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1.
Aging Male ; 22(3): 163-168, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29336195

RESUMO

Symptomatic hydroceles are commonly treated with surgical repair. They are associated with sexual dysfunction in the aging male. Patients who are not fit for surgery often undergo aspiration and sclerotherapy of the hydrocele. There is a range of sclerosing agents used in the literature. I performed a literature search to assess whether one sclerosant was better than the others. STDS is the sclerosing agent with the best cure rate after a single injection and low side effect rates. The cure rates of sodium tetradecyl sulphate (STDS) after a single aspiration and injection were 76%. After multiple treatments 94% achieved a cure. Patient satisfaction rates at mean 40 months were 95%. Complication rates were generally low and much lower than surgical repair. Aspiration and sclerotherapy have a role in treating symptomatic hydroceles. This literature review shows that this is over and above its current use in the UK, where it is used for patients unfit for general anaesthetic. If the patients are carefully selected for this procedure, they can have a good outcome and avoid the higher complication rate and longer recovery rates of surgical repair. Patients should be counselled about aspiration and sclerotherapy as part of the informed consent process.


Assuntos
Paracentese , Escleroterapia , Hidrocele Testicular/terapia , Idoso , Prática Clínica Baseada em Evidências , Humanos , Masculino , Paracentese/efeitos adversos , Paracentese/métodos , Seleção de Pacientes , Escleroterapia/efeitos adversos , Escleroterapia/métodos
2.
Free Radic Biol Med ; 98: 2-12, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26855421

RESUMO

The field of redox biology is inherently intertwined with oxidative stress biomarkers. Oxidative stress biomarkers have been utilized for many different objectives. Our analysis indicates that oxidative stress biomarkers have several salient applications: (1) diagnosing oxidative stress, (2) pinpointing likely redox components in a physiological or pathological process and (3) estimating the severity, progression and/or regression of a disease. On the contrary, oxidative stress biomarkers do not report on redox signaling. Alternative approaches to gain more mechanistic insights are: (1) measuring molecules that are integrated in pathways linking redox biochemistry with physiology, (2) using the exomarker approach and (3) exploiting -omics techniques. More sophisticated approaches and large trials are needed to establish oxidative stress biomarkers in the clinical setting.


Assuntos
Estresse Oxidativo , Biomarcadores , Doença , Exercício Físico/fisiologia , Humanos , Oxirredução
3.
Free Radic Biol Med ; 70: 23-32, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24525000

RESUMO

Several redox-regulated responses to an acute exercise bout fail in aged animal skeletal muscle, including the ability to upregulate the expression of antioxidant defense enzymes and heat shock proteins (HSPs). These findings are generally derived from studies on sedentary rodent models and thus may be related to reduced physical activity and/or intraspecies differences as opposed to aging per se. This study, therefore, aimed to determine the influence of age and training status on the expression of HSPs, antioxidant enzymes, and NO synthase isoenzymes in quiescent and exercised human skeletal muscle. Muscle biopsy samples were obtained from the vastus lateralis before and 3 days after an acute high-intensity-interval exercise bout in young trained, young untrained, old trained, and old untrained subjects. Levels of HSP72, PRX5, and eNOS were significantly higher in quiescent muscle of older compared with younger subjects, irrespective of training status. 3-NT levels were elevated in muscles of the old untrained but not the old trained state, suggesting that lifelong training may reduce age-related macromolecule damage. SOD1, CAT, and HSP27 levels were not significantly different between groups. HSP27 content was upregulated in all groups studied postexercise. HSP72 content was upregulated to a greater extent in muscle of trained compared with untrained subjects postexercise, irrespective of age. In contrast to every other group, old untrained subjects failed to upregulate CAT postexercise. Aging was associated with a failure to upregulate SOD2 and a downregulation of PRX5 in muscle postexercise, irrespective of training status. In conclusion, lifelong training is unable to fully prevent the progression toward a more stressed muscular state as evidenced by increased HSP72, PRX5, and eNOS protein levels in quiescent muscle. Moreover, lifelong training preserves some (e.g., CAT) but not all (e.g., SOD2, HSP72, PRX5) of the adaptive redox-regulated responses after an acute exercise bout. Collectively, these data support many but not all of the findings from previous animal studies and suggest parallel aging effects in humans and mice at rest and after exercise that are not modulated by training status in human skeletal muscle.


