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•Prebiotics and dietary fibers modulate HGM diversity after ingestion.•Prebiotics and dietary fibers fermentations by HGM produce bioactive metabolites.•Bacterial SCFA’s participate ...in specific mechanisms related to host health benefits.•The intake of prebiotics and dietary fibers generates health benefits.
Human gut microbiota (HGM) is a microbial complex where dynamic mutualistic interactions related to digestion and absorption of dietary components take place. The consumption of specific food ingredients, such as prebiotics and dietary fibers, constituted mainly by carbohydrates polymers, can modulate the HGM composition and metabolism serving as a fermentable substrate to produce bacterial metabolites with beneficial effects on host health. Especially, bacterial short-chain fatty acids, tryptophan and organic acids have shown positive effects on pathogenic bacteria control, mineral absorption, weight control and obesity, immune response homeostasis, gut barrier improvement, brain modulation and anticancer activity. Despite the fact that these effects vary between individuals due to personal HGM richness, the information presented in this review contributes to understanding the effects of prebiotics and dietary fibers consumption on the generation of HGM metabolites and the mechanisms by which these metabolites interact with host cells improving host health.
Pichia pastoris (Komagataella phaffii) is a fast-growing methylotrophic yeast with the ability to assimilate several carbon sources such as methanol, glucose, or glycerol. It has been shown to have ...outstanding secretion capability with a variety of heterologous proteins. In previous studies, we engineered P. pastoris to co-express Escherichia coli AppA phytase and the HAC1 transcriptional activator using a bidirectional promoter. Phytase production was characterized in shake flasks and did not reflect industrial conditions. In the present study, phytase expression was explored and optimized using instrumented fermenters in continuous and fed-batch modes. First, the production of phytase was investigated under glucose de-repression in continuous culture at three dilution factors, 0.5 d
, 1 d
, and 1.5 d
. The fermenter parameters of these cultures were used to inform a kinetic model in batch and fed-batch modes for growth and phytase production. The kinetic model developed aided to design the glucose-feeding profile of a fed-batch culture. Kinetic model simulations under glucose de-repression and fed-batch conditions identified optimal phytase productivity at the specific growth rate of 0.041 h
. Validation of the model simulation with experimental data confirmed the feasibility of the model to predict phytase production in our newly engineered strain. Methanol was used only to induce the expression of phytase at high cell densities. Our results showed that high phytase production required two stages, the first stage used glucose under de-repression conditions to generate biomass while expressing phytase, and stage two used methanol to induce phytase expression. The production of phytase was improved 3.5-fold by methanol induction compared to the expression with glucose alone under de-repression conditions to a final phytase activity of 12.65 MU/L. This final volumetric phytase production represented an approximate 36-fold change compared to the flask fermentations. Finally, the phytase protein produced was assayed to confirm its molecular weight, and pH and temperature profiles. This study highlights the importance of optimizing protein production in P. pastoris when using novel promoters and presents a general approach to performing bioprocess optimization in this important production host.
Hydrogels are materials specially suited for encapsulation of biological elements. Their large water content provides an environment compatible with most biological molecules. Their crosslinked ...nature also provides an ideal material for the protection of encapsulated biological elements against degradation and/or immune recognition. This makes them attractive not only for controlled drug delivery of proteins, but they can also be used to encapsulate cells that can have therapeutic applications. Thus, hydrogels can be used to create systems that will deliver required therapies in a controlled manner by either encapsulation of proteins or even cells that produce molecules that will be released from these systems. Here, an overview of hydrogel encapsulation strategies of biological elements ranging from molecules to cells is discussed, with special emphasis on therapeutic applications.
