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1.
Bioresour Bioprocess ; 11(1): 28, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38647905

RESUMO

The endophytic fungus Aspergillus sp. SPH2 was isolated from the stems of the endemic plant Bethencourtia palmensis and its extracts were found to have strong fungicidal effects against Botrytis cinerea and ixodicidal effects against Hyalomma lusitanicum at different fermentation times. In this study, the fungus was grown using three different culture media and two methodologies, Microparticulate Enhancement Cultivation (MPEC) and Semi-Solid-State Fermentation (Semi-SSF), to increase the production of secondary metabolites during submerged fermentation. The addition of an inert support to the culture medium (Semi-SSF) resulted in a significant increase in the extract production. However, when talcum powder was added to different culture media, unexpected results were observed, with a decrease in the production of the biocompounds of interest. Metabolomic analyses showed that the production of aspergillic, neoaspergillic, and neohydroxyaspergillic acids peaked in the first few days of fermentation, with notable differences observed among the methodologies and culture media. Mellein production was particularly affected by the addition of an inert support to the culture medium. These results highlight the importance of surface properties and morphology of spores and mycelia during fermentation by this fungal species.

2.
Polymers (Basel) ; 15(17)2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37688207

RESUMO

In this study, a piezoelectric harvesting device was developed using polyvinylidene fluoride (PVDF) nanofibers reinforced with either BaTiO3 nanoparticles or graphene powder. BaTiO3 nanoparticles were synthesized through the sol-gel method with an average size of approximately 32 nm. The PVDF nanofibers, along with the nanoparticle composites in an acetone-N,N-dimethylformamide mixture, were produced using a centrifugal Forcespinning™ machine, resulting in a heterogeneous arrangement of fiber meshes, with an average diameter of 1.6 µm. Experimental tests revealed that the electrical performance of the fabricated harvester reached a maximum value of 35.8 Voc, demonstrating the potential of BaTiO3/ PVDF-based piezoelectric devices for designing wearable applications such as body-sensing and energy-harvesting devices.

3.
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1535906

RESUMO

Introduction: Tuberculosis is an infectious disease that can be prevented and cured, but it is still associated with high morbidity and mortality rates. Disseminated tuberculosis, although rare, can occur in individuals with underlying pathologies that affect the immune system. Currently, there are limited reports on disseminated tuberculosis in individuals with congenital disorders. Clinical case: We present a case of a patient with a history of ß thalassemia who was admitted to the emergency department with symptoms of abdominal pain and constitutional symptoms. The final diagnosis was disseminated tuberculosis. This case is of particular interest due to its atypical presentation, the initial suspicion of malignancy, and the extensive involvement of the disease despite the patient's absence of immunosuppression history. Conclusions: Disseminated tuberculosis in immunocompetent patients is a rare presentation associated with poor outcomes. The history of ß thalassemia may be a risk factor to consider based on the metabolic pathways involved in the pathophysiology of both diseases.


Introducción: la tuberculosis es una enfermedad infecciosa prevenible y curable asociada a una alta morbimortalidad, la presentación de tuberculosis diseminada es poco frecuente y está asociada a patologías que comprometen el sistema inmunitario. En la actualidad hay pocos informes sobre tuberculosis diseminada y trastornos congénitos subyacentes. Caso clínico: paciente con antecedente de talasemia ß que ingresó al servicio de urgencias por dolor abdominal y síntomas constitucionales con diagnóstico final de tuberculosis diseminada. Es un caso de especial interés debido a la presentación atípica, la sospecha diagnóstica inicial de malignidad y el amplio compromiso de la enfermedad a pesar de que el paciente no tenía antecedentes de inmunosupresión. Conclusiones: la tuberculosis diseminada en el paciente inmunocompetente es una presentación poco frecuente asociada a desenlaces adversos. El antecedente de talasemia ß podría ser un factor de riesgo para tener en cuenta con base en las vías metabólicas involucradas en la fisiopatología de ambas enfermedades.

4.
Nanomaterials (Basel) ; 12(19)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36234663

RESUMO

This article explores the industrial application of an Al-based nanocomposite reinforced with 0.5 wt.% of multiwalled carbon nanotubes with a Zn mechanical plating applied to fulfill the field requirements of electrical devices. The performance of electric devices made from this nanocomposite material and with a Zn plating was compared with that of MCCB devices using a normal Cu compound. MCCB devices with the Al-based nanocomposites compound showed a better performance, with less heat generated due to a flow of electrical charge passing through the device. The presence of MWCNTs in the Al nanocomposite dissipates heat, maintaining a stable electrical resistance in the MCCB, in contrast to what happens with Cu compound, which increases its electrical resistance as the temperature in the device increases.

5.
Front Cell Infect Microbiol ; 12: 809407, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35480235

RESUMO

Large-scale SARS-CoV-2 molecular testing coupled with whole genome sequencing in the diagnostic laboratories is instrumental for real-time genomic surveillance. The extensive genomic, laboratory, and clinical data provide a valuable resource for understanding cases of reinfection versus prolonged RNA shedding and protracted infections. In this study, data from a total of 22,292 clinical specimens, positive by SARS-CoV-2 molecular diagnosis at Johns Hopkins clinical virology laboratory between March 11th 2020 to September 23rd 2021, were used to identify patients with two or more positive results. A total of 3,650 samples collected from 1,529 patients who had between 2 and 20 positive results were identified in a time frame that extended up to 403 days from the first positive. Cycle threshold values (Ct) were available for 1,622 samples, the median of which was over 30 by 11 days after the first positive. Extended recovery of infectious virus on cell culture was notable for up to 70 days after the first positive in immunocompromised patients. Whole genome sequencing data generated as a part of our SARS-CoV-2 genomic surveillance was available for 1,027 samples from patients that had multiple positive tests. Positive samples collected more than 10 days after initial positive with high quality sequences (coverage >90% and mean depth >100), were more likely to be from unvaccinated, or immunosuppressed patients. Reinfections with viral variants of concern were found in 3 patients more than 130 days from prior infections with a different viral clade. In 75 patients that had 2 or more high quality sequences, the acquisition of more substitutions or deletions was associated with lack of vaccination and longer time between the recovered viruses. Our study highlights the value of integrating genomic, laboratory, and clinical data for understanding the biology of SARS-CoV-2 as well as for setting a precedent for future epidemics and pandemics.


Assuntos
COVID-19 , Reinfecção , COVID-19/diagnóstico , Genoma Viral/genética , Genômica , Humanos , Técnicas de Diagnóstico Molecular , RNA Viral/genética , SARS-CoV-2/genética
6.
Nanomaterials (Basel) ; 11(12)2021 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-34947721

RESUMO

The aim of this paper focuses on presenting a recent study that describes the fundamental steps needed to effectively scale-up from lab to mass production parts produced from Al powders reinforced with 0.5 wt% of industrial multiwalled carbon nanotubes (MWCNTs), with mechanical and electrical conductivity properties higher that those measured at the lab scale. The produced material samples were produced via a Spark Plasma Sintering (SPS) process using nanocomposite aluminum powders elaborated with a planetary ball-mill at the lab scale, and high-volume attrition milling equipment in combination with controlled atmosphere sinter hardening furnace equipment, which were used to consolidate the material at the industrial level. Surprisingly, the electrical conductivity and mechanical properties of the samples produced with the reinforced nanocomposite Al powders were made with mass production equipment and were similar or higher than those samples fabricated using metallic powders prepared with ball-mill lab equipment. Experimental measurements show that the hardness and the electrical conductivity properties of the samples fabricated with the mass production Al powders are 48% and 7.5% higher than those of the produced lab samples. This paper elucidates the steps that one needs to follow during the mass production process of reinforced aluminum powders to improve the physical properties of metallic samples consolidated via the SPS process.

7.
Nanomaterials (Basel) ; 11(5)2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33925115

RESUMO

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.

8.
Materials (Basel) ; 14(2)2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33466693

RESUMO

This paper focuses on reporting results obtained by the spark plasma sintering (SPS) consolidation and characterization of aluminum-based nanocomposites reinforced with concentrations of 0.5 wt%, 1 wt% and 2 wt% of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Experimental characterization performed by SEM shows uniform carbon nanotube (CNT) dispersion as well as carbon clusters located in the grain boundary of the Al matrix. The structural analysis and crystallite size calculation were performed by X-ray diffraction tests, detecting the characteristic CNT diffraction peak only for the composites reinforced with MWCNTs. Furthermore, a considerable increment in the crystallite size value for those Al samples reinforced and sintered with 1 wt% of CNTs was observed. Hardness tests show an improvement in the composite surface hardness of about 11% and 18% for those samples reinforced with 2 wt% of SWNCTs and MWCNTs, respectively. Conductivity measurements show that the Al samples reinforced with 2 wt% of MWCNTs and with 0.5 wt% SWCNTs reach the highest IACS values of 50% and 34%, respectively.

