Our knowledge about the gut microbiota of pigs is still scarce, despite the importance of these animals for biomedical research and agriculture. Here, we present a collection of cultured bacteria from the pig gut, including 110 species across 40 families and nine phyla. We provide taxonomic descriptions for 22 novel species and 16 genera. Meta-analysis of 16S rRNA amplicon sequence data and metagenome-assembled genomes reveal prevalent and pig-specific species within Lactobacillus, Streptococcus, Clostridium, Desulfovibrio, Enterococcus, Fusobacterium, and several new genera described in this study. Potentially interesting functions discovered in these organisms include a fucosyltransferase encoded in the genome of the novel species Clostridium porci, and prevalent gene clusters for biosynthesis of sactipeptide-like peptides. Many strains deconjugate primary bile acids in in vitro assays, and a Clostridium scindens strain produces secondary bile acids via dehydroxylation. In addition, cells of the novel species Bullifex porci are coccoidal or spherical under the culture conditions tested, in contrast with the usual helical shape of other members of the family Spirochaetaceae. The strain collection, called ‘Pig intestinal bacterial collection’ (PiBAC), is publicly available at www.dsmz.de/pibac and opens new avenues for functional studies of the pig gut microbiota.

To gain insight into the regulatory mechanisms of sugar signaling in plants, the effect of derivatives of the transport sugar sucrose (Suc), the Suc isomers palatinose and turanose, and the Suc analog fluoro-Suc were tested. Photo-autotrophic suspension culture cells of tomato (Lycopersicon peruvianum) were used to study their effect on the regulation of marker genes of source and sink metabolism, photosynthesis, and the activation of mitogen-activated protein kinases (MAPKs). Suc and glucose (Glc) resulted in reverse regulation of source and sink metabolism. Whereas the mRNA level of extracellular invertase (Lin6) was induced, the transcript level of small subunit of ribulose bisphosphate carboxylase (RbcS) was repressed. In contrast, turanose, palatinose, and fluoro-Suc only rapidly induced Lin6 mRNA level, whereas the transcript level of RbcS was not affected. The differential effect of the metabolizable and non-metabolizable sugars on RbcS mRNA regulation was reflected by the fact that only Suc and Glc inhibited photosynthesis and chlorophyll fluorescence. The activation of different signal transduction pathways by sugars was further supported by the analysis of the activation of MAPKs. MAPK activity was found to be strongly activated by turanose, palatinose, and fluoro-Suc, but not by Suc and Glc. To analyze the role of sugars in relation to pathogen perception, an elicitor preparation of Fusarium oxysporum lycopersici was used. The strong activation of MAPKs and the fast and transient induction of Lin6 expresssion by the fungal elicitor resembles the effect of turanose, palatinose, and fluoro-Suc and indicates that non-metabolizable sugars are sensed as stress-related stimuli.

Fucosyltransferases (FucTs) are essential tools for the synthesis of fucosylated glycoconjugates. Multistep enzyme catalysis of fucosylated glycans is not limited as long as isolated and well-characterized FucTs are available. The present paper introduces a novel bacterial α1,2-FucT of the glycosyltransferase family 11 encoded by the gene wbgL in the E. coli O126 genome, which only displays 25–30% homology to previously published α1,2-FucTs. A tailor made cloning and expression strategy allowed the successful production of active soluble enzyme in the cytoplasm of E. coli BL21(DE3) and E. coli JM109(DE3), respectively. The lack of a DxD motif and its high activity without divalent metal ions suggests that WbgL belongs to the GT-B fold superfamily. Substrate screening revealed the highest activity for β4-linked galactoside acceptor substrates, such as lactose and lactulose, making WbgL unique among other characterized α1,2-FucTs. Based on its excellent kinetic efficiency for lactose, we present here a sequential reaction strategy for the synthesis of α1,2-fucosyllactose in one pot including the synthesis of the donor substrate 3,3′-Diaminobenzidine (GDP)-β-l-fucose by the bifunctional l-fucokinase/GDP-β-l-Fuc pyrophosphorylase of Bacteroides fragilis 9343.