The efficient activity of plant essential oils for inhibiting Botrytis cinerea and Penicillium expansum: Mechanistic insights into antifungal activity

Botrytis cinerea and Penicillium expansum produce deterioration in fruit quality, causing losses to the food industry. Thus, plant essential oils (EOs) have been proposed as a sustainable alternative for minimizing the application of synthetic fungicides due to their broad-spectrum antifungal properties. This study investigated the efficacy of five EOs in suppressing the growth of B. cinerea and P. expansum and their potential antifungal mechanisms. EOs of Mentha × piperita L., Origanum vulgare L., Thymus vulgaris L., Eucalyptus globules Labill., and Lavandula angustifolia Mill., were screened for both fungi. The results showed that the EO of T. vulgaris and O. vulgare were the most efficient in inhibiting the growth of B. cinerea and P. expansum. The concentration increase of all EO tested increased fungi growth inhibition. Exposure of fungi to EOs of T. vulgaris and O. vulgare increased the pH and the release of constituents absorbing 260 nm and soluble proteins, reflecting membrane permeability alterations. Fluorescence microscopic examination revealed that tested EOs produce structural alteration in cell wall component deposition, decreasing the hypha width. Moreover, propidium iodide and Calcein-AM stains evidenced the loss of membrane integrity and reduced cell viability of fungi treated with EOs. Fungi treated with EOs decreased the mitochondria activity and the respiratory process. Therefore, these EOs are effective antifungal agents against B. cinerea and P. expansum, which is attributed to changes in the cell wall structure, the breakdown of the cell membrane, and the alteration of the mitochondrial activity.

Versión breve del Inventario de Perspectiva Temporal de Zimbardo para población chilena: Una comparación internacional

La perspectiva temporal ha sido un tema con un creciente interés en el mundo académico, debido a la relación que se ha establecido entre esta variable y elementos como bienestar subjetivo, autoestima, ansiedad, estrés, entre otras. El instrumento más utilizado para su medición, el Inventario de Perspectiva Temporal de Zimbardo (ZTPI), ha sido traducido y adaptado para su utilización en diversos países, incluyendo la construcción de versiones breves. El presente estudio propone una versión breve para la población chilena con una muestra de 829 personas (46.6 % hombres, edad media = 29.33 DE = 13.48), realizando una comparación con otras 6 versiones breves extranjeras disponibles. La versión propuesta cuenta con 15 ítems, 3 para cada uno de los 5 factores de la versión original. Se realizó un análisis factorial confirmatorio para comprobar la adecuación del modelo, obteniéndose un buen ajuste, similar a lo encontrado por otros estudios. Se plantea continuar estudiando y mejorando las propiedades psicométricas de esta versión, realzando la importancia de tener en cuenta las diferencias debido a factores culturales.

Iron-reducing bacteria decompose lignin by electron transfer from soil organic matter

Iron-reducing bacteria (IRB) are crucial for electron transfer in anaerobic soil microsites. The utilization of the energy gathered by this mechanism by decomposers of organic matter is a challenging and fascinating issue. We hypothesized that bacteria reducing Fe(III) (oxyhydr)oxides to soluble Fe(II) obtain electrons from reduced soil organic matter (SOM_r) involving lignin oxidation. Iron-reducing bacteria were isolated from topsoils of various climates (humid temperate, cold temperate, subpolar), vegetation types (mostly grasslands and forests), and derived from various parent materials treatments assigned as Granitic, Volcanic-allophanic, Fluvio-glacial, Basaltic-Antarctic and Metamorphic. After the screening of IRB by phospholipid fatty acid (PLFA) analysis and PCR identification (full-length 16S rDNA), the IRB were inoculated to 20 samples (five soils and 4 replicates) and a broad range of parallel processes were traced. Geobacter metallireducens and Geobacter lovleyi were the main Geobacteraceae-strains present in all soils and strongly increased the activity of ligninolytic enzymes: lignin peroxidase and manganese peroxidase. Carbon dioxide (CO₂) released from IRB-inoculated soils was 140% higher than that produced by Fenton reactions (induced by H₂O₂ and Fe(II) addition) but 40% lower than in non-sterile soils. CO₂ release was closely correlated with the produced Fe (II) and H₂O₂ consumption. The highest CO₂ was released from Basaltic-Antarctic soils with the highest Fe content and was closely correlated with lignin depolymerization (detection by fluorescence images). All IRB oxidized the lignin contained in the SOM within a wide pH range and in soils from all parent materials. We present a conceptual model showing electron shuttling from SOM containing lignin (as a C and energy source) to IRB to produce energy and promote Fe(III) (oxyhydr)oxides reduction was proposed and discussed.

