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1.
J Gen Appl Microbiol ; 66(2): 116-120, 2020 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-32213752

RESUMEN

Heterologous production of a useful carotenoid astaxanthin was achieved in a cyanobacterium Synechocystis sp. PCC 6803 with the aid of marine bacterial genes. Astaxanthin and its intermediates emerged at high levels, whereas ß-carotene and zeaxanthin disappeared in the strain. Total carotenoid accumulation was nearly two fold compared with wild type. The astaxanthin-producing strain was capable of only growing heterotrophically, which was likely due to the absence of ß-carotene. Further enhanced accumulation was pursued by gene overexpression for possible rate-limiting steps in the biosynthesis pathway.


Asunto(s)
Caulobacteraceae/enzimología , Oxigenasas de Función Mixta/metabolismo , Oxigenasas/metabolismo , Synechocystis/genética , Synechocystis/metabolismo , Vías Biosintéticas , Caulobacteraceae/genética , Cromatografía Líquida de Alta Presión , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Ingeniería Metabólica , Microorganismos Modificados Genéticamente , Oxigenasas de Función Mixta/genética , Oxigenasas/genética , Transformación Bacteriana , Xantófilas/metabolismo
2.
J Biosci Bioeng ; 128(6): 751-754, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31253510

RESUMEN

The unicellular green microalga Haematococcus pluvialis accumulates large amounts of the red ketocarotenoid astaxanthin under stress conditions such as nitrogen deficiency. In this study, we discovered an astaxanthin accumulation in H. pluvialis cells by the addition of a synthetic cationic polymer, polyethyleneimine (PEI), into the cell culture. With an increase in PEI amount, amount of astaxanthin accumulation was increased. To investigate the mechanism for the accumulation of astaxanthin by the addition of PEI in H. pluvialis cells, we measured a localization of PEI in the cells and a production of reactive oxygen species. PEI was internalized in the cells through the negatively-charged cell walls, leading to excessive production of reactive oxygen species in the cells. Thus, the increased oxidative stress by cellular uptake of PEI resulted in the acceleration of astaxanthin accumulation in H. pluvialis.


Asunto(s)
Chlorophyta/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Polietileneimina/farmacología , Chlorophyta/metabolismo , Color , Polietileneimina/química , Especies Reactivas de Oxígeno/metabolismo , Xantófilas/metabolismo
3.
Nucl Med Biol ; 40(6): 808-15, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23701701

RESUMEN

INTRODUCTION: Amino acid PET tracers are promising for visualizing gliomas and evaluating radiochemotherapeutic effects. We compared the glioma detection and early response assessment utility between trans-1-amino-3-fluoro-1-(14)C-cyclobutanecarboxylic acid (anti-(14)C-FACBC) and (3)H-methyl-l-methionine ((3)H-Met) by simultaneously analyzing their uptake by rat gliomas treated with and without temozolomide (TMZ) in vitro and in vivo. METHODS: C6 rat gliomas were incubated with low-dose TMZ to induce chemoresistance. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay demonstrated a significantly greater surviving fraction in the TMZ-resistant subline (C6R) than in drug-naive cells (C6). The anti-(14)C-FACBC and (3)H-Met uptakes were quantified using a triple-label accumulation assay to examine the relationship between tracer uptake and proliferation ((3)H-thymidine (TdR) accumulation rate) in tumor cells. C6 and C6R cells were inoculated into the right and left basal ganglia, respectively, of rats. Efficacy of TMZ against the orthotopic gliomas was analyzed by MRI, Evans blue extravasation, anti-(14)C-FACBC and (3)H-Met autoradiography, and MIB-5 proliferation index. RESULTS: The (3)H-TdR accumulation rate and amino acid tracer (anti-(14)C-FACBC and (3)H-Met) uptake significantly decreased 48 and 72 h, respectively, after TMZ treatment in C6 but not C6R cells. Anti-(14)C-FACBC uptake correlated significantly with (3)H-Met uptake and the (3)H-TdR accumulation rate. In the intracerebral glioma model, anti-(14)C-FACBC and (3)H-Met autoradiography clearly delineated the tumor extent, which spread well beyond the high-T2-intensity and enhancing lesions visible on MRI and Evans blue extravasation. TMZ significantly decreased anti-(14)C-FACBC and (3)H-Met uptake and the MIB-5 index of C6 but not C6R tumors. TMZ inhibited tracer uptake and tumor proliferation before morphological changes on MRI. CONCLUSIONS: Anti-(14)C-FACBC, like (3)H-Met, was more sensitive than post-contrast T1-weighted MRI for detecting tumor extent and early tumor response to TMZ treatment. Anti-(18)F-FACBC should be a sensitive and precise imaging biomarker for tumor extent visualization and response assessment in glioma patients.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/tratamiento farmacológico , Ácidos Carboxílicos , Ciclobutanos , Glioma/diagnóstico , Glioma/tratamiento farmacológico , Imagen por Resonancia Magnética/métodos , Metionina/análogos & derivados , Animales , Barrera Hematoencefálica/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Ácidos Carboxílicos/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ciclobutanos/metabolismo , Dacarbazina/análogos & derivados , Dacarbazina/farmacología , Dacarbazina/uso terapéutico , Estudios de Factibilidad , Glioma/metabolismo , Glioma/patología , Masculino , Metionina/metabolismo , Permeabilidad , Ratas , Temozolomida , Resultado del Tratamiento
4.
Int J Cancer ; 121(12): 2637-45, 2007 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-17708555

