Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Materials (Basel) ; 17(11)2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38894014

RESUMEN

Permeable pavement is a technology that allows rainwater to infiltrate into the pavement. Permeable pavements not only help reduce surface runoff by allowing rainwater to infiltrate into the pavement, but also improve water quality with the filter layer that removes particulate matter pollutants. This study evaluated the particulate matter removal efficiency of bottom ash-sand mixtures as filter layers for removing fine (≤10 µm) or ultrafine (≤2.5 µm) particulate matter in the laboratory. Five filter media were tested: silica sand, bottom ash, and bottom ash-sand mixtures with 30:70, 50:50, and 70:30 ratios. The mixed filters exhibited more consistent and stable particulate matter removal efficiency over time than either the uniform sand or bottom ash filter. The 50:50 bottom ash-sand mixture demonstrated removal rates of 58.05% for 1.8 µm particles, 93.92% for 10 µm particles, and 92.45% for 60 µm particles. These findings highlight the potential of bottom ash-sand mixtures as effective filter media for removing PM10 road dust, although field validation with actual pavement systems is necessary.

2.
Health Aff (Millwood) ; 42(12): 1697-1705, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38048509

RESUMEN

The two primary narratives that have emerged to explain low COVID-19 vaccine uptake in low- and middle-income countries are constrained accessibility and vaccine hesitancy. However, it is unclear how much each issue contributes to low uptake. This article examines these twin barriers to access. Using global survey data from 15,696 respondents across seventeen Western Pacific and African countries, collected between May 2022 and January 2023, we estimated the unmet demand for vaccines and examined its predictors. We found that among unvaccinated respondents, by the time of the survey, 50 percent had unmet demand-meaning they were still willing to get vaccinated. Rates of unmet demand were highest in African countries and lowest in Western Pacific countries. The perceived accessibility of vaccines and respondents' age and sex were identified as consistent predictors of unmet demand. These issues suggest that inequitable supply continues to play a substantial role in limiting vaccine access. Targeted efforts to increase vaccination rates are necessary, particularly in countries with low coverage and high unmet demand. Policy efforts should address barriers to vaccine access, ensure accessibility and distribution of mRNA vaccines, and aim to overcome vaccine hesitancy-all critical factors in reducing unmet immunization demand and achieving higher vaccination rates across regions.


Asunto(s)
COVID-19 , Vacunas , Humanos , Vacunas contra la COVID-19 , Países en Desarrollo , COVID-19/prevención & control , Vacunación , Inmunización
3.
Vaccine ; 41(50): 7560-7572, 2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-37977939

RESUMEN

INTRODUCTION: It is increasingly recognized that regular boosters will be necessary for the continued management of the COVID-19 pandemic. While vaccine hesitancy in the context of the initial COVID-19 vaccinations has been extensively studied, less is known about hesitancy around boosters in the post-pandemic era, where the immediate threat of COVID-19 has diminished. METHODS: Using 5,584 survey responses from people who had received at least one COVID-19 vaccine dose based on a four-round survey between May and November 2022, we examined various factors that affect booster vaccine uptake and the willingness to take an additional shot. Ordinary least squares regressions were conducted to confirm the statistical significance of the findings. RESULTS: Nearly 99% of vaccinated respondents reported having had two COVID-19 vaccine doses, while 69% of respondents reported having received a booster shot (three or more vaccine doses) and 48% reported being willing to get another shot. Booster uptake was strongly increased along with the degree of trust in the Korean Disease Control Agency (KDCA) and was also significantly associated with older age, gender, political propensity, and household income-level. When examining willingness to get an additional shot, the predictors were similar to booster vaccine uptake. However, the effect of trust in the KDCA became more salient. CONCLUSION: The factors associated with booster uptake and willingness to continue to boost are similar to those associated with initial vaccine acceptance in the ROK, namely trust in the public health authority and older age. Despite high initial uptake in the ROK, convincing the public of the continued necessity of routine immunization against COVID-19 may pose challenges in the post-pandemic era.


