Project description:Usutu virus (USUV) is a neurotropic flavivirus closely related to West Nile virus (WNV). Its enzootic cycle mainly involves mosquitoes and birds. Human infection can occur with occasional, but sometimes severe, neurological complications. Since its emergence and spread in Europe over the last two decades, USUV has been linked to significant avian outbreaks, especially among Passeriformes, including European blackbirds (Turdus merula). Strikingly, no in vivo avian model exists so far to study this arbovirus. The domestic canary (Serinus canaria) is a passerine, which is considered as a highly susceptible model of infection by WNV. Here, we experimentally challenged domestic canaries with two different doses of USUV. All inoculated birds presented detectable amounts of viral RNA in the blood and RNA shedding via feathers and droppings during the early stages of the infection, as determined by RT-qPCR. Mortality occurred in both infected groups (1/5 and 2/5, respectively) and was not necessarily correlated to a pure neurological disease. Subsequent analyses of samples from dead birds showed histopathological changes and virus tropism mimicking those reported in naturally infected birds. A robust seroconversion followed the infection in almost all the surviving canaries. Altogether, these results demonstrate that domestic canaries constitute an interesting experimental model for the study of USUV pathogenesis and transmission.
Project description:Song production in songbirds is controlled by a network of nuclei distributed across several brain regions, which drives respiratory and vocal motor systems to generate sound. We built a model for birdsong production, whose variables are the average activities of different neural populations within these nuclei of the song system. We focus on the predictions of respiratory patterns of song, because these can be easily measured and therefore provide a validation for the model. We test the hypothesis that it is possible to construct a model in which (1) the activity of an expiratory related (ER) neural population fits the observed pressure patterns used by canaries during singing, and (2) a higher forebrain neural population, HVC, is sparsely active, simultaneously with significant motor instances of the pressure patterns. We show that in order to achieve these two requirements, the ER neural population needs to receive two inputs: a direct one, and its copy after being processed by other areas of the song system. The model is capable of reproducing the measured respiratory patterns and makes specific predictions on the timing of HVC activity during their production. These results suggest that vocal production is controlled by a circular network rather than by a simple top-down architecture.
Project description:Within the overall project, we performed a set of microarrays to validate RNAseq data. In this data set, we compare the expression data of song nuclei to the optical tectrum dissected from adult canaries housed at long day cycles to identify nuclei specific genes.
Project description:Male song in songbirds is a critical and elaborate signal for mate attraction. In many species female listeners respond to male song both behaviorally and physiologically (e.g. copulation solicitation displays and production of the immediate early gene ZENK in auditory regions). It is becoming increasingly well known that females in many species also sing. However, in common lab species, such as canaries (Serinus canaria), female song is limited and has been primarily studied in the context of administering of exogenous testosterone (T) to increase song rate and length. In this study we addressed to what extent female canary songs are masculinized by the administration of exogenous T based on the behavioral and physiological responses of avian receivers. Specifically, are T induced female songs sufficient to elicit courtship behaviors and auditory ZENK expression in female listeners? We found that female songs after 3 weeks of exogenous T were significantly longer and more complex than female songs after 12 weeks of exogenous T. Additionally, we found that playback of 3-week T song significantly increased sexual response behaviors and the expression of ZENK in the auditory brain regions of female listeners. Finally, we conclude that extended periods of T do not necessarily maintain the masculinization of female song.
Project description:Most studies on sexual selection focus on male characteristics such as male song in songbirds. Yet female vocalizations in songbirds are growing in interest among behavioural and evolutionary biologists because these vocalizations can reveal the female's preferences for male traits and may affect male display. This study was designed to test whether male song performance influences the different female signals in the domestic canary (Serinus canaria). Female canaries were exposed to three types of song performance, differing in the repetition rate of sexy syllables. This experiment demonstrates that female birds are engaged in multimodal communication during sexual interaction. The results support the copulation solicitation hypothesis for female-specific trills: these trills were positively correlated and had a similar pattern to the copulation solicitation displays; responses were higher to the songs with higher performance and responses decreased with the repetition of the stimulation. Also, we observed a sensitization effect with the repetition of the song of the highest performance for the simple calls. Simple trills and other calls were more frequent during the broadcast of canary songs compared with the heterospecific control songs. The differential use of female signals in response to different song performance reveals a highly differentiated female signalling system which is discussed in light of the role of female traits to understand sexual selection in a broader perspective.
Project description:Within the overall project, we performed a set of microarrays to validate RNAseq data (submitted to EBI: PRJEB4463). In this data set, we compare the expression data of song nuclei to the optical tectrum dissected from adult canaries housed at long day cycles to identify nuclei specific genes. 18 total S. canaria samples were analyzed, 6 HVC samples, 5 RA samles and 7 Entopallium samples. The differential expression was analyzed using the group-wise exhaustive analysis with False Discovery Rate set to zero and 10-significant probe minimum coverage, HVc/RA compared to entopallium samples. ChipInspector carries out significance analysis on the single probe level (directly generated from the CEL files). Thus, normalized probe set level data for individual Sample records are not available. Processed data files containing transcripts and the fold changes are available on Series record.