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The protistan parasite Perkinsus marinus is resistant to selected reactive oxygen species

Eric J Schott1, Wolf T Pecher, Florence Okafor

  • 1Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 East Pratt Street, Baltimore, MD 21202, USA.

Experimental Parasitology
|March 3, 2004
PubMed

Insights

The parasite Perkinsus marinus resists reactive oxygen species (ROS) and hydrogen peroxide (H2O2) better than Vibrio splendidus. This resistance may explain how P. marinus survives oyster immune defenses.

Area of Science:

  • Marine biology
  • Parasitology
  • Immunology

Background:

  • Perkinsus marinus causes significant losses in oyster populations.
  • Oyster hemocytes typically produce reactive oxygen species (ROS) during phagocytosis.
  • P. marinus trophozoites are engulfed by hemocytes without the usual ROS burst.

Purpose of the Study:

  • To investigate the susceptibility of P. marinus to ROS.
  • To compare ROS resistance between P. marinus and Vibrio splendidus.
  • To elucidate mechanisms of ROS detoxification by P. marinus.

Main Methods:

  • In vitro exposure of P. marinus and V. splendidus to superoxide, hydrogen peroxide (H2O2), and hypochlorite.
  • Assessing degradation of H2O2 by P. marinus trophozoites.
  • Enzyme activity assays on P. marinus extracts for catalase and peroxidase.

Main Results:

  • P. marinus showed significantly lower susceptibility to superoxide and H2O2 compared to V. splendidus.
  • P. marinus exhibited equal sensitivity to hypochlorite as V. splendidus.
  • P. marinus trophozoites degraded H2O2 but lacked catalase activity.
  • P. marinus extracts demonstrated ascorbate-dependent peroxidase activity.

Conclusions:

  • P. marinus possesses a high resistance to specific ROS, particularly superoxide and H2O2.
  • This resistance is likely a key factor in P. marinus survival against oyster immune responses.
  • Ascorbate-dependent peroxidase activity may play a crucial role in ROS detoxification by P. marinus.

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