Rapid diffusion method for physicochemical characterization of metal ligands in soils and sediments

A diffusion method is described that allows preliminary characterization of metals in soils and sediments while minimizing the potential for alteration of metal form. In addition, examples of the application of the method to model compounds of Pu in the soil are given. (ERB

Difference in metabolite levels between photoautotrophic and photomixotrophic cultures of Synechocystis sp. PCC 6803 examined by capillary electrophoresis electrospray ionization mass spectrometry

Capillary electrophoresis mass spectrometry (CE/MS) was applied for the comprehensive survey of changes in the amounts of metabolites upon the shift from photoautotrophic to photomixotrophic conditions in Synechocystis sp. PCC 6803. When glucose was added to the photoautotrophically grown culture, the increase in the metabolites for the oxidative pentose phosphate (OPP) pathway and glycolysis, together with the decrease in those for the Calvin cycle, was observed. Concomitantly, the increase in respiratory activity and the decrease in photosynthetic activity took place in the wild-type cells. In the pmgA-disrupted mutant that shows growth inhibition under photomixotrophic conditions, lower enzymatic activities of the OPP pathway and higher photosynthetic activity were observed, irrespective of trophic conditions. These defects brought about metabolic disorders such as a decrease in ATP and NADPH contents, a failure in the activation of respiratory activity, and the aberrant accumulation of isocitrate under photomixotrophic but not under photoautotrophic conditions. A delicate balancing of the carbon flow between the Calvin cycle and the OPP pathway seems indispensable for growth specifically under photomixotrophic conditions and PmgA is likely to be involved in the regulation

Development of a novel smoke-flavoured salmon product by sodium replacement using water vapour permeable bags

This is the peer reviewed version of the following article: Rizo Parraga, Arancha Maria, Fuentes López, Ana, Barat Baviera, José Manuel, Fernández Segovia, Isabel. (2018). Development of a novel smoke-flavoured salmon product by sodium replacement using water vapour permeable bags.Journal of the Science of Food and Agriculture, 98, 7, 2721-2728. DOI: 10.1002/jsfa.8767, which has been published in final form at http://doi.org/ 10.1002/jsfa.8767. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] BACKGROUND: Food manufacturers need to reduce sodium contents to meet consumer and public health demands. In this study the use of sodium-free (SF) salt and KCl to develop a novel smoke-flavoured salmon product with reduced sodium content was evaluated. Fifty percent of NaCl was replaced with 50% of SF salt or 50% KCl in the salmon smoke-flavouring process carried out using water vapour permeable bags. RESULTS: Triangle tests showed that samples with either SF salt or KCl were statistically similar to the control samples (100% NaCl). Since no sensorial advantage in using SF salt was found compared with KCl and given the lower price of KCl, the KCl-NaCl samples were selected for the next phase. The changes of physicochemical and microbial parameters in smoke-flavoured salmon during 42 days showed that partial replacement of NaCl with KCl did not significantly affect the quality and shelf-life of smoke-flavoured salmon, which was over 42 days. CONCLUSION: Smoke-flavoured salmon with 37% sodium reduction was developed without affecting sensory features and shelf-life. This is an interesting option for reducing sodium content in such products to help meet the needs set by both health authorities and consumers.We gratefully acknowledge the support of Tub-Ex Aps (Taars, Denmark) for suppling the water vapour permeable bags and for providing all of the necessary technical information. Arantxa Rizo thanks the Universitat Politecnica de Valencia for the FPI grant.Rizo Parraga, AM.; Fuentes López, A.; Barat Baviera, JM.; Fernández Segovia, I. (2018). Development of a novel smoke-flavoured salmon product by sodium replacement using water vapour permeable bags. Journal of the Science of Food and Agriculture. 98(7):2721-2728. https://doi.org/10.1002/jsfa.8767S2721272898

Reconstruction and analysis of genome-scale metabolic model of a photosynthetic bacterium

<p>Abstract</p> <p>Background</p> <p><it>Synechocystis </it>sp. PCC6803 is a cyanobacterium considered as a candidate photo-biological production platform - an attractive cell factory capable of using CO₂and light as carbon and energy source, respectively. In order to enable efficient use of metabolic potential of <it>Synechocystis </it>sp. PCC6803, it is of importance to develop tools for uncovering stoichiometric and regulatory principles in the <it>Synechocystis </it>metabolic network.</p> <p>Results</p> <p>We report the most comprehensive metabolic model of <it>Synechocystis </it>sp. PCC6803 available, <it>i</it>Syn669, which includes 882 reactions, associated with 669 genes, and 790 metabolites. The model includes a detailed biomass equation which encompasses elementary building blocks that are needed for cell growth, as well as a detailed stoichiometric representation of photosynthesis. We demonstrate applicability of <it>i</it>Syn669 for stoichiometric analysis by simulating three physiologically relevant growth conditions of <it>Synechocystis </it>sp. PCC6803, and through <it>in silico </it>metabolic engineering simulations that allowed identification of a set of gene knock-out candidates towards enhanced succinate production. Gene essentiality and hydrogen production potential have also been assessed. Furthermore, <it>i</it>Syn669 was used as a transcriptomic data integration scaffold and thereby we found metabolic hot-spots around which gene regulation is dominant during light-shifting growth regimes.</p> <p>Conclusions</p> <p><it>i</it>Syn669 provides a platform for facilitating the development of cyanobacteria as microbial cell factories.</p