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Background and Objectives: Zein proteins of maize endosperm are nutritionally poor, but important for vitreous kernel texture. The Opaque‐2 mutation enhances the protein quality but downregulates zein expression, distorting the kernel texture. Quality protein maize (QPM) is nutritionally improved, hard endosperm maize developed by introgression of endosperm modifiers under an opaque‐2 background. The present study aims to analyze the variability in zein expression patterns in normal, opaque‐2, and QPM lines through sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and two‐dimensional gel electrophoresis analyses. Findings: Results revealed that the total number of zein isoforms is almost similar in opaque‐2, normal, and QPM lines. Overall, in this study, it is concluded that the opaque‐2 mutation specifically affects the expression of high‐molecular‐weight zeins, which are being counterbalanced by the expression of low‐molecular‐weight zein isoforms and nonzein proteins. Conclusion: Genomic data retrieval studies revealed the possible presence of multiple 27 kDa isoforms with varied isoelectric points (pI), which is a subject for further investigation. The differential expression of 15 kDa zein in QPM emerged as a novel player in endosperm modification. Significance and Novelty: The present study provides insight into the diversified expression of zeins in different maize types. The variable isoform expression has the potential to generate stable QPM lines by targeting effective isoforms, ensuring endosperm modification without hampering the nutritional quality. [ABSTRACT FROM AUTHOR]

Protocols that improve growth performance in fish while assuring product quality are important for aquaculture. Fasting followed by refeeding may promote compensatory growth, thus optimizing growth performance. During fasting and refeeding, fast-twitch muscle, which comprises most of fish fillet, undergoes intense plasticity. In this work, we studied the proteome of pacu (Piaractus mesopotamicus) fast-twitch muscle after 30 days of fasting (D30), 30 days of refeeding (D60) and 60 days of refeeding (D90) with two-dimensional electrophoresis, mass spectrometry and bioinformatics. Body mass, growth rate and muscle histology were also assessed. At D30, fish presented muscle catabolism and decreased growth. Proteomic analysis showed that metabolism proteins were the most affected, up and downregulated. Cytoskeleton and amino acid biosynthesis proteins were downregulated, while nuclear and regulatory proteins were upregulated. At D60, fish showed accelerated growth, despite the body mass not completely recovering. Metabolism proteins were still the most affected. Amino acid biosynthesis proteins became upregulated, while cytoskeleton proteins remained downregulated. At D90, the fish presented total compensatory growth. Many metabolic proteins were up or downregulated. Few cytoskeleton proteins remained differentially expressed. Amino acid biosynthesis proteins were mostly upregulated, but less than at D60. Prolonged fasting followed by refeeding also led to the regulation of possible meat quality biomarkers, such as antioxidant enzymes. This fact suggests possible consequences of this protocol on fish meat quality. Our work also enriches our knowledge on proteomic changes during muscle plasticity that occur during fasting and refeeding diet protocols. Unlabelled Image • 30 days of fasting and 60 days of refeeding led to total compensatory growth in pacu. • The first proteomic analysis of skeletal muscle in fasted-refed fish was performed. • Prolonged fasting and refeeding may affect pacu meat quality. [ABSTRACT FROM AUTHOR]

The article focuses on a study for improved detection and separation of rice prolamin polypeptides extraction by two dimensional polyacrylamide gel electrophoresis and amino acid sequencing. It also analyzes the details of changes in composition in the seed storage protein in LGC1 rice mutant which shows low glutelin and high prolamin content. It describes importance of proteomic analysis in identification of composition changes of storage proteins in rice grown by different cultivators.