RESUMEN

The aim of this study was to explore whether (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) is suitable to elucidate multidrug resistance and prediction of potentiation of antitumor agents by second-generation MDR1 inhibitors (PSC833, MS-209) in malignant brain tumors in rat. Malignant tumor cells (RG2 and C6 gliomas, Walker 256 carcinoma) were incubated with low dose vincristine (VCR) to induce multidrug resistance. MTT assay demonstrated a significant increase of surviving fractions in VCR-resistant sublines compared to those of drug-naive cells. Reverse transcriptase polymerase chain reaction revealed higher expression of MDR1 mRNA in VCR-resistant cells than drug-naive cells in each line. Volume distribution (V(d)) of (99m)Tc-MIBI was negatively correlated with MDR1 mRNA expression among drug-naive and VCR-resistant cells. MDR1 inhibitors decreased surviving fractions and increased V(d) of (99m)Tc-MIBI significantly in VCR-resistant sublines, whereas MDR1 mRNA expression was unchanged. These findings indicate that (99m)Tc-MIBI efflux was functionally suppressed by MDR1 inhibitors. Autoradiographic images of (99m)Tc-MIBI revealed higher uptake in drug-naive cells at basal ganglia compared with VCR-resistant cells at the opposite basal ganglia of rats. Oral administration of the second-generation MDR1 inhibitors significantly increased (99m)Tc-MIBI accumulation of both tumors. Therapeutic effects of VCR with or without the MDR1 inhibitors were also evaluated autoradiographically using (14)C-methyl-L-methionine ((14)C-Met) and MIB-5 index. (14)C-Met uptake and MIB-5 index of both tumors treated with VCR following the MDR1 inhibitor treatment significantly decreased compared with tumors treated with VCR alone. Analysis of (99m)Tc-MIBI accumulation is considered informative for detecting MDR1-mediated drug resistance and for monitoring the therapeutic effects of MDR1 inhibitors in malignant brain tumors.


Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/antagonistas & inhibidores , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/tratamiento farmacológico , Carcinoma 256 de Walker/diagnóstico por imagen , Carcinoma 256 de Walker/tratamiento farmacológico , Tecnecio Tc 99m Sestamibi , Tomografía Computarizada de Emisión de Fotón Único , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Autorradiografía , Neoplasias Encefálicas/metabolismo , Carcinoma 256 de Walker/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ciclosporina/farmacología , Ciclosporinas/farmacología , Citotoxinas/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Sinergismo Farmacológico , Valor Predictivo de las Pruebas , Quinolinas/farmacología , ARN Mensajero/metabolismo , Radiofármacos , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Tomografía Computarizada de Emisión de Fotón Único/métodos , Vincristina/farmacología
5.
Nature ; 434(7034): 772-7, 2005 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-15800576

