Biology subjects

Brindefalk, B.

Publications and source records attributed to Brindefalk, B..

3 recordsLinked to original sources

bioRxiv2023

Airborne eDNA captures three decades of ecosystem biodiversity

Conserving biodiversity is a global imperative, yet our capacity to quantify and understand species occurrences has been limited. To help address this challenge, we develop a novel monitoring approach based on deep sequencing of airborne eDNA. When applied to a 34-year archive of weekly filters from an aerosol sampling station in northern Sweden, our methods enabled robust detection of over 2,700 genera across all domains of life and estimates of eDNA catchment areas. Reconstructed time series revealed regional biodiversity declines consistent with contemporary, large-scale transformations of forest composition and structure. Our results show airborne eDNA can reliably monitor biodiversity and underscore the immense latent potential in the thousands of aerosol monitoring stations deployed worldwide. One-Sentence SummaryDNA captured from air reveals organisms from all domains of life and their long-term trends.

ecology↗

bioRxiv2019

Disparate effects of antibiotic-induced microbiome change and enhanced fitness in Daphnia magna

It is a common view that an organisms microbiota has a profound influence on host fitness; however, supporting evidence is lacking in many organisms. We manipulated the gut microbiome of Daphnia magna by chronic exposure to different concentrations of the antibiotic Ciprofloxacin (0.01 - 1 mg L-1), and evaluated whether this affected the animals fitness and antioxidant capacity. In line with our expectations, antibiotic exposure altered the microbiome in a concentration-dependent manner. However, contrary to these expectations, the reduced diversity of gut bacteria was not associated with any fitness detriment. Moreover, the growth-related parameters correlated negatively with diversity indices; and, in the daphnids exposed to the lowest ciprofloxacin concentrations, the antioxidant capacity, growth, and fecundity were even higher than in control animals. These findings suggest that ciprofloxacin exerts direct stimulatory effects on growth and reproduction in Daphnia, while microbiome-mediated effects are of lesser importance. Thus, although microbiome profiling of Daphnia may be a sensitive tool to identify early effects of antibiotic exposure, disentangling direct and microbiome-mediated effects on host fitness is not straightforward.

pharmacology and toxicology↗

bioRxiv2018

Mitochondrial proline catabolism activates Ras1/cAMP/PKA-induced filamentation in Candida albicans

Amino acids are among the earliest identified inducers of yeast-to-hyphal transitions in Candida albicans, an opportunistic fungal pathogen of humans. Here, we show that the morphogenic amino acids arginine, ornithine and proline are internalized and metabolized in mitochondria via a PUT1- and PUT2-dependent pathway that results in enhanced ATP production. Elevated ATP levels correlate with Ras1/cAMP/PKA pathway activation and Efg1-induced gene expression. The magnitude of amino acid-induced filamentation is linked to glucose availability; high levels of glucose repress mitochondrial function thereby dampening filamentation. Furthermore, arginine-induced morphogenesis occurs more rapidly and independently of Dur1,2-catalyzed urea degradation, indicating that mitochondrial-generated ATP, not CO2, is the primary morphogenic signal derived from arginine metabolism. The important role of the SPS-sensor of extracellular amino acids in morphogenesis is the consequence of induced amino acid permease gene expression, i.e., SPS-sensor activation enhances the capacity of cells to take up morphogenic amino acids, a requisite for their catabolism. C. albicans cells engulfed by murine macrophages filament, resulting in macrophage lysis. Phagocytosed put1-/- and put2-/- cells do not filament and do not lyse macrophages, consistent with a critical role of mitochondrial proline metabolism in virulence.

microbiology↗