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1.
Toxins (Basel) ; 12(11)2020 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-33137918

RESUMO

Alkaloids are important metabolites found across a variety of organisms with diverse ecological functions. Of particular interest are alkaloids found in ants, organisms well known for dominating the ecosystems they dwell in. Within ants, alkaloids are found in venom and function as potent weapons against heterospecific species. However, research is often limited to pest species or species with parasitic lifestyles and thus fails to address the broader ecological function of ant venom alkaloids. Here we describe a new species of free-living Megalomyrmex ant: Megalomyrmex peetersi sp. n. In addition, we identify its singular venom alkaloid (trans-2-butyl-5-heptylpyrrolidine) and elucidate the antibiotic and insecticidal functions of its venom. Our results show that Megalomyrmex peetersi sp. n. venom is an effective antibiotic and insecticide. These results are comparable to venom alkaloids found in other ant species, such as Solenopsis invicta. This research provides great insight into venom alkaloid function, and it is the first study to explore these ideas in the Megalomyrmex system.


Assuntos
Alcaloides/toxicidade , Venenos de Formiga/toxicidade , Antibacterianos/toxicidade , Formigas , Inseticidas/toxicidade , Alcaloides/química , Animais , Venenos de Formiga/química , Antibacterianos/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Feminino , Inseticidas/química , Isópteros/efeitos dos fármacos , Dose Letal Mediana , Masculino
2.
J Agric Food Chem ; 68(16): 4687-4698, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32251592

RESUMO

The goal of this study was to perform in silico identification of bioinsecticidal potential of 42 monoterpenes against Drosophila melanogaster and Reticulitermes chinensis Snyder. Quantitative structure-activity relationship (QSAR) modeling was performed for both organisms, while docking and molecular dynamics were used only for Drosophila melanogaster. Neryl acetate has the lowest interaction energy (-87 kcal/mol) against active site of acetylcholinesterase, which is comparable to the ones of methiocarb and pirimicarb (-90 kcal/mol) and reported PDB binder 9-(3-iodobenzylamino)-1,2,3,4-tetrahydroacridine (-112.67 kcal/mol). Interaction stability was verified by molecular dynamics simulations and showed that the stability of ACHE active site complexes with three selected terpenes is comparable to the one of the pirimicarb and methiocarb. Overall, our results suggest that pulegone, citronellal, carvacrol, linalyl acetate, neryl acetate, citronellyl acetate, and geranyl acetate may be considered as a potential pesticide candidates.


Assuntos
Drosophila melanogaster/efeitos dos fármacos , Inseticidas/química , Inseticidas/farmacologia , Isópteros/efeitos dos fármacos , Monoterpenos/química , Monoterpenos/farmacologia , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Animais , Drosophila melanogaster/química , Drosophila melanogaster/enzimologia , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Isópteros/química , Isópteros/enzimologia , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Relação Quantitativa Estrutura-Atividade
3.
PLoS One ; 15(3): e0230664, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32208460

RESUMO

Recent empirical evidence suggests that herbicides have damaging effects on non-target organisms in both natural and semi-natural ecosystems. The African mound building termite, Macrotermes bellicosus, is an important beneficial insect that functions as an ecosystem engineer due to its role in the breakdown of dead and decaying materials. Here, we examined the effects of 2,4-D amine salt (2,4-D) and atrazine based herbicides viz. Vestamine® and Ultrazine® on the survival and locomotion response of M. bellicosus. Worker termites were treated with a range of concentrations of Vestamine® (the recommended concentration: 6.25 ml per 500 ml of water, 0.25- and 0.5-fold below the recommended concentration and distilled water as control) and Ultrazine® (the recommended concentration: 3.75 ml per 500 ml of water, 0.25-, 0.5-, 2.0- and 4-fold of the recommended concentration and distilled water as control) for 24 hours for the mortality test, and allowed to run for 15 seconds for the locomotion trial. All concentrations of both Vestamine® and Ultrazine® were highly toxic to worker termites and mortality increased as the concentration and time after treatment increased. For both herbicides, concentrations far less than the recommended rates caused 100% mortality. The speed of termites was significantly influenced by both Vestamine® and Ultrazine® as termites exposed to all tested concentrations of the herbicides exhibited reduced running speed than the control. These findings suggest that beneficial insects, especially M. bellicosus may experience high mortality (up to 100%) and reduced mobility if they are sprayed upon or come in contact with plant materials that have been freshly sprayed with (less or more than) the recommended concentrations of Vestamine® and Ultrazine®. The findings of our study calls for the reassessment of the usage of 2,4-D and atrazine based herbicides in weed control in termite and other beneficial insect populated habitats.


