Postnatal characterization of cells in the accessory olfactory bulb of wild type and reeler mice

Olfaction is the most relevant chemosensory sense of the rodents. General odors are primarily detected by the main olfactory system while most pheromonal signals are received by the accessory olfactory system. The first relay in the brain occurs in the olfactory bulb, which is subdivided in the main and accessory olfactory bulb (MOB/AOB). Given that the cell generation time is different between AOB and MOB, and the cell characterization of AOB remains limited, the goal of this work was first, the definition of the layering of AOB/MOB and second, the determination of cellular phenotypes in the AOB in a time window corresponding to the early postnatal development. Moreover, since reelin (Reln) deficiency has been related to olfactory learning deficits, we analyzed reeler mice. First, we compared the layering between AOB and MOB at early embryonic stages. Then, cell phenotypes were established using specific neuronal and glial markers as well as the Reln adaptor protein Dab1 to analyse differences in both genetic backgrounds. There was no apparent difference in the cell phenotypes among AOB and MOB or between wild type (wt) and reeler animals. However, a disruption in the granular cell layer of reeler with respect to wt mice was observed. In conclusion, the AOB in Reln-deficient mice showed similar neuronal and glial cell types being only affected the organization of granular neurons

Protein-based emulsion electrosprayed micro- and submicroparticles for the encapsulation and stabilization of thermosensitive hydrophobic bioactives

This work shows the potential of emulsion electrospraying of proteins using food-grade emulsions for the microencapsulation and enhanced protection of a model thermosensitive hydrophobic bioactive. Specifically, gelatin, a whey protein concentrate (WPC) and a soy protein isolate (SPI) were compared as emulsion stabilizers and wall matrices for encapsulation of α-linolenic acid. In a preliminary stage, soy bean oil was used as the hydrophobic component for the implementation of the emulsion electrospraying process, investigating the effect of protein type and emulsion protocol used (i.e. with or without ultrasound treatment) on colloidal stability. This oil was then substituted by the ω-3 fatty acid and the emulsions were processed by electrospraying and spray-drying, comparing both techniques. While the latter resulted in massive bioactive degradation, electrospraying proved to be a suitable alternative, achieving microencapsulation efficiencies (MEE) of up to ∼70%. Although gelatin yielded low MEEs due to the need of employing acetic acid for its processing by electrospraying, SPI and WPC achieved MEEs over 60% for the non-sonicated emulsions. Moreover, the degradation of α-linolenic acid at 80 °C was significantly delayed when encapsulated within both matrices. Whilst less than an 8% of its alkene groups were detected after 27 h of thermal treatment for free α-linolenic acid, up to 43% and 67% still remained intact within the electrosprayed SPI and WPC capsules, respectively.Laura G. Gómez-Mascaraque is recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. The authors would like to thank the Spanish MINECO project AGL2012-30647 for financial support. Sara Díaz Cuesta is also acknowledged for experimental support.Peer reviewe

Stability and bioaccessibility of EGCG within edible micro-hydrogels. Chitosan vs. gelatin, a comparative study

Micro-hydrogels are very promising systems for the protection and controlled delivery of sensitive bioactives, but limited knowledge exists regarding the impact of this encapsulation on their bioaccessibility. In this work, two different hydrogel-forming biopolymers (gelatin and chitosan) were compared as wall materials for the microencapsulation of a model flavonoid, (−)-epigallocatechin gallate (EGCG). Results showed that gelatin was more adequate as wall material for the encapsulation of EGCG than chitosan, achieving higher encapsulation efficiencies (95% ± 6%), being more effective in delaying EGCG release and degradation in aqueous solution and exhibiting a 7 times higher bioaccessibility of the bioactive compound (in terms of antioxidant activity) after in-vitro gastrointestinal digestion. A very low bioaccessibility of EGCG in chitosan was observed, due to the neutralization of the carbohydrate in the basic simulating salivary conditions, thus precluding subsequent flavonoid release. Moreover, gelatin micro-hydrogels also hindered dimer formation during in-vitro digestion, thus suggesting greater bioavailability when compared with free EGCG.Laura G. Gómez-Mascaraque is recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. The authors would like to thank the Spanish MINECO projectAGL2015-63855-C2-1 for financial support.Peer reviewe

Impact of molecular weight on the formation of electrosprayed chitosan microcapsules as delivery vehicles for bioactive compounds

