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1.
World J Microbiol Biotechnol ; 35(8): 128, 2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31375920

RESUMO

Large patch disease, caused by Rhizoctonia solani AG2-2, is the most devastating disease in Zoysiagrass (Zoysia japonica). Current large patch disease control strategies rely primarily upon the use of chemical pesticides. Streptomyces sp. S8 is known to possess exceptional antagonistic properties that could potentially suppress the large patch pathogen found at turfgrass plantations. This study aims to demonstrate the feasibility of using the strain as a biological control mechanism. Sequencing of the S8 strain genome revealed a valinomycin biosynthesis gene cluster. This cluster is composed of the vlm1 and vlm2 genes, which are known to produce antifungal compounds. In order to verify this finding for the large patch pathogen, a valinomycin biosynthesis knockout mutant was created via the CRISPR/Cas9 system. The mutant lost antifungal activity against the large patch pathogen. Consequently, it is anticipated that eco-friendly microbial preparations derived from the S8 strain can be utilized to biologically control large patch disease.


Assuntos
Antifúngicos/metabolismo , Antifúngicos/farmacologia , Rhizoctonia/efeitos dos fármacos , Streptomyces/metabolismo , Valinomicina/metabolismo , Valinomicina/farmacologia , Vias Biossintéticas/genética , Técnicas de Inativação de Genes , Genoma Bacteriano , Família Multigênica , Controle Biológico de Vetores/métodos , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Poaceae/microbiologia , Rhizoctonia/crescimento & desenvolvimento , Análise de Sequência de DNA , Streptomyces/genética
2.
Rev Soc Bras Med Trop ; 52: e20190135, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31390442

RESUMO

INTRODUCTION: Musca domestica is resistant to many insecticides; hence, biological control is a suitable alternative. METHODS: We evaluated the lethality of strain Btk176 towards the larval and adult M. domestica and the histopathological effects in the larvae midgut. RESULTS: We observed 99% larval and 78.9% adult mortality within 48 hours of spore ingestion (dosage, 2.4×108 CFU/ml). The histopathological effects were consistent with cytotoxicity. PCR analysis showed the presence of the cry1Ba gene. Transmission electron microscopy revealed a bipyramidal parasporal body. Thurigiensin activity was not detected. CONCLUSIONS: The serovar, Btk176 might be a potential biocontrol agent for houseflies.


Assuntos
Bacillus thuringiensis , Toxinas Bacterianas/farmacologia , Moscas Domésticas/efeitos dos fármacos , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Análise de Variância , Animais , Contagem de Colônia Microbiana , Exotoxinas , Microscopia Eletrônica de Transmissão , Controle Biológico de Vetores/métodos , Reprodutibilidade dos Testes
3.
Ying Yong Sheng Tai Xue Bao ; 30(7): 2511-2520, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31418254

RESUMO

It's well known that regional agricultural landscape pattern can significantly regulate the relationship between plants, herbivorous insects and natural enemies. The improvement of the ecosystem services of regional agricultural landscape pattern has profound impacts on pest control, which has received much interests in current landscape ecology and pest control studies. This review systematically summarized the impacts of agricultural landscape pattern, as well as its succession on the diversity and ecological pests control of important natural enemies. From the perspective of different natural enemies, the impacts of agricultural landscape pattern on natural predators, parasi-toids, beneficial microorganisms and its ecological pests control functions were all recapped. We outlined crop spatial distribution and vegetation habitat management strategies. This review could provide useful insights in improving the ecosystem services of natural enemies in agricultural landscape based on the vegetation habitat management, and offer theoretical support for regional ecological agriculture in response to the strategy of 'chemical pesticide reduction application'.


Assuntos
Agricultura , Controle Biológico de Vetores , Animais , Ecologia , Ecossistema , Insetos
4.
An Acad Bras Cienc ; 91(3): e20180326, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432898

RESUMO

The sugarcane borer, Diatraea saccharalis is one of the hosts more used for parasitoid pupal multiplication in Brazil. The parasitoids pupal of Trichospilus diatraeae and Palmistichus elaeisis are generalist natural enemies with potential to suppress populations of diverse families of lepidopteran pests. The success in the utilization of these natural enemies in the field is directly related to the capacity of search of the host, this capacity might be affected by the presence of the pathogens. In this context, the aim of this essay was to detect the presence of intracellular parasites of Phylum Microsporidia. These pathogens may cause morphological and behavioral alterations. The presence of infection was verified by microscopy and was confirmed by amplification of region small subunit (SSU) of ribosomal RNA using universal primers for microsporidia of Nosema sp. The purified PCR products were submitted to sequencing, and the sequences that had been obtained were edited and aligned with the sequences in a Genbank database. In this way, it was possible to verify the presence of intracellular parasites in T. diatraeae, P. elaeisis and D. saccharalis pertaining to Clade Nosema/Vairimorpha. However, this is the first one report about detection of the microsporidia in the parasitoids T. diatraeae and P. elaeisis.