Assuntos
Ácido 2,4-Diclorofenoxiacético/farmacologia , Atrazina/farmacologia , Herbicidas/farmacologia , Isópteros/fisiologia , Locomoção/efeitos dos fármacos , Animais , Ecossistema , Isópteros/efeitos dos fármacos
5.
J Econ Entomol ; 112(1): 290-299, 2019 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-30346605

RESUMO

Moisture conditions of food and soil are essential for the survival and foraging activities of subterranean termites. Polyacrylamide/attapulgite composite is a water-retaining agent that has been applied to increase moisture of agricultural soils. We hypothesize that polyacrylamide/attapulgite composite may increase the moisture of bait matrixes and soil surrounding baiting containers and therefore attract termites and increase their foraging activities. In the present study, aggregation and feeding preferences, survivorship, body water percentage, and wood consumption of Formosan subterranean termites, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), were investigated when responding to polyacrylamide/attapulgite composite that was buried within soil (substrate) or filled in the void volume of baiting containers. Two-choice tests showed that termites consumed significantly more wood when polyacrylamide/attapulgite composite was buried within dry soil (27%-moisture) than the controls (no polyacrylamide/attapulgite composite was provided). However, polyacrylamide/attapulgite composite buried within wet soil (54%-moisture) did not significantly affect foraging behaviors of termites. Multiple-choice tests showed no aggregation or feeding preference of termites in the baiting containers filled with polyacrylamide/attapulgite composite compared with the soil-filled or unfilled ones, whenever the substrate was dry or wet. No-choice tests showed that the presence of polyacrylamide/attapulgite composite (buried within soil or filled in baiting containers) significantly increased wood consumption and body water percentage of termites as well as wood moisture under dry-substrate conditions. Our studies suggest that burying polyacrylamide/attapulgite composite within dry soil may enhance foraging activities of termites, but filling the bait stations with polyacrylamide/attapulgite composite may not effectively attract termites.


Assuntos
Resinas Acrílicas/farmacologia , Comportamento Animal/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Compostos de Magnésio/farmacologia , Compostos de Silício/farmacologia , Animais , Solo
6.
Environ Sci Pollut Res Int ; 25(28): 28102-28108, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30069778

RESUMO

The effects of diatomaceous earth (DE) on the penetrating behavior, tunneling behavior, mortality, and body surface characteristics of the subterranean termite Reticulitermes chinensis were investigated in this study. Our results show that the workers of R. chinensis were able to penetrate 1- and 2-mm layers of dry DE but not 3-mm layers. After treatment with dry DE for 6 h, the mortality of termites reached 100%, which was significantly higher than in the treatment with DE with a 10 and 25% moisture content and treatment with sand of three different moisture contents. The tunneling distances of workers in DE with 10, 25, and 50% moisture contents were all significantly shorter than those in sand with the same moisture contents (10, 25, and 50%), indicating that DE has a good suppressing effect on the tunneling behavior of workers. After treatment with dry DE for different times (1, 3, and 6 h), many DE particles adhered to the bodies of workers, whereas no particles adhered to the body of workers in the case of treatment with dry sand. The treatment with dry DE for 6 h resulted in the death of all workers, which presented conspicuous abdominal shrinkage, whereas workers treated with sand had no significant mortality and no obvious abdominal shrinkage. In summary, we suggest that dry DE has ideal insecticidal activity against the subterranean termite R. chinensis and can be further exploited for controlling termites inside houses.


