The distribution of biota from the temperate regions changed considerably during the climatic fluctuations of the Quaternary. This is especially true for many bat species that depend on warm roosts to install their nursery colonies. Surveys of genetic variation among European bats have shown that the southern peninsulas (Iberia and the Balkans) harbour endemic diversity, but to date, no such surveys have been conducted in the third potential glacial refuge area, the Apennine peninsula. We report here the phylogeographical analysis of 115 greater mouse-eared bats (Myotis myotis) sampled throughout Italy, and show that 15 of the 18 different haplotypes found in the mitochondrial control region of these bats were unique to the Apennine peninsula. Colonies within this region also showed substantial genetic structure at both mitochondrial (Phi(ST) = 0.47, P < 0.001) and nuclear markers (F-ST = 0.039, P < 0.001). Based on a comprehensive survey of 575 bats from Europe, these genetic markers further indicate that central Italian populations of M. myotis are more closely related to Greek samples from across the Adriatic Sea, than to other Italian bats. Mouse-eared bat populations from the Apennine peninsula thus represent a complex mixture of several endemic lineages, which evolved in situ, with others that colonized this region more recently along an Adriatic route. Our broad survey also confirms that the Alps represent a relatively impermeable barrier to gene flow for Apennine lineages, even for vagile animals such as bats. These results underline the conservation value of bats from this region and the need to include the Apennine peninsula in phylogeographical surveys in order to provide a more accurate view of the evolution of bats in Europe.
ABSTRACT Liposomal amphotericin B was immunosuppressive on target cell lysis in vitro and on protection mediated by cytotoxic CD8 T cells in murine listeriosis. When dosages usually used for therapy in humans were compared, the immunosuppressive effect of 5 mg of liposomal amphotericin B/kg of body weight/day was similar to that of standard amphotericin B at 1 mg/kg/day, but a dosage of liposomal amphotericin B of 1 mg/kg/day was not suppressive in vivo.
Amphotericin B is frequently used for the treatment of fungal infections of immunocompromised individuals. Whereas immunomodulatory side effects of this agent are known, the influence of amphotericin B was studied in the model of murine Listeria monocytogenes infection. Treatment of L. monocytogenes-immune mice with a nontoxic dose of amphotericin B (0.75 mg/kg) reduced antilisterial protection by 4-5 orders of magnitude, while it had no significant effect on natural immunity against L. monocytogenes in naive mice. Treatment of mice with amphotericin B also abolished the protection mediated by transfer of an L. monocytogenes-specific CD8 T cell line. Furthermore, in vitro analysis showed that amphotericin B impaired target cell lysis and interferon-gamma production by peptide-specific CD8 T-cell lines and antigen presentation by L. monocytogenes-infected macrophagelike cells, These data indicate that amphotericin B has a strong suppressive effect on the function of CD8 T cells in vitro and in vivo.