Guntram Christiansen


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Senior Scientist


Functional genetics

+43 6232 3125-32
+43 6232 3578
guntram.christiansen@oeaw.ac.at
Employment History Research   Projects   Publications
Employment History

2011 – present: Senior scientist at the Institute for Limnology in Mondsee

2005 – 2011: Research fellow at the Institute for Limnology in Mondsee

2003 – 2005 Post doc position at the University of Hawaii at Manoa, Honolulu, Department of Chemistry

1999 – 2002 PhD studies at the Humboldt Universität zu Berlin, Institut für Biologie/Genetik

Research

1. Genomic/metagenomic studies

Due to DNA-sequencing methods which became available in the last years it is possible to unravel the genetic information of a microbial community with a high resolution. We are interested in monitoring possible compositional changes of the biotic community of fresh water lakes in relation to different factors eg temperature and pH changes, catastrophic events like algal blooms etc. Currently we address these questions with ultra deep amplicon sequencing. In the future we will attempt to unravel the information of whole genomes isolated from fractionated environmental samples in order to identify and quantify genomic recombination events of selected species and possible correlations with environmental factors. Additionally the microevolution of selected genes of ecological relevance will be investigated.
   
2. Genetic analyses of single cells/colonies/filaments

The genetic analysis of single cells/colonies/filaments isolated directly from the environment bears great potential as it circumvents several shortcomings of cultivation-dependent approaches. While PCR analysis of isolated single cells/colonies/filaments is routine we are aiming to establish dedicated protocols enabling the repeated analysis of one environmental isolate. At the moment we are able to isolate high molecular weight DNA from single cyanobacterial filaments sufficient for several dozens of PCR experiments. These approaches represent a less resource consuming alternative to cultivation independent (meta)genomic studies.

3. Functional consequences of recorded genetic diversity

Comparisons of certain gene loci within isolates of one species repeatedly show genetic variation. We are interested in the consequences of this genetic diversity for the biochemical activities of the proteins.  By biochemical characterization of enzymes involved in secondary metabolite synthesis we could show that only a few point mutations increase the number of structural variants of a bioactive metabolite (Christiansen et al. 2011). We are also interested in genetic manipulations of cyanobacteria and have recently established a method for in-vitro production of bi-parental plasmids (shuttle vectors) inherited  in E.coli and cyanobacteria. The in-vitro method of shuttle vector construction is applicable to virtually all prokaryotes propagating circular plasmids.            

4. Central molecular biology laboratory (CMBL)

The Institute for Limnology plans to centralize all molecular biological relevant devices and expertise in a central laboratory. In the CMBL experiments on all three levels of biomolecules (DNA, RNA and proteins) are performed. We are interested in collaborations with other scientists to share our expertise and especially students projects are highly welcome.
Projects

AplusB project  February 2011; tech2B Linz
Publications

2011

 Christiansen, G., Philmus, B., Hemscheidt, T., and Kurmayer, R. (2011) Genetic variation of adenylation domains of the anabaenopeptin synthesis operon and the evolution of substrate promiscuity. Journal of Bacteriology 193: 3822-3831 PDF
Kurmayer, R., Schober, E., Tonk, L., Visser, P., and Christiansen, G. (2011) Spatial divergence in the proportions of genes encoding toxic peptide synthesis among populations of the cyanobacterium Planktothrix in European lakes. FEMS Microbiol Letters 317:127-137. PDF

2010

 Christiansen, Guntram. patent application, August 2010, European patent office, Munich

2009

Kurmayer, R., and Christiansen, G. (2009): The genetic asis of toxin production in Cyanobacteria. Freshwater Reviews 2:31-50 PDF

Ishida, K., Welker, M., Christiansen, G., Cadel-Six, S., Bouchier, C., Dittmann, E., Hertweck, C., and Tandeau de Marsac, N. (2009) Plasticity and evolution of aeruginosin biosynthesis in cyanobacteria. Applied and Environmental Microbiology 75:2017-2026.

2008

Philmus, B., Christiansen, G., Yoshida, W.Y., and Hemscheidt, T.K. (2008) Posttranslational modification in microviridin biosynthesis. Chembiochem 9:3066-3073.

