RESUMO

EPA 3051A and Aqua Regia (AR) are widely adopted by global environmental agencies to assess soil quality in relation to potentially harmful elements (PHE). However, previous study has shown the formation of large amounts of short-range order materials (SRO) in the residues of these extractions. Residues obtained from the 3051A and AR were recovered from filter papers. To characterize the SRO in these residues, sequential extractions were performed with 0.2 mol L-1 ammonium oxalate (AO) and 0.5 mol L-1 NaOH. On average (n = 15), the 3051A and AR residues contained 37% and 60% of SRO, respectively. The largest amounts of SRO formed in the AR residue was in sample 5 (99% of SRO). The main component of the SRO was Al2O3-AO, Fe2O3-AO and SiO2-NaOH. The formation of SRO and PHE resorption levels were random and highly dependent on the mineralogy of the soil clay fraction. Soils rich in smectites, which are more common in temperate regions, formed larger amounts of SRO. The association of Pb with the SRO was more pronounced in the 3051A residue than in the AR residue. If SRO was not extracted after 3051A, in sample 7, for example, 595 mg kg-1 of Pb (10.2%) would have not been accounted. The maximum PHE resorptions in SRO were (%): Pb - 10; Cu - 470; Ba - 280; As - 21. The underestimation of PHE contents due to resorption mechanisms may lead an environmental agency to certify the use of an area contaminated with PHE.

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RESUMO

Sicana odorifera is a Brazilian native fruit. In this work, cell wall polysaccharides from S. odorifera pulp were isolated by sequential extraction with water, citric acid, and sodium hydroxide solutions. The monosaccharide composition of crude polysaccharide fractions was determined. The aqueous fractions displayed the highest yields and they were constituted by pectins, having mainly galactans as side chains. The citric acid fraction (SCA) had galactose as the main component. The hemicellulosic fractions consisted mainly of xylose, mannose, galactose, and glucose, suggesting the presence of xyloglucans, xylans and mannans. The SCA fraction was further purified, resulting in a linear galactan (SCAI2). NMR and methylation analysis showed that SCAI2 was a ß-(1→4) d-galactan with molar mass of 17,560 g/mol, determined by light scattering. The presence of a linear galactan in free form in fruits is unusual because these polymers usually occur as side chains of type I rhamnogalacturonans.

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RESUMO

The sulphide-rich mine wastes accumulated in tailing dumps of La Concordia Mine (Puna of Argentina) have been exposed to the weathering action for more than 30 years. Since then, a series of redox reactions have triggered the generation of a highly acidic drainage -rich in dissolved metals-that drains into the La Concordia creek. The extent of metal and acid release in the site was analysed through field surveys and laboratory experiments. Static tests were conducted in order to predict the potential of the sulphidic wastes to produce acid, while Cu-, Zn-, Fe- and Pb-bearing phases present in the wastes were identified by XRD, SEM/EDS analysis and sequential extraction procedures. Finally, the release of these metals during sediment-water interaction was assessed in batch experiments carried out in a period of nearly two years. Field surveys indicate that the prolonged alteration of the mine wastes led to elevated electrical conductivity, pH values lower than 4 and metal concentrations that exceed the guide values for drinking water in the La Concordia stream regardless of the dominating hydrological conditions. The highly soluble Fe and Mg (hydrous)sulphates that form salt crusts on the tailings surfaces and the riverbed sediments play an important role in the control of metal mobility, as they rapidly dissolve in contact with water releasing Fe, but also Cu and Zn which are scavenged by such minerals. Another important proportion of the analysed metals is adsorbed onto Fe (hydr)oxides or form less soluble hydroxysulfates. Metals present in these phases are released to water more slowly, thus representing a potential long term source of heavy metal pollution. The obtained results are a contribution to the understanding of long term metal transformations and mobility in mine waste-impacted sites.

