Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 51
Filtrar
1.
Biotechnol Biofuels Bioprod ; 17(1): 51, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38566218

RESUMO

BACKGROUND: Petrochemicals contribute to environmental issues, with concerns ranging from energy consumption and carbon emission to pollution. In contrast, microbial biorefineries offer eco-friendly alternatives. The solvent-tolerant Pseudomonas putida DOT-T1E serves as a suitable host for producing aromatic compounds, specifically L-phenylalanine and its derivative, 2-phenylethanol (2-PE), which find widespread applications in various industries. RESULTS: This study focuses on enhancing 2-PE production in two L-phenylalanine overproducing strains of DOT-T1E, namely CM12-5 and CM12-5Δgcd (xylABE), which grow with glucose and glucose-xylose, respectively. To synthesize 2-PE from L-phenylalanine, these strains were transformed with plasmid pPE-1, bearing the Ehrlich pathway genes, and it was found higher 2-PE production with glucose (about 50-60 ppm) than with xylose (< 3 ppm). To understand the limiting factors, we tested the addition of phenylalanine and intermediates from the Ehrlich and shikimate pathways. The results identified intracellular L-phenylalanine as a key limiting factor for 2-PE production. To overcame this limitation, a chorismate mutase/prephenate dehydratase variant-insentive to feedback inhibition by aromatic amino acids-was introduced in the producing strains. This led to increased L-phenylalanine production and subsequently produced more 2-PE (100 ppm). Random mutagenesis of the strains also produced strains with higher L-phenylalanine titers and increased 2-PE production (up to 120 ppm). The improvements resulted from preventing dead-end product accumulation from shikimate and limiting the catabolism of potential pathway intermediates in the Ehrlich pathway. The study explored agricultural waste substrates, such as corn stover, sugarcane straw and corn-syrup as potential C sources. The best results were obtained using 2G substrates at 3% (between 82 and 100 ppm 2-PE), with glucose being the preferred sugar for 2-PE production among the monomeric sugars in these substrates. CONCLUSIONS: The findings of this study offer strategies to enhance phenylalanine production, a key substrate for the synthesis of aromatic compounds. The ability of P. putida DOT-T1E to thrive with various C-sources and its tolerance to substrates, products, and potential toxicants in industrial wastes, are highlighted. The study identified and overcome possible bottlenecks for 2-PE production. Ultimately, the strains have potential to become efficient microbial platforms for synthesizing 2-PE from agro-industrial waste materials.

2.
Microb Cell Fact ; 23(1): 69, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38419048

RESUMO

We are interested in converting second generation feedstocks into styrene, a valuable chemical compound, using the solvent-tolerant Pseudomonas putida DOT-T1E as a chassis. Styrene biosynthesis takes place from L-phenylalanine in two steps: firstly, L-phenylalanine is converted into trans-cinnamic acid (tCA) by PAL enzymes and secondly, a decarboxylase yields styrene. This study focuses on designing and synthesizing a functional trans-cinnamic acid decarboxylase in Pseudomonas putida. To achieve this, we utilized the "wholesale" method, involving deriving two consensus sequences from multi-alignments of homologous yeast ferulate decarboxylase FDC1 sequences with > 60% and > 50% identity, respectively. These consensus sequences were used to design Pseudomonas codon-optimized genes named psc1 and psd1 and assays were conducted to test the activity in P. putida. Our results show that the PSC1 enzyme effectively decarboxylates tCA into styrene, whilst the PSD1 enzyme does not. The optimal conditions for the PSC1 enzyme, including pH and temperature were determined. The L-phenylalanine DOT-T1E derivative Pseudomonas putida CM12-5 that overproduces L-phenylalanine was used as the host for expression of pal/psc1 genes to efficiently convert L-phenylalanine into tCA, and the aromatic carboxylic acid into styrene. The highest styrene production was achieved when the pal and psc1 genes were co-expressed as an operon in P. putida CM12-5. This construction yielded styrene production exceeding 220 mg L-1. This study serves as a successful demonstration of our strategy to tailor functional enzymes for novel host organisms, thereby broadening their metabolic capabilities. This breakthrough opens the doors to the synthesis of aromatic hydrocarbons using Pseudomonas putida as a versatile biofactory.


