Differential proteomic analysis under pesticides stress and normal conditions in Bacillus cereus 2D

A potential pesticide degrading bacterial isolate (2D), showing maximum tolerance (450 mg∙L-1) for cypermethrin, fipronil, imidacloprid and sulfosulfuron was recovered from a pesticide contaminated agricultural field. The isolate degraded cypermethrin, imidacloprid, fipronil and sulfosulfuron in minimal salt medium with 94, 91, 89 and 86% respectively as revealed by high performance liquid chromatography (HPLC) and gas chromatography (GC) analysis after 15 days of incubation. Presence of cyclobutane, pyrrolidine, chloroacetic acid, formic acid and decyl ester as major intermediate metabolites of cypermethrin biodegradation was observed in gas chromatography mass spectrometry (GC-MS) analysis. Results based on 16S rDNA sequencing, and phylogenetic analysis showed maximum similarity of 2D with Bacillus cereus (Accession ID: MH341691). Stress responsive and catabolic/pesticide degrading proteins were over expressed in the presence of cypermethrin in bacteria. Enzymatic kinetics of laccase was deduced in the test isolate under normal and pesticide stress conditions which suggested that the production of enzyme was induced significantly in pesticide stress (163 μg.μL-1) as compare to normal conditions(29 μg.μL-1) while the Km value was decreased in pesticides stress condition (Km = 10.57 mM) and increases in normal condition (Km = 14.33 mM).Amplification of laccase gene showed a major band of 1200bp. The present study highlights on the potential of 2D bacterial strain i.e., high tolerance level of pesticide, effective biodegradation rate, and presence of laccase gene in bacterial strain 2D, could become a potential biological agent for large-scale treatment of mixture of pesticide (cypermethrin, fipronil, imidacloprid and sulfosulfuron) in natural environment (soil and water).

Combined Effects of Pesticides and Electromagnetic-Fields on Honeybees: Multi-Stress Exposure

Honeybee and general pollinator decline is extensively reported in many countries, adding new concern to the general biodiversity loss. Many studies were addressed to assess the causes of pollinator decline, concluding that in most cases multi-stress effects were the most probable ones. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions), were analyzed in the field. Three experimental sites were chosen: a control one far from direct anthropogenic stress sources, a pesticide-stress site and multi-stress one, adding to the same exposure to pesticides the presence of an electromagnetic field, coming from a high-voltage electric line. Experimental apiaries were monitored weekly for one year (from April 2017 to April 2018) by means of colony survival, queen activity, storage and brood amount, parasites and pathogens, and several biomarkers in young workers and pupae. Both exposure and effect biomarkers were analysed: among the first, acetylcholinesterase (AChE), catalase (CAT), glutathione S-transferase (GST) and alkaline phosphatase (ALP) and Reactive Oxygen Species (ROS); and among the last, DNA fragmentation (DNAFRAGM) and lipid peroxidation (LPO). Results showed that bee health conditions were the worst in the multi-stress site with only one colony alive out of the four ones present at the beginning. In this site, a complex picture of adverse effects was observed, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The overall results clearly indicate that the multi-stress conditions were able to induce biochemical, physiological and behavioral alterations which severely threatened bee colony survival.

Ecological Performance of Multifunctional Pesticide Tolerant Strains of Mesorhizobium Sp. In Chickpea With Recommended Pendimethalin, Ready-mix of Pendimethalin and Imazethpyr, Carbendazim and Chlorpyrifos Application

The present study was designed to screen the Mesorhizobium strains (50) for tolerance in four recommended pesticides for chickpea. It was followed by in-vitro development of robust pesticide tolerant strains by growth in pesticides amended media over several generations. Further, verification of the multifunctional traits of pesticide tolerant mesorhizobia under pesticide stress was conducted in-vitro. Among different pesticides, significantly high tolerance in Mesorhizobium strains was observed with recommended doses of pendimethalin (37%) and ready-mix (36%) followed by chlorpyrifos (31%) and carbendazim (30%), on an overall basis. Based on multifunctional traits, Mesorhizobium strains viz. MR2, MR17 and recommended MR33 were the most promising. Ecological performance of the potential Mesorhizobium strains alone and in dual-inoculation with recommended PGP rhizobacterium strain RB-1 (Pseudomonas argenttinensis JX239745.1) was further analyzed in field following standard pesticide application in PBG-7 and GPF-2 chickpea varieties for two consecutive rabi seasons (2015 and 2016). Dual-inoculant treatments; recommended RB-1+MR33 (4.1%) and RB-1+MR2 (3.8%) significantly increased the grain yield over Mesorhizobium alone treatments viz MR33 and MR2, respectively. Grain yield in PBG7 variety was significantly affected (7.3%) by the microbial inoculant treatments over GPF2 variety. Therefore, the potential pesticide tolerant strains MR2 and MR33 can be further explored as compatible dual-inoculants with recommended RB-1 for chickpea under environmentally stressed conditions (pesticide application) at multiple locations. Our approach using robust multifunctional pesticide tolerant Mesorhizobium for bio-augmentation of chickpea with might be helpful in the formulation of effective bio-inoculants consortia in establishing successful chickpea–Mesorhizobium symbiosis.

