Fisheries science
Print ISSN : 0919-9268
Volume 64 , Issue 2
Showing 1-35 articles out of 35 articles from the selected issue
  • Yuzuru Ikeda, Nobuaki Arai, Wataru Sakamoto, Hideaki Kodokoro, Koji Yo ...
    1998 Volume 64 Issue 2 Pages 179-184
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    Trace elements in the statoliths of the Japanese common squid Todarodes pacificus were analyzed with PIXE (Particle Induced X-ray Emission) to investigate the environmental fluctuations that squid encountered in the ocean. To examine the quantitative relationship between the trace elements of T. pacificus statoliths and the vertical temperature profile of squid habitat, the samples were collected from three geographical regions taking account of water temperature distribution in the Sea of Japan: cold water region, intermediate water region and warm water region. Calcium was detected from T. pacificus statoliths as the main component, and other trace elements such as chromium, manganese, iron, copper, zinc and strontium were detected. The Sr concentration was the highest among those trace elements in the statoliths. In contrast, Cr, Mn, Fe, Cu and Zn were contained at relatively low levels in the statoliths. Sr concentration in the statoliths was high in the group of the cold water region, and the intermediate water region, but was low in the group of the warm water region. It was suggested that the Sr concentration of T. pacificus statoliths could be the key to reconstructing the water region of squid habitat which is expressed by the vertical temperature profile.
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  • Keiyu Marumo, Toshiaki Ishii, Yuusuke Ishikawa, Taishi Ueda
    1998 Volume 64 Issue 2 Pages 185-190
    Published: 1998
    Released: June 30, 2008
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    Concentrations were determined for 14 elements in zooplankters, which were collected along the Pacific coast of central Japan (Boso Peninsula) from October 1991 to August 1992. Analyses were conducted by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry on 5 separate species of Copepoda, 2 cladoceran species and other taxonomic groups including fish eggs. Less variable concentrations were noted for most elements (e. g. Ca, P and Sr) among different species or groups, except for cladocerans and fish eggs which had higher concentrations of some major elements (K, Mg and Na). Negative correlations were found between the concentration factors determined and oceanic residence time of elements.
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  • Daiju Oki, Osame Tabeta
    1998 Volume 64 Issue 2 Pages 191-197
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    We examined 1, 377 specimens of the yellow sea bream Dentex tumifrons caught by bull trawl in the East China Sea and landed at Nagasaki Fish Market from March 1993 to May 1994, and obtained information about age, growth, and reproduction. Ages were determined by scale readings. The relationship of fork length to scale radius was significantly different in males and females. Rings on the scales formed twice a year, spring and autumn. Growth equations are given for spring and autumn spawned fish and for males and females. It is inferred that the calculated fork lengths at age in the present study were smaller than those reported 30 years ago from the East China Sea, in other words, the growth rate appears to have slowed. From the monthly changes of GSI, spawning is estimated to occur twice a year, in spring and autumn. Egg diameter distribution and histologieal observations of the ovaries suggest that each fish spawns several times during the spring and the autumn spawning season.
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  • Tianxiang Gao, Seiichi Watanabe
    1998 Volume 64 Issue 2 Pages 198-205
    Published: 1998
    Released: June 30, 2008
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    Horizontal starch gel electrophoresis was used to investigate the genetic stock structure of the Japanese mitten crab Eriocheir japonica. Twenty-two putative enzyme-coding loci were examined from 1072 crabs at 22 localities from Hokkaido to Okinawa in Japan and 69 Chinese mitten crabs E. sinensis. Nine loci (40.9%) were polymorphic, i.e., AAT-1*, AAT-2*, G3PDH*, GPI*, IDHP-1*, IDHP-2*, MDH-1*, MDH-2* and PGDN*. A geographical cline of allelic frequencies was not clearly recognized at all the loci but the alleles *b and *e at the GPI* locus might be a diagnostic character of the Okinawa populations. The average proportion of polymorphic loci and heterozygosity were 0.149 and 0.020, respectively. Nei's genetic distance was 0.0004 (0-0.0013) which was about 1/140 of the Nei's genetic distance between the Japanese mitten crab and the Chinese mitten crab. Gene diversity analysis indicated that only 1.20% of the variation was between samples. These results indicate that the genetic differentiation of the local populations is small.
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  • Toru Kobayashi, Shozo Fushiki, Noriyoshi Sakai, Akihiko Hara, Masafumi ...
    1998 Volume 64 Issue 2 Pages 206-215
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The reproduction of artificially induced triploid rainbow trout was histologically and endocrinologically examined during three consecutive seasons. The gonadosomatic indices of triploid females were much lower (0.02-0.06) than the indices of diploid females. The concentrations of sex steroid hormones, including testosterone, estradiol-17β, and 17α, 20β-dihydroxy-4-pregnen-3-one, were much lower than those of diploid females but had small changes, and changes of gonadotropin (GtH) levels in the serum of triploid females differed from those of diploid females. Oogenesis in the triploid ovary was substantially delayed, and most germ cells ceased to develop at the synaptic stage of the first meiotic division. At three years old, various developmental stages of oocytes were detected in the ovary, such as peri-nucleolus, yolk vesicle, and early yolk globule stage. It seemed that these rare developments of triploid oocytes were related to the small increases of steroid hormone concentrations and rise of GtH level that appeared when fish were two years old and three years old. Nevertheless, even in triploid ovarian oocytes grown to secondary yolk globule stage, the germinal vesicles did not migrate and there was no ovulation. It was confirmed that triploid liver cells possessed the potential to produce vitellogenin. These results suggest that the genital gland of triploid females is undeveloped because the odd number of chromosome sets causes the first maturation division to fail, and the endocrinological abnormality.
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  • Jun-ichiro Hata, Jiro Takeo, Shinya Yamashita
    1998 Volume 64 Issue 2 Pages 216-219
    Published: 1998
    Released: June 30, 2008
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    Mitogenic activity of rainbow trout fibroblast growth factor 2 (rtFGF-2) to RBCF-1 cell line was enhanced approximately 7-fold by the addition of 10ng/ml heparin, but decreased with excess heparin. This means that there is an optimum quantity of the exogenous heparin for the potential rtFGF-2 activity. On the other hand, heparin protected the rtFGF-2 from thermal denaturation and from the trypsin action. The rtFGF-2 was also proteolyzed in RBCF-1-conditioned medium, but not in the presence of heparin. These results suggest that heparin-like polysaccharides could play important roles to mediate and stabilize the activity of FGF-2 in teleost. Furthermore, to culture cells sensitive to rtFGF-2 from various organs of fish in vitro, suitable amounts of heparin-like molecule are essential to uncover potential and stable rtFGF-2 activity.
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  • Haruyuki Morimoto
    1998 Volume 64 Issue 2 Pages 220-227
    Published: 1998
    Released: June 30, 2008
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    The relationship between batch fecundity and egg size in Japanese sardine Sardinops melanostictus in Tosa Bay and off the Kii Channel, southwestern Japan from 1990 to 1993, was examined using females whose yolk volume of oocytes became constant after hydration at the final maturational stage. Positive correlations were recognized between these two among females whose batch fecundities were less than 30, 000 eggs, while negative correlations were recognized among females those of which were more than 30, 000 eggs, even if they were of the same body length or age. From 1990 to 1992, the former females distributed in the coastal area of Tosa Bay with relatively low surface temperature, while the latter females distributed in the offshore area of Tosa Bay or the frontal region of the Kuroshio Current off the Kii Channel with relatively high surface temperature. In 1993, these offshore spawners in the Kuroshio region became almost extinct, simultaneously many females that spawned more than 30, 000 eggs per single spawning were observed in Tosa Bay. These results suggest that the spatial changes of batch fecundity of sardines from 1990 to 1992, which influenced the egg size, resulted in the populationspecific fecundity.
