Alternaria alternata is a common fungus strongly related with severe allergic asthma, with 80% of affected individuals being sensitized solely to its major allergen Alt a 1. Here, we assessed the function of Alt a 1 as an innate defense protein binding to micronutrients, such as iron-quercetin complexes (FeQ2), and its impact on antigen presentation in vitro. Binding of Alt a 1 to FeQ2 was determined in docking calculations. Recombinant Alt a 1 was generated, and binding ability, as well as secondary and quaternary structure, assessed by UV-VIS, CD, and DLS spectroscopy. Proteolytic functions were determined by casein and gelatine zymography. Uptake of empty apo- or ligand-filled holoAlt a 1 were assessed in human monocytic THP1 cells under the presence of dynamin and clathrin-inhibitors, activation of the Arylhydrocarbon receptor (AhR) using the human reporter cellline AZ-AHR. Human PBMCs were stimulated and assessed for phenotypic changes in monocytes by flow cytometry. Alt a 1 bound strongly to FeQ2 as a tetramer with calculated Kd values reaching pico-molar levels and surpassing affinities to quercetin alone by a factor of 5000 for the tetramer. apoAlt a 1 but not holoAlta 1 showed low enzymatic activity against casein as a hexamer and gelatin as a trimer. Uptake of apo- and holo-Alt a 1 occurred partly clathrin-dependent, with apoAlt a 1 decreasing labile iron in THP1 cells and holoAlt a 1 facilitating quercetin-dependent AhR activation. In human PBMCs uptake of holoAlt a 1 but not apoAlt a 1 significantly decreased the surface expression of the costimulatory CD86, but also of HLADR, thereby reducing effective antigen presentation. We show here for the first time that the presence of nutritional iron complexes, such as FeQ2, significantly alters the function of Alt a 1 and dampens the human immune response, thereby supporting the notion that Alt a 1 only becomes immunogenic under nutritional deprivation.
- MeSH
- Allergens * MeSH
- Alternaria metabolism MeSH
- Asthma * MeSH
- Caseins MeSH
- Clathrin MeSH
- Humans MeSH
- Quercetin MeSH
- Iron metabolism MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Essential proteinogenic branched-chain amino acids (BCAA), particularly leucine (Leu) have been investigated for their role in enhancing human myofibrillar protein synthesis and biomedical research on tumor models. However, only a few protein sources in our current food system have high enough BCAA or Leu coefficients (% of total amino acids) to be considered as supplements for food, sport, or biomedical research. Mostly dairy-sourced proteins such as casein and whey or rarely plant source such as maize gluten are typically regarded as the gold standards. This study hypothesized that protein isolates derived from the whole-body homogenate (including the chitinous exoskeleton) of procambarid crayfish might exhibit unusually high BCAA and Leu content. The study provides open-access data on the amino acid compositions of two procambarid crayfish (Procambarus virginalis and P. clarkii), as well as a comparison with casein. The mentioned crayfish species could offer 6.36-7.39 g Leu 100 g-1 dry matter (at 43-48% protein only). Crayfish whole-body protein isolates exhibit a Leu coefficient (18.41±2.51% of total amino acids) and a BCAA coefficient (28.76±2.39% of total amino acids), which is comparable to or higher than of casein (Leu coefficient 8.65±0.08%; BCAA coefficient 20.03±0.73%). However, it is important to interpret these results with caution, due to the challenges associated with leucine and isoleucine separation, as well as potential interactions within the sample matrices. Hence, international validation of these findings is recommended. NOVELTY STATEMENT: Protein isolates from whole-body homogenate (including chitinous exoskeleton) of P. virginalis and/or P. clarkii are hypothesized to be dense in BCAA and Leu. For potential use in biomedical research or as additives in supplements for BCAA and Leu.
- MeSH
- Amino Acids metabolism MeSH
- Caseins MeSH
- Leucine MeSH
- Humans MeSH
- Astacoidea * metabolism MeSH
- Amino Acids, Branched-Chain * metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
We analyze the conditions of the adsorption of a flexible peptide onto a charged substrate in the 'wrong side' of the isoelectric point (WSIP), i.e. when surface and peptide charges have the same sign. As a model system, we focus on the casein macropeptide (CMP), both in the aglycosylated (aCMP) and fully glycosydated (gCMP) forms. We model the substrate as a uniformly charged plane while CMP is treated as a bead-and-spring model including electrostatic interactions, excluded volume effects and acid/base equilibria. Adsorption coverage, aminoacid charges and concentration profiles are computed by means of Monte Carlo simulations at fixed pH and salt concentration. We conclude that for different reasons the CMP can be adsorbed to both positively and negatively charged surfaces in the WSIP. For negatively charged surfaces, WSIP adsorption is due to the patchy distribution of charges: the peptide is attached to the surface by the positively charged end of the chain, while the repulsion of the surface for the negatively charged tail is screened by the small ions of the added salt. This effect increases with salt concentration. Conversely, a positively charged substrate induces strong charge regulation of the peptide: the acidic groups are deprotonated, and the peptide becomes negatively charged. This effect is stronger at low salt concentrations and it is more intense for gCMP than for aCMP, due to the presence of the additional sialic groups in gCMP.
