Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees

The Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available. © 2019 Elsevier B.V

Antimicrobial activity and rutin identification of honey produced by the stingless bee Melipona compressipes manaosensis and commercial honey

Background: Honey has been identified as a potential alternative to the widespread use of antibiotics, which are of significant concern considering the emergence of resistant bacteria. In this context, this study aimed to evaluate the antimicrobial activity of honey samples produced by a stingless bee species and by Apis sp. against pathogenic bacteria, as well as to identify the presence of phenolic compounds.Methods: Honey samples from the stingless bee M. compressipes manaosensis were collected twice, during the dry and rainy seasons. Three commercial honey samples from Apis sp. were also included in this study. Two different assays were performed to evaluate the antibacterial potential of the honey samples: agar-well diffusion and broth macrodilution. Liquid-liquid extraction was used to assess phenolic compounds from honey. HPLC analysis was performed in order to identify rutin and apigenin on honey samples. Chromatograms were recorded at 340 and 290 nm.Results: Two honey samples were identified as having the highest antimicrobial activity using the agar diffusion method. Honey produced by Melipona compressipes manaosensis inhibited the growth of Staphylococcus aureus, Escherichia coli (0157: H7), Proteus vulgaris, Shigella sonnei and Klebsiella sp. A sample of honey produced by Apis sp. also inhibited the growth of Salmonella paratyphi. The macrodilution technique presented greater sensitivity for the antibacterial testing, since all honey samples showed activity. Flavonoid rutin was identified in the honey sample produced by the stingless bee.Conclusions: Honey samples tested in this work showed antibacterial activity against Gram-positive and Gram-negative bacteria. The results reported herein highlight the potential of using honey to control bacterial growth. © 2013 Pimentel et al.; licensee BioMed Central Ltd

Variability and antifungal activity of volatile compounds from Aniba rosaeodora Ducke, harvested from Central Amazonia in two different seasons

Finding new applications for the essential oils (EOs) of the branches and leaves of Aniba species represents a valuable strategy for the adoption of correct management of the crown and to help make Aniba plantations economically valuable. We report here the antifungal activity of the EO from Aniba rosaeodora Ducke against plant pathogenic fungi. The present study investigated the chemical variability and antifungal effect of EO from A. rosaeodora harvested during the wet and dry seasons in the Amazon region. The volatile content obtained from the aerial parts by hydro-distillation was analyzed for its chemical composition by gas chromatography–mass spectrometry (GC–MS). Furthermore, a broth and agar dilution method was used to determine the antifungal activity against phytopathogens. Quantitative and qualitative variations in composition among the EOs were detected. Linalool was a major component in the oil of leaves and branches from both periods. Quantification using an external standard showed a higher concentration of linalool in the wet season (74.4 ± 3.9% in leaves and 81.8 ± 5.7% in branches) than in the dry season (47.5 ± 2.2 in leaves and 49.2 ± 1.6% in branches). The EOs were toxic to all phytopathogens analyzed, displaying superior inhibitory activity toward Colletotrichum guaranicola, with inhibition zone diameters ranging from 15.2 ± 1.2 to 21.3 ± 1.7 mm and IC50 values of 0.578 to 2.094 μL mL−1. Interestingly, the EOs collected during the wet season were effective in reducing the vegetative growth of phytopathogens, providing evidence for the involvement of linalool in the inhibitory effect. © 2018 Elsevier B.V

Detecção de rotavírus em um cão doméstico na cidade de Manaus-AM Rotavirus detection in a domestic dog in the City of Manaus-AM

Os rotavírus do grupo A, são frequentemente associados com gastroenterites em mamíferos e aves. O objetivo deste trabalho foi detectar a presença de rotavírus em fezes de cães sintomáticos e assintomáticos para diarréia aguda. Foram coletadas 32 amostras de fezes de cães. Todas as amostras foram submetidas à extração do RNA viral seguida da Eletroforese em Gel de Poliacrilamida (EGPA), onde se identificou apenas 1 (um) caso de infecção por rotavírus, em amostra assintomática. A análise do eletroferótipo mostrou um perfil 4:2:3:2 longo, e a homologia dos eletroferótipos de rotavírus humano e canino foi muito alta, sugerindo uma possível infecção interespécie.<br>The group A rotaviruses are frequently associated with gastroenteritis in mammals and birds. The objective of this study was to detect the presence of rotavirus in feces of symptomatic and asymptomatic dogs for acute diarrhea. 32 samples of dog feces were collected. All the samples were submitted to viral RNA extraction followed by electrophoresis in poliacrylamide gels (PAGE), where only one case of rotavirus infection in one asymptomatic sample was found. The electrophoretic analysis showed 4:2:3:2 long profile, and the homology between human and dog rotaviruses was very high. This suggests a possible interspecies infection