RESUMEN
The effects of respiratory inhibitors, quinone analogues and artificial substrates on the membrane-bound electron transport system of the fastidious ß-proteobacterium Eikenella corrodens grown under O2-limited conditions were studied. NADH respiration in isolated membrane particles were partially inhibited by rotenone, dicoumarol, quinacrine, flavone, and capsaicin. A similar response was obtained when succinate oxidation was performed in the presence of thenoyltrifluoroacetone and N,N'-dicyclohexylcarbodiimide. NADH respiration was resistant to site II inhibitors and cyanide, indicating that a percentage of the electrons transported can reach O2 without the bc1 complex. Succinate respiration was sensitive to myxothiazol, antimycin A and 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Juglone, plumbagin and menadione had higher reactivity with NADH dehydrogenase. The membrane particles showed the highest oxidase activities with ascorbate-TCHQ (tetrachlorohydroquinone), TCHQ alone, and NADH-TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine), and minor activity levels with ascorbate-DCPIP (2,6-dichloro-phenolindophenol) and NADH-DCPIP. The substrates NADH-DCPIP, NADH-TMPD and TCHQ were electron donors to cyanide-sensitive cbb' cytochrome c oxidase. The presence of dissimilatory nitrate reductase in the aerobic respiratory system of E. corrodens ATCC 23834 was demonstrated by first time. Our results indicate that complexes I and II have resistance to their classic inhibitors, that the oxidation of NADH is stimulated by juglone, plumbagin and menadione, and that sensitivity to KCN is stimulated by the substrates TCHQ, NADH-DCPIP and NADH-TMPD.
Asunto(s)
Proteínas Bacterianas , Eikenella corrodens/enzimología , Complejo I de Transporte de Electrón , Consumo de Oxígeno/efectos de los fármacos , Quinonas , Desacopladores , Aerobiosis/efectos de los fármacos , Proteínas Bacterianas/antagonistas & inhibidores , Proteínas Bacterianas/metabolismo , Transporte de Electrón/efectos de los fármacos , Complejo I de Transporte de Electrón/antagonistas & inhibidores , Complejo I de Transporte de Electrón/metabolismo , NAD/metabolismo , Quinonas/química , Quinonas/farmacología , Desacopladores/química , Desacopladores/farmacologíaRESUMEN
Beta-alanine supplementation (BA) has a positive impact on physical performance. However, evidence showing a benefit of this amino acid in aerobic-anaerobic transition zones is scarce and the results controversial. The aim of this systematic review and meta-analysis is to analyze the effects of BA supplementation on physical performance in aerobic-anaerobic transition zones. At the same time, the effect of different dosages and durations of BA supplementation were identified. The search was designed in accordance with the PRISMA® guidelines for systematic reviews and meta-analyses and performed in Web of Science (WOS), Scopus, SPORTDiscus, PubMed, and MEDLINE between 2010 and 2020. The methodological quality and risk of bias were evaluated with the Cochrane Collaboration tool. The main variables were the Time Trial Test (TTT) and Time to Exhaustion (TTE) tests, the latter separated into the Limited Time Test (LTT) and Limited Distance Test (LDT). The analysis was carried out with a pooled standardized mean difference (SMD) through Hedges' g test (95% CI). Nineteen studies were included in the systematic review and meta-analysis, revealing a small effect for time in the TTT (SMD, -0.36; 95% CI, -0.87-0.16; I2 = 59%; p = 0.010), a small effect for LTT (SMD, 0.25; 95% CI, -0.01-0.51; I2 = 0%; p = 0.53), and a large effect for LDT (SMD, 4.27; 95% CI, -0.25-8.79; I2 = 94%; p = 0.00001). BA supplementation showed small effects on physical performance in aerobic-anaerobic transition zones. Evidence on acute supplementation is scarce (one study); therefore, exploration of acute supplementation with different dosages and formats on physical performance in aerobic-anaerobic transition zones is needed.
