Fisheries science
Print ISSN : 0919-9268
Volume 64 , Issue 5
Showing 1-39 articles out of 39 articles from the selected issue
  • Seiji Ohshimo, Takumi Mitani, Satoshi Honda
    1998 Volume 64 Issue 5 Pages 665-672
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    Biomass of Japanese sardine Sardinops melanostictus was estimated using a quantitative echo sounder (Furuno, FQ-70; 50kHz) from 1990 to 1994 in the waters off western and southern Kyushu, in southwestern Japan, and the relative estimation error was calculated by geostatistics (1-D transitive theory). Sea surface water temperature and current vectors were measured using an electrical thermometer and ADCP (acoustic doppler current profiler), respectively. The estimated biomass of Japanese sardine using -31.5dB/kg of target strength was over 10 million metric tons in 1990, however, the estimated biomass was continuously decreasing. The estimated biomass was about 100 thousand tons in 1994. The distribution pattern of Japanese sardine was changed with biomass strength. In large biomass phase, Japanese sardine was widely distributed over the survey area, but restricted on the neritic area in small biomass phase.
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  • Kenji Saitoh
    1998 Volume 64 Issue 5 Pages 673-679
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    This study deals with local differentiation in Pacific cod among three Japanese coastal areas around putative reproductive sites and the western Bering Sea. Restriction and SSCP analyses conducted on the mitochondrial control region showed genetic divergence between some Japanese coastal areas and the Bering Sea. RAPD analysis also indicated divergence between Japanese coastal areas and the Bering Sea. mtDNA analysis revealed low variability and no local distinction among Japanese localities. Calculating gene frequency data sets by two different ways, RAPD markers showed accordance between genetic and geographic distances in Japanese coastal areas.
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  • Takashi Tada, Ikuo Hirono, Takashi Aoki, Fumio Takashima
    1998 Volume 64 Issue 5 Pages 680-685
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    Activins are dimeric proteins that belong to the transforming growth factor-β superfamily. Using the polymerase chain reaction (PCR), we have cloned and sequenced activin βA and βB genes, which encode the mature region of the peptides, from carp and medaka genomic DNA. The carp activin gene that codes for one type of βA and three types of βB was isolated from carp genomic DNA. *3Similarly, the medaka activin gene that codes for two types of βA and one type of βB was isolated from medaka genomic DNA. *4High identities were found to exist between these subunits and their mammalian counterparts. The carp βA subunit has 75.5% nucleotide sequence identity with the human βA subunit and the three carp βB subunits more than 84% with the human βB subunit. The two medaka βA subunits have greater than 73.5% nucleotide sequence identity with the human βA subunit, while the medaka βB subunit exhibits 84% sequence identity with the human βB subunit.
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  • Kouji Kooka, Tetsuya Takatsu, Yoshihiko Kamei, Toshikuni Nakatani, Toy ...
    1998 Volume 64 Issue 5 Pages 686-693
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    Vertical distributions of adult walleye pollock Theragra chalcogramma and oceanographic conditions were examined in the northern Japan Sea. In the daytime, most walleye pollock were distributed from 150 to 250m depth in April and from 400 to 500m depth in October. Between 150 and 500m depth, temperatures in October (0.4-8.8°C) were similar to those in April (0.5-5.4°C), salinity levels were fairly uniform in both months (34.0-34.2 PSU), and dissolved oxygen concentrations were 4.6-6.1ml/l in April and 4.7-6.4ml/l in October. The main foods of walleye pollock in April were the amphipod Themisto japonica, the euphausiid Thysanoessa longipes, and the chaetognath Sagitta elegans. Daytime weighted mean depths of T. longipes were significantly greater in October than in April. Biomass of T. longipes in the habitat of walleye pollock was significantly greater than other layers in both months. The seasonal change in vertical distribution of walleye pollock is presumably related to food availability of T. longipes.
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  • Takashi Yada, Fuminari Ito
    1998 Volume 64 Issue 5 Pages 694-699
    Published: 1998
    Released: June 30, 2008
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    Sexual differences in survival and changes in plasma ion levels after transfer from neutral water to acid water prepared with sulfuric acid were examined in medaka Oryzias latipes. In acid water at pH 3.5 and 3.8, survival of female fish was better than male. During exposure to acid water at pH 4.1, there was no mortality in either sex. Male fish showed a transient decrease in the plasma sodium level 24 h after transfer to pH 4.1, whereas there was no change in the female. The plasma level of sulfate was not affected in the female, but a significantly high level was consistently observed during the exposure in the male. In both sexes, the activity of gill Na+, K+-ATPase increased within 24 h after transfer to pH 4.1, and this high level was maintained for 1 month. Treatment with short day-photoperiod (8L:16D) caused a cessation of spawning due to inactivation of the testis and ovary. Transfer to acid water caused a decline in plasma sodium only in male fish, but not in female even under a short photoperiod. These results indicate that female medaka are more tolerant to acidic environment, possibly with a greater osmoregulatory ability than male fish.
