Navegando por Autor "Lima, Walter dos Santos"

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Atividade larvicida do extrato bruto enzimático do fungo Duddingtonia flagras sobre larvas de primeiro estádio de Angiostrongylus vasorum
(Revista da Sociedade Brasileira de Medicina Tropical, 2011-01-05) Braga, Fabio Ribeiro; Araujo, Juliana Milani; Tavela, Alexandre de Oliveira; Araújo, Jackson Victor de; Soares, Filippe Elias de Freitas; Geniêr, Hugo Leonardo André; Lima, Walter dos Santos; Mozzer, Lanuze Rose; Queiroz, José Humberto de
Angiostrongylus vasorum é um nematóide que parasita cães domésticos e eventualmente o homem. O objetivo deste trabalho foi observar a atividade predatória in vitro do extrato bruto enzimático do fungo Duddingtonia flagrans sobre larvas de primeiro estádio A. vasorum em condições laboratoriais no meio ágar-água 2%. Ao final do experimento, os percentuais de redução das L1 de A. vasorum observados foram de: 53,5% (24h) e 71,3% (48h) O extrato bruto enzimático do fungo D. flagrans destruiu in vitro as L1, podendo ser utilizado como controle biológico desse nematóide.
In vitro activity of a serine protease from Monacrosporium thaumasium fungus against first-stage larvae of Angiostrongylus vasorum
(Parasitology Research, 2012-01-10) Braga, Fabio R.; Araújo, Jackson V.; Soares, Filippe E. F.; Lima, Walter dos Santos; Mozer, Lanuze R.; Queiróz, José H.
A serine protease from the nematophagous fungus Monacrosporium thaumasium (NF34a) was purified, partially characterized and tested in vitro in control of the first larval stage of Angiostrongylus vasorum. NF34a grew in liquid culture medium, producing its crude extract that was purified by ion exchange chromatography. The fractions with high protease activity were collected in a pool, and elution of proteases was monitored by enzymatic assay and protein content. Purification steps were monitored by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Protease activity was determined under different pH and temperature conditions, and the inhibitor effects of metal ions and phenylmethylsulfonyl fluoride (PMSF) were assessed. In an experimental test, the infection process of NF34a on first-stage larvae of A. vasorum was investigated. A purified serine protease (Mt1) was identified, with an approximate molecular mass of 40 kDa and apparent homogeneity in SDS-PAGE, having optimal activity at pH 7.0 to 8.0 and temperature of 60°C. Mg2+ and Zn2+ partially inhibited the activity of Mt1 while PMSF inhibited it completely. Mt1 production was observed when NF34a was grown using first-stage larvae of A. vasorum as the only source of carbon and nitrogen. These results show that the enzyme may have a possible role in the infection process of the larvae. In the in vitro test of applicability against A. vasorum L1, we observed a reduction in the number of larvae of 23.9% (p < 0.05) in the group treated with Mt1 compared with the control group. However, even this low reduction demonstrates that the Mt1 is important in the infection process.
In vitro predatory activity of conidia of fungal isolates of the Duddingtonia flagrans on Angiostrongylus vasorum first-stage larvae
(Revista da Sociedade Brasileira de Medicina Tropical, 2011-09-30) Braga, Fabio Ribeiro; Araujo, Juliana Milani; Araújo, Jackson Victor de; Soares, Filippe Elias de Freitas; Tavela, Alexandre de Oliveira; Frassy, Luiza Neme; Lima, Walter dos Santos; Mozzer, Lanuze Rose
Angiostrongylus vasorum is a nematode that parasitizes molluscs, dogs, and even man. The objective was to evaluate the predatory activity of the conidia of two fungal isolates of Duddingtonia flagrans (AC001 and CG722) on first-stage larvae (L1) of A. vasorum in laboratory conditions. At the end of the experiment, there were significant reductions (p<0.01) of 74.5% and 63.2%, on average, in the A. vasorum L1 recovered in the AC001 and CG722 treatment conditions, respectively. The two isolates of fungi were efficient in the capture and destruction of A. vasorum L1.
The nematophagous fungus Monacrosporium thaumasium and its nematicidal activity on Angiostrongylus vasorum
(Revista Iberoamericana de Micología, 2013-09-24) Soares, Filippe Elias de Freitas; Braga, Fabio Ribeiro; Araújo, Jackson Victor de; Lima, Walter dos Santos; Queiroz, José Humberto de
The dog acts as a reservoir and environmental disseminator of potentially zoonotic parasites. The objective of this work was to study the fungus Monacrosporium thaumasium regarding its nematicidal potential in laboratory trials and its proteolytic profile. The in vitro test was carried out through two assays (A and B). In assay A, conidia of the fungus N34a were added in positive coprocultures for Angiostrongylus vasorum. In assay B, crude extract (treated group) and distilled water (control group) were added to coprocultures. Next, the proteolytic profile of crude extract of the nematophagous fungus M. thaumasium (NF34a) was revealed by performing a zymogram. There was a reduction (p < 0.01) in the averages of larvae recovered from the treated groups (conidia and crude extract) in relation to control groups. The zymogram suggested that the nematophagous fungus M. thaumasium produces a protease of approximately 40 kDa. The results of this work confirm that the conidia as well as the crude extract of the fungus M. thaumasium may be used to control A. vasorum L1. The proteolytic profile suggested the presence of one protease (Mt1) of approximately 40 kDa that in the future may be used in biological control of L1 of this nematode.
