The presence of dense glycosylated granules was detected bymeans
of light and epifluorescentmicroscopy and the Alcian blue-Periodic Acid
Schiff staining method (AB-PAS). In gill tissues from animals immediately
retrieved from vents, the goblet mucus cells contained granules
that fluoresced underUV light (Fig. 2). These granuleswere visible in the
gill filaments for severalmonths until complete disappearance fromthe
distal ends of the lamellae (Fig. 3). Some granules appear to be stained
with the Alcian blue and Periodic-Acid Schiff stain,which indicates that
they contained proteoglycans or glycoproteins (Figs. 2 and 3) although
the staining is also shown in the main cell content (Fig. 2A, inset). A
higher magnification of a broken lamellae revealed that the granules
appear to be spherical and approximately 2 μm diameter and colored
magenta and dark blue, revealing thus their neutral and acidic polysaccharide
nature respectively (Fig. 2E). After 3 monthsmaintenance in
aquaria, the granules were no longer visible, under UV light.