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  • Young Chang Sohn, Yasutoshi Yoshiura, Makito Kobayashi, Katsumi Aida
    1998 Volume 64 Issue 5 Pages 700-706
    Published: 1998
    Released: June 30, 2008
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    Water temperature and the nutritional status of individual fish have a profound effect on the reproductive activities that are mainly mediated by the brain-pituitary-gonad endocrine system. In order to investigate the influence of environmental factors on the expression of gonadotropin (GTH) and thyrotropin (TSH) subunit genes in the pituitary, we examined the effects of temperature manipulation and a limitation of food on mRNA levels for GTH I, GTH II, and TSH subunits in sexually mature female goldfish by Northern blot analysis. After fish were acclimated at 20°C, the fish were maintained at either 10, 20, or 30°C for two weeks. The mRNA levels for the a and GTH Iβ subunits were observed to be higher at 10°C than at 20 or 30°C. In contrast, mRNA levels for the GTH IIβ subunit were not different at those temperatures. Low levels of TSHβ mRNA were observed in fish held at 30°C compared to those held at 10 and 20°C. Although fish were unfed for two weeks, no marked differences were observed in mRNA levels of all the GTH and TSH subunits between unfed and fed fish. These data suggest that, in mature female goldfish, low temperature has a stimulating effect on expressions of α, GTH Iβ, and TSHβ genes, and a limitation of food has no significant effect on expression of the examined GTH and TSH subunit genes at least during two weeks.
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  • Naohiko Watanuki, Shohei Kaneuchi, Takayasu Fujita, Toru Iwashita, Gun ...
    1998 Volume 64 Issue 5 Pages 707-710
    Published: 1998
    Released: June 30, 2008
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    In the present study, trapping experiments and observations on the behavior of immature cuttlefish Sepia esculenta towards the traps were made under field and laboratory conditions. Trapping experiments clearly demonstrated the entry of immature cuttlefish into the basket traps. The entry rate was significantly higher in immature than in mature cuttlefish studied in the same laboratory conditions. When entering and leaving the trap, cuttlefish swam straight primarily with arms in front, thus suggesting their active movement. After entry, cuttlefish remained stationary at the bottom. Females stayed in the trap longer than 3 days, while males left within 3 days. The existence or the position of branches did not influence the entry of cuttlefish into the traps. These results may rule out the possibility that spawning is a motivation for the entry of cuttlefish into the traps.
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  • Ken-Ichi Hayashi, Jung Nyun Kim
    1998 Volume 64 Issue 5 Pages 711-714
    Published: 1998
    Released: June 30, 2008
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    In spite of its ecological and commercial significance, the taxonomy of the Crangon affinis complex has been much confused and requires a thorough revision. The specimens from Japanese waters which were previously referred to C. affinis or other closely related taxa have been reexamined. The type material of C. affinis is no longer extant, and a specimen from Yokosuka, Japan, referred to C. vulgaris by Bate (1888), has been selected as a neotype of C. affinis. It has been shown that C. consobrinus De Man is a junior subjective synonym of C. affinis. As a first step for a revision of Crangon in Far Eastern seas, the neotype is described in detail with figures.
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  • Young Chang Sohn, Yasutoshi Yoshiura, Makito Kobayashi, Katsumi Aida
    1998 Volume 64 Issue 5 Pages 715-721
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    In order to clarify the role of gonadal sex steroids in the expressions of gonadotropin (GTH) subunit genes in goldfish, we examined the effect of testosterone (T), estradiol-17β (E2), and 11-ketotestoster-one (11-KT) on the pituitary mRNA levels of GTH Iβ, GTH IIβ and α subunits by Northern blot analysis in male and female fish at sexually early recrudescent and mature stages. Fish were implanted with a blank Silastic capsule, or capsules containing T, E2, or 11-KT (200 μg), and kept at 20°C for 2 weeks. In early recrudescent fish (GSI: male, 2.6±0.2; female, 2.6±0.6), the mRNA of GTH Iβ in T, E2, or 11-KT implanted fish showed significantly lower levels than those in the blank implanted fish in both sexes. The mRNA levels of GTH IIβ in T and E2 implanted fish showed slightly increased levels whereas decreased levels were observed in 11-KT implanted fish in both sexes. The mRNA levels of the α subunit in 11-KT and E2 implanted females were lower than those in the blank implanted females, but no differences were observed in males. In sexually mature fish (GSI: male, 3.5±0.3; female, 7.5±1.5), no clear effects of T, E2, and 11-KT were observed on the mRNA levels of the all GTH subunits except for an increased level of GTH IIβ in E2 implanted males. Thyrotropin β subunit mRNA levels were also measured in these fish but showed no clear changes by steroid hormone treatment except for a decrease by 11-KT and E2 treatments in sexually early recrudescent females. These results indicate that the expressions of GTH Iβ and IIβ subunit genes are differentially regulated by sex steroids in the goldfish at the early recrudescent stage. The results also suggest that the responsiveness of GTH gene expression to sex steroids differs depending on gonadal maturity.
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  • Kenji Sakamoto, Eiji Okimasu, Akinori Amemura
    1998 Volume 64 Issue 5 Pages 722-726
    Published: 1998
    Released: June 30, 2008
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    The dietary value of rotifers Brachionus rotundiformis cultured with Synechocystis sp. SY-4 (S-rotifer) or rotifers secondary-cultured with Nannochloropsis oculata for 24h after culturing with Synechocystis sp. SY-4 (SN-rotifer) was compared with those cultured with N. oculata (N-rotifer) by feeding these rotifers to the larvae of red sea bream Pagrus major and Japanese flounder Paralichthys olivaceus. The growth and survival rates of those fishes fed on SN-rotifers were better than those fed on S-and N-rotifers. The proximate composition of rotifers was significantly different depending on the algal species used for the culture and the mode of culture. The difference in growth and survival rates among the fish larvae might be due to the difference in the content of n-3 highly unsaturated fatty acid (n-3 HUFA) in the feeds. The percentages of n-3 HUFA in the total fatty acids of S-, SN-, and Nrotifers were 10.3, 23.6, and 20.8%, respectively. The amount of n-3 HUFA in S-rotifer was not enough (0.2%/rotifer dry-weight) as feed for the larvae, but the amount was enhanced by secondaryculture with N. oculata (1.0%/rotifer dry-weight) which was higher than that in N-rotifers (0.5%/rotifer dry-weight).
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  • Keiichi Mushiake, Kazutoshi Kawano, Takashi Kobayashi, Tetsuo Yamasaki
    1998 Volume 64 Issue 5 Pages 727-731
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The present study was performed to examine the combined effects of photoperiod control, namely one-month short-day treatment followed by long-day treatment and water temperature control (≥19°C) on ovarian maturation and HCG-induced spawning in yellowtail. In experiments conduced in 1995 and 1996, the daylength was set to 8 hours (8L-16D) for one month followed by a 10 hour extension to 18 hours daylength (18L-6D) for the next month under controlled water temperature before injection of human chorionic gonadotropin (HCG).
    Female yellowtail broodstock kept under both conditions of controlled photoperiod and water temperature were induced to mature more rapidly than those kept under natural conditions. Neither controlled condition of photoperiod nor water temperature was sufficient to induce the maturation of yellowtail. In both years, only fish kept under both conditions controlled were able to spawn in advance of February. Consequently, manipulations of the photoperiod and water temperature are effective in accelerating the maturation of female yellowtail broodstock and for obtaining an early egg collection from yellowtail treated with HCG.
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  • Atsuko Yamaguchi, Toru Taniuchi, Makoto Shimizu
    1998 Volume 64 Issue 5 Pages 732-739
    Published: 1998
    Released: June 30, 2008
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    Geographic variations in growth of the starspotted dogfish Mustelus manazo from five localities off Japan and Taiwan were examined from centrum analysis using soft x-radiography. Based upon seasonal centrum edge analysis, dark rings were formed annually, during the period of June and July in all localities. It was suggested that ring formation did not vary among localities, although seasonal variations in water temperature differed among localities. Great variations in maximum ages among localities were found. The differences in maximum ages between the northernmost population, Aomori, and southernmost population, Taiwan, were almost two times for both sexes (male, 5-9; female, 9-17). Females grew to a larger size than males and were apparently longer-lived in all localities. The significant sexual differences in growth were found in Maizuru and Shimonoseki. For both sexes, Aomori was the largest length at each estimated age in five localities, and Taiwan was the smallest. The growth differed in all localities for males and most localities for females significantly, however, for females, no significant differences between Tokyo Bay and Shimonoseki, and Tokyo Bay and Taiwan were found. The specimens tended to grow larger and have longer life span in the eastern and northern areas, however, the water temperature may not be a major factor for differences in growth.