RESUMEN

The type-I interferon (IFN-alpha/beta) response is critical to immunity against viruses and can be triggered in many cell types by cytosolic detection of viral infection, or in differentiated plasmacytoid dendritic cells by the Toll-like receptor 9 (TLR9) subfamily, which generates signals via the adaptor MyD88 to elicit robust IFN induction. Using mice deficient in the Irf7 gene (Irf7-/- mice), we show that the transcription factor IRF-7 is essential for the induction of IFN-alpha/beta genes via the virus-activated, MyD88-independent pathway and the TLR-activated, MyD88-dependent pathway. Viral induction of MyD88-independent IFN-alpha/beta genes is severely impaired in Irf7-/- fibroblasts. Consistently, Irf7-/- mice are more vulnerable than Myd88-/- mice to viral infection, and this correlates with a marked decrease in serum IFN levels, indicating the importance of the IRF-7-dependent induction of systemic IFN responses for innate antiviral immunity. Furthermore, robust induction of IFN production by activation of the TLR9 subfamily in plasmacytoid dendritic cells is entirely dependent on IRF-7, and this MyD88-IRF-7 pathway governs the induction of CD8+ T-cell responses. Thus, all elements of IFN responses, whether the systemic production of IFN in innate immunity or the local action of IFN from plasmacytoid dendritic cells in adaptive immunity, are under the control of IRF-7.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Interferón Tipo I/inmunología , Virosis/inmunología , Proteínas Adaptadoras Transductoras de Señales , Animales , Antígenos de Diferenciación/genética , Antígenos de Diferenciación/metabolismo , Linfocitos T CD8-positivos/inmunología , Islas de CpG/genética , Islas de CpG/inmunología , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Células Dendríticas/virología , Fibroblastos , Regulación de la Expresión Génica , Inmunidad Innata/inmunología , Factor 7 Regulador del Interferón , Proteínas de la Membrana/farmacología , Ratones , Ratones Noqueados , Factor 88 de Diferenciación Mieloide , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores Inmunológicos/deficiencia , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Receptor Toll-Like 9 , Virosis/genética
6.
No Shinkei Geka ; 33(2): 163-8, 2005 Feb.
Artículo en Japonés | MEDLINE | ID: mdl-15714962

RESUMEN

Spontaneous spinal epidural hematoma (SSEH) is a rare clinical entity. Although approximately 500 cases have been reported, controversy exists concerning timing of the treatment and the validity of decompression surgery. We recently encountered four cases of SSEH. Evacuation of the hematoma was carried out in two patients with severe or persistent neurological deficits. Other two patients were treated conservatively because of the rapid resolution of the symptoms. All four patients improved after the treatment; three patients fully recovered and one patient required rehabilitation for moderate quadriparesis. Many previous reports recommended decompression surgery within 48 hours after the onset, however, one patient in our series fully recovered after surgery 4 days after the onset. We reviewed 183 operative cases of SSEH with incomplete neurological deficits in the literature and found that 93% of the patients who underwent surgery more than 48 hours after symptom onset showed good neurological recovery. Conservative treatment should be undertaken for rapidly improving patients, but surgical intervention should be considered in symptomatic patients regardless of the time from the onset.


Asunto(s)
Hematoma Espinal Epidural/cirugía , Médula Espinal/cirugía , Adolescente , Anciano , Femenino , Hematoma Espinal Epidural/diagnóstico , Hematoma Espinal Epidural/fisiopatología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Factores de Tiempo , Resultado del Tratamiento
7.
Proc Natl Acad Sci U S A ; 101(43): 15416-21, 2004 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-15492225

RESUMEN

Toll-like receptor (TLR) activation is central to immunity, wherein the activation of the TLR9 subfamily members TLR9 and TLR7 results in the robust induction of type I IFNs (IFN-alpha/beta) by means of the MyD88 adaptor protein. However, it remains unknown how the TLR signal "input" can be processed through MyD88 to "output" the induction of the IFN genes. Here, we demonstrate that the transcription factor IRF-7 interacts with MyD88 to form a complex in the cytoplasm. We provide evidence that this complex also involves IRAK4 and TRAF6 and provides the foundation for the TLR9-dependent activation of the IFN genes. The complex defined in this study represents an example of how the coupling of the signaling adaptor and effector kinase molecules together with the transcription factor regulate the processing of an extracellular signal to evoke its versatile downstream transcriptional events in a cell. Thus, we propose that this molecular complex may function as a cytoplasmic transductional-transcriptional processor.


Asunto(s)
Antígenos de Diferenciación/fisiología , Proteínas de Unión al ADN/fisiología , Glicoproteínas de Membrana/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores Inmunológicos/fisiología , Transducción de Señal/fisiología , Factores de Transcripción/fisiología , Transcripción Genética , Transducción Genética , Proteínas Adaptadoras Transductoras de Señales , Animales , Línea Celular , Transferencia de Energía , Fluorescencia , Humanos , Factor 7 Regulador del Interferón , Interferón-alfa/genética , Ratones , Factor 88 de Diferenciación Mieloide , Regiones Promotoras Genéticas , Receptor Toll-Like 7 , Receptor Toll-Like 9 , Receptores Toll-Like
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