Phytochemistry, toxicology, and food potential of velvetbean (Mucuna Adans. spp., Fabaceae)

Abstract in English and FrenchIn IDL-1387

Essential oils in insect control: Low-risk products in a high-stakes world

In recent years, the use of essential oils (EOs) derived from aromatic plants as low-risk insecticides has increased considerably owing to their popularity with organic growers and environmentally conscious consumers. EOs are easily produced by steam distillation of plant material and contain many volatile, low-molecular-weight terpenes and phenolics. The major plant families from which EOs are extracted include Myrtaceae, Lauraceae, Lamiaceae, and Asteraceae. EOs have repellent, insecticidal, and growth-reducing effects on a variety of insects. They have been used effectively to control preharvest and postharvest phytophagous insects and as insect repellents for biting flies and for home and garden insects. The compounds exert their activities on insects through neurotoxic effects involving several mechanisms, notably through GABA, octopamine synapses, and the inhibition of acetylcholinesterase. With a few exceptions, their mammalian toxicity is low and environmental persistence is short. Registration has been the main bottleneck in putting new products on the market, but more EOs have been approved for use in the United States than elsewhere owing to reduced-risk processes for these materials. © 2012 by Annual Reviews. All rights reserved

Resistance in maize to Sitophilus zeamais

Rev. versio

Real-time fluorescence-based detection of furanocoumarin photoadducts of DNA

Real-time fluorescence detection systems were adapted to identify DNA adducts formed by photogenotoxic phytochemicals. Two assays were developed: the first was based on quantitative polymerase chain reaction (qPCR) while the second used thermal denaturation and renaturation (D-R). Both assays employed yeast DNA, the fluorescent dye SYBR Green and a real-time PCR thermocycler. The furanocoumarins 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP), psoralen, angelicin and imperatorin, and the furanochrome khellin, were tested for adduct forming ability with up to 2 h of UVA light exposure (λ = 320-400 nm). The known bifunctional compounds, 8-MOP, 5-MOP and psoralen, were inferred to form biadducts here based on both D-R and qPCR assays, as expected from previous research. The known monofunctional compound angelicin was used as a negative control and did not form biadducts based on either assay. Two compounds of unknown functional specificity, imperatorin and khellin, were determined to be positive and negative for biadduct activity, respectively. Detection of biadducts with 8-MOP, 5-MOP, psoralen and imperatorin, but not angelicin or khellin, was further verified by temperature gradient gel electrophoresis. The fluorescence methods improve and expand upon existing assays to monitor DNA adducts. Copyrigh

Soluble phenolic content as an indicator of sorghum grain resistance to Sitophilus oryzae (Coleoptera: Curculionidae)

Eight land races of sorghum collected in Ethiopia were found to show significant variation by genotype in soluble phenolic content. Phenolic content, as catechin equivalents, was measured by the Prussian blue procedure. Variation in storage insect resistance was demonstrated using standardized tests with the rice weevil, Sitophilus oryzae. Significant inverse linear relationships were also found between resistance parameters such as weight loss of grain, the Dobie index of susceptibility, number of eggs laid and progeny emerged and the phenolic content of the grain (r2=0.85, 0.55, 0.46 and 0.52 respectively). The results suggest that the soluble phenolic content, which previous studies have shown to consist primarily of proanthocyanidins, can be used as an indicator of resistance