<p>Destruxin concentrations in supernatant of submerged liquid cultures were determined by ... more <p>Destruxin concentrations in supernatant of submerged liquid cultures were determined by quantitative HPLC analysis of the major components, viz., DTXs A, B and E. Values are expressed in mg DTXs per g dry weight mycelium.</p
<p>* USDA-ARS Collection of Entomopathogenic Fungal Cultures, Ithaca, NY.</p><p>... more <p>* USDA-ARS Collection of Entomopathogenic Fungal Cultures, Ithaca, NY.</p><p>Identifications were provided September 2012 by curator of ARSEF* Richard Humber.</p
<p>Bioassays were performed 3 times (using two replicates for each isolate) under controlle... more <p>Bioassays were performed 3 times (using two replicates for each isolate) under controlled conditions (27°C), using new batches of larvae and conidia in each bioassay. Controls were treated with Tween 80 (0.01%) solution. Means followed by the same letter in a column do not differ statistically (<i>P</i> ≥ 0.05) (Kruskal-Wallis test followed by Student-Newman-Keuls).</p
Background Ticks are obligate bloodsucking parasites responsible for significant economic losses ... more Background Ticks are obligate bloodsucking parasites responsible for significant economic losses and concerns with human and animal health, mainly due to the transmission of pathogens. Entomopathogenic fungi have been intensively studied as an alternative strategy for tick control that can be used in combination with synthetic acaricides in the integrated management of ticks. Here, we investigated how the gut bacterial community of Rhipicephalus microplus is shaped after Metarhizium anisopliae treatment and how the tick susceptibility to the fungus is affected after disrupting gut bacterial microbiota. Methods Partially engorged tick females were artificially fed with pure bovine blood or blood plus tetracycline. Two other groups received the same diet and were topically treated with M. anisopliae. The guts were dissected, and the genomic DNA was extracted 3 days after the treatment; the V3–V4 variable region of the bacterial 16S rRNA gene was amplified. Results The gut of ticks tha...
Revista Brasileira De Parasitologia Veterinaria, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution Li... more This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Compatibility of different Metarhizium spp. propagules with synthetic acaricides for controlling Rhipicephalus microplus Compatibilidade de diferentes propágulos de Metarhizium spp. com acaricidas sintéticos para o controle de Rhipicephalus microplus
Dopamine modulates ticks and insect hemocytes and links these arthropods’ nervous and immune syst... more Dopamine modulates ticks and insect hemocytes and links these arthropods’ nervous and immune systems. For the first time, the present study analyzed the effect of a dopamine receptor antagonist on the survival, biological parameters, phagocytic index, and dopamine detection in the hemocytes of ticks challenged by Metarhizium anisopliae. The survival and egg production index of Rhipicephalus microplus were negatively impacted when ticks were inoculated with the antagonist and fungus. Five days after the treatment, the survival of ticks treated only with fungus was 2.2 times higher than ticks treated with the antagonist (highest concentration) and fungus. A reduction in the phagocytic index of hemocytes of 68.4% was observed in the group inoculated with the highest concentration of the antagonist and fungus compared to ticks treated only with fungus. No changes were detected in the R. microplus levels of intrahemocytic dopamine or hemocytic quantification. Our results support the hypo...
<p>Destruxin concentrations in supernatants of submerged liquid cultures were determined by... more <p>Destruxin concentrations in supernatants of submerged liquid cultures were determined by quantitative HPLC-UV analysis of the major components, viz., DTXs A, B and E. Values are expressed in mg DTXs per g dry weight mycelium.</p
<p>(A) Analysis of not colonized (free of fungus) plants (negative control); (B) plants end... more <p>(A) Analysis of not colonized (free of fungus) plants (negative control); (B) plants endophytically colonized by <i>Metarhizium robertsii</i> ARSEF 2575; and (C) not-colonized plants spiked with DTX standards (positive control). The cowpea seeds, both fungus-inoculated and control (not colonized) were incubated on moist filter paper under optimal light (16L∶8D) and temperature (25°C) conditions for 12 days at which time the germlings had developed roots, stems, cotyledons and two true leaves. DTXs were extracted from entire plants using methanol 100% and SPE-C18 cartridges.</p
ABSTRACT: Schistosomiasis is an important vector-borne disease transmitted by an intermediate hos... more ABSTRACT: Schistosomiasis is an important vector-borne disease transmitted by an intermediate host: a freshwater mollusk. Control of these snail vectors is one of the strategies of the World Health Organization against the disease. The present study was based on a systematic review of published scientific papers concerning the biological control of snails (genus Biomphalaria), and identified the ongoing challenges and propose future perspectives. The review methodology was based on the PRISMA statement, the international databases Web of Science and Scopus for the period 1945-2021. In total, 47 papers were analyzed, published by authors from 14 different countries, the majority being from: France, Brazil, the United States, and Egypt. The most widely used strategy for biological control was predation by fish (12 studies). Fourteen papers were published in the most prolific decade 2010-2019; during which there was also a greater diversity of biological control agents in studies. In t...
This study aimed to select Metarhizium spp. isolates to control Rhipicephalus microplus ticks by ... more This study aimed to select Metarhizium spp. isolates to control Rhipicephalus microplus ticks by analyzing their in vitro virulence against R. microplus eggs, larvae, and engorged females as well as their ability to produce aerial conidia on potato dextrose agar (PDA). After the treatment of R. microplus eggs with the highest fungal concentration (10 8 conidia.ml-1), most of the eleven tested isolates reduced the larval hatching compared to the control group, except M. anisopliae s.l. ARSEF 2211 and ARSEF 3641. M. anisopliae s.l. isolates ARSEF 729, ARSEF 760, ARSEF 929, and ARSEF 3643 exhibited the best results in the egg bioassay. In the bioassay with larvae, the entomopathogenic fungal isolates yielded average larval mortality ranging from 0.1% to 98.9% and from 23.9% to 99.9% five and fifteen days after the treatment, respectively. ARSEF 552, ARSEF 729, ARSEF 929, and ARSEF 3643 yielded the highest larval mortality. Analysis of the bioassay with R. microplus engorged females found that the different isolates negatively impacted the egg mass weight, larval hatching percent, egg production index, and nutritional index. The percent of tick control ranged from 5.32% to 70.83%, and the best tick control rates were caused by M. anisopliae s.l. ARSEF 3643 (70.83%), ARSEF 3641 (62.87%), and ARSEF 729 (64.27%). The highest conidiogenesis on PDA was observed for M. anisopliae s.l. ARSEF 3641 and M. pingshaense ARSEF 552. The isolates ARSEF 729 and ARSEF 3643 are considered promising candidates for field applications against R. microplus ticks.
ABSTRACT. de Paulo J.F., Ferreira J.R.T., Marciano A.F., de Freitas, M.C. Coutinho-Rodrigues C.J.... more ABSTRACT. de Paulo J.F., Ferreira J.R.T., Marciano A.F., de Freitas, M.C. Coutinho-Rodrigues C.J.B., Camargo M.G., Angelo I.daC. Bittencourt V.R.E.P., Golo P.S. [Association between Metarhizium anisopliae sensu lato and cypermethrin to control Rhipicephalus microplus.] Associacao de Metarhizium anisopliae sensu lato e cipermetrina para o controle de Rhipicephalus microplus. Revista Brasileira de Medicina Veterinaria, 38(supl. 3):66-74, 2016. Departamento de Parasitologia Animal, Anexo 1, Instituto de Veterinaria, Universidade Federal Rural Rio de Janeiro, BR 465 Km 47, Seropedica, RJ 23890-000, Brasil. E-mail: [email protected] Rhipicephalus microplus is responsible for large economic losses in Brazilian livestock. In order to control this arthropod, the indiscriminate use of chemical products may be widely used, leading to damages to the environment, animals and humans, besides contributing to the appearance of resistant tick populations. The use of chemicals associated with b...
In the present study, lab-on-a-chip electrophoresis (LoaC) was suggested as an alternative method... more In the present study, lab-on-a-chip electrophoresis (LoaC) was suggested as an alternative method to the conventional polyacrylamide gel electrophoresis under denaturing conditions (SDS-PAGE) to analyze raw cell-free tick hemolymph. Rhipicephalus microplus females were exposed to the entomopathogenic fungus Metarhizium anisopliae senso latu IBCB 116 strain and/or to the entomopathogenic nematode Heterorhabditis indica LPP1 strain. Hemolymph from not exposed or exposed ticks was collected 16 and 24 h after exposure and analyze by SDS-PAGE or LoaC. SDS-PAGE yielded 15 bands and LoaC electrophoresis 17 bands. Despite the differences in the number of bands, when the hemolymph protein profiles of exposed or unexposed ticks were compared in the same method, no suppressing or additional bands were detected among the treatments regardless the method (i.e., SDS-PAGE or chip electrophoresis using the Protein 230 Kit®). The potential of LoaC electrophoresis to detect protein bands from tick hemolymph was considered more efficient in comparison to the detection obtained using the traditional SDS-PAGE method, especially when it comes to protein subunits heavier than 100 KDa. LoaC electrophoresis provided a very good reproducibility, and is much faster than the conventional SDS-PAGE method, which requires several hours for one analysis. Despite both methods can be used to analyze tick hemolymph composition, LoaC was considered more suitable for cell-free hemolymph protein separation and detection. LoaC hemolymph band percent data reported changes in key proteins (i.e., HeLp and vitellogenin) exceptionally important for tick embryogenesis. This study reported, for the first time, tick hemolymph protein profile using LoaC.
Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long b... more Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long been assumed to contribute to virulence of these entomopathogenic fungi. We evaluated the virulence of 20 Metarhizium isolates against insect larvae and measured the concentration of DTXs A, B, and E produced by these same isolates in submerged (shaken) cultures. Eight of the isolates (ARSEF 324, 724, 760, 1448, 1882, 1883, 3479, and 3918) did not produce DTXs A, B, or E during the five days of submerged culture. DTXs were first detected in culture medium at 2-3 days in submerged culture. Galleria mellonella and Tenebrio molitor showed considerable variation in their susceptibility to the Metarhizium isolates. The concentration of DTXs produced in vitro did not correlate with percent or speed of insect kill. We established endophytic associations of M. robertsii and M. acridum isolates in Vigna unguiculata (cowpeas) and Cucumis sativus (cucumber) plants. DTXs were detected in cowpeas colonized by M. robertsii ARSEF 2575 12 days after fungal inoculation, but DTXs were not detected in cucumber. This is the first instance of DTXs detected in plants endophytically colonized by M. robertsii. This finding has implications for new approaches to fungus-based biological control of pest arthropods.
Rhipicephalus microplus (Canestrini) is an ectoparasite accountable for great economic losses. Th... more Rhipicephalus microplus (Canestrini) is an ectoparasite accountable for great economic losses. The use of entomopathogenic fungi to control arthropods has shown promising responses. The present study evaluated the virulence of Isaria farinosa (Holmsk.) Fr., Isaria fumosorosea (Wize) Brown and Smith, and Purpureocillium lilacinum (=Paecilomyces lilacinus) (Thom.) Samson to engorged females, eggs, and larvae of R. microplus. There were four treatment groups (10(5), 10(6), 10(7), and 10(8) conidia ml(-1)) and the control group (water and Tween 80, 0.1% v/v). The treatment was based on immersion of the specimen in 1 ml of the suspension or control solution. The study observed changes in egg viability and larval mortality after treatment. The results showed that I. farinosa, P. lilacinum, and I. fumosorosea caused alterations in the biological parameters of R. microplus ticks. I. fumosorosea presented the greatest potential to control R. microplus engorged females in vitro, causing a 49% decrease in nutritional index. All fungal isolates presented significant reduction in the egg production index. I. farinosa reduced the hatching percentage if the eggs were treated with the two highest conidial concentrations. All conidial concentrations of I. fumosorosea were able to reduce the hatching percentage significantly. All tested isolates showed pathogenicity toward unfed R. microplus larvae. As far as we know, this is the first study reporting the effect in vitro of I. farinosa, I. fumosorosea, and P. lilacinum to different developmental stages of R. microplus ticks.
ABSTRACT. Marciano A.F., Coutinho-Rodrigues C.J.B., Perinotto W.M.S., Camargo M.G., Golo P.S., Sa... more ABSTRACT. Marciano A.F., Coutinho-Rodrigues C.J.B., Perinotto W.M.S., Camargo M.G., Golo P.S., Sa F.A., Quinelato S., Freitas M.C., Angelo I.C., Nogueira M.R.S. & Bittencourt V.R.E.P. [Metarhizium anisopliae: influence of pH on enzyme activity and control of Rhipicephalus microplus ticks.] Metarhizium anisopliae: influencia do pH na atividade enzimatica e no controle de Rhipicephalus microplus. Revista Brasileira de Medicina Veterinaria, 37(Supl.1):85-90, 2015. Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, BR 465, Km 47, Seropedica, RJ 23897-970, Brasil. E-mail: [email protected] Rhipicephalus microplus ticks are one of the major agents causing substantial losses to livestock worldwide. In the search for alternative control strategies, both in vitro and in vivo use of the arthropodpathogenic fungus Metarhizium anisopliae has shown promising results against this ectoparasite. During host colonization, protease production by M. anisopliae is consi...
