Raja Kenojei Research Articles

The effect of processing conditions on the properties of gelatin from skate ( Raja Kenojei) skins

Effects of several conditions (liming concentrations, extraction solution pH, extraction temperature and extraction time) to extract gelatin from skate skin on the yield and quality properties were investigated. The optimum conditions for gelatin extraction are as follows; place skin in a lime solution of 1.5% (w/v) calcium hydroxide, extract with three volumes of water (pH 6.0) for 4 h at 50%, filter gelatin through activated carbon (250–350 mesh, 3%) and freeze-dry the colloidal suspension. The functional properties of skate skin gelatin produced by optimum extraction conditions were: gelling point 16.12 °C; melting point 19.30 °C; isoelectric point 6.45; and turbidity 6.98.

한국 거문도연안 세라믹어초어장에서의 홑자망과 삼중자망에 의한 어획성능

홑자망과 삼중자망에 의한 어획성능을 파악하기 위하여 한국 남해안의 거문도연안에 시설된 세라믹 어초어장에서 어구 성능시험과 수중 비디오 카메라로 어군 위집상을 조사로 하였다. 흩자망에 의한 폭당 어획량은 삼중자망에 비해 49.2% 많았으나, 어종수는 34.5% 적었는데, 이를 ANOVA로 분석한 결과 5% 유의수준에서 차이가 없었다. 어구별 우점종은 홑자망에서 참돔 1종, 삼중자망에서 참돔, 말쥐치, 홍어 등 3종이었으며, 홑자망에의해 어획된 참돔의 체장범위와 평균체장은 삼중자망에 어획된 참돔보다 다소 적게 나타났다. 홑자망에 의한 어획성능이 삼중자망보다 높았던 원인은 홑자망에 어획되기 쉬운 어종이 군을 형성하고 있었고, 개체의 크기도 홑자망에 적합하였기 때문이라고 판단된다. It has been, in general, known that the catching efficiency of a trammel net is better than that of a gill net because of the variability of catch species and size. In this stidy, A fishing gear test was carried out to analyze the catching efficiency of the gill net and the trammel net on the coast of Geomun-do of southern Korean waters and fish school aggregation was also investigated using a underwater video camera. CPUE of the gill net was 49.2% higher than the trammel net but fish species was 34.5% lower where there was no difference on the significance level of 5% by ANOVA test. Main catch species caught by the gill net were red seabream(Pagrus major) and triggerfish(Aluterus monoceros), skate ray(Raja Kenojei) and red seabream for the trammel net, and the average body length of red seabream was shorter than the trammel net. It was thought that the reason of higher catch in the gill net than the trammel net was a fish school which can be caught easily by gill net and the size of population was suitable for the gill net.

Nutritional composition and microflora of the fresh and fermented skate (Raja Kenojei) skins

The proximate compositions of fresh and fermented skate skin were each 75.95% and 74.5% moisture, 22.7% and 21.8% protein, 0.5% and 0.7% lipid and 0.6% and 0.9% ash, respectively. The predominant minerals were potassium and phosphorus (i.e. 53.5 and 33.0 mg/100 g in fresh skin, and 10.46 and 10.51 mg/100 g in fermented skin, respectively). Amino acid concentrations were lower in the fermented skin compared with the fresh skin. Histidine, glycine, alanine and glutamic acid were the major free amino acids in both skins. Palmitic acid (C16:0) was the major fatty acid in both fresh (16.68%) and fermented (20.38%) skate skin. Omega-3 polyunsaturated fatty acids were higher in fresh skin (22.17%) and fermented skin (24.54%) compared with omega-6 polyunsaturated fatty acids. The predominant microflora present in the both fresh and fermented skin were Photobacterium sp. and Vibrio sp. Total plate counts for the fresh and fermented skin were 2.4×104 CFU/g and 7.7×107 CFU/g, respectively.

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 )

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.

Structures Immunoreactive with Porcine NPY in the Caudal Neurosecretory System of Several Fishes and Cyclostomes

Abstract Using a double immunostaining technique, we examined the relationships between neuropeptide Y (NPY)- and urotensin I (UI)- and/or urotensin II (UII)-positive structures in the caudal spinal cord of various species of fishes, particularly in the teleost Oncorhynchus masou and in elasmobranchs Scyliorhinus torazame, Triakis scyllium, and Raja kenojei. Primitive actinopterygians, i.e., Acipenser transmontanus, Polypterus senegalus, and Lepisosteus productus, and cyclostomes Lethenteron japonica and Eptatretus atami were also studied from the viewpoint of comparative endocrinology. In the teleost and elasmobranchs, NPY-positive fibers were demonstrated to be often in contact with UI- and/or UII-positive cells and fibers, suggesting a control of the caudal neurosecretory neurons by NPY or a related substance. Similar association was seen in the primitive actinopterygians. As to the cyclostomes, immunoreactivities for NPY and UII were found in the lamprey, but none of the immunoreactivity for these pep...

Occurrence of Neuropeptide Y (NPY)-like-Immunoreactive Cells in the Vitellointestinal Duct and Yolk Sac of Two Species of Elasmobranchs

In order to extend our knowledge on the occurrence of neuropeptide Y (NPY)-like-immunoreactive cells in the vitellointestinal duct and yolk sac of oviparous elasmobranchs, we performed immunohistochemical examination on two species of elasmobranchs, Cephaloscyllium isabellum and Raja kenojei. In both species, NPY-positive cells were demonstrated in the epithelial layer of the vitellointestinal duct and internal yolk sac, as previously reported in Scyliorhinus torazame. In the Cephaloscyllium embryo, NPY-positive cells were sporadically encountered even in the endodermal layer of the external yolk sac proximal to the vitellointestinal duct. These findings support the view that the NPY-positive cell is a common endocrine component in the vitellointestinal duct of oviparous elasmobranchs.

