Determination of Starch and Cellulose with Anthrone

Viles, Frederick J.; Silverman, Leslie

doi:10.1021/ac60032a019

Cited by 308 publications

(109 citation statements)

References 6 publications

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“…The L-lactate dehydrogenase family includes both LDH and malate dehydrogenase (MDH; EC 1.1.1.37) enzymes, which are structurally similar and use the same coenzyme (NADH) to catalyze a redox interconversion by similar mechanisms. It has been demonstrated experimentally that the substitution of a single amino acid at position 86 can change the substrate binding specifi city from lactate to malate [29], and it is therefore common for these genes to be misannotated when analyzed solely on the basis of sequence homology.…”

Section: Discussionmentioning

confidence: 99%

Pyruvate catabolism and hydrogen synthesis pathway genes of Clostridium thermocellum ATCC 27405

et al. 2008

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Clostridium thermocellum is a gram-positive, acetogenic, thermophilic, anaerobic bacterium that degrades cellulose and carries out mixed product fermentation, catabolising cellulose to acetate, lactate, and ethanol under various growth conditions, with the concomitant release of H 2 and CO 2 . Very little is known about the factors that determine metabolic fl uxes infl uencing H 2 synthesis in anaerobic, cellulolytic bacteria like C. thermocellum. We have begun to investigate the relationships between genome content, gene expression, and end-product synthesis in C. thermocellum cultured under different conditions. Using bioinformatics tools and the complete C. thermocellum 27405 genome sequence, we identifi ed genes encoding key enzymes in pyruvate catabolism and H 2 -synthesis pathways, and have confi rmed transcription of these genes throughout growth on α-cellulose by reverse transcriptase polymerase chain reaction. Bioinformatic analyses revealed two putative lactate dehydrogenases, one pyruvate formate lyase, four pyruvate:formate lyase activating enzymes, and at least three putative pyruvate:ferredoxin oxidoreductase (POR) or POR-like enzymes. Our data suggests that hydrogen may be generated through the action of either a Ferredoxin (Fd)-dependent NiFe hydrogenase, often referred to as "Energy-converting Hydrogenases", or via NAD(P)Hdependent Fe-only hydrogenases which would permit H 2 production from NADH generated during the glyceraldehyde-3-phosphate dehydrogenase reaction. Furthermore, our fi ndings show the presence of a gene cluster putatively encoding a membrane integral NADH:Fd oxidoreductase, suggesting a possible mechanism in which electrons could be transferred between NADH and ferredoxin. The elucidation of pyruvate catabolism pathways and mechanisms of H 2 synthesis is the fi rst step in developing strategies to increase hydrogen yields from biomass. Our studies have outlined the likely pathways leading to hydrogen synthesis in C. thermocellum strain 27405, but the actual functional roles of these gene products during pyruvate catabolism and in H 2 synthesis remain to be elucidated, and will need to be confi rmed using both expression analysis and protein characterization.

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Section: Discussionmentioning

confidence: 99%

Pyruvate catabolism and hydrogen synthesis pathway genes of Clostridium thermocellum ATCC 27405

et al. 2008

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“…Para fins comparativos, outros dois métodos de mensuração da lignina foram conduzidos, o método da lignina em detergente ácido -LDA ( V A N S O E S T , 1 9 6 3 ) e o d a l i g n i n a e m permanganato de potássio -LPer ( VAN SOEST e WINE, 1968), ambos procedimentos analíticos de natureza gravimétrica. As determinações de proteína bruta nas amostras de LBrAc seguiram os preceitos da AOAC (1980) e as determinações de carboidrato, a técnica da antrona, descrita por VILES JR. e SILVERMAN (1949).…”

Section: Methodsunclassified

Extração da lignina e emprego da mesma em curvas de calibração para a mensuração da lignina em produtos vegetais

et al. 2000

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RESUMO -O objetivo deste experimento foi a extração da lignina e seu uso nas curvas de calibração para determinar a concentração de lignina em produtos vegetais. Dentre os métodos analíticos utilizados para a mensuração da lignina, pode-se mencionar o método "lignina solúvel em brometo de acetila -LSBA", no qual a lignina é solubilizada em uma solução de brometo de acetila a 25% em ácido acético glacial e, depois, lida no comprimento de onda a 280 nm. Entretanto, todo método espectrofotométrico requer o emprego de um padrão de referência confiável; neste experimento utilizou-se como padrão de referência a lignina da planta forrageira extraída com o emprego do próprio brometo de acetila. Quantificou-se a lignina presente em quatro amostras de forrageiras, em dois estádios de maturidade e, ainda, em duas amostras de madeiras, comparando-se os dados com outros dois métodos de determinação da lignina (lignina em detergente ácido -LDA e lignina permanganato de potássio -LPer). Os três métodos não foram concordantes entre si, sendo que, para praticamente todas as amostras, o método da LSBA mostrou valores mais elevados que os outros dois métodos. Para cada amostra analisada, foram confeccionados uma curva-padrão e um espectrograma na faixa de comprimento de luz de 240 a 320 nm. A análise dessas curvas e dos espectrogramas indicou diferenças qualitativas entre as amostras, em função não apenas da espécie botânica, mas também do estádio de maturidade da planta.Palavras-chave: análise química, espectrofotometria, lignina, plantas forrageiras Lignin Extraction and its Performance in Calibration Curves to Determine Lignin Concentration in PlantsABSTRACT -The objective of this experiment was the extraction of lignin and its use in the calibration curves to determine lignin concentration in vegetable plants. Among the analytical methods for measuring lignin concentration, there is the "acetyl bromide soluble lignin -ABSL" method, were solubilized lignin in 25% solution of acetyl bromide in glacial acetic acid is read at 280 nm. However, any spectrophotometric method requires a reliable standard to which optical density readings are compared; in this experiment, the standard was obtained through extraction with acetyl bromide reagent. Lignin was quantified in four forage samples, at two maturity stages, and also in two wood samples, comparing the obtained data with two other analytical methods for lignin (acid detergent lignin -ADL and potassium permanganate lignin -PerL). The three techniques yielded different values for the same samples; in general, the ABSL method showed higher lignin concentrations than the two other methods. For each sample it was made a standard curve and a 240-320 nm ultraviolet scanning. Analyses of such curves and scannings indicated qualitative differences among samples, not only related to plant species, but also to maturity stage of vegetable samples.Key Words: chemical analysis, forages, lignin, spectrophotometric analysis Rev. bras. zootec., 29(5):1302-1311, 2000Introdução A lignina é um compone...

