RESUMO
OBJECTIVE: To analyze the evolution of sepsis-related mortality in Spanish Intensive Care Units (ICUs) following introduction of the Surviving Sepsis Campaign (SSC) guidelines and the relationship with sepsis process-of-care. DESIGN: A prospective cohort study was carried out, with the inclusion of all consecutive patients presenting severe sepsis or septic shock admitted to 41 Spanish ICUs during two time periods: 2005 (Edusepsis study pre-intervention group) and 2011 (ABISS-Edusepsis study pre-intervention group). Scope: Patients with severe sepsis or septic shock admitted to Spanish ICUs. PATIENTS: All ICU admissions from the emergency department or wards and all ICU patients with a diagnosis of severe sepsis or septic shock. A total of 1348 patients were included: 630 in the 2005 group and 718 in the 2011 group. Intervention: None. Primary endpoints: ICU mortality, 28-day mortality and Hospital mortality, hospital length of stay, ICU length of stay and compliance with the resuscitation bundle. RESULTS: Compliance with the resuscitation bundle was significantly greater in the 2011 group (5.7% vs. 9.9%; p = 0.005), and was associated to lower mortality (OR 0.602 [0.365-0.994]; p = 0.048). The 2011 group had lower absolute in-hospital mortality (44.0% vs. 32.6%; p = 0.01), 28-day mortality (36.5% vs. 23.0%; p = 0.01), and adjusted mortality (OR 0.64 [0.49-0.83], p = 0.001). CONCLUSIONS: Mortality related to severe sepsis or septic shock in Spain decreased between two patient cohorts in 2005 and 2011, and was attributable to earliness and improvement in sepsis care
OBJETIVO: Analizar la evolución de la mortalidad relacionada con la sepsis en las unidades de cuidados intensivos (UCI) españolas desde la introducción de las directrices Surviving Sepsis Campaing y la relación con el proceso de atención de la sepsis. DISEÑO: Estudio prospectivo de cohortes. Se incluyeron de manera consecutiva, todos los pacientes con sepsis grave o shock séptico ingresados en 41 UCI españolas durante 2 periodos de tiempo: en 2005 (grupo pre-intervención en el estudio Edusepsis) y en 2011 (grupo pre-intervención en el estudio ABISS-Edusepsis). Ámbito: Pacientes con sepsis grave o shock séptico ingresados en las UCI españolas. PACIENTES: Todos los ingresos en UCI procedentes de Urgencias o planta y todos los pacientes de UCI con diagnóstico de sepsis grave/shock séptico. Se incluyeron 1348 pacientes: 630 del grupo de 2005 y 718 del grupo de 2011. Intervención: Ninguna. Variables de interés principal: Mortalidad en UCI, a 28 días y hospitalaria, estancia en la UCI y en el hospital y cumplimiento con el bundle de reanimación. RESULTADOS: El cumplimiento del bundle de reanimación fue significativamente mayor en el grupo de 2011 (5,7 frente a 9,9%, p = 0,005) y se asoció con una menor mortalidad (OR 0,602 [0,365 a 0,994], p = 0,048). El grupo de 2011 tuvo una menor mortalidad absoluta hospitalaria (44,0 frente a 32,6%, p = 0,01), mortalidad a los 28 días (36,5 frente a 23,0%, p = 0,01) y mortalidad ajustada (OR 0,64 [0,49 a 0,83], p = 0,001). CONCLUSIONES: La mortalidad relacionada con la sepsis grave y el shock séptico en España disminuyó entre las 2 cohortes de pacientes de 2005 y 2011, atribuible a la precocidad y las mejoras en la atención de la sepsis
Assuntos
Humanos , Sepse/mortalidade , Choque Séptico/mortalidade , Unidades de Terapia Intensiva/estatística & dados numéricos , Avaliação de Processos e Resultados em Cuidados de Saúde , Mortalidade/tendências , Cuidados Críticos/estatística & dados numéricos , Estudos de CoortesRESUMO
