Quantifying the combined effects of the heating time, the temperature and the recovery medium pH on the regrowth lag time of Bacillus cereus spores after a heat treatment

International audienceThe purpose of this study was to quantify the lag time of re-growth of heated spores of Bacillus cereus as a function of the conditions of the heat treatment: temperature, duration and pH of the recovery medium. For a given heating temperature, curves plotting lag times versus time of heating show more or less complex patterns. However, under a heating time corresponding to a decrease of 2 decimal logarithms of the surviving populations of spores, a linear relationship between the lag time of growth and the time of the previous heat treatment can be observed. The slope of this linear relationship followed itself a Bigelow type linear relationship, the slope of which yielded a - value very close to the observed conventional z-value. It was then concluded that the slope of the regrowth lag time versus the heating time followed a linear relationship with the sterilisation value reached in the course of the previous heat treatment. A sharp effect of the pH of the medium which could be described by a simple "secondary" model was observed. As expected, the observed intercept of the linear relationship between lag time and heating time (lag without previous heating) was dependent on only the pH of the medium and not on the heating temperature

Survival curves of heated bacterial spores: effect of environmental factors on Weibull parameters

International audienceThe classical D-value of first order inactivation kinetic is not suitable for quantifying bacterial heat resistance for non-log linear survival curves. One simple model derived from the Weibull cumulative function describes non-log linear kinetics of micro-organisms. The influences of environmental factors on Weibull model parameters, shape parameter "p" and scale parameter "delta", were studied. This paper points out structural correlation between these two parameters. The environmental heating and recovery conditions do not present clear and regular influence on the shape the parameter "p" and could not be described by any model tried. Conversely, the scale parameter "delta" depends on heating temperature and heating and recovery medium pH. The models established to quantify these influences on the classical "D" values could be applied to this parameter "delta". The slight influence of the shape parameter p variation on the goodness of fit of these models can be neglected and the simplified Weibull model with a constant p-value for given microbial population can be applied for canning process calculations

Validation of the French Version of the Yale Food Addiction Scale: An Examination of Its Factor Structure, Reliability and Construct Validity in a Nonclinical Sample

International audienceObjective: Food addiction is a concept that has recently been proposed by applying the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, criteria for substance dependence to eating behaviour. Food addiction has received increased attention given that it may play a role in binge eating, eating disorders, and the recent increase in obesity prevalence. Currently, there is no psychometrically sound tool for assessing food addiction in French. Our study aimed to test the psychometric properties of a French version of the Yale Food Addiction Scale (YFAS) by establishing its factor structure, internal consistency, and construct validity in a nonclinical population.Method: A total of 553 participants were assessed for food addiction (French version of the YFAS) and binge eating behaviour (Bulimic Investigatory Test, Edinburgh and Binge Eating Scale). We tested the scale’s factor structure (factor analysis for dichotomous data based on tetrachoric correlation coefficients), internal consistency, and construct validity with measures of binge eating.Results: Our results supported a 1-factor structure, which accounted for 54.1% of the variance. We demonstrated that this tool had adequate reliability and highly construct validity with measures of binge eating in this population, both in its diagnosis and symptom count version. A 2-factor structure explained an additional 9.1% of the variance, and could help to differentiate between patients with high, compared with low, levels of insight regarding addiction symptoms.Conclusions: In our study, we validated a psychometrically sound French version of the YFAS, both in its symptom count and diagnosis version. Future studies should validate this tool in clinical samples

High preoperative depression, phobic anxiety, and binge eating scores and low medium-term weight loss in sleeve gastrectomy obese patients: a preliminary cohort study.: Psychiatric factors and weight loss in obesity surgery

