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1.
Neuropathol Appl Neurobiol ; 46(2): 111-124, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31179566

RESUMEN

AIMS: Alterations in microenvironments are a hallmark of cancer, and these alterations in germinomas are of particular significance. Germinoma, the most common subtype of central nervous system germ cell tumours, often exhibits massive immune cell infiltration intermingled with tumour cells. The role of these immune cells in germinoma, however, remains unknown. METHODS: We investigated the cellular constituents of immune microenvironments and their clinical impacts on prognosis in 100 germinoma cases. RESULTS: Patients with germinomas lower in tumour cell content (i.e. higher immune cell infiltration) had a significantly longer progression-free survival time than those with higher tumour cell contents (P = 0.03). Transcriptome analyses and RNA in-situ hybridization indicated that infiltrating immune cells comprised a wide variety of cell types, including lymphocytes and myelocyte-lineage cells. High expression of CD4 was significantly associated with good prognosis, whereas elevated nitric oxide synthase 2 was associated with poor prognosis. PD1 (PDCD1) was expressed by immune cells present in most germinomas (93.8%), and PD-L1 (CD274) expression was found in tumour cells in the majority of germinomas examined (73.5%). CONCLUSIONS: The collective data strongly suggest that infiltrating immune cells play an important role in predicting treatment response. Further investigation should lead to additional categorization of germinoma to safely reduce treatment intensity depending on tumour/immune cell balance and to develop possible future immunotherapies.


Asunto(s)
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/inmunología , Linaje de la Célula/inmunología , Germinoma/diagnóstico , Germinoma/inmunología , Neoplasias Encefálicas/metabolismo , Perfilación de la Expresión Génica , Germinoma/metabolismo , Humanos , Pronóstico , Transcriptoma , Microambiente Tumoral/inmunología
2.
Endocrinology ; 121(2): 714-21, 1987 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-3595540

RESUMEN

[131I]Thyroglobulin [( 131I]Tg), prepared by either enzymatic iodination of human goiter Tg in vitro or isolation from the thyroids of rats previously injected with 131I, was digested with a solubilized enzyme mixture prepared from purified hog thyroid lysosomes. The digestion was performed at 37 C for 24 h under nitrogen at pH 5.0 in the presence of 4 mM dithiothreitol. Under these conditions the release of free [131I] iodoamino acids (MIT, DIT, T4, and T3) was quantitatively very similar to that observed with a standard pronase digestion procedure. To determine whether other amino acids in Tg were released as quantitatively as the iodoamino acids, free amino acids in the lysosomal digest were measured, and total free amino acid release was compared with a similar analysis performed after digestion of [131I]Tg with 6 N HCl. Total amino acid release was much less complete than iodoamino acid release, indicating preferential release of iodoamino acids from Tg by lysosomal digestion. Analysis of the lysosomal digest by HPLC on a size exclusion column indicated that Tg was degraded to peptides with a mol wt less than 4000. Assuming that the in vitro lysosomal digestion system represents a valid model for the physiological proteolytic system that degrades Tg, the results of the present study suggest that a substantial portion of the Tg in the thyroid is not degraded to free amino acids and that peptide fragments of Tg are normally present in the thyroid. In such a case, the fate and possible physiological activity of these fragments require further elucidation.


Asunto(s)
Aminoácidos/metabolismo , Lisosomas/enzimología , Tiroglobulina/metabolismo , Glándula Tiroides/ultraestructura , Animales , Humanos , Ácido Clorhídrico , Yodo/metabolismo , Radioisótopos de Yodo , Cinética , Hígado/ultraestructura , Peso Molecular , Fragmentos de Péptidos/metabolismo , Pronasa/metabolismo , Ratas , Porcinos
3.
Endocrinology ; 103(1): 254-8, 1978 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-311280

RESUMEN

Plasma immunoreactive PRL responses to indoleamines and their metabolites were studied in urethane-anesthetized rats. All drugs were injected into the lateral ventricle and blood samples were serially collected from a jugular vein. Serotonin and melatonin caused a significant increase in plasma PRL with peak values at 10-20 min after the injection. Significant increase in plasma PRL were also observed after the administration of 5-hydroxykynurenamine (5-HK), a newly identified serotonin metabolite. The potency of 5-HK was less than that of serotonin but much greater than that of melatonin. In contrast, plasma PRL did not change significantly in response to N-acetyl-5-methoxykynurenamine, another newly identified metabolite of melatonin, or a vehicle solution. Simultaneous administration of melatonin significantly blunted the plasma PRL response to serotonin, whereas the rise in plasma PRL induced by 5-HK was not blunted by melatonin. These results suggest that indoleamines as well as their metabolites play a role in regulating PRL secretion in rats.


