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1.
J Allergy Clin Immunol ; 151(4): 1081-1095, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36228738

RESUMO

BACKGROUND: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. OBJECTIVE: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. METHODS: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. RESULTS: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. CONCLUSION: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.


Assuntos
Doenças do Sistema Imunitário , Síndromes de Imunodeficiência , Criança , Humanos , Autoimunidade/genética , Estudos de Coortes , Mutação com Ganho de Função , Síndromes de Imunodeficiência/genética , Mutação , Fator de Transcrição STAT3/genética , Proliferação de Células , Linfócitos
2.
Environ Microbiol ; 25(1): 161-166, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36263658

RESUMO

An efficient and cheap energization of microbial biocatalysts is essential in current biotechnological processes. A promising alternative to the use of common organic or inorganic electron donors is the semiconductor nanoparticles (SNs) that absorb light and transfer electrons (photoelectrons) behaving as artificial photosynthetic systems (biohybrid systems). Excited photoelectrons generated by illuminated SNs are highly reductive and readily accepted by membrane-bound proteins and electron shuttles to drive specific cell reduction processes and energy generation in microbes. However, the operational mechanisms of these hybrid systems are still poorly understood, especially at the material-microbe interface, and therefore the design and production of efficient biohybrids are challenging. Some major limitations/challenges and future prospects of SNs as microbial energization systems are discussed.


Assuntos
Fotossíntese
3.
Pediatr Dev Pathol ; 26(4): 362-373, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37165556

RESUMO

BACKGROUND: Pathologic characterization of pulmonary complications following hematopoietic stem cell transplantation (HSCT) is limited. We describe lung findings in pediatric patients who died following HSCT and attempt to identify potential clinical associations. METHODS: Pathology databases at Texas Children's Hospital and the Children's Hospital of Philadelphia were queried (2013-2018 CHOP and 2017-2018 TCH). Electronic medical records and slides were reviewed. RESULTS: Among 29 patients, 19 received HSCT for hematologic malignancy, 8 for non-malignant hematologic disorders, and 2 for metastatic solid tumors. Twenty-five patients (86%) showed 1 or more patterns of acute and organizing lung injury. Sixty-two percent had microvascular sclerosis, with venous involvement noted in most cases and not correlating with clinical history of pulmonary hypertension, clinical transplant-associated thrombotic microangiopathy, irradiation, or graft-versus-host disease. Features suggestive of graft-versus-host-disease were uncommon: 6 patients had lymphocytic bronchiolitis, and only 2 patients had evidence of bronchiolitis obliterans (both clinically unexpected), both with a mismatched unrelated donor transplant. CONCLUSIONS: Acute and subacute alveolar injury (diffuse alveolar damage or organizing pneumonia) is common in pediatric patients who died following HSCT and is difficult to assign to a specific etiology. Microvascular sclerosis was frequent and did not correlate with a single distinct clinical feature.

4.
Food Microbiol ; 110: 104185, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36462831

RESUMO

The aim of the present work was the selection of aromatic plant essential oils (EOs) and/or ethanolic extracts (EEs) to prevent the late blowing defect (LBD) of cheese caused by Clostridium spp. EEs resulted more effective than EOs to inhibit dairy-borne Clostridium spp. in vitro. Savory, hyssop, lavender and tarragon EEs, which showed the lowest minimal inhibitory concentration against Clostridium tyrobutyricum, were selected to study the prevention of LBD caused by this bacterium in cheese. Addition of savory and lavender EEs to cheese milk delayed LBD by 2 weeks, but at the end of ripening these cheeses showed similar clostridial vegetative cells counts, spoilage symptoms and propionic, and butyric acids levels than blown control cheese. Tarragon EE, with the highest content in caffeic acid, also delayed LBD by 2 weeks, but it was more effective to inhibit Clostridium, since cheese with tarragon EE showed minor LBD symptoms, lower vegetative cells count and lower concentrations of propionic and butyric acids than the rest of cheeses made with EEs. This fact could be also attributable to the greater number of antimicrobial terpenes (1,8-cineole, 4-terpineol, α-terpineol, isoelemicin, methyl eugenol, and methyl trans-isoeugenol) detected in this cheese. This is the first report on the application of EEs to control C. tyrobutyricum in cheese.


