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1.
Org Biomol Chem ; 22(18): 3746-3751, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38652042

RESUMEN

A new methodology for the reduction of a wide variety of aliphatic and aromatic sulfoxides catalyzed by the air-stable, cheap and commercially available manganese catalyst MnBr(CO)5 with excellent yields is reported in this work. The catalytic system MnBr(CO)5/PhSiH3 is highly chemoselective, allowing the effective reduction of the SO bond in the presence of different functional groups.

2.
Development ; 147(3)2020 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-31969325

RESUMEN

Axon ensheathment is fundamental for fast impulse conduction and the normal physiological functioning of the nervous system. Defects in axonal insulation lead to debilitating conditions, but, despite its importance, the molecular players responsible are poorly defined. Here, we identify RalA GTPase as a key player in axon ensheathment in Drosophila larval peripheral nerves. We demonstrate through genetic analysis that RalA action through the exocyst complex is required in wrapping glial cells to regulate their growth and development. We suggest that the RalA-exocyst pathway controls the targeting of secretory vesicles for membrane growth or for the secretion of a wrapping glia-derived factor that itself regulates growth. In summary, our findings provide a new molecular understanding of the process by which axons are ensheathed in vivo, a process that is crucial for normal neuronal function.


Asunto(s)
Axones/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Unión al GTP Monoméricas/metabolismo , Vaina de Mielina/metabolismo , Nervios Periféricos/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animales , Animales Modificados Genéticamente , Fasciculación Axonal/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Larva/metabolismo , Locomoción/genética , Proteínas de Unión al GTP Monoméricas/genética , Mutación , Neuroglía/metabolismo , Interferencia de ARN
3.
Neurourol Urodyn ; 40(2): 680-687, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33476075

RESUMEN

AIMS: To investigate the intrarater reliability of visual inspection and digital palpation to classify women's ability to perform a voluntary pelvic floor muscle (PFM) contraction and the association between the two methods. METHODS: This was a test-retest clinical study including 44 women. The ability to perform a PFM voluntary contraction was evaluated two times in all participants using visual inspection and digital palpation. All analyzed participants were assessed with a 7-day interval between the two assessments and by the same examiner. Kappa's agreement coefficient was used to estimate the intrarater reliability, and Fisher's exact test was used to analyze association between the two methods. RESULTS: This study found a substantial intrarater reliability of visual inspection (k = 0.73; p < .001) and digital palpation (k = 0.74; p < .001). A significant association between visual inspection and digital palpation was found at both time points (p < .001). CONCLUSION: Both visual inspection and digital palpation have substantial intrarater reliability and visual inspection can be recommended when vaginal palpation is not tolerated.


Asunto(s)
Contracción Muscular/fisiología , Palpación/métodos , Diafragma Pélvico/fisiología , Adulto , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados
4.
Neurourol Urodyn ; 39(1): 361-366, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31737927

RESUMEN

AIMS: To assess women's self-perception of their pelvic floor muscle (PFM) contraction and its agreement with an assessed PFM contraction. Further, to assess a possible correlation between women's self-perception and reports of urinary incontinence (UI) and between PFM contraction and severity of UI. METHODS: A cross-sectional observational study including 82 women. The study was conducted in a basic healthcare unit in Brazil. PFM contraction was assessed by a physiotherapist and estimated by women using the Modified Oxford Scale (MOS). UI symptoms were assessed using a validated questionnaire (ICIQ-UI-SF). A descriptive analysis of the data was performed. The weighted κ coefficient, Spearman's correlation coefficient, and Fisher's exact test were used to analyze data. RESULTS: Eighty-two women with a mean age of 46.83 (±17.94) were analyzed. The majority (98.8%) believed they were able to voluntarily contract their PFM, but only 33% correctly estimated their PFM considering the examiner assessment as reference. No agreement (κ = 0.139, P = .087) was found between the examiner's classification and the women's estimation of their PFM contraction. Women's self-perception did not correlate with the ICIQ-IU-SF (r's = .011, P = .922). A moderate negative correlation was found between the assessed PFM contraction and the ICIQ-UI-SF score (r's = -.406, P = .00). CONCLUSION: Most of the women did not show an accurate self-perception of PFM contraction. No correlation between women's self-perception and the ICIQ-UI-SF score was found, but a negative correlation was found between the assessed PFM contraction and the ICIQ-UI-SF score.