Asunto(s)
COVID-19 , Confianza , Humanos , Vacunas contra la COVID-19 , Pandemias/prevención & control , COVID-19/epidemiología , COVID-19/prevención & control , Salud Pública , Vacunación , República de Corea/epidemiología
4.
Am J Public Health ; 113(10): 1120-1127, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37471675

RESUMEN

Objectives. To estimate the impact of communicating to the public that men who have sex with men (MSM) are most at risk for mpox on potential stigmatization and risk perception. Methods. We conducted a survey experiment randomizing exposure to messages about mpox among a sample of the South Korean public (n = 1500) in July 2022. We randomized respondents to receive an informational message about mpox that was (1) a neutral informational message about mpox that did not highlight its origins or risk groups (control group), (2) a message explaining that the virus originated in Africa, or (3) a message emphasizing that MSM are most at risk. Results. We found that emphasizing that MSM are most at risk increases support for policies that would restrict lesbian, gay, bisexual, transgender/-sexual, queer or questioning-related events by about 7 percentage points compared with the control condition. However, the message describing African origins did not affect support for restricting travel from Africa. Neither changed risk perceptions or willingness to be vaccinated against mpox. Conclusions. Messages aimed at educating the public about most at-risk groups may trigger increased stigmatization of those groups in ways that could contribute to unnecessary persecution. (Am J Public Health. 2023;113(10):1120-1127. https://doi.org/10.2105/AJPH.2023.307347).


Asunto(s)
Mpox , Minorías Sexuales y de Género , Femenino , Humanos , Masculino , Bisexualidad , Homosexualidad Masculina , Encuestas y Cuestionarios
5.
Public Health Rep ; 138(1_suppl): 72S-77S, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37226949

RESUMEN

OBJECTIVES: Little research has compared the demographic and practice characteristics of registered nurses (RNs) who work in public health (PH RNs) with other RNs and advanced practice registered nurses (APRNs) who work in public health (PH APRNs) with other APRNs. We examined differences in characteristics between PH RNs and other RNs and between PH APRNs and other APRNs. METHODS: Using the 2018 National Sample Survey of Registered Nurses (N = 43 960), we examined demographic and practice characteristics, training needs, job satisfaction, and wages of PH RNs compared with other RNs and PH APRNs compared with other APRNs. We used independent sample t tests to determine significant differences between PH RNs and other RNs and between PH APRNs and other APRNs. RESULTS: On average, PH RNs and PH APRNs earned significantly less than other RNs ($7082 difference) and APRNs ($16 362 difference) (both P < .001). However, their job satisfaction was comparable. PH RNs and PH APRNs were also significantly more likely than other RNs and APRNs to report the need for more training in social determinants of health (20 [P < .001] and 9 [P = .04] percentage points higher, respectively), working in medically underserved communities (25 and 23 percentage points higher, respectively [P < .001 for both]), population-based health (23 and 20 percentage points higher, respectively [P < .001 for both]), and mental health (13 and 8 percentage points higher, respectively [P < .001 for both]). CONCLUSIONS: Efforts that expand public health infrastructure and workforce development must consider the value of a diverse public health nursing workforce to protect community health. Future studies should include more detailed analyses of PH RNs and PH APRNs and their roles.


Asunto(s)
Enfermería de Práctica Avanzada , Enfermeras y Enfermeros , Humanos , Salud Pública , Renta , Satisfacción en el Trabajo
6.
PLoS One ; 17(12): e0277043, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36516173

RESUMEN

Racial identity and political partisanship have emerged as two important social correlates of hesitancy towards COVID-19 vaccines in the United States. To examine the relationship of these factors with respondents' intention to vaccinate before the vaccine was available (November/December, 2020), we employed a multi-method approach: a survey experiment that randomized a vaccine-promotion message focused on racial equity in vaccine targeting, stepwise regression to identify predictors of hesitancy, and qualitative analysis of open-ended survey questions that capture how respondents reason about vaccination intentions. Experimental manipulation of a racial equity vaccine promotion message via an online survey experiment had no effect on intention-to-vaccinate in the full sample or in racial, ethnic and partisan subsamples. Descriptively, we find heightened hesitancy among non-Hispanic Black respondents (OR = 1.82, p<0.01), Hispanics (OR = 1.37, p<0.05), Trump voters (OR = 1.74, p<0.01) and non-Voters/vote Other (OR = 1.50, p<0.01) compared with non-Hispanic White respondents and Biden voters. Lower trust in institutions, individualism and alternative media use accounted for heightened hesitancy in Trump voters, but not non-Hispanic Blacks and Hispanics. Older age and female gender identity also persistently predicted lower vaccine intentions. Qualitatively, we find that most hesitant responders wanted to 'wait-and-see,' driven by generalized concerns about the speed of vaccine development, and potential vaccine side-effects, but little mention of conspiracy theories. Identity appears to be an important driver of vaccinate hesitancy that is not fully explained by underlying socioeconomic or attitudinal factors; furthermore, hesitancy was not significantly affected by racial equity messages in this setting.


