In the present study, inclusion of mealworm (Tenebrio molitor L.) powder into bread doughs at 5 and 10% substitution level of soft wheat (Triticum aestivum L.) flour was tested to produce protein fortified breads. The addition of mealworm powder (MP) did not negatively affect the technological features of either doughs or breads. All the tested doughs showed the same leavening ability, whereas breads containing 5% MP showed the highest specific volume and the lowest firmness. An enrichment in protein content was observed in experimental breads where the highest values for this parameter were recorded in breads containing 10% MP. Breads fortified with 10% MP also exhibited a significant increase in the content of free amino acids, and especially in the following essential amino acids: tyrosine, methionine, isoleucine, and leucine. By contrast, no differences in nutritional quality of lipids were seen between fortified and control breads. Results of sensory analyses revealed that protein fortification of bread with MP significantly affected bread texture and overall liking, as well as crust colour, depending on the substitution level. Overall, proof of concept was provided for the inclusion of MP into bread doughs started with different leavening agents (sourdough and/or baker’s yeast), at 5 or 10% substitution level of soft wheat flour. Based on the Technology Readiness Level (TRL) scale, the proposed bread making technology can be situated at level 4 (validation in laboratory environment), thus suggesting that the production of breads with MP might easily be scaled up at industrial level. However, potential spoilage and safety issues that need to be further considered were highlighted.

Damage-associated molecular patterns (DAMPs) are molecules that can be actively or passively released by injured tissues and that activate the immune system. Here we show that nicotinate phosphoribosyltransferase (NAPRT), detected by antibody-mediated assays and mass spectrometry, is an extracellular ligand for Toll-like receptor 4 (TLR4) and a critical mediator of inflammation, acting as a DAMP. Exposure of human and mouse macrophages to NAPRT activates the inflammasome and NF-κB for secretion of inflammatory cytokines. Furthermore, NAPRT enhances monocyte differentiation into macrophages by inducing macrophage colony-stimulating factor. These NAPRT-induced effects are independent of NAD-biosynthetic activity, but rely on NAPRT binding to TLR4. In line with our finding that NAPRT mediates endotoxin tolerance in vitro and in vivo, sera from patients with sepsis contain the highest levels of NAPRT, compared to patients with other chronic inflammatory conditions. Together, these data identify NAPRT as a endogenous ligand for TLR4 and a mediator of inflammation.

Diadenosine tetraphosphate (Ap4A) is a dinucleotide found in both prokaryotes and eukaryotes. In bacteria, its cellular levels increase following exposure to various stress signals and stimuli, and its accumulation is generally correlated with increased sensitivity to a stressor(s), decreased pathogenicity, and enhanced antibiotic susceptibility. Ap4A is produced as a by-product of tRNA aminoacylation, and is cleaved to ADP molecules by hydrolases of the ApaH and Nudix families and/or by specific phosphorylases. Here, considering evidence that the recombinant protein YqeK from Staphylococcus aureus copurified with ADP, and aided by thermal shift and kinetic analyses, we identified the YqeK family of proteins (COG1713) as an unprecedented class of symmetrically cleaving Ap4A hydrolases. We validated the functional assignment by confirming the ability of YqeK to affect in vivo levels of Ap4A in B. subtilis. YqeK shows a catalytic efficiency toward Ap4A similar to that of the symmetrically cleaving Ap4A hydrolases of the known ApaH family, although it displays a distinct fold that is typical of proteins of the HD domain superfamily harboring a diiron cluster. Analysis of the available 3D structures of three members of the YqeK family provided hints to the mode of substrate binding. Phylogenetic analysis revealed the occurrence of YqeK proteins in a consistent group of Gram-positive bacteria that lack ApaH enzymes. Comparative genomics highlighted that yqeK and apaH genes share a similar genomic context, where they are frequently found in operons involved in integrated responses to stress signals. IMPORTANCE Elevation of Ap4A level in bacteria is associated with increased sensitivity to heat and oxidative stress, reduced antibiotic tolerance, and decreased pathogenicity. ApaH is the major Ap4A hydrolase in gamma- and betaproteobacteria and has been recently proposed as a novel target to weaken the bacterial resistance to antibiotics. Here, we identified the orphan YqeK protein family (COG1713) as a highly efficient Ap4A hydrolase family, with members distributed in a consistent group of bacterial species that lack the ApaH enzyme. Among them are the pathogens Staphylococcus aureus, Streptococcus pneumoniae, and Mycoplasma pneumoniae. By identifying the player contributing to Ap4A homeostasis in these bacteria, we disclose a novel target to develop innovative antibacterial strategies.

Damage-associated molecular patterns (DAMPs) are molecules that can be actively or passively released by injured tissues and that activate the immune system. Here we show for the first time that the NAD biosynthetic enzyme nicotinate phosphoribosyltransferase (NAPRT), the rate-limiting enzymes in the intracellular synthesis of NAD from nicotinic acid, is physiologically present in human sera, where it acts as a novel DAMP. We detected NAPRT in plasma/sera from human donors by antibody-mediated luminex assays and mass spectrometry. Exposure of human and mouse macrophages to NAPRT triggers activation of ERK1/2, phosphorylation of IKKα/β and nuclear translocation of the p65 subunit of the NF-kB complex, with synthesis and secretion of inflammatory cytokines, including IL-1β, IL-8, TNFα and CCL3. Furthermore, NAPRT enhances monocyte differentiation into macrophages, by inducing macrophage colony-stimulating factor. These effects are independent of the NAPRT catalytic activity, but rely on the protein’s binding to TLR4, as demonstrated by showing direct in vitro interaction and by the in vivo lack of NAPRT effects in TLR4−/− macrophages. In line with the finding that NAPRT mediates endotoxin tolerance, sera from patients with sepsis or septic shock contain the highest levels of circulating NAPRT, compared to other chronic inflammatory conditions, including cancer. Importantly, patients with serum NAPRT >15 ng/ml are characterized by a worse clinical outcome, compared to the counterparts. Together, these data identify NAPRT as a novel endogenous ligand for TLR4 and a critical mediator of inflammation.

Several health benefits are related to the administration of nicotinamide riboside (NR), a form of Vitamin B3, and its precursors nicotinamide mononucleotide (NMN) and NAD + . Therefore, considerable interest is currently devoted to the potential therapeutic value of their supplementation, thus justifying scientific studies on the distribution of these molecules in foods and beverages. In this study, the three vitamers were quantitatively analyzed in ten craft beers for the first time. All beers from different commercial S. cerevisiae strains contained NAD + . NR, NMN and NAD + were mostly present in beers produced with Saccharomyces cerevisiae strain US-05. Interestingly, the three vitamers were not detectable in beers produced with a commercial strain of Saccharomyces pastorianus. Data from laboratory-scale beer production using S. cerevisiae strain US-05 showed that the addition of hops during the fermentation process significantly increased NR production. The rapid increase in NR formation only occurred if both hops and yeast were present, and the burst was also confirmed in fermentations trials performed with S. cerevisiae strain CBS1171 T and by replacing wort with YPD medium. The experimental model proposed in the present study can serve as baseline for further research aimed at investigating the yeast-hop interaction at metabolic and molecular levels.In addition to highlighting the potentialities of microorganisms to act as biological factories for beneficial molecules to humans, these findings open new intriguing perspectives for the development of innovative fermented foods naturally enriched in NR and its precursors.