Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 937
Filtrar
1.
Phytopathology ; 110(2): 336-344, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31524559

RESUMO

The endophytic bacterium Bacillus cereus BCM2 has shown great potential as a biocontrol organism against Meloidogyne incognita, which causes severe root-knot diseases in crops. In our previous study, the metabolite of BCM2 showed high nematicidal activity against the M. incognita second-stage juveniles. However, the mechanism employed by endophytic bacteria to infect and kill nematodes is still unclear. Here, we investigate both the endophytic bacterial extracellular proteins with nematicidal activity and their mechanism of killing nematodes. The first step was detecting the nematicidal activities of crude proteins. The results show that the nematode mortality rate reached 100% within 72 h, and the crude proteins damaged both the cuticle and eggshell, before finally destroying the targets. This suggests possible proteinaceous pathogeny in BCM2. Throughout the process, the fine-detail changes in the nematode cuticle and the intestinal structure were observed using scanning electron microscopy and transmission electron microscopy. These images show that BCM2 extracellular proteins did not damage the internal organization of the nematode but did severely damage its cuticle, which led to content leakage. From the crude proteins, chitosanase, alkaline serine protease, and neutral protease were purified and identified. The M. incognita-B. cereus BCM2 microenvironment simulation demonstrates that BCM2 adheres to the surface of nematodes and helps the metabolites that were produced by BCM2 to rapidly recognize and kill M. incognita. This relationship between plants, endophytic bacteria, and nematodes offers insight into the biological mechanisms that can be utilized for of nematode management.


Assuntos
Bacillus cereus , Peptídeo Hidrolases , Tylenchoidea , Animais , Antinematódeos/metabolismo , Antinematódeos/farmacologia , Bacillus cereus/enzimologia , Peptídeo Hidrolases/metabolismo , Peptídeo Hidrolases/farmacologia , Doenças das Plantas/parasitologia , Tylenchoidea/efeitos dos fármacos
2.
PLoS Negl Trop Dis ; 13(12): e0006927, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31841501

RESUMO

BACKGROUND: Schistosomiasis is one of the world's most common NTDs. Successful control operations often target snail vectors with the molluscicide niclosamide. Little is known about how niclosamide affects snails, including for Biomphalaria pfeifferi, the most important vector for Schistosoma mansoni in Africa. We used Illumina technology to explore how field-derived B. pfeifferi, either uninfected or harboring cercariae-producing S. mansoni sporocysts, respond to a sublethal treatment of niclosamide. This study afforded the opportunity to determine if snails respond differently to biotic or abiotic stressors, and if they reserve unique responses for when presented with both stressors in combination. We also examined how sporocysts respond when their snail host is treated with niclosamide. PRINCIPAL FINDINGS: Cercariae-producing sporocysts within snails treated with niclosamide express ~68% of the genes in the S. mansoni genome, as compared to 66% expressed by intramolluscan stages of S. mansoni in snails not treated with niclosamide. Niclosamide does not disable sporocysts nor does it seem to provoke from them distinctive responses associated with detoxifying a xenobiotic. For uninfected B. pfeifferi, niclosamide treatment alone increases expression of several features not up-regulated in infected snails including particular cytochrome p450s and heat shock proteins, glutathione-S-transferases, antimicrobial factors like LBP/BPI and protease inhibitors, and also provokes strong down regulation of proteases. Exposure of infected snails to niclosamide resulted in numerous up-regulated responses associated with apoptosis along with down-regulated ribosomal and defense functions, indicative of a distinctive, compromised state not achieved with either stimulus alone. CONCLUSIONS/SIGNIFICANCE: This study helps define the transcriptomic responses of an important and under-studied schistosome vector to S. mansoni sporocysts, to niclosamide, and to both in combination. It suggests the response of S. mansoni sporocysts to niclosamide is minimal and not reflective of a distinct repertoire of genes to handle xenobiotics while in the snail host. It also offers new insights for how niclosamide affects snails.


Assuntos
Antinematódeos/farmacologia , Biomphalaria/efeitos dos fármacos , Moluscocidas/farmacologia , Niclosamida/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Biomphalaria/genética , Perfilação da Expressão Gênica , Schistosoma mansoni/genética
3.
Exp Parasitol ; 206: 107769, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31580876

