Produção e consumo de acetato em cultivos de Salmonella typhimurium em condições aeróbias

Linhagens atenuadas de Salmonella typhimurium têm sido amplamente estudadas para o desenvolvimento de diversas vacinas e no tratamento do câncer. No entanto, ainda há poucas informações a respeito de seu metabolismo. S. typhimurium e Escherichia coli apresentam grande similaridade em seus genomas e redes metabólicas. Com o intuito de avaliar o metabolismo da Salmonella sob condições aeróbias, realizou-se seis cultivos contínuos nas taxas de diluição de 0,1 a 0,67 h-1 utilizando glicose como substrato. Estes resultados demonstraram um desvio de carbono para a formação de acetato, a partir da taxa de diluição de 0,1 h-1, diferentemente do que é relatado para E. coli, onde o acúmulo de acetato é detectado somente em taxas de diluição acima de 0,4 h-1. Investigou-se ainda a assimilação do acetato em cultivos em batelada, utilizando ácido acético como substrato principal. Os resultados obtidos confirmaram que a Salmonella possui um fluxo de assimilação de acetato menor do que a E. coli. Apesar de ambos os microrganismos apresentarem as mesmas reações no metabolismo central do carbono, este trabalho apresenta evidências experimentais que demonstram a menor capacidade de S. typhimurium em direcionar os fluxos de carbono para biomassa e produção de energia, caracterizada pela maior formação de acetato. A produção de acetato é considerada um desperdício de carbono, diminuindo a produtividade e os rendimentos, e comprometendo a obtenção de alta densidade celular essencial para o desenvolvimento de vacinas recombinantes de baixo custo. A análise dos fluxos metabólicos pode contribuir para minimizar a formação deste subproduto indesejado, tornando o metabolismo mais eficiente

Salmonella typhimurium and Escherichia coli dissimilarity: closely related bacteria with distinct metabolic profiles

Live attenuated strains of Salmonella typhimurium have been extensively investigated as vaccines for a number of infectious diseases. However, there is still little information available concerning aspects of their metabolism. S. typhimurium and Escherichia coli show a high degree of similarity in terms of their genome contents and metabolic networks. However, this work presents experimental evidence showing that significant differences exist in their abilities to direct carbon fluxes to biomass and energy production. It is important to study the metabolism of Salmonella in order to elucidate the formation of acetate and other metabolites involved in optimizing the production of biomass, essential for the development of recombinant vaccines. The metabolism of Salmonella under aerobic conditions was assessed using continuous cultures performed at dilution rates ranging from 0.1 to 0.67 h1, with glucose as main substrate. Acetate assimilation and glucose metabolism under anaerobic conditions were also investigated using batch cultures. Chemostat cultivations showed deviation of carbon towards acetate formation, starting at dilution rates above 0.1 h1. This differed from previous findings for E. coli, where acetate accumulation was only detected at dilution rates exceeding 0.4 h1, and was due to the lower rate of acetate assimilation by S. typhimurium under aerobic conditions. Under anaerobic conditions, both microorganisms mainly produced ethanol, acetate, and formate. A genome-scale metabolic model, reconstructed for Salmonella based on an E. coli model, provided a poor description of the mixed fermentation pattern observed during Salmonella cultures, reinforcing the different patterns of carbon utilization exhibited by these closely related bacteria. This article is protected by copyright. All rights reserved.Special thanks to Amadeus Azevedo for the HPLC analyses and technical assistance. The authors acknowledge the national funding received from CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil), the international cooperation project CAPES-FCT (Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior/Brazil-Fundacao para a Ciencia e a Tecnologia/Portugal-Process 315/11), CAPES (Atracao de Jovens Talentos-Process 064922/2014-01) and to Fundacao para a Ciencia e Tecnologia the strategic funding of UID/BIO/04469/2013 unit

Processo de transferência de tecnologia da universidade para a indústria: estudo de caso envolvendo a conversão de glicerol

Currently, public policy has encouraged innovation in universities and also transference of technology to the industry. Another important stage to be considered would be the registration or filing of a patent and the economical viability study. Government programs, such as the innovation incentive program, among others, should facilitate popularization and promote interest by industry. In this work we described the steps, from the conception of the idea to the scale up going through its interest by the industry. The case study is about the glycerol conversion utilizing modified niobia as catalysts

