Editorial: Insights into Microbe–Microbe Interactions in Human Microbial Ecosystems: Strategies to Be Competitive

The research work carried out by Editors of this research topic is being currently funded by project AGL2013-43770-R from Plan Nacional/Plan Estatal de I+D+i (Spanish Ministry of Economy and Competitiveness, MINECO) and by Grant GRUPIN14-043 from “Plan Regional de Investigación del Principado de Asturias.” Both, national and regional grants received cofounding from European Union FEDER funds. NS benefits from a Clarín postdoctoral contract (Marie Slodowska Curie European CoFund Program) cofinanced by Plan Regional de Investigación del Principado de Asturias, Spain.Peer reviewedPeer Reviewe

Non digestible oligosaccharides modulate the gut microbiota to control the development of leukemia and associated cachexia in mice

We tested the hypothesis that changing the gut microbiota using pectic oligosaccharides (POS) or inulin (INU) differently modulates the progression of leukemia and related metabolic disorders. Mice were transplanted with Bcr-Abl-transfected proB lymphocytes mimicking leukemia and received either POS or INU in their diet (5%) for 2 weeks. Combination of pyrosequencing, PCR-DGGE and qPCR analyses of the 16S rRNA gene revealed that POS decreased microbial diversity and richness of caecal microbiota whereas it increased Bifidobacterium spp., Roseburia spp. and Bacteroides spp. (affecting specifically B. dorei) to a higher extent than INU. INU supplementation increased the portal SCFA propionate and butyrate, and decreased cancer cell invasion in the liver. POS treatment did not affect hepatic cancer cell invasion, but was more efficient than INU to decrease the metabolic alterations. Indeed, POS better than INU delayed anorexia linked to cancer progression. In addition, POS treatment increased acetate in the caecal content, changed the fatty acid profile inside adipose tissue and counteracted the induction of markers controlling β-oxidation, thereby hampering fat mass loss. Non digestible carbohydrates with prebiotic properties may constitute a new nutritional strategy to modulate gut microbiota with positive consequences on cancer progression and associated cachexia. © 2015 Bindels et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.LBB is a Postdoctoral Researcher from the F.R.S.-FNRS (Fond National de la Recherche Scientifique, Belgium). NS is the recipient of a postdoctoral fellowship from the Spanish Ministry of Education, Culture and Sports. CD benefits from a Danone Institute grant. PDC is a research associate at FRS-FNRS (Fonds de la Recherche Scientifique, Belgium). GGM is a recipient of grants from FRS-FNRS and from FSR (UCL, Belgium). Financial support has been provided by a grant from the Walloon Region (Hydrasanté Project, convention 816875) and by a grant from the Spanish Ministry of Economy and Competitiveness (AGL2010-16525). NMD and PDC are recipients of grants from FNRS, and PDC is a recipient of ERC Starting Grant 2013 (European Research Council, Starting Grant 336452-ENIGMO). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer Reviewe

Impact on human health of microorganisms present in fermented dairy products: An overview

Fermented dairy products provide nutrients in our diet, some of which are produced by the action of microorganisms during fermentation. These products can be populated by a diverse microbiota that impacts the organoleptic and physicochemical characteristics foods as well as human health. Acidification is carried out by starter lactic acid bacteria (LAB) whereas other LAB, moulds, and yeasts become dominant during ripening and contribute to the development of aroma and texture in dairy products. Probiotics are generally part of the nonstarter microbiota, and their use has been extended in recent years. Fermented dairy products can contain beneficial compounds, which are produced by the metabolic activity of their microbiota (vitamins, conjugated linoleic acid, bioactive peptides, and gamma-aminobutyric acid, among others). Some microorganisms can also release toxic compounds, the most notorious being biogenic amines and aflatoxins. Though generally considered safe, fermented dairy products can be contaminated by pathogens. If proliferation occurs during manufacture or storage, they can cause sporadic cases or outbreaks of disease. This paper provides an overview on the current state of different aspects of the research on microorganisms present in dairy products in the light of their positive or negative impact on human health. © 2015 María Fernández et al.The work at the Spanish author’s laboratories was mainly financed through the projects AGL2010-16525 and INIA RM2010-00017-00-00 from the Ministry of Economy and Competitiveness (Spain).Peer Reviewe

Immune modulating capability of two exopolysaccharide-producing bifidobacterium strains in a wistar rat model

