Photophysics of Structurally Modified Flavin Derivatives in the Blue-Light Photoreceptor YtvA: A Combined Experimental and Theoretical Study

The light-induced processes of two flavin mononucleotide derivatives (1- and 5-deaza flavin mononucleotide, 1DFMN and 5DFMN), incorporated into the LOV domain of YtvA protein from Bacillus subtilis, were studied by a combination of experimental and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations were carried out in which the QM part was treated by density functional theory (DFT) using the B3LYP functional for geometry optimizations and the DFT/MRCI method for spectroscopic properties, whereas the MM part was described by the CHARMM force field. 1DFMN is incorporated into the protein binding site, yielding a red-shifted absorption band (lmax=530 nm compared to YtvA wild-type lmax=445 nm), but does not undergo any LOV-typical photoreactions such as triplet and photoadduct formation. QM/MM computations confirmed the absence of a channel for triplet formation and located a radiation-free channel (through an S1/S0 conical intersection) along a hydrogen transfer path that might allow for fast deactivation. By contrast, 5DFMN-YtvA-LOV shows a blue-shifted absorption (lmax=410 nm) and undergoes similar photochemical processes to FMN in the wild-type protein, both with regard to the photophysics and the formation of a photoadduct with a flavin-cysteinyl covalent bond. The QM/MM calculations predict a mechanism that involves hydrogen transfer in the T1 state, followed by intersystem crossing and adduct formation in the S0 state for the forward reaction. Experimentally, in contrast to wild-type YtvA, dark-state recovery in 5DFMN-YtvALOV is not thermally driven but can only be accomplished after absorption of a second photon by the photoadduct, again via the triplet state. The QM/MM calculations suggest a photochemical mechanism for dark-state recovery that is accessible only for the adduct with a C4a–S bond but not for alternative adducts with a C5–S bond

Fatores de risco, na fase de crescimento-terminação, associados a ocorrência de linfadenite em suínos.

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Uso de los tra amientos termico e no termico (alta presion hidrostatica) para la inactivación de enzimas bacterianas metaloproteases presentes en la degradación de leche.

El estudio de la aplicación de la tecnología de alta presión en el tratamiento de la leche para la inactivación de las enzimas proteolíticas puede proporcionar un producto con alta calidad y salubridad diferencial, capaz de investir en un aumento del consumo y de valor agregado, con el fin de beneficiarse de la cadena de producción, con impactos económicos y sociales

Response surface applied to mixtures of castor bean hull and presscake for organic fertilization of castor bean plants

Castor bean presscake and hull are the two sub-products resulting from the extraction of castor bean oil. Their use as organic fertilizers has aroused interest of producers who wish to aggregate value to these products and use them rationally. The growth of castor bean plants of the BRS Energia cultivar in substrates composed of mixtures of two organic materials (castor bean presscake and hull) associated to soil was evaluated in this paper. The experiment was carried out at the Embrapa Algodão greenhouse, in the city of Campina Grande, in Paraíba, Brazil, from February 2010 to June 2010. Five treatments with four replications were evaluated. The treatments were composed of soil, varying from 80 to 100%, and castor bean hull and presscake varying from 0 to 10%. In order to identify the best mixture to promote growth of the plants, the extreme-vertices experimental design was used in a simplex sub-region, due to the restrictions of some components of the mixture. The classification of the best mixture was made based on the following variables: plant height, leaf area, and total dry weight of the plant. These measurements were evaluated by mixture modeling, performed in the MATLAB® computer system. For all of the analyzed variables, the best mixture was composed of 10% of castor bean presscake, 10% of castor bean hull, and 80% of soil

Desenvolvimento de árvores nativas em sistemas silvipastoril e agrossilvipastoril na região Sudeste

Este artigo descreve o desenvolvimento de espécies florestais nativas associadas à pastagem (sistema silvipastoril) ou a cultivos agrícolas (sistema agrossilvipastoril) na região Sudeste, em zona de transição dos biomas Mata Atlântica e Cerrado. As árvores - mutambo (Guazuma ulmifolia); capixingui (Croton floribundus); angico-branco (Anadenanthera colubrina); canafístula (Peltophorum dubium), ipê felpudo (Zeyheria tuberculosa); jequitibá-branco (Cariniana estrellensis) e pau-jacaré (Piptadenia gonoacantha) - foram plantadas em faixas com três linhas de arvores, com 15 m de distância entre faixas e espaçamento 2,5 m x 2,5 m entre arvores na faixa. Duas vezes por ano (inicio e final da estação chuvosa) foram medidos altura e diâmetros do colo e à altura do peito (1,3 m) das árvores. O desenvolvimento das árvores foi maior na área de pastagem do que na área agrícola. Mutambo e capixingui destacaram-se durante todo o período experimental, apresentando maiores crescimento em altura e diâmetros aos 23 meses. As espécies de crescimento mais lento foram ipê-felpudo e jequitibá branco

Growth of native trees in two agroforestry systems.

