Encapsulation of combi-cleas of glycosidases in alginate beads and polyvinyl alcohol for wine aroma enhancement

The aromatic expression of wines can be enhanced by the addition of specific glycosidases, although their poor stability remains a limitation. Coimmobilization of glycosidases as cross-linked enzyme aggregates (combi-CLEAs) offers a simple solution yielding highly stable biocatalysts. Nevertheless, the small particle size of combi-CLEAs hinders their recovery, preventing their industrial application. Encapsulation of combi-CLEAs of glycosidases in alginate beads and in polyvinyl alcohol is proposed as a solution. Combi-CLEAS of β-D-glucosidase and α-L-arabinofuranosidase were prepared and encapsulated. The effects of combi-CLEA loading and particle size on the expressed specific activity (IU/g) of the biocatalysts were evaluated. Best results were obtained with 2.6 mm diameter polyvinyl alcohol particles at a loading of 60 mg/g, exhibiting activities of 1.9 and 1.0 IU/g for β-D-glucosidase and α-L-arabinofuranosidase, respectively. Afterwards, the stability of the biocatalysts was tested in white wine. All the encapsulated biocatalysts retained full activity after 140 incubation days, outperforming both free enzymes and nonencapsulated combi-CLEAs. Nevertheless, the alginate-encapsulated biocatalysts showed a brittle consistency, making recovery unfeasible. Conversely, the polyvinyl-encapsulated biocatalyst remained intact throughout the assay. The encapsulation of combi-CLEAs in polyvinyl alcohol proved to be a simple methodology that allows their recovery and reuse to harness their full catalytic potential

Knowledge and behaviors regarding salt intake in Mozambique

Background/objectives: Health education and regulatory measures may contribute to lower population salt intake. Therefore, we aimed to describe knowledge and behaviors related to salt intake in Mozambique. Subjects/methods: A cross-sectional evaluation of a representative sample of the population aged 15–64 years (n = 3116) was conducted in 2014/2015, following the Stepwise Approach to Chronic Disease Risk Factor Surveillance, including a 12-question module for evaluation of dietary salt. Results: Three dimensions were identified in the questionnaire, named “self-reported salt intake”, “knowledge of health effects of salt intake”, and “behaviors for control of salt intake”. A total of 7.4% of the participants perceived that they consumed too much/far too much salt and 25.9% reported adding salt/salty seasoning often/always to prepared foods. The proportion considering that it was not important to decrease the salt contents of their diet was 8%, and 16.9% were not aware that high salt intake could be deleterious for health. Prevalences of lack of behaviors for reducing salt intake ranged from 74.9% for not limiting consumption of processed foods, to 95% for not buying low salt alternatives. There were few differences according to socio-demographic variables, but awareness of hypertension was, in general, associated with better knowledge and less frequent behaviors likely to contribute to a high salt intake. Conclusions: Most Mozambicans were aware that high salt intake can cause health problems, but the self-reported salt intake and behaviors for its control show an ample margin for improvement. This study provides evidence to guide population level salt-reducing policies

Development of a Hybrid Bioinorganic Nanobiocatalyst: Remarkable Impact of the Immobilization Conditions on Activity and Stability of β-Galactosidase

Hybrid bioinorganic biocatalysts have received much attention due to their simple synthesis, high efficiency, and structural features that favor enzyme activity and stability. The present work introduces a biomineralization strategy for the formation of hybrid nanocrystals from β-galactosidase. The effects of the immobilization conditions were studied, identifying the important effect of metal ions and pH on the immobilization yield and the recovered activity. For a deeper understanding of the biomineralization process, an in silico study was carried out to identify the ion binding sites at the different conditions. The selected β-galactosidase nanocrystals showed high specific activity (35,000 IU/g biocatalyst) and remarkable thermal stability with a half-life 11 times higher than the soluble enzyme. The nanobiocatalyst was successfully tested for the synthesis of galacto-oligosaccharides, achieving an outstanding performance, showing no signs of diffusional limitations. Thus, a new, simple, biocompatible and inexpensive nanobiocatalyst was produced with high enzyme recovery (82%), exhibiting high specific activity and high stability, with promising industrial applications

Study of the ichthyotoxic microalga Heterosigma akashiwo by transcriptional activation of sublethal marker Hsp70b in Transwell co-culture assays.