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“…Protein was determined using the modified Lowry method (Shakir et al 1994), glycogen using the anthrone reagent (Viles and Silverman 1949), and total lipids were extracted from fresh homogenized material in chloroform/methanol (Folch et al 1957) and estimated spectrophotometrically after charring with concentrated sulphuric acid (Marsh and Weinstein 1966). All values are expressed as μg mg -1 of dry weight (dw).…”

Section: Biochemical Parametersmentioning

confidence: 99%

Enhanced trace element concentrations in tissues of the clam <em>Ruditapes decussatus</em> transplanted to areas influenced by human activities (Ria Formosa, Portugal)

et al. 2017

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Summary:To examine the extent to which human activities near the Ria Formosa coastal lagoon influence the accumulation of trace elements (TE) in Ruditapes decussatus, individuals were transplanted from a natural bank located in the lower lagoon to three sites located in clam growth grounds under the influence of a small city (Faro), a fish farming centre (Olhão) and a site near the lagoon inlet (Lavajo). Concentrations were determined in substrate of the clam grounds and in the digestive gland, gills, mantle plus siphons, and remaining tissues of clams in four periods of the year. These measurements were accomplished with the monthly survey of the gametogenic stages, condition index, proteins, glycogen, total lipids, pH and osmolarity of hemolymph. Arsenic, Cu, Mn, V, Cr and Pb were preferentially linked to the digestive gland, while Cd was linked to the gills. TE concentrations in the digestive gland and remaining tissues were higher in winter, most likely reflecting additional inputs associated with rain. The lack of disruptions in biological parameters and the prolonged period of spawning and gonad recovery in clams suggest that the current TE availability in the lagoon has a minor influence on the reproductive cycle and hence on clam production. Keywords: trace elements; biological parameters; Ruditapes decussatus; Ria Formosa. Aumento de la concentración de elementos traza en tejidos de la almeja Ruditapes decussatus trasplantada a zonas influenciadas por actividades humanas (ría Formosa, Portugal)Resumen: Para examinar en qué medida las actividades humanas cercanas a la laguna costera ría Formosa influyen en la acumulación de elementos traza (ET) en Ruditapes decussatus, se trasplantaron individuos desde un banco natural situado en la parte baja de la laguna a tres sitios localizados en zonas de cultivo de almejas bajo la influencia de una ciudad pequeña (Faro), un centro piscícola (Olhão) y cerca de la entrada de una laguna (Lavajo). Se determinaron las concentraciones de ET en el substrato de locales y en la glándula digestiva, branquias, manto más sifones, y en los tejidos restantes de las almejas en cuatro períodos a lo largo de un año. Estas mediciones fueron realizadas con el estudio mensual de las etapas gametógenas, índice de condición, proteínas, glicóneo, lípidos totales, pH y osmolaridad de la hemolinfa. El As, Cu, Mn, V, Cr y Pb fueron relacionados preferencialmente a la glándula digestiva, mientras que el Cd fue a las branquias. La concentración de ET en la glándula digestiva y los tejidos restantes fue más elevada en invierno, probablemente reflejando los aportes adicionales asociados con la lluvia. La falta de alteraciones de los parámetros biológicos, el período prolongado de desove y la recuperación de las gónadas en las almejas sugieren que la disponibilidad actual de ET en la laguna tienen una influencia menor durante el ciclo reproductivo y, por lo tanto, en la producción de almejas.

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Determination of Starch and Cellulose with Anthrone

Cited by 308 publications

References 6 publications

Pyruvate catabolism and hydrogen synthesis pathway genes of Clostridium thermocellum ATCC 27405

Pyruvate catabolism and hydrogen synthesis pathway genes of Clostridium thermocellum ATCC 27405

Extração da lignina e emprego da mesma em curvas de calibração para a mensuração da lignina em produtos vegetais

Enhanced trace element concentrations in tissues of the clam <em>Ruditapes decussatus</em> transplanted to areas influenced by human activities (Ria Formosa, Portugal)

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