Lycopersicum esculentum (Faisal et al. 2013). The presence of nCeO 2 NPs in
concentrations of 62.5, 125, 250, and 500 mgÁL
-1 induced generation of ROS and
oxidative damage in O. sativa (Rico et al. 2013a, b; Siddiqui et al. 2015). TiO 2 NPs at
concentrations of 10 and 30 ppm modified the activities of enzymatic antioxidants in
Phaseolus vulgaris (Jacob et al. 2013). Further, reduced GSH was found under
quantum dot exposure at a concentration of 5.8 μM in A. thaliana (Navarro et al.
2012), while higher ascorbic acid levels were induced in Asparagus officinalis under
treatment with AgNPs (An et al. 2008).
Moreover, according to Wei and Wang (2013), nanoparticles exhibit antioxidant
capacity in their own right and mimic the activity of natural antioxidative enzymes.
The following nanoparticles exhibit enzyme-like activities: CeO 2 NPs, PtNPs, and
fullerenes demonstrate properties similar to superoxide dismutase; CeO 2 NPs,
Fe 3 O 4 NPs, and Co 3 O 4 NPs mimic catalase; CeO 2 NPs, Fe 3 O 4 NPs, Co 3 O 4 NPs,
MnO 2 NPs, CuONPs, and AuNPs exhibit peroxidase-like activity.
The presence of numerous NPs at some concentrations demonstrates detrimental
effects on plants altering not only their morphological, physiological, and biochemical traits but also their genotoxic traits (Panda et al. 2011). NPs enter plants by
various pathways, by targeting the genes or DNA of particular organelles and
through the transporters (Sahebi et al. 2015; Siddiqui et al. 2015). When NPs enter
the cell, a whole range of macromolecular interactions begins. It has been found that
AgNPs change the expression of the matrix metalloproteinases, tumor necrosis
factor (TNF), and interleukin (IL) -12 and IL-1 genes (Bhol and Schechter 2005).
In addition to this, Kaveh et al. (2013) observed that, in Arabidopsis, AgNPs
upregulated the expression of genes that are related to the response to metals and
oxidative stress but downregulated the expression of genes involved in the response
to pathogens, i.e., systemic acquired resistance (SAR) and hormonal signals. Furthermore, another study showed that AgNPs induce the expression of genes involved
in ABA signaling and auxin-responsive genes as IAA8 (Arase et al. 2012). Genes
downregulated in response to NPs were primarily related to cell organization and
biogenesis (Atha et al. 2012; Landa et al. 2012). It was shown that carbon nanotubes
modify the DNA structure in plant tissues. Multiwalled carbon nanotubes
(MWCNTs) caused chromosomal aberrations in the roots of Allium cepa, which
affected the expression of genes involved in cell division and apoptosis (Ghosh et al.
2011). In turn, the proximity of single-walled carbon nanotubes (SWCNT) to DNA
led to the unzipping of the strands, impairing the normal matching of the nucleobases
in rice DNA (Katti et al. 2015).
NPs showing biocidal properties against pathogens may also be toxic to positive
microorganisms. The activity of NPs depends on many parameters: shape, size, the
limiting or stabilizing agent, and reduction method used (type of reducing agent used
in production) and surface charge (Pal et al. 2007; Carlson et al. 2008; Choi et al.
2009; Jiang et al. 2009; Kvitek et al. 2009; Badawy et al. 2010, 2011; Abbaszadegan
et al. 2015; Kujda et al. 2015; Rana and Kalaichelvan 2011). The mechanisms most
frequently involved in the toxic effects shown by NPs are damage to cell
membranes, generation of ROSs, and genotoxicity (Jampilek and Kralova 2015).
In the case of bacteria, AuNPs can modify their cell membrane; interfere with the
1 Nanotechnology in Agriculture, the Food Sector, and Remediation: Prospects,. . .
19
concentrations of 62.5, 125, 250, and 500 mgÁL
-1 induced generation of ROS and
oxidative damage in O. sativa (Rico et al. 2013a, b; Siddiqui et al. 2015). TiO 2 NPs at
concentrations of 10 and 30 ppm modified the activities of enzymatic antioxidants in
Phaseolus vulgaris (Jacob et al. 2013). Further, reduced GSH was found under
quantum dot exposure at a concentration of 5.8 μM in A. thaliana (Navarro et al.
2012), while higher ascorbic acid levels were induced in Asparagus officinalis under
treatment with AgNPs (An et al. 2008).
Moreover, according to Wei and Wang (2013), nanoparticles exhibit antioxidant
capacity in their own right and mimic the activity of natural antioxidative enzymes.
The following nanoparticles exhibit enzyme-like activities: CeO 2 NPs, PtNPs, and
fullerenes demonstrate properties similar to superoxide dismutase; CeO 2 NPs,
Fe 3 O 4 NPs, and Co 3 O 4 NPs mimic catalase; CeO 2 NPs, Fe 3 O 4 NPs, Co 3 O 4 NPs,
MnO 2 NPs, CuONPs, and AuNPs exhibit peroxidase-like activity.
The presence of numerous NPs at some concentrations demonstrates detrimental
effects on plants altering not only their morphological, physiological, and biochemical traits but also their genotoxic traits (Panda et al. 2011). NPs enter plants by
various pathways, by targeting the genes or DNA of particular organelles and
through the transporters (Sahebi et al. 2015; Siddiqui et al. 2015). When NPs enter
the cell, a whole range of macromolecular interactions begins. It has been found that
AgNPs change the expression of the matrix metalloproteinases, tumor necrosis
factor (TNF), and interleukin (IL) -12 and IL-1 genes (Bhol and Schechter 2005).
In addition to this, Kaveh et al. (2013) observed that, in Arabidopsis, AgNPs
upregulated the expression of genes that are related to the response to metals and
oxidative stress but downregulated the expression of genes involved in the response
to pathogens, i.e., systemic acquired resistance (SAR) and hormonal signals. Furthermore, another study showed that AgNPs induce the expression of genes involved
in ABA signaling and auxin-responsive genes as IAA8 (Arase et al. 2012). Genes
downregulated in response to NPs were primarily related to cell organization and
biogenesis (Atha et al. 2012; Landa et al. 2012). It was shown that carbon nanotubes
modify the DNA structure in plant tissues. Multiwalled carbon nanotubes
(MWCNTs) caused chromosomal aberrations in the roots of Allium cepa, which
affected the expression of genes involved in cell division and apoptosis (Ghosh et al.
2011). In turn, the proximity of single-walled carbon nanotubes (SWCNT) to DNA
led to the unzipping of the strands, impairing the normal matching of the nucleobases
in rice DNA (Katti et al. 2015).
NPs showing biocidal properties against pathogens may also be toxic to positive
microorganisms. The activity of NPs depends on many parameters: shape, size, the
limiting or stabilizing agent, and reduction method used (type of reducing agent used
in production) and surface charge (Pal et al. 2007; Carlson et al. 2008; Choi et al.
2009; Jiang et al. 2009; Kvitek et al. 2009; Badawy et al. 2010, 2011; Abbaszadegan
et al. 2015; Kujda et al. 2015; Rana and Kalaichelvan 2011). The mechanisms most
frequently involved in the toxic effects shown by NPs are damage to cell
membranes, generation of ROSs, and genotoxicity (Jampilek and Kralova 2015).
In the case of bacteria, AuNPs can modify their cell membrane; interfere with the
1 Nanotechnology in Agriculture, the Food Sector, and Remediation: Prospects,. . .
19