Search bioRxiv⌕ Search

Biology subjects

Ladewig, L.

Publications and source records attributed to Ladewig, L..

2 recordsLinked to original sources

Exploring new Bacteroidota strains: Functional Diversity and Probiotic Characteristics

Bacteroidota, a diverse phylum of bacteria, are increasingly recognized for their significant contributions to host health, particularly through their antimicrobial and probiotic properties. This study investigates the functional diversity and probiotic potential of 42 new Bacteroidota strains enriched and identified from diverse hosts, including mouse ceca and human stool samples. Using 16S rRNA gene sequencing, we phylogenetically characterized the strains of the genera Bacteroides, Phocaeicola and Sphingobacterium and assessed their functional properties related to probiotic potential. The strains were evaluated concerning their ability to inhibit biofilm formation of WHO declared clinically significant pathogens, including gram-positive Staphylococcus aureus and Staphylococcus epidermidis, gram-negative Klebsiella oxytoca and Pseudomonas aeruginosa, and the eukaryotic fungus Candida albicans. Additionally, we investigated bile salt hydrolase and quorum quenching activities of the strains, key traits associated with probiotic efficacy. Our findings demonstrate that all examined Bacteroidota strains consistently exhibit a capacity to inhibit biofilm formation but to different extent. Furthermore, 14 strains showed quorum quenching activity, and 39 bile salt hydrolase activity, highlighting their probiotic potential. High biofilm inhibition as well as quorum quenching activity against both autoinducers, AHL and AI-2, were predominantly observed in Bacteroides caecimuris and Bacteroides muris, making them attractive candidates for next-generation probiotics. Overall, this study advances the field of next-generation probiotics by identifying promising candidates for therapeutic applications potentially revolutionizing approaches to microbiome-based interventions and pathogen control in clinical settings.

microbiology↗

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

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.

microbiology↗