Asunto(s)
COVID-19 , Vacunas , Femenino , Humanos , Masculino , Intención , Vacunas contra la COVID-19 , COVID-19/prevención & control , New York , Identidad de Género , Vacunación , Encuestas y Cuestionarios
7.
Soc Sci Med ; 314: 115440, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36332532

RESUMEN

STUDY GOAL: This study examines the sources of COVID-19 vaccine hesitancy and refusal in Americans by decomposing different forms of government trust/mistrust including trust in Trump and mistrust in public health institutions. METHODS: Using linear panel regression models with data from 5,446 US adults (37,761 responses) from the Understanding America Survey, the likelihoods of vaccine hesitancy, uptake, and trust in various information sources were examined. RESULTS AND CONCLUSION: We find that the likelihoods of hesitancy and having negative perceptions of COVID-19 vaccines were consistently much higher among PHI mistrusters, showing even a stronger hesitancy than Trump trusters. This tendency has persisted over time, resulting in only 49% of PHI mistrusters having been vaccinated in the most recent survey wave. However, a large portion of PHI mistrusters still trusted physicians, family, and friends. These findings suggest that mistrust in PHIs is a salient predictor of vaccine hesitancy and reduced uptake on its own, which is compounded by trust in Trump.


Asunto(s)
COVID-19 , Confianza , Adulto , Humanos , Vacunas contra la COVID-19/uso terapéutico , Salud Pública , Vacilación a la Vacunación , COVID-19/prevención & control
8.
J Health Polit Policy Law ; 47(1): 1-25, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-34280299

RESUMEN

CONTEXT: The United States is the only high-income country that relies on employer-sponsored health coverage to insure a majority of its population. Millions of Americans lost employer-sponsored health insurance during the COVID-19-induced economic downturn. We examine public opinion toward universal health coverage policies in this context. METHODS: Through a survey of 1,211 Americans in June 2020, we examine the influence of health insurance loss on support for Medicare for All (M4A) and the Affordable Care Act (ACA) in two ways. First, we examine associations between pandemic-related health insurance loss and M4A support. Second, we experimentally prime some respondents with a vignette of a sympathetic person who lost employer-sponsored coverage during COVID-19. FINDINGS: We find that directly experiencing recent health insurance loss is strongly associated (10 pp, p < 0.01) with greater M4A support and with more favorable views of extending the ACA (19.3 pp, p < 0.01). Experimental exposure to the vignette increases M4A support by 6 pp (p = 0.05). CONCLUSIONS: In the context of the COVID-19 pandemic, situational framings can induce modest change in support for M4A. However, real-world health insurance losses are associated with larger differences in support for M4A and with greater support for existing safety net policies such as the ACA.


Asunto(s)
COVID-19 , Política de Salud , Humanos , Cobertura del Seguro , Seguro de Salud , Medicare , Pandemias , Patient Protection and Affordable Care Act , SARS-CoV-2 , Medicina Estatal , Estados Unidos , Cobertura Universal del Seguro de Salud
9.
J Health Psychol ; 27(6): 1331-1341, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-34886687

RESUMEN

Has political polarization undermined the media' informational role during the COVID-19 pandemic? Recent studies show that politicized reporting from conservative media discouraged compliance with COVID-19 guidelines in the U.S. However, greater attention to the 24-hour news cycle may make high-consumption viewers better factually informed regardless of the source. We examine how the extent of media consumption affects people's emotions, attitudes, and behaviors toward the pandemic. With an online survey of 1128 respondents, we found a strong convergence in anxiety and health-protective behaviors in more avid media viewers regardless of media outlet while finding a divergence in attitudes toward specific mitigation strategies.