- MeSH
- Adsorption MeSH
- Cytidine Monophosphate MeSH
- Isoelectric Point MeSH
- Caseins * MeSH
- Peptides * MeSH
- Surface Properties MeSH
- Publication type
- Journal Article MeSH
Cheeses are a group of fermented dairy products that are produced all over the world in various forms and flavours. Milk, especially sheep or goat milk, is still regarded as an expensive raw material in the world, which makes milk and milk products highly attractive as a fraud target. Most often, such fraud includes partial or complete substitution with cheaper sorts of milk (e.g. bovine milk). The aim of this work was to verify the authenticity of 27 cheeses commonly emerging on the Czech food market. The cheeses were distinguished on the basis of milk animal species origin. For this purpose, two mass spectrometry techniques were used: matrix-assisted laser desorption/ionization with time of flight mass spectrometry together with principal component analysis method and liquid chromatography coupled with electrospray ionization and quadrupole time-of-flight mass spectrometry. The results were a partial success, because the cheeses could only be partially distinguished with the first mass spectrometry technique probably because of the influence of some protein additive materials in cheeses. The second technique allowed for collecting higher quality results and thus appears to be highly suitable for the research task.
The cytopoxic effect of RL2 lactaptin (the recombinant analog of proteolytic fragment of human kappa-casein) toward tumor cells in vitro and in vivo presents it as a novel promising antitumor drug. The binding of any drug with serum proteins can affect their activity, distribution, rate of excretion and toxicity in the human body. Here, we studied the ability of RL2 to bind to various blood serum proteins. Using magnetic microparticles bearing by RL2 as an affinity matrix, in combination with mass spectrometry and western blot analysis, we found a number of blood serum proteins possessing affinity for RL2. Among them IgA, IgM and IgG subclasses of immunoglobulins, apolipoprotein A1 and various cortactin isoforms were identified. This data suggests that in the bloodstream RL2 lactaptin takes part in complicate protein-protein interactions, which can affect its activity.
- MeSH
- Chromatography, Affinity methods MeSH
- Caseins metabolism MeSH
- Blood Proteins analysis isolation & purification metabolism MeSH
- Polymethacrylic Acids chemistry MeSH
- Humans MeSH
- Magnets chemistry MeSH
- Microspheres MeSH
- Antineoplastic Agents metabolism MeSH
- Recombinant Proteins metabolism MeSH
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
In this study, a soil from two ceramic vessels belonging to Corded Ware culture, 2707⁻2571 B.C., found in a cremation grave discovered in Central Moravia, Czech Republic, was analyzed using matrix-assisted laser desorption/ionization⁻mass spectrometry (MALDI⁻MS) combined with advanced statistical treatment (principal component analysis, PCA, and orthogonal projection to latent structures discriminant analysis, OPLS-DA) and by enzyme-linked immunosorbent assay (ELISA). MALDI⁻MS revealed the presence of triacylglycerols in both vessels. This analytical technique was used for the analysis of the soil content from archaeological ceramic vessels for the first time. Targeted ELISA experiments consequently proved the presence of milk proteins in both ceramic vessels. These results represent the first direct evidence of the use of milk or dairy products in the Eneolithic period in Moravian Corded Ware Culture and help to better understand the diet habits and living conditions of Eneolithic populations in Central Europe.