Asunto(s)
5-Hidroxitriptófano/farmacología , Melatonina/farmacología , Prolactina/sangre , Serotonina/farmacología , Animales , Masculino , Melatonina/análogos & derivados , Ratas , Serotonina/análogos & derivados , Relación Estructura-Actividad
4.
Int J Oncol ; 8(1): 85-90, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21544334

RESUMEN

To investigate genetic abnormalities in human non-small cell lung carcinomas (NSCLC) associated with pulmonary asbestosis as compared with nou-asbestos linked lung cancers, twenty-nine primary non-small cell lung carcinomas (NSCLC) were examined for genetic abnormalities of p16/CDKN2, p53 and ras genes by single-strand conformation polymorphism analysis of polymerase chain reaction products (PCR-SSCP) and direct sequencing. Ten specimens were obtained from autopsies in which concurrent pulmonary asbestosis was present, while 19 samples were surgical specimens from asbestosis-free patients. K-ras mutations were detected in 10% each of the cancers from both asbestosis and non-asbestosis cases. p16/CDKN2 deletions or mutations and p53 aberrations were demonstrated in 20% and 10% of tumors from asbestosis cases, whereas, 32% and 21% of the cancers, respectively, from asbestosis-free patients were positive. In conclusion, it is suggested that the enhancement of neoplasia in the lung by asbestos is not dependent on suppression of p16/CDKN2 and p53 or ras activation and therefore, that asbestosis may activate alternate tumorigenic pathways in the development of NSCLC.

5.
Chest ; 112(2): 505-10, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9266891

RESUMEN

STUDY OBJECTIVE: To assess the characteristics of airway inflammation in patients with COPD. METHODS: We measured the sputum concentration of interleukin-8 (IL-8), a chemokine involved in the migration and activation of neutrophils and eosinophils. We also measured myeloperoxidase (MPO) as a parameter of neutrophil activity and eosinophil cationic protein (ECP) as a parameter of eosinophil activity. Spontaneous sputum samples were obtained from 33 patients with stable COPD and 30 patients with asthma. Induced sputum samples were obtained from 12 normal control subjects. RESULTS: The sputum concentration of IL-8 was significantly higher in the patients with COPD than in the patients with asthma or in the control subjects (p<0.0001). Concentrations of MPO and ECP were significantly higher in the patients with COPD than in the control subjects but did not differ significantly between the patients with COPD and those with asthma. In the patients with COPD, the sputum concentration of IL-8 was significantly correlated with the concentration of MPO (r=0.55, p<0.001) and of ECP (r=0.53, p<0.01). The sputum concentration of IL-8 was negatively correlated with FEV1/FVC (r=-0.78, p<0.0001) in the COPD group. CONCLUSIONS: Results suggest the activation of both neutrophils and eosinophils in the airways of patients with COPD. It appears that IL-8 plays a primary role in this activation. The sputum concentration of IL-8 appeared to be closely associated with the degree of airflow obstruction in patients with COPD and may serve as a marker in evaluating the severity of airway inflammation, which is a risk factor for COPD.


Asunto(s)
Interleucina-8/análisis , Enfermedades Pulmonares Obstructivas/inmunología , Ribonucleasas , Esputo/inmunología , Adulto , Anciano , Asma/diagnóstico , Asma/inmunología , Asma/fisiopatología , Proteínas Sanguíneas/análisis , Estudios de Casos y Controles , Proteínas en los Gránulos del Eosinófilo , Eosinófilos/inmunología , Femenino , Humanos , Mediadores de Inflamación/análisis , Enfermedades Pulmonares Obstructivas/diagnóstico , Enfermedades Pulmonares Obstructivas/fisiopatología , Activación de Linfocitos , Masculino , Persona de Mediana Edad , Activación Neutrófila , Peroxidasa/análisis , Pruebas de Función Respiratoria , Fumar/epidemiología , Esputo/química , Esputo/citología
6.
J Biochem ; 122(1): 157-67, 1997 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9276683

