Andreas Sauerbrei

Universitätsklinikum Jena, Jena, Thuringia, Germany

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Publications (163)381.55 Total impact

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    ABSTRACT: The use of genotypic resistance testing of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) is increasing because the rapid availability of results significantly improves the treatment of severe infections, especially in immunocompromised patients. However, an essential precondition is a broad knowledge of natural polymorphisms and resistance-associated mutations in the thymidine kinase (TK) and DNA polymerase (pol) genes, of which the DNA polymerase (Pol) enzyme is targeted by the highly effective antiviral drugs in clinical use. Thus, this review presents a database of all non-synonymous mutations of TK and DNA pol genes of HSV-1 and HSV-2 whose association with resistance or natural gene polymorphism has been clarified by phenotypic and/or functional assays. In addition, the laboratory methods for verifying natural polymorphisms or resistance mutations are summarized. This database can help considerably to facilitate the interpretation of genotypic resistance findings in clinical HSV-1 and HSV-2 strains.
    Journal of Antimicrobial Chemotherapy 10/2015; DOI:10.1093/jac/dkv285 · 5.31 Impact Factor
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    ABSTRACT: Enteroviruses cause various acute and chronic diseases. The most promising therapeutics for these infections are capsid-binding molecules. These can act against a broad spectrum of enteroviruses, but emerging resistant virus variants threaten their efficacy. All known enterovirus variants with high-level resistance toward capsid-binding molecules have mutations of residues directly involved in the formation of the hydrophobic binding site. This is a first report of substitutions outside the binding pocket causing this type of drug resistance: I1207K and I1207R of the viral capsid protein 1 of coxsackievirus B3. Both substitutions completely abolish the antiviral activity of pleconaril (a capsid-binding molecule) but do not affect viral replication rates in vitro. Molecular dynamics simulations indicate that the resistance mechanism is mediated by a conformational rearrangement of R1095, which is a neighboring residue of 1207 located at the heel of the binding pocket. These insights provide a basis for the design of resistance-breaking inhibitors.
    Antiviral research 09/2015; DOI:10.1016/j.antiviral.2015.09.009 · 3.94 Impact Factor
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    ABSTRACT: There is only little information about the role of mutations of the thymidine kinase (TK) and DNA polymerase (pol) genes of herpes simplex virus type 2 (HSV-2) for the development of antiviral resistance. In this study, the polymorphism of TK and DNA pol genes was examined in 82 clinical isolates collected routinely between 1973 and 2013. If novel, presently unclear or resistance-related mutations were found, the resistance phenotype against acyclovir (ACV) and foscarnet (FOS) was analyzed. The four novel amino acid changes G150D, A157T, R248W, L342W and the hitherto phenotypically unclear substitution T131M within the TK gene were identified as natural polymorphisms. Within the DNA pol gene, 17 novel substitutions and the to-date unclear change R628C were characterized as part of natural gene polymorphism. Two novel DNA pol mutations were linked to resistance (M910T) and weak susceptibility to ACV (684 insertion ED), respectively. In one isolate, the genomic cause of ACV resistance could not be identified. Phylogenetic analysis including sequences of this study and of the GenBank revealed a hierarchy of mutation clusters in TK displaying G39E as first common mutation step, followed by N78D and L140F. In conclusion, the present findings allow a deeper insight in the variability of HSV-2 TK and DNA pol genes. The most common substitution G39E can be excluded as unique cause of HSV-2 resistance. This study supports once more the importance of phenotypic adjustment of genotypic results to enhance the clinical utility of genotypic findings. Copyright © 2015 Elsevier GmbH. All rights reserved.
    International journal of medical microbiology: IJMM 08/2015; DOI:10.1016/j.ijmm.2015.08.014 · 3.61 Impact Factor
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    ABSTRACT: Up to now, three distinct genotypes, A, B and C, of herpes simplex virus type 1 (HSV-1), based on polymorphisms in the US4 and US7 genes, have been reported. Here, we propose to include an additional polymorphism of the US2 gene. The refined genotyping method was validated using 423 clinical isolates from patients with different HSV-1 diseases. The proportions of three US2 genotypes were A, 46.6 %; B, 23.2 %; and C, 30.2 %. Genotype A of US2 and US4/US7 showed a highly significant correlation. In addition, the frequency of genotype A was significantly higher in women than in men with herpes labialis.