Assuntos
Queijo , Clostridium tyrobutyricum , Óleos Voláteis , Clostridium , Etanol , Óleos Voláteis/farmacologia , Óleos de Plantas , Butiratos , Extratos Vegetais/farmacologia
5.
Pediatr Radiol ; 53(5): 844-853, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36746811

RESUMO

BACKGROUND: Autosomal dominant mutations in the coatomer-associated protein alpha (COPA) gene cause an immune dysregulation disorder associated with pulmonary hemorrhage, lymphoid hyperplasia, arthritis, and glomerulonephritis. OBJECTIVE: To describe the thoracic, musculoskeletal, and renal imaging findings of COPA syndrome with a focus on the evolution of the pulmonary findings. MATERIALS AND METHODS: With approval of the Institutional Review Board, consensus retrospective review of findings on chest radiography and computed tomography (CT), musculoskeletal radiography and magnetic resonance imaging (MRI), and renal ultrasound (US) was performed for pediatric COPA syndrome patients. COPA syndrome patients < 18 years of age presenting between 1992 and 2019 were identified from an institutional rheumatology registry. RESULTS: Twelve pediatric COPA syndrome patients (mean age of 6.5 years at first imaging exam; 6 females) were identified. Imaging exams available for review included 45 chest CT exams on 12 patients, 37 musculoskeletal exams on 4 patients, and 10 renal US exams on 5 patients. All 12 had abnormal chest CT exams, with findings including ground-glass opacities (12/12), cysts (8/12), septal thickening (9/12), nodules (8/12), fibrosis (7/12), crazy-paving (2/12), consolidation (1/12), hilar/mediastinal lymphadenopathy (11/12), and chest wall deformity (5/12). Nine had at least one follow-up chest CT, which showed improvement in nodules (7/9), ground-glass opacities (4/9), and lymphadenopathy (9/9), but worsening of septal thickening (3/9), cyst formation (3/9), and fibrosis (3/9). Four had musculoskeletal imaging revealing synovitis (2/4), bone erosions (1/4), tenosynovitis (1/4), enthesitis (1/4), and subcutaneous nodules (1/4). Five had at least one renal US, revealing renal size abnormalities (4/5) and cortical hyperechogenicity (3/5). CONCLUSION: The most prevalent imaging finding of COPA syndrome is diffuse lung disease related to early childhood-onset recurrent pulmonary hemorrhage and lymphoid hyperplasia that may progress to pulmonary fibrosis. Other imaging findings manifesting later in childhood or adolescence relate to arthritis and glomerulonephritis.


Assuntos
Artrite , Glomerulonefrite , Nefropatias , Pneumopatias , Linfadenopatia , Criança , Feminino , Humanos , Artrite/genética , Proteína Coatomer/genética , Fibrose , Hemorragia , Hiperplasia , Pulmão , Pneumopatias/diagnóstico por imagem , Pneumopatias/genética , Estudos Retrospectivos , Síndrome , Masculino
6.
Pediatr Radiol ; 52(10): 2029-2037, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35699763

RESUMO

As the number of childhood cancer survivors increases, a heightened awareness and recognition of therapy-related late effects is becoming more important. Pulmonary complications are the third leading cause of late mortality in cancer survivors. Diagnosis of these complications on chest imaging helps facilitate prompt treatment to mitigate adverse outcomes. In this review, we summarize the imaging of late pulmonary complications of cancer therapy in children and highlight characteristic findings that should be recognized by radiologists.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Neoplasias , Criança , Diagnóstico por Imagem , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Neoplasias/complicações , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Sobreviventes
7.
Sensors (Basel) ; 22(6)2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35336255

RESUMO

Rollators are widely used in clinical rehabilitation for gait assessment, but gait analysis usually requires a great deal of expertise and focus from medical staff. Smart rollators can capture gait parameters autonomously while avoiding complex setups. However, commercial smart rollators, as closed systems, can not be modified; plus, they are often expensive and not widely available. This work presents a low cost open-source modular rollator for monitorization of gait parameters and support. The whole system is based on commercial components and its software architecture runs over ROS2 to allow further customization and expansion. This paper describes the overall software and hardware architecture and, as an example of extended capabilities, modules for monitoring dynamic partial weight bearing and for estimation of spatiotemporal gait parameters of clinical interest. All presented tests are coherent from a clinical point of view and consistent with input data.


