Occurrence of Cu and Cr in the sedimentary humic substances and pore water from a typical sugar cane cultivation area in São Paulo, Brazil

Purpose: The purpose of this paper is to study the interactions of sedimentary humic substances (SHS) from a sugarcane cultivation area with Cu(II) and Cr(III) and to evaluate the occurrence of these metals in the pore water and SHS. Materials and methods: For this study, the northwestern region of the State of São Paulo, Brazil, which is considered the region with the highest production of sugar cane in the state, was selected. Samples of sediment were collected from four sampling sites in the Preto, Turvo, and Grande rivers. The SHS and pore water were extracted from the sediment using the method suggested by the International Humic Substances Society and centrifugation, respectively. The complexing capacity (CC) of the SHS for Cu(II) and Cr(III) was determined by individually titrating these metals with an ultrafiltration system using tangential flow. The total concentrations of Cr and Cu were determined for the pore water, sediments, and humic substances with graphite furnace atomic absorption spectrometry and Zeeman background correction after an acid digestion, according to the methods described in US EPA Method 3050B. Results and discussion: The SHS from a site in the Turvo River, which is typically cultivated with sugarcane, possessed the highest concentration of Cu bound to SHS (25.0%), the largest CC (0.63 mmol Cu g-1 HS) and the highest concentration of this metal in the pore water (1.38 mg Cu Kg-1 sed.). For Cr, the SHS collected from a location on the Preto River dam had the largest CC (0.90 mmol Cr g-1 HS) and the lowest Cr content in the pore water (0.29 mg Cr Kg-1 sed.), indicating that there was an inverse relationship between the CC and the concentration of metal available in the pore water. Conclusions: Sedimentary humic substances might be one of the regulatory factors controlling the availability of Cu and Cr in the sediments found in a typical region that has been planted with sugarcane. Distinct behaviors were observed between the two elements investigated; higher CC and a larger fraction of Cu(II) were found in the pore water of samples originating from sugarcane crops. The opposite behavior was observed for the Cr(III) species. © 2013 Springer-Verlag Berlin Heidelberg.

Estudo do comportamento térmico de hidrocarbonetos policíclicos aromáticos (HPAs) em fuligem de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção e purificação da enzima ciclodextrina glicosiltranferase: obtenção de fases sólidas e metálicas em escala nanométrica utilizando ciclodextrinas como nanorreatores

Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC

Fractionation of aquatic humic substances and dynamic of chromium species in an aquatic body influenced by sugarcane cultivation

This study had as main objectiveto evaluate the influence of AHS obtained from an area under sugarcane cultivation on the dynamics of chromium species (Cr(III) and Cr(VI)). Was studied complexing capacity (CC) with the AHS of chromium species and these were characterized using UV/Vis spectrophotometry, molecular fluorescence, elemental analysis and infrared. AHS with and without fractionation showed a greater aromaticity degree and a predominance of humic acids, and the E4/E6 and E2/E4 ratios suggested aromatic rings and a greater contribution from plants, which indicates lignin structures. The highest CCs were observed for the AHS fractionated, being fraction with molecular-size < 10 kDa and 10-30 kDa showed the highest ability to complex Cr(III) and Cr(VI) ions, respectively. These results are corroborating with C/H/N and UV/Vis data, where we can conclude that the AHS without fractionation had the greatest aromaticity and a predominance of humic acids in their structure.

Composition of Extracellular Polymeric Substances (EPS) produced by Flavobacterium columnare isolated from tropical fish in Brazil

Thirty nine isolates of Flavobacterium columnare from Brazilian fish farms had their carbohydrate composition of EPS evaluated by high efficiency liquid chromatography, using the phenol-sulfuric acid method of EPS. The occurrence of capsules on F. columnare cells was not directly related to biofilm formation, and the predominant monosaccharide is glucose.

