In recent years, there has been considerable interest in lectins from marine invertebrates. In this study, the biological activities of a lectin protein isolated from the eggs of Sea hare (Aplysia kurodai) were evaluated. The 40 kDa Aplysia kurodai egg lectin (or AKL-40) binds to D-galacturonic acid and D-galactose sugars similar to previously purified isotypes with various molecular weights (32/30 and 16 kDa). The N-terminal sequence of AKL-40 was similar to other sea hare egg lectins. The lectin was shown to be moderately toxic to brine shrimp nauplii, with an LC50 value of 63.63 µg/mL. It agglutinated Ehrlich ascites carcinoma cells and reduced their growth, up to 58.3% in vivo when injected into Swiss albino mice at a rate of 2 mg/kg/day. The morphology of these cells apparently changed due to AKL-40, while the expression of apoptosis-related genes (p53, Bax, and Bcl-XL) suggested a possible apoptotic pathway of cell death. AKL-40 also inhibited the growth of human erythroleukemia cells, probably via activating the MAPK/ERK pathway, but did not affect human B-lymphoma cells (Raji) or rat basophilic leukemia cells (RBL-1). In vitro, lectin suppressed the growth of Ehrlich ascites carcinoma and U937 cells by 37.9% and 31.8%, respectively. Along with strong antifungal activity against Talaromyces verruculosus, AKL showed antibacterial activity against Staphylococcus aureus, Shigella sonnei, and Bacillus cereus whereas the growth of Escherichia coli was not affected by the lectin. This study explores the antiproliferative and antimicrobial potentials of AKL as well as its involvement in embryo defense of sea hare.

Influences of vapors evaporated from an acryl-based non-silicone-type polymeric cured material and conventional silicone-containing polymeric cured materials were evaluated with respect to their effects on contact resistance characteristics of relay contacts at an ambient temperature of 120ºC. More specifically, a commercially-available mechanical relay (AgSnIn contacts) was sealed into a metal can with one of these materials, and placed in a heating chamber to operate, at an operating frequency of 0.5 Hz, 40,000 break operations of an inductive DC 14V-1A, 14V-0.4A, 10V-1A, 5V-1A load currents, or a resistive DC 14V-1A load current. Contact resistance values were measured at every 50 operations. As a result, the relays sealed with the acryl-based non-silicone-type polymeric cured material showed no deterioration in contact resistances, irrespective of the load conditions. On the other hand, the relays sealed with the silicone-containing polymeric cured materials showed more significant deteriorations and fluctuations of the contact resistance characteristics, and certain influences of load conditions on their behaviors were recognized.

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