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Peñaloza De La Torre, Ulises Massino - One of the best experts on this subject based on the ideXlab platform.
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Efecto del Hidróxido de Calcio-Paramonoclorofenol Alcanforado y de la Solución Hidróxido de Calcio-Yodoformo sobre el Crecimiento In Vitro de Enterococcus Faecalis. Tacna 2016
Universida Catòlica de Santa Marìa, 2018Co-Authors: Peñaloza De La Torre, Ulises MassinoAbstract:TesisLa investigación tuvo como objetivo comparar el efecto del Hidróxido de calcioparamonoclorofenol alcanforado y la solución Hidróxido de Calcio-Yodoformo sobre el crecimiento in vitro de Enterococcus faecalis. Fue una investigación experimental, que se trabajó con una cepa pura de la bacteria Enterococcus faecalis ATCC 19433, se dividió en dos grupos de estudio: el grupo experimental A: Hidróxido de calcio- paramonoclorofenol alcanforado + Enterococcus faecalis en ambiente de aerobiosis y Anaerobiosis. Grupo experimental B: Solución Hidróxido de calcio – Yodoformo + Enterococcus faecalis en ambiente de aerobiosis y Anaerobiosis; todos diluidos en caldo cerebro corazón; con 30 réplicas para cada grupo. Para esto se aplicó la técnica de recuento en placa por el método de incorporación, repitiendo el procedimiento en los dos grupos de estudio, para luego dar lectura de las placas a los 3, 7, 14 y 21 días observando si existe crecimiento o inhibición in vitro de Enterococcus faecalis. Los resultados del estudio reportaron que el Hidróxido de calcio- paramonoclorofenol alcanforado recién a los 7 días, mostró inhibición bacteriana en condiciones de Anaerobiosis y solo desde los 14 días hasta los 21 días hubo inhibición bacteriana completa en ambas condiciones de cultivo, mientras que con la solución Hidróxido de Calcio – Yodoformo, inhibió el crecimiento bacteriano en su totalidad desde los 3 días, manteniéndose así hasta los 21días del estudio, en las dos formas ambientales aplicadas. La prueba de hipótesis se realizó mediante el estadístico prueba con lambda de Wilks, las pruebas demostraron P
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Efecto del Hidróxido de Calcio-Paramonoclorofenol Alcanforado y de la Solución Hidróxido de Calcio-Yodoformo sobre el Crecimiento In Vitro de Enterococcus Faecalis. Tacna 2016
Universida Catòlica de Santa Marìa, 2018Co-Authors: Peñaloza De La Torre, Ulises MassinoAbstract:La investigación tuvo como objetivo comparar el efecto del Hidróxido de calcioparamonoclorofenol alcanforado y la solución Hidróxido de Calcio-Yodoformo sobre el crecimiento in vitro de Enterococcus faecalis. Fue una investigación experimental, que se trabajó con una cepa pura de la bacteria Enterococcus faecalis ATCC 19433, se dividió en dos grupos de estudio: el grupo experimental A: Hidróxido de calcio- paramonoclorofenol alcanforado + Enterococcus faecalis en ambiente de aerobiosis y Anaerobiosis. Grupo experimental B: Solución Hidróxido de calcio – Yodoformo + Enterococcus faecalis en ambiente de aerobiosis y Anaerobiosis; todos diluidos en caldo cerebro corazón; con 30 réplicas para cada grupo. Para esto se aplicó la técnica de recuento en placa por el método de incorporación, repitiendo el procedimiento en los dos grupos de estudio, para luego dar lectura de las placas a los 3, 7, 14 y 21 días observando si existe crecimiento o inhibición in vitro de Enterococcus faecalis. Los resultados del estudio reportaron que el Hidróxido de calcio- paramonoclorofenol alcanforado recién a los 7 días, mostró inhibición bacteriana en condiciones de Anaerobiosis y solo desde los 14 días hasta los 21 días hubo inhibición bacteriana completa en ambas condiciones de cultivo, mientras que con la solución Hidróxido de Calcio – Yodoformo, inhibió el crecimiento bacteriano en su totalidad desde los 3 días, manteniéndose así hasta los 21días del estudio, en las dos formas ambientales aplicadas. La prueba de hipótesis se realizó mediante el estadístico prueba con lambda de Wilks, las pruebas demostraron P
Reto Strasser - One of the best experts on this subject based on the ideXlab platform.
