Lactobacillus plantarum P2R3FA Isolated from Traditional Cereal-Based Fermented Food Increase Folate Status in Deficient Rats

Folate deficiencies are widespread around the world. Promoting consumption of folate-rich foods could be a sustainable option to alleviate this problem. However, these foods are not always available. Cereals, being a staple food, could contribute to folate intake. They are fermented prior to consumption in many African countries, and fermentation can modify the folate content. In Ethiopia, injera is a widely consumed fermented flat bread. The main drivers of its fermentation are lactic acid bacteria (LAB). The aim of this work was to isolate and identify folate-producing LAB from injera fermented dough and to evaluate their ability to increase folate status after depletion in a rat model. Among the 162 strains isolated from 60 different fermentations, 19 were able to grow on a folate-free culture medium and produced 1 to 43 µg/L (24 h, 30 °C incubation). The four highest folate producers belonged to the Lactobacillus plantarum species. The most productive strain was able to enhance folate status after depletion in a rat model, despite the relatively low folate content of the feed supplemented with the strain. Folate-producing L. plantarum strain has potential use as a commercial starter in injera production

Lactobacillus plantarum P2R3FA Isolated from Traditional Cereal-Based Fermented Food Increase Folate Status in Deficient Rats

Folate deficiencies are widespread around the world. Promoting consumption of folate-rich foods could be a sustainable option to alleviate this problem. However, these foods are not always available. Cereals, being a staple food, could contribute to folate intake. They are fermented prior to consumption in many African countries, and fermentation can modify the folate content. In Ethiopia, injera is a widely consumed fermented flat bread. The main drivers of its fermentation are lactic acid bacteria (LAB). The aim of this work was to isolate and identify folate-producing LAB from injera fermented dough and to evaluate their ability to increase folate status after depletion in a rat model. Among the 162 strains isolated from 60 different fermentations, 19 were able to grow on a folate-free culture medium and produced 1 to 43 µg/L (24 h, 30 °C incubation). The four highest folate producers belonged to the Lactobacillus plantarum species. The most productive strain was able to enhance folate status after depletion in a rat model, despite the relatively low folate content of the feed supplemented with the strain. Folate-producing L. plantarum strain has potential use as a commercial starter in injera production

Lactobacillaceae and Cell Adhesion: Genomic and Functional Screening

The analysis of collections of lactic acid bacteria (LAB) from traditional fermented plant foods in tropical countries may enable the detection of LAB with interesting properties. Binding capacity is often the main criterion used to investigate the probiotic characteristics of bacteria. In this study, we focused on a collection of 163 Lactobacillaceace comprising 156 bacteria isolated from traditional amylaceous fermented foods and seven strains taken from a collection and used as controls. The collection had a series of analyses to assess binding potential for the selection of new probiotic candidates. The presence/absence of 14 genes involved in binding to the gastrointestinal tract was assessed. This enabled the detection of all the housekeeping genes (ef-Tu, eno, gap, groEl and srtA) in the entire collection, of some of the other genes (apf, cnb, fpbA, mapA, mub) in 86% to 100% of LAB, and of the other genes (cbsA, gtf, msa, slpA) in 0% to 8% of LAB. Most of the bacteria isolated from traditional fermented foods exhibited a genetic profile favorable for their binding to the gastrointestinal tract. We selected 30 strains with different genetic profiles to test their binding ability to non-mucus (HT29) and mucus secreting (HT29-MTX) cell lines as well as their ability to degrade mucus. Assays on both lines revealed high variability in binding properties among the LAB, depending on the cell model used. Finally, we investigated if their binding ability was linked to tighter cross-talk between bacteria and eukaryotic cells by measuring the expression of bacterial genes and of the eukaryotic MUC2 gene. Results showed that wild LAB from tropical amylaceous fermented food had a much higher binding capacity than the two LAB currently known to be probiotics. However their adhesion was not linked to any particular genetic equipment

Principaux mécanismes expliquant l'effet protecteur de trois aliments contre la génotoxicité digestive d'une amine hétérocyclique, l'IQ (étude chez le rat à flore contrôlée)

Les amines hétérocycliques sont des molécules cancérogènes produites lors de la cuisson des viandes et des poissons à partir d'acides aminés, de créatinine et de sucres. Nous avons démontré l'effet chimioprotecteur du chou de Bruxelles, de l'inuline et d'un lait fermenté vis-à-vis de la génotoxicité digestive d'une amine hétérocyclique, la 2-amino-3-méthylimidazo[4,5-f]quinoline (IQ), chez un modèle de rat à flore humaine. L'effet protecteur du chou de Bruxelles s'accompagne d'une modification de l'activité UDP-glucuronosyl transférase hépatique, enzyme majeure de détoxification de l'IQ ; celui de l'inuline d'un bouleversement de la flore intestinale, en particulier d'une diminution de l'activité ß-glucuronidase. Nous avons cherché si cette enzyme réactive l'IQ en hydrolysant ses dérivés glucuronidés formés dans le foie. Pour cela nous avons construit un mutant d'E. coli isogénique pour le gène uidA codant pour la ß-glucuronidase et monoassocié des rats sans germe, soit avec la souche sauvage, soit avec son mutant isogénique déficient. Le traitement à l'IQ induit deux fois plus de lésions dans le côlon des rats lorsqu'ils portent l'activité ß-glucuronidase, démontrant le rôle majeur de la ß-glucuronidase bactérienne dans l'effet génotoxique de l'IQ. Pour finir, nous avons cherché à élargir les connaissances du métabolisme bactérien de l'IQ en l'incubant in vitro, avec des flores fécales humaines ou des bactéries isolées de celle-ci et en utilisant une méthode d'analyse exhaustive du métabolisme, la RMN du proton. La 7-OH-IQ, métabolite de détoxification, a été détectée comme unique dérivé bactérien de l'IQ. Nous avons identifié 10 souches biodégradantes.Heterocyclic amines (HA) are carcinogenic compounds produced during meat and fish cooking from amino acids, creatinine and sugars. We found that Brussels sprouts, inulin and a fermented milk have a chemoprotective effect against the digestive genotoxicity of a HA, i.e. 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), using human microbiota associated-rats as an animal model. The protective effect of Brussels sprouts was associated with an induction of hepatic UDP-glucuronosyl transferase activity, the main IQ-detoxifying enzyme. Inulin effect was correlated with strong variation of the intestinal microbiota, especially with a reduction of ß-glucuronidase activity. In order to investigate if this enzyme could favour the reactivation of IQ by hydrolysing glucurono-conjugates formed in the liver, we constructed a ?-glucuronidase deficient mutant from a wild type "?-glucuronidase +" E. coli strain by deleting specifically the gene uidA encoding for this enzyme. Germ free rats were associated either with the wild type strain, or with the isogenic deficient mutant. We found that IQ treatment induced twice as much DNA damages in the colonocytes of the rats carrying the ?-glucuronidase activity than in their "ß-glucuronidase -" companions, thus demonstrating the pivotal role of bacterial ß-glucuronidase in the genotoxic effect of IQ. Finally, we investigated the action of the human intestinal microbiota on native IQ by incubating it with human fæcal samples and bacteria isolated from it in vitro. 1H-NMR spectroscopic analysis of crude incubation media showed that IQ is converted into a single harmless metabolite, the 7-OH-IQ. We have identified 10 biodegradative strains.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Pyrosequencing of Tagged 16S rRNA Gene Amplicons for Rapid Deciphering of the Microbiomes of Fermented Foods Such as Pearl Millet Slurries▿

Pearl millet slurries, mixed with groundnuts or not, were chosen as a model to investigate the feasibility of obtaining a rapid overview of community structure and population dynamics of fermented foods using pyrosequencing of tagged 16S rRNA gene amplicons. From 14 fermented samples collected either in a traditional small-scale processing unit in Burkina Faso or at laboratory scale, 137,469 sequences of bacterial 16S rRNA gene amplicons were characterized. Except for a few Proteobacteria, almost all the bacterial sequences were attributed to cultivable bacteria. This approach enabled 80.7% of the sequences to be attributed to a family and 70% to a genus but did not enable identification to the species level. The bacterial sequences were assigned to four phyla, with Firmicutes representing the highest diversity, followed by Proteobacteria, Actinobacteria, and Bacteroidetes, which were found only in the slurries prepared in traditional production units. Most of the Firmicutes were lactic acid bacteria, mainly represented by members of the Lactobacillus, Pediococcus, Leuconostoc, and Weissella genera, whose ratio varied from the onset to the end of the fermentation. The other bacteria present at the beginning of fermentation were generally no longer detected at the end, which is consistent with already-known patterns in the microbial ecology of fermented foods. In conclusion, this method seems very promising for rapid and preliminary microbial characterization in many samples of an unknown food sample, by determining numerous nucleic sequences simultaneously without the need for cloning and cultivation-dependent methods

Iron homeostasis in host and gut bacteria – a complex interrelationship

Iron deficiency is the most frequent nutritional deficiency in the world with an estimated 1.4 billion people affected. The usual way to fight iron deficiency is iron fortification, but this approach is not always effective and can have undesirable side effects including an increase in the growth and virulence of gut bacterial pathogens responsible for diarrhea and gut inflammation. Iron is mainly absorbed in the duodenum and is tightly regulated in mammals. Unabsorbed iron enters the colonic lumen where many microorganisms, referred to as gut microbiota, reside. Iron is essential for these bacteria, and its availability consequently affects this microbial ecosystem. The aim of this review is to provide further insights into the complex relationship between iron and gut microbiota. Given that overcoming anemia caused by iron deficiency is still a challenge today, gut microbiota could help identify more efficient ways to tackle this public health problem

Quantification of folate in the main steps of traditional processing of tef injera, a cereal based fermented staple food

Injera is an Ethiopian fermented flatbread preferably made from whole grain cereal (tef). Tef it is increasingly used to produce gluten-free pasta and bread, but the folate content of teff and products made from it remains unknown. Given that folate deficiencies lead to several health disorders, the aim of this study was to quantify folate in each of the three main steps of traditional processing of tef injera. Total folate contents of tef flour, fermented batter and injera were determined through microbiological assays using Lactobacillus rhamnosus (ATCC 7469). Folate content of tef flour was 8.7 mu g/100 g of dry matter content, which is in the same range as the richest cereals like oats. The increase in folate content due to fermentation was highly variable (60-148%). Cooking always led to folate losses, with a maximum of 52.8%. Altogether, injera processing increased folate retention between 38.0 and 121.8%. Folate content of injera was 14.3 mu g/100 g on fresh weight-basis. Tef injera can contribute up to 10% of the recommended nutrient intake of folate for children aged 1-3 and women of reproductive age. Although the folate content of teff is already high, future studies should focus on optimizing the folate content of injera

Lactic acid fermentation as a tool for increasing the folate content of foods

Folate is an essential micronutrient involved in numerous vital biological reactions. The dietary consumption of naturally occurring vitamin B9 is often inadequate in many countries, and supplementation or fortification programs (using synthetic folic acid) are implemented to alleviate folate deficiency. Other food-based alternatives are possible, such as the use of lactic acid bacteria (LAB) to synthesize folate during fermentation. Many studies have been conducted on this topic, and promising results were reported for some fermented dairy products. However, in other studies, folate consumption by LAB or rather low folate production were observed, resulting in fermented foods that may not significantly contribute to the recommended B9 intake. In addition, the optimum conditions for folate biosynthesis by LAB are still not clear. The aim of this review was thus to (i) clarify the ability of LAB to produce folate in food products, (ii) check if the production of folate by LAB in various fermented foods is sufficient to meet human vitamin B9 requirements and (iii) suggest ways to optimize folate production by LAB in fermented food products