Placenta is a tissue unique to pregnancy and despite its major role in pregnancy, little is known about the proteome changes within placenta during pregnancy-related diseases such as pre-eclampsia (PE). Therefore, the aim of this study is the analysis of proteome differences between pre-eclamptic and normal full-term placentas. To achieve this goal, five normal and five severe pre-eclamptic placentas were included in this study. Total placental proteins were extracted and subjected to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). After staining, the gels were scanned and the protein spots were analysed using Image Master 2D Platinum Software. Non-parametric Mann–Whitney test was used for analysis of the mean intensity differences of the spots between normal and pre-eclamptic placentas. Statistical analysis indicated that 17 spots were differently expressed in pre-eclamptic compared with normal placentas (p <0.05). Using Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI TOF/TOF) mass analysis, 11 out of 17 spots were identified. Among them, four proteins (chloride intracellular channel 3, apolipoprotein A-I, transthyretin (TTR) and protein disulphide isomerase) were up-regulated while seven (peroxiredoxin 2, peroxiredoxin 3, Hsc 70, Cu/Zn-superoxide dismutase (SOD-1), actin gamma 1 propeptide, chain A of enoyl-coenzyme A hydratase and HSP gp96) showed decreased expression in PE in comparison with normal placentas. In conclusion, down-regulation of proteins with anti-oxidant activities (peroxiredoxin 2 and peroxiredoxin 3) and altered expression of stress-response proteins (Hsc 70, Hsp gp96 and protein disulphide isomerase) might play an important role in the pathogenesis of PE. [Copyright &y& Elsevier]

The intention of this review is to provide an overview of current methodologies employed in the rapidly developing field of ocular proteomics with emphasis on sample preparation, two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry (MS). Appropriate sample preparation for the diverse range of cells and tissues of the eye is essential to ensure reliable results. Current methods of protein staining for 2D-PAGE, protein labelling for two-dimensional difference gel electrophoresis, gel-based expression analysis and protein identification by MS are summarised. The uses of gel-free MS-based strategies (MuDPIT, iTRAQ, ICAT and SILAC) are also discussed. Proteomic technologies promise to shed new light onto ocular disease processes that could lead to the discovery of strong novel biomarkers and therapeutic targets useful in many ophthalmic conditions. [ABSTRACT FROM AUTHOR]

Summary: To contribute to Mycobacterium bovis BCG characterization, two substrains were analyzed using two-dimensional gel electrophoresis (2D-PAGE) and mass spectrometry (MS), based on their protective efficacy in a pulmonary-tuberculosis mouse model. Cell-fraction proteins of BCG Denmark and Phipps substrains were separated into ∼500 spots in 2D-PAGE. The proteomes were similar in protein number, and isoelectric point (pI) and molecular mass (MM) distribution. Statistical analysis, resulted in 72 spots with no change, and 168 and 90 unique for BCG Phipps or Denmark, respectively. Two hundred and fourteen spots showed changes in intensity of >1-fold, 138 of Denmark, and 76 of Phipps. Seventeen spots were selected for MS-based identification (13 from Phipps and 4 from Denmark), including unique, as well as proteins with changes in intensity. The proteins identified participate in virulence, detoxification, adaptation, lipid metabolism, information pathways, cell wall and cell processes, intermediary metabolism and respiration, or still hypotheticals. Our findings contribute to phenotype characterization of BCG substrains and provide new elements to consider for the design of diagnostic tools, drug targets and a new vaccine against tuberculosis based upon protein expression through quantitative statistical analysis. [Copyright &y& Elsevier]

Abstract: Parasites of the genus Leishmania are the causative agents of a range of clinical manifestations collectively known as Leishmaniasis, a disease that affects 12 million people worldwide. With the aim of identifying potential secreted protein targets for further characterization, we have applied two-dimensional gel electrophoresis and mass spectrometry methods to study the soluble protein content of the microsomal fraction from two Leishmania species, Leishmania L. major and L. L. amazonensis. MALDI-TOF peptide mass fingerprint analysis of 33 protein spots from L. L. amazonensis and 41 protein spots from L. L. major identified 14 proteins from each sample could be unambiguously assigned. These proteins include the nucleotide diphosphate kinase (NDKb), a calpain-like protease, a tryparedoxin peroxidase (TXNPx) and a small GTP-binding Rab1-protein, all of which have a potential functional involvement with secretion pathways and/or environmental responses of the parasite. These results complement ongoing genomic studies in Leishmania, and are relevant to further understanding of host/parasite interactions. [Copyright &y& Elsevier]