Biology subjects

Angell, I. L.

Publications and source records attributed to Angell, I. L..

5 recordsLinked to original sources

bioRxiv2024

Key roles of microbial sulfur and ammonium oxidizers for the coastal seafloor ecological state

Recent evidence suggests that there is a major switch in coastal seafloor microbial ecology already at a mildly deteriorated macrofaunal state. This knowledge is of critical value in the management and conservation of the coastal seafloor. We therefore aimed to determine the relationships between seafloor microbiota and macrofauna on a regional scale. We compared prokaryote, macrofauna, chemical, and geographical data from 1,546 seafloor samples which varied in their exposure to aquaculture activities along the Norwegian and Icelandic coasts. We found that the seafloor samples contained either a sulfur oxidizer network (42.4% of samples, n=656), or an ammonium oxidizer network of microbes (44.0% of samples, n=681). Very few samples contained neither network (9.8% of samples, n=151), or both (3.8% of samples, n=58). Samples with a sulfur oxidizer network had a tenfold higher risk of macrofauna loss (odds ratios, 95% CI: 9.5 to 15.6), while those with an ammonium oxidizer network had a tenfold lower risk (95% CI: 0.068 to 0.11). The sulfur oxidizer network was negatively correlated to distance from Norwegian aquaculture sites (Spearman rho = -0.42, p < 0.01), and was present in all Icelandic samples (n=274). The ammonium oxidizer network was absent from Icelandic samples, and positively correlated to distance from Norwegian aquaculture sites (Spearman rho = 0.67, p < 0.01). Based on 357 high-quality metagenome-assembled genomes (MAGs), we found that the main metabolic process for the ammonium oxidizer network was cobalamin-dependent, while the sulfur oxidizer network was associated with both ammonium retention and sulfur metabolism. In conclusion, our findings highlight the critical roles of sulfur and ammonium oxidizers in mild macrofauna deterioration, which should be included as an essential part of seafloor surveillance.

microbiology↗

bioRxiv2022

The effect of dietary chitin on Atlantic salmon (Salmo salar) chitinase activity, gene expression, and microbial composition

BackgroundChitin is a common component in the natural diet of many fish, and a range of chitinases with the potential to down chitin have been identified. Yet whether chitin is metabolized in fish is still unclear. Here we used a combination of chitinase activity assay, transcriptomics, and 16S rRNA bacterial analysis to assess the effect of chitin supplementation on Atlantic salmon gene expression and microbial community. ResultsAtlantic salmon express multiple genes associated with chitin metabolism, and we show that the expression and activity of Atlantic salmon chitinases are not affected by the addition of dietary chitin. We do, however, demonstrate an association between gut microbial composition, chitinase activity in the gut, and host chitinase expression. ConclusionThe findings presented here support the idea that chitin metabolism genes are linked to the maintenance of a chitin-based barrier in the teleost gut. These results contribute to a greater understanding of chitin metabolism in fish.

genetics↗

bioRxiv2020

Association of gut microbiota with metabolism in juvenile Atlantic Salmon

The gut microbiome plays a key role in animal health and metabolism through the intricate functional interconnection between the feed, gut microbes, and the host. Unfortunately, in aquaculture, the links between gut microbes and fish genetics and production phenotypes are not well understood. In this study, we investigate the associations between gut microbial communities, fish feed conversion, and fish genetics in the domestic Atlantic salmon. Microbial community composition was determined for 230 juvenile fish from 23 full-sib families and was then regressed on growth, carbon and nitrogen metabolism, and feed efficiency. We only found weak associations between host genetics and microbial composition. However, we did identify significant (p < 0.05) associations between the abundance of three microbial operational taxonomical units (OTUs) and fish metabolism phenotypes. Two OTUs were associated with both carbon metabolism in adipose tissue and feed efficiency, while a third OTU was associated with weight gain. In conclusion, this study demonstrates an intriguing association between host lipid metabolism and the gut microbiota composition in Atlantic salmon.

genetics↗

bioRxiv2019

Lysates of Methylococcus capsulatus Bath induce a lean-like microbiota, intestinal FoxP3+RORγt+IL-17+ Tregs and improve metabolism

Interactions between host and gut microbial communities may be modulated by diets and play pivotal roles in securing immunological homeostasis and health. Here we show that intake of feed based on whole-cell lysates of the non-commensal bacterium Methylococcus capsulatus Bath (McB) as protein source reversed high fat high sucrose-induced changes in the gut microbiota to a state resembling that of lean, low fat diet-fed mice, both under mild thermal stress (T22{degrees}C) and at thermoneutrality (T30{degrees}C). McB feeding selectively upregulated triple positive (Foxp3+ROR{gamma}t+IL-17+) regulatory T cells in the small intestine and colon, and enhanced mucus production and glycosylation status suggesting improved gut health. Mice receiving McB lysates further exhibited improved glucose regulation, reduced body and liver fat along with diminished hepatic immune infiltration. Collectively, these data points towards profound whole-body effects elicited by the McB lysate suggesting that it may serve as a potent modulator of immunometabolic homeostasis.

immunology↗

bioRxiv2017

Genetic diversity and mother-child overlap of the gut associated microbiota determined by reduced genome sequencing

The genetic diversity and sharing of the mother-child associated microbiota remain largely unexplored. This severely limits our functional understanding of gut microbiota transmission patterns. The aim of our work was therefore to use a novel reduced metagenome sequencing in combination with shotgun and 16S rRNA gene sequencing to determine both the metagenome genetic diversity and the mother-to-child sharing of the microbiota. For a cohort of 17 mother-child pairs we found an increase of the collective metagenome size from about 100 Mbp for 4-day-old children to about 500 Mbp for mothers. The 4-day-old children shared 7% of the metagenome sequences with the mothers, while the metagenome sequence sharing was more than 30% among the mothers. We found 15 genomes shared across more than 50% of the mothers, of which 10 belonged to Clostridia. Only Bacteroides showed a direct mother-child association, with B. vulgatus being abundant in both 4-day-old children and mothers. In conclusion, our results support a common pool of gut bacteria that are transmitted from adults to infants, with most of the bacteria being transmitted at a stage after delivery.

microbiology↗