Evidence of the Dysbiotic Effect of Psychotropics on Gut Microbiota and Capacity of Probiotics to Alleviate Related Dysbiosis in a Model of the Human Colon.

Growing evidence indicates that non-antibiotic therapeutics significantly impact human health by modulating gut microbiome composition and metabolism. In this study, we investigated the impact of two psychotropic drugs, aripiprazole and (S)-citalopram, on gut microbiome composition and its metabolic activity, as well as the potential of probiotics to attenuate related dysbiosis using an ex vivo model of the human colon. After 48 h of fermentation, the two psychotropics demonstrated distinct modulatory effects on the gut microbiome. Aripiprazole, at the phylum level, significantly decreased the relative abundances of Firmicutes and Actinobacteria, while increasing the proportion of Proteobacteria. Moreover, the families Lachnospiraceae, Lactobacillaceae, and Erysipelotrichaceae were also reduced by aripiprazole treatment compared to the control group. In addition, aripiprazole lowered the levels of butyrate, propionate, and acetate, as measured by gas chromatography (GC). On the other hand, (S)-citalopram increased the alpha diversity of microbial taxa, with no differences observed between groups at the family and genus level. Furthermore, a probiotic combination of Lacticaseibacillus rhamnosus HA-114 and Bifidobacterium longum R0175 alleviated gut microbiome alterations and increased the production of short-chain fatty acids to a similar level as the control. These findings provide compelling evidence that psychotropics modulate the composition and function of the gut microbiome, while the probiotic can mitigate related dysbiosis.

Bioengineered Wheat Arabinoxylan - Fostering Next-Generation Prebiotics Targeting Health-Related Gut Microbes.

Dietary prebiotic fibers play an important role in modulating gut microbiota by enhancing the abundance of beneficial microorganisms and their bioactive metabolites. However, dietary fibers are a structurally heterogeneous class of polysaccharides, varying in molar mass, branching patterns, and monosaccharide composition, which could influence their utilization by various gut microorganisms. The present study aimed to investigate the effects of molar mass and chemical structure of wheat arabinoxylan fiber (AX) on the growth and metabolism of two key gut resident bacteria (Faecalibacterium prausnitzii and Lacticaseibacillus rhamnosus LGG), which are linked to human health. For this purpose, low, medium, and high molar masses of AX (LAX, MAX, and HAX, respectively) were modified with specific α-arabinofuranosidases to leave only singly substituted, only doubly substituted, or unsubstituted xylose units. Almost all the modified AX samples showed a better prebiotic score than unmodified AX for different molar masses. The modified LAX exhibited a better prebiotic effect than HAX and MAX. In addition, LAX, with doubly substituted xylose units, exhibited the highest prebiotic potential and SCFA production by both microorganisms. Furthermore, AX, either singly or doubly substituted, had a consistent impact on L. rhamnosus growth, whereas AX, with all arabinose residues removed, had a greater impact on F. prausnitzii. These findings support the potential of bioengineered AX as next-generation prebiotics targeting health-related gut microbes.

Bacteriocinogenic probiotics as an integrated alternative to antibiotics in chicken production - why and how?

The misuse of antibiotics in the livestock industry has played an important role in the spread of resistant superbugs with severe health implications for humans. With the recent ban on the use of antibiotics in poultry and poultry feed in Canada and the USA, poultry farmers will have to rely on the use of alternatives to antibiotics (such as feed acidifiers, antibodies, bacteriophages, antimicrobial peptides, prebiotics, and probiotics) to maintain the same productivity and health of their livestock. Of particular interest are bacteriocinogenic probiotics, that is, bacterial strains capable of producing bacteriocins that confer health benefits on the host. These bacterial strains have multiple promising features, such as the ability to attach to the host mucosa, colonize, proliferate, and produce advantageous products such as bacteriocins and short-chain fatty acids. These not only affect pathogenic colonization but improve poultry phenotype as well. Bacteriocins are antimicrobial peptides with multiple promising features such as being non-harmful for human and animal consumption, non-disruptive to the host microbiota eubiosis, non-cytotoxic, and non-carcinogenic. Therefore, bacteriocinogenic probiotics are at the forefront to be excellent candidates for effective replacements to antibiotics. While evidence of their safety and effectiveness is accumulating in vitro and in vivo in inhibiting pathogens while promoting animal health, their safety and history of use in livestock remains unclear and requires additional investigations. In the present paper, we review the safety assessment regulations and commercialization policies on existing and novel bacteriocinogenic and bacteriocin products intended to be used in poultry feed as an alternative to antibiotics.

