Perspectives in Environmental Toxicology

For decades, there has been an increasing concern about the potential hazards of ionizing and non-ionizing radiations on human health. This chapter provides several evidences related to pathophysiology of electromagnetic field (EMF) and its effects on different tissues and organs with special reference to neurophysiological and behavioral dysfunctions. Developing central nervous system (CNS) is extremely sensitive to EMF due to various factors especially due to presence of the high amount of water content, lipids and low amount of antioxidant enzymes. Therefore, the study is focused on the effects of radio frequency (RF) EMF and extremely low frequency magnetic field (ELF MF) on neurological disorders. The severity of effects always depends on exposure doses like, exposure duration, position of subjects, power density and field intensity, which could be measured in terms of specific absorption rate (SAR). There are several biomarkers, which are very useful to measure the radiation effects in both in vitro and in vivo model. The most intensely studied biomarkers by various researchers in CNS are protein kinase C, micronuclei, mitochondrial pathways, melatonin, calcium ion concentration, antioxidant enzymes like glutathione, superoxide dismutase, catalase etc. EMF may also lead to alterations in neurotransmission and consequently in cognitive and memory functions which are mainly linked to the brain hippocampus. Thus there are various histopathological aspects of hippocampus, which are studied and discussed in this chapter. Additionally, the dose response relationship between EMF and biological effects are discussed in this chapter.

It is widely accepted that non-ionizing electromagnetic fields are present in the environment and are alarming as a major pollutant or electro-pollutant for health risk. The present study aimed to investigate the protective measures of melatonin against exposure of microwave radiations. Study also explored the mechanistic correlation among microwave radiation, melatonin and biological effects by computational method. For this, 60-day-old male Wistar rats were divided into four groups (n = 4/group): sham exposed (control), Melatonin (Mel) treated (2 mg/kg), 2.45 GHz microwave (MWs) exposed and MWs + Mel treated. Exposure took place in Plexiglas cages for 2 h a day for 35 days where, power density (0.2 mW/cm²) and specific absorption rate (SAR-0.14 W/kg) were estimated. Results show that melatonin prevent oxidative damage biochemically by significant decrease (p < 001) the levels of lipid peroxide (LPO) and reactive oxygen species (ROS) in the brain. However, exposure of microwave individually shows significant changes in LPO and ROS level. The effective dose of melatonin was validated by in silico method and which reveals the interaction of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) Eenzmyes of Central Nervous System (CNS) with melatonin. Where, AChE showed better interaction with the binding energy of −9.01 kcal/mol and inhibition constant 3.11 uM by comparing with BuChE. These results concluded that the melatonin has strong antioxidative potential against microwave radiation, which could be achieved by an implementation of computational approach.

Nanotechnology has a global socioeconomic significance. On the brighter side, Nanoparticles (NPs) offer extraordinary technical competencies which allow them to perform enormously novel developments in science and industries. Whereas, on the darker side, just the same novel qualities of nanoparticles can concurrently evoke undesired features, which sometimes lead to adverse and harmful interactions with exposed organisms. Workers involved in manufacturing and handling of NPs in all countries face new hazards from these nanomaterials. The occupational safety and health associations have taken schemes to spot the gaps between awareness and practices. These international agencies formulate the guidelines for handling nano materials and fix their occupational exposure limits. In this chapter authors discussed the source and role of NPs in different areas, NPs induced toxicity, their interaction with different biomolecules, as well as the safety and handling guidelines of NPs in occupational and laboratory areas.

Environmental pollution has a concerned issue now days, increased continuously many fold in current years and has reached the levels, toxic for living things. Toxic heavy metals are the chemicals that more hazards for biological system. Some heavy metals are essential for life, but others like Cadmium (Cd), Hg, As and Pb are non-essential and dangerous for living organism. Cadmium is environmental and industrial pollutant, present in air, drinking water and in food, has several reports to health effect. Cadmium is a toxic heavy metal that accumulates in the body and produce serious illness. Yet being a toxic metal, it’s mechanism of toxicity remain unclear but generation of Reactive Oxygen species (ROS) identified as a main role in toxicity. Cadmium induce (ROS) level causes to damage to the organs of body; generate harmful effect and many diseases and also affect the apoptosis inducing factor, caspases and Bax overexpression. Apoptosis disorder are associated with many diseases, such as cancer, autoimmune disorder, and neurodegenerative disease. Chronic cadmium exposure causes several disease and morphological changes in body organs, induce the signalling pathway which caused generation of ROS.