Asunto(s)
Contracción Muscular/fisiología , Diafragma Pélvico/fisiología , Autoimagen , Incontinencia Urinaria/diagnóstico , Adulto , Brasil , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Diafragma Pélvico/fisiopatología , Encuestas y Cuestionarios , Incontinencia Urinaria/fisiopatología
5.
J Environ Manage ; 269: 110801, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32561010

RESUMEN

Convincing farmers to allot refuge areas for natural enemies is a challenge due to their fear of losing farming space. But, increasing the benefits beyond enhancing natural enemy conservation may further incentivize the adoption of refuge areas, which then would concomitantly favor biological control and other purposes. For example, the construction of terrace embankments on field slopes is essential to mitigate soil erosion; and this is better attained when vegetation occurs atop the terraces. Our insight is that these vegetated terraces can serve a dual purpose of preventing soil erosion as well as sheltering natural enemies and potentially diverting the attack of herbivorous pests. Therefore, in this two-year field study we assessed the abundance of natural enemies and pests as well as leaf damage and plant mass in maize plots cultivated between either vegetated or unvegetated terraces. The proportion of maize defoliation in the unvegetated-terrace treatment was about twice as high as the defoliation observed in the vegetated-terrace treatment during both years. The most abundant spontaneous vegetation occurring on the terraces comprised the grasses Panicum maximum Jacq. and Brachiaria decumbens (Stapf), which appeared to shelter herbivorous pests such as leafhoppers, spittlebugs and Chrysomelidae beetles as well as natural enemies. Specifically, a higher abundance of flying predators including wasps, ladybeetles and syrphids was observed in the vegetated-terrace treatment. Taken together, these results indicate the potential for vegetated terraces to concurrently mitigate soil erosion and promote pest control by means of enhancing natural enemy conservation as well as diverting pest attack.


Asunto(s)
Agricultura , Suelo , Control de Plagas , Control Biológico de Vectores , Poaceae
6.
Nitric Oxide ; 90: 29-36, 2019 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-31154004

RESUMEN

Nitric oxide (NO) presents innumerable biological roles, and its exogenous supplementation for therapeutic purposes has become a necessity. Some nanoporous materials proved to be potential vehicles for NO with high storage capacity. However, there is still a lack of information about their efficiency to release controlled NO and if they are biocompatible and biologically stable. In this work, we address this knowledge gap starting by evaluating the NO release and stability under biological conditions and their toxicity with primary keratinocyte cells. Titanosilicates (ETS-4 and ETS-10 types) and clay-based materials were the materials under study, which have shown in previous studies suitable NO gas adsorption/release rates. ETS-4 proved to be the most promising material, combining good biocompatibility at 180 µg/mL, stability and slower NO release. ETS-10 and ETAS-10 showed the best biocompatibility at the same concentration and, in the case of clay-based materials, CoOS is the least toxic of those tested and the one that releases the highest NO amount. The potentiality of these new NO donors to regulate biological functions was assessed next by controlling the mitochondrial respiration and the cell migration. NO-loaded ETS-4 regulates O2 consumption and cell migration in a dose-dependent manner. For cell migration, a biphasic effect was observed in a narrow range of ETS-4 concentration, with a stimulatory effect becoming inhibitory just by doubling ETS-4 concentration. For the other materials, no effective regulation was achieved, which highlights the relevance of the new assessment presented in this work for nanoporous NO carriers that will pave the way for further developments.


Asunto(s)
Materiales Biocompatibles/metabolismo , Queratinocitos/metabolismo , Mitocondrias/metabolismo , Óxido Nítrico/metabolismo , Porosidad , Adsorción , Materiales Biocompatibles/química , Movimiento Celular , Células Cultivadas , Células HeLa , Humanos , Queratinocitos/química , Mitocondrias/química , Óxido Nítrico/química , Tamaño de la Partícula , Propiedades de Superficie
9.
Org Biomol Chem ; 12(28): 5201-11, 2014 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-24915168

