Thrombocytopenia caused by platelet consumption in thrombi is a major manifestation of hemolytic uremic syndrome (HUS) associated with Shiga toxin (Stx) producing Escherichia coli. Platelets have glycosphingolipid receptors capable of binding Stx, but a direct interaction between the toxin and platelets, leading to platelet activation, has not been reported. In this study, it is shown that Stx1 and its B (binding) subunit (Stx1B), at 10 pg/mL to 10 ng/mL, bound to platelets. IntroductionShiga toxin (Stx)-producing Escherichia coli (STEC) have been associated with cases of hemolytic uremic syndrome (HUS). Microangiopathic hemolytic anemia, acute renal failure, and thrombocytopenia characterize this syndrome. Stx has been specifically implicated as a causal factor 1 of HUS because cases of the disease have been associated with Stx-producing strains, 2 the toxin has been identified in the kidney of a patient with HUS, 3 and the toxin has been found to be cytotoxic for renal endothelial and epithelial cells. [4][5][6][7][8] In addition, animal models have reproduced aspects of HUS using wild-type bacteria that produce the toxin 9,10 or purified toxin. 11 The toxin is composed of 5 B, or binding, subunits and 1 enzymatically active A subunit. 12 The molecular weight of the A subunit is 33 000 kd, and that of the pentameric B subunit is approximately 35 000 kd. 13 The B subunit (StxB) binds to a glycosphingolipid receptor on cell membranes, globotriaosyl ceramide (Gb3), containing the terminal disaccharide galactose ␣(1-4) galactose ␤. 14 A recent study showed that Stx could bind to platelets through Gb3 and a novel platelet glycosphingolipid termed band 0.03. 15 Other studies have not been able to reproduce these results. 16,17 Binding to the cell mediates endocytosis of the holotoxin. Intracellularly the A subunit is proteolytically nicked, binds to 60S ribosomes, and thereby inhibits protein synthesis leading to cell death. 18 Thrombocytopenia is an important feature of HUS. Platelets are consumed in small thrombi, and these thrombi may compromise the blood supply to various organs, particularly the kidney. The mechanism by which these thrombi are formed is unclear, and platelet activation has been suggested. Studies performed on platelets from patients with HUS showed impaired aggregating responses 19,20 and reduced ␤-thromboglobulin (␤-TG) content. 19 Platelet-derived products such as ␤-TG, platelet factor 4, 21 and soluble P-selectin 22 were found to be elevated during acute HUS. Furthermore, changes in platelet ultramorphology were noted. 23 Increased platelet-derived microvesicles were found in these patients, 24 indicating platelet activation. Plasma from patients with HUS increased aggregation of normal platelets, but the factor causing this was not determined. 25 Several previous studies have investigated a direct interaction between Stx and platelets. Culture filtrates from Stx-producing E coli were found to induce platelet-aggregating activity, 26 but purified Stx did not increase platelet aggregation 16...

The agricultural sector is thought to be responsible for around 30% of the anthropogenic climate change and it is well established that high meat consumption has a tremendous impact on the environment. Rapeseed is mainly used for production of vegetable oil, but press cake has high protein content with the potential for incorporation into new plant protein-based foods. Protein was recovered from press cakes generated from different oil pressing processes. Industrially cold-pressed, hot-pressed, and solvent-extracted rapeseed press cake and the effect of heat treatment in the recovery process was assessed. Protein recovery yield, protein concentration and emulsifying properties were analyzed. Cold-pressed rapeseed press cake (RPC) recovered in the absence of heat, yielded the highest protein recovery (45%) followed by hot-pressed rapeseed meal (RM) (26%) and solvent-extracted RM (5%). Exposure to heat during recovery significantly reduced the yield for cold-pressed RPC but no difference was found for hot-pressed RM. The protein recovery yield was improved for solvent-extracted RM when heat was applied in the recovery process. The ability to stabilize emulsions was highest for protein recovered from cold-pressed RPC, followed by hot-pressed RM and solvent-extracted RM, and was in the same range as commercial emulsifying agents. Heat treatment during recovery significantly reduced the emulsifying properties for all pressing methods examined. This study suggests that cold-pressed rapeseed press cake without heat in the recovery process could be a successful strategy for an efficient recovery of rapeseed protein with good emulsifying properties.

Milk that does not coagulate after rennet addition, also called noncoagulating (NC) milk, is unwanted in cheese production due to prolonged processing time. Amounts of whey and casein proteins, genetic variants, as well as posttranslational modifications (PTM) of proteins are all contributing factors in rennet-induced coagulation of milk. In this study, we conducted a wideranging investigation of milk proteins in milk samples from 616 Swedish Red dairy cattle using liquid chromatography-high resolution mass spectrometry. Relative concentration of proteins, genetic variants, and PTM were compared between NC milk and coagulating milk. The PTM investigated were phosphorylation of caseins and glycosylation of κ-casein. Several genetic variants and PTM were found, including rare phosphorylation variants of the α S -caseins. Genetic variants were found to effect the expressed amount of different proteins. Further, the effect of protein amounts and PTM on a binary NC milk trait was modeled using a generalized linear model. The model showed that NC milk significantly correlated with higher relative concentrations of α-lactalbumin and β-casein and lower relative concentrations of β-lactoglobulin and κ-casein. Regarding PTM of caseins, an effect on NC milk from a lower relative concentration of α S1 -casein with 8 phosphate groups were found, even though an effect from total relative concentration of α S1 -casein was not found. This study has provided insights into protein variants and PTM important for NC milk to improve this undesirable property.

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