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1.
Respir Med Case Rep ; 38: 101673, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35694132

RESUMO

We present a case of life-threatening pneumonia caused by Pseudomonas aeruginosa (P. aeruginosa) in a healthy 67-year-old man. Rapid disseminated infection resulted in the right hemorrhagic pneumonia and bacteremia. Antimicrobial therapy had limited effects, radical pneumonectomy eventually resolved the prolonged infection. Concurrently, we explored the environmental factors responsible for fulminant P. aeruginosa infection. Multi-locus sequence typing demonstrated that P. aeruginosa isolated from the patient was identical to that collected from home whirlpool bath by the common virulent factor gene. Massive inhalation of contaminated aerosol and pathogen virulence may have synergistically contributed to the severity in this case.

2.
J Reprod Dev ; 68(1): 53-61, 2022 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-34866119

RESUMO

During cryopreservation, spermatozoa may suffer cold and cryo-induced injuries -associated with alterations in cell defense systems- that are detrimental to their function and subsequent fertility. This study aimed to determine the efficacy of supplementing the semen freezing extender with the antioxidant reduced glutathione (GSH) in cattle. Semen was collected from four bulls and diluted in a freezing extender supplemented with or without GSH (0, 1, 5, and 10 mM) before the cooling step of the cryopreservation process. After thawing, the quality of the frozen-thawed semen was investigated for motility, viability, acrosomal and DNA integrity, and subsequent embryo development after in vitro fertilization of bovine oocytes. Additionally, semen from one of the bulls was used to analyze semen antioxidative potential, sperm penetration into oocytes, male pronucleus formation rate, and embryo DNA integrity. The sperm quality varied among bulls after GSH supplementation. One bull had decreased sperm total motility, and two bulls had decreased sperm DNA integrity. GSH supplementation had positive effects on embryo development for three bulls. Two of them showed both improved cleavage and blastocyst formation rates, while the other one only showed an improved cleavage rate. We observed positive effects on early male pronucleus formation and no negative effects on DNA integrity and cell number in blastocyst stage embryos. Although the effect varies depending on individual bulls and GSH concentration, GSH supplementation in semen may improve in vitro embryo production from frozen semen.


Assuntos
Preservação do Sêmen , Animais , Bovinos , Criopreservação/veterinária , Suplementos Nutricionais , Fertilização in vitro/veterinária , Congelamento , Glutationa/farmacologia , Masculino , Sêmen , Análise do Sêmen/veterinária , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides , Espermatozoides
3.
J Toxicol Sci ; 42(6): 755-761, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29142174

RESUMO

In recent years, human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) have been widely used to develop evaluation systems for drug cardiotoxicity, including the arrhythmia caused by QT prolongation. To accurately assess the arrhythmogenic potential of drugs, associated with QT prolongation, we developed an evaluation system using hiPS-CMs and gene expression analysis. hiPS-CMs were treated with 8 arrhythmogenic and 17 non-arrhythmogenic drugs at several concentrations for 24 hr to comprehensively analyze gene expression. The results showed that 19 genes were upregulated in the arrhythmogenic drug-treated cells compared with their expression levels in the non-treated and non-arrhythmogenic drug-treated cells. The arrhythmogenic risks of the drugs were evaluated by scoring gene expression levels. The results indicated that arrhythmogenic risks could be inferred when cells were treated at a concentration 100 times higher than the maximum blood concentration of the drug. Thus, we succeeded in developing a system for evaluation of the arrhythmogenic potential of drugs using gene expression analysis.