Asunto(s)
COVID-19 , Actitud , COVID-19/prevención & control , Humanos , Pandemias/prevención & control , Salud Pública , SARS-CoV-2 , Estados Unidos
10.
Materials (Basel) ; 14(5)2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33806435

RESUMEN

The impermeable cover in urban area has been growing due to rapid urbanization, which prevents stormwater from being naturally infiltrated into the ground. There is a higher chance of flooding in urban area covered with conventional concretes and asphalts. The permeable pavement is one of Low-Impact Development (LID) technologies that can reduce surface runoff and water pollution by allowing stormwater into pavement systems. Unlike traditional pavements, permeable pavement bases employ open-graded aggregates (OGAs) with highly uniform particle sizes. There is very little information on the engineering properties of compacted OGAs. In this study, the moduli of open-graded aggregates under various compaction energies are investigated based on the Plate Load Test (PLT) and Light-Weight Deflectometer (LWD). Artificial Neural Network (ANN) and Linear Regression (LR) models are employed for estimation of the moduli of the aggregates based on the material type and level of compaction. Overall, the moduli from PLT and LWD steeply increase until the number of roller passes reaches 4, and they gradually increase until the number of roller passes becomes 8. A set of simple linear equations are proposed to evaluate the moduli of open-graded aggregates from PLT and LWD based on the material type and the number of roller passes.

11.
Health Syst Reform ; 5(3): 209-223, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31390296

RESUMEN

The US remains the only high-income country that lacks a universal health financing system and instead relies on a fragmented system with the largest segment of the population receiving health insurance through private, voluntary employer-sponsored health insurance plans. While not "universal" in the sense of being mandatory and tax-financed, through a series of reforms, the US has managed to provide some form of health insurance coverage to 90% of the population. Yet, the high cost of this system, the insufficient coverage afforded to many, and continued concerns about equity have led to calls for a national health insurance program that can reduce costs across the board while providing high-quality coverage for all. Given the policy gridlock at the national level, the states have often sought to achieve universal health financing on their own, but these bills have met with little success so far. Why has the ideal of states as "laboratories of democracy" failed to produce policy change towards national health insurance? This article examines the prospects for the New York Health Act, a single-payer bill that would create a universal health financing plan for all New York State residents. Applying the Political Economy of Health Financing Framework, we analyze the politics of health reform in New York State and identify strategies to overcome opposition to this policy proposal. We find that while a clear political opportunity is in place, the prospects for adoption remain low given the power of symbolic politics and institutional inertia on the reform process.


Asunto(s)
Gobierno Federal , Reforma de la Atención de Salud/organización & administración , Financiación de la Atención de la Salud , Política , Cobertura Universal del Seguro de Salud/organización & administración , Humanos , New York
12.
Biotechnol Appl Biochem ; 64(1): 134-142, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26517977

RESUMEN

To improve drug delivery efficiency in cancer therapy, many researchers have recently concentrated on drug delivery systems that use anticancer drug loaded micro- or nanoparticles. In addition, induction methods, such as ultrasound, magnetic field, and infrared light, have been considered as active induction methods for drug delivery. Among these, focused ultrasound has been regarded as a promising candidate for the active induction method of drug delivery system because it can penetrate a deep site in soft tissue, and its energy can be focused on the targeted lesion. In this research, we employed focused ultrasound as an active induction method. For an anticancer drug loaded microparticles, we fabricated poly-lactic-co-glycolic acid docetaxel (PLGA-DTX) nanoparticle encapsulated alginate microbeads using the single-emulsion technique and the aeration method. To select the appropriate operating parameter for the focused ultrasound, we measured the pressure and temperature induced by the focused ultrasound at the focal area using a needle-type hydrophone and a digital thermal detector, respectively. Additionally, we conducted a simulation of focused ultrasound using COMSOL Multiphysics 4.3a. The experimental measurement results were compared with the simulation results. In addition, the drug release rates of the PLGA-DTX-encapsulated alginate microbeads induced by the focused ultrasound were tested. Through these experiments, we determined that the appropriate focused ultrasound parameter was peak pressure of 1 MPa, 10 cycle/burst, and burst period of 20 µSec. Finally, we performed the cell cytotoxicity and drug uptake test with focused ultrasound induction and found that the antitumor effect and drug uptake efficiency were significantly enhanced by the focused ultrasound induction. Thus, we confirmed that focused ultrasound can be an effective induction method for an anticancer drug delivery system.