Asunto(s)
Aerobiosis/fisiología , Anaerobiosis/fisiología , Suplementos Dietéticos , Rendimiento Físico Funcional , Fenómenos Fisiológicos en la Nutrición Deportiva/fisiología , beta-Alanina/administración & dosificación , Aerobiosis/efectos de los fármacos , Anaerobiosis/efectos de los fármacos , Humanos , beta-Alanina/farmacologíaRESUMEN
PURPOSE: Nicotinamide riboside (NR) acts as a potent NAD+ precursor and improves mitochondrial oxidative capacity and mitochondrial biogenesis in several organisms. However, the effects of NR supplementation on aerobic performance remain unclear. Here, we evaluated the effects of NR supplementation on the muscle metabolism and aerobic capacity of sedentary and trained mice. METHODS: Male C57BL/6 J mice were supplemented with NR (400 mg/Kg/day) over 5 and 10 weeks. The training protocol consisted of 5 weeks of treadmill aerobic exercise, for 60 min a day, 5 days a week. Bioinformatic and physiological assays were combined with biochemical and molecular assays to evaluate the experimental groups. RESULTS: NR supplementation by itself did not change the aerobic performance, even though 5 weeks of NR supplementation increased NAD+ levels in the skeletal muscle. However, combining NR supplementation and aerobic training increased the aerobic performance compared to the trained group. This was accompanied by an increased protein content of NMNAT3, the rate-limiting enzyme for NAD + biosynthesis and mitochondrial proteins, including MTCO1 and ATP5a. Interestingly, the transcriptomic analysis using a large panel of isogenic strains of BXD mice confirmed that the Nmnat3 gene in the skeletal muscle is correlated with several mitochondrial markers and with different phenotypes related to physical exercise. Finally, NR supplementation during aerobic training markedly increased the amount of type I fibers in the skeletal muscle. CONCLUSION: Taken together, our results indicate that NR may be an interesting strategy to improve mitochondrial metabolism and aerobic capacity.
Asunto(s)
Aerobiosis/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , NAD/metabolismo , Niacinamida/análogos & derivados , Compuestos de Piridinio/metabolismo , Compuestos de Piridinio/farmacología , Animales , Respiración de la Célula/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Niacinamida/metabolismo , Niacinamida/farmacologíaRESUMEN
The aim of this study was to applythe Health Belief Model to explain the adherence to the recommendation not to recap needles by dentists and dental assistants of the public health system in a municipality in the State of São Paulo. A questionnaire validated and adapted for the oral health area was used, which included variables related to the frequency of recapping and health beliefs using Likert-type scales. The relationship between beliefs and adherence to the recommendation not to recap needles was obtained by regression analysis. Of all the professionals in this study (n=79), the majority (83.5%) reported recapping needles at least once in the last month. Through regression analysis, it was observed that the relationship between the beliefs described by the model and the attitude whether or not to follow the recommendation not to recap needles was explained by a lower perception of psychological barriers and a greater perception of stimuli not to recap needles. The conclusion reached is that the acceptance of recommendations to prevent working accidents with biological material was explained by some dimensions of the Health Belief Model, enabling discussion about reformulation of training offered to professionals of the public health system.
Objetivou-se neste estudo aplicar o Modelo de Crenças em Saúde a fim de explicar a adesão à recomendação de não reencapar agulhas por cirurgiões-dentistas e auxiliares de saúde bucal da rede pública de um município paulista. Utilizou-se um questionário validado e adaptado para a área de saúde bucal, que contemplava variáveis relativas à frequência do reencape e crenças em saúde, por meio de escalas tipo Likert. A relação entre as crenças e a adesão à recomendação de não reencapar agulhas foi obtida por meio da análise de regressão. Da amostra de profissionais obtida por adesão ao estudo (n = 79), a maioria (83,5%) relatou ter reencapado agulhas pelo menos alguma vez no último mês. Por meio da análise de regressão, foi observado que a relação entre as crenças descritas pelo modelo e a atitude de aderir ou não à recomendação de não reencapar agulhas foi explicada por uma menor percepção de barreiras psicológicas e por uma maior percepção de estímulos para não reencapar agulhas. Conclui-se que a aceitação das recomendações para prevenir acidentes do trabalho com material biológico foi explicado por algumas dimensões do Modelo de Crenças em Saúde, possibilitando a discussão sobre a reformulação de capacitações oferecidas para profissionais do sistema público de saúde.
