  In order to study whether there is any correlation between nuclear
activities, gas content, and the environment where galaxies reside, we have
obtained optical and millimetric spectra for a well-defined sample of
intermediate Hubble type spirals in dense environments and in the field. We
found that these spirals in dense environments have on average: less molecular
gas per blue luminosity, higher atomic gas fraction, lower current star
formation rate, and the same star formation efficiency as field galaxies.
Although none of these results stand out as a single strong diagnostic, given
their statistical significance, taken together they indicate a trend for
diminished gas content and star formation activity in galaxies in high density
environments. Our results suggest that galaxies in dense environments have
either (i) consumed their molecular gas via star formation in the past or (ii)
that dense environments leads to an inhibition of molecular gas from atomic
phase. The similarities in star formation efficiency of the dense environments
and field galaxies suggest that the physical processes controling the formation
of stars from the molecular gas are local rather than global. We also found
that star formation rate per blue luminosity increases linearly as the total
amount of gas increases in LINERs. This result, based on a small sample,
suggests that LINERs are powered by star formation rather than an AGN.