Asunto(s)
Antineoplásicos , Sistemas de Liberación de Medicamentos/instrumentación , Sistemas de Liberación de Medicamentos/métodos , Microesferas , Ondas Ultrasónicas , Alginatos/química , Alginatos/farmacocinética , Alginatos/farmacología , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Línea Celular Tumoral , Emulsiones/química , Emulsiones/farmacocinética , Emulsiones/farmacología , Femenino , Ácido Glucurónico/química , Ácido Glucurónico/farmacocinética , Ácido Glucurónico/farmacología , Ácidos Hexurónicos/química , Ácidos Hexurónicos/farmacocinética , Ácidos Hexurónicos/farmacología , Humanos , Masculino
13.
Chem Commun (Camb) ; 51(30): 6659-62, 2015 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-25782606

RESUMEN

Hierarchical AuZn dendrites revealed electrocatalytic properties towards the glucose oxidation and the four-electron O2 reduction. The micro fuel cell using AuZn electrodes generated a power density of 2.07 and 0.29 mW cm(-2) for glucose and human whole blood. The micro film fuel cell implanted into the rat brain produced ∼0.52 V continuously operating for more than 18 days.


Asunto(s)
Fuentes de Energía Bioeléctrica , Electrodos Implantados , Glucosa/química , Oro/química , Oxígeno/química , Zinc/química , Animales , Electroquímica , Humanos , Ratas , Ratas Wistar
14.
J Nanosci Nanotechnol ; 15(10): 7582-5, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26726376

RESUMEN

We investigate the intrinsic electrical characteristics and source/drain parasitic resistance in p-type SnO TFTs fabricated using Ni electrodes based on the gated-four-probe method. Because of the relatively high work function and inexpensive price, Ni has been most frequently used as the source/drain electrode materials in p-type SnO TFTs. However, our experimental data shows that the width normalized parasitic resistances of SnO TFT with Ni electrodes are around one to three orders of magnitude higher than those in the representative n-type oxide TFT, amorphous indium- gallium-zinc oxide TFT, and are comparable with those in amorphous silicon TFTs with Mo electrodes. This result implies that the electrical performance of the short channel SnO TFT can be dominated by the source/drain parasitic resistances. The intrinsic field-effect mobility extracted without being influenced by source/drain parasitic resistance was ~2.0 cm2/Vs, which is around twice the extrinsic field-effect mobility obtained from the conventional transconductance method. The large contact resistance is believed to be mainly caused from the heterogeneous electronic energy-level mismatch between the SnO and Ni electrodes.

15.
Mol Cells ; 34(4): 393-8, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22983731

RESUMEN

Breast cancer is a clinically heterogeneous disease characterized by distinct molecular aberrations. Understanding the heterogeneity and identifying subgroups of breast cancer are essential to improving diagnoses and predicting therapeutic responses. In this paper, we propose a classification scheme for breast cancer which integrates data on differentially expressed genes (DEGs), copy number variations (CNVs) and microRNAs (miRNAs)-regulated mRNAs. Pathway information based on the estimation of molecular pathway activity is also applied as a postprocessor to optimize the classifier. A total of 250 malignant breast tumors were analyzed by k-means clustering based on the patterns of the expression profiles of 215 intrinsic genes, and the classification performances were compared with existing breast cancer classifiers including the BluePrint and the 625-gene classifier. We show that a classification scheme which incorporates pathway information with various genetic variations achieves better performance than classifiers based on the expression levels of individual genes, and propose that the identified signature serves as a basic tool for identifying rational therapeutic opportunities for breast cancer patients.


Asunto(s)
Neoplasias de la Mama/clasificación , Neoplasias de la Mama/genética , Variaciones en el Número de Copia de ADN/genética , Perfilación de la Expresión Génica , Genes Relacionados con las Neoplasias/genética , MicroARNs/genética , Transducción de Señal/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , MicroARNs/metabolismo
16.
Genes Dev ; 22(18): 2485-95, 2008 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-18794346

RESUMEN

Axon formation is fundamental for brain development and function. TSC1 and TSC2 are two genes, mutations in which cause tuberous sclerosis complex (TSC), a disease characterized by tumor predisposition and neurological abnormalities including epilepsy, mental retardation, and autism. Here we show that Tsc1 and Tsc2 have critical functions in mammalian axon formation and growth. Overexpression of Tsc1/Tsc2 suppresses axon formation, whereas a lack of Tsc1 or Tsc2 function induces ectopic axons in vitro and in the mouse brain. Tsc2 is phosphorylated and inhibited in the axon but not dendrites. Inactivation of Tsc1/Tsc2 promotes axonal growth, at least in part, via up-regulation of neuronal polarity SAD kinase, which is also elevated in cortical tubers of a TSC patient. Our results reveal key roles of TSC1/TSC2 in neuronal polarity, suggest a common pathway regulating polarization/growth in neurons and cell size in other tissues, and have implications for the understanding of the pathogenesis of TSC and associated neurological disorders and for axonal regeneration.


Asunto(s)
Axones , Proteínas Supresoras de Tumor/fisiología , Animales , Secuencia de Bases , Células Cultivadas , Cartilla de ADN , Electroporación , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Mutación , Proteínas Serina-Treonina Quinasas/metabolismo , Ratas , Proteína 1 del Complejo de la Esclerosis Tuberosa , Proteína 2 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de Tumor/genética
17.
J Biotechnol ; 127(2): 300-9, 2007 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-16919348

RESUMEN

Improvement of thermal stability of the Bacillus stearthermophilus No. 236 endo-beta-1,4-xylanase (XynA) was tried by engineering a de novo designed disulfide bridge. Disulfide design was performed firstly using the disulfide bond design program (Disulfide by Designtrade mark) to identify residue pairs having the favorable geometric characteristics for disulfide formation. Subsequently, the selected 25 amino acid pairs were filtered with the evolutionarily conserved Cys residues identified by alignment of 34 family 11 mesophilic and thermophilic xylanases, and also by doing inspection of the molecular model of the xylanases. Only one pair (Ser100 and Asn150) was finally chosen, and the respective amino acids were substituted with cysteine residues. The newly designed disulfide bridge increased thermostability of the XynA about 5 degrees C. This improved thermal stability was supported by the increase in the energy barrier for inactivation. As expected, the mutant XynA SNC demonstrated its better use in the hydrolysis of xylan at substantially higher temperatures than permitted by its native counterpart. The mutation had little influence on the catalytic efficiency and other functional properties of the XynA. In conclusion, it is evident that the strategically placed disulfide bridge has made the XynA be more effective in resisting thermal inactivation.


Asunto(s)
Disulfuros/metabolismo , Endo-1,4-beta Xilanasas/química , Endo-1,4-beta Xilanasas/metabolismo , Geobacillus stearothermophilus/enzimología , Calor , Ingeniería de Proteínas/métodos , Secuencia de Aminoácidos , Disulfuros/química , Estabilidad de Enzimas , Hidrólisis , Cinética , Datos de Secuencia Molecular , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Desnaturalización Proteica , Estructura Secundaria de Proteína , Compuestos de Sulfhidrilo/metabolismo , Termodinámica , Volumetría , Xilanos/metabolismo
18.
Biochem Biophys Res Commun ; 351(1): 153-8, 2006 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-17055461

RESUMEN

XaiF, a novel 32kDa protein encoded by the ORF located in the immediate downstream of the xynA gene of Bacillus stearothermophilus No. 236, was identified to be the xylanase-specific trans-activator. In this study, the positive effect of XaiF was confirmed to be xylanase-specific, and the results from Northern blot and in vitro transcription assays showed that the XaiF increased the xynA transcripts at post-transcriptional step. Moreover, analysis of the mRNA decay rate led to the assertion that the XaiF functions to stabilize the xynA mRNA. Intriguingly, in vitro RNA-protein binding assay and analysis using gst-xynA 3'-UTR chimeric gene constructs demonstrated that the XaiF stabilizes xynA mRNA by direct binding onto the 3'-UTR of the mRNA.


