Synthesis and Characterization of Azido Plasticizer

In order to get a good compatibility with azidopolymers, plasticizers are required with a similar chemical structure. The energetic plasticizers EGBAA, DEGBAA, TMNTA and PETKAA were synthesized and characterized. They are liquid and the glass-transition temperatures are between −70.8°C and −34.1°C. The differential scanning calorimetry (DSC) analysis shows an acceptable thermal stability for practical applications. The infrared spectrum shows distinctly the functional groups C-N₃, ester, carbonyl and nitrate. The elemental analysis and NMR agree with the molecular structures. As a practical example, EGBAA was combined with the energetic binder Poly Nimmo. The viscosity, glass-transition point and stability of 50% mixtures were investigated.     

Identification of Mitochondrial DNA (NUMTs) in the Nuclear Genome of Daphnia magna

This is the first study in which the Daphnia magna (D. magna) nuclear genome (nDNA) obtained from the GenBank database was analyzed for pseudogene sequences of mitochondrial origin. To date, there is no information about pseudogenes localized in D. magna genome. This study aimed to identify NUMTs, their length, homology, and location for potential use in evolutionary studies and to check whether their occurrence causes co-amplification during mitochondrial genome (mtDNA) analyses. Bioinformatic analysis showed 1909 fragments of the mtDNA of D. magna, of which 1630 were located in ten linkage groups (LG) of the nDNA. The best-matched NUMTs covering >90% of the gene sequence have been identified for two mt-tRNA genes, and they may be functional nuclear RNA molecules. Isolating the total DNA in mtDNA studies, co-amplification of nDNA fragments is unlikely in the case of amplification of the whole tRNA genes as well as fragments of other genes. It was observed that TRNA-MET fragments had the highest level of sequence homology, thus they could be evolutionarily the youngest. The lowest homology was found in the D-loop-derived pseudogene. It may probably be the oldest NUMT incorporated into the nDNA; however, further analysis is necessary.     

Isolation and characterization of a major allergen in kiwi fruit

 The isolation of an important allergen in kiwi fruit (Actinidia chinensis) by ion-exchange chromatography (IEC) and micropreparative SDS-PAGE followed by electroelution is reported. The purity of the allergen was analysed by SDS-PAGE and immunoblotting with sera from patients who have an allergy to kiwi. The allergen was shown to have a molecular weight of 43 kDa by SDS-PAGE/immunoblotting and an isoelectric point of approximately 6.9 as estimated by IEC. In accordance with World Health Organization nomenclature, this allergen is called Act c 2. By immunoblot inhibition it was shown that epitopes from different allergens in kiwi fruit are also located on Act c 2. N-terminal amino acid sequencing of 17 amino acid residues did not reveal homology with the major allergens in birch pollen (Bet v 1), apple (Mal d 1) or with other proteins of allergenic plant foods. In addition, the isoelectric point of a 67-kDa allergen in kiwi fruit was estimated to be 7.4 by IEC, but micropreparative isolation of this allergen failed because of its very low content in the fruit. Received: 14 April 1997     

Super connectivity of line graphs

The super connectivity κ^′ and the super edge-connectivity λ^′ are more refined network reliability indices than connectivity κ and edge-connectivity λ. This paper shows that for a connected graph G with order at least four rather than a star and its line graph L(G), κ^′(L(G))=λ^′(G) if and only if G is not super-λ^′. As a consequence, we obtain the result of Hellwig et al. [Note on the connectivity of line graphs, Inform. Process. Lett. 91 (2004) 7] that κ(L(G))=λ^′(G). Furthermore, the authors show that the line graph of a super-λ^′ graph is super-λ if the minimum degree is at least three.     

Ultrathin-layer horizontal high-resolution two-dimensional electrophoresis of legume seed proteins with intermediate protein staining

Summary Legume seed proteins extracted with urea-containing buffer are fractionated by high-resolution 2D-electrophoresis (urea-IEF x pore gradient SDS-PAGE), both dimensions in horizontal ultrathin-layer polyacrylamide gel slabs. High reproducibility is obtained, because the first dimension is performed in a slab gel, where a large number of protein samples are separated under identical conditions. The gel of the first dimension (IEF) is fixed, stained with Coomassie Brilliant Blue G 250, and destained before application to the second-dimension gel (SDS-PAGE). Prestaining of the focused proteins does not alter the protein pattern obtained after SDS electrophoresis. Thus, bands are made visible before separation in the second dimension, and the amount of Ampholine in the dye front is reduced during electrophoresis. The first-dimension gels can easily be stored in the destaining solution until they are run in the second dimension. As the proteins are fixed in the gel, there is no loss of proteins and defocusing of bands due to diffusion during the SDS-equilibration procedure. Loading of the dimensionstable gel strip onto the second dimension gel is a very easy operation, since the ultrathin gel strip adheres to a plastic foil and is simply laid into a moulded gel through. The gel strip is not imbedded with polymerizing acrylamide or agarose solution like in the conventional gel-rod-techniques, because a very good surface contact is obtained between the two flat gels.

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Ultradiinnschicht horizontale, hochauflösende Zweidimensional-Elektrophorese von Leguminosensamen-Proteinen mit Protein-Zwischenfärbung

Zusammenfassung Mit harnstoffhaltigen Tris-Glycin-Puffer extrahierte Leguminosensamen-Proteine werden mit der hochauflösenden 2D-Elektrophorese (Harnstoff-IEF x Gradientengel-SDS-Elektrophorese) aufgetrennt, wobei beide Dimensionen in horizontalen ultradünnen, auf Folie polymerisierten Polyacrylamid-Flachgelen durchgeführt werden. Die Flachgel-Focussierung (1. Dimension) erlaubt die Trennung einer großen Anzahl von Proteinproben unter identischen Bedingungen, wodurch die Reproduzierbarkeit von 2D-Elektrophoresen erheblich verbessert wird. Das Gel der ersten Dimension (IEF) wird mit Coomassie BB G 250 gefdrbt, bevor die einzelnen Gelstreifen für die zweite Dimension (Gradientengel-SDS-Elektrophorese) verwendet werden. Dies hat den Vorteil, daß die focussierten Proteine bereits vor dem zweiten Trennungsschritt sichtbar gemacht und zudem die Trägerampholyte in der Farbstoff Front bei der SDS-Elektrophorese stark vermindert werden. Die vorgefärbten Focussierungsgele können problemlos in der Entfärbelösung für die SDS-Gradientengel-Elektrophorese aufbewahrt werden. Der Proteinverlust und die Banden-diffusion bei der SDS-Aquilibrierung werden durch die Fixierung im Focussierungsgel verhindert. Das 2-D-Proteinmuster wird durch das Vorfärben der focussierten Proteine nicht verdndert. Die dimensionsstabilen, auf Folie polymerisierten Focussierungsstreifen lassen sich einfach handhaben und müssen nicht wie Rundgele an die zweite Dimension aufpolymerisiert werden. Der Gel-Gel-Kontakt der beiden Flachgele ist ohne weitere Hilfsmaßnahmen ausgezeichnet.