Mario Nenno

Publications

• Charakterisierung der Polytänchromosomen aus dem Embryosuspensor von Phaseolus coccineus L.

  Mario Nenno

  07/1998

  Degree: PhD

  Supervisor: PD Dr. H. Scherthan, Prof. Dr. H. J. Schmidt

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• 3.23

  Impact points

  Chromosomal localization and distribution of simple sequence repeats and the Arabidopsis-type telomere sequence in the genome of Cicer arietinum L.

  G Gortner, M Nenno, K Weising, D Zink, W Nagl, G Kahl

  Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology. 02/1998; 6(2):97-104.

  We used fluorescence in situ hybridization to probe the physical organization of five simple sequence repeat motifs and the Arabidopsis-type telomeric repeat in metaphase chromosomes and interphase nuclei of chickpea (Cicer arietinum L.). Hybridization signals were observed with the whole set of pro... [more] We used fluorescence in situ hybridization to probe the physical organization of five simple sequence repeat motifs and the Arabidopsis-type telomeric repeat in metaphase chromosomes and interphase nuclei of chickpea (Cicer arietinum L.). Hybridization signals were observed with the whole set of probes and on all chromosomes, but the distribution and intensity of signals varied depending on the motif. On root-tip metaphase chromosomes, CA and GATA repeats were mainly restricted to centromeric areas, with additional GATA signals along some chromosomes. TA, A and AAC repeats were organized in a more dispersed manner, with centromeric regions being largely excluded. In interphase nuclei of the inner integument, CA and GATA signals predominantly occurred in the heterochromatic endochromocentres, whereas the other motifs were found both in eu- and heterochromatin. The distribution of the Arabidopsis-type telomeric repeat (TTTAGGG)n on metaphase chromosomes was found to be quite exceptional. One major cluster of repeats was spread along the short arm of chromosome B, whereas a second, weaker signal occurred interstitially on chromosome A. Only faint and inconsistent hybridization signals were visualized with the same probe at the chromosomal termini.

• Chromosomal localization and distribution of simple sequence repeats

  Gortner G, Nenno M, Weising K, Zink D, Nagl W, Kahl G.

  Chromosome Res. 01/1998;
• 1.71

  Impact points

  Detection of rRNA and phaseolin genes on polytene chromosomes of Phaseolus coccineus by fluorescence in situ hybridization after pepsin pretreatment.

  M Nenno, K Schumann, W Nagl

  Genome / National Research Council Canada = Génome / Conseil national de recherches Canada. 01/1995; 37(6):1018-21.

  This is the first report of fluorescence in situ hybridization (FISH) on plant polytene chromosomes. Different protease pretreatments have been tested to improve fluorescence in situ hybridization FISH on polytene chromosomes of a plant, Phaseolus coccineus, with the aim to enable the detection of l... [more] This is the first report of fluorescence in situ hybridization (FISH) on plant polytene chromosomes. Different protease pretreatments have been tested to improve fluorescence in situ hybridization FISH on polytene chromosomes of a plant, Phaseolus coccineus, with the aim to enable the detection of low-copy genes. The structural preservation of the chromosomes and the distinctness of the FISH signals were comparatively analysed with a probe for the ribosomal RNA genes after digestion with pepsin and trypsin. The pepsin pretreatment resulted in a general loosening of chromatin with good conservation of chromosome morphology and an increased number and density of signal points. The six nucleolus organizers exhibited significant differences in condensation. The pretreatment with pepsin enabled the detection of the low-copy genes encoding the seed storage protein phaseolin.