9.
Polymers (Basel) ; 11(12)2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31817694

RESUMO

This research focuses on developing a novel ultra high molecular weight polyethylene (UHMWPE) material reinforced with titanium dioxide (TiO 2 ) nanoparticles for producing craniofacial prostheses via an incremental sheet forming process (SPIF). First, UHMWPE-TiO 2 nanocomposite sheets were produced using incipient wetting and the compression molding process by considering different concentrations of TiO 2 nanoparticles. Then, the influence that the compression molding fabrication process has on the crystallinity and structural properties of the produced sample sheets was investigated. Experimental characterizations via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), tensile mechanical testing, and live/dead cell viability assays provided data that show an enhancement of the physical, mechanical, and biological properties. Finally, modifications on the nanocomposite material properties due to the SPIF manufacturing processes of a craniofacial prosthesis are addressed.

10.
Polymers (Basel) ; 11(12)2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31795142

RESUMO

This paper focuses on developing, fabricating, and characterizing composite polycaprolactone (PCL) membranes reinforced with titanium dioxide nanoparticles (NPs) elaborated by using two solvents; acetic acid and a mixture of chloroform and N,N-dimethylformamide (DMF). The resulting physical, chemical, and mechanical properties of the composite materials are studied by using experimental characterization techniques such as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-Ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, contact angle (CA), uniaxial and biaxial tensile tests, and surface roughness measurements. Experimental results show that the composite material synthesized by sol-gel and chloroform-DMF has a better performance than the one obtained by using acetic acid as a solvent.

11.
Acta colomb. psicol ; 22(1): 273-284, ene.-jun. 2019. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-989084

RESUMO

Resumen El presente estudio tuvo como objetivo adaptar la Escala de Sentido de Comunidad (SCI-II) a escuelas chilenas y analizar sus propiedades psicométricas. Se utilizó una muestra compuesta por 2871 estudiantes que cursaban entre 6. ° de enseñanza básica y 4. ° de enseñanza media de la comuna de Calama al norte de Chile. El 52.4 % (n = 1506) se identificó con el género femenino y la edad promedio de la muestra fue de 14.64 (DE = 2.046). Como resultados, el análisis factorial exploratorio indicó una solución de tres factores: conectividad escolar, pertenencia valorada y membresía-reciprocidad; la fiabilidad de la escala fue adecuada (α = .879 para conectividad escolar, α = .884 para pertenencia valorada y α = .716 para membresía reciprocidad); y los análisis confirmatorios indicaron índices de ajuste adecuados (CFI = .939; TLI = .933). Se concluye que el modelo propuesto de la versión adaptada es válido y es utilizable en futuros estudios sobre el sentido de comunidad en el contexto escolar. Al final se discute el valor de este instrumento para las políticas públicas y los procesos de innovación de la educación pública.


Resumo Este estudo teve como objetivo adaptar a Escala de Sentido de Comunidade (SCI-II) a escolas chilenas e analisar suas propriedades psicométricas. Participaram 2871 estudantes que cursavam entre o 6° do ensino básico e o 4° do ensino médio [nomenclatura usada no Chile] da comunidade de Calama, no norte do Chile. 52.4 % (n = 1506) foram identificados com o gênero feminino e idade média da amostra de 14.64 (DP = 2.046). A análise fatorial exploratória indicou uma solução de três fatores: conectividade escolar, pertencimento valorizado e filiação-reciprocidade. A confiabilidade da escala foi adequada (α = .879 para conectividade escolar, α = .884 para pertencimento valorizado e α = .716 para filiação-reciprocidade). As análises confirmatórias apresentaram índices de ajuste adequados (CFI = .939; TLI = .933). Conclui-se que o modelo proposto da versão adaptada é válido e é útil em futuros estudos sobre o sentido de comunidade no contexto escolar. Discute-se o valor desse instrumento para as políticas públicas para os processos de inovação da educação pública.