Screening, characterization and growth of γ-aminobutyric acid-producing probiotic candidates from food origin under simulated colonic conditions.

AIMS: This study aims to isolate probiotic bacteria candidates from various starter cultures and fermented foods and characterize their ability to produce γ-aminobutyric acid (GABA). GABA is a major inhibitory neuromediator of the central and enteric nervous systems with a role in several health disorders. METHODS AND RESULTS: Fourteen strains of lactic acid bacteria were isolated from food environment and screened for the presence of the glutamate decarboxylase (gadB) gene using PCR and GAD enzymatic assay. The identified potent GABA-producers included Strep. thermophilus, Lactiplantibacillus plantarum and Lact. delbrueckii subsp. bulgaricus. GC-FID analyses confirmed the high GABA production capacity of Strep. thermophilus ST16 (1641.5 ± 154.15 µmol l-1 ), Strep. thermophilus ST8 (1724.5 ± 48.08 µmol/L). To a lesser extent, Bif. animalis ST20, Lact. acidophilus LP16-2 and Ent. faecium ST3 produced 947.5 ± 70.71, 918.0 ± 121.42, and 907.83 ± 55.15 µmol/L of GABA, respectively. These potent strains were able to grow and produce GABA in MRS broth and pre-fermented Macfarlane broth, the latter medium mimicking the nutrient and metabolome composition encountered in the colon. The identified bioactive strains exhibited strong biological safety and probiotic potential profiles as indicated by sensitivity to antibiotics, absence of virulence factors and survival in gastrointestinal conditions. CONCLUSIONS: Several GABA producing probiotic candidates, including Bif. animals ST20, Strep. thermophilus ST8, Lact. acidophilus LP16-2, L. plantarum LP6 & LP9, and Ent. faecium ST3, have shown potential to grow under simulated colonic conditions. SIGNIFICANCE AND IMPACT OF STUDY: Findings from this study provide evidence of the suitability of the isolated GABA-producing probiotic candidates for the development of health-oriented functional food products.

Gut Microbiota Extracellular Vesicles as Signaling Molecules Mediating Host-Microbiota Communications.

Over the past decade, gut microbiota dysbiosis has been linked to many health disorders; however, the detailed mechanism of this correlation remains unclear. Gut microbiota can communicate with the host through immunological or metabolic signalling. Recently, microbiota-released extracellular vesicles (MEVs) have emerged as significant mediators in the intercellular signalling mechanism that could be an integral part of microbiota-host communications. MEVs are small membrane-bound vesicles that encase a broad spectrum of biologically active compounds (i.e., proteins, mRNA, miRNA, DNA, carbohydrates, and lipids), thus mediating the horizontal transfer of their cargo across intra- and intercellular space. In this study, we provide a comprehensive and in-depth discussion of the biogenesis of microbial-derived EVs, their classification and routes of production, as well as their role in inter-bacterial and inter-kingdom signaling.

Bacteriocinogenic properties of Escherichia coli P2C isolated from pig gastrointestinal tract: purification and characterization of microcin V.

The aim of this study was to isolate and investigate the bacteriocinogenic and probiotic potential of new Gram-negative isolates. Of 22 bacterial isolates from pig intestine and chicken crops, ten isolates had demonstrated a good activity, and the most potent five strains were identified as four E. coli and one as Proteus sp. No virulence factors were detected for E. coli strains isolated from pig intestine. The semi-purified microcins proved to be resistant to temperature and pH variation, but sensitive to proteolytic enzymes. Of particular interest, strain E. coli P2C was the most potent, free of virulence genes and sensitive to tested antibiotics. Purification procedure revealed the presence of a single pure peak having a molecular mass of 8733.94 Da and matching microcin V (MccV). The sequence obtained by LC-MS/MS confirmed the presence of MccV. Purified MccV showed a good activity against pathogenic coliforms, especially E. coli O1K1H7 involved in avian colibacillosis. The present study provides evidence that E. coli strains isolated from pig intestine produce microcin-like substances. E. coli P2C is a safe MccV producer that could be a good candidate for its application as novel probiotic strain to protect livestock and enhance growth performance.

