Untersuchungen zur Variabilität verschiedener Merkmale beim Raps und ihre Auswirkungen auf züchterische Maßnahmen

Ohne ZusammenfassungMit 5 Abbildungen     

Characterization and regional mapping of new anonymous chromosome 20-specific DNA markers isolated from a flow-sorted DNA library

Employing the flow-sorted chromosome 20-specific DNA library LL20NS01, we isolated seven novel unique poly- and monomorphic DNA markers specific to human chromosome 20. Initially, 201 phage clones were analyzed regarding insert size and repetitivity. By testing 14 single- and low-copy number clones for their ability to detect RFLPs, three polymorphisms were revealed by two probes, pFMS22-1.4 [D20S22] and pFMS76 [D20S23]. Seven of twenty probes (35%) were assigned to chromosome 20 using a somatic cell hybrid DNA panel. Five of them were regionally mapped by in situ hybridization. Three DNA markers, pFMS51 [D20S29], pFMS76 [D20S23], and pFMS106 [D20S30], were assigned to 20p11.2-p12, and two markers, pFMS22-1.4 [D20S22] and pFMS135 [D20S31], to 20q12-q13.3. Our new chromosome 20-specific DNA markers should be useful for the molecular characterization of this rather underpopulated human chromosome.     

Seasonal variation in catabolic enzyme activities in breast muscle of some migratory birds

Summary Five bird species were examined in order to ascertain if any changes in flight muscle catabolism take place between breeding season and migration. Two different patterns were discovered. The first consists of a high oxidative capacity and a low glycolytic and anaerobic capacity during migration. The converse occurs during the breeding season, i.e. low oxidative, high glycolytic and anaerobic capacity. The pattern was found in those species that deposit large amounts of fat prior to migration. The second pattern was similar to the first, but there was no change in fatty acid oxidation capacity between breeding season and migration. The pattern was found in those species that do not deposit much fat towards migration. These changes are believed to reflect differences in migration strategy and differences in locomotory activity during different seasons. Deviations from these patterns are discussed.     

Terpen-derivate aus Senecio-arten

Investigation of about 50 Senecio species has afforded many new substances, in addition to known compounds. Present in these plants are 23 fura     

Distribution and cellular localization of caldendrin immunoreactivity in adult human forebrain.

We investigated by immunohistochemistry (IHC) the distribution of caldendrin, the founding member of a novel family of neuronal calcium-binding proteins closely related to calmodulin, in human forebrain. Caldendrin immunoreactivity was unevenly distributed, with prominent staining in the paleo- and neocortex, hippocampus, and hypothalamus. With the exception of the hypothalamus, labeling was restricted to the somato-dendritic compartment of neurons. This distribution completely matches that reported in rat, indicating that the cellular function is most likely conserved among species. Therefore, one prerequisite for functional studies in rodent models aimed at elucidation of mechanisms with relevance for humans can be based on the present findings.     

Evolutionary history of the genus Listeria and its virulence genes

The genus Listeria contains the two pathogenic species Listeria monocytogenes and Listeria ivanovii and the four apparently apathogenic species Listeria innocua, Listeria seeligeri, Listeria welshimeri, and Listeria grayi. Pathogenicity of the former two species is enabled by an approximately 9 kb virulence gene cluster which is also present in a modified form in L. seeligeri. For all Listeria species, the sequence of the virulence gene cluster locus and its flanking regions was either determined in this study or assembled from public databases. Furthermore, some virulence-associated internalin loci were compared among the six species. Phylogenetic analyses were performed on a data set containing the sequences of prs, ldh, vclA, and vclB (all directly flanking the virulence gene cluster), as well as the iap gene and the 16S and 23S-rRNA coding genes which are located at different sites in the listerial chromosomes. L. grayi represents the deepest branch within the genus. The remaining five species form two groupings which have a high bootstrap support and which are consistently found by using different treeing methods. One lineage represents L. monocytogenes and L. innocua, while the other contains L. welshimeri, L. ivanovii and L. seeligeri, with L. welshimeri forming the deepest branch. Based on this perception, we tried to reconstruct the evolution of the virulence gene cluster. Since no traces of lateral gene transfer events could be detected the most parsimonious scenario is that the virulence gene cluster was present in the common ancestor of L. monocytogenes, L. innocua, L. ivanovii, L. seeligeri and L. welshimeri and that the pathogenic capability has been lost in two separate events represented by L. innocua and L. welshimeri. This hypothesis is also supported by the location of the putative deletion breakpoints of the virulence gene cluster within L. innocua and L. welshimeri.     

The receptor-like MLO protein and the RAC/ROP family G-protein RACB modulate actin reorganization in barley attacked by the biotrophic powdery mildew fungus Blumeria graminis f.sp. hordei

Cytoskeleton remodelling is a crucial process in determining the polarity of dividing and growing plant cells, as well as during interactions with the environment. Nothing is currently known about the proteins, which regulate actin remodelling during interactions with invading pathogens. The biotrophic powdery mildew fungus Blumeria graminis f.sp. hordei (Bgh) invades susceptible barley (Hordeum vulgare L.) by penetrating epidermal cells, which remain intact during fungal development. In contrast, resistant host plants prevent infection by inhibiting penetration through apoplastic mechanisms, which require focusing defence reactions on the site of attack. We stained actin filaments in a susceptible Mlo-genotype and a near-isogenic race-non-specifically resistant barley mlo5-mutant genotype using fluorescence-labelled phalloidin after chemical fixation. This revealed that the actin cytoskeleton is differentially reorganized in susceptible and resistant hosts challenged by Bgh. Actin filaments were polarized towards the sites of attempted penetration in the resistant host, whereas when susceptible hosts were penetrated, a more subtle reorganization took place around fungal haustoria. Strong actin filament focusing towards sites of fungal attack was closely associated with successful prevention of penetration. Actin focusing was less frequent and seemingly delayed in susceptible wild-type barley expressing the susceptibility factor MLO. Additionally, single cell overexpression of a constitutively activated RAC/ROP G-protein, CA RACB, another potential host susceptibility factor and hypothetical actin cytoskeleton regulator, partly inhibited actin reorganization when under attack from Bgh, whereas knockdown of RACB promoted actin focusing. We conclude that RACB and, potentially, MLO are host proteins involved in the modulation of actin reorganization and cell polarity in the interaction of barley with Bgh.