Assuntos
Anlodipino/toxicidade , Arritmias Cardíacas/induzido quimicamente , Benzimidazóis/toxicidade , Bisoprolol/toxicidade , Avaliação Pré-Clínica de Medicamentos/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas , Síndrome do QT Longo/induzido quimicamente , Miócitos Cardíacos , Fenilpropionatos/toxicidade , Piridazinas/toxicidade , Tetrazóis/toxicidade , Transcriptoma/efeitos dos fármacos , Compostos de Bifenilo , Cardiotoxicidade , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Linagliptina/toxicidade , Naftalenos/toxicidade , Piperazinas/toxicidade , Cloridrato de Prasugrel/toxicidade , Sumatriptana/toxicidade , Regulação para Cima/efeitos dos fármacos
4.
J Vet Med Sci ; 79(6): 1103-1109, 2017 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-28442639

RESUMO

Although astaxanthin (AST) is known to be a strong antioxidant, its effects on reproductive function in domestic animals have not yet been elucidated in detail. Therefore, we investigated the effects of AST on luteal cells, which produce progesterone (P4), an important hormone for maintaining pregnancy. Luteal cells were prepared by collagenase dispersion of the corpus luteum (CL). The addition of racemic AST at a low concentration (<10 nM) to cultured bovine luteal cells increased P4 in the culture medium (P<0.05). This effect was attributed to an increase in the ability of luteal cells to produce P4 (P4/cell·DNA); however, the level of lipid peroxide (TBARS: thiobarbituric acid reactive substances) per cell did not decrease with the addition of AST, whose values were similar to that with the addition of luteinizing hormone. When optical isomers of AST (SS and RR types) were added to the culture medium, respectively, SS-AST was more effective in increasing P4 production than RR-AST. When 1 mg/kg·body weight of SS-AST derived from green algae was fed to cows for 2 weeks, its concentration in blood plasma was 10.9 nM on average, which was sufficient to expect an in vitro effect on the production of P4 in cows. These results suggested the potential of SS-AST supplements for cows to elevate luteal function.


Assuntos
Células Lúteas/efeitos dos fármacos , Progesterona/metabolismo , Animais , Bovinos , Células Cultivadas , Cromatografia Líquida de Alta Pressão/veterinária , Feminino , Células Lúteas/metabolismo , Xantofilas/farmacologia
5.
Oncol Rep ; 37(1): 66-76, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27840973

RESUMO

Epidermal growth factor receptor (EGFR) overexpression and EGFR-mediated signaling pathway dysregulation have been observed in tumors from patients with various cancers, especially non-small cell lung cancer. Thus, several anti-EGFR drugs have been developed for cancer therapy. For patients with known EGFR activating mutations (EGFR exon 19 in-frame deletions and exon 21 L858R substitution), treatment with an EGFR tyrosine kinase inhibitor (EGFR TKI; gefitinib, erlotinib or afatinib) represents standard first-line therapy. However, the clinical efficacy of these TKIs is ultimately limited by the development of acquired drug resistance such as by mutation of the gatekeeper T790 residue (T790M). To overcome this acquired drug resistance and develop novel anti-EGFR drugs, a cell-based assay system for EGFR TKI resistance mutant-selective inhibitors is required. We constructed a novel cell-based assay for the evaluation of EGFR TKI efficacy against EGFR mutation. To this end, we established non-tumorigenic immortalized breast epithelial cells that proliferate dependent on EGF (MCF 10A cells), which stably overexpress mutant EGFR. We found that the cells expressing EGFR containing the T790M mutation showed higher resistance against gefitinib, erlotinib and afatinib compared with cells expressing wild-type EGFR. In contrast, L858R mutant-expressing cells exhibited higher TKI sensitivity. The effect of T790M-selective inhibitors (osimertinib and rociletinib) on T790M mutant-expressing cells was significantly higher than gefitinib and erlotinib. Finally, when compared with commercially available isogenic MCF 10A cell lines carrying introduced mutations in EGFR, our EGFR mutant-overexpressing cells exhibited obviously higher responsiveness to EGFR TKIs depending on the underlying mutations because of the higher levels of EGFR phosphorylation in the EGFR mutant-overexpressing cells than in the isogenic cell lines. In conclusion, we successfully developed a novel cell-based assay for evaluating the efficacy of anti-EGFR drugs against EGFR mutation.