Assuntos
Terra de Diatomáceas/toxicidade , Inseticidas/toxicidade , Isópteros/efeitos dos fármacos , Animais , Isópteros/fisiologia , Dióxido de Silício
7.
Int J Biol Macromol ; 118(Pt B): 2296-2306, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30030073

RESUMO

Cassia grandis trypsin inhibitor (CgTI) is a novel plant serine proteinase inhibitor. This study sets out to purify a thermostable inhibitor from the seeds of Cassia grandis and to provide biochemical information about a novel peptide belonging to the Kunitz family. Moreover, toxicity assays against Artemia, Aedes aegypti larvae-L4 and Nasutitermes corniger are evaluated. The purification process was performed using acetone precipitation, Trypsin-Sepharose-CL4B and Superdex-G75. The inhibitor showed an apparent molecular mass of around 19.8 kDa on Superdex-G75 gel filtration, and a mass of around 19.0 kDa visualized by SDS-PAGE under reducing conditions, and it also showed the protein consists of two polypeptide chains. N-terminal sequencing by Edman's degradation of 16 residues revealed a sequence of amino acids SVVLDTSGEPIRNGGG. 2D-electrophoresis identified a pI value of 6.3 and a 1:1 stoichiometric ratio was noted during CgTI-trypsin complex formation. The inhibitor retained the inhibitory activity over a broad range of pH (5-10) and showed thermostable activity at temperatures 30-80 °C. Furthermore, in vivo assays showed no lethality effect against Artemia and Aedes aegypti larvae, but mortality against Nasutitermes corniger with termiticidal activity LC50 of 0.685 mg/mL on workers and 0.765 mg/mL on soldiers. Preliminary investigations of CgTI revealed it to be a promising biotechnological and biomedical candidate.


Assuntos
Cassia/química , Isópteros/efeitos dos fármacos , Proteínas de Plantas/farmacologia , Sementes/química , Inibidores da Tripsina/isolamento & purificação , Inibidores da Tripsina/farmacologia , Sequência de Aminoácidos , Animais , Bioensaio , Biotecnologia , Estabilidade Enzimática/efeitos dos fármacos , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Temperatura , Inibidores da Tripsina/química
8.
Microb Pathog ; 123: 52-59, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29959038

RESUMO

The entomopathogenic fungus Metarhizium anisopliae is widely used as biocontrol agent against many insect pests. In the present study, the potential isolate of M. anisopliae TK29 was isolated from the agricultural soils in Thekkady, India. The taxonomic identity of the isolate was confirmed based on its morphology and 18S rDNA gene sequence homology. Phylogenetic analysis confirmed that the isolated strains were related to the same species. A potential isolate (TK29) was optimized for mass cultivation and conidial spore production was enhanced using three different raw substrates (Rice, Maize, black gram) by solid-state fermentation. The results showed higher conidial spore yield from rice (2.6 ±â€¯0.32%) compared to black gram (2.1 ±â€¯0.28%) and maize (1.9 ±â€¯0.23%) substrates. Dry green conidia were applied against Formosan subterranean termite, Coptotermes formosanus at three different concentrations (1 × 106, 1 × 107, and 1 × 108 conidia/ml-1). The highest mortality rate was obtained from 1 × 108 conidia/ml-1 at 120 h post-treatment. Our study indicated that M. anisopliae TK29 had desirable attributes for the development of a mycoinsecticide against C. formosanus.