    Archives of Virology 08/2015; DOI:10.1007/s00705-015-2568-y · 2.39 Impact Factor
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    ABSTRACT: Three hundred and two clinical herpes simplex virus type 1 (HSV-1) strains, collected over four decades from 1973 to 2014, were characterized retrospectively for drug resistance. All HSV-1 isolates were analyzed genotypically for non-synonymous mutations in the thymidine kinase (TK) and DNA polymerase (DNA pol) genes. The resistance phenotype against acyclovir (ACV) and/or foscarnet (FOS) was examined in case of novel, unclear or resistance-related mutations. Twenty-six novel natural polymorphisms could be detected in the TK and 69 in the DNA pol gene. Furthermore, three novel resistance-associated mutations (two in TK and one in DNA pol gene) were analyzed and eight known but hitherto unclear amino acid (aa) substitutions (two encoded in TK and six in DNA pol gene) could be clarified. Between 1973 and 2014, the distribution of aa changes related to the natural gene polymorphism of TK and DNA pol remained largely stable. For 16 isolates, ACV resistance and, for one, resistance to ACV plus FOS was confirmed phenotypically. Acyclovir-resistant strains were observed from the year 1995 onwards predominantly in immunosuppressed patients especially with stem cell transplantation and the number of ACV-resistant strains increased during the last two decades. The data confirm the strong genetic variability, which is more pronounced in the DNA pol than in the TK gene, and will facilitate considerably the rapid genotypic diagnosis of HSV-1 resistance. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Antimicrobial Agents and Chemotherapy 06/2015; 59(8). DOI:10.1128/AAC.00977-15 · 4.48 Impact Factor
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    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 04/2015; 58(4-5):493-504. DOI:10.1007/s00103-015-2131-8 · 1.42 Impact Factor
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    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 04/2015; 58(4-5):491-492. DOI:10.1007/s00103-015-2130-9 · 1.42 Impact Factor
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    ABSTRACT: In this study, approaches were developed to examine the phenotype of non-viable clinical VZV strains with amino acid (aa) substitutions in the thymidine kinase (TK, ORF36) and/or DNA polymerase (Pol, ORF28) suspected to cause resistance to antivirals. Initially, recombinant TK proteins containing aa substitutions described as known or suspected cause of antiviral resistance were analyzed by measuring the TK activity applying a modified commercial enzyme immunoassay. To examine the effect of these TK and several Pol substitutions on the replication of recombinant virus strains, the method of en-passant mutagenesis was used. Targeted mutations within the ORF36 and/or ORF28 and an autonomously expressed gene of the monomeric red fluores-cent protein for plaque identification were introduced into the European wild-type VZV strain HJO. Plaque reduction assays revealed that the aa substitutions with unknown function in TK, Q303stop, N334stop, A163stop, and aa Δ7-74, were associated with resistance against acyclovir (ACV), penciclovir, or brivudin, whereas L73I and the Pol substitutions T237K and A955T revealed sensitive viral phenotypes. The results were confirmed by quantitative PCR measuring the viral load under increasing ACV concentrations. In conclusion, analyzing the enzymatic activity of recombinant TK proteins represents a useful tool to evaluate the significance of aa substitutions for antiviral resistance of clinical VZV strains. However, direct testing of replication-competent viruses by the introduction of non-synonymous mutations in a VZV bacterial artificial chromosome using en-passant mutagenesis led to reliable phenotypic results. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
    Antimicrobial Agents and Chemotherapy 02/2015; 59(5). DOI:10.1128/AAC.05115-14 · 4.48 Impact Factor
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    ABSTRACT: The administration of drugs to inhibit metabolic pathways not only reduces the risk of obesity-induced diseases in humans but may also hamper the replication of different viral pathogens. In order to investigate the value of the US Food and Drug Administration-approved anti-obesity drug orlistat in view of its anti-viral activity against different human-pathogenic viruses, several anti-viral studies, electron microscopy analyses as well as fatty acid uptake experiments were performed. The results indicate that administrations of non-cytotoxic concentrations of orlistat reduced the replication of coxsackievirus B3 (CVB3) in different cell types significantly. Moreover, orlistat revealed cell protective effects and modified the formation of multi-layered structures in CVB3-infected cells, which are necessary for viral replication. Lowering fatty acid uptake from the extracellular environment by phloretin administrations had only marginal impact on CVB3 replication. Finally, orlistat reduced also the replication of varicella-zoster virus moderately but had no significant influence on the replication of influenza A viruses. The data support further experiments into the value of orlistat as an inhibitor of the fatty acid synthase to develop new anti-viral compounds, which are based on the modulation of cellular metabolic pathways.
