Shoshi Mizuta

Molecular species of collagen in pectoral fin cartilage of skate (Raja kenojei)

Soluble collagen was prepared from the pectoral fin cartilage of skate (Raja kenojei) by limited pepsin digestion. It was fractionated into three fractions by differential salt precipitation. All collagen fractions were further purified by phosphocellulose column chromatography and were characterized with respect to solubility, mobility on SDS–PAGE, peptide map, and amino acid composition. The resultant data indicate the distribution of three molecular species of collagen, corresponding to Type I and II as major collagens and Type XI as a minor collagen, respectively.

Molecular species of collagen from wing muscle of skate (Raja kenojei)

Abstract Soluble collagen was prepared from skate ( Raja kenojei ) wing muscle by limited pepsin digestion. It was fractionated into two fractions, major and minor, by differential ammonium sulfate precipitation. Two collagen types were purified from the major and minor collagen fractions by phosphocellulose column chromatography and were identified as Type I and V collagens, respectively, by SDS-PAGE, peptide mapping, and amino acid analysis.

Partial characterization of collagen in mantle and adductor of pearl oyster (Pinctada fucata)

Histochemical observation clarified the presence of collagen in the connective tissues of epimysium, perimysium, and endomysium in the mantle and adductor of the pearl oyster Pinctada fucata. A small amount of soluble collagen could be obtained from the mantle and adductor by extracting a crude connective tissue fraction with 4 M guanidine hydrochloride (G/HCl) solution, without protease digestion of telopeptides. The G/HCl-soluble collagen showed two alpha bands (α1 and α2) on SDS–PAGE. The relative staining intensities of the α1 to α2 chains were decreased gradually by pepsin digestion with concomitant development of lower molecular weight components. These results suggest the existence of pepsin-sensitive regions in the triple helical domain of the α1 chain.

Comparison of collagen types of arm and mantle muscles of the common octopus (Octopus vulgaris)

Properties of muscle collagens of arm and mantle of the common octopus, Octopus vulgaris, were compared with regard to molecular species and thermal behaviour. The major collagens were isolated from pepsin-solubilized collagen preparations of these tissues by salt precipitation and were shown, by peptide mapping, to be essentially identical to each other in the triple helical domain. Alpha and beta subunits of the major collagen of the arm, in intact form (not solubilized by pepsin digestion), on electrophoresis, moved more slowly than those of the mantle. The major collagen of the arm showed higher hot-water solubility and lower thermal stability than that from the mantle muscle. These results suggested that there were some structural and functional differences between the major collagens from these tissues although they were genetically identical molecular species. In addition, immunoblot analysis revealed the existence of a minor collagen type, which corresponded to Type SQ-II collagen in decapod molluscs, in both arm and mantle muscles.

Characterization of molecular species of collagen in muscles of Japanese amberjack, Seriola quinqueradiata

Pepsin-solubilized collagens prepared from the muscle tissues (ordinary and dark muscles) of Japanese amberjack were separated into two fractions, major and minor, by ammonium sulphate precipitation. Collagens in these fractions were further purified by cation-exchange column chromatography. The results of SDS-PAGE, peptide mapping, and amino acid analysis suggested that the purified major and minor collagens might be classified as type I and V collagens, respectively. Each type of collagen was fundamentally similar, among the ordinary and dark muscles, in amino acid compositions and peptide maps.