RESUMO

BACKGROUND: Mansonellosis arises from infections with threadlike filarial nematodes in millions of individuals, especially in sub-Saharan Africa. Since infections present no overt clinical symptoms but attenuate immune responses that might lead to increased susceptibility and worsened disease course of concomitant infections, it is truly a neglected tropical disease. Nevertheless, only few studies focus on identifying suitable safe drugs for its control and little is known about the requirements for in vitro maintenance of the Mansonella perstans transmission stage. This study, therefore, evaluated the survival of M. perstans microfilariae (mf) using in vitro conditions that have been shown to promote survival of Loa loa, a closely related filarial nematode. Furthermore, the in vitro microfilaricidal effect of 15 agents was assessed on this helminth. METHODS: The ability of two basic culture media; Dulbecco's Modified Eagle's Medium (DMEM) and Roswell Park Memorial Institute (RPMI-1640) supplemented with 10% fetal bovine serum (FBS) and a monkey kidney epithelial cell line (LLC-MK2) to support the survival of M. perstans microfilariae was investigated. Subsequently, 6 anti-helminthics, 5 anti-malarials, 1 anti-microbacterial, 2 trypanocidals and 1 anti-cancer agent were tested in vitro against mf. The suitability of the culture media as well as the effect of the anti-infective agents on mf survival was assessed by scoring their motility. RESULTS: FBS supplement and additional LLC-MK2 cells significantly improved the survival of mf in DMEM and RPMI-1640 culture. In detail, RPMI-1640 supplemented with 10% FBS and LLC-MK2 cells sustained the maintenance of mf for at least 20 days (100.00 ±â€¯0.00% survival). In co-cultures with LLC-MK2 cells without serum, M. perstans mf were maintained in DMEM and RPMI-1640 medium with a motility above 99% by day 5. Mefloquine displayed the highest microfilaricidal effect in vitro followed by artesunate. CONCLUSION: Both RPMI and DMEM in the presence of LLC-MK2 cells are suitable for the maintenance of M. perstans mf in vitro. In absence of the feeder cells, the addition of 10% FBS to RPMI-1640 medium improved the parasite survival rate and motility. The microfilaricidal activity of mefloquine and artesunate on M. perstans mf was documented for the first time in this study and can therefore be considered as reference for further screening of agents against this parasite stage.


Assuntos
Artesunato/farmacologia , Filaricidas/farmacologia , Mansonella/efeitos dos fármacos , Mansonella/crescimento & desenvolvimento , Mefloquina/farmacologia , Amodiaquina/farmacologia , Animais , Antimaláricos/farmacologia , Antinematódeos/farmacologia , Área Sob a Curva , Bovinos , Linhagem Celular , Meios de Cultura/química , Haplorrinos , Ivermectina/farmacologia , Mansonella/fisiologia , Microfilárias/efeitos dos fármacos , Microfilárias/crescimento & desenvolvimento , Microfilárias/fisiologia , Movimento/efeitos dos fármacos , Rifampina/farmacologia
4.
Molecules ; 24(20)2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31600927

RESUMO

Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, is a serious forest pest, causing enormous economic losses in pine trees in Korea, China, Japan, and countries in Western Europe. To prevent pine wilt disease (PWD), trunk injection with nematicide is performed in Korea. Although these nematicidal agents are quite efficient, the development of new nematicidal agents is needed to prevent pesticide resistance and reduce pest management costs. The aim of this study was to investigate nematicidal activities of pure naphthoquinones (NTQs)-1,4-NTQ, juglone, and plumbagin-against B. xylophilus via in vitro and semi-in vivo assays to identify new candidate agents for trunk injection. Estimated LC50 values (48 h exposure) were 100.0 ppm, 57.0 ppm, and 104.0 ppm for 1,4-NTQ, juglone, and plumbagin, respectively. In the semi-in vivo assay on pine bolt of the Japanese black pine, Pinus thunbergii, the population of inoculated B. xylophilus was significantly decreased at two weeks after treatment with juglone when compared with the effects of treatment with 1,4-NTQ and plumbagin. We also observed that naphthoquinones could generate reactive oxygen species, which presumably indicated that naphthoquinones caused significant oxidative stress in B. xylophilus. The findings of this study suggest the nematicidal potential of naphthoquinones and their possible use in further in vivo assays to test their nematicidal efficacy against B. xylophilus when injected through trunk injection.


Assuntos
Antinematódeos/farmacologia , Naftoquinonas/farmacologia , Tylenchida/efeitos dos fármacos , Animais , Antinematódeos/química , Relação Dose-Resposta a Droga , Estrutura Molecular , Naftoquinonas/química , Testes de Sensibilidade Parasitária , Pinus/metabolismo , Pinus/parasitologia , Espécies Reativas de Oxigênio
5.
Plant Dis ; 103(12): 3161-3165, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545697

