The occurrence of two types of fast skeletal myosin heavy chains from abdominal muscle of kuruma shrimp Marsupenaeus japonicus and their different tissue distribution

Red color-related proteins from the shell of red swamp crayfish (Procambarus clarkii): Isolation, identification and bioinformatic analysis

Two water-soluble red color-related proteins with the molecular masses of 24 and 73 kDa were purified from the shell of Procambarus clarkii. Initial color changes of these two proteins were detected at 30 °C and the large amount of red precipitate were obtained at 80 °C. PAGE analysis showed that the 24 kDa protein was the monomer, while the 73 kDa protein was the trimer. Identification revealed that these two proteins belonged to the hemocyanin subunit 2 family. With respect to the amino acid sequence similarity, the red color-related proteins shared the highest sequence identity with the hemocyanin derived from giant freshwater prawn (Macrobrachium rosenbergii). The phylogenetic tree analysis also clearly supported this finding. The shell-derived red color-related proteins show potential use as the edible thermal-sensitive indicator in food processing field.

Myology of juvenile freshwater prawn Macrobrachium amazonicum (Decapoda, Caridea): Morphology and swimming implication

Little is known about the functional morphology of locomotion in prawns, and even fewer studies have succeeded in relating a specific muscular group to the movement of the body. The present study aimed to describe the morphology of the thoracoabdominal muscle system and its implications for swimming in juveniles of Macrobrachium amazonicum. Ten muscles were observed in the abdominal muscular system in juveniles of M. amazonicum. The complex arrangement of the anterior oblique muscle in association with the central muscles occupies most of the abdominal space. This muscular compound could promote a flexion movement of the abdomen for body propulsion as well as the tail movement during swimming. Morphofunctional continuity between thoracic and abdominal muscles could aid in locomotion and support the abdominal movement. Moreover, collagen plays a valuable role in connecting deep muscles not inserted in the carapace. Collagenous fascia could transmit the tension during the contraction of deep muscles for coordinated movement.

Purification, characterization and antibacterial activities of red color-related protein found in the shell of kuruma shrimp, Marsupenaeus japonicus

The well-known red color change plays a significant role in consumer acceptability of crustacean species. In this study, we described the purification of the red color-related protein named MjRCP75 from the shell of Marsupenaeus japonicus. It was a homogeneous monomer with molecular mass of 75 kDa and rich in α-helix conformation. The α-helix content decreased within the increasing of heating temperature and was transformed dominantly to β types. Identification and structural analysis revealed that MjRCP75 belonged to hemocyanin family. The released pigment from heated MjRCP75 showed a λmax at 483 nm in acetone. MjRCP75 showed clearly antibacterial activity against Escherichia coli, Staphylococcus aureus, and Vibrio parahaemolyticus. These findings identify MjRCP75 as the red color-related protein in M. japonicus shell and reveal its involvement in antibacterial activities.

Changes in free amino acid concentrations and associated gene expression profiles in the abdominal muscle of kuruma shrimp Marsupenaeus japonicus acclimated at different salinities

Shrimps inhabiting the coastal water can survive in a wide range of salinity. However, the molecular mechanisms involved in their acclimation to different environmental salinities have remained largely unknown. In the present study, we acclimated kuruma shrimp Marsupenaeus japonicus at 1.7 %, 3.4 % and 4.0 % salinities. After acclimating for 6, 12, 24 and 72 h, we determined free amino acid concentrations in their abdominal muscle, and performed RNA-seq analysis on this muscle. The concentrations of free amino acids were clearly altered depending on salinity after acclimating for 24 h. Glutamine and alanine concentrations were markedly increased following the increase of salinity. In association with such changes, many genes related to amino acid metabolism changed their expression levels. In particular, the increase of the expression level of the gene encoding glutamate-ammonia ligase which functions in the glutamine metabolism appeared to be relevant to the increased glutamine concentration at high salinity. Furthermore, the alanine concentration increased at high salinity was likely to be associated with the decrease in the expression levels of the alanine-glyoxylate transaminase gene. Thus, there is a possibility that changes in the concentration of free amino acids for osmoregulation in kuruma shrimp are regulated by changes in the expression levels of genes related to amino acid metabolism.

Insights into Cryoprotective Roles of Carrageenan Oligosaccharides in Peeled Whiteleg Shrimp (Litopenaeus vannamei) during Frozen Storage

The cryoprotective effects of carrageenan oligosaccharides on peeled whiteleg shrimp were investigated and compared with sodium pyrophosphate treatment during frozen storage, primarily the interaction mechanisms between oligosaccharides and shrimp myosin. Data revealed significant profitable effects on water-holding capacity and textural variables in oligosaccharide-treated shrimp compared to the control. Chemical analyses showed that these saccharides maintained a higher myofibrillar protein content and Ca²⁺-ATPase activity in frozen shrimp. Additionally, the hematoxylin and eosin staining results indicated that the saccharides significantly slowed the damage to muscle tissue structures. The assumption was that water replacement hypothesis played a leading role in cryoprotection of frozen shrimp. Furthermore, the homology modeling and molecular dynamics simulations confirmed that the saccharides substituted water molecules around the shrimp myosin surface by forming hydrogen bonds with polar residues of amino acids, thereby stabilizing the structures in the absence of water, leading to an increase in protein stability during frozen storage.

