Arylamine N-acetyl Transferase (NAT) in the blue secretion of Telescopium telescopium: xenobiotic metabolizing enzyme as a biomarker for detection of environmental pollution.

Bapi Gorain,Sanmoy Karmakar,Tuhinadri Sen,Samir Kumar Samanta,Murari Mohan Pal,Ratul Sarkar,Sumon Chakraborty

doi:10.1186/2193-1801-3-666

Abstract

Telescopium telescopium, a marine mollusc collected from Sundarban mangrove, belongs to the largest mollusca phylum in the world and exudes a blue secretion when stimulated mechanically. The blue secretion was found to metabolize (preferentially) para-amino benzoic acid, a substrate for N-acetyl transferase (NAT), thereby indicating acetyl transferase like activity of the secretion. Attempts were also made to characterise bioactive fraction of the blue secretion and to further use this as a biomarker for monitoring of marine pollution. NAT like enzyme from marine mollusc is a potential candidate for detoxification of different harmful chemicals. A partially purified extract of blue secretion was obtained by fractional precipitation with (NH4)2SO4. From different fractions obtained by precipitation, the 0–30% fraction (30S) displayed NAT like activity (using para amino benzoic acid as a substrate with para nitrophenyl phosphate or acetyl coenzyme A as acetyl group donors). Maximum NAT like enzyme activity was attained at 25°C and at a pH of 6. The enzyme activity was found to be inhibited by 5 mM phenyl methyl sulfonyl fluoride. The divalent metal ions reduced NAT like activity of 30S. Moreover, Cu2+ and Zn2+ (at concentration of 1 mM) completely inhibited NAT activity. The thermal stability and bench-top stability studies were performed and it was found that the enzyme was stable at room temperature for more than 24 hours. Results from the present study further indicate that heavy metal content in blue secretion gradually decreased from pre-monsoon to post-monsoon season, which also corresponded to the change in NAT like activity. Therefore, this article stresses the importance of biomarker research for monitoring pollution.

Highlights

Telescopium telescopium (Linnaeus, 1758), a mangrove gastropod mollusc, is the most dominant molluscan species of Sundarban mangrove (Figure 1)
The present study was an attempt to detect the presence of a biomarker from blue secretion of Telescopium telescopium
The present study focuses on possible correlation of biomarker with different heavy metals

Summary

Introduction

Telescopium telescopium (Linnaeus, 1758) (mud whelk or mangrove snail), a mangrove gastropod mollusc, is the most dominant molluscan species of Sundarban mangrove (Figure 1). In terms of total number of species, mollusca are numerically second largest phyla after arthropoda, among the invertebrates found in Sundarban ecosystem. This species is widely consumed as food in other parts of the world (Swadling 1977), such practice is uncommon in Sundarbans. The mollusc is found abundantly in the coastline of India and resides mainly in the estuarine environment in the basin of different rivers. It is well known that this particular mollusc species secretes a blue coloured viscous liquid when disturbed by any external mechanical stimuli. The capability of surviving in the intertidal zone may make them an attractive subject for exploring the impact of environmental pollutants

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