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  • David H. Secor, Taro Ohta, Koji Nakayama, Masaru Tanaka
    1998 Volume 64 Issue 5 Pages 740-743
    Published: 1998
    Released: June 30, 2008
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    Japanese sea bass Lateolabrax japonicus is a common euryhaline marine fish distributed in eastern Asian coastal waters, of which life history can be characterized by occasional or seasonal entry to freshwater habitats. Otolith microanalysis for Sr: Ca ratio by a wave-length dispersive electron microprobe was utilized to determine life history trajectory of the Japanese sea bass distributed in Ariake Sea. Laboratory-raised sea bass juveniles which were maintained at various constant salinity regimes and serially decreasing-increasing salinity conditions showed that Sr:Ca ratio was significantly lower in fishes exposed to freshwater than in those to brackish and sea water over salinity 10 ppt. Sr:Ca ratio chronology of a yearling collected in the Chikugo River estuary of Ariake Sea located in western Japan, revealed that fish had immigrated to freshwater habitat during the early life stage and moved between freshwater and estuarine areas. An adult sea bass captured around a spawning ground was confirmed to migrate seasonally into freshwater area by Sr:Ca ratio chronology. These findings validated that otolith microanalysis is a useful tool to determine life history trajectory for Japanese sea bass from very early life through adult stages.
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  • Kanako Watanabe, Hideo Aoki, Youichi Hara, Yoshihiro Ikeda, Youichi Ya ...
    1998 Volume 64 Issue 5 Pages 744-752
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    This study was conducted to determine the energy and protein requirements of yellowtail to optimize feeding levels during the winter season when they have comparatively low feeding activity. Two feeding experiments were conducted during the winters of two subsequent years in net cages located in different environmental conditions at Mie and Nagasaki prefectures, Japan. At both the locations, commercial soft-dry pellets (SDP) with known digestible energy (DE) and protein (DP) values were fed to 4 groups of fish at satiation levels for 5, 3, 2, and 1 time (s) per week.
    In the first experiment, feeding either 2 or 3 times per week produced the best growth offish in Mie prefecture while in Nagasaki prefecture these rations gave the most efficient whole body energy and protein retention. The daily feeding rates (DFR) for the respective feeding frequencies were 2.5-3.7% and 1.3-1.6% in Mie and Nagasaki prefectures. Based on this data, the daily DE and DP requirements per kg body weight for a maximum growth were 43.1-45.1 kcal (180-187kJ) and 4.0-4.2g in Mie and for maintenance of body energy and nitrogen balance 18.5-23.0 kcal (77-96kJ) and 1.7-2.1g in Nagasaki.
    In the second experiment, in both the prefectures the fish fed 3 times per week showed higher growth and feed gain ratios, closely followed by the fish fed 2 times. DFR for these feeding frequencies were almost similar to those obtained in Expt. -I; 2.0% for Mie and 1.2% for Nagasaki fish. The daily DE and DP requirements per kg body weight for a maximum growth were 36.1 kcal (151kJ) and 3.6g in Mie and 21.0 kcal (88kJ) and 2.1g in Nagasaki.
    The differences between the two locations were postulated to be due to the disparity in feed intake which was governed by water temperature.
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  • Tomoko Nomura, Katsutoshi Arai, Taiga Hayashi, Ryo Suzuki
    1998 Volume 64 Issue 5 Pages 753-758
    Published: 1998
    Released: June 30, 2008
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    Sex ratio was 1:1 in normal diploid loach Misgurnus anguillicaudatus reared at a temperature of 20°C, but significant deviation of the ratio to the male was found when reared 25 and 30°C for 214 days from day 6 after hatching. In gynogenetic diploids which were considered genetic females, no males were observed at 20°C. In contast, gynogenetic males and intersexes were observed in groups reared at high temperatures (25 and 30°C) for 220 or 240 days from day 11 after hatching. Incubation of gynogens at 28°C for one month from day 11 after hatching was sufficient to produce males in gynogenetic diploids. These results indicated that high water temperature influences the sex of genetic females in the loach and then induces sex reversal to physiological males.
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  • Robert Vassallo-Agius, Takeshi Watanabe, Keiichi Mushiake, Kazutoshi K ...
    1998 Volume 64 Issue 5 Pages 759-765
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    This study was carried out to investigate the relationship between the composition of broodstock diets and the chemical components of eggs and larvae produced. Two groups of striped jack were used to investigate the effect of two diets, a raw fish mix diet (RF) and a commercial soft-dry pellet diet (cSDP).