    Medical Microbiology and Immunology 02/2015; 204(6). DOI:10.1007/s00430-015-0391-4 · 3.04 Impact Factor
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    ABSTRACT: Aims: In this study, we analyze the challenges involved in detecting novel neuraminidase inhibitors (NAIs) and offer strategies to overcome them with complementary bioassays. Materials & Methods: We investigated the inhibitory activities of NAIs (oseltamivir, zanamivir, DANA, katsumadain A and remazol) as well as non-NAIs (amantadine, nucleozin and rifampicin) on influenzaviral and bacterial (Streptococcus pneumoniae, Clostridium perfringens and Vibrio cholerae) neuraminidases (NAs) with chemiluminescence (CL)- and fluorescence (FL)-based assays. Furthermore, hemagglutination-based NA inhibition assays were established. Results: Our study shows three types of signal interference affecting the readout of biochemical assays: self-FL (katsumadain A and remazol), FL quenching (rifampicin) and CL quenching (rifampicin, remazol, nucleozin and katsumadain A). These challenges were overcome by hemagglutination-based assays. Conclusion: The latter allow a robust performance in discriminating NAIs and non-NAIs.
    Future Virology 02/2015; 10(2):77-88. DOI:10.2217/fvl.14.97 · 1.01 Impact Factor
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    ABSTRACT: Streptococcus (S.) pneumoniae is a major cause of secondary bacterial pneumonia during influenza epidemics. Neuraminidase is a virulence factor of both pneumococci and influenza viruses. Bacterial neuraminidases are structurally related to viral neuraminidases and susceptible to oseltamivir, an inhibitor designed to target viral neuraminidases. This prompted us to evaluate the antipneumococcal potential of two neuraminidase inhibiting natural compounds, the diarylheptanoid katsumadain A and the isoprenylated flavone artocarpin. Chemiluminescence, fluorescence-, and hemagglutination-based enzyme assays were applied to determine the inhibitory efficiency (IC50 value) of the tested compounds towards pneumococcal neuraminidase. The mechanism of inhibition was studied via enzyme kinetics with recombinant NanA neuraminidase. Unlike oseltamivir, which competes with the natural substrate of neuraminidase, artocarpin exhibits a mixed-type inhibition with a Ki value of 9.70 μM. Remarkably, artocarpin was the only neuraminidase inhibitor for which an inhibitory effect in pneumococcal growth (MIC: 0.99–5.75 μM) and biofilm formation (MBIC: 1.15–2.97 μM) was observable. In addition, we discovered that the bactericidal effect of artocarpin can reduce the viability of pneumococci by a factor of >1000, without obvious harm to lung epithelial cells. This renders artocarpin a promising natural product for further investigations.
    International Journal of Medical Microbiology 12/2014; 305(3). DOI:10.1016/j.ijmm.2014.12.004 · 3.61 Impact Factor
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    Nora Seidel · Andreas Sauerbrei · Peter Wutzler · Michaela Schmidtke
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    ABSTRACT: The amino acid substitution of aspartic acid to glycine in hemagglutinin (HA) in position 222 (HA-D222G) as well as HA-222D/G polymorphism of pandemic (H1N1) 2009 influenza viruses (A(H1N1)pdm09) were frequently reported in severe influenza in humans and mice. Their impact on viral pathogenicity and the course of influenza has been discussed controversially and the underlying mechanism remained unclarified. In the present study, BALB/c mice, infected with the once mouse lung- and cell-passaged A(H1N1)pdm09 isolate A/Jena/5258/09 (mpJena/5258), developed severe pneumonia. From day 2 to 3 or 4 post infection (p.i.) symptoms (body weight loss and clinical score) continuously worsened. After a short disease stagnation or even recovery phase in most mice, severity of disease further increased on days 6 and 7 p.i. Thereafter, surviving mice recovered. A 45 times higher virus titer maximum in the lung than in the trachea on day 2 p.i. and significantly higher tracheal virus titers compared to lung on day 6 p.i. indicated changes in the organ tropism during infection. Sequence analysis revealed an HA-222D/G polymorphism. HA-D222 and HA-G222 variants co-circulated in lung and trachea. Whereas, HA-D222 variant predominated in the lung, HA-G222 became the major variant in the trachea after day 4 p.i. This was accompanied by lower neutralizing antibody titers and broader receptor recognition including terminal sialic acid α-2,3-linked galactose, which is abundant on mouse trachea epithelial cells. Plaque-purified HA-G222-mpJena/5258 virus induced severe influenza with maximum symptom on day 6 p.i. These results demonstrated for the first time that HA-222D/G quasispecies of A(H1N1)pdm09 caused severe biphasic influenza because of fast viral intra-host evolution, which enabled partial antibody escape and minor changes in receptor binding.