Importance: Early exposure to complex dietary proteins may increase the risk of type 1 diabetes in children with genetic disease susceptibility. There are no intact proteins in extensively hydrolyzed formulas. Objective: To test the hypothesis that weaning to an extensively hydrolyzed formula decreases the cumulative incidence of type 1 diabetes in young children. Design, Setting, and Participants: An international double-blind randomized clinical trial of 2159 infants with human leukocyte antigen-conferred disease susceptibility and a first-degree relative with type 1 diabetes recruited from May 2002 to January 2007 in 78 study centers in 15 countries; 1081 were randomized to be weaned to the extensively hydrolyzed casein formula and 1078 to a conventional formula. The follow-up of the participants ended on February 28, 2017. Interventions: The participants received either a casein hydrolysate or a conventional adapted cow's milk formula supplemented with 20% of the casein hydrolysate. The minimum duration of study formula exposure was 60 days by 6 to 8 months of age. Main Outcomes and Measures: Primary outcome was type 1 diabetes diagnosed according to World Health Organization criteria. Secondary outcomes included age at diabetes diagnosis and safety (adverse events). Results: Among 2159 newborn infants (1021 female [47.3%]) who were randomized, 1744 (80.8%) completed the trial. The participants were observed for a median of 11.5 years (quartile [Q] 1-Q3, 10.2-12.8). The absolute risk of type 1 diabetes was 8.4% among those randomized to the casein hydrolysate (n = 91) vs 7.6% among those randomized to the conventional formula (n = 82) (difference, 0.8% [95% CI, -1.6% to 3.2%]). The hazard ratio for type 1 diabetes adjusted for human leukocyte antigen risk group, duration of breastfeeding, duration of study formula consumption, sex, and region while treating study center as a random effect was 1.1 (95% CI, 0.8 to 1.5; P = .46). The median age at diagnosis of type 1 diabetes was similar in the 2 groups (6.0 years [Q1-Q3, 3.1-8.9] vs 5.8 years [Q1-Q3, 2.6-9.1]; difference, 0.2 years [95% CI, -0.9 to 1.2]). Upper respiratory infections were the most common adverse event reported (frequency, 0.48 events/year in the hydrolysate group and 0.50 events/year in the control group). Conclusions and Relevance: Among infants at risk for type 1 diabetes, weaning to a hydrolyzed formula compared with a conventional formula did not reduce the cumulative incidence of type 1 diabetes after median follow-up for 11.5 years. These findings do not support a need to revise the dietary recommendations for infants at risk for type 1 diabetes. Trial Registration: clinicaltrials.gov Identifier: NCT00179777.
- MeSH
- Diabetes Mellitus, Type 1 epidemiology prevention & control MeSH
- Child MeSH
- Double-Blind Method MeSH
- Infant Nutritional Physiological Phenomena MeSH
- Caseins * MeSH
- Humans MeSH
- Infant Formula * MeSH
- Follow-Up Studies MeSH
- Infant, Newborn MeSH
- Disease-Free Survival MeSH
- Risk MeSH
- Nutrition Policy MeSH
- Check Tag
- Child MeSH
- Humans MeSH
- Male MeSH
- Infant, Newborn MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Multicenter Study MeSH
- Research Support, Non-U.S. Gov't MeSH
- Randomized Controlled Trial MeSH
- Research Support, N.I.H., Extramural MeSH
- Comparative Study MeSH
- MeSH
- Yogurt utilization MeSH
- Caseins MeSH
- Goats * MeSH
- Lactose MeSH
- Humans MeSH
- Milk, Human MeSH
- Milk Proteins MeSH
- Dairy Products * analysis classification utilization MeSH
- Milk * chemistry metabolism utilization MeSH
- Lactose Intolerance MeSH
- Mammals MeSH
- Cattle MeSH
- Statistics as Topic MeSH
- Cheese utilization MeSH
- Whey Proteins MeSH
- Check Tag
- Humans MeSH
- Cattle MeSH
Hydrophobins are small proteins that play a role in a number of processes during the filamentous fungi growth and development. These proteins are characterized by the self-assembly of their molecules into an amphipathic membrane at hydrophilic-hydrophobic interfaces. Isolation and purification of hydrophobins generally present a challenge in their analysis. Hydrophobin SC3 from Schizophyllum commune was selected as a representative of class I hydrophobins in this work. A novel procedure for selective and effective isolation of hydrophobin SC3 based on solid-phase extraction with polytetrafluoroethylene microparticles loaded in a small self-made microcolumn is reported. The tailored binding of hydrophobins to polytetrafluoroethylene followed by harsh elution conditions resulted in a highly specific isolation of hydrophobin SC3 from the model mixture of ten proteins. The presented isolation protocol can have a positive impact on the analysis and utilization of these proteins including all class I hydrophobins. Hydrophobin SC3 was further subjected to reduction of its highly stable disulfide bonds and to chymotryptic digestion followed by mass spectrometric analysis. The isolation and digestion protocols presented in this work make the analysis of these highly hydrophobic and compact proteins possible.
- MeSH
- Albumins chemistry MeSH
- Ananas chemistry MeSH
- Bromelains chemistry MeSH
- Canavalia chemistry MeSH
- Chymotrypsin chemistry MeSH
- Cytochromes c chemistry MeSH
- Disulfides chemistry MeSH
- Erythrocytes enzymology MeSH
- Solid Phase Extraction methods MeSH
- Mass Spectrometry methods MeSH
- Carbonic Anhydrases chemistry MeSH
- Caseins chemistry MeSH
- Horses MeSH
- Concanavalin A chemistry MeSH
- Chickens MeSH
- Humans MeSH
- Microspheres * MeSH
- Milk enzymology MeSH
- Myocardium metabolism MeSH
- Polytetrafluoroethylene chemistry MeSH
- Proteomics methods MeSH
- Schizophyllum chemistry MeSH
- Cattle MeSH
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization MeSH
- Tandem Mass Spectrometry MeSH
- Thermolysin chemistry MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