RESUMEN

To investigate the molecular mechanisms that control expression of smooth muscle cell (SMC) differentiation genes, we have isolated the human SM22a gene, which is composed of five exons and four introns, spanning an approximately 6-kilobase (kb) genomic DNA at chromosome region 11q23.2. Expression of the SM22a messenger RNA was detected in serum-stimulated cell cultures including SMC, undifferentiated skeletal muscle-lineage cells, and fibroblasts, and it was down-regulated in SMC of balloon-injured atheromatous human vessels. A major transcription start site of the SM22alpha gene is located at 75 base-pairs (bp) upstream of the ATG start codon. Analysis of the 2.6 kb 5'-upstream sequence demonstrated that two CArG/SRF-boxes and two GC-box/Sp1-binding sites were present at bp -147 and -274, and at bp -233 and -1635, respectively. The nucleotide sequences of the two CArG/SRF-boxes and the proximal GC-box/Sp1 binding site are 100% conserved with those of the murine SM22alpha genes [Solway, J., Seltzer, J., Samaha, F.F., Kim, S., Alger, L.E., Niu, Q., Morriesey, E.E., Ip, H.S., and Parmacek, M.S. (1995) J. Biol. Chem. 270, 13460-13469; Kemp, P.R., Osbourn, J.K., Grainger, D.J., and Metcalf, C. (1995) Biochem. J. 310, 1037-1043]. Cell transfection assays using a luciferase reporter gene construct containing the 455-bp 5'-flanking region (positions -26 to -480) showed that methylation of the CpG dinucleotides within this segment reduces its transcriptional activity. The results imply a novel mechanism for transcriptional control of the SMC differentiation-specific gene promoter.


Asunto(s)
Cromosomas Humanos Par 11 , Citosina/metabolismo , Metilación de ADN , Proteínas de Microfilamentos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Secuencia de Aminoácidos , Animales , Arterias/metabolismo , Secuencia de Bases , Diferenciación Celular/genética , Células Cultivadas , Clonación Molecular , Regulación hacia Abajo , Regulación de la Expresión Génica , Humanos , Ratones , Datos de Secuencia Molecular , Músculo Esquelético/citología , Músculo Esquelético/metabolismo , Regiones Promotoras Genéticas , Ratas , Homología de Secuencia de Ácido Nucleico , Transcripción Genética
7.
Metabolism ; 46(9): 1044-51, 1997 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9284894

RESUMEN

Non-insulin-dependent diabetes mellitus (NIDDM) is associated histopathologically with islet amyloid deposits of which a major component is islet amyloid polypeptide (IAPP)/amylin. We examined whether endogenous IAPP controls insulin secretion via a local effect within pancreatic islets and whether overexpression of this peptide contributes to pancreatic beta-cell dysfunction in this disease. Transgenic mice expressing human IAPP in pancreatic beta cell were used in this study. Human IAPP expression did not influence the mouse proinsulin mRNA level and insulin content. Glucose-induced insulin secretion was decreased in the isolated pancreatic islets of transgenic mice. MIN6, a glucose-responsive pancreatic beta-cell line, was transfected with human IAPP cDNA by a lipofectin method. Human IAPP expression was confirmed by RNA blot and immunohistochemical analysis. In two transfectants expressing the largest amount of human IAPP, insulin secretion was increased in response to glucose stimulation; however, the magnitude of the insulin response in cells transfected with human IAPP was smaller than in control clones. Insulin content was not influenced by the expression. We conclude that endogenous IAPP inhibits insulin secretion via an autocrine effect within pancreatic islets, and that the impaired insulin secretion in this disease may be partly caused by overexpression of IAPP.


Asunto(s)
Amiloide/metabolismo , Antagonistas de Insulina/metabolismo , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Amiloide/genética , Animales , Técnicas Genéticas , Glucosa/farmacología , Humanos , Secreción de Insulina , Polipéptido Amiloide de los Islotes Pancreáticos , Islotes Pancreáticos/ultraestructura , Ratones , Ratones Transgénicos/genética , Microscopía Electrónica , ARN Mensajero/metabolismo
8.
FEMS Microbiol Lett ; 190(2): 185-90, 2000 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-11034277