Fermented dairy products are the usual carriers for the delivery of probiotics to humans, Bifidobacterium and Lactobacillus being the most frequently used bacteria. In this work, the strains Bifidobacterium animalis subsp. lactis IPLA R1 and Bifidobacterium longum IPLA E44 were tested for their capability to modulate immune response and the insulin-dependent glucose homeostasis using male Wistar rats fed with a standard diet. Three intervention groups were fed daily for 24 days with 10% skimmed milk, or with 109 cfu of the corresponding strain suspended in the same vehicle. A significant increase of the suppressor-regulatory TGF-β cytokine occurred with both strains in comparison with a control (no intervention) group of rats; the highest levels were reached in rats fed IPLA R1. This strain presented an immune protective profile, as it was able to reduce the production of the proinflammatory IL-6. Moreover, phosphorylated Akt kinase decreased in gastroctemius muscle of rats fed the strain IPLA R1, without affecting the glucose, insulin, and HOMA index in blood, or levels of Glut-4 located in the membrane of muscle and adipose tissue cells. Therefore, the strain B. animalis subsp. lactis IPLA R1 is a probiotic candidate to be tested in mild grade inflammation animal models. © 2014 Nuria Salazar et al.This work was financed by the Spanish Ministry of Economy and Competitiveness (MINECO) and the FEDER European Union funds through the projects AGL2010-16525 and AGL2012-33278. The authors acknowledge Dr. Baltasar Mayo (IPLA-CSIC) for kindly supplying the strain IPLA E44.Peer Reviewe

Effect of an α-Tocopherol-Containing Antioxidant Parenteral Emulsion upon Gut Microbiota in Preterm Infants

Preterm babies are born with an immature intestine and are at higher risk for intestinal failure and needing for parenteral nutrition than full-term newborns. These babies show an altered intestinal microbiota, which may results of key importance for later health. However, there is a lack of information on effect of parenteral formulas upon the establishing infant microbiota. Moreover, the microbiota alterations present in preterm newborns have been related with an altered redox-potential which hinders the establishment of strict anaerobes. Thus, interventions aimed at reducing the oxidative stress in these infants, including those under parenteral nutrition, could also affect the intestinal microbiota composition. We assessed the effect upon the gut microbiota of the administration during 30 days of a lipid emulsion, containing ω3 polyunsaturated fatty acids and α-tocopherol, or a control emulsion containing soybean-bases lipids to parenterally-fed preterm newborns. In spite of its high antioxidant potential, the infants receiving the experimental fat emulsion showed a trend to increase of facultative anaerobes such as enterobacteria and specifically of Klebsiella. This study stresses the need of further work monitoring the impact of early-life parenteral nutrition on the establishment of the intestinal microbiota.This work was funded by the Luis Noé Fernández Award from Fundación Alimerka (Spain).Peer Reviewe

Induction of α-L-arabinofuranosidase activity by monomeric carbohydrates in Bifidobacterium longum and ubiquity of encoding genes

Bifidobacterium longum can be isolated from human faeces, some strains being considered probiotics. B. longum NIZO B667 produces an exo-acting α-L-arabinofuranosidase, AbfB, previously purified by us, that releases L-arabinose from arabinan and arabinoxylan. This activity was subjected to two-seven-fold induction by L-arabinose, D-xylose, L-arabitol and xylitol and to repression by glucose. Maximum activity was obtained at 48 h incubation except for D-xylose that was at 24 h. High concentrations (200 mM) of L-arabitol also caused repression of the arabinofuranosidase. A unique band of activity showing the same migration pattern as the purified AbfB was found in zymograms of cell free extracts, indicating that the activity was likely due to this sole enzyme. The assessment of the influence of inducers and repressors on the activity of AbfB and on the expression of the abfB gene by real time PCR indicated that regulation was transcriptional. DNA amplifications using a pair of degenerated primers flanking an internal fragment within α-L-arabinofuranosidase genes of the family 51 of glycoside hydrolases evidenced that these enzymes are widespread in Bifidobacterium. The aminoacidic sequences of bifidobacteria included a fragment of four to six residues in the position 136-141 that was absent in other microorganismsThis work was financed by European Union FEDER funds and the Spanish Plan Nacional de I + D (project AGL2004-06088-C02-01/ALI). L. Noriega was the recipient of a predoctoral fellowship from Fundación para la investigación Científica y Técnica (FICYT, Asturias, Spain). M. Gueimonde was funded by a Juan de la Cierva postdoctoral contract from the Spanish Ministry of Education and Science.Peer reviewe

Ubiquity and diversity of multidrug resistance genes in Lactococcus lactis strains isolated between 1936 and 1995

The presence and the nucleotide sequence of four multidrug resistance genes, lmrA, lmrP, lmrC, and lmrD, were investigated in 13 strains of Lactococcus lactis ssp. lactis, four strains of Lactococcus lactis ssp. cremoris, two strains of Lactococcus plantarum, and two strains of Lactococcus raffinolactis. Multidrug resistance genes were present in all L. lactis isolates tested. However, none of them could be detected in the strains belonging to the species L. raffinolactis and L. plantarum, suggesting a different set of multidrug resistance genes in these species. The analysis of the four deduced amino acid sequences established two different variants depending on the subspecies of L. lactis. Either lmrA, or lmrP, or both were found naturally disrupted in five strains, while full-length lmrD was present in all strainsThis work was financed by the European Union STREP project ACE-ART (FP6-506214).Peer reviewe

Red Wine Consumption Is Associated with Fecal Microbiota and Malondialdehyde in a Human Population

