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70-kDa heat shock cognate protein expression as a putative biomarker of heavy-metal burden in Mytilus galloprovincialis.

Ratkaj I, Žurga P, Bulog A, Peter-Katalinić J, Pavelić SK - Springerplus (2015)

Bottom Line: Heavy metals naturally occur in the marine environment and ecosystems.Due to anthropogenic influence they became common waters and coastal regions pollutants in particular where their concentrations remain hazardously high.Mussels from the shipyard locality had higher heavy metal concentrations, except Fe.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia.

ABSTRACT

Background: Heavy metals naturally occur in the marine environment and ecosystems. Due to anthropogenic influence they became common waters and coastal regions pollutants in particular where their concentrations remain hazardously high. We therefore tested a protocol for combined analysis of 6 heavy metal (Pb, Cd, Cr, Zn, Fe and Hg) concentrations in mussels Mytilus galloprovincialis collected from a coastal industrial zone (shipyard locality) and mariculture facilities in combination with expression analysis of multi xenobiotic resistance related genes and stress-related gene (HSC-70).

Findings: In this paper we tested a protocol for heavy-metal levels assessment by use of a highly sensitive analytical method, ICP-OES, combined with expression analysis of multi xenobiotic resistance related genes, including the stress-related gene encoding 70-kDa heat shock cognate protein on mussels (Mytillus Galloprovincialis). Mussels from the shipyard locality had higher heavy metal concentrations, except Fe. Higher metal concentrations did not influence expression of multi xenobiotic resistance related genes with exception of stress-related gene (HSC-70) encoding 70-kDa heat shock cognate protein.

Conclusions: Our results indicate that mussels sampled in the industrial area have increased metal concentrations in comparison with the aquaculture locality, that are accompanied by increased transcript levels of HSC-70.

No MeSH data available.


Related in: MedlinePlus

Average expression of stress-related gene encoding 70-kDa heat shock protein (HSC-70) and multi xenobiotic resistance-related transporters Mvp (major vault protein), Pgp (permeability glycoprotein) and Mdr (multidrug-resistance gene) in mussels collected from polluted region in comparison with mussels from the cultivating location. Statistically significant change (fold change > 2, p < 0.05) is marked with an asterisk (*).
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Fig1: Average expression of stress-related gene encoding 70-kDa heat shock protein (HSC-70) and multi xenobiotic resistance-related transporters Mvp (major vault protein), Pgp (permeability glycoprotein) and Mdr (multidrug-resistance gene) in mussels collected from polluted region in comparison with mussels from the cultivating location. Statistically significant change (fold change > 2, p < 0.05) is marked with an asterisk (*).

