Research

Project Details:
Many animals use colorations in antipredator strategies. Cryptic coloration conceals the animal on its natural substrate while bright aposematic coloration is paired with unpalatability, for example conveyed by toxins, and functions as warning signal. Geographic variation in coloration shades or patterns have been interpreted as local adaptations to the prevailing local substrates and predator classes. Yellow bellied toads are particularly exciting study objects since they present a cryptic grey-brown coloration in their dorsum, but a highly contrasting yellow-black pattern on their bellies. The toads also possess highly poisonous bombinatoxins in their skin and use a deimatic display, the so-called Unkenreflex, when a predator is close. We studied variation in the cryptic and aposematic coloration in three local populations in Southern Lower Saxony. We found the toads to be most cryptic dorsally on their local substrates, while the internal aposematic contrast on the belly remained constant. Furthermore we investigate whether the toads are able to change their dorsal coloration when placed on substrates of different colorations (darker and brighter substrates). In the next steps, we will analyze whether toads from different localities and substrates differ in their capacities of coloration plasticity and which genes show differential expression (e.g. genes involved in the production of melanin) while the animals adapt their cryptic coloration to their current substrate. Finally we will carry out predation experiments with clay model toads in the field to find out whether the adaptation of cryptic coloration to the local substrate helps to decrease the attack risk by predators.

Results:

Preißler KP, Rodríguez A, Pröhl H (2021) Evidence for coloration plasticity in the yellow-bellied toad, Bombina variegata. Ecology and Evolution, 11: 17557-17567. https://doi.org/10.1002/ece3.8391

Cooperation Partners:

Kathleen Preißler, TU Braunschweig

Project Details:
Weiterentwicklung bioinformatischer Algorithmen für Meta-Analysen und Netzwerk-Meta-Analysen basierend auf hoch-dimensionalen Daten aus Transkriptom-, Proteom- und anderen Omics-Experimenten.

Results:

https://onlinelibrary.wiley.com/doi/abs/10.1002/jrsm.1337

https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-018-4914-4

Funding: Bundesministerium für Umwelt, Naturschutz, Bau und Reaktorsicherheit, 856.344 EUR

Project Details:
Aim of the project is to study the impact of synthetic generated marine vibrator (MV) signals on baleen whales. The Arctic area is under constant change from anthropogenic utilisation and climatic alterations. These alterations have implications for the animal living in the area. Seismic airgun array explorations and other oil exploration activities are predicted to increase around Iceland in the near future.
The field work will be conducted in Northeast Iceland off the town Husavik. Here many species of baleen whales are found regularly throughout the summer months in Skjalfandi bay. The blue whale (Balaenoptera musculus) is the iconic cetacean off Husavik. Other baleen whales in the area will also be used as target species, such as humpback whales (Megaptera novaeangliae) or minke whales (Balaenoptera acutorostrata). All species found off Husavik are also present in Antarctica. Thus, studies of the impact of sound on whales off Husavik are also relevant for Antarctic environmental issues.
The reactions of several baleen whale species on synthetic generated marine vibrator (MV) signals, will be examined on their feeding grounds. The baleen whales will be tagged using acoustic tags. Low frequency sound will be projected via an underwater loud speaker (Argotec sound source). These tags will be able to record sound levels at the animal, vocalization as well as fine scale variations of movements and environmental parameter. By these techniques we will be able to compare swim direction, swim speed, dive profile, behaviour patterns and vocalization before and after sound emission. At the same time, visual observations will be conducted and any behavioural changes will be noticed.

Results:

