Figure 1.
Phylogenic tree of all extant bat families.
Names of species included in this study in brackets behind the corresponding family (adapted from Teeling et al. 2005 [43]).
Figure 2.
Proliferating and migrating young neurons in the hippocampus of four representative bat species.
In the dentate gyrus of nectar and fruit eating Phyllostomus discolor (A,E,I) as well as in the insectivorous Hipposideros cyclops (B,F,J) we did not detect any proliferating cells with antibodies against Ki-67 (A,B) and MCM2 (E,F), no migrating new neurons can be found with antibody agains DCX (I,J). In contrast, in the sister species Hipposideros caffer (C,G,K) and in Mops condylurus (D,H,L), proliferating as well as migrating cells can be detected in the subgranular layer of the hippocampus (Ki-67: C,D; MCM2: G,H; DCX: K,L) Molecular layer in all examples on the right side of the granule cell layer, arrows indicate immunopositive cells. Scale bar is 20µm.
Table 1.
Summary of investigated animals and qualitative immunohistochemical results
Figure 3.
Neurogenesis is not abolished in the rostral migratory stream; NeuroD immunoreactivity has an irregular distribution.
Examples of proliferating cells in the rostral migratory stream detected with antibody against Ki-67 (A–D) as well as their neuronal fate visualized with DCX (E–H) are illustrated for Phyllostomus discolor (A,E), Hipposideros cyclops (B,F), Hipposideros caffer (C,G), and Mops condylurus (D,H). Thus, animals with and without hippocampal neurogenesis do not differ in their neurogenetic activity in the rostral migratory stream. In Phyllostomus discolor, all granule cells in the hippocampus are positive for NeuroD (I), in Hipposideros cyclops (J), Hipposideros caffer (K) and Mops condylurus (L) no reactivity to the antibody against NeuroD could be detected. Scale bar is 20µm.
Figure 4.
Mice and bats show similar proliferation activity in the RMS, but not in the hippocampus.
Immunohistochemistry against Ki-67 in wild trapped adult wood mouse (Apodemus flavicollis: A,C,D) shows intense proliferation activity in the RMS (A, insert C) as well as in the subgranular layer of the dentate gyrus (A, insert D). The same protocol applied to a neotropical bat (Phyllostomus discolor: B,E,F) visualizes a continuous band of proliferating cells along the RMS (B, insert E), but proliferating cells are completely missing in the granule cell layer (B, insert F). Scale bar in A,B is 1mm, in C-F 25µm.