Assuntos
Antibiose/fisiologia , Agentes de Controle Biológico/farmacologia , Isópteros/efeitos dos fármacos , Metarhizium/isolamento & purificação , Metarhizium/metabolismo , Controle Biológico de Vetores/métodos , Animais , Índia , Metarhizium/classificação , RNA Ribossômico 18S/genética , Microbiologia do Solo , Esporos Fúngicos/crescimento & desenvolvimento
9.
Genetics ; 209(4): 1225-1234, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29934338

RESUMO

Sterile castes are a defining criterion of eusociality; investigating their evolutionary origins can critically advance theory. In termites, the soldier caste is regarded as the first acquired permanently sterile caste. Previous studies showed that juvenile hormone (JH) is the primary factor inducing soldier differentiation, and treatment of workers with artificial JH can generate presoldier differentiation. It follows that a shift from a typical hemimetabolous JH response might be required for soldier formation during the course of termite evolution within the cockroach clade. To address this possibility, analysis of the role of JH and its signaling pathway was performed in the termite Zootermopsis nevadensis and compared with the wood roach Cryptocercus punctulatus, a member of the sister group of termites. Treatment with a JH analog (JHA) induced a nymphal molt in C. punctulatus RNA interference (RNAi) of JH receptor Methoprene tolerant (Met) was then performed, and it inhibited the presoldier molt in Z. nevadensis and the nymphal molt in C. punctulatus Knockdown of Met in both species inhibited expression of 20-hydroxyecdysone (20E; the active form of ecdysone) synthesis genes. However, in Z. nevadensis, several 20E signaling genes were specifically inhibited by Met RNAi. Consequently, RNAi of these genes were performed in JHA-treated termite individuals. Knockdown of 20E signaling and nuclear receptor gene, Hormone receptor 39 (HR39/FTZ-F1ß) resulted in newly molted individuals with normal worker phenotypes. This is the first report of the JH-Met signaling feature in termites and Cryptocercus JH-dependent molting activation is shared by both taxa and mediation between JH receptor and 20E signalings for soldier morphogenesis is specific to termites.


Assuntos
Baratas/crescimento & desenvolvimento , Perfilação da Expressão Gênica/métodos , Proteínas de Insetos/genética , Isópteros/crescimento & desenvolvimento , Animais , Comportamento Animal/efeitos dos fármacos , Baratas/efeitos dos fármacos , Baratas/genética , Ecdisterona/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Isópteros/genética , Hormônios Juvenis/farmacologia , Muda/efeitos dos fármacos , Comportamento Social
10.
Pak J Pharm Sci ; 31(2): 371-377, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29618423

RESUMO

The current study focused on the pharmacological activities of Justicia adhatoda; including antibacterial, antifungal, phytotoxic, cytotoxic, haemagglutination, insecticidal, in vitro antiglycation, DPPH antioxidant and anti-termite. The crude methanolic extract (Crd. Met. Ext) showed 46.4 % antibacterial activity against M. morganii while the n-hexane fraction showed good (71.4%) and moderate (55.1%) activity against M. morganii and A. baumannii respectively. The EtOAc and aqueous fractions, in most of the cases, showed low to no activity against the selected bacterial pathogens, against A. niger, T. harzianum, A. parasiticus and V. dahliae. The Crd. Met. Ext and fractions showed low activity, against P. notatum and P. digitatum, Crd. Met. Ext. and all fractions were inactive. The percent growth regulation, in case of phytotoxic activity, by Crd. Met. Ext was 25 and 16.6, n-hexane fraction 16.6, 16.6 and 0, CHCl3 25, 8.33 and 0 % and EtOAc fractions 8.33, 8.33 and 0% at 1000 and 100 and 10µg/ml respectively. The aqueous fraction was inactive at all the test concentrations. The results of brine shrimp cytotoxic activity for Crd. Met. Ext was 13.33% and n-hexane fraction 20% at 1000, µg/ml respectively. All of the other fractions showed low to no activity at different test concentrations. All of the test samples were inactive against RBC's of the blood groups at all concentration indicating that the selected plant lack phytolectins and haemagglutination activity. The Crd. Met. Ext and various fraction showed low activity against the test insects i.e. C. pulicaria, C. chinensis and T. castaneum. The absorbance value of plant extract for anti-glycation activity at various concentration were: 0.08, 0.067, 0.053 and 0.04 in comparison with Aminoguanidine 0.04, 0.035, 0.03 and 0.02 respectively at 10, 50, 90 and 130µl. The DPPH radical scavenging activities were proportional to the concentration of the fractions, as the concentration of these increased, the percent scavenging activity also increased. The CHCl3 and EtOAc fractions killed all the termites in 24 hours while Crd. Met. Ext, n-hexane and aqueous fractions took 2-3 days.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Inseticidas/farmacologia , Justicia/química , Animais , Artemia/efeitos dos fármacos , Hemaglutinação/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Extratos Vegetais/farmacologia , Plantas Medicinais/química
11.
J Econ Entomol ; 111(2): 808-816, 2018 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-29471445