Assuntos
Carboxiliases , Cinamatos , Pseudomonas putida , Estireno/metabolismo , Pseudomonas/genética , Pseudomonas/metabolismo , Carboxiliases/genética , Carboxiliases/metabolismo , Pseudomonas putida/metabolismo , Fenilalanina/metabolismo
3.
Microb Cell Fact ; 22(1): 22, 2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36732770

RESUMO

Pseudomonas putida DOT-T1E is a highly solvent tolerant strain for which many genetic tools have been developed. The strain represents a promising candidate host for the synthesis of aromatic compounds-opening a path towards a green alternative to petrol-derived chemicals. We have engineered this strain to produce phenylalanine, which can then be used as a raw material for the synthesis of styrene via trans-cinnamic acid. To understand the response of this strain to the bioproducts of interest, we have analyzed the in-depth physiological and genetic response of the strain to these compounds. We found that in response to the exposure to the toxic compounds that the strain can produce, the cell launches a multifactorial response to enhance membrane impermeabilization. This process occurs via the activation of a cis to trans isomerase that converts cis unsaturated fatty acids to their corresponding trans isomers. In addition, the bacterial cells initiate a stress response program that involves the synthesis of a number of chaperones and ROS removing enzymes, such as peroxidases and superoxide dismutases. The strain also responds by enhancing the metabolism of glucose through the specific induction of the glucose phosphorylative pathway, Entner-Doudoroff enzymes, Krebs cycle enzymes and Nuo. In step with these changes, the cells induce two efflux pumps to extrude the toxic chemicals. Through analyzing a wide collection of efflux pump mutants, we found that the most relevant pump is TtgGHI, which is controlled by the TtgV regulator.


Assuntos
Hidrocarbonetos Aromáticos , Pseudomonas putida , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Açúcares/metabolismo , Hidrocarbonetos Aromáticos/metabolismo , Solventes/metabolismo , Glucose/metabolismo
4.
Arch. pediatr. Urug ; 94(2): e216, 2023. tab
Artigo em Espanhol | LILACS, UY-BNMED, BNUY | ID: biblio-1520116

RESUMO

El síndrome inflamatorio multisistémico asociado a COVID-19 es una presentación postinfecciosa, que puede ser particularmente grave, pudiendo producir una severa disfunción multiorgánica. Se presenta una serie de 6 casos clínicos, asistidos en Servicio Médico Integral, Montevideo-Uruguay, con el fin de exponer las características clínicas y paraclínicas de este nuevo síndrome, y la evolución clínica de los mismos. Se realiza un estudio observacional descriptivo. La edad media fue de 6 años, con predominio en sexo femenino. Estos pacientes tuvieron una presentación clínica leve a moderada, con buena evolución Las manifestaciones clínicas principales fueron: fiebre, compromiso gastrointestinal, mucocutáneo y afectación ocular; dos de estos pacientes presentaron compromiso cardiovascular. Todos tuvieron alteraciones en la paraclínica, destacándose reactantes de fase aguda elevados. Todos los pacientes recibieron inmunoglobulina intravenosa y corticoides, tres de ellos recibieron heparina de bajo peso molecular por valor de D-dímeros 5 veces por encima del valor de referencia. No descartamos el impacto del diagnóstico y tratamiento precoz en la buena evolución de estos niños.


The Multisystem Inflammatory Syndrome associated with COVID-19 is a postinfectious presentation, which can be particularly serious, and can produce severe multiorgan dysfunction. A report of 6 clinical cases, assisted in the Comprehensive Medical Service, Montevideo-Uruguay, is presented in order to expose the clinical and paraclinical characteristics of this new syndrome, and their clinical evolution. A descriptive observational study was carried out. The mean age was 6 years, with a predominance of females. These patients had a mild to moderate clinical presentation, with good evolution. The main clinical manifestations were: fever, gastrointestinal and mucocutaneous involvement, and ocular involvement; two of these patients had cardiovascular compromise. All had alterations in the paraclinical, standing out elevated acute phase reactants. All patients received intravenous immunoglobulin and corticosteroids, three of them received low molecular weight heparin with a value of D-dimers 5 times higher than the reference value. We do not rule out the impact of early diagnosis and treatment on the positive evolution of these children.


