Ppx1 putative exopolyphosphatase is essential for polyphosphate accumulation in Lacticaseibacillus paracasei.

The linear polymer polyphosphate (poly-P) is present across all three domains of life and serves diverse physiological functions. The enzyme polyphosphate kinase (Ppk) is responsible for poly-P synthesis, whereas poly-P degradation is carried out by the enzyme exopolyphosphatase (Ppx). In many Lactobacillaceae, the Ppk-encoding gene (ppk) is found clustered together with two genes encoding putative exopolyphosphatases (ppx1 and ppx2) each having different domain compositions, with the gene order ppx1-ppk-ppx2. However, the specific function of these ppx genes remains unexplored. An in-frame deletion of ppx1 in Lacticaseibacillus paracasei BL23 resulted in bacteria unable to accumulate poly-P, whereas the disruption of ppx2 did not affect poly-P synthesis. The expression of ppk was not altered in the Δppx1 strain, and poly-P synthesis in this strain was only restored by expressing ppx1 in trans. Moreover, no poly-P synthesis was observed when ppk was expressed from a plasmid in the Δppx1 strain. Purified Ppx2 exhibited in vitro exopolyphosphatase activity, whereas no in vitro enzymatic activity could be demonstrated for Ppx1. This observation corresponds with the absence in Ppx1 of conserved motifs essential for catalysis found in characterized exopolyphosphatases. Furthermore, assays with purified Ppk and Ppx1 evidenced that Ppx1 enhanced Ppk activity. These results demonstrate that Ppx1 is essential for poly-P synthesis in Lc. paracasei and have unveiled, for the first time, an unexpected role of Ppx1 exopolyphosphatase in poly-P synthesis.IMPORTANCEPoly-P is a pivotal molecular player in bacteria, participating in a diverse array of processes ranging from stress resilience to pathogenesis while also serving as a functional component in probiotic bacteria. The synthesis of poly-P is tightly regulated, but the underlying mechanisms remain incompletely elucidated. Our study sheds light on the distinctive role played by the two exopolyphosphatases (Ppx) found in the Lactobacillaceae bacterial group, of relevance in food and health. This particular group is noteworthy for possessing two Ppx enzymes, supposedly involved in poly-P degradation. Remarkably, our investigation uncovers an unprecedented function of Ppx1 in Lacticaseibacillus paracasei, where its absence leads to the total cessation of poly-P synthesis, paralleling the impact observed upon eliminating the poly-P forming enzyme, poly-P kinase. Unlike the anticipated role as a conventional exopolyphosphatase, Ppx1 demonstrates an unexpected function. Our results added a layer of complexity to our understanding of poly-P dynamics in bacteria.

Phosphate Uptake and Its Relation to Arsenic Toxicity in Lactobacilli.

The use of probiotic lactobacilli has been proposed as a strategy to mitigate damage associated with exposure to toxic metals. Their protective effect against cationic metal ions, such as those of mercury or lead, is believed to stem from their chelating and accumulating potential. However, their retention of anionic toxic metalloids, such as inorganic arsenic, is generally low. Through the construction of mutants in phosphate transporter genes (pst) in Lactiplantibacillus plantarum and Lacticaseibacillus paracasei strains, coupled with arsenate [As(V)] uptake and toxicity assays, we determined that the incorporation of As(V), which structurally resembles phosphate, is likely facilitated by phosphate transporters. Surprisingly, inactivation in Lc. paracasei of PhoP, the transcriptional regulator of the two-component system PhoPR, a signal transducer involved in phosphate sensing, led to an increased resistance to arsenite [As(III)]. In comparison to the wild type, the phoP strain exhibited no differences in the ability to retain As(III), and there were no observed changes in the oxidation of As(III) to the less toxic As(V). These results reinforce the idea that specific transport, and not unspecific cell retention, plays a role in As(V) biosorption by lactobacilli, while they reveal an unexpected phenotype for the lack of the pleiotropic regulator PhoP.

ABC Transporter DerAB of Lactobacillus casei Mediates Resistance against Insect-Derived Defensins.

