Characterisation of N-linked protein glycosylation in the bacterial pathogen Campylobacter hepaticus.

Campylobacter hepaticus is an important pathogen which causes Spotty Liver Disease (SLD) in layer chickens. SLD results in an increase in mortality and a significant decrease in egg production and therefore is an important economic concern of the global poultry industry. The human pathogen Campylobacter jejuni encodes an N-linked glycosylation system that plays fundamental roles in host colonization and pathogenicity. While N-linked glycosylation has been extensively studied in C. jejuni and is now known to occur in a range of Campylobacter species, little is known about C. hepaticus glycosylation. In this study glycoproteomic analysis was used to confirm the functionality of the C. hepaticus N-glycosylation system. It was shown that C. hepaticus HV10T modifies > 35 proteins with an N-linked heptasaccharide glycan. C. hepaticus shares highly conserved glycoproteins with C. jejuni that are involved in host colonisation and also possesses unique glycoproteins which may contribute to its ability to survive in challenging host environments. C. hepaticus N-glycosylation may function as an important virulence factor, providing an opportunity to investigate and develop a better understanding the system's role in poultry infection.

A Toxic Synergy between Aluminium and Amyloid Beta in Yeast.

Alzheimer's disease (AD), the most prevalent, age-related, neurodegenerative disease, is associated with the accumulation of amyloid beta (Aß) and oxidative stress. However, the sporadic nature of late-onset AD has suggested that other factors, such as aluminium may be involved. Aluminium (Al3+) is the most ubiquitous neurotoxic metal on earth, extensively bioavailable to humans. Despite this, the link between Al3+ and AD has been debated for decades and remains controversial. Using Saccharomyces cerevisiae as a model organism expressing Aß42, this study aimed to examine the mechanisms of Al3+ toxicity and its interactions with Aß42. S. cerevisiae cells producing Aß42 treated with varying concentrations of Al3+ were examined for cell viability, growth inhibition, and production of reactive oxygen species (ROS). Al3+ caused a significant reduction in cell viability: cell death in yeast producing green fluorescent protein tagged with Aß42 (GFP-Aß42) was significantly higher than in cells producing green fluorescent protein (GFP) alone. Additionally, Al3+ greatly inhibited the fermentative growth of yeast producing GFP-Aß42, which was enhanced by ferric iron (Fe3+), while there was negligible growth inhibition of GFP cells. Al3+- induced ROS levels in yeast expressing native Aß42 were significantly higher than in empty vector controls. These findings demonstrate Al3+ has a direct, detrimental toxic synergy with Aß42 that can be influenced by Fe3+, causing increased oxidative stress. Thus, Al3+ should be considered as an important factor, alongside the known characteristic hallmarks of AD, in the development and aetiology of the disease.