Levels of Toxicity Screening of Environmental Chemicals Using Aquatic Invertebrates - A Review

Effective screening of the toxicity of chemicals using living organisms has been considered as a major issue of environmental biomonitoring. The principle of toxicity screening involves the quantitation of toxin-induced shift of biological response or tissue morphology of test species both in vivo and in vitro. Most of the toxin appears to function as biological response modifiers at a defined concentration and span of exposure. In recent years, invertebrates have been gaining a special scientific attention for being utilized as suitable model for toxicity screening. Invertebrates like crab, mollusks, sponge, and earthworm have already been established as model organisms for toxicity screening and analyses. A number of environmental toxins like arsenic, pyrethroid, pesticides, heavy metals, and washing soda can be screened for their toxicities using invertebrate species. Cellular and subcellular parameters like blood cell density, lysosomal membrane stability, cellular damage, apoptosis, micronucleation, and cytotoxic response of invertebrates had been established as biomarkers of environmental toxicity. Toxin-induced histopathological and behavioral shift had been suggested as effective parameters of toxicity screening in model invertebrates. However, reactivity and responses of invertebrates toward xenobiotics are often recorded to be species specific and related to the chemistry of the toxin. Current article reviews different levels of toxicity screening using invertebrate as test model

Behavioural shift of estuarine mudcrab as biomarker of arsenic exposure in Sundarbans estuary of West Bengal

Mudcrab Scylla serrata (Crustacea: Decapoda) in an ecologically and economically important species of Sundarbans Biosphere Reserve was studied for its behaviour under the exposure of toxic arsenic - a common xenobiotic of this area. The behavioural profile of aquatic animals exposed to diverse toxicants are considered as an index to estimate the degree and nature of stress experienced by the animals both in nature and in experimental conditions. Present investigation involved study of selected behavioural shift of S. serrata under the sublethalconcentrations of 1, 2 and 3 ppm of sodium arsenite for 1, 2, 3 and 4 days in controlled laboratory condition. Exposure to arsenic resulted an appearance of selected abnormal behavioural manifestation including tendency of avoidance, hypersecretion of mucoid element and release of excess excretory products. Toxin induced alteration of studied behaviour is indicative to possible shift in the overall physiological functions and biological activities of this important species in its natural habitat. Chronic exposure to 3 ppm of sodium arsenite for 30 days may lead to decline this economically important species in Sundarbans Biosphere Reserve

Immunotoxicological Threats of Pollutants in Aquatic Invertebrates

Immunology deals with the physiological activity of organisms to defend against pathogen and toxin invasion. Invertebrates residing in aquatic ecosystems often face toxicological threat arises from habitat pollution. The aquatic habitat of invertebrates is in the precarious risk of pollution caused by diverse groups of environmental toxins. Immunotoxins have been considered as a special group of pollutants capable of affecting the immunological profile of organisms. Invertebrates residing in water bear ecological, economical, medicinal, industrial, nutritional and biotechnological significance. Global aquatic bioresource is largely composed of invertebrates belonging to multiple Phyla. These organisms, including insects, snails, clams, mussels, crabs and sponges, are physiologically dependent on innate immunological response for defense against pathogen and environmental contaminants. External physicochemical barriers of invertebrates act as primary line of defen against toxin entry. Principal barriers have been identified as shell, tunic, test, carapace, mucus, etc., in diverse species. Toxin-induced morphological damage of specialized immunocytes of invertebrates has been reported. Toxin-induced shift in density, surface adhesion efficacy and aggregation of blood cells or haemocytes have been identified as major xenobiotic stress in invertebrates. Various environmental toxins are capable of initiating alteration in the innate phagocytic response and cytotoxicity of blood cells. Lysosomes of invertebrate haemocytes are functionally involved in intracellular destruction of environmental pathogens. Toxins like arsenic, pyrethroid pesticides, azadirachtin and washing soda were reported to increase the relative fragility of lysosomal membranes of immunocytes. This often leads to impairment in the efficacy of invertebrates to destroy pathogen under the exposure of pollutants. Xenobiotics like pyrethroid pesticides have been recorded to affect apoptosis and necrosis of invertebrate immunocytes. Selected toxin-induced morphological damages of heart, gill, digestive gland, mantle and antennae may result in the overall impairment in homeostatic levels of invertebrates inhabiting the polluted environment. Global environment, in recent times, is under the serious threat of contamination by diverse chemical compounds of unknown or less known toxicity. A thorough ecotoxicological analysis at cellular and molecular levels needs to be carried out in invertebrates occupying the different realms of the planet in future

Computer Assisted Drug Design of Tinosporide for treatment of Cancer: a Combined Density Functional and Molecular Docking Study

This article discusses theory behind the most important methods and recent successful applications of halogen‑directed tinosporide, ligand-based methods use only ligand information for predicting activity depending on its similarity/dissimilarity to previously known active ligands. We review widely used ligand-based methods such as ligand-based pharmacophores, molecular descriptors, and quantitative structure-activity relationships. In addition, important tools such as target/ligand data bases, homology modeling, ligand ADMET etc., and necessary for successful implementation of various computer-aided drug discovery/design methods in best analogue of tinosporides discovery are discussed. Finally, computational methods for toxicity prediction and optimization for favorable physiologic properties are discussed with successful lead for tinosporides from literature. The therapeutic potential of tinosporide has been studied extensively and the active compounds of tinosporide are shown to be involved in modulating multiple physiological responses. Moreover this article will review the structure of series of halogen-directed tinosporides before illustration on how the molecules exert their functions via interactions with various signal transducer and activator proteins of transcription which were designed by homology modeling. Strategies for CADD vary depending on the extent of structural and other information available regarding the target (enzyme/receptor) and the ligands. The process by which a new tinosporide product is brought to market stage is referred to by a number of names most commonly as the development chain and consists of a number of distinct stages. Keywords: CADD; ADMET; Molecular Modeling; Tinosporide

