Informatics Publishing Limited

Pallavi Kaushik ¹, Neha Rawat ¹, Megha Mathur ¹, Priyanka Raghuvanshi ¹, Pradeep Bhatnagar ¹, Harimohan Swarnkar ², Swaran Flora ²

Affiliations
1 Department of Life Sciences, The IIS University, Jaipur-302020, IN
2 Division of Pharmacology and Toxicology, Defence Research & Development Establishment, Gwalior - 474 002, IN

Abstract

Arsenic-contaminated areas of Sanganer, Jaipur, Rajasthan, India were surveyed for the presence of metal resistant bacteria contaminated with textile effluent. Samples were collected from soil receiving regular effluent from the textile industries located at Sanganer area. The properties like pH, electrical conductivity, organic carbon, organic matter, exchangeable calcium, water holding capacity and metals like arsenic, iron, magnesium, lead and zinc were estimated in the contaminated soil. In total, nine bacterial strains were isolated which exhibited minimum inhibitory concentration (MIC) of arsenic ranging between 23.09 and 69.2mM. Four out of nine arsenic contaminated soil samples exhibited the presence of arsenite hyper-tolerant bacteria. Four high arsenite tolerant bacteria were characterized by 16S rDNA gene sequencing which revealed their similarity to Microbacterium paraoxydans strain 3109, Microbacterium paraoxydans strain CF36, Microbacterium sp. CQ0110Y, Microbacterium sp. GE1017. The above results were confirmed as per Bergey’s Manual of Determinative Bacteriology. All the four Microbacterium strains were found to be resistant to 100μg/ml concentration of cobalt, nickel, zinc, chromium selenium and stannous and also exhibited variable sensitivity to mercury, cadmium, lead and antimony. These results indicate that the arsenic polluted soil harbors arsenite hyper-tolerant bacteria like Microbacterium which might play a role in bioremediation of the soil.

Keywords

Arsenic, bacteria, hyper-tolerance, metal-resistant

Full Text

     

Leena Khurana ¹, Payal Chaturvedi ¹, Charu Sharma ¹, Pradeep Bhatnagar ¹, Nidhi Gupta ²

Affiliations
1 Department of Biotechnology, IIS (Deemed to be University), Jaipur - 302020, Rajasthan, IN
2 Department of Biotechnology, IIS (Deemed to be University), Jaipur - 302020, Rajastha, IN

Abstract

The neonicotinoid class of insecticide is nicotine-like neuro-toxicants used to control the pests of agriculture crops and ornamental plants. They act as selective agonists of acetylcholine receptors in the central nervous system of insect pests and work by disrupting their nerve impulses. Some of the properties of this class of insecticides are a long half-life in soil, low volatility, and higher water solubility, leading to their accumulation in soil, underground water, and water bodies due to surface runoff. This, in turn, results in exposure to many beneficial non-target aquatic and soil fauna such as arthropods, fish, birds, mammals, etc. Although it has a selective mode of action for insects, some in vivo and in vitro investigations have also shown toxicity in non-target invertebrates and vertebrates. Initially, neonicotinoid toxicity was observed in honey bees, which are essential pollinators of crops. Later, studies reported the accumulation of neonicotinoid residues leading to the mortality of aquatic fauna, including salt marsh and freshwater mosquitoes, brine shrimp, fleas, and crayfish. Imidacloprid exposure led to disruption of larval development in the Mayfly larvae. Also, earthworms that play a crucial role in enhancing soil fertility were drastically affected by acetamiprid, clothianidin, imidacloprid, nitenpyram, and thiacloprid. Apart from these, toxicological impacts were also observed in vertebrates such as birds, where imidacloprid, clothianidin, acetamiprid, and thiacloprid caused reproductive, metabolic, and morphological alterations. Similarly, imidacloprid and acetamiprid caused gills, brain and liver dysfunction with embryo mortality. Even after the selective action of neonicotinoids, instances of mammalian toxicity were also reported in many in vivo studies. DNA damage and liver dysfunctions due to imidacloprid in rabbits were observed in various studies. In a recent study, imidacloprid exposure led to DNA damage and oxidative stress in bone marrow-derived mesenchymal cells of buffalo. Also, many instances of neurotoxicity, reproductive toxicity, immunotoxicity, genotoxicity and cytotoxicity in mouse and rat models were observed due to different neonicotinoids. Many in vitro studies using mammalian cell lines have also established potential risks of neonicotinoid exposure. This review, therefore, is a compilation of various toxicity studies of different types of neonicotinoid pesticides in both nontarget invertebrates and vertebrates, including several kinds of toxicities caused in mammals with neonicotinoid exposure.

Keywords

Insecticide, Invertebrates, Pesticide, Toxicity, Vertebrates.

Full Text