Influence of electro-activated solutions of weak organic acid salts on microbial quality and overall appearance of blueberries during storage.

The aim of this work was to study the potential of diluted electro-activated solutions of weak organic acid salts (potassium acetate, potassium citrate and calcium lactate) to extend the shelf life of blueberries during post-harvest storage. The sanitizing capacity of these solutions was studied against pathogenic bacteria Listeria monocytogenes and E. coli O157:H7 as well as phytopathogenic fungi A. alternata, F. oxysporum and B. cinerea. The results showed that a 5-min treatment of inoculated blueberries with electro-activated solutions resulted in a 4 log CFU/g reduction in Listeria monocytogenes for all solutions. For E. coli O157:H7, the electro-activated potassium acetate and potassium citrate solutions achieved a decrease of 3.5 log CFU/g after 5 min of berry washing. The most important fungus reduction was found when blueberries were washed with an electro-activated solution of potassium acetate and a NaOCl solution. After 5 min of blueberry washing with an electro-activated potassium acetate solution, a very high reduction effect was observed for A. alternata, F. oxysporum and B. cinerea, which showed survival levels of only 2.2 ± 0.16, 0.34 ± 0.15 and 0.21 ± 0.16 log CFU/g, respectively. Regarding the effect of the washing on the organoleptic quality of blueberries, the obtained results showed no negative effect on the product color or textural profile. Finally, this work suggests that washing with electro-activated solutions of weak organic acid salts can be used to enhance the shelf-life of blueberries during post-harvest storage.

Collagencin, an antibacterial peptide from fish collagen: Activity, structure and interaction dynamics with membrane.

In this study, we first report characterization of collagencin, an antimicrobial peptide identified from fish collagen hydrolysate. The peptide completely inhibited the growth of Staphylococcus aureus at 1.88 mM. Although non-toxic up to 470 µM, collagencin was hemolytic at higher concentrations. The secondary structure of collagencin was mainly composed by ß-sheet and ß-turn as determined by CD measurements and molecular dynamics. The peptide is likely to form ß-sheet structure under hydrophobic environments and interacts with both anionic (phosphatidylglycerol) and zwitterionic (phosphoethanolamine and phosphatidylcholine) lipids as shown with CD spectroscopy and molecular dynamics. The peptide formed several hydrogen bonds with both POPG and POPE lipids and remained at membrane-water interface, suggesting that collagencin antibacterial action follows a carpet mechanism. Collagenous fish wastes could be processed by enzymatic hydrolysis and transformed into products of high value having functional or biological properties. Marine collagens are a promising source of antimicrobial peptides with new implications in food safety and human health.

Purification and characterization of four antibacterial peptides from protamex hydrolysate of Atlantic mackerel (Scomber scombrus) by-products.

Proteins from fish by-product sources are valuable source of bioactive peptides and show promise as functional foods ingredients. The objective of the present study was to isolate and characterize antibacterial peptides from protamex hydrolysates of Atlantic mackerel (Scomber scombrus) by-products. Four sequences SIFIQRFTT (P4), RKSGDPLGR (P8.1), AKPGDGAGSGPR (P8.2) and GLPGPLGPAGPK (P11) were identified in peptide fractions separated using RP-HPLC. At 200 µg mL(-1), while peptides P8.1, P8.2 and P11 exhibited partial inhibition, P4 totally inhibited tested Gram-positive (Listeria innocua) and Gram-negative (Escherichia coli) bacterial strains. These results suggest that the protein hydrolysate derived from mackerel by-products could be used as an antimicrobial ingredient in both functional food and nutraceutical applications.

Stability of Secondary and Tertiary Structures of Virus-Like Particles Representing Noroviruses: Effects of pH, Ionic Strength, and Temperature and Implications for Adhesion to Surfaces.

