Impact of 20∶4n−6 supplementation on the fatty acid composition and hemocyte parameters of the pacific oyster crassostrea gigas

Arachidonic acid (20∶4n−6, ArA) and its eicosanoid metabolites have been demonstrated to be implicated in immune functions of vertebrates, fish, and insects. Thus, the aim of this study was to assess the impact of ArA supplementation on the FA composition and hemocyte parameters of oysters Crassostrea gigas. Oyster dietary conditioning consisted of direct addition of ArA solutions at a dose of 0, 0.25, or 0.41 μg ArA per mL of seawater into tanks in the presence or absence of T-Iso algae. Results showed significant incorporation of ArA into gill polar lipids when administered with algae (up to 19.7%) or without algae (up to 12.1%). ArA supplementation led to an increase in hemocyte numbers, phagocytosis, and production of reactive oxygen species by hemocytes from ArA-supplemented oysters. Moreover, the inhibitory effect of Vibrio aestuarianus extracellular products on the adhesive proprieties of hemocytes was lessened in oysters fed ArA-supplemented T-Iso. All changes in oyster hemocyte parameters reported in the present study suggest that ArA and/or eicosanoid metabolites affect oyster hemocyte functions.     

Impact of the guanidinium group on hybridization and cellular uptake of cationic oligonucleotides

The grafting of cationic groups to synthetic oligonucleotides (ONs) in order to reduce the charge repulsion between the negatively charged strands of a duplex or triplex, and consequently to increase a complex's stability, has been extensively studied. Guanidinium groups, which are highly basic and positively charged over a wide pH range, could be an efficient ON modification to enhance their affinity for nucleic acid targets and to improve cellular uptake. A straightforward post-synthesis method to convert amino functions attached to ONs (on sugar, nucleobase or backbone) into guanidinium tethers has been perfected. In comparison to amino groups, such cationic groups anchored to alpha-oligonucleotide phosphoramidate backbones play important roles in duplex stability, particularly with RNA targets. This high affinity could be explained by dual recognition resulting from Watson-Crick or Hoogsteen base pairing combined with cationic/anionic backbone recognition between strands involving H-bond formation and salt bridging. Molecular-dynamics simulations corroborate interactions between the cationic backbones of the alpha-ONs and the anionic backbones of the nucleic acid targets. Moreover, ONs with guanidinium modification increased cellular uptake relative to negatively charged ONs. The cellular localization of these new cationic phosphoramidate ONs is mainly cytoplasmic. The uptake of these ON analogues might occur through endocytosis.     

Reevaluation of the violacein biosynthetic pathway and its relationship to indolocarbazole biosynthesis

The biosynthetic pathways for violacein and for indolocarbazoles (rebeccamycin, staurosporine) include a decarboxylative fusion of two tryptophan units. However, in the case of violacein, one of the tryptophans experiences an unusual 1-->2 shift of the indole ring. The violacein biosynthetic gene cluster was previously reported to consist of four genes, vioABCD. Here we studied the violacein pathway through expression of vio genes in Escherichia coli and Streptomyces albus. A pair of genes (vioAB), responsible for the earliest steps in violacein biosynthesis, was functionally equivalent to the homologous pair in the indolocarbazole pathway (rebOD), directing the formation of chromopyrrolic acid. However, chromopyrrolic acid appeared to be a shunt product, not a violacein intermediate. In addition to vioABCD, a fifth gene (vioE) was essential for violacein biosynthesis, specifically for production of the characteristic 1-->2 shift of the indole ring. We also report new findings on the roles played by the VioC and VioD oxygenases, and on the origin of violacein derivatives of the chromoviridans type.     

Release and oxidation of cell-bound saxitoxins during chlorination of Anabaena circinalis cells

Surface water sources are increasingly subject to proliferation of toxic cyanobacteria. Direct chlorination of source water containing toxic cyanobacterial cells for different treatment purposes might cause cell damage and toxin release. There is limited information available on chlorination of saxitoxins (STXs: saxitoxin, C-toxins, and gonyautoxins) produced by Anabaena circinalis. This work: (1) investigated the impact of chlorination on cell lysis and toxin/odor compound release in natural waters; (2) assessed the rates of chlorination of total STXs, and (3) estimated apparent rate constants for STX oxidation in ultrapure and natural waters. With a chlorine exposure (CT) value of 7.0 mg x min/L all cells lost viability causing toxin release. Cell-membrane damage occurred faster than released STXs oxidation. All saxitoxin and more than 95% of other STX analogues were subsequently oxidized. Kinetic analysis of the oxidation of STX analogues revealed significant differences in the susceptibility to chlorine, saxitoxin being the easiest to oxidize. Also, concentrations of trihalomethanes, haloacetic acids, and N-nitrosodimethylamine as chlorination byproducts were respectively <50 μg/L and 11 ng/L even at the highest CT value (50.3 mg x min/L).     

