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1.
Eur Radiol ; 33(6): 4214-4222, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36600123

RESUMEN

OBJECTIVES: To elucidate the change in glutamate levels in preterm infants at different gestational ages by glutamate chemical exchange saturated transfer (GluCEST) magnetic resonance imaging and to compare the difference in glutamate levels among different brain regions between very early preterm infants and middle and late preterm infants. METHODS: Fifty-three preterm infants (59% males; median gestational age = 33.6 weeks) underwent MRI, including conventional MRI and GluCEST. The original data were postprocessed in MATLAB. Correlation analysis was used to determine the relationship between the MTRasym and gestational age. The differences in MTRasym signals among different ROIs were statistically analysed by one-way analysis of variance (ANOVA). The MTRasym difference of the bilateral hemispherical ROI was compared by a paired T test. RESULTS: In all ROIs, glutamate concentration was positively correlated with gestational age. The glutamate concentration in the thalamus was higher than that in the frontal lobe in very early, middle and late preterm infants. A difference in glutamate concentration was not found in the bilateral ROIs. CONCLUSIONS: The concentration of glutamate in the brains of preterm infants of different gestational ages increased with gestational age, which may be one of the factors contributing to the higher incidence of neurodevelopmental dysfunction in very early preterm infants compared to that in middle and late preterm infants. Meanwhile, the glutamate concentrations among different brain regions were also diverse. KEY POINTS: • The glutamate concentration was positively correlated with gestational age in preterm infants of the brain. • Glutamate concentrations were dissimilar in different brain regions of preterm infants. • Glutamate concentration during the process of brain development in premature infants was not found to be asymmetric.


Asunto(s)
Enfermedades del Prematuro , Recien Nacido Prematuro , Lactante , Masculino , Recién Nacido , Humanos , Femenino , Edad Gestacional , Proyectos Piloto , Ácido Glutámico , Encéfalo/diagnóstico por imagen , Encéfalo/patología
2.
J Magn Reson Imaging ; 54(6): 1967-1976, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34291854

RESUMEN

BACKGROUND: Adjusting abnormal glutamate neurotransmission is a crucial mechanism in the treatment of depression. However, few non-invasive techniques could effectively detect changes in glutamate neurotransmitters, and no consensus exists on whether glutamate could affect resting-state function changes in depression. PURPOSE: To study the changes in glutamate chemical exchange saturation transfer (GluCEST) value in the hippocampus of rat model exposed to chronic unpredictable mild stress (CUMS), and to explore the effect of this change on the activity of hippocampal glutamatergic neurons. STUDY TYPE: Prospective animal study. ANIMAL MODEL: Twenty male Sprague-Dawley rats (200-300 g). FIELD STRENGTH/SEQUENCE: 7.0 T scanner. Fat rapid acquisition relaxation enhancement sequence for GluCEST, and echo planner imaging sequence for resting-state functional magnetic resonance imaging (rs_fMRI). ASSESSMENT: Rats were divided into two groups: CUMS group (N = 10) and control group (CTRL, N = 10). The magnetization transfer ratio asymmetry analysis was used to quantify the GluCEST data, and evaluate the rs_fMRI data through the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) analysis. STATISTICAL TESTS: A t-test was used to compare the difference in GluCEST or rs_fMRI between CUMS and CTRL groups. Spearman's correlation was applied to explore the correlation between GluCEST values and abnormal fMRI values in hippocampus. Statistical significance was set at P < 0.05. RESULTS: The GluCEST value in the left hippocampus has changed significantly (3.3 ± 0.3 [CUMS] vs. 3.9 ± 0.4 [CTRL], P < 0.05). In addition, the GluCEST value was significantly positively correlated with the ALFF values (r = 0.5, P < 0. 05, df = 7) and negatively correlated with the ReHo values (r = -0.6, P < 0.05, df = 7). DATA CONCLUSION: GluCEST technique has the feasibility of mapping glutamate changes in rat depression. Glutamate neurotransmitters are important factors affecting the abnormal function of neural activity. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 1.


