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

Resumen del trabajo presentado a las III Jornadas Científicas CIAL Fórum, celebradas del 22 al 23 de noviembre de 2018 en el Instituto de Investigación en Ciencias de la Alimentación (CIAL)., La microbiota intestinal se ha señalado como un factor clave en la obesidad, dada su influencia en las funciones metabólicas e inmunológicas del hospedador. Desde el punto de vista de la composición estructural, la disbiosis de la microbiota intestinal asociada a obesidad, se ha relacionado con cambios en los ratios de los filos Firmicutes y Bacteroidetes. Estos cambios no han mostrado consistencia en estudios posteriores, si bien la obesidad parece estar relacionada con una menor diversidad bacteriana, una menor riqueza de genes y una alteración de las funciones metabólicas de la microbiota intestinal. Hoy en día, tanto el impacto de la composición y/o la funcionalidad de la microbiota como los mecanismos específicos de acción de esta microbiota en la obesidad, no están del todo claros. El principal objetivo de este trabajo ha sido determinar la importancia relativa de la composición taxonómica y/o funcional de la microbiota intestinal en la obesidad. La composición taxonómica de la microbiota fecal de individuos obesos (Ob) y normopeso (Np) se determinó por secuenciación masiva mediante la plataforma Illumina Seq. La amplificación del gen 16S rARN se realizó empleando como cebadores secuencias dirigidas hacia las regiones V3-V4 del gen. La caracterización funcional se determinó por medida de los ácidos grasos de cadena corta (AGCCs) por cromatografía líquida de alta eficacia (HPLC) y por medida de la concentración de amonio espectrofotométricamente. El análisis de los datos mostró que en el dominio Bacteria los filos más abundantes fueron Bacteroidetes (13%), Firmicutes (76%), Actinobacteria (10%) y Proteobacteria (1.8 %) sin encontrar diferencias significativas entre los individuos Ob y Np. El filo Verrumicrobia se encontró significativamente en mayor proporción en los individuos Np. A nivel de género, los grupos Collinsella, Alistipes, Clostridium sensu stricto, Clostridium XIVa, Romboutsia y Oscillibacter, entre otros, mostraron diferencias significativas entre ambos grupos de individuos. La diversidad bacteriana según el índice Chao1 fue significativamente mayor en los individuos Np a nivel de Filo y Familia. Respecto a la caracterización funcional, las muestras fecales de individuos Ob mostraron las mayores concentraciones de ácidos acético y butírico. Los resultados ponen de manifiesto que aún dentro de la gran variabilidad interindividual, la microbiota de individuos obesos se caracteriza por una mayor o menor presencia de determinados grupos microbianos y una mayor formación de determinados AGCCs respecto a la microbiota de individuos normopeso., Los autores agradecen la financiación otorgada por el Ministerio de Ciencia, Innovación y Universidades a través del proyecto AGL2016-75951-R., Peer reviewed

Resumen del trabajo presentado al IX Workshop on Probiotics, Prebiotics of the Spanish Society of Probiotics and Prebiotics (Sociedad Española de Probióticos y Prebióticos, SEPyP), celebrado en Zaragoza (España) del 15 al 16 de febrero de 2018., [Introduction] Ageing is characterized by an impairment of the homeostatic systems (nervous and immune systems) and consequently by a higher risk of morbidity and mortality. Nutritional intervention is one of the most used strategies to slow down this deterioration, and recently the supplementation with probiotics has been suggested as a possible way of improving these systems., [Objectives] This study evaluated the effects of the supplementation with Lactobacillus rhamnosus GG (LGG) on several behavioral and immune function parameters in a model of prematurely aging mice (PAM)., [Methods] Adult PAM and non-prematurely aging mice (NPAM), were divided into two groups, which received LGG (109 CFU/mice/day; lyophilized in skim milk and added to drink water) or skim milk without LGG (controls). After 2 weeks, mice were submitted to behavioural tests (anxiety-like behaviours and exploratory capacity). After this, and after an extra 2 week LGG supplementation, peritoneal leukocytes were collected and several immune functions (macrophage and lymphocyte chemotaxis, macrophage phagocytosis, natural killer cell activity and lymphoproliferative response to mitogens) were analyzed., [Results] The higher anxiety levels together with the lower exploratory activity observed in PAM compared with NPAM disappeared after LGG supplementation. Similar results were shown with PAM premature immunosenescence, and after 2 and 4 weeks of LGG intake an improvement of leukocyte functions was observed, with similar values to those found in NPAM. LGG counts reached 6 log DNA copy/g faeces in PAM and NPAM. However, there were no differences between the faecal microbiota
composition and metabolism of both groups (PAM and NPAM) at the starting of the assay and throughout 4 week LGG supplementation., [Conclusions] In conclusion, LGG ingestion improves nervous and immune functions in PAM. Since the parameters evaluated are health and ageing rate markers LGG could be useful for achieving a healthy longevity., This work was supported by FIS (PI15/01787) of Health Institute Carlos III – Regional Developing Aid European Funds (ISCIII-FEDER), MINEICO (AGL2016-75951-R, CDTI (ADAPTEA IDI-20150753) and CYTED (P916PTE0233)., Peer reviewed

