Functional characterisation and antimicrobial efficiency assessment of smart nanohydrogels containing natamycin incorporated into polysaccharide-based films

The potential application of polysaccharide-based films containing smart nanohydrogels for the controlled release of food preservatives is demonstrated here. Smart active packaging is the most promising alternative to traditional packaging as it provides a controlled antimicrobial effect, which allows reducing the amount of preservatives in the food bulk, releasing them only on demand. This work evaluates the usefulness of smart thermosensitive poly(N-isopropylacrylamide) (PNIPA) nanohydrogels with or without acrylic acid (AA) incorporated into polysaccharide-based films (GA) to transport natamycin and release it as a response to environmental triggers. Release kinetics in liquid medium from GA films containing PNIPA/AA nanohydrogels (GA-PNIPA(5) and GA-PNIPA-20AA(5)) presented a characteristic feature regarding the films without nanohydrogels that was the appearance of a lag time in natamycin release, able to reach values of around 35 h. Another important feature of natamycin release kinetics was the fact that the release from GA-PNIPA/AA films only occurred when temperature was increased, so that the natamycin release was restricted to when there is a risk of growth of microorganisms that cause food spoilage or the development of pathogenic microorganisms. Additionally, it could be observed that the relative fraction of natamycin released from GA-PNIPA/AA films was significantly (p<0.05) higher than that released from GA films loaded with the same amount of free natamycin. It can be hypothesised that the encapsulation of natamycin into nanohydrogels helped it to be released from GA films, creating reservoirs of natamycin into the films and, therefore, facilitating its diffusion through the film matrix when the nanohydrogel collapses. In a solid medium, the low water availability limited natamycin release from GA-PNIPA/AA films restricting the on/off release mechanism of PNIPA/AA nanohydrogels and favouring the hydrophobic interactions between natamycin and polymer chains at high temperatures. Despite the low natamycin release in solid media, antimicrobial efficiency of GA-PNIPA(5) films containing natamycin in acidified agar plates was higher than that obtained with GA films without natamycin and GA films with free natamycin, probably due to the protecting effect against degradation when natamycin was included in the nanohydrogels, allowing its release only when the temperature increased.Clara Fucinos and Miguel A. Cerqueira are recipients of a fellowship (SFRH/BPD/87910/2012 and SFRH/BPD/72753/2010, respectively) from the Fundacao para a Ciencia e Tecnologia (FCT, POPH-QREN, and FSE Portugal). The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013 and the project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes", Ref. NORTE-07-0124-FEDER-000028 co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER and the project from the "Ministerio de Educacion y Ciencia" (Spain) "Nanohidrogeles inteligentes sensibles a cambios de pH y Temperatura: Diseno, sintesis y aplicacion en terapia del cancer y el envasado activo de alimentos", Ref. MAT2010-21509-C03-01

Enhanced thylakoid photoprotection can increase yield and canopy radiation use efficiency in rice

High sunlight can raise plant growth rates but can potentially cause cellular damage. The likelihood of deleterious effects is lowered by a sophisticated set of photoprotective mechanisms, one of the most important being the controlled dissipation of energy from chlorophyll within photosystem II (PSII) measured as non-photochemical quenching (NPQ). Although ubiquitous, the role of NPQ in plant productivity remains uncertain because it momentarily reduces the quantum efficiency of photosynthesis. Here we used plants overexpressing the gene encoding a central regulator of NPQ, the protein PsbS, within a major crop species (rice) to assess the effect of photoprotection at the whole canopy scale. We accounted for canopy light interception, to our knowledge for the first time in this context. We show that in comparison to wild-type plants, psbS overexpressors increased canopy radiation use efficiency and grain yield in fluctuating light, demonstrating that photoprotective mechanisms should be altered to improve rice crop productivity

