title: A dual mechanism involved in membrane and nucleic acid disruption of AvBD103b, a new avian defensin from the king penguin, against Salmonella enteritidis CVCC3377.
abstract: The food-borne bacterial gastrointestinal infection is a serious public health threat. Defensins are evolutionarily conserved innate immune components with broad-spectrum antibacterial activity that do not easily induce resistance. AvBD103b, an avian defensin with potent activity against Salmonella enteritidis, was isolated from the stomach contents of the king penguin (Aptenodytes patagonicus). To elucidate further the antibacterial mechanism of AvBD103b, its effect on the S. enteritidis CVCC3377 cell membrane and intracellular DNA was researched. The cell surface hydrophobicity and a N-phenyl-1-naphthylamine uptake assay demonstrated that AvBD103b treatment increased the cell surface hydrophobicity and outer membrane permeability. Atomic absorption spectrometry, ultraviolet spectrophotometry, flow cytometry, and transmission electron microscopy (TEM) indicated that AvBD103b treatment can lead to the release of the cellular contents and cell death through damage of the membrane. DNA gel retardation and circular dichroism analysis demonstrated that AvBD103b interacted with DNA and intercalated into the DNA base pairs. A cell cycle assay demonstrated that AvBD103b affected cellular functions, such as DNA synthesis. Our results confirmed that AvBD103b exerts its antibacterial activity by damaging the cell membrane and interfering with intracellular DNA, ultimately causing cell death, and suggested that AvBD103b may be a promising candidate as an alternative to antibiotics against S. enteritidis.
authors: Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Beijing, 100081, People's Republic of China.
authors: Da
authors: D
authors: Teng
authors: Xiumin
authors: X
authors: Wang
authors: Di
authors: D
authors: Xi
authors: Ruoyu
authors: R
authors: Mao
authors: Yong
authors: Y
authors: Zhang
authors: Qingfeng
authors: Q
authors: Guan
authors: Jun
authors: J
authors: Zhang
authors: Jianhua
authors: J
authors: Wang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D030161:Avian Proteins / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects*; D002463:Cell Membrane Permeability / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D023082:Defensins / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects; D006460:Hemolysin Proteins / Q000494:pharmacology; D006801:Humans; D012477:Salmonella enteritidis / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics*; D046429:Spheniscidae / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D030161:Avian Proteins; D023082:Defensins; D006460:Hemolysin Proteins