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  • Yuji Okazaki, Hideaki Nakata, Yukio Iwatsuki
    1998 Volume 64 Issue 2 Pages 228-234
    Published: 1998
    Released: June 30, 2008
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    Distributions of fish larvae and their prey were simultaneously observed on February 11 and 12, 1995 in the vicinity of a thermohaline front at the entrance of Ise Bay, Japan. The front was about 0.5km in width, where a marked change in temperature (about 4°C) was detected. Most of the larvae were Japanese sand lance and greenlings fish. The densities of the larvae were appreciably higher inshore and at the front than those outside of the front; few larvae were collected in the offshore. On the other hand, copepod densities were relatively high at the front and lowered toward the offshore and inshore. The number of copepodite copepods in the gut contents of greenlings larvae was significantly larger at the front than that of the larvae collected from the inshore. The difference in the number of nauplii in the gut contents was not significant between the front and the inshore; this was probably because the greenlings larvae mainly fed on copepodite copepods. The thermohaline front possibly functions as a barrier to the larvae transported from Ise Bay, and enhances their food availability by increasing copepod densities at the front surface.
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  • Yutaka Kawakami, Noritaka Mochioka, Akinobu Nakazono
    1998 Volume 64 Issue 2 Pages 235-239
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The immigration period, age at immigration, and hatching dates of 174 glass-eels Anguilla japonica caught in northern Kyushu during 1994 were examined, based upon continuous sampling and counting of the daily increments of the sagittal otoliths.
    Immigration of glass-eels to northern Kyushu occurred from February to July, four months later than on the Pacific coast. Examination of otoliths showed that glass-eels had entered into freshwater at the mouth of rivers at the age of 169±15 days (mean±SD). Hatching dates extended from August 1993 to January 1994 and the mean ages of glass-eels of different hatch months were as follows: August-184, September-166, October-169 and November-168 days. The peak spawning month was September. Otolith microstructure showed three separable phases, i. e., leptocephalus stage, metamorphosing stage and glass-eel in sea water stage. Age at the freshwater mark and duration of the leptocephalus stage of August-hatched eels were significantly older and longer, respectively, than those eels hatched in other months.
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  • Takahito Shikano, Eishi Arai, Yoshihisa Fujio
    1998 Volume 64 Issue 2 Pages 240-244
    Published: 1998
    Released: June 30, 2008
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    Seawater adaptability, osmoregulatory function, and branchial chloride cells were compared between the original strain (S3) and the selected strain for high salinity tolerance (S3-SR3) of the guppy. Survival time in 35 ppt seawater was significantly longer in the S3-SR3 strain than in the S3 strain, indicating the higher salinity tolerance of the S3-SR3 strain. When fish were acclimated to 15 ppt dilute seawater, LD50 (ppt) of the S3 and S3-SR3 strains gradually and significantly increased with increase in the acclimation periods in parallel, and the S3-SR3 strain acquired seawater adaptability earlier than the S3 strain. Blood osmotic pressure after direct transfer to 15 ppt dilute seawater of the S3 strain significantly increased 1 day and 2 days after the transfer while that of the S3-SR3 strain did not significantly increase throughout the experiment. Branchial chloride cells of the S3-SR3 strain increased about 50% in number and about 15% in size in comparison with those of the S3 strain in fresh water. These results suggest that genetic increase in the number and size of branchial chloride cells in the S3-SR3 strain caused the improvements of salinity tolerance, seawater adaptability, and osmoregulatory function.
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  • Takeshi Igarashi, Masato Miyata, Goro Yoshizaki, Ikuo Hirono, Takashi ...
    1998 Volume 64 Issue 2 Pages 245-250
    Published: 1998
    Released: June 30, 2008
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    Five carp β-globin genes, Nos. 1β, 4β, 5β, 6β, and 7β, were found to be linked with their respectively numbered and previously described α-globin genes, Nos. 1α, 4α, 5α, 6α, and 7α, in a head-to-head manner. The structure of all five carp β-globin genes were found to be analogous to those of known vertebrate globin genes, i. e., they possess three exons, two intervening sequences (IVS), a sequence that corresponds to the consensus of a SP1 binding site, a CCAAT box, an ATA box, and a polyA signal. The five β-globin genes each included three open reading frames consisting of 444 base pairs encoding 148 amino acid residues. The deduced amino acid sequences of the five β-globin genes were highly conserved, and were highly homologous with that of the known carp β-globin gene No. 3 (>95.3% similarities). This is the first report of six globin genes from an individual fish that have similar nucleotide sequences.