A Síndrome Inflamatória Multissistêmica associada à COVID-19 é uma apresentação pósinfecciosa, que pode ser particularmente grave e produzir disfunção grave de múltiplos órgãos. Apresentamos um relato de 6 casos clínicos, atendidos no Serviço Médico Integral, Montevidéu-Uruguai, com o objetivo de expor as características clínicas e para clínicas desta nova síndrome, e sua evolução clínica. Tratase de um estudo observacional descritivo. A média de idade foi de 6 anos, com predomínio do sexo feminino. Esses pacientes tinham apresentação clínica leve a moderada, com boa evolução. As principais manifestações clínicas foram: febre, envolvimento gastrointestinal, muco cutâneo e ocular; dois desses pacientes apresentaram comprometimento cardiovascular. Todos apresentavam alterações para clínicas, destacandose elevados reagentes na fase aguda. Todos os pacientes receberam imunoglobulina e corticosteroides endovenosos, três deles receberam heparina de baixo peso molecular com valor do dímero D 5 vezes acima do valor de referência. Não descartamos o impacto do diagnóstico e tratamento precoces na evolução positiva dessas crianças.


Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Síndrome de Resposta Inflamatória Sistêmica/diagnóstico , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/tratamento farmacológico , COVID-19/complicações
5.
Arch. pediatr. Urug ; 94(1): e205, 2023. tab
Artigo em Espanhol | LILACS, UY-BNMED, BNUY | ID: biblio-1439316

RESUMO

Introducción: las infecciones fúngicas invasivas (IFI) son un problema de salud en creciente aumento. Objetivo: describir las características epidemiológicas, microbiológicas y clínicas de los menores de 15 años con IFI hospitalizados en el Hospital Pediátrico, Centro Hospitalario Pereira Rossell entre 2010- 2019. Metodología: estudio retrospectivo, mediante revisión de historias clínicas. Variables: edad, sexo, comorbilidades, factores de riesgo, clínica, patógenos, tratamiento y evolución. Resultados: se registraron 26 casos de IFI en 23 niños. La mediana de edad fue 8 años, de sexo femenino 17, con comorbilidades 17: infección por VIH 5, enfermedad hematooncológica 4. Todos presentaban factores de riesgo para IFI. Las manifestaciones clínicas de sospecha fueron: fiebre en 19, síntomas neurológicos 11, respiratorios 9, gastrointestinales 6, urinarios 2, sepsis/shock en 3. Los agentes identificados fueron: Candida spp en 14, Cryptococcus neoformans complex 8 y Aspergillus fumigatus complex 4. Tratamiento: se indicó fluconazol en 15, asociado a anfotericina B 11. Todas las infecciones por candida fueron sensibles a los azoles. Fallecieron 7 niños, la mediana de edad fue 1 año. En 4 se identificó Candida spp, Aspergillus fumigatus complex 2 y Cryptococcus neoformans complex 1. Conclusiones: las IFI son poco frecuentes, afectan en su mayoría a niños inmunocomprometidos asociando elevada mortalidad. El diagnóstico requiere alto índice de sospecha. Candida spp y Cryptococcus spp fueron los agentes más involucrados. El inicio precoz del tratamiento acorde a la susceptibilidad disponible se asocia a menor mortalidad.


