Study of biological activity and targeted distribution of catesbeianalectin in mouse tissue.

Lectin has attracted attention because of its ability to serve as a carrier for targeted drug delivery. Large lectins isolated from marine invertebrates and crustaceans have strong immunogenicity and adverse effects, which limit their usefulness. This study reports the identification of catesbeianalectin via screening a bullfrog skin cDNA library. The catesbeianalectin polypeptide has a molecular weight of 1.47 kD, making it the smallest known lectin in terms of molecular weight. Circular dichroism analysis showed a PPII helix secondary structure. Catesbeianalectin strongly induces agglutination of rabbit erythrocytes and a variety of pathogens include Staphylococcus aureus, Streptococcus suis type 2, Actinobacillus pleuropneumoniae, and piglet paratyphoid Salmonella. The mean serum titer in catesbeianalectin-immunized Balb/c mice was 1:25, which was significantly lower than that of positive controls immunized with wheat germ agglutinin. Surface plasmon resonance indicated an S-type lectin. 125I-labeled catesbeianalectin did not pass the blood-brain barrier. This study provides a basis for further research on the potential of catesbeianalectin as a carrier in targeted drug delivery.

[Cloning and sequencing of the gp23 gene encoding a surface antigen on sporozoites of Cryptosporidium parvum].

OBJECTIVE: To clone and sequence the gp23 gene encoding a surface antigen on the sporozoites of Cryptosporidium parvum. METHODS: Genomic DNA was isolated from oocysts of Cryptosporidium parvum. The gp23 gene was amplified by polymerase chain reaction (PCR) and cloned into pMD18-T vector and sequenced by the methods of dideoxy-mediated chain termination. RESULTS AND CONCLUSION: The gp23 gene was 345 bp in length and included an open reading frame encoding a protein of 114 amino acid residues. The homology of the nucleotide and amino sequences of the gp23 gene was 97.3% and 98.2% to that in the GenBank, respectively. The gp23 gene cloned contained 6 nucleotides more than that in the GenBank.