3D (x-y-t) Raman imaging of tomato fruit cuticle: Microchemistry during development.

The cuticle is a protective extracellular matrix that covers the above-ground epidermis of land plants. Here, we studied the cuticle of tomato (Solanum lycopersicum L.) fruits in situ using confocal Raman microscopy. Microsections from cuticles isolated at different developmental stages were scanned to visualize cuticle components with a spatial resolution of 342 nm by univariate and multivariate data analysis. Three main components, cutin, polysaccharides, and aromatics, were identified, with the latter exhibiting the strongest Raman scattering intensity. Phenolic acids and flavonoids were differentiated within the cuticle, and three schematic cuticle models were identified during development. Phenolic acids were found across the entire cuticle at the earliest stage of development, i.e. during the formation of the procuticle layer. Based on a mixture analysis with reference component spectra, the phenolic acids were identified as mainly esterified p-coumaric acid together with free p-hydroxybenzoic acid. During the cell expansion period of growth, phenolic acids accumulated in an outermost layer of the cuticle and in the middle region of the pegs. In these stages of development, cellulose and pectin were detected next to the inner cuticle region, close to the epidermal cell where flavonoid impregnation started during ripening. In the first ripening stage, chalconaringenin was observed, while methoxylated chalcones were chosen by the algorithm to fit the mature cuticle spectra. The colocation of carbohydrates, esterified p-coumaric acid, and methoxylated chalconaringenin suggests that the latter two link polysaccharide and cutin domains. Elucidating the different distribution of aromatics within the cuticle, suggests important functions: (1) overall impregnation conferring mechanical and thermal functions (2) the outermost phenolic acid layer displaying UV-B protection of the plant tissue.

Synergic photoprotection of phenolic compounds present in tomato fruit cuticle: a spectroscopic investigation in solution.

Coumaric acids and flavonoids play pivotal roles in protecting plants against ultraviolet radiation (UVR) exposure. In this work, we focus our photoprotection studies on p-coumaric acid and the flavonoid naringenin chalcone. Photoprotection is well-understood in p-coumaric acid; in contrast, information surrounding photoprotection in naringenin chalcone is lacking. Additionally, and vitally, how these two species work in unison to provide photoprotection across the UV-B and UV-A is unknown. Herein, we employ transient absorption spectroscopy together with steady-state irradiation studies to unravel the photoprotection mechanism of a solution of p-coumaric acid and naringenin chalcone. We find that the excited state dynamics of p-coumaric acid are significantly altered in the presence of naringenin chalcone. This finding concurs with quenching of the p-coumaric acid fluorescence with increasing concentration of naringenin chalcone. We propose a Förster energy transfer mechanism is operative via the formation of dipole-dipole interactions between p-coumaric acid and naringenin chalcone. To our knowledge, this is the first demonstration in plants of a synergic effect between two classes of phenolics to bypass the potentially damaging effects of UVR.

Structure, isomerization and dimerization processes of naringenin flavonoids.

In this study, the theoretical and experimental results on the molecular structure and reactivity of the plant flavonoids naringenin chalcone and naringenin are reported. UV-vis and Raman spectra were recorded and their main bands have been assigned theoretically. Moreover, the analysis of the naringenin chalcone-naringenin cyclization-isomerization reaction and the formation of homodimers and heterodimers have been performed within a DFT framework. The presence of H-bonded water networks is mandatory to make the cyclization energetically suitable, suggesting that this equilibrium will occur in an aqueous intracellular environment rather than in the extracellular and hydrophobic plant cuticles. Additionally, the preferential formation of homodimers stabilized by π-π stacking that will interact with other dimers by H-bonding over the formation of naringenin chalcone-naringenin heterodimers is also proposed in a hydrophobic environment. These results give a plausible model to explain how flavonoids are located within the cuticle molecular arrangement.

Radiationless mechanism of UV deactivation by cuticle phenolics in plants.

Hydroxycinnamic acids present in plant cuticles, the interphase and the main protective barrier between the plant and the environment, exhibit singular photochemical properties that could allow them to act as a UV shield. Here, we employ transient absorption spectroscopy on isolated cuticles and leaf epidermises to study in situ the photodynamics of these molecules in the excited state. Based on quantum chemical calculations on p-coumaric acid, the main phenolic acid present in the cuticle, we propose a model in which cuticle phenolics display a photoprotective mechanism based in an ultrafast and non-radiative excited state deactivation combined with fluorescence emission. As such, the cuticle can be regarded as the first and foremost protective barrier against UV radiation. This photostable and photodynamic mechanism seems to be universal in land plants giving a special role and function to the presence of different aromatic domains in plant cuticles and epidermises.

COVID-19 Course in Allergic Asthma Patients: A Spanish Cohort Analysis.

