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1.
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
2.
Rev Soc Bras Med Trop ; 52: e20180459, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365621

RESUMO

INTRODUCTION: The ability of Vitex trifolia and Vitex negundo essential oils to kill Aedes aegypti and Culex quinquefasciatus larvae was evaluated. METHODS: The larvae were treated with their respective essential oils at 50-125 ppm concentration. RESULTS: LC50 and LC90 for V. trifolia against Ae. aegypti and C. quinquefasciatus, and those for V. negundo against Ae. aegypti were 57.7+0.4, 77.9+0.9 ppm and 55.17+3.14, 78.28+2.23 ppm, and 50.86+0.9, 73.12+1.3 ppm, respectively. Eucalyptol and caryophyllene were the major components in Vitex trifolia and Vitex negundo essential oil, respectively. CONCLUSIONS: This study revealed potential larvicidal properties of essential oil from V. trifolia.


Assuntos
Aedes/efeitos dos fármacos , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Óleos Voláteis/farmacologia , Vitex/química , Animais , Inseticidas/isolamento & purificação , Dose Letal Mediana , Óleos Voláteis/isolamento & purificação
3.
Cochrane Database Syst Rev ; 8: CD012736, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31425624

RESUMO

BACKGROUND: Larviciding refers to the regular application of chemical or microbial insecticides to water bodies or water containers to kill the aquatic immature forms of the mosquito (the larvae and pupae). OBJECTIVES: To summarize research evidence evaluating whether larviciding with chemical or microbial insecticides prevents malaria transmission. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; CAB Abstracts; LILACS; the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP); ClinicalTrials.gov; and the ISRCTN registry up to 6 June 2019. SELECTION CRITERIA: We included cluster-randomized controlled trials (cRCTs), interrupted time series (ITS), randomized cross-over studies, non-randomized cross-over studies, and controlled before-and-after studies (CBAs) that compared larviciding with no larviciding. DATA COLLECTION AND ANALYSIS: We independently assessed trials for eligibility and risk of bias, and extracted data. We assessed the certainty of evidence using the GRADE approach. MAIN RESULTS: Four studies (one cRCT, two CBAs, and one non-randomized cross-over design) met the inclusion criteria. All used ground application of larvicides (people hand-delivering larvicides); one evaluated chemical and three evaluated microbial agents. Studies were carried out in The Gambia, Tanzania, Kenya, and Sri Lanka. Three studies were conducted in areas where mosquito aquatic habitats were less extensive (< 1 km²), and one where habitats were more extensive (> 1 km²; a cross-over study from The Gambia).For aquatic habitats of less than 1 km², one cRCT randomized eight villages in Sri Lanka to evaluate chemical larviciding using insect growth regulator; and two CBA studies undertaken in Kenya and Tanzania evaluated microbial larvicides. In the cRCT, larviciding across all villages was associated with lower malaria incidence (rate ratio 0.24, 4649 participants, low-certainty evidence) and parasite prevalence (risk ratio (RR) 0.26, 5897 participants, low-certainty evidence) compared to no larviciding. The two CBA studies reported lower malaria prevalence during the intervention period (parasite prevalence RR 0.79, 95% confidence interval (CI) 0.71 to 0.89; 70,902 participants; low-certainty evidence). The Kenyan study also reported a reduction in the incidence of new malaria cases (RR 0.62, 95% CI 0.38 to 1.01; 720 participants; very low-certainty evidence).For aquatic habitats of more than 1 km², the non-randomized cross-over trial using microbial larvicides did not detect an effect for malaria incidence (RR 1.58, 95% CI 0.94 to 2.65; 4226 participants), or parasite prevalence (RR 1.15, 95% CI 0.41 to 3.20; 3547 participants); both were very low-certainty evidence. The Gambia trial also reported the mean haemoglobin level, and there was no difference across the four comparisons (mean difference -0.13, 95% CI -0.40 to 0.13; 3586 participants).We were unable to summarize or pool entomological outcomes due to unreported and missing data. AUTHORS' CONCLUSIONS: Most controlled studies on larviciding have been performed with microbial agents. Ground larviciding for non-extensive larval habitats may have an effect on malaria transmission, and we do not know if there is an effect in large-scale aquatic habitats. We found no studies using larviciding application techniques that could cover large aquatic habitats, such as aerial spraying using aircraft.


