Ultrastructural study on host-guest relationships between anuran serous glands and nematodes

We described guest nematodes in serous and lipid skin glands in two anuran species from the Old and New Worlds: Rana camerani and Phyllomedusa hypochondrialis, respectively. These glands are involved in three types of response: a) invaginations from the periluminal plasma membrane which accommodate the “round worms”; b) secretory release into such hosting chambers; c) migration of macrophages from the periglandular stroma to the secretory unit. There are no obvious signs suggesting the glands are harmed by the nematodes, nor are the latter affected by defence reactions, either secretory or cell-mediated, of their hosts. Nematodes are natural tracers which allow analysis of the inner space system (lumina as well as interstitia) in the glands. Furthermore, they provide the opportunity for functional characterisation of anuran serous glands under intrusion stress, revealing peculiar reactive traits, namely a pliable periluminal plasma membrane and inducible processes of secretory release.