Luzimar Gonzaga Fernandez

Lipidomics in the study of lipid metabolism: Current perspectives in the omic sciences.

The advances in systems biology and in the development of new technological tools in analysis, as well as in the omic sciences, among which, metabolomics, and more specifically, lipidomics, have made it possible to investigate the structural and functional complexity of lipids in biological systems. Liquid chromatography and mass spectrometry are the analytical approaches most used in lipid research. Biomedical research, with the development of specific markers for lipids, together with new software development, have both enabled the early diagnosis of several illnesses, besides the evaluation of drug activity and treatment efficacy.

Physiological and biochemical responses of Ricinus communis seedlings to different temperatures: a metabolomics approach

BackgroundCompared with major crops, growth and development of Ricinus communis is still poorly understood. A better understanding of the biochemical and physiological aspects of germination and seedling growth is crucial for the breeding of high yielding varieties adapted to various growing environments. In this context, we analysed the effect of temperature on growth of young R. communis seedlings and we measured primary and secondary metabolites in roots and cotyledons. Three genotypes, recommended to small family farms as cash crop, were used in this study.ResultsSeedling biomass was strongly affected by the temperature, with the lowest total biomass observed at 20°C. The response in terms of biomass production for the genotype MPA11 was clearly different from the other two genotypes: genotype MPA11 produced heavier seedlings at all temperatures but the root biomass of this genotype decreased with increasing temperature, reaching the lowest value at 35°C. In contrast, root biomass of genotypes MPB01 and IAC80 was not affected by temperature, suggesting that the roots of these genotypes are less sensitive to changes in temperature. In addition, an increasing temperature decreased the root to shoot ratio, which suggests that biomass allocation between below- and above ground parts of the plants was strongly affected by the temperature. Carbohydrate contents were reduced in response to increasing temperature in both roots and cotyledons, whereas amino acids accumulated to higher contents. Our results show that a specific balance between amino acids, carbohydrates and organic acids in the cotyledons and roots seems to be an important trait for faster and more efficient growth of genotype MPA11.ConclusionsAn increase in temperature triggers the mobilization of carbohydrates to support the preferred growth of the aerial parts, at the expense of the roots. A shift in the carbon-nitrogen metabolism towards the accumulation of nitrogen-containing compounds seems to be the main biochemical response to support growth at higher temperatures. The biochemical changes observed in response to the increasing temperature provide leads into understanding plant adaptation to harsh environmental conditions, which will be very helpful in developing strategies for R. communis crop improvement research.

Metabolite profiling, antioxidant and antibacterial activities of Brazilian propolis: Use of correlation and multivariate analyses to identify potential bioactive compounds

The production of propolis by honeybees results from a selective collection of exudates from various plant species and present many potentialities in the pharmaceutical industry. The objective of this study was to investigate the chemical profile of Brazilian propolis, as well as their in vitro antioxidant and antibacterial activities. Gas chromatography-mass spectrometry was applied for chemical profiling of propolis extracts. Total phenolic compounds were quantified by Folin-Ciocalteu and antioxidant properties were assessed by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Antibacterial activity was assessed against Staphylococcus aureus, Bacillus subtilis, and Micrococcus luteus. Correlation and multivariate statistical analysis were used to identify potential bioactive compounds in the extracts. Twenty-nine metabolites were identified along with 34 other metabolites that were classified into the following classes: triterpenoids (12), acetyltriterpenoids (3), sesquiterpenes (6), steroids (4), and hydrocarbons (9). The antioxidant capacity (IC50) ranged from 21.50 to 78.77μg/mL, whereas the content of total phenolic compounds ranged from 31.88 to 204.30mg GAE/g of dry weight. Total phenolic compounds and methyl retinoate showed a positive correlation with the antioxidant capacity, whereas tetradecanal, γ-palmitolactone and ethyl hydrocinnamate showed a negative correlation. Different sets of metabolites are shown to correlate with the antibacterial activity of the extracts, which is largely dependent on the type of microorganism. This innovative approach allowed us to identify likely bioactive compounds in the extracts, although the mechanism(s) underlying antibacterial activity encompass a complex trait, which might involve synergistic effects.

