Physicochemical and Microstructural Characterization of Whey Protein Films Formed with Oxidized Ferulic/Tannic Acids

Protein-based biodegradable packaging films are of environmental significance. The effect of oxidized ferulic acid (OFA)/tannic acid (OTA) on the crosslinking and film-forming properties of whey protein isolate (WPI) was investigated. Both of the oxidized acids induced protein oxidation and promoted WPI crosslinking through the actions of quinone carbonyl and protein sulfhydryl, and amino groups. OTA enhanced the tensile strength (from 4.5 MPa to max 6.7 MPa) and stiffness (from 215 MPa to max 376 MPa) of the WPI film, whereas OFA significantly increased the elongation at break. The water absorption capability and heat resistance of the films were greatly improved by the addition of OTA. Due to the original color of OTA, the incorporation of OTA significantly reduced light transmittance of the WPI film (λ 200–600 nm) as well as the transparency, whereas no significant changes were induced by the OFA treatment. Higher concentrations of OTA reduced the in vitro digestibility of the WPI film, while the addition of OFA had no significant effect. Overall, these two oxidized polyphenols promoted the crosslinking of WPI and modified the film properties, with OTA showing an overall stronger efficacy than OFA due to more functional groups available.

Context-dependent monoclonal antibodies against protein carbamidomethyl-cysteine

Protein sulfhydryl residues participate in key structural and biochemical functions. Alterations in sulfhydryl status, regulated by either reversible redox reactions or by permanent covalent capping, may be challenging to identify. To advance the detection of protein sulfhydryl groups, we describe the production of new Rabbit monoclonal antibodies that react with carbamidomethyl-cysteine (CAM-cys), a product of iodoacetamide (IAM) labeling of protein sulfhydryl residues. These antibodies bind to proteins labeled with IAM (but not N-ethylmaleimide (NEM) or acrylamide) and identify multiple protein bands when applied to Western blots of cell lysates treated with IAM. The monoclonal antibodies label a subset of CAM-cys modified peptide sequences and purified proteins (human von Willebrand Factor (gene:vWF), Jagged 1 (gene:JAG1), Laminin subunit alpha 2 (gene:LAMA2), Thrombospondin-2 (gene:TSP2), and Collagen IV (gene:COL4)) but do not recognize specific proteins such as Bovine serum albumin (gene:BSA) and human Thrombospondin-1 (gene:TSP1), Biglycan (gene:BGN) and Decorin (gene:DCN). Scanning mutants of the peptide sequence used to generate the CAM-cys antibodies elucidated residues required for context dependent reactivity. In addition to recognition of in vitro labeled proteins, the antibodies were used to identify selected sulfhydryl-containing proteins from living cells that were pulse labeled with IAM. Further development of novel CAM-cys monoclonal antibodies in conjunction with other biochemical tools may complement current methods for sulfhydryl detection within specific proteins. Moreover, CAM-cys reactive reagents may be useful when there is a need to label subpopulations of proteins.

Effects of single and binary applications of bisphenol A and NaCl on Ceratopyllum demersum

Determining the physiological effects of single and binary applications of BPA and NaCl on the Ceratophyllum demersum L., which is a rootless submerged aquatic macrophyte, is the aim of the present study. For this purpose, the macrophyte was collected from a local pond that was not exposed to any pollution. Macrophytes were acclimatized in 10% nutrient solution for 14 days, than they were treated with 17.2 mg/L BPA; 10 and 100 mM NaCl; 17.2 mg/L BPA plus 10 mM NaCl and 17.2 mg/L BPA plus 100 mM NaCl. The macrophyte without added BPA or/and NaCl served as control (without treatment). Increasing concentrations of NaCl induced a progressive accumulation of Na in the macrophyte tissues. On the other hand, BPA application partially reduced Na uptake. Nutrient uptake was affected differently by the applications. The contents of some nutrients such as Cu, Zn, Mn, K and Mg were generally reduced, whereas the Fe and Ca contents were increased. In general, increases in contents of total carbohydrate, total phenolic and non-protein sulfhydryl groups were found, when compared to control. Protein and photosynthetic pigment contents, on the contrary to these, were decreased. According to findings, the increase in H2O2 and MDA levels showed that single and combined applications of BPA and NaCl in C. demersum tissues induced oxidative stress.

Oxidative Modifications in Advanced Atherosclerotic Plaques: A Focus on In Situ Protein Sulfhydryl Group Oxidation

Although oxidative stress has been long associated with the genesis and progression of the atherosclerotic plaque, scanty data on its in situ effects on protein sulfhydryl group modifications are available. Within the arterial wall, protein sulfhydryls and low-molecular-weight (LMW) thiols are involved in the cell regulation of both Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) levels and are a target for several posttranslational oxidative modifications that take place inside the atherosclerotic plaque, probably contributing to both atherogenesis and atherosclerotic plaque progression towards complicated lesions. Advanced carotid plaques are characterized by very high intraplaque GSH levels, due to cell lysis during apoptotic and/or necrotic events, probably responsible for the altered equilibrium among protein sulfhydryls and LMW thiols. Some lines of evidence show that the prooxidant environment present in atherosclerotic tissue could modify filtered proteins also by protein-SH group oxidation, and demonstrate that particularly albumin, once filtered, represents a harmful source of homocysteine and cysteinylglycine inside the plaque. The oxidative modification of protein sulfhydryls, with particular emphasis to protein thiolation by LMW thiols and its association with atherosclerosis, is the main topic of this review.

