• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.24 no.5
• /
• pp.273-288
• /
• 1991

To elucidate the physiological and biochemical differences between chondrichthyes and osteichthyes, the properties of the specific digestive enzymes in cat-shark, Cephaloscyllium umbratile, and mackerel, Scomber japonicus, were studied. Homogenous trypsin proved through the disc-electrophoresis, SDS-PAG electrophoresis and gel filtration was obtained from the pancreas of cat-shark by $50-70\%$ saturated ammonium sulphate fractionation, DEAE-Sephadex A-50 column chromatography, benzamidine-Sepharose 6B affinity chromatography and Sephadex G-75-120 gel filtration. Two types of trypsins were also obtained from the pyloric caeca of mackerel by $30-70\%$ saturated ammonium sulphate fractionation and the slightly modified procedure from the method adopted in the purification of cat-shark trypsin. The two trypsins, designated trypsin A and B, were proved their homogeneity by disc- and SDS-PAG electrophoresis and gel filtration. The molecular weights of the trypsins were estimated to be 31,700 for cat-shark trypsin, 30,000 for mackerel trypsin A and 29,000 for mackerel trypsin B by SDS-PAG electrophoresis, but those were estimated to be 21,500 for cat-shark trypsin, 23,700 for mackerel trypsin A and 21,500 for mackerel trypsin B by gel filtration. The trypsins exhibited their optimum conditions at pH 9.0 and on temperature ranged from $45^{\circ}C\;to\;50^{\circ}C$ for cat-shark, and at pH 8.0 and a temperature of $50^{\circ}C$ for mackerel trypsin A and B, respectively. The cat-shark trypsin was stable at pH 10.0 and the temperature below $10^{\circ}C$, whereas the mackerel trypsin A and B, were stable in the range over pH 7.0 to pH 9.0 below $10^{\circ}C$ and at pH 8.0 below $35^{\circ}C$, respectively. The mackerel trypsins were severely inhibited by some heavy metal ions such as $Ag^{2+},\;Cu^{2+}\;and\;Hg^{2+}$ compared to cat-shark trypsin. All of the enzymes were also inhibited by antipain, leupeptin, TLCK(tosyllysine chloromethyl ketone) and SBTI(soybean trypsin inhibitor) remarkably. The inhibitory effects of PMSF(phenylmethane sulphonylfluoride), DFP(diisopropyl fluorophosphate) and benzamidine were indicated that these enzymes belong to serine-proteases.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.16 no.2
• /
• pp.147-153
• /
• 1983

To check the differences of the digestive enzymes by the bait habits and the proteolytic activities of the fissile extracts from the fish, omnivorous filefish (Navodon modestus), carnivorous cat shark (Scilliorhinus tarazame) and bloodsucking hag fish (Eptatretus burgeri) were sampled for this experiment. The activity of crude alkaline protease extracted from the muscle and the internal organs of the samples was determined with casein as substrate. The activity of the proteolytic enzymes showed remarkable differences by the organs of the fish. The optimum condition of the pretenses from the muscle revealed in range of pH 7.8-8.3, at $60-65^{\circ}C$, while those of the enzymes from the internal organs were at about pH 8.2, $45-55^{\circ}C$, but those of hag fish were at about pH 6.7, $45-55^{\circ}C$. The proteolytic activity of the enzyme of alimentary canal in filefish and in hag fish was 57 and 11 times stronger than that of muscle, respectively. The crude enzyme from the alimentary canal of file fish showed the strongest proteolytic activity in samples submitted and that of cat shark was the lowest. The activity of pancreatic alkaline protease in cat shark was 50 fold higher than that of muscle alkaline protease in the fish.

• Korean Journal of Veterinary Research
• /
• v.31 no.1
• /
• pp.27-32
• /
• 1991

The pancreatic endocrine cells of the cat-shark, S. torazame, were studied using immunohistochemical method. Five kinds of endocrine cells (glucagon-, somatostatin-, insulin-, 5-HT-and BPP-immunoreactive cells) identified in this study. The chracteristic findings of the distributions of five immunoreactive cells were as follows. Glucagon-immunoreactive cells were detected as clustering group in the epithelia of the interlobular duct and singly the pancreatic acini, respectively. Insulin -immunoreactive cells were moderately observed in the epithelia of the interlobular duct or in the periphery of the islet. Somatostatin-immunoreactive cells were distributed in single or mass groups in the epithelia of the interlobular duct and the exocrine gland of the pancreas. A very few 5-HTimmunoreactive cells were seen in the periphery of the islet and the acini of the pancreas-BPP-immunoreactive cell was singly located in the periphery of the pancreatic islet, but GAS/CCK-and Chromogranin-immunoreactive cells were not found in this study.

• Korean Journal of Veterinary Research
• /
• v.35 no.3
• /
• pp.417-425
• /
• 1995

The regional distribution and relative frequencies of gastrointestinal endocrine cells were studied immunohistochemically in the GIT of the cat-shark. Five kinds of endocrine cells were identified in this study. Mostly these cells were of open types, except for glucagon-, BPP- and somatostatin-immunoreactive cells in the stomach which seemed to be of closed type. 5-HT-immunoreactive cells were detected throughout the GIT, and were more freguent than of the other regions. Glucagon-and BPP-immunoreactive cells were demonstrated in the entire GIT except for the duodenum an the rectum, and occurred in various frequencies. A few numbers of Gas/CCK-immunoreactive cells were restricted to the duodenum. Somatostatin-immunoreactive cells were distributed in the whole GIT, and were a few in numbers in the stomach and rare in the intestine, respectly. These results suggest that the pattern of the regional distribution is rather similar to that reported fur previously, but relative number was less frequent than that of other species.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.14 no.2
• /
• pp.59-65
• /
• 1981

The purpose of the present study is to find the light intensity which induces maximum gathering rate and to observe the variation of the gathering rate both in daytime and at night by rising two species of commercial fishes: gray rock cod. Sebastes inermis (Cuvier et Valenciennes) and cat shark, Scyliorhinus torazame (Tanaka). An experimental tank $(360L\;{\times}\;50W\;{\times}\;55H\;cm)$ was set up in a dark room. An illumination system was attached to one end of the tank to control horizontal light intensity. Six artificial light sources were prepared by combination of two light bulbs (5W, 150W) and seven filters. During the experiment water depth was maintained 50 cm level in the tank. The tank was marked into six longitudinal sections each being 60 cm long to observe the distribution of fish. The fish were acclimatized in dark condition for 40 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 40 times every 30 seconds, and the gathering rates were obtain from the average number of fish in each section. The light intensity inducing maximum gathering rate is as follows: gray rock cod: 16.6 lux (10.6-24.5 lux) (day), 0.7 lux (0.5-1.1 lux) (night), cat shark: 1.9 lux (1.2-2.9 lux) (day), 16.6 lux(10.6-24.5lux) (night). Trend of the gathering rate in illumination time revealed different results in two fish species. Gathering rate of gray rock cod did not show any definite pattern but fluctuated irregularly. The gathering rate was some fluctuating at night. However, that of cat shark was almost constant and did not show any distinctive difference between day and night.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.19 no.1
• /
• pp.12-16
• /
• 1983

The author carried out an experiment to find out the response of cat shark, Scyliorhinus torazame(Tanaka) to the colored lights. The experimental thank (360L$\times$50W$\times$55H cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe th location of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The favorite color of the fish was found in the order of yellow, white, blue and red in day time, and red, blue, white and yellow at night time. The variation of the gathering rate on illumination time was very little and showed more stability in day time than at night time. The differences of the gathering rates to two selected colors out of the four colors were greater regardless of illumination time.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.25 no.5
• /
• pp.383-391
• /
• 1992

A comparative study of enzymatic properties between the trypsin from the cat-shark Cephaloscyllium umbratile ( C-T) and the two trypsins from the mackerel Scomber japonicus $(M-T_A\;and\;M-T_B)$ was carried out following after the previous paper(Pyeun et al., 1991). Trypsin from cat-shark(C-T) showed the higher heat stability compared to the others $(M-T_A\;and\;M-T_B)$ and its denaturation constant$(K_D)$ was $10.68\times10^{-4}\;sec^{-1}\;at\;55^{\circ}C$ with BA-p-NA substrate. The activation energies(Ea) of the trypsins measured at a temperature range from $30^{\circ}C\;to\;50^{\circ}C$ were estimated to be 4.07 kcal/mole for C-T, 11.61 kcal/mole for $M-T_A$, and 8.43kcal/mole for $M-T_B$, respectively. The Km values were $24.9\times10^{-5}\;M\;for\;C-T,\;5.37\times10^{-5}\;M\;for\;M-T_A,\;and\;9.65\times10^{-5}\;M\;for\;M-T_B$. On the other hand, the Ki values for TLCK and DFP determined by Dixon plot were $1.50\times10^{-6}\;M\;and\;9.28\times10^{-6}\;M\;for\;C-T\;2.86\times10^{-6}\;M\;and\;2.11\times10^{-4}\;M\;for\;M-T_A\;and\;3.90\times10^{-6}\;M\;and\;1.60\times10^{-4}\;M\;for\;M-T_B$ Similar amino acid profiles were showed between three trypsins each other, with few exceptions of $M-T_B$ containing higher amount of arginine, and the smaller amount of tryptophan in C-T than the others.