Larvicidal (against Aedes aegypti Linnaeus, 1762) and molluscicidal (against Biomphalaria glabrata Say, 1818) activities of several natural and synthetic naphthoquinones were measured, with significant results. The best larvicidal compound is 3-bromojuglone, while the better molluscicides are 2-bromo- and 3-bromo-5-acetoxy-1,4-naphthoquinones together with the 3-bromo-5-methoxy derivative. The present results reinforce the potential use of substituted hydroxyquinones, their salts and halogenated quinones as very promising compounds against 4th instar larves of Aedes aegypti, the vector of dengue and against adult snail of Biomphalaria glabrata.

Aphids use chemical cues to locate hosts and find mates. The vetch aphid Megoura viciae feeds exclusively on the Fabaceae, whereas the currant-lettuce aphid Nasonovia ribisnigri alternates hosts between the Grossulariaceae and Asteraceae. Both species use alarm pheromones to warn of dangers. For N. ribisnigri this pheromone is a single component (E)-β-farnesene but M. viciae uses a mixture of (E)-β-farnesene, (−)-α-pinene, β-pinene, and limonene. Odorant-binding proteins (OBP) are believed to capture and transport such semiochemicals to their receptors. Here, we report the first aphid OBP crystal structures and examine their molecular interactions with the alarm pheromone components. Our study reveals some unique structural features: 1) the lack of an internal ligand binding site; 2) a striking groove in the surface of the proteins as a putative binding site; 3) the N-terminus rather than the C-terminus occupies the site closing off the conventional OBP pocket. The results from fluorescent binding assays, molecular docking and dynamics demonstrate that OBP3 from M. viciae can bind to all four alarm pheromone components and the differential ligand binding between these very similar OBP3s from the two aphid species is determined mainly by the direct π-π interactions between ligands and the aromatic residues of OBP3s in the binding pocket.

Coupling several natural and synthetic lures with aggregation pheromones from the palm weevils Rhynchophorus palmarum and R. ferrugineus reveals a synergy that results in an increase in pest captures. The combined attraction of pure pheromones, ethyl acetate, and decaying sweet and starchy plant tissue increases the net total of mass-trapped weevils. The 2018 entrance of the red palm weevil (RPW) into South America has threatened palm-product income in Brazil and other neighboring countries. The presence of the new A1 quarantine pest necessitates the review of all available options for a sustainable mass-trapping, monitoring, and control strategy to ultimately target both weevils with the same device. The effective lure-blend set for the mass-trapping system will attract weevils in baiting and contaminating stations for entomopathogenic fungi that the same weevils will spread.

This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40 μg·mL−1 (11.1460 μg·mL−1 and 25.8689 μg·mL−1, resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40 μg·mL−1 (29.018 μg·mL−1 and 17.230 μg·mL−1, resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277 μg·mL−1 and 706.990 μg·mL−1) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar.

This study evaluated the antimicrobial activity of the ethanol extract of Annona crassiflora Mart., against the fungus, Candida albicans present in the oral microbiota. The tests showed that the fractions of ethanol extract of the root bark and wood root of A. crassiflora showed a positive result. Of the strains studied, three showed sensitivity to 12 fractions and sub-fractions of A. crassiflora (66%). In the strains studied, strain 05 was the one that proved the most sensitive statistically (p <0.05). Their structures were determined using spectral techniques (NMR 1H and 13C) and based on literature data.

A cana-de-açúcar é uma cultura de grande importância para a agricultura e economia brasileira. Essa cultura pode sofrer ataques de diversas pragas que causam danos econômicos severos no tocante a produtividade. No presente trabalho investigamos os Compostos Orgânicos Voláteis (COVs) liberados por plantas de cana-de-açúcar submetidas a dois tratamentos de herbivoria simulada. Na Herbivoria Simulada Única (HSU), a planta é danificada mecanicamente uma única vez, entretanto na Herbivoria Simulada Dupla (HSD), a planta é danificada mecanicamente por duas vezes. Os experimentos foram avaliados em três tempos diferentes (24, 48 e 72 horas). As plantas apresentaram diferentes perfis de COVs quando submetidas aos tratamentos. A (Z)-jasmona e a sulcatona foram emitidos em maior quantidade pelas plantas do tratamento HSD após 24 e 48 horas de indução sendo que 48 horas após a indução que esse composto apresentou diferença significativa em relação quantidade emitida pelas plantas do tratamento HSU. Esses achados fornecem uma indicação de que as plantas são capazes de implementar defesas contra o ataque de herbívoro, pela emissão de compostos que repelem insetos e atraem parasitóides e ou predadores.

The aim of this study was to evaluate the type of microbiota present in root canals with pulp necrosis, with and without periapical lesion. Nineteen patients were selected for the study and 30 root canals were analysed in unirradicular and/or multi-radicular permanent teeth, asymptomatic, with pulp necrosis, with or without periapical lesion, and no communication between root canal and oral cavity. Absorbent paper cones were introduced in the canal for 20 s. Then, the contaminated paper cones were inoculated in a Brain Heart Infusion Agar-BHI culture medium and incubated in an oven for 48 h at 37°C. The data were analysed by non-parametric statistical method of the Cochran-test. The results revealed that there was no statistically significant difference between the amount of Gram-positive and negative bacteria in endodontic infections, indicating that the microbiota of these endodontic infections is mixed.