Nucleic Acid Lateral Flow Immunoassay for the Detection of Pathogenic Bacteria from Food

Nucleic acid lateral flow immunoassay (NALFIA) is a method combining molecular biological principle of detection with immunochemical principle of visualisation. Following isolation of DNA from the sample, a duplex PCR with two primer sets, of which one was labelled with biotin and the other with digoxigenin or fluorescein, respectively, was performed. The PCR solution and carbon particles conjugated with avidin are directly added to the nitrocellulose membrane with two test lines of immobilised antibodies specific for digoxigenin and fluorescein. The appearance of a black line indicates the presence of specific amplicon. We would like to present the NALFIA for the simultaneous detection of L. monocytogenes in particular and the genus Listeria in general, in food. Bacteria from the genus Listeria frequently contaminate a large variety of foods. Occurrence of Listeria strains in food may indicate errors in good hygienic and manufacturing practice, only L. monocytogenes is a significant human and animal pathogen responsible for the serious illness listeriosis. Conventional microbiological methods for L. monocytogenes detection are laborious and take several days to achieve a confirmed identification

Colloidal carbon particles as a new label for rapid immunochemical test methods: quantitative computer image analysis of results

Colloidal carbon particles can serve as label in sol particle immunoassays. The universal applicability of these particles in qualitative and (semi)quantitative immunoassays has been demonstrated. Sol particle and/or dipstick immunoassays, not yet optimized in terms of sensitivity, are discussed.\ud \ud The colloidal label has been used successfully in a mouse immunoglobulin isotyping kit. Human serum albumin spotted onto nitrocellulose in a concentration range of 7.8 to 1000 ng could be detected using anti-albumin antibody adsorbed onto colloidal carbon particles. It was also possible to perform a competitive assay with this conjugate for a concentration range of free human serum albumin varying from 0.25 to 6.75 ¿g. The Kunitz-type trypsin inhibitor from soybean was determined by a colloidal carbon based immunoassay in a range of 2.5 to 160 ng. In this assay, free and colloidal carbon-bound inhibitor competed for binding specific antibodies spotted onto a nitrocellulose membrane.\ud \ud An image- and data-processing procedure has been developed that enables a rapid and simple quantification of colloidal carbon sol particle immunoassays. The average grey level of a spot is taken as a measure for quantitative purposes. This so-called Sol-particle Image Processed ImmunoAssay (SIPIA) procedure is equally well applicable to assays using other colloidal particles

A Quality Assurance Framework For Sulphonic Acid-Coated Sand Used In 3D Printing Applications

ArticleThe need for companies to adopt a quality management strategy has significantly increased in recent times as a result of global competition and more demanding customers. It is important to integrate quality throughout the product lifecycle, which includes the design phase. The purpose of the paper is to develop a quality assurance framework for the local production of chemical-coated sand used in the Voxeljet VX1000 printing process. The framework could be used as a basic structure to develop the necessary processes, procedures, and work instructions to ensure the quality of local chemical-coated sand

The arable ecosystem as battleground for emergence of new human pathogens

Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh) vegetables, sprouts, and occasionally fruits made clear that these pathogens are not only transmitted to humans via the “classical” routes of meat, eggs, and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure), water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals

Decrease of the IgE-binding by Mal d 1, the major apple allergen, by means of polyphenol oxidase and peroxidase treatments

Mal d 1, the major apple allergen, is heat labile and easily oxidized. Oxidative reactions catalyzed by polyphenol oxidase (PPO) and/or peroxidase (POD), present in apple, may be involved in decreasing its allergenicity. PPO and POD convert phenolic compounds into o-quinones. In this study the effect of PPO and POD, the polyphenol catechin and the antioxidant DIECA on IgE-binding by Mal d 1 was analyzed. Golden Delicious peel was selected for its high PPO and POD contents. IgE-binding was analyzed by competitive ELISA. IgE-binding by Mal d 1 decreased by adding oxidative enzymes, this decrease was most pronounced when PPO was used. Catechin induced a reduction in IgE binding when POD was used. The combination of catechin and PPO causes the strongest decrease of the allergenicity of Mal d 1. DIECA protected the IgE-binding by the allergen, protection being less strong in the presence of exogenous PPO and POD. The decrease of immunoreactivity is likely to be due to o-quinones, as active species or other intermediates modifying the tertiary structure of the allergens and cross-linking of the proteins, thus reducing their allergenicity

Implementing a business improvement model based on integrated plant information

The World Energy Council [1, 2] defines numerous challenges in the global energy arena that put pressure on owners and /operators to operate run existing plant better and more efficiently. As such there is an increasing focus on the use of business and technical plant information and data to make better, more integrated, and more informed decisions on the plant. The research study developed a business improvement model (BIM) that can be used to establish an integrated plant information management infrastructure as the core foundation for of business improvement initiatives. Operational research then demonstrated how this BIM approach could be successfully implemented to improve business operations and provide decision-making insightDie Wêreld Energie Raad [1, 2] definieer talle uitdagings in die wêreld energie arena wat aanleg eienaars en/of operateurs dwing om bestaande proses-aanlegte beter en meer doeltreffend te bestuur. Dit vereis toenemende fokus op besigheids- en tegniese aanleg inligting en data om beter, meer geïntegreerde en meer ingeligte besluite te neem. Die navorsingstudie het 'n besigheids-verbetering model ontwikkel wat gebruik kan word om 'n geïntegreerde aanleg inligting infrastruktuur te skep as die grondslag vir besigheid verbetering inisiatiewe. Operasionele navorsing is dan ook gebruik om prakties te demonstreer hoe hierdie model en benadering suksesvol geïmplementeer kan word om sakebedrywighede en besluitneming insig te verbete

Snelle toets tegen agressief snot in hyacint

PPO heeft een nieuwe toets beschikbaar die binnen een uur aangeeft of Dickeya (agressief snot) de oorzaak is van een snotbol. Telers en handelaren kunnen door deze versnelde diagnose eerder de juiste maatregelen nemen om schade door agressief snot te beperken