Assuntos
Antineoplásicos/isolamento & purificação , Avaliação Pré-Clínica de Medicamentos/métodos , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/genética , Inibidores de Proteínas Quinases/isolamento & purificação , Afatinib , Antineoplásicos/uso terapêutico , Técnicas de Cultura de Células , Células Cultivadas , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Cloridrato de Erlotinib/farmacologia , Gefitinibe , Humanos , Mutação , Inibidores de Proteínas Quinases/uso terapêutico , Quinazolinas/farmacologia , Transfecção
6.
Nihon Geka Gakkai Zasshi ; 114(5): 256-60, 2013 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-24167979

RESUMO

Inchinkoto (ICKT) is one of the most commonly used herbal medicines and is a hepatoprotective agent. Among the numerous chemical compounds included in ICKT, geniposide is the most abundant component. After oral intake, geniposide is converted into the active metabolite genipin by intestinal bacteria and absorbed in the portal circulation. The biological properties of ICKT and its major active ingredient genipin have been studied in numerous experiments using cells and animals. ICKT or genipin administration exerts a choleretic effect through upregulation of multidrug resistance-associated protein 2 in hepatocytes. ICKT also exerts antiapoptoic activity by inhibiting the transforming growth factor beta 1- or tumor necrosis factor alpha-dependent signaling pathway. The excessive inflammatory response induced by various forms of hepatic stress is also attenuated by ICKT preadministration. Proinflammatory cytokine-induced upregulation of inducible nitric oxide synthase is strongly attenuated by ICKT in both in vivo and in vitro experiments. Moreover, ICKT enhances antioxidant enzymes in the liver under oxidative stress. These experimental results clearly indicate the effects of ICKT on hepatic stress. To date, however, clinical data on the benefits of ICKT for liver disease are very rare. To extend the clinical applications of ICKT in humans, it is crucial to design and perform a rigorous clinical trial. In this review article, recent evidence relating to the hepatoprotective effects of ICKT in the field of basic and clinical science is summarized and discussed.


Assuntos
Colagogos e Coleréticos/administração & dosagem , Medicamentos de Ervas Chinesas/administração & dosagem , Hepatectomia , Animais , Colagogos e Coleréticos/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Medicina Baseada em Evidências , Humanos , Técnicas In Vitro , Fígado/efeitos dos fármacos , Período Pré-Operatório
7.
Neurol Med Chir (Tokyo) ; 52(4): 186-93, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22522328

RESUMO

Antiangiogenic strategy is promising for malignant glioma. Histone deacetylase inhibitors (HDACIs) are unique anticancer agents that exhibit antiangiogenic effects. The in vitro and in vivo antiangiogenic effects of HDACIs, valproic acid (VPA), were investigated in malignant glioma in the brain. In vitro, VPA preferentially inhibited endothelial cell proliferation compared to glioma cell proliferation at the optimum concentration in a dose-dependent manner. VPA reduced vascular endothelial growth factor (VEGF) secretion of glioma cells in a dose-dependent manner under both normoxic and hypoxic conditions. VPA was also found to inhibit tube formation in the angiogenesis assay. In vivo, treatment with VPA combined with irinotecan reduced the number of vessels expressing factor VIII in the brain tumor model. VPA inhibits glioma angiogenesis by direct (inhibition of endothelial cell proliferation and tube formation) and indirect (decreased secretion of VEGF by glioma cells) mechanisms. These data suggest a potential role for VPA as an adjuvant therapy for patients with malignant glioma.


Assuntos
Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Ácido Valproico/farmacologia , Inibidores da Angiogênese/uso terapêutico , Animais , Anticonvulsivantes/farmacologia , Anticonvulsivantes/uso terapêutico , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/fisiopatologia , Linhagem Celular Transformada , Linhagem Celular Tumoral , Feminino , Glioma/sangue , Glioma/fisiopatologia , Humanos , Neoplasias Experimentais/irrigação sanguínea , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/fisiopatologia , Neovascularização Patológica/fisiopatologia , Neovascularização Patológica/prevenção & controle , Ratos , Ratos Wistar , Ácido Valproico/uso terapêutico
8.
No Shinkei Geka ; 39(11): 1091-7, 2011 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-22036822

