Identification and characterization of outer membrane vesicles from the fish pathogen Vibrio ordalii

Vibriosis outbreaks due to Vibrio ordalii occur globally, but Chilean salmon aquaculture, in particular, has suffered significant monetary losses in the last 15 years. Little is known about the virulence mechanisms employed by V. ordalii. However, most Vibrio pathogens (e.g., Vibrio anguillarum, a very close taxonomic species) present outer membrane vesicles (OMVs) that are released extracellularly and implicated in the delivery of virulence factors to host cells. This study provides the first reported evidence of the fish pathogen V. ordalii producing and releasing OMVs under normal growth conditions. Analyses were conducted with the V. ordalii strain Vo-LM-18 and the type strain ATCC 33509^T. For comparative purposes, the reference strain V. anguillarum ATCC 43307 was employed. The average size for the three Vibrio strains was 0.215 ± 0.6 µm (via scanning electron microscopy) or between 0.19 and 1.8 µm (via dynamic light scattering), with each bacterium presenting a wide range. SDS-PAGE revealed similarities in OMV patterns, but neither total nor external proteins were identical. Comparing V. ordalii ATCC 33509^T and Vo-LM-18, bands were most evident in the total proteins, and the greatest degree of similarity in OMV profiles was between 37 and 50 kDa. The purified OMVs demonstrated haemolytic enzyme activity, which could play a role during V. ordalii infection. These data represent an initial step towards gaining new insights into this virulence factor, of which a lot is known in other pathogenic microorganisms.     

Wood biochar produces different rates of root growth and transpiration in two maize hybrids (Zea mays L.) under drought stress

This study investigated the effects of wood-derived biochar (BC) applied at 1% to a C-poor silty-loam soil in the drought-tolerant (D24) and in the drought-sensitive (P1921) Pioneer Hi-Bred maize hybrids in pot and field trials (NE Italy). D24 had better growth than P1921 under rain-fed conditions without irrigation and soil amendment. The addition of biochar increased root growth in D24 (+38% root area) and decreases it in P1921 (?9%) at the silking stage, while the fraction of finer roots (<250 µm diam.) was reduced in D24 and increased in P1921. This led both hybrids to maintain the maximum transpiration at a lower fraction of transpirable soil water (from 82% to 45% in D24, and from 46% to 22% in P1921). There were no significant variations in plant nutrient contents, productivity and in the protein and starch contents of the grains, whereas the lipid content was reduced by biochar, particularly in P1921 (2.6% vs. 3% DW, ?13%).

We conclude that biochar can be profitably used to enhance drought tolerance in maize, possibly due to improvements in the physicochemical characteristics and the water content of treated soils, although maximum benefits are expected in drought-tolerant hybrids through increased root elongation and transpiration.     

Mapping vineyard vigor using airborne remote sensing: relations with yield,berry composition and sanitary status under humid climate conditions

Precision Agriculture - The aim of this study was to assess the spatial variability of plant vigor in a vineyard in a humid climate. Normalised Difference Vegetation Index (NDVI) was used for...     

Volatile emission after controlled atmosphere storage of Mondial Gala apples (Malus domestica): relationship to some involved enzyme activities

Mondial Gala apples were harvested at commercial maturity and stored at 1 degrees C under either air or controlled atmosphere (CA) conditions (2 kPa O2/2 kPa CO2 and 1 kPa O2/1 kPa CO2), where they remained for 3 or 6 months. Data on emission of selected volatile esters, alcohol precursors, and activity of some aroma-related enzymes in both peel and pulp tissues were obtained during subsequent shelf life of fruit and submitted to multivariate analysis procedures. CA storage caused a decrease in the emission of volatile esters in comparison to storage in air. Results suggest that lessened ester production was the consequence of modifications in activities of alcohol o-acyltransferase (AAT) and lipoxygenase (LOX) activities. For short-term storage, inhibition of lipoxygenase activity in CA stored fruit possibly led to a shortage of lipid-derived substrates, resulting in decreased production of volatile esters in spite of substantial ester-forming capacity that allowed for some recovery of fruit capacity for ester emission during the shelf life. For long-term storage, strong inhibition of AAT activity in CA stored fruit in combination with low LOX activities resulted in unrecoverable diminution of biosynthesis of volatile esters.     

Cold-storage potential of four yellow-fleshed peach cultivars defined by their volatile compounds emissions, standard quality parameters, and consumer acceptance

'Early Rich', 'Royal Glory', 'Sweet Dream(cov)', and 'Elegant Lady' peaches were stored at -0.5 °C for up to 40 days and then subjected to ripening at 20 °C for up to 3 days. Firmness, soluble solids content (SSC), titratable acidity (TA), color, consumer acceptance, and volatile compounds were then determined. The observed physicochemical changes included a significant decrease in firmness during both storage and commercialization periods. In contrast, the SSC, TA, and color remained constant during storage. Ten days of cold storage produced the highest total volatile emissions and the greatest consumer acceptance for 'Elegant Lady' and 'Sweet Dream(cov)', whereas similar results were obtained after 40 and 20 days for 'Royal Glory' and 'Early Rich', respectively. Volatile compounds that most consistently exhibited a positive correlation with consumer acceptance were dependent on the cultivar.     

First Web-Based Database on Total Phenolics and Oxygen Radical Absorbance Capacity (ORAC) of Fruits Produced and Consumed within the South Andes Region of South America

This paper reports the first database on antioxidants contained in fruits produced and consumed within the south Andes region of South America. The database ( www.portalantioxidantes.com ) contains over 500 total phenolics (TP) and ORAC values for more than 120 species/varieties of fruits. All analyses were conducted by a single ISO/IEC 17025-certified laboratory. The characterization comprised native berries such as maqui ( Aristotelia chilensis ), murtilla ( Ugni molinae ), and calafate ( Barberis microphylla ), which largely outscored all other studied fruits. Major differences in TP and ORAC were observed as a function of the fruit variety in berries, avocado, cherries, and apples. In fruits such as pears, apples, apricots, and peaches, a significant part of the TP and ORAC was accounted for by the antioxidants present in the peel. These data should be useful to estimate the fruit-based intake of TP and, through the ORAC data, their antioxidant-related contribution to the diet of south Andes populations.     

Growth,survival, body composition and amino acid profile of Macrobrachium borellii against the limitation of feeds with different C:N ratios with comments about application in integrated multi‐trophic aquaculture

One way to attain more sustainable aquaculture systems is through the species diversification and optimization of the feed input, such as obtained by integrated multi‐trophic aquaculture (IMTA). Macrobrachium borellii is a native freshwater prawn that reunites many useful features to be implemented in an IMTA. The aim of this study was to gather information about to which extent M. borellii can survive, grow and maintain body composition against feed limitation. The C:N ratios of feedstuffs were variable in order to simulate a hypothetical scenario of an integrated culture with fish of different trophic habits. The nutritional aspects (amino acid profile and proximal composition) of feeds and prawns were also analysed. Macrobrachium borellii could grow, survive and maintain the proximal content and C:N ratio of its muscle tissue with all feedstuffs but exhibited higher biomass gain and specific growth rate consuming feeds with lower C:N ratios. In this view, the integration of this prawn with omnivore or carnivore fish species should be recommended. The amino acid profile exhibited little variation before and after the experimental period, and was rich in lysine, leucine and arginine. In this study, it was also discussed the nutritional aspects of M. borelliii as a valuable by‐product to human and animal nutrition.