Compostos bioativos e atividade antioxidante de extratos brutos de espécies vegetais da caatinga

Summary This study aimed to determine the levels of bioactive phytochemicals in the seeds of native plant species from brushwood areas, Caesalpinia pyramidalis Tull, Erytrina velutina and Amburana cearensis, by the spectrophotometric quantification of the total phenolics, proanthocyanidins (condensed tannins), anthocyanins, total flavonoids and total carotenoids, and also investigate the correlation between the antioxidant activity measured using an in vitro model system of linoleic acid/ β-carotene and assess the effect of solvent extractors in the matrices studied. The levels of condensed tannins, analyzed using the acid butanol method, expressed in leucocianidin equivalents, were higher for Erytrina velutina, whereas for condensed tannins analyzed by the vanillin method and expressed as catechin equivalents, the highest values were found for C. pyramidalis. It was found that the levels of flavonoids, anthocyanins, carotenoids and total phenols were higher for C. pyramidalis as compared to the other species, besides presenting higher protein and lipid contents. The ethanol extracts of C. pyramidalis stood out for their greater antioxidant activity and correlation with the total phenolic content, thus presenting a potential source of phenolic compounds for application in the food and pharmaceutical industries.

Divergência genética entre cinco cultivares de mamoneira

The objective of this work was to evaluate the genetic divergence between castor bean (Ricinus communis L.) cultivars, from adaptative traits, yield components and cultivars productivity. The experiment in a randomized blocks design with five treatments and five replications was carried out in a Xanthic Hapludox in Cruz das Almas, BA, Brazil. Data were submitted to the variance analysis and the average values had been commanded according to Scott-Knott test (a = 0.05). Based on multivariate analysis, the genetic divergence was determined using cluster analysis and principal components analysis. Tree groups were formed, and the one which comprised the cultivate more divergent, Mirante 10, is not recommended for hybridization due to its low performance. Promising combinations are those ones found between Sipeal 28 x BRS 188 Paraguacu, Sipeal 28 x BRS 149 Nordestina, EBDA MPA 17 x BRS 188 Paraguacu and EBDA MPA 17 x BRS 149 Nordestina, due to the dissimilarity and the best average performance of these genotypes.

Comportamento fisiológico de sementes de Myracrodruon urundeuva Fr. All. (Anacardiaceae) submetidas a fatores abióticos

The aim of this work was to evaluate germinating seeds of Myracrodruon urundeuva under different temperatures and hydrous potentials, the combination of both and the seeds viability after osmotic conditioning. The assay was conducted in a totally casual analysis with four repetition contained 50 seeds by treatment. The temperatures of 20, 25, 30, 33, 35 and 40 oC were tested with seeds soaked in distilled water. In another assay, the osmotic potentials of 0,0 (evidence) were tested; -0,2; -0,4; -0,6; -0,7; -0,8; -0,9; -1,0 e -1,2 MPa using PEG 6000 solutions. Based in these tests, it was established the best temperatures and the osmotic potentials of maximum germination, fifty percent of germination and no germination. After end of hydrous screening, no germinating seeds in no germinating potentials was tested for its capacity of germinating in water. Also, different temperatures were combined with different osmotic potentials. The seed germination Myracrodruon urundeuva starts in two days. At the temperature of 25 oC, it was obtained for maximum seed germination of the species at 33 oC for 50 % of the seeds germinated and at 40 oC, the germination was zero. Regarding to water restriction induced -0.2 MPa, it was an optimum germination potential, the potential of -0.7 MPa 50 % germination and from -0.9 MPa and germination was nil. The osmotic potentials of -0.9, -1.0 and -1.2 MPa, can be used for priming this species. The seeds of Myracrodruon urundeuva not tolerate the stresses of high temperatures and decreased water potential, concurrently, as they reduce the germination and seed vigor

Avaliação da atividade antibacteriana dos extratos de Avicennia schaueriana Stapf & Leechm. ex Moldenke, Verbenaceae

Natural products have been a valuable bioactives constituent source for maintenance of the health human being. Such fact has strengthened the increasing inquiry of the therapeutical potential of medicinal plants. This work had as objective evaluate the antibacterial potential from leaf, root and bark hydro-alcoholics extracts of Avicennia schaueriana Stapf & Leechm. ex Moldenke, Verbenaceae. The plant parts had been collected in the fishing town of Siribinha, Bahia and the plant extracts had been prepared by the method of maceration. All the tests of sensitivity of plant extracts had been evaluated by means of notparametric tests. The results of the test of diffusion in disk showed that the extract of the root of the A. schaueriana had been higher to extracts of the leaf and bark, with inhibition rings from growth varying of 7 to 18 mm; in accordance with the tested concentrations. Already the minimum inhibitory concentration of hydro-alcoholic extracts of A. schaueriana had presented an average of values between 0,62 to 10,00 mg/mL for the analyzed bacteria. The statistical results had confirmed the difference of sensitivity of the studied microorganisms front to extracts of the A. schaueriana.

