Diversity of lactic acid bacteria isolated from AOC Salers cheese

The objective of this work was to describe the diversity of lactic acid bacteria in traditional raw milk Salers cheeses at the species and strain levels. The characterization of 381 strains isolated during ripening and various strain collections was investigated using physiological analysis and molecular techniques: Rep-PCR, species and genus specific amplifications and the sequence analysis of 16S rDNA for strain typing and taxonomic identification. The strains belonged to Lactobacillus plantarum, Lactobacillus paracasei, Lactococcus lactis, Lactococcus garviae, Enterococcus faecalis, Enterococcus faecium, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Streptococcus salivarius, Streptococcus millieri, Streptococcus macedonicus and Pediococcus pentosaceus. A wide phenotypic and genomic heterogeneity was observed within the different species (Lactobacillus plantarum, Lactobacillus paracasei and Leuconostoc mesenteroides) according to the origin and the time of ripening. The natural microflora was different from strain collection and each method must be combined to identify and characterize natural microflora. This study revealed the low selectivity of selective media used for the isolation of different groups of lactic acid bacteria except the Facultatively Heterofermentative lactobacilli medium selecting mesophile lactobacilli and SB medium selective for Enterococcus. The study reveals, for the first time, the microbial lactic acid bacteria community of Salers cheese and its diversity. A better knowledge of microbial flora will be useful to improve understanding of sensory quality of cheeses.     

Solvent Extraction Investigations on Pu(IV) and Th(IV) Complexes with Hydrophilic SO3-Ph-BTP and SO3-Ph-BTBP Ligands

ABSTRACT

Complexation of Pu(IV) and Th(IV) cations by the title ligands – hydrophilic sulfophenyl triazinyl derivatives of bis-triazinyl-pyridine and -bipyridine – was studied in solvent extraction systems containing a TODGA extractant and one of these hydrophilic ligands. Stoichiometries and stability constants of the complexes formed in an acidic (HNO₃) aqueous phase have been determined. The Pu(IV) complexes are significantly stronger than their Th(IV) analogues. Only two complexes of each metal with SO₃-Ph-BTP (1:1 and 1:2) have been detected, and only one (1:1) with SO₃-Ph-BTBP; both numbers being less than expected based on the coordination numbers of the metal ions and on the denticities of the ligands. Possible reasons of this discrepancy are discussed.     

Nanoparticle-templated assembly of viral protein cages

Self-assembly of regular protein surfaces around nanoparticle templates provides a new class of hybrid biomaterials with potential applications in medical imaging and in bioanalytical sensing. We report here the first example of efficiently self-assembled virus-like particles (VLPs) having a brome mosaic virus protein coat and a functionalized gold core. The present study indicates that functionalized gold particles can initiate VLP assembly by mimicking the electrostatic behavior of the nucleic acid component of the native virus. These VLP constructs are symmetric, with the protein stoichiometry and packaging properties indicating similarity to the icosahedral packing of the capsid. Moreover, a pH-induced swelling transition of the VLPs is observed, in direct analogy to the native virus.     

Zinc bioavailability in wheat grain in relation to phosphorus fertiliser,crop sequence and mycorrhizal fungi

BACKGROUND: While human diets are often deficient in zinc (Zn), the impacts of crop management on Zn in cereal grains are rarely examined. In this study the effect of phosphorus (P) fertiliser and crop sequence (wheat following canola, linola, fallow or pasture) on wheat grain Zn concentration and bioavailability for humans was investigated. RESULTS: The Zn concentration of wheat grain decreased by 33–39% in response to P fertiliser. It was also 30–40% lower for crops following canola and fallow than for those following linola and pasture. P fertiliser decreased the colonisation of arbuscular mycorrhizal fungi (AMF) in wheat roots, and canola and fallow led to lower colonisation than linola and pasture. Since AMF are known to assist in soil uptake of immobile nutrients such as Zn, it is hypothesised that P fertiliser and crop sequence affected grain Zn concentration through AMF. P fertiliser also increased the concentrations of grain P by 17% and grain phytic acid (PA) by 19%, but had little effect on the concentrations of calcium (Ca), iron (Fe) and polyphenols. Other impacts of crop sequence were slightly higher concentrations in grain of P after pasture and Fe after canola. The bioavailability of grain Zn, as shown by the PA:Zn and Ca × PA:Zn molar ratios, mostly reflected Zn concentration and was low in all treatments. After milling, the PA:Zn molar ratio suggested low Zn bioavailability for flour from wheat grown with P fertiliser after canola or fallow. CONCLUSION: Crop management can affect the bioavailability of Zn in wheat grain, with practices leading to high yields potentially leading to low Zn bioavailability. Copyright © 2008 Society of Chemical Industry     

Predicting fatigue transverse crack growth in cross-ply carbon–epoxy laminates from quasi static strength tests by using iso-damage curves

