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1.
Biochem J ; 454(2): 227-37, 2013 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-23763276

RESUMEN

In Saccharomyces cerevisiae, synthesis of T6P (trehalose 6-phosphate) is essential for growth on most fermentable carbon sources. In the present study, the metabolic response to glucose was analysed in mutants with different capacities to accumulate T6P. A mutant carrying a deletion in the T6P synthase encoding gene, TPS1, which had no measurable T6P, exhibited impaired ethanol production, showed diminished plasma membrane H⁺-ATPase activation, and became rapidly depleted of nearly all adenine nucleotides which were irreversibly converted into inosine. Deletion of the AMP deaminase encoding gene, AMD1, in the tps1 strain prevented inosine formation, but did not rescue energy balance or growth on glucose. Neither the 90%-reduced T6P content observed in a tps1 mutant expressing the Tps1 protein from Yarrowia lipolytica, nor the hyperaccumulation of T6P in the tps2 mutant had significant effects on fermentation rates, growth on fermentable carbon sources or plasma membrane H⁺-ATPase activation. However, intracellular metabolite dynamics and pH homoeostasis were strongly affected by changes in T6P concentrations. Hyperaccumulation of T6P in the tps2 mutant caused an increase in cytosolic pH and strongly reduced growth rates on non-fermentable carbon sources, emphasizing the crucial role of the trehalose pathway in the regulation of respiratory and fermentative metabolism.


Asunto(s)
AMP Desaminasa/metabolismo , Glucosiltransferasas/metabolismo , Mutación , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Fosfatos de Azúcar/metabolismo , Trehalosa/análogos & derivados , AMP Desaminasa/genética , Nucleótidos de Adenina/metabolismo , Membrana Celular/enzimología , Membrana Celular/metabolismo , Regulación hacia Abajo , Etanol/metabolismo , Fermentación , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glucosa/metabolismo , Glucosiltransferasas/genética , Glucólisis , Concentración de Iones de Hidrógeno , Inosina/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , ATPasas de Translocación de Protón/metabolismo , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/genética , Trehalosa/metabolismo , Yarrowia/enzimología
2.
Mol Syst Biol ; 6: 344, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-20087341

RESUMEN

Respiring Saccharomyces cerevisiae cells respond to a sudden increase in glucose concentration by a pronounced drop of their adenine nucleotide content ([ATP]+[ADP]+[AMP]=[AXP]). The unknown fate of 'lost' AXP nucleotides represented a long-standing problem for the understanding of the yeast's physiological response to changing growth conditions. Transient accumulation of the purine salvage pathway intermediate, inosine, accounted for the apparent loss of adenine nucleotides. Conversion of AXPs into inosine was facilitated by AMP deaminase, Amd1, and IMP-specific 5'-nucleotidase, Isn1. Inosine recycling into the AXP pool was facilitated by purine nucleoside phosphorylase, Pnp1, and joint action of the phosphoribosyltransferases, Hpt1 and Xpt1. Analysis of changes in 24 intracellular metabolite pools during the respiro-fermentative growth transition in wild-type, amd1, isn1, and pnp1 strains revealed that only the amd1 mutant exhibited significant deviations from the wild-type behavior. Moreover, mutants that were blocked in inosine production exhibited delayed growth acceleration after glucose addition. It is proposed that interconversion of adenine nucleotides and inosine facilitates rapid and energy-cost efficient adaptation of the AXP pool size to changing environmental conditions.


Asunto(s)
Adenosina Trifosfato/metabolismo , Metabolismo Energético , Fermentación , Saccharomyces cerevisiae/metabolismo , Adaptación Fisiológica , Adenosina Difosfato/metabolismo , Adenosina Monofosfato/metabolismo , Metabolismo Energético/genética , Fermentación/genética , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Genotipo , Glucosa/metabolismo , Homeostasis , Inosina/metabolismo , Cinética , Mutación , Fenotipo , Saccharomyces cerevisiae/enzimología , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Trehalosa/metabolismo
3.
Injury ; 52(4): 679-685, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33622592