Summary: Introduction: invasive fungal infections (IFI) are an increasing health problem. Objective: describe the epidemiological, microbiological and clinical characteristics of children under 15 years of age with IFI hospitalized at the Pereira Rossell Hospital Center between 2010-2019. Methodology: retrospective study, review of medical records. Variables: age, sex, comorbidities, risk factors, symptoms, pathogens, treatment and evolution. Results: 26 cases of IFI were recorded involving 23 children. Median age 8 years, female 17, comorbidities 17, HIV infection 5, hematological-oncological disease 4. All with risk factors. Suspicion symptoms: fever 19, neurological symptoms 11, respiratory 9, gastrointestinal 6, urinary 2, sepsis / shock 3. Identified agents: Candida spp 14, Cryptococcus neoformans complex 8 and Aspergillus fumigatus complex 4. Treatment: fluconazole 15, associated with amphotericin B 11. All candida infections were sensitive to azoles. 7 died, median age 1 year. In 4, Candida spp was isolated, Aspergillus fumigatus complex in 2 and Cryptococcus neoformans complex in 1. Conclusions: IFI are rare, mostly affecting immunocompromised children, associated with high mortality. The diagnosis requires a high index of suspicion. Candida spp and Cryptococcus spp were the most involved agents. Early treatment according to available susceptibility is associated with lower mortality.


Introdução: as infecções fúngicas invasivas (IFI) são um problema de saúde crescente. Objetivo: descrever as características epidemiológicas, microbiológicas e clínicas de crianças menores de 15 anos com IFI internadas no Centro Hospitalar Pereira Rossell entre 2010 e 2019. Metodologia: estudo retrospectivo, revisão de prontuários. Variáveis: idade, sexo, comorbidades, fatores de risco, sintomas, patógenos, tratamento e evolução. Resultados: foram registrados 26 casos de IFI em 23 crianças. Idade mediana 8 anos, sexo feminino 17, comorbidades 17, infecção por HIV 5, doença hemato-oncológica 4. Todos com fatores de risco. Suspeita clínica: febre 19, sintomas neurológicos 11, respiratórios 9, gastrointestinais 6, urinários 2, sepse/choque 3. Agentes identificados: Candida spp 14, Cryptococcus neoformans complexo 8 e Aspergillus fumigatus complexo 4. Tratamento: fluconazol 15, associado à anfotericina B 11. Todas as infecções por cândida foram sensíveis aos azóis. 7 morreram, idade média de 1 ano. Em 4 das crianças Cândida spp foi isolada, Aspergillus fumigatus complexo em 2 e Cryptococcus neoformans complexo em 1. Conclusões: IFIs são raras, afetando principalmente crianças imunocomprometidas, associadas a alta mortalidade. O diagnóstico requer alto índice de suspeita. Cândida spp e Cryptococcus spp são os agentes mais envolvidos. O tratamento precoce de acordo com a suscetibilidade disponível está associado a menor mortalidade.


Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Infecções Fúngicas Invasivas/tratamento farmacológico , Aspergilose/diagnóstico , Aspergilose/tratamento farmacológico , Aspergillus fumigatus , Comorbidade , Fluconazol/uso terapêutico , Criança Hospitalizada , Anfotericina B/uso terapêutico , Estudos Retrospectivos , Fatores de Risco , Hospedeiro Imunocomprometido/imunologia , Criptococose/diagnóstico , Criptococose/tratamento farmacológico , Cryptococcus neoformans , Candidíase Invasiva/diagnóstico , Candidíase Invasiva/tratamento farmacológico , Voriconazol/uso terapêutico , Infecções Fúngicas Invasivas/diagnóstico , Infecções Fúngicas Invasivas/mortalidade , Caspofungina/uso terapêutico , Antifúngicos/uso terapêutico
6.
Arch. pediatr. Urug ; 94(1): e207, 2023. tab
Artigo em Espanhol | LILACS, UY-BNMED, BNUY | ID: biblio-1439319

