Diet has shaped microbiota profiles through human evolution. Traditional gut microbiomes are described to be driven by high levels of Prevotella. In the present, however, it is consistently described a lower microbial richness in urban industrialized populations compared with individuals living in rural settings, Bacteroides being predominant among urban-industrial gut microbiomes. Components of diet are highly influential in shaping the gut microbiota, being fiber, fat, proteins, polyphenols and micronutrients differentially metabolized by generalist and specialized microorganisms alone or through the phenomenon of cross-feeding. The progressive loss of microbial diversity over generations in industrialized societies along with the emerging increase of chronic non-transmissible diseases have been related to the decline in the consumption of dietary fiber. Diet and derived microbial metabolites have strong implications with the development of food associated diseases such as obesity and metabolic syndrome, malnutrition and eating disorders, intestinal inflammatory diseases and colorectal cancer, among others. Still, there is a need of further studies in order to identify microbiota-related biomarkers of risk for these disorders. In turn, healthy diets and specific nutritional interventions, including increase of dietary fiber and the consumption of probiotics and prebiotics, could be valuable for restoration of beneficial bacteria and microbiota diversity capable to shift from disease to health promoting states., This work was supported by the Spanish MINECO (Project AGL2016-75951-R) and CYTED (Project P916PTE0233)., Peer reviewed

The glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate, which initiates amino acid transamination during cheese ripening. This work has investigated the GDH activity in 39 wild isolates of Lactococcus lactis from raw milk cheeses. Only 25% of the isolates were GDH positive with NAD as the preferred cofactor. L. lactis IFPL953 showed the highest NAD-GDH activity. The GDH activity at the genetic level in the lactococcal isolates was analysed by PCR amplification of the gdh gene in genomic and plasmid DNA. The gdh gene arrangement of L. lactis IFPL953 in its plasmid location was similar to that in the reference strain GDHL. lactis TiL504, suggesting that both lactococci could harbour the same plasmid pGdh442 containing the gdh gene. L. lactis IFPL953 has previously demonstrated a remarkable α-ketoisovalerate decarboxylase activity, which along with its high GDH activity makes the strain particularly useful in enhancing cheese flavour formation., The authors acknowledge the funding from the Spanish MINEICO (AGL2012-35814, AGL2016-75951-R and P916PTE0233)., Peer Reviewed

The aim of the study was to evaluate the potential use of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) for fast and reliable detection of strains producing the lantibiotics nisin, lacticin 481 and lacticin 3147 in a large collection of lactococci. A total of one hundred lactococcal isolates from traditional ewe's and goat's raw milk cheeses were identified to the species level as Lactococcus lactis by MALDI-TOF MS based on comparison with lactococcal entries in the BioTyper database. Mass spectra in the range 2000–4000 Da of the identified isolates were compared to reference spectra of three lactococcal strains producing lacticin 481 (IFPL 330), lacticin 3147 (IFPL 105) and nisin (IFPL 503). Only eight isolates had mass spectra with peaks that could be unequivocally identified as lacticin 481 (2900.47 Da) or nisin (3330.31 Da). None of the assayed isolates matched the mass spectra corresponding to the two-peptide lacticin 3147 (2847.97 and 3306.29 Da). The results obtained by MALDI-TOF MS were genetically validated by amplification of the corresponding structural gene coding for lacticin 481, nisin and lacticin 3147. MALDI-TOF MS can be used as a fast and reliable technique to screen a large number of lactococcal isolates for the ability to produce the lantibiotics nisin, lacticin 481 and lacticin 3147., The authors acknowledge funding from the Spanish Ministry for Science and Innovation (AGL2012-35814, AGL2016-75951-R, RM2011-00003-00-00 and P916PTE0233), Peer Reviewed

