Microbial colonization of mammals is an evolution-driven process that modulate host physiology, many of which are associated with immunity and nutrient intake. Here, we report that colonization by gut microbiota impacts mammalian brain development and subsequent adult behavior. Using measures of motor activity and anxiety-like behavior, we demonstrate that germ free (GF) mice display increased motor activity and reduced anxiety, compared with specific pathogen free (SPF) mice with a normal gut microbiota. This behavioral phenotype is associated with altered expression of genes known to be involved in second messenger pathways and synaptic long-term potentiation in brain regions implicated in motor control and anxiety-like behavior. GF mice exposed to gut microbiota early in life display similar characteristics as SPF mice, including reduced expression of PSD-95 and synaptophysin in the striatum. Hence, our results suggest that the microbial colonization process initiates signaling mechanisms that affect neuronal circuits involved in motor control and anxiety behavior.developmental programming | microbiome | basal ganglia | cognitive behavior | synapse

The cellular attachment receptor for adenovirus (Ad), Coxsackie adenovirus receptor (CAR), required for delivery of Ad into primary cells, is not present on all cell types, thus restricting Ad-gene delivery systems. To circumvent this constrain, a transgenic mouse has been generated that expresses a truncated human CAR in all tissues analyzed. These mice allowed efficient in vitro infections at low multiplicities into lymphoid, myeloid, and endothelial cells. Furthermore, in vivo administration of Ad-vectors results in infection of macrophages, lymphocytes, and endothelial cells. In addition, tail vein injection resulted in targeting of virus into previously inaccessible areas, such as the lung and the capillaries of the brain. The CAR transgenic mice will be useful for rapid functional genomic analysis in vivo, for testing the efficacy of gene therapy procedures or as a source of easily transducible cells.

Broad-range 16s rDNA PCR (BR-PCR) applied to DNA from 32 clinical enterococcal isolates and 12 other enterococci from a clinical reference collection followed by species-specific hybridization analysis identified 25 strains of Enterncoccus faecalis and 19 Enterncoccus species. Randomly amplified polymorphic DNA (RAPD) analysis using UPGMA clustering on the same material revealed four different clusters at a similarity level of 49%. Based on partial 165 rDNA sequence analysis of variable regions V4 and V9, it was possible to divide the 19 type strains specifying the genus Enterncoccus into 12 different 16s rDNA species groups. The type strain distribution then served as a template for the analysis of the other 44 strains which were assigned to four different species groups (it-d) based on their 165 rDNA motifs. There was good agreement with the RAPD clusters. Species group a was an individual species line containing 25 strains that were identified as E. faecalis. Group b also represented an individual species line of 12 strains identified as Em faecium. The remaining seven strains that formed species groups c and d could not be fully identified to species by this analysis. It was concluded that BR-PCR of 16s rDNA followed by partial sequence analysis of the PCR products is a reliable technique for the identification and classification of enterococci. Further division of unresolved species groups should be achievable if regions other than V4 and V9 of 165 rDNA are also analysed.

To execute different biological functions, the expression pattern of immunoglobulin heavy chain genes (IgH) is altered during B lymphocyte differentiation. Early in B cell differentiation, it is assumed that the heavy chain promoter and the intragenic enhancer (E mu) ensure VDJ recombination. This leads to the expression of the immunoglobulin receptor on the cell surface. An additional strong enhancer in the far 3' end of the IgH locus has, however, prompted a re-evaluation of the regulation of immunoglobulin gene expression. To define the temporal and spatial regulation of the IgH 3' enhancer, transgenic mice harboring an enhancer-dependent reporter gene construct were generated. Here we demonstrate that IgH 3' enhancer activity is largely restricted to activated immunocompetent B cells. Furthermore, the enhancer can be transactivated following mitogen stimulation with lipopolysaccharide and 12-O-tetradecanoylphorbol 13-acetate. We propose a model whereby 3' enhancer activation is linked to the activation of resting immunocompetent B cells. The implications of the enhancer being active in late B lymphocyte differentiation, when heavy chain class switching occurs, are discussed.

Even if not all outcomes for patients with an HAI can be explained by the HAI itself, the increase in inpatient days, readmissions, associated costs, and higher mortality rates are quite notable.