Thomas Kroneis

Publications

• 9.87

  Impact points

  Accession-Specific Haplotypes of the Internal Transcribed Spacer Region in Arabidopsis thaliana - a Means for Barcoding Populations.

  Uwe K Simon, Slave Trajanoski, Thomas Kroneis, Peter Sedlmayr, Christian Guelly, Helmut Guttenberger

  Molecular biology and evolution. 03/2012;

  Eukaryote genomes contain multiple copies of nuclear ribosomal DNA (nrDNA) harbouring both highly conserved and variable regions. This has made nrDNA the most popular genetic marker for phylogenetic studies and the region of choice for barcoding projects. Furthermore, many scientists believe that al... [more] Eukaryote genomes contain multiple copies of nuclear ribosomal DNA (nrDNA) harbouring both highly conserved and variable regions. This has made nrDNA the most popular genetic marker for phylogenetic studies and the region of choice for barcoding projects. Furthermore, many scientists believe that all copies of nrDNA within one nucleus are practically identical due to concerted evolution. Here we investigate the model plant species Arabidopsis thaliana for intragenomic variation of the internal transcribed spacer region (ITS) of nrDNA. Based on a modified deep sequencing approach we provide a comprehensive list of ITS polymorphisms present in the two most widely used accessions of A. thaliana - Col-0 and Ler. Interestingly, we found that some polymorphisms are shared between these genetically very distinct accessions. On the other hand, the high number of accession-specific polymorphisms shows that each accession can be clearly and easily characterized by its specific ITS polymorphism patterns and haplotypes. Network analysis based on the detected haplotypes demonstrates that the study of ITS polymorphism patterns and haplotypes is an extremely powerful tool for population genetics. Using the methods proposed here it will now also be possible to extend the traditionally species-bound barcoding concept to populations.
• 6.26

  Impact points

  Combined molecular genetic and cytogenetic analysis from single cells after isothermal whole-genome amplification.

  Thomas Kroneis, Jochen B Geigl, Amin El-Heliebi, Martina Auer, Peter Ulz, Thomas Schwarzbraun, Gottfried Dohr, Peter Sedlmayr

  Clinical chemistry. 05/2011; 57(7):1032-41.

  Analysis of chromosomal aberrations or single-gene disorders from rare fetal cells circulating in the blood of pregnant women requires verification of the cells' genomic identity. We have developed a method enabling multiple analyses at the single-cell level that combines verification of the gen... [more] Analysis of chromosomal aberrations or single-gene disorders from rare fetal cells circulating in the blood of pregnant women requires verification of the cells' genomic identity. We have developed a method enabling multiple analyses at the single-cell level that combines verification of the genomic identity of microchimeric cells with molecular genetic and cytogenetic diagnosis. We used a model system of peripheral blood mononuclear cells spiked with a colon adenocarcinoma cell line and immunofluorescence staining for cytokeratin in combination with DNA staining with the nuclear dye TO-PRO-3 in a preliminary study to define candidate microchimeric (tumor) cells in Cytospin preparations. After laser microdissection, we performed low-volume on-chip isothermal whole-genome amplification (iWGA) of single and pooled cells. DNA fingerprint analysis of iWGA aliquots permitted successful identification of all analyzed candidate microchimeric cell preparations (6 samples of pooled cells, 7 samples of single cells). Sequencing of 3 single-nucleotide polymorphisms was successful at the single-cell level for 20 of 32 allelic loci. Metaphase comparative genomic hybridization (mCGH) with iWGA products of single cells showed the gains and losses known to be present in the genomic DNA of the target cells. This method may be instrumental in cell-based noninvasive prenatal diagnosis. Furthermore, the possibility to perform mCGH with amplified DNA from single cells offers a perspective for the analysis of nonmicrochimeric rare cells exhibiting genomic alterations, such as circulating tumor cells.

• Verification of the genomic identity of candidate microchimeric cells.

  Peter Sedlmayr, Thomas Kroneis

  Chimerism (Print). 01/2011; 2(3):63-64.

  Microchimerism has been studied in the context of a variety of diseases which include autoimmune diseases (such as systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus and autoimmune thyroid diseases), cancer (e.g., of the cervix, thyroid gland, lung, breast), tissue repair, transp... [more] Microchimerism has been studied in the context of a variety of diseases which include autoimmune diseases (such as systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus and autoimmune thyroid diseases), cancer (e.g., of the cervix, thyroid gland, lung, breast), tissue repair, transplantation and transfusion. It may become relevant in the context of cell-based non-invasive prenatal diagnosis. But how to safely identify individual microchimeric cells? This is a nontrivial question, for which a solution has recently been suggested.
• 1.91

  Impact points

  A new fine-needle aspiration system.