NITROGEN AND PHOSPHORUS METABOLISM OF ANABAENA DOLIOLUM UNDER UV-B AND PESTICIDE STRESS

The effects of UV-B and pesticides (Butachlor and Carbofuran) on nitrogen and phosphorus metabolism have been studied on filamentous, nitrogen-fixing cyanobacterium, Anabaena doliolum. The study showed a decrease in the uptake of NH4+, PO4-3, activities of nitrogenase, glutamine synthetase, and alkaline phosphatase, when the cells were exposed to UV-B and pesticides. The interaction of two stresses showed the additive type of behavior for the studied parameters. In contrast, a significant increase in NO3- uptake and nitrate reductase activity was seen when Anabaena cells were exposed to different doses of UV-B.

Overexpression of Some Stress Tolerance Genes Confers Enhanced Pesticide Tolerance in 5-Aminolevulinic Acid Treated Bean Seedlings

Overdose of pesticides leads to a decrease in yield and quality of plants such as bean. The unconscious use of deltamethrin, one of the synthetic insecticides, increases the amount of reactive oxygen species (ROS) by causing oxidative stress in plants. In this case, plants tolerate to stress by activating the antioxidant defense mechanism and many genes. 5-Aminolevulinic acid (ALA) improves tolerance to stress by external administration in low doses. There are many gene families that are effective in the regulation of this mechanism. In addition, one of the response mechanisms at the molecular level against environmental stressors in plants is retrotransposon movements. In this study, the expression levels of SOD, GPX, CAT and SAP genes were determined by Q-PCR in deltamethrin (0.5 ppm) and various doses (20, 40 and 80 mg/l) of ALA treated bean seedlings. It was determined that while deltamethrin increased the expression of these genes, 20 and 40 mg/l ALA gradually increased the expression of genes at levels close to control, but 80 mg/l ALA increased almost the same level as deltamethrin. In addition, REMAP was performed to determine the polymorphism caused by retrotransposon movements. While deltamethrin treatment has caused to decrease of genomic template stability (GTS), ALA treatments have prevented this decline. Collectively, these findings demonstrated that ALA gives the utility for alleviating pesticide stress effects on bean.

Molecular Evolution and Characterization of Fish Stathmin Genes

Stathmin is a highly conserved microtubule remodeling protein, involved in many biological processes such as signal transduction, cell proliferation, neurogenesis and so on. However, little evolutional information has been reported about this gene family in fish. In this study, 175 stathmin genes were identified in 27 species of fish. Conserved exon-intron structure and motif distributions were found in each group. Divergence of duplicated genes implied the species’ adaptation to the environment. Functional divergence suggested that the evolution of stathmin is mainly influenced by purifying selection, and some residues may undergo positive selection. Moreover, synteny relationship near the stathmin locus was relatively conserved in some fish. Network analyses also exhibited 74 interactions, implying functional diversity. The expression pattern of some stathmin genes was also investigated under pesticide stress. These will provide useful references for their functional research in the future.

Comparative Analysis of the aquaporin Gene Family in 12 Fish Species

Aquaporins (Aqps) are a class of water channel proteins that play key roles in many physiological functions and cellular processes. Here, we analyzed 166 putative Aqp genes in 12 fish species and divided them into four groups. Gene organization and motif distribution analyses suggested potentially conserved functions in each group. Several recombination events were identified in some members, which accelerate their divergence in evolution. Furthermore, a few positive selection sites were identified, and mutations at these sites could alter the stability of Aqp proteins. In addition, expression profiles of some Aqp genes under pathogen infection and organophosphorus pesticide stress were also investigated. The result implied that several Aqp genes may affect different immune responses and osmoregulation. This study provides a comparative analysis of the fish Aqp gene family to facilitate further functional analyses.

Responses of Plants to Pesticide Toxicity: an Overview

ABSTRACT: Pesticides are applied all over the world to protect plants from pests. However, their application also causes toxicity to plants, which negatively affects the growth and development of plants. Pesticide toxicity results in reduction of chlorophyll and protein contents, accompanied by decreased photosynthetic efficiency of plants. Pesticide stress also generates reactive oxygen species which causes oxidative stress to plants. To attenuate the negative effects of oxidative stress, the antioxidative defense system of plants gets activated, and it includes enzymatic antioxidants as well as non-enzymatic antioxidants. The present review gives an overview of various physiological responses of plants under pesticide toxicity in tabulated form.