Can proteomics contribute to biomonitoring of aquatic pollution? A critical review.

Aquatic pollution is one of the greatest environmental problems, and therefore its control represents one of the major challenges in this century. In recent years, proteomics has emerged as a powerful tool for searching protein biomarkers in the field of pollution biomonitoring. For biomonitoring marine contamination, there is a consensus that bivalves are preferred organisms to assess organic and inorganic pollutants. Thus, the bivalve proteome was intensively studied, particularly the mussel. It is well documented that heavy metal pollution and organic chemicals altered the structural proteins causing degradation of tissues of molluscs. Also, it is well known that proteins involved in stress oxidative such as glutathione and enzymes as catalase, superoxide dismutase or peroxisomes are overexpressed in response to contaminants. Additionally, using bivalves, other groups of proteins proposed as pollution biomarkers are the metabolic proteins. Even though other marine species are used to monitor the pollution, the presence of proteomic tools in these studies is scarce. Concerning freshwater pollution field, a great variety of animal species (fish and crustaceans) are used as biomonitors in proteomics studies compared to plants that are scarcely analysed. In fish species, proteins involved in stress oxidative such as heat shock family or proteins from lipid and carbohydrate metabolism were proposed as candidate biomarkers. On the contrary, for crustaceans there is a lack of proteomic studies individually assessing the contaminants. Novel scenarios, including emerging contaminants and new threats, will require proteomic technology for a systematic search of protein biomarkers and a greater knowledge at molecular level of those cellular pathways induced by contamination.

Measuring quantitative proteomic distance between Spanish beef breeds.

Estimates of quantitative proteomic distance between populations have not been reported to date. Here, quantitative proteomic distances between three Spanish bovine breeds (Asturiana de los Valles, AV; Retinta, RE; and Rubia Gallega, RG) were estimated from two-dimensional electrophoresis profiles of meat samples of longissimus thoracis muscle at 2 h post-mortem. Statistically significant distances were detected between AV/RG and the most genetically different RE breed, using the novel QD measure of quantitative proteomic distance. In total, 18 differentially abundant myofibrillar and sarcoplasmic proteins/isoforms contributing to proteomic distances between breeds were confidently identified by tandem mass spectrometry. The fast skeletal myosin regulatory light chain 2 followed by other five interacting proteins exhibited the most pronounced relative change between breeds. In addition, most differentially represented proteins could be associated with variations in meat tenderness. Therefore, they could be candidate biomarkers for molecular breeding programs and authentication of the three Spanish beef breeds.

Molecular insight into taste and aroma of sliced dry-cured ham induced by protein degradation undergone high-pressure conditions.

High pressure processing (HPP) is currently being developed to increase the shelf-life of sliced dry-cured ham in convenience package without detrimental effects on texture and sensorial characteristics. This study is focused on protein degradation under pressure conditions and its contribution to taste and aroma. Samples of sliced dry-cured ham undergone HPP (600 Pa, 0-35 °C) were analyzed from different approaches including proteomic and chemical analysis (amino acids and volatile compounds). Proteomic analysis revealed that high-pressure conditions caused a higher level of proteolysis, displaying that actin (ACTC1) was differentially degraded, unlike myosin. Furthermore, main Strecker metabolites-isoleucine and leucine-were more abundant at lower temperatures as opposed to 2-methyl butanal and 3-methyl butanal under HPP. Moreover, this study confirmed that HPP affected positively linear aldehydes (pentanal, hexanal, heptanal and nonanal) because of produce a decrease of them, which could improve flavor and taste of dry-cured ham.

Proteomic footprint of ultrasound intensification on sliced dry-cured ham subjected to mild thermal conditions.

Ultrasound can intensify the heating process used to correct texture defects in dry-cured hams. The effect of ultrasound-assisted heating on the proteome of sliced dry-cured ham was evaluated. Dry-cured hams with high proteolysis index (PI > 36) were sliced, vacuum packed and subjected to conventional (CV) and ultrasound-assisted (US) thermal treatments. Comparative proteome profiling between sample groups was assessed by two-dimensional electrophoresis (2-DE) coupled to tandem mass spectrometry. It was found that protein fragmentation increased markedly after US thermal treatment. Specifically, fragments of the major myofibrillar protein, actin, were abundantly over-represented following US heating. In addition, five unfragmented sarcoplasmic proteins (i.e. fatty acid-binding protein, peroxiredoxin-6, superoxide dismutase, carbonyl reductase and aminoacylase) showed increased abundance in the US sample group. These results suggest candidate biomarkers to monitor proteolysis intensity and proteolysis-independent effects linked to cured ham quality by ultrasound application. SIGNIFICANCE: The present proteome profiling study of treated dry-cured ham demonstrates the impact of ultrasound action on proteins. Moreover, negative organoleptic effects can be appearing with ultrasound treatment due to proteolysis increase. Therefore, the proteolysis monitoring could help to control these effects. In this regards, our results suggest that actin can be a candidate biomarker to monitor proteolysis intensity.

Comparative proteomic profiling of myofibrillar proteins in dry-cured ham with different proteolysis indices and adhesiveness.

Excessive proteolysis during dry-cured ham processing may lead to high adhesiveness and consumer dissatisfaction. The aim of this research is to identify biomarkers for proteolysis and adhesiveness. Two hundred biceps femoris porcine muscle samples from Spanish dry-cured ham were firstly evaluated for various physicochemical parameters, including their proteolysis indices and instrumental adhesiveness. Proteins of samples with extreme proteolysis indices were separated by two-dimensional electrophoresis and identified by tandem mass spectrometry (MALDI-TOF/TOF). We found that hams of higher proteolysis index had statistically significant increased adhesiveness. Proteomic analysis revealed statistically significant qualitative and quantitative differences between sample groups. Thus, protein fragments increased remarkably in samples with higher proteolysis index scores. In addition, higher proteolysis index hams showed increased degradation for a total of five non-redundant myofibrillar and sarcoplasmic proteins. However, myosin-1, α-actin and myosin-4 proteins were the biomarkers that underwent the most intense response to proteolysis and adhesiveness.