Bce-like systems mediate resistance against antimicrobial peptides in Firmicutes bacteria. Lactobacillus casei BL23 encodes an "orphan" ABC transporter that, based on homology to BceAB-like systems, was proposed to contribute to antimicrobial peptide resistance. A mutant lacking the permease subunit was tested for sensitivity against a collection of peptides derived from bacteria, fungi, insects, and humans. Our results show that the transporter specifically conferred resistance against insect-derived cysteine-stabilized αß defensins, and it was therefore renamed DerAB for defensin resistance ABC transporter. Surprisingly, cells lacking DerAB showed a marked increase in resistance against the lantibiotic nisin. This could be explained by significantly increased expression of the antimicrobial peptide resistance determinants regulated by the Bce-like systems PsdRSAB (formerly module 09) and ApsRSAB (formerly module 12). Bacterial two-hybrid studies in Escherichia coli showed that DerB could interact with proteins of the sensory complex in the Psd resistance system. We therefore propose that interaction of DerAB with this complex in the cell creates signaling interference and reduces the cell's potential to mount an effective nisin resistance response. In the absence of DerB, this negative interference is relieved, leading to the observed hyperactivation of the Psd module and thus increased resistance to nisin. Our results unravel the function of a previously uncharacterized Bce-like orphan resistance transporter with pleiotropic biological effects on the cell.IMPORTANCE Antimicrobial peptides (AMPs) play an important role in suppressing the growth of microorganisms. They can be produced by bacteria themselves-to inhibit competitors-but are also widely distributed in higher eukaryotes, including insects and mammals, where they form an important component of innate immunity. In low-GC-content Gram-positive bacteria, BceAB-like transporters play a crucial role in AMP resistance but have so far been primarily associated with interbacterial competition. Here, we show that the orphan transporter DerAB from the lactic acid bacterium Lactobacillus casei is crucial for high-level resistance against insect-derived AMPs. It therefore represents an important mechanism for interkingdom defense. Furthermore, our results support a signaling interference from DerAB on the PsdRSAB module that might prevent the activation of a full nisin response. The Bce modules from L. casei BL23 illustrate a biological paradox in which the intrinsic nisin detoxification potential only arises in the absence of a defensin-specific ABC transporter.

Ultrasonically-Assisted and Conventional Extraction from Erodium Glaucophyllum Roots Using Ethanol:Water Mixtures: Phenolic Characterization, Antioxidant, and Anti-Inflammatory Activities.

The paper presents experimental results concerning the ultrasonically-assisted extraction of bioactive compounds from Erodium glaucophyllum roots. A comparison with conventional methodology is presented, and thereby the phytochemical composition and the antioxidant and anti-inflammatory activities of extracts are evaluated. The phenolic profile of Erodium extracts was analyzed by TOF-LC-MS-MS. The identification of phenolic compounds revealed that the major component was (+)-gallocatechin in the aqueous extracts obtained for the different extraction methodologies. The highest quantity of phenolic compounds and antioxidant capacity was found in the hydroethanolic extract obtained by conventional extraction (29.22-25.50 mg GAE/g DM; 21.174 mM Trolox equivalent). The highest content of carotenoids, varying from 0.035 to 0.114 mg/g dry matter, was reached by ultrasonic-assisted extraction. Furthermore, Erodium extracts showed a potent inhibition of the inflammatory reaction by means of the inhibition of tumor necrosis factor-alpha (TNF-α). The extracts obtained when ultrasound extraction was combined with ethanol:water (50:50, v/v) presented the greatest inhibition (92%).

Effects of Ultrasound-Assisted Extraction and Solvent on the Phenolic Profile, Bacterial Growth, and Anti-Inflammatory/Antioxidant Activities of Mediterranean Olive and Fig Leaves Extracts.

