Effects of the digenea Proctoeces lintoni (Fellodistomidae) in the proportion of hemolymphatic cells in Fissurella crassa (Mollusca: Archaeogastropoda)

Abstract

The progenetic digenea Proctoeces lintoni Siddiqi & Cable, 1960 (Fellodistomidae) is a common parasite in the gonads of key-hole limpets of the genus Fissurella (Archaeogastropoda). This helminth causes partial castration in Fissurella crassa (ME Oliva 1992 Mem Inst Oswaldo Cruz 87: 34-42) and fecundity (expressed as egg/mm shell) of infected individuals is dramatically reduced when intensity of infection increases (ME Oliva & AA Vega 1994 Mem Inst Oswaldo Cruz 89: 225). These effects may strongly affect the populations due to decreased fecundity. Despite the impact of the helminth, no host response seems to occur.To examine the possibility that primary cellular reactions against the helminths could be developed, here we analyze changes in the proportion of hemocytes (granulocytes and hyalinocytes) in infected and non-infected key hole limpet F. crassa, obtained from the intertidal zone of Caleta Constitución, northern Chile (23°25'S 70°35´W). Live key-hole limpets were brought to the laboratory and kept in 60 l glass containers at room temperature. A total number of 83 specimens (ranging 23.2 to 78.8 mm total length) were collected and measured (to the nearest 0.1 mm) and their shells were carefully rinsed with distilled water to remove salts, after which all the specimens were dissected, sexed, and presence of parasites was quantified. Thirty non-infected and 30 infected (1 to 27 parasites) key hole limpet, in the range of 30 to 60 mm in total length, were selected for the analysis. Hemolymph was extracted directly from the heart with a syringe after cardiac punction. At least 100 µl of hemolymph of individual key hole limpets was centrifuged (5000 G * 15 min at 4°C ) and smear were prepared on glass standard slides. Then the slides were stained with May Grunwald-Giemsa and at least 200 cells were counted to determine the relative proportion of each one of the two cellular types, hyalinocytes and granulocytes, identifiable in according to MA Barracco et al. (1993 Mem Inst Oswaldo Cruz 88: 73-83). Key-hole limpets were thus assigned into three categories: non infected, low infection (1 to 9 parasites, average = 4.4, SD = 2.6, n = 14 ) and strong infection (> 10 parasites, average 16.3, SD = 5.1, n = 16). Mean size of key hole limpets (Table) differed significantly among the categories (F 2,57 = 59.7, P < 0.001), but proportion of granulocytes (after arcsine transformation) is not affected by host size (r = 0.015, P = 0.937, n = 30). One-way ANOVA applied to arcsine-transformed data of proportion of granulocytes in healthy males and females revealed non significant differences between the sexes (males 66.4%, females 66.8%, F 1,28 = 0.146, P = 0.705). Thus we concluded that both, host size and host sex do not affect the proportion of granulocytes. Proportion of hyalinocytes and granulocytes in non-infected, low infected and strong infected mollusks is shown in the Table. A one-way ANOVA shows that proportion of granulocytes differed significantly among the above categories (F 2,57 = 58.3, P = 0.001). Further,...

Ultrastructural investigations of vitellogenesis and oogenesis of Proctoeces sp. infesting Platycephalus indicus fishes caught from Alataka Harbor, Suez Gulf, Egypt.

“…Among 18,000 digenean species described by Bray et al, (2002), vitellogenesis of only 20 species were studied (Swiderski et al, 2011). Family fellodistomidae embraces relatively large sized species infecting the digestive and reproductive system of bivalves and bony fishes (Oliva and Vásquez, 1999). The digenea Proctoeces lintoni is a common parasite in the gonads of key-hole limpets of Heavy infestations with the intestinal parasite Proctoeces sp.…”