RESUMEN

Herein we present the synthesis and characterization of benzo[b]acridin-12(7H)-ones bearing carboranyl moieties and test their biological effectiveness as boron neutron capture therapy (BNCT) agents in cancer treatment. The cellular uptake of these novel compounds into the U87 human glioblastoma cells was evaluated by boron analysis (ICP-MS) and by fluorescence imaging (confocal microscopy). The compounds enter the U87 cells exhibiting a similar profile, i.e., preferential accumulation in the cytoskeleton and membranes and a low cytotoxic activity (IC50 values higher than 200 µM). The cytotoxic activity and cellular morphological alterations after neutron irradiation in the Portuguese Research Reactor (6.6 × 10(7) neutrons cm(-2) s(-1), 1 MW) were evaluated by the MTT assay and by electron microscopy (TEM). Post-neutron irradiation revealed that BNCT has a higher cytotoxic effect on the cells. Accumulation of membranous whorls in the cytoplasm of cells treated with one of the compounds correlates well with the cytotoxic effect induced by radiation. Results provide a strong rationale for considering one of these compounds as a lead candidate for a new generation of BNCT agents.


Asunto(s)
Acridonas/síntesis química , Antineoplásicos/síntesis química , Compuestos de Boro/síntesis química , Neuroglía/efectos de los fármacos , Neutrones , Acridonas/farmacología , Citoesqueleto de Actina/efectos de los fármacos , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/efectos de la radiación , Citoesqueleto de Actina/ultraestructura , Antineoplásicos/farmacología , Transporte Biológico , Compuestos de Boro/farmacología , Terapia por Captura de Neutrón de Boro/métodos , Línea Celular Tumoral , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Membrana Celular/efectos de la radiación , Membrana Celular/ultraestructura , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Humanos , Microscopía Confocal , Neuroglía/metabolismo , Neuroglía/efectos de la radiación , Neuroglía/ultraestructura
10.
Sensors (Basel) ; 14(8): 15496-524, 2014 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-25196163

RESUMEN

Flow cytometers have been optimized for use in portable platforms, where cell separation, identification and counting can be achieved in a compact and modular format. This feature can be combined with magnetic detection, where magnetoresistive sensors can be integrated within microfluidic channels to detect magnetically labelled cells. This work describes a platform for in-flow detection of magnetically labelled cells with a magneto-resistive based cell cytometer. In particular, we present an example for the validation of the platform as a magnetic counter that identifies and quantifies Streptococcus agalactiae in milk.


Asunto(s)
Bacterias/aislamiento & purificación , Técnicas Biosensibles/métodos , Citometría de Flujo/métodos , Dispositivos Laboratorio en un Chip , Animales , Bacterias/patogenicidad , Bovinos , Humanos , Leche/microbiología
11.
Chem Soc Rev ; 41(17): 5641-53, 2012 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-22786441

RESUMEN

High-valent oxo-complexes have recently emerged as powerful catalysts for the activation of X-H (X = Si, B, P and H) bonds and for the reduction of several functional groups. This new reactivity represents a complete reversal from the traditional role of these complexes as oxidation catalysts and opened a new research area for high-valent oxo-complexes. This tutorial review highlights the work developed using high-valent oxo-molybdenum and oxo-rhenium complexes as excellent catalysts for X-H (X = Si, B, P and H) bond activation and for organic reductions.

12.
Nutr Bull ; 48(2): 160-178, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37161615

RESUMEN

Qualitative menu labelling can be defined as descriptive or non-numerical interpretive labels (e.g. traffic light labelling, healthy food symbols, messages or ingredient lists). Qualitative information seems to have a positive influence on consumers' food choices, particularly in institutional food service establishments, such as in universities. The aim of this systematic review was to assess the influence of different formats of qualitative menu labelling on food choices in university restaurants. This systematic review was guided by the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) and Synthesis Without Meta-Analysis (SWiM) and conducted vote counting of studies based on the direction of effect. Studies were retrieved from Cochrane Library, Scopus, MEDLINE, LILACS, SciELO and Web of Science databases and reference lists of selected articles. Experimental and quasi-experimental studies were included. Two independent researchers searched and extracted the data and assessed the methodological quality using the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. From the initial search (460 records), four papers were selected, plus one paper identified in a previous study and a further six from an update search, totalling 11 included studies, reporting 14 different interventions (n = 499 174). Types of interventions included the use of symbols and the inclusion of traffic light labelling. Outcomes of interest were food choice, expressed as mean, median or percent healthy food choices or purchases. Qualitative menu labels increased healthy food choices and/or purchase behaviour, with 10 of 12 interventions favouring the intervention (83%; 95%CI 55-95%; p = 0.0386). Most of the studies favouring the intervention used healthy food symbols for healthier foods or food components, alone or in association with another intervention and were of moderate and weak quality. These findings may serve as a basis for the implementation of nutrition information policies in university restaurants.