    PLoS ONE 08/2014; 9(8):e104233. DOI:10.1371/journal.pone.0104233 · 3.23 Impact Factor
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    ABSTRACT: The avian-like swine influenza viruses emerged in 1979 in Belgium and Germany. Thereafter, they spread through many European swine-producing countries, replaced the circulating classical swine H1N1 influenza viruses and became endemic. Serological and subsequent molecular data indicated an avian source, but details remained obscure due to a lack of relevant avian influenza virus sequence data. Here, the origin of the European avian-like swine influenza viruses was analyzed using a collection of sixteen European swine H1N1 influenza viruses sampled in 1979-1981 in Germany, the Netherlands, Belgium, Italy and France as well as several contemporaneous avian influenza viruses of various serotypes. The phylogenetic trees suggest a triple reassortant with a unique genotype constellation. Time-resolved maximum clade credibility trees indicate times to the most recent common ancestors of 34-46 years (before 2008) depending on the RNA segment and the method of tree inference.
    Journal of General Virology 07/2014; 95(Pt_11). DOI:10.1099/vir.0.068569-0 · 3.18 Impact Factor
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    ABSTRACT: An increase in acute autochthonous hepatitis E virus (HEV) infections has been recorded in Germany. These are suspected to be zoonotically transmitted from wild boar, deer and domestic pig. The latter may represent a major reservoir for HEV. In this study, 537 sera from humans living in Westphalia and Lower Saxony, representing areas of high pig density in Germany, were tested for the presence of HEV-specific antibodies. Among them were 302 individuals with occupational, direct contact to pigs and 235 individuals without direct contact to pigs. Two commercial tests and one in-house assay were applied for the detection of HEV-specific immunoglobulin G (IgG) antibodies. Sera were also tested in an assay that detects all classes of HEV-specific antibodies. Depending on the test used, the seroprevalence ranged from 4.1 to 27.9 %. Exposition to pigs was found to be associated with a significantly higher seroprevalence in subjects with contact to pigs (13.2-32.8 %) compared with that in non-exposed humans (7.7-21.7 %). In particular, individuals younger than 40 years with occupational exposure exhibited a markedly higher HEV seroprevalence compared with non-exposed individuals of that age group. In general, HEV seroprevalence increased with age resulting in a similar prevalence level in the age group of ≥50 years for exposed and non-exposed individuals. Analysis of all sera by a commercial anti-HEV IgM ELISA revealed 35 positive and 25 borderline samples. However, only one positive serum could be confirmed by an IgM line assay. Selected samples from IgM and/or IgG as well as total HEV antibody-positive individuals were also tested for the presence of HEV RNA. In one of the 78 samples, the only IgM ELISA positive and IgM line assay confirmed sample, RNA of HEV genotype 3 was detected. This sequence has high similarity to HEV sequences obtained from wild boars and domestic pigs from Germany and The Netherlands. This study demonstrates that in addition to the consumption of raw or undercooked meat, direct contact to pigs has to be considered as an additional risk factor for HEV infection.