Asunto(s)
Encéfalo , Ácido Glutámico , Animales , Mapeo Encefálico , Depresión/diagnóstico por imagen , Hipocampo/diagnóstico por imagen , Imagen por Resonancia Magnética , Masculino , Proyectos Piloto , Estudios Prospectivos , Ratas , Ratas Sprague-Dawley
3.
Appl Microbiol Biotechnol ; 100(24): 10331-10341, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27474022

RESUMEN

In methane-rich environments, methane-oxidizing bacteria usually occur predominantly among consortia including other types of microorganisms. In this study, artificial coal bed gas and methane gas were used to enrich mixed methanotrophic cultures from the soil of a coal mine in China, respectively. The changes in microbial community structure and function during the enrichment were examined. The microbial diversity was reduced as the enrichment proceeded, while the capacity for methane oxidation was significantly enhanced by the increased abundance of methanotrophs. The proportion of type II methanotrophs increased greatly from 7.84 % in the sampled soil to about 50 % in the enrichment cultures, due to the increase of methane concentration. After the microbial community of the cultures got stable, Methylomonas and Methylocystis became the dominant type I and type II methanotrophs, while Methylophilus was the prevailing methylotroph. The sequences affiliated with pigment-producing strains, Methylomonas rubra, Hydrogenophaga sp. AH-24, and Flavobacterium cucumis, could explain the orange appearance of the cultures. Comparing the two cultures, the multi-carbon sources in the artificial coal bed gas caused more variety of non-methanotrophic bacteria, but did not help to maintain the diversity or to increase the quantity and activity of methanotrophs. The results could help to understand the succession and interaction of microbial community in a methane-driven ecosystem.


Asunto(s)
Biota , Methylococcaceae/crecimiento & desarrollo , Methylococcaceae/aislamiento & purificación , Microbiología del Suelo , China , Methylococcaceae/clasificación
4.
Biotechnol Lett ; 34(6): 1029-32, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22395479

RESUMEN

A 700 ml membrane-aerated, stirred glass reactor equipped with four vertical baffles was constructed. Biodesulfurization of model oil (n-dodecane containing dibenzothiophene-DBT) and hydrodesulfurized diesel was carried out using Pseudomonas delafieldii strain R-8. Microbubble aeration gave an activity of 1.3 mg DBT removed g(-1) h(-1) and 277 µg sulfur g(-1) h(-1) for model oil and hydrodesulfurized diesel, respectively. These values were 1.9- and 1.6-times higher than using a traditional bubble aeration process. This is a promising method for the biodesulfurization of petroleum feedstocks.


Asunto(s)
Reactores Biológicos , Pseudomonas/crecimiento & desarrollo , Pseudomonas/metabolismo , Compuestos de Azufre/metabolismo , Aerobiosis , Cerámica , Gasolina , Tiofenos/metabolismo
5.
Front Bioeng Biotechnol ; 10: 799610, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35265592

RESUMEN

With the development of nanotechnology, a theranostics nanoplatform can have broad applications in multimodal image-guided combination treatment in cancer precision medicine. To overcome the limitations of a single diagnostic imaging mode and a single chemotherapeutic approach, we intend to combat tumor growth and provide therapeutic interventions by integrating multimodal imaging capabilities and effective combination therapies on an advanced platform. So, we have constructed IO@MnO2@DOX (IMD) hybrid nanoparticles composed of superparamagnetic iron oxide (IO), manganese dioxide (MnO2), and doxorubicin (DOX). The nano-platform could achieve efficient T2-T1 magnetic resonance (MR) imaging, switchable photoacoustic (PA) imaging, and tumor microenvironment (TME)-responsive DOX release and achieve enhanced synergism of magnetic hyperthermia and chemotherapy with PA/MR bimodal imaging. The results show that IMD has excellent heating properties when exposed to an alternating magnetic field (AMF). Therefore, it can be used as an inducer for tumor synergism therapy with chemotherapy and hyperthermia. In the TME, the IMD nanoparticle was degraded, accompanied by DOX release. Moreover, in vivo experimental results show that the smart nanoparticles had excellent T2-T1 MR and PA imaging capabilities and an excellent synergistic effect of magnetic hyperthermia and chemotherapy. IMD nanoparticles could significantly inhibit tumor growth in tumor-bearing mice with negligible side effects. In conclusion, smart IMD nanoparticles have the potential for tumor diagnosis and growth inhibition as integrated diagnostic nanoprobes.