Improving phylogeny reconstruction at the strain level using peptidome datasets

Typical bacterial strain differentiation methods are often challenged by high genetic similarity between strains. To address this problem, we introduce a novel in silico peptide fingerprinting method based on conventional wet-lab protocols that enables the identification of potential strain-specific peptides. These can be further investigated using in vitro approaches, laying a foundation for the development of biomarker detection and application-specific methods. This novel method aims at reducing large amounts of comparative peptide data to binary matrices while maintaining a high phylogenetic resolution. The underlying case study concerns the Bacillus cereus group, namely the differentiation of Bacillus thuringiensis, Bacillus anthracis and Bacillus cereus strains. Results show that trees based on cytoplasmic and extracellular peptidomes are only marginally in conflict with those based on whole proteomes, as inferred by the established Genome-BLAST Distance Phylogeny (GBDP) method. Hence, these results indicate that the two approaches can most likely be used complementarily even in other organismal groups. The obtained results confirm previous reports about the misclassification of many strains within the B. cereus group. Moreover, our method was able to separate the B. anthracis strains with high resolution, similarly to the GBDP results as benchmarked via Bayesian inference and both Maximum Likelihood and Maximum Parsimony. In addition to the presented phylogenomic applications, whole-peptide fingerprinting might also become a valuable complementary technique to digital DNA-DNA hybridization, notably for bacterial classification at the species and subspecies level in the future.This research was funded by Grant AGL2013-44039-R from the Spanish “Plan Estatal de I+D+I”, and by Grant EM2014/046 from the “Plan Galego de investigación, innovación e crecemento 2011-2015”. BS was recipient of a Ramón y Cajal postdoctoral contractfrom the Spanish Ministry of Economyand Competitiveness. This work was also partially funded by the [14VI05] Contract-Programme from the University of Vigo and the Agrupamento INBIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273).The research leading to these results has also received funding from the European Union’s Seventh Framework Programme FP7/REGPOT-2012-2013.1 under grant agreement n˚ 316265, BIOCAPS. This document reflects only the authors’ views and the European Union is not liable for any use that may be made of the information contained herein. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

IoTFC: A Secure and Privacy Preserving Architecture for Smart Buildings

In the pursuit of cities to be more efficient and responsive, various kind of Internet of Things (IoT) devices, such as actuators and sensors are used. This paper focuses on one specific IoT application - the smart building, and investigates the security and privacy issues in an integrated IoT-fog-cloud (IoTFC) smart building architecture. We consider the surveillance, maintenance, environment, and concierge use cases for smart building, in terms of their characteristics, compatible communication technology, and security and privacy requirements. IoTFC provides a comprehensive solution to the security and privacy challenges of authentication, access control, anomaly detection, data privacy and location privacy. To the best of our knowledge, IoTFC is a novel architecture, as it combines a complete set of light-weight security and privacy solutions suitable for smart buildings

Evolution of quality of life and health‐related behaviors among Spanish university students

Summary At the beginning of their academic studies (testing phase), the quality of life and certain health‐related behaviors were evaluated. Four years later (retest phase), they were reevaluated. Between the two evaluation periods, a health promotion (HP) program was applied. The battery of instruments included measures: health‐related quality of life (HRQOL), alcoholic and nicotine dependence, eating habits, physical activity, and sexual behaviors. It also included a number of sociodemographic data. The results show that, in general, the students reported adequate levels of HRQOL, and there were no important differences between the two evaluation moments. Regarding dietary behavior, no significant changes were detected in the pattern of adherence to the Mediterranean diet, which remained at an average level of adequacy. On the contrary, significant decreases were detected in relation to alcohol and tobacco dependence as well as significant increases in physical activity levels. Lastly, with regard to sexual behavior, although certain aspects of improvement were perceived, there is a need to increase awareness of the systematic use of condoms. In conclusion, this study provides relevant information that will serve as a starting point for monitoring changes in health behaviors and for the design and implementation of HP actions directed at university studentsThis study was partially subsidized with funds from the Vice‐rectory of the Ourense Campus (University of Vigo) and by the Social Council of the University of Vigo., Grant/Award Number: Fiscal year 2016‐2017