The protein structure determines the sensitizing capacity of Brazil nut 2S albumin (Ber e1) in a rat food allergy model

It is not exactly known why certain food proteins are more likely to sensitize. One of the characteristics of most food allergens is that they are stable to the acidic and proteolytic conditions in the digestive tract. This property is thought to be a risk factor in allergic sensitization. The purpose of the present study was to investigate the...

The effect of dietary phytosphingosine on cholesterol levels and insulin sensitivity in subjects with the metabolic syndrome

Background: Sphingolipids, like phytosphingosine (PS) are part of cellular membranes of yeasts, vegetables and fruits. Addition of PS to the diet decreases serum cholesterol and free fatty acid (FFA) levels in rodents and improves insulin sensitivity.Objective:To study the effect of dietary supplementation with PS on cholesterol and glucose...

Microbial transglutaminases generate T cell stimulatory epitopes involved in celiac disease

Celiac disease (CD) is a permanent intolerance to gluten. In CD patients, gluten peptides cause an inflammation in the small intestine leading to tissue damage. Tissue transglutaminase (tTG) is an enzyme involved in the repair of damaged tissue by crosslinking of extracellular matrix proteins. Under certain conditions, tTG can deamidate...

Kinetic characteristics of acidic and alkaline ceramidase in human epidermis

It has recently become evident that at least five ceramidase (CDase) isoforms are present in human epidermis, and that specifically acidic CDase (aCDase) and alkaline CDase (alkCDase) activities increase during keratinocyte differentiation, and thus might play a pivotal role(s) in permeability barrier function. Prior to investigating their...

Dietary sphingolipids lower plasma cholesterol and triacylglycerol and prevent liver steatosis

The prevalence of dyslipidemia and obesity resulting from excess energy intake and physical inactivity is increasing. The liver plays a pivotal role in the systemic lipid homeostasis. Effective, natural dietary interventions that lower plasma lipids and promote liver health are needed. APOE*3Leiden mice were fed a Western-type diet, supplemented...

Eetlustremmend en cholesterolverlagend: Functionele ingrediënten tegen overgewicht

Dietary sphingolipids lower plasma cholesterol and triacylglycerol and prevent liver steatosis in APOE*3Leiden mice

Background: The prevalence of dyslipidemia and obesity resulting from excess energy intake and physical inactivity is increasing. The liver plays a pivotal role in systemic lipid homeostasis. Effective, natural dietary interventions that lower plasma lipids and promote liver health are needed. Objective: Our goal was to determine the effect of...

Reversible denaturation of Brazil nut 2S albumin (Ber e1) and implication of structural destabilization on digestion by pepsin

The high resistance of Brazil nut 2S albumin, previously identified as an allergen, against proteolysis by pepsin was examined in this work. Although the denaturation temperature of this protein exceeds the 110 °C at neutral pH, at low pH a fully reversible thermal denaturation was observed at ∼82 °C. The poor digestibility of the protein by...

A novel and sensitive method for the detection of T cell stimulatory epitopes of α/β- and γ-gliadin

Background: It is now generally accepted that coeliac disease (CD) is caused by inflammatory T cell responses to gluten peptides bound to HLA-DQ2 or -DQ8 molecules. There is overwhelming evidence that CD patients can mount T cell responses to peptides found in both α-gliadin and γ-gliadin molecules. Assays that would detect the presence or...

Transglutaminase-Mediated Modification of Glutamine and Lysine Residues in Native Bovine β-Lactoglobulin

Bovine β-lactoglobulin (BLG) is a major component in whey and its physical properties are important for the texture of many dairy-based foods. Modification of proteins with transglutaminase from Streptoverticillium mobaraense (MTGase) can be used to alter their physical properties. MTGase-mediated modification of native BLG was until now,...

Modification of Glutamine and Lysine Residues in Holo and Apo α-Lactalbumin with Microbial Transglutaminase

The molecular structures determine the physical properties of milk proteins and are important for the texture of many dairy-based foods. Bovine α-lactalbumin (α-LA) is a globular 123 amino acid Ca2+ binding milk protein. Modification with microbial Ca2+ independent transglutaminase (MTGase) was used to modify lysines and glutamines in holo and...

Molecular cloning and characterization of the alkaline ceramidase from Pseudomonas aeruginosa PA01

Ceramidase (CDase) hydrolyzes the amide bond in ceramides to yield free fatty acid and sphingosine. From a 3-L Pseudomonas aeruginosa PA01 culture, 70 μg of extracellular alkaline, Ca2+-dependent CDase, was purified to homogeneity, the N-terminal sequence was determined, and the CDase gene was cloned. The CDase gene encodes a 670 amino acid...

Is Candida albicans a trigger in the onset of coeliac disease?

Coeliac disease is a T-cell-mediated autoimmune disease of the small intestine that is induced by ingestion of gluten proteins from wheat, barley, or rye. We postulate that Candida albicans is a trigger in the onset of coeliac disease. The virulence factor of C albicans - hyphal wall protein 1 (HWP1) - contains aminoacid sequences that are...

Synthesis of a novel fluorescent ceramide analogue and its use in the characterization of recombinant ceramidase from Pseudomonas aeruginosa PA01

Ceramidase (CDase) hydrolyses the N-acyl linkage of the sphingolipid ceramide. We synthesized the non-fluorescent ceramide analogue (4E,2S,3R)-2-N-(10-pyrenedecanoyl)-1,3,17-trihydroxy-17- (3,5-dinitrobenzoyl)-4-heptadecene (10) that becomes fluorescent upon hydrolysis of its N-acyl bond. This novel substrate was used to study several kinetic...

Staphylococcus aureus resistance to human defensins and evasion of neutrophil killing via the novel virulence factor MprF is based on modification of membrane lipids with L-lysine

Defensins, antimicrobial peptides of the innate immune system, protect human mucosal epithelia and skin against microbial infections and are produced in large amounts by neutrophils. The bacterial pathogen Staphylococcus aureus is insensitive to defensins by virtue of an unknown resistance mechanism. We describe a novel staphylococcal gene, mprF...