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Gross Chemical Profile and Calculation of Nitrogen-to-Protein Conversion Factors for Five Tropical Seaweeds

American Journal of Plant Sciences 2011年第3期2卷 287-296页

作者： Graciela S.Diniz Elisabete Barbarino João oiano-Neto Sidney Pacheco sergio o.lourenco Departamento de Biologia Marinha Universidade Federal FluminenseNiteróiBrazil Laboratório de Cromatografia Líquida Embrapa Agroindústria de AlimentosRio de JaneiroBrazil Instituto Virtual Internacional de Mudanças Globais Universidade Federal do Rio de Janeiro—UFRJ/IVIGRio de JaneiroBrazil

Despite decades of research on marine algae, there are still significant gaps in basic knowledge about chemical composition of these organisms, especially in tropical environments. In this study, the amino acid composition and contents of total nitrogen, phosphorus, lipid, carbohydrate and protein were determined in Asparagopsis taxiformis, Centroceras clavulatum, Chaetomorpha aerea, Sargassum filipendula and Spyridia hypnoides. The seaweeds showed low lipid contents (lower than 5.5% d.w. in all species) and were rich in carbohydrates (more than 16% d.w. in all seaweeds). The percentage of nitrogen, phosphorus and protein varied widely among species, which red algae showed the highest con-centrations. The amino acid composition was similar among the seaweeds, which glutamic acid, aspartic acid and leu-cine as the most abundant. All species are poor in histidine. An average of 24.2% of the total nitrogen is non-proteinaceous. From data of total amino acid and total nitrogen, specific nitrogen-to-protein conversion factors were calculated for each species. The nitrogen-to-protein conversion factors calculated ranged from 4.51 to 5.21, with an overall average of 4.86. These findings show that the traditional conversion factor of 6.25 should be avoided for seaweeds, since it overestimates the actual protein content.

关键词： Nitrogen-to-Protein Conversion Factors Protein Amino Acid Seaweeds Element Composition Tropical Environment

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Estimation of Natural Gas Production,Import and Consumption in Brazil Based on Three Mathematical Models

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Natural Resources 2012年第2期3卷 42-47页

作者： Antonio Carlos Gracias sergio Ricardo.lourenco Marat Rafikov Engineering Modeling and Applied Social Sciences Center(CECS)Federal University of ABCSanto AndreBrazil Department of Mathematics University Center of FEISao Bernardo do CampoBrazil

A mathematical model capable of providing a forecast of future consumption and import of natural gas is essential for the planning of the Brazilian energy matrix. The aim of this study is to compare three mathematical models, logistic model or model of Verhulst, exponential model or the model of Malthus and the model of von Bertalanffy to analyze the possibilities of these models to describe the evolution of production, import and consumption of natural gas in Brazil, from data provided by the energy balance of the Ministry of Mines and Energy (MME) from 1970 to 2009. A projection of the production and the import of natural gas up to 2017 is made with the models studied in this article and compared with the Brazilian Ten-Year Plan for Expansion of Energy (PDE). At the end of this paper a comparison with the Hubbert model for Brazilian natural gas production is made. These data were adjusted to use the differential equations which describe the models of population growth. All the computer work used in this article: graphics, resolution of differential equations, calculations of linearization and the least squares fitting was prepared in the software MatLab. The results obtained by means of graphs show that the population dynamics models (logistic, exponential and von Bertalanffy) can be applied in modeling the production, import and consumption of natural gas in Brazil.

关键词： Natural Gas Mathematical Modeling Logistic Model Exponential Model Model of Von Bertalanffy

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Temporal Variations of the Chemical Composition of Three Seaweeds in Two Tropical Coastal Environments

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open Journal of Marine Science 2014年第2期4卷 118-139页

作者： Andyara Nascimento Carina Coelho-Gomes Elisabete Barbarino sergio oliveira lourenco Department of Marine Biology Fluminense Federal UniversityNiteroiBrazil Maria Thereza College NiteroiBrazil Post-Graduate Programme in Chemistry Fluminense Federal UniversityNiteroiBrazil

The seaweeds Chaetomorpha antennina, Gymnogongrus griffithsiae and Ulva fasciata were studied regarding tissue concentrations of total nitrogen, total phosphorus, total protein, hydrosoluble protein, total carbohydrate, chlorophyll a and total carotenoid throughout a 39-month survey in two coastal environments of Rio de Janeiro State, Brazil. one of the sites (Itapuca Stone) has high concentrations of dissolved nutrients and an intense long-term process of cultural eutrophication;the second site (Bananal Inlet) is thought to have lower concentrations of dissolved nutrients and no relevant anthropic impact. Seaweeds experienced changes in the concentrations of the substances in the thalli;however they did not show any cyclic seasonal pattern, except for pigments, with lower values in summer in both sites. The differences found for each species in each sampling at the sites were small (e.g. U. fasciata, more total nitrogen at Itapuca Stone) or absent (e.g. C. antennina, no significant differences for hydrosoluble protein in the sites). Differences in the concentrations of dissolved nutrients in the sites did not generate contrasting chemical profiles in the seaweeds. There is no evidence of nitrogen- or phosphorus-limitation in any season. It is presumable that the concentrations of dissolved nutrients at the nutrient-poorer site are sufficient to generate high concentrations of the substances in the thalli of the species tested, similar to the concentrations measured in the eutrophic site. Experimental data are needed to elucidate the factors that promote the success of the species tested under contrasting nutrient availability and environmental disturbance.

关键词： Chemical Composition Coastal Environments Dissolved Nutrients Seaweeds Temporal Variations

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