Inhibitory effect and possible mechanism of phenyllactic acid on Aspergillus flavus spore germination
Minghua Li1, Binbin Yao1, Xiumei Meng2
1School of Pharmacy, Jiangsu Food and Pharmaceutical Science College, Huai'an, Jiangsu, China.
Abstract:
Phenyllactic acid (PLA) has gained a lot of attention due to its broad antimicrobial activity, but the mechanism of its antifungal action has been barely reported until now. Herein, the inhibitory activity of PLA against Aspergillus flavus spore germination and its mechanism were preliminarily investigated. Results indicated that PLA had a strong antifungal activity against A. flavus with the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of 6 and 12 mg/ml, respectively. As observed by scanning electron microscopy (SEM), the A. flavus spores displayed wrinkled and shrunken appearance after treatment with PLA. In addition, the permeability and integrity of A. flavus cell membrane were changed obviously after PLA treatment as indicated by the propidium iodide (PI) staining results, which was further confirmed by a rise in electric conductivity and increased leakage of intracellular protein and nucleic acid. Furthermore, reduced activities of mitochondrial ATPase and dehydrogenases caused by PLA were also observed in A. flavus spores, with a result of remarkable decrease in ATP synthesis. Therefore, it could be concluded that PLA was effective in inhibiting spore germination of A. flavus mainly by disrupting cell membrane and interfering with mitochondrial energy metabolism.
Insights
Phenyllactic acid (PLA) effectively inhibits Aspergillus flavus spore germination by damaging the cell membrane and disrupting mitochondrial energy production. This study elucidates the antifungal mechanism of PLA against this common mold.
Area of Science:
- Microbiology
- Mycology
- Biochemistry
Background:
- Phenyllactic acid (PLA) exhibits broad antimicrobial properties, yet its antifungal mechanisms remain largely unexplored.
- Aspergillus flavus poses significant risks, necessitating effective control strategies.
Purpose of the Study:
- To investigate the antifungal activity of PLA against Aspergillus flavus spore germination.
- To elucidate the underlying mechanisms of PLA's antifungal action.
Main Methods:
- Minimal Inhibitory Concentration (MIC) and Minimal Fungicidal Concentration (MFC) determination.
- Scanning Electron Microscopy (SEM) for morphological changes.
- Propidium Iodide (PI) staining, electrical conductivity, and intracellular component leakage assays to assess cell membrane integrity.
- Enzyme activity assays (mitochondrial ATPase, dehydrogenases) and ATP synthesis measurement.
Main Results:
- PLA demonstrated potent antifungal activity with MIC of 6 mg/ml and MFC of 12 mg/ml against A. flavus.
- SEM revealed morphological damage, including wrinkled and shrunken spores, upon PLA treatment.
- PLA treatment compromised cell membrane integrity, evidenced by PI staining, increased electrical conductivity, and elevated leakage of intracellular proteins and nucleic acids.
- PLA significantly reduced mitochondrial ATPase and dehydrogenase activities, leading to decreased ATP synthesis in A. flavus spores.
Conclusions:
- Phenyllactic acid effectively inhibits Aspergillus flavus spore germination.
- PLA's antifungal mechanism involves disruption of the cell membrane and interference with mitochondrial energy metabolism.
Related Concept Videos
01:28Fungal Phylum Ascomycota
01:18Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex,...
01:28Antimicrobial Effectiveness