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1.
Intern Med ; 63(2): 305-307, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37225489

RESUMO

The patient was 57 years old when he was diagnosed with amyotrophic lateral sclerosis (ALS) at 1 year after developing bulbar symptoms. At 58 years old, he stated that he was considering donating his kidney to his son suffering from diabetic nephropathy. We confirmed the patient's intentions through repeated interviews before his death at 61 years old. Nephrectomy was performed 30 min after his cardiac death. Organ donation spontaneously proposed by an ALS patient should be considered in order to meet the requests of patients who want their families and other patients to live longer, thereby imparting a beneficial legacy through their deaths.


Assuntos
Esclerose Lateral Amiotrófica , Obtenção de Tecidos e Órgãos , Masculino , Humanos , Pessoa de Meia-Idade , Esclerose Lateral Amiotrófica/cirurgia , Autopsia , Rim
2.
Transplant Proc ; 52(6): 1639-1642, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32471629

RESUMO

BACKGROUND: Liver transplantation from donors after cardiac death (DCD) could increase the pool of organs. We previously reported that oxygenated subnormothermic (20°C-25°C) ex vivo liver perfusion (SELP) improved the graft viability in rats. This study aimed to compare the effectiveness of SELP and normothermic (37°C) ex vivo liver perfusion (NELP) after cold storage (CS) in DCD liver grafts. METHODS: Male Wistar rats were used, and grafts were retrieved 30 minutes after cardiac arrest. We performed oxygenated NELP and SELP with a Krebs-Henseleit buffer for different time points and durations: Group 0, donation performed from heart-beating donors (control); Group 1 (DCD group), donation performed from DCD donors with no treatments; Group 2, NELP performed before CS (30 minutes); Group 3, NELP performed after CS (30 minutes); Group 4, SELP performed after CS (30 minutes); Group 5, SELP performed after CS (60 minutes); and Group 6, SELP performed after CS (90 minutes). After 15 minutes of incubation at room temperature, the grafts were reperfused under normothermic conditions for 60 minutes as a model of liver transplantation. RESULTS: No significant differences in body and liver weight were observed between all groups. In the SELP after CS groups, even 30 minutes of perfusion improved bile production, tumor necrosis factor-α, and interleukin-1ß significantly compared with the DCD group (P < .05), comparable with NELP groups. CONCLUSION: SELP rescued DCD livers from ischemia-reperfusion injury the same as the normothermic perfusion before or after CS groups. SELP after CS is more convenient than normothermic perfusion; hence, this technique may increase the organ pool.


Assuntos
Criopreservação , Transplante de Fígado/métodos , Fígado , Perfusão/métodos , Animais , Masculino , Ratos , Ratos Wistar
3.
Surg Today ; 50(6): 615-622, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31797128

RESUMO

PURPOSE: Enhanced recovery after surgery (ERAS) protocols are becoming the standard of care in many surgical procedures, although data on their use following hepatectomy for hepatocellular carcinoma (HCC) are scarce. This study aimed to evaluate the effects of a new ERAS pathway in terms of the patient nutrition status after hepatectomy for HCC. METHODS: This is a retrospective analysis of 97 consecutive patients treated with open or laparoscopic hepatectomy for HCC between January 2011 and August 2014. We compared the perioperative outcomes between patients whose treatment incorporated the ERAS pathway and control patients. The nutritional status was evaluated using the controlling nutritional status score. RESULTS: The length of hospital stay (LOS) after both open and laparoscopic hepatectomy was shorter for the ERAS group than the control group. The days of ambulation and cessation of intravenous infusion were earlier and the postoperative nutrition status was statistically better in the ERAS group than in the control group. A multivariate analysis showed that being in the non-ERAS group was a risk factor of delayed discharge. There were no marked differences in the rate of severe complications between the two groups. CONCLUSIONS: The ERAS pathway seems feasible and safe and results in a faster recovery, reduced LOS, improved nutrition status, and fewer severe complications.