Sound is the sensory cue that travels farthest through the ocean. It is used by the marine fauna to interpret the marine environment and for intra- and inter-specific communication in marine animals, ranging from invertebrates to large whales. Previously pristine regions such as the Arctic are currently under rapid change driven by human exploitation and global warming. The Arctic is of key importance for many marine organisms, such as feeding blue whales. As intense sound emissions from e.g., oil and gas exploration may have large effects on marine mammals, it is important to look for alternative sound sources. The aim of the project is to study the reactions of blue whales to synthetically generated marine vibroseismic acoustic signals on their feeding grounds. The behaviour of blue whales was measured using combined acoustic and behavioural tags recording received sound level at the animal as well as their dive parameters. An underwater loudspeaker (Argotec sound source, SS-2) was used to expose animals to low- frequency sounds similar to those of Marine Vibrators (MVs), while behavioural responses were measured by the animal-borne tag. Additionally, visual observations and acoustic buoys were used to record further behavioural responses. The source level of the loudspeaker was found to be 180-188 dB re 1 μPa at 1 m, by analysing measured received levels at different ranges during the Controlled Exposure Experiments. The maximum distance to the loudspeaker where behavioural changes, including acoustic responses, are expected to occur, following the NMFS (NMFS, 2022) marine mammal behavioural response criterion of 120 dB re 1 μPa, was modelled at a range up to 11.1 km. During the sound exposure changes in blue whale behaviour were found in time spent at the surface (< 2 m water depth) for dive and post-dive duration, compared to the baseline behaviour. Tagged animals were continuously foraging before exposure, but stopped briefly foraging during vibroseismic playback, displaying only non- foraging dives activities. We observed that blue whales changed their signal?s amplitude, duration, repetition rate, and frequency, which can be interpreted as a compensatory mechanism for increased ambient noise. This ability to overcome masking noise by adjusting their vocalisation is crucial for communicating despite the presence of vibroseismic signals. These reactions occurred for whales within the 11 km behaviour response range. Despite the lack of direct comparative studies, it can be assumed that the reactions of the blue whales are probably less severe for MVs than other sound sources used for oil and gas exploration (such as airguns), however our study emphasize the need for cautionary approaches when using MVs at closer ranges from blue whales.

Funding: DFG, 199.050 EUR

Project Details:
The role of NMDA receptors in neuronal plasticity is well established. However, their role in intracellular voltage-signaling and sensory processing is less well characterized, yet they are implicated in amplifying action potential firing rates. To understand the cellular basis for this NMDA dependent amplification of firing rate, its influence on sensory processing and the carried sensory information we will perform in vivo and in vitro recordings of neurons in the dorsal nucleus of the lateral lemniscus (DNLL) - an auditory brainstem structure important for binaural hearing. We will determine the synaptic interactions of excitation and inhibition with NMDA receptor conductances to understand their contributions to intracellular voltage-signaling in vitro. Using in vivo pharmacology we will answer what impact NMDA receptors have on sound driven firing rates. Thereby, the DNLL serves on the one hand as a read out nucleus where the impact of NMDA receptors on relaying binaural information will be quantified. On the other hand we will assay in vivo the direct binaural interactions at the level of the DNLL to understand the influence of NMDA receptors on interactions between inhibition and excitation. We hypothesize that these interactions might be crucial in terminating a long lasting inhibition that is regarded as a cellular correlate for the suppression of sound sources during echoes.

Results:

Felmy F.: The nuclei of the lateral lemniscus. The Oxford Handbook of auditory brainstem. Edited by Karl Kandler. 2019

 

Kladisios N., Fischer L., Felmy F.: Minimal Number of Required Inputs for Temporally Precise Action Potential Generation in Auditory Brainstem Nuclei. Front Cell Neurosci. 2020 Nov 5;14:592213

 

Siveke I., Lingner A., Ammer J.J., Gleiss S.A., Grothe B., Felmy F.: A Temporal Filter for Binaural Hearing Is Dynamically Adjusted by Sound Pressure Level. Front Neural Circuits. 2019 Feb 13; 13:8.

 

Siveke I., Ammer J.J., Gleiss S.A., Grothe B., Leibold C., Felmy F.: Electrogenic N-methyl-D-aspartate receptor signaling enhances binaural responses in the adult brainstem. European Journal of Neuroscience, 2018, 47, 858-865

Funding: DFG, 248.138 EUR

Project Details:
Das Ziel dieser Studie ist die Aufklärung der genetischen Mechanismen, die die Lockenbildung im Haarkleid beeinflussen. Auf der Grundlage der bisherigen Untersuchungen im Rahmen dieses DFG-Projektes konnte gezeigt werden, dass die Lockenbildung zwar durch einzelne Mutation initiiert wird, jedoch weitere genetische Prozesse die Struktur und Stärke der Locken beeinflussen. Im weiteren Verlauf dieser Studien soll nun anhand des Tiermodels Schwein vergleichend zum Pferd untersucht werden, welche Gene in der Haarentwicklung interagieren und jahreszeitlich- und temperaturabhängige Unterschiede verursachen. Dabei sollen durch Haarprobennahmen in einer einheitlichen Umgebung, in monatlichen Intervallen und über die Generationen hinweg Gen-Expressionsunterschiede im Haaren mittels Next Generation Sequencing Technologie analysiert werden. Das Mangaliza Wollschwein stellt hierfür durch sein im Vergleich zum Pferd kürzeres Generationsintervall und die höhere Nachkommenzahl ein geeignetes Model zur Verifizierung dar. Diese Herangehensweise bietet einen ganz neuen Ansatz in der Erforschung der Haarentwicklung und soll damit Mechanismen erklären, die tierartübergreifend für die Ausprägung eines lockigen Haares entscheidend sind.
Darüber hinaus soll durch die Aufklärung der genetischen Variante für die charakteristische und sehr rassetypische Lockenbildung beim Mangaliza Wollschwein einen Beitrag zur Arterhaltung dieser bedrohten Rasse geleistet werden.