Protein and DNA-advanced glycation end-products (DNA-AGEs) are toxic by-products of metabolism and are also assimilated by high temperature processed foods. AGEs may be generated rapidly or over long times stimulated by distinct triggering mechanisms, thereby accounting for their roles in multiple settings and disease states. Neurodegenerative diseases (NDDs) are associated with the misfolding and deposition of specific proteins, DNA adduct formation either intra or extra-cellularly in the nervous system. There is also evidence that brain tissue in patients with NDD is exposed to DNA oxidation and glycoxidation during the course of the disease. Although familial mutations play an important role in protein misfolding and aggregation, the majority of cases of NDD are sporadic, suggesting that other factors must contribute to the onset and progression of these disorders. High levels of refined and carbohydrate enriched diets, hyper caloric diets and sedentary lifestyles drive endogenous formation of AGEs via accumulation of highly reactive glycolysis intermediates and activation of the reductase pathway (polyol/aldose) producing high intracellular reducing sugars are the important modifiable environmental factors. Some of these modifications might affect proteins in detrimental ways and lead to their misfolding and accumulation. Reducing sugars play important roles in modifying proteins, forming AGEs in a non-enzymatic process named glycation. Several proteins linked to NDDs, such as amyloid β, tau, prions and transthyretin, were found to be glycated in patients, and this is thought to be associated with increased protein stability through the formation of crosslinks that stabilize protein aggregates causing NDDs like Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), familial amyloid polyneuropathy (FAP), and prion disease (PrD). Moreover, glycation may also be responsible, via the receptor for AGE (RAGE), for an increase in oxidative stress and inflammation through the formation of reactive oxygen species (ROS) and the induction of nuclear factor-κB (NF-κB). Here, we revised the role of protein and DNA-AGEs in the major NDDs and highlight the potential value of protein and DNA-AGEs glycation as a biomarker or target for therapeutic intervention. Additionally, the chapter covers several new therapeutic approaches that have been applied to treat these devastating disorders, including the use of various synthetic, natural and gold and silver conjugated nanoparticles (Au, Ag-NPs).

We have performed the interaction analysis of cigarette smoke carcinogens with the enzymes involved in DNA repair mechanisms. Cigarette smoke’s derivatives like 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) are well known carcinogens. The binding efficiency of carcinogens with enzymes obtained from docking methods were ranging from +36.96 to −7.47 kcal/mol. Binding efficiency was characterized for the enzymes sharing equivalent or better interaction as compared to positive control. Also we have analyzed the interaction pattern of NNK and NNAL with DNA. The present study suggests that NNK and NNAL may alter the DNA repair machinery that could initiate the progression of tumor leading to cancer. Computational method explores the toxicological characteristics of these enzymes and also opening an opportunity for researchers.

The Neisseria meningitides has overcome the several front line drugs, which inhibit penicillin binding protein synthesis and develop resistance or tolerance to these drugs. To overcome this situation, here we have attempted to reconstruct the metabolic network of peptidoglycan biosynthesis pathway of Neisseria meningitides, to obtain the potential drug target other than the penicillin binding proteins, as the biological networks like transcriptional, gene regulatory, metabolic or protein-protein interaction networks of organisms are widely studied, giving an insight into metabolism and regulation. The metabolic network was constructed based on the KEGG database, followed by graph spectral analysis of the network to identify hubs as well as sub-clustering of the reactions. Analysis of the eigen values and spectrum of the normalized laplacian matrix of the reaction pathway indicate the enzyme, murG transferase, catalyzing N-acetylglucosamine (GlcNAc) may considered as a potential drug target. As a case study, we have built a homology model of identified drug target murG transferase and various information have been generated through molecular dynamics, which will be useful in wetlab structure determination. The three-dimensional (3D) structure is essential for functional annotation and rational drug design. Accurate models are suitable for a wide range of applications, such as prediction of protein binding sites, prediction of the effect of protein mutations, and structure-guided virtual screening. The generated model can be further explored for insilico docking studies with suitable inhibitors.

