567 research outputs found

    Influence of residual ethanol concentration on the growth of Gluconacetobacter xylinus I2281

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    The influence of residual ethanol on metabolism of food grade Gluconacetobacter xylinus I2281 was investigated during controlled cultivations on 35g/l glucose and 5g/l ethanol. Bacterial growth was strongly reduced in the presence of ethanol, which is unusual for acetic acid bacteria. Biomass accumulated only after complete oxidation of ethanol to acetate and carbon dioxide. In contrast, bacterial growth initiated without delay on 35g/l glucose and 5g/l acetate. It was found that acetyl CoA was activated by the acetyl coenzyme A synthetase (Acs) pathway in parallel with the phosphotransacetylase (Pta)-acetate kinase (Ack) pathway. The presence of ethanol in the culture medium strongly reduced Pta activity while Acs and Ack remained active. A carbon balance calculation showed that the overall catabolism could be divided into two independent parts: upper glycolysis linked to glucose catabolism and lower glycolysis liked to ethanol catabolism. This calculation showed that the carbon flux through the tricarboxylic cycle is lower on ethanol than on acetate. This corroborated the diminution of carbon flux through the Pta-Ack pathway due to the inhibition of Pta activity on ethano

    Parâmetros genéticos da densidade básica da madeira de Pinus caribaea var. hondurensis.

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    bitstream/CPAC-2010/30254/1/bolpd-213.pd

    Influence of residual ethanol concentration on the growth of Gluconacetobacter xylinus I 2281

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    The influence of residual ethanol on metab. of food grade Gluconacetobacter xylinum I 2281 was investigated during controlled cultivations on 35 g/l glucose and 5 g/l ethanol. Bacterial growth was strongly reduced in the presence of ethanol, which is unusual for acetic acid bacteria. Biomass accumulated only after complete oxidn. of ethanol to acetate and carbon dioxide. In contrast, bacterial growth initiated without delay on 35 g/l glucose and 5 g/l acetate. It was found that acetyl CoA was activated by the acetyl CoA synthetase (Acs) pathway in parallel with the phosphotransacetylase (Pta)-acetate kinase (Ack) pathway. The presence of ethanol in the culture medium strongly reduced Pta activity while Acs and Ack remained active. A carbon balance calcn. showed that the overall catabolism could be divided into two independent parts: upper glycolysis linked to glucose catabolism and lower glycolysis linked to ethanol catabolism. This calcn. showed that the carbon flux through the tricarboxylic cycle is lower on ethanol than on acetate. This corroborated the diminution of carbon flux through the Pta-Ack pathway due to the inhibition of Pta activity on ethanol. [on SciFinder (R)

    Clinical care recommendations for cardiologists treating adults with myotonic dystrophy

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    Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature-based evidence where available

    Clinical care recommendations for cardiologists treating adults with myotonic dystrophy

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    Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature-based evidence where available

    Dissection of DNA double-strand-break repair using novel single-molecule forceps.

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    Repairing DNA double-strand breaks (DSBs) by nonhomologous end joining (NHEJ) requires multiple proteins to recognize and bind DNA ends, process them for compatibility, and ligate them together. We constructed novel DNA substrates for single-molecule nanomanipulation, allowing us to mechanically detect, probe, and rupture in real-time DSB synapsis by specific human NHEJ components. DNA-PKcs and Ku allow DNA end synapsis on the 100 ms timescale, and the addition of PAXX extends this lifetime to ~2 s. Further addition of XRCC4, XLF and ligase IV results in minute-scale synapsis and leads to robust repair of both strands of the nanomanipulated DNA. The energetic contribution of the different components to synaptic stability is typically on the scale of a few kilocalories per mole. Our results define assembly rules for NHEJ machinery and unveil the importance of weak interactions, rapidly ruptured even at sub-picoNewton forces, in regulating this multicomponent chemomechanical system for genome integrity

    Doenças do pequizeiro.

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    O pequizeiro (Caryocar spp.) é uma árvore frutífera nativa dos biomas Cerrado, Caatinga, Mata Atlântica, Amazônia e Pantanal. Seus frutos são muito apreciados como alimento, mas eles também produzem ácidos graxos, que podem ser utilizados na fabricação de biocombustíveis, temperos e cos- méticos. A maior parte dos frutos comercializados ainda vem de atividades extrativistas. Quando cresce em seu ambiente natural não modificado, o pequizeiro con- vive em equilíbrio com patógenos e pragas coevoluídas. No entanto, esse equilíbrio pode estar em processo de rompimento devido aos desmatamen- tos, às queimadas frequentes, à introdução de organismos e plantas exóti- cas e atividades extrativistas predatórias, que provocam danos físicos e defi- ciências nutricionais nos pequizeiros nativos. Acredita-se que o rompimento desse equilíbrio natural vem aumentando a predisposição dos pequizeiros nativos ao ataque de várias doenças e pragas. A alta incidência de doenças em pequizeiros nativos vem preocupando agricultores, ambientalistas, extra- tivistas e outros povos que têm o pequi como fonte de renda. Essas doenças são ameaças futuras à implantação de cultivos comerciais em larga escala. Em geral, as doenças que causam a morte ou seca das árvores ou de seus galhos são as mais importantes em termos de expressão econômica. Há, também, as doenças que atacam folhas, ramos novos e frutos, que provocam queda e depreciações na qualidade dos frutos e desfolhamentos. Nesta pu- blicação, são listadas as principais doenças do pequizeiro e seus possíveis agentes etiológicos, além de medidas de controle disponíveis até o momento. Ressaltamos que inspeções sanitárias realizadas pela Embrapa, que gera- ram parte das informações relatadas neste trabalho, foram realizadas antes de 2000. Sebastiã

    Echinoderms have bilateral tendencies

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    Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present
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