Research

Funding: VolkswagenStiftung, 6.569 EUR

Project Details:
The project aims to employ modern genetic tools to identify lemur populations of high conservation value to help prioritizing conservation efforts and to develop and implement conservation strategy for the most threatened and valuable lemur populations. The following points constitute the major project objectives: Objective 1: Identify and sample suitable populations of two lemur model species in the study region. Objective 2: Characterize the populations with regard to their genetic diversity, genetic uniqueness, and genetic connectivity to identify the site(s) with the highest conservation value and concern.

Cooperation Partners:

Dr. Fano Ratsoavina, Universität Antananarivo, Madagaskar

Jun.Prof. Helena Teixeira, PhD, Universität Montpellier, Frankreich

Funding: BMBF - DLR Projektträger, Teilprojekt aus dem BIODIVERSA Programm der EU, 301.195 EUR

Project Details:
The global biodiversity crisis that is affecting ecosystems worldwide is a major subject of concern and is expected to worsen with ongoing global changes. Climate change together with other anthropogenic factors will lead to the displacement of many favorable environments in the next decades owing to fast altitudinal and latitudinal shifts, with greatest predicted impacts in biodiversity hotspots. These shifts will lead to an increase in Habitat Loss and Fragmentation (HL&F), the main threats to Biodiversity worldwide. There is therefore a need to understand the consequences of HL&F, and to identify the barriers to gene flow at various spatial and temporal scales. We study HL&F in the context of past and future environmental changes, across taxa and regions. We use Madagascar as a model region and use comparative genomic analyses to infer generalizable critical features of ecological networks across various taxonomic and spatial scales. In particular, we identify barriers to gene flow based on genomic datasets and study the effects of forest fragmentation on the vegetation, and the abundance and parasite load of two mouse lemur and two rodent species.

Results:

Mercado-Malabet, F.; Ramsay, M.S.; Chell, C.; Andriatsitohaina, B.; Radespiel, U.; Lehman, S.M. (2024). Where the small things are: Modelling edge effects on mouse lemur population density and distribution in northwestern Madagascar. Am. J. Primatol., 87, e23621. https://doi.org/10.1002/ajp.23621.

 

Ramsay, M.S.; Sgarlata, G.; Barratt, C.D.; Salmona, J.; Andriatsitohaina, B.; Kiene, F.; Manzi, S.; Ramilison, M.L.; Rakotondravony, R.; Chikhi, L.; Lehman, S.M.; Radespiel, U. (2023): Effects of forest fragmentation on connectivity and genetic diversity in an endemic and an invasive rodent in northwestern Madagascar. Genes, 14(7), 1451. https://doi.org/10.3390/genes14071451.

 

Kiene, F.; Springer, A.; Andriatsitohaina, B.; Ramsay, M.S.; Rakotondravony, R.; Strube, C.*; Radespiel, U.* (2023): Filarial infections in lemurs: Evidence for a wide geographical distribution and low host specificity among lemur species. Am. J. Primatol., 85(2), e23458. DOI: 10.1002/ajp.23458 (*: joint senior authors)

 

Kiene, F.; Antriatsitohaina B.; Ramsay, M.S.; Rakotondravony, R.; Strube, C.*; Radespiel, U.* (2021): Habitat fragmentation and vegetation structure impact gastrointestinal parasites of small mammalian hosts in Madagascar. Ecology and Evolution 11, 6766-6788. Doi: 10.1002/ece3.7526.

 

Andriatsitohaina, B.; Romero-Mujalli, D.; Ramsay, M.S.; Kiene, F.; Rasoloharijaona, S.; Rakotondravony, R.; Lehman, S.M.; Radespiel, U. (2020): Effects of habitat edges on vegetation structure and the vulnerable golden-brown mouse lemur (Microcebus ravelobensis) in northwestern Madagascar. BMC Ecology 20, 69. https://doi.org/10.1186/s12898-020-00337-z.