OBJECTIVE: To analyze the evolution of sepsis-related mortality in Spanish Intensive Care Units (ICUs) following introduction of the Surviving Sepsis Campaign (SSC) guidelines and the relationship with sepsis process-of-care. DESIGN: A prospective cohort study was carried out, with the inclusion of all consecutive patients presenting severe sepsis or septic shock admitted to 41 Spanish ICUs during two time periods: 2005 (Edusepsis study pre-intervention group) and 2011 (ABISS-Edusepsis study pre-intervention group). SCOPE: Patients with severe sepsis or septic shock admitted to Spanish ICUs. PATIENTS: All ICU admissions from the emergency department or wards and all ICU patients with a diagnosis of severe sepsis or septic shock. A total of 1348 patients were included: 630 in the 2005 group and 718 in the 2011 group. INTERVENTION: None. PRIMARY ENDPOINTS: ICU mortality, 28-day mortality and Hospital mortality, hospital length of stay, ICU length of stay and compliance with the resuscitation bundle. RESULTS: Compliance with the resuscitation bundle was significantly greater in the 2011 group (5.7% vs. 9.9%; p=0.005), and was associated to lower mortality (OR 0.602 [0.365-0.994]; p=0.048). The 2011 group had lower absolute in-hospital mortality (44.0% vs. 32.6%; p=0.01), 28-day mortality (36.5% vs. 23.0%; p=0.01), and adjusted mortality (OR 0.64 [0.49-0.83], p=0.001). CONCLUSIONS: Mortality related to severe sepsis or septic shock in Spain decreased between two patient cohorts in 2005 and 2011, and was attributable to earliness and improvement in sepsis care.
Assuntos
Mortalidade Hospitalar/tendências , Unidades de Terapia Intensiva/estatística & dados numéricos , Pacotes de Assistência ao Paciente , Sepse/mortalidade , APACHE , Idoso , Idoso de 80 Anos ou mais , Feminino , Fidelidade a Diretrizes , Promoção da Saúde , Hospitais Universitários/estatística & dados numéricos , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Guias de Prática Clínica como Assunto , Avaliação de Programas e Projetos de Saúde , Estudos Prospectivos , Sepse/complicações , Choque Séptico/complicações , Choque Séptico/mortalidade , Espanha/epidemiologia , Centros de Atenção Terciária/estatística & dados numéricosRESUMO
High-dose chemotherapy (HDC) was investigated in high-risk neuroblastoma (HR-NBL) to reduce the risk of relapse. We report the results of the 30-year experience of a cohort of patients with HR-NBL treated with high-dose (HD) busulfan (Bu)-containing regimens. From 1980 to 2009, 215 patients aged >1 year with stage 4 NBL were treated with HD Bu-containing regimens at Gustave Roussy. These data were prospectively recorded in the Pediatric Transplantation Database. The median age at diagnosis was 40 months (12-218 months). All patients had a stage 4 neuroblastoma. NMYC amplification was displayed in 24% of the tumors. The hematopoietic support consisted of bone marrow or PBSCs in 46% and 49% of patients, respectively. The 5-year event-free survival and overall survival rates of the whole cohort were 35.1% and 40%, respectively. Age at diagnosis, bone marrow involvement and tumor response after induction chemotherapy were significant prognostic factors. Toxicity was manageable and decreased over time, owing to both PBSC administration and better supportive care. Based on this experience, HD Bu-melphalan (Mel) has been implemented in Europe and compared with Carboplatin-Etoposide-Mel in the European SIOP Neuroblastoma (SIOPEN)/HR-NBL randomized protocol. It has now become the standard HDC in the SIOPEN HR strategy.
