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Zinc effect on the sea urchin Paracentrotus lividus immunological competence
No full textPollution by heavy metals has become one of the most important problems in marine coastal areas as a consequence of anthropogenic inputs. Among metal contaminants, zinc, being considered not very toxic, is sometimes released into the sea in appreciable quantities and its concentration is loosely regulated.
In this work we analyzed the effects of a high zinc concentration on the sea urchin Paracentrotus lividus immune system. In particular, after 24 h of zinc treatment, we evaluated coelomocytes morphology and composition as well as the zinc influence on some humoral parameters such as hemolysis, lysozyme-like activity and antibacterial activity on Vibrio alginolyticus. Our results evidenced that the presence of zinc affected both cellular and acellular components of the sea urchin immune system. The P. lividus coelomocytes changed in morphology and number; moreover, the amebocytes changed from a petaloid to a filipodial-like shape and the red spherula cells increased in number. Among the considered humoral effectors lysozyme-like activity and antibacterial activity on V. alginolyticus decreased in short-term to zinc treatment. The modifications in the sea urchin immunological competence might give an early indication of disease susceptibility thus suggesting to consider the examined defence mechanisms as potential biological indicators of metal pollution
Effect of zinc on lysozyme-like activity of the seastar Marthasterias glacialis (Echinodermata, Asteroidea) mucus
No full textLysozyme represents the best characterized enzyme involved in the self-defense from bacteria. In this
study we analysed the effects of zinc on the lysozyme-like activity of the seastar Marthasterias glacialis
mucus. This activity, detected by measuring the cleared lysis area of dried Micrococcus lysodeikticus cell
walls on Petri dishes, was significantly reduced in presence of zinc. The results are discussed in the light
of elucidating the possible relationship between environmental contaminants and increased disease susceptibility
in seastars due to the decrease of antibacterial protection. The benefits of using the test of lysozyme
activity to monitoring environmental pollution are highlighted
Zinc effect on the immunological competence of the sea urchin Paracentrotus lividus gametes and embryos.
No full textAntibacterial protection in Marthasterias glacialis eggs: characterization of lysozyme-like activity
No full textLYSOZYME-LIKE AND TRYPSIN-LIKE ACTIVITIES IN THE CYST OF ARTEMIA FRANCISCANA KELLOG 1906. IS THERE A PASSIVE IMMUNITY IN A RESTING STAGE?
No full textEvidence of antibacterial and lysozyme-like activity in different larval stages of Paracentrotus lividus
No full textLarval lysate (four-armed stage) exerts a lysozyme-like and antibacterial activity directed against Vibrio alginolyticus and other bacterial strains. This lysozyme activity is dependent on the pH and ionic strength of the reacting medium and sample. The other larval stages (six-armed, eight-armed and a stage approaching metamorphosis) possess protection against bacteria as well. The highest antibacterial activity is present in the six-armed stage. These antibacterial compounds avoid exploitation by bacteria. Paracentrotus lividus larvae used in our experiments were laboratory-reared from specimens collected in 1993 in Porto Cesareo (Lecce, Italy)
Sewage-exposed marine invertebrates: survival rates and microbiological accumulation
Full text linklarge number of bacteria, including agents responsible
for diseases, characterise sewage-polluted seawaters.
Apart from standards for bathing waters and
bivalve aquaculture waters, there are no general microbiological
standards applicable to seawaters to help decide if
bacterial pollution is within acceptable ranges. This study
represents an attempt towards the issue of comparing the
susceptibility of different marine invertebrates subjected to
polluted seawater with a high microbial contamination. We
explored the survival rates and the microbiological accumulation
of mollusc bivalves, echinoderms and crustaceans
species exposed to sewage-polluted seawaters. Microbiological
analyses were performed on the polluted seawater and
on the homogenates of exposed and unexposed specimens.
Culturable bacteria (22 °C and 37 °C) and microbial pollution
indicators (total coliforms, Escherichia coli and intestinal
enterococci) were measured. When exposed to the
sewage-polluted seawater, the examined invertebrates
showed different survival rates. In the filter feeders, bacterial
densities at 22 °C and 37 °C rose after 96 h of exposure
to sewage. The highest concentrations of total coliforms and
intestinal enterococci were found in exposed bivalve Mytilus
galloprovincialis. The concentrations of bacteria growing at
37 °C were lower in the exposed deposit feeders compared
to the polluted seawater. Some yeasts were absent in several exposed species although these yeasts were present in the
polluted seawater. Our data suggest that the examined filter
feeders, given their capability to survive and accumulate
bacteria, may counteract the effects of sewage and restore
seawater qualit
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