6.
Int J Nanomedicine ; 17: 4619-4638, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36211026

RESUMEN

Introduction: Accurate tumor diagnosis is essential to achieve the ideal therapeutic effect. However, it is difficult to accurately diagnose cancer using a single imaging method because of the technical limitations. Multimodal imaging plays an increasingly important role in tumor treatment. Photodynamic therapy (PDT) has received widespread attention in tumor treatment due to its high specificity and controllable photocytotoxicity. Nevertheless, PDT is susceptible to tumor microenvironment (TME) hypoxia, which greatly reduces the therapeutic effect of tumor treatment. Methods: In this study, a novel multifunctional nano-snowflake probe (USPIO@MnO2@Ce6, UMC) for oxygen-enhanced photodynamic therapy was developed. We have fabricated the honeycomb-like MnO2 to co-load chlorin e6 (Ce6, a photosensitizer) and ultrasmall superparamagnetic iron oxide (USPIO, T1-T2 double contrast agent). Under the high H2O2 level of tumor cells, UMC efficiently degraded and triggered the exposure of photosensitizers to the generated oxygen, accelerating the production of reactive oxygen species (ROS) during PDT. Moreover, the resulting USPIO and Mn2+ allow for MR T1-T2 imaging and transformable PAI for multimodal imaging-guided tumor therapy. Results: TEM and UV-vis spectroscopy results showed that nano-snowflake probe (UMC) was successfully synthesized, and the degradation of UMC was due to the pH/ H2O2 responsive properties. In vitro results indicated good uptake of UMC in 4T-1 cells, with maximal accumulation at 4 h. In vitro and in vivo experimental results showed their imaging capability for both T1-T2 MR and PA imaging, providing the potential for multimodal imaging-guided tumor therapy. Compared to the free Ce6, UMC exhibited enhanced treatment efficiency due to the production of O2 with the assistance of 660 nm laser irradiation. In vivo experiments confirmed that UMC achieved oxygenated PDT under MR/PA imaging guidance in tumor-bearing mice and significantly inhibited tumor growth in tumor-bearing mice, exhibiting good biocompatibility and minimal side effects. Conclusion: The multimodal imaging contrast agent (UMC) not only can be used for MR and PA imaging but also has oxygen-enhanced PDT capabilities. These results suggest that UMC may have a good potential for further clinical application in the future.


Asunto(s)
Nanopartículas , Fotoquimioterapia , Animales , Línea Celular Tumoral , Medios de Contraste/farmacología , Peróxido de Hidrógeno/química , Imagen por Resonancia Magnética , Compuestos de Manganeso/química , Compuestos de Manganeso/farmacología , Ratones , Nanopartículas/química , Óxidos/química , Oxígeno/metabolismo , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/química , Especies Reactivas de Oxígeno
7.
J Ind Microbiol Biotechnol ; 38(10): 1709-18, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21442414

RESUMEN

Cr(VI) was efficiently reduced to Cr(III) by Pannonibacter phragmitetus LSSE-09 encapsulated in liquid-core alginate-carboxymethyl cellulose capsules under alkaline conditions. Taking into account the physical properties of the capsules, the activity of encapsulated cells, and total Cr(III) concentration in the supernatant, optimal conditions (0.5% w/v sodium alginate; 2% w/v sodium carboxymethyl cellulose; 0.1 M CaCl2; 30-min gelation time) for LSSE-09 encapsulation were determined. At optimal conditions, a relatively high reduction rate of 4.20 mg g ((dry weight))⁻¹ min⁻¹ was obtained. Total Cr(III) concentration in the supernatant was significantly decreased after reduction, because 63.7% of the formed soluble organo-Cr(III) compounds compared with those of free cells were captured by the relatively smaller porous structure of alginate capsules. The optimal pH value (9.0) for Cr(VI) reduction was not changed after encapsulation. In addition, encapsulated LSSE-09 showed no appreciable loss in activity after eight repeated cycles at 37°C, and 85.7% of its initial activity remained after 35-day storage at 4°C. The results suggest that encapsulated LSSE-09 in alginate-carboxymethyl cellulose capsules has potential biotechnological applications for the detoxification of Cr(VI)-contaminated wastewater.


