Myosin isoforms in red and white muscles of some marine teleost fishes

Genome-Wide Identification, Characterization and Expression Profiling of myosin Family Genes in Sebastes schlegelii

Myosins are important eukaryotic motor proteins that bind actin and utilize the energy of ATP hydrolysis to perform a broad range of functions such as muscle contraction, cell migration, cytokinesis, and intracellular trafficking. However, the characterization and function of myosin is poorly studied in teleost fish. In this study, we identified 60 myosin family genes in a marine teleost, black rockfish (Sebastes schlegelii), and further characterized their expression patterns. myosin showed divergent expression patterns in adult tissues, indicating they are involved in different types and compositions of muscle fibers. Among 12 subfamilies, S. schlegelii myo2 subfamily was significantly expanded, which was driven by tandem duplication events. The up-regulation of five representative genes of myo2 in the skeletal muscle during fast-growth stages of juvenile and adult S. schlegelii revealed their active role in skeletal muscle fiber synthesis. Moreover, the expression regulation of myosin during the process of myoblast differentiation in vitro suggested that they contribute to skeletal muscle growth by involvement of both myoblast proliferation and differentiation. Taken together, our work characterized myosin genes systemically and demonstrated their diverse functions in a marine teleost species. This lays foundation for the further studies of muscle growth regulation and molecular mechanisms of indeterminate skeletal muscle growth of large teleost fishes.

Protein Signatures to Trace Seafood Contamination and Processing

This review presents some applications of proteomics and selected spectroscopic methods to validate certain aspects of seafood traceability. After a general introduction to traceability and the initial applications of proteomics to authenticate traceability information, it addresses the application of proteomics to trace seafood exposure to some increasingly abundant emergent health hazards with the potential to indicate the geographic/environmental origin, such as microplastics, triclosan and human medicinal and recreational drugs. Thereafter, it shows the application of vibrational spectroscopy (Fourier-Transform Infrared Spectroscopy (FTIR) and Fourier-Transform Raman Spectroscopy (FT Raman)) and Low Field Nuclear Magnetic Resonance (LF-NMR) relaxometry to discriminate frozen fish from thawed fish and to estimate the time and temperature history of frozen fillets by monitoring protein modifications induced by processing and storage. The review concludes indicating near future trends in the application of these techniques to ensure seafood safety and traceability.

Peptide mapping of polymorphic myosin heavy chain isoforms in different muscle types of some freshwater teleosts

A modified SDS-PAGE system has been employed to resolve polymorphic myosin heavy chain (MyHC) isoforms in different muscle types of three freshwater teleosts displaying different modes of respiration, adaptive features and life styles. Investigated species include accessory air-breather Channa punctata along with exclusive aquatic breather major carps Labeo rohita and Catla catla. All the selected species show specificity and expressivity of at least three MyHC isoforms, one each in red, head and pectoral muscles. Chymotryptic peptide maps unambiguously support substructural individuality of each MyHC isoforms with the type-specific dispersal of chymotryptic cleavage sites. Specific Ca(2+)- and Mg(2+)-ATPase activities of natural actomyosin (NAM) of lateral line red muscle of C. punctata were low and less sensitive to pH, but sensitive to KCl concentrations between 0.05 and 0.15 M. In comparison, the specific enzymatic activities of NAM of red muscle from the carps (L. rohita and C. catla) were substantially high with prominent peaks at pH 7.5 and near insensitivity to 0.05-0.15 M KCl, while C. punctata had shown a different response at these molarities. Thus, the data favor a correlation between breathing modes and life style and the differences in pH or ionic strength sensitivities of ATPases. Unique profiles of peptide maps and the dispersal patterns of hydrophobic residues (cleavage sites of chymotrypsin) in MyHC of different muscle types further reflect individuality of their evolutionary histories.

White muscle differentiation in the eel (Anguilla anguilla L.): changes in the myosin isoforms pattern and ATPase profile during post-metamorphic development

Myosin isoforms and their light and heavy chains subunits were studied in the white lateral muscle of the eel during the post metamorphic development, in relation with the myosin ATPase profile. At elver stage VI A1 the myosin isoforms pattern was characterized by at least two isoforms, FM3 and FM2. The fast isomyosin type 1 (FM1) appeared during subsequent development. It increased progressively in correlation with the increase in the level of the light chain LC3f. FM1 became predominant at stage VI A4. At the elver stage VI A1, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed at least two heavy chains, namely type II-1 and II-2. The type II-1 heavy chain disappeared in the yellow eel white muscle, and V8-protease peptide map showed the appearance of a minor heavy chain type II-3 as early as stage VI B. Comparison of myosin heavy chains and myosin isoforms patterns showed the comigration of different myosin isoforms during white muscle development. The myosin ATPase profile was characterized by a uniform pattern as far as stage VI A4. A mosaic aspect in white muscle was observed as early as stage VI B, showing the appearance of small acid labile fibers. This observation suggests that the type II-3 heavy chain is specific to the small fibers.