NITROSATIVE STRESS DUE TO HARMFULL ALGAE EXPOSITION IN THE BIVALVE MYTILUS EDULIS PLATENSIS

PUNTARULO S.; CABRERA, J.; GONZÁLEZ, PAULA MARIELA

Mar del Plata

Congreso; XVIII Congreso Latinoamericano de Ciencias del Mar-COLACMAR 2019 Asociación Latinoamericana de Investigadores en Ciencias del Mar-ALICMAR; 2019

Asociación Latinoamericana de Investigadores en Ciencias del Mar

The mussel Mytilus edulis platensis has a significant economic relevance since is oneof the most important sources of aquaculture in the region. As a filter feeder, M. edulisin spite of surviving biotoxin consumption, is a toxin carrier to humans. However, noinformation is currently available on the effects of the toxin on the nitrosativemetabolism in the mollusc. Hemocytes are the main effectors of the immune system.The hypothesis of this work was that nitrosative metabolism in the mussel hemocytes isenhanced in the presence of biotoxins during the harmful algal blooms (HAB) season(spring), as compared to hemocytes isolated during winter and summer time. Adultspecimens were collected from El Sótano, San Matías Gulf, Argentinean Sea.Superoxide anion (O2−) generation rate and damage to proteins were measuredspectrophotometrically and by western blot, respectively. O2− generation rate was notsignificantly different between winter and summer collected samples. The cellscollected during the spring season shown a 3-fold increased as compared to the othertwo seasons. Nitro-tyrosine relative abundance was significantly higher in springisolated cells (2.3-fold) as compared to winter and summer samples. The contentvalues of NO2−+NO3− were 81±16, 185±26 and 327±86 pmol/106 cell in winter, springand summer samples, respectively. Nitric oxide (NO) content was similar in hemocytesfrom animals collected in winter and summer time, but was 100% higher in samplescollected during spring, as compared to values obtained in winter and summer isolatedcells. In the HAB season the measured enhancement in NO2−+NO3− content was inbetween the values observed from winter and summer samples, following an apparentnormal natural rhythm. Thus, the content of these metabolites could respond to theexpected increase in nutrient availability during spring. On the other hand,measurements in NO content showed a clear increase only in the spring season thatcould be ascribed to the biotoxin presence which may stimulate both, the O2− and NO generation. Both molecules are known to react among them producing peroxynitritewhich may be responsible for the generation of nitro-tyrosine in proteins, as it wasobserved in the samples exposed to the biotoxins. Biotoxins seem as a contributingfactor to affect not only reactive oxygen species generation but also the nitrosativemetabolism. In this regard, the information on the changes in the NO content in thehemocytes is new and critical evidence that HAB-related toxins could affect reactivenitrogen species metabolism.