  We study eta meson properties in the infinite nuclear matter and in atomic
nuclei with an emphasis on effects of the eta coupling to
N*(1535)--nucleon-hole modes. The N*(1535) resonance, which dominates the
low-energy eta-nucleon scattering, can be seen as a chiral partner of the
nucleon. The change of the chiral mass gap between the N* and the nucleon in a
nuclear medium has an impact on the properties of the eta-nucleus system. If
the N*-nucleon mass gap decreases with a density increase (chiral symmetry
restoration) the calculations show the existence of the resonance state at the
energy about 60 MeV and two bound eta-nucleus states with the binding energies
about -80 MeV. These states can have strong effect on predicted cross sections
of the ^12C (gamma,p) ^11B reaction with eta-meson production.