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RESUMO

Cell wall polysaccharides from ponkan peel were investigated with the aim of gain knowledge about their potential for different applications and the use of ponkan peel as raw material for pectin extraction. The plant material was defatted using MeOH:CHCl3, pretreated with DMSO and then subjected to sequential extractions with cold and hot water, ammonium oxalate, HCl, Na2CO3, 2 M and 4 M NaOH in order to obtain polysaccharides. The polysaccharide fractions were analyzed by chemical, chromatographic and spectroscopic methods Cold and hot water-soluble pectins contained higher amounts of GalA and higher degrees of methyl-esterification (DM) than ammonium oxalate and HCl fractions. Na2CO3 extraction provided non-esterified arabinose-rich pectins which formed gel in a dialysis step. NaOH solubilized hemicelluloses, composed mainly of xyloglucans, galactomannans and galactoglucomannans. The water-soluble fraction (WSP) was purified using α-amylase and amyloglucosidase and gave rise to the subfraction named α-WSP. The α-WSP was a pectin composed of HG and RG-I domains containing side chains of arabinans and short-chains of galactans, with low DM (39.4%) and Mw of 1.615 × 105 g/mol.

RESUMO

The reportedly low standard quality of heparin (HEP) for use in cardiac surgerieshas led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs) fromseaweeds have been regarded as promising substitutes for HEP. The aim of this study was tosequentially extract total SPs (TSPs) from Caulerpa cupressoides (Chlorophyceae) with papain in 100mM sodium acetate buffer (pH 5.0) containing 5 mM cysteine and 5 mM EDTA, followed byfractionation by ion-exchange chromatography (DEAE-cellulose), and then evaluate theanticoagulant potential of SP fractions by activated partial thromboplastin time (APTT) usingnormal human plasma and compare it to standard HEP (193 IU mg-1). The obtained fractions werechemically characterized by chemical composition and agarose gel electrophoresis. The yield was4.61%, and three fractions of SP (F I, F II and F III) eluted with 0.50, 0.75 and 1.00 M of NaCl,respectively, were observed on chromatography profiles; however, differences in charge densitiespatterns and degree of resolution among them were revealed by electrophoresis. SPs were capableof modifying APTT only in fractions eluted with 0.75 M of NaCl, whose activities were 23.37 and25.76 IU mg-1, respectively, and the charge density was prerequisite to activity. Therefore, C.cupressoides is a source of SPs possessing low anticoagulant potential compared to HEP.(AU)

O baixo padrão dequalidade outrora declarado da heparina (HEP) para o uso em cirurgias cardíacas tem levadopreocupação nos mercados nacional e internacional. Os polissacarídeos sulfatados (PSs) de algasmarinhas têm sido considerados como promissores substitutos para HEP. Objetivou-se a extrairsequencialmente PSs totais (PSTs) da clorofícea Caulerpa cupressoides com papaína em tampãoacetato de sódio 100 mM (pH 5,0) contendo cisteína 5 mM e EDTA 5 mM, fracionar porcromatografia de troca iônica (DEAE-celulose) e avaliar o potencial anticoagulante das frações dePS por meio do tempo de tromboplastina parcial ativada (TTPA), utilizando plasma humanonormal e comparando-se à HEP padrão (193 IU mg-1). As frações obtidas foram caracterizadasquimicamente em composição química e por eletroforese em gel de agarose. O rendimento dePSTs foi 4,61% e os perfis cromatográficos, em DEAE-celulose, indicaram a separação de trêsfrações de PS (F I; F II e F III) eluídas nas concentrações 0,50; 0,75 e 1,00 M de NaCl,respectivamente, revelando, por eletroforese, diferenças em termos de densidade de cargas e graude resolução. Os PSs foram capazes de modificar o TTPA somente nas frações eluídas com 0,75M de NaCl, cujas atividades foram 23,37 e 25,76 IU mg-1, respectivamente, quando a densidadede cargas foi pré-requisito para atividade. Portanto, C. cupressoides é uma fonte de PSs com baixospotenciais anticoagulantes comparados à HEP.(AU)

Assuntos

RESUMO

The reportedly low standard quality of heparin (HEP) for use in cardiac surgeries has led to concern in the Brazilian and international markets. Sulfated polysaccharides (SPs) from seaweeds have been regarded as promising substitutes for HEP. The aim of this study was to sequentially extract total SPs (TSPs) from Caulerpa cupressoides (Chlorophyceae) with papain in 100 mM sodium acetate buffer (pH 5.0) containing 5 mM cysteine and 5 mM EDTA, followed by fractionation by ion-exchange chromatography (DEAE-cellulose), and then evaluate the anticoagulant potential of SP fractions by activated partial thromboplastin time (APTT) using normal human plasma and compare it to standard HEP (193 IU mg-1). The obtained fractions were chemically characterized by chemical composition and agarose gel electrophoresis. The yield was 4.61%, and three fractions of SP (F I, F II and F III) eluted with 0.50, 0.75 and 1.00 M of NaCl, respectively, were observed on chromatography profiles; however, differences in charge densities patterns and degree of resolution among them were revealed by electrophoresis. SPs were capable of modifying APTT only in fractions eluted with 0.75 M of NaCl, whose activities were 23.37 and 25.76 IU mg-1, respectively, and the charge density was prerequisite to activity. Therefore, C. cupressoides is a source of SPs possessing low anticoagulant potential compared to HEP.