Assuntos
Reservatórios de Doenças/parasitologia , Inseticidas/farmacologia , Malária/prevenção & controle , Controle de Mosquitos/métodos , Animais , Culicidae , Ecossistema , Humanos , Análise de Séries Temporais Interrompida , Larva/efeitos dos fármacos , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos
4.
J Agric Food Chem ; 67(33): 9210-9219, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31390203

RESUMO

The insecticidal and antifeedant activities of five 7-chloro-4-(1H-1,2,3-triazol-1-yl)quinoline derivatives were evaluated against the maize armyworm, Spodoptera frugiperda (J.E. Smith). These hybrids were prepared through a copper-catalyzed azide alkyne cycloaddition (CuAAC, known as a click reaction) and displayed larvicidal properties with LD50 values below 3 mg/g insect, and triazolyl-quinoline hybrid 6 showed an LD50 of 0.65 mg/g insect, making it 2-fold less potent than methomyl, which was used as a reference insecticide (LD50 = 0.34 mg/g insect). Compound 4 was the most active antifeedant derivative (CE50 = 162.1 µg/mL) with a good antifeedant index (56-79%) at concentrations of 250-1000 µg/mL. Additionally, triazolyl-quinoline hybrids 4-8 exhibited weak inhibitory activity against commercial acetylcholinesterase from Electrophorus electricus (electric-eel AChE) (IC50 = 27.7 µg/mL) as well as low anti-ChE activity on S. frugiperda larvae homogenate (IC50 = 68.4 µg/mL). Finally, molecular docking simulations suggested that hybrid 7 binds to the catalytic active site (CAS) of this enzyme and around the rim of the enzyme cavity, acting as a mixed (competitive and noncompetitive) inhibitor like methomyl. Triazolyl-quinolines 4-6 and 8 inhibit AChE by binding over the perimeter of the enzyme cavity, functioning as noncompetitive inhibitors. The results described in this work can help to identify lead triazole structures from click chemistry for the development of insecticide and deterrent products against S. frugiperda and related insect pests.


Assuntos
Inseticidas/síntese química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Quinolinas/química , Quinolinas/farmacologia , Spodoptera/efeitos dos fármacos , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Animais , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Química Click , Simulação por Computador , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Inseticidas/química , Larva/enzimologia , Larva/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Doenças das Plantas/parasitologia , Spodoptera/enzimologia , Spodoptera/crescimento & desenvolvimento , Zea mays/parasitologia
5.
Exp Parasitol ; 204: 107719, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255572

RESUMO

The present study was aimed to check the mosquitocidal activity of tiliamosine isolated from Tiliacora acuminata (Lam.) Hook. f. & Thom against immature stages of Culex quinquefasciatus. Eggs and larvae of Cx. quinquefasciatus were exposed to different concentrations of tiliamosine - 0.5, 1.0, 1.5 and 2.0 ppm - prepared using DMSO. The compound tiliamosine showed good larvicidal activity with LC50 and LC90 values of 1.13 and 2.85 ppm respectively, against third-instar larvae of Cx. quinquefasciatus at 24 h. In control, the larvae exhibited normal movement. Tiliamosine exhibited 91% ovicidal activity at 2.0 ppm concentration after 120 h post-treatment. Lowest concentration of tiliamosine (0.5 ppm) showed 19% egg mortality. Histopathology study of the compound-treated larvae showed serious damage on the larval midgut cells. The treated larvae showed restless movement which was different from that of the control larvae. The larvae exhibited malformation in development. The compound tiliamosine was harmless to non-target organisms P. reticulata and Dragon fly nymph at tested concentrations. The compound was highly active and inhibited AChE in a concentration-dependent manner. Computational analysis of the tiliamosine had strong interaction with AChE1 of Cx. quinquefasciatus. This report clearly suggests that the isolated compound can be used as an insecticide to control mosquito population and thus prevent the spread of vector-borne diseases.


