Chemical Aspects of the Ecology of Platyhelminths

Schwabe, Calvin W.; Kilejian, Araxie

doi:10.1016/b978-0-12-395535-7.50024-3

Cited by 5 publications

(4 citation statements)

References 429 publications

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“…Since it was first described nearly four decades ago, there have been conflicting reports about the biological relevance of HA in these parasites. On the one hand, the tissue level of HA in S. mansoni appears to be low, lower than that of other parasitic platyhelminths (Schwabe and Kilejian 1968; Perez-Keep and Payares 1978; Eriksson et al, 1996). This has made it difficult to visualize histaminergic neurons in situ .…”

Section: Discussionmentioning

confidence: 77%

“…HA levels vary substantially among parasitic flatworms. Some species, including the bloodfluke Schistosoma mansoni , have low tissue levels of HA, whereas other parasites, notably the amphibian trematode, Haplometra cylindracea store HA at very high concentrations (Mettrick and Telford, 1963; Schwabe and Kilejian, 1968; Ercoli et al, 1985; Eriksson et al, 1996). The reason for this variation is not clear.…”

Section: Introductionmentioning

confidence: 99%

“…It is possible the rate of synthesis is low or that HA is rapidly degraded once it is released. Schistosoma mansoni was reported to possess histaminase (diamine oxidase) activity, an enzyme that breaks down HA (Schwabe and Kilejian, 1968). A high rate of HA catabolism could explain why the basal level of this amine is so low in these animals.…”

Section: Introductionmentioning

confidence: 99%

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Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

El-Shehabi¹,

Vermeire²,

Yoshino³

et al. 2009

Experimental Parasitology

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A Schistosoma mansoni G-protein coupled receptor (SmGPCR) was previously cloned and shown to be activated by the biogenic amine, histamine. Here we report a first investigation of the receptor’s subunit organization, tissue distribution and expression levels in different stages of the parasite. A polyclonal antibody was produced in rabbits against the recombinant third intracellular loop (il3) of SmGPCR. Western blot studies of the native receptor and recombinant protein expressed in HEK293 cells showed that SmGPCR exists both as a monomer (65 kDa) and an apparent dimer of ≈130 kDa These species were verified by immunoprecipitation of SmGPCR from S. mansoni extracts, using antibody that was covalently attached to agarose beads. Further investigation determined that the SmGPCR dimer was resistant to treatment with various detergents, 4 M urea and 0.1 M DTT but could be made to dissociate at acidic pH, suggesting the dimer is non-covalent in nature. Confocal immunofluorescence studies revealed significant SmGPCR immunoreactivity in sporocysts, schistosomula and adult worms but not miracidia. SmGPCR was found to be most widely expressed in the schistosomula, particularly the tegument, the subtegumental musculature and the acetabulum. In the adult stage we detected SmGPCR immunofluorescence mainly in the tubercles of male worms and, to a lesser extent, the body wall musculature. Localization in sporocysts was mainly confined to the tegument and cells within parenchymal matrices. A realtime quantitative reverse-transcription PCR analysis revealed that SmGPCR is upregulated at the mRNA level in the parasitic stages compared to the free-living miracidium and cercariae, and it is particularly elevated during early sporocyst and schistosomula development. The results identify SmGPCR as an important parasite receptor with potential functions in muscle and the tegument of S. mansoni.

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Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

El-Shehabi¹,

Vermeire²,

Yoshino³

et al. 2009

Experimental Parasitology

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“…It is probable that the processes used by parasites to locate and infect hosts are similar to the processes used by free-living organisms to exploit their environment. Reviews on host-finding include Ulmer (1971); Chernin (1974); Cheng (1967); Schwabe & Kilejian (1968); Canning & Wright (1972) and Haas (1988). Maclnnis (1976) identified three sources of signals which modify the behaviour of parasites.…”

Section: Host Locationmentioning

confidence: 99%

The ecology of host-finding behaviour and parasite transmission: past and future perspectives

Rea

Irwin

1994

Parasitology

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Host location by parasites can be achieved by either active or passive mechanisms. In spite of their significance, the efficacy of these methods has been little researched. High fecundity in parasites is discussed in terms of the role it plays in dispersal and transmission. Some concepts developed by mainstream behavioural ecologists are outlined and their relevance to parasitology is indicated. 'Reproductive value' is recommended as an appropriate measure of the costs and benefits of behavioural cts. Although costs of reproduction have been rarely studied in parasites, they are likely to occur in cosexual insects, nematodes and crustaceans. Experiments using captive hosts and/or in vitro cultivation could help in the construction of realistic optimality models. We suggest that r- and K-selection theory could assist in the study of the evolution of parasite behaviour. We discuss how parasite populations are dispersed and controlled and consider the implications of overdispersion. We outline three sources of signals to which parasites may respond and suggest that understanding evolutionary mechanisms and community organisation of parasites and hosts requires evaluation of fundamental behavioural responses to environmental signals. The study of closely related groups of parasites and their hosts may advance our knowledge of the evolution of parasite life cycles and the evolutionary costs and benefits of behavioural acts.

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Schistosoma mansoni: Neurotransmitters and the mobility of cercariae and schistosomules

Ercoli¹,

Payares²,

Nunez³

1985

Experimental Parasitology

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Chemical Aspects of the Ecology of Platyhelminths

Cited by 5 publications

References 429 publications

Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

The ecology of host-finding behaviour and parasite transmission: past and future perspectives

Schistosoma mansoni: Neurotransmitters and the mobility of cercariae and schistosomules

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