Cross-ply laminates made of carbon/epoxy IM7/977-2 system are investigated. The fatigue study is confined to ambient temperature conditions and zero loading ratio. Damage is characterized by the transverse crack density ρ in the central 90°-layer. The family of experimental fatigue cracking curves (ρ versus N, where N is the number of cycles, for each tensile test maximum stress amplitude) can be replaced with a set of “iso-damage curves”, i.e. contour curves of constant ρ in the σ–log (N) plane. The iso-damage curves approximately constitute a fan of straight lines that intersect at a common point (σ_e, log (N_s)), where N_s is a very large number of cycles beyond which no more crack appears, and σ_e is some fatigue limit.Our aim is to propose a simple method to predict fatigue cracking at an arbitrary maximum stress level loading by using data stemming from a constant strain rate test. This method essentially rests upon the construction of the above “iso-damage” curves, using very simple assumptions.     

Effect of Carnobacterium piscicola on aroma formation in sausage mince

The metabolites from leucine degradation play a key role in sausage aroma. Leucine catabolism is particularly important in Carnobacterium piscicola. The purpose of the study was to determine the effect of C. piscicola inoculation on the aroma of a sausage model and on leucine catabolism. Sensory analysis and implantation of Carnobacterium were performed. Aromatic compound production from (3)H leucine added to the sausage model was measured by high-performance liquid chromatography. After 18 days of ripening, the level of Carnobacterium species was 10-fold higher in sausages inoculated with C.?piscicola than in the control sausages. Addition of C.?piscicola enhanced the development of sausage aroma. The leucine was 10% more degraded in the models inoculated with C. piscicola. 3-Methyl butanoic acid was the main metabolite detected and the highest production of α-ketoisocaproic acid and hydroxy α-ketoisocaproic acid were detected in the sausage model inoculated with C. piscicola.     

Les variables cognitives impliquées dans l'inquiétude face à la maladie.

The essential feature of Hypochondriasis is preoccupation with fear of having a serious disease based on a misinterpretation of bodily symptoms. While it is classified as a somatoform disorder, it presents many similarities with anxiety disorders, particularly Generalized Anxiety Disorder (GAD) which is core feature is excessive worry. Since these disorders present similar symptoms, it is also possible that similar cognitive mechanisms may be involved in their development and maintenance. The goal of the present study was to verify the relationship between illness worry and cognitive mechanisms related to GAD: Intolerance of uncertainty, faulty believes about the usefulness of worry, negative problem orientation, and cognitive avoidance. Three hundred and forty six adults (N=346) participated in this correlational study by completing relevant questionnaires. Results demonstrated that most GAD mechanisms were significant predictors of illness worry. Cognitive avoidance and negative problem orientation, entered first in the model, were the strongest predictors of the variance in illness worry scores. Faulty beliefs about worry explained only a marginal part of that variance once the first two predictors have been entered. Results also suggested that cognitive avoidance was a better predictor of illness worry compared to somatosensory-amplification, a cognitive mechanism considered as central in understanding Hypochondriasis (see Barsky & Wyshak, 1990). Clinical implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diagnosis Support System based on clinical guidelines: comparison between Case-Based Fuzzy Cognitive Maps and Bayesian Networks

Several studies have described the prevalence and severity of diagnostic errors. Diagnostic errors can arise from cognitive, training, educational and other issues. Examples of cognitive issues include flawed reasoning, incomplete knowledge, faulty information gathering or interpretation, and inappropriate use of decision-making heuristics. We describe a new approach, case-based fuzzy cognitive maps, for medical diagnosis and evaluate it by comparison with Bayesian belief networks. We created a semantic web framework that supports the two reasoning methods. We used database of 174 anonymous patients from several European hospitals: 80 of the patients were female and 94 male with an average age 45 ± 16 (average ± stdev). Thirty of the 80 female patients were pregnant. For each patient, signs/symptoms/observables/age/sex were taken into account by the system. We used a statistical approach to compare the two methods.     

Stability Investigation of Se- and Te-Substituted Tetrahedrite

Density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) calculations have been performed to investigate the influence of Se and Te substitutions on the stability of tetrahedrite. The formation energies, the Laplacian of the electron density, the total and local volume changes and the site charge changes have been determined. The DFT results show that the single-atom substitution is the most preferred, and that selenium is preferred for sulphur replacement, whereas antimony can be equally replaced by selenium and tellurium. However, as selenium substitutes for either sulphur or antimony, QTAIM calculations evidenced large structural and chemical changes in the structures. Additional experimental results, in agreement with QTAIM results, allow us to conclude that the investigation of alloy stability cannot be limited to DFT calculations of formation energies and total volume changes. QTAIM appears to be a valuable complementary method for obtaining information on phase stability.