The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in econ... more The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in economic losses aggravated by tick resistance to chemical acaricides. Strains of Metarhizium spp., a well-known group of entomopathogenic fungi, can contribute to managing this ectoparasite. We explored two novel granular, microsclerotia- or blastospores-based formulations of Metarhizium robertsii for R. microplus control under semi-field conditions. Fungal persistence in soil was also observed for 336 days. The experiment used pots of Urochloa decumbens cv. Basilisk grass, treated with 0.25 or 0.5 mg of granular formulation/cm2 (25 or 50 kg/ha) applied to the soil surface prior to transferring engorged tick females onto the treated soil. The fungal granules yielded more conidia with subsequent sporulation under controlled indoor conditions than in the outdoor environment, where the levels of fungus rapidly declined over time. Metarhizium-root colonization ranged from 25 to 66.7% depending o...
Dopamine (DA) is a biogenic monoamine reported to modulate insect hemocytes. Although the immune ... more Dopamine (DA) is a biogenic monoamine reported to modulate insect hemocytes. Although the immune functions of DA are known in insects, there is a lack of knowledge of DA’s role in the immune system of ticks. The use of Metarhizium anisopliae has been considered for tick control, driving studies on the immune response of these arthropods challenged with fungi. The present study evaluated the effect of DA on the cellular immune response and survival of Rhipicephalus microplus inoculated with M. anisopliae blastospores. Exogenous DA increased both ticks’ survival 72 h after M. anisopliae inoculation and the number of circulating hemocytes compared to the control group, 24 h after the treatment. The phagocytic index of tick hemocytes challenged with M. anisopliae did not change upon injection of exogenous DA. Phenoloxidase activity in the hemolymph of ticks injected with DA and the fungus or exclusively with DA was higher than in untreated ticks or ticks inoculated with the fungus alone...
<p>Destruxin concentrations in supernatant of submerged liquid cultures were determined by ... more <p>Destruxin concentrations in supernatant of submerged liquid cultures were determined by quantitative HPLC analysis of the major components, viz., DTXs A, B and E. Values are expressed in mg DTXs per g dry weight mycelium.</p
<p>* USDA-ARS Collection of Entomopathogenic Fungal Cultures, Ithaca, NY.</p><p>... more <p>* USDA-ARS Collection of Entomopathogenic Fungal Cultures, Ithaca, NY.</p><p>Identifications were provided September 2012 by curator of ARSEF* Richard Humber.</p
<p>Bioassays were performed 3 times (using two replicates for each isolate) under controlle... more <p>Bioassays were performed 3 times (using two replicates for each isolate) under controlled conditions (27°C), using new batches of larvae and conidia in each bioassay. Controls were treated with Tween 80 (0.01%) solution. Means followed by the same letter in a column do not differ statistically (<i>P</i> ≥ 0.05) (Kruskal-Wallis test followed by Student-Newman-Keuls).</p
Background Ticks are obligate bloodsucking parasites responsible for significant economic losses ... more Background Ticks are obligate bloodsucking parasites responsible for significant economic losses and concerns with human and animal health, mainly due to the transmission of pathogens. Entomopathogenic fungi have been intensively studied as an alternative strategy for tick control that can be used in combination with synthetic acaricides in the integrated management of ticks. Here, we investigated how the gut bacterial community of Rhipicephalus microplus is shaped after Metarhizium anisopliae treatment and how the tick susceptibility to the fungus is affected after disrupting gut bacterial microbiota. Methods Partially engorged tick females were artificially fed with pure bovine blood or blood plus tetracycline. Two other groups received the same diet and were topically treated with M. anisopliae. The guts were dissected, and the genomic DNA was extracted 3 days after the treatment; the V3–V4 variable region of the bacterial 16S rRNA gene was amplified. Results The gut of ticks tha...