Mediterranean plants, such as fig and olive leaves, are well-known to exert beneficial effects in humans because of the presence of a wide range of bioactive compounds. However, scarce information regarding the impact of extraction methods, such as ultrasound and types of solvents, on their profile of antioxidant and anti-inflammatory compounds is provided. In addition, no information is available on the effects of extraction methods and solvents on the inhibition of pathogenic bacteria or promoting probiotic growth. In this scenario, this study was aimed to study the effects of ultrasound-assisted extraction (UAE) and solvent on the phenolic profile (Triple TOF-LC-MS/MS), antioxidant and anti-inflammatory compounds of olive and fig leaves. Results showed that UAE extracted more carotenoids compared to conventional extraction, while the conventional extraction impacted on higher flavonoids (olive leaves) and total phenolics (fig leaves). The antioxidant capacity of aqueous extract of fig leaves was three times higher than the extract obtained with ethanol for conventional extraction and four times higher for UAE. In general terms, hydroethanolic extracts presented the highest bacterial growth inhibition, and showed the highest anti-inflammatory activity. In conclusion, these side streams can be used as sources of bioactive compounds for further development of high-added-value products.

MAMI: a birth cohort focused on maternal-infant microbiota during early life.

BACKGROUND: Early microbial colonization is a relevant aspect in human health. Altered microbial colonization patterns have been linked to an increased risk of non-communicable diseases (NCDs). Advances in understanding host-microbe interactions highlight the pivotal role of maternal microbiota on infant health programming. This birth cohort is aimed to characterize the maternal microbes transferred to neonates during the first 1000 days of life, as well as to identify the potential host and environmental factors, such as gestational age, mode of delivery, maternal/infant diet, and exposure to antibiotics, which affect early microbial colonization. METHODS: MAMI is a prospective mother-infant birth cohort in the Spanish-Mediterranean area. Mothers were enrolled at the end of pregnancy and families were follow-up during the first years of life. Maternal-infant biological samples were collected at several time points from birth to 24 months of life. Clinical and anthropometric characteristics and dietary information is available. Specific qPCR and 16S rRNA gene sequencing as well as short chain fatty acid (SCFAs) profile would be obtained. Multivariable models will be used to identy associations between microbiota and clinical and anthropometric data controlling for confounders. MAMI would contribute to a better understanding of the interaction between diet, microbiota and host response in early life health programming, enabling new applications in the field of personalized nutrition and medicine. TRIAL REGISTRATION: The study is registered on the ClinicalTrial.gov platform NCT03552939. (June 12, 2018).

Peptide and amino acid metabolism is controlled by an OmpR-family response regulator in Lactobacillus casei.

A Lactobacillus casei BL23 strain defective in an OmpR-family response regulator encoded by LCABL_18980 (PrcR, RR11), showed enhanced proteolytic activity caused by overexpression of the gene encoding the proteinase PrtP. Transcriptomic analysis revealed that, in addition to prtP expression, PrcR regulates genes encoding peptide and amino acid transporters, intracellular peptidases and amino acid biosynthetic pathways, among others. Binding of PrcR to twelve promoter regions of both upregulated and downregulated genes, including its own promoter, was demonstrated by electrophoretic mobility shift assays showing that PrcR can act as a transcriptional repressor or activator. Phosphorylation of PrcR increased its DNA binding activity and this effect was abolished after replacement of the phosphorylatable residue Asp-52 by alanine. Comparison of the transcript levels in cells grown in the presence or absence of tryptone in the growth medium revealed that PrcR activity responded to the presence of a complex amino acid source in the growth medium. We conclude that the PrcR plays a major role in the control of the peptide and amino acid metabolism in L. casei BL23. Orthologous prcR genes are present in most members of the Lactobacillaceae and Leuconostocaceae families. We hypothesize that they play a similar role in these bacterial groups.

Characterization of the binding capacity of mercurial species in Lactobacillus strains.

BACKGROUND: Metal sequestration by bacteria has been proposed as a strategy to counteract metal contamination in foodstuffs. Lactobacilli can interact with metals, although studies with important foodborne metals such as inorganic [Hg(II)] or organic (CH3 Hg) mercury are lacking. Lactobacilli were evaluated for their potential to bind these contaminants and the nature of the interaction was assessed by the use of metal competitors, chemical and enzymatical treatments, and mutants affected in the cell wall structure. RESULTS: Lactobacillus strains efficiently bound Hg(II) and CH3 Hg. Mercury binding by Lactobacillus casei BL23 was independent of cell viability. In BL23, both forms of mercury were cell wall bound. Their interaction was not inhibited by cations and it was resistant to chelating agents and protein digestion. Lactobacillus casei mutants affected in genes involved in the modulation of the negative charge of the cell wall anionic polymer lipoteichoic acid showed increased mercury biosorption. In these mutants, mercury toxicity was enhanced compared to wild-type bacteria. These data suggest that lipoteichoic acid itself or the physicochemical characteristics that it confers to the cell wall play a major role in mercury complexation. CONCLUSION: This is the first example of the biosorption of Hg(II) and CH3 Hg in lactobacilli and it represents a first step towards their possible use as agents for diminishing mercury bioaccessibility from food at the gastrointestinal tract. © 2017 Society of Chemical Industry.