Asunto(s)
Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Geobacillus stearothermophilus/fisiología , Proteínas de Unión a Caperuzas de ARN/genética , Procesamiento Postranscripcional del ARN/fisiología
19.
Biosci Biotechnol Biochem ; 70(5): 1089-101, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16717408

RESUMEN

The Bacillus stearothermophilus no. 236 gene encoding the bifunctional enzyme HprK/P, the key regulator of carbon catabolite repression/activation (CCR/CCA) in most Gram-positive bacteria, was cloned and the (His)(6)-tagged gene product was characterized in detail. The nucleotide sequence of the hprK/P gene corresponded to an open reading frame of 951 bp that encoded a polypeptide of 316 amino acid residues with a calculated molecular mass of 35,458 Da. The deduced amino acid sequence of the B. stearothermophilus no. 236 HprK/P showed 64.5% identity with the B. subtilis enzyme, allowing us to identify two highly conserved motifs, the nucleotide binding P-loop (Walker motif A) and the HprK/P family signature sequence in the C-terminal half of the protein. Furthermore, complementation experiments showed that the cloned hprK/P gene product was functionally active in the B. subtilis cells. The purified (His)(6)-tagged B. stearothermophilus no. 236 HprK/P migrated on SDS-PAGE gel as a single species with a molecular mass of about 36 kDa, and behaved in gel filtration like a hexameric protein. The recombinant protein catalyzes the pyrophosphate (PPi)-dependent (highest activity at pH 7.0 and 40 degrees C) as well as the ATP-dependent phosphorylation of Ser46 in HPr (maximum activity at pH 8.0 and 45 degrees C). It also catalyzes the inorganic phosphate-dependent dephosphorylation (phosphorolysis) of seryl-phosphorylated HPr, optimally at pH 6.5 and 40 degrees C. BIAcore surface resonance analysis confirmed that a divalent cation, preferentially Mg(2+), was an indispensable cofactor for the three activities of the HprK/P. Fructose-1,6-bisphosphate (FBP) was observed to stimulate ATP-dependent kinase activity, while inorganic phosophate (Pi) inhibited ATP-dependent kinase activity. Mutations in the Walker motif A simultaneously abolished both types of kinase and phosphorylase activities. On the other hand, the conserved signature residues were confirmed to be involved in the PPi-dependent kinase and phosphorylase reactions.


Asunto(s)
Proteínas Bacterianas/química , Geobacillus stearothermophilus/enzimología , Proteínas Serina-Treonina Quinasas/química , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Proteínas Bacterianas/aislamiento & purificación , Secuencia de Bases , Cationes Bivalentes/química , Clonación Molecular , Fructosadifosfatos/química , Geobacillus stearothermophilus/genética , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Peso Molecular , Fosfatos/química , Fosforilasas/química , Fosforilasas/genética , Fosforilasas/aislamiento & purificación , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/aislamiento & purificación , Análisis de Secuencia de Proteína
20.
Biotechnol Lett ; 27(13): 949-53, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16091891

RESUMEN

A glass bead biofilm reactor was operated using H2 as an electron donor to remove nitrate at 150 mg NO3-N l(-1) to below detection level. The microbial community in the glass beads biofilm reactor was investigated by using denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis. In DGGE analysis of the biofilm, five bands were dominant and indicated the presence of eight beta-proteobacteria, one gamma-proteobacteria and twelve clostridia. An unculturable Hydrogenophaga sp., which is a new genus of hydrogen-oxidizing bacterium was dominant in microbial community of the biofilm reactor.


Asunto(s)
Bacterias/metabolismo , Biopelículas , Reactores Biológicos/microbiología , Nitratos/metabolismo , Bacterias/genética , Bacterias/crecimiento & desarrollo , Betaproteobacteria/genética , Betaproteobacteria/crecimiento & desarrollo , Betaproteobacteria/metabolismo , Biodiversidad , Clostridium/genética , Clostridium/crecimiento & desarrollo , Clostridium/metabolismo , Comamonadaceae/genética , Comamonadaceae/crecimiento & desarrollo , Comamonadaceae/metabolismo , ADN Bacteriano/análisis , ADN Bacteriano/genética , Electroforesis en Gel de Poliacrilamida/métodos , Gammaproteobacteria/genética , Gammaproteobacteria/crecimiento & desarrollo , Gammaproteobacteria/metabolismo , Vidrio , Hidrógeno/metabolismo , Microesferas , Nitritos/metabolismo , Filogenia , ARN Ribosómico 16S/genética , Aguas del Alcantarillado/microbiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...