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  • Yongjun Tian, Makoto Shimizu
    1998 Volume 64 Issue 2 Pages 251-258
    Published: 1998
    Released: June 30, 2008
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    Based on daily growth lines and their growth increments in the chondrophore, hatch dates and growth rates of the cockle Fulvia mutica in Tokyo Bay were estimated, and factors determining the seasonally in growth were investigated.
    The estimated hatch dates ranged throughout the year. However, the frequency distribution of hatch dates of samples indicated that most of the cockles hatched from March to July with a peak during April and May. In particular, hatch dates of a young group with daily growth lines less than 365 (less than 1 year in age) ranged from March to August with a peak during May and June. Accordingly the main spawning season of the cockle was determined as spring in Tokyo Bay. This result is consistent with the estimation done by an alternative method.
    Daily growth rate varied considerably by individual samples and the mean growth rate was high in the late spring, autumn and early winter, and low in the midsummer and winter. The growth rate remained at a low and stable level after maturation. Among factors determining the seasonality in growth, for the cockles less than 1 year in age, water temperature was of major importance, while for adult cockles maturation and spawning may also have some influence.
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  • Moustafa Ali Salem, Yuri Omura
    1998 Volume 64 Issue 2 Pages 259-264
    Published: 1998
    Released: June 30, 2008
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    The development of the inner ear, especially sensory maculae and otoliths, was studied in the ayu Plecoglossus altivelis, using light and electron microscopy. Light microscopy indicated: 1) The auditory vesicle first appears by 3 days after fertilization. The saccular macula overlain by a round otolith appears and possesses apical hairs by 4 days, while the utricular macula appears by 5 days after fertilization. 2) 9 days after fertilization (hatching day), both the saccular and utricular maculae are well differentiated: composed of hair cells and supporting cells, and overlain by saccular and utricular otoliths, respectively. Electron microscopy revealed: 1) By 5 days after fertilization, sensory hair bundles and bud-like microvilli protrude from the apical surface of the saccular and utricular maculae into the endolymphatic lumen. 2) Secretory materials, such as electron dense cytoplasmic extrusions, vesicles containing spherules, and dense granules, seem to occur from the apical surface of sensory epithelium, probably supporting cells, and to contribute to the formation of the otolith and/or otolith increments. 3) By 9 days after fertilization, the saccular otolith possesses an inner incremental layer around the central nucleus and a thick belt of peripheral incremental layer. Consequently, it was suggested that the hearing mechanism in the ayu may be established earlier compared with other fishes.
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  • Tasuku Watanabe, Naoya Kubo, Hiroshi Ohta, Michiko Kono, Kiyoshi Furuk ...
    1998 Volume 64 Issue 2 Pages 265-269
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    We examined the production site of the resident intraperitoneal free cells of red sea bream Pagrus major, histologically and electron microscopically. There were many large round cells in mesenteriolum and the adjacent coelomic space near head kidney. Electron microscopical observation showed that the large round cells observed in the mesenteriolum and the adjacent coelomic space were a few heterophilic granulocytes and abundant large cells with similar morphologies of those observed in the abdominal cavity. In the mesenteriolum and the adjacent coelomic space, there were a few fibroblastic cells with many oval granular or vacuole-like structures, which had morphological similarity to the granules of peritoneal large cells. There were abundant round cells in mesenteries, most of which were heterophilic granulocytes. The 5-bromo-2'-deoxyuridine incorporation experiment revealed that these cells observed in the interstitial tissue were not aged but the young cells within 4 days after cell division. The results obtained in this study suggest that mesenteriolum and the adjacent coelomic space near head kidney are one of the pathways of granulocytes and large cells to abdominal cavity and provides the field of large cell production.
