In vitro culture of intramolluscan stages of the avian schistosomeTrichobilharzia ocellata

Mellink, J. J.; Bovenkamp, Wim van den

doi:10.1007/bf00928336

Cited by 16 publications

(2 citation statements)

References 25 publications

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“…Although Bge-derived factors appear to be important for parasite development, the presence of a functional snail neuroendocrine system is not essential. In vitro culture studies with schistosome species parasitic to birds similarly indicate little, if any, neuroendocrine influence on sporocyst growth and development (28). The beneficial influence of Bge cells on schistosome development may be due to a classical peptide growth factor.…”

Section: Discussionmentioning

confidence: 99%

Continuous in vitro propagation and differentiation of cultures of the intramolluscan stages of the human parasite Schistosoma mansoni

Ivanchenko

Lerner²,

McCormick³

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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The metazoan parasitic blood f lukes, Schistosoma spp., infect over 200 million people worldwide and cause extensive human morbidity and mortality. Research strategies for development of anti-schistosomal agents are impeded by the organism's complex molluscan-mammalian life cycle, which limits experimental approaches and availability of material. We derived long-term continuously proliferative cultures of Schistosoma mansoni sporocysts capable of generating cercariae in vitro. Cultured organisms retained the ability to parasitize the host, and they exhibited developmental regulation of candidate stage-specific genes in the host-free culture system. Evidence for expression of a reverse transcriptase also was found in the cultured organisms, pointing to this activity as a possible mechanistic contributor to the dynamic relationship between the parasite and its hosts. Continuous in vitro propagation of the asexual sporocyst stage allows isolation of clonally derived parasite populations and provides a means to study schistosomal molecular genetics, metabolism, and evasion of host defenses.Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum create widespread disease in tropical developing countries (1). These parasites thwart attempts to produce practical and effective vaccines, and pharmacological approaches are problematic (2). Schistosome eggs are laid by females paired with males and residing in the vasculature of parasitized vertebrate hosts. To be successfully infective, eggs must penetrate the intestinal wall and pass in feces to fresh water. From these released eggs hatch free-swimming miracidia, the first larval form. Successful miracidia encounter and penetrate the appropriate species of snail and develop into sporocysts, the second larval from. In the following weeks, these primary sporocysts asexually generate first-generation and second-generation daughter sporocysts in the snail. From the later-generation sporocysts develop the third larval form, free-swimming cercaria. To be successfully infective in the human or other vertebrate host, cercaria must encounter and penetrate the skin of the host and undergo further changes to form schistosomula. These move through several further developmental stages, ultimately leading to sexual pairing in the veins of the parasitized host and egg production.Approaches to elucidate the mechanisms schistosomes employ to escape host immunity, as well as molecular genetic and pharmacological investigations, have been limited by the lack of an in vitro system for the continuous proliferative culture of the parasite in the absence of the host. Recently, Yoshino and colleagues (3, 4) have reported significant success in limited culture of the intramolluscan stages of S. mansoni and S.japonicum, but these techniques do not allow extended culture of proliferating sporocysts.Here we describe long-term cultures of S. mansoni in vitro and the development from the snail-infective miracidial stage, through generations of mother and daughter sporocysts, t...

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Section: Discussionmentioning

confidence: 99%

Continuous in vitro propagation and differentiation of cultures of the intramolluscan stages of the human parasite Schistosoma mansoni

Ivanchenko

Lerner²,

McCormick³

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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“…The fascicle of a mosquito is a structure developed by natural selection for penetration of animal skin or human skin. Fascicles are 30 μm wide and 2 mm long needle-like structures, which are used by female mosquitoes to penetrate the skin and obtain blood [13, 14]. …”

Section: Introductionmentioning

confidence: 99%

The effects of geometry on skin penetration and failure of polymer microneedles

Gittard

Chen

et al. 2013

Journal of Adhesion Science and Technology

130

100

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Microneedles are small-scale devices that may be used for drug delivery and biosensing. In this study, the forces required for mechanical failure, the modes of mechanical failure, as well as the mechanisms for microneedle penetration into porcine skin were examined. Microneedles produced from the acrylate-based polymer e-Shell 200 using an indirect rapid prototyping approach involving two-photon polymerization and poly(dimethylsiloxane) micromolding were found to possess sufficient strength for penetration of porcine skin. The failure forces were an order of magnitude greater than the forces necessary for full insertion into the skin. Bending was the most common form of failure; an increasing aspect ratio and a decreasing tip diameter were associated with lower failure forces. Video captured during skin penetration revealed that microneedle penetration into the skin occurred by means of a series of insertions and not by means of a single insertion event. Images obtained during and after skin penetration confirmed microneedle penetration of skin as well as transdermal delivery of lucifer yellow dye. These findings shed insight into the mechanisms of microneedle penetration and failure, facilitating design improvements for polymer microneedles.

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A simplified medium for the in vitro culture of mother sporocysts of the schistosomeTrichobilharzia ocellata

et al. 1990

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In vitro culture of intramolluscan stages of the avian schistosomeTrichobilharzia ocellata

Cited by 16 publications

References 25 publications

Continuous in vitro propagation and differentiation of cultures of the intramolluscan stages of the human parasite Schistosoma mansoni

Continuous in vitro propagation and differentiation of cultures of the intramolluscan stages of the human parasite Schistosoma mansoni

The effects of geometry on skin penetration and failure of polymer microneedles

A simplified medium for the in vitro culture of mother sporocysts of the schistosomeTrichobilharzia ocellata

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