Metabolite profiling of Ricinus communis germination at different temperatures provides new insights into thermo-mediated requirements for successful seedling establishment

Ricinus communis seeds germinate to a high percentage and faster at 35 °C than at lower temperatures, but with compromised seedling establishment. However, seedlings are able to cope with high temperatures at later stages of seedling establishment if germination occurred at lower temperatures. Our objective was to assess the biochemical and molecular requirements of R. communis germination for successful seedling establishment at varying temperatures. For that, we performed metabolite profiling (GC-TOF-MS) and measured transcript levels of key genes involved in several energy-generating pathways, such as storage oil mobilization, β-oxidation and gluconeogenesis of seeds germinated at three different temperatures. We identified a thermo-sensitive window during seed germination in which high temperatures compromise seedling development, most likely by down-regulating some energy-generating pathways. Overexpression of malate synthase (MLS) and glycerol kinase (GK) genes resulted in higher starch levels in Nicotiana benthamiana leaves, which highlights the importance of these genes in energy-generating pathways for seedling establishment. Additionally, we showed that GABA, which is a stress-responsive metabolite, accumulated in response to the water content of the seeds during the initial phase of imbibition. Herewith, we provide new insights into the molecular requirements for vigorous seedling growth of R. communis under different environmental conditions.

Caracterização morfoanatomica e fisiológica de sementes e plântulas de Jatropha curcas L. (Euphorbiaceae)

Jatropha curcas L., conhecida popularmente como pinhao-manso, e uma especie encontrada em quase todas as regioes intertropicais do planeta. Possui sementes oleaginosas de importância medicinal e economica, sendo apontada atualmente como promissora fonte de materia-prima para a producao de biocombustiveis. Os objetivos deste trabalho consistiram em identificar as diferentes fases do processo de germinacao, descrever e ilustrar a morfologia de sementes e plântulas de Jatropha curcas L. e os aspectos anatomicos das sementes, relacionando as mudancas que ocorrem nos tecidos durante as fases de embebicao. Para a analise morfologica das sementes e plântulas, observaram-se os detalhes externos e internos. Para o estudo das fases de germinacao, foi realizado um ensaio para avaliar o comportamento das sementes durante a embebicao; para a analise anatomica, foram preparadas lâminas permanentes com cortes das sementes apos 0, 4, 24 e 72 h de embebicao. As sementes de Jatropha curcas L. sao endospermaticas, elipticas e anatropas com tegumento glabro, possuindo poros e fissuras em sua superficie. Os cotiledones sao foliaceos, com formato cordiforme e nervuras trinervias. A germinacao e do tipo fanerocotiledonar, epigea. Anatomicamente, as sementes sao albuminosas, sendo o tegumento constituido de celulas parenquimaticas, vacuoladas e poligonais com feixes vasculares e celulas esclereficadas. O endosperma e composto por celulas poliedricas ricas em substâncias de reserva, principalmente lipidios. Durante as fases de germinacao, observaram-se alteracoes no acumulo de grânulos de amido presentes no endosperma, bem como mudancas na organizacao dos seus feixes vasculares.

Atividade antibacteriana in vitro de extratos de Rhizophora mangle L.

Assays to evaluate the antibacterial potential of Rhizophora mangle (red mangrove), sampled at Conde Municipality, Bahia State, Brazil, were performed against Gram-positive (Staphylococcus aureus ATCC 6538 and Micrococcus luteus ATCC 9341) and Gram-negative (Echerichia coli ATCC 10536, Salmonella Cholerea-suis 10708, Klebsiela pneumoniae ATCC 700603 and Pseudomonas aeruginosa ATCC 15442) bacteria. Antibacterial activity was evaluated by disc diffusion and minimal inhibitory concentration (MIC) and results were statistically analyzed. The results of disc diffusion assay showed a significant difference as to the sensitivity of microorganisms against the tested extracts (p<0.05). The MIC of leaf extract (313 µg mL-1) indicated the best performance to inhibit the growth of Gram-positive strains, while bark extract had a better efficacy against Gram-negative strains. Based on the presented data, R. mangle showed antibacterial properties against both Gram-positive and Gram-negative strains and can be used as an alternative therapy for popular use or for the pharmaceutical industry.