Overtime expression of plasma membrane and mitochondrial function markers associated with cell death in human spermatozoa exposed to nonphysiological levels of reactive oxygen species

In many cell types, the potential of reactive oxygen species to induce death processes has been largely demonstrated. Studies in spermatozoa have associated the imbalance of reactive oxygen species and phosphatidylserine externalisation as an apoptosis marker. However, the lack of consensus about time effect in the joint expression of these and other death markers has made it difficult to understand the set of mechanisms influenced beyond the concentration effect of reactive oxygen species to stimulate cell death. Here, the plasma membrane permeability and integrity, phosphatidylserine externalisation and mitochondrial membrane potential were jointly evaluated as death markers in human spermatozoa stimulated with H₂ O₂ . The results showed a profound and sustained effect of dissipation in the mitochondrial membrane potential and an increased phosphatidylserine externalisation in human spermatozoa exposed to 3 mmol^-1 of H₂ O₂ at 30 min. This was followed by an increased membrane permeability after 45 min. The last observed event was the loss of cell membrane integrity at 60 min. In conclusion, mitochondria are rapidly affected in human spermatozoa exposed to reactive oxygen species, with the barely detectable mitochondrial membrane potential coexisting with the high phosphatidylserine externalisation in cells with normal membrane permeability.

Aristoteline, an Indole-Alkaloid, Induces Relaxation by Activating Potassium Channels and Blocking Calcium Channels in Isolated Rat Aorta

Alkaloids derived from plants have shown great medicinal benefits, and are often reported for their use in cardiovascular disease management. Aristotelia chilensis (Molina) Stuntz (Maqui) has shown important medicinal properties in traditional useage. In this study, we evaluated the effect of the indole-alkaloid aristoteline (ARI), isolated from leaves of Maqui, on vascular reactivity of isolated aortic rings from normotensive rats. ARI induced relaxation (100%) in a concentration-dependent manner in intact or denuded-endothelium aortic rings pre-contracted with phenylephrine (PE; 1 μM). However, a specific soluble guanylyl cyclase inhibitor (ODQ; 1 μM) significantly reduced the relaxation to ARI in aortic rings pre-contracted with PE. In the presence of ARI, the contraction induced by KCl or PE was significantly (p < 0.05) decreased. Interestingly, the potassium channel blockade with 10 μM BaCl₂ (Kir), 10 μM glibenclamide (K_ATP), 1 mM tetraethylammonium (TEA; KCa1.1), or 1 mM 4-aminopyridine (4-AP; Kv) significantly (p < 0.05) reduced the ARI-induced relaxation. ARI significantly (p < 0.05) reduced the contractile response to agonist of Ca_V1.2 channels (Bay K8644; 10 nM), likely reducing the influx of extracellular calcium through plasma membrane. The mechanisms associated with this process suggest an activation of the potassium channels, a calcium-induced antagonism and endothelium independent vasodilation that possibly involves the nitric oxide-independent soluble guanylate cyclase pathway.

Oil bodies as a potential microencapsulation carrier for astaxanthin stabilisation and safe delivery

Astaxanthin (AST) is a valued molecule because of its high antioxidant properties. However, AST is extremely sensitive to oxidation, causing the loss of its bioactive properties. The purposes of this study were to define conditions for microencapsulating AST in oil bodies (OB) from Brassica napus to enhance its oxidative stability, and to test the bioactivity of the microencapsulated AST (AST-M) in cells. Conditions for maximising microencapsulation efficiency (ME) were determined using the Response Surface Methodology, obtaining a high ME (>99%). OB loaded with AST showed a strong electrostatic repulsion in a wide range of pH and ionic strengths. It was found that AST-M exposed to air and light was more stable than free AST. In addition, the protective effect of AST against intracellular ROS production was positively influenced by microencapsulation in OB. These results suggest that OB offer a novel option for stabilising and delivering AST.

[Television publicity and food preferences of school age children of the metropolitan region]

BACKGROUND

There is an alarming increase in the prevalence of child obesity in Chile. Lack of exercise and bad feeding habits strongly strongly contribute to the problem.

AIM

To investigate the influence of television publicity on school age children food preferences.

MATERIAL AND METHODS

A semi structured interview was applied to a representative sample of 786 school age children aged 6 to 11 years old, living in Metropolitan Santiago. Time watching television during week days and the attitude towards food and beverage commercials was analyzed and related to food preferences.

RESULTS

Ninety nine percent of school age children watch television during week days and 20% watches more the three hours daily. Snack commercials such as those about potato chips, chocolates, cookies and ice cream, are preferred by 35% of children. Soda commercials are preferred by 33% and yoghurt commercials by 12%. Eighty five percent of children had money to buy food. Of these, 66% bought snacks, 15% bought sodas and 7% yoghurt. The same tendency was observed in school collations.

CONCLUSIONS

The high percentage of children, watching television and the influence of commercials in their food preferences, requires an urgent educational strategy to promote healthy feeding habits.

[Infant mortality in Chile: the great descent]

Infant mortality in Chile decreased from 120 to 12 per thousand between 1960 and 1994. Outstanding events of this "great descent" are reviewed, based on past research and on updated information. Demographic and socioeconomic changes and improvements in health care that occurred during this period of decline are shown. It is estimated that 30% of the reduction of infant mortality between 1972 and 1982 was due to the decreasing proportion of births of high mortality risk, as a consequence of the fertility decline initiated in the mid 60s. Possible explanations for the continuing decline of infant mortality during the economic crisis of 1975 and 1982 are discussed. Finally, neonatal and postneonatal mortality rates by causes are compared between 1994 and 1980 and causes of death in extreme groups of infant mortality differentials by age of mother, birth order, gestational age, place of residence and educational level of the mother are shown.