We developed a novel surface display system based on the use of bacterial spores. A protein of the Bacillus subtilis spore coat, CotB, was found to be located on the spore surface and used as fusion partner to express the 459-amino-acid C-terminal fragment of the tetanus toxin (TTFC). Western, dot blot and fluorescentactivated cell sorting analyses were used to monitor TTFC surface expression on purified spores. We estimated that more than 1.5 ؋ 10 3 TTFC molecules were exposed on the surface of each spore and recognized by TTFC-specific antibodies. The efficient surface presentation of the heterologous protein, together with the simple purification procedure and the high stability and safety record of B. subtilis spores, makes this spore-based display system a potentially powerful approach for surface expression of bioactive molecules.

Background & Aims Inducible chitinase 3-like-1 (CHI3L1) is expressed by intestinal epithelial cells (IECs) and adheres to bacteria under conditions of inflammation. We performed a structure–function analysis of the chitin-binding domains (CBDs) encoded by the chiA gene, which mediates the pathogenic effects of adherent invasive Escherichia coli (AIEC). Methods We created AIEC (strain LF82) with deletion of chiA (LF82-ΔchiA) or that expressed chiA with specific mutations. We investigated the effects of infecting different IEC lines with these bacteria, compared with non-pathogenic E coli; chitinase activities were measured using the colloidal chitin-azure method. Colitis was induced in C57/Bl6 mice by administration of dextran sodium sulfate (DSS), and mice were given 108 bacteria for 15 consecutive days by gavage. Stool/tissue samples were collected and analyzed. Results LF82-ΔchiA had significantly less adhesion to IEC lines than LF82. Complementation of LF82-ΔchiA with the LF82 chiA gene, but not chiA from non-pathogenic (K12) E coli, increased adhesion. We identified 5 specific polymorphisms in the CBD of LF82 ChiA (at amino acids 362, 370, 378, 388, and 548) that differ from chiA of K12 and were required for LF82 to interact directly with IECs. This interaction was mediated by an N-glycosylated asparagine in CHI3L1 (amino acid 68) on IECs. Mice infected with LF82, or LF82-ΔchiA complemented with LF82 chiA, developed more severe colitis following administration of DSS than mice infected with LF82-ΔchiA or LF82 that expressed mutant forms of chiA. Conclusion AIEC adhere to an N-glycosylated CHI3L1 on IEC via the CBD of chiA. This mechanism of promotes pathogenic effects of AIEC in mice with colitis.

Background The 2010 Affordable Care Act relies on Federally Qualified Health Centers (FQHC) and FQHC look-alikes (look-alikes) to provide care for newly insured patients, but ties increased funding to demonstrated quality and efficiency. Purpose To compare FQHC and look-alike physician performance with private practice primary care physicians (PCPs) on ambulatory care quality measures. Methods The study was a cross-sectional analysis of visits in the 2006–2008 National Ambulatory Medical Care Survey. Performance of FQHCs and Look-alikes on 18 quality measures was compared with private practice PCPs. Data analysis was completed in 2011. Results Compared to private practice PCPs, FQHCs and look-alikes performed better on 6 measures (p<0.05), worse on diet counseling in at-risk adolescents (26 % vs. 36%, p=0.05), and no differently on 11 measures. Higher performance occurred in: ACE inhibitors use for congestive heart failure (51% vs. 37%, p=0.004); aspirin use in coronary artery disease (CAD) (57% vs. 44%, p=0.004); beta blocker use for CAD (59% vs. 47%, p=0.01); no use of benzodiazepines in depression (91% vs. 84%, p=0.008); blood pressure screening (90% vs. 86%, p<0.001); and screening electrocardiogram (EKG) avoidance in low-risk patients (99% vs. 93%, p<0.001). Adjusting for patient characteristics yielded similar results except private practice PCPs no longer performed better on any measures. Conclusions FQHCs and look-alikes demonstrated equal or better performance than private practice primary care physicians on select quality measures despite serving patients with more chronic disease and socioeconomic complexity. These findings can provide policymakers with some reassurance as to the quality of chronic disease and preventive care at Federally Qualified Health Centers and Federally Qualified Health Center look-alikes, as they plan to use these health centers to serve 20 million newly insured individuals.

Host-microbial interactions play a key role during the development of colitis. We have previously shown that chinase 3-like 1 (CHI3L1) is an inducible molecule overexpressed in colonic epithelial cells (CECs) under inflammatory conditions. In this study, we found that chitin-binding motif (CBM) of CHI3L1 is specifically associated with the CHI3L1-mediated activation of the Akt-signaling in CEC by transfecting the CBM-mutant CHI3L1 vectors in SW480 CECs. Downstream, CHI3L1 enhanced the secretion of IL-8 and TNFα in a dose-dependent manner. We previously show that 325 through 339 amino-acids in CBM are crucial for the biological function of CHI3L1. Here we demonstrated that 325th–339th residues of CBM in CHI3L1 is a critical region for the activation of Akt, IL-8 production, and for a specific cellular localization of CHI3L1. In conclusion, CBM region of CHI3L1 is critical in activating Akt signaling in CECs, and the activation may be associated with the development of chronic colitis.

