Biology subjects

Fraser, R.

Publications and source records attributed to Fraser, R..

4 recordsLinked to original sources

bioRxiv2025

A novel vaccination strategy induces vaccine-specific mucosal responses at port of viral entry and exit: using systemic SARS-CoV-2 vaccination as a test case

Respiratory infectious diseases are associated with substantial morbidity and mortality rates worldwide, especially at the extremes of age and in immunocompromised individuals. Over the past two decades, respiratory viruses have driven nine epidemics and pandemics (including the COVID-19 pandemic); and their ongoing emergence, persistence and evolution continue to threat global health security. The upper respiratory tract (URT) represents the primary access point for respiratory viruses, where initial host infection occurs. Vaccine-mediated URT mucosal memory responses can control infection, prevent transmission and limit viral evolution. However, vaccines against respiratory viruses predominantly have systemic administration routes that elicit strong responses in the circulation to prevent severe respiratory disease, but do not effectively block infection and onward community transmission. To overcome the limitations of systemic vaccination alone, we present a novel intervention combining systemic vaccination with targeted non-antigenic inflammatory stimulation of the URT, to induce vaccine-specific immune responses in the URT mucosa. Using SARS-CoV-2 vaccination as a test case, we demonstrate for the first time, that intranasal coadministration of exogenous IFN- as a targeted inflammatory URT signal, alongside systemic vaccination, induces vaccine-specific T-cell responses in the URT.

immunology↗

bioRxiv2024

Recurrent sex chromosome turn-over in termites

Termites, together with cockroaches, belong to the Blattodea. They possess an XX/XY sex determination system which has evolved from an XX/X0 system present in other Blattodean species such as cockroaches and wood roaches. Little is currently known about the sex chromosomes of termites, their gene content, or their evolution. We here investigate the X chromosome of multiple termite species and compare them to the X chromosome of cockroaches using genomic and transcriptomic data. We find that the X chromosome of the termite Macrotermes natalensis is large and differentiated showing hall marks of sex chromosome evolution such as dosage compensation, while this does not seem to be the case in the other two termite species investigated here where sex chromosomes are probably evolutionary young. Furthermore, that X chromosome in M. natalensis is different from the X chromosome found in the cockroach Blattella germanica indicating at least one, potentially multiple, sex chromosome turn-over events during termite evolution.

evolutionary biology↗

bioRxiv2023

Intracellular Pseudomonas aeruginosa within the airway epithelium of Cystic Fibrosis lung tissues

RATIONALEPseudomonas aeruginosa (P.a.) is the major bacterial pathogen colonizing the airways of adult cystic fibrosis (CF) patients and causes chronic infections that persist despite antibiotic therapy. Intracellular bacteria may represent an unrecognized reservoir of bacteria that evades the immune system and antibiotic therapy. While the ability of P.a. to invade and survive within epithelial cells has been described in vitro in different epithelial cell models, evidence of this intracellular lifestyle in human lung tissues is currently lacking. OBJECTIVESTo detect and characterize intracellular P.a. in CF airway epithelium from human lung explant tissues. METHODSWe sampled the lung explant tissues from CF and non-CF patients undergoing lung transplantation and analyzed lung tissue sections for the presence of intracellular P.a. by quantitative culture and microscopy, in parallel to histopathology and airway morphometry. MEASUREMENTS AND MAIN RESULTSP.a. was isolated from the lungs of 7 CF patients undergoing lung transplantation. Microscopic assessment revealed the presence of intracellular P.a. within airway epithelial cells in 3 out of the 7 lungs analyzed, at a varying but rare frequency. We observed those events occurring in lung regions with high bacterial burden. CONCLUSIONThis is the first study describing the presence of intracellular P.a. in CF lung tissues. While intracellular P.a. in airway epithelial cells are likely relatively rare events, our findings highlight the plausible occurrence of this intracellular bacterial reservoir in chronic CF infections.

microbiology↗

bioRxiv2020

All protein aggregates will thermodynamically order

Proteins can aggregate into disordered liquid droplets or ordered assemblies such as amyloid fibrils. These two distinct phases determine the spatial organization within cells and serve differing roles in a wide range of biological functions including gene regulation, organelle and synapse formation, and memory consolidation. The ordered phase can also give rise to diseases such as Alzheimers. However, how the protein sequence determines aggregation fate is an open question. Here we establish a general statistical mechanical theory of the disordered-to-ordered transition for polymer aggregates, including proteins, thereby completing the phase diagram for this general class of matter. The theory produces a simple universal equation determining the favored phase as a function of the temperature, polymer length, and inter-residue interaction energy variance. We show that the sequence-dependent energy variance can be efficiently calculated from all-atom molecular dynamics simulations, so that the theory has no adjustable parameters. The equation accurately predicts the experimental length-dependent crystallization temperature of synthetic polymers. The theory shows that all protein aggregates, regardless of sequence, will thermodynamically order, even in the most extreme thermophiles. Therefore, energy must be expended to maintain the disordered protein aggregate at steady state. More broadly, the theory establishes a lower bound on the ordering transition temperature for polymers. This bound indicates that condensates of any organic polymer will spontaneously order on all habitable planets.

biophysics↗