Analysis of Salmonella typhimurium pathways and metabolic model improvement

Live attenuated strains of Salmonella typhimurium have been extensively investigated as vaccines for several infectious diseases. However, a better knowledge of S. typhimurium metabolism is required to develop protocols to improve bioprocesses for the production of biotechnological products in large scale. Currently, genome scale metabolic models are important tools for better understanding the phenotypic behavior of many microorganisms. In this work, a genome-scale metabolic model reconstructed for S. typhimurium (STMv1.0 model) was used to determine the in silico fluxes distributions of end-products and to compare with in vivo data. Experimental data from glucose-limited chemostat at different dilution rates (0.1 to 0.67 h-1) with S. typhiumurium LT2 were compared with in silico simulations performed with Optflux 3.2.4 software, using the same environmental conditions (glucose and O2 experimental uptake fluxes). Salmonella cultures showed deviation of carbon towards acetate formation, starting at dilution rate above 0.1 h-1, with flux of 4.16 mmol acetate/(gDCW . h) at the higher dilution rate. Nevertheless, this model, which was based on E. coli model, overestimates the biomass production and, consequently, minimizes the fluxes of acetate. Thus, changes in metabolic model are required to improve its accuracy to predict the fermentation patterns observed experimentally, including changes in model equations related to P/O ratio and ATP yield. 13C Fluxomic analysis are being carried out to better understand the S. typhimurium central carbon metabolism and to improve the model predictions

Antimicrobial and leishmanicidal activities of seeds of Pterodon emarginatus

The present work investigated the antimicrobial and leishmanicidal activities of seeds of Pterodon emarginatus. The tests of diffusion in agar (10, 25 and 50 mg) and determination of minimum inhibitory concentration (MIC) were performed using essential oil (EO) obtained from seeds using the standard microorganisms: Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC 25175, Pseudomonas aeruginosa ATCC 90271, Escherichia coli ATCC 10530 and Candida albicans ATCC 10231. Leishmanicidal activity of the EO and fractions (6.25 – 100 µg/ml) obtained of seeds of P. emarginatus was evaluated in vitro using L. amazonensis and L. chagasi promastigote forms. The EO inhibited the growth of S. aureus (MIC = 2.5 mg/ml). The hexane (IC50 = 50.06 µg/ ml) and butanol (IC50 = 46.65 µg/ml) fractions showed activity against L. amazonensis promastigote forms, but did not against L. chagasi promastigote forms. The results indicate that the bioactive molecules present in the seeds of P. emarginatus can be used as prototype for the development of drug and/or as source pharmaceutical material.O presente trabalho investigou as atividades antimicrobiana e leishmanicida das sementes de Pterodon emarginatus Vogel. O potencial antimicrobiano do óleo essencial (OE) obtido das sementes foi avaliado através dos testes de difusão em ágar (10, 25 e 50 mg) e determinação da concentração inibitória mínima e utilizou os microorganismos-padrão: Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC 25175, Pseudomonas aeruginosa ATCC 90271, Escherichia coli ATCC 10530 e Candida albicans ATCC 10231. A atividade leishmanicida do OE e frações (6,25 – 100 µg/mL) obtidas das sementes de P. emarginatus foram testadas, in vitro, sobre formas promastigotas de L. amazonensis e L. chagasi. O OE das sementes de P. emarginatus inibiu o crescimento somente de S. aureus (CIM = 2,5 mg/mL). As frações hexânica (IC50 = 50,06 µg/mL) e butanólica (IC50 = 46,65 µg/mL) apresentaram atividade frente às formas promastigotas de L. amazonensis, porém não apresentaram atividade frente a L. chagasi. Os resultados indicam que as moléculas bioativas presentes nas sementes de P. emarginatus podem ser utilizadas como protótipos para o desenvolvimento de fármacos e/ou como fonte de matérias-primas farmacêuticas

Improved photocatalytic activity of d-FeOOH by using H2O2 as an electron acceptor.