  Mathias Glehr, Andreas Leithner, Gerald Gruber, Paul Wretschitsch, Maximilian Zacherl, Thomas Kroneis, Franz Quehenberger, Reinhard Windhager

  Surgical innovation. 06/2010; 17(2):136-41.

  The main reasons for fine needle aspiration (FNA) failure are insufficient number of cells in the sample, nonrepresentative samples, and contamination of samples. The aim of this study was to measure the number of cells harvested by a new needle system with an aeration aperture (Thyrosampler) in com... [more] The main reasons for fine needle aspiration (FNA) failure are insufficient number of cells in the sample, nonrepresentative samples, and contamination of samples. The aim of this study was to measure the number of cells harvested by a new needle system with an aeration aperture (Thyrosampler) in comparison with a conventional FNA system (C-FNA). Under a double-blind setting, 30 aspirations, 15 with each system (C-FNA, Thyrosampler), were done in randomized order and recorded. The median total number of cells was 59 680 cells/mL with C-FNA and 396 400 cells/mL with Thyrosampler. The needle system with the aeration aperture led to a significantly higher cell amount (564% more cells than the conventional system; P < .005) in needle aspiration biopsy. The new system with the vacuum release feature leads to a significantly higher cell amount in needle aspiration biopsy, which is a well-defined benefit.
• 5.23

  Impact points

  Automatic retrieval of single microchimeric cells and verification of identity by on-chip multiplex PCR.

  Thomas Kroneis, Liat Gutstein-Abo, Kristina Kofler, Michaele Hartmann, Petra Hartmann, Marianna Alunni-Fabbroni, Wolfgang Walcher, Gottfried Dohr, Erwin Petek, Esther Guetta, Peter Sedlmayr

  Journal of cellular and molecular medicine. 06/2009;

  ABSTRACT The analysis of rare cells is not an easy task. This is especially true when cells representing a fetal microchimerism are to be utilized for the purpose of non-invasive prenatal diagnosis since it is both imperative and difficult to avoid contaminating the minority of fetal cells with mate... [more] ABSTRACT The analysis of rare cells is not an easy task. This is especially true when cells representing a fetal microchimerism are to be utilized for the purpose of non-invasive prenatal diagnosis since it is both imperative and difficult to avoid contaminating the minority of fetal cells with maternal ones. Under these conditions, even highly specific biochemical markers are not perfectly reliable. We have developed a method to verify the genomic identity of rare cells that combines automatic screening for enriched target cells (based on immunofluorescence labelling) with isolation of single candidate microchimeric cells (by laser microdissection and subsequent laser-catapulting) and low-volume on-chip multiplex PCR for DNA fingerprint analysis. The power of the method was tested by using samples containing mixed cells of related and non-related individuals. Single cell DNA fingerprinting was successful in 74% of the cells analyzed (55/74) with a PCR efficiency of 59.2% (860/1452) for heterozygous loci. The identification of cells by means of DNA profiling was achieved in 100% (12/12) of non-related cells in artificial mixtures and in 86% (37/43) of cells sharing a haploid set of chromosomes and was performed on cells enriched from blood and cells isolated from tissue. We suggest DNA profiling as a standard for the identification of microchimerism on a single cell basis.

• On-chip multiplex PCR identification of automatically retrieved single microchimeric cells

  Thomas Kroneis

  01/2009

  Degree: Dr. scient. med. (Ph.D.)

  Supervisor: Dr. Peter Sedlmayr / DDr. Erwin Petek

• DNA fingerprinting analysis of single cells via automated detection, laser microdissection, and low-volume on-slide PCR

  T Kroneis, Johannes T, M Alunni-Fabbroni, K Kofler, E Petek, G Dohr, P Sedlmayr

  Life Sciences 2008; 09/2008

• Contamination-free Analysis of Single Cells in Cell-based Non-invasive Prenatal Diagnosis

  T Kroneis, J Geigl, J Waldispühl-Geigl, M Alunni-Fabbroni, E Petek, W Walcher, G Dohr, P Sedlmayr

  The European Human Genetics Conference; 05/2008

• Towards contamination-free rare cell diagnosis

  T Kroneis, JB Geigl, J Waldispühl-Geigl, M Alunni-Fabbroni, E Petek, G Dohr, Sedlmayr P

  SAFE Final General Assembly Meeting; 05/2008

• Towards economically feasible cell-based non-invasive prenatal diagnosis

  P Sedlmayr, T Kroneis, K Kofler

  2nd Yazd International Student Award and Congress in Reproductive Medicine; 05/2007

• Slide-based Cytometry and Laser Microdissection in Non-Invasive Prenatal Diagnosis

  T Kroneis, K Kofler, T Havlicek, R Schmied, T Johannes, P. Sedlmayr

  4th European Congress of Reproductive Immunology; 07/2006