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effects of Anaerobiosis as probed by the polyphasic chlorophyll a fluorescence rise kinetic in pea pisum sativum l
Photosynthesis Research, 1999Co-Authors: Pierre Haldimann, Reto StrasserAbstract:We analysed the changes of the chlorophyll (Chl) a fluorescence rise kinetic (from 50 μs to 1 s) that occur when leaves or chloroplasts of pea ( Pisum sativum L.) are incubated under anaerobic conditions in the dark. In control leaves, Chl a fluorescence followed a typical O-J-I-P polyphasic rise [Strasser et al. (1995) Photochem Photobiol 61: 32–42]. Anaerobiosis modified the shape of the transient with the main effect being a time-dependent increase in the fluorescence yield at the J-step (2 ms). Upon prolongation of the anaerobic treatment (> 60 min), the O-J-I-P fluorescence rise was eventually transformed to an O-J (J = P) rise. A similar transformation was observed when pea leaves were treated with DCMU or sodium dithionite. Anaerobiosis resulted in a 10–20% reduction in the maximum quantum yield of the primary photochemistry of Photosystem II, as measured by the ratio of the maximal values of variable and total fluorescence (FV/FM). When the leaves were returned to the air in the dark, the shape of the fluorescence transient showed a time-dependent recovery from the Anaerobiosis-induced change. The original O-J-I-P shape could also be restored by illuminating the anaerobically treated samples with far-red light but not with blue or white light. Osmotically broken chloroplasts displayed under anaerobic conditions fluorescence transients similar to those observed in anaerobically treated leaves, but only when they were incubated in a medium comprising reduced pyridine nucleotides (NADPH or NADH). As in intact leaves, illumination of the anaerobically treated chloroplasts by far-red light restored the original O-J-I-P transient, although only in the presence of methyl viologen. The results provide additional evidence for the existence of a chlororespiratory pathway in higher plant cells. Furthermore, they suggest that the J-level of the fluorescence transient is strongly determined by the redox state of the electron carriers at the PS II acceptor side.
Fatthy Mohamed Morsy - One of the best experts on this subject based on the ideXlab platform.
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feasibility of installing and maintaining Anaerobiosis using escherichia coli hd701 as a facultative anaerobe for hydrogen production by clostridium acetobutylicum atcc 824 from various carbohydrates
Enzyme and Microbial Technology, 2015Co-Authors: Sedky H A Hassan, Fatthy Mohamed MorsyAbstract:Using Escherichia coli for installing and maintaining Anaerobiosis for hydrogen production by Clostridium acetobutylicum ATCC 824 is a cost-effective approach for industrial hydrogen production, as it does not require reducing agents or sparging with inert gases. This study was devoted for investigating the feasibility for installing and maintaining Anaerobiosis of hydrogen production by C. acetobutylicum ATCC 824 when using E. coli HD701 utilizable versus non utilizable sugars as a-carbon source. Using E. coli HD701 for installing Anaerobiosis showed a comparable hydrogen production yield and efficiency to the use of reducing agents and nitrogen sparging in case of hydrogen production from the E. coli HD701 non utilizable sugars. In contrast, using E. coli HD701 for installing Anaerobiosis showed a lower hydrogen production yield and efficiency than the use of reducing agents and nitrogen sparging in case of using glucose as a substrate. This is possibly because E. coli HD701 when using glucose compensate for the substrate, and produce hydrogen with lower efficiency than C. acetobutylicum ATCC 824. These results indicated that the use of E. coli HD701 for installing Anaerobiosis would not be economically feasible when using E. coli HD701 utilizable sugars as a carbon source. In contrast, the use of this approach for installing Anaerobiosis for hydrogen production from sucrose and starch would have a high potency for industrial applications.