RESUMO

The southern root-knot nematode (RKN), Meloidogyne incognita, is particularly difficult to manage because of high susceptibility of all commercial cucumber (Cucumis sativus) cultivars to this nematode. Growers have conventionally relied on nematicide applications to control RKN. Two microplot experiments were conducted in which four nonfumigant nematicides, oxamyl, fluopyram, fluensulfone, and fluazaindolizine, were examined for their efficacy in reducing gall severity and postharvest soil nematode numbers in microplots inoculated with increasing inoculation densities (1,000, 5,000, 10,000, and 20,000 nematodes/microplot), and improving growth and yield of cucumber. Nematicides were applied 1 day prior to transplanting cucumber seedlings, except fluensulfone, which was applied 7 days before transplanting. At harvest, root gall indices differed significantly (P < 0.0001) among nematode inoculation densities and nematicides. All four nematicides were effective in reducing the root gall index when compared with the untreated control on a consistent basis at all M. incognita inoculation densities. At the lowest inoculation density, no significant difference in gall index or final population density was observed among nematicides; however, gall index increased with increasing nematode inoculation densities in nematicide-treated microplots. Correlations between gall index and inoculation density clearly showed that soil treatment with fluensulfone, fluazaindolizine, or fluopyram was more effective in reducing gall severity than treatment with oxamyl. Regression analysis also indicated no significant effect of nematode inoculation densities on yield of cucumber treated with these nematicides. Results of this study will provide guidance for improving nematicide efficiencies in soil with varying inoculation densities of RKN.


Assuntos
Antinematódeos , Cucumis sativus , Tylenchoidea , Animais , Antinematódeos/farmacologia , Cucumis sativus/parasitologia , Densidade Demográfica , Solo/parasitologia , Tylenchoidea/efeitos dos fármacos
6.
Carbohydr Polym ; 224: 115155, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472825

RESUMO

Plant-parasitic nematodes cause substantial crop losses annually; however, current nematicides are environmentally unfriendly and highly toxic to nontarget organisms. The development of green efficient nematicides from multifunctional natural bioactive substances such as chitin oligosaccharide (COS) is promising. In this paper, COS dithiocarbamate derivatives (COSDTC, COSDTA, COSDTB) were synthesized to increase nematicidal activity (against Meloidogyne incognita), and their structures were characterized by FTIR, NMR, TGA/DTG and elemental analysis. Furthermore, the nematicidal activities, egg hatching inhibitory activities, plant growth adjustment abilities, cytotoxicity and phytotoxicity of the derivatives were evaluated. The primary mechanism was assessed by heavy metal ion absorption and GSH-binding assays. The results showed COS dithiocarbamate derivatives could possess multiple efficacies, including high nematicidal activities and egg hatching inhibitory activities, plant growth regulating effects, low cell toxicities and phytotoxicities. Additionally, it was inferred that nematicidal activity may be correlated with GSH-binding activity but not heavy metal ion complexation. COS modification has immense potential for controlling plant-parasitic nematodes.


Assuntos
Antinematódeos/química , Antinematódeos/farmacologia , Quitina/química , Quitina/farmacologia , Oligossacarídeos/química , Tiocarbamatos/química , Tylenchoidea/efeitos dos fármacos , Animais , Antinematódeos/metabolismo , Antinematódeos/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Quitina/metabolismo , Quitina/toxicidade , Glutationa/metabolismo , Humanos , Células MCF-7
7.
In Vivo ; 33(5): 1463-1468, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31471393

RESUMO

BACKGROUND/AIM: Breast cancer is characterized by a high rate of mortality and is considered one of the deadliest types of cancer. It is of note that (-)-epigallocatechin-3-gallate (EGCG), the principal catechin of green tea, is able to hinder the growth of MDA-MB-231 breast cancer cells by influencing different signaling pathways, including apoptosis. Furthermore, EGCG is also used in the treatment of bone cancer pain. Tapentadol, an opioid drug acting at the level of noradrenaline (norepinephrine) reuptake inhibition and µ-opioid receptor, is able to modulate bone cancer pain and influence cancer cell viability by regulating apoptosis. MATERIALS AND METHODS: In vitro assays were performed on triple-negative MDA-MB-231 cells treated with tapentadol (1, 5, 10, 20, 40 and 80 µg/ml) and EGCG (1, 10, 20, 40, 80, 160 µmol/l), alone and in combination. The effects of EGCG and TAP on viability were determined by wound-healing and MTT assays, while cell migration was assessed by transwell migration. RESULTS: Cell proliferation, viability and apoptosis of MDA-MB-231 cells were impaired by the combination of EGCG and tapentadol. Specifically, our data show that EGCG and TAP reduced the proliferation of MDA-MB-231 cells by impairing cell-cycle progression (p<0.05). These findings suggest that the combination of these substances may represent a new strategy for the treatment of patients suffering from triple-negative breast cancer.