Precompetitional Weight Reduction Modifies Prooxidative-Antioxidative Status in Judokas

Objective. The main aim of the study was an assessment of the influence of rapid weight loss on oxidative stress parameters in judokas differing in weight reduction value. Materials and Methods. The study included 30 judokas with an age range of 18-30 years (mean age: 22.4±3.40 years). Enzymatic and nonenzymatic antioxidative markers, lipid peroxidation markers, and total oxidative stress were assessed three times: one week before a competition (the first stage), after gaining the desired weight (the second stage), and one week after the competition (the third stage). Results. Between the first and the second stage, the concentration of lipid hydroperoxides (LPH) decreased significantly. The superoxide dismutase (SOD), copper- and zinc-containing superoxide dismutase (Cu,Zn-SOD), ceruloplasmin (CER), malondialdehyde (MDA), LPH, and total oxidative stress (TOS) concentrations were the lowest one week after the competition. Linear regression indicated that the emphases on increased weight reduction increased the activity of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and protein sulfhydryl (PSH) between the first and the second stage of the study. Moderate weight reduction (2-5%) resulted in elevated levels of SOD, Mn-SOD, LPH, MDA, and TOS in comparison to low and high reductions. An opposite relation was observed in PSH. In judokas, the precompetitional weight reduction range was 0.44-6.10% (mean: 2.93%±1.76%) of the initial body weight. Concentrations of superoxide dismutase (SOD; p<.01), manganese-dependent superoxide dismutase (Mn-SOD; p<.001), and ceruloplasmin (CER; p<.05) decreased between the first and the third stage of the study as well between the second and third one. Before competitions, a decrease in lipid hydroperoxide (LPH; p<.01) concentration was observed. A reduction of malondialdehyde (MDA; p<.05), LPH (p<.01), and total oxidative stress (TOS; p<.05) levels between the first and the final stage occurred. The increase in weight reduction was linearly correlated with the rise of glutathione peroxidase (GPx; p<.05), glutathione reductase (GR; p<.05), glutathione S-transferase (GST; p<.05), and protein sulfhydryl (PSH; p<.05) concentrations between the first and the second stage of the study. Moderate weight reduction (2-5%) resulted in elevated levels of SOD (p<.05), Mn-SOD (p<.05), LPH (p<.05), MDA (p<.05), and TOS (p<.05) in comparison to low and high reductions. An opposite relation was observed in PSH (p<.005). Conclusions. The effect of weight reduction in judo athletes on prooxidative-antioxidative system diversity depends on the weight reduction value.

Depletion of protein thiols and the accumulation of oxidized thioredoxin in Parkinsonism disclosed by a red-emitting and environment-sensitive probe

Protein sulfhydryl groups play a vital role in maintaining cellular redox homeostasis and protein functions and have attracted increasing interests for the selective detection of protein thiols over low-molecular-weight thiols (LMWTs).

Allantoin improves histopathological evaluations in a rat model of gastritis

Purpose Gastritis is found to be one of the most common gastrointestinal diseases worldwide. However, current therapeutic agents cause side effects, interaction, and recurrence. Allantoin has anti-inflammatory and wound healing properties. In this study, the therapeutic effect of allantoin has been assessed on the histopathological indices and gastric mucosal barrier of male rats. Methods Male rats were equally divided into control, ethanol-induced gastritis, and allantoin groups. The therapeutic groups consisted of gastritis plus 12.5 mg/kg allantoin, gastritis plus 25 mg/kg allantoin, and gastritis plus 50 mg/kg allantoin groups. After 5 days of allantoin administration, the rats were sacrificed and a part of their gastric tissue was maintained at −70 °C for prostaglandin E2 (PGE2) and non-protein sulfhydryl (NP-SH) measurements. Another part was stained with hematoxylin and eosin and Masson’s trichrome. Results We found that Allantoin increased parietal and mucosal cell counts and mucosal thickness after gastritis induction. In addition, the number of leukocytes and vessels decreased in both of the mucosal and the submucosal layers. Allatoin improved gastric ulcer in all treatment groups. Gastric levels of PGE2 and NP-SH increased after allantoin treatment. Conclusion This study indicated that allantoin had a considerable effect on gastritis treatment, which seems to result from the reinforcement of gastric mucosal barrier.

A conserved MFS orchestrates a subset of O-glycosylation to facilitate macrophage dissemination and tissue invasion

SUMMARYAberrant display of the truncated core1 O-glycan T-antigen is a common feature of human cancer cells that correlates with metastasis. Here we show that T-antigen in Drosophila melanogaster macrophages is involved in their developmentally programmed tissue invasion. Higher macrophage T-antigen levels require an atypical major facilitator superfamily (MFS) member that we named Minerva which enables macrophage dissemination and invasion. We characterize for the first time the T and Tn glycoform O-glycoproteome of the Drosophila melanogaster embryo, and determine that Minerva increases the presence of T-antigen on protein pathways previously linked to cancer, most strongly on the protein sulfhydryl oxidase Qsox1 which we show is required for macrophage invasion. Minerva’s vertebrate ortholog, MFSD1, rescues the minerva mutant’s migration and T-antigen glycosylation defects. We thus identify a key conserved regulator that orchestrates O-glycosylation on a protein subset to activate a program governing migration steps important for both development and cancer metastasis.