This study investigates the mechanism by which food peptides are more effective than intact allergens in providing desensitization against food allergy. BALB/c mice sensitized to egg white (EW) were subjected to oral immunotherapy (OIT) with intact and pepsin-hydrolysed EW (EP). Treatment with EP was superior to that with EW in terms of reduction of anaphylaxis and levels of specific antibodies. OIT with EP, but not with EW, modulated the microbiota by restoring the levels of some members of the order Clostridiales (clusters IV and XIVa) that were affected by sensitization. Mice treated with EP exhibited upregulated intestinal expression of Il22 and Muc2, which encode for factors that contribute to reinforce the epithelial barrier function, as well as Aldh1a1, Aldh1a2, Csf2 and Tfgb1, that take part in the conversion of vitamin A into retinoic acid. Tolerance induced by EP paralleled the development of Foxp3 cells that simultaneously expressed RORγt., This study was funded by the projects AGL2017-88964-R and AGL2016-75951-R, and L P-R is recipient of a FPU grant (Ministerio de Ciencia, Innovación y Universidades)., Peer reviewed, Peer Reviewed

Pectic oligosaccharides (POS) derived from industrial byproducts, such as lemon peels (LP) and sugar beet pulp (SBP), have been reported to be non-digestible oligosaccharides an catalogued as promising candidates as prebiotics. This work has evaluated the selective fermentation of POS by potential probiotic Lactobacillus and Bifidobacterium strains. POS were fully characterized based on molecular weight and proportion of neutral and acidic oligosaccharides. All the tested probiotic strains reached better growth results when SBP POS were added to the growth media than LP POS. On the other hand, while Lactobacillus rhamnosus GG showed poor growth with LP POS-2, Bifidobacterium lactis Bb-12 was the only strain able to ferment these compounds. Lactic, acetic and formic acids were the main organic acids derived from POS fermentation by the assayed strains. The cocultures with Bacteroides fragilis did not modify the fermentation capability of the probiotic bacteria. This study has demonstrated that complex POS derived from lemon and sugar beet byproducts could be used as carbohydrate source by lactobacilli and bifidobacteria, showing the low-molecular-weight LP POS-2 a specific bifidogenic effect towards B. lactis. Results are promising for the development of synbiotic supplements., The authors acknowledge funding from the Spanish MINEICO (AGL2012-35814, AGL2016-75951-R and P916PTE0233), as well as for supporting this study in the framework of the research project “Advanced processing technologies for biorefineries” (reference CTQ 2014-53461-R), partially funded by the FEDER program of the European Union (“Unha maneira de facer Europa”). In addition, authors acknowledge the financial support received from “Xunta de Galicia” (Project GRC 2014/018 and Centro Singular de Investigación Biomédica “CINBIO”)., Peer reviewed

Lactococcus lactis contains a large number of key enzymes responsible for the formation of volatile compounds characteristic of cheese flavour. In the present work we have investigated the expression of genes codifying amino acid converting enzymes (AACE) and the formation of volatile compounds by L. lactis IFPL953 and its mutant lacking the hydroxy acid dehydrogenase PanE (L. lactis IFPL953ΔpanE). The growth in absence of isoleucine was the main induction factor in the expression of araT, bcaT, panE, and kivD. The expression of the gdh gene of L. lactis IFPL953ΔpanE increased remarkably during the stationary growth phase, particularly under isoleucine and valine starvation conditions. L. lactis IFPL953ΔpanE showed an enhanced formation of 2- and 3-methylbutanal and their corresponding alcohols and an increase in the formation of ketones. These findings contribute to a better knowledge of L. lactis AACE regulation and its potential application in cheese flavour formation., This study was funded by Spanish Ministry of Science (Grants AGL2016-75951-R and PCIN-2017-003)., Peer reviewed

Parts of this work were previously presented at the 21st, 22nd, and 23rd Spanish Congress of Clinical Microbiology and Infectious Diseases, the 29th European Congress of Clinical Microbiology and Infectious Diseases, the 6th Update on Fabry Disease, and 15th Annual Word Symposium of Lysosomal Diseases Research & Conference., Fabry disease is a rare X-linked lysosomal storage disorder resulting from deficient activity of α-galactosidase A, leading to the accumulation of glycosphingolipids such as globotriaosylsphingosine (lyso-Gb3). The gastrointestinal symptoms of this disease may be disabling, and the life expectancy of affected patients is shortened by kidney and heart disease. Our hypothesis was that lyso-Gb3 may modify the gut microbiota. The impact of a clinically relevant concentration of lyso-Gb3 on mono- or multispecies bacterial biofilms were evaluated. A complex bacterial community from the simulated transverse colon microbiota was studied using quantitative PCR to estimate different bacterial group concentrations and a HPLC was used to estimate short-chain fatty acids concentrations. We found that lyso-Gb3 increased the biofilm-forming capacity of several individual bacteria, including Bacteroides fragilis and significantly increased the growth of B. fragilis in a multispecies biofilm. Lyso-Gb3 also modified the bacterial composition of the human colon microbiota suspension, increasing bacterial counts of B. fragilis, among others. Finally, lyso-Gb3 modified the formation of short-chain fatty acids, leading to a striking decrease in butyrate concentration. Lyso-Gb3 modifies the biology of gut bacteria, favoring the production of biofilms and altering the composition and short-chain fatty-acid profile of the gut microbiota., JJAC is funded by an FPI grant from Spanish Ministry of Economics and Competitiveness (BES-2014-069007). The authors were further supported by FIS PI16/02057, PI18/01366, ISCIII-RETIC REDinREN RD016/0009 Fondos FEDER, Sociedad Española de Nefrología, Comunidad de Madrid B2017/BMD-3686 CIFRA2-CM, Miguel Servet MS14/00133 to MDSN and AGL2016-75951-R., Peer reviewed

Some strains of lactic acid bacteria (LAB) produce riboflavin, a water-soluble vitamin of the B complex, essential for human beings. Here, we have evaluated riboflavin (B2 vitamin) production by five Lactobacillus plantarum strains isolated from chicha, a traditional maize-based fermented alcoholic beverage from north-western Argentina and their isogenic riboflavin-overproducing derivatives previously selected using roseoflavin. A direct fluorescence spectroscopic detection method to quantify riboflavin production in bacterial culture supernatants has been tested. Comparison of the efficiency for riboflavin fluorescence quantification with and without prior HPLC fractionation showed that the developed method is a rapid and easy test for selection of B2 vitamin-producing strains. In addition, it can be used for quantitative detection of the vitamin production in real time during bacterial growth. On the basis of this and previous analyses, the L. plantarum M5MA1-B2 riboflavin overproducer was selected for in vitro and in vivo studies after being fluorescently labeled by transfer of the pRCR12 plasmid, which encodes the mCherry protein. The labeling did not affect negatively the growth, the riboflavin production nor the adhesion of the strain to Caco-2 cells. Thus, L. plantarum M5MA1-B2[pRCR12] was evaluated for its survival under digestive tract stresses in the presence of microbiota in the dynamic multistage BFBL gut model and in a murine model. After exposure to both models, M5MA1-B2[pRCR12] could be recovered and detected by the pink color of the colonies. The results indicated a satisfactory resistance of the strain to gastric and intestinal stress conditions but a low colonization capability observed both in vitro and in vivo. Overall, L. plantarum M5MA1-B2 could be proposed as a probiotic strain for the development of functional foods., This work was supported by the Spanish Ministry of Economy and Competitiveness (Grants AGL2016-75951-R, RTI2018-097114-B-I00, PCIN-2017-075, and PCIN-2017-003), the Ibero-American Program of Science and Technology for the Development (CYTED, Strategic Project Ref: 917PTE0537), SOURDOMICS Cost Action CA1801, and the European Cooperation in Science and Technology (COST).

In Press., [EN]: The study of the human microbiome has led to an exceptional increase in the current understanding of the importance of microbiota for health throughout all stages of life. Human microbial colonization occurs in the skin, genitourinary system and, mainly, in the oral cavity and intestinal tract. In these locations, the human microbiota establishes a symbiotic relationship with the host and helps maintain the physiological homeostasis. Lifestyle, age, diet and use of antibiotics are the main regulators of the composition and functionality of human microbiota. Recent studies have indicated the reduction in microbial diversity as one of the contributors to the development of diseases. In addition to phylogenetic diversity studies, further metagenomic studies are needed at the functional level of the human microbiome to improve our understanding of its involvement in human health., [ES]: El estudio del microbioma humano ha incrementado de manera excepcional el conocimiento actual del que disponemos sobre la importancia de la microbiota en la salud durante todas las etapas de la vida. La colonización microbiana humana ocurre en la piel, en el sistema genitourinario y, principalmente, en la cavidad oral y el tracto intestinal. En todos estos lugares, la microbiota humana establece una relación simbiótica con el hospedador y ayuda a mantener la homeostasis fisiológica. El estilo de vida, la edad, la dieta y el uso de antibióticos son los principales reguladores de la composición y la funcionalidad de la microbiota humana. Estudios recientes apuntan al descenso de la diversidad microbiana como uno de los aspectos que contribuye al desarrollo de enfermedades. Además de los estudios de diversidad filogenética, es necesario profundizar en estudios metagenómicos a nivel funcional del microbioma humano para mejorar el conocimiento sobre su participación en la salud humana., The author would like to thank the Ministry of Science, Innovation and Universities of Spain for funding this study through projects AGL2016-75951-R, PCIN-2017-075 and AGL2004-07285-C02., Peer reviewed

The in vitro development of representative gut microbiota from obese individuals has been approached in the present study by using a three-stage dynamic simulator of the human gut microbiota (BFBL Gut Model). During the stabilization period, aimed to reach the microbiota steady state, initial differences found between normal-weight (Nw) and obese (Ob) faecal samples were reproduced. The differentiation included lower values of Akkermansia, Enterococcus and Faecalibacterium and higher values of Lactobacillus for the Ob microbiota when compared with the Nw microbiota. The change of food ingredients to simulate a high consumption of readily-fermented carbohydrates and fructose-enriched beverages maintained these differences and additionally produced a decrease of Bifidobacterium in the Ob microbiota. Related to obesity metabolic signatures, a lower capacity to produce propionate was characteristic of the Ob microbiota under all the tested conditions. This could be useful in the selection of food ingredients for targeted production of propionate by the human gut microbiota prior to their assessment in nutritional intervention studies related to obesity., This research was funded by Spanish Ministry of Science and Innovation, grant number AGL2016-75951-R. Y.S. received a scholarship under the Graduate Student Overseas Study Program from South China Agricultural University., Peer reviewed

Intestinal microbiota seems to play a key role in obesity. The impact of the composition and/or functionality of the obesity-associated microbiota have yet to be fully characterized. This work assessed the significance of the taxonomic composition and/or metabolic activity of obese- microbiota by massive 16S rRNA gene sequencing of the fecal microbiome of obese and normoweight individuals. The obese metabolic activity was also assessed by in vitro incubation of obese and normoweight microbiotas in nutritive mediums with different energy content. We found that the microbiome richness and diversity of the two groups did not differ significantly, except for Chao1 index, significantly higher in normoweight individuals. At phylum level, neither the abundance of Firmicutes or Bacteroidetes nor their ratio was associated with the body mass index. Besides, the relative proportions in Collinsella, Clostridium XIVa, and Catenibacterium were significantly enriched in obese participants, while Alistipes, Clostridium sensu stricto, Romboutsia, and Oscillibacter were significantly diminished. In regard to metabolic activity, short-chain fatty acids content was significant higher in obese individuals, with acetate being the most abundant followed by propionate and butyrate. Acetate and butyrate production was also higher when incubating obese microbiota in mediums mimicking diets with different energy content; interestingly, a reduced capability of propionate production was associated to the obese microbiome. In spite of the large interindividual variability, the obese phenotype seems to be defined more by the abundance and/or the absence of distinct communities of microorganism rather than by the presence of a specific population., This work was supported by the Spanish Ministry of Science and Innovation (AGL2016-75951-R and PID2019-106071RB-I00 Grants)., We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI). We thank Marta Gil for her technical support., Peer reviewed

