Julian Weghuber

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Verified

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• Professor
• Group Leader at University of Applied Sciences Upper Austria

G-protein-coupled-receptor phosphorylation plays a major role in receptor desensitization and arrestin binding. It is, however, unclear how distinct receptor phosphorylation patterns may influence arrestin binding and subsequent trafficking. Here we engineer phosphorylation sites into the C-terminal tail of the β2-adrenoceptor (β2AR) and demonstrat...

Soft lithography-based contact printing techniques have evolved into versatile methods for creating micro- and nanoscale features of biomolecules on solid substrates. In this review we present the advances in soft lithography for biomolecule deposition and its applications in subcellular protein-protein interaction (PPI) analysis. We discuss variou...

Background/Objectives: Individuals with special metabolic demands are at risk of deficiencies in fat-soluble vitamins, which can be counteracted via supplementation. Here, we tested the ability of micellization alone or in combination with selected natural plant extracts to increase the intestinal absorption and bioefficacy of fat-soluble vitamins....

Datura stramonium and other nightshade plants commonly occur as weeds and have the potential to contaminate crops with toxic tropane alkaloids. Here, the contamination of soybeans with the tropane alkaloids atropine and scopolamine after co-harvesting with thornapple plants is reported. The potential route of contamination was found to be independe...

Citation: Ollinger, N.; Malachová, A.; Schamann, A.; Sulyok, M.; Krska, R.; Weghuber, J. Limited Effectiveness of Penicillium camemberti in Preventing the Invasion of Contaminating Molds in Camembert Cheese. Foods 2024, 13, 2865. https://doi.org/10.3390/ foods13182865 Academic Editors: Abstract: Mold-ripened cheese acquires a distinctive aroma and...

T cell receptor (TCR) clustering and formation of an immune synapse are crucial for TCR signaling. However, limited information is available about these dynamic assemblies and their connection to transmembrane signaling. In this work, TCR clustering is controlled via plug‐and‐play nanotools based on an engineered irreversible conjugation pair and a...

Diabetes mellitus is a spreading global pandemic. Type 2 diabetes mellitus (T2DM) is the predominant form of diabetes, in which a reduction in blood glucose uptake is caused by impaired glucose transporter 4 (GLUT4) translocation to the plasma membrane in adipose and muscle cells. Antihyperglycemic drugs play a pivotal role in ameliorating diabetes...

Plant extracts are increasingly recognized for their potential in modulating (postprandial) blood glucose levels. In this context, root extracts are of particular interest due to their high concentrations and often unique spectrum of plant bioactives. To identify new plant species with potential glucose-lowering activity, simple and robust methodol...

Bread is an important staple food that is susceptible to spoilage, making it one of the most wasted foods. To determine the safety of partially moldy bread, five types of bread were inoculated with common mold species. After incubation, the metabolite profile was determined in and under the inoculation spot, as well as at a lateral distance of 3 cm...

Palm oil has a bad reputation due to the exploitation of farmers and the destruction of endangered animal habitats. Therefore, many consumers wish to avoid the use of palm oil. Decorative sugar contains a small amount of palm oil to prevent the sugar from melting on hot bakery products. High-oleic sunflower oil used as a substitute for palm oil was...

Drosophila melanogaster, or the fruit fly, is widely used for modeling numerous human diseases, such as neurodegeneration, tumor development, cachexia, and intestinal dysfunction. It is a suitable model organism for research targeting the physiology and pathophysiology of the intestinal epithelial barrier and has also been used as a model organism...

Plant extracts rich in phytochemicals are known for their health benefits. Plant extract library from edible plants obtained from the region of Upper Austria was prepared. Food grade extraction procedures were applied, and relevant physico-chemical parameters measured. A focus on polyphenolic compounds revealed a significant correlation between the...

Numerous underexplored plant species are believed to possess considerable potential in combating oxidative stress and its associated health impacts, emphasizing the need for a comprehensive methodological screening approach to assess their antioxidant capacity. This study investigated 375 plant extracts, utilizing both cell-free and cellular method...