RESUMEN

A bacterial strain KU-7, identified as a Pseudomonas fluorescens by 16S rDNA sequencing, was one of the 12 new isolates that are able to grow on 2-nitrobenzoate as a sole source of carbon, nitrogen, and energy. Resting cells of KU-7 were found to accumulate ammonia in the medium indicating that degradation of 2-NBA proceeds through a reductive route. Metabolite analyses by thin layer chromatography and high pressure liquid chromatography indicated that 3-hydroxyanthranilate is an intermediate of 2-nitrobenzoate metabolism in KU-7 cells. This offers an alternative route to 2-nitrobenzoate metabolism since anthranilate (2-aminobenzoate) or catechol were detected as intermediates in other bacteria. Crude extracts of KU-7 cells converted 2-nitrobenzoate to 3-hydroxyanthranilate with oxidation of 2 mol of NADPH. Ring cleavage of 3-hydroxyanthranilate produced a transient yellow product, identified as 2-amino-3-carboxymuconic 6-semialdehyde, that has a maximum absorbance at 360 nm. The initial enzymes of the 2-nitrobenzoate degradation pathway were found to be inducible since succinate-grown cells produced very low enzyme activities. A pathway for 2-nitrobenzoate degradation in KU-7 was proposed.


Asunto(s)
Ácido 3-Hidroxiantranílico/metabolismo , Nitrobenzoatos/metabolismo , Pseudomonas fluorescens/metabolismo , Biodegradación Ambiental , Medios de Cultivo , Petróleo , Pseudomonas fluorescens/crecimiento & desarrollo , Pseudomonas fluorescens/aislamiento & purificación , Microbiología del Suelo , Microbiología del Agua , Contaminación del Agua
9.
Neurosci Lett ; 196(3): 189-92, 1995 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-7501280

RESUMEN

Two types of mRNAs for neurofibromin isoforms, which are produced by Von Recklinghausen neurofibromatosis (NF1) gene, have so far been identified. In the present study, we analyzed the differential expression of the two NF1 mRNAs in 16 cases of human astrocytic tumors and in surrounding normal tissues by the RNA-polymerase chain reaction. Astrocytic tumors predominantly expressed type II NF1 mRNA, whereas it was type I isoform that was predominantly expressed in the normal tissues. These results suggested that the increased type II NF1 protein might play an important role in the growth of astrocytic tumors.


Asunto(s)
Astrocitoma/genética , Neoplasias Encefálicas/genética , Genes de Neurofibromatosis 1 , Glioblastoma/genética , Proteínas/genética , ARN Mensajero/biosíntesis , Adolescente , Adulto , Anciano , Secuencia de Bases , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Neurofibromina 1
10.
Neurosurgery ; 49(3): 637-40; discussion 640-1, 2001 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11523674

RESUMEN

OBJECTIVE: The purpose of this study was to analyze clinical data and magnetic resonance imaging (MRI) findings for patients with asymptomatic, incidentally identified syringomyelia associated with Chiari I malformations who were monitored for more than 10 years, and to clarify the natural history of these lesions. METHODS: The clinical records of nine patients who had not been surgically treated and were regularly subjected to neurological and MRI examinations were analyzed. In MRI studies, the axial diameter of the syrinx at the widest level, the longitudinal extent of the syrinx, and the extent of tonsillar herniation into the spinal canal were analyzed. As a control, MRI findings for 11 patients with symptomatic syringomyelia associated with Chiari I malformations who had been surgically treated were also analyzed, and these MRI parameters were statistically compared between the asymptomatic and symptomatic groups. RESULTS: One patient underwent surgery, because of neurological changes, 7 years after the first visit. None of the remaining patients demonstrated any neurological change during the follow-up period (11.2+/-0.7 yr), and all of them have been faring well without surgery. No statistically significant differences in MRI findings between the asymptomatic and symptomatic groups were observed. CONCLUSION: The long-term clinical courses of patients with asymptomatic, incidentally identified syringomyelia associated with Chiari I malformations were observed to be benign. MRI parameters did not provide predictable values to recommend interventional surgery. Unless changes in neurological or MRI findings are detected, early interventional surgery is not necessary.


