The Antarctic yeast Candida sake: Understanding cold metabolism impact on wine.

Current winemaking trends include low-temperature fermentations and using non-Saccharomyces yeasts as the most promising tools to produce lower alcohol and increased aromatic complexity wines. Here we explored the oenological attributes of a C. sake strain, H14Cs, isolated in the sub-Antarctic region. As expected, the cold sea water yeast strain showed greater cold growth, Na+-toxicity resistance and freeze tolerance than the S. cerevisiae QA23 strain, which we used as a commercial wine yeast control. C. sake H14Cs was found to be more sensitive to ethanol. The fermentation trials of low-sugar content must demonstrated that C. sake H14Cs allowed the cold-induced lag phase of growth to be eliminated and also notably reduced the ethanol (-30%) and glycerol (-50%) content in wine. Instead C. sake produced sorbitol as a compatible osmolyte. Finally, the inspection of the main wine volatile compounds revealed that C. sake produced more higher alcohols than S. cerevisiae. In conclusion, our work evidences that using the Antarctic C. sake H14Cs yeast improves low-temperature must fermentations and has the potential to provide a wine with less ethanol and also particular attributes.

Past and Future of Non-Saccharomyces Yeasts: From Spoilage Microorganisms to Biotechnological Tools for Improving Wine Aroma Complexity.

It is well established that non-Saccharomyces wine yeasts, considered in the past as undesired or spoilage yeasts, can enhance the analytical composition, and aroma profile of the wine. The contribution of non-Saccharomyces yeasts, including the ability to secret enzymes and produce secondary metabolites, glycerol and ethanol, release of mannoproteins or contributions to color stability, is species- and strain-specific, pointing out the key importance of a clever strain selection. The use of mixed starters of selected non-Saccharomyces yeasts with strains of Saccharomyces cerevisiae represents an alternative to both spontaneous and inoculated wine fermentations, taking advantage of the potential positive role that non-Saccharomyces wine yeast species play in the organoleptic characteristics of wine. In this context mixed starters can meet the growing demand for new and improved wine yeast strains adapted to different types and styles of wine. With the aim of presenting old and new evidences on the potential of non-Saccharomyces yeasts to address this market trend, we mainly review the studies focused on non-Saccharomyces strain selection and design of mixed starters directed to improve primary and secondary aroma of wines. The ability of non-Saccharomyces wine yeasts to produce enzymes and metabolites of oenological relevance is also discussed.

Increasing the levels of 2-phenylethyl acetate in wine through the use of a mixed culture of Hanseniaspora osmophila and Saccharomyces cerevisiae.

The impact of mixed cultures of Hanseniaspora osmophila and Saccharomyces cerevisiae with different initial yeast ratios on wine composition has been examined. The mixed culture significantly affected sugar consumption, the main enological parameters and ester concentrations, with the exception of glycerol, isoamyl acetate and diethyl succinate levels. Remarkably, in wines obtained with mixed cultures the concentration of 2-phenylethyl acetate was approximately 3- to 9-fold greater than that produced by S. cerevisiae pure culture. Moreover sensory evaluation revealed a stronger fruity character in wines fermented with mixed cultures than in control wines. Independently of the mixed culture used, all wines showed concentrations of acetic acid and ethyl acetate within the ranges described for wines. Our data suggest that a mixed culture of H. osmophila and S. cerevisiae can be used as a tool to increase 2-phenylethyl acetate in wine and that its concentration can be controlled by modulating the initial yeast ratio in the culture.

Rational selection of non-Saccharomyces wine yeasts for mixed starters based on ester formation and enological traits.

Thirty-eight yeast strains belonging to the genera Candida, Hanseniaspora, Pichia, Torulaspora and Zygosaccharomyces were screened for ester formation on synthetic microbiological medium. The genera Hanseniaspora and Pichia stood out as the best acetate ester producers. Based on the ester profile Hanseniaspora guilliermondii 11027 and 11102, Hanseniaspora osmophila 1471 and Pichia membranifaciens 10113 and 10550 were selected for further characterization of enological traits. When growing on must H. osmophila 1471, which displayed a glucophilic nature and was able to consume more than 90% of initial must sugars, produced levels of acetic acid, medium chain fatty acids and ethyl acetate, within the ranges described for wine. On the other hand, it was found to be a strong producer of 2-phenylethyl acetate. Our data suggest that H. osmophila 1471 is a good candidate for mixed starters, although the possible interactions with S. cerevisiae deserve further research.

The meridian incision: a technical modification in the conservative surgery of the impacted maxillary canine.

We describe a technical modification of the apical repositioning flap in the conservative surgical treatment of the impacted canine in buccal position. This amendment improves the tooth's eventual visualization, thus permitting a better evolutive follow-up of its eruption process and, most importantly, providing the tooth with buccal attached gingiva that will accompany it in its downward progression, procuring a cervical contour without retraction, a satisfactory esthetic outcome and a physiologically correct periodontal ridge. The traditional apical repositioning flap also bestows the canine with attached gingiva; however, since the flap is sutured apically and its width is significantly smaller than the remaining surgical defect, the wound's closure is compromised at one of its edges and often requires healing by second intention at an undesired location next to the buccal sulcus. We believe the introduction of the meridian incision is a simple, expedient technical modification with efficient results.