O baixo padrão de qualidade outrora declarado da heparina (HEP) para o uso em cirurgias cardíacas tem levado preocupação nos mercados nacional e internacional. Os polissacarídeos sulfatados (PSs) de algas marinhas têm sido considerados como promissores substitutos para HEP. Objetivou-se a extrair sequencialmente PSs totais (PSTs) da clorofícea Caulerpa cupressoides com papaína em tampão acetato de sódio 100 mM (pH 5,0) contendo cisteína 5 mM e EDTA 5 mM, fracionar por cromatografia de troca iônica (DEAE-celulose) e avaliar o potencial anticoagulante das frações de PS por meio do tempo de tromboplastina parcial ativada (TTPA), utilizando plasma humano normal e comparando-se à HEP padrão (193 IU mg-1). As frações obtidas foram caracterizadas quimicamente em composição química e por eletroforese em gel de agarose. O rendimento de PSTs foi 4,61% e os perfis cromatográficos, em DEAE-celulose, indicaram a separação de três frações de PS (F I; F II e F III) eluídas nas concentrações 0,50; 0,75 e 1,00 M de NaCl, respectivamente, revelando, por eletroforese, diferenças em termos de densidade de cargas e grau de resolução. Os PSs foram capazes de modificar o TTPA somente nas frações eluídas com 0,75 M de NaCl, cujas atividades foram 23,37 e 25,76 IU mg-1, respectivamente, quando a densidade de cargas foi pré-requisito para atividade. Portanto, C. cupressoides é uma fonte de PSs com baixos potenciais anticoagulantes comparados à HEP.

Assuntos

RESUMO

The Oxisols of the Cerrado region have a simple mineralogy, and are composed mainly of kaolinite and iron and aluminium oxides. The aim of this work was to perform a sequential extraction of iron and aluminium and to relate them to texture, mineralogy and organic carbon in Oxisols of the Cerrado region. The soil samples, 35 in total, were taken from the 020 cm layer in Oxisols under pasture located in the Brazilian Cerrado Region. The levels of iron and aluminum extracted by full attack, dithionite-citrate-bicarbonate, ammonium oxalate and sodium pyrophosphate were analyzed according to the textural classes using the Kruskal-Wallis nonparametric test. Then these data were related to the mineralogy and organic carbon through a principal component analysis. Whatever the textures, iron oxides of high degree of crystallinity were the main form of iron and are positively correlated with the iron total content. The aluminum oxides have a high affinity to organic carbon than iron oxides. The levels of iron and aluminum extracted by sodium pyrophosphate were closely related to soil pH.

Os Latossolos da região do Cerrado apresentam mineralogia da fração argila relativamente simples, sendo constituídos principalmente por caulinita e óxidos de ferro e de alumínio. O objetivo deste trabalho foi realizar extrações sequênciais de ferro e de alumínio e relacioná-los à mineralogia, textura e teores de carbono orgânico em Latossolos da região do Cerrado. Coletaram-se 35 amostras na camada de 0-20 cm de Latossolos sob pastagem da Região do Cerrado. Os teores de ferro e de alumínio extraídos pelo ataque total, ditionito-citrato-bicarbonato de sódio, oxalato ácido de amônia e pirofosfato de sódio foram analisados de acordo com a classe textural através do teste não paramétrico de Kruskal-Wallis. Em seguida estes dados foram relacionados com a mineralogia e o carbono orgânico por meio de uma análise de componentes principais. Independentemente da classe textural, os óxidos de ferro de alto grau de cristalinidade representaram a principal forma de ferro e se correlacionam positivamente com os teores totais de ferro. Os óxidos de alumínio apresentaram maior afinidade ao carbono orgânico do que os óxidos de ferro. Os teores de ferro e alumínio extraídos pelo pirofosfato foram estreitamente relacionados ao pH dos solos.