Loss of ordered molecular structure in proteins is known to increase their adhesion to surfaces. The aim of this work was to study the stability of norovirus secondary and tertiary structures and its implications for viral adhesion to fresh foods and agrifood surfaces. The pH, ionic strength, and temperature conditions studied correspond to those prevalent in the principal vehicles of viral transmission (vomit and feces) and in the food processing and handling environment (pasteurization and refrigeration). The structures of virus-like particles representing GI.1, GII.4, and feline calicivirus (FCV) were studied using circular dichroism and intrinsic UV fluorescence. The particles were remarkably stable under most of the conditions. However, heating to 65°C caused losses of ß-strand structure, notably in GI.1 and FCV, while at 75°C the α-helix content of GII.4 and FCV decreased and tertiary structures unfolded in all three cases. Combining temperature with pH or ionic strength caused variable losses of structure depending on the particle type. Regardless of pH, heating to pasteurization temperatures or higher would be required to increase GII.4 and FCV adhesion, while either low or high temperatures would favor GI.1 adhesion. Regardless of temperature, increased ionic strength would increase GII.4 adhesion but would decrease GI.1 adhesion. FCV adsorption would be greater at refrigeration, pasteurization, or high temperature combined with a low salt concentration or at a higher NaCl concentration regardless of temperature. Norovirus adhesion mediated by hydrophobic interaction may depend on hydrophobic residues normally exposed on the capsid surface at pH 3, pH 8, physiological ionic strength, and low temperature, while at pasteurization temperatures it may rely more on buried hydrophobic residues exposed upon structural rearrangement.

Lasso-inspired peptides with distinct antibacterial mechanisms.

Microcin J25 (MccJ25) is an antibacterial peptide with a peculiar molecular structure consisting of 21 amino acids and a unique lasso topology that makes it highly stable. We synthesized various MccJ25-derived peptides that retained some of the inhibitory activity of the native molecule against Salmonella enterica and Escherichia coli. Of the tested peptides, C1, 7-21C and WK_7-21 were the most inhibitory peptides (MIC = 1-250 µM), but all three were less potent than MccJ25. While MccJ25 was not active against Gram-positive bacteria, the three derived peptides were slightly inhibitory to Gram-positive bacteria (MIC ≥ 250 µM). At 5 µM, C1, 7-21C and WK_7-21 reduced E. coli RNA polymerase activity by respectively, 23.4, 37.4 and 65.0 %. The MccJ25 and its derived peptides all appeared to affect the respiratory apparatus of S. enterica. Based on circular dichroism and FTIR spectroscopy, the peptides also interact with bacterial membrane phospholipids. These results suggest the possibility of producing potent MccJ25-derived peptides lacking the lasso structure.

Symbiotic maple saps minimize disruption of the mice intestinal microbiota after oral antibiotic administration.

This study was undertaken to evaluate the in vivo impact of new symbiotic products based on liquid maple sap or its concentrate. Sap and concentrate, with or without inulin (2%), were inoculated with Bifidobacterium lactis Bb12 and Lactobacillus rhamnosus GG valio at initial counts of 2-4 × 10(8) cfu mL(-1). The experiments started with intra-gastric administration of antibiotic (kanamycin 40 mg in 0.1 cc) (to induce microbiota disturbance and/or diarrhea) to 3-to-5-week-old C57BL/6 female mice followed by a combination of prebiotic and probiotics included in the maple sap or its concentrate for a week. The combination inulin and probiotics in maple sap and concentrate appeared to minimize the antibiotic-induced breakdown of mice microbiota with a marked effect on bifidobacterium and bacteroides levels, thus permitting a more rapid re-establishment of the baseline microbiota levels. Results suggest that maple sap and its concentrate represent good candidates for the production of non-dairy functional foods.

Bacteriocinogenic properties and in vitro probiotic potential of enterococci from Tunisian dairy products.

The aim of this study was to isolate new bacteriocinogenic strains with putative probiotic potential from various Tunisian fermented milks. A total of 44 Gram-positive catalase-negative isolates were colony-purified and screened for antimicrobial activity. Of inhibitory isolates, four were identified as Enterococcus durans and one as Enterococcus faecalis using 16S rRNA gene sequence. The five strains were sensitive to penicillin G, all aminoglycosides tested, to the vancomycin, tetracycline, and chloramphenicol, and E. durans 42G and E. faecalis 61B were resistant to erythromycin. The antimicrobial substances were sensitive to proteolytic enzymes and had good biochemical stability. E. durans 61A showed a good resistance to gastric and small intestinal secretions, but were more sensitive to the duodenal conditions. Considering the safety and the stability under simulated gastrointestinal tract, it appears that the bacteriocinogenic strain E. durans 61A is a good candidate for its application as novel probiotic strain in the food industry.