RESUMO

Previous studies showed that many wood-rotting fungi were attractive to termites; however, little attention has been paid to the relationship between termites and soil fungus. In the present study, different designs of two-choice tests were conducted to investigate the behaviors of two subterranean termites, Coptotermes formosanus Shiraki (wood-feeding lower termites) and Odontotermes formosanus (Shiraki) (fungus-growing higher termites), in response to soil (or sand) treated with the commercial conidial formulations of Trichoderma harzianum Rifai (BioWorks) and Trichoderma viride Pers. ex Fries (Shuiguxin). The short-term (1 d) choice tests showed no significant difference in termite aggregation (C. formosanus and O. formosanus) between treated and untreated soil, regardless of Trichoderma species and concentrations. However, in the long-term choice tests, C. formosanus consumed significantly more wood in the chambers containing soil treated with the conidial formulation of T. viride (1 × 108 conidia/g) than that containing untreated soil. The tunneling choice tests showed that sand treated with T. viride (1 × 106 or 1 × 108 conidia/g) or T. harzianum (1 × 106 conidia/g) significantly increased the tunneling activities of C. formosanus. However, sand treated with T. viride (1 × 106 or 1 × 108 conidia/g) had a repellent effect on O. formosanus. Our study showed that the two subterranean termites behaved differently when responding to the conidial formulations of Trichoderma.


Assuntos
Repelentes de Insetos , Isópteros , Feromônios , Solo , Trichoderma/química , Animais , Dieta , Repelentes de Insetos/farmacologia , Isópteros/efeitos dos fármacos , Feromônios/farmacologia , Especificidade da Espécie , Esporos Fúngicos/química
12.
Pest Manag Sci ; 74(7): 1593-1599, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29297969

RESUMO

BACKGROUND: Lectins, carbohydrate-binding proteins, from the bark (MuBL) and leaf (MuLL) of Myracrodruon urundeuva are termiticidal agents against Nasutitermes corniger workers and have been shown to induce oxidative stress and cell death in the midgut of these insects. In this study, we investigated the binding targets of MuBL and MuLL in the gut of N. corniger workers by determining the effects of these lectins on the activity of digestive enzymes. In addition, we used mass spectrometry to identify peptides from gut proteins that adsorbed to MuBL-Sepharose and MuLL-Sepharose columns. RESULTS: Exoglucanase activity was neutralized in the presence of MuBL and stimulated by MuLL. α-l-Arabinofuranosidase activity was not affected by MuBL but was inhibited by MuLL. Both lectins stimulated α-amylase activity and inhibited protease and trypsin-like activities. Peptides with homology to apolipophorin, trypsin-like enzyme, and ABC transporter substrate-binding protein were detected from proteins that adsorbed to MuBL-Sepharose, while peptides from proteins that bound to MuLL-Sepharose shared homology with apolipophorin. CONCLUSION: This study revealed that digestive enzymes and transport proteins found in worker guts can be recognized by MuBL and MuLL. Thus, the mechanism of their termiticidal activity may involve changes in the digestion and absorption of nutrients. © 2018 Society of Chemical Industry.