Cholesterol deposition in intimal macrophages leads to foam cell formation and atherosclerosis. Reverse cholesterol transport (RCT), initiated by efflux of excess cholesterol from foam cells, counteracts atherosclerosis. However, targeting RCT by enhancing cholesterol efflux was so far accompanied by adverse hepatic lipogenesis. Here, we aimed to i...

Many bioactive plant compounds, known as phytochemicals, have the potential to improve health. Unfortunately, the bioavailability and bioactivity of phytochemicals such as poly-phenolic flavonoids are reduced due to conjugation with sugar moieties. Here, we combine acid hydrolysis and tailored fermentation by lactic acid bacteria (Lactiplantibacill...

Biopolymers are very promising materials that find use in several industrial applications, ranging from packaging and food industry to the pharmaceutical and biomedical fields. Their main advantages include biocompatibility, biodegradability, non-toxicity and renewability. Despite all their great benefits,biopolymer foils also exhibit a few drawbac...

The potential of plant bioactives for the prevention and therapy of diabetes is increasingly being recognized. In the present study we investigated the antidiabetic properties of an aqueous Bistorta officinalis Delarbre extract (BODE) by employing both in-vitro assays and in-vivo models. Multiple targets in glucose homeostasis which are involved in...

Lipoprotein particles (LPs) are excellent transporters and have been intensively studied in cardiovascular diseases, especially regarding parameters such as their class distribution and accumulation, site-specific delivery, cellular internalization, and escape from endo/lysosomal compartments. The aim of the present work is the hydrophilic cargo lo...

Citrus bioflavonoids are widely studied for their potential to strengthen the intestinal barrier and to reduce oxidative damage. However, there is limited knowledge on the bioavailability of flavonoids and its impact on the antioxidant capacity of these nutrients in living organisms. For this study, we tested potential health-promoting effects of a...

Mould is a ubiquitous threat to safe food. In this work, a combination of three reliable methods to identify mould present in food at the species level is presented, to estimate the safety of the apparently non-moldy slices of bread and therefore contribute to the prevention of food waste. In overstored sliced bread, three mould species on the firs...

Membrane receptor clustering is fundamental to cell-cell communication; however, the physiological function of receptor clustering in cell signaling remains enigmatic. Here, we developed a dynamic platform to induce cluster formation of neuropeptide Y2 hormone receptors (Y2R) in situ by a chelator nanotool. The multivalent interaction enabled a dyn...

Intestinal absorption is intrinsically low for lipophilic micronutrients and phytochemicals. Plant extracts acting as bioavailability enhancers can complement for this deficiency by modulation of both, physicochemical and biochemical parameters, in the absorption process. However, these interactions often are limited to specific conditions and the...

Lignans are known to exhibit a broad spectrum of biological activities, indicating their potential as constituents of feed supplements. This study investigated two extracts derived from the feed supplements ‘ROI’ and ‘Protect’—which contain the wood lignans magnolol and honokiol (‘ROI’), or soluble tannins additional to the aforementioned lignans (...

Polymeric materials play an emerging role in biosensing interfaces. Within this regard, polymers can serve as a superior surface for binding and printing of biomolecules. In this study, we characterized 11 different polymer foils [cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polymethylmethacrylate (PMMA), DI-Acetate, Lumirror 4001, M...

At the plasma membrane of mammalian cells, major histocompatibility complex class I molecules (MHC-I) present antigenic peptides to cytotoxic T cells. Following the loss of the peptide and the light chain beta-2 microglobulin (β2m), the resulting free heavy chains (FHCs) can associate into homotypic complexes in the plasma membrane. Here, we invest...

Erucic acid is known to have negative effects on the human health and is therefore regulated in nutritional products such as vegetable oils. In order to determine the content of erucic acid in mustard oil an oil must be pressed from seeds, the oil derivatized into fatty acid methyl esters and then analyzed by gas chromatography. By using thermally...

Scope: Sea buckthorn (Hippophaes rhamnoides) is capable of ameliorating disturbed glucose metabolism in animal models and human subjects. Here, the effect of sea buckthorn oil as well as of extracts of fruits, leaves, and press cake on postprandial glucose metabolism is systematically investigated. Methods and results: Sea buckthorn did neither...

