Bacterial Agglutination by Sialic Acid-Specific Lectin in the Hemolymph of the Banana Shrimp, Penaeus (Fenneropenaeus) merguiensis

Prapaporn Utarabhand*, Wanida Rittidach and Nisa Paijit

ABSTRACT: A lectin from the hemolymph of the banana shrimp Penaeus (Fenneropenaeus) merguiensis expressed higher agglutination activity against rabbit erythrocytes than those from human, and its activity was Ca²⁺- dependent. The hemagglutinating activity of the hemolymph lectin was stable up to 55 oC and optimal at pH 7.5-8.0. N-acetylated sugars, ManNAc, GlcNAc, GalNAc, and NeuNAc, were effective inhibitors of the lectin induced hemagglutinating activity, with NeuNAc being the most powerful. Porcine stomach mucin and fetuin showed high inhibitory activity to the hemolymph lectin-induced hemagglutination. In addition, the hemolymph lectin selectively agglutinated Vibrio harveyi and V. parahemolyticus, which are pathogenic to P. merguiensis, and to a lesser extent, V. vulnificus, but had no effect on the non-pathogenic V. cholerae, Samonella typhi and Escherichia coli. This observation suggests that lectin present in the hemolymph of P. merguiensis may contribute to the defense mechanism of this species against bacterial infections.

KEYWORDS: lectin, crustacean, Penaeus (Fenneropenaeus) merguiensis, banana shrimp, hemolymph.

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Department of Biochemistry, Faculty of Science, Prince of Songkhla University, Hat Yai, Songkla 90112, Thailand.

* Corresponding author, E-mail: uprapa1@yahoo.com

Received 29 May 2006, Accepted 18 Aug 2006