Cooperation Partners:

Dr. Lounès Chikhi, IGC, Oeiras, Portugal

Prof. Olivier Mazet, Universität Toulouse, Frankreich

Dr. Guillaume Besnard, Universität Toulouse, Frankreich

Dr. Jordi Salmona, Universität Toulouse, Frankreich

Prof. Shawn Lehman, Universität Toronto, Canada

Dr. Romule Rakotondravony, Universität Mahajanga, Madagaskar

Prof. Solofonirina Rasoloharijaona, Universität Mahajanga, Madagaskar

Travis Steffens, PhD, University of Guelph, Canada; Planet Madagascar

Funding: DFG, 299.200 EUR

Project Details:
Marked climatic oscillations between glacial and interglacial periods had worldwide consequences for vegetation as well as animal population dynamics. The importance of these shallow-time (on geological and evolutionary timescales) geographic dynamics for shaping current biodiversity and biogeography patterns is increasingly stressed, although rarely analyzed in an innovative integrated manner. One of the necessary steps in order to understand the drivers of biodiversity is to synergize the efforts from various research fields by, for example, reconstructing the interplay between the degree and frequency of historic forest cover changes and demographic changes of forest-dependent organisms. This study aims to integrate validated records of vegetation and climate dynamics with inferred population dynamics to reconstruct the dynamics of forest landscapes and of populations of forest dwelling species over space and time in a primate model endemic to Madagascar. Madagascar developed a unique biodiversity during its long isolated history. Despite the long-lasting interest in the natural history of the island, much is still unknown about the biodiversity dynamics and long-term ecology of this continental island. This multidisciplinary project aims to integrate demographic inferences based on molecular datasets of mouse lemurs with validated high resolution vegetation dynamics based on paleoecological reconstructions obtained from the same study sites reaching back to the Last Glacial Maximum (LGM). To reach these goals, study sites in northwestern and northern Madagascar were visited for the joint collection of (paleo)ecological and population datasets and samples of mouse lemurs in direct vicinity to each other. For the paleoecological part sediment cores from lakes were drilled and complemented with samples of modern pollen rain and vegetation data. The sediment cores are subjected to temporal high-resolution pollen and charcoal analyses, radiocarbon dating and multivariate modelling of the vegetation and climate dynamics over time and space. The lemur samples are analyzed by applying RADSeq and NextSeq sequencing techniques on various subsets of samples. This study will contribute substantially to a deeper understanding of the evolutionary history and future prospects of lemur populations in view of ongoing habitat fragmentation and future climate change.

Results:

Montade, V.; Bremond, L.; Teixeira, H.; Kasper, T.; Daut, G.; Rasoamanana, E.; Pamavovolona, P.; Favier, C.; Arnaud, F., Radespiel, U.; Behling, H. (2024): Montane rain forest dynamics under changes in climate and human impact during the past millennia in northern Madagascar. R. Soc. Open Science, 11, 230930. https://doi.org/10.1098/rsos.230930.

 

Teixeira, H; Salmona, J; Arredondo, A.; Mourato, B; Manzi, S.; Rakotondravony, R.; Mazet, O; Chikhi, L.; Metzger, J; Radespiel, U. (2021): Impact of model assumptions on demographic inferences - the case study of two sympatric mouse lemurs in northwestern Madagascar. BMC Ecol. Evol. 21, 197. https://doi.org/10.1186/s12862-021-01929-z.

 

Teixeira, H.; Montade, V.; Salmona, J.; Metzger, J.; Bremond, L.; Kasper, T.; Daut, G.; Rouland, S.; Ranarilalatiana, S.; Rakotondravony, R.; Chikhi, L.; Behling, H.; Radespiel, U. (2021): Past environmental changes affected lemur population dynamics prior to human impact in Madagascar. Comm. Biol. 4, 1084. https://doi.org/10.1038/s42003-021-02620-1.

Cooperation Partners:

Jun.prof. Helena Teixeira, PhD Universität Montpellier, Frankreich

Prof. Hermann Behling, Universität Göttingen

Dr. Vincent Montade, Universität Montpellier, Frankreich

Dr. Lounès Chikhi, Universität Toulouse, Frankreich

Dr. Jordi Salmona, Universität Toulouse, Frankreich

Prof. Solofonirina Rasoloharijaona, Universität Mahajanga, Madagaskar

Dr. Romule Rakotondravony, Universität Mahajanga, Madagaskar

Project Details:
-

Cooperation Partners:

Zentrum für systemische Neurowissenschaften (ZSN), Hannover

Institut für Neuroimmunologie und Multiple-Sklerose-Forschung (IMSF) der Universitätsmedizin Göttingen, Göttingen

Funding: Bundesministerium für Gesundheit, 909.181 EUR

Project Details:
Mit Schreiben vom 15. Dezember 2015 hat die WHO unter der Referenznummer DEU-134 das Institut für Biometrie, Epidemiologie und Informationsverarbeitung an der Tierärztlichen Hochschule Hannover als "WHO Collaborating Centre for Rese-arch and Training for Health at the Human-Animal-Environment Interface" (WHO CC HAEI) designiert. Das WHO-Zentrum unterstützt auch weiterhin die WHO und ihre Mitgliedsstaaten. Die neue Designationperiode läuft nun für weitere zwei Jahre bis zum 17. Dezember 2023.
Der Aufgabenbereich (Terms of Reference, ToR) für das WHO CC HAEI wurde auf-grund der Umstrukturierung der AMR-Division neu formuliert. Seit dem 18. De-zember 2021 bis zum Ende der Designationperiode finden die Aufgabenbereiche TOR (i) und TOR (II) wie folgt Anwendung:
TOR (i) Unterstützung der WHO und ihrer Mitgliedsstaaten bei der Entwicklung und Umsetzung von GLASS ("Global Antimicrobial Surveillance System") unter der Lei-tung der WHO.
TOR (ii) Ausweitung des Konzepts für das "Tricycle"-Projekt zur Schließung der Übertragungslücke zwischen Antibiotikaresistenzen beim Menschen und beim Tier unter der Leitung der WHO.

Cooperation Partners:

AMR Division, World Health Organization (WHO), Genf, Schweiz (weitere Informationen siehe https://www.who.int/health-topics/antimicrobial-resistance)

Project Details:
Gap junctions (Gj) are composed of two hemichannels called connexons, which are responsible for direct intercellular communication between adjoining cells. Each cell contains one connexon, composed of six connexin (cx) proteins. The so far discovered functions of Gj are mostly limited to the transport of molecules and ions (< 1 kDa). Nevertheless these junctions tend to be selective and specialize in cellular growth and differentiation (Bruzzone et al., 1996; Kumar and Gilula, 1996). As of today there are at least twenty different cx genes coding for Gj in humans and mice. One of the most researched Gj proteins is Cx43. In the testis, Cx43 is located between two Sertoli cells (SC) and between SC and germ cells (GC), it is involved in testicular development, GC and SC differentiation and spermatogenesis. SC nurture the developing GC and aid in their translocation and development from the basal to the adluminal compartment of the seminiferous tubule. Cx43 is further participating in blood-testis barrier formation and composition together with tight and adherens junctions as member of the "SC-SC junctional complexes" (Carrette et al., 2010).
A conditional SC-specific knockout (KO) of the Gja1 gene (SCCx43KO) revealed Cx43 expression in SC as an absolute requirement for normal testicular development and initiation of spermatogenesis (Brehm et al., 2007; Sridharan et al., 2007). Adult SCCx43KO mice showed normal testis descent, but testis size and weight was drastically lower when compared with heterozygous and WT littermates. Histological analysis revealed that SC specific deletion of Cx43 mostly results in an arrest of spermatogenesis at the level of spermatogonia or SC-only syndrome, intratubular cell clusters, abnormal SC cytoplasmic vacuoles, increased SC numbers and reduced number of spermatogonia per seminiferous tubule. Furthermore, as SCs were found to be still proliferating in adult mice (Sridharan et al., 2007), it was postulated that lack of Cx43 expression in SCs caused these somatic cells to remain in an apparently permanent proliferative state. These results emphasize the critical contribution of Cx43 to the normal maturational progression of SCs which normally results in the cessation of SC mitogenesis during the pubertal period.
Thus, as of today only one mouse stem with SCCx43KO-/- has been established in vivo (Brehm et al., 2007; Sridharan et al., 2007), yet no successful in vitro culturization of a &#61508;Cx43 SC line has been published. Although Carette et al. (2010) were successful in a partial inhibition of the Gj through siRNAs, a complete in vitro knockout may provide beneficial results in understanding the roles of Cx43 for normal spermatogenesis and may help to develop a mechanistic hypothesis in understanding the altered functions of Cx43 in SC leading to impaired spermatogenesis.