Anti-infective properties of bacteriocins: an update.

Bacteriocin production is a widespread phenomenon among bacteria. Bacteriocins hold great promise for the treatment of diseases caused by pathogenic bacteria and could be used in the future as alternatives to existing antibiotics. The anti-infective potential of bacteriocins for inhibiting pathogens has been shown in various food matrices including cheese, meat, and vegetables. However, their inhibition of pathogens in vivo remains unclear and needs more investigation, due mainly to difficulties associated with demonstrating their health benefits. Many bacteriocins produced by established or potential probiotic organisms have been evaluated as potential therapeutic agents and interesting findings have been documented in vitro as well as in a few in vivo studies. Some recent in vivo studies point to the efficacy of bacteriocin-based treatments of human and animal infections. While further investigation remains necessary before the possibilities for bacteriocins in clinical practice can be described more fully, this review provides an overview of their potential applications to human and veterinary health.

Immunomodulation by xylan and carrageenan-type polysaccharides from red seaweeds: Anti-inflammatory, wound healing, cytoprotective, and anticoagulant activities.

The immunomodulatory properties of the polysaccharides (carrageenan, xylan) from Chondrus crispus (CC), Ahnfeltiopsis devoniensis (AD), Sarcodiotheca gaudichaudii (SG) and Palmaria palmata (PP) algal species were studied. Using RAW264.7 macrophages, we investigated the proliferation and migration capacity of different extracts along with their immunomodulatory activities, including nitric oxide (NO) production, phagocytosis, and secretion of pro-inflammatory cytokines. Polysaccharides from C. crispus and S. gaudichaudii effectively mitigated inflammation and improved scratch-wound healing. Polysaccharide fractions extracted under cold conditions (25 °C), including CC-1A, SG-1A and SG-1B stimulated cell proliferation, while fractions extracted under hot conditions (95 °C), including CC-3A, CC-2B and A. devoniensis (AD-3A), inhibited cell proliferation after 48 h. Furthermore, RAW264.7 cells treated with the fractions CC-3A, AD-1A, and SG-2A significantly reduced LPS-stimulated NO secretion over 24 h. Phagocytosis was significantly improved by treatment with C. crispus (CC-2B, CC-3B) and A. devoniensis (AD-3A) fractions. RAW264.7 cells treated with the CC-2A and SG-1A fractions showed elevated TGF-ß1 expression without affecting TNF-α expression at 24 h. Polysaccharide fractions of A. devoniensis (ι/κ hybrid carrageenan; AD-2A, AD-3A) showed the highest anti-coagulation activity. CC-2A and SG-1A fractions enhanced various bioactivities, suggesting they are candidates for skin-health applications. The carrageenan fractions (CC-3A: λ-, µ-carrageenan, SG-2A: ν-, ι-carrageenan) tested herein showed great potential for developing anti-inflammatory and upscaled skin-health applications.

Neuromicrobiology, an emerging neurometabolic facet of the gut microbiome?

The concept of the gut microbiome is emerging as a metabolic interactome influenced by diet, xenobiotics, genetics, and other environmental factors that affect the host's absorption of nutrients, metabolism, and immune system. Beyond nutrient digestion and production, the gut microbiome also functions as personalized polypharmacy, where bioactive metabolites that our microbes excrete or conjugate may reach systemic circulation and impact all organs, including the brain. Appreciable evidence shows that gut microbiota produce diverse neuroactive metabolites, particularly neurotransmitters (and their precursors), stimulating the local nervous system (i.e., enteric and vagus nerves) and affecting brain function and cognition. Several studies have demonstrated correlations between the gut microbiome and the central nervous system sparking an exciting new research field, neuromicrobiology. Microbiome-targeted interventions are seen as promising adjunctive treatments (pre-, pro-, post-, and synbiotics), but the mechanisms underlying host-microbiome interactions have yet to be established, thus preventing informed evidence-based therapeutic applications. In this paper, we review the current state of knowledge for each of the major classes of microbial neuroactive metabolites, emphasizing their biological effects on the microbiome, gut environment, and brain. Also, we discuss the biosynthesis, absorption, and transport of gut microbiota-derived neuroactive metabolites to the brain and their implication in mental disorders.