Abstract This study aimed to adapt the Sense of Community Index (SCI-II) in Chilean schools and to examine its psychometric properties. The validation process was conducted with 2871 students from 6th grade of elementary school to 4th grade of high school in a city of Northern Chile. A 52.4 % (n = 1506) of the sample identified with the female gender and the average age of the sample was 14.64 (SD = 2.046). An exploratory factor analysis indicated a three-factor solution: school connectivity, valued belongingness, and membership-reciprocity. The reliability of the scale was adequate (α = .879 for school connectivity, α = .884 for valued belongingness and α = .716 for membership-reciprocity), and confirmatory analyzes indicated adequate adjustment rates (CFI = .939; TLI = .933). It was concluded that the proposed model of the adapted version is valid and is appropriate to be used in future studies on the sense of community in the school context. Finally, the article discusses the value of this instrument for public policies and innovation processes of public education.


Assuntos
Humanos , Feminino , Criança , Adolescente , Testes Psicológicos , Relações Comunidade-Instituição , Ensino Fundamental e Médio
12.
Pediatr Infect Dis J ; 37(12): 1290-1293, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30408008

RESUMO

Zika virus is a mosquito-borne virus that causes congenital Zika syndrome, characterized by microcephaly and other fetal brain anomalies. This case report presents a case of Zika virus-related fetal brain anomalies including pathologic evidence of cerebral neuronal apoptosis and macrophage infiltrates and intracerebral calcification, ventriculomegaly and corpus callosum dysgenesis detected by ultrasound at 18 weeks of pregnancy.


Assuntos
Encéfalo/diagnóstico por imagem , Doenças do Sistema Nervoso/virologia , Ultrassonografia Pré-Natal/métodos , Infecção por Zika virus/diagnóstico por imagem , Adulto , Encéfalo/patologia , Feminino , Humanos , Doenças do Sistema Nervoso/diagnóstico por imagem , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico por imagem , Segundo Trimestre da Gravidez , Zika virus , Infecção por Zika virus/congênito
13.
Rev. colomb. reumatol ; 25(1): 38-54, Jan.-Mar. 2018. tab, graf
Artigo em Espanhol | LILACS | ID: biblio-960247

RESUMO

Resumen La activación de los linfocitos T se inicia a través de la presentación de antígenos endógenos o exógenos por células presentadoras de antígenos a través del complejo mayor de histocompatibilidad, el cual se une a un receptor especializado presente en los linfocitos T. Este reconocimiento desencadena una cascada de señalización intracelular que conlleva a un aumento en la expresión de integrinas, modificaciones del citoesqueleto y producción de factores de transcripción involucrados en la liberación de citocinas y mediadores inflamatorios. Uno de los inductores más importantes en la activación celular es el complejo enzimático con acción tirosina cinasa. Las cinasas que pertenecen a la familia SRC (SFK), FYN y LCK están involucradas en un gran número de procesos importantes en la activación, modulación de la respuesta linfocitaria y el desarrollo de enfermedades autoinmunes. La regulación de la señalización de las cinasas, así como de proteínas adaptadoras involucradas en la activación del linfocito T, son fundamentales para mantener el umbral de activación y modulación de la respuesta del linfocito. La fosforilación de sitios de regulación positiva de estas proteínas es importante para permitir una configuración activa de la proteína y de esta forma su máxima capacidad como cinasa. La fosforilación de los sitios de regulación negativa conlleva a una configuración cerrada de la proteína de tal forma que reduce su función de cinasa e inhibe su función. Las alteraciones en la señalización por modificación de algunas proteínas citoplasmáticas se asocian en algunos casos al desarrollo de enfermedades autoinmunes, como el lupus eritematoso sistémico. En condiciones fisiológicas, el complejo receptor de linfocitos T se reagrupa con complejos proteicos que interactúan armónicamente para generar una sen al interna. Los eventos de señalización alterados son en parte los responsables de una expresión anómala de citocinas, entre ellas la interleucina-6 (IL-6), IL-10, IL-2, IFN y CD40 ligando; estas modificaciones alteran la capacidad de los linfocitos T para sobre estimular a los linfocitos B, traduciéndose en un aumento en la producción de autoanticuerpos y en el desencadenamiento de la enfermedad autoinmune.