Project Details:
In diesem Projekt werden in einem transgenen Mausmodell die Folgen einer Sertoli Zell-spezifischen Deletion des Connexin43-Gens auf die Regulation der Spermatogenese u.a. mittels Microarray und qRT-PCR untersucht. Ausgewählte signifikant veränderte Kandidatengene aus den Mausversuchen werden zudem mit Hodenbiopsien von infertilen Männern verglichen.
Das Projekt bildet die Grundlage verschiedener Forschungsprojekte und Dissertationen sowie künftiger Drittmittelprojekte.
Geldgeber:
DFG, Klinische Forschergruppe KFO181, Male factor infertility due to impaired spermatogenesis
Volumen: 250000 €

Results:

https://www.sciencedirect.com/science/article/pii/S1642431X17302371?via%3Dihub

Cooperation Partners:

Dr. Daniela Fietz, JLU Giessen

Klinische Forschergruppe Giessen + Marburg

http://www.uni-giessen.de/cms/fbz/fb11/forschung/forschergruppen/kfo_181/home

Project Details:
The project is aimed at the modelling and analysis of diverse veterinary epidemio-logic data arising from consultant work. The range of statistical modelling ap-proaches includes general models and special topics like logistic regression, zero inflation, non-linear regression (especially growth curves), cluster analysis, contin-gency table analysis and multi-block redundancy analysis (multi-factorial and multi-variate linear regression analysis).

Results:

Kreienbrock L, Pigeot I, Ahrens W.

Epidemiologische Methoden. Berlin: Springer Spektrum; 5. Auflage 2012.

ISBN: 978-3-8274-2333-7

 

Berke, O. Modified median polish kriging and its applica-tion to the Wolfcamp-Aquifer data.

Environmetrics. 2001;12(8):731-48.

 

Kreienbrock L, Broll S. Methodische Aspekte zur Qualitätssicherung veteri-närepidemiologischer Studien. [Methodologic aspects of quality assurance in veterinary epi-demiological studies].

Dtsch Tierarztl Wochenschr. 1999 Sep;106(9):381-5.

Cooperation Partners:

- Fachbereich Statistik, Universität Dortmund

- Leibniz-Institut für Epidemiologie, Bremen

- Hochschule Hannover

- Department of Population Medicine, University of Guelph

Funding: BMBF, DFG (Ra 502/7), DAAD, VolkswagenStiftung, Bundesamt für Naturschutz, BIOPAT e.V., private Spender, 292.450 EUR

Project Details:
The development of effective conservation measures for endangered species requires a detailed knowledge on the remaining individual numbers, the distribution of species and the factors causing potential threats to their survival. Moreover, it is important to understand the degree of intra-specific differentiation (e.g. phenotypic, ecological, genetic) that can be the result of rather recent (anthropogenic) or ancient evolutionary processes (barriers, landscape). The aim of this project is to understand the population structure of different lemur species across their distribution in view of drastic anthropogenic disturbances. Ancient and recent processes of genetic differentiation shall be identified in order to develop effective conservation measures. With this analysis, we will gain important insights into the evolutionarily significant units as well as and the management units of these threatened primates that will be needed to formulate long-term management plans.

Results:

e.g.

Phelps, L.N.; Razanatsoa, E.; Davis, D.S.; Hackel, J.; Rasolondrainy, T.; Tiley, G.P.; Cox, R.; Andermann, T.; Andriambololonera, S.; Andriamiarisoa, L.R.; Antonelli, A.; Burney, D.; Besnard, G.; Birkinshaw, C.; Bond, W.; Chikhi, L.; Fernández-García, V.; Gillson, L.; Godfrey, L.; Haberle, S.; Hansford, J.; Hempson, G.; Hixon, S.; Joseph, G.S.; Mangut, C.L.; Marchant, R.; Montade, V.; Pham, K.V.; Rabehevitra, D.; Radespiel, U.; Raharimampionona, J.; Rajaonah, M.T.; Rakotomalala, N.; Ramiadantsoa, T.; Ramiandrisoa, B.A.; Ranarijaona, H.L.T.; Randriamboavonjy, T.; Randrianarimanana, F.; Randriatsara, F.; Ratsirarson, J.; Razafimanantsoa, A.H.I.; Salmona, J.; Samonds, K.; Scroxton, N.; Seymour, C.; Steffens, T.; Teixeira, H.; Voarintsoa, N.R.G.; Waeber, P.O.; Wilmé, L.; Yoder, A.D.; Convery Fisher, E.; Solofondranohatra, C.; van Elst, T.; Crowley, B.; Douglass, K.; Vorontsova, M.S.; Lehmann, C. (2025). Advancing transdisciplinary research on Madagascar’s grassy biomes to support resilience in ecosystems and livelihoods. Ecological Monographs, 95:e70011. https://doi.org/10.1002/ecm.70011

 

Everson, K.M.; Pozzi, L.; Barrett, M.A.; Blair, M.E.; Donohue, M.E.; Kappeler, P.M.; Kitchener, A.C.; Lemmon, A.R.; Lemmon, E.M.; Pavón-Vásquez, C.J.; Radespiel, U.; Randrianambinina, B.; Rasoloarison, R.M.; Rasoloharijaona, S.; Roos, C.; Salmona, J.; Yoder, A.D.; Zenil-Ferguson, R.; Zinner, D.; Weisrock, D.W. (2025): Multiple bursts of speciation in Madagascar’s endangered lemurs. Nat. Commun., 16:7070. https://doi.org/10.1038/s41467-025-62310-y.

 

Van Elst, T.; Sgarlata, G.M.; Schüßler, D.; Tiley, G.P.; Poelstra, J.W.; Scheumann, M.; Blanco, M.B.; Aleixo-Pais, I.G.; Evasoa, M.R.; Ganzhorn, J.U.; Goodman, S.M.; Hasiniaina, H.F.; Hohenlohe, P.A.; Ibouroi, M.T.; Iribar-Poluzuelo, A.; Jan, F.; Kappeler, P.M.; Le Pors, B.; Manzi, S.; Olivieri, G.; Rakotonanahary, A.N.; Rakotondranary, S.J.; Rakotondravony, R.; Ranaivoarisoa, J.F.; Randrianambinina, B.; Rasoloarison, R.M.; Rasoloharijaona, S.; Rasolondraibe, E.; Teixeira, H.; Zaonarivelo, J.R.; Louis, E.E. Jr.; Yoder, A.D.; Chikhi, L.; Radespiel, U.; Salmona, J. (2025): Integrative taxonomy clarifies the evolution of a cryptic primate clade. Nature Ecol. Evol., 9, 57-72. https://doi.org/10.1038/s41559-024-02547-w

 

Schüßler, D., Rafmantanantsoa, S.M.; Ratsimbazafy, J.H.; Richter, T.; Radespiel, U. (2023): Documentation of commercial and subsistence hunting of Critically Endangered Black-and-white Ruffed Lemurs (Varecia variegata) in northeastern Madagascar. Biodiversity and Conservation. https://doi.org/10.1007/s10531-023-02744-2.

