Role of Integrated Biomarker Response Tool for Assessment of Naphthalene Toxicity in Anabas testudineus

Thermo-chemical behaviour of Dunaliella salina biomass and valorising their biochar for naphthalene removal from aqueous rural environment

Thermo-chemical behavior of a microalgal biomass; Dunaliella salina was investigated through thermo-gravimetric analyses. Fully-grown D. salina biomass were subjected for biochar conversion using pyrolytic treatment at three distinct heating rates such as 2.5, 5, and 15 °C min-1. The kinetic appraisals were explained by using model-free kinetics viz., Kissinger-Akahira-Sanose, Flynn-Waal-Ozawa and Starink iso-conversional correlations with concomitant evaluation of activation energies (Ea). The Ea value is 194.2 kJ mol-1 at 90% conversion in FWO model, which is higher as compared to other two models. Moisture, volatile substances, and other biochemical components of the biomass were volatilized between 400 and 1000 K in two separate thermo-chemical breakdown regimes. Microscopic and surface characterization analyses were carried out to elucidate the elemental and morphological characteristics of the biomass and biochar. Further, the proficiency of the prepared biochar was tested for removing naphthalene from the watery media. The novelty of the present study lies in extending the applicability of biochar prepared from D. salina for the removal of a model polyaromatic hydrocarbon, naphthalene.

Neurodevelopmental toxicity and molecular mechanism of environmental concentration of tetrabromobisphenol A bis (2- hydroxyethyl) ether exposure to sexually developing male SD rats

Tetrabromobisphenol A bis (2- hydroxyethyl) ether (TBBPA-DHEE), as one of the main derivatives of Tetrabromobisphenol A, been attracted attention for its health risks. In this study, the neurotoxicity, mechanism, and susceptivity of TBBPA-DHEE exposure to sexually developing male rats were systematically studied. Neurobehavioral research showed that TBBPA-DHEE exposure could significantly affect the behavior, learning,and memory abilities of male-developing rats, and aggravate their depression. TBBPA-DHEE exposure could inhibit the secretion of neurotransmitters. Transcriptomics studies show that TBBPA-DHEE can significantly affect gene expression, and a total of 334 differentially expressed genes are enriched. GO function enrichment analysis shows that TBBPA-DHEE exposure can significantly affect the expression of genes related to synapses and cell components. KEGG function enrichment analysis shows that TBBPA-DHEE exposure can significantly affect the expression of signal pathways related to nerves, nerve development, and signal transduction. Susceptibility analysis showed that female rats were more susceptible to TBBPA-DHEE exposure than male rats. Therefore, TBBPA-DHEE exposure has neurodevelopmental toxicity to male developmental rats, and female developmental rats are more susceptible than male developmental rats. Its possible molecular mechanism is that TBBPA-DHEE may inhibit the secretion of neurotransmitters and affect signal pathways related to neurodevelopment and signal transduction.

Single and combined effects of caffeine and salicylic acid on mussel Mytilus galloprovincialis: Changes at histomorphological, molecular and biochemical levels

Caffeine (CAF) and salicylic acid (SA) are frequently detected in waterbody, though information on their biological impact is poor. This work assesses the effects of CAF (5ng/L to 10µg/L) and SA (0.05µg/L to 100µg/L) alone and combined as CAF+SA (5ng/L+0.05µg/L to 10µg/L+100µg/L) on mussel Mytilus galloprovincialis under 12-days exposure by histomorphology of digestive gland and oxidative stress defense at molecular and biochemical levels. Besides evaluating tissue accumulation, absence of histomorphological damage and haemocyte infiltration highlighted activation of defensive mechanisms. Up-regulation of Cu/Zn-sod, Mn-sod, cat and gst combined with increased catalase and glutathione S-transferase activity were found in CAF-exposed mussels, while SA reduced ROS production and mitochondrial activity. CAF+SA exposure induced differential responses, and the integrated biomarker response (IBR) revealed more pronounced effects of SA than CAF. These results enlarge knowledge on pharmaceuticals impact on non-target organisms, emphasizing the need for proper environmental risk assessment.

Naphthalene and its Derivatives: Efficient Fluorescence Probes for Detecting and Imaging Purposes

Naphthalene, white crystalline solid having polycyclic aromatic hydrocarbon with characteristic mothball order is naturally present in crucial oils of various plants. Naphthalene derivatives are extensive drug resources and are use as wetting agents, surfactants and as insecticides. These derivatives exhibit unique photo physical and chemical properties. These characteristics make them the most studied group of organic compounds. Naphthalene dyes have rigid plane and large π-electron conjugation. Therefor they have high quantum yield and excellent photostability. Naphthalene based fluorescence probes due to hydrophobic nature exhibit excellent sensing and selectivity properties towards anions and cations and also used as a part of target biomolecules. In conjugated probe system, introducing naphthalene moiety caused improvement in photo-stability. Therefore among various conjugated framework, naphthalene derivatives are considered excellent candidate for the construction of organic electronic appliances. These derivatives are useful for a variety of applications owing to their strong fluorescence, electroactivity and photostability. This article is based upon investigation of photophysical properties of naphthalene derivatives and fluorescence detecting probe of naphthalene. For photophysical properties the techniques under investigation are UV visible spectroscopy and fluorescence spectroscopy. Concentration dependent spectra and solvatochromic shifts on UV visible spectra are also part of discussion.

Histopathological and Biochemical Changes in the Gills of Anabas testudineus on Exposure to Polycyclic Aromatic Hydrocarbon Naphthalene

Naphthalene, a polycyclic aromatic hydrocarbon, is generated by various distillation, petroleum, and coal-tar production units and is used worldwide as mothballs, soil fumigants, and toilet deodorants. Considering the susceptibility of aquatic animals to different types of stressors in several water bodies, this study was carried out to evaluate the impact of naphthalene on the architecture of gill tissue including response of various enzymes like cholinesterase (ChE) activity, lactate dehydrogenase (LDH) activity, and lipid peroxidation (LPX) level of the freshwater fish Anabas testudineus. Activities of antioxidants like catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were also evaluated. Constant loss of gill structure and secondary lamellar fusion was observed in fishes exposed to various concentrations of naphthalene. ChE, LDH, LPx, CAT, Gpx and GSH activities indicated significant variation (p < 0.05) between the control and experimental groups. ChE activity was lowered in experimental fishes; however, LDH activity, LPx levels, and CAT activity were elevated in response to various concentrations of naphthalene as compared to control group. Both GPx and GSH activities decreased in the gill tissue of the experimental fishes. Thus, a conclusion was drawn that naphthalene is a potent toxicant capable of inflicting tissue damage leading to physiological changes in the exposed fishes.