Veterinária
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11842
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Resultados da Pesquisa
Item In vitro ovicidal activity of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Pochonia chlamydosporia on Trichuris vulpis eggs(Veterinary Parasitology, 2010-08-27) Silva, A.R.; Araújo, J.V.; Braga, F.R.; Alves, C.D.F.; Frassy, L.N.The in vitro effect of four isolates of the nematophagous fungi Duddingtonia flagrans (AC001), Monacrosporium thaumasium (NF34a) and Pochonia chlamydosporia (VC1 and VC4) on the eggs of Trichuris vulpis was evaluated. One thousand eggs of T. vulpis were plated on Petri dishes with 2% water–agar with the fungal isolates grown and without fungus as control. After 7, 14 and 21 days 100 eggs were removed from each plate and classified according to the following parameters: type 1, lytic effect without morphological damage to eggshell; type 2, lytic effect with morphological alteration of embryo and eggshell; and type 3, lytic effect with morphological alteration of embryo and eggshell, besides hyphal penetration and internal egg colonization. P. chlamydosporia demonstrated ovicidal activity (p < 0.05) on the eggs of T. vulpis in the studied intervals presenting type 3 effect of 29.5% (VC1) and 36.5% (VC4), 59.5% (VC1) and 2.5% (VC4), 94.8% (VC1) and 2.95% (VC4) at 7, 14 and 21 days, respectively. The other fungi showed no type 3 effect. P. chlamydosporia should be a potential biological control agent of T. vulpis eggs.Item Comparative analysis of destruction of the infective forms of Trichuris trichiura and Haemonchus contortus by nematophagous fungi Pochonia chlamydosporia; Duddingtonia flagrans and Monacrosporium thaumasium by scanning electron microscopy(Veterinary Microbiology, 2011-01-10) Silva, A.R.; Araujo, J.V.; Braga, F.R.; Benjamim, L.A.; Souza, D.L.; Carvalho, R.O.The present study aimed to demonstrate by scanning electron microscopy (SEM) the in vitro predatory activity of nematophagous fungi Pochonia chlamydosporia (VC1 and VC4 isolates) Duddingtonia flagrans (AC001 isolate) and Monacrosporium thaumasium (NF34a isolate) on eggs of Trichuris trichiura and infective larvae (L3) of Haemonchus contortus. The work was divided into two experimental tests (A and B). In tests A and B, the predatory activity of nematophagous fungi P. chlamydosporia, D. flagrans and M. thaumasium on eggs of T. trichiura and H. contortus L3 was observed. After 6 h, in test A, isolates P. chlamydosporia (VC1 and VC4) had a role in destroying eggs of T. trichiura. For fungi D. flagrans and M. thaumasium the ovicidal activity on T. trichiura eggs was not observed. Test B showed that D. flagrans (AC001) and M. thaumasium (NF34a) were capable of predating H. contortus L3, but no predation by the fungus P. chlamydosporia was seen. These fungi can offer potential for the biological control of nematodes.Item Activity in vitro of fungal conidia of Duddingtonia flagrans and Monacrosporium thaumasium on Haemonchus contortus infective larvae(Journal of Helminthology, 2010-07-21) Silva, A.R.; Araujo, J.V.; Braga, F.R.; Alves, C.D.F.; Frassy, L.N.The objective of this work was to evaluate the predatory activity of the fungi Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34a) on Haemonchus contortus infective larvae (L3) in two experimental assays (A and B). In assay A, two treatments and one control were formed and kept for 7 days in Petri dishes with 2% water-agar. Each treatment consisted of 1000 H. contortus L3 and 1000 conidia of only one fungal isolate, and the control group consisted of 1000 L3, without fungus, with 10 repetitions per group. In assay B, 1000 conidia of one of the fungal isolates, AC001 or NF34a, were added to coprocultures made from 20 g of faeces collected from sheep naturally infected with H. contortus. At the end of the experiment, the Baermann method was used to count the non- predated larvae of all Petri dishes from treatment and control groups. In assay A, no difference was observed (P . 0.05) between the groups treated with AC001 and NF34a fungi. A difference was observed (P , 0.05) between the treated and control groups. The L3 reduction percentages at the end of the experiment were 87.75 and 85.57%, respectively, for the fungal isolates compared to the control group. In assay B, the reduction percentages for conidia of these isolates were 85.82 and 87.32%, respectively. The results obtained show that D. flagrans (AC001) and M. thaumasium (NF34a) were effective in the in vitro control of sheep H. contortus L3 and could be used in the biological control of this nematode.Item Optimizing protease production from an isolate of the nematophagous fungus Duddingtonia flagrans using response surface methodology and its larvicidal activity on horse cyathostomins(Journal of Helminthology, 2010-04-04) Braga, F.R.; Araújo, J.V.; Soares, F.E.F.; Araujo, J.M.; Genier, H.L.A.; Silva, A.R.; Carvalho, R.O.; Queiroz, J.H.; Ferreira, S.R.Protease production from Duddingtonia flagrans (isolate AC001) was optimized and the larvicidal activity of the enzymatic extract was evaluated on infective horse cyathostomin larvae (L3). Duddingtonia flagrans was grown in liquid medium with eight different variables: glucose, casein, bibasic potassium phosphate (K 2 HPO 4 ), magnesium sulphate (MgSO 4 ), zinc sulphate (ZnSO 4 ), ferrous sulphate (FeSO 4 ), copper sulphate (CuSO 4 ) and temperature. The Plackett– Burman analysis showed a significant influence of MgSO 4 , CuSO 4 and casein (P , 0.05) on protease production by D. flagrans in liquid medium. Central composite design indicated that the highest proteolytic activity was 39.56 U/ml as a function of the concentrations of casein (18.409 g/l), MgSO 4 (0.10 g/l) and CuSO 4 (0.50 mg/l). A significant difference (P , 0.01) was found for the larval number between the treated and control groups at the end of the experiment. A reduction of 95.46% in the number of free-living larvae was found in the treated group compared with the control. The results of this study suggest that protease production by D. flagrans (AC001) in liquid medium was optimized by MgSO 4 , CuSO 4 and casein, showing that the optimized enzymatic extract exerted larvicidal activity on cyathostomins and therefore may contribute to large-scale industrial production.