Despite the advance of knowledge about the factors and potential mechanisms triggering the ichthyotoxicity in microalgae, these remain unclear or are controversial for several species (e.g. Heterosigma). Neither typical toxicity tests carried out with cell extracts nor direct exposure to harmful species were proved suitable to unravel the mechanism of harm. Ichthyotoxic species show a complex harmful effect on fish, which is mediated through various mechanisms depending on the species. In this work, we present a method to study sub-lethal effects triggered by reactive oxygen species of a population of harmful algae in vivo over a fish cell line. To that end, Transwell co-cultures in which causative and target species are separated by a 0.4 μm pore membrane were carried out. This allowed the evaluation of the effect of the released molecules by cells in a rapid and compact test. In our method, the harmful effect was sensed through the transcriptional activation of sub-lethal marker Hsp70b in the CHSE214 salmon cell line. The method was tested with the raphidophyte Heterosigma akashiwo and Dunaliella tertiolecta (as negative control). It was shown that superoxide intracellular content and its release are not linked in these species. The methodology allowed proving that reactive oxygen species produced by H. akashiwo are able to induce the transcriptional activation of sub-lethal marker Hsp70b. However, neither loss of viability nor apoptosis was observed in CHSE214 salmon cell line except when exposed to direct contact with the raphidophyte cells (or their extract). Consequently, ROS was not concluded to be the main cause of ichthyotoxicity in H. akashiwo

Effect in the expression of SOD and Catalase in CHSE-214 cells exposed to <i>H</i>. <i>akashiwo</i> microalga (CCMP302).

<p>Effect in the expression of SOD and Catalase in CHSE-214 cells exposed to <i>H</i>. <i>akashiwo</i> microalga (CCMP302).</p

Study of the ichthyotoxic microalga <i>Heterosigma akashiwo</i> by transcriptional activation of sublethal marker Hsp70b in Transwell co-culture assays - Fig 1

<p>Relative Hsp70b mRNA expression in CHSE-214 cells exposed to <i>H</i>. <i>akashiwo</i> (CCMP302) (10,000 cell/mL) for 6 h in the exponential (A) and stationary (B) growth phases. Data were relativized to Transwell exposure to <i>D</i>. <i>tertiolecta</i>.</p

Relative Hsp70b mRNA expression in CHSE-214 cells in <i>Transwell</i> co-culture with to <i>H</i>. <i>akashiwo</i> (CCMP302 and CCMP2425) (10,000 cell/mL) for 30 min in the exponential and stationary growth phases.

<p>Data were relativized to unexposed CHSE-214 cells.</p

ROS-associated fluorescence emission of <i>H</i>. <i>akashiwo</i> (CCMP302 and CCMP2425) cells and <i>D</i>. <i>tertiolecta</i> cells in exponential and stationary phases, after incubation with H₂DCFDA for different cell concentrations.

<p>ROS-associated fluorescence emission of <i>H</i>. <i>akashiwo</i> (CCMP302 and CCMP2425) cells and <i>D</i>. <i>tertiolecta</i> cells in exponential and stationary phases, after incubation with H₂DCFDA for different cell concentrations.</p

Study of the ichthyotoxic microalga <i>Heterosigma akashiwo</i> by transcriptional activation of sublethal marker Hsp70b in Transwell co-culture assays - Fig 4

<p>Quantitative determinations of intracellular (A) and extracellular (B) superoxide in <i>H</i>. <i>akashiwo</i> (CCMP302 and CCMP2425) and <i>D</i>. <i>tertiolecta</i> as a non-ichthyotoxic control.</p