Allogeneic and xenogeneic grafts in pulmonate gastropod molluscs: fates of neural transplants.

Neural intracerebral allo- and xenografts in pulmonate gastropods demonstrated a variation in the tolerance of neural xenogeneic grafts that was dependent on the phylogenetic distance between the donor and the host. Like allografts, neural congeneric xenografts (Hp/Haa and H1/Haa) of cerebral ganglia (CG) were tolerated and restored growth in juvenile mesocerebrum-deprived (Haa) snails. However, CG neural xenografts between different genera of stylommatophorans (Achatina fulica/Haa) or between genera of different orders (Lymnaea stagnalis: Basommatophora/Haa: Stylommatophora) revealed an interspecific histoincompatibility.

Brain grafts of cerebral ganglia have effectiveness in growth restoration of damaged Helix aspersa mesocerebrum.

The microsurgical extirpation of the mesocerebrum from the brain of fast-growing juvenile snails (Helix aspersa aspersa: H.a.a.

[Study of mitochondrial DNA in Helix land snails by PCR-RFLP].

Sometimes the morphological criteria--used to distinguish between 4 land snails species (Helix pomatia, Helix lucorum, Helix aspersa aspersa and Helix aspersa maxima)--are little pronounced and ambiguous. We have selected mitochondrial DNA, a widely used molecular marker, in order to have a reliable technique of distinction between the 4 studied species. After extraction, mtDNA is amplified by PCR and digested with several enzymes.

In vitro effect of the gonad of Helix aspersa (Mollusca) on galactogen synthesis in the albumen gland of either mated or virgin snails.

The gonad of Helix aspersa contains a factor which can stimulate in a dose-dependent manner galactogen synthesis in albumen gland explants cultured in vitro. The stimulatory activity appears to be greater when the gonad is predominantly male than when it is predominantly female. The albumen gland of virgin snails does not respond in vitro to the gonadal influence.

[Influence of brain grafts on growth restoration of snail (Helix aspersa) deprived of the midbrain].

Microsurgical removal of the mesocerebrum from the brain of juvenile snails stopped their growth whereas intracerebral implantation of desheathed cerebral ganglia (CG) re-established it. When the animals were grafted with CG from very young snails growth was much more stimulated than with CG from donors of the same age or from adults. Furthermore, young CG of juvenile fast growing specimens of the large species (Helix aspersa maxima) induced a higher growth rate than the CG of the ordinary small garden snails (Helix aspersa aspersa).