Assuntos
Bussulfano/administração & dosagem , Melfalan/administração & dosagem , Neuroblastoma/terapia , Adolescente , Transplante de Medula Óssea/métodos , Bussulfano/toxicidade , Criança , Pré-Escolar , Estudos de Coortes , Terapia Combinada , Feminino , Humanos , Lactente , Masculino , Melfalan/toxicidade , Neuroblastoma/complicações , Neuroblastoma/mortalidade , Transplante de Células-Tronco de Sangue Periférico/métodos , Transplante de Células-Tronco de Sangue Periférico/mortalidade , Estudos Retrospectivos , Fatores de Risco , Análise de SobrevidaRESUMO
High-risk neuroblastoma is characterised by poor long-term survival, especially for very high-risk (VHR) patients (poor response of metastases after induction therapy). We report the results of an intensified high-dose chemotherapy (HDC) strategy to improve the prognosis of VHR patients. This strategy was based on tandem HDC with thiotepa and busulfan-melphalan (Bu-Mel) followed by autologous stem cell transplantation (ASCT). All data were prospectively recorded in the Gustave Roussy Paediatric ASCT database. From April 2004 to August 2011, 26 patients were eligible for tandem HDC. The median age at diagnosis was 4.4 years (1-15.9). All patients had metastatic disease. MYCN was amplified in 5/26 tumours. Despite the cumulative toxicity of alkylating agents, the toxicity of the intensified HDC strategy was manageable. Thiotepa-related toxicity was mainly digestive, whereas sinusoidal obstruction syndrome was the main toxicity observed after Bu-Mel. The 3-year event-free survival of this cohort was 37.3% (21.3-56.7). This strategy will be compared with combined (131)I-mIBG/Bu-Mel in the upcoming SIOPEN VHR Neuroblastoma Protocol.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neuroblastoma , Transplante de Células-Tronco , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Autoenxertos , Bussulfano/administração & dosagem , Bussulfano/efeitos adversos , Criança , Pré-Escolar , Intervalo Livre de Doença , Feminino , Humanos , Lactente , Masculino , Melfalan/administração & dosagem , Melfalan/efeitos adversos , Neuroblastoma/mortalidade , Neuroblastoma/terapia , Estudos Retrospectivos , Taxa de Sobrevida , Tiotepa/administração & dosagem , Tiotepa/efeitos adversosRESUMO
The prognosis of primary disseminated multifocal metastatic Ewing's sarcoma (PDMES) is poor even if a slight improvement has been achieved with high-dose alkylating agent-containing chemotherapy. To enhance treatment efficacy, we assessed the feasibility, safety and efficacy of a tandem high-dose chemotherapy (HDC) regimen. In a single institution, patients with PDMES received six courses of vincristine/ifosfamide/doxorubicin/etoposide induction therapy, followed by high-dose thiotepa, and then melphalan-busulfan, 8 weeks apart. Surgical resection of primary tumour was carried out between the two HDC regimens and 70 days after the last HDC regimen for post-operative radiotherapy or irradiation alone. From October 2002 to 2009, 13 of the 18 consecutive patients with PDMES (72%) received the full treatment programme. The other five patients experienced early progression and died. Among the 13 patients, 11 relapsed after the end of the treatment programme within 6 months (2.2-11.9) from end of therapy. Only two patients are still alive in first complete remission after 9 years. The 3-year event-free survival (EFS) and overall survival (OS) rates were 11 and 22%, respectively. The median EFS and OS duration from the diagnosis were 13.4 and 17.3 months, respectively. Neither major complications nor treatment-related death occurred. The tandem-HDC regimen was feasible, with expected side effects, but it did not improve the outcome of patients with PDMES.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Quimiorradioterapia/métodos , Sarcoma de Ewing/mortalidade , Sarcoma de Ewing/terapia , Adolescente , Adulto , Criança , Pré-Escolar , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Seguimentos , Humanos , Ifosfamida/administração & dosagem , Masculino , Taxa de Sobrevida , Tiotepa/administração & dosagem , Vincristina/administração & dosagem , Adulto JovemRESUMO
Dynamic Saccharomyces cerevisiae responses to increasing ethanol stresses were investigated to monitor yeast viability and to optimize bioprocess performance when gradients occurred due to the specific configuration of multi-stage bioreactors with cell recycling or of large volume industrial bioreactors inducing chemical heterogeneities. Twelve fed-batch cultures were carried out with initial ethanol concentrations (P(in)) ranging from 5 g l(-1) to 110 g l(-1) with three different inoculums in different physiological states in terms of viability and quantity of ethanol produced (P(o)). For a given initial cell viability of 50%, the time to reach the maximum growth rate and maximum ethanol production rate was dependent on the difference P(in) - P(o). Whatever the initial physiological state, when the initial ethanol concentration P(in) reached 100 g l(-1), the yeasts died. Experimental results showed that the initial physiological state of the yeast was the major parameter to determine, the microorganisms' capacities to adapt and resist environmental changes.
