Marine Microbial Response to Heavy Metals: Mechanism, Implications and Future Prospect.

Growing levels of pollution in marine environment has been a matter of serious concern in recent years. Increased levels of heavy metals due to improper waste disposal has led to serious repercussions. This has increased occurrences of heavy metals in marine fauna. Marine microbes are large influencers of nutrient cycling and productivity in oceans. Marine bacteria show altered metabolism as a strategy against metal induced stress. Understanding these strategies used to avoid toxic effects of heavy metals can help in devising novel biotechnological applications for ocean clean-up. Using biological tools for remediation has advantages as it does not involve harmful chemicals and it shows greater flexibility to environmental fluctuations. This review provides a comprehensive insight on marine microbial response to heavy metals and sheds light on existing knowledge about and paves for new avenues in research for bioremediation strategies.

Correlation of melanophore index with a battery of functional genomic stress indicators for measurement of environmental stress in aquatic ecosystem.

The correlation of primary stress indicator; melanophore index (MI) with set of genomic stress indicators is important for a better understanding of the cellular stress pathway induced by xenobiotics in aquatic species. This study presents a correlation between melanophore index (MI) and genomic stress indicators in Oreochromis mossambicus treated with lead nitrate, phenol and hexachlorocyclohexane (HCH). O. mossambicus was exposed to sub-lethal concentrations of the different LC50 values (96 h) of the tested chemicals at varying exposure periods and the response via genomic stress indicators and scale melanophores were assessed in accordance with standard protocols. Melanophore index decreased significantly (p<0.01) in a time dependent pattern to the tested chemicals. Gene expression showed significant time dependent increase in the expression of heat shock proteins (HSP70 and HSP60). Vitellogenin (Vtg) expression insignificantly altered. Significant increase in the expression of melanin concentrating hormone (MCH) was observed in response to hexachlorocyclohexane (HCH) in the treated fish. The findings demonstrated an inverse relationship between melanophore index and the set of genomic stress indicators.

Effect of idol immersion on water quality and Tilapia fish in Futala, Gandhisagar and Ambazari lakes of Nagpur, India.

INTRODUCTION: Idol immersion activity is one of the sources of heavy metal pollution in the lakes of India. Futala, Gandhisagar and Ambazari lakes of Nagpur city are highly involved with idol immersion activity. CASE DESCRIPTION: In this study, water and Tilapia fish (Oreochromis mossambicus) of Futala, Gandhisagar and Ambazari lakes were analyzed for heavy metals by using inductively coupled plasma optical emission spectrometry (ICP-OES). DISCUSSION AND EVALUATION: The results were high compared with the Bureau of Indian Standards (BIS) for water quality and Food and Agriculture Organization (FAO)/World Health Organization (WHO) for fish. The results showed appreciable high levels of heavy metal as lead, cadmium, copper, iron and manganese in water and fish in study lakes. It was observed that Gandhi Sagar lake was more contaminated after the idol immersion activity. Concentrations of Pb and Cd in fish of Gandhisagar lake were found high levels, ranged 0.83 and 0.47 µg/g respectively. CONCLUSION: The results of the present investigation indicate the unsafe condition for human consumption and environmental health.