Depositing biomolecule micropatterns on solid substrates via microcontact printing (µCP) usually requires complex chemical substrate modifications to initially create reactive surface groups. Here, we present a simplified activation procedure for untreated solid substrates based on a commercial polymer metal ion coating (AnteoBindTM Biosensor reage...

Postprandial insulin-stimulated glucose uptake into target tissue is crucial for the maintenance of normal blood glucose homeostasis. This step is rate-limited by the number of facilitative glucose transporters type 4 (GLUT4) present in the plasma membrane. Since insulin resistance and impaired GLUT4 translocation are associated with the developmen...

Membrane receptors are central to cell-cell communication. Receptor clustering at the plasma membrane modulates physiological responses, and microscale receptor organization is critical for downstream signaling. Spatially restricted cluster formation of the neuropeptide Y 2 hormone receptor (Y 2 R) was observed in vivo ; however, the relevance of t...

Medicinal plant extracts are becoming increasingly important as an alternative for traditional drugs against diabetes mellitus (DM). For this reason, we initialized a target-based screening of 111 root extracts from an open access plant extract library (PECKISH) by ascertaining their in-vitro inhibitory efficacy on α-glucosidase. The two most activ...

Analysis of protein–protein interactions in living cells by protein micropatterning is currently limited to the spatial arrangement of transmembrane proteins and their corresponding downstream molecules. Here, we present a robust and straightforward method for dynamic immunopatterning of cytosolic protein complexes by use of an artificial transmemb...

Decreasing circulating low-density lipoprotein (LDL) cholesterol levels leads to decreased risk of cardio-vascular diseases. Natural compounds are capable of lowering LDL cholesterol even better than lifestyle modifications or medications. To identify novel plant-derived compounds to lower plasma LDL cholesterol levels, we performed high-content sc...

Bioactive plant compounds and extracts are of special interest for the development of pharmaceuticals. Here, we describe the screening of more than 1100 aqueous plant extracts and synthetic reference compounds for their ability to stimulate or inhibit insulin secretion. To quantify insulin secretion in living MIN6 β cells, an insulin-Gaussia lucife...

Type 2 diabetes mellitus (T2DM) is linked to insulin resistance and a loss of insulin sensitivity, leading to millions of deaths worldwide each year. T2DM is caused by reduced uptake of glucose facilitated by glucose transporter 4 (GLUT4) in muscle and adipose tissue due to decreased intracellular translocation of GLUT4-containing vesicles to the p...

Previously, we demonstrated that major histocompatibility complex class I molecules (MHC-I) that lose the antigenic peptide and the light chain beta-2 microglobulin (β 2 m) to become free heavy chains (FHCs) associate to form dimers or higher-order oligomers in the plasma membrane (Dirscherl et al., 2018). Here, we investigate this homotypic intera...

Analysis of protein-protein interactions in living cells by protein micropatterning is currently limited to the spatial arrangement of transmembrane proteins and their corresponding downstream molecules. Here we present a robust method for visual immunoprecipitation of cytosolic protein complexes by use of an artificial transmembrane bait construct...

For probing small distances in living cells, methods of super-resolution microscopy and molecular sensing are reported. A main requirement is low light exposure to maintain cell viability and to avoid photobleaching of relevant fluorophores. From this point of view, Structured Illumination Microscopy (SIM), Axial Tomography, Total Internal Reflecti...

Major histocompatibility complex class I molecules (MHC I) that lose the antigenic peptide and the light chain beta-2 microglobulin (β2m) to become free heavy chains at the cell surface are known to associate, forming oligomers on the plasma membrane that are insufficiently understood. Here, we investigate the homotypic interaction of MHC I free he...

Fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) are associated with digestive disorders and with diseases such as irritable bowel syndrome. In this study, we determined the FODMAP contents of bread, bakery products, and flour and assessed the effectiveness of sourdough fermentation for FODMAP reduction. The fermentation products...

Physiological‐relevant in vitro tissue models with their promise of better predictability have the potential to improve drug screening outcomes in preclinical studies. Despite the advances of spheroid models in pharmaceutical screening applications, variations in spheroid size and consequential altered cell responses often lead to nonreproducible a...