Assuntos
Interações Hospedeiro-Parasita/fisiologia , Mariposas/parasitologia , Nosema/fisiologia , Controle Biológico de Vetores/métodos , Pupa/parasitologia , Animais
5.
Sheng Wu Gong Cheng Xue Bao ; 35(8): 1511-1519, 2019 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-31441622

RESUMO

With the rapid development of transgenic technology, the safety of genetically modified products has received extensive attention. Certified reference materials for the detection of genetically modified organisms play important roles in ensuring comparability and traceability of the qualitative and quantitative detection of genetically modified products. However, the development of protein reference materials is relatively slow, and one of the difficulties is the preparation of protein candidates with high purity. The cry1Ah1 gene of Bacillus thuringiensis has been used for the development of transgenic insect-resistant crops because of its excellent insecticidal activity against lepidopteran pests such as Asian corn borer, and has obtained transgenic lines with good insect resistance traits. In order to develop Cry1Ah protein certified reference material, it is urgent to establish a preparation and purification system. In this study, a system for preparing Cry1Ah protein by Bt expression system was optimized, and a high-purity Cry1Ah protein (size exclusion chromatography purity: 99.6%) was obtained by ion-exchange chromatography and size exclusion chromatography stepwise purification. The results of biological activity assay showed that there was no significant difference in the insecticidal activity of purified Cry1Ah protein and protoxin against diamondback moths (Plutella xylostella). Finally, the amino acid sequence of the activated Cry1Ah protein was determined using Edman degradation and mass spectrometry. In summary, the obtained Cry1Ah pure protein can be used for the development of protein reference materials.


Assuntos
Criptocromos/metabolismo , Animais , Bacillus thuringiensis , Proteínas de Bactérias , Endotoxinas , Proteínas Hemolisinas , Mariposas , Controle Biológico de Vetores , Plantas Geneticamente Modificadas
6.
Vet Parasitol ; 272: 64-74, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31395207

RESUMO

This study aimed to evaluate the mite fauna and their ecological interactions in commercial laying hen farms in the state of Rio Grande do Sul, Brazil. It was conducted from August 2013 through August 2014 with two sampling strategies (feathers and traps) in three different production systems: automated (A1,2,3), semi-automated (S1,2) and free-range (FR). A total of 38,383 mites were collected belonging to 23 families and 33 species, most of which were collected in feathers (74%) followed by traps (26%). There was higher abundance at S1 (10,774-28.1%) and S2 (11,023-28.7%) followed by FR (6972-18.2%), A1 (1896-4.9%), A2 (4775-12.4%), and A3 (2943-7.7%). Higher richness was observed at S1 (23 species), S2 (18 species), and FR (19 species). Megninia ginglymura (Mégnin) (Analgidae) was the species with the highest health importance, eudominant on feathers, and its populations seems to be related with increased temperature. Tuccioglyphus setosus Horn et al. (Pyroglyphidae) seems to be influenced by relative air humidity and temperature. Predators with the highest populations were Cheyletus malaccensis (Oudemans) (Cheyletidae), Typhlodromus transvaalensis (Nesbitt) (Phytoseiidae), Blattisocius keegani (Fox), and Blattisocius dentriticus (Berlese) (Blattisocidae).