Assuntos
Antioxidantes/metabolismo , Exercício Físico/fisiologia , Proteínas de Choque Térmico HSP27/metabolismo , Músculo Esquelético/metabolismo , Envelhecimento , Animais , Biópsia , Humanos , Camundongos , Músculo Esquelético/fisiologia , Oxirredução , Condicionamento Físico Animal
4.
J Sports Sci ; 31(4): 344-53, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23083379

RESUMO

The current study implemented a two-part design to (1) assess the vitamin D concentration of a large cohort of non-vitamin D supplemented UK-based athletes and 30 age-matched healthy non-athletes and (2) to examine the effects of 5000 IU · day(-1) vitamin D(3) supplementation for 8-weeks on musculoskeletal performance in a placebo controlled trial. Vitamin D concentration was determined as severely deficient if serum 25(OH)D < 12.5 nmol · l(-1), deficient 12.5-30 nmol · l(-1) and inadequate 30-50 nmol · l(-1). We demonstrate that 62% of the athletes (38/61) and 73% of the controls (22/30) exhibited serum total 25(OH)D < 50 nmol · l(-1). Additionally, vitamin D supplementation increased serum total 25(OH)D from baseline (mean ± SD = 29 ± 25 to 103 ± 25 nmol · l(-1), P = 0.0028), whereas the placebo showed no significant change (53 ± 29 to 74 ± 24 nmol · l(-1), P = 0.12). There was a significant increase in 10 m sprint times (P = 0.008) and vertical-jump (P = 0.008) in the vitamin D group whereas the placebo showed no change (P = 0.587 and P = 0.204 respectively). The current data supports previous findings that athletes living at Northerly latitudes (UK = 53° N) exhibit inadequate vitamin D concentrations (<50 nmol · l(-1)). Additionally the data suggests that inadequate vitamin D concentration is detrimental to musculoskeletal performance in athletes. Future studies using larger athletic groups are now warranted.


Assuntos
Desempenho Atlético/fisiologia , Suplementos Nutricionais , Músculo Esquelético/fisiologia , Estações do Ano , Esportes/fisiologia , Deficiência de Vitamina D/complicações , Vitamina D/uso terapêutico , Adolescente , Adulto , Estudos de Casos e Controles , Humanos , Masculino , Movimento/fisiologia , Esforço Físico/efeitos dos fármacos , Esforço Físico/fisiologia , Prevalência , Corrida/fisiologia , Reino Unido , Vitamina D/administração & dosagem , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/prevenção & controle , Adulto Jovem
5.
Biogerontology ; 13(6): 621-31, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23187721

RESUMO

The aim of the present study was to examine the effects of ageing and training status on (1) markers of skeletal muscle mitochondrial content and (2) the ability to activate the acute signalling pathways associated with regulating exercise-induced mitochondrial biogenesis. Muscle biopsies were obtained from the vastus lateralis muscle of young untrained (24 ± 4 years, n = 6; YU), young trained (22 ± 3 years, n = 6; YT), old untrained (65 ± 6 years, n = 6; OU) and old trained (64 ± 3 years, n = 6; OT) healthy males before and after (3 h and 3 days post-exercise) completion of high-intensity interval cycling exercise. In resting muscle, lifelong training preserved mtDNA, PGC-1α and COXIV protein content such that muscles from OT individuals were comparable to muscles from both YU and YT individuals, whereas lifelong sedentary behaviour reduced such markers of mitochondrial content. Regardless of age or training status, acute exercise induced comparable increases in p38MAPK phosphorylation immediately post-exercise, PGC-1α and COXIV mRNA expression at 3 h post-exercise and COXIV protein at 3 days post-exercise. Data demonstrate that lifelong endurance training preserves skeletal muscle PGC-1α content and that despite the mitochondrial dysfunction typically observed with sedentary ageing, muscles from sedentary elderly individuals retain the capacity to activate the acute signalling pathways associated with regulating the early processes of mitochondrial biogenesis. We consider our data to have immediate translational potential as they highlight the potential therapeutic effects of exercise to induce skeletal muscle mitochondrial biogenesis persist late in adulthood, even after a lifetime of physical inactivity.