Assuntos
Antinematódeos/farmacologia , Catequina/análogos & derivados , Tapentadol/farmacologia , Apoptose/efeitos dos fármacos , Catequina/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Neoplasias de Mama Triplo Negativas
8.
Exp Parasitol ; 205: 107734, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31394093

RESUMO

Parasitism by Haemonchus contortus is one of the main limiting factors in small ruminant production around the globe. Although several studies suggest the use of integrated management practices, these parasites have been controlled essentially with synthetic anthelmintic drugs. The resistance mechanism against the imidazothiazole derivative levamisole in Haemonchus contortus has not been fully described. Recently, resistance was associated with a 63bp deletion in the Hco-acr-8b gene that encodes a subunit for a nicotinic acetylcholine receptor. This study aimed to standardize a real time PCR (qPCR) protocol for levamisole resistance diagnosis in H. contortus populations based on this polymorphism and use it to characterize 23 field H. contortus populations obtained from different localities of Ceará State, Northeast Brazil. In addition, two populations of H. contortus were used as a standard of susceptibility and resistance, Inbred Strain Edinburgh (ISE) and Kokstad, respectively. Larval development tests (LDT) were performed on five field isolates and both EC50 and EC95 were estimated. LDT EC95 values provided a wider interval between susceptible and resistant populations than EC50 values (EC95 = 1.96-57.93 µM; EC50 = 0.05-0.39 µM), and were found to be more appropriate for differentiating them. Real time PCR results showed resistance allele frequencies ranged from 20.9 to 76.7%. Our results suggest that levamisole resistance may be present in field populations but it is not as widespread as benzimidazole resistance. This methodology may be useful to monitor levamisole resistance in field populations of H. contortus.


Assuntos
Antinematódeos/farmacologia , Resistência a Medicamentos/genética , Haemonchus/efeitos dos fármacos , Levamisol/farmacologia , Animais , Benzimidazóis/farmacologia , DNA de Helmintos/isolamento & purificação , Fezes/parasitologia , Frequência do Gene/genética , Hemoncose/tratamento farmacológico , Hemoncose/parasitologia , Hemoncose/veterinária , Haemonchus/genética , Haemonchus/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Junção Neuromuscular/efeitos dos fármacos , Junção Neuromuscular/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Receptores Colinérgicos/efeitos dos fármacos , Receptores Nicotínicos/efeitos dos fármacos , Alinhamento de Sequência/veterinária , Ovinos , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/parasitologia , Tetramizol/farmacologia
9.
Plant Dis ; 103(9): 2191-2198, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31293210

RESUMO

Tea-oil camellia (Camellia oleifera) is grown for tea seed oil production, with tea seed cake produced as a byproduct. Rather than disposing of the cake, agricultural uses increase the value of oil production. Constituents of C. oleifera are also utilized for traditional Chinese medicine, as are compounds produced by tree peony roots. Consequently, the unused C. oleifera cake, and stems from two tree peony species, Paeonia rockii and Paeonia suffruticosa, were studied for compounds antagonistic to soybean cyst nematode (Heterodera glycines) and root-knot nematode (Meloidogyne incognita). Extracts from C. oleifera cake and P. rockii stems suppressed hatch and were nematotoxic to second-stage juveniles (J2) of both nematode species. P. rockii extracts were more effective than P. suffruticosa extracts for decreasing M. incognita hatch and J2 viability. In greenhouse trials with soybean (Glycine max 'Essex'), powdered C. oleifera cake applied as a soil amendment suppressed H. glycines cysts/g root by up to 66% compared with nonamended controls. These results indicate that the extracts and cake contain compounds active against H. glycines and M. incognita, with activity varying between the two Paeonia species. C. oleifera tea seed cake, and constituents of the cake or of P. rockii, are candidates for further studies on management of these nematodes.


Assuntos
Camellia , Paeonia , Extratos Vegetais , Tylenchoidea , Animais , Antinematódeos/farmacologia , Camellia/química , Paeonia/química , Extratos Vegetais/farmacologia , Sementes/química , Tylenchoidea/efeitos dos fármacos
10.
Plant Dis ; 103(9): 2392-2396, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31318644

RESUMO

California grows approximately 80% of the U.S. carrot production. The primary production challenges derive from root-knot nematodes (Meloidogyne spp.). Between 2013 and 2016, we evaluated three novel fluorinated nonfumigant nematicides in five field trials. Fluensulfone, fluopyram, and fluazaindolizine were applied as product-ready formulations at various rates, dates, and formulations. They were rated for their efficacy against the Southern root-knot nematode (M. incognita), their ability to mitigate nematode-caused crop damage, and potential to produce marketable carrot yield under high disease pressure. All trials were conducted in randomized complete block designs in M. incognita-infested, sandy-loam fields. Soil population of M. incognita at seeding and harvest, midseason plant vigor and fibrous root galling, harvest taproot galling, and marketable carrot yield were analyzed by ANOVA. Midseason gall ratings were indicative of disease ratings at harvest. All fluazaindolizine and fluensulfone treatments reduced at-harvest galling compared with the untreated controls. Fluopyram resulted in less galling but did not sufficiently protect the lower part of the taproot. Overall, fluazaindolizine at 2.24 kg/ha resulted in the most consistent and highest marketable carrot yield, followed by fluensulfone at 2.95 kg/ha. Both fluazaindolizine and fluensulfone will likely provide effective and target-selective crop protection against root-knot nematodes in fresh carrot production.