Assuntos
Infestações por Ácaros/veterinária , Ácaros/fisiologia , Doenças das Aves Domésticas/parasitologia , Criação de Animais Domésticos , Animais , Biodiversidade , Brasil , Galinhas , Feminino , Temperatura Alta , Umidade , Infestações por Ácaros/parasitologia , Ácaros/classificação , Controle Biológico de Vetores , Dinâmica Populacional , Fatores de Risco
7.
Pestic Biochem Physiol ; 158: 166-174, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378353

RESUMO

Pesticidal properties of Bacillus thuringiensis and its associated toxic proteins is an ever-growing science with potential implications in biological pest management. In the present study 80 Bacillus thuringiensis isolates native to Uttarakhand Himalayas were evaluated for chitinolytic activity and potent ones (11 isolates) were further subjected to multiphasic characterization for their antifungal, insecticidal and synergistic properties with selected chemical insecticides. Although all the 11 potent isolates were biologically active, only three isolates (VLBt27, VLBt109 and VLBt238) showed >90% inhibition in radial growth of 3 out of 4 tested plant pathogenic fungi (Rhizoctonia solani, Fusarium oxysporum, Alternaria pori and Pyricularia oryzae). The key antagonism was manifested in the form of disruptions in growing tips and uneven mycelial thickenings. In insect bioassays (against Helicoverpa armigera, Mythimna separata and Thysanoplusia orichalcea), no considerable direct mortality was observed. However, the larval weight reduction was prominent in four isolates (VLBt27, VLBt38, VLBt109 and VLBt135) which accounts to >75% in first instar larvae of H. armigera. Joint action of these four isolates with chemical insecticides showed an overall additive interaction against Brevicoryne brassicae and synergism against H. armigera. All the isolates were compatible with tested insecticides at their field recommended doses except for chlorpyriphos with around 130 kDa protein as chitinase. The study identified VLBt27 and VLBt109, two native isolates of B. thuringiensis with potential antagonistic activity and synergism as well. These isolates have possible implications as single strategy against two diverse pest problems (pathogenic fungi and phytophagous insect) of agriculture with a view of reduced pesticide application.


Assuntos
Bacillus thuringiensis/fisiologia , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Animais , Quitinases/metabolismo , Controle Biológico de Vetores
8.
Pestic Biochem Physiol ; 158: 54-60, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31378361

RESUMO

Extensive planting of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has spurred increasingly rapid evolution of resistance in pests. In the pink bollworm, Pectinophora gossypiella, a devastating global pest, resistance to Bt toxin Cry1Ac produced by transgenic cotton is linked with mutations in a gene (PgCad1) encoding a cadherin protein that binds Cry1Ac in the larval midgut. We previously reported a long non-coding RNA (lncRNA) in intron 20 of cadherin alleles associated with both resistance and susceptibility to Cry1Ac. Here we tested the hypothesis that reducing expression of this lncRNA decreases transcription of PgCad1 and susceptibility to Cry1Ac. Quantitative RT-PCR showed that feeding susceptible neonates small interfering RNAs (siRNAs) targeting this lncRNA but not PgCad1 decreased the abundance of transcripts of both the lncRNA and PgCad1. Moreover, neonates fed the siRNAs had lower susceptibility to Cry1Ac. The results imply that the lncRNA increases transcription of PgCad1 and susceptibility of pink bollworm to Cry1Ac. The results suggest that disruption of lncRNA expression could be a novel mechanism of pest resistance to Bt toxins.


Assuntos
Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/farmacologia , Caderinas/genética , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Mariposas/efeitos dos fármacos , RNA Longo não Codificante/genética , Transcrição Genética/genética , Animais , Bacillus thuringiensis/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Mariposas/genética , Mariposas/metabolismo , Controle Biológico de Vetores
9.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2129-2136, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257788

RESUMO

Endoparasitic fungi are a group of nematophagous fungi which produce a variety of special spores to infect free nematodes. They play a key role in maintaining the population density of nematodes in the natural systems. Moreover, they are important materials for the study of species diversity. Therefore, they have special research significance and economic values. At present, many studies mainly focus on the infectivity of trapping fungi to nematodes, and mainly directed at the second instars larvae. However, the endoparasitic fungi have infectivity to nematodes at all stages. Here, we reviewed the resource status, diversity of spore morphology, infection modes, life history and host of endoparasitic fungi, and the biocontrol fungi with development potential and their commercialized application. Finally, we proposed some suggestions for future researches.