Assuntos
Carcinoma Hepatocelular/fisiopatologia , Carcinoma Hepatocelular/terapia , Recuperação Pós-Cirúrgica Melhorada , Hepatectomia/métodos , Neoplasias Hepáticas/fisiopatologia , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Estudos Retrospectivos , Segurança , Resultado do Tratamento
4.
Gan To Kagaku Ryoho ; 41(5): 653-5, 2014 May.
Artigo em Japonês | MEDLINE | ID: mdl-24917016

RESUMO

A 51-year-old man presented with a chief complaint of constipation. Rectal cancer was detected up to 13 cm proximal to the anal verge. The cancer was a fully circumferential type II tumor that was accompanied by prostate invasion and lymph node metastasis. After sigmoid colostomy, preoperative chemoradiotherapy with S-1/irinotecan (CPT-11; total 50 Gy) was administered, resulting in tumor volume reduction. However, because of residual invasion in some parts of the prostate, therapy with capecitabine and oxaliplatin (XELOX) plus bevacizumab was added to avoid pelvic exenteration. Because magnetic resonance imaging revealed no invasion prostate after 7 courses of the therapy, abdominoperineal resection of the rectum was performed. Pathological examination revealed no residual tumor cells, and a pathological complete response was thus confirmed. The addition of chemotherapy to preoperative chemoradiotherapy was considered to be an effective strategy for locally advanced rectal cancer in this case.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimiorradioterapia , Neoplasias Retais/terapia , Anticorpos Monoclonais Humanizados/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Bevacizumab , Camptotecina/administração & dosagem , Camptotecina/análogos & derivados , Capecitabina , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Combinação de Medicamentos , Fluoruracila/administração & dosagem , Fluoruracila/análogos & derivados , Humanos , Irinotecano , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Oxaloacetatos , Ácido Oxônico/administração & dosagem , Neoplasias Retais/patologia , Tegafur/administração & dosagem
5.
FEMS Microbiol Lett ; 350(2): 154-60, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24236444

RESUMO

The Per-ARNT-Sim (PAS) domain serine/threonine kinase PAS kinase is involved in energy flux and protein synthesis. In yeast, PSK1 and PSK2 are two partially redundant PASK homologs. We recently generated PSK2 deletion mutant and showed that Psk2 acts as a nutrient-sensing protein kinase to modulate Ultradian clock-coupled respiratory oscillation in yeast. Here, we show that deletion of PSK1 increased the sensitivity of yeast cells to oxidative stress (H2 O2 treatment) and partially inhibited cell growth; however, the growth of the PSK2-deleted mutant was similar to that of the wild type. Superoxide dismutase-1 (SOD1) mRNA and protein levels were lower in PSK1-deletion mutant than the wild type. The mRNA levels of stress response genes CTT1, HSP104, ATH1, NTH1 and SOD2 were similar in both the PSK1-deleted mutant and wild-type yeast. Furthermore, intracellular accumulation of reactive oxygen species (ROS) was noted in PSK1-deleted mutant. These results suggest that PSK1 induces SOD1 expression to protect against oxidative stress in yeast.


Assuntos
Regulação Fúngica da Expressão Gênica/genética , Estresse Oxidativo/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Superóxido Dismutase/genética , Mutação/genética , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Superóxido Dismutase/metabolismo , Superóxido Dismutase-1
6.
Arch Biochem Biophys ; 509(1): 52-8, 2011 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-21345330

RESUMO

Ultradian clock-coupled respiratory oscillation (UCRO) in an aerobic continuous culture of Saccharomyces cerevisiae S288C is principally regulated by control of certain redox reactions of energy metabolism. It is also modulated by the metabolism of storage carbohydrates during adaptation to environmental change. However, the mechanism of cell sensing and response to environmental nutrients in UCRO is unknown. The purpose of the present study was to determine the role of PSK2 kinase in UCRO in yeast. S. cerevisiae in culture showed oscillation in PSK2 mRNA levels with a definite phase relationship to the respiratory oscillation. Furthermore, inactivation of Psk2 by gene disruption severely affected UCRO and its decline to undetectable levels within 2days. In addition, the extracellular and intracellular glucose concentrations of PSK2 deletion mutants in culture were higher and lower, respectively, than those of the wild type. PSK2 mutant cells showed no alteration in redox state. Furthermore, the levels of storage carbohydrates such as glycogen and trehalose fluctuated in PSK2 mutants with attenuated amplitudes comparable to those in the wild type. The results indicated that PSK2 kinase is important for the uptake of glucose and regulation of storage-carbohydrate synthesis and hence the maintenance of an unperturbed continuously oscillating state.