Revista Brasileira De Parasitologia Veterinaria, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution Li... more This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Compatibility of different Metarhizium spp. propagules with synthetic acaricides for controlling Rhipicephalus microplus Compatibilidade de diferentes propágulos de Metarhizium spp. com acaricidas sintéticos para o controle de Rhipicephalus microplus
Dopamine modulates ticks and insect hemocytes and links these arthropods’ nervous and immune syst... more Dopamine modulates ticks and insect hemocytes and links these arthropods’ nervous and immune systems. For the first time, the present study analyzed the effect of a dopamine receptor antagonist on the survival, biological parameters, phagocytic index, and dopamine detection in the hemocytes of ticks challenged by Metarhizium anisopliae. The survival and egg production index of Rhipicephalus microplus were negatively impacted when ticks were inoculated with the antagonist and fungus. Five days after the treatment, the survival of ticks treated only with fungus was 2.2 times higher than ticks treated with the antagonist (highest concentration) and fungus. A reduction in the phagocytic index of hemocytes of 68.4% was observed in the group inoculated with the highest concentration of the antagonist and fungus compared to ticks treated only with fungus. No changes were detected in the R. microplus levels of intrahemocytic dopamine or hemocytic quantification. Our results support the hypo...
<p>Destruxin concentrations in supernatants of submerged liquid cultures were determined by... more <p>Destruxin concentrations in supernatants of submerged liquid cultures were determined by quantitative HPLC-UV analysis of the major components, viz., DTXs A, B and E. Values are expressed in mg DTXs per g dry weight mycelium.</p
<p>(A) Analysis of not colonized (free of fungus) plants (negative control); (B) plants end... more <p>(A) Analysis of not colonized (free of fungus) plants (negative control); (B) plants endophytically colonized by <i>Metarhizium robertsii</i> ARSEF 2575; and (C) not-colonized plants spiked with DTX standards (positive control). The cowpea seeds, both fungus-inoculated and control (not colonized) were incubated on moist filter paper under optimal light (16L∶8D) and temperature (25°C) conditions for 12 days at which time the germlings had developed roots, stems, cotyledons and two true leaves. DTXs were extracted from entire plants using methanol 100% and SPE-C18 cartridges.</p
ABSTRACT: Schistosomiasis is an important vector-borne disease transmitted by an intermediate hos... more ABSTRACT: Schistosomiasis is an important vector-borne disease transmitted by an intermediate host: a freshwater mollusk. Control of these snail vectors is one of the strategies of the World Health Organization against the disease. The present study was based on a systematic review of published scientific papers concerning the biological control of snails (genus Biomphalaria), and identified the ongoing challenges and propose future perspectives. The review methodology was based on the PRISMA statement, the international databases Web of Science and Scopus for the period 1945-2021. In total, 47 papers were analyzed, published by authors from 14 different countries, the majority being from: France, Brazil, the United States, and Egypt. The most widely used strategy for biological control was predation by fish (12 studies). Fourteen papers were published in the most prolific decade 2010-2019; during which there was also a greater diversity of biological control agents in studies. In t...
This study aimed to select Metarhizium spp. isolates to control Rhipicephalus microplus ticks by ... more This study aimed to select Metarhizium spp. isolates to control Rhipicephalus microplus ticks by analyzing their in vitro virulence against R. microplus eggs, larvae, and engorged females as well as their ability to produce aerial conidia on potato dextrose agar (PDA). After the treatment of R. microplus eggs with the highest fungal concentration (10 8 conidia.ml-1), most of the eleven tested isolates reduced the larval hatching compared to the control group, except M. anisopliae s.l. ARSEF 2211 and ARSEF 3641. M. anisopliae s.l. isolates ARSEF 729, ARSEF 760, ARSEF 929, and ARSEF 3643 exhibited the best results in the egg bioassay. In the bioassay with larvae, the entomopathogenic fungal isolates yielded average larval mortality ranging from 0.1% to 98.9% and from 23.9% to 99.9% five and fifteen days after the treatment, respectively. ARSEF 552, ARSEF 729, ARSEF 929, and ARSEF 3643 yielded the highest larval mortality. Analysis of the bioassay with R. microplus engorged females found that the different isolates negatively impacted the egg mass weight, larval hatching percent, egg production index, and nutritional index. The percent of tick control ranged from 5.32% to 70.83%, and the best tick control rates were caused by M. anisopliae s.l. ARSEF 3643 (70.83%), ARSEF 3641 (62.87%), and ARSEF 729 (64.27%). The highest conidiogenesis on PDA was observed for M. anisopliae s.l. ARSEF 3641 and M. pingshaense ARSEF 552. The isolates ARSEF 729 and ARSEF 3643 are considered promising candidates for field applications against R. microplus ticks.
