Dezember 2024 – Forschungsstiftung

Microclimate Buffering within Alpine Landscapes

Microclimate Buffering within Alpine Landscapes: Linking Ecophysiology, Behavioral Plasticity & Microhabitat Selection of Alpine Avifauna in a Changing Climate

Mountain ecosystems are among the regions most susceptible to temperature warming, and species adapted to alpine ecosystems are predicted to face local extinctions via physiological and/or behavioral intolerance to rapid increases in temperature. However, information is lacking regarding the ability of alpine birds to adapt both behaviorally and physiologically to rapidly warming temperatures.

Our research project leverages state-of-the-art advances in thermal imaging, GPS tracking, and animal biologging technologies to examine how alpine birds exhibit behavioral plasticity to temperature warming via selection of microhabitats that provide cool microclimates and buffering from high temperatures. We are focusing on two species predicted to respond differently to warming temperatures: the Alpine Rock Ptarmigan (cold adapted) and Rock Partridge (warm adapted). The ultimate goal of the project is to provide concrete recommendations for managing microhabitat structures within alpine landscapes that are predicted to provide microclimatic buffering and refugia from thermal warming.

Funding from the UniBern Forschungsstiftung allowed us to purchase a professional thermal imaging drone (DJI Mavic 3T) that maps ground surface temperatures at extremely fine resolutions relevant to the biology of our focal species (<10 cm). Funding also covered associated accessories that allowed efficient fieldwork in challenging alpine landscapes, including a professional base station that provided real-time kinetic (RTK) connectivity to the drone and centimeter-level spatial accuracy while mapping. During the summer of 2024, we successfully deployed the drone during the summer breeding season (June – August) within territories of our two target species. This work resulted in the creation of over 250 high resolution thermal maps of ground surface temperature that will be aligned with fine-scale movement data generated by GPS tags mounted on captured birds to understand how the two species are selecting for different thermal regimes. The drone work directly supported the MSc thesis of Luca Robbi, who conducted the fieldwork and mastered skills in drone piloting procedures, land cover mapping, and data management that will be of fundamental value for him when securing an internship and eventual full-time employment in the environmental sector. The drone will be integral to completing the project, which is planned to continue for two more years in 2025 – 2026.

Dr. Ian J. Ausprey
Institute of Ecology & Evolution
Division of Conservation Biology

An example of a completed land surface temperature map produced by stitching together several hundred drone photos. The dark points are movement coordinates for a Rock Ptarmigan carrying a GPS positioning tag that were collected concurrently with the temperature map. By superimposing the two datasets, we will be able to measure the exact land surface temperatures being experienced by alpine birds at extremely high spatial resolutions (< 10 cm).

Systematic Exploration of Novel Chemical Spaces for New Antimicrobial Agents

Our group is interested in the synthesis, characterisation and biological evaluation of transition metal complexes as antimicrobials (www.thefreilab.com). We prepare large libraries of hundreds of compounds and evaluate their antibacterial properties. While these assays can be read-out by eye, this is an error-prone and low-throughput procedure. With the TECAN Infinite M Nano (Figure 1) acquire with support from the UniBern Forschungsstiftungs grant we can read out up to 96 compounds (Figure 2), with high precision in a fraction of the time. However, our use of the plate-reader is not limited to antimicrobial assays. We also utilise it for haemolysis assays where we determine if a given compound has the (unwanted) capacity to destroy red blood cells (Figure 3).

Furthermore. we have also utilise the plate-reader for mode of action studies, utilising fluorescent dyes to e.g. quantify if bacterial membranes are destroyed. We also monitored 96 catalytic reactions performed by our compound library in real time over 12 h to compare the catalytic performance of 96 metal compounds at once (Figure 4).

Overall, the acquisition of this instrument has had rippling benefits throughout all areas of our research, and we keep finding novel ways to utilise it.

Dr. Angelo Frei
Departement für Chemie, Biochemie und Pharmazie

www.thefreilab.com

Evaluation of the parasympathetic tone activity (PTA)™ index as biomarker of nociception in pigs

One of the main aims of our group is to research on nociceptive processes, diagnostic strategies and treatment approaches in animals.

A major challenge for veterinarians is to correctly evaluate nociception during general anaesthesia. In this context, novel strategies should be investigated.