In the field of (food) toxicology, there is a strong trend of replacing animal trials with alternative methods for the assessment of adverse health effects in humans. The replacement of animal trials is not only driven by ethical concerns but also by the number of potential testing substances (food additives, packaging material, contaminants, and t...

Essential oils (EOs) have attracted increased interest for different applications such as food preservatives, feed additives and ingredients in cosmetics. Due to their reported variable composition of components, they might be acutely toxic to humans and animals in small amounts. Despite the necessity, rigorous toxicity testing in terms of safety e...

Due to the global rise of type 2 diabetes mellitus (T2DM) in combination with insulin resistance, novel compounds to efficiently treat this pandemic disease are needed. Screening for compounds that induce the translocation of glucose transporter 4 (GLUT4) from the intracellular compartments to the plasma membrane in insulin-sensitive tissues is an...

The physical microenvironment regulates cell behavior during tissue development and homeostasis. How single cells decode information about their geometrical shape under mechanical stress and physical space constraints within tissues remains largely unknown. Here, using a zebrafish model, we show that the nucleus, the biggest cellular organelle, fun...

The prevalence rates of obesity and type 2 diabetes have increased substantially in recent decades. Changes in lifestyle and diet are the first factors that need to be addressed. However, functional foods and food supplements containing fruit extracts and herbal products are also gaining increasing attention. In addition to identifying and quantita...

Here, we present a simple and robust experimental setup for the super-resolution live cell microscopy of membrane-proximal fluorophores, which is comparably easy to perform and to implement. The method is based on Structured Illumination Microscopy (SIM) with a switchable spatial light modulator (SLM) and exchangeable objective lenses for epi-illum...

This study was conducted to examine putative correlations between weather parameters during April-September and the amounts of nutrients, minerals and bioactive compounds in the juices of 16 apple varieties from four harvest years in Lower Austria. For most sugar-parameters, negative correlations were found with the total precipitation (r between -...

Recently, the application of herbal medicine for the prevention and treatment of diseases has gained increasing attention. Essential oils (EOs) are generally known to exert various pharmacological effects, such as antiallergic, anticancer, anti-inflammatory, and immunomodulatory effects. Current literature involving in vitro and in vivo studies ind...

Acrylamide is assumed to be a potential carcinogen, and reference values have therefore been implemented in EU legislation. Thus, the food industry needs to reduce the acrylamide content in consumer products to the lowest possible value. In this study, roasted rye was evaluated for its suitability as a coffee substitution product with respect to it...

Protein micropatterning is a powerful tool for spatial arrangement of transmembrane and intracellular proteins in living cells. The restriction of one interaction partner (the bait, e.g., the receptor) in regular micropatterns within the plasma membrane and the monitoring of the lateral distribution of the bait’s interaction partner (the prey, e.g....

Climatic changes and heat stress have become a great challenge in the livestock industry, negatively affecting, in particular, poultry feed intake and intestinal barrier malfunction. Recently, phytogenic feed additives were applied to reduce heat stress effects on animal farming. Here, we investigated the effects of ginseng extract using various in...

Mold identification at the species level in environmental samples is a major challenge. Molecular techniques have been widely used for fungal classification, but as most primers are genus-specific, it is laborious to identify unknown samples. In this study, a PCR-based method for the identification of mold at the species level was developed. Theref...

The transport of hydrophobic compounds to recipient cells is a critical step in nutrient supplementation. Here, we tested the effect of phospholipid-based emulsification on the uptake of hydrophobic compounds into various tissue culture cell lines. In particular, the uptake of ω-3 fatty acids from micellar or nonmicellar algae oil into cell models...

Peptide and protein micropatterns are powerful tools for the investigation of various cellular processes, including protein-protein interactions (PPIs). Within recent years, various approaches for the production of functional surfaces have been developed. Most of these systems use glass as a substrate, which has several drawbacks, including high fr...