Genetic and biochemical markers of hydroxyurea therapeutic response in sickle cell anemia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of the Extractant on the Complexing Capacity of Humic Substances from Peat for Macro and Micronutrients Using Continuous Flow: Agricultural Application and Environmental Impacts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Seasonal variability of a conditional stability constant and the characterization of sedimentary humic substances from typical agricultural and urban areas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Use of psychoactive substances in students at a public university

Introduction: The use of psychoactive substances by the student population has been the object of various studies in Brazil. Objective: To determine the prevalence of substance use among students. Methods: Quantitative study with a closed questionnaire based on standardized assessment instruments was developed. It consists of questions related to types of psychoactive substance use, abuse, frequency and duration of use, self-criticism regarding the use, consequences of use in relation to health, and misdemeanors committed under the influence of psychoactive substances. The sample included the participation of 268 students. A total of 183 (68.3%) questionnaires were analyzed, and only those with positive result for substance abuse at some point in life, the remainder, 85 (31%) questionnaires, had negative responses to psychoactive substances. Results: Students’ responses to the two years surveyed indicated that the first psychoactive substance used was alcohol (77.9%), followed by tobacco use (10.9%), and marijuana (7.6%). Of the students surveyed, 145 (79.2%) answered that still make use of psychoactive substances, and the current frequency of use varies from one or more times per week. When asked about the possibility of being or becoming drug addicts, 169 (92.3%) responded that they are not or will not become dependent. Conclusion: The results indicate the high rate of substance use among college students surveyed, and point to their contradiction to consider such psychoactive substances harmful to their health.

Peat humic substances enriched with nutrients for agricultural applications: competion between nutrients and non-essential metals present in tropical soils

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Use of HEPG2 cells to assay the safety of cosmetic active substances

The importance of this study is based on the need to obtain simple and efficient in vitro models to predict the in vivo toxicity of cosmetics, aiming not to use animals as experimental model. Here, we proposed the use of HepG2 cells, which are widely applied to simulate the hepatic function of the human organism in vitro. This cell line was chose since recent studies have shown that the liver is potentially the most frequently targeted organ by cosmetic ingredients, and beyond that, considering the widely application of in vitro assays to test the cutaneous permeation of cosmetic products, including the assays applying modified Franz cells, this technique becomes indispensable. Three different cosmetic active substances were used, and the toxicity to HepG2 cells was assessed by the MTT method. The treatment with hyaluronic acid showed no toxicity to HepG2 cells. Treating the cells with P. guajava L. extract were verified that increasing the amount of the extract in the media, the cellular viability decreased, and finally, the treatment of alpha-lipoic acid showed a cytoprotective effect in relation to the treatment with propylene glycol. The study demonstrated the suitability in using HepG2 cells to assess the safety of cosmetic active substances, helping in the prediction of if the substance could be hepatotoxic if could reach the bloodstream

Production of active recombinant eIF5A: reconstitution in E. coli of eukaryotic hypusine modification of eIF5A by its coexpression with modifying enzymes

Eukaryotic translation initiation factor 5A (eIF5A) is the only cellular protein that contains the polyamine-modified lysine, hypusine [Nε-(4-amino-2-hydroxybutyl)lysine]. Hypusine occurs only in eukaryotes and certain archaea, but not in eubacteria. It is formed post-translationally by two consecutive enzymatic reactions catalyzed by deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH). Hypusine modification is essential for the activity of eIF5A and for eukaryotic cell proliferation. eIF5A binds to the ribosome and stimulates translation in a hypusine-dependent manner, but its mode of action in translation is not well understood. Since quantities of highly pure hypusine-modified eIF5A is desired for structural studies as well as for determination of its binding sites on the ribosome, we have used a polycistronic vector, pST39, to express eIF5A alone, or to co-express human eIF5A-1 with DHS or with both DHS and DOHH in Escherichia coli cells, to engineer recombinant proteins, unmodified eIF5A, deoxyhypusine- or hypusine-modified eIF5A. We have accomplished production of three different forms of recombinant eIF5A in high quantity and purity. The recombinant hypusine-modified eIF5A was as active in methionyl-puromycin synthesis as the native, eIF5A (hypusine form) purified from mammalian tissue. The recombinant eIF5A proteins will be useful tools in future structure/function and the mechanism studies in translation.

Chitosan nanoparticles loaded the herbicide paraquat: The influence of the aquatic humic substances on the colloidal stability and toxicity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Off-line TMAH-GC/MS and NMR characterization of humic substances extracted from river sediments of northwestern Sao Paulo under different soil uses

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)