Assuntos
Anacardiaceae/química , Inseticidas/metabolismo , Isópteros/efeitos dos fármacos , Lectinas de Plantas/metabolismo , Animais , Sistema Digestório/efeitos dos fármacos , Sistema Digestório/enzimologia , Isópteros/enzimologia , Casca de Planta/química , Folhas de Planta/química , Lectinas de Plantas/administração & dosagem
13.
Ecotoxicol Environ Saf ; 145: 436-441, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28778042

RESUMO

The drywood termite Cryptotermes brevis (Walker, 1853) (Kalotermitidae) is one of the most important wood structural pest in the world. Substances from the secondary metabolism of plants (e.g., essential oils) have been considered an environmentally safer form of control for urban pests, such as termites. In the present study, we analyzed the lethal and sub-lethal effects of essential oil of Lippia sidoides and its major components on C. brevis pseudergates in two routes of exposure (contact and fumigation). The essential oil of L. sidoides and thymol were more toxic to C. brevis pseudergates when applied by contact (LD50 = 9.33 and 8.20µgmg-1, respectively) and by fumigation (LC50 = 9.10 and 23.6µLL-1, respectively). In general, treatments changed the individual and collective behaviors of C. brevis pseudergates, as well as the displacement and walking speed. The essential oil of L. sidoides and its major components showed a high potential to control C. brevis pseudergates, due to the bioactivity in the two routes of exposure and the sub-lethal effects on the behavior and walking, important activities for the cohesion of C. brevis colonies.


Assuntos
Baratas/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Lippia/química , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Madeira/efeitos dos fármacos , Animais , Dose Letal Mediana , Óleos Voláteis/isolamento & purificação , Óleos de Plantas/isolamento & purificação , Testes de Toxicidade Aguda
14.
J Econ Entomol ; 110(2): 575-583, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28334067

RESUMO

Coptotermes formosanus Shiraki are economically important subterranean termites, particularly in the Southeastern United States where they are considered invasive. Where two C. formosanus populations met, aggressive encounters resulted in blockages in tunnels, but reinvading termites unblocked obstructions or constructed new tunnels. Experiments in planar arenas in which one population of C. formosanus was baited resulted in elimination of baited termites and subsequent reinvasion of territory by neighboring termites. Territories held by unbaited neighboring termites increased significantly, nearly doubling after reinvasion. Reinvading termites consumed baits left by baited colonies and were eliminated.


Assuntos
Benzamidas/farmacologia , Hidrocarbonetos Fluorados/farmacologia , Controle de Insetos/métodos , Isópteros/efeitos dos fármacos , Isópteros/fisiologia , Animais , Comportamento Animal
15.
Pest Manag Sci ; 73(5): 991-998, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27530272

RESUMO

BACKGROUND: Myracrodruon urundeuva is a hardwood tree, and its bark, heartwood and leaf contain lectins (MuBL, MuHL and MuLL respectively) with termiticidal activity against Nasutitermes corniger. In this work, the effects of these lectins on the midgut of N. corniger workers were evaluated. RESULTS: The insects were supplied with an artificial diet containing the lectins at their respective LC50 (previously determined). At 48 h after treatment, the midguts were dissected and fixed for histopathology analyses. Toluidine-blue-stained midguts from lectin-treated workers showed disorganisation, with the presence of debris in the lumen and the absence of brush border. Fluorescence microscopy revealed that the numbers of digestive and proliferating cells were lower in lectin-treated individuals than in the control, and caspase-3 staining confirmed the occurrence of cell apoptosis. Enteroendocrine cells were not seen in the treated individuals. The midguts from treated insects showed greater staining for peroxidase than the control, suggesting that the lectins caused oxidative stress. Staining with wheat germ agglutinin conjugated to FITC revealed that the lectins interfered with the integrity of the peritrophic matrix. CONCLUSION: This study showed that termiticidal lectins from M. urundeuva cause severe injuries, oxidative stress and cell death in the midgut of N. corniger workers. © 2016 Society of Chemical Industry.