Assuntos
Glucose/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Relógios Biológicos , Metabolismo dos Carboidratos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mutação , Proteínas Serina-Treonina Quinases/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética
7.
Biochem Biophys Res Commun ; 379(2): 621-5, 2009 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-19126402

RESUMO

Three trehalases ATH1, NTH1, and NTH2 have been identified in Saccharomyces cerevisiae. ATH1, and NTH1 hydrolyze trehalose to glucose to provide energy and assist in recovery from stress. Human trehalase (TREH) is expressed in the intestine and kidney and probably hydrolyzes ingested trehalose in the intestine and acts as marker of renal tubular damage in kidney. Since trehalose is not present in circulation or kidney tubules, its renal effect suggests it has other yet unidentified actions. Here we examined the function of human trehalase in budding yeast. We constructed three yeast trehalase mutants (NTH1Delta, NTH2Delta, and ATH1Delta) and then transformed TREH into these mutants. NTH1Delta did not grow on media containing trehalose as the carbon source, and TREH did not rectify NTH1Delta dysfunction and also did not grow on trehalose medium, suggesting that TREH is not responsible for utilization of exogenous trehalose in yeast. In experiments involving exposure to heat, osmotic and oxidative stresses, NTH1Delta showed no recovery. Interestingly, ATH1Delta-TREH showed high sensitivity to all three stressors. ATH1Delta and NTH2Delta showed very low neutral trehalase activity and NTH1Delta did not show any neutral trehalase activity, and trehalose concentrations were higher. Increased neutral trehalase activity (equivalent to the wild type), reduction of trehalose content and brisk sensitivity to stressors were noted in TREH-ATH1Delta strain, but not in TREH-NTH1Delta or -NTH2Delta. Our results suggest that TREH acts as a stress-response protein in the kidney rather than involved in utilization of exogenous trehalose.


Assuntos
Resposta ao Choque Térmico , Pressão Osmótica , Estresse Oxidativo , Saccharomyces cerevisiae/enzimologia , Trealase/metabolismo , Sequência de Bases , Carbono/metabolismo , Teste de Complementação Genética , Resposta ao Choque Térmico/genética , Humanos , Rim/enzimologia , Mutação , Estresse Oxidativo/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Proteínas de Saccharomyces cerevisiae/genética , Trealase/genética , Trealose/metabolismo
8.
FEBS Lett ; 581(21): 3991-5, 2007 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-17673205

RESUMO

We investigated the participation of HDACs in VPA induced apoptosis in Saccharomyces cerevisiae. VPA (20 mM) induced apoptosis in several HDAC mutants, including PRD3 and HDA1-disrupted cells and SIR2 over expressing cells, as well as in wild-type cells but not SIR2-disrupted cells. Intracellular reactive oxygen species and neutral lipid content increased markedly in all kinds of HDAC mutant cells tested except for SIR2-disrupted cells. Thus, these results suggest that 20 mM VPA induces neutral lipid accumulation and apoptosis-like features in S. cerevisiae, and that VPA-induced apoptosis was evaded by deletion of SIR2.