Asunto(s)
Alginatos/química , Carboximetilcelulosa de Sodio/química , Cromo/metabolismo , Rhodobacteraceae/metabolismo , Concentración de Iones de Hidrógeno
8.
Front Oncol ; 11: 825429, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35155214

RESUMEN

PURPOSE: To develop and validate a radiomics nomogram for the prediction of clinically significant prostate cancer (CsPCa) in Prostate Imaging-Reporting and Data System (PI-RADS) category 3 lesions. METHODS: We retrospectively enrolled 306 patients within PI-RADS 3 lesion from January 2015 to July 2020 in institution 1; the enrolled patients were randomly divided into the training group (n = 199) and test group (n = 107). Radiomics features were extracted from T2-weighted imaging (T2WI), apparent diffusion coefficient (ADC) imaging, and dynamic contrast-enhanced (DCE) imaging. Synthetic minority oversampling technique (SMOTE) was used to address the class imbalance. The ANOVA and least absolute shrinkage and selection operator (LASSO) regression model were used for feature selection and radiomics signature building. Then, a radiomics score (Rad-score) was acquired. Combined with serum prostate-specific antigen density (PSAD) level, a multivariate logistic regression analysis was used to construct a radiomics nomogram. Receiver operating characteristic (ROC) curve analysis was used to evaluate radiomics signature and nomogram. The radiomics nomogram calibration and clinical usefulness were estimated through calibration curve and decision curve analysis (DCA). External validation was assessed, and the independent validation cohort contained 65 patients within PI-RADS 3 lesion from January 2020 to July 2021 in institution 2. RESULTS: A total of 75 (24.5%) and 16 (24.6%) patients had CsPCa in institution 1 and 2, respectively. The radiomics signature with SMOTE augmentation method had a higher area under the ROC curve (AUC) [0.840 (95% CI, 0.776-0.904)] than that without SMOTE method [0.730 (95% CI, 0.624-0.836), p = 0.08] in the test group and significantly increased in the external validation group [0.834 (95% CI, 0.709-0.959) vs. 0.718 (95% CI, 0.562-0.874), p = 0.017]. The radiomics nomogram showed good discrimination and calibration, with an AUC of 0.939 (95% CI, 0.913-0.965), 0.884 (95% CI, 0.831-0.937), and 0.907 (95% CI, 0.814-1) in the training, test, and external validation groups, respectively. The DCA demonstrated the clinical usefulness of radiomics nomogram. CONCLUSION: The radiomics nomogram that incorporates the MRI-based radiomics signature and PSAD can be conveniently used to individually predict CsPCa in patients within PI-RADS 3 lesion.

9.
J Biomed Nanotechnol ; 17(2): 205-215, 2021 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-33785092

RESUMEN

Imaging-guided cancer theranostic is a promising strategy for cancer diagnostic and therapeutic. Photodynamic therapy (PDT), as an approved treatment modality, is limited by the poor solubility and dispersion of photosensitizers (PS) in biological fluids. Herein, it is demonstrated that superparamagnetic iron oxide (SPIO)-based nanoparticles (SCFs), prepared by conjugated with Chlorin e6 (Ce6) and modified with folic acid (FA) on the surface, can be used as versatile drug delivery vehicles for effective PDT. The nanoparticles are great carriers for photosensitizer Ce6 with an extremely high loading efficiency. In vitro fluorescence imaging and in vivo magnetic resonance imaging (MRI) results indicated that SCFs selectively accumulated in tumor cells. Under near-infrared laser irradiation, SCFs were confirmed to be capable of inducing low cell viability of RM-1 cells In vitro and displaying efficient tumor ablation with negligible side effects in tumor-bearing mice models.


Asunto(s)
Nanopartículas , Fotoquimioterapia , Porfirinas , Animales , Línea Celular Tumoral , Clorofilidas , Compuestos Férricos , Ácido Fólico , Nanopartículas Magnéticas de Óxido de Hierro , Imagen por Resonancia Magnética , Ratones , Ratones Endogámicos BALB C , Fármacos Fotosensibilizantes/farmacología , Medicina de Precisión , Nanomedicina Teranóstica
10.
J Environ Sci (China) ; 21(9): 1237-46, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19999972

RESUMEN

Purification capacity of a faucet mounted type water filter for home use was evaluated, particularly with regard to microbiological performance under different running conditions. Biofilms were formed inside the filter, affecting the bacterial quality of the effluent water. Low flow rate, long stagnation period and high filter temperature were found favorable for bacterial growth inside. By commercial analytical profile index (API) kits, ten different bacterial species were identified in drinking water, four of which were probably contributed to the biofilm formation since they were also present in the biofilm. Fluorescence in situ hybridization (FISH) was used to confirm the API identification results, and direct viable count (DVC) method was employed to improve the sensitivity of FISH for the isolated Acinetobacter spp. and Pseudomonas putida as models. Relationship between the filter operating condition and the bacterial community alteration was partly revealed, which could provide the basic knowledge for the filter design and its practical use.


