O'Connor, P. | Search bioRxiv

bioRxiv2026

Putative Herbicolin A, an antifungal lipopeptide produced by Pantoea agglomerans APC 4211 is a promising biocontrol agent against food spoilage fungi

Fungal contamination of food with yeast and moulds is associated with major economic losses due to spoilage and also poses health risks in the form of mycotoxin production. The strain Pantoea agglomerans APC 4211 isolated from leaves of Ilex aquifolium (holly tree) has broad spectrum antifungal activity against a variety of food spoilage fungi. Genomic analysis of the strain confirmed the presence of biosynthetic gene clusters potentially encoding for the enzymatic machinery required for the production of the antifungal lipopeptide herbicolin A. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of the cell-free supernatant (CFS) confirmed the presence of molecular masses corresponding to herbicolin A (1300.8 Da), and herbicolin B (1138 Da). Purified herbicolin A has desirable properties for biotechnological applications, including potent antifungal activity against a range of spoilage fungi, thermal stability and resistance to proteases. Herbicolin A has low cytotoxicity against epithelial cell lines and has minimum inhibitory concentrations (MICs) lower than those of some commercial antifungal drugs (0.2 - 2.5 {micro}g/ml). In a model dairy system (10% skim milk), herbicolin A demonstrated excellent solubility and stability, effectively eliminating Aspergillus niger and Penicillium notatum at a concentration of 5 {micro}g/mL. In conclusion, herbicolin A is a potent, naturally occurring antifungal agent with the potential to be applied as a biopreservative in food systems, providing a safe, clean-label, and efficient compound for synthetic preservatives replacement. HighlightsO_LIHerbicolin A has a strong potential as a natural preservative for food protection C_LIO_LIHerbicolin A shows lower MICs than several antifungal agents C_LIO_LIHerbicolin A is stable under heat and resistant to proteolytic degradation C_LIO_LIHerbicolin A has strong solubility and stability in a model dairy system C_LIO_LIHerbicolin A indicates low cytotoxicity against epithelial cell lines C_LI Data summaryThe authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files.

microbiology↗

bioRxiv2024

The influence of soft tissue volume on estimates of skeletal pneumaticity: implications for fossil archosaurs

Air space proportion (ASP), the volume fraction in bone occupied by air, is frequently applied as a measure for quantifying the extent of skeletal pneumaticity in extant and fossil archosaurs. Nonetheless, ASP estimates rely on a key assumption: that the soft tissue mass within pneumatic bones is negligible, an assumption that has rarely been explicitly acknowledged or tested. Here, we provide the first comparisons between estimated air space proportion (where the internal cavity of a pneumatic bone is assumed to be completely air-filled) and true air space proportion (ASPt, where soft tissues present within the internal cavities of fresh specimens are considered). Using birds as model archosaurs exhibiting postcranial skeletal pneumaticity, we find that estimates of ASPt are significantly lower than estimates of ASP, raising an important consideration that should be acknowledged in investigations of the evolution of skeletal pneumaticity and bulk skeletal density in extinct archosaurs, as well as in volume-based estimates of archosaur body mass. We advocate for the difference between ASP and ASPt to be explicitly acknowledged in studies seeking to quantify the extent of skeletal pneumaticity in extinct archosaurs, to avoid the risk of systematically overestimating the volume fraction of pneumatic bones composed of air.

evolutionary biology↗