The meridian incision: A technical modification in the conservative surgery of the impacted maxillary canine

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We describe a technical modification of the apical repositioning flap in the conservative surgical treatment of the impacted canine in buccal position. This amendment improves the tooth’s eventual visualization, thus permitting a better evolutive follow-up of its eruption process and, most importantly, providing the tooth with buccal attached gingiva that will accompany it in its downward progression, procuring a cervical contour without retraction, a satisfactory esthetic outcome and a physiologically correct periodontal ridge.The traditional apical repositioning flap also bestows the canine with attached gingiva; however, since the flap is sutured apically and its width is significantly smaller than the remaining surgical defect, the wound’s closure is compromised at one of its edges and often requires healing by second intention at an undesired location next to the buccal sulcus. We believe the introduction of the meridian incision is a simple, expedient technical modification with efficientresults

Dietary phytoestrogens improve stroke outcome after transient focal cerebral ischemia in rats.

As phytoestrogens are postulated as being neuroprotectants, we assessed the hypothesis that dietary isoflavone-type phytoestrogens are neuroprotective against ischemic stroke. Transient focal cerebral ischemia (90 min) was induced by middle cerebral artery occlusion (MCAO) following the intraluminal thread technique, both in rats fed with soy-based diet and in rats fed with isoflavone-free diet. Cerebro-cortical laser-Doppler flow (cortical perfusion, CP), arterial blood pressure, core temperature, PaO2, PaCO2, pH and glycemia were measured before, during and after MCAO. Neurological examination and infarct volume measurements were carried out 3 days after the ischemic insult. Dietary isoflavones (both glycosides and aglycones) were measured by high-performance liquid chromatography. Neither pre-ischemic, intra-ischemic nor post-ischemic CP values were significantly different between the soy-based diet and the isoflavone-free diet groups. Animals fed with the soy-based diet showed an infarct volume of 122 +/- 20.2 mm3 (19 +/- 3.3% of the whole ipsilateral hemisphere volume). In animals fed with the isoflavone-free diet the mean infarct volume was significantly higher, 191 +/- 26.7 mm3 (28 +/- 4.1%, P < 0.05). Neurological examination revealed significantly higher impairment in the isoflavone-free diet group compared with the soy-based diet group (3.3 +/- 0.5 vs. 1.9 +/- 0.5, P < 0.05). These results demonstrate that dietary isoflavones improve stroke outcome after transient focal cerebral ischemia in such a way that a higher dietary isoflavone content results in a lower infarct volume and a better neurological status.

Over-production of the major exoglucanase of Saccharomyces cerevisiae leads to an increase in the aroma of wine.

A Saccharomyces cerevisiae wine strain over-producing an endogenous exoglucanase encoded by the EXG1 gene has been constructed to investigate the possible role of this enzyme in increasing wine aroma through the release of a glycosidic precursor. Purification and biochemical characterization of the EXG1 protein has been performed revealing an apparent molecular mass of 61 kDa and an optimal pH and temperature of 4-5 and 55 degrees C, respectively. No activity loss due to ethanol, SO2, glucose or fructose at concentrations typically found in wine and must has been detected. The production of exoglucanase activity by two wine yeast strain transformants in which the expression of EXG1 was driven by either the S. cerevisiae actin or EXG1 gene promoters has been monitored in culture medium and in grape must during the fermentation process. Various alcohols and terpenes were enhanced in the aroma profiles of wines produced by inoculation with the exoglucanase over-expressing yeasts, though the transformant strain carrying EXG1 under the control of the actin promoter yielded higher levels of free volatiles in wine.

Férula quirúrgica intermedia en cirugía ortognática bimaxilar: Un método simple de obtención / The intermediate surgical splint in bimaxillary surgery. A simple method for obtaining it

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Pharmacological profile of phytoestrogens in cerebral vessels: in vitro study with rabbit basilar artery.

As a previous step to consider their use in the pharmacology for stroke, we investigated the effects of four phytoestrogens (i.e. genistein, daidzein, zearalanone and biochanin A) on cerebral vessels. Cerebral vascular responses were analyzed by conventional recording of isometric tension in rabbit basilar artery segments kept in organ bath under standard conditions. The four phytoestrogens elicited concentration-dependent relaxant responses of different potency in basilar artery segments previously contracted with either 5x10(-2) M KCl or 10(-4) M UTP. Neither endothelium removal, 10(-4) M N(omega)-nitro-L-arginine methyl ester (L-NAME, nitric oxide (NO) synthase inhibitor), 10(-5) M1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, selective inhibitor of NO-sensitive guanylyl cyclase), 10(-5) M 4H-8-bromo-1,2,4-oxadiazolo(3,4-d)benz(b)(1,4)oxazin-1-one (NS2028, specific soluble guanylyl cyclase inhibitor), nor 10(-5) M indomethacin (prostaglandin biosynthesis inhibitor) modified the phytoestrogen-elicited vasorelaxant responses. On the other hand, Ca(2+)-elicited contractile responses were effectively inhibited in the presence of phytoestrogens. Phytoestrogens act as cerebrovascular relaxants by a mechanism which involves Ca(2+) entry blockade in the vascular smooth muscle rather than stimulation of vasorelaxant endothelium-related mechanisms such as NO/cGMP or prostaglandins.

Acetate ester formation in wine by mixed cultures in laboratory fermentations.

Two non-Saccharomyces wine yeast strains, Hanseniaspora guilliermondii 11104 and Pichia anomala 10590, selected as good producers of acetate esters when grown on synthetic microbiological medium, have been tested in wine fermentations as mixed cultures together with Saccharomyces cerevisiae. Wines produced using mixed cultures showed levels of acetaldehyde, acetic acid, glycerol and total higher alcohols within the ranges described for wine, whereas an increase in acetate ester concentrations was found. Ethyl acetate was the main ester produced, and isoamyl acetate and 2-phenylethyl acetate made up the next largest group of ester compounds in the wines analysed. H. guilliermondii 11104 was found to be a strong producer of 2-phenylethyl acetate in both pure and mixed cultures whereas S. cerevisiae was the best producer of ethyl esters. Mixed cultures did not influence ethyl ester levels at all.