RESUMO

We report a case of a 47-year-old male who had a left frontal lobe mass with specific magnetic resonance imaging (MRI). Four years previous to his admission to our hospital, he developed acute myelocytic leukemia and he was implanted with peripheral blood stem cell transplantation. One month before his admission, he was unable to walk due to right leg motor weakness. MRI revealed a round mass lesion at the left frontal lobe. Initial diagnosis was a brain abscess, so he was administered some antibacterial drug. However, his neurological symptoms kept getting worse with increase of mass size on MRI. T1-weighted MR images showed the mass as a low intensity lesion with incomplete ring-like Gd-enhancement. T2-weighted images showed the mass as a high intensity lesion with many linear shadows inside the mass. Diffusion weighted images showed the mass as a low intensity lesion. MR spectroscopy revealed an elevation of choline and lactate peak. Differential diagnosis was glioma or demyelinating disease. At the operation, the mass was light yellow and seen to be rich with vessels. The pathological diagnosis was xanthogranuloma in the brain. Postoperative course was uneventful. The frontal residual mass lesion decreased in size and Gd-enhancement.


Assuntos
Encefalopatias/diagnóstico , Lobo Frontal , Granuloma/diagnóstico , Imageamento por Ressonância Magnética , Abscesso Encefálico/diagnóstico , Encefalopatias/cirurgia , Neoplasias Encefálicas/diagnóstico , Doenças Desmielinizantes/diagnóstico , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética , Glioma/diagnóstico , Granuloma/cirurgia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade
9.
Reprod Fertil Dev ; 23(7): 912-20, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21871210

RESUMO

The aim of the present study was to assess the effects of L-carnitine, an enhancer of lipid metabolism and mitochondrial activity, during in vitro maturation (IVM) on nuclear maturation and in vitro fertilisation of porcine follicular oocytes and subsequent embryo development. Mitochondrial functions, intracellular lipid content and reactive oxygen species (ROS) levels in oocytes were also investigated. L-carnitine supplementation in 0.6-5mgmL(-1) concentration during IVM significantly improved (P<0.05) the rates of metaphase-II (MII) stage oocytes compared with the control; however, fertilisation rates and monospermy were not improved. Although supplementation of IVM medium with L-carnitine significantly increased oocyte cleavage (P<0.05), further development to the blastocyst stage was not improved. The density of active mitochondria was significantly higher and the density of lipid droplets was significantly lower (P<0.05) in L-carnitine-treated oocytes compared with the control. Furthermore, the ROS levels in L-carnitine-treated oocytes were significantly lower than those in the control. In conclusion, enhancing mitochondrial functions by L-carnitine improved oocyte maturation and cleavage underlining the importance of lipid metabolism for nuclear and cytoplasmic maturation of porcine oocytes.


Assuntos
Carnitina/metabolismo , Núcleo Celular/metabolismo , Técnicas de Maturação in Vitro de Oócitos/veterinária , Metabolismo dos Lipídeos , Oócitos/metabolismo , Sus scrofa/metabolismo , Animais , Blastocisto/citologia , Contagem de Células/veterinária , Divisão Celular , Fenômenos Químicos , Cruzamentos Genéticos , Células do Cúmulo/fisiologia , Ectogênese , Feminino , Fertilização , Metáfase , Mitocôndrias/química , Mitocôndrias/metabolismo , Oócitos/citologia , Oócitos/enzimologia , Oogênese , Espécies Reativas de Oxigênio/metabolismo , Sus scrofa/embriologia
10.
Hepatogastroenterology ; 56(89): 240-4, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19453066

RESUMO

BACKGROUND/AIMS: Recently, complementary alternative medicine is actively performed for cancer therapy. Superfine dispersed lentinan (beta-1,3-glucan)--an oral effective form--was recently developed and available. We investigated the effectiveness of superfine dispersed lentinan in advanced pancreatic cancer patients in a multi-center study. METHODOLOGY: Twenty-nine patients with unresectable and recurrent pancreatic cancer were enrolled, and adverse events and quality of life scores were assessed. Survival times were evaluated according to results of a 3-year follow-up survey. RESULTS: Although a diarrhea of grade-1 adverse event dependent on the test article (3.4%) was observed, the symptom was remitted without any treatment. This indicates that test article was free of anything harmful. Median survival time was 12.1 months (95% confidence interval: 7.3-25.7 months) in 25 eligible patients. Five (20%) out of 25 patients were alive for 3 years. There was a significant correlation between the quality of life scores after the superfine dispersed lentinan treatment and survival times. CONCLUSIONS: A superfine dispersed lentinan is deemed safe and effective for advanced pancreatic patients' survival and improvement of quality of life. And the assessment of quality of life status after the administration of superfine dispersed lentinan is a promising prognostic predictor.


