Migratory bats are sensitive to magnetic inclination changes during the compass calibration period

The Earth's magnetic field is used as a navigational cue by many animals. For mammals, however, there are few data to show that navigation ability relies on sensing the natural magnetic field. In night-time migrating bats, experiments demonstrating a role for the solar azimuth at sunset in the calibration of the orientation system suggest that the magnetic field is a candidate for their compass. Here, we investigated how an altered magnetic field at sunset changes the nocturnal orientation of the bat Pipistrellus pygmaeus. We exposed bats to either the natural magnetic field, a horizontally shifted field (120°), or the same shifted field combined with a reversal of the natural value of inclination (70° to -70°). We later released the bats and found that the take-off orientation differed among all treatments. Bats that were exposed to the 120° shift were unimodally oriented northwards in contrast to controls which exhibited a bimodal north-south distribution. Surprisingly, the orientation of bats exposed to both a 120° shift and reverse inclination was indistinguishable from a uniform distribution. These results suggest that these migratory bats calibrate the magnetic field at sunset, and for the first time, they show that bats are sensitive to the angle of magnetic inclination.</p

Early phase of plasticity-related gene regulation and SRF dependent transcription in the hippocampus

Hippocampal organotypic cultures are a highly reliable in vitro model for studying neuroplasticity: in this paper, we analyze the early phase of the transcriptional response induced by a 20 \ub5M gabazine treatment (GabT), a GABA-Ar antagonist, by using Affymetrix oligonucleotide microarray, RT-PCR based time-course and chromatin-immuno-precipitation. The transcriptome profiling revealed that the pool of genes up-regulated by GabT, besides being strongly related to the regulation of growth and synaptic transmission, is also endowed with neuro-protective and pro-survival properties. By using RT-PCR, we quantified a time-course of the transient expression for 33 of the highest up-regulated genes, with an average sampling rate of 10 minutes and covering the time interval [10 3690] minutes. The cluster analysis of the time-course disclosed the existence of three different dynamical patterns, one of which proved, in a statistical analysis based on results from previous works, to be significantly related with SRF-dependent regulation (p-value<0.05). The chromatin immunoprecipitation (chip) assay confirmed the rich presence of working CArG boxes in the genes belonging to the latter dynamical pattern and therefore validated the statistical analysis. Furthermore, an in silico analysis of the promoters revealed the presence of additional conserved CArG boxes upstream of the genes Nr4a1 and Rgs2. The chip assay confirmed a significant SRF signal in the Nr4a1 CArG box but not in the Rgs2 CArG box

A microarray analysis of developmentally regulated genes during macronuclear differentiation in the stichotrichous ciliate Stylonychia lemnae

Paschka AG, Horejschi V, Jonsson F, et al. A microarray analysis of developmentally regulated genes during macronuclear differentiation in the stichotrichous ciliate Stylonychia lemnae. Gene. 2005;359:81-90

Alteration in the gene expression pattern of primary monocytes after adhesion to endothelial cells

Monocytes originate from precursors made in the bone and remain in the circulation for nearly 24 h. Much effort has been done to identify the molecules regulating transendothelial migration of monocytes during inflammatory conditions. In contrast, considerably less is known about the process of constitutive monocyte emigration although nearly 340 million monocytes leave the circulation each day in healthy individuals. Previous studies indicated that chemokines were up-regulated in monocytes cocultured with endothelial cells that induce the retraction of the latter cell type, thereby increasing vascular permeability. Thus, we hypothesized that the utilities required for efficient constitutive monocyte extravasation are generated by monocytes themselves because of adhesion to naïve endothelial cells. To test this hypothesis, cDNA microarray analysis was performed to determine the changes in the gene expression pattern of primary monocytes that have been attached to endothelial cells compared with monocytes that were held in suspension, and we were able to identify three major groups of genes. The first group includes genes such as matrix metalloproteinase 1, monocyte chemoattractant protein 1, and tissue transglutaminase 2, which are likely required for monocyte extravasation. The second group consists of genes that are expressed in phagocytes such as caveolin-1 and CD74. Finally, the third group comprises genes that are expressed in cells of endothelial tissue and cartilage including E-selectin, fibronectin-1, matrix Gla protein, and aggrecanase-2. In summary, we conclude that adhesion of peripheral blood monocytes to naïve endothelial cells has two effects: mandatory extravasation-specific genes are regulated, and the differentiation program of monocytes is initiated