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  • Teruo Azuma, Yasuhiro Chikushi, Yasuo Itazawa
    1998 Volume 64 Issue 2 Pages 270-275
    Published: 1998
    Released: June 30, 2008
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    Adjustments in respiration and blood circulation of a porgy Pagrus major exposed to acute drop of temperature were investigated. Water temperature was lowered from the acclimated level of 21°C to the test level of 16°C at the rate of 0.13°C-min-1, kept at 16°C for 3hours, and returned to 21°C at the same rate. In the period of lowered temperature, oxygen consumption was reduced to 60% of the precooling level. Respiratory frequency, stroke volume of gill ventilation, and minute volume of gill ventilation decreased to 73%, 41%, and 57% of the pre-cooling level. Oxygen utilization at the gills, partial pressure and concentration of oxygen, hematocrit value, hemoglobin concentration of the arterial blood, and oxygen concentration in the mixed venous blood did not show any significant change. Arterial pH elevated. Heart rate decreased, stroke volume of cardiac output increased, and minute volume of cardiac output did not significantly change. Oxygen utilization at the tissues did not change. All the parameters showed the pre-cooling level when water temperature was returned to 21°C. From these results, lowering temperature by 5°C is considered to be an effective and safe way for successful transportation of live fish.
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  • Sadao Kiyohara, Kouji Shintomo, Satoru Yamashita
    1998 Volume 64 Issue 2 Pages 276-281
    Published: 1998
    Released: June 30, 2008
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    In order to reveal whether trigeminal fibers project directly onto the medullary taste center of fish, the fluorescent carbocyanine dye DiI was applied to the stump of the trigeminal nerve root in isolated, fixed brains of 6 species of fish (Halichoerus poecilopterus, Pagrus major, Stephanolepis cirrhifer, Platycephalus indicus, Cyprinus carpio and Carassius auratus). After a diffusion period, the brains were serially sectioned on a vibratome and examined on an Olympus epifluorescence microscope, In each species the entire trigeminal root was clearly labeled and the whole central projections of the trigeminal root were easily traced. The afferent fibers of the trigeminal nerve turn caudally after their entrance to the brain to form the descending root. Through the descending root trigeminal fibers were found to project onto the medullary taste center as well as other trigeminal targets in the medulla and spinal cord in all species of fish examined. The area of the medullary taste center, which receives the trigeminal projections, was found to be a ventromedial portion of the intermediate facial lobe (FL) in Cyprinus carpio and Carassius auratus, and an anterior portion of the longitudinal taste center in the other species examined. This anterior portion corresponds to the FL of the cyprinids. These results suggest that direct projection of trigeminal fibers onto the FL is a general feature in teleosts although the amount of projection varies considerably among species.
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  • Eiichi Nara, Kazuo Miyashita, Toru Ota, Yoshitaka Nadachi
    1998 Volume 64 Issue 2 Pages 282-286
    Published: 1998
    Released: June 30, 2008
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    Comparative studies on fatty acid composition and oxidative stability indicate the advantages of salmon egg phosphatidylcholines (PCs) for liposomal materials with high contents of n-3 polyunsaturated fatty acids and relatively high oxidative stability. The oxidative stability of salmon egg PC liposomes increased by the addition of cholesterol, decetyl phosphate, and stearylamine. The oxidation of salmon egg PC liposomes was also inhibited by chicken egg albumin and α-tocopherol, however, the high concentration of α-tocopherol exhibited a prooxidant activity. When DHA-enriched triacylglycerols (TGs) were encapsulated in liposomes of soybean PC, chicken egg PC, and salmon egg PC, respectively, the highest oxidative stabilities of both TG and PC were shown in salmon egg PC liposomes. This result suggests that salmon egg PC is a potentially useful liposomal material for encapsulation of readily oxidizable fish oils.