RESUMO

Introducción: en marzo del 2021 se registró el pico de incidencia de COVID-19 en Uruguay y un aumento de la infección en pediatría. Objetivo: describir las características clínicas, el tratamiento y la evolución de una serie de menores de 15 años con SIM-Ped S hospitalizados en dos centros de salud. Metodología: estudio descriptivo, retrospectivo, de los niños hospitalizados entre el 1/3 y el 31/6 de 2021 que cumplieron los criterios diagnósticos de SIM-Ped de la OMS. Se analizan variables clínicas, paraclínicas, tratamiento y evolución. Resultados: se incluyeron 12 niños, mediana de edad 7 años (22 meses-10 años). Se presentaron complicación posinfecciosas en 8 y en el curso de la infección en 4. Las manifestaciones fueron: fiebre (media 6 días, rango 3-10), digestivas 10 y mucocutáneas 7. Se presentaron como enfermedad Kawasaki símil 5 y como shock 2. La infección por SARS CoV-2 se confirmó por PCR en 6, serología 4 y test antigénico 2. Recibieron tratamiento en cuidados moderados 8 e intensivos 4: inmunoglobulina 9, corticoides 11, heparina 7 y ácido acetilsalicílico 7. Presentaron dilatación de arterias coronarias 2, alteraciones valvulares 2, disminución de la FEVI 2 y derrame pericárdico 2. Todos evolucionaron favorablemente. Conclusiones: en estos centros, los primeros casos de SIMS-Ped S coincidieron con el pico de incidencia de COVID-19 en el país. Predominaron las formas postinfecciosas en escolares con manifestaciones digestivas. Este estudio puede contribuir al reconocimiento de esta entidad y adecuar los algoritmos nacionales de manejo.


Introduction: in March 2021, there was a peak incidence of COVID-19 and an increase in pediatric infections in Uruguay. Objective: describe the clinical characteristics, treatment and evolution of a group of children under 15 years of age with SIM-Ped S hospitalized in two health centers. Methodology: descriptive, retrospective study of children hospitalized between 3/1 and 6/31 of 2021 who met the WHO diagnostic criteria for SIM-Ped. Clinical and paraclinical variables, as well as treatment and evolution were analyzed. Results: 12 children were included, median age 7 years (22 months-10 years). Eight of them showed post-infectious complications and 4 of them had complications during the course of the infection. The manifestations were: fever (mean 6 days, range 3-10), digestive symptoms 10 and mucocutaneous 7. Five of them presented a Kawasaki-like disease and 2 of them shock. SARS CoV-2 infection was confirmed by PCR in 6 cases, serology in 4 and antigenic test in 2. Eight of them received treatment in moderate care and 4 of them in intensive care: immunoglobulin 9, corticosteroids 11, heparin 7 and acetylsalicylic acid 7. Two of them presented dilated arteries coronary , valvular alterations 2, decreased LVEF 2 and pericardial effusion 2. All progressed favorably. Conclusions: in these centers, the first cases of SIMS-Ped S coincided with the peak incidence of COVID-19 in the country. Post-infectious forms predominated in schoolchildren who showed digestive manifestations. This study may contribute to the recognition of this entity and to the adaptation of national management algorithms.


Introdução: em março de 2021, foi registrado no Uruguai um pico de incidência da COVID-19 e um aumento dos casos da infecção pediátrica. Objetivo: descrever as características clínicas, tratamento e evolução de uma série de crianças menores de 15 anos com SIM-Ped S internadas em dois centros de saúde. Metodologia: estudo descritivo, retrospectivo, de crianças internadas entre 1/3 e 31/6 de 2021 que preencheram os critérios diagnósticos da OMS para o SIM-Ped. Foram analisadas variáveis clínicas e para-clinicas, tratamento e evolução. Resultados: foram incluídas 12 crianças, com idade média de 7 anos (22 meses-10 anos). Oito delas apresentaram complicações pós-infecciosas e 4 delas durante o curso da infecção. As manifestações foram: febre (média de 6 dias, intervalo 3-10), digestivas 10 e mucocutânea 7. Cinco delas apresentaram doença de Kawasaki-like e 2 delas sofreram Shock. A infecção por SARS CoV-2 foi confirmada por PCR em 6, sorologia em 4 e teste antigênico em 2. Oito delas receberam tratamento em cuidados moderados e 4 delas em cuidados intensivos: imunoglobulina 9, corticosteroides 11, heparina 7 e ácido acetilsalicílico 7. Duas delas apresentaram artérias coronárias dilatadas 2, alterações valvares 2, diminuição da FEVE 2 e derrame pericárdico 2. Todas evoluíram favoravelmente. Conclusões: nesses centros, os primeiros casos de SIMS-Ped S coincidiram com um pico de incidência de COVID-19 no país. As formas pós-infecciosas predominaram em escolares com manifestações digestivas. Este estudo pode contribuir para o reconhecimento desta entidade e adaptar algoritmos nacionais de gestão.


