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T4 11:00 Tissue transplants in the snail, Biomphalaria glabrata
Abstracts of the 7th Congress of the ISDCI: Session T
230
T3 IO:45 USING
NESTED
PCR TO INVESTIGATE THE FATE OF SCHISTOSOMA MANSONI IN SUSCEPTIBLE AND RESISTANT LABORATORY POPULATIONS OF BIOMPHALARZA GLABRATA B. Hanelt, W. M. El Maznyt, M. H. Mansour’, and E. S. Lokel. Department of Biology, University of New Mexico, Albuquerque NM 8713 1, USA. tFaculty of Science, Zoology Department, Cairo University, Egypt.
A nested PCR technique has been developed that allows the sensitive detection of the 18s rDNA gene of sporocysts of S. mansoni developing in both Biomphalaria glabrata and B. alexandrina. It was of interest to determine if the same procedure could be used to trace the fate of this parasite in B. gZabrata known to be susceptible or actively resistant to infection. Juvenile snails from the M-line (susceptible) or from 13- 16-Rl and Salvador Bahia strains (both resistant) were exposed to either 2-3 or 10 5. mansoni miracidia. DNA was extracted from individual snails at varying times postexposure (l-48 days). Preliminary results indicate that regardless of miracidial dose, the nested PCR protocol is unable to detect the presence of intact S. mansoni 18s sequencesby three days postinfection in either resistant strain of B. glabrata. Exposed resistant snails were also negative at most subsequent sampling times. In contrast, in M line snails, for either miracidial dose, an 5’. mansoni signal could be amplified using the nested approach by one day post infection and thereafter. This approach may be useful in trying to assessthe degree of compatibility of natural snail populations with local schistosome species. Additional methods for detecting the presence of developing S. mansoni sporocysts without having to kill the snail host will also be discussed. (Schistosome Research Program, USAID, 263-0140.2).
T4 1190 TISSUE J&J.
TRANSPLANTS
IN THE SNAIL,
BIOMPHALARZA GLABRATA
Sullivgu Depamnrat of Biology, University of the lucamate Word, San htonio, TX 78209, USA
Earlier studies have shown long-term survival of heterotopic allografis of amoebocyteproducing organ (APO), and of heart allografis, congeneric xenografis, and Helisoma xenografts in Biomphalaria gIabrata. These observations have been extended to several other types of aliogeneic tissues, which also show evidence of continued physiological activity at 60 days post implantation: kidney, mantle, albumin gland, digestive gland, gonad, and brain. As reported previously, APO allografls from 13-16-R I B. glabraru, which are resistant to infection with Schistosoma mattsoni, confer schistosome resistance in about 30% of normally susceptible M-line snails. Snails with transferred resistance (TR) show increased killing of primary sporocysts in their tentacles. In an effort to obtain higher levels of TR and to elucidate its mechanism, which could involve synthesis of soluble resistance factors and/or production of hemocytes with the resistant phenotype, a number of experimental variables have been examined: effects of donor size, donor strain, donor “priming’” by exposure to miracidia, double implants, and allografis of the other tissues listed above, which could serve as sources of putative soluble factors or hemocytes. Unexpectedly, no increase in TR occurred with double APO implants, and lower levels of transferred resistance were obtained with APOs from larger donors (> I4 mm in shell diameter). Prior exposure of donors to miracidia appears to be necessary for their APOs to confer TR. None of the other tissues tested effect TR. Supported by NIH grant AI 35772.
230
T3 IO:45 USING
NESTED
PCR TO INVESTIGATE THE FATE OF SCHISTOSOMA MANSONI IN SUSCEPTIBLE AND RESISTANT LABORATORY POPULATIONS OF BIOMPHALARZA GLABRATA B. Hanelt, W. M. El Maznyt, M. H. Mansour’, and E. S. Lokel. Department of Biology, University of New Mexico, Albuquerque NM 8713 1, USA. tFaculty of Science, Zoology Department, Cairo University, Egypt.
A nested PCR technique has been developed that allows the sensitive detection of the 18s rDNA gene of sporocysts of S. mansoni developing in both Biomphalaria glabrata and B. alexandrina. It was of interest to determine if the same procedure could be used to trace the fate of this parasite in B. gZabrata known to be susceptible or actively resistant to infection. Juvenile snails from the M-line (susceptible) or from 13- 16-Rl and Salvador Bahia strains (both resistant) were exposed to either 2-3 or 10 5. mansoni miracidia. DNA was extracted from individual snails at varying times postexposure (l-48 days). Preliminary results indicate that regardless of miracidial dose, the nested PCR protocol is unable to detect the presence of intact S. mansoni 18s sequencesby three days postinfection in either resistant strain of B. glabrata. Exposed resistant snails were also negative at most subsequent sampling times. In contrast, in M line snails, for either miracidial dose, an 5’. mansoni signal could be amplified using the nested approach by one day post infection and thereafter. This approach may be useful in trying to assessthe degree of compatibility of natural snail populations with local schistosome species. Additional methods for detecting the presence of developing S. mansoni sporocysts without having to kill the snail host will also be discussed. (Schistosome Research Program, USAID, 263-0140.2).
T4 1190 TISSUE J&J.
TRANSPLANTS
IN THE SNAIL,
BIOMPHALARZA GLABRATA
Sullivgu Depamnrat of Biology, University of the lucamate Word, San htonio, TX 78209, USA
Earlier studies have shown long-term survival of heterotopic allografis of amoebocyteproducing organ (APO), and of heart allografis, congeneric xenografis, and Helisoma xenografts in Biomphalaria gIabrata. These observations have been extended to several other types of aliogeneic tissues, which also show evidence of continued physiological activity at 60 days post implantation: kidney, mantle, albumin gland, digestive gland, gonad, and brain. As reported previously, APO allografls from 13-16-R I B. glabraru, which are resistant to infection with Schistosoma mattsoni, confer schistosome resistance in about 30% of normally susceptible M-line snails. Snails with transferred resistance (TR) show increased killing of primary sporocysts in their tentacles. In an effort to obtain higher levels of TR and to elucidate its mechanism, which could involve synthesis of soluble resistance factors and/or production of hemocytes with the resistant phenotype, a number of experimental variables have been examined: effects of donor size, donor strain, donor “priming’” by exposure to miracidia, double implants, and allografis of the other tissues listed above, which could serve as sources of putative soluble factors or hemocytes. Unexpectedly, no increase in TR occurred with double APO implants, and lower levels of transferred resistance were obtained with APOs from larger donors (> I4 mm in shell diameter). Prior exposure of donors to miracidia appears to be necessary for their APOs to confer TR. None of the other tissues tested effect TR. Supported by NIH grant AI 35772.