Tissue distribution of neutral deoxyribonuclease (DNase) activity in the mussel Mytilus galloprovincialis.
The presence of neutral DNase activity in bivalves is reported for the first time. The enzyme activity in four tissues of the mussel Mytilus galloprovincialis was analyzed by three different methods (i) specific denaturating SDS-PAGE zymogram, (ii) sensitive single radial enzyme diffusion (SRED) assay and (iii) rapid and sensitive fluorimetric determination of DNase activity with PicoGreen. The fluorimetric assay was rapid and sensitive enough for determination of hydrolytic activity of dsDNA in mussel hepatopancreas, adductor, gills and mantle. Maximal activity in all mussel tissue extracts was obtained in the presence of Ca(2+) and Mg(2+) at pH 7.0 with dsDNA as substrate. The neutral DNase activity in mussel tissue decreases in order hepatopancreas, mantle>gills>adductor. The enzyme activity displays interindividual variability in particular tissue as well as variability among tissues within one specimen. In the hepatopancreas one to three distinct proteins expressing neutral, Ca(2+), Mg(2+)-dependent, DNase activity were detected by denaturating SDS-PAGE zymogram. This heterogeneity of neutral nucleases involved in DNA hydrolysis in hepatopancreas could reflect interindividual variability in mussel food utilization and nutrient requirement.
Bihari
Nevenka
N
Institute Ruder Bosković, Center for Marine Research, Rovinj, Croatia. bihari@cim.irb.hr
Fafandel
Maja
M
Perić
Lorena
L
D000818:Animals; D002118:Calcium / Q000378:metabolism; D003851:Deoxyribonucleases / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D008274:Magnesium / Q000378:metabolism; D049878:Mytilus / Q000201:enzymology*; D009928:Organ Specificity / Q000502:physiology
D003851:Deoxyribonucleases; D008274:Magnesium; D002118:Calcium