Focal cortical dysplasias (FCDs) are malformations of cortical development that often result in medically refractory epilepsy, with a greater incidence in the pediatric population. The relationship ...between the disturbed cortical morphology and epileptogenic activity of FCDs remains unclear. We used the BCNU (carmustine 1-3-bis-chloroethyl-nitrosourea) animal model of cortical dysplasia to evaluate neuronal and laminar alterations and how these result in altered activity of intracortical networks in early life. We corroborated the previously reported morphological anomalies characteristic of the BCNU model, comprising slightly larger and rounder neurons and abnormal cortical lamination. Next, the neuronal activity of live cortical slices was evaluated through large field-of-view calcium imaging as well as the neuronal response to a stimulus that leads to cortical hyperexcitability (pilocarpine). Examination of the joint activity of neuronal calcium time series allowed us to identify intracortical communication patterns and their response to pilocarpine. The baseline power density distribution of neurons in the cortex of BCNU-treated animals was different from that of control animals, with the former showing no modulation after stimulus. Moreover, the intracortical communication pattern differed between the two groups, with cortexes from BCNU-treated animals displaying decreased inter-layer connectivity as compared to control animals. Our results indicate that the altered anatomical organization of the cortex of BCNU-treated rats translates into altered functional networks that respond abnormally to a hyperexcitable stimulus and highlight the role of network dysfunction in the pathophysiology of cortical dysplasia.
The formation of a hybrid metal−biopolymer material is described. The synthesis of this material consists of functionalizing the surface of gold nanoparticles through a series of steps that lead to ...epoxy-functionalized nanoparticles. These are subsequently reacted with hydroxyl moieties of the α-d-glucopyranosyl groups of dextran. Subsequently, the dextran chains are carboxylated through treatment with bromoacetic acid. The resultant material combines the unique optical properties of gold nanoparticles with the versatility that carboxylated dextran offers for further functionalization with biomolecules. The interaction of this material with three proteins was then investigated through changes in the plasmon resonance properties of the gold nanoparticles. Concanavalin A, a lectin that binds glucose and mannose by means of specific molecular recognition, interacts readily with this material and such interaction is easily detected using optical absorption spectroscopy. Through reaction of the carboxyl groups with (+)-biotinyl-3,6,9,-trioxaundecanediamine, a material bearing biotin groups was obtained. This could interact with streptavidin or antibiotin by means of specific molecular recognition. Further confirmation of biospecific interactions was obtained with control experiments in which the binding sites were blocked through preincubation of the proteins with the corresponding ligand in solution. Binding of these proteins was concentration-dependent over a wide concentration range. This material provides a simple and convenient colorimetric method for biospecific interaction analysis.
In this study, we assess the association between academics’ research agendas and their preferences for basic research, applied research, or experimental development. Using a sample of Mexican ...academics working in some of the country’s most research-oriented universities, we identify three clusters. The largest is composed of applied research-oriented academics, the second largest is composed of basic research-oriented academics, and the smallest is composed of academics who engage in both basic and applied research, and experimental development. The strategic research agendas of the three clusters are distinguished from each other along four main dimensions: Divergence, Discovery, Mentor Influence, and Social Orientation. These findings show that strategic research agendas are associated with preferences for basic research, applied research, or experimental development, but only to some extent. We also extend the Multi-Dimensional Research Agendas Inventory – Revised, a widely used instrument for measuring strategic research agendas, by adding a new dimension, “Government,” and validating the instrument in a new context. We also make the scale available in Spanish for use by academics, practitioners, managers, and administrators in Spanish-speaking countries.
More than three decades have passed since the publication of Lamendin et al.'s proposal in 1992. Over this time, numerous investigations have been conducted to assess the applicability of the ...technique in different populations with acceptable results in terms of estimation errors. The proposal by Lamendin and colleagues remains relevant today, and has made a significant contribution to adult age-at-death estimation due to its simplicity, repeatability, replicability, and high performance. Indeed, significant progress towards systematizing and strengthening the procedure has been reported in the published literature. One noteworthy advancement is the development of an international database that supports the use of Bayesian statistics for age-at-death estimation. This resource plays a crucial role in standardizing the methodology and improving the reliability for obtaining more reliable results on a global scale. The aim of this study is to investigate the historical evolution of the technique, to assess the accuracy of the results obtained by different analytic procedures, and to explore its impact in forensic applications through a systematic analysis of the specialized literature on this field. The current state of research indicates that this type of methodological research is an ongoing process, far from being completed. Many questions and challenges that require further attention to address effectively these issues remain unanswered, such as the development of non-linear regressions and probabilistic approaches, the deepening of procedures that improve global approximations, and the intensification of research focused on achieving more accurate estimations among individuals over 70 years-old. However, studies generally agree that the Lamendin technique works well for individuals between the ages of 30–60 years. It is still in force today, although the method has been significantly perfected. Despite the degree of research development in this area, further efforts are needed to improve the understanding and performance of these kinds of procedures. This will ultimately lead to an improvement in the accuracy and reliability of forensic investigation results worldwide.