Assuntos
Antineoplásicos/uso terapêutico , Lentinano/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Administração Oral , Idoso , Antineoplásicos/administração & dosagem , Feminino , Humanos , Japão , Lentinano/administração & dosagem , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Taxa de Sobrevida , Resultado do Tratamento
11.
Hepatol Res ; 39(3): 247-55, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19054142

RESUMO

AIM: To investigate the choleretic effects of inchinkoto (ICKT) on livers of patients with biliary obstruction due to bile duct carcinoma. METHODS: Twenty-seven patients with bile duct carcinoma who were due to undergo biliary drainage and subsequent major hepatectomy were randomly assigned to preoperative ICKT (n = 13) or untreated (n = 14) groups. ICKT was administered from the day of admission until one day before surgery. Changes in bile constituents, expression of multidrug resistance-associated protein (MRP) 2, MRP3 and MRP4 in the liver, and the incidence of postoperative complications were included as end-points. RESULTS: The biliary concentration of total bilirubin was significantly increased after administration of ICKT (23.7 +/- 2.8 mg/dL before ICKT; 34.0 +/- 4.0 mg/dL after ICKT, P < 0.05). The biliary concentration of total bile acids was also significantly increased. Protein levels of MRP2 and MRP3 in the crude plasma membrane fraction of livers of treated patients were significantly higher than those without treatment. MRP2 staining in the livers of patients without ICKT treatment was weak and diffuse around the bile canaliculi, whereas staining in patients with ICKT treatment was strong and restricted to the bile canaliculi. CONCLUSION: ICKT exerts a choleretic effect on the livers of patients with biliary obstruction. This beneficial effect was associated with increased expression of MRP2. ICKT thus has therapeutic potential for treatment for obstructive cholestasis due to bile duct carcinoma.

12.
Biochemistry ; 47(36): 9505-13, 2008 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-18700726

RESUMO

Usher syndrome (USH) is a human hereditary disorder characterized by profound congenital deafness, retinitis pigmentosa, and vestibular dysfunction. Myosin VIIa has been identified as the responsible gene for USH type 1B, and a number of missense mutations have been identified in the affected families. However, the molecular basis of the dysfunction of USH gene, myosin VIIa, in the affected families is unknown to date. Here we clarified the effects of USH1B mutations on human myosin VIIa motor function for the first time. The missense mutations of USH1B significantly inhibited the actin activation of ATPase activity of myosin VIIa. G25R, R212C, A397D, and E450Q mutations abolished the actin-activated ATPase activity completely. P503L mutation increased the basal ATPase activity for 2-3-fold but reduced the actin-activated ATPase activity to 50% of the wild type. While all of the mutations examined, except for R302H, reduced the affinity for actin and the ATP hydrolysis cycling rate, they did not largely decrease the rate of ADP release from actomyosin, suggesting that the mutations reduce the duty ratio of myosin VIIa. Taken together, the results suggest that the mutations responsible for USH1B cause the complete loss of the actin-activated ATPase activity or the reduction of duty ratio of myosin VIIa.


