Reduction of gray mold development in table grapes by preharvest sprays with ethanol and calcium chloride

Preharvest applications of a 16% ethanol (EtOH) solution, containing 1% CaCl₂, reduced gray mold development in ‘Chasselas’ table grapes picked at a late harvest date. The losses due to rotten clusters dropped from 15% in controls to 5% in grapes treated with EtOH + CaCl₂. Over 6 weeks cold storage, the losses due to gray mold rots were reduced by 50% in EtOH + CaCl₂ treated clusters, compared to untreated controls. Preliminary experiments had shown that a 2% EtOH solution was already inducing a significant reduction in gray mold growth. A range of concentrations up to 50% ethanol had been tested in preliminary trials without observing damage to the vines and clusters. The treatments did not induce significant changes in fruit quality assessed by sensory analysis of healthy berries.     

Comparison of visual census and high definition video transects for monitoring coral reef fish assemblages

Monitoring fish and underwater habitats, particularly in and around marine protected areas (MPAs) requires non-destructive observation methods. This is generally achieved by divers conducting underwater visual censuses (UVC), but video-based techniques are now being used more often to observe underwater macrofauna and habitats. A comparison of these two techniques is relevant with the development of high-definition (HD) video, which constitutes a substantial improvement over previously available video resolutions at limited extra cost. We conducted a paired observation experiment involving both HD video and UVC in an MPA located in the New Caledonian lagoon, which is a highly diversified coral reef ecosystem. We compared three techniques for counting fish along 50 m × 4 m delineated strip transects: UVC and two video techniques in which the diver used either a straight trajectory (I-type transect) or a browsing one (S-type transect). The results showed that the proportion of fish that were not identified up to the species level did not exceed 3.3% in video observations versus 1.7% in UVC. The abundance and species richness were larger in UVC than in videos, and S-type transects detected more individuals and species than I-type transects. The average abundance and species richness observed by UVC were 1094 individuals and 69.7 species per transect respectively. In comparison with UVC, I-type and S-type video transects detected on average 56% and 61% of the abundance and 85% and 77% of the species richness seen by UVC respectively. Our results showed that, in comparison to UVC data recorded in situ, the post field analysis of HD video images provided representative observations of fish abundance and species diversity, although fewer species and individuals were detected.The advantages and shortcomings of each observation technique for monitoring fish assemblages, particularly in an MPA are discussed. HD video appears to be a cost-effective technique in terms of the human resources and time needed for field implementation. Overall, this study suggests that HD video-based techniques constitute an interesting complement to UVC, or an alternative when these cannot be implemented.     

Effect of glucocorticoid administration on adrenal gland size and sonographic appearance in beagle dogs

Our aim was to evaluate the influence of glucocorticoids on the adrenal gland using ultrasonography. Eleven healthy beagles were used in a prospective placebo-controlled study. All dogs received hydrocortisone at 10 mg/kg twice a day per os for 4 months or a gelatin capsule twice a day per os as a placebo. Clinical and endocrinologic examination of the dogs and ultrasonographic evaluation of adrenal echogenicity, shape, and measurement of the length and height of the cranial and caudal pole were performed at baseline (TO), at 1 (T1) and 4 months (T4) after the beginning of treatment, and 2 months after the end of the treatment including 1 month of tapering and 1 month without treatment (T6). The dogs were assigned randomly to the glucocorticoid (n = 6) and placebo groups (n = 5). At T1, the difference between the two groups for the height of the cranial and caudal pole was not ultrasonographically remarkable despite a statistically significant difference (P = 0.0165 and P = 0.0206). Decreased height and length of entire gland were observed at T4 (P < 0.0001, P = 0.0015, and P = 0.0035, respectively). Percentages of atrophy were variable between dogs. Both adrenal glands regained normal size and shape 1 month after cessation of glucocorticoid administration. As not all dogs developed marked adrenal gland atrophy and the degree of atrophy varied widely between individuals, ultrasonography cannot be the technique of choice to detect iatrogenic hypercortisolism. Ultrasonographic changes are reversible within 1 month after the end of glucocorticoid administration.     

