A lipoxygenase with dual positional specificity is expressed in olives (Olea europaea L.) during ripening.

International audiencePlant lipoxygenases (LOXs) are a class of widespread dioxygenases catalysing the hydroperoxidation of polyunsaturated fatty acids. Although multiple isoforms of LOX have been detected in a wide range of plants, their physiological roles remain to be clarified. With the aim to clarify the occurrence of LOXs in olives and their contribution to the elaboration of the olive oil aroma, we cloned and characterized the first cDNA of the LOX isoform which is expressed during olive development. The open reading frame encodes a polypeptide of 864 amino acids. This olive LOX is a type-1 LOX which shows a high degree of identity at the peptide level towards hazelnut (77.3%), tobacco (76.3%) and almond (75.5%) LOXs. The recombinant enzyme shows a dual positional specificity, as it forms both 9- and 13-hydroperoxide of linoleic acid in a 2:1 ratio, and would be defined as 9/13-LOX. Although a LOX activity was detected throughout the olive development, the 9/13-LOX is mainly expressed at late developmental stages. Our data suggest that there are at least two Lox genes expressed in black olives, and that the 9/13-LOX is associated with the ripening and senescence processes. However, due to its dual positional specificity and its expression pattern, its contribution to the elaboration of the olive oil aroma might be considered

Systematic Gene Overexpression in Candida albicans identifies a Regulator of Early Adaptation to the Mammalian Gut

We are grateful to members of the genomics core facility (PF2, Génopole) for the availability of the microarray scanner and the Alain Jacquier’s lab for making the GenePix software available. We are grateful to Drs. Suzanne Noble and Aaron Mitchell for providing C. albicans mutant collections. We thank all members of the Fungal Biology & Pathogenicity Unit, particularly Drs. Anne Neville and Adeline Feri for their numerous insights during the course of this project. This work has been supported by grants from the Agence Nationale de la Recherche (KANJI, ANR-08-MIE-033-01 to C.d’E. and F.D.; ERA-Net Infect-ERA, FUNCOMPATH, ANR-14-IFEC-0004; and CANDIHUB, ANR-14-CE-0018 to C.d’E.), the French Government’s Investissement d’Avenir program (Laboratoire d’Excellence Integrative Biology of Emerging Infectious Diseases, ANR-10-LABX-62-IBEID to C.d’E.; Institut de Recherche Technologique BIOASTER, ANR-10-AIRT-03 to C.d’E., F.D. and T.J.), the European Commission (FinSysB PITN-GA-2008-214004 to C.d’E.) and the Wellcome Trust (The Candida albicans ORFeome project, WT088858MA to C.d’E. and C.M.). C.M. acknowledges support from the Medical Research Council, UK (New Investigator Award, G0400284), the MRC Centre for Medical Mycology (MR/N006364/1) and the University of Aberdeen. S.Z. is an Institut Pasteur International Network Affiliate Program Fellow. S.Z., L.v.W. and A.H.C. were the recipients of post-doctoral fellowships from the European Commission (FINSysB, PITN-GA-2008-214004 to S.Z.), the Agence Nationale de la Recherche (KANJI, ANR-08-MIE-033-01 to S.Z.; ERA-Net Infect-ERA, FUNCOMPATH, ANR-14-IFEC-0004 to A.H.C.; CANDIHUB, ANR-14-CE-0018 to L.v.W) and the French Government’s Investissement d’Avenir program (Institut de Recherche Technologique BIOASTER, ANR-10-AIRT-03 to S.Z. and A.H.C.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The Effect of Doxycycline on PMA-Induced MUC5B Expression via MMP-9 and p38 in NCI-H292 Cells