Resumen del trabajo presentado al 10th Workshop on Probiotics and Prebiotics, celebrado en Las Palmas de Gran Canaria del 6 al 8 de febrero de 2019., [Background and Aims] The intestinal microbiota has been pointed out as a key factor in obesity, since it contributes to metabolic and inmunological homeostasis in the host. The dysbiosis of the gut microbiota linked to obesity has been related to a higher Firmicutes to Bacteroidetes ratio, a lower gene richness and an alteration of the metabolic functions of the gut microbiota. The main objective of this work was to outline the significance of the compositional and/or functional changes in the obese-associated intestinal microbiota., [Methods] The taxonomic composition of the fecal microbiota of obese (Ob) and normal weight (Np) individuals was determined by high-throughput sequencing analysis using the Illumina Seq platform.
Amplification of the 16S rRNA gene was carried out using as primers sequences directed towards the V3-V4 regions of the gene. Functional characterization was determined by measuring short chain fatty acids (SCFAs) by High Performance Liquid Chromatography (HPLC) and the ammonium concentration spectrophotometrically., [Results] Data analysis did not show significant differences between Ob and Np individuals in the dominant phyla Bacteroidetes (13%), Firmicutes (76%), Actinobacteria (10%) and Proteobacteria
(1.8%). Nevertheless, the proportion of Verrumicrobia was significantly higher in normal weight individuals (Np). At genus level, Collinsella, Alistipes, Clostridium, Clostridium XIVa, Romboutsia and Oscillibacter, among others, showed significant differences between both groups of individuals. Bacterial diversity according to the Chao1 index was significantly higher in Np individuals. Regarding the functional characterization, the fecal samples of Ob individuals showed the highest concentrations of acetic and butyric acids., [Conclusion] In spite of the great interindividual variability, the microbiota of obese individuals is characterized by a higher or lesser proportion of certain microbial groups and a higher formation of
SCFAs in relation to the microbiota of normal weight individuals., Finantial support by AGL2016-75951-R., Peer reviewed

Resumen del trabajo presentado al 10th Workshop on Probiotics and Prebiotics, celebrado en Las Palmas de Gran Canaria del 6 al 8 de febrero de 2019., [Background and Aims] Ageing is characterized by an impairment of the homeostatic (nervous and immune) systems and by changes in the intestinal microbiota. The objective of the study was to analyse differences in the gut microbiota and in several innate immune functions in old and prematurely ageing mice (PAM) when compared with adults, and the modulatory effects of supplementing with Lactobacillus rhamnosus GG., [Methods] Prematurely aging mice (PAM), old and adult mice (females ICR-CD1) were divided into two groups (N = 8-10), which received LGG (109 CFU/mice/day; lyophilized in skim milk and added to drink water) or skim milk without the probiotic LGG (controls). After 4 weeks of LGG supplementation, mice
were analysed for several innate immune parameters (chemotaxis, phagocytosis and natural killer activity). Faecal samples were collected for microbiota analysis at 0, 2 and 4 weeks of LGG
supplementation., [Results] Ageing in ICR-CD1 female mice was related with increase of Lactobacillus and Blautia coccoides/Eubacterium rectale and decrease of Akkermansia. LGG supplementation was related with changes in Bifidobacterium, Faecalibacterium and Ruminococcus counts. PAM and old mice showed lower values of the immune functions analysed than adult mice. After 4 weeks of LGG ingestion
all these functions improved, achieving values similar to those in adults., [Conclusion] L. rhamnosus GG can be considered a probiotic supplement useful for upgrading the immune system in ageing and, consequently, for reaching a healthy longevity., FIS (PI15/01787) of Health Institute Carlos III – Regional Developing Aid European Funds (ISCIII-FEDER), AGL2016-75951-R, CDTI (ADAPTEA IDI-20150753) and CYTED (P916PTE0233)., 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 microbiota of fermented dairy products contributes to the safety, flavor, and organoleptic qualities of the products. Moreover, metabolites obtained from the fermentation process enhance the milk nutritive value and digestibility, whereas dairy microorganisms could be the perfect carriers for reseeding the gut microbiota. The structural food matrix of fermented milk facilitates the delivery of viable microorganisms to the intestinal tract. Fermented dairy products may be beneficial to human health by improving lactose intolerance symptoms and for the production of bioactive compounds such as vitamins, gamma-amino butyric acid, exopolysaccharides, and bioactive peptides, among others. Also, fermented dairy products contribute to the modulation of the gut microbiota and the prevention of infections, inflammation, and cardiometabolic diseases. Furthermore, fermented dairy products constitute the hallmark of probiotics supply in the food market., This work was supported by the Spanish Ministry (Project AGL2016-75951-R), CDTI (INDEKA IDI-20190077) and CYTED (Project P917PTE0537/PCIN-2017-075)., Peer reviewed

