These four compounds can therefore be considered as potential markers of differentiation between a fresh product and one that has been frozen.

The initiation of starch granule formation is still poorly understood. However, the soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthesize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast two-hybrid screen allowed the identification of several putative SS4 interacting partners. We identified the product of At4g32190 locus as a chloroplast-targeted PROTEIN INVOLVED IN STARCH INITIATION (named PII1). Arabidopsis mutants devoid of PII1 display an alteration of the starch initiation process and accumulate, on average, one starch granule per plastid instead of the five to seven granules found in plastids of wild-type plants. These granules are larger than in wild-type, and they remain flat and lenticular. pii1 mutants display wild-type growth rates and accumulate standard starch amounts. Moreover, starch characteristics, such as amylopectin chain length distribution, remain unchanged. Our results reveal the involvement of PII1 in the starch priming process in Arabidopsis leaves through interaction with SS4.

SPME/GC/MS combined with a statistical multivariate approach may be a useful method to identify volatile compounds and characterise fish freshness during storage.

Bacterial species from the Bacillus genus, including Bacillus cereus and Bacillus anthracis, synthesize secondary cell wall polymers (SCWP) covalently associated to the peptidoglycan through a phospho-diester linkage. Although such components were observed in a wide panel of B. cereus and B. anthracis strains, the effect of culture conditions or of bacterial growth state on their synthesis has never been addressed. Herein we show that B. cereus ATCC 14579 can synthesize not only one, as previously reported, but two structurally unrelated secondary cell wall polymers (SCWP) polysaccharides. The first of these SCWP, 34)[GlcNAc(␤1-3)]GlcNAc(␤1-6)[Glc(␤1-3)][ManNAc(␣1-4)]GalNAc(␣1-4)ManNAc(␤13, although presenting an original sequence, fits to the already described the canonical sequence motif of SCWP. In contrast, the second polysaccharide was made up by a totally original sequence, 36)-Gal(␣1-2)(2-R-hydroxyglutar-5-ylamido)Fuc2NAc4N(␣1-6)GlcNAc(␤13, which no equivalent has ever been identified in the Bacillus genus. In addition, we established that the syntheses of these two polysaccharides were differently regulated. The first one is constantly expressed at the surface of the bacteria, whereas the expression of the second is tightly regulated by culture conditions and growth states, planktonic, or biofilm.The cell wall surrounding cytoplasmic membrane is of prime importance in bacteria survival and adaptation to their environment. In Gram-positive bacteria, the cell wall includes a thick multilayer peptidoglycan to which most often are associated other cell-surface structures called secondary cell wall polymers (SCWPs) 4 (1). These secondary cell wall polymers include lipoteichoic acids anchored in the outer leaflet of plasmic membrane as well as teichoic acids, teichuronic acids, or neutral polysaccharides (SCWP polysaccharides), which are covalently bound, through a phosphodiester link, to the N-acetyl muramic acid moieties of the peptidoglycan. SCWPs are essential in Bacillus subtilis and were shown to be involved in the bacterial virulence in Staphylococcus aureus (2). In addition, SCWPs bind SLH (S-layer homology) domains containing proteins, thus anchoring them non-covalently to the cell wall (3). These proteins are involved in various functions, including peptidoglycan maturation (4, 5), binding to host tissues (6), or protein degradation (7). Teichoic acids and the secondary cell wall polysaccharide were also reported to be involved in biofilm formation (8 -10).Biofilms are multicellular structures attached to a solid or a liquid surface and embedded in a self-produced matrix. This matrix is made of polymers, mostly polysaccharides, DNA, and/or proteins, provides cohesion to the bacterial community (11-13), and acts as a shield, protecting bacteria within the biofilm. Biofilms are, therefore, persistent structures, resisting desiccation, cleaning procedures, and antimicrobial substances (14), which makes them a challenge in human health and industrial processes. Several species from the Bacillus genus, in...

This study was designed to establish the presence and function of the mucous layer surrounding spores of Bacillus subtilis. First, an external layer of variable thickness and regularity was often observed on B. subtilis spores. Further analyses were performed on B. subtilis 98/7 spores surrounded by a thick layer. The mechanical removal of the layer did not affect their resistance to heat or their ability to germinate but rendered the spore less hydrophilic, more adherent to stainless steel, and more resistant to cleaning. This layer was mainly composed of 6-deoxyhexoses, ie rhamnose, 3-O-methyl-rhamnose and quinovose, but also of glucosamine and muramic lactam, known also to be a part of the bacterial peptidoglycan. The specific hydrolysis of the peptidoglycan using lysozyme altered the structure of the required mucous layer and affected the physico-chemical properties of the spores. Such an outermost mucous layer has also been seen on spores of B. licheniformis and B. clausii isolated from food environments.

Producers of processed anchovies have developed hazard analysis and critical control points (HACCP) to guarantee the quality of their products. Nonetheless there is a lack of objective data to determine products' shelf life. The quality of a product is usually established on the basis of its safety and organoleptic properties. These parameters were assessed by monitoring the profiles of volatile compounds and quantitating six biogenic amines in samples of two types of processed anchovies during their shelf life. With regard to biogenic amines, quantities were below the regulatory limits throughout shelf life, except when a temperature abuse was applied for marinated samples. Moreover, this work highlights an optimum volatile profile at 5 and 6 months of storage for salted and marinated anchovies, respectively. This is the result of a higher content of six aldehyde and nine ketone compounds, mainly from lipid oxidation.

Lactose was fermented but not assimilated by the strain Bifidobacterium bifidum DSM 20082. The sugar uptake was measured with lactose 14C. Km and V(max) values were respectively 2.6 mM and 12.11 nmol/min/mg of cell protein. The lactose transport system and the beta-D-galactosidase were stimulated when the cells were grown with lactose, but isopropyl-beta-D-thiogalactopyranoside had no effect. Lactose uptake was inhibited by compounds which interfered with proton and metal ionophore. Na+, Li+, or K+ did not affect incorporation of lactose. Furthermore, the lactose uptake decreased when an inhibitor of ATP synthesis was used. From the results of this study, the stain contained an active lactose transport system, probably a proton symport as described for Escherichia coli but with a different regulation system.

The diagnosis of systemic Candida infections is a recognized challenge. We developed a mass spectrometry strategy to detect signals from Candida molecules in patients' sera. Pre-analytical procedures were designed to extract oligosaccharides from serum. A peak m/z of at 365 was specifically revealed in sera from patients with candidaemia with regard to healthy controls. This biomarker was identified as a disaccharide, its presence did not correlate with mannanaemia or glucanaemia. Mouse models of Candida albicans colonization and infection showed that the signal was specifically associated with tissue invasion, suggesting that clinical evaluation of its usefulness in discriminating colonized and infected patients would be worthwhile.