Results:

https://www.frontiersin.org/articles/10.3389/fgene.2023.1184015/full

Project Details:
The gastrointestinal tract is constantly exposed to considerable challenges. As a consequence of bacterial and dietary antigens found in the lumen, the intestine displays a low-grade physiological inflammation. Under pathological conditions, such as the inflammatory bowel disease (IBD), the intestinal mucosa is infiltrated by inflammatory cells including neutrophils, macrophages, and lymphocytes. The inflammatory cells homing to the intestinal mucosa come in close proximity to the intestinal epithelial cell (IEC) layer, and may be involved in induction of the functional impairment of IECs. Three essential mechanisms may contribute to the induction of this state: (i) soluble mediators secreted by inflammatory cells, (ii) direct adhesion and signaling molecules expressed on the surface of immune cells and epithelial cells and (iii) cytoplasmic exchange of specific signals between the inflammatory cells and IECs via gap junction (GJ) channels. Gap junctions (GJ) are clusters of intercellular channels, which allow a direct exchange of ions and signalling metabolites of low molecular weight (less than 2 kDa) between adjacent cells. Gap junction channels span the plasma membranes of two adjacent cells and are composed of members of highly homologous family of proteins known collectively as connexins (Cx), which are named according to their theoretical molecular weight. Connexin 43 is the most abundant and widely spread connexin in human body which has been intensively studied for its role in inflammatory conditions. Our recent study (Cross-talk between intestinal epithelial cells and immune cells in inflammatory bowel disease. Al-Ghadban S, Kaissi S, Homaidan FR, Naim HY, El-Sabban ME. Sci Rep. 2016 Jul 15;6:29783. doi: 10.1038/srep29783.) and preliminary work have shown that IECs and immune cells (macrophages) are expressing Cx26 and Cx43 proteins and are able to create functional homo- and hetero-cellular GJs.
This project aims to study the expression and regulation of Cx43 in intestinal epithelial cells (IECs) under normal and inflammatory conditions. The IECs to be utilized in this proposal are Caco-2 cells, which is a colorectal adenocarcinoma cell line widely used as models of intestinal transport and in pathology including inflammation. Moreover, post-biosynthetic assembly into functional homo- or heterotypic connexons and their trafficking to the plasma membrane will be investigated. Here special interest would be on analysing the mode of interaction of Cxs with cellular membranes specifically caveolin-rich membrane domains. Additionally, since important aspect of this proposal is to study the involvement of gap junction dependent cell-to-cell communication in the pathobiology of IBD, we will analyse whether the inflammatory reactions related to the induction of IBD have an effect on gap junction coupling and all above-mentioned processes. These data would be essential for understanding the physiological role of Cxs in IECs in more details and would shed more light onto possible changes in their function that happen upon IBD development and contribute to the progression of the disease.

Cooperation Partners:

Prof. Dr. Marwan El-Sabban, Medical Faculty, American University of Beirut, Libanon

Funding: Bundesinstitut für Risikobewertung, Berlin

Project Details:
The project VetCAb (Veterinary Consumption of Antibiotics) is a research project that is carried out to describe the use of antibiotics in farm animals in Germany. In 2007 and 2008 the project was conducted as a feasibility study and subsequently in 2011 a pilot study in a cross-sectional approach. The pilot study not only documented the consumption of antibiotics based on of individual farm information, but also directly related it to the livestock, so that a risk assessment can be realized. This defined a status quo for Germany, which made it possible to determine measures to reduce the use of antibiotics in farm animals.