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  • Yumiko Azuma, Kunihiko Konno
    1998 Volume 64 Issue 2 Pages 287-290
    Published: 1998
    Released: June 30, 2008
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    The Freeze denaturation mechanism of myofibrils was investigated by comparing with the thermal denaturation. Mg2+-ATPase activity enhancement was brought about in these two denaturation systems, whereas Ca-sensitivity loss was accompanied only in the thermal denaturation. Frozen storage slightly decreased the salt-solubility as well as myosin extractability. The latter change was rather similar to the Ca2+-ATPase inactivation profile. This was in contrast to the case of thermal denaturation, in which myosin extractability as well as solubility dropped very quickly preceding the Ca2+-ATPase inactivation. It was, therefore, concluded that the structural change of myosin caused by freezing is different from that by heating. Myosin rod, a region responsible for the salt solubility of myosin, was suggested to remain undamaged during the frozen storage. It was also found that, when once frozen, myofibrils readily lost their salt solubility upon subsequent heating. It was thus demonstrated that the thermal denaturation process was greatly affected by freezing before heating.
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  • Deng-Fwu Hwang, Liang-Tan Chien, Kwang-Tsao Shao, Sen-Shyong Jeng
    1998 Volume 64 Issue 2 Pages 291-294
    Published: 1998
    Released: June 30, 2008
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    Normal and deformed thornfish Terapon jarbua were collected from waters near the outlet of a nuclear power plant in northern Taiwan from June to September 1994. The levels of vitamin C and heavy metals and the ratio of hydroxyproline/proline in the fish were analyzed. The results indicated that the levels of heavy metals (Zn, Cu, Sn, Pb, and Cd) were not significantly different between normal and deformed fish. But the level of vitamin C and the ratio of hydroxyproline/proline in the deformed fish were lower than those of the normal fish. Thornfish were further separately cultured at 28, 32, and 36°C, and fed a diet without vitamin C-supplement. Deformed fish appeared at 36°C only, but this did not occur when fish were fed a diet with vitamin C-supplement. Therefore, deficiency in vitamin C might be a cause of deformed fish found in waters near the nuclear power plant.
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  • Yasuro Ishizaki, Toshio Takeuchi, Takeshi Watanabe, Misao Arimoto, Ken ...
    1998 Volume 64 Issue 2 Pages 295-299
    Published: 1998
    Released: June 30, 2008
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    The effect of arachidonic acid (AA) on survival and growth of yellowtail Seriola quinqueradiata during Artemia feeding period was investigated through two feeding experiments. Artemia nauplii enriched with oleic acid (OA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and AA were given to 20-day (TL=8.1mm; Expt. I) and 23-day (TL=9.0mm; Expt. II) old larvae for 13 days.
    The fish fed with DHA-enriched Artemia showed the highest growth and best survival rate, whereas those fed AA-enriched Artemia showed the lowest survival rate and poorest growth. In both experiments, the mortality rate of fish fed with AA-enriched Artemia was remarkably high, especially from the 3rd to the 8th day of the rearing. Lipids analysis showed that the neutral lipid content in whole body of the fish fed AA-enriched Artemia was much lower than those in the other three groups.
    This preliminary experiment clearly showed that 4% AA content in Artemia (dry matter basis) has a negative effect on growth performance for the rearing of yellowtail larvae and juveniles.
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  • Kazuo Shiomi, Shuichiro Hayashi, Masaru Ishikawa, Kuniyoshi Shimakura, ...
