Interaction and nanotoxic effect of ZnO and Ag nanoparticles on mesophilic and halophilic bacterial cells
The toxicity of two commonly used nanoparticles, silver and zinc oxide on mesophilic and halophilic bacterial cells has been investigated. Enterobacter sp., Marinobacter sp., Bacillus subtilis, halophilic bacterium sp. EMB4, were taken as model systems. The nanotoxicity was more pronounced on Gram negative bacteria. ZnO nanoparticles reduced the growth of Enterobacter sp. by 50%, while 80% reduction was observed in halophilic Marinobacter sp. In case of halophiles, this may be attributed to higher content of negatively charged cardiolipins on their cell surface. Interestingly, bulk ZnO exerted minimal reduction in growth. Ag nanoparticles were similarly cytotoxic. Nanotoxicity towards Gram positive cells was significantly less, possibly due to presence of thicker peptidoglycan layer. The bacterium nanoparticle interactions were probed by electron microscopy and energy dispersive X-ray analysis. The results indicated electrostatic interactions between nanoparticles and cell surface as the primary step towards nanotoxicity, followed by cell morphological changes, increase in membrane permeability and their accumulation in the cytoplasm.
[Show abstract] [Hide abstract] ABSTRACT: Nanotechnology has seen exponential growth in last decade due to its unique physicochemical properties; however, the risk associated with this emerging technology has withdrawn ample attention in the past decade. Nanotoxicity is majorly contributed to the small size and large surface area of nanomaterials, which allow easy dispersion and invasion of anatomical barriers in human body. Unique physio-chemical properties of NPs make the investigation of their toxic consequences intricate and challenging. This makes it important to have an in-depth knowledge of different mechanisms involved in nanomaterials's action as well as toxicity. Nano-toxicity has various effects on human health and diseases as they can easily enter into the humans via different routes, mainly respiratory, dermal and gastrointestinalroutes. This also limits the use of nanomaterials as therapeutic and diagnostic tools. This review focuses on the nanomaterial-cell interactions leading to toxicological responses. Different mechanisms involved in nanoparticle-mediated toxicity with the main focus on oxidative stress, genotoxic and carcinogenic potential has also been discussed. Different methods and techniques used for the characterization of nanomaterials in food and other biological matrices have also been discussed in detail. Nano-toxicity on different organs - with the major focus on the cardiac and respiratory system - have been discussed. Conclusively, the risk management of nanotoxicity is also summarized. This review provides a better understanding of the current scenario of the nanotoxicology, disease progression due to nanomaterials, and their use in the food industry and medical therapeutics. Briefly, the required rules, regulations and the need of policy makers has been discussed critically.0Comments 1Citation
- "In prokaryotic cells, silver and zinc oxide NPs electrostatically interacts with the bacterial cell surface and causes toxicity. Such interactions also result in morphological and mitochondrial alterations as well as cytoplasmic accumulation of NPs within the cells (Sinha et al., 2011). On the other hand, eukaryotic semi-permeable plasma membrane selectively permits few important nano-sized molecules across the lipid membrane either by specific membranetransport protein channels or by endocytosis (Alberts et al., 1997; Conner and Schmid, 2003). "
[Show abstract] [Hide abstract] ABSTRACT: The aim of this paper is to present characteristics, toxicity and environmental behavior of nanoparticles (NPs) (silver, copper, gold, zinc oxide, titanium dioxide, iron oxide) that most frequently occur in consumer products. In addition, NPs are addressed as the new aquatic environmental pollutant of the 21st century. NPs are adsorbed onto particles in the aquatic systems (clay minerals, fulvic and humic acids), or they can adsorb environmental pollutants (heavy metal ions, organic compounds). Nanosilver (nAg) is released from consumer products into the aquatic environment. It can threaten aquatic organisms with high toxicity. Interestingly, copper nanoparticles (Cu-NPs) demonstrate higher toxicity to bacteria and aquatic microorganisms than those of nanosilver nAg. Their small size and reactivity can cause penetration into the tissues and interfere with the metabolic systems of living organisms and bacterial