RESUMO

The Oxisols of the Cerrado region have a simple mineralogy, and are composed mainly of kaolinite and iron and aluminium oxides. The aim of this work was to perform a sequential extraction of iron and aluminium and to relate them to texture, mineralogy and organic carbon in Oxisols of the Cerrado region. The soil samples, 35 in total, were taken from the 020 cm layer in Oxisols under pasture located in the Brazilian Cerrado Region. The levels of iron and aluminum extracted by full attack, dithionite-citrate-bicarbonate, ammonium oxalate and sodium pyrophosphate were analyzed according to the textural classes using the Kruskal-Wallis nonparametric test. Then these data were related to the mineralogy and organic carbon through a principal component analysis. Whatever the textures, iron oxides of high degree of crystallinity were the main form of iron and are positively correlated with the iron total content. The aluminum oxides have a high affinity to organic carbon than iron oxides. The levels of iron and aluminum extracted by sodium pyrophosphate were closely related to soil pH.

Os Latossolos da região do Cerrado apresentam mineralogia da fração argila relativamente simples, sendo constituídos principalmente por caulinita e óxidos de ferro e de alumínio. O objetivo deste trabalho foi realizar extrações sequênciais de ferro e de alumínio e relacioná-los à mineralogia, textura e teores de carbono orgânico em Latossolos da região do Cerrado. Coletaram-se 35 amostras na camada de 0-20 cm de Latossolos sob pastagem da Região do Cerrado. Os teores de ferro e de alumínio extraídos pelo ataque total, ditionito-citrato-bicarbonato de sódio, oxalato ácido de amônia e pirofosfato de sódio foram analisados de acordo com a classe textural através do teste não paramétrico de Kruskal-Wallis. Em seguida estes dados foram relacionados com a mineralogia e o carbono orgânico por meio de uma análise de componentes principais. Independentemente da classe textural, os óxidos de ferro de alto grau de cristalinidade representaram a principal forma de ferro e se correlacionam positivamente com os teores totais de ferro. Os óxidos de alumínio apresentaram maior afinidade ao carbono orgânico do que os óxidos de ferro. Os teores de ferro e alumínio extraídos pelo pirofosfato foram estreitamente relacionados ao pH dos solos.

RESUMO

A crescente carência de heparina (HEP) motiva a busca por fontes alternativas de novos anticoagulantes naturais. Objetivou-se avaliar a atividade anticoagulante dos polissacarídeos sulfatados (PS) isolados de uma rodofícea do gênero Halymenia, nativa do litoral cearense, Brasil.Os PS totais foram obtidos por digestões consecutivas com papaína em tampão acetato de sódio 0,1 M (pH 5,0), contendo cisteína 5 mM e EDTA 5 mM, seguidas por cromatografia de troca iônica em coluna de DEAE-celulose. As frações obtidas foram concentradas por liofilização e submetidas à eletroforese em gel de agarose a 0,5%. Os ensaios anticoagulantes foram realizados pelo tempo de tromboplastina parcial ativada (TTPA), usando-se plasma de coelho e uma curva padrão de HEP (100 UI mg-1). As extrações (53,96%) mostraram diferenças marcantes durante o fracionamento e no grau de resolução dos PS. A espécie apresentou PS com atividade anticoagulante superior a HEP. O TTPA das frações modificou-se acentuadamente entre as extrações, expressando-se de maneira dose-dependente e sofrendo um acréscimo de 110,40 (1a extração) para 143,10 UI mg-1 (3a extração). Os resultados sugerem que a atividade anticoagulante dos PS isolados de Halymenia sp. foi promovida pela inibição da via intrínseca e/ou comum da cascata de coagulação. As modificações no TTPA possivelmente serão elucidadas pelos mecanismos de ação envolvidos na coagulação e caracterização estrutural desses compostos. Portanto, a rodofícea Halymenia sp. é uma boa fonte de heparinoides e sugerem-se estudos relacionados ao cultivo da espécie, em proteção aos bancos de algas.