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acetate versus sulfur deprivation role in creating Anaerobiosis in light for hydrogen production by chlamydomonas reinhardtii and spirulina platensis two different organisms and two different mechanisms
Photochemistry and Photobiology, 2011Co-Authors: Fatthy Mohamed MorsyAbstract:This work was devoted to separate acetate role in creating Anaerobiosis from that of sulfur deprivation. Chlamydomonas reinhardtii grown in TAP (Tris-acetate-phosphate) medium was resuspended in sulfur-replete or -deprived medium in sealed or nonsealed cultures. Sulfur deprivation was substantial for starch accumulation and hydrogen evolution; however, acetate induced Anaerobiosis in the presence or absence of sulfur in only sealed cultures. In nonsealed cultures, Chlamydomonas did not lose its photosynthetic activity; however, it was arrested in anoxia with no photosynthetic activity as long as the culture was sealed. The sealed cultures resumed photosynthesis upon unsealing overnight unless the cells died by anoxia at late stage of the experiment. These results indicate that the enhanced oxygen consumption for the enormous acetate respiration and inhibition of the external oxygen supply in sealed cultures of Chlamydomonas are the main reasons for the steady anaerobic conditions. Although acetate was substantial for creating Anaerobiosis in Chlamydomonas, sulfur deprivation alone could create Anaerobiosis in Spirulina platensis grown autotrophically. Hydrogen evolution and glycogen accumulation were induced under such conditions. Severely reduced phycocyanin, chlorophyll and photosynthesis, while respiration had increased, induced Anaerobiosis in Spirulina. This study reports for the first time Anaerobiosis under autotrophic conditions in a cyanobacterium.
Michel Havaux - One of the best experts on this subject based on the ideXlab platform.
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cyclic electron flow around photosystem i in c 3 plants in vivo control by the redox state of chloroplasts and involvement of the nadh dehydrogenase complex
Plant Physiology, 2002Co-Authors: Thierry Joet, Laurent Cournac, Gilles Peltier, Michel HavauxAbstract:Cyclic electron flow around photosystem (PS) I has been widely described in vitro in chloroplasts or thylakoids isolated from C3 plant leaves, but its occurrence in vivo is still a matter of debate. Photoacoustic spectroscopy and kinetic spectrophotometry were used to analyze cyclic PS I activity in tobacco (Nicotiana tabacum cv Petit Havana) leaf discs illuminated with far-red light. Only a very weak activity was measured in air with both techniques. When leaf discs were placed in Anaerobiosis, a high and rapid cyclic PS I activity was measured. The maximal energy storage in far-red light increased to 30% to 50%, and the half-time of the P700 re-reduction in the dark decreased to around 400 ms; these values are comparable with those measured in cyanobacteria and C4 plant leaves in aerobiosis. The stimulatory effect of Anaerobiosis was mimicked by infiltrating leaves with inhibitors of mitochondrial respiration or of the chlororespiratory oxidase, therefore, showing that changes in the redox state of intersystem electron carriers tightly control the rate of PS I-driven cyclic electron flow in vivo. Measurements of energy storage at different modulation frequencies of far-red light showed that Anaerobiosis-induced cyclic PS I activity in leaves of a tobacco mutant deficient in the plastid Ndh complex was kinetically different from that of the wild type, the cycle being slower in the former leaves. We conclude that the Ndh complex is required for rapid electron cycling around PS I.
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cyclic electron flow around photosystem i in c3plants in vivo control by the redox state of chloroplasts andinvolvement of the nadh dehydrogenase complex
Plant Physiology, 2002Co-Authors: Thierry Joet, Laurent Cournac, Gilles Peltier, Michel HavauxAbstract:Cyclic electron flow around photosystem (PS) I has been widely described in vitro in chloroplasts or thylakoids isolated from C3 plant leaves, but its occurrence in vivo is still a matter of debate. Photoacoustic spectroscopy and kinetic spectrophotometry were used to analyze cyclic PS I activity in tobacco (Nicotiana tabacum cv Petit Havana) leaf discs illuminated with far-red light. Only a very weak activity was measured in air with both techniques. When leaf discs were placed in Anaerobiosis, a high and rapid cyclic PS I activity was measured. The maximal energy storage in far-red light increased to 30% to 50%, and the half-time of the P700 re-reduction in the dark decreased to around 400 ms; these values are comparable with those measured in cyanobacteria and C4 plant leaves in aerobiosis. The stimulatory effect of Anaerobiosis was mimicked by infiltrating leaves with inhibitors of mitochondrial respiration or of the chlororespiratory oxidase, therefore, showing that changes in the redox state of intersystem electron carriers tightly control the rate of PS I-driven cyclic electron flow in vivo. Measurements of energy storage at different modulation frequencies of far-red light showed that Anaerobiosis-induced cyclic PS I activity in leaves of a tobacco mutant deficient in the plastid Ndh complex was kinetically different from that of the wild type, the cycle being slower in the former leaves. We conclude that the Ndh complex is required for rapid electron cycling around PS I.