Assuntos
Teste de Esforço/métodos , Mitocôndrias/fisiologia , Esforço Físico/fisiologia , Aptidão Física/fisiologia , Músculo Quadríceps , Comportamento Sedentário , Adulto , Fatores Etários , Idoso , Biópsia , DNA Mitocondrial/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Proteínas de Choque Térmico/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fosforilação , Músculo Quadríceps/metabolismo , Músculo Quadríceps/patologia , Transdução de Sinais , Fatores de Transcrição/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
J Sports Med Phys Fitness ; 52(1): 63-70, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22327088

RESUMO

AIM: The aim of the study was to determine the direction of change in performance variables at fixed blood lactate concentrations following vitamin E (VE) supplementation. METHODS: In a paired-matched design twelve (male: N.=8; female: N.=4) trained runners were allocated to a VE (N.=6; 268 mg·d⁻¹) or placebo (N.=6; glucose: 30 mg·d⁻¹) group for 35 days. Participants completed a discontinuous incremental exercise test, pre and post supplementation, to determine peak oxygen uptake (VO2peak) running velocity and percentage of peak oxygen uptake (%(VO2peak) at the lactate threshold (TLAC) and the onset of blood lactate accumulation (OBLA). Participants maintained a standardised training regime throughout the supplementation period. RESULTS: VE supplementation failed to significantly enhance velocity at TLAC (P=0.91) and OBLA (P=0.22) compared to a placebo treatment. Analogously, VE did not significantly enhance %(VO2peak) at TLAC (P=0.85) and OBLA (P=0.71) compared to a placebo treatment. Whilst VE supplementation did not enhance performance it did not impair performance compared to a placebo. Training significantly enhanced velocity at TLAC (P=0.00) and OBLA (P=0.05). No training-induced improvements in %VO2peak at TLAC (P=0.06) and OBLA (P=0.40) were observed. CONCLUSION: Daily VE supplementation for 35 days does not enhance or impair physiological performance at fixed blood lactate concentrations. Long-term VE supplementation for the purposes of performance enhancement is not recommended.


Assuntos
Antioxidantes/administração & dosagem , Desempenho Atlético/fisiologia , Ácido Láctico/sangue , Corrida/fisiologia , Vitamina E/administração & dosagem , Feminino , Humanos , Masculino , Consumo de Oxigênio/fisiologia , Método Simples-Cego
7.
Artigo em Inglês | MEDLINE | ID: mdl-21896942

RESUMO

Production of reactive oxygen species (ROS) during contractions is associated with muscular fatigue and damage in the short-term and adaptive responses in the long-term. When adaptation is inconsequential acute antioxidant supplementation may be able to attenuate muscle fatigue and damage to enhance performance. This study aimed to determine the effects of acute oral N-acetylcysteine (NAC) supplementation on Yo-Yo intermittent recovery test performance level one (YIRT-L1) following repeated-bouts of damaging intermittent exercise. In a pair-matched design, twelve recreationally-trained males engaged in either six days of NAC (n = 6) or placebo (n = 6) supplementation. Following a treatment loading day, participants completed three testing sessions, on alternate days, consisting of a pre-exercise Isokinetic dynamometry (IKD) test, a damaging intermittent exercise protocol, YIRT-L1 and a post-exercise IKD. A further IKD test was completed on the two intervening days. NAC treatment resulted in a significant preservation of YIRT-L1 performance (P≤0.0005). IKD performance significantly deteriorated over time at all contractions speeds and this deterioration was not influenced by treatment group. Plasma creatine kinase values increased significantly over time (P=.002) and were significantly greater in the NAC group compared with the placebo group (P=.029). NAC induced mild-gastrointenstinal side effects. NAC supplementation may be a useful strategy to enhance performance during short-term competitive situations where adaption is inconsequential. Titration studies to elucidate a treatment dose that enhances performance without inducing side-effects are now required.

