Immunotoxicity of washing soda in a freshwater sponge of India

Stem cells of aquatic invertebrates as an advanced tool for assessing ecotoxicological impacts

Environmental stressors are assessed through methods that quantify their impacts on a wide range of metrics including species density, growth rates, reproduction, behaviour and physiology, as on host-pathogen interactions and immunocompetence. Environmental stress may induce additional sublethal effects, like mutations and epigenetic signatures affecting offspring via germline mediated transgenerational inheritance, shaping phenotypic plasticity, increasing disease susceptibility, tissue pathologies, changes in social behaviour and biological invasions. The growing diversity of pollutants released into aquatic environments requires the development of a reliable, standardised and 3R (replacement, reduction and refinement of animals in research) compliant in vitro toolbox. The tools have to be in line with REACH regulation 1907/2006/EC, aiming to improve strategies for potential ecotoxicological risks assessment and monitoring of chemicals threatening human health and aquatic environments. Aquatic invertebrates' adult stem cells (ASCs) are numerous and can be pluripotent, as illustrated by high regeneration ability documented in many of these taxa. This is of further importance as in many aquatic invertebrate taxa, ASCs are able to differentiate into germ cells. Here we propose that ASCs from key aquatic invertebrates may be harnessed for applicable and standardised new tests in ecotoxicology. As part of this approach, a battery of modern techniques and endpoints are proposed to be tested for their ability to correctly identify environmental stresses posed by emerging contaminants in aquatic environments. Consequently, we briefly describe the current status of the available toxicity testing and biota-based monitoring strategies in aquatic environmental ecotoxicology and highlight some of the associated open issues such as replicability, consistency and reliability in the outcomes, for understanding and assessing the impacts of various chemicals on organisms and on the entire aquatic environment. Following this, we describe the benefits of aquatic invertebrate ASC-based tools for better addressing ecotoxicological questions, along with the current obstacles and possible overhaul approaches.

Effects of copper oxide nanoparticle on gill filtration rate, respiration rate, hemocyte associated immune parameters and oxidative status of an Indian freshwater mussel

Waterbodies of India support a wide range of molluscs including Lamellidens marginalis, a pearl forming edible mussel of ecological significance. Report of copper oxide nanoparticle toxicity in Indian molluscs is limited in scientific literature. L. marginalis is a gill respiring filter feeder, which is toxicologically vulnerable to exposure of copper oxide nanoparticles liberated from electrical, textile and polymer industries. Experimental exposure of copper oxide nanoparticles for 7 days yielded a decrease in gill filtration rate, respiration rate, total count and phagocytic response of hemocytes, the chief immunoeffector cells of L. marginalis. Nanoparticle exposure resulted in decrease of phagocytic response of mussel hemocytes. Decrease in nitric oxide generation and phenoloxidase activity were recorded in L. marginalis exposed to 0.5, 1 and 5 mg copper oxide nanoparticles per litre of water for 7 and 14 days. Superoxide anion generation in hemocytes was increased under the exposure of copper oxide nanoparticles. Increase in superoxide anion and decrease in the activities of superoxide dismutase and catalase were indicative to oxidative stress in mussels. Copper oxide nanoparticle induced shift in filtration and respiration rate along with the hemocyte associated immune parameters were suggestive to an acute immunophysiological stress in L. marginalis. We estimated the functional performance of gill and physiological status of aquatic respiration in L. marginalis exposed to copper oxide nanoparticles. A parallel set of estimation of each parameter was carried out in L. marginalis exposed to identical copper sulphate concentrations to record and compare the ionic toxicity of copper in the same specimen.

