Wild Allium species (Alliaceae) used in folk medicine of Tajikistan and Uzbekistan

BACKGROUND: Hitherto available sources from literature mentioned several wild growing Allium species as "edible" or "medicinally used" but without any further specification. METHODS: New data were gained during recent research missions: Allium plants were collected and shown to the local population which was asked for names and usage of these plants. RESULTS: Information was collected about current medical applications of sixteen wild species, nine of which belong to different sections of Allium subgenus Melanocrommyum. These plants are used against headache, cold, and stomach problems, and are mostly applied fresh or after boiling. CONCLUSION: Close taxonomic relatives of the common onion were used similar to cultivated onion species, but medical use like garlic was mostly reported for species taxonomically not related to garlic

Efficient determination of cysteine sulphoxides in Allium plants applying new biosensor and HPLC-MS² methods

Cysteine sulphoxide (CSO) contents of 16 different accessions of garlic (Allium sativum L.) and 15 varieties of onion (Allium cepa L.) were measured using two different rapid analytical methods: a biosensoric approach and a newly developed HPLC-MS2 technique. Both methods allow quantification of naturally occurring cysteine sulphoxides present in Allium plants without time-consuming sample pretreatment such as derivatisation of amino acid derivatives prior to HPLC-separation. It has been found that the amount of alliin, which is the predominant CSO occurring in garlic, varies between 0.2 and 2.2 g/100 g dry matter. Contrary to that, isoalliin representing the main CSO in onion has been detected in significantly lower amounts (0.3 to 1.25 g/100 g dry matter)

Detection of Salmonella by Surface Plasmon Resonance

This study explores the possibility of simultaneous and specific detection of Salmonella serovars by surface plasmon resonance (SPR). The Plasmonic® SPR device was used to develop this rapid assay. The sandwich immunoassay involves the use of a polyclonal anti-Salmonella antibody to simultaneous capture multiple Salmonella serovars present in a sample. This is followed by specific detection of the captured serovars using O-specific anti-Salmonella antibodies. Milk spiked with Salmonella Typhimurium and Salmonella Enteritidis was used as a model system to establish the assay. The assay was further extended to sequentially differentiate between the two Salmonella serovars on a single SPR chip in a single channel. The assay was proved to work without any additional dilution or clean-up steps. The sample volume requirement for the assay is only 10 μL. The lower limits of detection for Salmonella Typhimurium and Salmonella Enteritidis were 2.50×105 cells mL-1 and 2.50×108 cells mL-1, respectively

Covalent immobilisation of antibodies in Teflon-FEP microfluidic devices for sensitive quantification of clinically relevant protein biomarkers

This study reports for the first time sensitive colorimetric and fluorescence detection of clinically relevant protein biomarkers by sandwich immunoassays using covalent immobilisation of antibodies onto the fluoropolymer surface inside Teflon®-FEP microfluidic devices. Teflon®-FEP has outstanding optical transparency ideal for high-sensitivity colorimetric and fluorescence bioassays, however this thermoplastic is regarded as chemically inert and very hydrophobic. Covalent immobilisation can offer benefits over passive adsorption to plastic surfaces by allowing better control over antibody density, orientation and analyte binding capacity, and so we tested a range of different and novel covalent immobilisation strategies. We first functionalised the inner surface of a 10-bore, 200 µm internal diameter FEP microcapillary film with high-molecular weight polyvinyl alcohol (PVOH) without changing the outstanding optical transparency of the device delivered by the matched refractive index of FEP and water. Glutaraldehyde immobilisation was compared with use of photoactivated linkers and NHS-ester crosslinkers for covalently immobilising capture antibodies onto PVOH. Three clinically relevant sandwich ELISAs were tested, against the cytokine IL-1ß, the myocardial infarct marker cardiac troponin I (cTnI), and the chronic heart failure marker brain natriuretic peptide (BNP). Overall, glutaraldehyde immobilisation was effective for BNP assays, but yielded unacceptable background for IL-1ß and cTnI assays caused by direct binding of biotinylated detection antibody to the modified PVOH surface. We found NHS-ester groups reacted with APTES-treated PVOH coated fluoropolymer. This facilitated a novel method for capture antibody immobilisation onto fluoropolymer devices using a bifunctional NHS-maleimide crosslinker. The density of covalently immobilised capture antibodies achieved using PVOH/APTES/NHS/Maleimide approached levels seen with passive adsorption, and sensitive and quantitative assay performance was achieved using this method. Overall, PVOH coating provided an excellent surface for controlled covalent antibody immobilisation onto Teflon®-FEP for performing high-sensitivity immunoassays

Optimization of an Enzyme-based Multi-parameter Biosensor for Monitoring Biogas Processes

An enzyme-based multi-parameter sensor chip for the simultaneous measurement of formate, D- and L-lactate is presented. Thereby, the combination of a diaphorase (DIA) from Clostridium kluyveri with different NAD+-dependent dehydrogenases enables the specific recognition of each compound. The amperometric detection is performed via monitoring of the oxidation current of enzymatically produced hexacyanoferrate(II) at +300 mV vs. Ag/AgCl. Chemical cross-linking with glutaraldehyde is used for enzyme immobilization. Thereby, the sensor signal is investigated at different concentrations of the cross-linker in the enzyme membrane. The obtained results indicate that by optimization of the immobilization matrix, the sensor performance can be improved