Universidade Federal de Viçosa

About: Universidade Federal de Viçosa is a(n) education organization based out in Viçosa, Brazil. It is known for research contribution in the topic(s): Population & Dry matter. The organization has 16012 authors who have published 26711 publication(s) receiving 353416 citation(s).

Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi

Abstract: Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.

GENES: a software package for analysis in experimental statistics and quantitative genetics

Abstract: GENES is a software package used for data analysis and processing with different biometric models and is essential in genetic studies applied to plant and animal breeding It allows parameter estimation to analyze biological phenomena and is fundamental for the decision-making process and predictions of success and viability of selection strategies The program can be downloaded from the Internet (http://wwwufvbr/dbg/genes/geneshtm or http://wwwufvbr/dbg/biodatahtm) and is available in Portuguese, English and Spanish Specific literature (http://wwwlivrariaufvbr/) and a set of sample files are also provided, making GENES easy to use The software is integrated into the programs MS Word, MS Excel and Paint, ensuring simplicity and effectiveness in data import and export of results, figures and data It is also compatible with the free software R and Matlab, through the supply of useful scripts available for complementary analyses in different areas, including genome wide selection, prediction of breeding values and use of neural networks in genetic improvement

Photosynthesis and activity of superoxide dismutase, peroxidase and glutathione reductase in cotton under salt stress

Abstract: The effects of NaCl stress on the activity of antioxidant enzyme such as superoxide dismutase (SOD: EC 1.15.1.1), peroxidase (POD: EC 1.11.1.7), glutathione reductase (GR: EC 1.6.4.2), rate of lipid peroxidation, gas-exchange, chlorophyll content and chlorophyll fluorescence were investigated in two cotton cultivars, Guazuncho and Pora (hybrids between Gossypium hirsutum × G. arboretum × G. raimondii ) grown in nutrient solution. Plants were treated with three salt concentrations (50, 100 and 200 mol m −3 NaCl) for 21 days. The SOD activity in Pora increases with the increase in the intensity of NaCl stress, but salt treatment had no significant effect on this enzyme activity in Guazuncho. The POD and GR activities showed similar trends under salt stress, in both cotton cultivars. In Pora, there was an average increase in GR activity of about 53%, but there was no further increase at higher NaCl concentrations. In Guazuncho, no change in GR activity was observed. Net photosynthesis and stomatal conductance decreased in response to salt stress, but Pora showed a smaller reduction in photosynthesis than Guazuncho. The results indicated that stomatal aperture limited leaf photosynthetic capacity in the NaCl-treated plants of both cultivars. However, significant reduction in the leaf chlorophyll contents due to NaCl stress was observed only on Guazuncho. In both cotton cultivars, the photochemical efficiency of PSII was not affected by salt stress. These results suggest that salt-tolerant cotton varieties may have a better protection against reactive oxygen species (ROS) by increasing the activity of antioxidant enzymes under salt stress.

Zinc Oxide Nanoparticles: Synthesis, Antimicrobial Activity and Food Packaging Applications

Abstract: Zinc oxide (ZnO) is an inorganic compound widely used in everyday applications. ZnO is currently listed as a generally recognized as safe (GRAS) material by the Food and Drug Administration and is used as food additive. The advent of nanotechnology has led the development of materials with new properties for use as antimicrobial agents. Thus, ZnO in nanoscale has shown antimicrobial properties and potential applications in food preservation. ZnO nanoparticles have been incorporated in polymeric matrices in order to provide antimicrobial activity to the packaging material and improve packaging properties. This review presents the main synthesis methods of ZnO nanoparticles, principal characteristics and mechanisms of antimicrobial action as well as the effect of their incorporation in polymeric matrices. Safety issues such as exposure routes and migration studies are also discussed.

Geminivirus strain demarcation and nomenclature

Abstract: Geminivirus taxonomy and nomenclature is growing in complexity with the number of genomic sequences deposited in sequence databases Taxonomic and nomenclatural updates are published at regular intervals (Fauquet et al in Arch Virol 145:1743–1761, 2000, Arch Virol 148:405–421, 2003) A system to standardize virus names, and corresponding guidelines, has been proposed (Fauquet et al in Arch Virol 145:1743–1761, 2000) This system is now followed by a large number of geminivirologists in the world, making geminivirus nomenclature more transparent and useful In 2003, due to difficulties inherent in species identification, the ICTV Geminiviridae Study Group proposed new species demarcation criteria, the most important of which being an 89% nucleotide (nt) identity threshold between full-length DNA-A component nucleotide sequences for begomovirus species This threshold has been utilised since with general satisfaction More recently, an article has been published to clarify the terminology used to describe virus entities below the species level [5] The present publication is proposing demarcation criteria and guidelines to classify and name geminiviruses below the species level Using the Clustal V algorithm (DNAStar MegAlign software), the distribution of pairwise sequence comparisons, for pairs of sequences below the species taxonomic level, identified two peaks: one at 85–94% nt identity that is proposed to correspond to “strain” comparisons and one at 92–100% identity that corresponds to “variant” comparisons Guidelines for descriptors for each of these levels are proposed to standardize nomenclature under the species level In this publication we review the status of geminivirus species and strain demarcation as well as providing updated isolate descriptors for a total of 672 begomovirus isolates As a consequence, we have revised the status of some virus isolates to classify them as “strains”, whereas several others previously classified as “strains” have been upgraded to “species” In all other respects, the classification system has remained robust, and we therefore propose to continue using it An updated list of all geminivirus isolates and a phylogenetic tree with one representative isolate per species are provided