Assuntos
Anacardiaceae/química , Ingestão de Alimentos , Inseticidas/farmacologia , Mucosa Intestinal/efeitos dos fármacos , Isópteros/efeitos dos fármacos , Lectinas de Plantas/farmacologia , Animais , Suplementos Nutricionais , Isópteros/fisiologia
16.
Insect Mol Biol ; 25(6): 734-744, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27515783

RESUMO

The peritrophic matrix (PM) is a noncellular structure that lines the gut of most insects. Because of its close involvement in digestive processes and its role as a barrier against pathogens and toxins, the PM is an attractive target for pest management strategies. The objectives of this study were to (1) reduce the expression of a chitin synthase gene (Reticulitermes flavipes chitin synthase B, RfCHSB), a putative peritrophin [R. flavipes Protein with Peritrophin-A domain 1, (RfPPAD1)] and a confirmed peritrophin [R. flavipes Protein with Peritrophin-A domain 2 (RfPPAD2)] in R. flavipes by means of RNA interference, and (2) to evaluate the susceptibility of R. flavipes to termiticides and a bacterial pathogen, after silencing the target genes. Force feeding termites with 55 and 100 ng of long double-stranded RNAs (dsRNAs), targeting RfCHSB and RfPPAD2, respectively, resulted in the highest levels of transcript suppression. RfCHSB expression was reduced by 70%, whereas the transcript level of RfPPAD2 was decreased by 90%. Force feeding 100 ng/termite of a long RfPPAD1 dsRNA reduced the expression of the transcript by 30%. Challenging termites with imidacloprid, chlorantraniliprole and noviflumuron, after silencing RfCHSB, significantly increased termite mortality. Force feeding termites a dsRNA cocktail, targeting RfCHSB, RfPPAD1 and RfPPAD2, caused the highest significant increase in termite mortality after challenging the insects with imidacloprid. These results demonstrate the viability of the R. flavipes PM as a target in termite pest management.


Assuntos
Proteínas de Insetos/genética , Inseticidas/farmacologia , Isópteros/efeitos dos fármacos , Isópteros/microbiologia , Interferência de RNA , Serratia marcescens/fisiologia , Animais , Benzamidas/farmacologia , Trato Gastrointestinal/efeitos dos fármacos , Hidrocarbonetos Fluorados/farmacologia , Imidazóis/farmacologia , Proteínas de Insetos/metabolismo , Isópteros/genética , Isópteros/metabolismo , Neonicotinoides , Nitrocompostos/farmacologia , ortoaminobenzoatos/farmacologia
17.
Insect Sci ; 23(4): 543-7, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27234337

RESUMO

The hindgut of lower termites harbors various symbiotic protists, which perform varied functions in lignocellulose decomposition. As termites are social insects, the species and numbers of these flagellated protists in the termite gut vary among the different castes. Juvenile hormones (JHs) can regulate caste differentiation in termites. In this study, we used the juvenile hormone analog fenoxycarb to induce termite workers (Reticulitermes flaviceps) to differentiate into pre-soldiers. A metatranscriptomic investigation of the protistan community was then performed by 454 pyrosequencing. From a thorough analysis based on 597 312 generated reads, we found that the starch and sucrose metabolism pathway was the most abundant pathway across the metatranscriptome. The current study demonstrates that the metatranscriptome of the protistan community in termites contains an abundance of lignocellulase, which plays a vital role in termite nutrition.