Assuntos
Reatores Biológicos/microbiologia , Etanol/metabolismo , Etanol/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/fisiologia , Engenharia Biomédica , Fermentação , Cinética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Estresse FisiológicoRESUMO
Spiramycin production by Streptomyces ambofaciens Sp181110 with glucose as the carbon source was studied under a controlled nutritional environment. In a batch culture, the glucose excess after ammonium depletion led to pyruvate and alpha-ketoglutarate accumulation. 85 mg/l of spiramycin were produced in less than 70 h during the stationary and maintenance phase on these acids after glucose exhaustion. Fed-batch strategy was designed to study spiramycin production without by-product formation and glucose accumulation. In these conditions, up to 150 mg/l were produced in less than 80 h during the stationary phase on glucose. The antibiotic titre was found independent of the glucose feeding under carbon limitation and the importance of putative intracellular reserves formed after nutrient exhaustion was suggested. Besides, spiramycin production was not inhibited by the limiting flux of glucose.
Assuntos
Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Glucose/metabolismo , Modelos Biológicos , Espiramicina/biossíntese , Streptomyces/crescimento & desenvolvimento , Streptomyces/metabolismo , Biomassa , Proliferação de Células , Simulação por Computador , Especificidade da Espécie , Streptomyces/classificaçãoRESUMO
The impact of ethanol and temperature on the dynamic behaviour of Saccharomyces cerevisiae in ethanol biofuel production was studied using an isothermal fed-batch process at five different temperatures. Fermentation parameters and kinetics were quantified. The best performances were found at 30 and 33 degrees C around 120 g l(-1) ethanol produced in 30 h with a slight benefit for growth at 30 degrees C and for ethanol production at 33 degrees C. Glycerol formation, enhanced with increasing temperatures, was coupled with growth for all fermentations; whereas, a decoupling phenomenon occurred at 36 and 39 degrees C pointing out a possible role of glycerol in yeast thermal protection.
Assuntos
Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Etanol/metabolismo , Glicerol/metabolismo , Saccharomyces cerevisiae/fisiologia , Temperatura , Proliferação de Células , Sobrevivência Celular/fisiologia , CinéticaRESUMO
In order to identify an optimal aeration strategy for intensifying bio-fuel ethanol production in fermentation processes where growth and production have to be managed simultaneously, we quantified the effect of aeration conditions--oxygen limited vs non limited culture (micro-aerobic vs aerobic culture)--on the dynamic behaviour of Saccharomyces cerevisiae cultivated in very high ethanol performance fed-batch cultures. Fermentation parameters and kinetics were established within a range of ethanol concentrations (up to 147 g l(-1)), which very few studies have addressed. Higher ethanol titres (147 vs 131 g l(-1) in 45 h) and average productivity (3.3 vs 2.6 g l(-1) h(-1)) were obtained in cultures without oxygen limitation. Compared to micro-aerobic culture, full aeration led to a 23% increase in the viable cell mass as a result of the concomitant increase in growth rate and yield, with lower ethanol inhibition. The second beneficial effect of aeration was better management of by-product production, with production of glycerol, the main by-product, being strongly reduced from 12 to 4 g l(-1). We demonstrate that aeration strategy is as much a determining factor as vitamin feeding (Alfenore et al. 2002) in very high ethanol performance (147 g l(-1) in 45 h) in order to achieve a highly competitive dynamic process.