 

Ramilison, M.L.; Andriatsitohaina, B.; Chell, C.; Rakotondravony, R.; Radespiel, U.; Ramsay, M.S. (2021): Distribution of the critically endangered Coquerel’s Sifaka (Propithecus coquereli) in a fragmented landscape. Afr. J. of Ecology 59, 350-358. Doi:10.1111/aje.12844.

Cooperation Partners:

Tobias van Elst, PhD, Universität Zürich, Schweiz

Dr. Dominik Schüßler, Universität Hildesheim

Prof. B. Randrianambinina, University of Mahajanga, Madagaskar

Dr. R. Rakotondravony, University of Mahajanga, Madagaskar

Prof. S. Rasoloharijaona, University of Mahajanga, Madagaskar

Dr. L. Chikhi, Universität Toulouse, Frankreich

Prof. M.W. Bruford, Cardiff University, UK

Dr. D. Rakotondravony, University of Antananarivo, Madagaskar

Dr. F. Ratsoavina, University of Antananarivo, Madagascar

Prof. J. Ratsimbazafy, University of Antananarivo, Madagascar

Groupe d'Étude et de Recherche sur les Primates de Madagascar, Madagaskar

Project Details:
Ziel der Entwicklung von Leitlinien zur Guten Klinischen Praxis war die Gewährleistung international anerkannter ethischer und wissenschaftlicher Qualitätsanforderungen in zulassungsrelevanten Arzneimittelstudien. Da ein hoher Qualitätsstandard aber auch in anderen Bereichen wünschenswert ist, werden GCP Prinzipien zunehmend auch bei anderen Studien oder Untersuchungen angewandt.

Dieses Projekt verfolgt das Ziel, den Inhalt der Guideline dem betroffenen Personenkreis bekannt zu machen und darauf hinzuwirken, die Qualitätsanforderungen auch im Bereich der universitären Forschungsprojekte umzusetzen. Aus biometrischer Sicht wird dabei besonderes Gewicht auf die die Statistik und das Datenmanagement betreffenden Teile der Leitlinie gelegt.

Neben der Information werden dazu auch Dienstleistungen, etwa die Mitarbeit bei der Erstellung von Prüfplänen oder Review von Studienprotokollen angeboten. Insbesondere wird angestrebt, bei vom Institut betreuten und ausgewerteten Studien GCP-konform zu arbeiten und ggf. dazu notwendige "Standard Operating Procedures" (SOPs) zu erarbeiten.

Results:

Kreienbrock L, Pigeot I, Ahrens W. Epidemiologische Methoden. Berlin: Springer Spektrum; 5. Auflage 2012. ISBN: 978-3-8274-2333-7

 

Glaser S, Kreienbrock L. Stichprobenplanung bei veterinärmedizinischen Studien. Ein Leitfaden zur Bestimmung des Untersuchungsumfangs. Hannover: Schlüter-sche; 2011. ISBN-13: 978-389993-078-8 ISBN-10: 3-89993-078-9

 

Glaser S, Dahms S, Röhmel J, Weiß H, Kreienbrock L. Statistische Grundlagen von "Good Clinical Practice" in der Veterinärmedizin - ein Positionspapier zur Planung, Durchführung und Auswertung empirischer Untersuchungen. Dtsch Tierarztl Wo-chenschr. 2002 Feb;109(2):68-72.