Phase Relations in the Li2O-V2O3-V2O5 System at 700 C: Correlations with Magnetic Defect Concentration in Heavy Fermion LiV2O4

The phase relations in the Li2O-V2O3-V2O5 ternary system at 700 C for compositions in equilibrium with LiV2O4 are reported. This study clarified the synthesis conditions under which low and high magnetic defect concentrations can be obtained within the spinel structure of LiV2O4. We confirmed that the LiV2O4 phase can be obtained containing low (0.006 mol%) to high (0.83 mol%) magnetic defect concentrations n{defect} and with consistently high magnetic defect spin S values between 3 and 6.5. The high n{defect} values were obtained in the LiV2O4 phase in equilibrium with V2O3, Li3VO4, or LiVO2 and the low values in the LiV2O4 phase in equilibrium with V3O5. A model is suggested to explain this correlation.Comment: 6 pages, 7 figures; Phys. Rev. B (accepted

Grape must profiling and cultivar discrimination based on amino acid composition and general discriminant analysis with best subset

CITATION: Petrovic, G., Aleixandre-Tudo, J. L. & Buica, A. 2019. Grape must profiling and cultivar discrimination based on amino acid composition and general discriminant analysis with best subset. South African Journal of Enology and Viticulture, 40(2):10.21548/40-2-3373, doi:10.21548/40-2-3373.The original publication is available at http://www.journals.ac.za/index.php/sajevThe present study aimed to elucidate the amino acid profile of a number of grapevine cultivars relevant to the South African wine industry using 738 grape must samples obtained during the 2016 and 2017 harvests.  Proline and arginine were found to be the most abundant amino acids, with an average of 697.69 mg/L for proline (range 33.22-3445.43 mg/L) and 388.35 mg/L for arginine (range 13.56-1616.56 mg/L) across all vintages, regions, and cultivars. At the other extreme, ornithine (2.01 mg/L), glycine (3.28 mg/L), methionine (3.64 mg/L) and lysine (3.91 mg/L) were found to have the lowest concentrations, both in terms of the overall average, as well as per cultivar. Furthermore, the data were used to demonstrate how characteristic the amino acid profile is of a particular group (red or white) or cultivar. Cultivars were predicted based on their average amino acid concentrations using general discriminant analysis (GDA) and the best subset principle. For white musts, Chardonnay showed the highest prediction accuracy (100%), and Pinotage (75%) for red cultivars. Overall, the white cultivars included in this study were more accurately distinguished from one another (75.6%) compared to the red (60.1%). This predictive ability was subsequently compared to the accuracy of predicting cultivars based on only the arginine and proline concentrationsas well as the ratio between the two. The use of only these amino acids as well as the addition of the proline/arginine ratio as a predictor variable did not offer satisfactory discriminatory power between either white or red cultivars.https://www.journals.ac.za/index.php/sajev/article/view/3373Publisher's versio

Antimicrobial treatment improves mycobacterial survival in nonpermissive growth conditions

Antimicrobials targeting cell wall biosynthesis are generally considered inactive against nonreplicating bacteria. Paradoxically, we found that under nonpermissive growth conditions, exposure of Mycobacterium bovis BCG bacilli to such antimicrobials enhanced their survival. We identified a transcriptional regulator, RaaS (for regulator of antimicrobial-assisted survival), encoded by bcg1279 (rv1219c) as being responsible for the observed phenomenon. Induction of this transcriptional regulator resulted in reduced expression of specific ATP-dependent efflux pumps and promoted long-term survival of mycobacteria, while its deletion accelerated bacterial death under nonpermissive growth conditions in vitro and during macrophage or mouse infection. These findings have implications for the design of antimicrobial drug combination therapies for persistent infectious diseases, such as tuberculosis

Producción de sulfitos durante la fermentación de vinos blancos de Tardana y rosados y tintos de Tempranillo en la D.O. Utiel-Requena

[ES] En el presente trabajo se estudió la producción de sulfitos de diferentes cepas de levaduras comerciales durante la fermentación de vinos blancos, rosados y tintos. Para ello se realizó una experiencia con vinos blancos de la variedad `Tardana¿, y dos con vinos rosados y tintos de la variedad `Tempranillo¿. Se determinó el grado alcohólico, la acidez total, acidez volátil, pH, sulfuroso total, azúcares residuales, ácido málico, ácido láctico, ácido cítrico, y glicerol de los vinos, además de la intensidad colorante, el tono, la concentración de antocianos, y el índice de polifenoles totales en los vinos tintos. Los resultados obtenidos pusieron de manifiesto que la producción de sulfitos no superó valores medios de 1 mg/L, y que los valores de los parámetros analizados se encontraban dentro del rango de valores de los vinos de calidad. La fermentación se realizó con dos tipos de cepas de levaduras diferentes, observándose que la reinoculación a los 3 días del arranque de la fermentación daba origen al mínimo contenido de sulfitos.[EN] The production of sulphites during the fermentation of `Tardana¿ white wines, and `Tempranillo¿ rosé and red wines in the D.O. Utiel¿Requena. In the present work, the production of sulphites from different commercial yeast strains during the fermentation of white, rosé and red wines was studied. For this, an experience was carried out with white wines of the `Tardana¿ variety, and two with rosé and red wines of the `Tempranillo¿ variety. The alcoholic degree, total acidity, volatile acidity, pH, total sulphurous, residual sugars, malic acid, lactic acid, citric acid, and glycerol of the wines were determined, in addition to the colour intensity, the tone, the concentration of anthocyanins, and the total polyphenol index in red wines. The results obtained showed that the production of sulphites did not exceed average values of 1 mg/L, and that the values of the analysed parameters were within the range of values of quality wines. The fermentation was carried out with two different types of yeast strains, observing that the re¿inoculation 3 days after the start of the fermentation gave rise to the minimum content of sulphites.Martinez, J.; Xirivella, C.; Aleixandre Tudo, J.; Aleixandre Benavent, JL. (2020). Producción de sulfitos durante la fermentación de vinos blancos de Tardana y rosados y tintos de Tempranillo en la D.O. Utiel-Requena. Enoviticultura. 64:14-23. http://hdl.handle.net/10251/182182S14236