The molecular weight of chitosan is one of its most determinant characteristics, which affects its processability and its performance as a biomaterial. However, information about the effect of this parameter on the formation of electrosprayed chitosan microcapsules is scarce. In this work, the impact of chitosan molecular weight on its electrosprayability was studied and correlated with its effect on the viscosity, surface tension and electrical conductivity of solutions. A Discriminant Function Analysis revealed that the morphology of the electrosprayed chitosan materials could be correctly predicted using these three parameters for almost 85% of the samples. The suitability of using electrosprayed chitosan capsules as carriers for bioactive agents was also assessed by loading them with a model active compound, (−)-epigallocatechin gallate (EGCG). This encapsulation, with an estimated efficiency of around 80% in terms of preserved antioxidant activity, showed the potential to prolong the antiviral activity of EGCG against murine norovirus via gradual bioactive release combined with its protection against degradation in simulated physiological conditions.Laura G. Gómez-Mascaraque is recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. Gloria Sanchez was supported by the “Ramón y Cajal” Young Investigator Program. The authors would like to thank the Spanish MINECO project AGL2015-63855-C2-1 and INIA grant RTA2014-00024-C04-03 for financial support.Peer reviewe

Electrosprayed gelatin submicroparticles as edible carriers for the encapsulation of polyphenols of interest in functional foods

In this work, the potential of the electrospraying technique to obtain food-grade gelatin capsules in the submicron range for sensitive bioactive protection was explored, studying the influence of the protein concentration on the size and morphology of the obtained particles. Gelatin was selected as encapsulating material because, being commonly used as a food ingredient, it possesses unique gelation properties and is commercially available at a low cost. The electrosprayed matrices were used to encapsulate a model antioxidant molecule, (−)-epigallocatechin gallate (EGCG). Very high encapsulation efficiencies, close to 100%, were achieved, and the antioxidant activity of the bioactive was fully retained upon encapsulation. The EGCG release profiles showed a delayed release of the encapsulated antioxidant in aqueous solutions. Furthermore, while free EGCG in PBS lost a 30% of their antioxidant activity being completely degraded in 100 h, encapsulated EGCG retained its whole antioxidant activity within this time period.Laura G. Gómez-Mascaraque is recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. The authors would like to thank the Spanish MINECO project AGL2012-30647 for financial support.Peer reviewe

Dab1 (Disable Homolog-1) Reelin Adaptor Protein Is Overexpressed in the Olfactory Bulb at Early Postnatal Stages

Dab1 mediates reelin signalling and plays critical roles in early brain development such as the stereotypical positioning of neurons in the brain. The olfactory bulb undergoes a prominent layering reorganization, but shows not apparent differences between wild type and reeler in the layer organization. Therefore, an accurate regional and cellular simultaneous analysis of these molecules becomes essential to clarify the role played by Dab1 upon Reelin effect. The present study reveals a strong and consistent Dab1 mRNA and protein expressions, throughout the olfactory bulb layers in both wild type and reeler mice. In addition, noteworthy is the pattern of Dab1 location within cell nuclei in both strains. Furthermore, a temporal increment of Dab1 expression levels is detected from P0 to P15 in both strains, being the protein quantity higher in reeler than in wild type mice. Altogether, our results revealed that Reln acts directly from projection neurons via the production of different Reln fragments. Changes in the pattern of Dab1 expression could reflect an alternative Reln function in postnatal and adult stages, besides a possible regulation of Dab1 by other molecules distinct to Reln

Microencapsulation of a whey protein hydrolysate within micro-hydrogels: Impact on gastrointestinal stability and potential for functional yoghurt development

Gelatin and chitosan micro-hydrogels containing a potentially bioactive whey protein hydrolysate were developed through spray drying and the impact of microencapsulation on protection during digestion and peptide stability against lactic acid fermentation during yoghurt manufacturing was assessed. The results showed that the protection exerted by the encapsulation structures during milk fermentation was sequence- and matrix-dependent, being chitosan more effective than gelatin in stabilising the peptides. However, only 5 out of the 21 fermentation-susceptible peptides identified could be protected through encapsulation within chitosan (1 of which was also protected by gelatin). Moreover, the encapsulation within chitosan microparticles did not substantially affect the peptide profile of the digested hydrolysate, and therefore, the peptide bioaccessibility was not expected to be compromised.Laura G. Gómez-Mascaraque is the recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. The authors would like to thank the Spanish MINECO projects AGL2015-63855-C2-1 and AGL2015-66886-R for financial support.Peer reviewe

Optimization of electrospraying conditions for the microencapsulation of probiotics and evaluation of their resistance during storage and in-vitro digestion