ObjectivesDoxycycline is commonly used in medicine for its bacteriostatic antimicrobial properties. Recent studies have reported that doxycycline also has anti-inflammatory effects. Matrix metalloproteinase (MMP)-9 has been found to be involved in the physiological and pathological process of inflammatory airway disease. Phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, is known to stimulate the expression of MMP and mucin genes in the airway and intestinal epithelial cells. Therefore, the effects and signal pathways of doxycycline on PMA-induced MUC5B expression dependent MMP-9 in human airway epithelial cells were investigated.MethodsIn human NCI-H292 airway epithelial cells, MUC5B and MMP-9 mRNA expression, MUC5B protein expression, and MMP-9 protein activity after the treatment with PMA, MMP-9 or doxycycline were determined by reverse transcriptase-polymerase chain reaction, enzyme immunoassay, gelatin zymography, and Western blot analysis.ResultsPMA increased MMP-9 and MUC5B expression. MMP-9 increased MUC5B expression. Doxycycline inhibited PMA-induced MUC5B expression, and PMA-induced MMP-9 mRNA expression and protein activity. Doxycycline inhibited phosphorylation of p38 induced by PMA and MMP-9.ConclusionThe results of this study suggest that doxycycline inhibited PMA-induced MUC5B mRNA expression and protein production through the MMP-9 and p38 pathways in human NCI-H292 airway epithelial cells

Dietary n-3 fatty acids have suppressive effects on mucin upregulation in mice infected with Pseudomonas aeruginosa

International audienceMucin hypersecretion and mucus plugging in the airways are characteristic features of chronic respiratory diseases like cystic fibrosis (CF) and contribute to morbidity and mortality. In CF, Pseudomonas aeruginosa superinfections in the lung exacerbate inflammation and alter mucus properties. There is increasing evidence that n-3 polyunsaturated fatty acids (PUFAs) exhibit anti-inflammatory properties in many inflammatory diseases while n-6 PUFA arachidonic acid (AA) favors inflammatory mediators such as eicosanoids prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) that may enhance inflammatory reactions. This suggests that n-3 PUFAs may have a protective effect against mucus over-production in airway diseases. Therefore, we hypothesized that n-3 PUFAs may downregulate mucins expression. We designed an absolute real-time PCR assay to assess the effect of a 5-week diet enriched either with n-3 or n-6 PUFAs on the expression of large mucins in the lungs of mice infected by P. aeruginosa. Dietary fatty acids did not influence mucin gene expression in healthy mice. Lung infection induced an increase of the secreted gel-forming mucin Muc5b and a decrease of the membrane bound mucin Muc4. These deregulations are modulated by dietary fatty acids with a suppressive effect of n-3 PUFAs on mucin (increase of Muc5b from 19-fold up to 3.6 x 10(5)-fold for the n-3 PUFAs treated group and the control groups, respectively, 4 days post-infection and decrease of Muc4 from 15-fold up to 3.2 x 10(4)-fold for the control and the n-3 PUFAs treated groups, respectively, 4 days post-infection). Our data suggest that n-3 PUFAs enriched diet represents an inexpensive strategy to prevent or treat mucin overproduction in pulmonary bacterial colonization

Reproducibility of Heart Rate Variability Indices in Children with Cystic Fibrosis

Fundamental to the potential utilisation of heart rate variability (HRV) indices as a prognostic tool is the reproducibility of these measures. The purpose of the present study was therefore to investigate the reproducibility of 24-hour derived HRV indices in a clinical paediatric population. Eighteen children (10 boys; 12.4 ± 2.8 years) with mild to moderate Cystic Fibrosis (CF; FVC: 83 ± 12% predicted; FEV1: 80 ± 9% predicted) and eighteen age- and sex-matched controls (10 boys; 12.5 ± 2.7 years) wore a combined ECG and accelerometer for two consecutive days. Standard time and frequency domain indices of HRV were subsequently derived. Reproducibility was assessed by Bland-Altman plots, 95% limits of agreement and intra-class correlation coefficients (ICC). In both groups, there was no systematic difference between days, with the variables demonstrating a symmetrical, homoscedastic distribution around the zero line. The time domain parameters demonstrated a good to excellent reproducibility irrespective of the population considered (ICC: 0.56 to 0.86). In contrast, whilst the frequency domain parameters similarly showed excellent reproducibility in the healthy children (ICC: 0.70 to 0.96), the majority of the frequency domain parameters illustrated a poor to moderate reproducibility in those with CF (ICC: 0.22 to 0.43). The exceptions to this trend were the normalised LF and HF components which were associated with a good to excellent reproducibility. These findings thereby support the utilisation of time and relative frequency domain HRV indices as a prognostic tool in children with CF. Furthermore, the present results highlight the excellent reproducibility of HRV in healthy children, indicating that this may be a useful tool to assess intervention effectiveness in this population