BackgroundGeobacter species are δ-Proteobacteria and are often the predominant species in a variety of sedimentary environments where Fe(III) reduction is important. Their ability to remediate contaminated environments and produce electricity makes them attractive for further study. Cell motility, biofilm formation, and type IV pili all appear important for the growth of Geobacter in changing environments and for electricity production. Recent studies in other bacteria have demonstrated that signaling pathways homologous to the paradigm established for Escherichia coli chemotaxis can regulate type IV pili-dependent motility, the synthesis of flagella and type IV pili, the production of extracellular matrix material, and biofilm formation. The classification of these pathways by comparative genomics improves the ability to understand how Geobacter thrives in natural environments and better their use in microbial fuel cells.ResultsThe genomes of G. sulfurreducens, G. metallireducens, and G. uraniireducens contain multiple (~70) homologs of chemotaxis genes arranged in several major clusters (six, seven, and seven, respectively). Unlike the single gene cluster of E. coli, the Geobacter clusters are not all located near the flagellar genes. The probable functions of some Geobacter clusters are assignable by homology to known pathways; others appear to be unique to the Geobacter sp. and contain genes of unknown function. We identified large numbers of methyl-accepting chemotaxis protein (MCP) homologs that have diverse sensing domain architectures and generate a potential for sensing a great variety of environmental signals. We discuss mechanisms for class-specific segregation of the MCPs in the cell membrane, which serve to maintain pathway specificity and diminish crosstalk. Finally, the regulation of gene expression in Geobacter differs from E. coli. The sequences of predicted promoter elements suggest that the alternative sigma factors σ28 and σ54 play a role in regulating the Geobacter chemotaxis gene expression.ConclusionThe numerous chemoreceptors and chemotaxis-like gene clusters of Geobacter appear to be responsible for a diverse set of signaling functions in addition to chemotaxis, including gene regulation and biofilm formation, through functionally and spatially distinct signaling pathways.

Despite increasing reports that CCCH zinc finger proteins function in plant development and stress responses, the functions and molecular aspects of many CCCH zinc finger proteins remain uncharacterized. Here, we characterized the biological and molecular functions of AtC3H17, a unique Arabidopsis gene encoding a non-tandem CCCH zinc finger protein. AtC3H17 was ubiquitously expressed throughout the life cycle of Arabidopsis plants and their organs. The rate and ratio of seed germination of atc3h17 mutants were slightly slower and lower, respectively, than those of the wild type (WT), whereas AtC3H17-overexpressing transgenic plants (OXs) showed an enhanced germination rate. atc3h17 mutant seedlings were smaller and lighter than WT seedlings while AtC3H17 OX seedlings were larger and heavier. In regulation of flowering time, atc3h17 mutants showed delayed flowering, whereas AtC3H17 OXs showed early flowering compared with the WT. In addition, overexpression of AtC3H17 affected seed development, displaying abnormalities compared with the WT. AtC3H17 protein was localized to the nucleus and showed transcriptional activation activity in yeast and Arabidopsis protoplasts. The N-terminal region of AtC3H17, containing a conserved EELR-like motif, was necessary for transcriptional activation activity, and the two conserved glutamate residues in the EELR-like motif played an important role in transcriptional activation activity. Real-time PCR and transactivation analyses showed that AtC3H17 might be involved in seed development via transcriptional activation of OLEO1, OLEO2 and CRU3. Our results suggest that AtC3H17 has pleiotropic effects on vegetative development such as seed germination and seedling growth, flowering and seed development, and functions as a nuclear transcriptional activator in Arabidopsis.

AtNAP , an Arabidopsis NAC transcription factor family gene, functions as a negative regulator via transcriptional repression of AREB1 in salt stress response. AtNAP is an NAC family transcription factor in Arabidopsis and is known to be a positive regulator of senescence. However, its exact function and underlying molecular mechanism in stress responses are not well known. Here, we investigated functional roles of AtNAP in salt stress response. AtNAP expression significantly increased at the seedling stage, with higher expression in both shoots and roots under NaCl, mannitol, and ABA treatments. T-DNA insertional loss-of-function mutants of AtNAP were more tolerant to salt stress than wild type (WT), whereas AtNAP-overexpressing transgenic plants (OXs) were more sensitive to salt stress than WT during germination, seedling development, and mature plant stage. Transcript levels of stress-responsive genes in the ABA-dependent pathway, such as AREB1, RD20, and RD29B, were significantly higher and lower in atnap mutants and AtNAP OXs, respectively, than in WT under salt stress conditions, suggesting that AtNAP might negatively regulate the expression of those genes under salt stress conditions. Indeed, AtNAP repressed the promoter activity of AREB1 under normal and salt stress conditions. These results indicate that AtNAP functions as a negative regulator in the salt stress response. Our results, together with previous studies, suggest that AtNAP functions as a negative regulator in osmotic stress responses, whereas it functions as a positive regulator in senescence.

Background Chitinase 3-like 1 (CHI3L1) is an inducible molecule on intestinal epithelial cells (IECs) during the development inflammatory bowel disease (IBD). Methods To investigate the role of CHI3L1 in bacterial infectious colitis, we orally inoculated pathogenic Salmonella typhimurium and potentially pathogenic adherent-invasive Escherichia coli (AIEC) LF82 virulent strain, into C57Bl/6 wild-type (WT) or CHI3L1 knockout (KO) mice. Results Both S. typhimurium and AIEC LF82 were found to efficiently induce severe intestinal inflammation in WT but not CHI3L1 KO mice. These bacteria-infected CHI3L1 KO mice exhibit decreased cellular infiltration, bacterial translocation and productions of IL-6 and IL-22, as compared to those of WT mice. More importantly, CHI3L1 KO mice displayed aberrant STAT3 activation after bacterial infections. Co-stimulation of CHI3L1 and IL-6, but not IL-22, synergistically activates STAT3 signaling pathway in IECs in an NF-κB/MAPK dependent manner. Conclusions CHI3L1 promotes the onset of selected gram-negative bacterial infectious colitis through IL-6/STAT3 pathway.