Assuntos
Benzilisoquinolinas/farmacologia , Culex/efeitos dos fármacos , Inseticidas/farmacologia , Menispermaceae/química , Mosquitos Vetores/efeitos dos fármacos , Extratos Vegetais/farmacologia , Animais , Culex/crescimento & desenvolvimento , Filariose/prevenção & controle , Filariose/transmissão , Larva/efeitos dos fármacos , Dose Letal Mediana , Ligantes , Simulação de Acoplamento Molecular , Mosquitos Vetores/crescimento & desenvolvimento , Odonatos/efeitos dos fármacos , Óvulo/efeitos dos fármacos , Poecilia
6.
J Agric Food Chem ; 67(32): 8896-8904, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31339308

RESUMO

The mosquito Aedes aegypti is associated with the spread of many viral diseases in humans, including Dengue virus (DENVs), Yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV). Bacillus thuringiensis (Bt) is widely used as a biopesticide, which produces Cry toxins for mosquito control. The Cry toxins bind mainly to important receptors, including alkaline phosphatase (ALP) and aminopeptidase-N (APN). This work investigated the function of a C-type lectin, CTLGA9, in A. aegypti in response to Cry toxins. Our results showed by far-western blot and ELISA methods that the CTLTGA9 protein interacted with brush border membrane vesicles (BBMVs) of A. aegypti larvae and with ALP1, APN, and Cry11Aa proteins. Furthermore, molecular docking showed overlapping binding sites in ALP1 and APN for binding to Cry11Aa and CTLGA9. The toxicity assays further demonstrated that CTLGA9 inhibited the larvicidal activity of Cry toxins. According to the results of molecular docking, CTLGA9 may compete with Cry11Aa for binding to ALP1 and APN receptors and thus decreases the mosquitocidal toxicity of Cry11Aa. Our results provide further insights into better understanding the mechanism of Cry toxins and help improve the Cry toxicity for mosquito control.


Assuntos
Aedes/efeitos dos fármacos , Aedes/metabolismo , Proteínas de Bactérias/toxicidade , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Proteínas de Insetos/metabolismo , Aedes/química , Aedes/genética , Animais , Proteínas de Bactérias/química , Sítios de Ligação , Endotoxinas/química , Proteínas Hemolisinas/química , Proteínas de Insetos/química , Proteínas de Insetos/genética , Larva/efeitos dos fármacos , Larva/genética , Larva/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica/efeitos dos fármacos
7.
Bioengineered ; 10(1): 292-305, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31284815

RESUMO

In the present study, Probit, Cauchy Fractional and three types of Log methods, i.e., Logit, Log-log, and Complementary log-log were employed to model the feeding deterrence of the lesser grain borer, Rhyzopertha dominica (F) (Coleoptera: Bostrichidae), when fed latex protein, crude flavonoid fraction, 3-O-rutinosides of quercetin, kaempferol and isorhamnetin, isolated from Calotropis procera (Ait.) (Gentianales: Asclepiadaceae). A nutritional study with treated flour discs at sub-lethal concentrations indicated that the tested natural products negatively affected the feeding behavior of the lesser grain borer, causing high feeding deterrent indices. Our results assure that Probit, Logit and Clog-log model the feeding deterrent indices with high goodness of fit. The models aim to support the management of the test insect when fed grains treated with sub-lethal doses of the tested phytochemicals in order to develop a viable, precise and long-term strategy to minimize the excessive reliance on the chemical pesticides currently in use.


Assuntos
Produtos Biológicos/farmacologia , Calotropis/química , Besouros/efeitos dos fármacos , Quempferóis/farmacologia , Modelos Estatísticos , Quercetina/análogos & derivados , Quercetina/farmacologia , Animais , Besouros/fisiologia , Grão Comestível/parasitologia , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Glicosídeos/farmacologia , Larva/efeitos dos fármacos , Larva/fisiologia , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Triticum/parasitologia
8.
World J Microbiol Biotechnol ; 35(7): 106, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31267229

RESUMO

Xenorhabdus nematophila HB310 secreted the insecticidal protein toxin complex. Two chitinase genes, chi60 and chi70, were found in X. nematophila toxin complex locus. In order to clarify the function of two chitinases, chi60 and chi70 genes were cloned and expressed in Escherichia coli Transetta (DE3). As a result, we found that the Chi60 and Chi70 belonged to glycoside hydrolases (GH) family 18 with a molecular mass of 65 kDa and 78 kDa, respectively. When colloidal chitin was treated as the substrate, Chi60 and Chi70 were proved to have the highest enzymatic activity at pH 6.0 and 50 °C. Chi60 and Chi70 had obvious growth inhibition effect against the second larvae of Helicoverpa armigera with growth inhibiting rate of 81.99% and 90.51%. Chi70 had synergistic effect with the insecticidal toxicity of Bt Cry 1Ac, but the Chi60 had no synergistic effect with Bt Cry 1Ac. Chi60 and Chi70 showed antifungal activity against Alternaria brassicicola, Verticillium dahliae and Coniothyrium diplodiella. The results increased our understanding of the chitinases produced by X. nematophila and laid a foundation for further studies on the mechanism of the chitinases.