Assuntos
Marcha , Caminhada , Análise da Marcha , Humanos , Monitorização Fisiológica , Software
8.
Rheumatology (Oxford) ; 60(7): 3199-3208, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33355338

RESUMO

OBJECTIVES: ANCA-associated vasculitis (AAV) usually involves the renal and respiratory systems, but the paediatric literature on pulmonary manifestations and outcomes is limited. We aimed to describe pulmonary manifestations and outcomes after therapy in a cohort of paediatric AAV (pAAV) patients. METHODS: A retrospective chart review of all patients <19 years presenting to our institution with AAV between 1/2008 and 2/2018 was conducted. Patient demographics, clinical presentation, diagnostic testing, therapy and pulmonary outcomes over the first 3 years after presentation were evaluated. RESULTS: A total of 38 patients were included; all had ANCA positivity by immunofluorescence. A total of 23 had microscopic polyangiitis (MPA), 13 had granulomatosis with polyangiitis and 2 had eosinophilic granulomatosis with polyangiitis. A total of 30 (79%) had pulmonary manifestations, with cough (73%) and pulmonary haemorrhage (67%) being the most common. Abnormalities were noted in 82% of chest CT scans reviewed, with nodules and ground-glass opacities being the most common. At 6, 12 and 36 months follow-up, respectively, 61.8%, 39.4% and 29% of patients continued to show pulmonary manifestations. Five MPA patients with re-haemorrhage are described in detail. CONCLUSION: MPA was more common than granulomatosis with polyangiitis, with pulmonary involvement being common in both. MPA patients had more severe pulmonary manifestations. Chest CT revealed abnormal findings in a majority of cases. A subgroup of young MPA patients experienced repeat pulmonary haemorrhage. Treatment modality and response were comparable in different subtypes of AAV, except for this young MPA group. Additional prospective studies are needed to better understand the different phenotypes of pAAV.


Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/fisiopatologia , Tosse/fisiopatologia , Hemoptise/fisiopatologia , Hemorragia/fisiopatologia , Pneumopatias/fisiopatologia , Nódulos Pulmonares Múltiplos/fisiopatologia , Adolescente , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/imunologia , Autoanticorpos/imunologia , Criança , Pré-Escolar , Síndrome de Churg-Strauss/imunologia , Síndrome de Churg-Strauss/fisiopatologia , Estudos de Coortes , Progressão da Doença , Feminino , Granulomatose com Poliangiite/imunologia , Granulomatose com Poliangiite/fisiopatologia , Hemoptise/imunologia , Hemorragia/imunologia , Humanos , Lactente , Pneumopatias/diagnóstico por imagem , Pneumopatias/imunologia , Masculino , Poliangiite Microscópica/imunologia , Poliangiite Microscópica/fisiopatologia , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Mieloblastina/imunologia , Peroxidase/imunologia , Recidiva , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
9.
Pediatr Dev Pathol ; 24(3): 227-234, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33651637

RESUMO

INTRODUCTION AND AIM: Multiorgan autoimmunity and interstitial lung disease (ILD) are reported in patients with STAT3 GOF syndrome. RESULTS: We present lung histopathology findings in 3 such children, two of whom underwent wedge biopsies with adequate diagnostic material. Wedge biopsies showed interstitial cellular expansion with linear and nodular aggregates of CD8 positive T lymphocytes, plasma cells, and histiocytes; consistent with lymphocytic interstitial pneumonia pattern (LIP). CD4+ T cells and CD20+ B cells were present but infrequent in the interstitium. FOXP3 cells ranged from 0-5%. Focal interstitial and intraalveolar histiocytes were also seen. Neutrophils and eosinophils were rare/absent. Non-occlusive peribronchial lymphoid aggregates showed equal T and B cells; likely reactive in nature. Pulmonary vessels appeared normal without vasculitis or hypertensive change. There was no interstitial or subepithelial fibrosis or organizing pneumonia. Interlobular septa and visceral pleura were unremarkable. CONCLUSION: Children with multi-system autoimmune disorders with ILD should be investigated for STAT3 GOF syndrome. Lung wedge biopsies are more informative than transbronchial biopsies, if a tissue sampling is indicated. CD8 dominant T cell inflammation seems to be a key driver of ILD. Although interstitial fibrosis was not seen in our small sample, longer follow up is needed to understand the natural history.