Assuntos
Humanos , Masculino , Feminino , Recém-Nascido , Lactente , Pré-Escolar , Criança , Síndrome de Resposta Inflamatória Sistêmica/complicações , COVID-19/complicações , Heparina/uso terapêutico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/tratamento farmacológico , Receptores de Glucocorticoides/uso terapêutico , Aspirina/uso terapêutico , Estudos Retrospectivos , Corticosteroides/uso terapêutico , Síndrome de Resposta Inflamatória Sistêmica/diagnóstico , Síndrome de Resposta Inflamatória Sistêmica/tratamento farmacológico , Doenças do Sistema Digestório/etiologia , Doenças do Sistema Digestório/tratamento farmacológico , Antipiréticos/uso terapêutico , Febre/etiologia , Febre/tratamento farmacológico , Avaliação de Sintomas , Antibacterianos/uso terapêutico , Síndrome de Linfonodos Mucocutâneos/etiologia , Síndrome de Linfonodos Mucocutâneos/tratamento farmacológico
7.
Environ Microbiol Rep ; 14(6): 934-946, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35651318

RESUMO

The extensive use of petrochemicals has produced serious environmental pollution problems; fortunately, bioremediation is considered an efficient way to fight against pollution. In line with Synthetic Biology is that robust microbial chassis with an expanded ability to remove environmental pollutants are desirable. Pseudomonas putida KT2440 is a robust lab microbe that has preserved the ability to survive in the environment and is the natural host for the self-transmissible TOL plasmid, which allows metabolism of toluene and xylenes to central metabolism. We show that the P. putida KT2440 (pWW0) acquired the ability to use octane as the sole C-source after acquisition of an almost 62-kb ICE from a microbial community that harbours an incomplete set of octane metabolism genes. The ICE bears genes for an alkane monooxygenase, a PQQ-dependent alcohol dehydrogenase and aldehyde dehydrogenase but lacks the electron donor enzymes required for the monooxygenase to operate. Host rubredoxin and rubredoxin reductase allow metabolism of octane to octanol. Proteomic assays and mutants unable to grow on octane or octanoic acid revealed that metabolism of octane is mediated by redundant host and ICE enzymes. Octane is oxidized to octanol, octanal and octanoic acid, the latter is subsequently acylated and oxidized to yield acetyl-CoA that is assimilated via the glyoxylate shunt; in fact, a knockout mutant in the aceA gene, encoding isocitrate lyase was unable to grow on octane or octanoic acid.


Assuntos
Pseudomonas putida , Pseudomonas putida/metabolismo , Proteômica , Octanos/metabolismo , Oxigenases de Função Mista/metabolismo , Octanóis/metabolismo
8.
Microb Biotechnol ; 15(4): 1026-1030, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35298878

RESUMO

Much of the energy being used to power our lives comes from fossil fuels such as coal, natural gas and petroleum. These energy sources are non-renewable, are being exhausted and also pollute the air, water and soil with toxic chemicals. Their mining, transportation, refining and use are associated with a large carbon footprint that contributes significantly to global warming. In addition, the geopolitical complexities surrounding the main fossil fuel producers create risks and uncertainties around the world. Replacing fossil fuels with clean, renewable forms of energy is paramount to creating a sustainable and healthy future, and for laying the foundations for global political stability and prosperity. Using biomass from plants, microbes can produce biofuels that are identical to or perform as well as fossil fuels. In addition of creating sustainable energy, advancing the biofuel industry will create new, high-quality rural jobs whilst improving energy security.