Washing soda induced alteration of the differential cell count, nonself surface adhesion efficacy and nuclear morphology of the polyphenotypic cells of a freshwater sponge of India

Washing soda has been identified as a precarious contaminant of the freshwater ponds and lakes, the natural habitat of Eunapius carteri. Treatment of sublethal concentrations of washing soda for 384 hours exhibited a significant decrease in the densities of blast like cells, small and large amoebocytes. The percentage occurrence of granular cells and archaeocytes yielded a marked increase against the experimental concentrations of washing soda. Washing soda mediated alterations in the differential cell densities of E. carteri indicative of a state of physiological stress and an undesirable shift in the cellular homeostasis of the organism distributed in polluted environment. Experimental exposure of washing soda yielded a significant increase in the cellular dimensions of large amoebocytes and archaeocytes. Prolonged treatment with washing soda presented a gross reduction in nonself surface adhesion efficacy of E. carteri cells. Experimental concentrations of washing soda resulted in a dose dependent increment in the frequencies of binucleation and micronucleation in the cells of E. carteri. The data were indicative of a high level of genotoxicity of washing soda in E. carteri. The present investigation provides an important information base in understanding the toxin induced chemical stress on the archaic immune defense of a primitive urmetazoa.

Shift in aggregation, ROS generation, antioxidative defense, lysozyme and acetylcholinesterase activities in the cells of an Indian freshwater sponge exposed to washing soda (sodium carbonate)

Washing soda, chemically identified as anhydrous sodium carbonate, is a popular cleaning agent among the rural and urban populations of India which often contaminates the freshwater ponds and lakes, the natural habitat of sponge Eunapius carteri. Present investigation deals with estimation of cellular aggregation, generation of ROS and activities of antioxidant enzymes, lysozyme and acetylcholinesterase in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Prolonged treatment of washing soda inhibited the degree of cellular aggregation. Experimental exposure of 8 and 16mg/l of sodium carbonate for 48h elevated the physiological level of reactive oxygen species (ROS) generation in the agranulocytes, semigranulocytes and granulocytes of E. carteri, whereas, treatment of 192h inhibited the ROS generation in three cellular morphotypes. Activities of superoxide dismutase, catalase and glutathione-S-transferase were recorded to be inhibited under prolonged exposure of washing soda. Washing soda mediated inhibition of ROS generation and depletion in the activities of antioxidant enzymes were indicative to an undesirable shift in cytotoxic status and antioxidative defense in E. carteri. Inhibition in the activity of lysozyme under the treatment of sodium carbonate was suggestive to a severe impairment of the innate immunological efficiency of E. carteri distributed in the washing soda contaminated habitat. Washing soda mediated inhibition in the activity of acetylcholinesterase indicated its neurotoxicity in E. carteri. Washing soda, a reported environmental contaminant, affected adversely the immunophysiological status of E. carteri with reference to cellular aggregation, oxidative stress, antioxidative defense, lysozyme and acetylcholinesterase activity.

Morphological alteration, lysosomal membrane fragility and apoptosis of the cells of Indian freshwater sponge exposed to washing soda (sodium carbonate)

Washing soda is chemically known as sodium carbonate and is a component of laundry detergent. Domestic effluent, drain water and various anthropogenic activities have been identified as major routes of sodium carbonate contamination of the freshwater ecosystem. The freshwater sponge, Eunapius carteri, bears ecological and evolutionary significance and is considered as a bioresource in aquatic ecosystems. The present study involves estimation of morphological damage, lysosomal membrane integrity, activity of phosphatases and apoptosis in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Exposure to washing soda resulted in severe morphological alterations and damages in cells of E. carteri. Fragility and destabilization of lysosomal membranes of E. carteri under the sublethal exposure was indicative to toxin induced physiological stress in sponge. Prolonged exposure to sodium carbonate resulted a reduction in the activity of acid and alkaline phosphatases in the cells of E. carteri. Experimental concentration of 8 mg/l of washing soda for 192 h yielded an increase in the physiological level of cellular apoptosis among the semigranulocytes and granulocytes of E. carteri, which was suggestive to possible shift in apoptosis mediated immunoprotection. The results were indicative of an undesirable shift in the immune status of sponge. Contamination of the freshwater aquifers by washing soda thus poses an alarming ecotoxicological threat to sponges.