Optimization of protease production by the fungus Monacrosporium thaumasium and its action againstAngiostrongylus vasorum larvae
(Revista Brasileira de Parasitologia Veterinária, 2012-09-20) Soares, Filippe Elias de Freitas; Queiroz, José Humberto de; Braga, Fabio Ribeiro; Araújo, Jackson Victor de; Lima, Walter dos Santos; Mozzer, Lanuze Rose
The objectives of this study were to optimize protease production from the nematophagous fungus Monacrosporium thaumasium (NF34a) and evaluate its larvicidal activity and biological stability. An isolate of the nematophagous fungus Monacrosporium thaumasium (NF34a) was used to produce the enzyme. The Plackett-Burman design was used in order to scan which components of the culture medium could have a significant influence on protease production by the fungus NF34a. An in vitro assay was also performed to evaluate the larvicidal activity of NF34a. It was observed that only one component of the culture medium (yeast extract), at the levels studied, had any significant effect (p < 0.05) on protease production. There was a reduction (p < 0.01) in the mean number of larvae recovered from the treated groups, compared with the control groups. The results confirm previous reports on the efficiency of nematophagous fungi for controlling nematode larvae that are potentially zoonotic. Thus, given the importance of biological control, we suggest that further studies should be conducted on the protease produced by the fungus Monacrosporium thaumasium.
Producción de conidios y clamidosporas de los hongos Duddingtonia flagrans y Monacrosporium thaumasium en diferentes medios sólidos
(Arquivos do Instituto Biológico, 2016-01) Silva, Manoel Eduardo da; Braga, Fábio Ribeiro; Borges, Luana Alcântara; Oliveira, Paulo de; Lima, Walter dos Santos; Araújo, Jackson Victor de
Las especies Duddingtonia flagrans y Monacrosporium thaumasium son micro-hongos considerados promisorios agentes del control biológico de parásitos. Bajo condiciones adversas como la falta de nutrientes, estos hongos producen esporas capaces de sobrevivieren después de pasar por el tracto gastrointestinal de los animales. La formación de estas estructuras es una característica deseable ya que promueve la sobrevivencia y la diseminación de los hongos para propósitos de biocontrol. El objetivo de este estudio fue evaluar la producción de esporas de dos especies de hongos nematófagos D. flagrans (aislados AC001 y CG722) y M. thaumasium (NF34A). Estos fueron cultivados en los subproductos agroindustriales, que tenían el intento de identificar el mejor medio para uso en programas de biocontrol de nematodos. Diferentes volúmenes (10, 15 y 20 mL) de masa micelial fueron utilizados como inóculos iniciales y adicionados a 100 gramos de medios de crecimientos sólidos (sémola de arroz - QA; sémola de maíz - QM; bagazo de caña - BC; paja de arroz - PA y cascara de café - CC) y mantenidos a 25°C en la obscuridad para evaluar la producción de esporas. Los aislados AC001 y CG722 mostraron las mejores producciones en el medio de la QA (p<0,05). El volumen de 20 mL de masa micelial utilizado como inóculo inicial proporcionó una mayor recuperación de esporas. El aislado NF34A presentó una baja o nula producción de estructuras reproductivas en los diferentes volúmenes y medios de crecimientos utilizados. La mejor producción de esporas se obtuvo utilizando subproductos de la agroindustria con mayor densidad proteica y energética.
Proteolytic activity of the nematophagous fungus Arthrobotrys sinensis on Angiostrongylus vasorum larvae
(BMC Research Notes, 2014-11-18) Soares, Filippe Elias de Freitas; Queiroz, José Humberto de; Braga, Fabio Ribeiro; Araújo, Jackson Victor de; Lima, Walter dos Santos; Zamprogno, Tatiana Tonini
The predatory nematophagous fungus Arthrobotrys sinensis (SF53) produces three proteases with nematicidal activity when grown on solid media culture. However, the proteolytic profile produced by this fungus, when grown in liquid culture medium remains unknown. Thus, the objective of this work was to evaluate the production of proteases from nematophagous fungus Arthrobotrys sinensis in liquid medium and its nematicidal activity on first stage larvae of A. vasorum. Proteases were obtained in its crude form, using Whatman no.1 filter paper, followed by centrifugation for 5 min at 10 × g and 4°C. A zymogram was performed with co-polymerized casein in an acrylamide gel as substrate. An in vitro assay to evaluate the nematicidal action of the proteases of A. sinensis (SF53) produced in liquid medium on A. vasorum L1 was conducted. By the analysis of the zymogram, it was observed a single halo at the beginning of digestion of the gel, suggesting that the three proteases of SF53 are produced in an enzymatic complex of large molecular weight. Regarding nematicidal activity, within 24 hours, the proteases produced in liquid medium of A. sinensis (SF53) showed a percentage reduction of 64% on the number of L1 of A. vasorum. In the present work, it is suggested that the three proteases of SF53 are produced in an enzymatic complex and was also demonstrated that these enzymes were effective in destroying A. vasorum L1.