Christiansen, G., Yoshida W.Y., Blom, J., Portmann, C., Gademann, KG., Hemscheidt, T., and Kurmayer, R. (2008): Isolation and structure determination of two microcystins and sequence comparisons of McyABC adenylation domains in Planktothrix species. Journal of Natural Products 71:1881-1886. PDF Supplement

Christiansen G., Molitor C., Philmus B., and Kurmayer R. (2008): Non-toxic strains of cyanobacteria are the result of major gene deletion events induced by a transposable element. Molecular Biology and Evolution 25:1695-1704 Link

2007

Ishida K., Christiansen G., Yoshida WY., Kurmayer R., Welker , Bonjoch J., Hertweck C., Börner T., Hemscheidt T., and Dittmann E. (2007): Biosynthetic pathway and structure analysis of aeruginoside 126A and B, cyanobacterial peptide glycosides bearing an unusual 2-carboxy-6-hydroxyoctahydroindole moiety. Chemistry and Biology 14: 565-576. Links to PDF's (Ishida et al. 2007), (preface Ishida et al. 2007)

2006

Christiansen, G., Kurmayer, R., Liu, Q., Börner, T. (2006) Transposons inactivate the biosynthesis of the nonribosomal peptide microcystin in naturally occurring Planktothrix spp. Applied and Environmental Microbiology 72: 117-123. PDF, Cover

Sielaff, H.; Christiansen, G., and Schwecke (2006) T. Natural Products From Cyanobacteria: Exploiting a New Source for Drug Discovery. Idrugs. 9(2):119-127.

2005

Kurmayer R., Christiansen G., Gumpenberger M., and Fastner J. (2005): Genetic identification of microcystin ecotypes in toxic cyanobacteria of the genus Planktothrix . Microbiology 151: 1525-1533. PDF

Saker, M. L.; Fastner, J.; Dittmann, E.; Christiansen, G., and Vasconcelos, V. M. (2005) Variation Between Strains of the Cyanobacterium Microcystis Aeruginosa Isolated From a Portuguese River. Journal of Applied Microbiology. 99(4):749-757.

Tonk, L., Visser, P. M., Christiansen, G., Dittmann, E., Snelder, E., Wiedner, C., Mur, L. R., and Huisman, J. (2005) The Microcystin Composition of the Cyanobacterium Planktothrix Agardhii Changes Toward a More Toxic Variant With Increasing Light Intensity. Applied and Environmental Microbiology. 71(9):5177-5181.

2004

Kurmayer R., Christiansen G., Fastner J., and Börner T. (2004) Abundance of active and inactive microcystin genotypes in populations of the toxic cyanobacterium Planktothrix spp. Environmental Microbiology 6: 831-841. PDF, Cover

Welker, M.; Christiansen, G., and Von Dohren, H. (2004) Diversity of Coexisting Planktothrix (Cyanobacteria) Chemotypes Deduced by Mass Spectral Analysis of Microystins and Other Oligopeptides. Archives of Microbiology. 182(4):288-298.

2003

Christiansen, G., Fastner, J., Erhard, M., Borner, T., and Dittmann, E. (2003) Microcystin Biosynthesis in Planktothrix: Genes, Evolution, and Manipulation. Journal of Bacteriology. 185(2):564-572.

Hisbergues, M., Christiansen, G., Rouhiainen, L., Sivonen, K., and Borner, T. (2003) Pcr-Based Identification of Microcystin-Producing Genotypes of Different Cyanobacterial Genera. Archives of Microbiology. 180(6):402-410.

Kurmayer R., Christiansen G., and Chorus I. (2003): The abundance of microcystin-producing genotypes correlates positively with colony size in Microcystis and determines its microcystin net production in Lake Wannsee. Applied and Environmental Microbiology 69/2: 787-795. PDF

2001

Christiansen, G., Dittmann, E., Ordorika, L. V., Rippka, R., Herdman, M., and Borner, T. (2001) Nonribosomal Peptide Synthetase Genes Occur in Most Cyanobacterial Genera as Evidenced by Their Distribution in Axenic Strains of the Pcc. Archives of Microbiology. 176(6):452-458.

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