8.
Plasmid ; 30(2): 90-105, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8234495

RESUMO

In some strains of cyanobacteria the composition of the light-harvesting antennae is determined by the color of available light. The mechanism of this chromatic adaptation involves the regulation of gene expression by red and green light and has been most studied in Fremyella diplosiphon (Calothrix sp. PCC 7601), a filamentous cyanobacterium for which there has been no reported means of genetic manipulation. We have constructed shuttle plasmids which can be efficiently mobilized by RP4 from Escherichia coli into F. diplosiphon and which can be recovered from transconjugant F. diplosiphon and returned to E. coli by transformation. The ability of these plasmids to replicate in F. diplosiphon is conferred by an 8.0-kb DNA fragment isolated from pFDA, a plasmid native to F. diplosiphon. To create these shuttle plasmids the 8.0-kb fragment was cloned into pJCF22, a mobilizable plasmid constructed from oriV and bom from pBR322, cat from pACYC184 and aphA from pACYC177.pJCF22 lacks sites for the restriction enzymes FdiI and II. Transconjugant F. diplosiphon containing shuttle plasmid pJCF62 are resistant to chloramphenicol and highly resistant to the aminoglycosides, G418 and neomycin. When aadA from the omega interposon was incorporated into a shuttle plasmid transconjugant F. diplosiphon could also be selected with streptomycin or spectinomycin. In F. diplosiphon shuttle plasmid pJCF62 replicates with a minimum copy number of seven. The oriV for replication in F. diplosiphon was localized to a 2.8-kb region within the cyanobacterial part of pJCF62. The presence on a shuttle plasmid of a single recognition site for FdiI reduced the efficiency of mobilization into F. diplosiphon by 5- to 10-fold. Restriction at this site was prevented when the E. coli donor strain in the mating contained the enzyme Eco47II methylase.


Assuntos
Cianobactérias/genética , Escherichia coli/genética , Vetores Genéticos , Plasmídeos , Fatores R , Conjugação Genética , Cianobactérias/crescimento & desenvolvimento , DNA Recombinante/metabolismo , Resistência Microbiana a Medicamentos/genética , Escherichia coli/crescimento & desenvolvimento , Técnicas Genéticas , Mapeamento por Restrição
9.
J Bacteriol ; 175(17): 5701-5, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8366056

RESUMO

A 2.9-kbp replication origin from a plasmid endogenous to the filamentous cyanobacterium Fremyella diplosiphon UTEX 481 was genetically characterized and sequenced. Deletion analysis of the 2.9-kbp DNA fragment delimited the minimum region necessary for replication in F. diplosiphon Fd33 to approximately 2.5 kbp. DNA sequence analysis revealed that the F. diplosiphon plasmid replication origin is structurally very similar to and shares significant identity with the 1.75-kbp replication origin reported for plasmid pDU1, isolated from the morphologically distinct cyanobacterium Nostoc sp. strain PCC 7524. Each cyanobacterial plasmid replication origin includes a large open reading frame that predicts a conserved protein of unknown function; the predicted proteins of the replication origins are of similar sizes and 30% identical in amino acid sequence. Each cyanobacterial plasmid replication origin also possesses a region of dyad symmetry approximately 300 bp upstream of the conserved open reading frame.


Assuntos
Cianobactérias/genética , Replicação do DNA/genética , DNA Bacteriano/genética , Plasmídeos , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Dados de Sequência Molecular , Fases de Leitura Aberta , Mapeamento por Restrição , Deleção de Sequência , Homologia de Sequência de Aminoácidos
12.
J Bacteriol ; 153(3): 1486-92, 1983 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-6402499

RESUMO

The chromatically adapting cyanobacterium, Fremyella diplosiphon, when grown in cool white fluorescent light, contains phycoerythrin as its predominant phycobiliprotein. When grown on agar plates with cool white illumination, mutant colonies deficient or devoid of phycoerythrin can be visibly distinguished from the wild type. A total of 25 anomalously pigmented strains were isolated and examined for their ability to chromatically adapt. Based on absorption spectra of cell extracts and on fluorescence emission spectra of intact filaments, we assigned each mutant to one of three classes. In green mutants (16 strains), the photoinduction of phycoerythrin synthesis by green light was lost or impaired, whereas the photorepression of phycocyanin synthesis by green light still functioned as in the wild type. In blue mutants (eight strains), both the ability to photoinduce phycoerythrin synthesis and the ability to photorepress phycocyanin synthesis were lost or impaired. Filaments of blue mutants exhibited a high fluorescence emission at 660 nm. A black mutant (one strain) exhibited partial induction of phycoerythrin and partial repression of phycocyanin in both red and cool white light. From the data, we suggest that in information transduction for chromatic adaptation, early events are common to both phycoerythrin and phycocyanin regulation and that blue mutants possess lesions in these early events. The lesions in green mutants occur in a subsequent branch of the information transduction pathway which is specific for phycoerythrin photoinduction.


