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Abstract Freshwater snails of the genusBiomphalariaserve as intermediate hosts for the digenetic trematodeSchistosoma mansoni, the etiological agent for the most widespread form of intestinal schistosomiasis. As neuropeptide signaling in host snails can be altered by trematode infection, a neural transcriptomics approach was undertaken to identify peptide precursors inBiomphalaria glabrata, the major intermediate host forS.mansoniin the Western Hemisphere. Three transcripts that encode peptides belonging to the FMRF‐NH2‐related peptide (FaRP) family were identified inB.glabrata. One transcript encoded a precursor polypeptide (Bgl‐FaRP1; 292 amino acids) that included eight copies of the tetrapeptide FMRF‐NH2and single copies of FIRF‐NH2, FLRF‐NH2, and pQFYRI‐NH2. The second transcript encoded a precursor (Bgl‐FaRP2;347amino acids) that comprised 14 copies of the heptapeptide GDPFLRF‐NH2and 1 copy of SKPYMRF‐NH2. The precursor encoded by the third transcript (Bgl‐FaRP3; 287 amino acids) recapitulatedBgl‐FaRP2but lacked the full SKPYMRF‐NH2peptide. The three precursors shared a common signal peptide, suggesting a genomic organization described previously in gastropods. Immunohistochemical studies were performed on the nervous systems ofB.glabrataandB.alexandrina, a major intermediate host forS.mansoniin Egypt. FMRF‐NH2‐like immunoreactive (FMRF‐NH2‐li) neurons were located in regions of the central nervous system associated with reproduction, feeding, and cardiorespiration. Antisera raised against non‐FMRF‐NH2peptides present in the tetrapeptide and heptapeptide precursors labeled independent subsets of the FMRF‐NH2‐li neurons. This study supports the participation of FMRF‐NH2‐related neuropeptides in the regulation of vital physiological and behavioral systems that are altered by parasitism inBiomphalaria.
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This content will become publicly available on January 18, 2026
Localization of Cholecystokinin/Sulfakinin Neuropeptides in Biomphalaria glabrata , an Intermediate Host for Schistosomiasis
ABSTRACT Snails belonging to the genusBiomphalariaserve as obligatory intermediate hosts for the trematodeSchistosoma mansoni, the causative agent for the most widespread form of schistosomiasis. The simpler nervous systems of gastropod molluscs, such asBiomphalaria, provide advantageous models for investigating neural responses to infection at the cellular and network levels. The present study examined neuropeptides related to cholecystokinin (CCK), a major multifunctional regulator of central nervous system (CNS) function in mammals. A neural transcriptome generated from the CNS ofBiomphalaria alexandrinaincluded a transcript encoding two CCK‐related peptides, designatedBalex‐CCK1 (pEGEWSYDY(SO3H)GLGGGRF‐NH2) andBalex‐CCK2 (NYGDY(SO3H)GIGGGRF‐NH2). Peptide expression was examined inBiomphalaria glabrataat the mRNA level using the hybridization chain reaction (HCR) protocol and at the protein level using an antibody againstBalex‐CCK1. Expression was detected in 60–70 neurons distributed throughout the CNS, as well as in profuse fiber systems connecting the ganglia and projecting to the periphery. CCK‐like immunoreactive (CCKli) fibers were also observed on organs associated with the cardiorespiratory (nephridium, mantle, gill) and male reproductive systems. A comparison of mRNA and peptide localization suggested that CCK expression could be regulated at the level of translation. A potential role of these peptides in mediating responses to infection by larval schistosomes is discussed.
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- Award ID(s):
- 2217657
- PAR ID:
- 10568806
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Journal of Comparative Neurology
- Volume:
- 533
- Issue:
- 1
- ISSN:
- 0021-9967
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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