Development of high sensitive real-time PCR to detect mustard and other allergens of the family Brassicaceae in food samples

Mustard is a commonly used condiment including in production of other food products. As mustard is an allergen, it is necessary to control its presence. The development of PCR test-systems for its detection is complicated by the fact that this condiment can be made from seeds of various plant species (Brassica juncea, Brassica nigra, Sinapis alba) of the family Brassicaceae that are not closely related. This family includes other plant species such as white cabbage (Brassica oleracea) and rapeseed (Brassica napus), which can cause the allergic reaction, although seldom. In this connection, many authors use primers specific to many species of this family, including to allergens, to detect mustard. In this work, we used the similar strategy. To increase sensitivity, primers for the mitochondrial COX gene were selected. To increase PCR stability in analysis of deeply processed products, primers were selected for a region with a length of 61 base pair. In the work, the specificity and sensitivity of the developed PCR method was confirmed. Analyses of different products, including those that underwent deep technological processing, were carried out with these primers. Also, primers were selected to detect white mustard (S. alba). When analyzing products on the presence of white mustard, charac‑ teristic regional preferences were demonstrated: this species is used in manufacturing products mainly in the UK and USA

Quantum phase transition in a two-dimensional system of dipoles

The ground-state phase diagram of a two-dimensional Bose system with dipole-dipole interactions is studied by means of quantum Monte Carlo technique. Our calculation predicts a quantum phase transition from gas to solid phase when the density increases. In the gas phase the condensate fraction is calculated as a function of the density. Using Feynman approximation, the collective excitation branch is studied and appearance of a roton minimum is observed. Results of the static structure factor at both sides of the gas-solid phase are also presented. The Lindeman ratio at the transition point comes to be $\gamma = 0.230(6)$. The condensate fraction in the gas phase is estimated as a function of the density.Comment: 4 figures v.3 One citation added, updated Fig.4. Minor changes following referee's and editor's comment

Multiplex Real-Time PCR with HRM for Detection of Lactobacillus sakei and Lactobacillus curvatus in Food Samples

SAŽETAK Za optimiranje procesa potrebno je pratiti sastav starter kulture i njezin rast tijekom fermentacije. Većina starter kultura sadržava srodne mikroorganizme. U današnje se vrijeme za identifikaciju većeg broja srodnih vrsta često upotrebljava postupak analize krivulje mekšanja DNK visoke razlučivosti. Stoga je u radu za detekciju i razlikovanje bakterija Lactobacillus sakei i L. curvatus upotrijebljena lančana reakcija polimeraze (PCR) u stvarnom vremenu, te je provedena analiza krivulje mekšanja DNK visoke razlučivosti. Odabran je par početnica za ciljano mjesto vezivanja u genu rpoA, izoliranom iz bakterija roda Lactobacillus spp. S tim je parom početnica uspješno ispitano 1 1 starter kultura i 15 uzoraka fermentiranih kobasica poznatog sastava bakterija.Optimization of fermentation processes requires monitoring the species composition of starter cultures and their growth during fermentation. Most starter cultures contain closely related species. Nowadays, high-resolution melting (HRM) analysis is extensively used for multiplex identification of closely related species. In the present paper, we applied real-time polymerase chain reaction (PCR) with HRM analysis for the detection and differentiation of Lactobacillus sakei and L. curvatus. A primer pair was selected for the site of the rpoA gene of Lactobacillus spp. Eleven starter cultures and fifteen fermented sausages with a known bacterial composition were successfully tested using real-time PCR with HRM analysis with the developed primer pair