State University of Santa Cruz

About: State University of Santa Cruz is a education organization based out in Ilhéus, Brazil. It is known for research contribution in the topics: Population & Species richness. The organization has 3266 authors who have published 4642 publications receiving 51876 citations. The organization is also known as: Universidade Estadual de Santa Cruz.

The pathogenesis-related protein PR-4b from Theobroma cacao presents RNase activity, Ca 2+ and Mg 2+ dependent-DNase activity and antifungal action on Moniliophthora perniciosa

Abstract: Background: The production and accumulation of pathogenesis-related proteins (PR proteins) in plants in response to biotic or abiotic stresses is well known and is considered as a crucial mechanism for plant defense. A pathogenesis-related protein 4 cDNA was identified from a cacao-Moniliophthora perniciosa interaction cDNA library and named TcPR-4b. Results: TcPR-4b presents a Barwin domain with six conserved cysteine residues, but lacks the chitin-binding site. Molecular modeling of TcPR-4b confirmed the importance of the cysteine residues to maintain the protein structure, and of several conserved amino acids for the catalytic activity. In the cacao genome, TcPR-4b belonged to a small multigene family organized mainly on chromosome 5. TcPR-4b RT-qPCR analysis in resistant and susceptible cacao plants infected by M. perniciosa showed an increase of expression at 48 hours after infection (hai) in both cacao genotypes. After the initial stage (24-72 hai), the TcPR-4b expression was observed at all times in the resistant genotypes, while in the susceptible one the expression was concentrated at the final stages of infection (45-90 days after infection). The recombinant TcPR-4b protein showed RNase, and bivalent ions dependent-DNase activity, but no chitinase activity. Moreover, TcPR-4b presented antifungal action against M. perniciosa, and the reduction of M. perniciosa survival was related to ROS production in fungal hyphae. Conclusion: To our knowledge, this is the first report of a PR-4 showing simultaneously RNase, DNase and antifungal properties, but no chitinase activity. Moreover, we showed that the antifungal activity of TcPR-4b is directly related to RNase function. In cacao, TcPR-4b nuclease activities may be related to the establishment and maintenance of resistance, and to the PCD mechanism, in resistant and susceptible cacao genotypes, respectively.

Horizontal Multilayer Soil Parameter Estimation Through Differential Evolution

Abstract: This paper presents a methodology to represent an unknown soil through a stratified horizontal multilayer soil model. It uses the experimental electrical apparent resistivity curve, obtained by measurements on the ground, using a 4-wire earth ground resistance tester kit, along with some calculations. This curve is then compared with the theoretical electrical apparent resistivity curve, obtained through calculations over a horizontally stratified soil, whose parameters are known. The horizontal multilayer soil model parameters, such as number of layers, in addition to the resistivity and thickness of each layer, are optimized by the Differential Evolution algorithm. In order for both apparent resistivity curves to get close, the model can be a representation of the unknown soil. We also present methodologies to verify the theoretical apparent resistivity calculations, by extending the characteristic curve approximation, and to improve error peaks between the apparent resistivity curves, by giving opportunities for other more uniform solutions to excel. A case study uses experimental data from other methods for further comparisons.

Early development of Moniliophthora perniciosa basidiomata and developmentally regulated genes

Abstract: The hemibiotrophic fungus Moniliophthora perniciosa is the causal agent of Witches' broom, a disease of Theobroma cacao. The pathogen life cycle ends with the production of basidiocarps in dead tissues of the infected host. This structure generates millions of basidiospores that reinfect young tissues of the same or other plants. A deeper understanding of the mechanisms underlying the sexual phase of this fungus may help develop chemical, biological or genetic strategies to control the disease. Mycelium was morphologically analyzed prior to emergence of basidiomata by stereomicroscopy, light microscopy and scanning electron microscopy. The morphological changes in the mycelium before fructification show a pattern similar to other members of the order Agaricales. Changes and appearance of hyphae forming a surface layer by fusion were correlated with primordia emergence. The stages of hyphal nodules, aggregation, initial primordium and differentiated primordium were detected. The morphological analysis also allowed conclusions on morphogenetic aspects. To analyze the genes involved in basidiomata development, the expression of some selected EST genes from a non-normalized cDNA library, representative of the fruiting stage of M. perniciosa, was evaluated. A macroarray analysis was performed with 192 selected clones and hybridized with two distinct RNA pools extracted from mycelium in different phases of basidiomata formation. This analysis showed two groups of up and down-regulated genes in primordial phases of mycelia. Hydrophobin coding, glucose transporter, Rho-GEF, Rheb, extensin precursor and cytochrome p450 monooxygenase genes were grouped among the up-regulated. In the down-regulated group relevant genes clustered coding calmodulin, lanosterol 14 alpha demethylase and PIM1. In addition, 12 genes with more detailed expression profiles were analyzed by RT-qPCR. One aegerolysin gene had a peak of expression in mycelium with primordia and a second in basidiomata, confirming their distinctiveness. The number of transcripts of the gene for plerototolysin B increased in reddish-pink mycelium and indicated an activation of the initial basidiomata production even at this culturing stage. Expression of the glucose transporter gene increased in mycelium after the stress, coinciding with a decrease of adenylate cyclase gene transcription. This indicated that nutrient uptake can be an important signal to trigger fruiting in this fungus. The identification of genes with increased expression in this phase of the life cycle of M. perniciosa opens up new possibilities of controlling fungus spread as well as of genetic studies of biological processes that lead to basidiomycete fruiting. This is the first comparative morphologic study of the early development both in vivo and in vitro of M. perniciosa basidiomata and the first description of genes expressed at this stage of the fungal life cycle.

Removal of lead ions from water using a resin of mimosa tannin and carbon nanotubes

Abstract: A large amount of input of lead to the environment has resulted from several economical activities and has a significant impact on water resources. The reduction of lead contamination in water is an important issue for the environmental and human health. This study aimed to synthesize a tannin–formaldehyde resin with the inclusion of carbon nanotubes and coconut fibers, for removal of lead in water. The concentrations of Pb(II) were measured by Energy-Dispersive X-Ray Fluorescence (EDXRF) analysis. The physical and chemical characteristics and the kinetic and isotherms adsorption parameters are reported. The synthesized resin can achieve a capacity of Pb(II) adsorption higher than 13.8 mg g −1 , showing a good alternative for its future use in the treatment of water containing toxic metals in trace concentrations.