International audienceOBJECTIVE: Although depression, anxiety, and binge eating are prevalent in candidates for bariatric surgery, their impact on weight loss is unknown following sleeve gastrectomy. This study assesses the associations between weight loss and preoperative depression, anxiety, and binge eating scores in patients undergoing sleeve gastrectomy for morbid obesity. METHOD: This cohort study included 34 patients who underwent sleeve gastrectomy for morbid obesity between May 2006 and February 2010 in a French tertiary referral center. We assessed preoperative depression (using the Beck depression inventory and the SCL-90-R depression subscale), anxiety (using the Hamilton anxiety rating scale and the SCL-90-R anxiety subscales), and binge eating (using the bulimic investigatory test, Edinburgh). The primary outcome was the percentage of excess weight loss at 12 months (PEWL). RESULTS: The preoperative mean body mass index (BMI) was 55.3 kg/m2 ± 10.2 kg/m2 and 41.7 kg/m2 ± 8.7 kg/m2 at the 12-month follow-up visit. The mean PEWL was 46.8% ± 15.8%. After adjusting for the preoperative BMI, the PEWL was negatively associated with preoperative scores for depression (β= -0.357; P < 0.05), phobic anxiety (β = -0.340; P < 0.05), interpersonal sensitivity (β = -0.328; P < 0.05), and binge eating (β = -0.315; P = 0.05). Other forms of anxiety were not correlated with the PEWL. CONCLUSIONS: Higher preoperative depression, phobic anxiety, interpersonal sensitivity, and binge eating scores are associated with low postoperative weight loss in patients undergoing sleeve gastrectomy. Future studies should assess the preoperative prevalence of syndromal or subsyndromal atypical depression and its relationship to postoperative weight loss in bariatric surgery candidates

The molecular structure of melts along the carbonatite–kimberlite–basalt compositional joint: CO2and polymerisation

International audienceTransitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remained largely unstudied. Their molecular structure has remained elusive in part because these melts are difficult to quench to glass. Here we use FTIR, Raman, 13C and 29Si NMR spectroscopy together with First Principle Molecular Dynamic (FPMD) simulations to investigate the molecular structure of transitional melts and in particular to assess the effect of CO2on their structure. We found that carbon in these glasses forms free ionic carbonate groups attracting cations away from their usual ‘depolymerising’ role in breaking up the covalent silicate network. Solution of CO2in these melts strongly modifies their structure resulting in a significant polymerisation of the aluminosilicate network with a decrease in NBO/Si of about 0.2 for every 5 mol% CO2dissolved.This polymerisation effect is expected to influence the physical and transport properties of transitional melts. An increase in viscosity is expected with increasing CO2content, potentially leading to melt ponding at certain levels in the mantle such as at the lithosphere–asthenosphere boundary. Conversely an ascending and degassing transitional melt such as a kimberlite would become increasingly fluid during ascent hence potentially accelerate. Carbon-rich transitional melts are effectively composed of two sub-networks:a carbonate and a silicate one leading to peculiar physical and transport properties

Segregation between SMCHD1 mutation, D4Z4 hypomethylation and Facio-Scapulo-Humeral Dystrophy: a case report

International audienceBackground: The main form of Facio-Scapulo-Humeral muscular Dystrophy is linked to copy number reduction of the 4q D4Z4 macrosatellite (FSHD1). In 5 % of cases, FSHD phenotype appears in the absence of D4Z4 reduction (FSHD2). In 70-80 % of these patients, variants of the SMCHD1 gene segregate with 4qA haplotypes and D4Z4 hypomethylation.Case presentation: We report a family presenting with neuromuscular symptoms reminiscent of FSHD but without D4Z4 copy reduction. We characterized the 4q35 region using molecular combing, searched for mutation in the SMCHD1 gene and determined D4Z4 methylation level by sodium bisulfite sequencing. We further investigated the impact of the SMCHD1 mutation at the protein level and on the NMD-dependent degradation of transcript. In muscle, we observe moderate but significant reduction in D4Z4 methylation, not correlated with DUX4-fl expression. Exome sequencing revealed a heterozygous insertion of 7 bp in exon 37 of the SMCHD1 gene producing a loss of frame with premature stop codon 4 amino acids after the insertion (c.4614-4615insTATAATA). Both wild-type and mutated transcripts are detected.Conclusion: The truncated protein is absent and the full-length protein level is similar in patients and controls indicating that in this family, FSHD is not associated with SMCHD1 haploinsufficiency

De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development

Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD