ni. However, the most striking effect of Ni was the accumulation of several proteins involved in the synthesis of amino acids. The measurement of the amount of amino acids in Ni-treated cells revealed a strong accumulation of glutamate.

Ni exposure impacts the pool of free Fe and modifies DNA supercoiling via metal-induced oxidative stress in Escherichia coli K-12

“…A previous study in Pseudomonas putida employed proteomics to identify the production of superoxide and the accumulation of enzymes involved in the synthesis of amino acids as a hallmark of Ni toxicity (14). However, proteome studies often provide only a limited perspective because it is difficult to analyse scarce or hydrophobic proteins.…”

Metabolic adaptation and trophic strategies of soil bacteria—C1- metabolism and sulfur chemolithotrophy in Starkeya novella

“…Although several proteomic studies of soil bacteria, their interactions with plants and their responses to a variety of environmental stresses (e.g., heavy metals) have been carried out (Hansmeier et al, 2006; Cheng et al, 2010; Ray et al, 2013; Van Dijl and Hecker, 2013), the interplay between different growth modes associated with carbon and sulfur metabolism have not previously been investigated in a free living soil bacterium despite their significance for global element cycles and the speciation of carbon and sulfur compounds in the environment.…”

Rare earth element (REE)-dependent growth of Pseudomonas putida KT2440 depends on the ABC-transporter PedA1A2BC and is influenced by iron availability

“…The regulatory mechanisms for metal homeostasis of P. putida cells in response to other essential metal ions such as Co, Cu, Mg, Mo, Ni, and Zn are less well explored. Genes encoding for transport systems associated with the uptake and efflux of these metals can, however, be found in its genome (Belda et al, 2016; Nelson et al, 2002), and some of these have been studied in more detail (Miller et al, 2009; Ray et al, 2013).…”