Using 7 cm immobilized pH gradient strips to determine levels of clinically relevant proteins in wheat grain extracts

Improved methods for total and chloroplast protein extraction from Cajanus species for two-dimensional gel electrophoresis and mass spectrometry

The recent advances in pigeon pea genomics, including high-quality whole genome and chloroplast genome sequence information helped develop improved varieties. However, a comprehensive Cajanus proteome, including the organelle proteome, is yet to be fully mapped. The spatial delineation of pigeon pea proteins at sub-cellular levels and inter-organelle communication could offer valuable insights into its defense mechanism against various stresses. However, the major bottleneck in the proteomic study is the lack of a suitable method of protein extraction and sample preparation compatible with two-dimensional gel electrophoresis (2D-PAGE), liquid chromatography-mass spectrometry (LCMS), or matrix-assisted laser desorption ionization-time of flight (MALDi-ToF). Our study introduces two efficient methods, one for isolating total proteins and another for organelle (chloroplast) proteins from various Cajanus spp. For total protein extraction, we have optimized a protocol using phenol in combination with a reducing agent (DTT) and protease inhibitor cocktail, also washing (6-7 times) with ice-cold acetone after overnight protein precipitation of total proteins. Our modified extraction method using phenol for total leaf protein yielded approximately 2-fold more proteins than the previously reported protocols from C. cajan (3.18 ± 0.11 mg/gm) and C. scarabaeoides (2.06 ± 0.08 mg/gm). We have also optimized a protocol for plastid protein extraction, which yielded 1.33 ± 0.25 mg/10 gm plastid proteins from C. cajan and 0.88 ± 0.19 mg/10 gm plastid proteins from C. scarabaeoides. The 2D-PAGE analysis revealed 678 ± 08 reproducible total protein spots from C. cajan and 597 ± 22 protein spots from C. scarabaeoides. Similarly, we found 566 ± 10 and 486 ± 14 reproducible chloroplast protein spots in C. cajan and C. scarabaeoides, respectively. We confirmed the plastid protein fractions through immunoblot analysis using antibodies against LHCb1/LHCⅡ type Ⅰ protein. We found both methods suitable for 2D-PAGE and mass spectrometry (MS). This is the first report on developing protocols for total and chloroplastic protein extraction of Cajanus spp. suitable for advanced proteomics research.

Allergenicity of wheat protein in diet: Mechanisms, modifications and challenges

Wheat is widely available in people's daily diets. However, some people are currently experiencing IgE-mediated allergic reactions to wheat-based foods, which seriously impact their quality of life. Thus, it is imperative to provide comprehensive knowledge and effective methods to reduce the risk of wheat allergy (WA) in food. In the present review, recent advances in WA symptoms, the major allergens, detection methods, opportunities and challenges in establishing animal models of WA are summarized and discussed. Furthermore, an updated overview of the different modification methods that are currently being applied to wheat-based foods is provided. This study concludes that future approaches to food allergen detection will focus on combining multiple tools to rapidly and accurately quantify individual allergens in complex food matrices. Besides, biological modification has many advantages over physical or chemical modification methods in the development of hypoallergenic wheat products, such as enzymatic hydrolysis and fermentation. It is worth noting that using biotechnology to edit wheat allergen genes to produce allergen-free food may be a promising method in the future which could improve the safety of wheat foods and the health of allergy sufferers.

Are current analytical methods suitable to verify VITAL® 2.0/3.0 allergen reference doses for EU allergens in foods?

Food allergy affects up to 6% of Europeans. Allergen identification is important for the risk assessment and management of the inadvertent presence of allergens in foods. The VITAL® initiative for voluntary incidental trace allergen labeling suggests protein reference doses, based on clinical reactivity in food challenge studies, at or below which voluntary labelling is unnecessary. Here, we investigated if current analytical methodology could verify the published VITAL® 2.0 doses, that were available during this analysis, in serving sizes between 5 and 500 g. Available data on published and commercial ELISA, PCR and mass spectrometry methods, especially for the detection of peanuts, soy, hazelnut, wheat, cow's milk and hen's egg were reviewed in detail. Limit of detection, quantitative capability, matrix compatibility, and specificity were assessed. Implications by the recently published VITAL® 3.0 doses were also considered. We conclude that available analytical methods are capable of reasonably robust detection of peanut, soy, hazelnut and wheat allergens for levels at or below the VITAL® 2.0 and also 3.0 doses, with some methods even capable of achieving this in a large 500 g serving size. Cow's milk and hen's egg are more problematic, largely due to matrix/processing incompatibility. An unmet need remains for harmonized reporting units, available reference materials, and method ring-trials to enable validation and the provision of comparable measurement results.

Soybean recovery from stress imposed by multigenerational growth in contaminated Chernobyl environment

Ionizing radiation is a genotoxic anthropogenic stressor. It can cause heritable changes in the plant genome, which can be either adaptive or detrimental. There is still considerable uncertainty about the effects of chronic low-intensity doses since earlier studies reported somewhat contradictory conclusions. Our project focused on the recovery from the multiyear chronic ionizing radiation stress. Soybean (Glycine max) was grown in field plots located at the Chernobyl exclusion zone and transferred to the clean ground in the subsequent generation. We profiled proteome of mature seeds by two-dimensional gel electrophoresis. Overall, 15 differentially abundant protein spots were identified in the field comparison and 11 in the recovery generation, primarily belonging to storage proteins, disease/defense, and metabolism categories. Data suggested that during multigenerational growth in a contaminated environment, detrimental heritable changes were accumulated. Chlorophyll fluorescence parameters were measured on the late vegetative state, pointing to partial recovery of photosynthesis from stress imposed by contaminating radionuclides. A plausible explanation for the observed phenomena is insufficient provisioning of seeds by lower quality resources, causing a persistent effect in the offspring generation. Additionally, we hypothesized that immunity against phytopathogens was compromised in the contaminated field, but perhaps even primed in the clean ground, yet this idea requires direct functional validation in future experiments. Despite showing clear signs of physiological recovery, one season was not enough to normalize biochemical processes. Overall, our data contribute to the more informed agricultural radioprotection.

An Effective Method of Isolating Honey Proteins

Honey is a natural sweetener composed mostly of sugars, but it contains also pollen grains, proteins, free amino acids, and minerals. The amounts and proportions of these components depend on the honey type and bee species. Despite the low content of honey protein, they are becoming a popular study object, and have recently been used as markers of the authenticity and quality of honey. Currently, the most popular methods of protein isolation from honey are dialysis against distilled water, lyophilization of dialysate, or various precipitation protocols. In this work, we propose a new method based on saturated phenol. We tested it on three popular polish honey types and we proved its compatibility with both 1D and 2D polyacrylamide gel electrophoresis (PAGE) and MS (mass spectrometry) techniques. The elaborated technique is also potentially less expensive and less time-consuming than other previously described methods, while being equally effective.