Abstract The activation of T cells is initiated by the presentation of exogenous or endogenous antigens, by antigen presenting cells through the major histocompatibility complex, which binds to a special receptor on T cells. This acknowledgement triggers a cascade of intracellular signalling that leads to an increase in integrin expression, cytoskeletal modifications, and transcription factors production involved in the liberation of cytokines and inflammatory mediators. One of the most important inducers in cell activation is the enzymatic complex with tyrosine kinase action. The kinases which belong to the SRC (SFK) LCK and FYN family have been involved in a large number of important processes in the activation and modulation of the T cells response, as well as in the development of autoimmune diseases. Regulating the kinases signalling, as well as the adapter proteins involved in T cell activation, is essential for maintaining an activation threshold, as well as the modulation of cell response. The phosphorylation of the positive regulation sites of these proteins is important to allow an active configuration of the protein and thereby its maximum capacity as kinase. The phosphorylation of negative regulation sites leads to a closed configuration of the protein that reduces its kinase function, and thereby inhibits its own function. The alteration in signalling by the modification of certain cytoplasmic proteins in some cases is associated with the development of autoimmune diseases, such as systemic lupus erythematosus. Under physiological conditions the T cell receptor complex regroups with protein complexes that interact harmonically to generate an internal signal. The altered signalling events are partly responsible for an anomalous expression of cytokines, including the interleukin-6 (IL-6), IL-10, IL-2, IFN, and CD40 linking, these modifications affects the cells ability to over-stimulate T and B cells, resulting in an increased production of autoantibodies and the triggering of the autoimmune disease.


Assuntos
Humanos , Linfócitos T , Lúpus Eritematoso Sistêmico , Citocinas , Histocompatibilidade , Antígenos
14.
Am J Obstet Gynecol ; 218(4): 440.e1-440.e36, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29353032

RESUMO

BACKGROUND: Congenital Zika virus (ZIKV) infection can be detected in both the presence and absence of microcephaly and manifests as a number of signs and symptoms that are detected clinically and by neuroimaging. However, to date, qualitative and quantitative measures for the purpose of diagnosis and prognosis are limited. OBJECTIVES: Main objectives of this study conducted on fetuses and infants with confirmed congenital Zika virus infection and detected brain abnormalities were (1) to assess the prevalence of microcephaly and the frequency of the anomalies that include a detailed description based on ultrasound and magnetic resonance imaging in fetuses and ultrasound, magnetic resonance imaging, and computed tomography imaging postnatally, (2) to provide quantitative measures of fetal and infant brain findings by magnetic resonance imaging with the use of volumetric analyses and diffusion-weighted imaging, and (3) to obtain additional information from placental and fetal histopathologic assessments and postnatal clinical evaluations. STUDY DESIGN: This is a longitudinal cohort study of Zika virus-infected pregnancies from a single institution in Colombia. Clinical and imaging findings of patients with laboratory-confirmed Zika virus infection and fetal brain anomalies were the focus of this study. Patients underwent monthly fetal ultrasound scans, neurosonography, and a fetal magnetic resonance imaging. Postnatally, infant brain assessment was offered by the use of ultrasound imaging, magnetic resonance imaging, and/or computed tomography. Fetal head circumference measurements were compared with different reference ranges with <2 or <3 standard deviations below the mean for the diagnosis of microcephaly. Fetal and infant magnetic resonance imaging images were processed to obtain a quantitative brain volumetric assessment. Diffusion weighted imaging sequences were processed to assess brain microstructure. Anthropometric, neurologic, auditory, and visual assessments were performed postnatally. Histopathologic assessment was included if patients opted for pregnancy termination. RESULTS: All women (n=214) had been referred for Zika virus symptoms during pregnancy that affected themselves or their partners or if fetal anomalies that are compatible with congenital Zika virus syndrome were detected. A total of 12 pregnant patients with laboratory confirmation of Zika virus infection were diagnosed with fetal brain malformations. Most common findings that were assessed by prenatal and postnatal imaging were brain volume loss (92%), calcifications (92%), callosal anomalies (100%), cortical malformations (89%), and ventriculomegaly (92%). Results from fetal brain volumetric assessment by magnetic resonance imaging showed that 1 of the most common findings associated with microcephaly was reduced supratentorial brain parenchyma and increased subarachnoid cerebrospinal fluid. Diffusion weighted imaging analyses of apparent diffusion coefficient values showed microstructural changes. Microcephaly was present in 33.3-58.3% of the cases at referral and was present at delivery in 55.6-77.8% of cases. At birth, most of the affected neonates (55.6-77.8%) had head circumference measurements >3 standard deviations below the mean. Postnatal imaging studies confirmed brain malformations that were detected prenatally. Auditory screening results were normal in 2 cases that were assessed. Visual screening showed different anomalies in 2 of the 3 cases that were examined. Pathologic results that were obtained from 2 of the 3 cases who opted for termination showed similar signs of abnormalities in the central nervous system and placental analyses, including brain microcalcifications. CONCLUSION: Congenital microcephaly is not an optimal screening method for congenital Zika virus syndrome, because it may not accompany other evident and preceding brain findings; microcephaly could be an endpoint of the disease that results from progressive changes that are related to brain volume loss. Long-term studies are needed to understand the clinical and developmental relevance of these findings.