Pyrene and phenanthrene sorption to model and natural geosorbents in single- and binary-solute systems

Sorption of pyrene and phenanthrene to model (illite and charcoal) and natural (Yangtze sediment) geosorbents were investigated by batch techniques using fluorescence spectroscopy. A higher adsorption of phenanthrene was observed with all sorbents, which is related to the better accessibility of smaller molecules to micropores in the molecular sieve sorbents. In addition, pyrene sorption in binary-solute systems with a constant initial concentration of phenanthrene (0.1 μmol L(-1) or 2 μmol L(-1)) was studied. A 0.1 μmol L(-1) concentration of phenanthrene causes no competitive effect on the pyrene sorption. A 2 μmol L(-1) concentration of phenanthrene significantly suppresses the sorption of pyrene, especially in the low concentration range; nonlinearity of the pyrene sorption isotherms thus decreases. The competitive effect of 2 μmol L(-1) phenanthrene on the pyrene sorption is overestimated by the ideal adsorbed solution theory (IAST) using the fitted single sorption results of both solutes. An adjustment of the IAST application by taking into account the molecular sieve effect is proposed, which notably improves the IAST prediction for the competitive effect.     

Consumer preferences for fresh tomato at the European scale: a common segmentation on taste and firmness

Although tomato flavor has not been a major goal for breeders, nowadays it becomes important as it is a subject of consumer complaint. A better knowledge of tomato consumer preferences, at the European level, should provide the basis for improvement of fruit quality and for market segmentation. In the framework of a large European project, 806 consumers from 3 countries, The Netherlands, France, and Italy, were presented with a set of 16 varieties representing the diversity of fresh tomato offer in order to evaluate their preferences. In parallel, sensory profiles were constructed by expert panels in each country. Preference maps were then constructed in each country revealing the structure of consumer preferences and allowing identification of the most important characteristics. Then a global analysis revealed that preferences were quite homogeneous across countries. This study identified the overall flavor and firmness as the most important traits for improving tomato fruit quality. It showed that consumer preferences from different European countries, with different cultures and food practices, are segmented following similar patterns when projected onto a common referential plan. Moreover, the results clearly showed that diversification of taste and texture is required to satisfy all consumers' expectations as some consumers preferred firm tomatoes, while others preferred melting ones and were more or less demanding in terms of sweetness and flavor intensity. Detailed comparisons also showed the importance of the fruit appearance in consumer preference.     

Osmosonication of blackberry juice: impact on selected pathogens, spoilage microorganisms, and main quality parameters

Osmosonication combines ultrasound with nonthermal concentration. It was applied on tropical highland blackberry (Rubus adenotrichus) juice over different periods of time to assess reductions in microorganism and the impact on main quality parameters. This juice had been inoculated with Salmonella spp., Shigella sp., a lactic acid bacterium, yeasts, and molds. It was then sonicated for 5.9 to 34.1 min at 20 kHz and 0.83 W/mL. Nonthermal concentration was simulated by mixing the juice with a concentrate to obtain 650 g TSS/kg. It was then stored at -18 °C for up to 82 h. The lactic acid bacterium, yeasts, and molds were reduced by 1.60 to as much as 5.01 log(10) CFU/mL, whereas, for pathogens, reductions were total ≥7.1 log(10) CFU/mL after 24 h of storage, even for juice not sonicated, because of low pH. Color, antioxidant capacity, anthocyanins, and ellagitannins did not change significantly during sonication treatment up to 32 min. However, an off-flavor was detected after 8 min of sonication. Nonetheless, osmosonication can be considered as an alternative to thermal processes for producing safe and high-quality concentrates. PRACTICAL APPLICATION: Osmosonication represents a potential processing alternative for producing safe and high-quality concentrated fruit juice without applying thermal treatments. Findings reported in this article can also be applied by industries when concentrating juices by classical means at relatively low temperature. It provides industries with a mathematical model specific for blackberry juice, from which different combinations of sonication time and storage time of concentrate can be chosen to achieve safety and quality goals.     