Feeding flaxseed in grass hay and barley silage diets to beef cows increases alpha-linolenic acid and its biohydrogenation intermediates in subcutaneous fat

The objective of the study was to determine temporal fat deposition and fatty acid profiles in beef cows fed hay- or barley silage-based diets, with or without flaxseed. Crossbred cull beef cows (n = 64, >30 mo of age, 620 ± 5 kg) were removed from grassland pastures, randomly assigned to 16 pens, and given ad libitum access to 50:50 (wt/wt, DM basis) forage:concentrate diets containing 0 or 15% ground flaxseed (DM basis, 5.2% added fat). Diets consisted of hay control (HC), hay+flaxseed (HF), barley silage control (SC), and silage+flaxseed (SF). Backfat biopsies were obtained from each cow at 0, 6, and 12 wk, and at slaughter (~20 wk) to assess fatty acid composition. With the exception of feed efficiency, flaxseed × forage interactions were not significant for backfat accumulation or performance parameters. Flaxseed improved (P < 0.01) feed conversion when supplemented to hay-based diet and increased ADG (P = 0.03), resulting in a heavier (P = 0.02) BW. Compared with hay, barley silage increased (P < 0.01) DMI, ADG, and feed efficiency. Subcutaneous fat contained 0.68% n-3 fatty acids at wk 0, and reached 0.68, 0.81, and 0.94% in HF cows after 6, 12, and 20 wk, respectively (Y(n-3) = 0.0133X + 0.6491, r = 0.87). It was 0.67% at wk 0, and reached 0.65, 0.77, and 0.90% in SF cows after 6, 12, and 20 wk, respectively (Y(n-3) = 0.0121X + 0.6349, r = 0.75). In contrast, weight percentage of n-3 fatty acids decreased in HC cows from 0.63, 0.50, and 0.47, to 0.43%, and in SC cows from 0.63, 0.40, and 0.36, to 0.33% over the 20 wk. A forage × flaxseed interaction (P < 0.05) occurred for many of the α-linolenic acid (ALA) biohydrogenation intermediates, including vaccenic acid (C18:1 trans-11) and CLA (combined C18:2 trans-7,cis-9 and cis-9,trans-11) in plasma, and in subcutaneous fat this also included non-CLA dienes. Concentrations of most α-linolenic acid biohydrogenation intermediates were greater when feeding flaxseed with hay. In conclusion, forage source altered plasma concentrations and rate of accumulation of ALA biohydrogenation products in subcutaneous fat from beef cows fed flaxseed. Factors responsible for this response are yet to be defined, but may include forage-mediated changes in ruminal biohydrogenation of ALA, as well as alterations in fatty acid metabolism and deposition.     

Formation of micella containing solubilized sterols during rehydration of active dry yeasts improves their fermenting capacity

During their rehydration in aqueous media, active dry yeasts (ADY) may be supplemented with inactive yeasts, yeast derivatives, or other optional complementary nutrients to improve their fermentation capacity. We found that yeast sterols solubilized in situ during ADY rehydration were particularly efficient for stimulating the fermenting capacity of ADY. Spontaneous solubilization of sterols during rehydration occurred by the formation of micelles by membrane phospholipids and specific cell wall polysaccharides and sterols, both compounds being provided by inactive dry yeasts (IDY). These micelles contained a specific distribution of the initial sterols from the inactive yeasts. Above a concentration of 100 mg L(-1) in the rehydration medium, these micelles acted as emulsifiers. Their critical micellar concentration (cmc) was found to be about 4 g L(-1). During rehydration, purified micelles, at a concentration near the cmc, were able to interact quickly with yeast cell membranes by modifying the yeast plasma membrane order [monitored by steady-state fluorescence anisotropy of 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene-p-toluenesulfonate (TMA-DPH) probe] and by increasing the sterol contents of ADY. Such an enrichment of ADY by very low concentrations of solubilized sterols was very efficient for the completion of fermentations. This is useful when musts are limited in available phytosterols or when micro-oxygenation is not desirable during fermentation.     