The increasing demand for heparin (HEP) has led to a search for alternative sources of natural anticoagulants. This study aimed to evaluate the anticoagulant activity of sulfated polysaccharides (SP) isolated from a Halymenia rhodophyceae genus native to the coast of Ceará, Brazil. Total SP were obtained by consecutive digestions with papain in 0.1 M sodium acetate buffer (pH 5.0) containing 5 mM cysteine and 5 mM EDTA, followed by ion-exchange chromatography on DEAE-cellulose column. The obtained fractions were concentrated by lyophilization and submitted to 0.5% agarose gel electrophoresis. Anticoagulant activity was evaluated by the activated partial thromboplastin time (APTT) using plasma from rabbits and a standard HEP (100 IU mg-1) curve. The extractions (53.96%) showed marked differences during the fractionation and in the degree of purification of SP. The species SP showed higher activity anticoagulant than that of HEP. However, the APTT of the fractions changed sharply among the extractions, expressing itself in a dose-dependent manner and increasing from 110.40 (1st extraction) to 143.10 IU mg-1 (3rd extraction). The results suggest that the anticoagulant activity of SP isolated from Halymenia sp. was promoted by inhibition of the intrinsic and/or common pathway of the coagulation cascade. The changes on APTT possibly will be elucidated through the mechanisms of action involved in coagulation and structural characterization of these compounds. Therefore, the red alga Halymenia sp. is a good source of heparinoids, and studies are suggested on the cultivation of this species and on the protection of natural algae banks.

Assuntos

RESUMO

A crescente carência de heparina (HEP) motiva a busca por fontes alternativas de novos anticoagulantes naturais. Objetivou-se avaliar a atividade anticoagulante dos polissacarídeos sulfatados (PS) isolados de uma rodofícea do gênero Halymenia, nativa do litoral cearense, Brasil. Os PS totais foram obtidos por digestões consecutivas com papaína em tampão acetato de sódio 0,1 M (pH 5,0), contendo cisteína 5 mM e EDTA 5 mM, seguidas por cromatografia de troca iônica em coluna de DEAE-celulose. As frações obtidas foram concentradas por liofilização e submetidas à eletroforese em gel de agarose a 0,5%. Os ensaios anticoagulantes foram realizados pelo tempo de tromboplastina parcial ativada (TTPA), usando-se plasma de coelho e uma curva padrão de HEP (100 UI mg-1). As extrações (53,96%) mostraram diferenças marcantes durante o fracionamento e no grau de resolução dos PS. A espécie apresentou PS com atividade anticoagulante superior a HEP. O TTPA das frações modificou-se acentuadamente entre as extrações, expressando-se de maneira dose-dependente e sofrendo um acréscimo de 110,40 (1a extração) para 143,10 UI mg-1 (3a extração). Os resultados sugerem que a atividade anticoagulante dos PS isolados de Halymenia sp. foi promovida pela inibição da via intrínseca e/ou comum da cascata de coagulação. As modificações no TTPA possivelmente serão elucidadas pelos mecanismos de ação envolvidos na coagulação e caracterização estrutural desses compostos. Portanto, a rodofícea Halymenia sp. é uma boa fonte de heparinoides e sugerem-se estudos relacionados ao cultivo da espécie, em proteção aos bancos de algas.(AU)

The increasing demand for heparin (HEP) has led to a search for alternative sources of natural anticoagulants. This study aimed to evaluate the anticoagulant activity of sulfated polysaccharides (SP) isolated from a Halymenia rhodophyceae genus native to the coast of Ceará, Brazil. Total SP were obtained by consecutive digestions with papain in 0.1 M sodium acetate buffer (pH 5.0) containing 5 mM cysteine and 5 mM EDTA, followed by ion-exchange chromatography on DEAE-cellulose column. The obtained fractions were concentrated by lyophilization and submitted to 0.5% agarose gel electrophoresis. Anticoagulant activity was evaluated by the activated partial thromboplastin time (APTT) using plasma from rabbits and a standard HEP (100 IU mg-1) curve. The extractions (53.96%) showed marked differences during the fractionation and in the degree of purification of SP. The species SP showed higher activity anticoagulant than that of HEP. However, the APTT of the fractions changed sharply among the extractions, expressing itself in a dose-dependent manner and increasing from 110.40 (1st extraction) to 143.10 IU mg-1 (3rd extraction). The results suggest that the anticoagulant activity of SP isolated from Halymenia sp. was promoted by inhibition of the intrinsic and/or common pathway of the coagulation cascade. The changes on APTT possibly will be elucidated through the mechanisms of action involved in coagulation and structural characterization of these compounds. Therefore, the red alga Halymenia sp. is a good source of heparinoids, and studies are suggested on the cultivation of this species and on the protection of natural algae banks.(AU)

Assuntos