Rapid identification of a tobacco mosaic virus epitope by using a coat protein gene-fragment-pVIII fusion library

This study describes the identification of the epitope recognized by the tobacco mosaic virus (TMV) coat protein (CP)-specific monoclonal antibody 29 (MAb29) by displaying a CP gene-fragment library on pVIII of filamentous phage M13. More than 80 per cent of the clones isolated after one round of panning bound specifically to MAb29. DNA sequencing of ten randomly chosen MAb29-specific clones and subsequent sequence comparison revealed a common seven amino acid epitope (ELIRGTG) representing amino acids 131-137 of the TMV CP. The reactivity of MAb29 in competition ELISA towards glutathione S-transferase fused to this epitope was stronger than that towards full-length wild-type TMV CP, confirming the epitope sequence determined by gene-fragment phage display. This demonstrated that gene-fragment libraries displayed on the phage surface as fusion proteins with the filamentous bacteriophage gene VIII are useful tools for rapid identification of linear epitopes recognized by MAbs

Characterization and dynamic behavior of wild yeast during spontaneous wine fermentation in steel tanks and amphorae

We studied the dynamic behavior of wild yeasts during spontaneous wine fermentation at a winery in the Valais region of Switzerland. Wild yeasts in the winery environment were characterized using a PCR-RFLP method. Up to 11 different yeast species were isolated from the vineyard air, whereas only seven were recovered from the grapes surface. We initially investigated a cultureindependent method in pilot-scale steel fermentation tanks and found a greater diversity of yeasts in the musts from two red grape varieties compared to three white grape varieties. We found that the yeasts Metschnikowia pulcherrima, Rhodotorula mucilaginosa, Pichia kluyveri, P. membranifaciens and Saccharomyces cerevisiae remained active at the end of the fermentation. We also studied the dynamic behavior of yeasts in Qvevris for the first time using a novel, highlysensitive quantitative real-time PCR method. We found that non-Saccharomyces yeasts were present during the entire fermentation proces s, with R. mucilaginosa and P. anomala the most prominent species. We studied the relationship between the predominance of different species and the output of the fermentation process. We identified so-called spoilage yeasts in all the fermentations, but high levels of acetic acid accumulated only in those fermentations with an extended lag phase

Rapid detection of human anti-HCV immunoglobulins on electrical biochips

The detection of hepatitis C virus (HCV) in the blood of patients is currently based on immunological assays (enzyme-linked immunosorbent assay [ELISA] and recombinant immunoblot assay) that use different HCV epitopes to detect anti-HCV antibodies, and these tests usually require laboratories and trained personnel. The ELISA-based systems are also time consuming. Portable diagnostic devices offering rapid test results would therefore be advantageous in the field of medical care. To facilitate the fast and reliable diagnosis of HCV, we used a miniaturized automated system based on a cartridge with an integrated electrical biochip for the decentralized detection of anti-HCV antibodies against the Core, NS3, and NS4A proteins. This system allows the detection of virus-specific antibodies in 2 µL of serum or whole blood within 15 minutes using an ELISA directly on a gold electrode array containing HCV proteins as the capture antigen. The sensitivity of this system is comparable with standard microtiter plate ELISAs, but the duration of the novel assay is 5%–6% that of standard ELISAs