Assuntos
Actomiosina/genética , Actomiosina/metabolismo , Dineínas/genética , Dineínas/metabolismo , Mutação de Sentido Incorreto , Miosinas/genética , Miosinas/metabolismo , Síndromes de Usher/enzimologia , Difosfato de Adenosina/genética , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/genética , Trifosfato de Adenosina/metabolismo , Ativação Enzimática/genética , Humanos , Miosina VIIa , Síndromes de Usher/genética , Síndromes de Usher/patologia
13.
J Reprod Dev ; 54(5): 321-34, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18591864

RESUMO

The present 12-month feeding study was carried out with rat groups fed a diet supplemented with meat or milk (meat/milk) derived from the progeny of clones produced by somatic cell nuclear transfer (SCNT) technology. It was conducted to obtain data concerning the chronic toxicities of these edible products during the process of development and reproduction in rats fed such products. The rats were subjected to clinical observations for general health condition and examinations such as sensory/reflex function, grip strength, motor activity, body weight, food consumption, ophthalmology and urinalysis. Moreover, sexually matured rats fed the test diets were mated and examined for items such as the reproductive performances of the dams and health of their pups. After the feeding period, factors related to rat health status, based on the findings for hematology, blood biochemistry, necropsy, organ weight and histology, were examined. There were no biologically significant differences in these factors between the rat groups fed meat/milk powder supplemented diets derived from the progeny and those fed meat/milk powder supplemented diets derived from conventionally bred cattle. Therefore, the present chronic toxicity study suggests that meat and milk derived from the progeny of SCNT cattle might be equivalent to those derived from conventionally bred cattle in use as dietary supplements for rats.


Assuntos
Ração Animal , Clonagem de Organismos , Crescimento e Desenvolvimento/fisiologia , Carne , Leite , Técnicas de Transferência Nuclear , Reprodução/fisiologia , Animais , Análise Química do Sangue , Peso Corporal/fisiologia , Bovinos , Clonagem de Organismos/métodos , Clonagem de Organismos/veterinária , Suplementos Nutricionais , Ingestão de Alimentos/fisiologia , Feminino , Crescimento e Desenvolvimento/efeitos dos fármacos , Masculino , Leite/fisiologia , Atividade Motora/fisiologia , Técnicas de Transferência Nuclear/veterinária , Pós/farmacologia , Ratos , Reprodução/efeitos dos fármacos , Fatores de Tempo , Urinálise
14.
J Biol Chem ; 281(11): 7151-60, 2006 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-16415346

RESUMO

Mutations of myosin VIIA cause deafness in various species from human and mice to Zebrafish and Drosophila. We analyzed the kinetic mechanism of the ATPase cycle of Drosophila myosin VIIA by using a single-headed construct with the entire neck domain. The steady-state ATPase activity (0.06 s(-1)) was markedly activated by actin to yield V(max) and K(ATPase) of 1.72 s(-1) and 3.2 microm, respectively. The most intriguing finding is that the ATP hydrolysis predominantly takes place in the actin-bound form (actin-attached hydrolysis) for the actomyosin VIIA ATPase reaction. The ATP hydrolysis rate was much faster for the actin-attached form than the dissociated form, in contrast to other myosins reported so far. Both the ATP hydrolysis step and the phosphate release step were significantly faster than the entire ATPase cycle rate, thus not rate-determining. The rate of ADP dissociation from actomyosin VIIA was 1.86 s(-1), which was comparable with the overall ATPase cycle rate, thus assigned to be a rate-determining step. The results suggest that Drosophila myosin VIIA spends the majority of the ATPase cycle in an actomyosin.ADP form, a strong actin binding state. The duty ratio calculated from our kinetic model was approximately 0.9. Therefore, myosin VIIA is classified to be a high duty ratio motor. The present results suggested that myosin VIIA can be a processive motor to serve cargo trafficking in cells once it forms a dimer structure.


Assuntos
Dineínas/fisiologia , Miosinas/fisiologia , Actinas/química , Actomiosina/química , Difosfato de Adenosina/química , Adenosina Trifosfatases/química , Trifosfato de Adenosina/química , Animais , Clonagem Molecular , Dimerização , Relação Dose-Resposta a Droga , Drosophila , Dineínas/química , Eletroforese em Gel de Poliacrilamida , Humanos , Hidrólise , Cinética , Magnésio/química , Camundongos , Modelos Químicos , Mutação , Miosina VIIa , Miosinas/química , Fosfatos/química , Ligação Proteica , Isoformas de Proteínas , Fatores de Tempo
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