CDNA cloning of Japanese oyster stress protein homologous to the mammalian 78-kDa glucose regulated protein and its induction by heatshock

The 78-kDa glucose regulated protein (GRP78), a member of stress proteins, was cloned from a cDNA library of Japanese oyster Crassostrea gigas. The analysis on Japanese oyster GRP78 clone of approximately 2.6 kb revealed that the entire open reading frame was 1983 bp long and encoded 661 amino acid residues. At the DNA sequence level, the coding region of Japanese oyster GRP78 gene was 72, 62, and 62% identical to those of chicken GRP78, Japanese flounder HSP70, and Japanese flounder HSC71 genes, respectively. Deduced amino acid sequence of Japanese oyster GRP78 was 84, 62, and 62% identical to those of chicken GRP78, Japanese flounder HSP70, and Japanese flounder HSC71, respectively. Japanese oyster GRP78 contained an 18-residue sequence at the N-terminus that exhibits characteristics of a cleavable signal sequence. It also contained an ATPase domain, and a peptide-binding domain in addition to a Lys-Asp-Glu-Leu (KDEL) peptide motif that is involved in determining endoplasmic reticulum localization. Northern blot analysis showed that GRP78 mRNA was induced with heatshock treatment in the oyster tissues.

Existence of two molecular species of collagen in the muscle layer of the ascidian (Halocynthia roretzi)

The molecular species of collagen in the muscle layer of the ascidian Halocynthia roretzi was examined by biochemical techniques. Two types of collagen which showed distinct patterns from each other on SDS-PAGE were isolated from the pepsin-solubilized collagen by differential salt precipitation and phosphocellulose column chromatography. They were demonstrated to be genetically distinct from each other by peptide mapping and by amino acid analysis. These results indicate that at least two molecular species of collagen are present in the muscle layer of the ascidian.

Characterization of the quantitatively major collagen in the mantle of oyster Crassostrea gigas

A quantitatively major collagen was isolated from the pepsin-solubilized collagen preparation of the mantle by differential salt precipitation and phosphocellulose column chromatography, and its constituent α components (α1 and α2) were purified by phosphocellulose column chromatography. The subunits were demonstrated to be genetically distinct from each other by peptide mapping and amino acid analysis. The amino acid composition calculated from those of the α1 and α2 components in 2∶1 ratio coincided well with that of the major collagen from the mantle. These results suggest that the major collagen in the mantle of the oyster may have a heterotrimer structure (α1)2 α2.

Properties of scallop mantle collagen: its content, tissue distribution and thermal behavior

To obtain fundamental information for the effective use of scallop Patinopecten yessoensis mantle, which is one of the underutilized marine resources. Some properties of collagen contained in the mantle were examined by chemical and histochemical techniques. Collagen content in the mantle varied annually, ranging from 0.98 to 1.72% of wet tissue, 7.7 to 12.6% of dry tissue and 13.5 to 26.5% of total protein, being relatively in high level of collagen content of invertebrate muscles. Collagen fiber was densely distributed in the inner connective tissue matrix of the mantle pallial, in contrast to the inner fold part which was rich in muscle fibers. The collagen contained in the crude collagen fraction (residue after alkali extraction), prepared from the mantle, was revealed to have considerably low solubility on hot-water extraction, constantly less than 20% of the total collagen at the temperatures in the range of 20–90°C.

The Taurine Content of Japanese Seaweed

Japanese and South Koreans have a dietary habit of eating seaweed. Although it is known that some seaweed contains taurine, there have been few detailed analyses on the taurine content of seaweed other than the major types of edible seaweed. In the present study, we determined the content of free amino acids, including taurine, in seaweed obtained along the Sea of Japan coast. The taurine content in the seaweed varied according to the species. Among the 29 different types of seaweed that were studied, red algae contained relatively high concentrations of taurine. In contrast, the taurine content was low or undetectable in brown and green algae. The algal alanine level was relatively higher in brown sea algae, which was in sharp contrast to its taurine level. No clear trends were observed with regards to the distribution of the other free amino acids, including aspartic acid, glutamic acid, and phenylalanine. Considering the physiological role of taurine in cellular homeostasis, the algal taurine content may be associated with the growing environment. Taurine-rich red edible algae such as mafunori (Gloiopeltis tenax)/fukurofunori (Gloiopeltis furcata), kabanori (Gracilaria textorii), and ogonori (Gracilaria vermiculophylla) may be used to create functional foods that are rich in naturally occurring taurine.