Asunto(s)
Preferencias Alimentarias , Restaurantes , Humanos , Universidades
13.
Braz Dent J ; 33(4): 62-70, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36043570

RESUMEN

Proanthocyanidin (PA) is a promising dentin biomodifier due to its ability to stabilize collagen fibrils against degradation by matrix metalloproteinases (MMPs); however, the most effective protocol to incorporate PA into bonding procedures is still unclear. This study evaluated the effect of dentin biomodification with a PA acid etchant on MMP activity, adhesive interface morphology and resin-dentin microtensile bond strength. Sound extracted human molars were flattened to expose dentin and acid-etched for 15 s according to the groups: EXP - experimental phosphoric acid; EXP+PA - experimental phosphoric acid 10% PA; TE - total-etching system; SE - self-etching system. Samples were restored with composite resin and stored in distilled water (37ºC). MMP activity and interface morphology were analyzed after 24 h by in situ zymography (n=6) and scanning electron microscopy (n=3), respectively. The resin-dentin microtensile bond strength (µTBS) was evaluated after 24 h and 6 months storage (n=6). Significantly higher MMP activity was detected in etched dentin compared with untreated dentin (p<0.05), but no difference among acid groups was found. Resin tags and microtags, indicative of proper adhesive system penetration in dentinal tubules and microtubules, were observed along the hybrid layer in all groups. There was no difference in µTBS between 24 h and 6 months for EXP+PA; moreover, it showed higher long-term µTBS compared with TE and EXP (p<0.05). The results suggest that 15 s of biomodification was not sufficient to significantly reduce MMP activity; nonetheless, EXP+PA was still able to improve resin-dentin bond stability compared with total- and self-etching commercial systems.


Asunto(s)
Recubrimiento Dental Adhesivo , Proantocianidinas , Grabado Ácido Dental/métodos , Resinas Compuestas/química , Recubrimiento Dental Adhesivo/métodos , Cementos Dentales , Dentina/química , Recubrimientos Dentinarios/química , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Ácidos Fosfóricos , Proantocianidinas/análisis , Proantocianidinas/química , Cementos de Resina/química , Resistencia a la Tracción
14.
Toxics ; 10(6)2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35736908

RESUMEN

The formation of complexes of the drug 5-fluorouracil (5-FU) with ß-cyclodextrin (ß-CD) and sodium dodecyl sulphate (SDS) was studied through experimental measurements of the ternary mutual diffusion coefficients (D11, D22, D12, and D21) for the systems {5-FU (component 1) + ß-CD (component 2) + water} and {5-FU (component 1) + SDS (component 2) + water} at 298.15 K and at concentrations up to 0.05 mol dm-3 by using the Taylor dispersion method, with the objective of removing this polluting drug from the residual systems in which it was present. The results found showed that a coupled diffusion of 5-FU occurred with both ß-CD and SDS, as indicated by the nonzero values of the cross-diffusion coefficients, D12 and D21, as a consequence of the complex formation between 5-FU and the ß-CD or SDS species. That is, 5-FU was solubilized (encapsulated) by both carriers, although to a greater extent with SDS (K = 20.0 (±0.5) mol-1 dm3) than with ß-CD (K = 10.0 (±0.5) mol-1 dm3). Values of 0.107 and 0.190 were determined for the maximum fraction of 5-FU solubilized with ß-CD and SDS (at concentrations above its CMC), respectively. This meant that SDS was more efficient at encapsulating and thus removing the 5-FU drug.

15.
ChemSusChem ; 14(19): 4228-4233, 2021 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-33667328

RESUMEN

Plastic pollution is one of the biggest problems all over the world. Beyond change/awareness of consumer behavior, there is an urgent need to search for efficient, economical and environmentally friendly catalysts for the valorization of plastic waste to value-added compounds. This work describes the reductive depolymerization of several types of plastic waste into value-added compounds, including 1,6-hexanediol, 1,2-propanediol, p-xylene and tetrahydrofuran, in good yields using the eco-friendly, air-stable, commercially available and very cheap catalyst Zn(OAc)2 ⋅ 2H2 O. This is the first example of the reductive depolymerization of polyester waste catalyzed by a zinc catalyst. Moreover, the catalytic system silane/Zn(OAc)2 ⋅ 2H2 O was successfully applied to the reduction of polycaprolactone (PCL) on the gram scale with good yield and also to the selective reductive depolymerization of plastic mixtures. Finally, this work demonstrated that the catalyst Zn(OAc)2 ⋅ 2H2 O can be used in at least 7 cycles with good yields.