来吧!在柔软中战斗!

Les M已经为Pompidou-Metz中心的儿童工作坊设计出了一个柔软鲜艳的世界,一种"巨大的"、柔软而温暖的"枕头",也可以说是充满了房间的五颜六色的安全城堡。将一些简单的垫子放在一个游戏区或小屋里,这个柔软的结构化的环     

Presence of Clostridium perfringens in meat-based preparations in public food services in central San Jose, Costa Rica

In Costa Rica there are a large number of public food services distributed along the country, where a considerable number of people eat daily. Clostridium perfringens is a bacteria associated with foodborne illness related, especially, to meat products kept for long time at temperatures under 70 degrees C. The aim of this study was to evaluate the public food services that use water baths for keeping food hot in order to establish the presence of C. perfringens in cooked bovine meat dishes and to evaluate the enterotoxigenic capacity of the strains isolated. 81 samples of cooked bovine meat plates coming from 27 public food services, located in the Central County of San José were analyzed. The methodology described by Labbe & Harmon for the isolation of C. perfringens was used in 10 g of sample. Also, the enterotoxigenic capacity of the strains was evaluated using the passive-reverse-latex-agglutination assay from Oxoid. From the 27 public food services analyzed, eight (30%) were positive in the three samplings done, nine (33%) were positive in one or two occasions, and ten (37%) were negative all times. This implies that in 17 (63%) of the establishments studied, the bacteria was isolated at least once. From the 81 preparations studied, 37 (46%) were positive for the bacteria. The temperatures at which food was kept varied from 56 to 82 degrees C, with an average of 68.7 degrees C. From the 37 strains identified as C. perfringens, 12 (32%) were positive for enterotoxin. In conclusion, the presence of C. perfringens in bovine meat dishes, maintained in water baths, represents an important risk for public health, and the temperature at which the preparation is kept is critical for the multiplication of the bacteria.     

Vitamins and minerals from sardine in tomato sauce, from the Mexican Pacific fish zones

Sardine is a sea food widely consumed in Mexico due to it's abundance and very low price. Its content in vitamins, minerals and chemical composition were evaluated in its canned presentation in tomato sauce. Samples proceeded from 3 fishery areas of the Mexican Pacific: (L1) Baja California Sur, (L2) Sonora and (L3) Sinaloa. The proximal chemical analysis was carried out by the AOAC methods; mineral content (Ca, Mg, Na, K, Fe, Zn, Cu, Cd, Cr, Pb) was determined by atomic absorption spectrophotometry and vitamins A, B1, B2 and niacin were quantified by HPLC. Results showed a high moisture content from 69 to 82%, ether extract ranged between 7.8% (L2) and 10.2% (L3) and crude protein content between 10.6% (L3) and 14.6% (L1). Vitamin A (IU/100 g) was similar for all samples: L1 (63-66); thiamin (mg/100 g) was high in L1 (0.13) and low in L3 (0.09); riboflavin was high in L1 (0.15) and showed values of 0.13 for both L2 and L3; niacin content was high in all samples: L1 (2.24), L2 (1.48) and L3 (1.75). Minerals were abundant (mg/100 g) in Na, K, and P; L1 showed a great variation for Na (363-636) compared with L2 and L3 (250); K was very variable among the samples: L1 (597), L2 (100) and L3 (57). Phosphorous and magnesium had small variations: P (229, 243 and 212) and Mg (28, 23 and 23) for L1, L2 and L3. Iron was more abundant in L1 (5.5) and L3 (4.3); Zn was higher in L2 (3.4) and similar in L1 (2.5) and L3 (2.2). Copper showed a great variation in L2 (0.21-0.48) but the averages were similar (0.37, 0.35, 0.33, for L1, L2 and L3 respectively). Finally, heavy metal content was lower than 0.002 mg/100 g. In conclusion, there are some variation in Ca, Na, K, thiamin and niacin content in canned sardine with tomato sauce, depending upon the fishing area.