Protamine-like proteins' analysis as an emerging biotechnique for cadmium impact assessment on male mollusk Mytilus galloprovincialis (Lamarck 1819)

Acta Biochim Pol. 2018;65(2):259-267. doi: 10.18388/abp.2017_2533. Epub 2018 Jun 15.


Here we report the industrial pollution effects due to cadmium on the reproductive health of Mytilus galloprovincialis. Mussels were removed from the biofouling of a Conatex panel after one year exposition at a polluted site near a disposal metallurgical factory. A high cadmium bioaccumulation was observed in the testis of mussels housed at the polluted site, with respect to a control site, as determined by inductively coupled plasma-mass spectrometry, along with a 10 fold increase in metallothionein 20 kDa gene (mt20) expression levels determined by qPCR. Furthermore, mussels transferred into laboratory tanks from the reference site, and exposed to 1.5, 5 and 10 µM CdCl2, revealed a 1.7, 3.2 and 4.5 fold expression increase in the testis mt20, respectively, and a positive correlation with cadmium bioaccumulation was found. To evaluate a potential detrimental risk of such alterations on spermatozoa, we carried out electrophoretic analyses on their protamine-like proteins. As determined by AU-PAGE, after 1.5 µM CdCl2 exposure, protamine-like proteins also display major alterations with respect to those obtained after 5 and 10 µM CdCl2 exposure. All protamine-like proteins isolated from the polluted biofouling were in an aggregated form and displayed the same reduced DNA binding affinity of the protamine-like proteins obtained after 1.5 µM CdCl2 as demonstrated EMSA with sperm genomic DNA. Our results contribute to the studies concerning cadmium induced testis alterations and highlight protamine-like proteins' analysis as an emerging biotechnique for cadmium impact assessment on Mytilus galloprovincialis, for the sensitivity of the in vivo and in vitro changes of protamine-like proteins' state and their DNA binding affinity.

Keywords: Mytilus galloprovincialis; Protamine-like-proteins; cadmium impact assessment; emerging biotechniques; spermatozoa; testis metallothionein.

MeSH terms

  • Animals
  • Cadmium / pharmacology*
  • DNA / metabolism
  • Male
  • Metallothionein / metabolism
  • Mytilus
  • Protamines / analysis*
  • Protamines / metabolism
  • Reproduction / drug effects
  • Testis / drug effects
  • Water Pollutants, Chemical / analysis
  • Water Pollutants, Chemical / pharmacology*


  • Protamines
  • Water Pollutants, Chemical
  • Cadmium
  • DNA
  • Metallothionein