Assuntos
Apoptose/fisiologia , Inibidores Enzimáticos/farmacologia , Histona Desacetilases/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/metabolismo , Sirtuínas/metabolismo , Ácido Valproico/farmacologia , Apoptose/efeitos dos fármacos , Deleção de Genes , Histona Desacetilases/deficiência , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/fisiologia , Lipídeos/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Proteínas Reguladoras de Informação Silenciosa de Saccharomyces cerevisiae/deficiência , Sirtuína 2 , Sirtuínas/deficiência
9.
J Pharmacol Sci ; 103(3): 317-22, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17341842

RESUMO

We have reported that chronically administered pravastatin prevented coronary artery reperfusion-induced lethal ventricular fibrillation (VF) in anesthetized rats without lowering the serum cholesterol level. The present study was undertaken to evaluate whether pravastatin prevents ischemia-induced lethal VF, simultaneously examining myeloperoxidase (MPO) activity in ischemic myocardial tissues. Anesthetized rats were subjected to 30-min ischemia and 60-min reperfusion after chronic administration of pravastatin (0.02, 0.2, and 2 mg/kg), fluvastatin (2 and 4 mg/kg), or vehicle for 22 days, orally, once daily. ECG and blood pressure were continually recorded, and MPO was measured by a spectrophotometer. Pravastatin and fluvastatin significantly (P<0.05) decreased MPO activities, but only pravastatin decreased the incidence of ischemia-induced lethal VF. Both statins had no significant effects on body weight, blood pressure, heart rate, and QT interval as we reported earlier. Our results prove further that pravastatin has benefits to decrease cardiovascular mortality beyond its cholesterol-lowering effect. Pravastatin is more potent than fluvastatin in prevention of arrhythmias. A decrease in the neutrophil infiltration may be partly involved in the inhibitory effect of pravastatin on the ischemia-induced VF.


Assuntos
Arritmias Cardíacas/prevenção & controle , Vasos Coronários/fisiopatologia , Hidroximetilglutaril-CoA Redutases/uso terapêutico , Isquemia/etiologia , Pravastatina/uso terapêutico , Administração Oral , Anestesia , Animais , Arritmias Cardíacas/sangue , Relação Dose-Resposta a Droga , Esquema de Medicação , Ácidos Graxos Monoinsaturados/administração & dosagem , Ácidos Graxos Monoinsaturados/uso terapêutico , Fluvastatina , Hidroximetilglutaril-CoA Redutases/administração & dosagem , Indóis/administração & dosagem , Indóis/uso terapêutico , Isquemia/fisiopatologia , Masculino , Peroxidase/metabolismo , Pravastatina/administração & dosagem , Ratos , Ratos Sprague-Dawley
10.
FEBS Lett ; 579(3): 723-7, 2005 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-15670835

RESUMO

Valproic acid (VPA) inhibited the growth of yeast in a dose-dependent manner with complete inhibition attained at 100 mM. When cells were exposed to 25 mM VPA, the wild-type died showing apoptotic markers, while yca1Delta deleted of YCA1 encoding yeast caspase 1 survived. On the other hand, when cells were exposed to 50 mM VPA, both the wild-type and yca1Delta died showing morphological features similar to those of the autophagic death of cdc28 which was also independent of YCA1. Thus, these results suggested that yeast cells die via YCA1-dependent apoptosis when their proliferative activity is mildly impaired.


Assuntos
Apoptose/efeitos dos fármacos , Proliferação de Células , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/efeitos dos fármacos , Ácido Valproico/farmacologia , Autofagia , Biomarcadores , Saccharomyces cerevisiae/citologia
11.
Surg Today ; 35(1): 76-9, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15622469

RESUMO

We used video-assisted thoracoscopic surgery to successfully treat primary chylopericardium, a very rare disease. A 27-year-old woman was admitted to our hospital for investigation of cardiomegaly and dyspnea on exertion. Echocardiography showed severe peri-cardial effusion. A milky fluid was extracted by pericardiocentesis and diagnosed as being chylous. A computed tomography (CT) scan taken after lymphangiography showed the leakage of contrast solution into the pericardial cavity. Initially, conservative therapy was used to treat the condition, but this proved ineffective and we decided to perform video-assisted thoracoscopic surgery. The thoracic duct was ligated and excised, and partial pericardiectomy was carried out under thoracoscopy. The patient has been in good health with no sign of recurrence since her operation. Thus, video-assisted thoracoscopic thoracic duct ligation and partial pericardiectomy can be effectively used to treat primary chylopericardium.