Effect of integrated nutrient management on the nutrient accumulation and status of post-harvest soil of brinjal (Solanum melongena L.) under Nadia conditions (West Bengal), India

A field experiment was carried out at the Central Research Farm, Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India to study the effects of integrated nutrient management on the nutrient accumulation (dry weight recoveries) in brinjal and plant nutrient status of the post- harvest soil of brinjal under Nadia conditions. The results revealed that the treatment consisting of 75% RDF (RDF i.e. N:P:K:: 125:100:50) + Azospirillum + phosphate solubilising bacteria (PSB) + Borax @ 10 kg ha-1 recorded the highest oxidizable organic carbon (8.049 g kg-1), total nitrogen (1.05 g kg-1) , available nitrogen (212.67g kg-1), available phosphorus (76.20g kg-1) and available potassium (177.59 g kg-1) in the post harvest soils of brinjal. On the other hand, 75% RDF + Azospirillum + PSB + FeSO4 @ 50 kg ha-1 recorded the highest available iron (26.14 kg ha-1) and the treatment consisting of 75% RDF + Azospirillum + PSB + ZnSOâ‚„ @ 25 kg ha-1 recorded the highest soil available zinc (7.62 kg ha-1) while 75% RDF + Azo + PSB + Borax @ 10 kg ha-1 recorded the highest available Boron content (0.78 kg ha-1) of the post harvest soil of Brinjal. Highest brinjal yield (14.96 t ha-1) was supported by the treatment consisting of 75% RDF + Azospirillum + PSB + Boron @ 10 Kg ha-1. Meager information was available regarding the performance of integrated application of organics and micronutrient on brinjal in the experimental location. The present study may enlighten this unexplored section of nutrient management in brinjal

Immunogenic Modulations Induced by Prospective Anti-Malarial Herbal Extracts in Murine Model

Keeping in view the ever increasing problem of drug resistance and affordability of the antimalarial drugs by the poor mass, herbal medicines can become an important and alternative sustainable strategy for malaria treatment. Aqueous extracts of three Himalayan herbs― _Equisetum ravense_, _Artemisia vulgaris_ and _Centella asiatica_, with reported antimalarial property were screened for clinical efficacy against a local strain of _Plasmodium vivax_ antigen in murine model. _E. arvense_ extract was consistent in boosting phagocytic activity, nitric oxide generation, acid phosphatase and alkaline phosphatase activities in the peritoneal macrophages. The effectiveness of the rest herbals was discrete. A need for further detailed investigation to evaluate the clinical efficacy of these herbals seems essential

Effect of Cold Stress on Pyridostigmine Pretreated Rats Exposed to an Organophosphorous Compound

Context: Pyridostigmine bromide (PB) is a quaternary ammonium compound and has been approved as a pretreatment drug against toxic organophosphorous (OP) compounds. The stressful demands of modern military activity include a broad range of activities at extreme cold temperatures along with various physical activities. Objective: The effect of “sign free” dose of PB (0.075 mg/kg body weight) against a toxic OP compound diisopropyl fluorophosphate (DFP) was reassessed in rats. Electrocardiographic (ECG) studies in hypothermic and pretreatment conditions were undertaken to assess the cardioprotective role of PB. Total Antioxidant Status (TAS) was quantified to assess the degree of oxidative stress imposed under such conditions. Possible protective role of pyridostigmine in rat lymphocytes was also determined.Materials& Methods: TAS was estimated spectrophotometrically and the expression of interferon-γ (IFNγ) was measured by Fluorescence Activated Cell Sorting. ECG was monitored by standard protocol.Results: ECG recording showed that the PR and QT interval progressively increased along with widening of QRS complex. There was a progressive fall in heart rate as the body temperature decreased. TAS significantly decreased (p≤0.001) in hypothermic conditions and when pretreated with sign free dose of PB before cold induction (p≤0.001). Following immunostaining of lymphocytes by FITC conjugated mouse anti-rat IFNγ monoclonal antibody, 9.1% of lipopolysaccharide elicited parent cells showed positive IFNγ expression. Hypothermic stress inhibited IFNγ expression (3.6% of parent cells) which was recovered to 6.8% upon pre-treatment with sign-free dose of pyridostigmine. Conclusion: This study is indicative of a possible protective role of PB against hypothermic stress

Cell Signalling - Thermodynamics and Molecular Control

Intracellular signal transduction is an important topic of research in cell and molecular biology. It has a wide range of implications in growth, differentiation, development, animal polarity, cellular response monitoring, and many disease processes, including cancer. The functional homeostasis of a cell is assumed to be maintained by an intricate network of signaling that evolved through natural selection. This book includes chapters written in the frontier areas of research on cell signaling. Issues such as information thermodynamics, master regulation of immune tolerance, genetically encoded reporter circuits and their applications, hypoxia, and vitamin K2 mediated signaling processes are addressed and discussed by eminent researchers of the field

Earthworms - The Ecological Engineers of Soil

This book in two sections represents the current trend of research in ecology and biology of earthworms. In section ""Ecology and Diversity"" the authors reported the ecological and geographical uniqueness and diversity of earthworms in different environmental terrains of Siberia and Mexico. Functional interaction between earthworms and soil nematodes was elucidated with reference to vermicomposting and agricultural systems. Importance of digital library was highlighted for inventorization and taxonomical identification of earthworms. In section ""Vermicomposting"" the importance of maintaining pure cultures was discussed from the viewpoint of growth rate and the reproduction of composting species. This section includes article describing the management-related issues like roles of physicochemical parameters of soil and feed mixture on growth and reproduction of commercially important species of earthworm