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Knoedlseder, N.

Publications and source records attributed to Knoedlseder, N..

3 recordsLinked to original sources

Genome editing of phylogenetically distinct bacteria using portable retron-mediated recombineering

Advanced genome editing technologies have enabled rapid and flexible rewriting of the Escherichia coli genome, benefiting fundamental biology and biomanufacturing. Unfortunately, some of the most useful technologies to advance genome editing in E. coli have not yet been ported into other bacterial species. For instance, the addition of bacterial retrons to the genome editing toolbox has increased the efficiency of recombineering in E. coli by enabling sustained, abundant production of ssDNA recombineering donors by reverse transcription that install flexible, precise edits in the prokaryotic chromosome. To extend the utility of this technology beyond E. coli, we surveyed the portability and versatility of retron-mediated recombineering across three different bacterial phyla (Proteobacteria, Bacillota and Actinomycetota) and a total of 15 different species. We found that retron recombineering is functional in all species tested, reaching editing efficiencies above 20% in six of them, above 40% in three of them, and above 90% in two of them. We also tested the extension of the recombitron architecture optimizations and strain backgrounds in a subset of hosts to additionally increase editing rates. The broad recombitron survey carried out in this study forms the basis for widespread use of retron-derived technologies through the whole Bacteria domain.

bioengineering↗

New insights into the role of Cutibacterium acnes-derived extracellular vesicles in inflammatory skin disorders

BackgroundCutibacterium acnes (C. acnes) is one of the most prevalent bacteria that form the human skin microbiota and, depending on multifactorial conditions it can help to maintain the skin homeostasis. Actually, different phylotypes of C. acnes have been associated with different degrees of acne vulgaris development, while others, such as the H1 subtype, have been detected in patients with non-acneic skin. However, due to the physiology of the skin, the skin microbiota neither has direct access to the skins sebaceous glands nor to the main immune cells, as they are protected by a sebum layer. Therefore, the inter-kingdom communication relies on secreted factors and bacterial extracellular vesicles (EVs). In this context, the purpose of this project was to study the role of EVs secreted by three different phylotypes of C. acnes (A1 as pathogenic, H1 as beneficial and H2 as commensal). ResultsMain findings showed that the proteomic profile of the cargo embodied in the EVs reflects unique characteristics of the different C. acnes phylotypes in terms of lifestyle, survival and virulence. Moreover, in vitro skin models showed an extended pro-inflammatory modulation of A1 EVs, while H1 EVs displayed a high sebum-reducing potential. ConclusionsThis study has highlighted the role of C. acnes EVs as key modulators during skin alterations, specially H1 EVs as an alternative based-natural treatment to fight acne vulgaris symptomatology.

immunology↗

Engineering selectivity of Cutibacterium acnes phages by epigenetic imprinting

Cutibacterium acnes (C. acnes) is a gram-positive bacterium and a member of the human skin microbiome. Despite being the most abundant skin commensal, certain members have been associated with common inflammatory disorders such as acne vulgaris. The availability of the complete genome sequences from various C. acnes clades have enabled the identification of putative methyltransferases, some of them potentially belonging to restriction-modification (R-M) systems which protect the host of invading DNA. However, little is known on whether these systems are functional in the different C. acnes strains. To investigate the activity of these putative R-M and their relevance in host protective mechanisms, we analyzed the methylome of seven representative C. acnes strains by Oxford Nanopore Technologies (ONT) sequencing. We detected the presence of a 6-methyladenine modification at a defined DNA consensus sequence in strain KPA171202 and recombinant expression of this R-M system confirmed its methylation activity. Additionally, a R-M knockout mutant verified the loss of methylation properties of the strain. We studied the potential of one C. acnes bacteriophage (PAD20) in killing various C. acnes strains and linked an increase in its specificity to phage DNA methylation acquired upon infection of a methylation competent strain. We demonstrate a therapeutic application of this mechanism where phages propagated in R-M deficient strains selectively kill R-M deficient acne-prone clades while probiotic ones remain resistant to phage infection. Graphical abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

microbiology↗