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Citizen science is an approach that has become increasingly popular in recent years. Despite this growing popularity, there still is widespread scepticism in the academic world about the validity and quality of data from citizen science projects. And although there might be great potential, citizen science is a rarely used approach in the field of bioacoustics. To better understand the possibilities, but also the limitations, we here evaluated data generated in a citizen science project on nightingale song as a case study. We analysed the quantity and quality of song recordings made in a non-standardized way with a smartphone app by citizen scientists and the standardized recordings made with professional equipment by academic researchers. We made comparisons between the recordings of the two approaches and among the user types of the app to gain insights into the temporal recording patterns, the quantity and quality of the data. To compare the deviation of the acoustic parameters in the recordings with smartphones and professional devices from the original song recordings, we conducted a playback test. Our results showed that depending on the user group, citizen scientists produced many to a lot of recordings of valid quality for further bioacoustic research. Differences between the recordings provided by the citizen and the expert group were mainly caused by the technical quality of the devices used—and to a lesser extent by the citizen scientists themselves. Especially when differences in spectral parameters are to be investigated, our results demonstrate that the use of the same high-quality recording devices and calibrated external microphones would most likely improve data quality. We conclude that many bioacoustic research questions may be carried out with the recordings of citizen scientists. We want to encourage academic researchers to get more involved in participatory projects to harness the potential of citizen science—and to share scientific curiosity and discoveries more directly with society.

Acoustic pattern recognition methods introduce new perspectives for species identification, biodiversity monitoring and data validation in citizen science but are rarely evaluated in real world scenarios. In this case study we analysed the performance of a machine learning algorithm for automated bird identification to reliably identify common nightingales ( Luscinia megarhynchos ) in field recordings taken by users of the smartphone app Naturblick . We found that the performance of the automated identification tool was overall robust in our selected recordings. Although most of the recordings had a relatively low confidence score, a large proportion of the recordings were identified correctly.

The Drosophila proteins Neuroligin (Nlg1) and Neurexin (Nrx-1) form a trans-synaptic complex that regulates synapse formation at the neuromuscular junction. Here the authors show that Syd-1, also known to regulate active zone formation, interacts with presynaptic Nrx-1, promoting synaptic clustering and immobilization of Nrx-1, and subsequent glutamate receptor incorporation. Synapse formation and maturation requires bidirectional communication across the synaptic cleft. The trans-synaptic Neurexin-Neuroligin complex can bridge this cleft, and severe synapse assembly deficits are found in Drosophila melanogaster neuroligin (Nlg1 , dnlg1) and neurexin ( Nrx-1 , dnrx ) mutants. We show that the presynaptic active zone protein Syd-1 interacts with Nrx-1 to control synapse formation at the Drosophila neuromuscular junction. Mutants in Syd-1 ( RhoGAP100F , dsyd-1 ), Nrx-1 and Nlg1 shared active zone cytomatrix defects, which were nonadditive. Syd-1 and Nrx-1 formed a complex in vivo , and Syd-1 was important for synaptic clustering and immobilization of Nrx-1. Consequently, postsynaptic clustering of Nlg1 was affected in Syd-1 mutants, and in vivo glutamate receptor incorporation was changed in Syd-1 , Nrx-1 and Nlg1 mutants. S tabilization of nascent Syd-1–Liprin-α (DLiprin-α) clusters, important to initialize active zone formation, was Nlg1 dependent. Thus, cooperation between Syd-1 and Nrx-1–Nlg1 seems to orchestrate early assembly processes between pre- and postsynaptic membranes, promoting avidity of newly forming synaptic scaffolds.

The subunit composition of postsynaptic non–NMDA-type glutamate receptors (GluRs) determines the function and trafficking of the receptor. Changes in GluR composition have been implicated in the homeostasis of neuronal excitability and synaptic plasticity underlying learning. Here, we imaged GluRs in vivo during the formation of new postsynaptic densities (PSDs) at Drosophila neuromuscular junctions coexpressing GluRIIA and GluRIIB subunits. GluR composition was independently regulated at directly neighboring PSDs on a submicron scale. Immature PSDs typically had large amounts of GluRIIA and small amounts of GluRIIB. During subsequent PSD maturation, however, the GluRIIA/GluRIIB composition changed and became more balanced. Reducing presynaptic glutamate release increased GluRIIA, but decreased GluRIIB incorporation. Moreover, the maturation of GluR composition correlated in a site-specific manner with the level of Bruchpilot, an active zone protein that is essential for mature glutamate release. Thus, we show that an activity-dependent, site-specific control of GluR composition can contribute to match pre- and postsynaptic assembly.

|Objectives. Most developmental processes are under the control of small regulatory RNAs called microRNAs (miRNAs). We hypothesize that different fetal developmental processes might be reflected by extracellular miRNAs in maternal plasma and may be utilized as biomarkers for the noninvasive prenatal diagnosis of chromosomal aneuploidies. In this proof-of-concept study, we report on the identification of extracellular miRNAs in maternal plasma of Down syndrome (DS) pregnancies. Methods. Using high-throughput quantitative PCR (HT-qPCR), 1043 miRNAs were investigated in maternal plasma via comparison of seven DS pregnancies with age and fetal sex matched controls. Results. Six hundred and ninety-five miRNAs were identified. Thirty-six significantly differentially expressed mature miRNAs were identified as potential biomarkers. Hierarchical cluster analysis of these miRNAs resulted in the clear discrimination of DS from euploid pregnancies. Gene targets of the differentially expressed miRNAs were enriched in signaling pathways such as mucin type-O-glycans, ECM-receptor interactions, TGF-beta, and endocytosis, which have been previously associated with DS. Conclusions. miRNAs are promising and stable biomarkers for a broad range of diseases and may allow a reliable, cost-efficient diagnostic tool for the noninvasive prenatal diagnosis of DS.

In the project \"Stadtnatur entdecken\" (discovering nature in the city) a multidisciplinary team of specialists in biology, informatics, urban ecology and social sciences is looking into how to effectively communicate educational content on environmental topics to young adults and to allow them to contribute as citizen scientists. The mobile app \"Naturblick\" presents on experience of nature in an urban setting. Several tools are combined in the app that allows users to identify species. The team developed auditory and visual pattern recognition tools that will automatically identify sound recordings and photographs and multi-access identification keys for flora and fauna. There is a map function that will help explore nature in the users’ immediate vicinity in Berlin, Germany, highlighting the diversity of species to be found. Users are able to share their observations and records. The project is designed to involve user participation and continuous improvement based on user feedback of both the content and technology.