Assuntos
Antifúngicos/farmacologia , Quitinases/antagonistas & inibidores , Quitinases/genética , Quitinases/metabolismo , Xenorhabdus/metabolismo , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Quitina/metabolismo , Quitinases/classificação , Clonagem Molecular , Sinergismo Farmacológico , Ensaios Enzimáticos , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Inseticidas/metabolismo , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Peso Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Micotoxinas/genética , Micotoxinas/metabolismo , Filogenia , Domínios Proteicos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Temperatura Ambiente , Verticillium/efeitos dos fármacos , Xenorhabdus/genética
9.
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
10.
Ecotoxicol Environ Saf ; 181: 381-387, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31212186

RESUMO

The effects of Bt Cry9Ee toxin on honey bee, Apis mellifera L., survival, developmental rate, larval weight, pollen consumption, and midgut bacterial diversity were tested in the laboratory. Honey bee larvae and adults were reared in vitro and fed a diet that contained Cry9Ee toxin at 0.01, 0.1, 1, and 10 mg/L. Cry9Ee toxin 0.01, 0.1, and 1 mg/L in diet used in this study may represent a value closer to field relevance and the highest concentration is unlikely to be encountered in the field and thus represent a worst case scenario. The dependent variables were compared for groups of honey bees feeding on treated diet and those feeding on negative control (no addition of a test substance), solvent control (0.01 mM Na2CO3), and positive control diet (dimethoate 45 mg/L). Bt Cry9Ee toxin did not affect survival or larval weight, and the result was great confidence in accepting the null hypothesis by power analysis. The effect on development rates and pollen consumption were the inconclusive results because the post-hoc power was less than 0.8. Furthermore, the midgut bacterial structure and compositions were determined using high-throughput sequencing targeting the V3-V4 regions of the 16S rDNA. All core honey bee intestinal bacterial class such as γ-Proteobacteria, Actinobacteria, α-Proteobacteria, Bacilli, ß-Proteobacteria, and Bacteroidia were detected, and no significant changes were found in the species diversity and richness between Cry9Ee treatments and laboratory control.


Assuntos
Proteínas de Bactérias/toxicidade , Abelhas/efeitos dos fármacos , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Animais , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Abelhas/crescimento & desenvolvimento , Sistema Digestório/microbiologia , Larva/efeitos dos fármacos , Pólen
11.
J Chem Ecol ; 45(7): 638-648, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31227972

RESUMO

Although the production of phytohormones has been commonly associated with production of plant defence and stress-related traits, few studies have simultaneously investigated this phenomenon across several plant species that grow along large-scale ecological gradients. To address these knowledge gaps, we performed a common garden experiment with six Cardamine species, which collectively encompass an elevational gradient of 2000 m. We quantified constitutive and Pieris brassicae caterpillars-induced phytohormones and chemical defences in leaves. We found a correlated expression of phytohormone production and the subsequent induction of chemical defences, and this correlated expression reduced herbivore performance. Furthermore, we found that abiotic conditions associated with the optimal elevation range of each species influenced the production of phytohormones and chemical defences, as well as plant growth and productivity. In particular, we found that plant species adapted to milder abiotic conditions at low elevations grew faster, were more productive and produced greater levels of chemical defences. In contrast, plant species adapted to harsher abiotic conditions at high elevations tended to produce greater levels of defence-related oxylipins. Overall, these findings highlight the importance of disentangling the role of phytohormones in mediating plant adaptations to shifting biotic and abiotic conditions.


Assuntos
Cardamine/química , Glucosinolatos/química , Himenópteros/fisiologia , Reguladores de Crescimento de Planta/química , Animais , Cardamine/metabolismo , Cromatografia Líquida de Alta Pressão , Glucosinolatos/farmacologia , Herbivoria , Interações Hospedeiro-Parasita/efeitos dos fármacos , Himenópteros/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/fisiologia , Reguladores de Crescimento de Planta/farmacologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Espectrometria de Massas em Tandem
12.
Nat Commun ; 10(1): 2869, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253776

RESUMO

Clostridial neurotoxins, including tetanus and botulinum neurotoxins, generally target vertebrates. We show here that this family of toxins has a much broader host spectrum, by identifying PMP1, a clostridial-like neurotoxin that selectively targets anopheline mosquitoes. Isolation of PMP1 from Paraclostridium bifermentans strains collected in anopheline endemic areas on two continents indicates it is widely distributed. The toxin likely evolved from an ancestral form that targets the nervous system of similar organisms, using a common mechanism that disrupts SNARE-mediated exocytosis. It cleaves the mosquito syntaxin and employs a unique receptor recognition strategy. Our research has an important impact on the study of the evolution of clostridial neurotoxins and provides the basis for the use of P. bifermentans strains and PMP1 as innovative, environmentally friendly approaches to reduce malaria through anopheline control.


