Impact of cooking methods of red-skinned onion on metabolic transformation of phenolic compounds and gut microbiota changes

Herein, we investigated the stability and bioaccessibility of phenolics in differently cooked red-skinned onion (RSO) and consequently their impact on the gut microbiota and metabolism of phenolics. In fact, the different processes used to cook vegetables can modify and re-arrange the molecular profiles of bioactive compounds, such as phenolics in phenolic-rich vegetables, such as RSO. Fried and grilled RSO were compared to raw RSO and a blank control and subjected to oro-gastro-intestinal digestion and subsequent colonic fermentation. For upper gut digestion, the INFOGEST protocol was used, and for lower gut fermentation, a short-term batch model, namely, MICODE (multi-unit in vitro colon gut model), was employed. During the process, phenolic compound profile (through high-resolution mass spectrometry) and colon microbiomics (qPCR of 14 core taxa) analyses were performed. According to the results, the degradation driven by the colon microbiota of RSO flavonols resulted in the accumulation of three main metabolites, i.e., 3-(3 '-hydroxyphenyl)propanoic acid, 3-(3 '-hydroxyphenyl)acetic acid and 3-(3 ',4 '-dihydroxyphenyl)acetic acid. Also, colonic fermentation of raw onions resulted in a substantial increase in beneficial taxa, which was larger compared to the heat-treated onions, particularly Lactobacillales and beneficial clostridia. Also, a higher level of inhibition of opportunistic bacteria was seen for the raw onion samples, namely, Clostridium perfringens group and Escherichia coli. Thus, our results showed that RSO, and especially the raw one, is an excellent dietary source of flavonols that are strongly metabolized by gut bacteria and can positively modulate the gut microbiota. Although additional in vivo studies are necessary, this work is one of the first to explore how RSO processed with different cooking methods can differently impact the phenolic metabolism and microbiota composition in the large intestine of humans, fine-tuning the antioxidant nature of foods

An integrated peptidomics and in silico approach to identify novel anti-diabetic peptides in parmigiano-reggiano cheese

Inhibition of key metabolic enzymes linked to type-2-diabetes (T2D) by food-derived compounds is a preventive emerging strategy in the management of T2D. Here, the impact of Parmigiano- Reggiano (PR) cheese peptide fractions, at four different ripening times (12, 18, 24, and 30 months), on the enzymatic activity of α-glucosidase, α-amylase, and dipeptidyl peptidase-IV (DPPIV) as well as on the formation of fluorescent advanced glycation end-products (fAGEs) was assessed. The PR peptide fractions were able to inhibit the selected enzymes and fAGEs formation. The 12-month-ripening PR sample was the most active against the three enzymes and fAGEs. Mass spectrometry analysis enabled the identification of 415 unique peptides, 54.9% of them common to the four PR samples. Forty-nine previously identified bioactive peptides were found, mostly characterized as angiotensin-converting enzyme-inhibitors. The application of an integrated approach that combined peptidomics, in silico analysis, and a structure–activity relationship led to an efficient selection of 6 peptides with potential DPP-IV and α-glucosidase inhibitory activities. Peptide APFPE was identified as a potent novel DPP-IV inhibitor (IC50 = 49.5 ± 0.5 μmol/L). In addition, the well-known anti-hypertensive tripeptide, IPP, was the only one able to inhibit the three digestive enzymes, highlighting its possible new and pivotal role in diabetes management

Cultivable microbial diversity, peptide profiles, and bio-functional properties in Parmigiano Reggiano cheese

Introduction: Lactic acid bacteria (LAB) communities shape the sensorial and functional properties of artisanal hard-cooked and long-ripened cheeses made with raw bovine milk like Parmigiano Reggiano (PR) cheese. While patterns of microbial evolution have been well studied in PR cheese, there is a lack of information about how this microbial diversity affects the metabolic and functional properties of PR cheese. Methods: To fill this information gap, we characterized the cultivable fraction of natural whey starter (NWS) and PR cheeses at different ripening times, both at the species and strain level, and investigated the possible correlation between microbial composition and the evolution of peptide profiles over cheese ripening. Results and discussion: The results showed that NWS was a complex community of several biotypes belonging to a few species, namely, Streptococcus thermophilus, Lactobacillus helveticus, and Lactobacillus delbrueckii subsp. lactis. A new species-specific PCR assay was successful in discriminating the cheese-associated species Lacticaseibacillus casei, Lacticaseibacillus paracasei, Lacticaseibacillus rhamnosus, and Lacticaseibacillus zeae. Based on the resolved patterns of species and biotype distribution, Lcb. paracasei and Lcb. zeae were most frequently isolated after 24 and 30 months of ripening, while the number of biotypes was inversely related to the ripening time. Peptidomics analysis revealed more than 520 peptides in cheese samples. To the best of our knowledge, this is the most comprehensive survey of peptides in PR cheese. Most of them were from β-caseins, which represent the best substrate for LAB cell-envelope proteases. The abundance of peptides from β-casein 38–88 region continuously increased during ripening. Remarkably, this region contains precursors for the anti-hypertensive lactotripeptides VPP and IPP, as well as for β-casomorphins. We found that the ripening time strongly affects bioactive peptide profiles and that the occurrence of Lcb. zeae species is positively linked to the incidence of eight anti-hypertensive peptides. This result highlighted how the presence of specific LAB species is likely a pivotal factor in determining PR functional properties

Resistance of European spring 2-row barley cultivars to Pyrenophora graminea and detection of associated loci

