Biology subjects

Skold, M.

Publications and source records attributed to Skold, M..

4 recordsLinked to original sources

bioRxiv2025

The effect of Shifts in Fish Community Structure on PCDD/F temporal variability in common guillemot (Baltic Sea)

Persistent Organic Pollutants, specifically polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) (PCDD/Fs) threaten marine ecosystems through biomagnification and bioaccumulation in top predators. Following environmental legislation introduction in the 1970s, PCDD/F concentrations declined in the Baltic Sea biota. However, previous studies signaled that this decline plateaued from the 1990s onward in common guillemot (Uria aalge) eggs. This period coincides with shifts in Baltic environmental conditions and food-web structure, including guillemot prey species. Here, we hypothesize that temporal variability of PCDD/Fs in guillemot eggs was driven by changing environmental conditions and food-web structure affecting prey availability. We identified phases in the temporal dynamic of fish community structure, linked them to PCDD/Fs rate of change, and identified potential environmental and anthropogenic drivers of these phases. Three distinct phases emerged: cod and herring dominance (1976-1986), sprat dominance (1987-2001), and stickleback increase (2002-2021). PCDD/F concentrations declined sharply during the first phase (-6.4% y1), plateaued during the second (0.27% y1), and resumed a decline during the third (-3.8% y1). The transition to a sprat-dominated phase increased guillemots dietary exposure to PCDD/Fs, contributing to the second phase plateau. Conversely, stickleback rise as a potential key prey species during the third phase may have facilitated the post-2002 decline. Shifts in fish community structure were driven by changes in temperature, salinity, zooplankton size, and fishing pressure. We conclude that both bottom-up (environmental conditions) and top-down (fisheries food-web dynamics) effects have cascaded through the ecosystem, reshaping fish community structure and influencing PCDD/F concentrations in guillemot eggs.

ecology↗

bioRxiv2024

Quantifying competition between two demersal fish species from spatiotemporal stomach content data

Inference on competition is often made on indirect patterns of potential competition, such as population trends and spatiotemporal overlap in diet and distribution. However, these indicators do not test if the contested resources are limited in supply, nor if they decline as competitor biomass increases. Using stomach content and biomass data, we evaluate food competition between Atlantic cod (Gadus morhua) and flounder (Platichthys spp.) in the Baltic Sea. We quantify diet overlap and fit geostatistical mixed models to evaluate effects of local-scale covariates on stomach contents. The dietary overlap is low and does not decline with predator density. We find that cod feed less on the isopod Saduria entomon at high flounder densities. However, the total prey weight in cod is not affected by flounder densities. This suggests interspecific food competition is not limiting the overall feeding of cod, but affects its diet composition. In addition, we find support for intraspecific food competition in large cod and flounder. Our study illustrates the importance of local-scale processes when inferring competition from stomach content data.

ecology↗

bioRxiv2020

Decreased miR-24-3p potentiates DNA damage responses and increases susceptibility to COPD

Activation of the DNA damage response (DDR) due to chronic exposure to cigarette smoke (CS) is implicated in the pathogenesis of Chronic Obstructive Pulmonary Disease (COPD). However, not all smokers develop COPD and the pathologic consequences of CS exposure are heterogenous. Cellular mechanisms that regulate the DDR and contribute to disease progression in susceptible individuals are poorly understood. Because microRNAs are well known regulators of the DDR, we evaluated microRNA expression arrays performed on lung samples from 172 subjects with and without COPD. We identified miR-24-3p as the microRNA best correlated with radiographic emphysema ({rho}=-0.353, P=1.3e-04) and validated this finding in multiple cohorts. In a CS-exposure mouse model, miR-24-3p inhibition increased emphysema severity. In human airway epithelial cells, miR-24-3p suppressed apoptosis through the BH3-only protein BIM and suppressed homology-directed DNA repair and the DNA repair protein BRCA1. Finally, we found BIM and BRCA1 were increased in COPD lung tissue and inversely correlated with miR-24-3p expression. We concluded that decreased miR-24-3p expression increases COPD susceptibility and potentiates the DDR through BIM and BRCA1.

cell biology↗

bioRxiv2018

The Viral protein Corona Directs Viral Pathogenesis and Amyloid Aggregation

Artificial nanoparticles accumulate a protein corona layer in biological fluids, which significantly influences their bioactivity. As nanosized obligate intracellular parasites, viruses share many biophysical properties with artificial nanoparticles in extracellular environments and here we show that respiratory syncytial virus (RSV) and herpes simplex virus 1 (HSV-1) accumulate a rich and distinctive protein corona in different biological fluids. Moreover, we show that corona pre-coating differentially affects viral infectivity and immune cell activation. Additionally, we demonstrate that viruses bind amyloidogenic peptides in their corona and catalyze amyloid formation via surface-assisted heterogeneous nucleation. Importantly, we show that HSV-1 catalyzes the aggregation of the amyloid beta peptide (A{beta}42), a major constituent of amyloid plaques in Alzheimers disease, in-vitro and in animal models. Our results highlight the viral protein corona as an acquired structural layer that is critical for viral-host interactions and illustrate a mechanistic convergence between viral and amyloid pathologies.

microbiology↗