Assuntos
Fungos , Nematoides , Controle Biológico de Vetores , Animais , Larva
10.
Exp Parasitol ; 204: 107729, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31348914

RESUMO

The objectives of this study are to: (1) evaluate the in vitro acaricidal effect of 54 Metarhizium anisopliae strains, six Beauveria bassiana strains and one Purpureocilium lilacinum strain, against the larvae of two populations of Rhipicephalus microplus (multi-resistant and susceptible to chemical acaricides); and (2) determine the lethal concentrations required to eliminate the 50% (LC50) and 99% (LC99) of larvae through the use of entomopathogenic fungi (EF) with high acaricidal effects. The mortality percentage was evaluated by larval immersion tests at a dose of 1 × 108 conidia/mL for each fungal strain. For calculating LC50 and LC99, four doses (1 × 108, 1 × 107, 1 × 106 and 1 × 105) were used. Nine strains of M. anisopliae and the P. lilacinum strain showed a high mortality percentage in the R. microplus larvae of both populations. The best strains that showed the lowest values of LC50 and LC99 for tick elimination were MaV50 and PlV01. In conclusion, several strains of entomopathogenic fungi showed a high acaricidal effect against the R. microplus larvae of both populations, suggesting that these fungi might be a promissory adjuvant in the control of R. microplus, including those who are resistant. Finally, the discovery of a P. lilacinum strain with a high acaricidal effect is also reported.


Assuntos
Acaricidas/farmacologia , Fungos/patogenicidade , Controle Biológico de Vetores/métodos , Rhipicephalus/microbiologia , Microbiologia do Solo , Animais , Beauveria/patogenicidade , Bioensaio/veterinária , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Feminino , Hypocreales/patogenicidade , Resistência a Inseticidas , Larva/efeitos dos fármacos , Larva/microbiologia , Dose Letal Mediana , Masculino , Metarhizium/patogenicidade , México , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/tratamento farmacológico , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária , Virulência
11.
Microbiol Res ; 226: 41-47, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284943

RESUMO

Myzus persicae Sulzer (Hemiptera: Aphididae), is a generalist cosmopolitan insect that infests more than 400 plant species of 40 different families and is one of the major pests infesting potato crops. It causes direct damage and also spread plant viruses. The intensive use of synthetic insecticide to control aphids has led to resistant populations. Therefore, there is a need to develop biopesticides for effective control that minimizes environmental hazards. The bacteria Bacillus amyloliquefaciens is recognized as a producer of a variety of bioactive compounds. The aim here was to evaluate the aphicidal effect of B. amyloliquefaciens strains, CBMDDrag3, PGPBacCA2, and CBMDLO3, and their metabolites on the mortality and fecundity of M. persicae. Cells suspensions, heat-killed cell suspensions, cell-free supernatants, or isolated lipopeptide fractions from B. amyloliquefaciens strains were offered to aphids through artificial diets. The isolated lipopeptide fractions composed mainly of kurstakins, surfactins, iturins, and fengycins, when were administrated through diets, had no aphicidal effect against M. persicae. However, aphids fed on diets with whole cell suspensions and its cell-free supernatant of all three bacteria strains resulted in 100% mortality of adult aphids and nymphs. Specially, B. amyloliquefaciens CBMDLO3, has an effective aphicidal effect on M. persicae, used both bacterial cells and their metabolites. Moreover, heat-killed cells of B. amyloliquefaciens CBMDLO3 also had aphicidal action, although the aphid mortality was lower than on diet with living bacteria. Therefore, these results propose that B. amyloliquefaciens, could function as a novel eco-friendly biopesticide for the control of M. persicae.


Assuntos
Afídeos/efeitos dos fármacos , Afídeos/microbiologia , Bacillus amyloliquefaciens/metabolismo , Controle Biológico de Vetores , Animais , Bacillus amyloliquefaciens/isolamento & purificação , Agentes de Controle Biológico/isolamento & purificação , Agentes de Controle Biológico/metabolismo , Agentes de Controle Biológico/farmacologia , Feminino , Controle de Insetos/métodos , Inseticidas/isolamento & purificação , Inseticidas/metabolismo , Inseticidas/farmacologia , Lipopeptídeos/isolamento & purificação , Lipopeptídeos/metabolismo , Lipopeptídeos/farmacologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle
12.
Washington, D. C.; OPS; 2019-07-21.
em Espanhol | PAHO-IRIS | ID: phr-51376