biogeochemical cycles. The behavior of NPs is not fully recognized. Nevertheless, it is known that NPs can agglomerate, bind with ions (chlorides, sulphates, phosphates) or organic compounds. They can also be bound or immobilized by slurry. The NPs behavior depends on process conditions, i.e. pH, ionic strength, temperature and presence of other chemical compounds. It is unknown how NPs behave in the aquatic environment. Therefore, the research on this problem should be carried out under different process conditions. As for the toxicity, it is important to understand where the differences in the research results come from. As NPs have an impact on not only aquatic organisms but also human health and life, it is necessary to recognize their toxic doses and know standards/regulations that determine the permissible concentrations of NPs in the environment.0Comments 0Citations
- "Ag-NPs can also be used as water disinfectant due to their strong biocidal effect observed in organisms such as Escherichia coli (Choi et al. 2008, Cho et al. 2005, Sondi and Salopek-Sondi 2004, Wang et al. 2012, Radziga et al. 2013), Staphylococcus aureus (Choi et al. 2008), Caenorhabditis elegans (), Marinobacter sp. (Sinha et al. 2011), Lemna minor (Gubbins et al. 2011), Bacillus subtilis (Lee et al. 2009, Wang et al. 2012), Saccharomyces cerevisiae, Trichosporon beigellii, Candida albicans (Kim et al. 2009), Ceriodaphnia dubia (Glover and Wood 2004), Daphnia magna (Glover and Wood 2004, Jo et al. 2012, Bianchini et al. 2005, Blinova et al. 2013), Thamnocephalus platyurus(Blinova et al. 2013), Agrobacterium tumefaciens (Wang et al. 2012), and Pseudomonas aeruginosa, and Serratia proteamaculans (Radziga et al. 2013). In the study (Hebeish 2011), the 50 ppm nAg concentration used to impregnate textiles showed 96% inhibition of the bacterial growth for E. coli and S. aureus. "
[Show abstract] [Hide abstract] ABSTRACT: The effect of surface or lattice modification of nanoparticles (NPs) on terrestrial plants is poorly understood. We investigated the impact of different zinc oxide (ZnO) NPs on green pea (Pisum sativum L.), one of the highest consumed legumes globally. Pea plants were grown for 65 d in soil amended with commercially available bare ZnO NPs (10 nm), 2 wt% alumina doped (Al2O3@ZnO NPs, 15 nm), or 1 wt% aminopropyltriethoxysilane coated NPs (KH550@ZnO NP, 20 nm) at 250 and 1000 mg NP/kg soil inside a greenhouse. Bulk (ZnO) and ionic Zn (zinc chloride) were included as controls. Plant fresh and dry biomass, changes in leaf pigment concentrations, elements (Zn, Al, Si), and protein and carbohydrate profile of green pees were quantified upon harvest at 65 days. With the exception of the coated 1000 mg/kg NP treatment, fresh and dry weight were unaffected by Zn exposure. Although, all treated plants showed higher tissue Zn than controls, those exposed to Al2O3@ZnO NPs at 1000 mg/kg had greater Zn concentration in roots and seeds, compared to bulk Zn and the other NP treatments, keeping Al and Si uptake largely unaffected. Higher Zn accumulation in green pea seeds were resulted in coated ZnO at 250 mg/kg treatments. In leaves, Al2O3@ZnO NP at 250 mg/kg significantly increased Chl-a and carotenoid concentrations relative to the bulk, ionic, and the other NP treatments. The protein and carbohydrate profiles remained largely unaltered across all treatments with the exception of Al2O3@ZnO NPs at 1000 mg/kg where sucrose concentration of green peas increased significantly, which is likely a biomarker of stress. Importantly, these findings demonstrate that lattice and surface modification can significantly alter the fate and phytotoxic effects of ZnO NPs in food crops and seed nutritional quality. To the authors' knowledge, this is the first report of a life cycle study on comparative toxicity of bare, coated, and doped ZnO NPs on a soil-grown food crop.1Comment 0Citations
- "For example, growth can be negatively affected by ENPs exposure (Lin and Xing, 2007; Sinha et al., 2011; Bandyopadhyay et al., 2012a,b; Gaiser et al., 2012; Hawthorne et al., 2012; Mukherjee et al., 2014b; Rico et al., 2014). There are several reports on the toxicity of different ENPs on food crops (Lin and Xing, 2007; Lee et al., 2008; Navarro et al., 2008; Sinha et al., 2011; Bandyopadhyay et al., 2012a,b; Gaiser et al., 2012; Hawthorne et al., 2012; Zhao et al., 2013a Zhao et al., , 2014a Rico et al., 2014; Mukherjee et al., 2014a,b). However, a mechanistic understanding of the impact of ENPs on edible/crop plants is needed for accurate exposure and risk assessment, but this knowledge remains elusive. "