16.
J Dev Biol ; 9(1)2021 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-33572886

RESUMEN

Spondylocostal dysostosis (SCDO) is a rare heritable congenital condition, characterized by multiple severe malformations of the vertebrae and ribs. Great advances were made in the last decades at the clinical level, by identifying the genetic mutations underlying the different forms of the disease. These were matched by extraordinary findings in the Developmental Biology field, which elucidated the cellular and molecular mechanisms involved in embryo body segmentation into the precursors of the axial skeleton. Of particular relevance was the discovery of the somitogenesis molecular clock that controls the progression of somite boundary formation over time. An overview of these concepts is presented, including the evidence obtained from animal models on the embryonic origins of the mutant-dependent disease. Evidence of an environmental contribution to the severity of the disease is discussed. Finally, a brief reference is made to emerging in vitro models of human somitogenesis which are being employed to model the molecular and cellular events occurring in SCDO. These represent great promise for understanding this and other human diseases and for the development of more efficient therapeutic approaches.

17.
Nutr Rev ; 79(7): 788-801, 2021 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-33313917

RESUMEN

CONTEXT: Reducing population intakes of sugar has become a focus of many national and international public health policies. Packaged foods and beverages are key contributors to sugar intakes, and food labels can be an effective tool to reduce sugar consumption. OBJECTIVE: The aim of this systematic review was to examine the influence of sugar label formats on 2 outcomes: consumers' understanding of sugar information, and the amount of sugar in consumers' food choices. DATA SOURCES: Scopus, Web of Science, PubMed, CAB Abstracts, SciELO, and the Cochrane Library databases were searched up until February 4, 2020. STUDY SELECTION: Randomized experiments or quasi-experiments were included if they investigated the influence of sugar label formats on consumers' understanding of sugar information or on the amount of sugar in consumers' food choices. DATA EXTRACTION: Data were extracted independently by 2 authors. Mean differences (MDs), standardized mean differences (SMDs), and odds ratios (ORs) plus 95%CIs were used to describe between-group differences for intervention label formats using random-effects models. RESULTS: Twenty-three studies, which examined 39 comparisons, were included. Label formats using "high in sugar" interpretative texts (traffic light labels [MD 41.6; 95%CI 37.9-45.4] and warning signs [OR 1.33; 95%CI 1.0-1.78]) were most effective in increasing consumers' understanding of the sugar content in packaged foods. Health warning messages (SMD -0.32; 95%CI -0.43 to -0.22), graphical depictions of sugar content in teaspoons (SMD -0.32; 95%CI -0.48 to -0.17), and warning signs (SMD -0.24; 95%CI -0.35 to -0.13) were most effective for influencing consumers to choose products with lower sugar content. CONCLUSIONS: Formats that provide an interpretation of sugar information, particularly those indicating if a product is high in sugar, were more helpful than only numerical information for improving consumer understanding and promoting food choices with less sugar. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number CRD42018081222.


Asunto(s)
Comportamiento del Consumidor , Etiquetado de Alimentos , Preferencias Alimentarias , Azúcares , Bebidas , Conducta de Elección , Comportamiento del Consumidor/estadística & datos numéricos , Etiquetado de Alimentos/normas , Humanos
18.
J Phys Chem A ; 114(12): 4188-96, 2010 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-20199045