Coupling of postural activity with motion of a ship at sea.

On land, body sway during stance becomes coupled with imposed oscillations of the illuminated environment or of the support surface. This coupling appears to have the function of stabilizing the body relative to the illuminated or inertial environment. In previous research, the stimulus has been limited to motion in a single axis. Little is known about our ability to couple postural activity with complex, multi-axis oscillations. On a ship at sea, we evaluated postural activity using measures of body movement, as such, and we separately evaluated a direct measure of coupling between body movement and ship motion. Participants were tested while facing fore-aft and athwartship. We compared postural activity between participants who had been seasick at the beginning of the voyage and those who had not. Coupling of postural activity with ship motion differed between body axes as a function of body orientation relative to the ship. In addition, coupling differed between participants who had been seasick at the beginning of the voyage and those who had not. We discuss the results in terms of implications for general theories of postural control, and for prediction of susceptibility to seasickness in individuals.

Accumulation of polyphosphate in Lactobacillus spp. and its involvement in stress resistance.

Polyphosphate (poly-P) is a polymer of phosphate residues synthesized and in some cases accumulated by microorganisms, where it plays crucial physiological roles such as the participation in the response to nutritional stringencies and environmental stresses. Poly-P metabolism has received little attention in Lactobacillus, a genus of lactic acid bacteria of relevance for food production and health of humans and animals. We show that among 34 strains of Lactobacillus, 18 of them accumulated intracellular poly-P granules, as revealed by specific staining and electron microscopy. Poly-P accumulation was generally dependent on the presence of elevated phosphate concentrations in the culture medium, and it correlated with the presence of polyphosphate kinase (ppk) genes in the genomes. The ppk gene from Lactobacillus displayed a genetic arrangement in which it was flanked by two genes encoding exopolyphosphatases of the Ppx-GppA family. The ppk functionality was corroborated by its disruption (LCABL_27820 gene) in Lactobacillus casei BL23 strain. The constructed ppk mutant showed a lack of intracellular poly-P granules and a drastic reduction in poly-P synthesis. Resistance to several stresses was tested in the ppk-disrupted strain, showing that it presented a diminished growth under high-salt or low-pH conditions and an increased sensitivity to oxidative stress. These results show that poly-P accumulation is a characteristic of some strains of lactobacilli and may thus play important roles in the physiology of these microorganisms.

The impact of burial depth on Centaurea diluta emergence and modelling of its growth using a nonlinear regression and artificial neural network.

BACKGROUND: Centaurea diluta Aiton (North African knapweed) is a major weed concern in Spain as a result of the limited herbicides capable of controlling it, and the limited knowledge of its biology hinders the development of integrated weed management strategies. RESULTS: The current study presents results from two experiments that aimed to: (i) determine the effect of seed burial on seedling emergence; and (ii) model its phenology progression using sigmoidal (SRM) and artificial neural network models (ANN) based on different cohort emergence times. In the first experiment, burial at 2 cm and 5 cm decreased C. diluta emergence by 54% and 90%, respectively, compared to the emergence at 0 cm. In the second experiment, without crop-weed competition conditions, the emergence delay led to reductions in leaf number, rosette diameter, plant height and dry biomass by 63%, 50%, 59% and 93%, respectively. Seed production per plant exceeded 21 469. According to the growth model, leaf number was the most consistent morphological trait and critical for timing weed control actions, so it was used to compare SRMs and ANNs. On average, ANNs increased the precision in 5.72% (± 2.4 leaves) compared to SRMs. This slight performance of ANNs may be valuable for controlling C. diluta because control methods must be applied at the 4-leaf stage to achieve good efficacy. CONCLUSION: Seed burial at 5 cm depth is an effective method reducing C. diluta emergence. ANNs accurately predicted the leaf number employing environmental variables can help increase the efficiency of C. diluta control actions and reduce the risk of escapes. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Cross-regulation of Aps-promoters in Lacticaseibacillus paracasei by the PsdR response regulator in response to lantibiotics.

