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bioRxiv · 10.1101/2023.03.02.530746

Antimicrobial peptides originating from expression libraries of Aurelia aurita and Mnemiopsis leidyi prevent biofilm formation of opportunistic pathogens

Ladewig, L.·Gloy, L.·Langfeldt, D.·Pinnow, N.·Weiland-Braeuer, N.·Schmitz, R. A.
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Abstract

The demand for novel antimicrobial compounds is rapidly growing due to the rising appearance of antibiotic resistance in bacteria; accordingly, alternative approaches are urgently needed. Antimicrobial peptides (AMPs) are promising since they are a naturally occurring part of the innate immune system and display remarkable broad-spectrum activity and high selectivity against various microbes. Marine invertebrates are a primary resource of natural AMPs. Consequently, cDNA expression (EST) libraries from the Cnidarian moon jellyfish Aurelia aurita and the Ctenophore comb jelly Mnemiopsis leidyi were constructed in Escherichia coli. Cell-free size-fractionated cell extracts (< 3 kDa) of the two libraries (each with 29,952 clones) were consecutively screened for peptides preventing the biofilm formation of opportunistic pathogens using the crystal violet assay. The 3 kDa fraction of ten individual clones demonstrated promising biofilm-preventing activities against Klebsiella oxytoca and Staphylococcus epidermidis. Sequencing the respective activity-conferring inserts allowed the identification of small ORFs encoding peptides (10 - 22 aa), which were subsequently chemically synthesized to validate their inhibitory potential. Biofilm-preventing effects against K. oxytoca, Pseudomonas aeruginosa, S. epidermidis, and S. aureus were verified for five synthetic peptides in a concentration-dependent manner, with peptide BiP_Aa_5 showing the strongest effects. The impact of BiP_Aa_2, BiP_Aa_5, and BiP_Aa_6 on dynamic biofilm formation of K. oxytoca was further validated in microfluidic flow cells, demonstrating a significant reduction in biofilm thickness and volume by BiP_Aa_2 and BiP_Aa_5. Overall, the structural characteristics of the marine invertebrate-derived AMPs, their physicochemical properties, and promising anti-biofilm effects highlight them as attractive candidates for discovering new antimicrobials.

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Ladewig, L., Gloy, L., Langfeldt, D., Pinnow, N., Weiland-Braeuer, N., Schmitz, R. A.. 2023-03-02. Antimicrobial peptides originating from expression libraries of Aurelia aurita and Mnemiopsis leidyi prevent biofilm formation of opportunistic pathogens. https://doi.org/10.1101/2023.03.02.530746

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