Identification of key effects causing weak performance of allergen analysis in processed food matrices

The weaker performance of generally used analytical methods for allergen analysis in processed foods can be connected to protein denaturation. To understand the nature of protein denaturation processes, experimental but realistic model matrices (corn starch based mixture, hydrated dough, and heat treated cookies) were developed that contain a defined amount of milk, egg, soy, and wheat proteins individually or in combination. The protein subunit composition was investigated in every processing phase, i.e. after mixing, dough formation, and baking. SDS-PAGE measurements were carried out to monitor the protein distribution of sample food matrices in non-reducing and reducing gels. The results clearly show that the highly decreased protein solubility is caused by denaturation, aggregation, or complex formation, which are the most significant factors in poorer analytical performances. Solubility can only partly be improved with the application of reducing agents or surfactants, and the rate of improvement is depending on the proteins and the matrices

Improving immersive experiences for visitors with sensory impairments to the aquarium of the pacific

This case study describes the development of a mid-air haptic solution to enhance the immersive experience of visitors who are deaf, blind or wheelchair users to the Aquarium of the Pacific's movie theatre. During the project we found that adding a sense of touch, using an innovative ultrasound technology, to an immersive experience can improve the sense of engagement users have with the content, and can help to improve agreement with the topics presented. We present guidelines on the design of haptic sensations. By describing how this project took place within the tight timelines of a commercial deployment, we hope to encourage more organisations to do similar work

Applicability of ELISA methods for high gluten-containing samples

Quantitation of gluten in gluten-free products is a great challenge as it is hindered by several factors including the lack of certified reference materials. To resolve this problem, our research group, in cooperation with other international experts, started a series of experiments with the goal of the production of a suitable gluten reference material. As a part of this research, several different wheat cultivars and their isolated gluten proteins were characterized by different methods, including enzyme-linked immunosorbent assay (ELISA). However, we need to know the performance of the ELISA methods used for this special area of research. During the present work we investigated the accuracy and precision of two different ELISA methods for our own laboratory conditions and special sample matrices (wheat flours and gliadin isolate). We have found that the tested performance characteristics of the methods seem to be appropriate on a case-by-case basis, but the long-term measurement uncertainty is higher, which makes it difficult to evaluate the results obtained with the ELISA method for these types of samples

Investigation of the effects of food processing and matrix components on the analytical results of ELISA using an incurred gliadin reference material candidate

Disorders induced by cereal proteins (e.g. wheat allergy, celiac disease) are widespread in human population. Since their only effective treatment is the avoidance of the problematic proteins, patients have to be familiar with the composition of food products. For checking special foods produced for them, proper analytical methods are necessary. At the moment, in gluten analysis there are no reference methods and reference materials which model real food matrices. During the production and experimental utilisation of our previously developed reference material candidate, numerous questions emerged. As our model product is a real food matrix, interactions can be present between gluten proteins and other macro and micro components. Fat content of the baked cookies is almost 20%, which might affect the results of ELISA measurements. The detectable gluten content is significantly increasing after the defatting procedure, as a pre-treatment of samples. Moreover, baking is a common food processing step that might modify the structure of gluten proteins leading to denaturation and aggregation. In the soluble protein fraction the amount of low molecular weight proteins increases, while that of high molecular weight proteins decreases during the baking procedure

8-Oxoguanine DNA glycosylase-1 links DNA repair to cellular signaling via the activation of the small GTPase Rac1

8-Oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant DNA base lesions induced by reactive oxygen species (ROS). Accumulation of 8-oxoG in the mammalian genome is considered a marker of oxidative stress, to be causally linked to inflammation, and is thought to contribute to aging processes and various aging-related diseases. Unexpectedly, mice that lack 8-oxoguanine DNA glycosylase-1 (OGG1) activity and accumulate 8-oxoG in their genome have a normal phenotype and longevity; in fact, they show increased resistance to both inflammation and oxidative stress. OGG1 excises and generates free 8-oxoG base during DNA base-excision repair (BER) processes. In the present study, we report that in the presence of the 8-oxoG base, OGG1 physically interacts with guanine nucleotide-free and GDP-bound Rac1 protein. This interaction results in rapid GDP→GTP, but not GTP→GDP, exchange in vitro. Importantly, a rise in the intracellular 8-oxoG base levels increases the proportion of GTP-bound Rac1. In turn Rac1-GTP mediates an increase in ROS levels via nuclear membrane-associated NADPH oxidase type 4. These results show a novel mechanism by which OGG1 in complex with 8-oxoG is linked to redox signaling and cellular responses

ELISA response and gliadin composition of different wheat cultivars grown in multiple harvest years

In special dietary products for people intolerant to gluten, gluten content is not supposed to exceed the regulatory thresholds. Enzyme-linked immunosorbent assays (ELISAs) are routinely used to quantitate gluten in these products. They measure gliadin/gluten with high specificity and sensitivity, but they have some limitations. Quantitative and qualitative variability of the target proteins among wheat cultivars is a factor that may cause inaccurate results. One of the aims of this work was to characterize the protein composition of five wheat cultivars grown in multiple harvest years and their blends by reversed-phase high-performance liquid chromatography (RP-HPLC). The gliadin/gluten content of these wheat flours was also analysed with two commercial ELISA kits. The effect of differences in protein profiles between the flours from an individual cultivar and the blend of five cultivars, harvest years, as well as processing procedures (dough forming and baking) on the results of two ELISA kits was investigated and their relative magnitude was determined. Among the factors investigated, the differences between flours had the greatest impact on gliadin recoveries

The transcription factor EGR2 is the molecular linchpin connecting STAT6 activation to the late, stable epigenomic program of alternative macrophage polarization

Macrophages polarize into functionally distinct subtypes while responding to microenvironmental cues. The identity of proximal transcription factors (TFs) downstream from the polarization signals are known, but their activity is typically transient, failing to explain the long-term, stable epigenomic programs developed. Here, we mapped the early and late epigenomic changes of interleukin-4 (IL-4)-induced alternative macrophage polarization. We identified the TF, early growth response 2 (EGR2), bridging the early transient and late stable gene expression program of polarization. EGR2 is a direct target of IL-4-activated STAT6, having broad action indispensable for 77% of the induced gene signature of alternative polarization, including its autoregulation and a robust, downstream TF cascade involving PPARG. Mechanistically, EGR2 binding results in chromatin opening and the recruitment of chromatin remodelers and RNA polymerase II. Egr2 induction is evolutionarily conserved during alternative polarization of mouse and human macrophages. In the context of tissue resident macrophages, Egr2 expression is most prominent in the lung of a variety of species. Thus, EGR2 is an example of an essential and evolutionarily conserved broad acting factor, linking transient polarization signals to stable epigenomic and transcriptional changes in macrophages