    Proximate composition of the diets showed the RF diet to be a protein rich diet and the cSDP diet to be a high energy diet on a dry matter basis. Lipids, polar and non-polar lipids, fatty acids, vitamin E, and carotenoid contents were analyzed for buoyant eggs and subsequent larvae produced.
    Eggs and larvae obtained throughout the spawning period showed fatty acid patterns typical of marine eggs and larvae. Broodstock fed on cSDP produced eggs and larvae with a higher eicosapentaenoic acid (EPA) content and a lower docosahexaenoic acid (DHA) content than those produced from the RF group. The percentage of non-polar lipids in eggs obtained from the cSDP group was slightly higher, and vitamin E contents were similar. Although both diets contained carotenoids, no carotenoids were detected in any of the eggs or larvae sampled.
    Total lipids, fatty acid profiles, and lipid classes of the eggs produced were related to their availability in the diets, indicating the importance of pre-spawning nutritional regimes for striped jack.
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  • Shin-Jung Lin, Tuu-jyj Chai, Sen-Shyong Jeng, Deng-Fwu Hwang
    1998 Volume 64 Issue 5 Pages 766-770
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    To monitor toxicity of cultured puffer Takifugu rubripes specimens were monthly collected from two aquacultural farm in Ilan County and one farm in Taipei County from November 1996 to October 1997. These specimens were dissected into various parts, and their toxicity was determined by the standard tetrodotoxin bioassay. All specimens collected from Ilan County were non-toxic (<10MU/g), while the specimens collected from Taipei County during the period from January to March 1997 showed toxicity in the ovary and liver. The toxicity was as follows: ovary 105±9 (mean±S. E.) MU/g and liver 13±3MU/g in January, ovary 88±12MU/g in February, and ovary 253±55MU/g and liver 17±6MU/g in March. The highest toxicity of ovary and liver was 624MU/g and 119MU/g, respectively. Further, among ten specimens of the flatworm Stylochus orientalis collected from the Taipei's farm in February 1997, four worms showed low toxicity (1-3MU/specimen). Flatworms contained TTX-related substances as analyzed by HPLC and GC-MS.
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  • Seiichi Ando, Eriko Wada
    1998 Volume 64 Issue 5 Pages 771-775
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    We examined the changes in plasma lipoprotein profiles during the long-term starvation of carp. The carp could survive for 150 days without food, during which time they lost 20% of body weight. Starvation was accompanied by a significant decrease of lipoprotein-free components in their plasma. The carp prior to starvation possessed very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein-3 (HDL3) in their plasma, and HDL3 was the main component. The plasma VLDL concentration decreased rapidly reflecting low triacylglycerol levels in the liver of starved carp, while the plasma concentrations of LDL and HDL3 remained almost constant throughout the starvation process. Starvation affected the lipid compositions of LDL and HDL3, and cholesterol ester was substituted for triacylglycerol as main core lipid in these lipoproteins.
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  • Yoshio Kaminishi, Masahiko Kunimoto, Hidemasa Miki, Jun-ichi Nishimoto
    1998 Volume 64 Issue 5 Pages 776-779
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The effects of urea concentration on the gel forming ability of shark muscle were investigated at two characteristic temperatures: aggregation was measured at 40°C; and gelation was measured at 70°C. When heated to 40°C, the gel rigidity of myosin B decreased when the urea concentration was less than or equal to 1.0M, but it increased when the urea concentration was between 1.0 and 2.0M. The increase of gel rigidity can be attributed to the formation of an apparent network structure resulting from increasing disulfide bond levels. When heated to 70°C, the rigidity decreased as the uniform network structure broke down with the increase of urea concentration. The microscopic observation and water distribution analysis revealed that the combined denaturing action of urea and heating resulted in a porous gel with a compact configuration and condensed myosin B network structure.
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  • Masataka Saito, Naomichi Kunisaki, Ikuo Hirono, Takashi Aoki, Masami I ...
