Aly Moussa

Calix[n]arenes as Protein Sensors

The use of calix[n]arene derivatives for the sensing of proteins is described. Initially the properties of the calix[n]arenes are described. In order to better understand how the calix[n]arenes may be used for protein sensors, a detailed survey of the interactions between the molecules and amino acids and peptide is presented. The known complexes between proteins and various calix[n]arene derivatives is described and the biological activity of the molecules summarised. The use of calix[n]arenes as protein sensors observed by Schrader using amphiphilic calix[n]arenes shows that these molecules may allow nanomolar sensing. The major section of the work deals with the development of a para-sulfonato-calix[n]arene-based system for the prion protein responsible for bovine spongiform encephalitis and variant-Creutzfeldt–Jacobs disease(v-CJD) in humans. Initially, the development of the test was based on a Western Blot detection, however, the need for large scale testing after the discovery that blood transfusion may lead to infection with v-CJD led to the transfer of the technology to an ELISA-based test.

Use of streptomycin for precipitation and detection of proteinase K resistant prion protein (PrPsc) in biological samples

The ability of streptomycin to form multimolecular aggregates with pathogenic prion proteins and their recovery by precipitation via a low-speed centrifugation step has been demonstrated; these novel properties of streptomycin make it a useful substance that increases the sensitivity of laboratory diagnostic techniques for prion infections in man and animals.

Enhanced detection of the pathogenic prion protein by its supramolecular association with para -sulfonato -calix[n]arene derivatives

The supramolecular interaction between the pathogenic form of the prion protein and derivatives of the para-sulfonato-calix[n]arenes has been demonstrated and two putative binding sites determined; this interaction leads to an amplification of the Western Blot immunological detection of the prion protein by the SAF84 antibody.

Amplified immunohistochemical detection of PrPsc in animal transmissible spongiform encephalopathies using streptomycin.

Due to its sensitivity, immunohistochemistry (IHC) of abnormal prion protein (PrPsc) is used to study experimental and natural cases of transmissible spongiform encephalopathies (TSEs) such as Creutzfeldt-Jakob disease in humans or scrapie and bovine spongiform encephalopathy (BSE) in animals. The limits of detection are particularly critical when PrPsc IHC is used for diagnostic purposes. In this article, we describe for the first time the use of streptomycin sulfate in IHC, providing a novel original and easy way to amplify specifically PrPsc immunohistochemical detection in natural cases of BSE and scrapie, as well as in experimental TSEs in mice models using two different PrP antibodies. (J Histochem Cytochem 54:849-853, 2006)

Prion early kinetics revisited using a streptomycin-based PrPres extraction method

The use of streptomycin in the PrP(sc) detection procedures represents a new and attractive way to detect more PrP(sc), the best marker for the transmissible spongiform encephalopathies (TSEs). Actually, the streptomycin PrP(sc) aggregating property reported recently was established as beneficial in PrP(sc) detection using immunohistochemistry in diagnostic as well as in experimental conditions. The present study reports in details how to use advantageously this original streptomycin property in PrP(res) biochemical extraction and detection. Using TSE diagnostic brain material, specificity and increased sensitivity using streptomycin-treated samples were substantiated. Then an early sequential brain and spleen sampling (from 7 to 49 days post-inoculation) from C57Bl/6 mice inoculated intra-cerebrally or intra-peritoneally with C506M3 scrapie strain was analysed using streptomycin versus ultracentrifugation PrP(res) extraction. Whatever the inoculation route, streptomycin allowed earlier PrP(res) detection in spleen (7 d.p.i.), then in brain suggesting a stronger affinity of the infectious agent for the lymphoid compartment.