Biology subjects

Nilsen, K.

Publications and source records attributed to Nilsen, K..

3 recordsLinked to original sources

bioRxiv2025

A longitudinal evaluation of localised chronic Pseudomonas aeruginosa infection in cystic fibrosis rat models

Recurrent bacterial infections with Pseudomonas aeruginosa result in chronic airway inflammation, lung damage and eventual respiratory failure, and are the major cause of morbidity and mortality in people with cystic fibrosis (CF). Animal models are essential for understanding disease progression and assessing potential treatments in the presence of infection. Previously reported P. aeruginosa lung infection rodent models for CF research have some weakness, including acute infection rather than chronic, associated mortality, use of laboratory strains of P. aeruginosa and the use of non-CF rodents. The aim of this study was to create a localised P. aeruginosa infection in wildtype and two CF rat models, by delivering bacteria embedded agar beads using a miniature bronchoscope. The resulting infection was well tolerated by all animals of all genotypes with no mortality associated with the procedure or infection. Histologically the affected regions were localised to the right lung, with bronchopneumonia present. Bacteria persisted for 9 weeks (63 days) in all genotypes, with lung function changes observed by day 63 of the infection.

pathology↗

bioRxiv2024

A pangenome and pantranscriptome of hexaploid oat

Oat grain is a traditional human food rich in dietary fiber that contributes to improved human health. Interest in the crop has surged in recent years owing to its use as the basis for plant-based milk analogs. Oat is an allohexaploid with a large, repeat-rich genome that was shaped by subgenome exchanges over evolutionary timescales. In contrast to many other cereal species, genomic research in oat is still at an early stage, and surveys of structural genome diversity and gene expression variability are scarce. Here, we present annotated chromosome-scale sequence assemblies of 33 wild and domesticated oats along with an atlas of gene expression across six tissues of different developmental stages in 23 accessions. We describe the interplay of gene expression diversity across subgenomes, accessions and tissues. Gene loss in the hexaploid is accompanied by compensatory up-regulation of the remaining homeologs, but this process is constrained by subgenome divergence. Chromosomal rearrangements have significantly impacted recent oat breeding. A large pericentric inversion associated with early flowering explains distorted segregation on chromosome 7D and a homeologous sequence exchange between chromosomes 2A and 2C in a semidwarf mutant has risen to prominence in Australian elite varieties. The oat pangeome will promote the adoption of genomic approaches to understanding the evolution and adaptation of domesticated oats and will accelerate their improvement.

genomics↗

bioRxiv2024

Functional lung imaging identifies peripheral ventilation changes in mice with muco-obstructive lung disease

{beta}-ENaC-Tg mice serve as a relevant model of muco-obstructive lung disease, with impaired mucociliary clearance, mucus obstruction, chronic airway inflammation, structural lung damage, and altered lung function. The aim of this study was to undertake a comprehensive lung function and mechanics analysis of the adult {beta}-ENaC-Tg model. {beta}-ENaC-Tg and wild-type littermates underwent X-ray Velocimetry (XV) scans using a Permetium XV scanner (4DMedical, Melbourne, Australia). For comparative lung mechanics, lung function assessments were conducted with a flexiVent system. XV imaging demonstrated elevated ventilation defect percentage, mean specific ventilation, and ventilation heterogeneity in {beta}-ENaC-Tg mice. Spatial analysis of ventilation maps indicated increased ventilation variability in the peripheral lung regions, as well as an increased proportion of under-ventilated areas. The flexiVent analysis indicated that compared to wild-types, {beta}-ENaC-Tg mice have a significantly more compliant lungs with increased inspiratory capacity, reduced tissue elastance and increased hysteresivity (heterogeneity), suggesting loss of parenchymal integrity. This research highlights the utility of XV imaging in evaluating ventilation defects in the {beta}-ENaC-Tg model and provides a comprehensive lung function analysis.

physiology↗