Here, we report an accurate and versatile method for the simultaneous determination of 17 sugars (arabinose, erythrose, fructose, galactose, glucose, isomaltulose, lactose, lyxose, maltose, maltotriose, mannose, raffinose, rhamnose, ribose, sucrose, sorbose and xylose), seven polyols (erythritol, inositol, lactitol, maltitol, mannitol, sorbitol, an...

An increase in adipose tissue is caused by the increased size and number of adipocytes. Lipids accumulate in intracellular stores, known as lipid droplets (LDs). Recent studies suggest that parameters such as LD size, shape and dynamics are closely related to the development of obesity. Berberine (BBR), a natural plant alkaloid, has been demonstrat...

Guava (Psidium guajava) fruit extract prepared by supercritical CO2 extraction inhibits intestinal glucose resorption in a double-blind, randomized clinical study

Pharmaceutical agents or drugs often have some pronounced impact on protein-protein interactions in cells and, in particular, cell membranes. Changes of molecular conformations as well as of intermolecular interactions may affect dipole-dipole interaction between chromophoric groups, which can be proven by measurements of Förster Resonance Energy T...

Diabetes mellitus (DM) and consequential cardiovascular diseases lead to millions of deaths worldwide each year; 90% of all people suffering from DM are classified as Type 2 DM (T2DM) patients. T2DM is linked to insulin resistance and a loss of insulin sensitivity. It leads to a reduced uptake of glucose mediated by glucose transporter 4 (GLUT4) in...

Background and aims: Exchange of cholesterol between high-density lipoprotein (HDL) particles and cells is a key process for maintaining cellular cholesterol homeostasis. Recently, we have shown that amphiphilic cargo derived from HDL can be transferred directly to lipid bilayers. Here we pursued this work using a fluorescence-based method to dire...

Mol. Nutr. Food Res. 2018, 62, 1701012 DOI: 10.1002/mnfr.201701012 Phytochemicals can directly affect intestinal glucose uptake by competitive inhibition of sugar transporters. Anti‐hyperglycemic properties have been so far reported for guava leaves, but there is little understanding of guava fruit extracts in this context. Therefore, the effects o...

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Abstract: Scope: Known pharmacological activities of guava (Psidium guajava) include modulation of blood glucose levels. However, mechanistic details remain unclear in many cases. Methods and results: This study investigated the effects of different guava leaf and fruit extracts on intestinal glucose transport in vitro and on postprandial glucose l...

Elevated blood glucose levels in type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease, are caused by insulin resistance and β-cell failure. Various strategies, including the injection of insulin or the usage of insulin-sensitizing drugs, were pursued to treat T2DM or at least reduce the symptoms. In addition, the applicat...

Insulin-like growth factor-I receptor (IGF-IR) preferentially regulates the long-term IGF activities including growth and metabolisms. Kinetics of ligand-dependent IGF-IR endocytosis determines how IGF induces such downstream signaling outputs. Here we find that the insulin receptor substrate (IRS)-1 modulates how long ligand-activated IGF-IR remai...

Postprandial hyperglycemia is a serious risk factor for cardiovascular disease and type 2 diabetes mellitus (T2DM). As diet is a cornerstone of both T2DM prevention and therapy, we investigated the effects of various commercially available breads on postprandial glucose response and glycemic index. Furthermore, the impact of oilseed- and protein-en...

Insulin resistance and β cell failure are the main causes of elevated blood glucose levels in Type 2 diabetes mellitus (T2DM), a complex and multifactorial metabolic disease. Several medications to treat or reduce the symptoms of T2DM are used, including the injection of insulin and the application of insulin sensitizing or glucose production reduc...

Phytogenic feed additives represent a potential alternative to antibiotics with attributed health and growth promoting effects. Chickens supplemented with an essential oil blend, a Quillaja saponin blend or a combination of both phytogenic preparations showed a comprehensively and significantly improved apparent ileal digestibility of crude protein...

Characterization, especially quantification, of protein interactions in live cells is usually not an easy endeavor. Here, we describe a straightforward method to identify and quantify the interaction of a membrane protein (“bait”) and a fluorescently labeled interaction partner (“prey”) (membrane-bound or cytosolic) in live cells using Total Intern...