Assuntos
Quilotórax/diagnóstico , Quilotórax/cirurgia , Pericardiectomia/métodos , Cirurgia Torácica Vídeoassistida/métodos , Adulto , Ecocardiografia Doppler , Feminino , Seguimentos , Humanos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Cuidados Pré-Operatórios/métodos , Radiografia Torácica , Medição de Risco , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X , Resultado do Tratamento
12.
Biochem Biophys Res Commun ; 308(1): 152-8, 2003 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12890494

RESUMO

Fluid shear stress has been shown to modulate various endothelial functions. We selected a shear stress-specific clone, identified as collagen XII, from a bovine aortic endothelial cell (BAEC) cDNA library. We confirmed that shear stress induces collagen XII expression at both the mRNA and protein levels in cultured BAECs and human umbilical vein ECs (HUVECs) by stimulating transcription. When HUVECs were exposed to shear stress, they secreted collagen XII protein and it was deposited underneath them. Strong expression of collagen XII was found in the intima of human aortic wall lacking atherosclerotic lesions, whereas weak expression was seen in the intima of atherosclerotic plagues. Furthermore, the downstream portion of atherosclerotic plaques showed apparently weak collagen XII expression compared with the upstream portion. These results suggest that collagen XII expression induced by fluid shear stress may play a role in stabilizing the vascular structure and preventing the formation of atherosclerotic lesions.


Assuntos
Arteriosclerose/genética , Colágeno Tipo XII/genética , Endotélio Vascular/metabolismo , Estresse Mecânico , Animais , Arteriosclerose/patologia , Sequência de Bases , Bovinos , Células Cultivadas , Primers do DNA , DNA Complementar , Endotélio Vascular/patologia , Humanos , Imuno-Histoquímica , Reação em Cadeia da Polimerase , RNA Mensageiro/genética
13.
FEMS Microbiol Lett ; 223(1): 141-5, 2003 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-12799013

RESUMO

We report herein that the level of reactive oxygen species (ROS) observed using dihydrorhodamine is much higher in either GTS1-deleted (gts1Delta) or GTS1-overexpressing (TMpGTS1) transformants than in the wild-type and that the levels of protein carbonyls are increased and the glutathione levels are decreased in both transformants. Consistently, the activities of superoxide dismutases (SODs) in both gts1Delta and TMpGTS1 were severely weakened, while the protein levels of both Cu/Zn-SOD and Mn-SOD were not so changed. As the intracellular copper levels were significantly increased in both transformants, we hypothesized that, in either gts1Delta or TMpGTS1 cells, the imbalanced homeostasis of copper induced an accumulation of ROS which caused inactivation of SODs further increasing ROS levels.


Assuntos
Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Superóxido Dismutase/metabolismo , Fatores de Transcrição/genética , Cobre/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Espécies Reativas de Oxigênio/metabolismo
14.
Eur J Biochem ; 269(14): 3560-9, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12135496

RESUMO

We previously reported that GTS1 is involved in regulating ultradian oscillations of the glycolytic pathway induced by cyanide in cell suspensions as well as oscillations of energy metabolism in aerobic continuous cultures. Here, we screened a yeast cDNA library for proteins that bind to Gts1p using the yeast two-hybrid system and cloned multiple TDH cDNAs encoding the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We found that the zinc-finger and dimerization sites of Gts1p were required for full ability to bind GAPDH, and Gts1ps mutated at these sites lost the ability to regulate both aerobic and unaerobic ultradian oscillations of energy metabolism. Of the three TDH genes, only TDH1 fluctuated at the mRNA level in continuous culture and its deletion resulted in the disappearance of the oscillation without any affect on growth rate. This loss of biological rhythms in the TDH1-deleted mutant was rescued by the expression of TDH1 but not of TDH2 or TDH3 under the control of the TDH1 promoter. Thus, we hypothesized that Gts1p plays a role in the regulation of metabolic oscillation by interacting with the TDH1 product, GAPDH1, in yeast.


