BacteriaIntestine, SmallIntestinesIntestine, LargeGram-Negative BacteriaGram-Positive BacteriaBacteria, AnaerobicMolecular Sequence DataRNA, Ribosomal, 16SIntestinal MucosaBacteria, AerobicDNA, BacterialBacterial ProteinsPhylogenyEscherichia coliDNA, RibosomalJejunumSequence Analysis, DNAIntestinal AbsorptionWater MicrobiologyIleumBacterial Physiological PhenomenaAnti-Bacterial AgentsGram-Negative Aerobic BacteriaGram-Negative Anaerobic BacteriaColony Count, MicrobialSoil MicrobiologyAmino Acid SequenceGenes, BacterialSeawaterRNA, BacterialBase SequenceGene Expression Regulation, BacterialSulfur-Reducing BacteriaCulture MediaBacterial AdhesionSpecies SpecificityAnaerobiosisSymbiosisGenome, BacterialGenes, rRNAColonDuodenumDigestive SystemCecumGastrointestinal TractFecesBase CompositionEnterobacteriaceaeBiodegradation, EnvironmentalFermentationPseudomonasGerm-Free LifeBacteroidesFresh WaterHydrogen-Ion ConcentrationCloning, MolecularBacteriological TechniquesMicrovilliIntestinal NeoplasmsBacterial InfectionsGammaproteobacteriaBiofilmsMicrobial Sensitivity TestsIntestinal DiseasesAerobiosisPolymerase Chain ReactionEnterocytesBacterial Typing TechniquesVirulenceGeologic SedimentsFatty AcidsProteobacteriaPseudomonas aeruginosaVibrioSequence Homology, Amino AcidStaphylococcus aureusMutationSalmonella typhimuriumMicrobial ViabilitySwineStreptococcusTemperatureBetaproteobacteriaProbioticsPlasmidsOxidation-ReductionCytophagaRNA, MessengerKineticsMicroscopy, ElectronMetagenomeClostridiumTime FactorsBacillusMice, Inbred C57BLEubacteriumSequence AlignmentLiverStomach