Suchergebnisse

This work reports on the production and characterization of agar-based extracts from the seaweed Gelidium sesquipedale by means of simple protocols based on hot water and sonication treatments. The combination of sonication with the hot water treatment reduced 4-fold the extraction time without significantly affecting the extraction yield (ca. 10–12%) and the extracts' properties. Apart from agar, the extracts contained proteins, polyphenols and minerals, which conferred them high antioxidant capacity and led to the production of brownish softer gels. The application of an alkali pre-treatment yielded almost pure agars, with higher molecular weights and crystallinities than commercial agar, resulting in stiffer gels. However, the partial digestion of agar by the alkali led to low extraction yields (ca. 2–3%). These results show the efficiency of the combined heat and sonication method to generate cost-effective agar-based extracts with potential applications within the food industry. ; This work was financially supported by the "Agencia Estatal de Investigación" and co-funded by the European Union's Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2). Marta Martinez-Sanz is recipient of a Juan de la Cierva (IJCI-2015-23389) contract from the Spanish Ministry of Economy, Industry and Competitiveness.

The relationship between secondary metabolism and infection in pathogenic fungi has remained largely elusive. The genus Penicillium comprises a group of plant pathogens with varying host specificities and with the ability to produce a wide array of secondary metabolites. The genomes of three Penicillium expansum strains, the main postharvest pathogen of pome fruit, and one Pencillium italicum strain, a postharvest pathogen of citrus fruit, were sequenced and compared with 24 other fungal species. A genomic analysis of gene clusters responsible for the production of secondary metabolites was performed. Putative virulence factors in P. expansum were identified by means of a transcriptomic analysis of apple fruits during the course of infection. Despite a major genome contraction, P. expansum is the Penicillium species with the largest potential for the production of secondary metabolites. Results using knockout mutants clearly demonstrated that neither patulin nor citrinin are required by P. expansum to successfully infect apples. Li et al. ( MPMI-12-14-0398-FI ) reported similar results and conclusions in their recently accepted paper. ; Work at L. González-Candelas' lab was partially supported by the Spanish Ministry of Economy and Innovation (Research Grants AGL-2008-04828-C03-02 and AGL2011-30519-C03-01) and by the Generalitat Valenciana, Spain(PROMETEO/2010/010 and PROMETEOII/2014/027). A.-R. Ballester is grateful to CSIC and the European Social Fund for her postdoctoral contract JAE-Doc. C. Selma-Lázaro is recipient of a FPI Predoctoral fellowship from the Spanish MICINN (BES-2012-054595). The T. Gabaldón group research is funded, in part, by a grant from the Spanish ministry of Economy and Competitiveness (BIO2012-37161), a Grant from the Qatar National Research Fund grant (NPRP 5-298-3-086), and a grant from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC (Grant Agreement n. ERC-2012- StG-310325).

Blue mould disease caused by Penicillium expansum infection is one of the most important diseases of pome fruit accounting for important economic losses. In the present study, the PeSte12 transcription factor gene was identified, and deletant mutants were produced by gene replacement. Knockout mutants showed a significant decrease of virulence during apple fruit infection. Virulence was affected by the maturity stage of the fruit (immature, mature and over-mature), and disease severity was notably reduced when the apples were stored at 0 °C. The ΔPeSte12 mutants resulted defective in asexual reproduction, producing less conidia, but this characteristic did not correlate with differences in microscopic morphology. In addition, the ΔPeSte12 mutants produced higher quantity of hydrogen peroxide than the wild type strain. Gene expression analysis revealed that PeSte12 was induced over time during apple infection compared to axenic growth, particularly from 2 dpi, reinforcing its role in virulence. Analysis of transcriptional abundance of several genes in ΔPeSte12 mutants showed that in most of the evaluated genes, PeSte12 seemed to act as a negative regulator during axenic growth, as most of them exhibited an increasing expression pattern along the time period evaluated. The highest expression values corresponded to detoxification, ATPase activity, protein folding and basic metabolism. Gene expression analysis during apple infection showed that 3 out of 9 analysed genes were up regulated; thus, PeSte12 seemed to exert a positive control to particular type of aldolase. These results demonstrate the PeSte12 transcription factor could play an important role in P. expansum's virulence and asexual reproduction. ; Authors are grateful to the Spanish Government for its financial support with the projects AGL2008-04828-C03-03, AGL2011-30519-C03-01, AGL2011-30519-C03-02 and AGL2011-30519-CO3-03 from the "Ministerio de Economía y Competitividad" (MINECO, Spain), the CERCA Programme/Generalitat de Catalunya and Generalitat Valenciana (PROMETEOII/2014/027).

Posidonia oceanica waste biomass has been valorised to produce extracts by means of different methodologies and their bioactive properties have been evaluated. Water-based extracts were produced using ultrasound-assisted and hot water methods and classified according to their ethanol-affinity (E1: ethanol soluble; E2: non-soluble). Moreover, a conventional protocol with organic solvents was applied, yielding E3 extracts. Compositional and structural characterization confirmed that while E1 and E3 extracts were mainly composed of minerals and lipids, respectively, E2 extracts were a mixture of minerals, proteins and carbohydrates. All the extracts showed remarkably high antioxidant capacity, which was not only related to phenolic compounds but also to the presence of proteins and polysaccharides. All E2 and E3 extracts inhibited the growth of several foodborne fungi, while only E3 extracts decreased substantially the infectivity of feline calicivirus and murine norovirus. These results show the potential of P. oceanica waste biomass for the production of bioactive extracts. ; This work was financially supported by the project GV/2018//149, the "Agencia Estatal de Investigación" and cofunded by the European Union's Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2). Marta Martinez-Sanz is recipient of a Juan de la Cierva (IJCI-2015-23389) contract from the Spanish Ministry of Economy, Industry and Competitiveness.