Building on this, the VetCAb-Sentinel project is continued from 2013 as a longitudinal study with ongoing participant recruitment and data collection. The aim of the study is to evaluate how often the animals are treated with antibiotics during a defined period of time based on the treatment frequency (TF), i.e. # treated animals x # treatment days / # animals per farm. In addition, the study will, among other things, investigate whether regions or farm sizes differ with regard to the use of antibiotics and which classes of active substances are used in German livestock farming. VetCAb-Sentinel thus forms the basis of a scientific risk assessment, which, according to the DART (Deutsche Antibiotika Resistenzstrategie), makes a significant contribution to the reduction of antibiotic resistance.

https://ibei.tiho-hannover.de/vetcab

Results:

https://ibei.tiho-hannover.de/vetcab/

https://ibei.tiho-hannover.de/vetcab/pages/41

Project Details:
Ein unspezifisches chronisches Krankheitsgeschehen wurde mit einer Toxikoinfektion mit Clostridium botulinum (sog. viszeraler/chronischer Botulismus) in Verbindung gebracht. Unter anderem wurde von typischen Lahmheitssymptomen berichtet. In einer Fall-Kontroll-Studie konnte ein Zusammenhang zwischen dem chronischen Krankheitsgeschehen und Clostridium botulinum nicht nachgewiesen werden. Chronisch kranke Tiere aus Kontroll- und Fallbetrieben waren aber vermehrt lahm, wobei die Lahmheit überwiegend durch Erkrankung an den Klauen zustande kam. In vorliegendem Projekt wird untersucht, ob sich lahme Kühe aus Kontroll- und Fallbetrieben hinsichtlich der Diagnosen an den Klauen unterscheiden. In einer Risikofaktorenanalyse wurden weiterhin verschiedene Faktoren aus Haltung, Fütterung und Management auf mögliche Beziehungen zur Anzahl der Klauendiagnosen pro Tier untersucht.

Cooperation Partners:

Vereinigte Informationssysteme Tierhaltung w.V.(vit)

Funding: 5.000 EUR

Project Details:
Die Tierärztliche Hochschule Hannover hat von der Landwirtschaftlich-Gärtnerischen Fakultät der Humboldt-Universität Berlin eine Miniaturschweinepopulation (Mini-LEWE) übernommen, die sich vom Göttinger Miniaturschwein unterscheidet. Die Sauen, Eber und deren Nachkommen sollen regelmäßig klinisch und labordiagnostisch hinsichtlich verschiedener Gesundheitsparameter untersucht werden.
Die Anpaarungen werden entsprechend der Abstammung und genetischen Diversität optmimiert.
Die Mini-Lewe Population ist eine sehr wichtige Ressource für biomedizinische Versuche und eine erhaltungswürdie Population.
Die genetische Charakterisierung dieser Population erfolgt über populationsgenetische Kennzahlen zur Verwandtschaft, Inzuchtzunahme, effektive Populationsgröße, Inzuchtgrad und erwartete Inzuchtzunahme. Tiefergehende Analysen beruhen auf genomweiten Markersystemen, Beadchip-Genotypisierungen und Komplettgenomanalysen. Diese Daten geben Einblick in die genomische Architektur, genomische Verwandtschaft, genomische Diversität, Selektionssignaturen und ROH-Inseln.
Für spezifische Versuche werden Haplotypen von Genclustern und Gengruppen charakterisiert, um Tiere für Versuche auswählen zu können.

Results:

Reimer et al. 2018. Analysis of porcine body size variation using re-sequencing data of miniature and large pigs. BMC Genomics. 2018 Sep 19;19(1):687. doi: 10.1186/s12864-018-5009-y.

 

Schachler et al. Schätzung der genetischen Diversität der Mini-Lewe Zuchtpopulation und Einfluss von Inzucht auf Wurfgrößenmerkmale

Züchtungskunde, 91, (3) S. 227-245, 2019, ISSN 0044-5401

https://elib.tiho-hannover.de/receive/etd_mods_00000392?q=Richel

Cooperation Partners:

Prof. Dr. Rainer Blasczyk, MHH

Prof. Dr. Sabine Hammer, Vetmed Uni Wien

Project Details:
Unsere Hypothese ist, dass die endoskopische Besamung im Vergleich zur üblichen manuell-transvaginalen Besamung in den Gebärmutterkörper eine graduell verstärkte reaktive Entzündungsreaktion verursacht. Hierzu soll die reaktive Entzündungsreaktion des Endometriums (mit und ohne Samenübertragung) durch versuchsbegleitende Probengewinnung (Endometriumabstriche für bakteriologische und zytologische Untersuchungen, Uterusbiopsie zur pathohistologischen Untersuchung des Endometriums) verglichen werden.

Results:

doi: 10.1016/j.jevs.2020.103023. PMID: 32534786

Cooperation Partners:

Niedersächsisches Landgestüt Celle

Institut für Veterinär-Pathologie, Universität Leipzig