Mentions: Heavy metal contamination has been recognized as one of the most persistent problem in ecosystems that ultimately influences human health due to bioaccumulation of metals in the food chain (Nandi et al. 2012). The main goal of this paper was therefore, to test a combined protocol on mussels (Mytillus Galloprovincialis) as bioindicators of heavy metal accumulation and accompanying stress for assessment of heavy-metal pollution in a polluted shipyard locality. For that purpose we used a combined protocol for analysis of stress-related gene (HSC-70), multi xenobiotic resistance (MXR)-related genes’ status and six heavy metal concentrations in mussels from a chosen location with predicted heavy-metal pollution (shipyard location) in comparison with cultivated mussels grown in an ecologically stable unpolluted environment for mariculture. Biometric analysis revealed that mussels from both locations exhibited similar condition parameters including length, width and height (Table 2). Biometric similarity points to relatively uniform general environmental conditions at both localities. Importantly, higher metal concentrations were measured in mussels collected in the industrial zone. These were four times higher for lead and zinc, three times higher levels for chromium and two times higher for mercury in comparison with levels measured in cultivated mussels (Table 3). Iron concentration was higher in cultivated mussels probably due to greater local availability in the ecosystem which is non-toxic per se (George and Coombs 1977; Szefer et al. 2004). High lead concentrations are probably due to exposure to industrial discharges or city waste-water systems in the shipyard locality. Moreover, zinc overload in mussels might be also a result of larger available zinc quantities released from sediments disturbed by boat traffic. Having in mind that increased metal concentrations were assessed in the shipyard locality, we expected to measure higher expression levels of MXR-related genes involved in the detoxification system as well (Châtel et al. 2012; Kurelec 1997). However, no significant changes in expression of MXR-related genes in mussels with higher metal levels were observed (Fig. 1). On the other hand, the stress-related gene encoding 70-kDa heat shock cognate (HSC-70) protein transcript proved to be statistically increased in mussels from the shipyard locality. Previous research (Franzellitti and Fabbri 2006) has similarly provided evidence for increased HSC-70 transcript expression after 8 h-exposure of mussels to CH3Hg2+ while exposure to Hg2+ alone induced increased HSC-70 expression only after 6 day-treatment. Similar induction of the HSC-70 gene was observed in mussels exposed to Hg2+ and Cr6+ (Franzellitti and Fabbri 2005). This might explain increased transcript levels of HSC-70 in mussels with higher total metal concentrations in the presented study as well. HSP70 is the most abundantly expressed proteins among the HSP family and has a constitutive expression in unstressed conditions (Hartl and Hayer-Hartl 2002). Changes in the mussel environment might often cause its over-expression (Franzellitti and Fabbri 2005; Piano et al. 2005). HSC-70 is however, less stress-dependent in comparison with other stress-related genes and its role might be rather specialized, i.e. in long-term cytoprotection against inorganic metal contamination (Franzellitti and Fabbri 2006; Ali et al. 1996). We believe that observed alterations in HSC-70 gene expression in mussels from the shipyard locality with higher metals level provide additional evidence on the sensitivity of Mytillus galloprovincialis to environmental changes, such as for example metal pollution as metal levels in analysed mussel specimens pointed only to moderately polluted waters. Moreover, we have shown that tested combined protocol for analysis of heavy-metal levels and activation of HSC-70 gene in edible mussels (Mytillus galloprovincialis) might be used for efficient biomonitoring, especially in mariculture facilities. Still, presented study has some limitations that prevent us from more conclusive observations. In particular, a smaller number of specimens were analysed and only two localities were chosen for comparison of evaluated parameters. The same study design should therefore, be repeated on a larger number of specimens collected from various locations and at different seasons to achieve more reliable data and comprehensive conclusions.Table 2


70-kDa heat shock cognate protein expression as a putative biomarker of heavy-metal burden in Mytilus galloprovincialis.

Ratkaj I, Žurga P, Bulog A, Peter-Katalinić J, Pavelić SK - Springerplus (2015)

Average expression of stress-related gene encoding 70-kDa heat shock protein (HSC-70) and multi xenobiotic resistance-related transporters Mvp (major vault protein), Pgp (permeability glycoprotein) and Mdr (multidrug-resistance gene) in mussels collected from polluted region in comparison with mussels from the cultivating location. Statistically significant change (fold change > 2, p < 0.05) is marked with an asterisk (*).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508280&req=5

