Effect of the fungus Pochonia chlamydosporia on Echinostoma paraensei (Trematoda: Echinostomatidae)

Abstract

Echinostoma paraensei is a trematode of the genus Echinostoma that causes echinostomiasis in humans. The objectives of this study were to: evaluate the ovicidal activity of the nematophagous fungus Pochonia chlamydosporia (VC1 and VC4) on a solid medium 2% water-agar (2% WA) against E. paraensei eggs (assay A); evaluate ovicidal effect (destruction of eggs) of the isolate VC4 in supplemented culture media (assay B); and evaluate the ovicidal ability of the crude extract (VC4) on E. paraensei eggs (assay C). Eggs of E. paraensei (assay A) were placed in Petri dishes containing 2% WA with an isolate of the fungus P. chlamydosporia (VC1 and VC4) grown for 10 days, and without fungus as a control and evaluated regarding their destruction. In assay B, eggs of E. paraensei were placed in Petri dishes with different supplemented culture media and with VC4 isolate and the destruction of eggs was examined at the end of 25 days of interaction. In assay C, effects of the crude extract of P. chlamydosporia (VC4) on eggs were evaluated at the end of 7 days. In assay A, there was no difference (p>0.05) in ovicidal activity among the tested isolates (VC1 and VC4); however, the highest percentage for ovicidal activity (type 3 effect) was demonstrated by the isolate VC4. In assay B, the culture medium starch-agar showed the best results for the destruction of the eggs, with a percentage of 46.6% at the end of the assay. In assay C, the crude extract of VC4 was effective in the destruction of E. paraensei eggs, with a percentage reduction of 53%. The results of this study demonstrate that a rich culture medium with a greater availability of carbon and nitrogen may interfere directly in the predatory characteristics of ovicidal fungi.

Isolation of Ovicidal Fungi from Fecal Samples of Captive Animals Maintained in a Zoological Park

“…Prior investigations indicated the antagonistic activity of several fungal species belonging to the genera Fusarium and Trichoderma on eggs of the roundworm Toxocara canis [ 40 , 41 , 42 ]. The ovicidal activity of Pochonia chlamydosporia (formerly Verticillium chlamydosporium ) has been widely reported on eggs of trematodes ( Echinostoma paraensei , Fasciola hepatica ) and ascarids ( T. canis , P. equorum ) [ 19 , 20 , 43 ].…”

Interacción biológica de las enzimas producidas por hongos nematófagos saprófitos de suelo, contra huevos de Toxocara canis

“…Lelis y cols (2014) observaron las diferencias en el poder de destrucción de nematodos por el hongo P. chlamydosporia cuando éste crece en medio suplementado(46,6%) o sin suplemento (39,6%), y con el extracto crudo (53%). También destacan la velocidad de destrucción (25 días contra 7 con el extracto crudo), y enfatizan que este comportamiento pueda deberse a la alta concentración de enzimas en el extracto crudo203 .Hofstätter y cols. (2017), evaluaron el efecto de cuatro extractos fúngicos de cepas de P. lilacinus, T. harzianum y T. virens, en la maduración de huevos de Ancylostoma.…”

“…La literatura, en este punto, aún carece de información suficiente. Algunos autores sugieren la posibilidad de un "pool" de enzimas extracelulares de diferentes clases como quitinasas y proteasas, derivadas de diferentes hongos203 . Delgado Blandón y cols.…”