Effect of macerating enzymes on the oligosaccharide profiles of Merlot red wines

Commercial pectinase preparations are applied in winemaking to improve wine processing and final quality. These preparations contain pectolytic enzyme activities such as polygalacturonases, pectin esterases, pectin lyases, and rhamnogalacturonases. These enzymes modify the polysaccharide and oligosaccharide composition of wines. The influence of various commercial enzyme preparations on wine oligosaccharide composition was studied, on Merlot wines from the Bordeaux area. Wine oligosaccharides were isolated by high-resolution size-exclusion chromatography on a Superdex-30 HR column. The glycosyl residue and glycosyl linkage compositions of the oligosaccharide fractions obtained were determined. The MS spectra of the Merlot oligosaccharide fractions from control and enzyme-treated wines were recorded on an AccuTOF mass spectrometer equipped with an electrospray ionization (ESI) source and a time-of-flight (TOF) mass analyzer. Oligosaccharides in the control wines were partly methylated homogalacturonans, corresponding to smooth regions of pectins, whereas those of the enzyme-treated wines were mostly rhamnogalacturonan-like structures linked with neutral lateral chains, arising from the hairy regions. The enzyme preparations used thus cleaved the rhamnogalacturonan backbone of the hairy zones and demethylated and hydrolyzed the smooth regions. Besides, different structures were detected, depending on the enzyme preparation used, indicating that they contained rhamnogalacturonase activities with different specificities. The oligosaccharide profiles can serve as a marker of enzymatic treatments.     

Steady state pig dendritic cells migrating in skin draining pseudo-afferent lymph are semi-mature

Dendritic cells (DC) in peripheral tissues are considered as immature cells that mature and migrate towards lymph nodes upon stimulation with pathogens. This commonly accepted paradigm is challenged by the fact that tolerance to peripheral self antigen is controlled by mature DC and that DC collected from afferent lymph draining different tissues from several species, in the absence of pathogen signaling, were inconsistently found to be either at a mature or semi-mature state. In order to better define the maturation state of DC that migrate in lymph in absence of pathogen stimulation, we compared skin lymph DC to resident and LPS (lipopolysaccharide)-activated skin DC thanks to the establishment of a mini-pig model of lymph duct cannulation. Based on their co-stimulatory molecules expression and endocytotic capacities, pig lymph skin DC were found at an intermediate state of maturation between resident and LPS-activated skin DC and were fully capable of allogeneic T cell stimulation. Furthermore, lymph skin DC could be further matured by LPS or influenza stimulation. Thus, using the pig skin model which is relevant to human, we show that skin-derived DC constantly migrate at an intermediate state of maturation that can be further enhanced upon appropriate stimulation.     

Symbioses of Cyanobacteria in Marine Environments: Ecological Insights and Biotechnological Perspectives

Cyanobacteria are a diversified phylum of nitrogen-fixing, photo-oxygenic bacteria able to colonize a wide array of environments. In addition to their fundamental role as diazotrophs, they produce a plethora of bioactive molecules, often as secondary metabolites, exhibiting various biological and ecological functions to be further investigated. Among all the identified species, cyanobacteria are capable to embrace symbiotic relationships in marine environments with organisms such as protozoans, macroalgae, seagrasses, and sponges, up to ascidians and other invertebrates. These symbioses have been demonstrated to dramatically change the cyanobacteria physiology, inducing the production of usually unexpressed bioactive molecules. Indeed, metabolic changes in cyanobacteria engaged in a symbiotic relationship are triggered by an exchange of infochemicals and activate silenced pathways. Drug discovery studies demonstrated that those molecules have interesting biotechnological perspectives. In this review, we explore the cyanobacterial symbioses in marine environments, considering them not only as diazotrophs but taking into consideration exchanges of infochemicals as well and emphasizing both the chemical ecology of relationship and the candidate biotechnological value for pharmaceutical and nutraceutical applications.