    Medical Microbiology and Immunology 04/2014; 203(4). DOI:10.1007/s00430-014-0336-3 · 3.04 Impact Factor
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    ABSTRACT: The role of mutations in the thymidine kinase (TK, UL23) and DNA polymerase (pol, UL30) genes of herpes simplex virus (HSV) for development of different resistance phenotypes has to be exactly determined before genotypic resistance testing can be implemented in patient's care. Furthermore, the occurrence of cross-resistance is of utmost clinical importance. In this study, clinical HSV-1 isolates obtained between 2004 and 2011 from 26 patients after stem cell transplantation were examined in parallel by phenotypic and genotypic resistance testing. Thirteen isolates, which were phenotypically cross-resistant to acyclovir (ACV), penciclovir (PCV) and brivudin (BVDU), exhibited consistently frameshift or non-synonymous mutations in the TK gene known to confer resistance. One of these mutations (insertion of C at the nucleotide positions 1061-1065) has not been described before. Seven strains, phenotypically resistant to ACV and PCV and, except one each, sensitive to BVDU and resistant to foscarnet (FOS), carried uniformly resistance-related substitutions in the DNA pol gene. Finally, 3 isolates, resistant to ACV, PCV and 2 out of these also resistant to BVDU, had known but also unclear substitutions in the TK and DNA pol genes, and 3 isolates were completely sensitive. In conclusion, clinical ACV-resistant HSV-1 isolates, carrying resistance-associated mutations in the TK gene, can be regarded as cross-resistant to other nucleoside analogs such as BVDU. In contrast, clinical FOS-resistant HSV-1 strains which are cross-resistant to ACV may be sensitive to BVDU. This has to be considered for drug changes in antiviral treatment in case of ACV resistance.
    Antiviral research 04/2014; 107C(1). DOI:10.1016/j.antiviral.2014.03.015 · 3.94 Impact Factor
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    ABSTRACT: Influenza virus A/whale/Maine/328B/1984 (H13N2) was isolated from a diseased pilot whale. Since only a partial sequence was available, its complete genome was sequenced and compared to the sequences of subtype H13 influenza viruses from shorebirds and various influenza viruses of marine mammals. The data reveal a rare genotype constellation with all gene segments derived of an influenza virus adapted to gulls, terns and waders. In contrast, the phylogenetic trees indicate that the majority of influenza viruses isolated from marine mammals derived from influenza viruses adapted to geese and ducks. We conclude that A/whale/Maine/328B/1984 is the first record of an infection of a marine mammal from a gull-origin influenza virus.
    Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases 04/2014; 24. DOI:10.1016/j.meegid.2014.03.026 · 3.02 Impact Factor
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    ABSTRACT: The emergence of new influenza viruses like the pandemic H1N1 influenza A virus in 2009 (A(H1N1)pdm09) with unpredictable difficulties in vaccine coverage and established antiviral treatment protocols emphasizes the need of new murine models to prove the activity of novel antiviral compounds in vivo. The aim of the present study was to develop a small-scale mathematical model based on easily attainable experimental data to explain differences in influenza kinetics induced by different virus strains in mice. To develop a three-dimensional ordinary differential equation model of influenza dynamics, the following variables were included: (i) viral pathogenicity (P), (ii) antiviral immune defense (D), and (iii) inflammation due to pro-inflammatory response (I). Influenza virus-induced symptoms (clinical score S) in mice provided the basis for calculations of P and I. Both, mono- and biphasic course of mild to severe influenza induced by three clinical A(H1N1)pdm09 strains and one European swine H1N2 virus were comparatively and quantitatively studied by fitting the mathematical model to the experimental data. The model hypothesizes reasons for mild and severe influenza with mono- as well as biphasic course of disease. According to modeling results, the second peak of the biphasic course of infection is caused by inflammation. The parameters (i) maximum primary pathogenicity, (ii) viral infection rate, and (iii) rate of activation of the immune system represent most important parameters that quantitatively characterize the different pattern of virus-specific influenza kinetics.
    Bio Systems 04/2014; 118(1). DOI:10.1016/j.biosystems.2014.02.004 · 1.55 Impact Factor
  • Andreas Sauerbrei · Kathrin Bohn
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    ABSTRACT: Resistance testing of antivirals to herpes simplex virus type 1 can be done by phenotypic and genotypic methods. The determination of a resistant phenotype is based on the calculation of inhibitory concentrations for the antiviral drug, which should be tested. The main advantage is a clear interpretation of laboratory findings, but the method is time consuming and a considerable experience is required for handling infectious virus. Genotypic resistance testing is based on the detection of resistance-related mutations in viral genes encoding the thymidine kinase and DNA polymerase by means of amplification and sequencing. This approach has the advantage of being faster, but only frameshift mutations and stops of translation can be interpreted without doubt and numerous amino acid substitutions are diagnostically less conclusive.