Asunto(s)
Animales , Bovinos , Complejo I de Transporte de Electrón/metabolismo , Células Endoteliales/enzimología , Hiperoxia/metabolismo , Mitocondrias/enzimología , Arteria Pulmonar/citología , Arteria Pulmonar/enzimología , Ubiquinona/metabolismo , Aerobiosis/efectos de los fármacos , Benzoquinonas/farmacología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cromatografía Líquida de Alta Presión , Medios de Cultivo , Complejo I de Transporte de Electrón/antagonistas & inhibidores , Células Endoteliales/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Ferricianuros/farmacología , L-Lactato Deshidrogenasa/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Oxidación-Reducción/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Arteria Pulmonar/efectos de los fármacos , Espectrofotometría , Cloruro de Tolonio/farmacología , Ubiquinona/análisis , Ubiquinona/farmacologíaRESUMEN
Escherichia coli exposed to tellurite shows augmented membrane lipid peroxidation and ROS content. Also, reduced thiols, protein carbonylation, [Fe-S] center dismantling, and accumulation of key metabolites occur in these bacteria. In spite of this, not much is known about tellurite effects on the E. coli electron transport chain (ETC). In this work, tellurite-mediated damage to the E. coli ETC's NADH dehydrogenases and terminal oxidases was assessed. Mutant lacking ETC components showed delayed growth, decreased oxygen consumption and increased ROS in the presence of the toxicant. Membranes from tellurite-exposed E. coli exhibited decreased oxygen consumption and dNADH/NADH dehydrogenase activity, showing an impairment of NDH-I but not of NDH-II activity. Regarding terminal oxidases, only the bo oxidase complex was affected by tellurite. When assaying NDH-I and NDH-II activity in the presence of superoxide, the NDH-I complex was preferentially damaged. The activity was partly restored in the presence of reducing agents, sulfide and Fe(2+) under anaerobic conditions, suggesting that damage affects NDH-I [4Fe-4S] centers. Finally, augmented membrane protein oxidation along with reduced oxidase activity was observed in the presence of the toxicant. Also, the increased expression of genes encoding alternative terminal oxidases probably reflects a cell's change towards anaerobic respiration when facing tellurite.
Asunto(s)
Proteínas de Escherichia coli/metabolismo , Escherichia coli/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica , NADH Deshidrogenasa/metabolismo , Oxidorreductasas/metabolismo , Telurio/toxicidad , Aerobiosis/efectos de los fármacos , Anaerobiosis/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Membrana Celular/enzimología , Membrana Celular/genética , Escherichia coli/enzimología , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Isoenzimas/genética , Isoenzimas/metabolismo , NADH Deshidrogenasa/genética , Oxidación-Reducción/efectos de los fármacos , Oxidorreductasas/genética , Consumo de Oxígeno/efectos de los fármacos , Carbonilación Proteica/efectos de los fármacos , Superóxidos/metabolismoRESUMEN
Crude glycerol, also known as glycerin, is the main byproduct of the biodiesel industry. It has been estimated that up to 40,000 tons of glycerin will be produced each year by 2020. This study evaluated the value-added use of crude glycerol derived from soybean biodiesel preparation as a carbon source for heterologous protein production using the yeast Pichia pastoris. Eleven glycerin samples were obtained by methanolysis of soybean oil using different acids or bases as catalysts. Cell growth experiments showed that crude glycerol containing either potassium or sodium hydroxide resulted in 1.5-2 times higher final cell densities when compared to glycerol P.A. Finally, crude glycerol containing sodium hydroxide was successfully utilized for constitutive heterologous α-amylase production in P. pastoris. This study demonstrated that crude glycerol without any purification steps may be directly used as carbon source for protein production in P. pastoris.
Asunto(s)
Biocombustibles , Carbono/farmacología , Glicerol/farmacología , Pichia/metabolismo , Aceite de Soja/química , alfa-Amilasas/biosíntesis , Aerobiosis/efectos de los fármacos , Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/enzimología , Catálisis/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Fermentación/efectos de los fármacos , Metanol/farmacología , Pichia/efectos de los fármacos , Pichia/crecimiento & desarrolloRESUMEN
Age-related diseases are associated with increased production of reactive oxygen and carbonyl species such as methylglyoxal. Aminoacetone, a putative threonine catabolite, is reportedly known to undergo metal-catalyzed oxidation to methylglyoxal, NH4(+) ion, and H2O2 coupled with (i) permeabilization of rat liver mitochondria, and (ii) apoptosis of insulin-producing cells. Oxidation of aminoacetone to methylglyoxal is now shown to be accelerated by ferricytochrome c, a reaction initiated by one-electron reduction of ferricytochrome c by aminoacetone without amino acid modifications. The participation of O2(â¢-) and HO (â¢) radical intermediates is demonstrated by the inhibitory effect of added superoxide dismutase and Electron Paramagnetic Resonance spin-trapping experiments with 5,5'-dimethyl-1-pyrroline-N-oxide. We hypothesize that two consecutive one-electron transfers from aminoacetone (E0 values = -0.51 and -1.0 V) to ferricytochrome c (E0 = 0.26 V) may lead to aminoacetone enoyl radical and, subsequently, imine aminoacetone, whose hydrolysis yields methylglyoxal and NH4(+) ion. In the presence of oxygen, aminoacetone enoyl and O2(â¢-) radicals propagate aminoacetone oxidation to methylglyoxal and H2O2. These data endorse the hypothesis that aminoacetone, putatively accumulated in diabetes, may directly reduce ferricyt c yielding methylglyoxal and free radicals, thereby triggering redox imbalance and adverse mitochondrial responses.
