Investigation on the phagocytosis operated by the mussel (Mytilus galloprovincialis) hemocytes using the 1,2,3-dihydrorhodamine as fluorescent probe

Different fluorescence techniques, such as flowcytometry, micromethod fluorimetry and confocal laserscanning microscopy have been applied in the studyof cellular defense system of Mytilus galloprovincialis.The phagocytosis stimuli was represented by theyeast cells (zymosan), whereas the fluorescent probeutilised for the measuring the synthesis of the reactiveoxygen species (ROS) was the 1,2,3-dihydrorhodamine (DHR). Flow cytometrydistinguished three hemocyte sub-populations inmussel hemolymph, showing also the relation betweenhemocyte size, granularity and phagocytosis ability.Micromethod assay confirmed the respiratory burstproduced by the hemocytes whereas the use ofsuperoxide dismutase (SOD) and L-NG-Monomethyl52arginine citrate (L-NMMA) increased fluorescenceintensity. In addition, the confocal microscopy assaypermitted to valuate the oxidation of DHR, due to ROSsynthesis, inside the cellular organelles involved inphagocytosis. In conclusion, these innovatorytechniques could represent useful tools for valuatingthe immune system of marine invertebrates, both inresearch approach and in applied studies.[...]