A POSSIBLE DEFENSE RESPONSE IN A COMMENSAL POLYCHAETE

Volume: 12Start Page: 65End Page: 6

DETERMINING THE AREA OF A GASTROPODS FOOT

Volume: 27Start Page: 93End Page: 9

BEHAVIORAL SPECIFICITY AND THE INDUCTION OF HOST RECOGNITION IN A SYMBIOTIC POLYCHETE

Volume: 141Start Page: 472End Page: 48

Impact of thermal loading and other water quality parameters on the epizootiology of Epistylis and Aeromonas infections of centrarchids. Progress report, September 1, 1976--July 30, 1977

During the past year, mounting evidence has been accumulated which indicates that the causative agent for red-sore disease among bass is the bacterium, Aeromonas hydrophila, and not the ciliate, Epistylis, as suggested in previous literature. Red-sore disease among bass in Par Pond continues to be highly seasonal with peak periods of infection occurring in spring and summer, with declining levels in fall and summer. The disease continues to be more prevalent among bass from thermally altered areas of the reservoir during all seasons except summer. Definite correlations were established between temperature, dissolved oxygen, pH, and Aeromonas density in the water column. Furthermore, the level of Aeromonas cell counts in the water column and incidence of the disease in bass was clearly established. Body condition of bass and probability of acquiring red-sore disease were also related. Histopathology of tissues from bass suggested lesions were produced by acute, lytic toxicity such as would be produced by bacterial exotoxins. Based on these observations, a tenative hypothesis is proposed which attempts to link various physico-chemical parameters, body condition of bass, probability of infection by Aeromonas, and stress

SPECIFICITY OF THE HOST-INDUCED NEGATIVE PHOTOTAXIS OF THE SYMBIOTIC WATER MITE, UNIONICOLA FORMOSA

Volume: 162Start Page: 163End Page: 17

POSITIVE AND HOST-INDUCED NEGATIVE PHOTOTAXIS OF THE SYMBIOTIC WATER MITE UNIONICOLA FORMOSA

Volume: 155Start Page: 599End Page: 60

Cross-resistance of largemouth bass to glochidia of unionid mussels

We tested whether host fish that acquired resistance to glochidia of one mussel species were cross-resistant to glochidia of other species. Largemouth bass (Micropterus salmoides) were primed with 4-5 successive infections of glochidia of Lampsilis reeveiana. The percentage of attached glochidia that survived and transformed to the juvenile stage (transformation success) was compared between primed fish and naïve controls. Transformation success of L. reeveiana, Lampsilis abrupta, Villosa iris, and Utterbackia imbecillis was significantly lower on primed fish (37.8%, 43.5%, 67.0%, and 13.2%, respectively) than on control fish (89.0%, 89.7%, 90.0%, and 22.2% respectively). Immunoblotting was used to analyze the binding of serum antibodies from primed fish with glochidia proteins. Antibodies bound to glochidia proteins of similar molecular weight from L. reeveiana and L. abrupta. Bound proteins of V. iris differed in molecular weight from those of the Lampsilis species. There was no binding to specific glochidia proteins of U. imbecillis or Strophitus undulatus. Our results indicate that host-acquired resistance can extend across mussel genera and subfamilies and might involve both specific and nonspecific mechanisms. Understanding the specificity of acquired resistance of hosts to glochidia could enhance understanding of the evolutionary and ecological relationships between mussels and their host fishes

Persistence of Host Response against Glochidia Larvae in Micropterus Salmoides

Host fish acquire resistance to the parasitic larvae (glochidia) of freshwater mussels (Unionidae). Glochidia metamorphose into juvenile mussels while encysted on host fish. We investigated the duration of acquired resistance of largemouth bass, Micropterus salmoides (Lacepède, 1802) to glochidia of the broken rays mussel, Lampsilis reeveiana (Call, 1887). Fish received three successive priming infections with glochidia to induce an immune response. Primed fish were held at 22-23 degrees C and were challenged (re-infected) at intervals after priming. Metamorphosis success was quantified as the percent of attached glochidia that metamorphosed to the juvenile stage and were recovered alive. Metamorphosis success at 3, 7, and 12 months after priming was significantly lower on primed fish (26%, 40%, and 68% respectively) than on control fish (85%, 93%, and 92% respectively). A second group of largemouth bass was similarly primed and blood was extracted. Immunoblotting was used to detect host serum antibodies to L. reeveiana glochidia proteins. Serum antibodies were evident in primed fish, but not in naive control fish. Acquired resistance of host fish potentially affects natural reproduction and artificial propagation of unionids, many of which are of conservation concern