• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1183-1189
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• 2021

Autodisplay of a multimeric protein complex on a cell surface is limited by intrinsic factors such as the types and orientations of anchor modules. Moreover, improper folding of proteins to be displayed often hinders functional cell surface display. While overcoming these drawbacks, we ultimately extended the applicability of the autodisplay platform to the display of a protein complex. We designed and constructed a cell surface attachment (CSA) system that uses a non-covalent protein-protein interaction. We employed the high-affinity interaction mediated by an orthogonal cohesin-dockerin (Coh-Doc) pair from Archaeoglobus fulgidus to build the CSA system. Then, we validated the orthogonal Coh-Doc binding by attaching a monomeric red fluorescent protein to the cell surface. In addition, we evaluated the functional anchoring of proteins fused with the Doc module to the autodisplayed Coh module on the surface of Escherichia coli. The designed CSA system was applied to create a functional attachment of dimeric α-neoagarobiose hydrolase to the surface of E. coli cells.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.272-278
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• 2013

To evaluate the effect of surface contaminated with Escherichia coli O157:H7 (E. coli O157:H7) on the microbiological safety of lettuce, this study was conducted to investigate the attachment, biofilm producing, survival, and cross-contamination of E. coli O157:H7 on stainless steel and polyvinyl chloride (PVC). The attachment rate of E. coli O157:H7 on PVC was 10 times higher than that on stainless steel after exposure 1 h in cell suspension. However, there was not a difference between two types of surface after exposure for 6 h and 24h. The biofilm producing of E. coli O157:H7 was TSB > 10% lettuce extracts > 1% lettuce extracts > phosphate buffer. When two kinds of materials were stored at various conditions ($20^{\circ}C$ and $30^{\circ}C$, relative humidity (RH) 43%, 69%, and 100%), the numbers of E. coli O157:H7 at $30^{\circ}C$, RH 43% or RH 69% were reduced by 5.0 log CFU/coupon within 12 h regardless of material type. Conversely, the survival of E. coli O157:H7 at RH 100% was lasted more than 5 days. In addition, the reduction rate of E. coli O157:H7 was decreased in the presence of organic matter. The transfer efficiency of E. coli O157:H7 from the contaminated surface to lettuce was dependent upon the water amount of the surface of lettuce. Especially, the transfer rate of E. coli O157:H7 was increased by 10 times in the presence of water on the lettuce surface. From this study, the retention of E. coli O157:H7 on produce contact surfaces increase the risk cross-contamination of this pathogen to produce. Thus, it is important that the surface in post harvest facility is properly washed and sanitized after working for prevention of cross-contamination from surface.

• Journal of Periodontal and Implant Science
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• v.40 no.6
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• pp.257-264
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• 2010

Purpose: Connective tissue reattachment to periodontally damaged root surfaces is one of the most important goals of periodontal therapy. The aim of this study was to develop a root conditioning agent that can demineralize and detoxify the infected root surface. Methods: Dentin slices obtained from human teeth were treated with a novel root planing agent for 2 minutes and then washed with phosphate-buffered saline. Smear layer removal and type I collagen exposure were observed by scanning electron microscopy (SEM) and type I collagen immunostaining, respectively. Cell attachment and lipopolysaccharides (LPS) removal demonstrated the efficiency of the root conditioning agent. Results: SEM revealed that the smear layer was entirely removed and the dentinal tubules were opened by the experimental gel. Type I collagen was exposed on the surfaces of the dentin slices treated by the experimental gel, which were compared with dentin treated with other root planing agents. Dentin slices treated with the experimental gel showed the highest number of attached fibroblasts and flattened cell morphology. The agar diffusion assay demonstrated that the experimental gel also has effective antimicrobial activity. Escherichia coli LPS were effectively removed from well plates by the experimental gel. Conclusions: These results demonstrated that this experimental gel is a useful tool for root conditioning of infected root surfaces and can also be applied for detoxification of ailing implant surface threads.