Shared gene structures and clusters of mutually exclusive spliced exons within the metazoan muscle myosin heavy chain genes

Multicellular animals possess two to three different types of muscle tissues. Striated muscles have considerable ultrastructural similarity and contain a core set of proteins including the muscle myosin heavy chain (Mhc) protein. The ATPase activity of this myosin motor protein largely dictates muscle performance at the molecular level. Two different solutions to adjusting myosin properties to different muscle subtypes have been identified so far: Vertebrates and nematodes contain many independent differentially expressed Mhc genes while arthropods have single Mhc genes with clusters of mutually exclusive spliced exons (MXEs). The availability of hundreds of metazoan genomes now allowed us to study whether the ancient bilateria already contained MXEs, how MXE complexity subsequently evolved, and whether additional scenarios to control contractile properties in different muscles could be proposed, By reconstructing the Mhc genes from 116 metazoans we showed that all intron positions within the motor domain coding regions are conserved in all bilateria analysed. The last common ancestor of the bilateria already contained a cluster of MXEs coding for part of the loop-2 actin-binding sequence. Subsequently the protostomes and later the arthropods gained many further clusters while MXEs got completely lost independently in several branches (vertebrates and nematodes) and species (for example the annelid Helobdella robusta and the salmon louse Lepeophtheirus salmonis). Several bilateria have been found to encode multiple Mhc genes that might all or in part contain clusters of MXEs. Notable examples are a cluster of six tandemly arrayed Mhc genes, of which two contain MXEs, in the owl limpet Lottia gigantea and four Mhc genes with three encoding MXEs in the predatory mite Metaseiulus occidentalis. Our analysis showed that similar solutions to provide different myosin isoforms (multiple genes or clusters of MXEs or both) have independently been developed several times within bilaterian evolution.

Cloning of skeletal myosin heavy chain gene family from adult pleopod muscle and whole larvae of shrimps

The physiological and biological properties of skeletal muscle in crustacea have not been well understood compared with those of vertebrates. The present study focused on myosin, the major protein in skeletal muscle, from shrimps. In our previous study, two full-length genes encoding myosin heavy chain (MHC), a large subunit of the myosin molecule, were cloned from abdominal fast skeletal muscle of kuruma Marsupenaeus japonicus, black tiger Penaeus monodon and Pacific white Penaeus vannamei shrimps, and named as MHCa and MHCb. In this study, we renamed these as MHC1 and MHC2, respectively, due to the presence of various isoforms newly identified. Partial MHC sequences were identified from pleopod muscle of these shrimps. Two MHCs, named MHC3 and MHC4, were identified from pleopod muscle of kuruma shrimp, whereas two MHCs, named MHC4 and MHC5, were cloned from Pacific white shrimp pleopod. MHC3 was cloned only from black tiger shrimp pleopod. Partial MHC sequences from zoea, mysis, and postlarvae of black tiger and Pacific white shrimps were also determined. The phylogenetic tree demonstrated that most MHCs from pleopod muscle and larval MHCs formed clades with MHC1 and MHC2, respectively. These MHCs were considered to be of fast type, since MHC1 and MHC2 are fast-type MHCs according to our previous study. MHC5 obtained from pleopod muscle of Pacific white shrimp in this study was monophyletic with American lobster Homarus americanus S2 slow tonic MHC previously reported, indicating that MHC5 from Pacific white shrimp is of slow type.

Cloning, expression, and localization of two types of fast skeletal myosin heavy chain genes from black tiger and Pacific white shrimps

The physiology and biochemistry of skeletal muscles in shrimps have been poorly understood compared with those from vertebrates. The present study was conducted focusing on myosin, the major protein in skeletal muscle, from adult specimens of black tiger Penaeus monodon and Pacific white Penaeus vannamei shrimps. Two genes encoding myosin heavy chain (MHC), a large subunit of the myosin molecule, were cloned from abdominal fast skeletal muscle and defined as MHCa and MHCb according to our previous study on kuruma shrimp Marsupenaeus japonicus. Random cloning demonstrated that the MHCb gene (MHCb) was expressed more abundantly than MHCa. The full-length cDNA clones of MHCa and MHCb from black tiger shrimp consisted of 5,926 and 5,914 bp, respectively, which encoded 1,914 and 1,909 amino acids, respectively, whereas those from Pacific white shrimp consisted of 5,923 and 5,908 bp, respectively, which encoded 1,913 and 1,909 amino acids, respectively. Both MHCa and MHCb were considered to be fast muscle type due to their strict localization in fast muscle. The amino acid identities between MHCa and MHCb of black tiger shrimp were 77%, 60%, and 73% in the regions of subfragment-1 (S1), subfragment-2 (S2) and light meromyosin (LMM), respectively, with 71% in total, whereas those of Pacific white shrimp were 78%, 60%, and 73% in the regions of S1, S2, and LMM, respectively, with 72% in total. In situ hybridization and northern blot analysis using different regions from abdominal muscle demonstrated different localizations of MHCa and MHCb transcripts in this muscle, suggesting their distinct physiological functions.