Asunto(s)
Filtración/métodos , Purificación del Agua/métodos , Biopelículas , Carbón Orgánico , Filtración/instrumentación , Hibridación Fluorescente in Situ , Purificación del Agua/instrumentación
11.
Wei Sheng Wu Xue Bao ; 47(1): 103-9, 2007 Feb.
Artículo en Zh | MEDLINE | ID: mdl-17436634

RESUMEN

From an agricultural sample taken in Chongqing, a stable methane-oxidizing mixed microbial consortium was established by enrichment culture with methane as a sole source of carbon and energy. The mixed consortium showed high capability of phenol degradation and 1,2-epoxypropane production from propene. More than 99% of phenol at an initial concentration of 600mg/L could be degraded by the mixed microbial consortium after 11 h of cultivation. The productivity of 1, 2-epoxypropane could be increased with the decrease of phosphate concentration. The concentration of 1, 2-epoxypropane produced could reach to 5.0mmol/L. The bacterial structure of the methane-oxidizing mixed microbial consortium was analyzed by pure culture isolation combining with 16S rRNA and PCR of the related MMO functional genes. The results showed that the methane-oxidizing mixed microbial consortium was composed of a type 1U methanotroph identified as Methylosinus trichosporium and at least 4 kinds of heterotrophs ( Comamonas testosteroni, Cupriavidus metallidurans, Acinetobacter junii and Stenotrophomonas maltophilia ). M. trichosporium Y9, isolated from the mixed consortium, harbored both sMMO and pMMO genes.


Asunto(s)
Bacterias/metabolismo , Metano/metabolismo , Microbiología del Suelo , Bacterias/crecimiento & desarrollo , Compuestos Epoxi/metabolismo , Methylosinus/metabolismo , Oxigenasas/genética , Oxigenasas/metabolismo , Fosfatos/farmacología
12.
FEMS Microbiol Lett ; 263(2): 136-41, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16978347

RESUMEN

In order to construct an expression system for the particulate methane mono-oxygenase (pMMO) gene (pmo), the structural gene cluster pmoCAB amplified from Methylosinus trichosporium OB3b was inserted into a shuttle vector pBS305 under the control of a dsz promoter and transformed into Rhodococcus erythropolis LSSE8-1. A stable transformant was successfully obtained using ethane as the sole carbon source. Fluorescence in situ hybridization results showed that the dsz promoter allowed the pmo genes to be transcribed in the recombinant strain. The effects of Cu2+ and Zn2+ concentrations on cell growth and pMMO activity in ethane-containing medium were examined. It was discovered that 7.5 microM Cu2+ and 1.8 microM Zn2+ were suitable to achieve high cell concentration and pMMO activity, but the amount of methanol accumulated during methane oxidation by the recombinant strain was still low.


Asunto(s)
Metano/metabolismo , Methylosinus/genética , Oxigenasas/metabolismo , Rhodococcus/enzimología , ADN Bacteriano/genética , ADN Recombinante , Expresión Génica , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Vectores Genéticos , Methylosinus/enzimología , Familia de Multigenes , Oxigenasas/genética , Rhodococcus/genética
13.
Colloids Surf B Biointerfaces ; 116: 418-23, 2014 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-24534431

RESUMEN

The bifunctional coating with antithrombotic and antimicrobial activity was developed using nattokinase (NK) and nanosilver (AgNPs). Firstly, the adsorption interactions between NK and AgNPs were confirmed, and the composite particles of NK-AgNPs were prepared by adsorption of NK with AgNPs. At 5FU/mL of NK concentration, the saturation adsorption capacity reached 24.35 FU/mg AgNPs with a high activity recovery of 97%, and adsorption by AgNPs also enhanced the heat stability and anticoagulant effect of NK. Based on the electrostatic force driven layer-by-layer self-assembly, the NK-AgNPs were further assembled with polyethylenimine (PEI) to form coating. UV-vis analysis showed that the self-assembly process was regular, and atom force microscopy analysis indicated that NK-AgNPs were uniformly embedded into the coating. The NK-AgNPs-PEI composite coating showed potent antithrombotic activity and antibacterial activity. This study developed a novel strategy to construct the bifunctional coating with antithrombotic and antimicrobial properties, and the coating material showed promising potential to be applied in the medical device.