    1998 Volume 64 Issue 5 Pages 780-786
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The major fibrillar collagen of rainbow trout skin, type I, was found to have a subunit composition of α1 (I) α2 (I) α3 (I); α3 (I) is known to be a unique subunit of bonyfish type I collagen. To investigate the primary structure of these α (I) chains, a cDNA library was prepared from mRNA of rainbow trout fibroblast and screened by use of a cDNA collagen probe. Three distinct cDNAs coding for fibrillar collagen proα chains were cloned and polypeptides encoded by these clones were denoted as RtCOL1A1, RtCOL1A2, and RtCOL1A3. Each clone encompassed 2.5 or 3.0kb and was found to code for more than the C-terminal half of proα chains. On the other hand, the α1 (I), α2 (I), and α3 (I) chains of rainbow trout skin type I collagen were isolated and characterized by sequencing of selected tryptic peptides with subsequent comparison of these sequences with the deduced amino acid sequences of rainbow trout collagen cDNAs. From these results, RtCOL1A1, RtCOL1A2, and RtCOL1A3 were identified as parts of the proα1 (I), proα2 (I), and proα3 (I) chains of rainbow trout type I collagen, respectively. When compared with human fibrillar collagens, each of RtCOLlA1 and RtCOLlA3 was found to have the highest level of amino acid sequence homology to human proα1 (I), while RICOL1A2 had the highest homology to human proα2 (I). Furthermore, RtCOL1A3 resembled RtCOL1A1 rather than RtCOL1A2; particularly, distribution of the highly conserved cysteine residues and putative crosslinking sites indicated that RtCOL1A3 was diverged from RtCOL1A1. As far as we know, this study is the first report of fish type I collagen cDNAs.
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  • Kuniko Yamaguchi, Yoshiya Izumi, Manabu Kitamikado
    1998 Volume 64 Issue 5 Pages 787-792
    Published: 1998
    Released: June 30, 2008
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    β-Xylosidase was purified from the culture fluid of a bacterium, Bacillus sp. XY-131, by ammonium sulfate precipitation and successive column chromatographies. The final enzyme preparation showed a single protein band on SDS-PAGE. The enzyme's molecular mass was 172kDa as estimated by sucrose density gradient ultracentrifugation and 180kDa as estimated by gel-filtration chromatography. SDS-PAGE suggested that the enzyme molecule was a trimer with a subunit molecular mass of 61kDa. The purified enzyme had a pI of 4.70, a pH optimum of 6.5, and was stable within a pH range of 5.5-7.5 and at temperatures below 55°C. It hydrolyzed p-nitrophenyl-β-D-xylopyranoside with a Km of 0.25mM and showed no activity against other p-nitrophenylglycosides containing p-nitrophenyl-α-D-xylopyranoside. The hydrolysis product from xylobiose, xylotriose, and xylotetraose was xylose. Xylopentaose was cleaved to xylose and a small amount of xylotetraose. Bacillus sp. XY-131 produced β-1, 4-xylanase besides β-xylosidase. These two enzymes were completely separated by DEAE-Toyopearl 650M column chromatography.
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  • Makio Asakawa, Yoshiko Sadakata, Toshiyoshi Araki, Toshihisa Sumi, Hir ...
    1998 Volume 64 Issue 5 Pages 793-797
    Published: 1998
    Released: June 30, 2008
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    Bacillus sp. N4 strain was isolated from the skin mucus of horse mackerel Trachurus japonicus. A protease was purified to homogeneity from the culture fluid by application of ammonium sulfate precipitation, gel nitration, and ion-exchange chromatography. The enzyme (N4-protease) had a single polypeptide chain with apparent molecular weight of 28, 000 estimated by SDS-PAGE, and an isoelectric point around 9.5. The enzyme was most active toward azocasein and Suc-Leu-Leu-Val-Tyr-MCA at pH 10 and toward casein at pH 11, and was stable between pH 6 and pH 11. The optimum temperature of the enzyme was 50°C and its activity was stable below 50°C. Calcium ion was effective to activate and stabilize the enzyme especially at high temperature. Since the activity was completely inhibited by PMSF and DFP but not by sulfhydryl and metal chelating agents, it was concluded that N4-protease is an alkaline serine protease belonging to a member of the subtilisin family.
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  • Koji Inoue, Katsuji Morioka, Itaru Shioya, Toru Mitsuboshi, Yoshiaki I ...
    1998 Volume 64 Issue 5 Pages 798-803
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    Deep seawater (DSW) under the euphotic layer is cool and constant in temperature, rich in inorganic nutrients but contains less organic matter and microorganisms than surface seawater (SSW). We reared red sea bream Pagrus major in DSW, SSW and SSW chilled to the same temperature as DSW (CSSW) for 87 days. Red sea bream successfully acclimated to DSW but the temperature of DSW seemed too low for growth of red sea bream. To know the effects of DSW acclimation on muscle properties, we compared post-mortem changes of rigor mortis and degradation of ATP-related compounds during storage at 0°C and 10°C, and IMPase activity 30 and 87 days after the start of rearing. Acclimation to DSW for 30 days caused the delay of rigor mortis, especially in fish stored at 10°C. The delay of the rigor mortis was supposed to be caused by the low temperature of DSW. The relationship between the progress of rigor mortis and the degradation of ATP was, however, not clear. Differences in rigor mortis among experimental groups became unclear after rearing for 87 days, with the decrease of the difference of water temperature between SSW and DSW.