Assuntos
Doenças Autoimunes/genética , Doenças Pulmonares Intersticiais/patologia , Pulmão/patologia , Fator de Transcrição STAT3/genética , Pré-Escolar , Feminino , Mutação com Ganho de Função , Humanos , Lactente , Recém-Nascido , Doenças Pulmonares Intersticiais/genética , Masculino
10.
Molecules ; 26(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33401499

RESUMO

Guayule (Parthenium argentatum Gray) is a promising alternative source to Hevea brasiliensis for the production of natural rubber, which can reach levels of 8-9% under industrialized farming conditions. The most common method for determining rubber concentration is by accelerated solvent extraction (ASE), a technique developed by the Dionex Corporation and almost exclusively performed with the Dionex ASE-200 or 350 systems. Herein, it is sought to apply and adapt the most common methods used in the literature for the Dionex system to another extraction platform, the BÜCHI Speed Extractor E-914. Results showed that using a sand sandwich method to confine the sample in the center and exploiting a larger cell volume (80 mL) for extraction prevents the occurrence of overpressure and problems with clogging. Under optimized conditions, the coefficient of variation was <15% for both resin quantification for samples containing 5.0-15.8% of resin and for rubber quantification for samples with 1.7-10.3% rubber content. The extraction time for resin (2 cycles of 5 min each) was smaller than for rubber (2 cycles of 20 min each). It would be interesting to carry out interlaboratory comparisons to standardize the method at an international level.


Assuntos
Asteraceae/química , Resinas Vegetais , Borracha , Resinas Vegetais/química , Resinas Vegetais/isolamento & purificação , Borracha/química , Borracha/isolamento & purificação , Solventes/química
11.
J Orthop Traumatol ; 22(1): 38, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34559320

RESUMO

BACKGROUND: There is still little information about the long-term results of clinical and radiological evolution in patients older than 65 years with complex proximal humerus fractures (CPHF) treated acutely with reverse shoulder arthroplasty (RSA). The aim of this paper was to evaluate function and results 7 years after surgery. MATERIAL AND METHODS: A prospective cross-sectional cohort study was designed for this purpose. Patients who underwent RSA surgery during 2012 because of a CPHF were included. The surgical approach was randomized (deltopectoral vs anterosuperior). Functional activity, evolution of tuberosities and evidence of scapular notching 7 years after surgery were analyzed. RESULTS: After evaluating 32 patients, the Constant score improved from 64.83 in the first year to 69.54 at 7 years postoperative. Results were independent of the approach used. Functional outcomes were poorer in patients with scapular notching and when tuberosities were resorbed or displaced. CONCLUSIONS: At 7 years, function in patients undergoing RSA after CPHF demonstrated improvement in all patients except those who developed scapular notching or when tuberosities did not consolidate in an anatomical position. These results are completely independent of the approach used. LEVEL OF EVIDENCE: III Controlled cohort study.


Assuntos
Artroplastia do Ombro , Fraturas do Ombro , Articulação do Ombro , Idoso , Estudos de Coortes , Estudos Transversais , Seguimentos , Humanos , Úmero , Estudos Prospectivos , Estudos Retrospectivos , Fraturas do Ombro/diagnóstico por imagem , Fraturas do Ombro/cirurgia , Articulação do Ombro/diagnóstico por imagem , Articulação do Ombro/cirurgia , Resultado do Tratamento
12.
Nature ; 515(7528): 568-71, 2014 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-25428505

RESUMO

Therapies that target the programmed death-1 (PD-1) receptor have shown unprecedented rates of durable clinical responses in patients with various cancer types. One mechanism by which cancer tissues limit the host immune response is via upregulation of PD-1 ligand (PD-L1) and its ligation to PD-1 on antigen-specific CD8(+) T cells (termed adaptive immune resistance). Here we show that pre-existing CD8(+) T cells distinctly located at the invasive tumour margin are associated with expression of the PD-1/PD-L1 immune inhibitory axis and may predict response to therapy. We analysed samples from 46 patients with metastatic melanoma obtained before and during anti-PD-1 therapy (pembrolizumab) using quantitative immunohistochemistry, quantitative multiplex immunofluorescence, and next-generation sequencing for T-cell antigen receptors (TCRs). In serially sampled tumours, patients responding to treatment showed proliferation of intratumoral CD8(+) T cells that directly correlated with radiographic reduction in tumour size. Pre-treatment samples obtained from responding patients showed higher numbers of CD8-, PD-1- and PD-L1-expressing cells at the invasive tumour margin and inside tumours, with close proximity between PD-1 and PD-L1, and a more clonal TCR repertoire. Using multivariate analysis, we established a predictive model based on CD8 expression at the invasive margin and validated the model in an independent cohort of 15 patients. Our findings indicate that tumour regression after therapeutic PD-1 blockade requires pre-existing CD8(+) T cells that are negatively regulated by PD-1/PD-L1-mediated adaptive immune resistance.