[Objectives] Red wine intake has been associated with a lower risk of cardiovascular disease; its polyphenol content is the primary cause of antioxidant and anti-inflammatory properties attributed to this beverage. However, the way in which these activities are exerted is not yet clear, although some authors have proposed that intestinal microbiota could be implicated.[Methods] The association between red wine intake, inflammation, and oxidative stress parameters and fecal microbial populations has been explored in 38 adult volunteers. Food intake was recorded by means of an annual food frequency questionnaire (FFQ). Energy, cholesterol, and ethanol intake were analyzed using the nutrient Food Composition Tables developed by Centro de Enseñanza Superior de Nutrición y Dietética (CESNID) and polyphenol intake was obtained from the Phenol-Explorer Database. Fecal levels of Akkermansia, Bacteroides, Bifidobacterium, Blautia coccoides group, Clostridium leptum group, Lactobacillus group, and Faecalibacterium prausnitzii were determined by quantitative polymerase chain reaction. Serum concentrations of C-reactive protein (CRP), malondialdehyde (MDA), total antioxidant capacity (TAC), cholesterol, triglycerides and glucose were analyzed by standard methods.[Results] Subjects with regular consumption of red wine (mean = 100 ml/day) had lower serum concentrations of MDA and lower fecal levels of B. coccoides, C. leptum, Bifidobacterium, and Lactobacillus. A positive association between MDA levels and B. coccoides and Lactobacillus was also found.[Conclusion] Regular consumption of red wine appears to be associated with a reduced serum lipoperoxidation in which the intestinal microbiota may be involved.This work was funded by Biopolis SL within the framework of the e-CENIT Project SENIFOOD from the Spanish Ministry of Science and Innovation.Peer Reviewe

Evaluation of the functional potential of Weissella and Lactobacillus isolates obtained from Nigerian traditional fermented foods and cow's intestine

The characterisation of 24 lactic acid bacteria (LAB) isolates from Nigerian traditional fermented dairy foods, including some cow's intestine isolates, was conducted in order to select isolates for potential use as probiotics. LAB isolates were identified by partial sequencing the 16S rRNA gene as belonging to the species Lactobacillus paracasei, Lactobacillus brevis and mainly Weissella confusa. At the end of a characterisation process, 2 L. paracasei and 2 W. confusa isolates were selected, and their resistance to a simulated gastrointestinal digestion and their ability to adhere to eukaryotic cell lines were assessed. The survival to the simulated gastrointestinal passage was higher when bacterial suspensions were made in skimmed milk (2.0 ± 0.8 log units reduction) or at the simulated gastric juice pH 3 (2.7 ± 0.9 log units reduction) than at pH 2.0 (5.5 ± 0.7 log units reduction). Adhesion of LAB to both intestinal and vaginal epithelial models was comparable or higher than that of the reference Lactobacillus rhamnosus GG. However, some of the isolates increased the adhesion of the pathogen Escherichia coli LMG2092 to HT-29 and HeLa monolayers. Overall, isolates L. paracasei UI14 and W. confusa UI7 are good candidates for further studying potential benefits that support their use as probiotics. This is one of the few articles reporting the characterisation and the probiotic potential of Weissella, although more studies are needed in order to establish their safety for potential probiotic applications. © 2011 Elsevier B.V.This work was financed by FEDER funds (European Union) and the Spanish Plan Nacional de I + D+I through the project AGL2009-09445. Borja Sánchez was the recipient of a postdoctoral Juan de la Cierva contract from the Spanish Ministry of Science and Innovation.Peer Reviewe

Two membrane proteins from Bifidobacterium breve UCC2003 constitute an ABC-type multidrug transporter

Intrinsic resistance to drugs is one of the main determining factors in bacterial survival in the intestinal ecosystem. This is mediated by, among others, multidrug resistance (MDR) transporters, membrane proteins which extrude noxious compounds with very different chemical structures and cellular targets. Two genes from Bifidobacterium breve encoding hypothetical membrane proteins with a high homology with members of the ATP-binding cassette (ABC) family of multidrug efflux transporters, were expressed separately and jointly in Lactococcus lactis. Cells co-expressing both proteins exhibited enhanced resistance levels to the antimicrobials nisin and polymyxin B. Furthermore, the drug extrusion activity in membrane vesicles was increased when both proteins were co-expressed, compared to membranes in which the proteins were produced independently. Both proteins were co-purified from the membrane as a stable complex in a 1 :1 ratio. This is believed to be the first study of a functional ABC-type multidrug transporter in Bifidobacterium and contributes to our understanding of the molecular mechanisms underlying the capacity of intestinal bacteria to tolerate cytotoxic compoundsThis work was financed by the European Union STREP project ACEART(FP6-506214), European Union FEDER funds, and the Spanish Plan Nacional de I+D (project AGL2004-06727-C02). J. A. Moreno was the recipient of a post-doctoral contract from CSIC (I3P programme), Spain. The work was also financially suported by the Department of Agriculture and Food FIRM programme (01/R&D/C/ 159), by the Higher Education Authority Programme for Research in Third Level Institutions, and by the SFI-funded Alimentary Pharmabiotic Centre.Peer reviewe