Assuntos
Antinematódeos , Daucus carota , Tylenchoidea , Animais , Antinematódeos/farmacologia , California , Daucus carota/parasitologia , Solo , Tylenchoidea/efeitos dos fármacos , Tylenchoidea/fisiologia
11.
Poult Sci ; 98(11): 5412-5415, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31328783

RESUMO

An important factor in efficient production of poultry is management of parasites. Ascaridia dissimilis is the most prevalent small intestinal nematode parasite of turkeys with up to 100% of flocks infected. High worm burdens can cause necrotic enteritis leading to high mortality in flocks. Recently, we were made aware of multiple cases where high burdens were seen at slaughter despite the administration of anthelmintics at frequent intervals, suggesting that resistance may have evolved in A. dissimilis. To address this issue, we obtained eggs of A. dissimilis from 4 commercial turkey farms and performed controlled efficacy tests to determine if fenbendazole resistance was present. Three farms had histories of frequent use of fenbendazole and worms found at slaughter, suggesting they may have resistance, and one was an organic farm where we had no additional history other than the farm had transitioned to organic production a few years earlier. For each worm isolate there were 2 treated and 2 untreated groups containing 9 birds each, with all groups being replicated in 2 separate rooms. Birds were infected with approximately 200 infective eggs, and treated groups received fenbendazole in the water (SafeGuard Aquasol, 1 mg/kg) for 5 consecutive days starting on day 24 post-infection. One week after the last treatment birds were necropsied, intestinal contents were collected and worms enumerated. Three of the four isolates demonstrated greater than 99% efficacy, indicating they were fully susceptible to fenbendazole. However, the fourth isolate demonstrated a significantly reduced efficacy of 63.89%, indicating the presence of resistance. Interestingly, this was the organic farm, whereas the 3 farms with "suspected" resistance all turned out to be fully susceptible. Given that 1 randomly acquired isolate of A. dissimilis, out of 4 tested, demonstrated resistance in this study, fenbendazole resistance may be a much larger problem on turkey farms than is currently recognized. Additional studies are needed to determine the prevalence of resistance, as well as the economic impact that resistant A. dissimilis have on turkey production.


Assuntos
Antinematódeos/farmacologia , Ascaridia/efeitos dos fármacos , Resistência a Medicamentos , Fenbendazol/farmacologia , Perus , Animais , Ascaridíase/parasitologia , Ascaridíase/veterinária , Feminino , Masculino , Doenças das Aves Domésticas/parasitologia
12.
Plant Physiol Biochem ; 142: 202-210, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31302409

RESUMO

Activation of induced plant resistance to control pests and diseases is regaining attention in the current climate where chemical pesticides are being progressively banned. Formulations of chitosan oligomers (COS) and pectin-derived oligogalacturonides (OGA), COS-OGA, have previously been described to induce resistance against fungal diseases in different crop plants. Here, we investigated their potential and mode-of-action as preventive measures to control root-knot nematode Meloidogyne graminicola infection in rice. The results show a significant reduction in root-galling and nematode development in rice plants that were treated through foliar application with the COS-OGA formulations FytoSol® and FytoSave® 24 h before nematode inoculation. Hormone measurements, gene expression analyses, corroborated by treatments on salicylic acid (SA) and jasmonic acid (JA)-mutants indicated that the systemic COS-OGA induced defense mechanism against nematodes is not based on SA or JA activation. However, phenylalanine ammonia lyase (PAL) gene expression in roots as well as enzymatic PAL activity in the shoots were significantly induced 24 h after foliar COS-OGA spraying in comparison with untreated plants. COS-OGA-induced systemic defense was abolished in the rice OsPAL4-mutant, demonstrating that COS-OGA-induced defense is dependent on OsPAL4 activation in rice plants.


