Influenza A virus hemagglutinin prevents extensive membrane damage upon dehydration

Abstract

While the molecular mechanisms of virus infectivity are rather well known, the detailed consequences of environmental factors on virus biophysical properties are poorly understood. Seasonal influenza outbreaks are usually connected to the low winter temperature, but also to the low relative air humidity. Indeed, transmission rates increase in cold regions during winter. While low temperature must slow degradation processes, the role of low humidity is not clear. We studied the effect of relative humidity on a model of influenza A H1N1 virus envelope, a supported lipid bilayer containing the surface glycoprotein hemagglutinin (HA), which is present in the viral envelope in very high density. For complete cycles of hydration, dehydration and rehydration, we evaluate the membrane properties in terms of structure and dynamics, which we assess by combining confocal fluorescence microscopy, raster image correlation spectroscopy, line-scan fluorescence correlation spectroscopy and atomic force microscopy. Our findings indicate that the presence of HA prevents macroscopic membrane damage after dehydration. Without HA, fast membrane disruption is followed by irreversible loss of lipid and protein mobility. Although our model is principally limited by the membrane composition, the macroscopic effects of HA under dehydration stress reveal new insights on the stability of the virus at low relative humidity.

Moral dilemmas in food provisioning: Inflation, the claim for ‘just prices’ and for ‘fair wages’

“…Roig says that 'we have stressed suppliers so much that some have stopped producing'. 12 As a subtext, in farmers and food distributors' arguments, we find implications that unsustainable 'production costs' feeding inflation are respectively caused by minimum wage raises and by the new law of the supply chain of December 2021 (BOE, 2021), that followed an urgent Royal Decree in February 2020. We turn now to these issues as they are expressed in the 'just price' conflicts.…”

“…A distributor such as Mercadona declared that while their costs had increased 12%, they were only passing on 10% to the consumer and their profit margin had decreased around 0.5% even as their profits had increased 5.6% in 2022. 32 What seems to transpire from this situation is that while corporate profits have driven inflation post-pandemic, 33 economic institutions vow to contain wages with the argument that wage increase would create spiraling inflation. 34 Moreover, the rise in interest rates to contain inflation is affecting the mortgage costs of many households.…”