Antifungal mechanism of antibacterial peptide, ABP-CM4, from Bombyx mori against Aspergillus niger.
Antibacterial peptide, CM4 (ABP-CM4), a 35 amino acid peptide from Chinese silkworm-Bombyx mori, displayed a strong antifungal activity against Aspergillus niger, Trichoderma viride and Gibberella saubinetii. Scanning electron microcopy showed that the morphology of conidia became more irregular and swelled when treated with ABP-CM4 at its minimal inhibitory concentration (MIC) of 8 muM. A cell wall regeneration assay indicated that the plasma membrane was the prime target of ABP-CM4 action. Confocal laser scanning microscopy showed that the cytoskeleton of A. niger was destroyed when treated with ABP-CM4 at 8 muM. Furthermore, transmission electron microscopy showed that the membrane and the cellular organelles of fungus were disrupted and there were many vacuoles in the fungal cellular space after the treatment with ABP-CM4. A gel-retardation assay showed that ABP-CM4 bound the DNA of A. niger. Our results suggest that ABP-CM4 exerts its antifungal activity by disrupting the structure of cell membranes and the cytoskeleton and interacts with the organelles, such as the mitochondrion and with the DNA in the fungal cell, subsequently resulting in cell death.
Zhang
Jie
J
Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210046, China.
Wu
Xi
X
Zhang
Shuang-Quan
SQ
D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D000935:Antifungal Agents / Q000378:metabolism / Q000494:pharmacology*; D001234:Aspergillus niger / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D012831:Bombyx / Q000737:chemistry*; D054807:Cecropins / Q000378:metabolism / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D004271:DNA, Fungal / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D015388:Organelles / Q000187:drug effects / Q000648:ultrastructure; D011523:Protoplasts / Q000187:drug effects / Q000502:physiology; D013172:Spores, Fungal / Q000502:physiology
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D054807:Cecropins; D004271:DNA, Fungal