Asunto(s)
Malformación de Arnold-Chiari/complicaciones , Malformación de Arnold-Chiari/cirugía , Encéfalo/patología , Necesidades y Demandas de Servicios de Salud/estadística & datos numéricos , Siringomielia , Adolescente , Adulto , Femenino , Estudios de Seguimiento , Cefalea/diagnóstico , Cefalea/epidemiología , Cefalea/etiología , Humanos , Imagen por Resonancia Magnética , Masculino , Procedimientos Neuroquirúrgicos/métodos , Sinusitis/diagnóstico , Sinusitis/epidemiología , Sinusitis/etiología , Siringomielia/diagnóstico , Siringomielia/etiología , Siringomielia/cirugía , Factores de Tiempo , Resultado del Tratamiento
11.
Oncol Rep ; 8(5): 1063-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11496317

RESUMEN

Antibodies against human proteins that regulate DNA replication such as Cdc6 and Mcm5 became available as a new marker of proliferation. We performed immunohistochemical analysis with MIB-1 and antibody against Cdc6 on 35 brain tumors, including tumors of neuroepithelial tissue, vestibular schwannomas, meningiomas, and pituitary adenomas. Median reactivity for MIB-1 was 8.8%, and that for Cdc6 was 55%. Reactivity in most brain tumors was significantly higher for Cdc6 than for MIB-1, but reactivity of Cdc6 was independent of tumor grade. Detection of Cdc6 expression might be useful for the estimation of proliferative activity in brain tumors.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias Encefálicas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Nucleares/metabolismo , Antígenos Nucleares , Neoplasias Encefálicas/patología , Femenino , Humanos , Técnicas para Inmunoenzimas , Antígeno Ki-67 , Masculino , Persona de Mediana Edad , Pronóstico , Análisis de Supervivencia
12.
Br J Ophthalmol ; 84(12): 1397-400, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11090481

RESUMEN

AIM: To evaluate the effects of haemodialysis on macular oedema by fluorescein angiography in patients with diabetic retinopathy and end stage renal disease. METHODS: In this prospective study, fluorescein angiography was performed on 40 eyes of 22 non-insulin dependent diabetic patients with end stage renal disease just before (baseline) and 4 weeks after the beginning of haemodialysis. The change of macular leakage was determined by evaluating the same phase of the angiograms. RESULTS: Fluorescein angiograms obtained at 4 weeks showed that macular leakage was unchanged in 28/40 eyes (70%), decreased in 4/40 eyes (10%), and increased in 8/40 eyes (20%) when compared with the baseline appearance. CONCLUSIONS: These results indicate that haemodialysis does not benefit macular leakage in diabetic patients receiving haemodialysis for end stage renal disease.


Asunto(s)
Nefropatías Diabéticas/terapia , Retinopatía Diabética/terapia , Fallo Renal Crónico/terapia , Mácula Lútea , Diálisis Renal , Anciano , Nefropatías Diabéticas/complicaciones , Retinopatía Diabética/complicaciones , Edema/complicaciones , Edema/terapia , Angiografía con Fluoresceína , Estudios de Seguimiento , Humanos , Fallo Renal Crónico/complicaciones , Persona de Mediana Edad , Estudios Prospectivos
13.
Br J Ophthalmol ; 82(7): 751-3, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9924365

RESUMEN

BACKGROUND: In a previous case report, it was shown that an increase in plasma colloid osmotic pressure induced by the removal of fluid during haemodialysis was instrumental in decreasing intraocular pressure. The relation between changes in intraocular pressure, plasma osmolarity, plasma colloid osmotic pressure, and body weight before and after haemodialysis is evaluated. METHODS: Intraocular pressure, plasma osmolarity, plasma colloid osmotic pressure, and body weight were evaluated before and after haemodialysis in 36 patients. RESULTS: Intraocular pressure and plasma osmolarity both decreased significantly after haemodialysis (p < 0.0001). Plasma colloid osmotic pressure increased significantly after haemodialysis (p < 0.0001). Body weight decreased significantly because of the removal of fluid during haemodialysis (p < 0.0001). No significant correlation was found between the change in intraocular pressure and that in plasma osmolarity (r = -0.206, p = 0.2297), whereas the change in intraocular pressure was correlated with the change in plasma colloid osmotic pressure (r = -0.510, p = 0.0012) and the change in body weight (r = 0.534, p = 0.0006). A significant correlation was found between the change in plasma colloid osmotic pressure and that in body weight (r = -0.756, p < 0.0001). CONCLUSION: The change in intraocular pressure was inversely correlated with the increase in plasma colloid osmotic pressure caused by the removal of fluid during haemodialysis.