The PsdRSAB and ApsRSAB detoxification modules, together with the antimicrobial peptides (AMPs)-resistance determinants Dlt system and MprF protein, play major roles in the response to AMPs in Lacticaseibacillus paracasei BL23. Sensitivity assays with a collection of mutants showed that the PsdAB ABC transporter and the Dlt system are the main subtilin resistance determinants. Quantification of the transcriptional response to subtilin indicate that this response is exclusively regulated by the two paralogous systems PsdRSAB and ApsRSAB. Remarkably, a cross-regulation of the derAB, mprF and dlt-operon genes-usually under control of ApsR-by PsdR in response to subtilin was unveiled. The high similarity of the predicted structures of both response regulators (RR), and of the RR-binding sites support this possibility, which we experimentally verified by protein-DNA binding studies. ApsR-P shows a preferential binding in the order PderA > Pdlt > PmprF > PpsdA. However, PsdR-P bound with similar apparent affinity constants to the four promoters. This supports the cross-regulation of derAB, mprF and the dlt-operon by PsdR. The possibility of cross-regulation at the level of RR-promoter interaction allows some regulatory overlap with two RRs controlling the expression of systems involved in maintenance of critical cell membrane functions in response to lantibiotics.

Characterization of a regulatory network of peptide antibiotic detoxification modules in Lactobacillus casei BL23.

Two-component systems (TCS) are major signal transduction pathways that allow bacteria to detect and respond to environmental and intracellular changes. A group of TCS has been shown to be involved in the response against antimicrobial peptides (AMPs). These TCS are characterized by the possession of intramembrane-sensing histidine kinases, and they are usually associated with ABC transporters of the peptide-7 exporter family (Pep7E). Lactobacillus casei BL23 encodes two TCS belonging to this group (TCS09 and TCS12) that are located next to two ABC transporters (ABC09 and ABC12), as well as a third Pep7E ABC transporter not genetically associated with any TCS (orphan ABC). This study addressed the involvement of modules TCS09/ABC09 and TCS12/ABC12 in AMP resistance. Results showed that both systems contribute to L. casei resistance to AMPs, and that each TCS constitutes a functional unit with its corresponding ABC transporter. Analysis of transcriptional levels showed that module 09 is required for the induction of ABC09 expression in response to nisin. In contrast, module 12 controls a wider regulon that encompasses the orphan ABC, the dlt operon (d-alanylation of teichoid acids), and the mprF gene (l-lysinylation of phospholipids), thereby controlling properties of the cell envelope. Furthermore, the characterization of a dltA mutant showed that Dlt plays a major role in AMP resistance in L. casei. This is the first report on the regulation of the response of L. casei to AMPs, giving insight into its ability to adapt to the challenging environments that it encounters as a probiotic microorganism.

Study of the biosynthesis and functionality of polyphosphate in Bifidobacterium longum KABP042.

Polyphosphate (poly-P) biosynthesis in bacteria has been linked to many physiological processes and has been characterized as an interesting functional molecule involved in intestinal homeostasis. We determined the capacity for poly-P production of 18 probiotic strains mainly belonging to Bifidobacterium and former Lactobacillus genera, showing that poly-P synthesis varied widely between strains and is dependent on the availability of phosphate and the growth phase. Bifidobacteria were especially capable of poly-P synthesis and poly-P kinase (ppk) genes were identified in their genomes together with a repertoire of genes involved in phosphate transport and metabolism. In Bifidobacterium longum KABP042, the strain we found with highest poly-P production, variations in ppk expression were linked to growth conditions and presence of phosphate in the medium. Moreover, the strain produced poly-P in presence of breast milk and lacto-N-tetraose increased the amount of poly-P synthesized. Compared to KABP042 supernatants low in poly-P, exposure of Caco-2 cells to KABP042 supernatants rich in poly-P resulted in decreased epithelial permeability and increased barrier resistance, induction of epithelial protecting factors such as HSP27 and enhanced expression of tight junction protein genes. These results highlight the role of bifidobacteria-derived poly-P as a strain-dependent functional factor acting on epithelial integrity.

