35 research outputs found

    Extracellular DNA secreted in yeast cultures is metabolism-specific and inhibits cell proliferation

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    Extracellular DNA (exDNA) can be actively released by living cells and different putative functions have been attributed to it. Further, homolo-gous exDNA has been reported to exert species-specific inhibitory effects on several organisms. Here, we demonstrate by different experimental evidence, including 1H-NMR metabolomic fingerprint, that the growth rate decline in Saccharomyces cerevisiae fed-batch cultures is determined by the accumula-tion of exDNA in the medium. Sequencing of such secreted exDNA represents a portion of the entire genome, showing a great similarity with extrachromo-somal circular DNA (eccDNA) already reported inside yeast cells. The recov-ered DNA molecules were mostly single strands and specifically associated to the yeast metabolism displayed during cell growth. Flow cytometric analysis showed that the observed growth inhibition by exDNA corresponded to an arrest in the S phase of the cell cycle. These unprecedented findings open a new scenario on the functional role of exDNA produced by living cells

    WHOLE-GENOME RE-SEQUENCING OF TWO TOMATO LANDRACES REVEALS SEQUENCE VARIATIONS UNDERPINNING KEY ECONOMICALLY IMPORTANT TRAITS

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    In the post-genomic era, one of the major challenges is the identification of alleles directly responsible for phenotype variation among different genotypes within the same species. Tomato is a model crop for understanding the development and ripening of climacteric fleshy fruits, and it is also known to be an important source of health-promoting compounds. In addition, cultivated tomato germplasm shows a high phenotypic variation despite its very low genetic diversity. Toward the identification of sequence variations responsible for stress tolerance, high fruit quality and long shelf life, we re-sequenced the genomes of two traditional landraces grown in the Campania region (Southern Italy). Crovarese, belonging to the Corbarino type (COR), and Lucariello (LUC) are typically grown under low water regimes and produce highly appreciated fruits, which can be stored up to 4-8 months. We generated 65.8M and 56.4M of paired-end 30-150 bp reads with an average insert size of 380 bp (± 52bp) and 364 bp (± 49bp) for COR and LUC, respectively. A referenceguided assembly was performed using 'Heinz 1706' as a reference genome. We estimated a mean coverage depth of ~15X for COR and 13X for LUC. Comparing the genomes of COR and LUC with that of 'Heinz 1706' we found a similar distribution of SNPs (68.8% vs. 69.9%, respectively), small deletions (8.9% vs. 8.6%) and small insertions (22.1% vs. 21.3%). Through a de novo assembly of the unmapped reads we identified 29 and 36 new contigs in COR and LUC, respectively. The new contigs could be assigned to the chromosomes thanks to the use of a splitread approach. On average, the contigs inserted in COR were 654bp, whereas those inserted in LUC were 616bp. Using custom RNA-seq data, a total of 43054 and 44576 gene loci were annotated in COR and LUC, corresponding to 62369 and 65094 transcripts, respectively. Among the genes showing a similar structure in COR and LUC compared to 'Heinz 1706', we identified ~2000 and 1700 SNPs causing potentially disruptive effects on the function of 1371 and 1201 genes in COR and LUC, respectively. Interesting GO categories highly represented in genes affected by sequence changes were identified. Major variations were present in stress-responsive genes as well as in fruit quality and development-related genes. From a practical perspective, the identified SNPs and InDels are candidate polymorphisms to track DNA variations associated to key traits of economic interest

    EFFECT OF THE ADDITION OF FRUIT JUICES ON GRAPE MUST FOR NATURAL BEVERAGE PRODUCTION

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    The consumer attention for products with healthy properties is increased in time, and fruit juices, for their ease of consumption, can satisfy this demand providing them bioactive compounds.The grape juice has numerous health benefits demonstrated by several studies such as, among other, the antioxidant activities and the positive functions of their phenolic compounds. This workis aimed at blending grape and others fruits in a new fruit juice made only with natural ingredients of local production. The grape juice (cv Barbera) has substituted water and its percentagewas fixed (70%). It was mixed with apple (cv Golden delicious), pear (cv Williams) and peach (cv Red Haven) juices to obtain 25 different prototypes. In each of these at least two fruit juices werepresent and added in a percentage variable from 0 to 25%, with a step of 5%. The objectives of this study were to check the feasibility of the mixing process and the evaluation of the samplesoverall pleasantness. Other sensory aspects of samples were also evaluated by consumers with a JAR (just-aboutright) structured scale. The results didn’t reveal particular technological problems regarding the blending process. The Brix mean value of the samples was about 15.3, with a significant reductioncompared to that of the grape juice (about 19). The pH mean value of the samples (3.44) was significantly higher than that of the grape juice (3.36). The titrable acidity and the antioxidant capacitymean value of the samples was, namely, 6.22 g L-1 and 535.18 mg L-1. The penalty analysis of the liking test pointed out the importance of the persistence in mouth. The overall pleasantnesswas significantly (p≀0,01) positively correlated with the °Brix/acid ratio (r=0.54) and samples with the highest percentage of pear juice were generally preferred
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