RESUMEN

INTRODUCTION: hand injuries are a common emergency mainly caused by domestic accidents or sport injuries. During the COVID-19 pandemic confinement period, with a cut off in transportation as well as in occupational and physical activities, we observed a decrease in medical and elective surgical activities but emergency cases of upper limb and hand surgery increased. MATERIALS AND METHODS: we conducted a retrospective epidemiological study to analyze two periods between the same dates in 2019 and 2020, for all the duration of the confinement period. We compared the numbers of consultations in the emergency department, elective surgeries, hand and upper limb emergency cases in our center and urgent limb surgeries in the nearby hospital. Then we compared the mechanisms and severity of injuries and the type of surgery. RESULTS: between 2019 and 2020 there was a decrease of consultations in the emergency department in our institution of 52%, a decrease of total elective surgeries of 75%, a decrease in surgeries for urgent peripheral limb injuries of 50%, whereas the hand and upper limb emergency remained stable or even increased by 4% regard to occupational and domestic accidents. There was a significant difference in the mechanism of injury with an increase of domestic accident and a decrease of occupational, road traffic and sport accidents. Severity of the injuries increased, with augmentation of the number of tissues involved and longer expected time of recovery. CONCLUSION: during the confinement period of the COVID-19 pandemic, despite an important reduction of medical activities, the amount and severity of hand emergency cases increased. A specific plan regarding duty shift organization for hand trauma should be maintained regardless of the sanitary situation.


Asunto(s)
COVID-19 , Traumatismos de la Mano , Traumatismos de la Mano/epidemiología , Traumatismos de la Mano/cirugía , Humanos , Pandemias , Estudios Retrospectivos
4.
FEMS Yeast Res ; 9(4): 535-51, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19341380

RESUMEN

Maintenance and adaptation of energy metabolism could play an important role in the cellular ability to respond to DNA damage. A large number of studies suggest that the sensitivity of cells to oxidants and oxidative stress depends on the activity of cellular metabolism and is dependent on the glucose concentration. In fact, yeast cells that utilize fermentative carbon sources and hence rely mainly on glycolysis for energy appear to be more sensitive to oxidative stress. Here we show that treatment of the yeast Saccharomyces cerevisiae growing on a glucose-rich medium with the DNA alkylating agent methyl methanesulphonate (MMS) triggers a rapid inhibition of respiration and enhances reactive oxygen species (ROS) production, which is accompanied by a strong suppression of glycolysis. Further, diminished activity of pyruvate kinase and glyceraldehyde-3-phosphate dehydrogenase upon MMS treatment leads to a diversion of glucose carbon to glycerol, trehalose and glycogen accumulation and an increased flux through the pentose-phosphate pathway. Such conditions finally result in a significant decline in the ATP level and energy charge. These effects are dependent on the glucose concentration in the medium. Our results clearly demonstrate that calorie restriction reduces MMS toxicity through increased respiration and reduced ROS accumulation, enhancing the survival and recovery of cells.


Asunto(s)
Daño del ADN , Glucosa/metabolismo , Metilmetanosulfonato/toxicidad , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/fisiología , Estrés Fisiológico , Adenosina Trifosfato/metabolismo , Respiración de la Célula/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Gliceraldehído-3-Fosfato Deshidrogenasas/metabolismo , Glicerol/metabolismo , Glucógeno/metabolismo , Glucólisis/efectos de los fármacos , Viabilidad Microbiana , Piruvato Quinasa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Trehalosa/metabolismo
5.
J Agric Food Chem ; 58(3): 1800-3, 2010 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-20030327

RESUMEN

Two new pale yellow metabolites have been isolated from commercially available Chinese food additive Red Monascus Pigment and from Monascus ruber culture broth. They were isolated by successive TLC and semipreparative HPLC. Their structural characterization was elucidated by a variety of spectroscopic techniques (UV, IR, NMR) and mass spectrometry. These two new metabolites present numerous similarities with monascorubrin and rubropunctatin, differing in their structure only by the absence of the lactone ring. High-resolution mass spectrometry indicated the molecular formulas C(20)H(26)O(4) and C(22)H(30)O(4). The new compounds, named monarubrin and rubropunctin, contain a propenyl group on a pyrone ring, an alkyl side chain, but no gamma-lactone ring. The new metabolites have the property of producing strong blue fluorescence at 340 nm.