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  • Koji Inoue, Katsuji Morioka, Itaru Shioya, Toru Mitsuboshi, Yoshiaki I ...
    1998 Volume 64 Issue 5 Pages 804-807
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    To examine the effect of deep seawater (DSW) acclimation on properties of the fish muscle, we reared red sea bream Pagrus major in DSW, surface seawater (SSW) and chilled surface seawater (CSSW) which was chilled to the same temperature as DSW. Free amino acid (FAA) content, total lipid content, fatty acid (FA) components of lipid, and texture of the ordinary muscle were compared 30 and 87 days after the start of rearing. It was found that acclimation to DSW and CSSW induces an increase of Gly, Lys and His in FAA. The proportion of docosahexaenoic acid (DHA) in FA was stable in fish reared in DSW and CSSW while it decreased in fish reaed in SSW. In addition, an increase of hardness of the muscle after the acclimation to DSW and CSSW was detected by texture analysis. Such changes were not significant after rearing for 30 days and became remarkable after rearing for 87 days. Since such changes in FAA, FA, and texture were observed both in DSW and CSSW groups, they were presumed to be caused mainly by the low temperature of DSW.
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  • Takaho Tajima, Jun Tamori, Nobuyuki Kanzawa, Toru Tamiya, Takahide Tsu ...
    1998 Volume 64 Issue 5 Pages 808-811
    Published: 1998
    Released: June 30, 2008
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    We previously reported that novel metallo proteinases, myosinase I and II, which specifically hydrolyzed a myosin heavy chain were purified from squid mantle muscle.
    In this report, we show the distribution of myosinases in Coleoidea. Spear squid and cuttlefish had myosinase I activity. Japanese common squid had both myosinase I and II activity. In the previous report, we showed that myosinases activity was detected only in extract of Teuthoidea mantle muscle. But in this research, we detected the myosinases activity not only in mantle but also in other tissues other than ovaries from various species of Coleoidea. Each of the livers contained especially high activity.
    This results suggest that myosinases hydrolyze other substrates.
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  • Takao Ojima, Nagako Kawashima, Akira Inoue, Akiko Amauchi, Marie Togas ...
    1998 Volume 64 Issue 5 Pages 812-819
    Published: 1998
    Released: June 30, 2008
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    Primary structure of heavy meromyosin region of walleye pollack Theragra chalcogramma myosin heavy chain was determined by cDNA cloning. By using one PCR product and five cDNA clones isolated from a λgt11-cDNA library for the pollack dorsal muscle, a nucleotide sequence of 3, 923 bp comprising 60 bp of 5'-untranslational region and 3, 863 bp of coding region was determined. The deduced sequence of 1, 287 amino acids showed considerably high homology to the corresponding regions of carp myosin (83%) and chicken and rabbit myosins (both 79%). The sequences of the regions for the putative ATP-binding, actin-binding, and regulatory light chain-binding were well conserved among the pollack, carp, chicken, and rabbit myosins (83-100% homology). On the other hand, relatively low sequence homologies were seen in the essential light chain-binding site (52-78%), junctions between 20-kDa and 50-kDa domains (27-33%) and 25-kDa and 50-kDa domains (53-57%) of subfragment-1.
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  • Hisashi Hashimoto, Yoshiyuki Matsuo, Yoshihiro Yokoyama, Haruhiko Toyo ...
    1998 Volume 64 Issue 5 Pages 820-825
    Published: 1998
    Released: June 30, 2008
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    Effects of osmotic stresses on apoptotic cell death of a fish cell line (Epithelioma Papulosum Cyprini, EPC) were investigated. EPC showed DNA fragmentation, which is a biochemical feature of apoptosis, under hypertonic stress, when exposed to 400-600mOsm/kg media with sodium chloride supplementation. Similar results were obtained upon exposure to 450mOsm/kg medium with sorbitol. DNA fragmentation increased significantly within 3h after exposure to the hypertonic stress. Nuclear condensation, which is a morphological hallmark of apoptosis, was also observed in the culture of EPC exposed to hypertonic stress. The amount of native nucleosomal DNA was evaluated to find whether the whole cell population undergoes apoptosis. As a result, hypertonicity below 500mOsm/kg triggered apoptotic cell death only in a part of the whole cell population, while 600mOsm/kg brought about cell death in a large proportion of the population by necrosis as well as apoptosis. In contrast, hypotonic media (150 and 200mOsm/kg) did not induce DNA fragmentation. DNA fragmentation of EPC induced by hypertonic stress was suppressed in the presence of Zn2+, suggesting that a Zn2+-sus-ceptible endonuclease(s) may be responsible for cleavage of nucleosomal DNA.
