The crowding effect in Ancylostoma ceylanicum: density-dependent effects on an experimental model of infection

Serafim, Luciana Ribeiro; Silva, Jéssica Paôla Gonçalves da; Paiva, Nívia Carolina Nogueira de; Santos, Hudson Andrade dos; Silva, Maria da Gloria Quintão; Carneiro, Cláudia Martins; Dias, Sílvia Regina Costa; Rabelo, Élida Mara Leite

doi:10.1007/s00436-014-4151-y

Cited by 12 publications

(7 citation statements)

References 42 publications

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“…2006; Serafim et al . 2014 for lack of a crowding effect, see Holmes, 1962 b ; Poulin et al . 2003; for a positive effect of crowding see Kuris, 2003, 2005; Weinersmith et al .…”

Section: Introductionmentioning

confidence: 99%

Two's a crowd? Crowding effect in a parasitic castrator drives differences in reproductive resource allocation in singlevsdouble infections

2016

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The 'crowding effect' is a result of competition by parasites within a host for finite resources. Typically, the severity of this effect increases with increasing numbers of parasites within a host and manifests in reduced body size and thus fitness. Evidence for the crowding effect is mixed - while some have found negative effects, others have found a positive effect of increased parasite load on parasite fitness. Parasites are consumers with diverse trophic strategies reflected in their life history traits. These distinctions are useful to predict the effects of crowding. We studied a parasitic castrator, a parasite that usurps host reproductive energy and renders the host sterile. Parasitic castrators typically occur as single infections within hosts. With multiple parasitic castrators, we expect strong competition and evidence of crowding. We directly assess the effect of crowding on reproductive success in a barnacle population infected by a unique parasitic castrator, Hemioniscus balani, an isopod parasite that infects and blocks reproduction of barnacles. We find (1) strong evidence of crowding in double infections, (2) increased frequency of double infections in larger barnacle hosts with more resources and (3) perfect compensation in egg production, supporting strong space limitation. Our results document that the effects of crowding are particularly severe for this parasitic castrator, and may be applicable to other castrators that are also resource or space limited.

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“…2006; Serafim et al . 2014 for lack of a crowding effect, see Holmes, 1962 b ; Poulin et al . 2003; for a positive effect of crowding see Kuris, 2003, 2005; Weinersmith et al .…”

Section: Introductionmentioning

confidence: 99%

Two's a crowd? Crowding effect in a parasitic castrator drives differences in reproductive resource allocation in singlevsdouble infections

2016

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“…The anthelmintic activity of ketamine was confirmed in vivo using hamsters and BALB/c mice. Hamsters are permissive hosts for A. ceylanicum infection, and the pathogeny caused by these worms in hamsters is similarly caused in humans [23]. The BALB/c mice have been a good alternative model for studying early Ascaris spp., and initial events of infection and immunology are similar for the hosts of A. suum and A. lumbricoides [24].…”

Section: Discussionmentioning

confidence: 99%

Ketamine can be produced by Pochonia chlamydosporia: an old molecule and a new anthelmintic?

et al. 2020

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Background Infection by nematodes is a problem for human health, livestock, and agriculture, as it causes deficits in host health, increases production costs, and incurs a reduced food supply. The control of these parasites is usually done using anthelmintics, which, in most cases, have not been fully effective. Therefore, the search for new molecules with anthelmintic potential is necessary. Methods In the present study, we isolated and characterized molecules from the nematophagous fungus Pochonia chlamydosporia and tested these compounds on three nematodes: Caenorhabditis elegans; Ancylostoma ceylanicum; and Ascaris suum. Results The ethyl acetate extract showed nematicidal activity on the nematode model C. elegans. We identified the major substance present in two sub-fractions of this extract as ketamine. Then, we tested this compound on C. elegans and the parasites A. ceylanicum and A. suum using hamsters and mice as hosts, respectively. We did not find a difference between the animal groups when considering the number of worms recovered from the intestines of animals treated with ketamine (6 mg) and albendazole (P > 0.05). The parasite burden of larvae recovered from the lungs of mice treated with ketamine was similar to those treated with ivermectin. Conclusions The results presented here demonstrate the nematicidal activity of ketamine in vitro and in vivo, thus confirming the nematicidal potential of the molecule present in the fungus P. chlamydosporia may consist of a new method of controlling parasites.

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“…The anthelmintic activity of ketamine was con rmed in vivo using hamsters and BALB/c mice. Hamsters are permissive hosts for A. ceylanicum infection, and the pathogeny caused by these worms in hamsters is similarly caused in humans [23]. The BALB/c mice have been a good alternative model for studying early Ascaris spp., and initial events of infection and immunology are similar for the hosts de A. suum and A. lumbricoides [24].…”

Section: Discussionmentioning

confidence: 99%

Ketamine can be produced by Pochonia chlamydosporia: an old molecule and a new anthelmintic?

Ferreira

Machado

Furtado

et al. 2020

Preprint

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Background: Infection by nematodes is a problem for human health, livestock, and agriculture, as it causes deficits in host health, increases production costs, and incurs less food supply. The control of these parasites is usually done using anthelmintics, which, in most cases, have not been fully effective. Therefore, the search for new molecules with anthelmintic potential is necessary. Methods: In the present study, we isolated and characterized molecules from the nematophagous fungus Pochonia chlamydosporia and tested these compounds on three nematodes: Caenorhabditis elegans, Ancylostoma ceylanicum, and Ascaris suum. Results: The ethyl acetate extract showed nematicidal activity on the nematode model C. elegans. We identified the major substance present in two subfractions of this extract as ketamine. Then, we tested this compound on C. elegans and the parasites A. ceylanicum and A. suum using hamsters and mice as hosts, respectively. We did not find a difference between the animal groups when considering the number of worms recovered from the intestines of animals treated with ketamine (6 mg) and albendazole (P > 0.05). The parasite burden of larvae recovered from the lungs of mice treated with ketamine was similar to those treated with ivermectin. Conclusion: These results presented here demonstrated the nematicidal activity of ketamine in vitro and in vivo. Thus, confirming the nematicidal potential of the molecule present in the fungus P. chlamydosporia may consist of a new method of controlling parasites.

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The crowding effect in Ancylostoma ceylanicum: density-dependent effects on an experimental model of infection

Cited by 12 publications

References 42 publications

Two's a crowd? Crowding effect in a parasitic castrator drives differences in reproductive resource allocation in singlevsdouble infections

Two's a crowd? Crowding effect in a parasitic castrator drives differences in reproductive resource allocation in singlevsdouble infections

Ketamine can be produced by Pochonia chlamydosporia: an old molecule and a new anthelmintic?

Ketamine can be produced by Pochonia chlamydosporia: an old molecule and a new anthelmintic?

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