Asunto(s)
Presión Intraocular/fisiología , Diálisis Renal , Adulto , Anciano , Anciano de 80 o más Años , Líquidos Corporales , Peso Corporal , Humanos , Persona de Mediana Edad , Concentración Osmolar , Presión Osmótica
14.
J Nat Prod ; 62(1): 5-21, 1999 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9917275

RESUMEN

Structures for 2,5-disubstituted decahydroquinolines (DHQs) are reported for the two diastereomeric pairs cis-275B (14) and cis-275B' (15) and 5-epi-trans-269AB (18) and trans-269AB (19), all isolated from skin extracts of dendrobatid frogs, and for 5-epi-cis-275B' (16) and 5-epi-trans-275B (17) found in the extracts of virgin queens of a myrmicine ant [Solenopsis (Diplorhoptrum) azteca]. Detection of such DHQs in an ant, their first reported occurrence, strengthens a dietary hypothesis for the origin of the approximately 30 DHQs that have been detected in extracts of frog skin. NMR data on the two conformers of cis-decahydroquinoline permit assignment of ring conformations and stereochemistry to cis-DHQs of the "N-endo" type or the "N-exo" type. These conformations are also assigned on whether H-8a is equatorial or axial as determined with E-COSY or 1D-HOHAHA spectra.

15.
J Biosci Bioeng ; 88(3): 264-8, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-16232609

RESUMEN

Cyclohexylamine oxidase (CHAO) from a cell extract of Brevibacterium grown on cyclohexylamine was purified 50.2-fold, to electrophoretic homogeneity, by serial chromatographies. The molecular mass of the native enzyme was estimated to be approximately 50 kDa by gel filtration and SDS-PAGE. The optimum pH was 7.4 and the stable pH range was 6.0 to 7.0. The enzyme was thermostable up to 30 degrees C. The enzyme was found to be highly specific for the deamination of alicyclic monoamines such as cyclopentylamine, cycloheptylamine, and N-methylcyclohexylamine and aliphatic monoamines, such as sec-butylamine. The apparent K(m) value for cyclohexylamine was 1.23 mM. The enzyme was inhibited by flavin enzyme inhibitors such as quinine and quinacrine. The N-terminal 27 amino acid residues were determined as Gly-Ser-Val-Thr-Pro-Asp-Pro-Asp-Val-Asp-Val-Ile-Ile-His-Gly-Ala-Gly-Ile-Ser-Gly-Ser-Ala-Ala-Ala-Lys-Ala-Leu-, revealing homology to conventional flavin-containing amine oxidases (EC 1.4.3.4).

16.
J Biosci Bioeng ; 90(4): 426-30, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-16232884

RESUMEN

The ammonia-oxidizing chemoautotrophic Nitrosomonas sp. strain K1 exhibited marked ribulose-1,5-bisphosphate carboxylase (RubisCO) activity. The RubisCO [EC 4.1.1.39] was purified as an electrophoretically homogeneous protein. The molecular mass of the enzyme was estimated to be about 460 kDa by gel filtration, and it consists of two subunits [large (L): 52.2 kDa; small (S): 13.3 kDa] as demonstrated by SDS-PAGE. This confirmed that the enzyme has an L(8)S(8) structure. The K(m) values of the enzyme for RuBP, NaHCO3, and Mg2+ were estimated to be 0.112, 0.415, and 1.063 mM, respectively. The optimum pH and temperature for its activity were approximately 7.0 and 45 degrees C. The enzyme was stable up to 45 degrees C and in a pH range from 7.0-9.0 (4 degrees C, 48 h). The enzyme activity was inhibited by Cu2+, Hg2+, N-ethylmaleimide, p-chloromercuribenzoate, and SDS (0.1 mM). The activity was also inhibited by ammonium sulfate at high concentrations (38-303 mM) but the stability of the enzyme showed no inhibition at the same ammonium sulfate concentrations. The N-terminal amino acid sequences of the large and small subunits are AIKTYQAGVKEYRQTYW QPDYVPL and AIQAYHLTKKYETFSYLPQM, respectively.

