Study On The Mechanism Of Antifungal Peptide MAF-1A Against Candida Parapsilosis

Objective: To understand the antifungal peptide MAF-1A against Candida parapsilosis in vitro,its effect on the transcription level of Candida parapsilosis,and the antifungal activity of Candida parapsilosis biofilm.The research on MAF-1A antifungal action mechanism provides direction and lays the research foundation,and provides theoretical foundation and scientific basis for subsequent screening of efficient and safe new antifungal agents.Methods: 1.The antifungal peptide MAF-1A was obtained by FMOC solid-phase synthesis.The broth dilution antifungal susceptibility testing and colonies count method was used to detect the anti Candida parapsilosis activity of MAF-1A in vitro.2.Composing the Time-kill curves by liquid microdilution method and plate colonies counting method.3.Using RNA-seq sequencing analysis technology to study the transcription response of Candida parapsilosis under the action of antifungal peptide MAF-1A,providing research directions for studying the antifungal mechanism of MAF-1A,and enriching the data of Candida parapsilosis transcriptome database.4.In vitro biofilm modeling,absorbance detection,fluorescent labeling and other techniques were used to observe the effects of MAF-1A on the biofilm formation and cell activity of Candida parapsilosis,providing resources for the development of anti-biofilm infection agents.Results: 1.The antifungal activity of MAF-1A against Candida parapsilosis was different in different media.As the SDB dilution times increased,the antifungal activity of the peptide increased.2.MAF-1A showed obvious antifungal activity against Candida parapsilosis.Under the condition of 1/4SDB medium,the MIC of MAF-1A was 0.3mg/m L and MFC was 0.5mg/m L.The Time-kill curves showed that MAF-1A exerted antifungal effect gradually from 0h to 8h on Candida parapsilosis.3.Transcriptomics analysis of Candida parapsilosis.with antifungal peptide MAF-1A using RNA-seq technology,the results showed that in the early phase of peptideaction(6h),a total of 1,122 differentially up-regulated and 1065 down-regulated genes were detected.In the late stage(18h),101 genes were up-regulated and 151 genes were down-regulated.Among these differential genes,genes encoding genes related to ergosterol metabolism Significantly down-regulated,and genes associated with oxidative phosphorylation were significantly up-regulated.KEGG enrichment analysis showed that the differentially expressed genes caused by MAF-1A mainly involved processes such as amino acid synthesis and metabolism,oxidative phosphorylation,sterol synthesis,and apoptosis.4.MAF-1A can inhibit the formation of Candida parapsilosis biofilm,the polypeptide can bind and aggregate in the Candida parapsilosis biofilm,and significantly reduce the cell viability in the Candida parapsilosis biofilm.Conclusions: 1.MAF-1A has anti Candida parapsilosis,and its antifungal activity is affected by some environmental factors.2.The results of transcriptome studies indicate that MAF-1A may have multiple targets in Candida parapsilosis.It may inhibit the growth of Candida parapsilosis by affecting the normal function of multiple targets of the cell.MAF-1A may exert anti-fungal activity by destroying the cell membrane of Candida parapsilosis,affecting the normal exercise of functions such as inner ribosomes and mitochondria.3.MAF-1A has a significant inhibitory effect on Candida parapsilosis biofilm,and has important research significance in the development of anti-biofilm infection agents.