Immunohistochemical localization and biological significance of the phylogenically conserved thymus-brain antigen (UB-13 antigen) in skate, rat and human

A monoclonal antibody (UB-13) originally raised against the brain of the skate ( Raja kenojei, a cartilaginous fish) was found to react with lymphoid and brain tissues from many species when examined immunohistochemically. In rat and human thymus, UB-13 antigen was observed to be closely associated with reticular tissue in the medulla and cortex. Interestingly, a few or several thymocytes were encircled by the UB-13-reactive reticular tissue. At 14 days gestation, rat thymus consisted mainly of reticular epithelial tissue, after which strong thymocyte production started. At this stage, some of the reticular tissue was heavily stained with UB-13. In the thymus tissues of the irradiated and recovering rats, where reduction and massive reproduction of thymocytes were observed, extensive UB-13 antigen expression localized on the reticular epithelial tissue, an observation which may support the thymocyte re-population. These findings suggest that the antigen recognized by UB-13 may be important for thymocyte proliferation and maturation. UB-13 antigen was found in the fibrous structure of the molecular and granular layer of the human cerebellum. Some glial cells were also stained strongly with UB-13 in the human cerebellar or cerebral grey and white matter. In rat, glial cells, especially astroglias, and the endothelial structure of blood vessels were stained strongly with UB-13. These findings suggest that UB-13 may be a useful monoclonal antibody for analysis of brain-lymphoid antigen in many species.

J-chain-like component in 18-S immunoglobulin of the skate Raja Kenojei, a cartilaginous fish

A J-chain was found in the IgM, an 18-S pentameric immunoglobulin, of the skate, Raja kenojei, a cartilaginous fish, by means of gel filtration-column chromatography of reduced and radioalkylated immunoglobulin, followed by alkaline-urea polyacrylamide gel electrophoresis. The J-chain showed an electrophoretic mobility equivalent to that of the light chain, and much slower than that of the J-chain in human IgM. Its electrophoretic banding patterns, however, were different from those of the light chain. Its mol. wt of 17,500 was close to that of mammalian J-chain. The J-chain was not found in another immunoglobulin of the skate, a 9-S dimer held by a noncovalent force. No immunological cross-reactivity was observed between the skate J-chain and human and chicken J-chains. In view of these findings, it was concluded that the J-chain in the skate IgM is both electrophoretically and antigenically considerably different from the J-chain in mammalian IgM.

Ontogenic studies on the appearance of two classes of immunoglobulin-forming cells in the spleen of the Aleutian skate, Bathyraja aleutica, a cartilaginous fish.

We identified the presence in the Aleutian skate, Bathyraja aleutica, of two classes of immunoglobulins (Ig), a high molecular weight Ig analogous to mammalian IgM and a low molecular weight Ig, similarly to the spiny rasp skate, Raja kenojei, (Kobayashi, K. et al., Mol. Immunol. 1984. 21: 397), using an immunological cross-reaction with the specific antisera to the spiny rasp skate Ig components. The antigenic similarity of the heavy chains of the Ig of the Aleutian skate and those of the spiny rasp skate was less than that between their light chains. Two types of Ig-producing cells, one producing the high molecular weight and the other forming the low molecular weight Ig, were present in the spleen of embryos and adults in the Aleutian skate at a ratio of 5-6:4-5. The number of these Ig-producing cells increased with advancing development of the embryos but was 1/20 to 1/50 of those of adults. Cells, each of which were capable of forming both classes of Ig, were found in the spleen of embryos but not in that of adults. These results suggested that the spleen of the Aleutian skate is the primary lymphoid organ for B lymphocyte differentiation and proliferation, possibly equivalent to the bursa of birds.

Two populations of immunoglobulin-forming cells in the skate, [formula omitted]: Their distribution and characterization

We recently reported the presence in the skate, Raja kenojei, of two immunoglobulins, a high molecular weight immunoglobulin analogous to mammalian IgM, and a low molecular weight immunoglobulin belonging to a hitherto undescribed class. In view of these findings, we studied lymphoid organs of the skate using morphological and immunocytochemical means. The spleen and the intestinal mucosa had numerous plasma cells and lymphocytes, while the Leydig organ of the esophagus, the epigonal organ and the liver contained these cells in a much lesser frequency. Immunocytochemical studies proved these plasma cells and some of the lymphocytes to be immunoglobulin-forming cells. Double immunofluorescence staining of the spleen and other lymphoid tissues demonstrated the occurrence at a 1 : 1 ratio of two distinct populations of cells, one forming the high molecular weight immunoglobulin and the other producing the low molecular weight immunoglobulin.

A second class of immunoglobulin other than IgM present in the serum of a cartilaginous fish, the skate, Raja kenojei: Isolation and characterization

A second class of immunoglobulin, in addition to a pentameric immunoglobulin analogous to mammalian IgM, was found in the serum of a cartilaginous fish, the skate. Raja kenojei. The immunoglobulin was a non-covalently associated dimer with a sedimentation coefficient of 8.9 S and a mol. wt of 320,000. Its heavy chain had a mol. wt of 45,000–50,000, smaller than that of the heavy chain (mol. wt 70,000) of the skate IgM, and had its own specific antigenic determinants. The immunoglobulin was synthesized in plasma cells different from those that produced the IgM. These results provide evidence that, contrary to the prevailing view, the divergence of immunoglobulin class occurred as early in evolution as the cartilaginous fish, a primitive vertebrate.