ABSTRACT. de Paulo J.F., Ferreira J.R.T., Marciano A.F., de Freitas, M.C. Coutinho-Rodrigues C.J.... more ABSTRACT. de Paulo J.F., Ferreira J.R.T., Marciano A.F., de Freitas, M.C. Coutinho-Rodrigues C.J.B., Camargo M.G., Angelo I.daC. Bittencourt V.R.E.P., Golo P.S. [Association between Metarhizium anisopliae sensu lato and cypermethrin to control Rhipicephalus microplus.] Associacao de Metarhizium anisopliae sensu lato e cipermetrina para o controle de Rhipicephalus microplus. Revista Brasileira de Medicina Veterinaria, 38(supl. 3):66-74, 2016. Departamento de Parasitologia Animal, Anexo 1, Instituto de Veterinaria, Universidade Federal Rural Rio de Janeiro, BR 465 Km 47, Seropedica, RJ 23890-000, Brasil. E-mail: [email protected] Rhipicephalus microplus is responsible for large economic losses in Brazilian livestock. In order to control this arthropod, the indiscriminate use of chemical products may be widely used, leading to damages to the environment, animals and humans, besides contributing to the appearance of resistant tick populations. The use of chemicals associated with b...
In the present study, lab-on-a-chip electrophoresis (LoaC) was suggested as an alternative method... more In the present study, lab-on-a-chip electrophoresis (LoaC) was suggested as an alternative method to the conventional polyacrylamide gel electrophoresis under denaturing conditions (SDS-PAGE) to analyze raw cell-free tick hemolymph. Rhipicephalus microplus females were exposed to the entomopathogenic fungus Metarhizium anisopliae senso latu IBCB 116 strain and/or to the entomopathogenic nematode Heterorhabditis indica LPP1 strain. Hemolymph from not exposed or exposed ticks was collected 16 and 24 h after exposure and analyze by SDS-PAGE or LoaC. SDS-PAGE yielded 15 bands and LoaC electrophoresis 17 bands. Despite the differences in the number of bands, when the hemolymph protein profiles of exposed or unexposed ticks were compared in the same method, no suppressing or additional bands were detected among the treatments regardless the method (i.e., SDS-PAGE or chip electrophoresis using the Protein 230 Kit®). The potential of LoaC electrophoresis to detect protein bands from tick hemolymph was considered more efficient in comparison to the detection obtained using the traditional SDS-PAGE method, especially when it comes to protein subunits heavier than 100 KDa. LoaC electrophoresis provided a very good reproducibility, and is much faster than the conventional SDS-PAGE method, which requires several hours for one analysis. Despite both methods can be used to analyze tick hemolymph composition, LoaC was considered more suitable for cell-free hemolymph protein separation and detection. LoaC hemolymph band percent data reported changes in key proteins (i.e., HeLp and vitellogenin) exceptionally important for tick embryogenesis. This study reported, for the first time, tick hemolymph protein profile using LoaC.
Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long b... more Destruxins (DTXs) are cyclic depsipeptides produced by many Metarhizium isolates that have long been assumed to contribute to virulence of these entomopathogenic fungi. We evaluated the virulence of 20 Metarhizium isolates against insect larvae and measured the concentration of DTXs A, B, and E produced by these same isolates in submerged (shaken) cultures. Eight of the isolates (ARSEF 324, 724, 760, 1448, 1882, 1883, 3479, and 3918) did not produce DTXs A, B, or E during the five days of submerged culture. DTXs were first detected in culture medium at 2-3 days in submerged culture. Galleria mellonella and Tenebrio molitor showed considerable variation in their susceptibility to the Metarhizium isolates. The concentration of DTXs produced in vitro did not correlate with percent or speed of insect kill. We established endophytic associations of M. robertsii and M. acridum isolates in Vigna unguiculata (cowpeas) and Cucumis sativus (cucumber) plants. DTXs were detected in cowpeas colonized by M. robertsii ARSEF 2575 12 days after fungal inoculation, but DTXs were not detected in cucumber. This is the first instance of DTXs detected in plants endophytically colonized by M. robertsii. This finding has implications for new approaches to fungus-based biological control of pest arthropods.