This article belongs to the Special Issue Analysis, Detection Technology and Safety Risk Assessment of Food Contaminants., For developing the recycling of fruit by-products from kiwano, a polysaccharide was extracted from kiwano (Cucumis metuliferus) peels, namely Cucumis metuliferus peels polysaccharide (CMPP), with the aim of investigating the potential beneficial effects. The composition of polysaccharides was analyzed by chemical methods. RAW264.7 macrophages cells and the microbiota dynamics simulator (BFBL gut model) were used for in vitro study. The result showed that CMPP mainly consists of glucuronic acid, arabinose, galactose and rhamnose. By intervening with RAW264.7 cells, CMPP promoted cell proliferation and showed immune-enhancing activity, which significantly (p < 0.05) induced the release of nitric oxide (NO), tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) at a concentration of 50 μg/mL. In addition, CMPP had an impact on the composition of the gut bacteria, increasing the growth of Akkermansia, Bacteroides, Bifidobacterium, Feacalibacterium, and Roseburia. During the intake period, acetic, butyric and propionic acids were all increased, especially (p < 0.05) in the descending colon. Moreover, a decrease in ammonia concentration (10.17 ± 0.50 mM in the ascending colon, 13.21 ± 1.54 mM in the transverse colon and 13.62 ± 0.45 mM in the descending colon, respectively) was observed. In summary, CMPP can be considered as a pectin, showed immunological activity and function of gut microbiota modulation. This study could be the scientific basis of developing kiwano peels as beneficial to human health., This research was funded by the Lingnan Modern Agricultural Science and Technology Guangdong Laboratory independent scientific research project (NZ2021032), the Key Area R&D Program of Guangdong Province (NO. 2019B020211002), the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme (2017), and the International Cooperation Program of SCAU (NO. 2019SCAUGH03). This research was funded by the Spanish Ministry of Science and Innovation (grant numbers AGL2016-75951-R and PID2019-106071RB-I00), Peer reviewed

This article belongs to the Section Nutraceuticals, Functional Foods, and Novel Foods., This study aimed to explore the anti-inflammatory and gut microbiota modulation potentials of flavonoid-rich fraction (PFF) extracted from Passiflora foetida fruits. The results showed that PFF markedly reduced the production of nitric oxide (NO), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) in LPS-stimulated RAW 264.7 cells. Meanwhile, PFF treatment also effectively decreased the phosphorylation levels of MAPK, PI3K/Akt, and NF-κB signaling-pathway-related proteins (ERK, JNK, p38, Akt, and p65). Moreover, PFF had an impact on microbial composition and metabolites in a four-stage dynamic simulator of human gut microbiota (BFBL gut model). Specifically, PFF exhibited the growth-promoting ability of several beneficial bacteria, including Bifidobacterium, Enterococcus, Lactobacillus, and Roseburia, and short-chain fatty acid (SCFA) generation ability in gut microbiota. In addition, spectroscopic data revealed that PFF mainly contained five flavonoid compounds, which may be bioactive compounds with anti-inflammatory and gut microbiota modulation potentials. Therefore, PFF could be utilized as a natural anti-inflammatory agent or supplement to health products., This research was funded by the Natural Science Foundation of China (31972157), Lingnan Modern Agricultural Science and Technology Guangdong Laboratory Independent Scientific Research Project (NZ2021032), Guangdong Provincial Key Laboratory of Food Quality and Safety (2020B1212060059), Spanish Ministry of Science and Innovation (AGL2016-75951-R, PID2019-106071RB-I00), South China Agricultural University Doctoral Students (overseas) Joint Education Programs (2018LHPY003), Natural Science Foundation of Guizhou Province (ZK[2023]451)., Peer reviewed

Pectic oligosaccharides (POS) derived from industrial byproducts, such as lemon peels (LP) and sugar beet pulp (SBP), have been reported to be non-digestible oligosaccharides an catalogued as promising candidates as prebiotics. This work has evaluated the selective fermentation of POS by potential probiotic Lactobacillus and Bifidobacterium strains. POS were fully characterized based on molecular weight and proportion of neutral and acidic oligosaccharides. All the tested probiotic strains reached better growth results when SBP POS were added to the growth media than LP POS. On the other hand, while Lactobacillus rhamnosus GG showed poor growth with LP POS-2, Bifidobacterium lactis Bb-12 was the only strain able to ferment these compounds. Lactic, acetic and formic acids were the main organic acids derived from POS fermentation by the assayed strains. The cocultures with Bacteroides fragilis did not modify the fermentation capability of the probiotic bacteria. This study has demonstrated that complex POS derived from lemon and sugar beet byproducts could be used as carbohydrate source by lactobacilli and bifidobacteria, showing the low-molecular-weight LP POS-2 a specific bifidogenic effect towards B. lactis. Results are promising for the development of synbiotic supplements., Agencia Estatal de Investigación | Ref. AGL2016-75951-R, Ministerio de Economía y Competitividad | Ref. P916PTE0233, Xunta de Galicia | Ref. GRC 2014/018