Assuntos
Anopheles/efeitos dos fármacos , Toxinas Bacterianas/farmacologia , Neurotoxinas/farmacologia , Sequência de Aminoácidos , Animais , Bactérias/metabolismo , Larva/efeitos dos fármacos , Modelos Moleculares , Conformação Proteica , Domínios Proteicos
13.
Mar Pollut Bull ; 142: 54-57, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31232336

RESUMO

Plastic debris in the oceans is a major and growing problem in global environmental pollution. There are increasing concerns that plastic debris is a source of contaminant, either added during manufacturing or adsorbed from the environment. However, there is little information about the acute toxicity of leachates from plastic debris on marine organisms. In this study, we conducted experiments to evaluate the toxicity of leachates from two single-use polyethylene plastic bags (PB1 and PB2) with the embryo and larvae of the commercial clam Meretrix meretrix. Results showed that fertilization of the embryos was not affected by plastic leachates, but the developments of D-veliger larvae, including survival, deformity, and shell height, were significantly affected by plastic leachates from both PB1 and PB2 compared to the controls of filtered seawater. We speculate that compounds leaching from plastic bags are responsible for the observed toxicity. Therefore, leaching toxicity from plastic debris should be considered when assessing the risks of plastic pollution in the oceans.


Assuntos
Bivalves/efeitos dos fármacos , Polietileno/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bivalves/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Alimentos Marinhos , Água do Mar
14.
Environ Pollut ; 251: 879-884, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234253

RESUMO

Genotoxic analyses are commonly used in ecotoxicological studies as early biomarkers to investigate the potential effects of environmental contaminants on biological models. Several pollutants can induce DNA damage and, therefore, counting micronuclei and other nuclear abnormalities are efficient tools to evaluate genotoxicity. Some pollutants such as 4-nonylphenol (NP), a detergent used mainly in industries, and Cyproterone Acetate (CPA), an antiandrogenic medicine, have already shown genotoxic effects on some vertebrates. However, although amphibians are considered bioindicators of environmental quality and their populations are declining worldwide, the effects of these compounds on anurans are not yet known and, therefore, we believe that it is important to investigate such effects on anurans. Since water contamination is one of the ultimate causes of amphibian decline, ecotoxicological studies are important to discuss the appropriate solutions to avoid species extinction. Thus, this study investigates the genotoxic effects on Rana catesbeiana tadpoles and juveniles after being exposed to 1, 10 and 100 µg/L NP and 0.025, 0.25 and 2.5 ng/L CPA, by counting the nuclear abnormalities after exposure. The laboratory experiments lasted 28 days. The experimental conditions were the same except for the water volume since tadpoles and juveniles exhibit different habits at different developmental stages. Compared to juveniles, tadpoles were more susceptible to both compounds as indicated by the increased nuclear abnormalities observed in the highest NP concentration and all tested CPA concentrations. The juveniles, on the other hand, responded only to the two highest CPA concentrations. We concluded that CPA, even at very low concentrations, is extremely harmful to both anuran developmental stages and, particularly, to tadpoles. The significant effects observed on tadpoles is an important outcome of this study since 100 µg/L or higher NP concentrations are frequently detected in the environment.