RESUMO

[Introducción]. La historia del control de las enfermedades transmitidas por vectores en las Américas es muy extensa y las evidencias muestran lo exitosos que fueron varios programas en el pasado. El control de la fiebre amarilla y el paludismo en Cuba y Panamá bajo la dirección de William Gorgas (1901-1910), la eliminación de Anopheles gambiae en el Brasil (1940), la eliminación de Aedes aegypti entre 1950 y 1960 auspiciada por la OPS y dirigida por Fred Soper, la eliminación de la transmisión de la enfermedad de Chagas por Triatoma infestans en el Brasil y el Uruguay y la reciente eliminación de la oncocercosis de 11 de los 13 focos endémicos en Colombia, Ecuador, México y Guatemala (2013-2016) son ejemplos recientes de intervenciones que combinaron el uso de insecticidas, la ingeniería sanitaria y la disponibilidad de vacunas o medicamentos efectivos, apoyados por la participación comunitaria y otros métodos de control…


Assuntos
Aedes , Mosquitos Vetores , Wolbachia , Controle de Mosquitos , Controle de Vetores , Controle Biológico de Vetores
13.
Vet Parasitol ; 271: 57-63, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31303205

RESUMO

The poultry red mite, Dermanyssus gallinae, is a blood-feeding ectoparasite that affects egg-laying hens worldwide. Strategies to control this parasite have focused in the use of entomopathogenic fungi, such as Metarhizium anisopliae. However, only a few studies have evaluated the use of Aspergillus oryzae to control D. gallinae and none of them have employed native strains. In the work presented here, a novel entomopathogenic fungus was isolated from a dead D. gallinae. The results of phylogenetic analysis showed 100% similarity between the isolated strain and those of two species, A. oryzae and Aspergillus flavus, and 99.82% similarity with A. parvisclerotigenus, which were in the same branch of the Flavi section of the genus Aspergillus. This entomopathogenic fungus was a non-aflatoxin B1 producer, as shown by the presence of aflatoxin B1 in the conidial infection suspension. Morphological features of fungus in comparison with A. oryzae and A. flavus indicated that the isolated strain belonged to A. oryzae, and was named Aspergillus sp. Dg-1. The pathogenicity of Aspergillus sp. Dg-1 on D. gallinae at different life stages was then assessed under laboratory conditions. The experiments showed that the isolated strain significantly increased the mortality rate in adult mites, up to 24.83 ± 2.25, compared to the mortality rates in the control group, which were 15.17 ± 2.75 (P < 0.05). However, Aspergillus sp. Dg-1 did not have pathogenic effects on the second nymph stage of D. gallinae. Our findings demonstrate that Aspergillus sp. Dg-1 has pathogenic effects on D. gallinae in their adult stage, presenting biocontrol potential against D. gallinae.


Assuntos
Aspergillus oryzae/fisiologia , Infestações por Ácaros/microbiologia , Controle Biológico de Vetores , Doenças das Aves Domésticas/terapia , Trombiculidae/microbiologia , Animais , Aspergillus oryzae/classificação , Aspergillus oryzae/genética , Aspergillus oryzae/patogenicidade , Estágios do Ciclo de Vida , Filogenia , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/parasitologia
14.
J Insect Sci ; 19(3)2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31175836

RESUMO

Intensively managed flowering crops like canola (Brassicales: Brassicaceae) (oilseed rape, OSR) provide significant short-term nectar resources for pollen consumers. They may also play important roles as annual "service strips" in temporarily promoting predatory invertebrates. We set out to test this assumption by comparing overall and functional group-specific species richness, activity density, and assemblage composition of carabids (Coleoptera: Carabidae) and spiders (Araneae), in three types of service strips-OSR, woody, and grassy strips established in direct vicinity to cropland. OSR strips were found to harbor the highest carabid species richness and activity density of small carabids. The activity density of carabids overall and of omnivorous species, the species richness and activity density of spiders across size classes and feeding strategies were all significantly reduced in woody strips. The percentage of seminatural habitat in the wider landscape was positively linked to the activity density of spiders overall, ground hunting and large spiders, whereas in carabids, positive effects were limited to large species occurring in grassy strips. Habitat type was the main predictor of both carabid and spider assemblage composition. Our results indicate that carabid and spider activity density across functional groups responded more strongly to changes in the landscape composition than the diversity of individual taxonomic groups. For agricultural landscape management, the establishment of habitat mosaics that include regular OSR could promote abundant, species-rich predatory invertebrates particularly in early spring. In contrast, structurally homogenous woody strips represent limited value in promoting the investigated biological pest control agents.


