  We study the Casimir effect for free massless scalar fields propagating on a
two-dimensional cylinder with a metric that admits a change of signature from
Lorentzian to Euclidean. We obtain a nonzero pressure, on the hypersurfaces of
signature change, which destabilizes the signature changing region and so
alters the energy spectrum of scalar fields. The modified region and spectrum,
themselves, back react on the pressure. Moreover, the central term of
diffeomorphism algebra of corresponding infinite conserved charges changes
correspondingly.