Assuntos
Isópteros/microbiologia , Isópteros/parasitologia , Microbiota/genética , Transcriptoma , Animais , Celulase/genética , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/parasitologia , Isópteros/efeitos dos fármacos , Fenilcarbamatos/farmacologia , Análise de Sequência de RNA , Simbiose
18.
PLoS One ; 11(3): e0151675, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26985663

RESUMO

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a costly invasive urban pest in warm and humid regions around the world. Feeding workers of the Formosan subterranean termite genetically engineered yeast strains that express synthetic protozoacidal lytic peptides has been shown to kill the cellulose digesting termite gut protozoa, which results in death of the termite colony. In this study, we tested if Melittin, a natural lytic peptide from bee venom, could be delivered into the termite gut via genetically engineered yeast and if the expressed Melittin killed termites via lysis of symbiotic protozoa in the gut of termite workers and/or destruction of the gut tissue itself. Melittin expressing yeast did kill protozoa in the termite gut within 56 days of exposure. The expressed Melittin weakened the gut but did not add a synergistic effect to the protozoacidal action by gut necrosis. While Melittin could be applied for termite control via killing the cellulose-digesting protozoa in the termite gut, it is unlikely to be useful as a standalone product to control insects that do not rely on symbiotic protozoa for survival.


Assuntos
Venenos de Abelha/genética , Isópteros/efeitos dos fármacos , Isópteros/parasitologia , Meliteno/genética , Controle Biológico de Vetores/métodos , Animais , Antiprotozoários/administração & dosagem , Venenos de Abelha/administração & dosagem , Bioensaio , Engenharia Genética , Meliteno/administração & dosagem , Saccharomyces cerevisiae/genética
19.
J Econ Entomol ; 108(3): 962-8, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26470217

RESUMO

Termites are responsible for an estimated US$1 billion annually in property damage, repairs, pest control, and prevention. There is an urgent need of finding a better alternative way to control and prevent termites. Port-Orford-Cedar (POC) has been known to have significant levels of natural durability and termiticidal activities due to its extractive contents. In this study, 25 endophytes including 22 fungal and 3 bacterial strains were isolated from the POC. Four strains, namely, HDZK-BYF21, HDZK-BYF1, HDZK-BYF2, and HDZK-BYB11, were chosen to test their termiticidal activities. The fermentation broth of strain HDZK-BYF21 displayed the potent antimicrobial and termiticidal activities. Morphological examination and 18 S rDNA sequence analysis demonstrated that strain HDZK-BYF21 belonged to the genus Aspergillus. This finding indicates the existence of an interesting chemical symbiosis between an endophytic fungus and its host. This is also the first report on endophytes isolated from the POC that may have potential termiticidal activities. Endophytes with termiticidal activities can be grown in bioreactor to provide an inexhaustible supply of bioactive compounds and thus can be exploited commercially.


Assuntos
Anti-Infecciosos/farmacologia , Aspergillus/química , Aspergillus/fisiologia , Cupressaceae/microbiologia , Endófitos/química , Inseticidas/farmacologia , Isópteros/efeitos dos fármacos , Animais , Aspergillus/classificação , Aspergillus/genética , DNA Fúngico/genética , DNA Fúngico/metabolismo , Endófitos/classificação , Endófitos/genética , Endófitos/fisiologia , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , RNA Ribossômico 18S/genética , RNA Ribossômico 18S/metabolismo , Análise de Sequência de DNA
20.
An Acad Bras Cienc ; 87(2): 743-51, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26131633

RESUMO

Wood extractives from heartwood of Callophylum inophyllum (bintangor) were obtained by shaker method and analyzed for their constituents by gas chromatography-mass spectrometry (GC-MS). Ten compounds were identified by ethanol (EtOH) solvents, fourteen by methanol (MeOH) and only nine by petroleum ether (PETETHR). Major compounds were contributed by monoterpenes (75.11%, 53.75%) when extracted with EtOH and PETETHR solvents. The anti-termitic assay of the wood extracts was also investigated against Coptotermes curvignathus. The level of concentration for anti-termite activity may be an indication of the dose application of the wood extracts for new development of termiticide.


Assuntos
Calophyllum/química , Isópteros/efeitos dos fármacos , Extratos Vegetais/farmacologia , Animais , Cromatografia Gasosa-Espectrometria de Massas , Madeira/química
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