17.
J Biosci Bioeng ; 87(2): 245-8, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-16232460

RESUMEN

A high-concentration-ammonium sulfate-requiring, ammonia-oxidizing bacterium, strain K1, was newly isolated from packed tower biological deodorization plants of chicken farms. The cells of strain K1 are rods (0.1-1.0 x 1.0-2.0 microm), gram negative, obligately aerobic, and nonmotile. Colonies (1-2 mm in diameter) on a plate culture are reddish, circular, and smooth. Intracytoplasmic membranes characteristic of nitrifying bacteria are present. The G+C content of the total DNA is 48.5 mol%. The similarity of 16S rRNA (%) to N. europaea ATCC 25978T (type strain) is 93.77%. This bacterium has a higher optimal growth temperature (35 degrees C) than is usually the case and tolerance up to 40 degrees C. The optimum concentration of ammonium sulfate in the medium is 303 mM, which should make it applicable for use in deodorization plants for enhancing the efficiency of deodorization. Phosphoglycerate kinase (PGK) and triosephosphate isomerase (TIM) were found to possess high specific activities (5700 and 4 x 10(5) U/mg, respectively) compared to the activities of these enzymes in strain ATCC 25978T (300 and 14 U/mg).

18.
J Biosci Bioeng ; 91(6): 603-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-16233048

RESUMEN

Triosephosphate isomerases [TIMs, EC 5.3.1.1] were purified from two ammonia-oxidizing bacteria: Nitrosomonas sp. K1 (K1), Nitrosomonas sp. TNO632 (TNO). The molecular masses of the native enzymes were estimated to be about 53.6 (K1-TIM) and 51.9 kDa (TNO-TIM) by gel filtration, whereas SDS-PAGE produced one band for each enzyme with M(r) values of 27.1 (K1-TIM) and 26.4 kDa (TNO-TIM), respectively, suggesting that the enzymes consist of identical subunits. The apparent K(m) for d-glyceraldehyde-3-phosphate (GAP) and dihydroxyacetone phosphate (DHAP) were about 1.19 and 4.78 mM (K1-TIM), and 0.41 and 6.01 mM (TNO-TIM), respectively. The two TIMs had different pH-activity curves with an optimum pH range of 6.5 (K1-TIM) and 8.0 (TNO-TIM). The temperature optima of K1-TIM and TNO-TIM were 50-60 and 60-65 degrees C, respectively. Both enzymes were strongly inhibited by 5,5'-ditiobis at 1.0 mM. The N-terminal amino acid sequences of K1-TIM and TNO-TIM were MRAGFVAGNWKMHG (K1-TIM) and MVRTGLVAGNWKMNG (TNO-TIM). A homology of 74.1% was observed between K1-TIM and TNO-TIM.

19.
J Biosci Bioeng ; 92(3): 232-6, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-16233089

RESUMEN

An ammonia-oxidizing bacterium, strain TCH716, was isolated from alkaline soil at Harbin city, China. The cells of strain TCH716 are lobate (0.8-1.5 x 1.0-2.0 microm), gram-negative, obligately aerobic, and nonmotile. Colonies (1-2 mm in diameter) on gellan gum plate culture are reddish, circular, and smooth. The G + C content of DNA is 54.78 mol%. Its percentage of 16S rRNA gene sequence similarity (%) to Nitrosolobus multiformis ATCC 25196T (type strain) is 98.56%. This bacterium has an optimal growth temperature and pH at 30 degrees C and 8.0-8.5, respectively. The concentration of ammonium sulfate in the HEPES medium for optimum growth of this bacterium is 38 mM. Strain TCH716 was found to have a plasmid (approximately 6.5 kbp) that possessed a plasmid-linked gene for sulfonamide resistance. Phosphoglycerate kinase, RubisCO and PEPC were found to possess high specific activities compared to the activities of these enzymes in strain ATCC 25978T. In identification of strain TCH716, both morphological characteristics (compartmentalized cells) and the phylogenetic relationship based on 16S rRNA gene sequence are important. Based on results obtained, strain TCH716 belongs to the genus Nitrosolobus, and designated as Nitrosolobus sp. TCH716.

20.
Rev Sci Instrum ; 49(9): 1300, 1978 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18699306

RESUMEN

A technique is described for direct and precise monitoring of the spatial dose uniformity of an electrically scanned ion beam. The method employs a two-dimensional 10x10 array of Faraday cups, individually connected to a current integrator, to measure local dose distribution. It also employs a microprocessor for rapid data processing and topographic data display. The technique is applicable to high quality ion implantation processes as a uniformity monitor with an accuracy of 1%. In addition, a new concept for uniform ion beam scanning is proposed.

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