Toxicity Evaluation of Six Textile Dyes on Growth, Metabolism and Elemental Composition (C, H, N, S) of Microalgae Spirulina platensis: The Environmental Consequences.

A concentration-dependent decrease in growth rate and pigment concentration of the blue-green alga Spirulina platensis was recorded after the exposure to graded (5-40 ppm) concentration of six textile dyes. The profile of vital elements (C, H, N, S) also showed a significant variation due to dye toxicity. The algal population showed up to 50% decrease in protein content after exposure to the dyes. Among the pigments, the dye exposure resulted in > 90% decreases in phycocyanin however, total chlorophyll and carotenoids exhibited up to a 50% decrease compared to control. The findings indicate that the unregulated discharge of textile dyes will directly impact the photoautotrophic organisms leading to ecological imbalance in aquatic ecosystems. Overall observations of the report provide baseline information about the toxicity of textile dyes and giving a better insight into the little-understood mechanisms of dye toxicity.

Toxic Effects of Selected Textile Dyes on Elemental Composition, Photosynthetic Pigments, Protein Content and Growth of a Freshwater Chlorophycean Alga Chlorella vulgaris.

Toxicity of three textile dyes-Optilan yellow, Drimarene blue and Lanasyn brown, was evaluated in a green alga Chlorella vulgaris. The unialgal populations of the alga showed a concentration-dependent decrease in specific growth rate and pigments after exposure to graded concentrations of above dyes. The elemental profile (C, H, N, S) of the treated and untreated cells showed a change which was evident from a significant decrease in the quantity of elements after exposure to the dyes. The observations provide convincing evidence that the textile dyes inhibited the growth, pigment and elemental composition of the algal cells. The findings of the present investigation will contribute to gaining a better understanding of the impacts of textile dyes on ecologically important aquatic organisms.

Molecular characterization of inhibin-A: Structure and expression analysis in Clarias batrachus.

The inhibins are disulphide-linked heterodimeric glycoproteins that belong to the TGFß superfamily. Inhibins have been well studied in mammals but the information about their structure and function is very limited in lower vertebrates. The aim of the present study was to characterize inhibin-A and to understand its receptor binding interaction, and to evaluate its biological function in Clarias batrachus. Structure prediction of inhibin-A revealed two glycosylation sites on inhibin-α (Asp262 and Asn334). Docking of inhibin-A with its receptor; betaglycan and Act RIIA showed that residues Ser321, Gly324 and Leu325 of inhibin-α are involved in high affinity binding with betaglycan while inhibin-ßA bound to Act RIIA by forming hydrogen bonds. The mRNA transcript analysis of various tissues indicated the presence of higher to moderate expression of inhibin-α and inhibin-ßA in the gonads and the extra-gonadal tissues. Further, stage specific expression showed decreased levels of inhibin-α in the gonads during the annual reproductive cycles. Inhibin-ßA, activin-ßB and Act RIIA increased in the brain during spawning while FSHr increased in the gonads during the preparatory phase. Our study provides molecular, structural and functional insights of inhibin-A for the first time in C. batrachus.

Biomarkers for assessing chronic toxicity of carbamazepine, an anticonvulsants drug on Pangasianodon hypophthalmus (Sauvage, 1878).

In recent times, carbamazepine (CBZ) as an anticonvulsants drug has raised attention because of its safety concern in the aquatic environment. The present study aimed to evaluate the sub-lethal effects of CBZ (1%, 0.1 % and 0.01 % of 96 h LC50) on P. hypophthalmus for 60 days based on haematological, biochemical, and genotoxicity biomarkers. Chronic exposure of CBZ altered blood profiles (total erythrocyte count, packed cell volume, haemoglobin) and serum biomarkers such as alkaline phosphates, cholesterol, lactate dehydrogenase and transaminase enzymes. Oxidative stress biomarkers such as superoxide dismutase (SOD) and catalase (CAT) activity were also substantially affected in all treatments. Genotoxicity study revealed the formation of micronucleus in erythrocytes of exposed fish. Integrated Biomarker Response (IBR) study showed cholesterol, serum glutamic oxaloacetic transaminase (SGOT) in serum and SOD, CAT in liver tissue are the best organ-based enzyme biomarkers. The present report concludes that an environmentally realistic concentration of CBZ can pose a serious threat to aquatic organisms.

Inhibin anti-peptide antibody macromolecule: An approach to improve fecundity in Clarias batrachus.

Inhibins are members of the transforming growth factor beta (TGFß) superfamily known to regulate ovarian functions through stimulation of the hypothalamo-pituitary-gonadal axis. In the present study, we aimed to design a species-specific inhibin-α chimeric peptide (ICP) and evaluate the effect of immunoneutralization using anti-ICP antisera to enhance the reproductive performance in female Clarias batrachus. Injection of anti-ICP antisera caused a significant increase in the number of oocytes at a medium dose (200 µl) in comparison to high dose (400 µl) and control (normal rabbit serum). Histological observations confirmed the dose-dependent advancement in oocyte maturation. Furthermore, anti-ICP antisera treated groups exhibited a significant increase in the serum concentrations of follicle stimulating hormone (FSH) and 17ß-estradiol (E2) hormones. The anti-ICP antisera decreased the mRNA expression levels of inhibin-α while stimulated the transcript levels of inhibin-ßA, FSHß, CYP 19a1, 3ß-HSD and StAR respectively in a dose-dependent manner. Collectively, these findings indicate that anti-ICP antibody macromolecules modulate the endogenous reproductive hormonal secretion and enhance oocyte quality and quantity in female C. batrachus. This is the first report wherein antibodies against inhibins were used to promote reproductive performances and investigate the underlying molecular mechanisms in fishes.

Multi-response optimization of Artemia hatching process using split-split-plot design based response surface methodology.

A novel method, BBD-SSPD is proposed by the combination of Box-Behnken Design (BBD) and Split-Split Plot Design (SSPD) which would ensure minimum number of experimental runs, leading to economical utilization in multi- factorial experiments. The brine shrimp Artemia was tested to study the combined effects of photoperiod, temperature and salinity, each with three levels, on the hatching percentage and hatching time of their cysts. The BBD was employed to select 13 treatment combinations out of the 27 possible combinations that were grouped in an SSPD arrangement. Multiple responses were optimized simultaneously using Derringer's desirability function. Photoperiod and temperature as well as temperature-salinity interaction were found to significantly affect the hatching percentage of Artemia, while the hatching time was significantly influenced by photoperiod and temperature, and their interaction. The optimum conditions were 23 h photoperiod, 29 °C temperature and 28 ppt salinity resulting in 96.8% hatching in 18.94 h. In order to verify the results obtained from BBD-SSPD experiment, the experiment was repeated preserving the same set up. Results of verification experiment were found to be similar to experiment originally conducted. It is expected that this method would be suitable to optimize the hatching process of animal eggs.