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Vibrio parahaemolyticus and V. harveyi cause detachment of the epithelium from the midgut trunk of the penaeid shrimp, Sicyonia ingentis.
Diseases of Aquatic Organisms (2004)
  • Gary G. Martin, Occidental College
  • Nicole Rubin
  • Erica Swanson
Abstract
Shrimp Sicyonia ingentis were either injected with Vibrio parahaemolyticus (104 CFU) or V. harveyi (106 CFU) or immersed in ASW containing either species at 105 CFU ml-1. These densities were shown in preliminary experiments to kill approximately half the population by 7 d. On Day 7, surviving shrimp were classified as either diseased or apparently healthy, and their midgut trunks (MGT) were examined by light and electron microscopy. All shrimp immersed in ASW containing either species of Vibrio showed detachment of the epithelium in the MGT. In shrimp injected with either species of Vibrio, epithelial detachment was common in diseased shrimp but not in apparently healthy animals. Experiments with live shrimp were supported by in vitro experiments where MGTs were removed, tied off at both ends, and injected with either pathogenic bacteria (V. parahaemolyticus or V. harveyi), non-pathogenic bacteria (Bacillus subtilis or Escherichia coli), or ASW. After 2 h incubations in ASW at 15°C, the MGTs were processed and examined. The epithelium consistently detached from isolated MGTs injected with either species of Vibrio, but not from MGTs injected with non-pathogenic bacteria or ASW. Because the MGT epithelium secretes the peritrophic membrane, loss of the epithelium eliminates 2 layers that may restrict penetration of ingested pathogens into the shrimp body and may disrupt the osmoregulatory function of the MGT. A second finding was that fixed, large-granule hemocytes associated with the basal lamina degranulated in the presence of the 2 species of Vibrio, but not with the non-pathogenic bacteria or ASW. These blood cells may help fight specific bacteria penetrating the MGT.
Keywords
  • Shrimp,
  • Vibriosis,
  • Midgut trunk,
  • Hemocytes
Disciplines
Publication Date
July 5, 2004
Citation Information
Gary G. Martin, Nicole Rubin and Erica Swanson. "Vibrio parahaemolyticus and V. harveyi cause detachment of the epithelium from the midgut trunk of the penaeid shrimp, Sicyonia ingentis." Diseases of Aquatic Organisms Vol. 60 Iss. 1 (2004)
Available at: http://works.bepress.com/gary_martin/11/