Assuntos
Anuros/embriologia , Acetato de Ciproterona/toxicidade , Larva/efeitos dos fármacos , Fenóis/toxicidade , Rana catesbeiana/embriologia , Poluentes Químicos da Água/toxicidade , Animais , Anuros/genética , Núcleo Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/genética , Poluição Ambiental , Larva/crescimento & desenvolvimento , Rana catesbeiana/genética
15.
Arch Insect Biochem Physiol ; 101(4): e21588, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31180585

RESUMO

Boric acid (BA) is widely used in various industrial process and can be accessed to nontarget organisms. This study aimed to investigate the insecticidal effects of BA and its toxic activities with respect to immunologic and genotoxic effects using Galleria mellonella larvae as a model. BA concentrations (78.125-10,000 ppm) were administrated to the larvae using the feeding method. Concentration-dependent mortality was observed in all larval groups. Probit analysis revealed LC30 , LC50 , and LC70 values to be 112.4, 320.1, and 911.4 ppm, respectively. These concentrations were used in all bioassays. Drastic reductions in total hemocyte counts along with changes in differential hemocyte counts were observed following BA treatment. Cell viability assays showed dose-dependent reductions in viable cells and an increase in the necrotic and apoptotic ratios after BA treatment. However, mitotic indices of larval hemocytes did not change at all BA concentrations. The cytotoxic effect of BA led to a significant reduction in cellular immune responses such as encapsulation, melanization, and nodulation activities of treated larvae. While BA increased micronucleus ratios at the highest concentration, comet parameters indicating DNA damage increased in G. mellonella larval hemocytes at all concentrations. These report that BA suppresses the immune system of G. mellonella and also poses risks of genotoxicity at high concentrations.


Assuntos
Ácidos Bóricos/toxicidade , Mariposas/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ensaio Cometa , Relação Dose-Resposta a Droga , Hemócitos/efeitos dos fármacos , Hemolinfa , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Larva/genética , Larva/imunologia , Testes para Micronúcleos , Mariposas/genética , Mariposas/imunologia
16.
Ecotoxicol Environ Saf ; 181: 106-113, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176244

RESUMO

Oil spills have polluted the marine environment for decades and continue to be a major source of polycyclic aromatic hydrocarbons (PAHs) to marine ecosystems around the globe, for example during the 2010 Deepwater Horizon spill. Although the toxicity of PAHs to fish has been well studied, their effects combined with abiotic stressors are poorly understood. The goal of this study was to describe the combined impacts of crude oil and environmental stressors on fish larvae, a sensitive life stage. Gulf killifish (Fundulus grandis) larvae (<24 h post-hatch) were exposed for 48 h to high energy water accommodated fractions (HEWAF; total PAHs 0-125 ppb) of Macondo oil from the Deepwater Horizon spill under different combinations of environmental conditions (dissolved oxygen 2, 6 ppm; temperature 20, 25, 30 °C; salinity 3, 10, 30 ppt). Even under optimal environmental conditions (25 °C, 10 ppt, 6 ppm) larval survival and development were negatively affected by PAHs, starting with the lowest concentration tested (∼15 ppb). Hypoxia and high temperature each increased the adverse effects of HEWAF on development and mortality. In contrast, salinity had little effect on any of the endpoints measured. Importantly, expression of the detoxifying gene cyp1a was highly induced in PAH-exposed larvae under normoxic conditions, but not under hypoxic conditions, potentially explaining the enhanced toxicity observed under hypoxia. This work highlights the importance of considering how suboptimal environmental conditions can exacerbate the effects of pollution on fish early life stages.


Assuntos
Fundulidae/crescimento & desenvolvimento , Poluição por Petróleo , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Hipóxia/veterinária , Larva/efeitos dos fármacos , Poluição por Petróleo/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Salinidade , Temperatura Ambiente
17.
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
18.
J Sci Food Agric ; 99(13): 5962-5968, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31215022

RESUMO

BACKGROUND: Cadra (=Ephestia) cautella (Walker) is a serious cosmopolitan pest that can feed on a wide variety of stored foods. It is controlled mainly by fumigation with phosphine, to which strong resistance has been documented in major stored-product insects in many countries. The need for reliable, user- and environmentally friendly alternatives is therefore high on the agenda to avoid the development of potential resistance and to reduce human exposure to toxic insecticides. Two modified atmospheres (MAs) composed of high carbon dioxide (CO2 ) and low oxygen (O2 ) (90% and 96% CO2 in air) were studied at the laboratory at 20 °C and 65 ± 3% relative humidity (RH) against C. cautella. RESULTS: Eggs (1, 2, and 3 days old), young and mature larvae (10 and 20 days old), pupae (1, 2 and 3 days old) and adults (1 day old) were exposed to two MAs consisting of high CO2 and low O2 for the range of 2 to 104 h. Eggs, old larvae, and pupae were found to be the most tolerant. Adults were rather easily killed and young larvae were the most susceptible. Lethal exposure time (LT99 ) values were between 11.74 h and 128.97 h. CONCLUSION: Modified atmospheres consisting of high CO2 and low O2 offer an affordable combination to control C. cautella effectively. From the perspective of economics and efficacy, 90% CO2 might be the concentration of choice. © 2019 Society of Chemical Industry.


