A mathematical model of the link between growth and L-malic acid consumption for five strains of Oenococcus oeni

In winemaking, after the alcoholic fermentation of red wines and some white wines, L-malic acid must be converted into L-lactic acid to reduce the acidity. This malolactic fermentation (MLF) is usually carried out by the lactic acid bacteria Oenococcus oeni. Depending on the level of process control, selected O. oeni is inoculated or the natural microbiota of the cellar is used. This study considers the link between growth and MLF for five strains of O. oeni species. The kinetics of growth and L-malic acid consumption were followed in modified MRS medium (20 °C, pH 3.5, and 10 % ethanol) in anaerobic conditions. A large variability was found among the strains for both their growth and their consumption of L-malic acid. There was no direct link between biomass productivities and consumption of L-malic acid among strains but there was a link of proportionality between the specific growth of a strain and its specific consumption of L-malic acid. Experiments with and without malic acid clearly demonstrated that malic acid consumption improved the growth of strains. This link was quantified by a mathematical model comparing the intrinsic malic acid consumption capacity of the strains

J-PLUS: The Javalambre Photometric Local Universe Survey

The Javalambre Photometric Local Universe Survey (J-PLUS) is an ongoing 12-band photometric optical survey, observing thousands of square degrees of the Northern Hemisphere from the dedicated JAST/T80 telescope at the Observatorio Astrofisico de Javalambre (OAJ). The T80Cam is a camera with a field of view of 2 deg(2) mounted on a telescope with a diameter of 83 cm, and is equipped with a unique system of filters spanning the entire optical range (3500-10 000 angstrom). This filter system is a combination of broad-, medium-, and narrow-band filters, optimally designed to extract the rest-frame spectral features (the 3700-4000 angstrom Balmer break region, H delta, Ca H+K, the G band, and the Mg b and Ca triplets) that are key to characterizing stellar types and delivering a low-resolution photospectrum for each pixel of the observed sky. With a typical depth of AB similar to 21.25 mag per band, this filter set thus allows for an unbiased and accurate characterization of the stellar population in our Galaxy, it provides an unprecedented 2D photospectral information for all resolved galaxies in the local Universe, as well as accurate photo-z estimates (at the delta z/(1 + z) similar to 0.005-0.03 precision level) for moderately bright (up to r similar to 20 mag) extragalactic sources. While some narrow-band filters are designed for the study of particular emission features ([O II]/lambda 3727, H alpha/lambda 6563) up to z < 0.017, they also provide well-defined windows for the analysis of other emission lines at higher redshifts. As a result, J-PLUS has the potential to contribute to a wide range of fields in Astrophysics, both in the nearby Universe (Milky Way structure, globular clusters, 2D IFU-like studies, stellar populations of nearby and moderate-redshift galaxies, clusters of galaxies) and at high redshifts (emission-line galaxies at z approximate to 0.77, 2.2, and 4.4, quasi-stellar objects, etc.). With this paper, we release the first similar to 1000 deg(2) of J-PLUS data, containing about 4.3 million stars and 3.0 million galaxies at r < 21 mag. With a goal of 8500 deg(2) for the total J-PLUS footprint, these numbers are expected to rise to about 35 million stars and 24 million galaxies by the end of the survey

Deficiency of Nrf2 accelerates the effector phase of arthritis and aggravates joint disease

Contains fulltext : 97785.pdf (publisher's version ) (Open Access)AIMS: Although oxidative stress participates in the etiopathogenesis of rheumatoid arthritis, its importance in this inflammatory disease has not been fully elucidated. In this study, we analyzed the relevance of the transcription factor Nrf2, master regulator of redox homeostasis, in the effector phase of an animal model of rheumatoid arthritis, using the transfer of serum from K/BxN transgenic mice to Nrf2(-/-) mice. RESULTS: Nrf2 deficiency accelerated the incidence of arthritis, and animals showed a widespread disease affecting both front and hind paws. Therefore, the inflammatory response was enhanced, with increased migration of leukocytes and joint destruction in front paws. We observed an increased production of tumor necrosis factor-alpha, interleukin-6, and CXCL-1 in the joint, with small changes in eicosanoid levels. Serum levels of CXCL-1 and receptor activator for nuclear factor kappaB ligand were enhanced and osteocalcin decreased in arthritic Nrf2(-/-) mice. The expression of cyclooxygenase-2, inducible nitric oxide synthase, and peroxynitrite in the joints was higher in Nrf2 deficiency, whereas heme oxygenase-1 was downregulated. Innovation: Nrf2 may be a therapeutic target for arthritis. CONCLUSION: Our results support a protective role of Nrf2 against joint inflammation and degeneration in arthritis

Estimating consumer lock-in effects from firm-level data

This paper proposes a practical method for estimating consumer lock-in effects from firm-level data. The method compares the behavior of already contracted consumers to the behavior of new consumers, the latter serving as a counterfactual to the former. In panel regressions on firms' incoming and quitting consumers, we look at the differential response to price changes and identify the lock-in effect from the difference between the two. We discuss the potential econometric issues and measurement problems and offer solutions to them. We illustrate our method by analyzing the market for personal loans in Hungary and find strong lock-in effects. © 2012 Springer Science+Business Media New York

Isolation and characterization of Oenococcus oeni from Aglianico wines.

A technological characterization of Oenococcus oeni strains isolated from Aglianico wines was performed to select starter cultures for malolactic fermentation (MLF). One hundred and fifty six O. oeni isolates were extracted from Aglianico wines, and identified by using speciesspecific PCR. Malolactic activity (MLA), sulphur dioxide (SO2) resistance, acetaldehyde metabolism and other technological characteristics were tested. Differences in the technologically relevant characteristics were observed. All O. oeni strains were able to grow at low temperature and none in presence of 14% of ethanol. About 80% of O. oeni degraded more than 80% of acetaldehyde, producing ethanol and acetic acid as final products. Among nine O. oeni chosen, four isolates were sensitive to 60 mg of SO2 l-1, while the other five had high resistance. Considering their technological characteristics, five O. oeni strains could be selected starter cultures for MLF in Aglianico

Validation of the use of multiple internal control genes, and the application of real-time quantitative PCR, to study esterase gene expression in Oenococcus oeni

The study of gene expression and accurate quantitation of target genes in any organism depends on correct normalisation. Due to the increase in studies on Oenococcus oeni gene expression, there is a clear need for alternative reference genes in order to reliably measure expression levels. In this manuscript, we propose the approach of using multiple reference genes to provide a more robust basis for establishing a reference gene set. The identification and evaluation of a panel of nine reference genes, including the commonly used ldhD, for real-time PCR normalisation was performed in O. oeni. Expression levels of these reference genes were then measured by real-time qPCR in an independent set of O. oeni samples (n = 30). The nine genes were ranked according to their stability of gene expression measure (M) using geNorm to identify the most consistently expressed reference genes. This approach resulted in the identification of multiple reference genes that may be used for a screening and more robust normalisation of target gene expression measured by real-time RT-qPCR. Expression of esterase genes was then measured in these O. oeni samples in the presence of known esterase substrates. The results give an indication of how these genes may be involved in ester synthesis and hydrolysis in O. oeni.Krista M. Sumby, Paul R. Grbin, Vladimir Jirane