Proteomic and transcriptomic analysis of the response to bile stress of Lactobacillus casei BL23.

Lactobacillus casei is a lactic acid bacterium commonly found in the gastrointestinal tract of animals, and some strains are used as probiotics. The ability of probiotic strains to survive the passage through the gastrointestinal tract is considered a key factor for their probiotic action. Therefore, tolerance to bile salts is a desirable feature for probiotic strains. In this study we have characterized the response of L. casei BL23 to bile by a transcriptomic and proteomic approach. The analysis revealed that exposure to bile induced changes in the abundance of 52 proteins and the transcript levels of 67 genes. The observed changes affected genes and proteins involved in the stress response, fatty acid and cell wall biosynthesis, metabolism of carbohydrates, transport of peptides, coenzyme levels, membrane H(+)-ATPase, and a number of uncharacterized genes and proteins. These data provide new insights into the mechanisms that enable L. casei BL23 to cope with bile stress.

Influence of two-component signal transduction systems of Lactobacillus casei BL23 on tolerance to stress conditions.

Lactobacillus casei BL23 carries 17 two-component signal transduction systems. Insertional mutations were introduced into each gene encoding the cognate response regulators, and their effects on growth under different conditions were assayed. Inactivation of systems TC01, TC06, and TC12 (LCABL_02080-LCABL_02090, LCABL_12050-LCABL_12060, and LCABL_19600-LCABL_19610, respectively) led to major growth defects under the conditions assayed.

The relationship between alexithymia and psychological factors in systemic lupus erythematosus.

BACKGROUND: Alexithymia has been described as an important dimension in several medical diseases. Systemic lupus erythematosus (SLE) is a chronic condition characterized by unpredictable clinical manifestations. Our aim is to reveal which factors (psychological factors and quality of life dimensions) are associated with alexithymia in SLE patients. METHODS: Fifty-three sequential SLE patients (ACR criteria) and 41 asthma patients were studied by means of validated scales for alexithymia (Toronto Alexithymia Scale), psychopathology (Brief Symptom Inventory, Hospital Anxiety and Depression Scale), personality dimensions (NEO-FFI), and quality of life (Short Form-36 Health Survey). Systemic lupus erythematosus patient's clinical and laboratorial evaluation was performed by indicators of activity (Systemic Lupus Erythematosus Disease Activity Index) of accumulated damage (Systemic Lupus International Collaborating Clinics/ACR Damage Index), length of disease, and therapy. RESULTS: An association between alexithymia and psychopathological symptoms, and personality and quality of life dimensions was found. By means of multiple regression analysis, openness and depression were the 2 predictors for alexithymia in SLE patients. We found a high prevalence rate of alexithymia in SLE patients; however, when controlling for depression symptoms (Hospital Anxiety and Depression Scale-Depression, <7), we found a lower percentage of alexithymic traits than that of the total sample of SLE. CONCLUSION: Alexithymia was associated with psychological distress and with quality of life impairment. Understanding the role of psychological factors in SLE patients may contribute to a more comprehensive perspective of the disease, its impact on patient's daily routine, and how patients adapt emotionally to a chronic disease.

Effect of Aging, Gender and Sensory Stimulation of TRPV1 Receptors with Capsaicin on Spontaneous Swallowing Frequency in Patients with Oropharyngeal Dysphagia: A Proof-of-Concept Study.

