Antimicrobial activity spectrum, cDNA cloning, and mRNA expression of a newly isolated member of the cecropin family from the mosquito vector Aedes aegypti.
An antimicrobial peptide belonging to the cecropin family was isolated from the hemolymph of bacteria-challenged adult Aedes aegypti. This new peptide, named cecropin A, was purified to homogeneity and fully characterized after cDNA cloning. The 34-residue A. aegypti cecropin A is different from the majority of reported insect cecropins in that it is devoid of a tryptophan residue and C-terminal amidation. The importance of these two structural features on the activity spectrum was investigated using a chemically synthesized peptide. A comparison of the antimicrobial activity spectrum of A. aegypti and Drosophila cecropin A showed a lower activity for the mosquito molecule. A. aegypti cecropin mRNA expression was not detected by Northern blot or reverse transcription-polymerase chain reaction analysis in any immature stage of the mosquito, nor in naïve adults, but it was observed in challenged adults 6 h after bacteria inoculation, and it continued over 7-10 days.
Lowenberger
C
C
Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA.
Charlet
M
M
Vizioli
J
J
Kamal
S
S
Richman
A
A
Christensen
B M
BM
Bulet
P
P
D000330:Aedes / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006458:Hemolymph / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D010455:Peptides; D012333:RNA, Messenger; C031161:cecropin A