Processing of the transmembrane glycoprotein (GP) of Marburg virus involved the conversion of an endo H-sensitive, ER-specific form into an endo H-resistant, Golgi-specific precursor that was cleaved into GP(1) and GP(2). Cleavage was mediated by furin or another subtilisin-like endoprotease with similar substrate specificity as indicated by mutational analysis of the cleavage site and inhibition using peptidyl chloromethylketones. Mature GP consisted of disulfide-linked GP(1) and GP(2) subunits.

Spodoptera frugiperda (Sf9) cells are widely employed for high-level expression of heterologous recombinant genes from baculovirus vectors. Using a plasmid library encoding cDNA of Sf9 cells we have identified here the Spodoptera frugiperda analog of the proprotein convertase furin which plays an important role in posttranslational protein processing. Spodoptera frugiperda furin (Sfurin) is closest related to Drosophila melanogasterfurin with which it shares an extended cysteine-rich domain, whereas mammalian furin shows high homology only in the catalytic domain. Mammalian furin and Sfurin were further compared by expression from baculovirus vectors. Substrate specificity and inhibitor profiles are identical for Sfurin and mammalian furin, whereas calcium-dependence, pH-optimum, and thermostability differ. Cleavage of recombinant influenza virus hemagglutinin was significantly enhanced in Sf9 cells after overexpression of Sfurin.

A micro-chamber for electrophoretic accumulation of charged biomolecules has been designed and evaluated. The system is based on a chip with an array of planar focusing electrodes. Particular attention was devoted to a design which enables penetration of a large sample volume by the electric field of the focusing electrodes. General design principles for a cylindrically symmetrical arrangement of the focusing electrodes were derived. Accumulation of DNA oligomers and streptavidin in aqueous solution was demonstrated. The concentration of biomolecules in the centre of the chip was enhanced by up to a factor of 200. The major fraction of the total charge delivered during electrophoretic accumulation results from Faradaic processes. The maximum charge density deliverable without visible gas formation was determined. By careful control of the voltage and current density applied to the electrodes, evolution of gas bubbles could be avoided for the time required to accumulate analyte molecules in the centre of the micro-chamber. On-chip electrophoretic accumulation of biomolecules can be applied to sample pre-conditioning in lab-on-a-chip devices for analysis of DNA and protein samples.

We have developed a genetic barcode module, based on a parallel sorting facility of single nucleotide polymorphism for secure individual identification of cattle. Biotinylated allelespecific oligonucleotides were immobilized onto the predefined spots of streptavidin tethered self-assembled monolayers with long chain alkanethiols on biochips. The target DNAs for hybridization and subsequent on-chip minisequencing were produced by multiplex PCR method. After enzymatic extension, only the moiety-modified dideoxynucleotide triphosphate, when coupled to its complementary target sequence, could be detected by the corresponding antibody to the moiety in a specific and sensitive manner. The database SNPZoo was developed for storage of the sequence information consisting of cytosine/thymidine patterns. This SNP chip system can further be used in the detection of any replaceable point mutations occurring in the human and animal genes.