Pyrenophora graminea is the seed-borne pathogen causal agent of barley leaf stripe disease. In this work, we screened a collection of 206 spring two-row barley cultivars from Europe for their resistance to the fungal pathogen. Artificial inoculation with the highly virulent isolate Dg2 revealed a continuous variation for the incidence of infection, with few highly resistant or highly susceptible genotypes. On average, old cultivars showed higher resistance than the more modern ones. Genome- Wide Association Scan was performed by exploiting available molecular data for >4000 SNP markers and revealed a single, highly significant association on the short arm of chromosome 6H, in a genomic position where quantitative trait loci (QTL) for barley resistance to P. graminea were not detected before. Based on the last version of the reference barley genome, genes encoding for proteins with a kinase domain were suggested as candidates for the locus

Biodiversity of grapevines (Vitis vinifera L.) grown in the Province of Verona

PCR-based DNA microsatellite analysis has been applied to define the genetic relationships among 7 most representative grapevine cultivars grown in the province of Verona, 5 ancient grapevine and two varieties grown in different regions of Italy. For each variety three different clones or accessions were investigated to assess genotypical uniformity; in 5 cases we found out intravarietal dissimilarity. SSR data were used to create a distance matrix and then a polylogenetic tree. Results show a polygenetic relationship among some cultivated (Corvina, Rondinella, Molinara, Trebbiano di Soave-Verdicchio) and ancient (Dindarella-Pelara, Oseleta, Rossetta di montagna) varieties all grown in the Valpolicella hills, suggesting the possibility that their evolution occurred in the same area and with few common anchestors. Two situations of synonyms that had already described between Trebbiano di Soave and Verdicchio, and between Dindarella and Pelara, were confirmed by a molecular method as SSR analysis. Amplification of Trebbiano di Soave/Verdicchio locus VVMD36 yielded a fragment of 500 bp, this allele provides a fast and reliable tool to differentiate among Trebbiano grapevines.

Genome-Wide Association Mapping of Root Extension in a Collection of European Winter Barley Cultivars

Root extension in cereals is an extremely plastic trait exhibiting high variation in relation to the genetic background and to environmental conditions. The study of root system is particularly important in the Mediterranean area, where genetic improvement of drought tolerance on winter barley is a relevant breeding target. Here we aimed at exploring the natural genetic variation in root extension in a collection of European winter barley cultivars (67 two-rowed and 75 six-rowed, released between 1921 and 2006). For each genotype, three plants were grown in cylindrical pots (rhizotrons) with diameter of 10 cm and 50 cm height, filled with siliceous sand. Plants were collected at the 4 leaf stage (Zadocks stage 14), when roots were separated from shoots and scanned. The obtained images were analyzed by using the winRHIZO software to calculate the total root extension, as the sum of lengths of primary and secondary roots. The whole experiment was replicated three times, showing repeatability of 0.53. The same collection was previously genotyped for >7000 iSelect SNP markers, providing a powerful tool for association mapping of root traits. Genotype-phenotype association with the R-GAPIT package identified a significant genomic region on chromosome 5H-bin7, that has been scrutinized for candidate genes and alleles with a putative role in the trait under study

Draft Genome Sequence of Lactobacillus plantarum Lp90 Isolated from Wine

Contains fulltext : 155072.pdf (publisher's version ) (Open Access)Here, we describe the draft genome sequence and annotation of Lactobacillus plantarum strain Lp90, the first sequenced genome of a L. plantarum strain isolated from wine. This strain has a noticeable ropy phenotype and showed potential probiotic properties. The genome consists of 3,324,076 bp (33 contigs) and contains 3,155 protein coding genes, 34 pseudogenes, and 84 RNA genes

Proteomic characterization of the Rph15 barley resistance gene-mediated defence responses to leaf rust

Background Leaf rust, caused by the biotrophic fungal pathogen Puccinia hordei, is one of the most important foliar disease of barley (Hordeum vulgare) and represents a serious threat in many production regions of the world. The leaf rust resistance gene Rph15 is of outstanding interest for resistance breeding because it confers resistance to over 350 Puccinia hordei isolates collected from around the world. Molecular and biochemical mechanisms responsible for the Rph15 effectiveness are currently not investigated. The aim of the present work was to study the Rph15-based defence responses using a proteomic approach. Results Protein pattern changes in response to the leaf rust pathogen infection were investigated in two barley near isogenic lines (NILs), Bowman (leaf rust susceptible) and Bowman-Rph15 (leaf rust resistant), differing for the introgression of the leaf rust resistance gene Rph15. Two infection time points, 24 hours and four days post inoculation (dpi), were analysed. No statistically significant differences were identified at the early time point, while at 4 dpi eighteen protein spots were significantly up or down regulated with a fold-change equal or higher than two in response to pathogen infection. Almost all the pathogen-responsive proteins were identified in the Bowman-Rph15 resistant NIL. Protein spots were characterized by LC-MS/MS analysis and found to be involved in photosynthesis and energy metabolism, carbohydrate metabolism, protein degradation and defence. Proteomic data were complemented by transcriptional analysis of the respective genes. The identified proteins can be related to modulation of the photosynthetic apparatus components, re-direction of the metabolism to sustain defence responses and deployment of defence proteins. Conclusions The identification of leaf rust infection-modulated defence responses restricted to the resistant NIL support the hypothesis that basal defence responses of Bowman, but not the Rph15 resistance gene-based ones, are suppressed or delayed by pathogen effectors to levels below the detection power of the adopted proteomic approach. Additionally, Rph15-mediated resistance processes identified mainly resides on a modulation of primary metabolism, affecting photosyntesis and carbohydrate pool