The present study reports a new type of skin mucus lectin found in catfish Silurus asotus. The lectin exhibited calcium-dependent mannose-binding activity. When mannose eluate from chromatography with mannose-conjugated agarose was analysed by SDS-PAGE, the lectin appeared as a single 35-kDa band. Gel filtration showed that the lectin forms monomers and dimers. A 1216-bp cDNA sequence obtained by RACE-PCR from the skin encoded a 308 amino acid secretory protein with homology to mammalian and fish intelectins. RT-PCR demonstrated that the lectin gene was expressed in the gill, kidney and skin. Subsequent sequencing revealed the presence of an isoform in the gills. Antiserum detected the intelectin protein in club cells in the skin and gill, renal tubules and blood plasma. Although intelectin gene expression was not induced by in vivo bacterial stimulation, the intelectin showed agglutination activity against the pathogenic bacterium Aeromonas salmonicida, suggesting that the lectin plays an important role in self-defence against bacteria in the skin surface of the catfish. These findings represent one of the few examples of characterization and functional analysis of a fish intelectin protein.

The piezoresistive effect is characterized by the change in the resistivity of a material relative to mechanical forces exerted on it. Such materials can be used as pressure sensors and are among the most important components for micro-electro mechanical system applications. To date, most research on the piezoresistive effect has been directed toward cubic crystalline materials such as Si; however, the prospective non-cubic materials, such as SiC, are known to have exciting and promising properties. SiC exhibits high-temperature robustness and is chemically stable. It is expected that these properties can be applied to a variety of applications. These materials fall in the category of hexagonal crystalline systems, and it is difficult to evaluate the piezoresistive properties of such materials. In this study, we discuss the piezoresistive mobility model that corresponds to both the cubic and the hexagonal crystalline systems. This mobility model is derived from the empirical fitting of the Gauge Factor (GF) values using the longitudinal and the transverse piezoresistive coefficients and the material-unique fitting parameters. Our proposed method has been implemented in the original device simulator and has been evaluated with respect to both Si and SiC materials. This report shows the well-matched GF values and suggests that the proposed piezoresistive effect model can be implemented in device simulation modeling.

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