RESUMO
Ulvans are complex sulfated polysaccharides found in the cell walls of green algae belonging to the genus Ulva. These polysaccharides are composed of disaccharide repetition moieties made up of sulfated rhamnose linked to either glucuronic acid, iduronic acid, or xylose. Two ulvan lyases of 30 and 46 kDa were purified from the culture supernatant of Persicivirga ulvanivorans. Based on peptide sequencing, the gene encoding the 46-kDa ulvan lyase was cloned. Sequence analysis revealed that the protein is modular and possesses a catalytic module similar to that of the 30-kDa ulvan lyase along with a module of unknown function. The ulvan-degrading function of the gene was confirmed by expression of the catalytic module in a heterologous system. The gene encoding the catalytic module has no sequence homolog in sequence databases and is likely to be the first member of a novel polysaccharide lyase family. Analysis of degradation products showed that both the 30- and 46-kDa ulvan lyases are endolytic and cleave the glycosidic bond between the sulfated rhamnose and a glucuronic or iduronic acid.
Assuntos
Parede Celular/metabolismo , Clorófitas/metabolismo , Ulva/química , Sequência de Aminoácidos , Configuração de Carboidratos , Sequência de Carboidratos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida/métodos , Clonagem Molecular , Enzimas/química , Ácido Glucurônico/química , Ácido Idurônico/química , Cinética , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Peptídeos/química , Polissacarídeo-Liases/química , Espectrometria de Massas em Tandem/métodosRESUMO
The increased levels of fine particles in the atmosphere are suspected of aggravating cardiopulmonary diseases, but the determinants of particle toxicity are poorly understood. This work aims at studying the role of composition and size in the toxicity of size-segregated particulate matter (PM) collected at different sites on human bronchial epithelial cells. PM were sampled at a traffic urban site (Urb S) and a rural site (Rur S) during the pesticide-spreading period. Ultrafine (UF), fine (F), and coarse (C) PM were characterized by their shape and chemical composition. Whatever the site, the finest PM (UF and F) induced the mRNA expression of CYP1A1, a biomarker of polyaromatic hydrocarbons (PAH) exposure, NQO-1 and heme HO-1, two antioxidant responsive element-driven genes; and two effect biomarkers, GM-CSF, a proinflammatory cytokine and amphiregulin (AR), a growth factor. C PM have a low or no effect. Interestingly, AR is more strongly induced by rural PM at the same mass exposure. These discrepancies suggest involvement of PM chemical composition: rural PM bearing the characteristics of aged aerosols with a high content of water-soluble components, and PM at urban kerbside sites containing mainly water-insoluble components. To conclude, we provide evidence that the finest PM fractions, whatever their origin, are more prone to induce exposure and effect biomarkers. The AR differential expression suggests a source-dependent effect requiring further investigation because of the role of this growth factor in airway remodeling, a characteristic feature of chronic lung respiratory diseases exacerbated by particulate pollution.
Assuntos
Aerossóis/toxicidade , Agricultura , Poluentes Atmosféricos/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Mucosa Respiratória/efeitos dos fármacos , Emissões de Veículos/toxicidade , Aerossóis/química , Poluentes Atmosféricos/química , Anfirregulina , Biomarcadores/metabolismo , Linhagem Celular , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Família de Proteínas EGF , Perfilação da Expressão Gênica , Glicoproteínas/genética , Glicoproteínas/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Exposição por Inalação , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , NAD(P)H Desidrogenase (Quinona)/genética , NAD(P)H Desidrogenase (Quinona)/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Tamanho da Partícula , RNA Mensageiro/metabolismo , Mucosa Respiratória/metabolismo , Mucosa Respiratória/patologia , População Rural , População Urbana , Emissões de Veículos/análiseRESUMO
This study represents a large-scale investigation into iodine contents in three commercially important and edible seaweed species from the North Atlantic: the brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata. Variability among and within species were explored in terms of temporal and spatial variations in addition to biomass source. Mean iodine concentration in bulk seaweed biomass was species-specific: Saccharinaâ¯>â¯Alariaâ¯>â¯Palmaria. Iodine contents of Saccharina biomass were similar between years and seasons, but varied significantly between sampling locations and biomass sources. In Alaria and Palmaria, none of the independent variables examined contributed significantly to the small variations observed. Our data suggest that all three species are rich sources of iodine, and only 32, 283, or 2149â¯mg dry weight of unprocessed dry biomass of Saccharina, Alaria, or Palmaria, respectively, meets the recommended daily intake levels for most healthy humans.