Assuntos
Agricultura/métodos , Brassicaceae , Besouros , Ecossistema , Aranhas , Animais , Controle Biológico de Vetores , Densidade Demográfica
15.
Ecotoxicol Environ Saf ; 181: 121-129, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176246

RESUMO

Biocides based on toxins of Bacillus thuringiensis var. israelensis (Bti) are established as alternatives to conventional chemical insecticides for mosquito control all across the globe since they are regarded ecologically compatible and harmless to non-target species. Since recent studies on amphibian larvae have called this opinion into question, we exposed Rana temporaria tadpoles to single (1 mg/L), tenfold (10 mg/L) and hundredfold (100 mg/L) field concentrations of VectoBac® WG (a water dispersible granule Bti formulation) in the laboratory for eleven days to investigate whether larvae were adversely affected by Bti and its endotoxin proteins. In addition to a negative (water) control, a positive control based on organic rice protein (50 mg/L) was run to check for the nutritional relevance of Bti proteins. There was no Bti-related mortality and a histopathological analysis of tadpole intestines revealed no adverse effects. Analyses of biomarkers for proteotoxicity (stress protein family, Hsp70) and neurotoxicity or metabolic action (b-esterases acetylcholine esterase (AChE) and carboxylesterases) revealed no significant differences between Bti treatments and the negative control. The responses of tadpoles in the protein-supplemented positive control differed from those of the negative control and the Bti treatments. Tadpoles in the positive control had reduced body mass and elevated AChE activity.


Assuntos
Bacillus thuringiensis , Endotoxinas/toxicidade , Inseticidas/toxicidade , Rana temporaria/crescimento & desenvolvimento , Animais , Larva/efeitos dos fármacos , Controle Biológico de Vetores
16.
Rev Bras Parasitol Vet ; 28(2): 333-337, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31188945

RESUMO

The objectives of this study were to describe occurrences of Rhabditis spp. causing parasitic otitis in dairy cattle of Gir breed in the state of Espírito Santo, southeastern Brazil, and to evaluate the biological control of this nematode using the nematophagous fungi Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34). After nematode detection and collection, three groups were formed: two groups that were treated, respectively, with the fungal isolates; and a control group, without fungus. The treatments were as follows: (a) Petri dishes containing the culture medium 2% water agar (WA) + 250 nematodes + AC001; (b) Petri dishes containing 2% WA + 250 nematodes + NF34; and (c) Petri dishes containing only 2% WA + 250 nematodes. After seven days at 27 °C the treatments with fungi were able to capture and destroy the nematodes, with percentages of 82.0% (AC001) and 39.0% (NF34) in relation to the control group. The results demonstrate the occurrence of Rhabditis spp. after animals physical examination and that there was efficacy of the in vitro predatory activity of both fungal isolates. Thus, these results are important because they can assist in future in vivo control of this nematode in cattle.


Assuntos
Doenças dos Bovinos/parasitologia , Otite/veterinária , Controle Biológico de Vetores/métodos , Infecções por Rhabditida/veterinária , Rhabditoidea/microbiologia , Animais , Ascomicetos/fisiologia , Bovinos , Duddingtonia/fisiologia , Otite/parasitologia , Otite/terapia , Infecções por Rhabditida/terapia
17.
Parasit Vectors ; 12(1): 319, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31238963

RESUMO

BACKGROUND: Bacillus thuringiensis israelensis (Bti) is a widely used mosquitocidal microbial pesticide due to its high toxicity. ATP-binding proteins (ABP) are prevalently detected in insects and are related to reaction against Bti toxins. However, the function of ABP in mosquito biocontrol is little known, especially in Aedes aegypti. Therefore, this study aimed to clarify the function of ABP in Ae. aegypti against Bti toxin. RESULTS: Aedes aegypti ABP (GenBank: XM_001661856.2) was cloned, expressed and purified in this study. Far-western blotting and ELISA were also carried out to confirm the interaction between ABP and Cry11Aa. A bioassay of Cry11Aa was performed both in the presence and absence of ABP, which showed that the mortality of Ae. aegypti is increased with an increase in ABP. CONCLUSIONS: Our results suggest that ABP in Ae. aegypti can modulate the toxicity of Cry11Aa toxin to mosquitoes by binding to Bti toxin. This could not only enrich the mechanism of Bt toxin, but also provide more data for the biocontrol of this transmission vector.