Asunto(s)
Antibacterianos/farmacología , Bacillus subtilis/efectos de los fármacos , Materiales Biocompatibles Revestidos/farmacología , Escherichia coli/efectos de los fármacos , Fibrinolíticos/farmacología , Compuestos Organometálicos/farmacología , Adsorción , Antibacterianos/síntesis química , Antibacterianos/química , Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/química , Relación Dosis-Respuesta a Droga , Fibrinolíticos/síntesis química , Fibrinolíticos/química , Nanopartículas del Metal/química , Pruebas de Sensibilidad Microbiana , Compuestos Organometálicos/síntesis química , Compuestos Organometálicos/química , Tamaño de la Partícula , Polietileneimina/química , Plata/química , Plata/metabolismo , Relación Estructura-Actividad , Subtilisinas/química , Subtilisinas/metabolismo , Propiedades de Superficie
14.
Appl Biochem Biotechnol ; 170(3): 562-72, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23553109

RESUMEN

A novel strain of Bacillus licheniformis P-104 was isolated from Chinese soybean paste to produce a bioflocculant. The bioflocculant was confirmed as ultra-high molecular weight poly-γ-glutamic acid (γ-PGA) using Fourier transform infrared spectrum, high-performance liquid chromatography, and gel permeation chromatography with multi-angle laser light scattering. The production technology and flocculation properties of γ-PGA were investigated. By fed-batch fermentation in a 7-L bioreactor, the maximum γ-PGA yield reached 41.6 g L(-1) with a productivity rate of 1.07 g L(-1) h(-1). The flocculating activity of γ-PGA for kaolin suspension was 33.5±1.6 1/OD under the optimized flocculation conditions (6 mM Ca(2+), 1.5 mg L(-1) γ-PGA, and pH 6.0). The optimized dosage of γ-PGA for flocculation was just about 30 % of that of reported γ-PGA produced by other strains. Moreover, the flocculation activity of γ-PGA produced by strain P-104 was much higher than commercial γ-PGA with the molecular weight ranging 200-500 kDa and 1,500-2,500 kDa. This study provided a promising strain and an efficient method for production of ultra-high molecular weight γ-PGA which could be used as a potential green bioflocculant.


Asunto(s)
Bacillus/metabolismo , Peso Molecular , Ácido Poliglutámico/análogos & derivados , Bacillus/efectos de los fármacos , Bacillus/genética , Cloruro de Calcio/farmacología , Fermentación , Floculación/efectos de los fármacos , Concentración de Iones de Hidrógeno , Filogenia , Ácido Poliglutámico/biosíntesis , Glycine max/microbiología
15.
Appl Biochem Biotechnol ; 168(7): 1753-64, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22987066

RESUMEN

This study presents a novel and integrated preparation technology for nattokinase functional food, including strain screening, fermentation, separation, and encapsulation. To rapidly screen a nattokinase-productive strain, PCR-based screening method was combined with fibrinolytic activity-based method, and a high productive strain, Bacillus subtilis LSSE-22, was isolated from Chinese soybean paste. Reduction of poly-γ-glutamic acid (γ-PGA) concentration may contribute to separation of nattokinase and reduction of late-onset anaphylaxis risk. Chickpeas were confirmed as the favorable substrate for enhancement of nattokinase production and reduction of γ-PGA yield. Using cracked chickpeas, the nattokinase activity reached 356.25 ± 17.18 FU/g (dry weight), which is much higher than previous reports. To further reduce γ-PGA concentration, ethanol fractional extraction and precipitation were applied for separation of nattokinase. By extraction with 50 % and precipitation with 75 % ethanol solution, 4,000.58 ± 192.98 FU/g of nattokinase powders were obtained, and the activity recovery reached 89 ± 1 %, while γ-PGA recovery was reduced to 21 ± 2 %. To improve the nattokinase stability at acidic pH condition, the nattokinase powders were encapsulated, and then coated with methacrylic acid-ethyl acrylate copolymer. After encapsulation, the nattokinase was protected from being denatured under various acid conditions, and pH-responsible controlled release at simulated intestinal fluid was realized.