Assuntos
Biocombustíveis , Combustíveis Fósseis , Biomassa
9.
Microb Biotechnol ; 14(5): 1931-1943, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34403199

RESUMO

Pseudomonas putida is a highly solvent-resistant microorganism and useful chassis for the production of value-added compounds from lignocellulosic residues, in particular aromatic compounds that are made from phenylalanine. The use of these agricultural residues requires a two-step treatment to release the components of the polysaccharides of cellulose and hemicellulose as monomeric sugars, the most abundant monomers being glucose and xylose. Pan-genomic studies have shown that Pseudomonas putida metabolizes glucose through three convergent pathways to yield 6-phosphogluconate and subsequently metabolizes it through the Entner-Doudoroff pathway, but the strains do not degrade xylose. The valorization of both sugars is critical from the point of view of economic viability of the process. For this reason, a P. putida strain was endowed with the ability to metabolize xylose via the xylose isomerase pathway, by incorporating heterologous catabolic genes that convert this C5 sugar into intermediates of the pentose phosphate cycle. In addition, the open reading frame T1E_2822, encoding glucose dehydrogenase, was knocked-out to avoid the production of the dead-end product xylonate. We generated a set of DOT-T1E-derived strains that metabolized glucose and xylose simultaneously in culture medium and that reached high cell density with generation times of around 100 min with glucose and around 300 min with xylose. The strains grew in 2G hydrolysates from diluted acid and steam explosion pretreated corn stover and sugarcane straw. During growth, the strains metabolized > 98% of glucose, > 96% xylose and > 85% acetic acid. In 2G hydrolysates P. putida 5PL, a DOT-T1E derivative strain that carries up to five independent mutations to avoid phenylalanine metabolism, accumulated this amino acid in the medium. We constructed P. putida 5PLΔgcd (xylABE) that produced up to 250 mg l-1 of phenylalanine when grown in 2G pretreated corn stover or sugarcane straw. These results support as a proof of concept the potential of P. putida as a chassis for 2G processes.


Assuntos
Aminoácidos Aromáticos , Pseudomonas putida , Glucose , Lignina , Pseudomonas putida/genética , Xilose
17.
CBE Life Sci Educ ; 19(3): ar39, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32870092

RESUMO

The testing effect is one of the strongest learning techniques documented to date. Although the effects of testing on high-level learning are promising, fewer studies on this have been done. In this classroom application of the testing effect, we aimed to 1) determine whether a testing effect exists on high-level testing; 2) determine whether higher-level testing has an effect on low-level content retention; and 3) determine whether content knowledge, cognitive skill, or additional components are responsible for this effect. Through a series of two experiments, we confirmed a testing effect on high-level items. However, improved content retention due to testing was not observed. We suggest that this high-level testing effect is due to a better ability to apply specific skills to specific content when this application process has appeared on a previous exam.


Assuntos
Cognição , Aprendizagem
18.
Rev. méd. Urug ; 36(1): 6-11, mar. 2020. tab
Artigo em Espanhol | LILACS, BNUY | ID: biblio-1094221

RESUMO

Resumen: Introducción: la toxocariasis humana es una parasitosis de amplia distribución en el mundo cuyos agentes etiológicos son Toxocara canis y, en menor medida, Toxocara cati. Objetivo: describir las características clínicas y paraclínicas de toxocariasis en menores de 15 años asistidos en un prestador integral privado de Montevideo entre 2014 y 2018. Material y método: estudio descriptivo, retrospectivo, de los menores de 15 años derivados a la policlínica de infectología entre el 1 de enero de 2014 y el 31 de diciembre de 2018 con diagnóstico de toxocariasis confirmada por ELISA. Variables: edad, sexo, motivo de consulta, manifestaciones clínicas, recuento leucocitario y de eosinófilos, parasitosis asociadas, tratamiento y evolución. Resultados: fueron asistidos 20 niños de los cuales 11 eran asintomáticos, cinco presentaron síndrome de larva migrans visceral (LMV) y cuatro síndrome de larva migrans ocular (LO). Veinte niños recibieron albendazol y uno, además, mebendazol. Aquellos con compromiso ocular recibieron también corticoides vía oral. Se constató pérdida de agudeza visual en dos pacientes. Discusión y conclusiones: la mayorías de los niños eran asintomáticos, la cuarta parte consultaron por alteraciones visuales cuyas secuelas representan un grave problema de salud potencialmente prevenible. Debería realizarse la búsqueda de la infección mediante serología en niños que presenten eosinofilia con y sin síntomas respiratorios o disminución de la agudeza visual causada por lesión intraocular y en niños con factores de riesgo para esta parasitosis.