Fig1: Average expression of stress-related gene encoding 70-kDa heat shock protein (HSC-70) and multi xenobiotic resistance-related transporters Mvp (major vault protein), Pgp (permeability glycoprotein) and Mdr (multidrug-resistance gene) in mussels collected from polluted region in comparison with mussels from the cultivating location. Statistically significant change (fold change > 2, p < 0.05) is marked with an asterisk (*).
Mentions: Heavy metal contamination has been recognized as one of the most persistent problem in ecosystems that ultimately influences human health due to bioaccumulation of metals in the food chain (Nandi et al. 2012). The main goal of this paper was therefore, to test a combined protocol on mussels (Mytillus Galloprovincialis) as bioindicators of heavy metal accumulation and accompanying stress for assessment of heavy-metal pollution in a polluted shipyard locality. For that purpose we used a combined protocol for analysis of stress-related gene (HSC-70), multi xenobiotic resistance (MXR)-related genes’ status and six heavy metal concentrations in mussels from a chosen location with predicted heavy-metal pollution (shipyard location) in comparison with cultivated mussels grown in an ecologically stable unpolluted environment for mariculture. Biometric analysis revealed that mussels from both locations exhibited similar condition parameters including length, width and height (Table 2). Biometric similarity points to relatively uniform general environmental conditions at both localities. Importantly, higher metal concentrations were measured in mussels collected in the industrial zone. These were four times higher for lead and zinc, three times higher levels for chromium and two times higher for mercury in comparison with levels measured in cultivated mussels (Table 3). Iron concentration was higher in cultivated mussels probably due to greater local availability in the ecosystem which is non-toxic per se (George and Coombs 1977; Szefer et al. 2004). High lead concentrations are probably due to exposure to industrial discharges or city waste-water systems in the shipyard locality. Moreover, zinc overload in mussels might be also a result of larger available zinc quantities released from sediments disturbed by boat traffic. Having in mind that increased metal concentrations were assessed in the shipyard locality, we expected to measure higher expression levels of MXR-related genes involved in the detoxification system as well (Châtel et al. 2012; Kurelec 1997). However, no significant changes in expression of MXR-related genes in mussels with higher metal levels were observed (Fig. 1). On the other hand, the stress-related gene encoding 70-kDa heat shock cognate (HSC-70) protein transcript proved to be statistically increased in mussels from the shipyard locality. Previous research (Franzellitti and Fabbri 2006) has similarly provided evidence for increased HSC-70 transcript expression after 8 h-exposure of mussels to CH3Hg2+ while exposure to Hg2+ alone induced increased HSC-70 expression only after 6 day-treatment. Similar induction of the HSC-70 gene was observed in mussels exposed to Hg2+ and Cr6+ (Franzellitti and Fabbri 2005). This might explain increased transcript levels of HSC-70 in mussels with higher total metal concentrations in the presented study as well. HSP70 is the most abundantly expressed proteins among the HSP family and has a constitutive expression in unstressed conditions (Hartl and Hayer-Hartl 2002). Changes in the mussel environment might often cause its over-expression (Franzellitti and Fabbri 2005; Piano et al. 2005). HSC-70 is however, less stress-dependent in comparison with other stress-related genes and its role might be rather specialized, i.e. in long-term cytoprotection against inorganic metal contamination (Franzellitti and Fabbri 2006; Ali et al. 1996). We believe that observed alterations in HSC-70 gene expression in mussels from the shipyard locality with higher metals level provide additional evidence on the sensitivity of Mytillus galloprovincialis to environmental changes, such as for example metal pollution as metal levels in analysed mussel specimens pointed only to moderately polluted waters. Moreover, we have shown that tested combined protocol for analysis of heavy-metal levels and activation of HSC-70 gene in edible mussels (Mytillus galloprovincialis) might be used for efficient biomonitoring, especially in mariculture facilities. Still, presented study has some limitations that prevent us from more conclusive observations. In particular, a smaller number of specimens were analysed and only two localities were chosen for comparison of evaluated parameters. The same study design should therefore, be repeated on a larger number of specimens collected from various locations and at different seasons to achieve more reliable data and comprehensive conclusions.Table 2

Bottom Line: Heavy metals naturally occur in the marine environment and ecosystems.Due to anthropogenic influence they became common waters and coastal regions pollutants in particular where their concentrations remain hazardously high.Mussels from the shipyard locality had higher heavy metal concentrations, except Fe.

View Article: PubMed Central - PubMed

Affiliation: Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia.

ABSTRACT

Background: Heavy metals naturally occur in the marine environment and ecosystems. Due to anthropogenic influence they became common waters and coastal regions pollutants in particular where their concentrations remain hazardously high. We therefore tested a protocol for combined analysis of 6 heavy metal (Pb, Cd, Cr, Zn, Fe and Hg) concentrations in mussels Mytilus galloprovincialis collected from a coastal industrial zone (shipyard locality) and mariculture facilities in combination with expression analysis of multi xenobiotic resistance related genes and stress-related gene (HSC-70).

Findings: In this paper we tested a protocol for heavy-metal levels assessment by use of a highly sensitive analytical method, ICP-OES, combined with expression analysis of multi xenobiotic resistance related genes, including the stress-related gene encoding 70-kDa heat shock cognate protein on mussels (Mytillus Galloprovincialis). Mussels from the shipyard locality had higher heavy metal concentrations, except Fe. Higher metal concentrations did not influence expression of multi xenobiotic resistance related genes with exception of stress-related gene (HSC-70) encoding 70-kDa heat shock cognate protein.

Conclusions: Our results indicate that mussels sampled in the industrial area have increased metal concentrations in comparison with the aquaculture locality, that are accompanied by increased transcript levels of HSC-70.

No MeSH data available.


Related in: MedlinePlus