Assuntos
Antinematódeos/farmacologia , Quitosana/metabolismo , Oryza/parasitologia , Doenças das Plantas/parasitologia , Raízes de Plantas/parasitologia , Tumores de Planta/parasitologia , Tylenchoidea , Animais , Oryza/metabolismo , Fenóis/metabolismo , Doenças das Plantas/prevenção & controle , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/metabolismo , Propanóis/metabolismo
13.
Biosci Biotechnol Biochem ; 83(12): 2194-2197, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31357905

RESUMO

The nematocidal activities of the fatty acid esters of d-allose were examined using the larvae of C. elegans. Among the fatty acid esters, 6-O-octanoyl-d-allose (3) showed significant activity. 6-O-octanoyl-d-glucose (5) showed no activity, indicating that the D-allose moiety is essential for the nematocidal activity of 3. A nonhydrolyzable alkoxy analog 6-O-octyl-d-allose (6) also showed activity equivalent to that of 3.


Assuntos
Antinematódeos/farmacologia , Caenorhabditis elegans/crescimento & desenvolvimento , Glucose/farmacologia , Larva/efeitos dos fármacos , Animais , Glucose/química
14.
J Exp Clin Cancer Res ; 38(1): 293, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31287013

RESUMO

BACKGROUND: Signal transducer and activator of transcription 3 (STAT3) is an oncogene, which upregulates in approximately 70% of human cancers. Autophagy is an evolutionarily conserved process which maintains cellular homeostasis and eliminates damaged cellular components. Moreover, the STAT3 signaling pathway, which may be triggered by cancer cells, has been implicated in the autophagic process. METHODS: In this study, we found that the anthelmintic flubendazole exerts potent antitumor activity in three human colorectal cancer (CRC) cell lines and in the nude mouse model. The inhibition of cell proliferation in vitro by flubendazole was evaluated using a clonogenic assay and the MTT assay. Western blot analysis, flow cytometry analysis, siRNA growth experiment and cytoplasmic and nuclear protein extraction were used to investigate the mechanisms of inhibiting STAT3 signaling and activation of autophagy induced by flubendazole. Additionally, the expression of STAT3 and mTOR was analyzed in paired colorectal cancer and normal tissues collected from clinical patients. RESULTS: Flubendazole blocked the IL6-induced nuclear translocation of STAT3, which led to inhibition of the transcription of STAT3 target genes, such as MCL1, VEGF and BIRC5. In addition, flubendazole also reduced the expression of P-mTOR, P62, BCL2, and upregulated Beclin1 and LC3-I/II, which are major autophagy-related genes. These processes induced potent cell apoptosis in CRC cells. In addition, flubendazole displayed a synergistic effect with the chemotherapeutic agent 5-fluorouracil in the treatment of CRC. CONCLUSIONS: Taken together, these results indicate that flubendazole exerts antitumor activities by blocking STAT3 signaling and inevitably affects the autophagy pathway. Flubendazole maybe a novel anticancer drug and offers a distinctive therapeutic strategy in neoadjuvant chemotherapy of CRC.


Assuntos
Antinematódeos/uso terapêutico , Autofagia/efeitos dos fármacos , Mebendazol/análogos & derivados , Fator de Transcrição STAT3/antagonistas & inibidores , Animais , Antinematódeos/farmacologia , Feminino , Humanos , Mebendazol/farmacologia , Mebendazol/uso terapêutico , Camundongos , Camundongos Nus , Transfecção
15.
J Fish Dis ; 42(10): 1351-1357, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31309582

RESUMO

Pseudocapillaria tomentosa is a pathogenic nematode parasite, causing emaciation and severe inflammatory lesions in the intestines in zebrafish Danio rerio (Hamilton 1822). Emamectin benzoate is commercially available analogue of ivermectin used for treating salmon for sea lice, under the brand name SLICE® , and we have used this for treating zebrafish with the P. tomentosa. Here, SLICE® , 0.2 per cent active emamectin benzoate, was used for oral treatments at 0.35 mg emamectin benzoate/kg fish/day for 14 days starting at 7 days post-exposure (dpe). Another experiment entailed initiating treatment during clinical disease (starting at 28 dpe). Early treatment was very effective, but delaying treatment was less so, presumably due to inappetence in clinically affected fish. We evaluated emamectin benzoate delivered in water, using Lice-Solve™ (mectinsol; 1.4% active emamectin benzoate) in two experiments. Application of four 24-hr treatments, space over 7 days was initiated at 28 dpe at either 0.168 or 0.56 mg emamectin benzoate/L/bath, and both treatments completely eradicated infections. This was 3 or 10 times manufacture's recommended dose, but was not associated with clinical or histological side effects.