Asunto(s)
Bacillus subtilis/aislamiento & purificación , Bacillus subtilis/metabolismo , Cicer/microbiología , Fermentación , Glycine max/microbiología , Subtilisinas/biosíntesis , Acrilatos/química , Secuencia de Aminoácidos , Secuencia de Bases , Cápsulas , Precipitación Química , Cicer/enzimología , Estabilidad de Enzimas , Etanol/química , Etanol/aislamiento & purificación , Etanol/metabolismo , Fibrinólisis , Gelatina/química , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Ácidos Polimetacrílicos/química , Glycine max/enzimología , Subtilisinas/química , Subtilisinas/genética , Subtilisinas/metabolismo , Factores de Tiempo , Agua/química
16.
Appl Biochem Biotechnol ; 166(4): 933-41, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22161214

RESUMEN

Hexavalent chromate reductase was characterized and was found to be localized in the cytoplasmic fraction of a chromium-resistant bacterium Pannonibacter phragmitetus LSSE-09. The Cr(VI) reductase activity of cell-free extract (S12) was significantly improved by external electron donors, such as NADH, glucose, acetate, formate, citrate, pyruvate, and lactate. The reductase activity was optimal at pH 7.0 with NADH as the electron donor. The aerobic and anaerobic Cr(VI)-reduction enhanced by 0.1 mM NADH were respectively 3.5 and 3.4 times as high as that without adding NADH. The Cr(VI) reductase activity was inhibited by Mn²âº, Cd²âº, Fe³âº, and Hg²âº, whereas Cu²âº enhanced the chromate reductase activity by 29% aerobically and 33% anaerobically. The aerobic and anaerobic specific Michaelis-Menten constant K(m) of S12 fraction was estimated to be 64.95 and 47.65 µmol L⁻¹, respectively. The soluble S150 fractions showed similar activity to S12 and could reduce 39.7% and 53.4% of Cr(VI) after 1 h of incubation aerobically and anaerobically while the periplasmic contents showed no obvious reduction activity, suggesting an effective enzymatic mechanism of Cr(VI) reduction in the cytoplasmic fractions of the bacterium. Results suggest that the enzymatic reduction of Cr(VI) could be useful for Cr(VI) detoxification in wastewater.


Asunto(s)
Proteínas Bacterianas/metabolismo , Cromo/metabolismo , Oxidorreductasas/metabolismo , Rhodobacteraceae/química , Contaminantes Químicos del Agua/metabolismo , Aerobiosis , Anaerobiosis , Cationes/metabolismo , Fraccionamiento Celular , Cromo/química , Citosol/química , Glucosa/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Metales Pesados/metabolismo , NAD/metabolismo , Oxidación-Reducción , Oxígeno/metabolismo , Rhodobacteraceae/enzimología , Contaminantes Químicos del Agua/química
17.
Bioresour Technol ; 103(1): 273-8, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22019398

RESUMEN

Silver nanoparticles (AgNPs) were obtained by solar irradiation of cell-free extracts of Bacillusamyloliquefaciens and AgNO3. Light intensity, extract concentration, and NaCl addition influenced the synthesis of AgNPs. Under optimized conditions (solar intensity 70,000 lx, extract concentration 3 mg/mL, and NaCl content 2 mM), 98.23±0.06% of the Ag+ (1 mM) was reduced to AgNPs within 80 min, and the ζ-potential of AgNPs reached -70.84±0.66 mV. TEM (Transmission electron microscopy) and XRD (X-ray diffraction) analysis confirmed that circular and triangular crystalline AgNPs with mean diameter of 14.6 nm were synthesized. Since heat-inactivated extracts also mediated the formation of AgNPs, enzymatic reactions are likely not involved in AgNPs formation. A high absolute ζ-potential value of the AgNPs, possibly caused by interaction with proteins likely explains the high stability of AgNPs suspensions. AgNPs showed antimicrobial activity against Bacillussubtilis and Escherichiacoli in liquid and solid medium.


Asunto(s)
Bacillus/metabolismo , Bacillus/efectos de la radiación , Nanopartículas del Metal/química , Plata/metabolismo , Luz Solar , Antibacterianos/biosíntesis , Antibacterianos/farmacología , Bacillus subtilis/efectos de los fármacos , Bacillus subtilis/crecimiento & desarrollo , Escherichia coli/efectos de los fármacos , Escherichia coli/crecimiento & desarrollo , Nanopartículas del Metal/ultraestructura , Pruebas de Sensibilidad Microbiana , Nitrato de Plata/farmacología , Cloruro de Sodio/farmacología , Espectrofotometría Ultravioleta
18.
Bioresour Technol ; 102(15): 7349-53, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21612919

