Effect of high hydrostatic pressure on the bacterial mechanosensitive channel MscS

We have investigated the effect of high hydrostatic pressure on MscS, the bacterial mechanosensitive channel of small conductance. Pressure affected channel kinetics but not conductance. At negative pipette voltages (corresponding to membrane depolarization in the inside-out patch configuration used in our experiments) the channel exhibited a reversible reduction in activity with increasing hydrostatic pressure between 0 and 900 atm (90 MPa) at 23 degrees C. The reduced activity was characterized by a significant reduction in the channel opening probability resulting from a shortening of the channel openings with increasing pressure. Thus high hydrostatic pressure generally favoured channel closing. Cooling the patch by approximately 10 degrees C, intended to order the bilayer component of the patch by an amount similar to that caused by 50 MPa at 23 degrees C, had relatively little effect. This implies that pressure does not affect channel kinetics via bilayer order. Accordingly we postulate that lateral compression of the bilayer, under high hydrostatic pressure, is responsible. These observations also have implications for our understanding of the adaptation of mechanosensitive channels in deep-sea bacteria

Rhinoviruses

Picornaviruses, which include the human rhinoviruses (HRVs) and enteroviruses (EVs), are the most frequent cause of acute human illness worldwide. HRVs are the most prevalent cause of acute respiratory tract illnesses (ARIs) which usually commence in the upper respiratory tract (URT). ARIs are the leading cause of morbidity in children under 5 years and occur in all seasons. ARIs linked to HRV infections are associated with excessive and perhaps inappropriate antibiotic prescribing and with significant direct and indirect healthcare expenditure. ARI incidence is highest in the first 2 years of life, with up to thirteen episodes per year including up to six positive for an HRV, and it is not uncommon to average one infection per child-month