Die Embryonalentwicklung der Paradiesschnecke ... - TOBIAS-lib

Kapitel 4
caused by torsion, streptoneury, is not so easily accessible. To determine, if
the Pt 2+ -exposed “sluggish” snails exhibit a “torted” or “untorted” nervous
system, we investigated adult sluggish snails histologically and created 3D
models of their anatomy. Additionally, we conducted immunohistochemical
analyses of the nervous system during different stages of embryonic development
of both Pt 2+ -exposed and control embryos. To label nervous tissue
we chose the two neurotransmitters, FMRFamide and serotonin, which have
already been regularly used to investigate the development of the nervous
system in gastropods (Croll, 2000; Croll and Voronezhskaya, 1996; Goldberg
and Kater, 1989; Page, 2003, 2006a) and other molluscs (Voronezhskaya et
al., 2008; Wanninger and Haszprunar, 2003). Furthermore, we investigated
acetylated alpha-tubulin which has been used several times in examinations
of the nervous system in gastropods (Jackson et al., 1995; Kempf and Page,
2005). Using an animal model which does not undergo ontogenetic torsion
we aimed at elucidating the question whether (ontogenetic) torsion really is
the prerequisite for the formation of streptoneury in M. cornuarietis snails.
Methods
The experiments were conducted on the basic of the M. cornuarietis embryo
test (MariETT) developed by Schirling et al. (2006) and modified. For a
detailed description of material, techniques and keeping of M. cornuarietis
see Osterauer et al. (2010b) and Marschner et al. (2012; 2013). Freshly
fertilized eggs were transferred into Petri dishes (20 eggs each) containing
either aquarium water for the control or a 200 µg/l PtCl 2 -solution made
from one liter aquarium water and 200 µl PtCl 2 (Platinum Standard, Ultra
Scientific, Wesel, Germany, 1000 µg/ml, Matrix: 98% water, 2% HCl). The
Petri dishes were kept at 26 ◦ C in a climate chamber at a light-dark regime
of 12:12 h. The test solutions were changed on a daily basis.
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