Assuntos
Relógios Biológicos/fisiologia , Proteínas Fúngicas/fisiologia , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/fisiologia , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomyces cerevisiae/fisiologia , Fatores de Transcrição , Antimetabólitos/farmacologia , Sítios de Ligação , Relógios Biológicos/efeitos dos fármacos , DNA Complementar/genética , DNA Fúngico/metabolismo , Dimerização , Metabolismo Energético/efeitos dos fármacos , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Regulação Fúngica da Expressão Gênica/fisiologia , Marcação de Genes , Genes Fúngicos , Teste de Complementação Genética , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/química , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/genética , Glicólise/efeitos dos fármacos , Mapeamento de Interação de Proteínas , RNA Fúngico/biossíntese , RNA Fúngico/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Proteínas Recombinantes de Fusão/fisiologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética , Cianeto de Sódio/farmacologia , Técnicas do Sistema de Duplo-Híbrido , Dedos de Zinco/fisiologia
15.
J Biol Chem ; 277(37): 33624-31, 2002 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-12070147

RESUMO

Yeast cells exhibit sustained ultradian oscillations of energy metabolism in coupling with cell cycle and stress resistance oscillations in continuous culture. We have reported that the rhythmic expression of Gts1p is important for the maintenance of ultradian rhythms. Structurally, Gts1p contains sequence motifs similar to N-degron and the ubiquitin association domain, raising the possibility that the Gts1p level is regulated by degradation via ubiquitination. When the lysine residue at the putative ubiquitination site of the N-degron was substituted with arginine, both the protein level and half-life of mutant Gts1p increased. During continuous culture, the protein level of the mutant Gts1p was elevated and did not fluctuate, leading to the disappearance of metabolic oscillation within a day. Furthermore, using three Gts1ps containing mutations in the ubiquitin association domain, we showed that the lower the binding activity of the mutant Gts1ps for polyubiquitin in vitro, the higher the protein level in vivo. Expression of the mutant Gts1ps in the continuous culture resulted in an increase in Gts1p and early loss of the oscillation. Therefore, Gts1p is degraded through conjugation with ubiquitin, and the UBA domain promoted the degradation of ubiquitinated Gts1p, causing a fluctuation in protein level, which is required for the maintenance of metabolic oscillations.


Assuntos
Saccharomyces cerevisiae/metabolismo , Ubiquitina/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Cisteína Endopeptidases/fisiologia , Dados de Sequência Molecular , Complexos Multienzimáticos/fisiologia , Complexo de Endopeptidases do Proteassoma , Ubiquitina/química
16.
Chronobiol Int ; 19(2): 361-75, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12025930

RESUMO

Heat resistance appears to cycle in concert with energy metabolism in continuous culture of the yeast Saccharomyces cerevisiae. To study the mechanism of this oscillation, the authors first examined if heat shock proteins (Hsps) are involved. Neither the protein levels of major Hsps nor the expression of the beta-galactosidase gene as a reporter under the control of the promoter carrying heat-shock element oscillated during the metabolic oscillation. The level of trehalose in yeast cycled with the same periodicity, as did energy metabolism. This oscillation was not found in a GTS1-deleted mutant that also did not show cyclic changes in heat resistance. These results suggest that heat resistance oscillation is induced by fluctuations in trehalose level and not by an oscillatory expression of Hsps. The increase in trehalose began at the start of the respiro-fermentative phase and the decrease began after the elevation of the cyclic adenosine monophosphate (cAMP) level. The authors hypothesize that the synthesis of trehalose parallels the activation of the glycolytic pathway and that trehalose is degraded by trehalase activated by cAMP coupled with the metabolic oscillation in the continuous culture of yeast.


Assuntos
Ciclos de Atividade/fisiologia , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição , Trealose/metabolismo , AMP Cíclico/metabolismo , Metabolismo Energético , Proteínas Fúngicas/genética , Genes Fúngicos , Genes Reporter , Proteínas de Choque Térmico/metabolismo , Temperatura Alta , Óperon Lac , Modelos Biológicos , Mutação , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo
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