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  • Eiji Yamashita, Yutaka Maruyama, Masaaki Katsuyama, Miyuki Tsushima, S ...
    1998 Volume 64 Issue 5 Pages 826-830
    Published: 1998
    Released: June 30, 2008
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    An apocarctenoid, (3R)-galloxanthin, (3R)-10'-apo-β-carotene-3, 10'-diol, (1.1% of total carotenoids) has been isolated and identified from the integuments of wild mature koayu Plecoglossus altivelis. This is the first report of the occurrence of galloxanthin in fish.
    Feeding experiments were carried out on young koayu with β-carotene, canthaxanthin, (3R)-β-cryptoxanthin, (3R, 3'R)-astaxanthin, (3S, 3'S)-astaxanthin, (3R, 3'R)-zeaxanthin, lutein A, andfucoxanthin. In the integuments, canthaxanthin and (3R)-β-cryptoxanthin were directly accumulated, but neither β-carotene nor fucoxanthin were accumulated. Lutein A was metabolized to lutein B. (3R)-Gal-loxanthin was produced by eccentric cleavage from (3R, 3'R)-zeaxanthin which is the principal carotenoid in koayu. (3R, 3'R)-Astaxanthin was reductively metabolized to (3S, 3'S)-zeaxanthin and finally converted to a new apocarotenoid (3S)-galloxanthin.
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  • Shigeharu Kinoshita, Kiyoshi Kikuchi, Hiroshi Yamada, Takeya Hara, Yas ...
    1998 Volume 64 Issue 5 Pages 831-835
    Published: 1998
    Released: June 30, 2008
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    We investigated mRNA expression patterns in the laboratory-reared diatom Chaetoceros compressum under temperature stress conditions. The diatom incubated at 30°C for 15min, showing 43% growth rate in a subsequent culture at 20°C for 2 days, were analyzed by mRNA arbitrarily primed reverse transcription-polymerase chain reaction (RAP RT-PCR) in comparison with control cells incubated at 20°C throughout. The heat stress at 30°C induced expression changes in 7 cDNAs, one of which showed 37% identity to a homologous region of the Bacteroides fragilis glutamine synthetase gene. This stress on the diatom resulted in 2.5-fold increase in its mRNA levels. Our results demonstrated that the gene (s) related to this cDNA is expressed in response to heat stress for the diatom, suggesting its possible applications to monitoring marine environments.
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  • Etsu Nugroho, Motohiro Takagi, Ketut Sugama, Nobuhiko Taniguchi
    1998 Volume 64 Issue 5 Pages 836-837
    Published: 1998
    Released: June 30, 2008
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  • Kou Ikejima, Naoki Mizuno, Hisashi Kurokura, Makoto Shimizu
    1998 Volume 64 Issue 5 Pages 838-839
    Published: 1998
    Released: June 30, 2008
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  • Ryuji Kondo, Manabu Komura, Shingo Hiroishi, Yoshihiko Hata
    1998 Volume 64 Issue 5 Pages 840-841
    Published: 1998
    Released: June 30, 2008
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  • Hideaki Morii, Toru Takita, Tengku Dahril
    1998 Volume 64 Issue 5 Pages 842-843
    Published: 1998
    Released: June 30, 2008
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  • Jiunn-Bin Huang, Tai-Sheng Chiu
    1998 Volume 64 Issue 5 Pages 844-845
    Published: 1998
    Released: June 30, 2008
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  • Saksit Chanthai, Hidekazu Nieda, Masahiro Ogawa, Toru Tamiya, Takahide ...
    1998 Volume 64 Issue 5 Pages 846-847
    Published: 1998
    Released: June 30, 2008
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  • Kunihiko Konno
    1998 Volume 64 Issue 5 Pages 848-849
    Published: 1998
    Released: June 30, 2008
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  • Toshiyuki Suzuki, Makoto Yamasaki, Hiroto Ota
    1998 Volume 64 Issue 5 Pages 850-851
    Published: 1998
    Released: June 30, 2008
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  • Kenji Hayashi
    1998 Volume 64 Issue 5 Pages 852-853
    Published: 1998
    Released: June 30, 2008
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  • Masaru Ishikawa, Yuji Nagashima, Kazuo Shiomi
    1998 Volume 64 Issue 5 Pages 854-855
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
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