Understanding anti-tuberculosis drug efficacy: rethinking bacterial populations and how we model them

Tuberculosis still remains a global health emergency, claiming 1.5 million lives in 2013. The bacterium responsible for this disease, Mycobacterium tuberculosis (M.tb), has successfully survived within hostile host environments, adapting to immune defence mechanisms, for centuries. This has resulted in a disease that is challenging to treat, requiring lengthy chemotherapy with multi-drug regimens. One explanation for this difficulty in eliminating M.tb bacilli in vivo is the disparate action of antimicrobials on heterogeneous populations of M.tb, where mycobacterial physiological state may influence drug efficacy. In order to develop improved drug combinations that effectively target diverse mycobacterial phenotypes, it is important to understand how such subpopulations of M.tb are formed during human infection. We review here the in vitro and in vivo systems used to model M.tb subpopulations that may persist during drug therapy, and offer aspirations for future research in this field

Mycobacterium tuberculosis lineage 4 comprises globally distributed and geographically restricted sublineages

Generalist and specialist species differ in the breadth of their ecological niches. Little is known about the niche width of obligate human pathogens. Here we analyzed a global collection of Mycobacterium tuberculosis lineage 4 clinical isolates, the most geographically widespread cause of human tuberculosis. We show that lineage 4 comprises globally distributed and geographically restricted sublineages, suggesting a distinction between generalists and specialists. Population genomic analyses showed that, whereas the majority of human T cell epitopes were conserved in all sublineages, the proportion of variable epitopes was higher in generalists. Our data further support a European origin for the most common generalist sublineage. Hence, the global success of lineage 4 reflects distinct strategies adopted by different sublineages and the influence of human migration.We thank S. Lecher, S. Li and J. Zallet for technical support. Calculations were performed at the sciCORE scientific computing core facility at the University of Basel. This work was supported by the Swiss National Science Foundation (grants 310030_166687 (S.G.) and 320030_153442 (M.E.) and Swiss HIV Cohort Study grant 740 to L.F.), the European Research Council (309540-EVODRTB to S.G.), TB-PAN-NET (FP7-223681 to S.N.), PathoNgenTrace projects (FP7-278864-2 to S.N.), SystemsX.ch (S.G.), the German Center for Infection Research (DZIF; S.N.), the Novartis Foundation (S.G.), the Natural Science Foundation of China (91631301 to Q.G.), and the National Institute of Allergy and Infectious Diseases (5U01-AI069924-05) of the US National Institutes of Health (M.E.)

Additions of glutathione or specific glutathione-rich dry inactivated yeast preparation (DYP) to sauvignon blanc must : effect on wine chemical and sensory composition

CITATION: Gabrielli, M., et al. 2017. Additions of glutathione or specific glutathione-rich dry inactivated yeast preparation (DYP) to sauvignon blanc must : effect on wine chemical and sensory composition. South African Journal of Enology and Viticulture, 38(1):18-28, doi:10.21548/38-1-794.The original publication is available at http://www.journals.ac.za/index.php/sajevAlthough the addition of pure glutathione (GSH) is not allowed under current regulations, the concentration of this compound can be increased in wine through the addition of glutathione-enriched dry yeast preparations (DYP). These preparations have been observed to have antioxidant properties and could thus influence wine aroma and sensory characteristics. The main aim of this study was to investigate the effect of DYP and GSH juice additions on the sensory and chemical composition of Sauvignon blanc wine. Four juice additions were performed and compared against a control treatment: 5.5 mg/L of GSH; 0.4 g/L of DYP; 80 mg/L of GSH; 0.4 g/L of DYP plus 80 mg/L of GSH. After three months of bottling, the volatile and sensorial composition was investigated. The addition of DYP preparations to must increased the concentration of certain wine volatile compounds, with increased attributes of riper tropical fruit aromas, which was not always observed with the GSH additions. The addition of DYP influenced the concentrations of some volatile compounds, which modified the white wine aroma. The release of compounds other than GSH by the yeast products is proposed as the reason for these changes. The results observed in this study can assist winemakers to modify the aroma profile of Sauvignon blanc wines.http://www.journals.ac.za/index.php/sajev/article/view/794Publisher's versio