Assuntos
Etanol/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Aerobiose , Ar , Biomassa , Reatores Biológicos , Meios de Cultura , Etanol/análise , Fermentação , Glucose/metabolismo , Glicerol/metabolismo , Microbiologia Industrial/métodos , Cinética , Consumo de Oxigênio , Fatores de Tempo , Vitaminas/farmacologiaRESUMO
Results of ready biodegradability tests (RBT) are barely reproducible owing to a well-known lack of definition in inoculum source and quality. In this study, the degree of variability expected when only activated sludges are used as inoculum source was investigated. For this, the characteristics of activated sludges collected in municipal wastewater treatment plants operating at various massic loading rates (MLR; 0.1, 0.5 and 0.9 kgBOD5 kgVSS(-1) d(-1)) were compared. In order to provide suitable cellular densities for RBT, inocula were obtained after settling of activated sludges and analyzed in terms of active and cultivable cell densities, dehydrogenasic activity, BOD5 and a general profile of hydrolytic enzymes. In our analysis, biomass obtained from the High-MLR treatment plant constituted the inoculum having the highest biodegradation potential both with respect to microbial densities and to enzyme activities. This biomass also yielded the fastest biodegradation kinetics in dodecyl benzene sulfonate RBT. An attempt of biomass homogenization of inocula on the basis of cultivable cell density and dehydrogenasic activity gave negative results with this chemical compound. Since, in practice, restriction of activated sludge sources may be difficult, our results emphasize the importance of further studies aimed at homogenization of inoculum quality and quantity.
Assuntos
Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Compostos Orgânicos/metabolismo , Oxigênio/metabolismo , Controle de Qualidade , Valores de Referência , Reprodutibilidade dos TestesRESUMO
Several bottlenecks in the alcoholic fermentation process must be overcome to reach a very high and competitive performance of bioethanol production by the yeast Saccharomyces cerevisiae. In this paper, a nutritional strategy is described that allowed S. cerevisiae to produce a final ethanol titre of 19% (v/v) ethanol in 45 h in a fed-batch culture at 30 degrees C. This performance was achieved by implementing exponential feeding of vitamins throughout the fermentation process. In comparison to an initial addition of a vitamin cocktail, an increase in the amount of vitamins and an exponential vitamin feeding strategy improved the final ethanol titre from 126 g l(-1) to 135 g l(-1) and 147 g l(-1), respectively. A maximum instantaneous productivity of 9.5 g l(-1) h(-1) was reached in the best fermentation. These performances resulted from improvements in growth, the specific ethanol production rate, and the concentration of viable cells in response to the nutritional strategy.
Assuntos
Etanol/metabolismo , Glucose/metabolismo , Saccharomyces cerevisiae/metabolismo , Vitaminas/farmacologia , Biomassa , Meios de Cultura/metabolismo , Fermentação , Microbiologia Industrial/métodos , Cinética , Saccharomyces cerevisiae/efeitos dos fármacos , Coloração e RotulagemRESUMO
With new EC regulations, alternative treatment and disposal techniques of the excess sludge produced by activated sludge wastewater treatment plants have to be developed. To decrease activated sludge production yield, microbial cell lysis can be amplified to enhance cryptic growth (biomass growth on lysates). Cell breakage techniques (thermal, alkaline and a combination) were studied to generate Ralstonia eutropha (strain model) and waste activated sludge lysates and to evaluate their biodegradability. Gentle treatment conditions by alkaline waste treatment (20 min at 60 degrees C and pH 10 by NaOH addition) allowed waste activated sludge to be solubilized by a two step process (instantaneous and post-treatment) giving a dissolved organic carbon released by the total suspended solids treated of 267 mgDOC x g(-1)TSS. The biodegradation of the soluble fraction of the lysates by fresh sludge reached 75 and 90% after 48 and 350 hrs of incubation respectively. A validation on a laboratory scale by insertion of a liquor alkaline heat treatment loop in a biological synthetic wastewater treatment process was carried out. A reduction of 37% of the excess sludge was obtained without altering the purification yield of the process.
Assuntos
Cupriavidus necator/fisiologia , Esgotos , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Biomassa , Temperatura Alta , Concentração de Íons de Hidrogênio , Dinâmica Populacional , SolubilidadeRESUMO
In submerged cultures performed in synthetic medium containing glucose and glutamate, the filamentous fungus Monascus ruber produced a red pigment and a mycotoxin, citrinin. In oxygen-limiting conditions, the production of these two metabolites was growth-associated, as was the production of primary metabolites. In oxygen-excess conditions, the profile of citrinin production was typical of a secondary metabolite, since it was produced mostly during the stationary phase. In contrast, the production of the pigment decreased rapidly throughout the culture, showing a profile characteristic of an inhibitory mechanism. The organic acids produced during the culture, L-malate and succinate, were shown to be slightly inhibitory against pigment production, while citrinin production was unaffected. However, this inhibition could not account for the observed profile of pigment production in batch cultures. Other dicarboxylic acids such as fumarate or tartrate showed a similar effect to that provoked by malate and succinate as regards pigment production. It was concluded that the decrease in red pigment production during the culture was due to the inhibitory effect of an unknown product whose accumulation was favored in aerobic conditions.