Benoit De Sarrau - One of the best experts on this subject based on the ideXlab platform.
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Unsaturated fatty acids from food and in the growth medium improve growth of Bacillus cereus under cold and anaerobic conditions.
Food Microbiology, 2013Co-Authors: Benoit De Sarrau, Thierry Clavel, Nicolas Zwickel, Jordane Despres, Sébastien Dupont, Laurent Beney, Raphaëlle Tourdot-maréchal, Christophe Nguyen-theAbstract:In a chemically defined medium and in Luria broth, cold strongly reduced maximal population density of Bacillus cereus ATCC 14579 in Anaerobiosis and caused formation of filaments. In cooked spinach, maximal population density of B. cereus in Anaerobiosis was the same at cold and optimal temperatures, with normal cell divisions. The lipid containing fraction of spinach, but not the hydrophilic fraction, restored growth of B. cereus under cold and Anaerobiosis when added to the chemically defined medium. This fraction was rich in unsaturated, low melting point fatty acids. Addition of phosphatidylcholine containing unsaturated, low melting point, fatty acids similarly improved B. cereus anaerobic growth at cold temperature. Addition of hydrogenated phosphatidylcholine containing saturated, high melting point, fatty acids did not modify growth. Fatty acids from phospholipids, from spinach and from hy-drogenated phosphatidylcholine, although normally very rare in B. cereus, were inserted in the bacterium membrane. Addition of phospholipids rich in unsaturated fatty acids to cold and anaerobic cultures, increased fluidity of B. cereus membrane lipids, to the same level as those from B. cereus normally cold adapted, i.e. grown aerobically at 15 C. B. cereus is therefore able to use external fatty acids from foods or from the growth medium to adapt its membrane to cold temperature under Anaerobiosis, and to recover the maximal population density achieved at optimal temperature.
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influence of Anaerobiosis and low temperature on bacillus cereus growth metabolism and membrane properties
Applied and Environmental Microbiology, 2012Co-Authors: Benoit De Sarrau, Thierry Clavel, Caroline Clerte, Frederic Carlin, Christian Ginies, Christophe NguyentheAbstract:ABSTRACT The impact of simultaneous Anaerobiosis and low temperature on growth parameters, metabolism, and membrane properties of Bacillus cereus ATCC 14579 was studied. No growth was observed under Anaerobiosis at 12°C. In bioreactors, growth rates and biomass production were drastically reduced by simultaneous Anaerobiosis and low temperature (15°C). The two conditions had a synergistic effect on biomass reduction. In anaerobic cultures, fermentative metabolism was modified by low temperature, with a marked reduction in ethanol production leading to a lower ability to produce NAD + . Anaerobiosis reduced unsaturated fatty acids at both low optimal temperatures. In addition, simultaneous Anaerobiosis and low temperatures markedly reduced levels of branched-chain fatty acids compared to all other conditions (accounting for 33% of total fatty acids against more 71% for low-temperature aerobiosis, optimal-temperature aerobiosis, and optimal-temperature Anaerobiosis). This corresponded to high-melting-temperature lipids and to low-fluidity membranes, as indicated by differential scanning calorimetry, 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy, and infrared spectroscopy. This is in contrast to requirements for cold adaptation. A link between modification in the synthesis of metabolites of fermentative metabolism and the reduction of branched-chain fatty acids at low temperature under Anaerobiosis, through a modification of the oxidizing capacity, is assumed. This link may partly explain the impact of low temperature and Anaerobiosis on membrane properties and growth performance.