Drosomycin is an inducible antifungal peptide of 44 residues initially isolated from bacteria-challenged Drosophila melanogaster. The systemic expression of drosomycin is regulated by the Toll pathway present in fat body, whereas inducible local expression in the respiratory tract is controlled by the Immune Deficiency (IMD) pathway. Drosomycin belongs to the cysteinestabilized a-helical and b-sheet (CSab) superfamily and is composed of an a-helix and a three-stranded bsheet stabilized by four disulphide bridges. Drosomycin exhibits a narrow antimicrobial spectrum and is only active against some filamentous fungi. However, recent work using recombinant drosomycin expressed in Escherichia coli revealed its antiparasitic and anti-yeast activities. Two evolutionary epitopes (a-and g-patch) and the m-loop have been proposed as putative functional regions of drosomycin for interaction with fungi and parasites, respectively. Similarity in sequence, structure and biological activity suggests that drosomycin and some defensin molecules from plants and fungi could originate from a common ancestor.

ABSTRACT. In this study, the phenotypic identification and molecular mechanism of one case of an A 2 B subtype pedigree was investigated. ABO blood groupings were identified by serological methods and sequence amplification was performed by polymerase chain reaction (PCR) using TA cloning and DNA sequencing analysis to identify the pedigree and the ABO gene haploid of the proband. There were both A and B antigens on the proband's red blood cells, and anti-A 1 antibodies were found in the serum. Direct sequencing of the 6th and 7th exons of the ABO gene showed the A208/B101 genotype, and haploid determination revealed the A208 and B101 alleles. Compared with the A102 allele sequence, the A208 allele was mutated at the 539 G>C site. Pedigree analysis showed that the ABO blood phenotypes of the proband's father, mother, husband, and daughter were A2, B, AB, and A 2 B, respectively, and their genotypes were A208/O02, B101/ B101, A102/B101, and A208/B101, respectively. The father of the proband had anti-A 1 antibodies and the A208 allele of the proband was inherited from her father, which can be passed on to her daughter. The α-1, 3-N-acetylgalactose aminotransferase gene 539G>C mutation