Rhipicephalus microplus (Canestrini) is an ectoparasite accountable for great economic losses. Th... more Rhipicephalus microplus (Canestrini) is an ectoparasite accountable for great economic losses. The use of entomopathogenic fungi to control arthropods has shown promising responses. The present study evaluated the virulence of Isaria farinosa (Holmsk.) Fr., Isaria fumosorosea (Wize) Brown and Smith, and Purpureocillium lilacinum (=Paecilomyces lilacinus) (Thom.) Samson to engorged females, eggs, and larvae of R. microplus. There were four treatment groups (10(5), 10(6), 10(7), and 10(8) conidia ml(-1)) and the control group (water and Tween 80, 0.1% v/v). The treatment was based on immersion of the specimen in 1 ml of the suspension or control solution. The study observed changes in egg viability and larval mortality after treatment. The results showed that I. farinosa, P. lilacinum, and I. fumosorosea caused alterations in the biological parameters of R. microplus ticks. I. fumosorosea presented the greatest potential to control R. microplus engorged females in vitro, causing a 49% decrease in nutritional index. All fungal isolates presented significant reduction in the egg production index. I. farinosa reduced the hatching percentage if the eggs were treated with the two highest conidial concentrations. All conidial concentrations of I. fumosorosea were able to reduce the hatching percentage significantly. All tested isolates showed pathogenicity toward unfed R. microplus larvae. As far as we know, this is the first study reporting the effect in vitro of I. farinosa, I. fumosorosea, and P. lilacinum to different developmental stages of R. microplus ticks.
ABSTRACT. Marciano A.F., Coutinho-Rodrigues C.J.B., Perinotto W.M.S., Camargo M.G., Golo P.S., Sa... more ABSTRACT. Marciano A.F., Coutinho-Rodrigues C.J.B., Perinotto W.M.S., Camargo M.G., Golo P.S., Sa F.A., Quinelato S., Freitas M.C., Angelo I.C., Nogueira M.R.S. & Bittencourt V.R.E.P. [Metarhizium anisopliae: influence of pH on enzyme activity and control of Rhipicephalus microplus ticks.] Metarhizium anisopliae: influencia do pH na atividade enzimatica e no controle de Rhipicephalus microplus. Revista Brasileira de Medicina Veterinaria, 37(Supl.1):85-90, 2015. Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, BR 465, Km 47, Seropedica, RJ 23897-970, Brasil. E-mail: [email protected] Rhipicephalus microplus ticks are one of the major agents causing substantial losses to livestock worldwide. In the search for alternative control strategies, both in vitro and in vivo use of the arthropodpathogenic fungus Metarhizium anisopliae has shown promising results against this ectoparasite. During host colonization, protease production by M. anisopliae is consi...
The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in econ... more The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in economic losses aggravated by tick resistance to chemical acaricides. Strains of Metarhizium spp., a well-known group of entomopathogenic fungi, can contribute to managing this ectoparasite. We explored two novel granular, microsclerotia- or blastospores-based formulations of Metarhizium robertsii for R. microplus control under semi-field conditions. Fungal persistence in soil was also observed for 336 days. The experiment used pots of Urochloa decumbens cv. Basilisk grass, treated with 0.25 or 0.5 mg of granular formulation/cm2 (25 or 50 kg/ha) applied to the soil surface prior to transferring engorged tick females onto the treated soil. The fungal granules yielded more conidia with subsequent sporulation under controlled indoor conditions than in the outdoor environment, where the levels of fungus rapidly declined over time. Metarhizium-root colonization ranged from 25 to 66.7% depending o...
Dopamine (DA) is a biogenic monoamine reported to modulate insect hemocytes. Although the immune ... more Dopamine (DA) is a biogenic monoamine reported to modulate insect hemocytes. Although the immune functions of DA are known in insects, there is a lack of knowledge of DA’s role in the immune system of ticks. The use of Metarhizium anisopliae has been considered for tick control, driving studies on the immune response of these arthropods challenged with fungi. The present study evaluated the effect of DA on the cellular immune response and survival of Rhipicephalus microplus inoculated with M. anisopliae blastospores. Exogenous DA increased both ticks’ survival 72 h after M. anisopliae inoculation and the number of circulating hemocytes compared to the control group, 24 h after the treatment. The phagocytic index of tick hemocytes challenged with M. anisopliae did not change upon injection of exogenous DA. Phenoloxidase activity in the hemolymph of ticks injected with DA and the fungus or exclusively with DA was higher than in untreated ticks or ticks inoculated with the fungus alone...
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