    Methods in molecular biology (Clifton, N.J.) 03/2014; 1144:149-65. DOI:10.1007/978-1-4939-0428-0_10 · 1.29 Impact Factor
  • A Kühnl · C Rien · K Spengler · N Kryeziu · A Sauerbrei · R Heller · A Henke
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    ABSTRACT: After successful invasion of susceptible hosts, systemic distribution of coxsackievirus B3 (CVB3) most likely requires interactions with the endothelial system. Thereby, infection of endothelial cells occurs directly or viruses and/or virus-infected leukocytes migrate through the endothelial barrier. Many of these processes have not been studied so far. In order to analyze viral replication in the endothelium, human umbilical vein endothelial cells (HUVEC) were isolated and infected with CVB3. Time-course experiments revealed maximal viral replication at 10-24 h and viral RNA persistence up to 120 h post-infection (p. i.) without the induction of obvious general cytopathic effects or the loss of cellular viability. However, the application of the EGFP-expressing recombinant virus variant CVB3/EGFP revealed shrinkage and death of individual cells. Using infectious center assays, a noticeable CVB3 replication occurred on an average of 20 % of HUVEC at 10 h p. i. This may be in part due to a higher coxsackievirus/adenovirus receptor expression in a small subgroup of HUVEC (5-7 %) as analyzed by flow cytometry. Interestingly, CVB3 replication escalated and cellular susceptibility increased significantly after reversal of cell cycle arrest caused by serum deprivation indicating that reactivation of cellular metabolism may help to promote CVB3 replication. Finally, CVB3-infected HUVEC cultures revealed increased DNA fragmentation, and inhibition of caspase activity caused an accumulation of intracellular virus particles indicating that apoptotic processes are involved in virus release mechanisms. Based on these observations, it is assumed that CVB3 replicates efficiently in human endothelial cells. But how this specific infection of the endothelium may influence viral spread in the infected host needs to be investigated in the future.
    Medical Microbiology and Immunology 03/2014; 203(4). DOI:10.1007/s00430-014-0333-6 · 3.04 Impact Factor
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    ABSTRACT: The prevalence of influenza A and B virus-specific IgG was determined in sera taken between 2008 and 2010 from 1,665 children aged 0-17 years and 400 blood donors in Germany. ELISA on the basis of whole virus antigens was applied. Nearly all children aged nine years and older had antibodies against influenza A. In contrast, 40% of children aged 0-4 years did not have any influenza A virus-specific IgG antibodies. Eighty-six percent of 0-6 year-olds, 47% of 7-12 year-olds and 20% of 13-17 year-olds were serologically naïve to influenza B viruses. By the age of 18 years, influenza B seroprevalence reached approximately 90%. There were obvious regional differences in the seroprevalence of influenza B in Germany. In conclusion, seroprevalences of influenza A and influenza B increase gradually during childhood. The majority of children older than eight years have basal immunity to influenza A, while comparable immunity against influenza B is only acquired at the age of 18 years. Children aged 0-6 years, showing an overall seroprevalence of 67% for influenza A and of 14% for influenza B, are especially at risk for primary infections during influenza B seasons.
    Eurosurveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 02/2014; 19(5). DOI:10.2807/1560-7917.ES2014.19.5.20687 · 5.72 Impact Factor

Publication Stats

2k Citations
381.55 Total Impact Points


  • 2002–2014
    • Universitätsklinikum Jena
      • Institute of Virology and Antiviral Therapy
      Jena, Thuringia, Germany
  • 1996–2014
    • Friedrich Schiller University Jena
      • Institute of Virology and Antiviral Therapy
      Jena, Thuringia, Germany
  • 2012
    • University College London
      Londinium, England, United Kingdom
  • 2011
    • Leibniz Institute for Age Research - Fritz Lipmann Institute
      • Genome Analysis
      Jena, Thuringia, Germany
  • 2008
    • Universität Hamburg
      • Institute of Organic Chemistry
      Hamburg, Hamburg, Germany