Draft Genome Sequences of 18 Bacteroidetes Strains Isolated from a Human Stool Sample.

We announce the draft genome sequences of 12 Bacteroides, 4 Phocaeicola, and 2 Parabacteroides strains, among which was a newly isolated species, Bacteroidaceae bacterium UO.H1004. These isolates produce health-benefiting short-chain fatty acids (SCFAs) and the neurotransmitter γ-aminobutyric acid (GABA) in various concentrations.

A Two Bacteriocinogenic Ligilactobacillus Strain Association Inhibits Growth, Adhesion, and Invasion of Salmonella in a Simulated Chicken Gut Environment.

In this study, we aimed to develop a protective probiotic coculture to inhibit the growth of Salmonella enterica serovar Typhimurium in the simulated chicken gut environment. Bacterial strains were isolated from the digestive mucosa of broilers and screened in vitro against Salmonella Typhimurium ATCC 14028. A biocompatibility coculture test was performed, which identified two biocompatible strains, Ligilactobacillus salivarius UO.C109 and Ligilactobacillus saerimneri UO.C121 with high inhibitory activity against Salmonella. The cell-free supernatant (CFS) of the selected isolates exhibited dose-dependent effects, and the inhibitory agents were confirmed to be proteinaceous by enzymatic and thermal treatments. Proteome and genome analyses revealed the presence of known bacteriocins in the CFS of L. salivarius UO.C109, but unknown for L. saerimneri UO.C121. The addition of these selected probiotic candidates altered the bacterial community structure, increased the diversity of the chicken gut microbiota challenged with Salmonella, and significantly reduced the abundances of Enterobacteriaceae, Parasutterlla, Phascolarctobacterium, Enterococcus, and Megamonas. It also modulated microbiome production of short-chain fatty acids (SCFAs) with increased levels of acetic and propionic acids after 12 and 24 h of incubation compared to the microbiome challenged with S. Typhimurium. Furthermore, the selected probiotic candidates reduced the adhesion and invasion of Salmonella to Caco-2 cells by 37-39% and 51%, respectively, after 3 h of incubation, compared to the control. These results suggest that the developed coculture probiotic strains has protective activity and could be an effective strategy to control Salmonella infections in poultry.

Colistin A and colistin B among inhibitory substances of Paenibacillus polymyxa JB05-01-1.

Recently, we isolated and reported the antagonism of Paenibacillus polymyxa JB05-01-1 (P. polymyxa JB05-01-1) against Gram-negative bacteria. Here, we provide more insights and attribute the abovementioned antagonism to the production of colistins A and B, which were purified by Amberlite column exchange, C18 column hydrophobicity, superdex 75 16/60 gel filtration chromatography connected to fast protein liquid chromatography and identified by MALDI TOF/TOF, and manual nanospray analysis. The amount of colistin A and colistin B recovered from 500 ml of culture supernatant was about 0.05 mg. The specific activity and the average recovery of the eluted substances were 5,120 AU/mg and 1.1%, respectively. The minimal inhibitory concentrations of the purified colistins against Escherichia coli O157:H7 and Pseudomonas fluorescens LRC R73 were 0.13 and 0.62 µg/ml, respectively.

The Untapped Potential of Ginsenosides and American Ginseng Berry in Promoting Mental Health via the Gut-Brain Axis.

Despite the popularity of the ginseng (Panax) root in health research and on the market, the ginseng berry's potential remains relatively unexplored. Implementing ginseng berry cultivations and designing berry-derived products could improve the accessibility to mental health-promoting nutraceuticals. Indeed, the berry could have a higher concentration of neuroprotective and antidepressant compounds than the root, which has already been the subject of research demonstrating its efficacy in the context of neuroprotection and mental health. In this review, data on the berry's application in supporting mental health via the gut-brain axis is compiled and discussed.