India is the one among the major country in agricultural production and second largest producer after China and Brazil in rice and sugarcane production respectively. The cultivation of rice and plantation of sugarcane results in various types of residues: rice straw, rice husk and for sugarcane: bagasse, press mud or filter cake and molasses. During the harvesting of rice crop, the top portion grains are harvested and transported to the mill, while the stem (straw), rice husk, leaf and sugarcane residues are left on the field. It could be an appropriate to reuse and utilize a portion of crop residue for liquid fuels or combusted/gasified to produce electricity and heat. This chapter provides an overview of solid waste residues for energy production and also their toxic effects in the environment an open burning process. This chapter reviews the process for the production of ethanol, charcoal, paper and building materials (concrete, cement, bricks) from biomass. Additionally, a significant role of rice husk in silica production and then synthesized silicon nanoparticle use in biomedical research (i.e. drug delivery, cancer treatment etc.) has been introduced. Interestingly, the role of bio-computational approach of silica nanoparticle for drug designing also discussed. Comprehensive review processing of vermicomposting is discussed as a potential tool to bio-convert rice or sugarcane residues into enabling recycling of organic matter or organic fertilizer. After harvesting of rice or sugarcane, these residues remain on agriculture land and processed further for open burning by farmers. This open burning has hazardous effects on human health and the environment, is also discussed in this article. This article provides the possible pathway of mechanism and future recommendations for the use of agriculture waste as a bio-resource.

Antibiotics are the most effective group of antimicrobial drugs used for humans and veterinary therapy, but it is a rising trouble for the modern healthcare. However, the maximum use of antibiotics may be introducing the emergence and development of antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs), which increase the dissemination of resistance bacteria and genes in clinical and nonclinical environments. Horizontal gene transfer (HGT) and mobile genetic elements like plasmids, transposons and integrons are facilitating the environmental dissemination of the ARGs. The main source of antibiotics spreading is the uncontrolled uses of antibiotics, are not only used for the human therapy but it is widely used for the agricultural and livestock farming purposes. ARBs and ARGs have been extensively detected in wastewater, agricultural soil, animal manure and hospital waste, so that they must be consider as environment pollutant as well and that can contaminate the natural environment. This chapter gives an overview on the impact of antibiotics and antibiotics resistance genes as an environmental pollutant in different environment.

Complementing ecotoxicity testing, a biomarker approach is widely used in ecological risk assessment programs. Biomarkers provide information about early warning biological responses to one or several chemical pollutants and can be revealed in an organism or its products. Biochemical, morphological or behavioral parameters of living organisms can be set to biomarkers of exposure, effect or susceptibility or biomarkers of defense and damage. This concept is more developed within aquatic than terrestrial ecotoxicology and social hymenopterans insect (ants, bees, bumblebees, wasps and termites), which are already actively used as bioindicator species, can be furtherly studied for revealing novel sets of biomarkers. They can provide sufficient information about ecosystem health because social insects usually occupy high trophic levels and are important predators, pollinators, scavengers and ecological engineers. Social insect colonies stay in a certain place (except army ants), which makes them excellent model group for biomarker studies on ecotoxicological effects in nature. Despite their high ecological significance, wide spread distribution and sampling convenience, social insects are not intensively studied within biomonitoring programs and still not widely used as sentinel species. Revealing direct biological responses of social insects to toxic substances at the different levels of biological organization, systematization of scientific data and creating of simplified recommendations for practical biomonitoring purposes may facilitate progress in current terrestrial ecotoxicology.