Assuntos
Imunidade Adaptativa/imunologia , Linfócitos T CD8-Positivos/imunologia , Imunoterapia , Melanoma/terapia , Modelos Biológicos , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Linfócitos T CD8-Positivos/citologia , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Melanoma/diagnóstico , Melanoma/imunologia , Melanoma/patologia , Pessoa de Meia-Idade , Análise Multivariada , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Resultado do Tratamento
13.
J Food Sci Technol ; 55(3): 1093-1103, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29487452

RESUMO

A new aromatization method for olive oils with saffron aqueous extracts rich in safranal has been developed using liquid-liquid extraction. Four flavoured olive oils were obtained (SO1-SO4). SO1 showed the highest safranal concentration (145.89 mg L-1), followed by SO2 (79.33 mg L-1), SO3 (0.30 mg L-1) and SO4 (0.01 mg L-1). Although flavouring originated a decrease in the quality parameters and the oxidative stability of the oils, even after 7 months of storage, at room and refrigeration temperatures, the oil parameters evaluated were still comparable to those of extra virgin olive oil. Flavored olive oils with less safranal (SO3, SO4) are preferred by consumers.

14.
J Environ Manage ; 186(Pt 2): 207-213, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27140327

RESUMO

Contamination by atmospheric mercury has been assessed in two different areas from Spain (Las Cuevas, Ciudad Real and Flix, Tarragona) using lichens as biomonitors. The relationship established between mercury contents in the soils and the gaseous mercury (GM) was also observed. It was found that the GM is highest in the vicinity of the source and it is dispersed depending on of the distance to the source and the wind directions. The mercury concentration in the gas phase in Flix was higher than that found in Las Cuevas and also higher than the value that the US EPA recommended. The mercury bioaccumulation in the native lichens from genders Ramalina and Xanthoria were used as biomonitors for absorbing mercury in Las Cuevas and Flix, respectively. The mercury uptake by Ramalina was higher than the amount accumulated by Xanthoria, a difference that was mainly due to the lichen characteristics. The content of mercury in lichens in relation to the mercury in gas was fitted by a Freundlich type equation, indicating that the equilibrium between both phases was established. Besides, transplanted Ramalina lichen in Las Cuevas allowed to obtain the kinetic of mercury uptake. A kinetic model of first order based on the equilibrium was proposed and the mass transfer constants for each sampling station were estimated. As it was expected, these values increased with the predominant wind flow direction.


Assuntos
Monitoramento Ambiental/métodos , Líquens/fisiologia , Mercúrio/análise , Poluentes do Solo/análise , Gases , Mercúrio/farmacocinética , Modelos Teóricos , Solo/química , Poluentes do Solo/farmacocinética , Espanha , Vento
15.
J Biol Chem ; 290(19): 12165-83, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-25795774

RESUMO

The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the ß-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB 1, and P3 R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds.


Assuntos
Azoarcus/metabolismo , Proteínas de Bactérias/química , Benzoatos/química , Regulação Bacteriana da Expressão Gênica , Proteínas Repressoras/química , Sequência de Aminoácidos , Anaerobiose , Cristalografia por Raios X , DNA/química , Desoxirribonuclease I/química , Perfilação da Expressão Gênica , Óperon Lac , Modelos Moleculares , Dados de Sequência Molecular , Família Multigênica , Mutação , Oligonucleotídeos/química , Plasmídeos/metabolismo , Regiões Promotoras Genéticas , Conformação Proteica , Homologia de Sequência de Aminoácidos , Transcrição Gênica , Ultracentrifugação , beta-Galactosidase/metabolismo
16.
Microb Cell Fact ; 15(1): 109, 2016 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-27301452