Assuntos
Adaptação Biológica , Cianobactérias/genética , Mutação , Pigmentação , Cianobactérias/isolamento & purificação , Espectrometria de Fluorescência
13.
Biochim Biophys Acta ; 590(2): 141-58, 1980 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-6245683

RESUMO

The type and number of respiratory chain components present in membranes of Thiobacillus ferrooxidans have been investigated. These redox components were resolved potentiometrically and kinetically. Using optical techniques two cytochromes a1, multiple cytochromes c and two cytochromes b were detected. By using electron paramagnetic resonance, two copper-containing centres, high and low spin ferric haems and a ferredoxin centre were detected. Based on the combination of a potentiometric resolution and a kinetic study a model for the sequence of the respiratory chain components in the Fe2+ to O2 branch of the T. ferrooxidans respiratory chain is proposed.


Assuntos
Ferro/metabolismo , Consumo de Oxigênio , Thiobacillus/metabolismo , Citocromos/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Transporte de Elétrons , Cinética , Oxirredução , Potenciometria , Espectrofotometria
14.
Biochem J ; 156(3): 481-91, 1976 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-182152

RESUMO

1. In electron-transport particles (ET particles) prepared from Nitrobacter winogradskyi, the uncoupling agent carbonyl cyanide phenylhydrazone increased the rate of NADH oxidation but decreased the rate of oxidation of NO2-. Its effectiveness in stimulating NADH oxidation closely paralleled its effectiveness in inhibiting NO2- oxidation. 2. In the presence of ADP and phosphate the oxidation of NADH was stimulated, whereas the oxidation of NO2- was inhibited. In the presence of excess of Pi the concentration dependence with respect to ADP was the same for acceleration of NADH oxidation and inhibition of NO2- oxidation. 3. Oligomycin inhibited NADH oxidation and stimulated the oxidation of NO2-. The concentration of oligomycin required to produce half-maximal effect in both systems was the same. 4. The apparent Km for NO2- was not affected by ADP together with Pi, by uncoupling agent or by oligomycin. 5. With NADH as substrate, classical respiratory control was observed. With NO2- as substrate the respiratory-control ratio was less than unity. 6. A reversible uptake of H+ accompanied the oxidation of NO2- by ET particles. 7. In the presence of NH4Cl or cyclohexylamine hydrochloride, H+ uptake was abolished and increased rates of NO2- oxidation were observed. When valinomycin was present in the reaction medium, low concentrations of NH4Cl inhibited NO2- oxidation. 8. Pretreatment of ET particles with oligomycin enhanced the stimulation of NO2- oxidation induced by NH4Cl or by cyclohexylamine hydrochloride. Pretreatment with the uncoupler carbonyl cyanide phenylhydrazone prevented these stimulations. 9. In the presence of dianemycin together with K+, the uptake of H+ was abolished and the rate of NO2- oxidation was increased. In contrast, in the presence of valinomycin together with K+, the uptake of H+ was increased, and the rate of NO2- oxidation decreased. 10. Sodium tetraphenylboron was found to be an inhibitor of NO2- oxidation, but caused a stimulation of NADH oxidation which was dependent on the presence of NH4Cl or cyclohexylamine hydrochloride. 11. It is concluded that the enhanced rate of NO2- oxidation observed in the absence of energy-dissipating processes clearly relates to some state before the involvement of adenine nucleotides, and it is suggested that the oxidation of NO2- generates a protonmotive force, the electrical component of which controls the rate of NO2- oxidation.


Assuntos
Nitritos/metabolismo , Nitrobacter/metabolismo , Fosforilação Oxidativa , Difosfato de Adenosina/farmacologia , Cloreto de Amônio/farmacologia , Carbonil Cianeto m-Clorofenil Hidrazona/análogos & derivados , Cicloexilaminas/farmacologia , Transporte de Elétrons/efeitos dos fármacos , Cinética , NAD/metabolismo , Nitrilas/análogos & derivados , Nitrilas/farmacologia , Oligomicinas/farmacologia , Fosforilação Oxidativa/efeitos dos fármacos , Prótons , Tetrafenilborato/farmacologia , Desacopladores/farmacologia , Valinomicina/farmacologia
15.
Biochem J ; 156(3): 493-8, 1976 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-182153