Assuntos
Antinematódeos/farmacologia , Infecções por Enoplida/veterinária , Enoplídios/efeitos dos fármacos , Doenças dos Peixes/tratamento farmacológico , Ivermectina/análogos & derivados , Peixe-Zebra , Animais , Relação Dose-Resposta a Droga , Infecções por Enoplida/tratamento farmacológico , Feminino , Ivermectina/farmacologia , Masculino
16.
J Microbiol Biotechnol ; 29(7): 1117-1123, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31216609

RESUMO

Control of pine wilt disease, which is caused by pine wilt nematode, Bursaphelenchus xylophilus, is heavily dependent on the use of chemicals such as abamectin. Although such chemicals are highly effective, demands for alternatives that are derived preferentially from natural sources, are increasing out of environmental concerns. One of the challenges to discovery of alternative control agents is lack of fast and efficient screening method that can be used in high-throughput manner. Here we described the development of colorimetric assay for the rapid and accurate screening of candidate nematicidal compounds/biologics targeting B. xylophilus. Contrary to the conventional method, which relies on laborious visual inspection and counting of nematode population under microscope, our method utilizes a redox dye that changes its color in response to metabolic activity of nematode population in a given sample. In this work, we optimized parameters of our colorimetric assay including number of nematodes and amount of redox dye, and tested applicability of our assay for screening of chemicals and biologics. We demonstrated that our colorimetric assay can applied to rapid and accurate quantification of nematode viability/mortality in a nematode population treated with candidate chemicals/biologics. Application of our method would facilitate high-throughput endeavors aiming at finding environment-friendly control agents for deadly disease of pine trees.


Assuntos
Bioensaio/métodos , Nematoides/fisiologia , Pinus , Doenças das Plantas/parasitologia , Animais , Antinematódeos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Colorimetria , Indicadores e Reagentes/metabolismo , Nematoides/metabolismo , Oxazinas/metabolismo , Oxirredução , Tylenchida/metabolismo , Tylenchida/fisiologia , Xantenos/metabolismo
17.
Molecules ; 24(9)2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31058826

RESUMO

Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38-52% in root length and 50-60% in leaf length of L. perenne, but no effects were observed on S. lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management.


Assuntos
Antinematódeos/farmacologia , Eugenia/química , Ácidos Graxos/farmacologia , Inseticidas/farmacologia , Animais , Antinematódeos/química , Cromadoria/efeitos dos fármacos , Ácidos Graxos/química , Cromatografia Gasosa-Espectrometria de Massas , Hemípteros/efeitos dos fármacos , Inseticidas/química , Lolium/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Estrutura Molecular , Controle de Pragas , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento
18.
J Agric Food Chem ; 67(22): 6160-6168, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31099574

RESUMO

Naturally occurring thiophenes possess excellent nematicidal and fungicidal activities. However, thiophenes often have limited application in soil due to their light-dependent toxicity given the living and reproductive condition of soil-borne pathogens. In this study, six new (1-6) and six known thiophenes (7-12) were isolated from Echinops grijsii. Compounds 1-2, 4-5, 8-9, 11 , and 12 showed stronger nematicidal activity against Meloidogyne incognita than commercial nematicide abamectin. 4-10 were demonstrated as nonphototoxic thiophenes. Among these, 4 and 8 were the most potent thiophenes (LC50 values 2.57 and 0.91 µg/mL in light, 1.80 and 0.86 µg/mL in dark, respectively) against M. incognita. SAR revealed that thiophene skeleton was essential for nematicidal activity, while disubstituted groups were helpful for nonphototoxicity. Although an increased number of acetylenes improved activity, it decreased nonphototoxicity. Acyl groups could suppress the effects of light on activity, with the level of inhibitory effects depending on its number and chain length, while chlorine played important roles in promoting activity. Additionally, compounds 1-2, 4-5, 7, 8, and 10 displayed antifungal activity against six soil-borne fungi in various degrees. The discovery of nonphototoxic thiophenes and elucidation of SAR provide important information for the exploitation and utilization of thiophenes in the integrative management regarding disease complexes caused by the combination of root-knot nematode and soil-borne fungi.


Assuntos
Antinematódeos/química , Echinops (Planta)/química , Fungicidas Industriais/química , Extratos Vegetais/química , Tiofenos/química , Animais , Antinematódeos/isolamento & purificação , Antinematódeos/farmacologia , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/isolamento & purificação , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Raízes de Plantas/microbiologia , Raízes de Plantas/parasitologia , Microbiologia do Solo , Relação Estrutura-Atividade , Tiofenos/isolamento & purificação , Tiofenos/farmacologia , Tylenchoidea/efeitos dos fármacos , Tylenchoidea/crescimento & desenvolvimento
19.
Phytopathology ; 109(9): 1605-1613, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31033406