RESUMO
Strains of Saccharomyces cerevisiae deleted for TPS1 encoding trehalose-6-phosphate synthase still accumulate trehalose when harbouring a functional MAL locus. We demonstrate that this accumulation results from an active uptake of trehalose present in the 'yeast extract' used to make the enriched culture media and that no accumulation is observed in mineral media. The uptake of trehalose was shown to be mediated by the alpha-glucoside transporter encoded by AGT1, the expression of which is linked to the presence of a functional MAL locus. Deletion of this gene in a MAL+ tps1 mutant abolished trehalose accumulation on a maltose or galactose mineral medium. However, small amounts of disaccharide were still detected in a agt1 tps1 double mutant when the medium was supplemented with 10 g trehalose l(-1), indicating the existence of a non-concentrative low-affinity sugar transporter. The presence of the high-affinity trehalose permease allowed us to investigate the effect of increasing exogenous trehalose from 0 to 10 g(-1) on intracellular accumulation. A maximum of ca. 10% (wt/wt dry cells) trehalose was attained in the presence of only 1 g l(-1) of disaccharide in the medium. The capability to monitor the intracellular content of trehalose by varying its extracellular concentration, independent of genetic alterations of the trehalose metabolic machinery, allowed the remarkable contribution of this molecule in stress tolerance to be demonstrated, as the higher the trehalose content, the longer the cell survival to a severe heat shock and to glucose starvation.
Assuntos
Proteínas de Transporte de Monossacarídeos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Simportadores , Trealose/metabolismo , Transporte Biológico , Proteínas de Transporte/fisiologia , Meios de Cultura , Fermentação , Proteínas Fúngicas/fisiologia , Temperatura Alta , Maltose/metabolismoRESUMO
During submerged culture in the presence of glucose and glutamate, the filamentous fungus Monascus ruber produces water-soluble red pigments together with citrinin, a mycotoxin with nephrotoxic and hepatoxic effects on animals. Analysis of the (13)C-pigment molecules from mycelia cultivated with [1-(13)C]-, [2-(13)C]-, or [1, 2-(13)C]acetate by (13)C nuclear magnetic resonance indicated that the biosynthesis of the red pigments used both the polyketide pathway, to generate the chromophore structure, and the fatty acid synthesis pathway, to produce a medium-chain fatty acid (octanoic acid) which was then bound to the chromophore by a trans-esterification reaction. Hence, to enhance pigment production, we tried to short-circuit the de novo synthesis of medium-chain fatty acids by adding them to the culture broth. Of fatty acids with carbon chains ranging from 6 to 18 carbon atoms, only octanoic acid showed a 30 to 50% stimulation of red pigment production, by a mechanism which, in contrast to expectation, did not involve its direct trans-esterification on the chromophore backbone. However, the medium- and long-chain fatty acids tested were readily assimilated by the fungus, and in the case of fatty acids ranging from 8 to 12 carbon atoms, 30 to 40% of their initial amount transiently accumulated in the growth medium in the form of the corresponding methylketone 1 carbon unit shorter. Very interestingly, these fatty acids or their corresponding methylketones caused a strong reduction in, or even a complete inhibition of, citrinin production by M. ruber when they were added to the medium. Several data indicated that this effect could be due to the degradation of the newly synthesized citrinin (or an intermediate in the citrinin pathway) by hydrogen peroxide resulting from peroxisome proliferation induced by medium-chain fatty acids or methylketones.