•Lamendin technique is one of the most validated adult dental age estimation methods.•Research has shown an acceptable performance of the technique in age estimation.•Linear regression is the main statistical approach used for adult dental age estimation.•An openly website for age estimation through this technique was recently developed.
This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) ...bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73–94%) and color (90–94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ∼50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.
•This paper proposes a SAMBR operated with PAC for removing toxic azo dye byproducts.•PAC has acted as source of immobilized redox mediators increasing the color removal.•The SAMBR led to higher color (90–94%) and COD (73–94%) removal efficiencies.
Abstract There is significant interest in biomaterials that provide sustained release of therapeutic molecules to the retina. Poly( N -isopropylacrylamide) (PNIPAAm)-based materials have received ...significant attention as injectable drug delivery platforms due to PNIPAAm’s thermo-responsive properties at approximately 32 °C. While the drug delivery properties of PNIPAAm materials have been studied extensively, there is a need to evaluate the safety effects of hydrogel injection on retinal function. The purpose of this study was to examine the effect of poly(ethylene glycol) diacrylate (PEG-DA) crosslinked PNIPAAm hydrogel injection on retinal function. Utilizing scanning laser ophthalmoscopy (SLO), optical coherent tomography (OCT), and electroretinography (ERG), retinal function was assessed following hydrogel injection. In region near the hydrogel, there was a significant decrease in arterial and venous diameters (∼4%) and an increase in venous blood velocity (∼8%) 1 week post-injection. Retinal thickness decreased (∼6%) at 1 week and the maximum a- and b-wave amplitudes of ERG decreased (∼15%). All data returned to baseline values after week 1. These data suggest that the injection of PEG-DA crosslinked PNIPAAm hydrogel results in a small transient effect on retinal function without any long-term effects. These results further support the potential of PNIPAAm-based materials as an ocular drug delivery platform.
•This paper found EPS and SMP stratification at different heights of SAMBR.•The low amount of COD available in the upper SAMBR contributed to a high concentration of EPS in proximity of the ...membrane.•The EPS composition determined that LB-EPS and TB-EPS have a carbohydrate nature.•SMP stratification in the SAMBR was influenced by substrate complexity.•The main component of SMP was unknown SMP.
Membrane bioreactors (MBR) technology for wastewater offers many advantages over conventional technologies such as high effluent quality, less footprint and others. The main disadvantage of membrane bioreactors (MBR) is related to membrane fouling, which is mainly caused by extracellular polymeric substance (EPS) and soluble microbial products (SMP). This research studied EPS and SMP dynamics at different heights of a submerged anaerobic membrane bioreactor (SAMBR). The SAMBR was operated under two organic loading rates (OLR) (0.79 and 1.56kg/m3d) and was fed with synthetic wastewater with glucose as the carbon source. The results showed percentages of chemical oxygen demand (COD) removal above 95% and the highest COD removal rates were observed at the bottom of the reactor (>83%) for both OLR. The EPS showed a stratification with highest quantities in the supernatant. For the SMP the highest concentration was in the bottom of SAMBR where utilization predominated associated products whereas in the SAMBR supernatant predominated biomass associated products. The OLR change led to a significant increase in SMP accumulation but not in EPS. These facts showed that EPS and SMP dynamic in the SAMBR seemed to be mainly influenced by biological activity, total suspended solids concentration and substrate composition.
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