Application of two SH-based methods for metallothionein determination in mussels and intercalibration of the spectrophotometric method: laboratory and field studies in the Mediterranean Sea

Abstract

Metallothionein (MT) induction is widely used as a biomarker of exposure to metals in mussels. The aims of the present work were first to compare the suitability of spectrophotometry and differential pulse polarography (DPP) for MT detection in mussels exposed to 200 ppb cadmium for 9 days in a laboratory experiment and in mussels sampled in different seasons from expected pollution gradients along the Mediterranean Sea; second, to intercalibrate the widely used spectrophotometric method using mussels from Saronikos Gulf. In the intercalibration of the spectrophotometric method, similar results (p>0.05) were obtained by two different research teams indicating a good reproducibility of the technique. However, polarographic and spectrophotometric methods gave significantly (p<0.05) different results in laboratory and field studies. In the laboratory experiment, MT values detected with DPP were nine times higher than with spectrophotometry. The results obtained by the two methods were significantly correlated. Both methods could discriminate between control and exposed mussels. In field studies, MT values obtained by DPP were 34-38-fold higher than with spectrophotometry, and MT concentrations measured by both methods were not correlated. This discrepancy could be due to several factors, including the low levels of bioavailable metals in the studied areas and the possibility that the different methods can measure MT isoforms differentially. Further work is needed to decipher the functions of MT isoforms in mussels. This information is relevant for the application of MT as a biomarker in biomonitoring programmes.

Metallothionein as Potential Biomarker of Cadmium Exposure in Persian Sturgeon (Acipenser persicus)

“…Considering heavy metal detoxification significance of MTs, these proteins can serve as biomarker of heavy metal pollution of the environment [12][13][14][15]. On the other hand, a comparison between the content of heavy metals and determined MTs could be very useful not only from ecotoxicological aspects but also from biochemical aspects due to the better understanding of different functions of MTs in an organism [16].…”

Temporal and spatial distribution of semicarbazide in western Laizhou Bay

“…Moreover, acetylcholinesterase (AChE) has been widely used as enzymatic biomarker of neurotoxicity for aquatic organisms after exposure to pollutants (Rickwood and Galloway, 2004). Numerous previous studies have also demonstrated metallothionein (MT) as an indicator of heavy-metal exposure (Viarengo et al, 1997;Zorita et al, 2005).…”

Review on Methods for Determination of Metallothioneins in Aquatic Organisms

“…In field studies, MT values obtained by DPP were 34-to 38-fold higher than with spectrophotometry, and the MT concentrations measured by both methods were not correlated. This discrepancy could be due to several factors, including the low levels of bioavailable metals in the studied areas and the possibility that the different methods can measure MT isoforms differentially [12]. Also, another study showed a good correlation between results obtained, for instance, using DPP and a metal saturation assay [70] and between DPP and spectrophotometric determination [73].…”