Assuntos
Ascomicetos/metabolismo , Citrinina/biossíntese , Ácidos Graxos/metabolismo , Glutaratos/metabolismo , Indóis/metabolismo , Pigmentos Biológicos/biossíntese , Acetatos/metabolismo , Caprilatos/metabolismo , Isótopos de Carbono , Glucose/metabolismo , Ácido Glutâmico/metabolismo , Cetonas/metabolismo , Peroxissomos/metabolismoRESUMO
The growth and metabolic behaviour of the filamentous fungus Monascus ruber were studied in submerged cultures under various aeration and agitation conditions. Improving the oxygen supply, by increasing either the air input or the agitation speed, resulted in modified metabolism: the biomass yield, the consumption of the nitrogen source (monosodium glutamate), and the production of secondary metabolites (red pigment and citrinin) all increased. However, the citrinin production increased more than that of the red pigment. In consequence, a low oxygen transfer coefficient was required to improve the red pigment/citrinin production ratio. Copyright 1999 John Wiley & Sons, Inc.
RESUMO
To decrease activated sludge production, microbial cell lysis can be amplified to enhance cryptic growth (biomass growth on lysates). Cell breakage techniques (thermal, alkaline, acid) were studied to generate Alcaligenes eutrophus and sludge lysates and to evaluate their biodegradability. Gentle treatment conditions produced the best results. Complete cell deactivation was obtained for temperatures higher than 55 degrees C. The release kinetics were similar for temperatures varying from 60 degrees C to 100 degrees C. A 20-min incubation was suitable for reaching 80% of the maximum releasable carbon. In thermal-chemical hydrolysis, NaOH was the most efficient for inducing cell lysis. Carbon release was a two-step process. First an immediate release occurred, which was of the same order of magnitude for A. eutrophus and sludge [100-200 mg dissolved organic C (DOC) g total suspended solids (TSS)-1], followed by a post-treatment release. The second step was virtually equivalent to the first for sludge, and weaker for A. eutrophus (< 50 mg DOC g TSS-1). The biodegradability of the soluble fraction, both the immediate and the post-treatment carbon release, was investigated. The optimal degradation yield, obtained with sludge cells, reached 55% after 48 h of incubation and 80% after 350 h. The most consistent lysis and biodegradation results occurred at pH 10 and 60 degrees C after a 20-min incubation.
Assuntos
Alcaligenes/crescimento & desenvolvimento , Alcaligenes/metabolismo , Biomassa , Esgotos/microbiologia , Alcaligenes/efeitos dos fármacos , Biodegradação Ambiental , Carbono/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Hidróxido de Sódio/farmacologia , Sonicação , Temperatura , Eliminação de Resíduos LíquidosRESUMO
The trehalose content in Saccharomyces cerevisiae can be significantly manipulated by including trehalose at an appropriate level in the growth medium. Its uptake is largely dependent on the expression of AGT1, which encodes an alpha-glucoside transporter. The trehalose found in a tps1 mutant of trehalose synthase may therefore largely reflect its uptake from the enriched medium that was employed.
Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas de Transporte de Monossacarídeos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Simportadores , Trealose/metabolismo , Transporte Biológico , Galactose/metabolismo , Glucose/metabolismo , Glucosiltransferases/genética , Cinética , Saccharomyces cerevisiae/crescimento & desenvolvimentoRESUMO
Carbon isotope distribution of [13C]citrinin from Monascus ruber incubated with [13C]acetate revealed that the biosynthesis of the toxin originated from a tetraketide, instead of a pentaketide as has been shown for Penicillium and Aspergillus species. The production of polyketide red pigments and citrinin by M. ruber may therefore be regulated at the level of the tetraketide branch point.
RESUMO
Among the numerous yeasts able to produce flavor compounds, several strains of Kluyveromyces species are known for the synthesis of large amounts of aromatic compounds. In particular, the accumulation of 2-phenylethyl alcohol in liquid cultures of Kluyveromyces marxianus was observed after incubation on a semisynthetic medium at 30 degrees C, 125 rpm. Changes in the carbon sources led to a significant modification of the amount of this aromatic compound; moreover, the variations in the level of DL-phenylalanine and the exclusive use of a precursor isomer (L) also affected the synthesis of 2-phenylethyl alcohol. Finally, this study revealed the growth inhibition of K. marxianus when the concentration of 2-phenylethyl alcohol reached a critical value near 1.4 g/L; the use of an exponential model allowed the inhibition constant ki to be determined (ki = 0.35 g/L).