PURPOSE: The acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has had a high impact on patients with chronic diseases. In the literature, there are different perspectives on asthma as comorbidity or risk factor on COVID-19 severity. PATIENTS AND METHODS: The aim of this retrospective study across 13 allergy departments in Spain was to determine the severity of COVID-19 in asthmatic adults followed in allergy departments and its relationship with atopy, clinical and demographic characteristics, phenotypes and laboratory data. In addition, lung function test and asthma control test (ACT) before and after COVID-19 were analyzed. Data was obtained from electronic medical records from March 2020 to April 2021. RESULTS: Two hundred one asthmatic patients were diagnosed with COVID-19 infection by validated detection test. About 30% of the patients were admitted for bilateral pneumonia. Advanced age, elevated D-dimer, lower numbers of lymphocytes and eosinophils, heart diseases and hypertension were associated with severe COVID-19. Allergic and mixed allergic/eosinophilic phenotype and their biomarkers (total IgE, aeroallergens sensitizations, allergic rhinitis, and blood eosinophilia) were related to fewer hospital admissions. Poor control and lower forced expiratory volume in the first second (FEV1) were related to worse prognosis of COVID-19. CONCLUSION: Asthmatic patients with allergic and eosinophilic phenotype have a better evolution of COVID-19 and lower risk of admissions. Older patients, cardiovascular comorbidities, AERD and eosinopenia are related to severity COVID-19.

The Response of Tomato Fruit Cuticle Membranes Against Heat and Light.

Two important biophysical properties, the thermal and UV-Vis screening capacity, of isolated tomato fruit cuticle membranes (CM) have been studied by differential scanning calorimetry (DSC) and UV-Vis spectrometry, respectively. A first order melting, corresponding to waxes, and a second order glass transition (T g ) thermal events have been observed. The glass transition was less defined and displaced toward higher temperatures along the fruit ripening. In immature and mature green fruits, the CM was always in the viscous and more fluid state but, in ripe fruits, daily and seasonal temperature fluctuations may cause the transition between the glassy and viscous states altering the mass transfer between the epidermal plant cells and the environment. CM dewaxing reduced the T g value, as derived from the role of waxes as fillers. T g reduction was more intense after polysaccharide removal due to their highly interwoven distribution within the cutin matrix that restricts the chain mobility. Such effect was amplified by the presence of phenolic compounds in ripe cuticle membranes. The structural rigidity induced by phenolics in tomato CMs was directly reflected in their mechanical elastic modulus. The heat capacity (Cp rev ) of cuticle membranes was found to depend on the developmental stage of the fruits and was higher in immature and green stages. The average Cp rev value was above the one of air, which confers heat regulation capacity to CM. Cuticle membranes screened the UV-B light by 99% irrespectively the developmental stage of the fruit. As intra and epicuticular waxes contributed very little to the UV screening, this protection capacity is attributed to the absorption by cinnamic acid derivatives. However, the blocking capacity toward UV-A is mainly due to the CM thickness increment during growth and to the absorption by flavone chalconaringenin accumulated during ripening. The build-up of phenolic compounds was found to be an efficient mechanism to regulate both the thermal and UV screening properties of cuticle membranes.

Pectin-cellulose nanocrystal biocomposites: Tuning of physical properties and biodegradability.

The fabrication of pectin-cellulose nanocrystal (CNC) biocomposites has been systematically investigated by blending both polysaccharides at different relative concentrations. Circular free-standing films with a diameter of 9 cm were prepared by simple solution of these carbohydrates in water followed by drop-casting and solvent evaporation. The addition of pectin allows to finely tune the properties of the biocomposites. Textural characterization by AFM showed fibrous morphology and an increase in fiber diameter with pectin content. XRD analysis demonstrated that pectin incorporation also reduced the degree of crystallinity though no specific interaction between both polysaccharides was detected, by ATR-FTIR spectroscopy. The optical properties of these biocomposites were characterized for the first time and it was found that pectin in the blend reduced the reflectance of visible light and increased UV absorbance. Thermal stability, analyzed by TGA, was improved with the incorporation of pectin. Finally, pectin-cellulose nanocrystal biocomposites showed a good biodegradability in seawater, comparable to other common bioplastics such as cellulose and low-molecular weight polylactide, among others.

Insoluble and Thermostable Polyhydroxyesters From a Renewable Natural Occurring Polyhydroxylated Fatty Acid.

To explore the potential of long chain polyhydroxyalkanoates as non-toxic food packaging materials, the characterization of polyesters prepared from a natural occurring polyhydroxylated C16 carboxylic acid (9,10,16-trihydroxyhexadecanoic or aleuritic acid) has been addressed. Such monomer has been selected to elucidate the reactivity of primary and secondary hydroxyl groups and their contribution to the structure and properties of the polyester. Resulting polyaleuritate films have been produced using an open mold in one-step, solvent-free self-polycondensation in melt state and directly in air to evaluate the effect of oxygen in their final physical and chemical properties. These polymers are amorphous, insoluble, and thermostable, being therefore suitable for solvent, and heat resistant barrier materials. Structurally, most of primary hydroxyls are involved in ester bonds, but there is some branching arising from the partial participation of secondary O-H groups. The oxidative cleavage of the vicinal diol moiety and a subsequent secondary esterification had a noticeable effect on the amorphization and stiffening of the polyester by branching and densification of the ester bond network. A derivation of such structural modification was the surface compaction and the reduction of permeability to water molecules. The addition of Ti(OiPr)4 as a catalyst had a moderate effect, likely because of a poor diffusion within the melt, but noticeably accelerated both the secondary esterification and the oxidative processes. Primary esterification was a high conversion bulk reaction while oxidation and secondary esterification was restricted to nearby regions of the air exposed side of cast films. The reason was a progressive hindering of oxygen diffusion as the reaction progresses and a self-regulation of the altered layer growth. Despite such a reduced extent, the oxidized layer noticeably increased the UV-vis light blockage capacity. In general, characterized physical properties suggest a high potential of these polyaleuritate polyesters as food preserving materials.

Mutación en el gen SCN9Aasociado con el síndrome de Dravet: presentación de un caso pediátrico / Mutation in the SCN9A Gene Associated with Dravet Syndrome: A Pediatric Case Report / Mutação no gene SCN9A associada à síndrome de Dravet: relato de um caso pediátrico

Introducción:el síndrome de Dravet, también conocido como epilepsia mioclónica grave de la infancia, corresponde a una encefalopatía epiléptica resistente a fármacos que inicia generalmente en el primer año de vida. Se caracteriza por crisis epilépticas que suelen tener múltiples desencadenantes; el más asociado es la presencia de episodios febriles previos. Se considera una enfermedad rara, debido a su baja incidencia y prevalencia. Presentación del caso: niño de 10 años de edad con un cuadro de epilepsia de origen estructural, asociada con un retraso en el neurodesarrollo y anomalías craneofaciales meno-res, con antecedente de cardiopatía congénita no corregida, colpocefalia y agenesia del cuerpo calloso. Debido a la persistencia de las crisis convulsivas y su consiguiente resistencia farmacológica, se le rea-lizó un exoma genético que evidenció una mutación del gen SCN9. Discusión: el síndrome de Dravet debe ser sospechado en todo paciente menor de un año que tenga crisis convulsivas a repetición asociadas con episodios febriles cuantificados. Aproximadamente, entre el 70 % y el 85 % de los pacientes con el diagnóstico de síndrome de Dravet presenta una mutación en el gen SCN1A, por lo que mutaciones en otros genes que codifican para canales de sodio, ubicados en el mismo cromosoma, como el SCN9A, podrían contribuir de forma multifactorial a dicha entidad

Introduction: Dravet syndrome, also known as severe myoclonic epilepsy in infancy, is a drug resistant epileptic encephalopathy that usually begins in the first year of life. It is characterized by the presence of epileptic seizures that usually have multiple triggers; the most currently associated is the presence of previous febrile episodes. It is considered as a rare disease due to its low incidence and prevalence. Case presentation: We reported the case of a ten-year-old boy with structural epilepsy associated with a neuro-developmental delay and minor craniofacial anomalies. He had a history of uncorrected congenital heart disease, colpocephaly, and agenesis of the corpus callosum. Due to the persistence of seizures secondary to drug resistance, it was decided to perform a genetic exome that evidenced a mutation of the SCN9A gene. Conclusions: Dravet syndrome should be suspected in all patients under one year of age who have recu-rrent seizures associated with fever that does not respond to medication and modifies its presentation. Approximately 70%−85% of the patients diagnosed with Dravet syndrome have a mutation in the SCN1A gene; therefore, mutations in other genes that encode sodium channels located on the same chromosome, such as SCN9A, could contribute in a multifactorial way.

Introdução: a síndrome de Dravet, também conhecida como epilepsia mioclônica grave da infância, corresponde a uma encefalopatia epiléptica resistente a medicamentos que geralmente se inicia no primeiro ano de vida. É caracterizada pela presença de crises epilépticas que costumam ter múltiplos detonantes, sendo que o mais associado atualmente é a presença de episódios febris prévios. É conside-rada uma doença rara devido à sua baixa incidência e prevalência. Apresentação do caso: é apresentado o caso de um menino de 10 anos de idade com quadro de epilepsia de origem estrutural, associada a atraso no desenvolvimento neurológico e pequenas anomalias craniofaciais; com histórico de cardio-patia congênita não corrigida, colpocefalia e agenesia do corpo caloso. Devido à persistência das crises epilépticas e consequente resistência farmacológica, optou-se pela realização de um exoma genético que apresenta uma mutação do gene SCN9. Discussão: a síndrome de Dravet deve ser suspeitada em todos os pacientes com menos de um ano de idade que apresentam convulsões repetidas associadas a episódios febris quantificados. Aproximadamente 70 a 85% dos pacientes com diagnóstico de síndrome de Dravet apresentam mutação no gene SCN1A, portanto mutações em outros genes que codificam canais de sódio, localizados no mesmo cromossomo, como o SCN9A, poderiam contribuir de forma multifatorial para essa entidade