RESUMEN

Three water-insoluble, micelle-anchored flavylium salts, 7-hydroxy-3-octyl-flavylium chloride, 4'-hexyl-7-hydroxyflavylium chloride, and 6-hexyl-7-hydroxy-4-methyl-flavylium chloride, have been employed to probe excited-state prototropic reactions in micellar sodium dodecyl sulfate (SDS). In SDS micelles, the fluorescence decays of these three flavylium salts are tetraexponential functions in the pH range from 1.0 to 4.6 at temperatures from 293 to 318 K. The four components of the decays are assigned to four kinetically coupled excited species in the micelle: specifically, promptly deprotonable (AH(+)*) and nonpromptly deprotonable (AH(h)(+)*) orientations of the acid in the micelle, the base-proton geminate pair (A*...H(+)), and the free conjugate base (A*). The initial prompt deprotonation to form the geminate pair occurs at essentially the same rate (k(d) approximately 6-7 x 10(10) s(-1)) for all three photoacids. Recombination of the geminate pair is approximately 3-fold faster than the rate of proton escape from the pair (k(rec) approximately 3 x 10(10) s(-1) and k(diss) approximately 1 x 10(10) s(-1)), corresponding to an intrinsic recombination efficiency of the pair of approximately 75%. Finally, the reprotonation of the short-lived free A* (200-350 ps, depending on the photoacid) has two components, only one of which depends on the proton concentration in the intermicellar aqueous phase. Ultrafast transfer of the proton to water and substantial compartmentalization of the photogenerated proton at the micelle surface on the picosecond time scale strongly suggest preferential transfer of the proton to preformed hydrogen-bonded water bridges between the photoacid and the anionic headgroups. This localizes the proton in the vicinity of the excited base much more efficiently than in bulk water, resulting in the predominance of geminate reprotonation at the micelle surface.

19.
Front Microbiol ; 11: 574550, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33488531

RESUMEN

Rock phosphate (RP) is a natural source of phosphorus for agriculture, with the advantage of lower cost and less impact on the environment when compared to synthetic fertilizers. However, the release of phosphorus (P) from RP occurs slowly, which may limit its short-term availability to crops. Hence, the use of P-solubilizing microorganisms to improve the availability of P from this P source is an interesting approach, as microorganisms often perform other functions that assist plant growth, besides solubilizing P. Here, we describe the characterization of 101 bacterial isolates obtained from the rhizosphere and endosphere of maize plants for their P solubilizing activity in vitro, their growth-promoting activity on millet plants cultivated in soil amended with RP, and their gene content especially associated with phosphate solubilization. For the in vitro solubilization assays, two mineral P sources were used: rock phosphate from Araxá (Brazil) mine (AP) and iron phosphate (Fe-P). The amounts of P released from Fe-P in the solubilization assays were lower than those released from AP, and the endophytic bacteria outperformed the rhizospheric ones in the solubilization of both P sources. Six selected strains were evaluated for their ability to promote the growth of millet in soil fertilized with a commercial rock phosphate (cRP). Two of them, namely Bacillus megaterium UFMG50 and Ochrobactrum pseudogrignonense CNPMS2088, performed better than the others in the cRP assays, improving at least six physiological traits of millet or P content in the soil. Genomic analysis of these bacteria revealed the presence of genes related to P uptake and metabolism, and to organic acid synthesis. Using this approach, we identified six potential candidates as bioinoculants, which are promising for use under field conditions, as they have both the genetic potential and the experimentally demonstrated in vivo ability to improve rock phosphate solubilization and promote plant growth.

20.
N Biotechnol ; 56: 27-37, 2020 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-31704414

RESUMEN

Design and development of scale-down approaches, such as microbioreactor (µBR) technologies with integrated sensors, are an adequate solution for rapid, high-throughput and cost-effective screening of valuable reactions and/or production strains, with considerably reduced use of reagents and generation of waste. A significant challenge in the successful and widespread application of µBRs in biotechnology remains the lack of appropriate software and automated data interpretation of µBR experiments. Here, it is demonstrated how mathematical models can be usedas helpful tools, not only to exploit the capabilities of microfluidic platforms, but also to reveal the critical experimental conditions when monitoring cascade enzymatic reactions. A simplified mechanistic model was developed to describe the enzymatic reaction of glucose oxidase and glucose in the presence of catalase inside a commercial microfluidic platform with integrated oxygen sensor spots. The proposed model allowed an easy and rapid identification of the reaction mechanism, kinetics and limiting factors. The effect of fluid flow and enzyme adsorption inside the microfluidic chip on the optical sensor response and overall monitoring capabilities of the presented platform was evaluated via computational fluid dynamics (CFD) simulations. Remarkably, the model predictions were independently confirmed for µL- and mL- scale experiments. It is expected that the mechanistic models will significantly contribute to the further promotion of µBRs in biocatalysis research and that the overall study will create a framework for screening and evaluation of critical system parameters, including sensor response, operating conditions, experimental and microbioreactor designs.


Asunto(s)
Reactores Biológicos , Catalasa/metabolismo , Glucosa Oxidasa/metabolismo , Técnicas Analíticas Microfluídicas , Modelos Biológicos , Fibras Ópticas , Biocatálisis
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