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E. coli O157:H7 is the most common cause of hemorrhagic colitis, and no effective therapy exists for E. coli O 157:H7 infection. Biofilm formation is closely related to E. coli O157:H7 infection and constitutes a mechanism of antimicrobial resistance. Hence, the antibiofilm or antivirulence approach provides an alternative to antibiotic strategies. Coumarin and its derivatives have a broad range of biological effects, and in this study, the antibiofilm activities of nine coumarins were investigated against E. coli O157:H7. Coumarin or umbelliferone at 50 µg/ml was found to inhibit biofilm E. coli O157:H7 formation by more than 80% without affecting bacterial growth. Transcriptional analysis showed that coumarins repressed curli genes and motility genes in E. coli O157:H7, and these findings were in-line with observed reductions in fimbriae production, swarming motility, and biofilm formation. In addition, esculetin repressed Shigalike toxin gene stx2 in E. coli O157:H7 and attenuated its virulence in vivo in the nematode Caenorhabditis elegans. These findings show that coumarins have potential use in antivirulence strategies against persistent E. coli O157:H7 infection. Keywords: Biofilm formation Coumarin Escherichia coli O157:H7 Esculetin Umbelliferone Virulence, Introduction Shiga-like toxigenic E. coli O157:H7 has caused a large number of foodborne outbreaks worldwide. E. coli O157:H7 contamination on various surfaces causes approximately 73,000 infections annually in the U.S., [...]

Design rationales in the design process have attracted keen attention in recent years because they take into account the grounds and explanation behind a design decision, the other possibilities and tradeoffs considered and the rational debate that resulted in that decision. Design rationale systems capture and facilitate the access to design rationales. These systems are useful to design technology but most design rationale systems in existence today do not take into account practical matters such as cost-effective use.

The differential gene expression profile in biofilms for both the mutants (yliH and yceP) relative to the wild-type strain in rich medium with glucose were examined to determine the genetic basis of the increase in biofilm formation. The results revealed that the increase in biofilm formation was related to stress response for both yliH and yceP mutants.

A study was conducted to analyze a unique theoretical and empirical approach to tasks such as knowledge management and business process redesign. Examples on how different organizations carry out similar processes were examined and compiled in an on-line process handbook. The handbook was designed to aid people redesign their existing organizational procedures and develop novel organizational processes. It also allows individuals to share their respective ideas about organizational practices. Results indicated the effectiveness of the approach in representing similarities and differences among related processes and its ability to produce sensible options for how a given process could be carried out.