Assuntos
Aedes/genética , Bacillus thuringiensis/patogenicidade , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Aedes/microbiologia , Animais , Proteínas de Bactérias/metabolismo , Bioensaio , Clonagem Molecular , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Mosquitos Vetores/microbiologia , Controle Biológico de Vetores , Ligação Proteica
18.
Food Chem Toxicol ; 129: 376-381, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31054996

RESUMO

The ipd072Aa gene from Pseudomonas chlororaphis encodes the IPD072Aa protein which confers protection against certain coleopteran pests when expressed in genetically modified (GM) plants. A weight of evidence approach was used to assess the safety of the IPD072Aa protein. This approach considered the history of safe use of the source organism and bioinformatic comparison of the protein sequence with known allergenic and toxic proteins. The IPD072Aa protein was assessed for resistance to degradation in the presence of simulated gastric fluid containing pepsin as well as heat stability. There was no hazard identified with the IPD072Aa protein. Furthermore, an acute oral toxicity study found no evidence of adverse effects. Collectively, these studies support the human health safety assessment of the IPD072Aa protein.


Assuntos
Proteínas de Bactérias/farmacologia , Besouros/efeitos dos fármacos , Pseudomonas chlororaphis/metabolismo , Alérgenos/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/toxicidade , Eletroforese em Gel de Poliacrilamida , Controle Biológico de Vetores/métodos , Plantas Geneticamente Modificadas/genética , Testes de Toxicidade , Zea mays/genética
19.
Chemosphere ; 229: 392-400, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31082706

RESUMO

Hippodamia variegata is one of the most abundant ladybird species in Greece, preying on several aphid species and other arthropods, of which many are pests of cultivated plants. Imidacloprid, a neonicotinoid insecticide, is commonly used for controlling sucking insects; at the same time, however, it can cause various sub-lethal effects on non-target organisms. The development of IPM programs against pests requires an evaluation of the side effects of insecticides on natural enemies. We evaluated the sub-lethal effects of imidacloprid on H. variegata. Our results demonstrate that imidacloprid at a LC10 (3.92 mg (a.i.) L-1 and LC30 (8.69 mg (a.i.) L-1) decreased adult longevity and survival rate. In addition, demographic parameters, such as the intrinsic rate of increase (r), finite rate of increase (λ) and net reproductive rate (R0), were reduced when exposed to sub-lethal concentrations of imidacloprid. These results demonstrate a negative influence of imidacloprid at sub-lethal concentrations on H. variegata which could reduce biological control services provided by this predator.


Assuntos
Besouros/efeitos dos fármacos , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Controle Biológico de Vetores , Animais , Afídeos , Besouros/fisiologia , Grécia , Inseticidas/farmacologia , Inseticidas/toxicidade , Longevidade/efeitos dos fármacos , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Reprodução/efeitos dos fármacos
20.
Exp Appl Acarol ; 77(4): 527-543, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31062204

RESUMO

Biological control of spider mites in hot and dry weather is a serious technical issue. A high-temperature adapted strain (HTAS) of the predatory mite Neoseiulus barkeri Hughes was selected from its conventional strain (CS), via long-term heat acclimation and frequent heat hardenings in our previous studies. However, the environment of high temperature is usually associated with enhanced ultraviolet (UV) radiation. In the present study, the physiological effects of UV-B radiation on survival rate and egg damage of N. barkeri were investigated, as well as the activities and expression profiles of antioxidant enzymes to UV-B radiation stress. UV-B radiation had deleterious effects on egg hatchability and survival of N. barkeri. Adults of the HTAS strain were less UV-B resistant than those of the CS strain; they also had lower levels of enzymatic activity of superoxide dismutase (SOD) and catalase against oxidative damage and weaker upregulation of SOD genes. The mRNA expression of three SOD genes of CS adult females immediately increased whereas that of HTAS showed almost no difference under UV-B stress for 1 h. The results showed the HTAS of N. barkeri had lower fitness under UV-B stress compared with the CS of N. barkeri. These results suggested that long-term heat acclimation may exert a profound impact on the developmental physiology of N. barkeri.


Assuntos
Proteínas de Artrópodes/genética , Aptidão Genética/efeitos da radiação , Ácaros/efeitos da radiação , Comportamento Predatório/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Adaptação Biológica , Animais , Antioxidantes/metabolismo , Proteínas de Artrópodes/metabolismo , Feminino , Temperatura Alta , Longevidade/efeitos da radiação , Ácaros/enzimologia , Ácaros/genética , Ácaros/fisiologia , Óvulo/fisiologia , Óvulo/efeitos da radiação , Controle Biológico de Vetores , Transcrição Genética/efeitos da radiação
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