Dataset Information

Molecular stress responses to nano-sized zero-valent iron (nZVI) particles in the soil bacterium Pseudomonas stutzeri.

ABSTRACT: Nanotoxicological studies were performed in vitro using the common soil bacterium Pseudomonas stutzeri to assess the potentially toxic impact of commercial nano-sized zero-valent iron (nZVI) particles, which are currently used for environmental remediation projects. The phenotypic response of P. stutzeri to nZVI toxicity includes an initial insult to the cell wall, as evidenced by TEM micrographs. Transcriptional analyses using genes of particular relevance in cellular activity revealed that no significant changes occurred among the relative expression ratios of narG, nirS, pykA or gyrA following nZVI exposure; however, a significant increase in katB expression was indicative of nZVI-induced oxidative stress in P. stutzeri. A proteomic approach identified two major defence mechanisms that occurred in response to nZVI exposure: a downregulation of membrane proteins and an upregulation of proteins involved in reducing intracellular oxidative stress. These biomarkers served as early indicators of nZVI response in this soil bacterium, and may provide relevant information for environmental hazard assessment.

SUBMITTER: Sacca ML

PROVIDER: S-EPMC3934913 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Molecular stress responses to nano-sized zero-valent iron (nZVI) particles in the soil bacterium Pseudomonas stutzeri.

Saccà Maria Ludovica ML Fajardo Carmen C Martinez-Gomariz Montserrat M Costa Gonzalo G Nande Mar M Martin Margarita M

PloS one 20140225 2

Nanotoxicological studies were performed in vitro using the common soil bacterium Pseudomonas stutzeri to assess the potentially toxic impact of commercial nano-sized zero-valent iron (nZVI) particles, which are currently used for environmental remediation projects. The phenotypic response of P. stutzeri to nZVI toxicity includes an initial insult to the cell wall, as evidenced by TEM micrographs. Transcriptional analyses using genes of particular relevance in cellular activity revealed that no ...[more]

PMID: 24586957

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Project description:Toxic and persistent contaminants in groundwater are technologically difficult to remediate. Remediation techniques using nanoparticles (NPs) such as nZVI (Zero-Valent Iron) are applicable as in situ reduction or oxidation agents and give promising results for groundwater treatment. However, these NP may also represent an additional contamination in groundwater. The aims of this study are to assess the impact of nZVI on the nitrate-reducing potential, the abundance and the structure of a planktonic nitrate-reducing bacterial community sampled in groundwater from a multicontaminated site. An active nitrate-reducing bacterial community was obtained from groundwater samples, and inoculated into batch reactors containing a carbon substrate, nitrate and a range of nZVI concentrations (from 0 to 70.1 mg Fe.L-1). Physical (pH, redox potential), chemical ( NO3- concentrations) and biological (DNA, RNA) parameters were monitored during 1 week, as well as nZVI size distribution and mortality of bacteria. Nitrate-reducing activity was temporally stopped in the presence of nZVI at concentrations higher than 30 mg L-1, and bacterial molecular parameters all decreased before resuming to initial values 48 h after nZVI addition. Bacterial community composition was also modified in all cultures exposed to nZVI as shown by CE-SSCP fingerprints. Surprisingly, it appeared overall that bacteria viability was lower for lower nZVI concentrations. This is possibly due to the presence of larger, less reactive NP aggregates for higher nZVI concentrations, which inhibit bacterial activity but could limit cell mortality. After 1 week, the bacterial cultures were transplanted into fresh media without nZVI, to assess their resilience in terms of activity. A lag-phase, corresponding to an adaptation phase of the community, was observed during this step before nitrate reduction reiterated, demonstrating the community's resilience. The induction by nZVI of modifications in the bacterial community composition and thus in its metabolic potentials, if also occurring on site, could affect groundwater functioning on the long term following nZVI application. Further work dedicated to the study of nZVI impact on bacterial community directly on site is needed to assess a potential impact on groundwater functioning following nZVI application.

Project description:In recent decades, nano-scale zero valent iron is reported to have plant growth enhancement capacity under laboratory conditions, but till date, there is no report to highlight its effect on the growth and yield of field-grown plants. In this study, we have evaluated the potential of nZVI priming on rice yield. A two-year field study has been conducted with different concentrations (10, 20, 40, and 80 mg l-1) of nZVI for seed priming. The efficacy of nanopriming was compared with the hydroprimed control set. Seeds were treated for 72 h and sown in nursery beds and after 30 days seedlings were transplanted in the field. Root anatomy and morphology were studied in 7 days old seedlings where no changes were found. RAPD analysis also confirmed that low doses of nZVI were not genotoxic. Nanoprimed plants also had broader leaves, higher growth, biomass, and tiller number than control plants. Maximum yield was obtained from the 20 mg l-1 nZVI primed set (3.8 fold higher than untreated control) which is achieved primarily because of the increase in fertile tiller numbers (two fold higher than untreated control). Higher values of other agronomic parameters like growth rate, net assimilation rate proved that nZVI priming enhanced photosynthetic efficiency and helped in the proper storage of photo-assimilates. All these attributed to increased accumulation of phytochemicals like starch, soluble sugar, protein, lipid, phenol, riboflavin, thiamine, and ascorbic acid in the grains. The elemental analysis confirmed that nZVI priming also promoted higher accumulations of macro and micronutrients in grains. Thus, nanoprimed seeds showed better crop performance compared to the traditional hydropimed seeds. Hence, nZVI can be considered as 'pro-fertilizer' and can be used commercially as a seed treatment agent which is capable of boosting plant growth and yield along with minimum interference to the soil ecosystem.Supplementary informationThe online version contains supplementary material available at 10.1007/s00344-021-10335-0.

Dataset Information

Molecular stress responses to nano-sized zero-valent iron (nZVI) particles in the soil bacterium Pseudomonas stutzeri.

Publications

Molecular stress responses to nano-sized zero-valent iron (nZVI) particles in the soil bacterium Pseudomonas stutzeri.

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