iTRAQ-based quantitative proteomics analysis reveals inhibitory mechanismsof the antimicrobial peptide MDAP-2 against
1College of Animal Science and Technology, Jilin Agricultural University, Xincheng Street No. 2888, Changchun 130118, PR China.
Abstract:
MDAP-2 is a new AMP with high inhibitory activity on Salmonella gallinarum, which may be developed as an antimicrobial agent in the agricultural industry and food preservation. To investigate the underlying the action mechanism of MDAP-2 on Salmonella gallinarum, impacts of MDAP-2 on the growth curve and bacterial morphology of Salmonella gallinarum were studied. iTRAQ-based proteomics analysis was also performed on proteins extracted from treated and untreated Salmonella gallinarum cells. The differentially expressed proteins were then analyzed using the KEGG and GO databases. Finally, the function of some differentially expressed proteins was verified. The results showed that 150 proteins (41 up-regulated and 109 down-regulated) were found differentially expressed (fold > 1.8, p⟨0.05). The results indi- cate that MDAP-2 kills Salmonella gallinarum mainly through two mechanisms: (i) direct inhibi- tion of cell wall/ membrane/ envelope biogenesis, energy production/ conversion, carbohydrate transport/ metabolism, and DNA transcription/ translation through regulation of special protein levels; (ii) indirect effects on the same pathway through the accumulation of Reactive oxygen species (O2 ▪-, H2O2 and OH▪-).
Insights
MDAP-2, a novel antimicrobial peptide, effectively inhibits Salmonella gallinarum by disrupting essential bacterial processes like cell wall synthesis and energy production. This peptide also induces reactive oxygen species, offering potential for agricultural and food preservation applications.
Area of Science:
- Microbiology
- Biochemistry
- Proteomics
Background:
- Salmonella gallinarum poses a significant threat to animal health and food safety.
- Antimicrobial peptides (AMPs) are a promising alternative to conventional antibiotics.
- MDAP-2 is a newly identified AMP with potent activity against Salmonella gallinarum.
Purpose of the Study:
- To elucidate the molecular mechanisms by which MDAP-2 exerts its antimicrobial effects on Salmonella gallinarum.
- To investigate the impact of MDAP-2 on bacterial growth, morphology, and protein expression.
Main Methods:
- Growth curve analysis and electron microscopy to assess morphological changes.
- iTRAQ-based quantitative proteomics to identify differentially expressed proteins.
- Bioinformatic analysis using KEGG and GO databases for pathway enrichment.
- Functional validation of key differentially expressed proteins.
Main Results:
- MDAP-2 significantly altered the growth curve and morphology of Salmonella gallinarum.
- Proteomic analysis identified 150 differentially expressed proteins (41 up-regulated, 109 down-regulated) upon MDAP-2 treatment.
- Key pathways affected include cell wall/membrane biogenesis, energy metabolism, carbohydrate transport, and DNA transcription/translation.
- MDAP-2 treatment led to the accumulation of reactive oxygen species (ROS) in Salmonella gallinarum.
Conclusions:
- MDAP-2 exhibits antimicrobial activity against Salmonella gallinarum through dual mechanisms: direct inhibition of vital cellular processes and induction of oxidative stress via ROS accumulation.
- The findings support the potential development of MDAP-2 as a novel antimicrobial agent for agricultural and food preservation applications.