With the financial support of the UniBern Forschungsstiftung we were able to acquire the parasympathetic tone activity (PTA)™ monitor (Fig.1). Through the analysis of the activity of the parasympathetic nervous system (heart rate variability evaluation), it provides the anaesthesiologists with an index of nociception (PTA index), expressed on a scale between 0 and 100: values close to 100 indicate absence of nociception, while values below 50 suggest presence of nociception.

The present project aims at assessing the reliability of the PTA in pigs, species largely used for experimental and translational studies. Data were collected before, during, and after the application of various nociceptive stimuli, while the pigs were under propofol-based anaesthesia. Data collection has been completed, and analysis is ongoing.

The PTA index has the potential to serve as an additional tool for evaluating the nociceptive/anti-nociceptive status of animals under general anaesthesia.

Dr. med. vet. Alessandro Mirra
Anaesthesiology and Pain Therapy Section
Vetsuisse Faculty

Robustness and Individuality in Organ Growth Control of C. elegans

Correctly sized body parts are crucial for organismal function. For example, small discrepancies in limb length severely obstruct motility, and overgrowth of cardiac muscle is a prevalent cause of heart failure. The growth of different cells and organs must therefore be tightly coordinated to prevent that even small differences in growth rates amplify to large differences in size during development. How growth signals are propagated from cell to cell, and how organs integrate combinatorial signals from different tissues is a fundamental, yet poorly addressed question of high biomedical relevance. We address this question using quantitative live imaging experiments with the nematode worm C. elegans.

Specifically, we used strains expressing a green fluorescent protein in the pharynx of C. elegans and a red fluorescent protein in all cells of the body. Using a micro cultivation technique, we grew individual animals in small chambers that can be maintained on a fluorescent microscope over many days and the entire development of C. elegans. This technique allows us to precisely monitor the growth of the pharynx and the body size at high time resolution for individual animals and measure the heterogeneity in growth and size among individuals of an isogenic population. Our key finding is that there exists a molecular mechanism that coordinates the growth of the pharynx and the body, such that the relative proportions between the pharynx and the body length are very robust to even strong perturbations.

The “Nikon piezo stage” that we were able to acquire thanks to the UniBern Forschungsstiftungs’ grant, has become essential for our investigations. The piezo drive enables extremely rapid acquisition of three dimensional image stacks with minimal time delay between optical sections. This speed is crucial for our application, as the animals are not anesthetized inside the chambers and move rapidly. Thanks to the rapid acquisition, we can now effectively acquire large stacks of images and reconstruct 3-dimensional representations of the animals.

Prof. Dr. Benjamin Towbin
Institute of Cell Biology

https://izb.unibe.ch/

Reflection Microscope for characterization of collective mucociliary activity

Primary ciliary dyskinesia (PCD) is a rare hereditary disease impairing the ciliary activity and resulting in a variety of respiratory symptoms, such as neonatal respiratory distress in term-born infants, chronic rhino-sinusitis and persistent wet cough from the day of birth, and recurrent respiratory tract infections often resulting in later bronchiectasis. Mutations in more than 50 genes are known to cause defects in the structure and function of cilia. Abnormalities in the ciliary structure lead to ciliary dyskinesia, which results in an impairment of the mucociliary transport. Reduced mucociliary transport then leads to less efficient removal of respiratory pathogens from the airways. Due to the high number of potentially involved genes, the diagnosis of PCD is very challenging. There is no single gold standard test and a combination of methods has to be performed. Therefore, we would like to use computational high-speed video reflection microscopy (CRM) to assess the collective mucociliary activity in air-liquid interface (ALI) cell cultures of nasal epithelial cells derived from patients with suspicion of PCD. This approach has the potential to become the first diagnostic approach allowing to diagnose PCD in a highly accurate as well as automated and cost-effective way.

With the support of the Berne University Research Foundation we bought a reflection microscope to record the surface of ALI-cultured, differentiated cells of patients suspicious for PCD. The addition of a climate chamber furthermore enabled temperature control during experiments. The videos can be analyzed using our Cilialyzer software and we will investigate which parameters of the collective ciliary activity could discriminate reliably and sensitively between healthy and PCD. Furthermore, the microscope is used to test the potential of various drugs (e.g. cystic fibrosis modulator drugs) to improve ciliary activity and mucociliary transport in vitro.

PD Dr. Loretta Müller

Department for BioMedical Research, Lung Precision Medicine (LPM)
Pädiatrische Pulmonologie, Inselspital, Kinderklinik