Spontaneous swallowing contributes to airway protection and depends on the activation of brainstem reflex circuits in the central pattern generator (CPG). We studied the effect of age and gender on spontaneous swallowing frequency (SSF) in healthy volunteers and assessed basal SSF and TRPV1 stimulation effect on SSF in patients with post-stroke oropharyngeal dysphagia (OD). The effect of age and gender on SSF was examined on 141 healthy adult volunteers (HV) divided into three groups: GI-18-39 yr, GII-40-59 yr, and GIII->60 yr. OD was assessed by the Volume-Viscosity Swallowing Test (VVST). The effect of sensory stimulation with capsaicin 10-5 M (TRPV1 agonist) was evaluated in 17 patients with post-stroke OD, using the SSF. SSF was recorded in all participants during 10 min using surface electromyography (sEMG) of the suprahyoid muscles and an omnidirectional accelerometer placed over the cricothyroid cartilage. SSF was significantly reduced in GII (0.73 ± 0.50 swallows/min; p = 0.0385) and GIII (0.50 ± 0.31 swallows/min; p < 0.0001) compared to GI (1.03 ± 0.62 swallows/min), and there was a moderate significant correlation between age and SFF (r = -0.3810; p < 0.0001). No effect of gender on SSF was observed. Capsaicin caused a strong and significant increase in SSF after the TRPV1 stimulation when comparing to basal condition (pre-capsaicin: 0.41 ± 0.32 swallows/min vs post-capsaicin: 0.81 ± 0.51 swallow/min; p = 0.0003). OD in patients with post-stroke OD and acute stimulation with TRPV1 agonists caused a significant increase in SSF, further suggesting the potential role of pharmacological stimulation of sensory pathways as a therapeutic strategy for CPG activation in patients with OD.

Bacterial growth and biological properties of Cymbopogon schoenanthus and Ziziphus lotus are modulated by extraction conditions.

The present study aims to evaluate the antibacterial activity and biological properties of two traditional Saharian plants (Cymbopogon schoenanthus and Ziziphus lotus). The plant extracts were obtained by using a different combination of extraction methods (conventional vs. ultrasound-assisted) and solvents (water vs. ethanol:water (50:50, v/v)). The antioxidant profile, anti-inflammatory activity and impact on bacterial growth (foodborne and probiotic bacteria) of the obtained extracts were assessed. The plant species showed the hierarchically more important role in determining the biological properties of the extracts, followed by extraction solvent and extraction conditions. Conventional Z. lotus hydroethanolic extracts showed the highest total phenolic content (20.4 mg GAE/g), while Z. lotus ethanol extracts from ultrasound-assisted process presented the highest content of carotenoids (0.15 mg/g). In addition, ultrasound-assisted Z. lotus hydroethanolic extracts presented the highest in vitro radical scavenging activity, being 7.93 mmol Trolox/g. Multivariate analysis statistics (PCA) showed that both the extraction methodology and the solvent used strongly affected the bacterial growth. Z. lotus mainly decreased the growth rate of S. aureus and L. innocua. Interestingly, the aqueous extracts of this plant as well as those from C. schoenanthus, obtained by conventional extraction, significantly increased the growth rate and the maximal optical density of L. casei. Aqueous extracts of both Z. lotus and C. schoenanthus slightly influenced the growth of Bifidobacterium. Overall, the extracts of these plants showed selective activities with respect to pathogens and probiotic bacteria and may provide an advantage both in terms of antimicrobial and prebiotic activity.

Human milk and mucosa-associated disaccharides impact on cultured infant fecal microbiota.

Human milk oligosaccharides (HMOs) are a mixture of structurally diverse carbohydrates that contribute to shape a healthy gut microbiota composition. The great diversity of the HMOs structures does not allow the attribution of specific prebiotic characteristics to single milk oligosaccharides. We analyze here the utilization of four disaccharides, lacto-N-biose (LNB), galacto-N-biose (GNB), fucosyl-α1,3-GlcNAc (3FN) and fucosyl-α1,6-GlcNAc (6FN), that form part of HMOs and glycoprotein structures, by the infant fecal microbiota. LNB significantly increased the total levels of bifidobacteria and the species Bifidobacterium breve and Bifidobacterium bifidum. The Lactobacillus genus levels were increased by 3FN fermentation and B. breve by GNB and 3FN. There was a significant reduction of Blautia coccoides group with LNB and 3FN. In addition, 6FN significantly reduced the levels of Enterobacteriaceae family members. Significantly higher concentrations of lactate, formate and acetate were produced in cultures containing either LNB or GNB in comparison with control cultures. Additionally, after fermentation of the oligosaccharides by the fecal microbiota, several Bifidobacterium strains were isolated and identified. The results presented here indicated that each, LNB, GNB and 3FN disaccharide, might have a specific beneficial effect in the infant gut microbiota and they are potential prebiotics for application in infant foods.