The complete genome of Rachiplusia nu nucleopolyhedrovirus (RanuNPV) and the identification of a baculoviral CPD-photolyase homolog.

We described a novel baculovirus isolated from the polyphagous insect pest Rachiplusia nu. The virus presented pyramidal-shaped occlusion bodies (OBs) with singly-embed nucleocapsids and a dose mortality response of 6.9 × 103 OBs/ml to third-instar larvae of R. nu. The virus genome is 128,587 bp long with a G + C content of 37.9% and 134 predicted ORFs. The virus is an alphabaculovirus closely related to Trichoplusia ni single nucleopolyhedrovirus, Chrysodeixis chalcites nucleopolyhedrovirus, and Chrysodeixis includens single nucleopolyhedrovirus and may constitute a new species. Surprisingly, we found co-evolution among the related viruses and their hosts at species level. Besides, auxiliary genes with homologs in other baculoviruses were found, e.g. a CPD-photolyase. The gene seemed to be result of a single event of horizontal transfer from lepidopterans to alphabaculovirus, followed by a transference from alpha to betabaculovirus. The predicted protein appears to be an active enzyme that ensures likely DNA protection from sunlight.

Antifungal activity of silver nanoparticles and simvastatin against toxigenic species of Aspergillus.

Aspergillus spp. are ubiquitous fungi that grow on stored grains. Some species produce toxins that can harm human and animal health, leading to hepato- and nephrotoxicity, immunosuppression and carcinogenicity. Major fungicides used to prevent fungal growth may be toxic to humans and their repeated use over time increases levels of resistance by microorganisms. Nanotechnology is an emerging field that allows use of antimicrobial compounds in a more efficient manner. In this study, was evaluated the antifungal activity of biogenic silver nanoparticles (AgNPs, synthesized by fungi) and simvastatin (SIM, a semi-synthetic drug), alone and in combination against three toxigenic species belonging to the genera Aspergillus section Flavi (Aspergillus flavus, Aspergillus nomius and Aspergillus. parasiticus) and two of section Circumdati (Aspergillus ochraceus and Aspergillus melleus). SIM exhibited a MIC50 of 78 µg/mL against species of Section Flavi and a MIC50 of 19.5 µg/mL against species of Section Circumdati. The MIC50 of AgNPs against Aspergillus flavus, Aspergillus nomius and Aspergillus parasiticus was 8 µg/mL, while the MIC50 was 4 µg/mL against Aspergillus melleus and Aspergillus ochraceus. Checkerboard assay showed that these compounds, used alone and in combination, have synergistic and additive effects against toxicogenic species of Aspergillus. Analysis by SEM gives an idea of the effect of SIM and AgNPs alone and in combination on spore germination and vegetative growth. Ultrastructural analysis revealed that spore germination was prevented, or aberrant hyphae were formed with multilateral branches upon treatment with SIM and AgNPs. These results reveal potential benefits of using combination of AgNPs and SIM to control fungal growth.

Effect of Landfill Leachate on Cereal Nutrition and Productivity and on Soil Properties.

Landfill leachates carry nutrients, especially N and K, which can be recycled in cropping systems. We applied doses of landfill leachate (0 [Control], 32.7, 65.4, 98.1, and 130.8 m ha) three times in 2008 and three times in 2009 on a clay Rhodic Kandiudult soil. In 2009, black oat ( L.) and corn ( L.) were cropped in succession and assessed for concentration of nutrients in leaves and for shoot biomass and grain yield, respectively. As a positive control, an additional treatment with urea (120 kg ha of N) was studied in corn. Soil was sampled at four depths (down to 60 cm) in three sampling dates to assess chemical and biochemical properties. Concentration of nutrients in leaves, oat biomass (8530-23,240 kg ha), and corn grain yield (4703-8807 kg ha) increased with increasing doses of leachate. There was a transient increase in the concentration of nitrate in soil (3-30 mg kg), increasing the risk of N losses by leaching at doses above 120 kg ha N, as revealed by an estimated N balance in the cropping system. Sodium and K in soil also increased with increasing doses of leachate but decreased as rainfall occurred. The activity of dehydrogenase decreased about 30% from the control to the highest dose of leachate and urea, suggesting an inhibitory effect of mineral N on microbial metabolism. Landfill leachate was promising as a source of N and K for crop productivity and caused minor or transient effects on soil properties.