Electrospraying has recently emerged as a novel microencapsulation technique with potential for the protection of probiotics. However, research efforts are still needed to minimize the viability loss observed during the processing of sensitive strains, and to maximize productivity. The aim of the present work was the optimization of the electrospraying conditions for the microencapsulation of a model probiotic microorganism, Lactobacillus plantarum, within a whey protein concentrate matrix. In a pre-optimization step, the convenience of encapsulating fresh culture instead of freeze-dried bacteria was established. Additionally, a surface response methodology was used to study the effect of the applied voltage, surfactant concentration, and addition of a prebiotic to the formulation on cell viability and productivity. Viability losses lower than 1 log10 CFU were achieved and the bacterial counts of the final products exceeded 8.5 log10 CFU/g. The protection ability of the developed structures during storage and in-vitro digestion was also evaluated.Laura G. Gómez-Mascaraque is recipient of a predoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO), Call 2013. Russell Cruz Morfin received a scholarship from the Mexican National Council for Science and Technology (CONACYT), Call 2014. Gloria Sánchez is supported by the “Ramón y Cajal” Young Investigator program of the MINECO. This work was financially supported by the Spanish MINECO project AGL2012-30647 and by the CSIC project 201470I002.Peer reviewe

Nano- and microstructural evolution of alginate beads in simulated gastrointestinal fluids. Impact of M/G ratio, molecular weight and pH

peer-reviewedAlginate microcapsules were prepared using three different alginate grades and incubated under simulated digestion conditions. Their micro- and nanostructural changes were studied using microscopy, laser diffraction and small angle X-ray scattering. Both the molecular weight and M/G ratio affected the size and nanostructural features of the capsules, but the changes in gastrointestinal conditions were mainly determined by the latter. All microcapsules swelled slightly in simulated gastric fluid (pH = 3) and swelled further in simulated intestinal fluid (pH = 7), particularly those with high mannuronic acid (M) contents. While high guluronic acid (G) beads maintained the nanostructural features characteristic of alginate gels (junction zones) in both media, these were rapidly disrupted in the M-rich capsules. Decreasing the pH of the gastric phase from 3 to 2 had dramatic structural impacts, resulting in a greater integrity of the microcapsules, thus highlighting the importance of the selected digestion protocol for rational microcapsule design

Assessment of the Thermal Behaviour of Rammed Earth Walls in the Summer Period

[EN] The constructive solutions characteristic of vernacular architecture are the result of the convergence of geographical, cultural and climatic factors that bring about constructions characterised by adaptation to their surroundings. However, at present, Spanish regulations do not contemplate the properties of traditional materials, such as those found in earthen constructions, whose great thermal inertia is ignored despite their thermal gains and compensations. Given these limitations, the purpose of this study is to assess the thermal behaviour of traditional earthen architecture adjusting to its real performance and original surroundings. This work thus examines a methodology to assess the thermal behaviour of rammed earth walls based on on-site data specifically collected in the summer in a case study located in La Serrania, a region in the northwest of the province of Valencia (Spain). The results show the evolution of exterior and interior surface temperatures of the earthen wall, quantifying its variation frequency and thermal energy transmission. Based on these data, the thermal transmittance of the wall is calculated and compared to highlight the difference from the normalised value, showing that a review of the Spanish regulations applied to earthen architecture is needed.This research was funded by the Spanish Ministry of Economy and Competitiveness as the work was part of the research project "Restoration and rehabilitation of traditional earthen architecture in the Iberian Peninsula. Guidelines and tools for a sustainable intervention" (Ref.: BIA2014-55924-R; main researchers: Camilla Mileto and Fernando Vegas Lopez-Manzanares)Balaguer-Garzón, L.; Vegas López-Manzanares, F.; Mileto, C.; García-Soriano, L. (2019). Assessment of the Thermal Behaviour of Rammed Earth Walls in the Summer Period. Sustainability. 11(7):1-12. https://doi.org/10.3390/su11071924S112117Código Técnico de la Edificación https://www.codigotecnico.orgMartínez-Molina, A., Tort-Ausina, I., Cho, S., & Vivancos, J.-L. (2016). Energy efficiency and thermal comfort in historic buildings: A review. Renewable and Sustainable Energy Reviews, 61, 70-85. doi:10.1016/j.rser.2016.03.018Webb, A. L. (2017). Energy retrofits in historic and traditional buildings: A review of problems and methods. Renewable and Sustainable Energy Reviews, 77, 748-759. doi:10.1016/j.rser.2017.01.145De Fino, M., Scioti, A., Cantatore, E., & Fatiguso, F. (2017). Methodological framework for assessment of energy behavior of historic towns in Mediterranean climate. Energy and Buildings, 144, 87-103. doi:10.1016/j.enbuild.2017.03.029Heathcote, K. (2011). El comportamiento térmico de los edificios de tierra. Informes de la Construcción, 63(523), 117-126. doi:10.3989/ic.10.024Balaguer, L., Mileto, C., Vegas López-Manzanares, F., & García-Soriano, L. (2019). Bioclimatic strategies of traditional earthen architecture. Journal of Cultural Heritage Management and Sustainable Development, 9(2), 227-246. doi:10.1108/jchmsd-07-2018-005