This work assessed the significance of the taxonomic composition and/or metabolic activity of obese- microbiota by massive 16S rRNA gene sequencing of the faecal microbiome of obese and normoweight individuals. A total of 26 human faecal samples were analysed in this study. Faeces were collected from 13 normoweight (N) (body mass index = 18 - 25 kg m2) and 13 obese (O) adult volunteers (body mass index > 30 kg m2). All volunteers gave written informed consent to the protocol, which had been approved by the Clinical Ethics Committee of Hospital Ramón y Cajal with the code 394/14 and Spanish Council of Scientific Research (CSIC; Spain). Stool samples were collected under aseptic conditions in sterile and screw-top containers and immediately stored at –80°C. The taxonomic composition of the fecal microbiota of obese (Om) and normal weight (N) individuals was determined by massive sequencing using the Illumina Seq platform. Genomic DNA was extracted from faecal samples previously thawed at room temperature following the protocol described by Moles et al. (2013). DNA samples were subjected for massive 16S rDNA gene V3-V4 amplicon sequencing on the Ilumina MiqSeq platform. The primers were selected from previously described ones (Klindworth et al., 2013). Quality assessment was performed by the use of prinseq-lite program (Schmieder, et al., 2011) applying following parameters: min_length: 50; trim_qual_right: 30; trim_qual_type: mean; trim_qual_window:20; R1 and R2 from Illumina sequencing where joined using FLASH program (Magoc, et al., 2011) applying default parameters., We acknowledge financial support from the Spanish Ministry of Science and Innovation (AGL2016-75951-R)., Sequence Data: Trimmed and cleaned reads for each sample, according to parameters described in Methods section. When a sequence did not fit the minimum length or quality is removed from the dataset. This will generate a singleton file containing those reads without their pair.-- N denotes sequence data of faecal samples from normoweight individuals; OM denotes sequence data of faecal samples from obese individuals., 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 chapter covers methodologies currently in use for the selection and analysis of lactic acid bacteria (LAB) strains to be employed as starter cultures in dairy fermentations. The aspects covered are the methods for enumeration and identification of LAB strains and the evaluation of their technological properties for improving processing conditions and product quality during dairy fermentations. The selection of LAB strains based on health benefit properties and the conditions for the production and maintenance of dairy cultures are also addressed. The production of desirable and industrially robust dairy starter cultures can be achieved by choosing the desired phenotypic traits and the knowledge to select for these traits at the genotypic level. The analysis of a large number of strains for selecting specific properties requires high-throughput screening tests to progressively reduce the number of candidates. The advances in omics technologies and analytical instruments have provided the bases to improve the evaluation and selection of LAB strains that are able to restore the unique characteristics of traditional dairy products and to benefit human health., Financial support from Spanish Ministry of Science (Projects AGL2016-75951-R, PCIN-2017-075 and IDI-20190077) and CYTED (Strategic Project 917PTE0537) is acknowledged., 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