Agroforestry systems with eucalyptus prevail in Central and Southeast Brazil, and little information is available about systems using native trees. The aim of the present study was to evaluate the development of seven native tree species grown under two agroforestry systems. The experiment was conducted starting in 2007 in 12-hectare area in the municipality of São Carlos, São Paulo state, Brazil. The tree species planted in the two systems (a silvopastoral system and an agrisilvicultural system) were: 'capixingui' (Croton floribundus) and 'mutambo' (Guazuma ulmifolia) (tutors), 'jequitibá-branco' (Cariniana estrellensis), 'canafistula' (Peltophorum dubium) and 'ipê felpudo' (Zeyheria tuberculosa) (timber trees), and 'angico-branco' (Anadenanthera colubrina) and 'pau-jacaré' (Piptadenia gonoacantha) (N-fixing trees). Data were collected for 48 months. The results show differences among tree development, which was evaluated as growth in height and diameter, as well as sensitivity to insect and disease damage. The overall results show that the agrisilvicultural system allowed better tree development. The species with best performance in the two systems were capixingui, mutambo and canafístula. Ipê-felpudo and jequitibá-branco showed the worst results. The high variability among individuals of the same species indicates the possibility of high production advances with selective breeding of these species

Phyllosticta citricarpa and sister species of global importance to Citrus.

Several Phyllosticta species are known as pathogens of Citrus spp., and are responsible for various disease symptoms including leaf and fruit spots. One of the most important species is P. citricarpa, which causes a foliar and fruit disease called citrus black spot. The Phyllosticta species occurring on citrus can most effectively be distinguished from P. citricarpa by means of multilocus DNA sequence data. Recent studies also demonstrated P. citricarpa to be heterothallic, and reported successful mating in the laboratory. Since the domestication of citrus, different clones of P. citricarpa have escaped Asia to other continents via trade routes, with obvious disease management consequences. This pathogen profile represents a comprehensive literature review of this pathogen and allied taxa associated with citrus, focusing on identification, distribution, genomics, epidemiology and disease management. This review also considers the knowledge emerging from seven genomes of Phyllosticta spp., demonstrating unknown aspects of these species, including their mating behaviour.TaxonomyPhyllosticta citricarpa (McAlpine) Aa, 1973. Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Botryosphaeriales, Family Phyllostictaceae, Genus Phyllosticta, Species citricarpa.Host rangeConfirmed on more than 12 Citrus species, Phyllosticta citricarpa has only been found on plant species in the Rutaceae.Disease symptomsP. citricarpa causes diverse symptoms such as hard spot, virulent spot, false melanose and freckle spot on fruit, and necrotic lesions on leaves and twigs.Useful websitesDOE Joint Genome Institute MycoCosm portals for the Phyllosticta capitalensis (https://genome.jgi.doe.gov/Phycap1), P. citriasiana (https://genome.jgi.doe.gov/Phycit1), P. citribraziliensis (https://genome.jgi.doe.gov/Phcit1), P. citrichinaensis (https://genome.jgi.doe.gov/Phcitr1), P. citricarpa (https://genome.jgi.doe.gov/Phycitr1, https://genome.jgi.doe.gov/Phycpc1), P. paracitricarpa (https://genome.jgi.doe.gov/Phy27169) genomes. All available Phyllosticta genomes on MycoCosm can be viewed at https://genome.jgi.doe.gov/Phyllosticta

Nanomechanical behavior of pentagraphyne-based single-layer and nanotubes through reactive classical molecular dynamics

In a recent theoretical study, a new 2D carbon allotrope called pentagraphyne (PG-yne) was proposed. This allotrope is derived from pentagraphene by introducing acetylenic linkages between sp3 and sp2 hybridized carbon atoms. Due to its interesting electronic and structural properties, it is of interest to investigate the mechanical behavior of PG-yne in both monolayer and nanotube topologies. To achieve this, we performed fully atomistic reactive (ReaxFF) molecular dynamics simulations, and our results show that Young's modulus average of PG-yne monolayers is approximately 913 GPa, at room temperature. In comparison, it ranges from 497-789 GPa for the nanotubes studied. Furthermore, we observed that PG-yne monolayers exhibit a direct transition from elastic to complete fracture under critical strain without a plastic regime. In contrast, some PG-yne nanotubes exhibit an extended flat plastic regime before total fracture

Tratamento de Livros Infestados por Broca (família Anobídeo) (ordem Coleóptera) com a Utilização de Nitrogênio (N2) Líquido.

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