Ultrastructural analysis of chromatin in meiosis I plus II of rye (Secale cereale L.)

Scanning electron microscopy (SEM) proves to be an appropriate technique for imaging chromatin organization in meiosis I and II of rye (Secale cereale) down to a resolution of a few nanometers. It could be shown for the first time that organization of basic structural elements (coiled and parallel fibers, chromomeres) changes dramatically during the progression to metaphase I and II. Controlled loosening with proteinase K (after fixation with glutaraldehyde) provides an enhanced insight into chromosome architecture even of highly condensed stages of meiosis. By selective staining with platinum blue, DNA content and distribution can be visualized within compact chromosomes as well as in a complex arrangement of fibers. Chromatin interconnecting threads, which are typically observed in prophase I between homologous and non-homologous chromosomes, stain clearly for DNA. In zygotene transversion of chromatid strands to their homologous counterparts becomes evident. In pachytene segments of synapsed and non-synapsed homologs alternate. At synapsed regions pairing is so intimate that homologous chromosomes form one filament of structural entity. Chiasmata are characterized by chromatid strands which traverse from one homolog to its counterpart. Bivalents are characteristically fused at their telomeric regions. In metaphase I and II there is no structural evidence for primary and secondary constrictions. Copyright (C) 2003 S. Karger AG, Basel

Mutual dependencies : ‘change’ and ‘discourse’

status: publishe

Cultivation and analysis of anthocyanin containing types of potatoes in organic farming regarding cultivability and additional health benefits

In a two year research project a representative spectrum of blue potato varieties were cultivated and tested in detail regarding disease infestation, yield potential and the influence of production systems (organic). Cultivation recommendations for blue potatoes could be deduced from this. Furthermore the varying anthocyanin content as well as the antioxidant capacity of the varieties used was analysed. Varieties with a particularly high content will undergo further tests to show the influence of the manner of preparation (boiling, steaming, frying) and determine their use for the processing industry. The combination of ecologically produced potatoes with „additional health benefits“ arouses the customers interest. The cultivation of high yield blue types can be an alternative to the cultivation of yellow fleshed high yield varieties in organic operating companies

Parceria Embrapa - Forschungszentrum Jülich (IBG-2) programa Labex Europa/Alemanha, em novos métodos não-invasivos aplicados a fenotipagem de plantas.

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Computing performability for wireless sensor networks

The performability of a wireless sensor network (WSN) can be measured using a range of metrics, including reliability (REL) and expected hop count (EHC). EHC assumes each link has a delay value of 1 and devices have no delay or vice versa, which is not necessarily appropriate for WSNs. This paper generalizes the EHC metric into an expected message delay (EMD) that permits arbitrary delay values for both links and devices. Further, it proposes a method based on Augmented Ordered Multivariate Decision Diagram (OMDD-A) that can be used to compute REL, EHC and EMD for WSN with both device and link failures. Simulation results on various networks show the benefits of the OMDD-A approach

Using multi-valued decision diagram to solve the expected hop count problem

The Expected Hop Count (EHC) of a computer communication network has so far been computed for network models that consider only device or link failure, but not both. We introduce an Augmented Ordered Multi-valued Decision Diagram (OMDD-A) to obtain the EHC of a network in which both devices and links may fail. The OMDD-A approach can compute the EHC of a 2100 grid network with 299 paths, which is unsolvable using existing techniques. We show that OMDD-A generates significantly fewer nodes than the corresponding ordered binary decision diagram, leading to large reductions in processing time

Systemic shRNA mediated knock down of S100A4 in colorectal cancer xenografted mice reduces metastasis formation

The metastasis-inducing protein S100A4 was found to be a prognostic indicator for the development of metachronous metastases. S100A4 expression levels correlate with the formation of human colorectal cancer metastases and shorter patients' survival. Inhibition of S100A4 expression in patients might therefore result in decreased metastasis formation and prolonged survival. In the present study, we used shRNA expression plasmids to inhibit S100A4 expression in the colorectal cancer cell lines HCT116, SW620 and DLD-1. Cell lines with reduced S100A4 expression showed reduced cell migration and invasion in vitro. The knock-down of S100A4 expression also led to significantly diminished formation of liver metastases when intrasplenically transplanted in mice (P = 0.004). We then focused on the therapeutic potential of systemically applied shRNA expression plasmids acting on S100A4 via repeated hydrodynamics-based tail vein injection of plasmid DNA. Mice, intrasplenically transplanted with HCT116 cells and treated systemically with S100A4‑shRNA plasmids, showed a decrease of S100A4 and MMP9 expression levels, resulting in significantly reduced liver metastases (P = 0.005). In summary, we show for the first time the intratumoral knock down of S100A4 via systemic application of S100A4‑shRNA plasmid DNA, which restricts metastasis formation in a xenografted mouse model of colorectal cancer

Transmission of grapevine viroids is not likely to occur mechanically by normal pruning

In epidemiological studies the viroid distribution in two local vineyards was determined. Grapevine leaves of different varieties were collected, total RNA isolated and viroid detected by northern blot analysis and/or reverse transcription followed by PCR amplification. Nearly each sample was infected with the grapevine variant of Hop Stunt Viroid and approximately each second additionally with Grapevine Yellow Speckle Viroid 1. Grapevine Yellow Speckle Viroid 2, a third grapevine viroid, was not found. Both grapevine viroids occurred in chlorotic plants as well as in plants without symptoms. In order to investigate viroid spreading through mechanical transmission accomplished during routine cultural practices, the distribution patterns in the two vineyards were analysed. Our results indicate that grapevine viroids are mainly propagated through systemic transmission upon grafting. The examination of different rootstock clones from Northern Italy, which are used for grafting in Germany, further demonstrates that in this case propagation is not due to rootstocks containing viroid but is more likely to occur via infected scion varieties