ABSTRACT
AIMS: The aim of this study was to evaluate the impact of the administration of microencapsulated Lactobacillus plantarum CRL 1815 with two combinations of microbially derived polysaccharides, xanthan : gellan gum (1%:0·75%) and jamilan : gellan gum (1%:1%), on the rat faecal microbiota. METHODS AND RESULTS: A 10-day feeding study was performed for each polymer combination in groups of 16 rats fed either with placebo capsules, free or encapsulated Lact. plantarum or water. The composition of the faecal microbiota was analysed by fluorescence in situ hybridization and temporal temperature gradient gel electrophoresis. Degradation of placebo capsules was detected, with increased levels of polysaccharide-degrading bacteria. Xanthan : gellan gum capsules were shown to reduce the Bifidobacterium population and increase the Clostridium histolyticum group levels, but not jamilan : gellan gum capsules. Only after administration of jamilan : gellan gum-probiotic capsules was detected a significant increase in Lactobacillus-Enterococcus group levels compared to controls (capsules and probiotic) as well as two bands were identified as Lact. plantarum in two profiles of ileum samples. CONCLUSIONS: Exopolysaccharides constitute an interesting approach for colon-targeted delivery of probiotics, where jamilan : gellan gum capsules present better biocompatibility and promising results as a probiotic carrier. SIGNIFICANCE AND IMPACT OF STUDY: This study introduces and highlights the importance of biological compatibility in the encapsulating material election, as they can modulate the gut microbiota by themselves, and the use of bacterial exopolysaccharides as a powerful source of new targeted-delivery coating material.
Subject(s)
Drug Carriers/chemistry , Feces/microbiology , Lactobacillus plantarum , Metagenome , Probiotics/administration & dosage , Animals , Bifidobacterium/genetics , Bifidobacterium/growth & development , Biodiversity , Capsules , Clostridium histolyticum/genetics , Clostridium histolyticum/growth & development , Electrophoresis, Gel, Pulsed-Field , Female , Gastrointestinal Tract/microbiology , Polymers/chemistry , Polysaccharides, Bacterial/chemistry , RNA, Ribosomal, 16S/genetics , Rats , Rats, WistarABSTRACT
A novel moderately halophilic bacterium belonging to the genus Halomonas was isolated from brine samples collected from Ezzemoul sabkha in north-eastern Algeria. The cells of strain 5-3(T) were Gram-negative, rod-shaped and non-motile. The strain was catalase- and oxidase-positive and produced an exopolysaccharide. Growth occurred at NaCl concentrations of 5-25% (optimum at 7.5%), at 30-50 degrees C (optimum at 37-40 degrees C) and at pH 6.0-9.0 (optimum at pH 7.5). The major fatty acids were C(12:0) 3-OH, C(16:1)omega7c/iso-C(15:0) 2-OH, C(16:0), C(18:1)omega7c and C(19:0)omega8c cyclo. The G+C content of the genomic DNA was 57.0 mol% (T(m)). The affiliation of strain 5-3(T) with the genus Halomonas was confirmed by 16S rRNA gene sequence comparisons. The most closely related species was Halomonas halmophila, which showed a 16S rRNA gene sequence similarity of 99.7%. However, the level of DNA-DNA relatedness between the novel isolate and the related Halomonas species was less than 31.4%. On the basis of the data from this polyphasic study, strain 5-3(T) represents a novel species of the genus Halomonas, for which the name Halomonas sabkhae sp. nov. is proposed. The type strain is 5-3(T) (=CECT 7246(T)=DSM 19122(T)=LMG 24084(T)).