RESUMO

BACKGROUND: Different bacteria have been reported so far that link selenite resistance to the production of metallic selenium nanoparticles (SeNPs). Although SeNPs have many biotechnological applications in diverse areas, the molecular mechanisms involved in their microbial genesis are not fully understood. The Azoarcus genus is a physiologically versatile group of beta-proteobacteria of great environmental relevance. Azoarcus sp. CIB is a facultative anaerobe that combines the ability to degrade under aerobic and/or anaerobic conditions a wide range of aromatic compounds, including some toxic hydrocarbons such as toluene and m-xylene, with an endophytic life style in the root of rice. We unravel here an additional physiological feature of the strain CIB that is related to its resistance to selenium oxyanions and the formation of SeNPs. RESULTS: This work is the first report of a member of the Azoarcus genus that is able to anaerobically grow in the presence of selenite. Electron microscopy preparations and X-ray spectroscopy analyses demonstrate the reduction of selenite to spherical electron-dense SeNPs whose average size was 123 ± 35 nm of diameter. Our data suggest that the main molecular mechanism of selenite resistance resides on an energy-dependent selenite exporter. Azoarcus cells trigger the synthesis of SeNPs when they reach the stationary-phase of growth, and either the exhaustion of electron donor or acceptor, both of which lead to starvation conditions, produce the reduction of selenite to red elemental selenium. Azoarcus becomes a promising biocatalyst, either as whole cells or cellular extracts, for the anaerobic and/or aerobic green synthesis of SeNPs. CONCLUSIONS: Azoarcus turns out to be a new eco-friendly system to reduce selenite and produce spherical SeNPs. Moreover, this is the first report of a rice endophyte able to produce SeNPs. Since Azoarcus is also able to degrade both aerobically and anaerobically toxic aromatic compounds of great environmental concern, it becomes a suitable candidate for a more sustainable agricultural practice and for bioremediation strategies.


Assuntos
Azoarcus/metabolismo , Nanopartículas Metálicas/química , Selênio/metabolismo , Azoarcus/química , Tamanho da Partícula , Ácido Selenioso/metabolismo , Selênio/química
19.
J Biol Chem ; 289(4): 1892-904, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24302740

RESUMO

Here we characterized the first known transcriptional regulator that accounts for carbon catabolite repression (CCR) control of the anaerobic catabolism of aromatic compounds in bacteria. The AccR response regulator of Azoarcus sp. CIB controls succinate-responsive CCR of the central pathways for the anaerobic catabolism of aromatics by this strain. Phosphorylation of AccR to AccR-P triggers a monomer-to-dimer transition as well as the ability to bind to the target promoter and causes repression both in vivo and in vitro. Substitution of the Asp(60) phosphorylation target residue of the N-terminal receiver motif of AccR to a phosphomimic Glu residue generates a constitutively active derivative that behaves as a superrepressor of the target genes. AccR-P binds in vitro to a conserved inverted repeat (ATGCA-N6-TGCAT) present at two different locations within the PN promoter of the bzd genes for anaerobic benzoate degradation. Because the DNA binding-proficient C-terminal domain of AccR is monomeric, we propose an activation mechanism in which phosphorylation of Asp(60) of AccR alleviates interdomain repression mediated by the N-terminal domain. The presence of AccR-like proteins encoded in the genomes of other ß-proteobacteria of the Azoarcus/Thauera group further suggests that AccR constitutes a master regulator that controls anaerobic CCR in these bacteria.


Assuntos
Azoarcus/metabolismo , Proteínas de Bactérias/metabolismo , Benzoatos/metabolismo , Repressão Catabólica/fisiologia , Elementos de Resposta/fisiologia , Fatores de Transcrição/metabolismo , Substituição de Aminoácidos , Anaerobiose/fisiologia , Azoarcus/genética , Proteínas de Bactérias/genética , Mutação de Sentido Incorreto , Fatores de Transcrição/genética
20.
J Microencapsul ; 32(7): 642-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26299426

RESUMO

Mercury is one of the most toxic pollutants, with high capacity of accumulation in living organism, causing important human health problems. Therefore, the mercury removal from water is an important research goal. In a previous work, an extractant agent [di(2-ethylhexyl)phosphoric acid] was microencapsulated in poly(styrene-co-divinylbenzene) by means of suspension polymerisation using toluene as diluent. In this study, this recipe has been modified changing the toluene by heptane and extended to four additional extractants (trioctylamine, trioctylmethylammonium chloride [TOMAC], tributyl phosphate and trioctylphosphine oxide). The polluting potential of the waste liquid from the process was measured by total organic carbon and chemical oxygen demand analyses. The morphology, particle size and distribution were studied by scanning electron microscopy and low angle laser light scattering. The amount of extractant agent into the microcapsules and the microencapsulation efficiency were determined by thermogravimetric analysis and the mercury removal capacity by equilibrium studies. Microcapsules containing TOMAC demonstrated to be the best material for the mercury removal and retention.


Assuntos
Cápsulas/síntese química , Mercúrio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Análise da Demanda Biológica de Oxigênio , Carbono/análise , Composição de Medicamentos , Organofosfatos , Tamanho da Partícula , Poliestirenos , Solventes , Termogravimetria
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