Asunto(s)
Monascus/química , Monascus/metabolismo , Pigmentos Biológicos/química , Pigmentos Biológicos/aislamiento & purificación , Estructura Molecular , Pigmentos Biológicos/metabolismo
6.
Yeast ; 24(1): 47-60, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17192850

RESUMEN

In this study we have revised our original procedure of yeast metabolites extraction. We showed that: (a) less than 5% of intracellular metabolites leaks out during the step of rapid arrest of cellular metabolism by quenching yeast cells into a 60% methanol solution kept at -40 degrees C; and (b) with a few exception, the stability of metabolites were not altered during the 3 min boiling procedure in a buffered ethanol solution. However, there was a loss of external added metabolites of 5-30%, depending on the type of metabolites. This was mainly attributable to their retention on cellular debris after ethanol treatment, which prevented centrifugation of the cellular extracts before evaporation of ethanol. We further simplified our previous high-performance ionic chromatography (HPIC) techniques for easier, more reliable and robust quantitative measurements of organic acids, sugar phosphates and sugar nucleotides, and extended these techniques to purine and pyrimidine bases, using a variable wavelength detector set at 220 and 260 nm in tandem with a pulsed electrochemical or suppressed conductivity detector. These protocols were successfully applied to a glucose pulse to carbon-limited yeast cultures on purines metabolism. This study showed that glucose induced a fast activation of the purine salvage pathway, as indicated by a transient drop of ATP and ADP with a concomitant rise of IMP and inosine. This metabolic perturbation was accompanied by a rapid increase in the activity of the ISN1-encoded specific IMP-5'-nucleotidase. The mechanism of this activation remains to be determined.


Asunto(s)
Glucosa/metabolismo , Saccharomyces cerevisiae/química , Nucleótidos de Adenina/análisis , Métodos Analíticos de la Preparación de la Muestra , Fructosafosfatos/análisis , Fumaratos/análisis , Glucosa-6-Fosfato/análisis , Glucofosfatos/análisis , Inosina/análisis , Inosina Monofosfato/análisis , Ácido Pirúvico/análisis , Saccharomyces cerevisiae/metabolismo , Fosfatos de Azúcar/análisis , Trehalosa/análogos & derivados , Trehalosa/análisis
7.
FEMS Yeast Res ; 7(1): 22-32, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17005001

RESUMEN

Saccharomyces cerevisiae was able to produce 20% (v/v) of ethanol in 45 h in a fully aerated fed-batch process recently developed in our laboratory. A notable feature of this process was a production phase uncoupled to growth, the extent of which was critical for high-level ethanol production. As the level of production was found to be highly variable, we investigated on this high variability by means of a detailed physiological analysis of yeast cells in two fed-batch fermentations showing the most extreme behaviour. We found a massive leakage of intracellular metabolites into the growth medium which correlated with the drop of cell viability. The loss of viability was also found to be proportional to the reduction of plasma membrane phospholipids. Finally, the fed-batch processes with the longest uncoupling phase were characterized by induction of storage carbohydrates at the onset of this phase, whereas this metabolic event was not seen in processes with a short uncoupling phase. Taken together, our results suggested that reproducible high-level bioethanol production in aerated fed-batch processes may be linked to the ability of yeast cells to impede ethanol toxicity by triggering a metabolic remodelling reminiscent to that of cells entering a quiescent GO/G1 state.


Asunto(s)
Adaptación Fisiológica , Reactores Biológicos , Etanol/metabolismo , Saccharomyces cerevisiae/fisiología , Aerobiosis , Medios de Cultivo , Fermentación , Regulación Fúngica de la Expresión Génica , Microbiología Industrial/métodos , Saccharomyces cerevisiae/crecimiento & desarrollo , Saccharomyces cerevisiae/metabolismo
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