Summary: Introduction: human toxocariasis is a widely distributed parasitosis around the world. Its etiological agents are Toxocara canis and Toxocara cati in a smaller proportion. Objective: to describe the clinical and paraclinical manifestations of toxocariasis in children younger than 15 years old who were assisted in a private comprehensive healthcare provider in Montevideo between 2014 and 2018. Method: descriptive, retrospective study of children under 15 years old who were referred to the infectology service between January 1, 2014 and December 31, 2018 with a diagnosis of toxocariasis confirmed by ELISA. Variables were age, sex, reason of consultation, clinical manifestations, leukocyte and eosinophils count and associated parasitosis, treatment and evolution. Results: 20 children were assisted, 11 of them were asymptomatic, 5 evidenced visceral larva migrans (VLM) syndrome and 4 of them presented larva migrans ocular (LMO). 20 patients received albendazon and one of them also received mebendazol. Those whose eyes were compromised also received oral corticoids. Two patients presented loss of visual acuity. Discussion and conclusions: Most children were asymptomatic, 25% of them consulted for visual alterations whose sequelae represented a potentially preventable severe health problem. We need to make a greater effort to insist on eye control for children since alterations may be detected, avoiding sequelae with an early diagnosis and the right treatment.


Resumo: Introdução: a toxocaríase humana é uma parasitose com ampla distribuição em todo o mundo; seus agentes etiológicos são o Toxocara canis e menos frequentemente Toxocara cati. Objetivo: descrever as características clínicas e de laboratório de toxocaríase em menores de 15 anos atendidos em uma instituição privada de assistência integral de saúde em Montevidéu no período 2014-2018. Materiais e métodos: estudo descritivo, retrospectivo, dos menores de 15 anos referidos ao ambulatório de infectologia no período 1 de janeiro de 2014 - 31 de dezembro de 2018 com diagnóstico de toxocaríase confirmado por ELISA. Variáveis: idade, sexo, motivo de consulta, manifestações clínicas, contagem de leucócitos e de eosinófilos, parasitoses associadas, tratamento e evolução. Resultados: vinte crianças foram atendidas sendo: 11 assintomáticos, 5 com síndrome de larva migrans visceral (LMV) e 4 síndrome de síndrome de larva migrans ocular (LO). Todas foram medicadas com albendazol e uma recebeu também mebendazol. Aquelas com compromisso ocular tomaram também corticoides por via oral. Dois pacientes apresentaram perda da acuidade visual. Discussão e conclusões: a maioria das crianças eram assintomáticas, sendo que um quarto consultou por alterações visuais cujas sequelas representam um problema grave de saúde potencialmente previnivel. Devemos melhorar os esforços para insistir na realização de controle oftalmológico das crianças nos controles de saúde, pois com um diagnóstico precoce e tratamento adequado é possível detectar alterações e evitar sequelas.


Assuntos
Humanos , Recém-Nascido , Lactente , Pré-Escolar , Criança , Toxocaríase
20.
In. Giachetto Larraz, Gustavo A; Pardo Casaretto, Lorena Victoria; Speranza Mourine, María Noelia. Prescripción de antimicrobianos para infecciones frecuentes en pediatría. Montevideo, Bibliomédica, 2020. p.189-214.
Monografia em Espanhol | LILACS, UY-BNMED, BNUY | ID: biblio-1373301
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...