In this work, d-FeOOH nanoparticles were synthesized by a simple co-precipitation method and used as a photocatalyst in the presence of H2O2 for the oxidation of Rhodamine B (RhB) dye under artificial light. The d-FeOOH was characterized by powder X-ray diffraction, 57Fe M?ssbauer spectroscopy, N2 adsorption/desorption and UV?vis diffuse reflectance measurements. The d-FeOOH nanoparticles have high specific surface area (101 m2 g 1) and optical bandgap energy of 2.02 eV. Under artificial light, only 59% of RhB (100 mL; 20 mg L 1) was photocatalytically degraded by d-FeOOH in 60 min reaction. However, after adding H2O2, the photocatalytic activity of d-FeOOH was significantly improved, reaching 87% of dye removal. Tests using scavengers of reactive species and EPR analysis revealed that h+ and OH are the main species in this system. Based on the experimental results, the mechanism of RhB photodegradation in the presence of d-FeOOH and H2O2 was proposed. By this mechanism, the OH can be formed by direct water oxidation or by H2O2 reduction, as the electron transfer from the conduction band of d-FeOOH to H2O2 is thermodynamically favorable. Moreover, the H2O2 retards the electron-hole recombination in d-FeOOH, thus increasing its photocatalytic activity. Given its high efficiency for degrading RhB in water, d-FeOOH revealed to be a promising photocatalyst to be tested in the oxidation of emerging pollutants for the environmental decontamination

Clinical and Urodynamic results of the Argus T® sling in moderate and severe male stress urinary incontinence after radical prostatectomy – a 5 year prospective study.

ABSTRACT Purpose: Sling as a therapeutic option for male stress urinary incontinence (SUI) has been reviewed in the last two decades, as it is a relatively simpliest surgery compared to artificial urinary sphincter and has the ability to modulate urethral compression. This study aims to evaluate the efficacy, rate of complications, quality of life and the effects on bladder emptying of the Argus T® compressive and ajustable sling in moderate and severe male SUI treatment. Materials and Methods: Men eligible for stress urinary incontinence treatment after radical prostatectomy were recruited and prospectively evaluated, from March 2010 to November 2016. It was selected outpatient men with moderate and severe SUI, after 12 months of radical prostatectomy, who have failed conservative treatment. All patients had a complete clinical and urodynamic pre and post treatment evaluation, by means of clinical history, physical examination, urine culture, 1-hour pad test and ICIq-SF questionnaire. The UDS was performed after 12, 18 and 24 months postoperatively. Results: Thirty-seven men underwent sling surgery, 19 patients (51.4%) with moderate and 18 (48.6%) with severe SUI. The minimum follow-up time was 5 years. Overall, we had a success rate of 56.7% at 60 months follow-up. After surgery, we did not observe significant changes in the urodynamic parameters evaluated during the follow-up. No patient had urodynamic bladder outlet obstruction (BOO) after sling implantation. Readjustment of the Argus T® sling was performed in 16 (41%) of the patients and 51% of the patients reported some adverse event. Conclusion: We demonstrate a long-term efficacy and safety of Sling Argus T® as an alternative to moderate and severe male SUI treatment. Furthermore, in our study bulbar urethra compression does not lead to bladder outlet obstruction

Cellulosic films obtained from the treatment of sugarcane bagasse fibers with N -methylmorpholine- N -oxide (NMMO)

Ethanol/water organosolv pulping was used to obtain sugarcane bagasse pulp that was bleached with sodium chlorite. This bleached pulp was used to obtain cellulosic films that were further evaluated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). A good film formation was observed when temperature of 74 °C and baths of distilled water were used, which after FTIR, TGA, and SEM analysis indicated no significant difference between the reaction times. The results showed this to be an interesting and promising process, combining the prerequisites for a more efficient utilization of agro-industrial residues.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil; Fundação para a Ciência e a Tecnologia (FCT) and CEMU

A hole inversion layer at the BiVO4/Bi4V2O11 interface produces a high tunable photovoltage for water splitting

The conversion of solar energy into hydrogen fuel by splitting water into photoelectrochemical cells (PEC) is an appealing strategy to store energy and minimize the extensive use of fossil fuels. The key requirement for efficient water splitting is producing a large band bending (photovoltage) at the semiconductor to improve the separation of the photogenerated charge carriers. Therefore, an attractive method consists in creating internal electrical fields inside the PEC to render more favorable band bending for water splitting. Coupling ferroelectric materials exhibiting spontaneous polarization with visible light photoactive semiconductors can be a likely approach to getting higher photovoltage outputs. The spontaneous electric polarization tends to promote the desirable separation of photogenerated electron- hole pairs and can produce photovoltages higher than that obtained from a conventional p-n heterojunction. Herein, we demonstrate that a hole inversion layer induced by a ferroelectric Bi4V2O11 perovskite at the n-type BiVO4 interface creates a virtual p-n junction with high photovoltage, which is suitable for water splitting. The photovoltage output can be boosted by changing the polarization by doping the ferroelectric material with tungsten in order to produce the relatively large photovoltage of 1.39?V, decreasing the surface recombination and enhancing the photocurrent as much as 180%.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq