No abstract

Gamma-aminobutyric acid (GABA) plays a key role in mammals as the major inhibitory neurotransmitter of the central nervous system. Although GABA may not be able to cross the human blood-brain barrier, it was approved as a food ingredient because of its benefits to the host after oral administration including anti-hypertensive, anti-depressant and anti-inflammatory activities. Considering the current trend toward the development of new functional and natural products and that microbial fermentation is one of the most promising methods to produce this non-protein amino acid, the in situ production of GABA through fermentation of strawberry and blueberry juices by the efficient GABA producer strain, Levilactobacillus brevis (formerly known as Lactobacillus brevis) CRL 2013, was evaluated. A high GABA production (262 mM GABA) was obtained after fermenting strawberry juice supplemented with yeast extract for 168 h, being GABA yield significantly higher in strawberry juices than in the blueberry ones. Thus, GABA-enriched fermented strawberry juice (FSJ) was selected to carry out in vivo and in vitro studies. The in vitro functional analysis of the GABA-enriched FSJ demonstrated its ability to significantly decrease the expression of cox-2 gene in LPS stimulated RAW 264.7 macrophages. In addition, in vivo studies in mice demonstrated that both, L. brevis CRL 2013 and the GABA-enriched FSJ were capable of reducing the levels of peritoneal, intestinal and serum TNF-α, IL-6, and CXCL1, and increasing IL-10 and IFN-γ in mice exposed to an intraperitoneal challenge of LPS. Of note, the GABA-enriched FSJ was more efficient than the CRL 2013 strain to reduce the pro-inflammatory factors and enhance IL-10 production. These results indicated that the CRL 2013 strain exerts anti-inflammatory effects in the context of LPS stimulation and that this effect is potentiated by fermentation. Our results support the potential use of L. brevis CRL 2013 as an immunomodulatory starter culture and strawberry juice as a remarkable vegetable matrix for the manufacture of GABA-enriched fermented functional foods capable of differentially modulating the inflammatory response triggered by TLR4 activation.

Proteolytic starter cultures with intrinsic immunomodulatory activities are desirably features for the development of functional foods, which would significantly reduce the cost of their production (one-strain starter) having an additional beneficial effect on the host. In this work, Lactobacillus delbrueckii strains were selected according to their ability to efficiently hydrolyse β-casein and to modulate the immune system. Among 36 strains evaluated, the highest proteolytic activities were found for L. delbrueckii subsp. lactis CRL581 and L. delbrueckii subsp. bulgaricus CRL656. The immunomodulatory effect of both strains and their β-casein hydrolysates (CRL581 and CRL656 hydrolysates, respectively) were studied in a murine model. Balb/c mice were fed lactobacilli or their hydrolysates for three days. One day after the last lactobacilli or hydrolysate treatments, mice were challenged with the Toll-like receptor 3 (TLR3) agonist poly(I:C) by intraperitoneal injection. Before and after poly(I:C) challenge the phagocytic and microbicidal activity of peritoneal macrophages, intestinal immunoglobulin A (IgA), cytokine profile, and histological analysis of the intestine were analysed. L. delbrueckii subsp. lactis CRL581 significantly increased the activation of peritoneal macrophages as well as the levels of intestinal IgA, interleukin (IL)-10 and interferon (IFN)-γ when compared to untreated controls. In addition, the CRL581 strain was able to significantly reduce the intestinal inflammatory damage triggered by TLR3 activation. L. delbrueckii CRL581 increased the levels of IL-10, IFN-γ and IFN-β, and reduced tumour necrosis factor alpha and IL-6 concentrations in the intestine of poly(I:C)-challenged mice. No immunomodulatory effects were observed for the CRL656 strain or for the CRL581 or CRL656 hydrolysates. The results of this work show that the technologically relevant and high proteolytic strain L. delbrueckii CRL581 is able to beneficially modulate the intestinal innate antiviral immune response. Although further studies with the CRL581 strain are required to corroborate and deepen its immunological effects, this bacterium is an interesting alternative for the development of new functional foods with antiviral capabilities.

Abstract2-Hydroxy-4,6-dimethylpyridine-3-carbonitrile and 2-chloro-4,6-dimethylpyridine-3-carbonitrile compounds have been studied from a theoretical point of view in order to know their structural and vibrational properties in gas and aqueous solution phases by means of Density Functional Theory (DFT) calculations. The stable structures in both media were optimized by using the hybrid B3LYP/6-31G * method and the solvent effects in aqueous solution were studied by using the integral equation formalism of the polarizable continuum model (IEFPCM) employing the selfconsistent reaction field (SCRF) method. Detailed vibrational analyses for both compounds in the two phases were performed combining the DFT calculations with Pulay's Scaled Quantum Mechanics Force Field (SQMFF) methodology. The different interactions for both compounds were analyzed by means of the bond orders, atomic charges, solvation energies, dipole moments, molecular electrostatic potentials and force constants parameters. The nature of the interactions was studied by using different descriptors.

Background 6S RNA is a regulator of cellular transcription that tunes the metabolism of cells. This small non-coding RNA is found in nearly all bacteria and among the most abundant transcripts. Lactic acid bacteria (LAB) constitute a group of microorganisms with strong biotechnological relevance, often exploited as starter cultures for industrial products through fermentation. Some strains are used as probiotics while others represent potential pathogens. Occasional reports of 6S RNA within this group already indicate striking metabolic implications. A conceivable idea is that LAB with 6S RNA defects may metabolize nutrients faster, as inferred from studies of Echerichia coli. This may accelerate fermentation processes with the potential to reduce production costs. Similarly, elevated levels of secondary metabolites might be produced. Evidence for this possibility comes from preliminary findings regarding the production of surfactin in Bacillus subtilis, which has functions similar to those of bacteriocins. The prerequisite for its potential biotechnological utility is a general characterization of 6S RNA in LAB. Results We provide a genomic annotation of 6S RNA throughout the Lactobacillales order. It laid the foundation for a bioinformatic characterization of common 6S RNA features. This covers secondary structures, synteny, phylogeny, and product RNA start sites. The canonical 6S RNA structure is formed by a central bulge flanked by helical arms and a template site for product RNA synthesis. 6S RNA exhibits strong syntenic conservation. It is usually flanked by the replication-associated recombination protein A and the universal stress protein A. A catabolite responsive element was identified in over a third of all 6S RNA genes. It is known to modulate gene expression based on the available carbon sources. The presence of antisense transcripts could not be verified as a general trait of LAB 6S RNAs. Conclusions Despite a large number of species and the heterogeneity of LAB, the stress regulator 6S RNA is well-conserved both from a structural as well as a syntenic perspective. This is the first approach to describe 6S RNAs and short 6S RNA-derived transcripts beyond a single species, spanning a large taxonomic group covering multiple families. It yields universal insights into this regulator and complements the findings derived from other bacterial model organisms.

In this work, the structural and vibrational properties of 1-5-(difluoromethyl-1H-pyrrol-2-yl-) ethanone (DFPE) were studied by using the hybrid B3LYP/6-31G* method. The properties were analyzed and compared with those obtained for 1-(1H-pyrrol-2-yl) ethanone (PE) and 1-(5-(trifluoromethyl)-1H-pyrrol-2-yl) ethanone (TFPE). The theoretical 1 H-NMR, 13 C-NMR and 19 F-NMR chemical shifts for DFPE were predicted by using the B3LYP/6-311++G** approach with the GIAO and CGST methods showing the three spectra good concordances with the corresponding experimental ones. A complete assignment of the vibrational spectra was presented.

In this research, structures and properties of monomer and two dimers (1 and 2) of inhibitor of cytochrome P450 enzymes, 1-Aminobenzotriazole (ABT) have been studied by using functional hybrid B3LYP/6-311++G** calculations. The very good correlations observed between theoretical and experimental 1H-, 13C-NMR, FT-IR and FT-Raman spectra suggest that C-H···N interactions of dimeric species should be expected in the solid phase, as was observed in the experimental crystalline structure of a quinolin benzotriazole derivative. NBO and AIM calculations suggest that dimer 2 with inverted positions of its monomers could be present in the solid phase because it evidence higher stabilities in both media. On the other hand, frontier orbitals studies support a higher reactivity of dimer 2 of ABT higher than the monomer and dimer 1, for which, the presence of dimer 2 containing N-NH2 groups in ABT could justify the biological activities observed for this species with gap values between 4.5933 and 4.8164 eV different from antiviral agents containing the C-NH2 moiety, as amantadine and chloroquine whose gap values are around 4.3012-4.1116 eV. Finally, the presence of bands of monomer and of both dimers are predicted in the vibrational spectra and, hence, its completes assignments have been performed. The scaled force constants for the three studied species are also reported.