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L Cuzin,
S Trabelsi, P Delobel,
C Barbuat,
J Reynes,
C Allavena,
G Peytavin,
J Ghosn,
C Lascoux-Combe,
C Psomas,
P Corbeau,
P Flandre
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ABSTRACT: OBJECTIVE:: To address the ability of a 24-week MVC intensification of a stable anti-retroviral therapy (cART) to significantly increase the CD4 cell count slope. PATIENTS AND METHODS:: Patients were eligible if they had CD4<350cells/mm, a CD4 slope <50 cells/mm/year, and sustained plasma HIV-RNA <50copies/ml over the last two years, while receiving a stable cART. Patients harboring pure X4-using viruses by a phenotypic tropism assay were excluded. MVC was added to cART for 24 weeks, at the recommended dosage per drug-drug interactions. The primary endpoint was a significant positive difference in CD4 slopes (with MVC - pre MVC, paired t test). RESULTS:: Sixty patients (55 men), with median age 51y, baseline CD4 238cells/mm, and slope prior to intensification +14.1cells/mm/y were included. CD4 nadir was <50/mm in 47% of the population. The full set (FS) of patients (N=57) completed W24, and the on-treatment (OT) patients (N=48) did not discontinue MVC. The median CD4 slope difference from baseline was +22.6 cells/mm/y (p=0.08) in FS and +22.6 cells/mm/y (p=0.04) in OT. Slope evolution was not different according to baseline tropism, CD4 nadir, or ongoing cART regimen. No drug-related severe adverse events were recorded during intensification. MVC plasma concentrations were significantly different depending on drug-drug interaction with ongoing cART regimen and tended to be correlated with CD4 cells increase. CONCLUSION:: In this study, MVC intensification of stable cART over 24 weeks was able to enhance CD4 cells slopes in patients with prior insufficient immune restoration despite long term virological control.
JAIDS Journal of Acquired Immune Deficiency Syndromes 09/2012; · 4.43 Impact Factor
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ABSTRACT: Aims: To show that in anaerobic fermentation with limiting lipid nutrients, cell preparation impacts the viability assessment of yeast cells, and to identify the factors involved. Methods and Results: Saccharomyces cerevisiae viability was determined using propidium iodide staining and the flow cytometry. Analyses identified intact cells, dead cells and, under certain conditions, the presence of a third subpopulation of apparently damaged cells. This intermediate population could account for up to 40% of the entire cell population. We describe, analyse and discuss the effects of different solutions for cell resuspension on the respective proportion of these three populations, in particular that of the intermediate population. We show that this intermediate cell population forms in the absence of Ca(2+) /Mg(2+) . Conclusions: Cell preparation significantly impacts population viability assessment by FCM. The intermediate population, revealed under certain conditions, could be renamed as 'fragile cells'. For these cells, Ca(2+) and Mg(2+) reduce cell membrane permeability to PI. Significance and Impact of the Study: This is the first study that analyses and discusses the factors influencing the formation of an intermediate population when studying viability in yeast alcoholic fermentation. With a wider application in biological research, this study provides important support to the relatively new questioning of propidium iodide staining as a universal cell death indicator.
Letters in Applied Microbiology 08/2012; · 1.62 Impact Factor
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ABSTRACT: The hybrid nature of lager-brewing yeast strains has been known for 25 years; however, yeast hybrids have only recently been described in cider and wine fermentations. In this study, we characterized the hybrid genomes and the relatedness of the Eg8 industrial yeast strain and of 24 Saccharomyces cerevisiae/Saccharomyces kudriavzevii hybrid yeast strains used for wine making in France (Alsace), Germany, Hungary, and the United States. An array-based comparative genome hybridization (aCGH) profile of the Eg8 genome revealed a typical chimeric profile. Measurement of hybrids DNA content per cell by flow cytometry revealed multiple ploidy levels (2n, 3n, or 4n), and restriction fragment length polymorphism analysis of 22 genes indicated variable amounts of S. kudriavzevii genetic content in three representative strains. We developed microsatellite markers for S. kudriavzevii and used them to analyze the diversity of a population isolated from oaks in Ardèche (France). This analysis revealed new insights into the diversity of this species. We then analyzed the diversity of the wine hybrids for 12 S. cerevisiae and 7 S. kudriavzevii microsatellite loci and found that these strains are the products of multiple hybridization events between several S. cerevisiae wine yeast isolates and various S. kudriavzevii strains. The Eg8 lineage appeared remarkable, since it harbors strains found over a wide geographic area, and the interstrain divergence measured with a (δμ)(2) genetic distance indicates an ancient origin. These findings reflect the specific adaptations made by S. cerevisiae/S. kudriavzevii cryophilic hybrids to winery environments in cool climates.
Applied and environmental microbiology 02/2012; 78(9):3256-65. · 3.69 Impact Factor
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ABSTRACT: Medium-chain fatty acids (octanoic and decanoic acids) are well known as fermentation inhibitors. During must fermentation, the toxicity of these fatty acids is enhanced by ethanol and low pH, which favors their entrance in the cell, resulting in a decrease of internal pH. We present here the characterization of the mechanisms involved in the establishment of the resistance to these fatty acids. The analysis of the transcriptome response to the exposure to octanoic and decanoic acids revealed that two partially overlapping mechanisms are activated; both responses share many genes with an oxidative stress response, but some key genes were activated differentially. The transcriptome response to octanoic acid stress can be described mainly as a weak acid response, and it involves Pdr12p as the main transporter. The phenotypic analysis of knocked-out strains confirmed the role of the Pdr12p transporter under the control of WAR1 but also revealed the involvement of the Tpo1p major facilitator superfamily proteins (MFS) transporter in octanoic acid expulsion. In contrast, the resistance to decanoic acid is composite. It also involves the transporter Tpo1p and includes the activation of several genes of the beta-oxidation pathway and ethyl ester synthesis. Indeed, the induction of FAA1 and EEB1, coding for a long-chain fatty acyl coenzyme A synthetase and an alcohol acyltransferase, respectively, suggests a detoxification pathway through the production of decanoate ethyl ester. These results are confirmed by the sensitivity of strains bearing deletions for the transcription factors encoded by PDR1, STB5, OAF1, and PIP2 genes.
Applied and environmental microbiology 11/2010; 76(22):7526-35. · 3.69 Impact Factor