Asunto(s)
Acetona/análogos & derivados , Citocromos c/metabolismo , Carbonilación Proteica , Piruvaldehído/metabolismo , Estrés Fisiológico , Acetona/metabolismo , Aerobiosis/efectos de los fármacos , Animales , Catálisis/efectos de los fármacos , Dicroismo Circular , Simulación por Computador , Cobre/farmacología , Citocromos c/química , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres/metabolismo , Hemo/metabolismo , Caballos , Iones , Hierro/farmacología , Oxidación-Reducción/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Carbonilación Proteica/efectos de los fármacos , Ratas , Espectrofotometría Ultravioleta , Estrés Fisiológico/efectos de los fármacos , TemperaturaRESUMEN
Xylella fastidiosa is a xylem-limited bacterium responsible for important plant diseases, like citrus-variegated chlorosis (CVC) and grapevine Pierce's disease (PD). Interestingly, in vitro growth of X. fastidiosa in chemically defined media that resemble xylem fluid has been achieved, allowing studies of metabolic processes used by xylem-dwelling bacteria to thrive in such nutrient-poor conditions. Thus, we performed microarray hybridizations to compare transcriptomes of X. fastidiosa cells grown in 3G10-R, a medium that resembles grape sap, and in Periwinkle Wilt (PW), the complex medium traditionally used to cultivate X. fastidiosa. We identified 299 transcripts modulated in response to growth in these media. Some 3G10R-overexpressed genes have been shown to be upregulated in cells directly isolated from infected plants and may be involved in plant colonization, virulence and environmental competition. In contrast, cells cultivated in PW show a metabolic switch associated with increased aerobic respiration and enhanced bacterial growth rates.
Asunto(s)
Medios de Cultivo/farmacología , Perfilación de la Expresión Génica , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Xylella/crecimiento & desarrollo , Xylella/genética , Xilema/metabolismo , Xilema/microbiología , Aerobiosis/efectos de los fármacos , Aerobiosis/genética , Transporte de Electrón/efectos de los fármacos , Transporte de Electrón/genética , Genes Bacterianos/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transcripción Genética/efectos de los fármacos , Regulación hacia Arriba/efectos de los fármacos , Xylella/citología , Xylella/efectos de los fármacos , Xilema/efectos de los fármacosRESUMEN
Rice straw hemicellulosic hydrolysate was used as fermentation medium for ethanol production by Pichia stipitis NRRL Y-7124. Shaking bath experiments were initially performed aiming to establish the best initial xylose concentration to be used in this bioconversion process. In the sequence, assays were carried out under different agitation (100 to 200 rpm) and aeration (V(flask)/V(medium) ratio varying from 2.5 to 5.0) conditions, and the influence of these variables on the fermentative parameters values (ethanol yield factor, Y(P/S); cell yield factor, Y(X/S); and ethanol volumetric productivity, Q(P)) was investigated through a 2(2) full-factorial design. Initial xylose concentration of about 50 g/l was the most suitable for the development of this process, since the yeast was able to convert substrate in product with high efficiency. The factorial design assays showed a strong influence of both process variables in all the evaluated responses. The agitation and aeration increase caused a deviation in the yeast metabolism from ethanol to biomass production. The best results (Y(P/S) = 0.37 g/g and Q(P) = 0.39 g/l.h) were found when the lowest aeration (2.5 V(flask)/V(medium) ratio) and highest agitation (200 rpm) levels were employed. Under this condition, a process efficiency of 72.5% was achieved. These results demonstrated that the establishment of adequate conditions of aeration is of great relevance to improve the ethanol production from xylose by Pichia stipitis, using rice straw hemicellulosic hydrolysate as fermentation medium.