Assuntos
Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Complicações Infecciosas na Gravidez/epidemiologia , Infecção por Zika virus/epidemiologia , Adolescente , Adulto , Calcinose/diagnóstico por imagem , Líquido Cefalorraquidiano/fisiologia , Estudos de Coortes , Colômbia/epidemiologia , Diagnóstico por Imagem , Potenciais Evocados Auditivos , Potenciais Evocados Visuais , Feminino , Humanos , Hidrocefalia/diagnóstico por imagem , Recém-Nascido , Estudos Longitudinais , Microcefalia/virologia , Gravidez , Espaço Subaracnóideo/fisiologia , Adulto Jovem , Infecção por Zika virus/congênito
15.
J Environ Manage ; 206: 60-64, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-29059571

RESUMO

1,4-Dioxane (dioxane) is a groundwater contaminant of emerging concern for which bioremediation may become a practical remediation strategy. Therefore, it is important to advance our heuristic understanding of geochemical parameters that are most influential on the potential success of intrinsic bioremediation of dioxane-impacted sites. Here, Pearson's and Spearman's correlation and linear regression analyses were conducted to discern associations between 1,4-dioxane biodegradation activity measured in aerobic microcosms and groundwater geochemical parameters at four different contaminated sites. Dissolved oxygen, which is known to limit dioxane biodegradation, was excluded as a limiting factor in this analysis. Biodegradation activity was positively associated with dioxane concentrations (p < 0.01; R < 0.70) as well as the number of catabolic thmA gene copies (p < 0.01; R = 0.80) encoding dioxane monooxygenase. Thus, whereas environmental factors such as pH, temperature, and nutrients may influence dioxane biodegradation, these parameters did not exert as strong of an influence on potential biodegradation activity as the in situ concentration of substrate dioxane at the time of sampling. This analysis infers that aerobic sites with higher dioxane concentrations are more likely to select and sustain a thriving population of dioxane degraders, while sites with relatively low dioxane concentrations would be more difficult to attenuate naturally and may require alternative remediation strategies.


Assuntos
Biodegradação Ambiental , Dioxanos , Poluentes Químicos da Água , Água Subterrânea
16.
BMC Genomics ; 14: 565, 2013 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-23957733

RESUMO

BACKGROUND: Lymphocytes achieve diversity in antigen recognition in part by rearranging genomic DNA at loci encoding antibodies and cell surface receptors. The process, termed V(D)J recombination, juxtaposes modular coding sequences for antigen binding. Erroneous recombination events causing chromosomal translocations are recognized causes of lymphoid malignancies. Here we show a hybridization based method for sequence enrichment can be used to efficiently and selectively capture genomic DNA adjacent to V(D)J recombination breakpoints for massively parallel sequencing. The approach obviates the need for PCR amplification of recombined sequences. RESULTS: Using tailored informatics analyses to resolve alignment and assembly issues in these repetitive regions, we were able to detect numerous recombination events across a panel of cancer cell lines and primary lymphoid tumors, and an EBV transformed lymphoblast line. With reassembly, breakpoints could be defined to single base pair resolution. The observed events consist of canonical V(D)J or V-J rearrangements, non-canonical rearrangements, and putatively oncogenic reciprocal chromosome translocations. We validated non-canonical and chromosome translocation junctions by PCR and Sanger sequencing. The translocations involved the MYC and BCL-2 loci, and activation of these was consistent with histopathologic features of the respective B-cell tumors. We also show an impressive prevalence of novel erroneous V-V recombination events at sites not incorporated with other downstream coding segments. CONCLUSIONS: Our results demonstrate the ability of next generation sequencing to describe human V(D)J recombinase activity and provide a scalable means to chronicle off-target, unexpressed, and non-amplifiable recombinations occurring in the development of lymphoid cancers.


Assuntos
Rearranjo Gênico , Leucemia Linfoide/genética , VDJ Recombinases/fisiologia , Linfócitos B/enzimologia , Sequência de Bases , Carcinogênese/genética , Linhagem Celular Tumoral , Pontos de Quebra do Cromossomo , Mapeamento Cromossômico , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Leucemia Linfoide/enzimologia , Análise de Sequência de DNA , Translocação Genética
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