Assuntos
Dióxido de Carbono/farmacologia , Controle de Insetos/métodos , Mariposas/efeitos dos fármacos , Animais , Atmosfera/análise , Dióxido de Carbono/análise , Controle de Insetos/instrumentação , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Oxigênio/análise , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento
19.
Vet Parasitol ; 270: 13-19, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31213236

RESUMO

Small ruminants browsing in tropical forests readily consume the foliage of Senegalia gaumeri. A S. gaumeri methanol:water extract was recently shown to have ovicidal activity against Haemonchus contortus eggs in vitro. In the present study, the fraction of a S. gaumeri methanol:water extract with ovicidal activity against H. contortus eggs and the metabolites potentially involved in this activity were identified. Bio-guided fractionation of the S. gaumeri methanol:water extract identified high ovicidal activity (80.29%, EC50 = 58.9 µg/mL) in the non-polar sub-fraction P1. Gas chromatography-mass spectrometry (GC-MS) identified several fatty acids: pentacosane (18.05%), heneicosane (18.05%), triacontane (30.94%), octacosane (18.05%), and hexanedioic acid bis-(2-ethylhexyl) ester (32.72%). Purification of the polar components of sub-fraction P1 led to the identification of p-coumaric acid as a major constituent. In egg hatch tests, 400 µg/mL p-coumaric acid resulted in an ovicidal effect of 8.7%, a larvae failing eclosion effect of 2.9%, and of the emerged larvae (88.4%), many were damaged. In conclusion, the low AH activity of p-coumaric acid against H. contortus eggs indicates that it is not solely responsible for the ovicidal activity of sub-fraction P1 but might act in synergy with other compounds in this fraction. However, p-coumaric acid showed potential anthelmintic effects against the larval stage of H. contortus.


Assuntos
Anti-Helmínticos/isolamento & purificação , Anti-Helmínticos/farmacologia , Fracionamento Químico/métodos , Fabaceae/química , Haemonchus/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Animais , Larva/efeitos dos fármacos , Óvulo/efeitos dos fármacos , Folhas de Planta/química
20.
Vet Parasitol ; 270: 25-30, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31213238

RESUMO

This study evaluated the in vitro anthelmintic (AH) activity of cinnamic acid and six analogues against eggs and larvae of Haemonchus contortus. Stock solutions of each compound (trans-cinnamic acid, p-coumaric acid, caffeic acid, trans-ferulic acid, trans-sinapic acid, 3,4-dimethoxycinnamic acid, and chlorogenic acid) were prepared in PBS:Tween-20 (1%) for use in the egg hatch test (EHT) and larval exsheathment inhibition test (LEIT) at different concentrations (25-400 µg/mL). The respective effective concentration 50% (EC50) values with 95% confidence intervals were estimated. Mixtures made of all cinnamic acid and its analogues as well as some selected individual compounds were also tested in the EHT. Only ferulic and chlorogenic acids showed AH activity in the EHT (EC50: 245.2 µg/mL (1.26 mM) and 520.8 µg/mL (1.47 mM), respectively) (P < 0.05). A higher EC50 (1628.10 µg/mL) of the mixture of cinnamic acid and its analogues was required to observe activity against eggs mostly blocking the larvae hatching. The analogues' mixtures tested were less active than ferulic or chlorogenic acid alone. The activity of ferulic and chlorogenic acids against eggs was associated with larvae failing to hatch, and the two compounds exhibited antagonistic effects when evaluated together. All standards had an EC50 lower than 0.42 mM in the LEIT. Caffeic acid had the best activity in the LEIT (EC50 0.04 mM), followed by ferulic acid (EC50 0.11 mM) (P < 0.05). There was no clear, definitive structure-activity relationship for these non-flavonoid polyphenols against eggs or larvae of H. contortus in vitro. This study is the first to directly evaluate cinnamic acid and its derivatives as active compounds against eggs and larvae of H. contortus.


Assuntos
Cinamatos/farmacologia , Haemonchus/efeitos dos fármacos , Animais , Anti-Helmínticos/farmacologia , Cinamatos/química , Concentração Inibidora 50 , Larva/efeitos dos fármacos , Óvulo/efeitos dos fármacos
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