Biology subjects

Kapczynska, K.

Publications and source records attributed to Kapczynska, K..

3 recordsLinked to original sources

bioRxiv2025

Establishing Essential Oil Stewardship Through the Case of Rosemary and Thyme Oils Against Staphylococcus aureus

Essential oils (EOs) have long been studied for their antimicrobial properties, yet most investigations rely on simplistic models, limited strain panels, and anecdotal interpretations - failing to meet the standards expected of modern anti-infective agents. Advancing beyond this tradition, we implement a framework developed over several years of systematic investigation. Using this approach, we assessed the antibiofilm activity of Rosmarinus officinalis L. and Thymus vulgaris L. EOs against a panel of clinical Staphylococcus aureus isolates obtained from non-healing wounds. By applying infection-relevant conditions, such as wound-mimicking media and surfaces, strain-level resolution, and both contact and volatile exposure, we revealed substantial inter-strain variability in susceptibility, challenging the notion of EOs as uniformly effective agents. This variability was quantified using robust statistics, lending confidence to the reproducibility and translational relevance of the findings. These results underscore the need for Essential Oil Stewardship: a reproducible, interdisciplinary framework for EO testing, interpretation, and clinical translation. Our work demonstrates that such approach is feasible and sets the foundation for its broader adoption. The key message from this study is that EOs cannot meaningfully support or complement antibiotics and antiseptic agents in combating infections unless they are evaluated with the same methodological rigor.

microbiology↗

bioRxiv2025

Toward Essential Oil Stewardship Strain-Resolved Evaluation of Thyme Oil Activity Against Pseudomonas aeruginosa

AbstractThe rising interest in essential oils (EOs) as antimicrobial agents demands evaluation frameworks that move beyond anecdotal efficacy and toward structured, reproducible assessment. In this study, we examined the strain-dependent response of Pseudomonas aeruginosa to Pharmacopoeia-grade Thyme Essential Oil (TEO) or polyhexamethylene biguanide antiseptic (PHMB), using a panel of ten genetically diversified strains in planktonic and biofilm form and by complementary in vitro models. Despite uniform test conditions, we observed striking inter-strain variability: TEO Minimal Inhibitory Concentrations (MICs) differed by up to 1000-fold, and biofilm susceptibility profiles ranged from full tolerance to near-complete eradication. Notably, strains with low metabolic activity and sparse cell populations--but high matrix biomass--exhibited reduced responsiveness to TEO, while susceptibility to PHMB was more consistent, though not absolute. These findings highlight the critical influence of both microbial phenotype and agent formulation on antimicrobial outcomes. Rather than framing EOs as superior or inferior alternatives, our results advocate for their integration into a stewardship paradigm--one that values standardization, model-based evaluation, and informed formulation. In this context, we position essential oil stewardship not as a constraint, but as a necessary evolution for their credible inclusion in antimicrobial strategies.

microbiology↗

bioRxiv2021

Missing the sweet spot: one of the two N-glycans on human Gb3/CD77 synthase curtails its activity

N-glycosylation is a ubiquitous posttranslational modification that may influence folding, subcellular localization, secretion, solubility and oligomerization of proteins. In this study, we examined the effects of N-glycans on the activity of human Gb3/CD77 synthase, which catalyzes the synthesis of glycosphingolipids with terminal Gal1[->]4Gal (Gb3 and the P1 antigen) and Gal1[->]4GalNAc disaccharides (the NOR antigen). The human Gb3/CD77 synthase contains two occupied N-glycosylation sites at positions N121 and N203. Intriguingly, we found that while the N-glycan at N203 is essential for activity and correct subcellular localization, the N-glycan at N121 is dispensable and its absence did not reduce, but, surprisingly, even increased the activity of the enzyme. The fully N-glycosylated human Gb3/CD77 synthase and its glycoform missing the N121 glycan correctly localized in the Golgi, whereas a glycoform without the N203 site partially mislocalized in the endoplasmic reticulum. A double mutein missing both N-glycans was inactive and accumulated in the endoplasmic reticulum. Our results suggest that the decreased specific activity of human Gb3/CD77 synthase glycovariants results from their improper subcellular localization and, to a smaller degree, a decrease in enzyme solubility. Taken together, our findings show that the two N-glycans of human Gb3/CD77 synthase have opposing effects on its properties, revealing a dual nature of N-glycosylation and potentially a novel regulatory mechanism controlling the biological activity of proteins.

biochemistry↗