RESUMEN

Methanol was produced from methane with a high conversion rate using a high cell density process with Methylosinus trichosporium OB3b in the presence of a high concentration of phosphate buffer. More than 1.1 g/L methanol accumulated in the reaction media under optimized reaction conditions (17 g dry cell/L, 400 mmol/L phosphate, and 10 mmol/L MgCl(2)) in the presence of 20 mmol/L sodium formate. The conversion rate of methane was over 60%. About 0.95 g/L methanol was produced when the biotransformation was carried out in a membrane aerated reactor into which methane and oxygen were introduced via two separate dense silicone tubing. Our results provide an efficient method and a promising process for high-rate conversion of methane to methanol.


Asunto(s)
Metano/metabolismo , Metanol/metabolismo , Methylosinus trichosporium/metabolismo , Aerobiosis/efectos de los fármacos , Reactores Biológicos/microbiología , Formiatos/farmacología , Cloruro de Magnesio/farmacología , Membranas Artificiales , Methylosinus trichosporium/citología , Methylosinus trichosporium/efectos de los fármacos , Fosfatos/farmacología , Factores de Tiempo
19.
J Agric Food Chem ; 59(8): 3957-63, 2011 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-21391672

RESUMEN

To develop safe and cheap thrombolytic agents, a fibrinolytic enzyme productive strain of LSSE-62 was isolated from Chinese soybean paste. This strain was identified as Bacillus amyloliquefaciens by 16S rDNA sequence analysis. Nucleotide and amino acid sequence analysis showed that this fibrinolytic enzyme was identical to subtilisin DJ-4. Chickpeas were used as the substrate for fibrinolytic enzyme production from B. amyloliquefaciens in solid-state fermentation. Under the optimized conditions (34 °C and 50% initial moisture content), the fibrinolytic activity of fermented chickpeas reached 39.28 fibrin degradation units (FU)/g. Additionally, the fermented chickpeas showed anticoagulant activity, and the purified anticoagulant component showed higher anticoagulant activity than heparin sodium. After fermentation, the total phenolic and total flavonoid contents increased by 222 and 71%, respectively, and then the antioxidant activities were improved significantly. This study provided a novel method for the preparation of multifunctional food of chickpeas or raw materials for the preparation of functional food additives and potential drugs.


Asunto(s)
Anticoagulantes/farmacología , Antioxidantes/farmacología , Bacillus/enzimología , Cicer , Fermentación , Fibrinólisis , Secuencia de Aminoácidos , Bacillus/clasificación , Bacillus/genética , Secuencia de Bases , Clonación Molecular , Cartilla de ADN , ADN Ribosómico/genética , Evaluación Preclínica de Medicamentos , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Homología de Secuencia de Aminoácido
20.
J Hazard Mater ; 185(2-3): 1169-76, 2011 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-21041020

RESUMEN

A novel Cr (VI) resistant bacterial strain LSSE-09, identified as Pannonibacter phragmitetus, was isolated from industrial sludge. It has strong aerobic and anaerobic Cr (VI)-reduction potential under alkaline conditions. At 37 °C and pH 9.0, growing cells of strain LSSE-09 could completely reduce 100 and 1000 mg L(-1) Cr (VI)-Cr (III) within 9 and 24h, respectively under aerobic condition. Resting cells showed higher anaerobic reduction potential with the rate of 1.46 mg g(-1)((dry weight))min(-1), comparing with their aerobic reduction rate, 0.21 mg g(-1)min(-1). External electron donors, such as lactate, acetate, formate, pyruvate, citrate and glucose could highly increase the reduction rate, especially for aerobic reduction. The presence of 3000 mg L(-1) acetate enhanced anaerobic and aerobic Cr (VI)-reduction rates up to 9.47 mg g(-1)min(-1) and 4.42 mg g(-1)min(-1), respectively, which were 5 and 20 times faster than those without it. Strain LSSE-09 retained high activities over six batch cycles and NO(3)(-) and SO(4)(2-) had slightly negative effects on Cr (VI)-reduction rates. The results suggest that strain LSSE-09 has potential application for Cr (VI) detoxification in alkaline wastewater.


Asunto(s)
Álcalis/metabolismo , Cromo/metabolismo , Proteobacteria/metabolismo , Electrones , Concentración de Iones de Hidrógeno , Oxidación-Reducción
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