RESUMO

Meloidogyne species are one of the most important groups of plant-parasitic nematodes globally because of their ability to damage most cultivated plants. Although they are widespread and economically important, there are limited control measures to combat these nematodes. New nonfumigant nematicides have been discovered that have the potential to be widely utilized for the management of plant-parasitic nematodes. Because of the longer half-lives in soil and lower toxicity of new nematicides compared with traditional fumigant and nonfumigant nematicides, understanding how nematodes respond to sublethal doses of nematicides is imperative to understanding whether nematicide resistance has the potential to develop. Characterizing responses of nematodes to sublethal doses will provide the foundation for future work, such as gene expression studies. In this study, the nematicides oxamyl (Vydate), fluazaindolizine (Salibro), fluensulfone (Nimitz), and fluopyram (Velum), were evaluated to understand how sublethal doses affect the fecundity and mobility of Meloidogyne incognita second-stage juveniles (J2). Using a microwell assay system, dose-response curves for each nematicide were established for M. incognita J2. Fluopyram was the most toxic nematicide, with effective doses up to 230 times lower than that of other nematicides. The other nematicides had predicted ED50 values (effective doses that resulted in 50% of the population becoming inactive) of 89.4, 131.7, and 180.6 ppm for oxamyl, fluensulfone, and fluazaindolizine, respectively. The 24-h ED50 of each nematicide was then used in both motility and infectivity assays. The motility and activity of M. incognita J2 exposed to ED50 doses of fluazaindolizine and fluensulfone was significantly reduced, with nematodes initially being motile but eventually becoming inactive. However, the motility of M. incognita J2 exposed to ED50 doses of fluopyram and oxamyl was not different from a water control. In a pot assay, M. incognita J2 exposed to ED50 doses of fluazaindolizine, oxamyl, and fluensulfone were unable to reproduce on tomato, with reproduction factors (RF = final population density/initial population density) of 0 to 0.03. Fluopyram did not reduce reproduction of M. incognita, with a mean RF of 38.7 ± 4.5, which was similar to the RF of 46.3 ± 4.6 for the water control. This study is the first comprehensive evaluation of M. incognita activity, motility, and fecundity after exposure to the traditional nematicide, oxamyl, as well as three new nematicides, fluazaindolizine, fluopyram, and fluensulfone.


Assuntos
Lycopersicon esculentum , Praguicidas , Tylenchoidea , Animais , Antinematódeos/farmacologia , Doenças das Plantas , Tylenchoidea/efeitos dos fármacos
20.
Mar Drugs ; 17(4)2019 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-30959907

RESUMO

Lymphangiogenesis is an important biological process associated with cancer metastasis. The development of new drugs that block lymphangiogenesis represents a promising therapeutic strategy. Marine fungus-derived compound phomaketide A, isolated from the fermented broth of Phoma sp. NTOU4195, has been reported to exhibit anti-angiogenic and anti-inflammatory effects. However, its anti-lymphangiogenic activity has not been clarified to date. In this study, we showed that phomaketide A inhibited cell growth, migration, and tube formation of lymphatic endothelial cells (LECs) without an evidence of cytotoxicity. Mechanistic investigations revealed that phomaketide A reduced LECs-induced lymphangiogenesis via vascular endothelial growth factor receptor-3 (VEGFR-3), protein kinase Cδ (PKCδ), and endothelial nitric oxide synthase (eNOS) signalings. Furthermore, human proteome array analysis indicated that phomaketide A significantly enhanced the protein levels of various protease inhibitors, including cystatin A, serpin B6, tissue factor pathway inhibitor (TFPI), and tissue inhibitor matrix metalloproteinase 1 (TIMP-1). Importantly, phomaketide A impeded tumor growth and lymphangiogenesis by decreasing the expression of LYVE-1, a specific marker for lymphatic vessels, in tumor xenograft animal model. These results suggest that phomaketide A may impair lymphangiogenesis by suppressing VEGFR-3, PKCδ, and eNOS signaling cascades, while simultaneously activating protease inhibitors in human LECs. We document for the first time that phomaketide A inhibits lymphangiogenesis both in vitro and in vivo, which suggests that this natural product could potentially treat cancer metastasis.


Assuntos
Inibidores da Angiogênese/farmacologia , Antinematódeos/farmacologia , Ascomicetos/química , Linfangiogênese/efeitos dos fármacos , Policetídeos/farmacologia , Células A549 , Inibidores da Angiogênese/isolamento & purificação , Inibidores da Angiogênese/uso terapêutico , Animais , Antinematódeos/isolamento & purificação , Antinematódeos/uso terapêutico , Organismos Aquáticos/química , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Humanos , Metástase Linfática , Vasos Linfáticos/citologia , Masculino , Camundongos , Camundongos Nus , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Óxido Nítrico Sintase Tipo III/metabolismo , Policetídeos/isolamento & purificação , Policetídeos/uso terapêutico , Proteína Quinase C-delta/metabolismo , Transdução de Sinais/efeitos dos fármacos , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA