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Glutathione Transferases Responses Induced by Microcystin-LR in the Gills and Hepatopancreas of the Clam Venerupis philippinarum.

Carneiro M, Reis B, Azevedo J, Campos A, Osório H, Vasconcelos V, Martins JC - Toxins (Basel) (2015)

Bottom Line: No significant changes were found in PPP2 activity, the main target of MCs, for both organs.Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs.Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

View Article: PubMed Central - PubMed

Affiliation: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, Porto 4050-123, Portugal. marianarcarneiro@gmail.com.

ABSTRACT
A multi-method approach was employed to compare the responses of Glutatione Transferases (GSTs) in the gills and hepatopancreas of Venerupis philippinarum to microcystins (MCs) toxicity. In this way, using the cytosolic fraction, the enzymatic activity of GSTs, superoxide dismutase (SOD), serine/threonine protein phosphatases (PPP2) along with the gene expression levels of four GST isoforms (pi, mu, sigma1, sigma2) were investigated in both organs of the clams exposed for 24 h to 10, 50 and 100 μg L(-1) of MC-LR. Cytosolic GSTs (cGSTs) from both organs of the high dose exposed clams were purified by glutathione-agarose affinity chromatography, characterized kinetically and the changes in the expression of cGSTs of the gills identified using a proteomic approach. MC-LR caused an increase in GST enzyme activity, involved in conjugation reactions, in both gills and hepatopancreas (100 μg L(-1) exposure). SOD activity, an indicator of oxidative stress, showed significantly elevated levels in the hepatopancreas only (50 and 100 μg L(-1) exposure). No significant changes were found in PPP2 activity, the main target of MCs, for both organs. Transcription responses revealed an up-regulation of sigma2 in the hepatopancreas at the high dose, but no significant changes were detected in the gills. Kinetic analysis evidenced differences between gills of exposed and non-exposed extracts. Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs. Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

No MeSH data available.


Related in: MedlinePlus

Glutatione transferases (GST) activity expressed as μmol of 1-chloro-2,4-dinitrobenzene glutathione (CDNB-GSH) conjugate per min per mg of protein in the gills and hepatopancreas of V. philippinarum exposed to three different concentrations of purified microcystin-LR (MC-LR). Data are expressed as mean ± SD (n = 3). Capital letters are depicted for the gills and lowercase letters for the hepatopancreas. Treatments that do not share a letter are significantly different (p < 0.05).
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toxins-07-02096-f001: Glutatione transferases (GST) activity expressed as μmol of 1-chloro-2,4-dinitrobenzene glutathione (CDNB-GSH) conjugate per min per mg of protein in the gills and hepatopancreas of V. philippinarum exposed to three different concentrations of purified microcystin-LR (MC-LR). Data are expressed as mean ± SD (n = 3). Capital letters are depicted for the gills and lowercase letters for the hepatopancreas. Treatments that do not share a letter are significantly different (p < 0.05).

Mentions: The wide-ranging substrate used, 1-chloro-2,4-dinitrobenzene (CDNB), catalyzes most of the known GST isoforms [41]. In our work, GST activity levels were consistently lower in the hepatopancreas than in the gills (more than three-fold). GST activity from both organs showed an increase trend with increasing MC-LR levels (Figure 1). However, a significant (p < 0.05) increase (1.5-fold for both organs) in relation to control was detected for the high dose exposed group (100 μg L−1) in the gills and hepatopancreas.


Glutathione Transferases Responses Induced by Microcystin-LR in the Gills and Hepatopancreas of the Clam Venerupis philippinarum.

Carneiro M, Reis B, Azevedo J, Campos A, Osório H, Vasconcelos V, Martins JC - Toxins (Basel) (2015)

Glutatione transferases (GST) activity expressed as μmol of 1-chloro-2,4-dinitrobenzene glutathione (CDNB-GSH) conjugate per min per mg of protein in the gills and hepatopancreas of V. philippinarum exposed to three different concentrations of purified microcystin-LR (MC-LR). Data are expressed as mean ± SD (n = 3). Capital letters are depicted for the gills and lowercase letters for the hepatopancreas. Treatments that do not share a letter are significantly different (p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488691&req=5

toxins-07-02096-f001: Glutatione transferases (GST) activity expressed as μmol of 1-chloro-2,4-dinitrobenzene glutathione (CDNB-GSH) conjugate per min per mg of protein in the gills and hepatopancreas of V. philippinarum exposed to three different concentrations of purified microcystin-LR (MC-LR). Data are expressed as mean ± SD (n = 3). Capital letters are depicted for the gills and lowercase letters for the hepatopancreas. Treatments that do not share a letter are significantly different (p < 0.05).
Mentions: The wide-ranging substrate used, 1-chloro-2,4-dinitrobenzene (CDNB), catalyzes most of the known GST isoforms [41]. In our work, GST activity levels were consistently lower in the hepatopancreas than in the gills (more than three-fold). GST activity from both organs showed an increase trend with increasing MC-LR levels (Figure 1). However, a significant (p < 0.05) increase (1.5-fold for both organs) in relation to control was detected for the high dose exposed group (100 μg L−1) in the gills and hepatopancreas.

Bottom Line: No significant changes were found in PPP2 activity, the main target of MCs, for both organs.Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs.Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

View Article: PubMed Central - PubMed

Affiliation: CIIMAR/CIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Rua dos Bragas 289, Porto 4050-123, Portugal. marianarcarneiro@gmail.com.

ABSTRACT
A multi-method approach was employed to compare the responses of Glutatione Transferases (GSTs) in the gills and hepatopancreas of Venerupis philippinarum to microcystins (MCs) toxicity. In this way, using the cytosolic fraction, the enzymatic activity of GSTs, superoxide dismutase (SOD), serine/threonine protein phosphatases (PPP2) along with the gene expression levels of four GST isoforms (pi, mu, sigma1, sigma2) were investigated in both organs of the clams exposed for 24 h to 10, 50 and 100 μg L(-1) of MC-LR. Cytosolic GSTs (cGSTs) from both organs of the high dose exposed clams were purified by glutathione-agarose affinity chromatography, characterized kinetically and the changes in the expression of cGSTs of the gills identified using a proteomic approach. MC-LR caused an increase in GST enzyme activity, involved in conjugation reactions, in both gills and hepatopancreas (100 μg L(-1) exposure). SOD activity, an indicator of oxidative stress, showed significantly elevated levels in the hepatopancreas only (50 and 100 μg L(-1) exposure). No significant changes were found in PPP2 activity, the main target of MCs, for both organs. Transcription responses revealed an up-regulation of sigma2 in the hepatopancreas at the high dose, but no significant changes were detected in the gills. Kinetic analysis evidenced differences between gills of exposed and non-exposed extracts. Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs. Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs.

No MeSH data available.


Related in: MedlinePlus