The myxomycete Fuligo septica, colloquially referred to as "dog vomit fungus", forms vibrant yellow fruiting bodies (aethalia) on wood chips during warm and humid conditions in spring. In 2018, ideal climatic conditions in Sydney, Australia, provided a rare opportunity to access abundant quantities of F. septica aethalia, which enabled the isolation, purification, structure elucidation, and biological screening of two avenalumamide pyrones, fuligopyrone (1) and fuligopyrone B (2). While 1 and 2 did not exhibit any appreciable biological activity, their significant UV absorption at 325 nm suggested they may be acting as transient sunscreens to help protect the fruiting mass from exposure to sunlight. In support of this hypothesis, exposing a solution of 2 to direct sunlight for 5 min resulted in rapid equilibration with a mixture of 2E,4Z-fuligopyrone B (10) and 2Z,4E-fuligopyrone B (11) photoisomers.

Background Skin diseases in cattle pose significant animal welfare issues and financial burdens. Microbial communities inhabiting the skin have essential roles in maintaining host health. Microbiota manipulation can be an efficient strategy for improving the productivity and sustainability of skin disease management. However, a lack of information on the skin microbiota of healthy cattle and how environmental and host factors drive its normal variation has limited using skin microbes for diagnosing or treating skin disease and pest infestation in cattle. Here, we profiled the skin microbiota of 1,734 healthy cattle from 25 different herds located in a 187,000 km2 area in the northeast to east Australia using 16S rRNA gene amplicon sequencing. The impact of host and climatic conditions on the skin microbial populations was examined. Results Our results demonstrate a highly diverse microbiota on the skin of healthy cattle. While the structure and diversity of microbial communities varied between herds, several bacteria were present consistently despite the differences in environmental conditions. For example, bacterial families Moraxellaceae, Sphingomonadaceae, Bacillaceae and Burkholderiaceae were observed in most cattle, however, their relative abundance varied significantly between herds. Solar exposure and rainfall were key factors contributing to the observed variations in skin microbiota between herds, while temperature and cattle breed did not show any statistically significant impact on the composition of cattle skin microbiota. Conclusions This is the first report of the composition of the commensal skin microbiota of healthy cattle, specifically herds located in the northeast to east Australia and the impact of environmental and host variables on these microbial communities. Our study provides valuable insight into normal variation in cattle skin microbiota, an essential step for developing skin microbiota-based therapies for skin disease present in cattle.

Turonicin A (1) was isolated from Streptomyces sp. MST-123921, which was recovered from soil collected on the banks of the Turon River in New South Wales, Australia. Turonicin A (1) is an amphoteric linear polyene polyketide featuring independent pentaene and tetraenone chromophores and is structurally related to linearmycins A−C (2−4). The structure of 1 was determined by detailed spectroscopic analysis and comparison to literature data. Bioinformatic analysis of the linearmycin biosynthetic gene cluster also allowed the previously unresolved absolute stereostructures of 2−4 to be elucidated. Turonicin A (1) exhibited very potent activity against the fungi Candida albicans (MIC 0.0031 μg/mL, 2.7 nM) and Saccharomyces cerevisiae (MIC 0.0008 μg/mL, 0.7 nM), moderate activity against the bacteria Bacillus subtilis (MIC 0.097 μg/mL, 85 nM) and Staphylococcus aureus (MIC 0.39 μg/mL, 340 nM), and no cytotoxicity against human fibroblasts, making it an attractive candidate for further development as a potential next-generation antibiotic scaffold.