Graciela Font

Probiotics for everyone! The novel immunobiotic lactobacillus rhamnosus CRL1505 and the beginning of social probiotic programs in Argentina

Lactobacillus rhamnosus CRL1505 (Lr1505) stimulates immune responses in the gut and in the respiratory tract and improves resistance against Salmonella typhimurium and Streptococcus pneumoniae infections in immunocompetent and immunocompromised mice. Considering that respiratory infectious diseases continue to be a major cause of death among preschool children in developing countries, the aim of the present study was to evaluate the effect of Lr1505 on the health of children. A randomized-controlled double-blind clinical trial in 298 healthy children (2-5 years old), attending daycare centers was performed. Yogurt containing Lr1505 was administered to children for 6 months (five times a week). Results were statistically compared with those of children from the same community that received a placebo yogurt (without probiotic). Administration of Lr1505 to young children reduced the incidence of infections: 66% of children in the placebo group presented symptoms of infection while only 34% of cases were detected in the Lr1505 group. Significant differences ( P <0.05) were detected in the incidence of intestinal infections, upper respiratory tract infections and angina when placebo and Lr1505 groups were compared. Children fed Lr1505 experienced fewer fevers and needed fewer antibiotics than those receiving the placebo. The protective effect of Lr1505 was associated with increased levels of mucosal IgA antibodies. Lr1505 is a promising resource for the development of prevention strategies against mucosal infections that could be effective tools for medical application. This new probiotic strain has been included into official Nutritional Programs in Argentina and it is given to more than 200 thousand children. This project has encouraged local milk production, thanks to the constant demand of probiotic yogurt containing L. rhamnosus CRL1505 by provincial governments, while incorporating innovation to small and medium enterprises.

Draft Genome Sequence of Lactobacillus reuteri Strain CRL 1098, an Interesting Candidate for Functional Food Development

ABSTRACT We report here the draft genome sequence of Lactobacillus reuteri strain CRL 1098. This strain represents an interesting candidate for functional food development because of its proven probiotic properties. The draft genome sequence is composed of 1,969,471 bp assembled into 45 contigs and an average G+C content of 38.8%.

Cobalamin production by Lactobacillus coryniformis : biochemical identification of the synthetized corrinoid and genomic analysis of the biosynthetic cluster

BackgroundDespite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. Vitamin B12 (Cobalamin) is a complex compound that is only naturally produced by bacteria and archea. It has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the B-group, as vitamin B12. In this context, the goal of the present paper was to evaluate and characterize the production of vitamin B12 in Lactobacillus coryniformis CRL 1001, a heterofermentative strain isolated from silage.ResultsCell extract of L. coryniformis CRL 1001, isolated from silage, is able to correct the coenzyme B12 requirement of Salmonella enterica serovar Typhimurium AR 2680 in minimal medium. The chemical characterization of the corrinoid-like molecule isolated from CRL 1001 cell extract using HPLC and mass spectrometry is reported. The majority of the corrinoid produced by this strain has adenine like Coα-ligand instead 5,6-dimethylbenzimidazole. Genomic studies revealed the presence of the complete machinery of the anaerobic biosynthesis pathway of coenzyme B12. The detected genes encode all proteins for the corrin ring biosynthesis and for the binding of upper (β) and lower (α) ligands in one continuous stretch of the chromosome.ConclusionsThe results here described show for the first time that L. coryniformis subsp. coryniformis CRL 1001 is able to produce pseudocobalamin containing adenine instead of 5,6-dimethlbenzimidazole in the Coα-ligand. Genomic analysis allowed the identification and characterization of the complete de novo biosynthetic pathway of the corrinoid produced by the CRL 1001 strain.

Artisanal tanneries: Potential application of inoculants formulated with lactic acid bacteria

In artisanal tanneries, the skins are immersed in cereals fermented by natural microbial flora in order to reduce the pH of the skin, an essential condition for carrying out the final step. The environmental thermal variation alters the fermentation process and affects the quality of the final product. The aim of this work was to isolate lactic acid bacteria from cereals mixture fermented in an artisanal tannery and to evaluate in vitro the acidifying activity of the strains as a first step for the formulation of a starter culture. In most samples, a prevalence of cocci (95%) was observed with respect to bacilli. The best acidifying strains were identified by phenotypic and genotypic techniques as Enterococcus faecium CRL 1943 (rapid acidification at 37 °C) and Leuconostoc citreum CRL 1945 (high acidifying activity at 18 °C). In addition, the biomass production of the selected strains was analyzed at free and controlled pH (bioreactors 1.5 L). The production of biomass was optimal at controlled pH, with a higher growth (0.5–1.1 log units). Both strains were compatible, allowing their inclusion in a mixed culture. These lactic strains could contribute to the systematization of the tanning process.

Novel Pathway for Corrinoid Compounds Production in Lactobacillus

Vitamin B12 or cobalamin is an essential metabolite for humans, which makes it an interesting compound for many research groups that focus in different producer-strains synthesis pathways. In this work, we report the influence of key intermediaries for cobalamin synthesis added to the culture medium in two Lactobacillus (L.) strains, L. reuteri CRL 1098 and L. coryniformis CRL 1001. Here, we report that addition of Co2+ and 5,6-dimethylbenzimidazole increased the corrinoid compounds production in both strains while addition of L-threonine increased only the corrinoid compounds production by CRL 1001 strain. Then, we purified and characterized by LC-MS the corrinoid compounds obtained. Physiological studies besides in silico analysis revealed that L. reuteri CRL 1098 and L. coryniformis CRL 1001 follow different pathways for the last steps of the corrinoid compounds synthesis.