RESUMO

1. A novel component in the respiratory chain of Nitrobacter winogradskyi was identified. This component absorbs maximally at 552.5 nm when in its reduced form, has an Eo' (pH7.0) value of-110mV and undergoes reduction by a mechanism involving the transfer of a single electron. 2. Degrees of reduction of cytochromes c and a1 in electron-transport (ET) particles were monitored during the course of NO2- oxidation, and the effects of ADP together with Pi, oligomycin and of carbonyl cyanide phenylhydrazone were determined. 3. The influences of ionophorous antibiotics, NH4Cl and cyclohexylamine hydrochloride on the reductions of cytochromes c and a1 by NO2- indicate that the flow of reducing equivalents from cytochrome a1 (+350mV) to cytochrome c (+270mV) is facilitated by deltapsi, the electrical component of the protonmotive force. 4. Cytochromes c and a1 in ET particles are reduced by the non-physiological reductant KBH4 in a manner similar to that observed with the physiological reductant NO2-. 5. To account both for the observed cytochrome reductions and for the translocation of H+ ions which accompanies NO2- oxidation, a mechanism is proposed which involves the transfer of a hydride equivalent (H+ plus 2e) inward across the membrane of the ET particle in response to deltapsi.


Assuntos
Citocromos/metabolismo , Transporte de Elétrons , Nitritos/metabolismo , Nitrobacter/metabolismo , Difosfato de Adenosina/metabolismo , Cloreto de Amônio/farmacologia , Boroidretos/farmacologia , Carbonil Cianeto m-Clorofenil Hidrazona/análogos & derivados , Cicloexilaminas/farmacologia , Grupo dos Citocromos c/metabolismo , Modelos Biológicos , NAD/metabolismo , Nitrilas/análogos & derivados , Nitrilas/farmacologia , Oligomicinas/farmacologia , Oxirredução , Fosforilação Oxidativa , Fósforo/farmacologia , Desacopladores/farmacologia , Valinomicina/farmacologia
18.
J Biol Chem ; 250(1): 211-7, 1975 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-166985

RESUMO

It has been reported that cells of Candida utilis, grown in continuous culture under iron-limited conditions, develop site 1 phosphorylation, without the appearance of piericidin sensitivity and without changes in the iron-sulfur centers of NADH dehydrogenase, on aeration in the presence of cycloheximide, as well as on increasing the supply of iron during growth. These findings were reinvestigated in the present study. The parameters and properties followed during these transitions were sensitivity of NADH oxidation to piericidin, presence or absence of coupling site 1, EPR signals appearing on reduction with NADH or dithionite, the specific activities of NADH oxidase, NADH-ferricyanide reductase, and NADH-5-hydroxy-1,4-naphthoquinone (juglone) reductase, and the kinetic behavior of NADH dehydrogenase in the ferricyanide assay. Monitoring the rates of oxidation of NADH in submitochondrial particles with artificial oxidants, observing the kinetics of the ferricyanide assay, and measuring the concentration of iron-sulfur centers elicited by EPR permitted ascertaining the type of NADH dehydrogenase present and its relative concentration in different experimental situations. It was found that on gradually increasing the concentration of iron during continuous culture (transition from ironlimited to iron- and substrate-limited growth), as well as on aeration of iron-limited cells, coupling site 1, piericidin sensitivity, NADH-ferricyanide activity, and iron-sulfur centers 1 and 2 increased concurrently, with concomitant decline of NADH-juglone reductase activity. Cycloheximide prevented all these changes. Iron-sulfur centers 3 plus 4 underwent relatively little increase during these transitions. It is concluded that in both of these experimental conditions a replacement of the type of NADH dehydrogenase present in exponential phase cells by that characteristic of stationary phase cells occurs and that the appearance of site 1 phosphorylation, piercidin sensitivity, and iron-sulfur centers 1 plus 2, all associated with the latter enzyme, is a consequence of this replacement. No evidence was found for the development of coupling site 1 without the appearance of piericidin sensir th


Assuntos
Antibacterianos/farmacologia , Candida/enzimologia , Ferro/farmacologia , NADH NADPH Oxirredutases/metabolismo , Fosforilação Oxidativa/efeitos dos fármacos , Fosfotransferases/metabolismo , Piridinas/farmacologia , Aerobiose , Sítios de Ligação , Candida/efeitos dos fármacos , Candida/metabolismo , Cicloeximida/farmacologia , Ditionita , Espectroscopia de Ressonância de Spin Eletrônica , Ferricianetos , Cinética , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Naftoquinonas , Consumo de Oxigênio/efeitos dos fármacos , Ligação Proteica
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