    1998 Volume 64 Issue 2 Pages 300-304
    Published: 1998
    Released: June 30, 2008
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    The crude extracts from the white muscle of five species of fish (horse mackerel Trachurus japonicus, Pacific mackerel Scomber japonicus, bigeye tuna Thunnus obesus, chum salmon Oncorhynchus keta, and walleye pollack Theragra chalcogramma) were evaluated for allergenicity by enzyme-linked immunosorbent assay (ELISA) using sera from two fish-allergic patients. All the extracts reacted with the IgE antibodies in one patient serum; the highest reaction was given by the horse mackerel extract and the lowest reaction by the bigeye tuna extract. In contrast, the bigeye tuna was the only positive sample as analyzed using another patient serum. Based on ELISAs using the former patient serum, a heat-stable allergen (named Tra j 1) in the horse mackerel was isolated by gel filtration on Sephadex G-75 and reverse-phase HPLC on TSKgel ODS-120T. In SDS-PAGE, Tra j 1 gave a single band corresponding to a molecular weight of 10, 500, regardless of the presence or absence of a reducing agent. The isoelectric point of Tra j 1 was estimated to be 4.3 by IEF-PAGE. Tra j 1 was rich in Ala, followed by Asx and Lys, but lacked Cys (half), His, and Trp. Furthermore, it showed an ability to bind to the monoclonal antibody against carp parvalbumin. From these physicochemical and immunological properties, Tra j 1 was identified as parvalbumin of the horse mackerel.
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  • Izumi Tonegawa, Shigeru Okada, Masahiro Murakami, Katsumi Yamaguchi
    1998 Volume 64 Issue 2 Pages 305-308
    Published: 1998
    Released: June 30, 2008
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    The extracellular and intracellular pigments of the colonial green microalga Botryococcus braunii Kawaguchi-1 were extracted separately, and their contents and compositions in the linear and stationary growth phases were analyzed. The intracellular carotenoids were composed of neoxanthin, loroxanthin, violaxanthin, lutein, α-carotene, and β-carotene. The amounts of chlorophylls and intracellular carotenoids decreased in the stationary phase. The extracellular carotenoids were fairly abundant even in the linear phase and increased still more in the stationary phase. The main component of the extracellular carotenoids was a ketocarotenoid, echinenone. The color change in the stationary phase would mainly be ascribed to the accumulation of echinenone in the intercellular matrix simultaneous with the decrease in the total amounts of intracellular pigment components. Substantial amounts of botryoxanthins and braunixanthins containing a tetramethylsqualene moiety existed unchanged in the intercellular matrix. These carotenoids also contributed to the expression of the reddish color of this alga especially in the linear phase.
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  • Kyung Hee Lee, Mutsuyosi Tsuchimoto, Takahiro Onishi, Zi-hua Wu, Abdul ...
    1998 Volume 64 Issue 2 Pages 309-313
    Published: 1998
    Released: June 30, 2008
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    As a part of the study program to clarify the cause of differences in rigor mortis among other fishes, the temporal changes of muscular contraction in the pillar form of muscle were measured at various storage temperatures in cultured red sea bream and cultured Japanese flounder acclimated at a habitat temperature of 25°C, and the discrepancies in the progress of muscular contraction were examined between both fishes. To examine in detail the temporal changes of muscular contraction at various storage temperatures and then between both fishes, the temporal changes were applied to straight regression lines within the range until reaching a peak of muscular contraction. These regression lines closely matched the actual measurement values. In both fish species, the slope value, the speed of progression of muscular contraction, slowed with the decrease of storage temperature within the range from 25°C to 12°C; on the contrary, within the range under 10°C, it became faster. The progression speed and level of muscular contraction were faster and higher in cultured red sea bream than in cultured Japanese flounder at various storage temperatures. The cold rigor mortis in both fishes, however, appeared equally at storage temperature near 10°C.
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  • Nobuo Seki, Chiaki Nakahara, Hirofumi Takeda, Nobuyuki Maruyama, Hisan ...
    1998 Volume 64 Issue 2 Pages 314-319
    Published: 1998
    Released: June 30, 2008
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    Dimerization of carp myosin heavy chains at the initial stage of endogenous transglutaminase (TGase)-catalyzed cross-linking was investigated under the similar condition to that of setting in fish meat gelation, with 0.5M NaCl and 5mM CaCl2 at pH 7.0 and 25°C.
    Gel filtration chromatography and SDS-PAGE analyses showed that the enzymatic dimerization occurred intramolecularly between the heavy chains, independent of the thermal aggregation and a decrease in Ca-ATPase activity of myosin molecules, but myosin light chains were not cross-linked. The heavy chains were preferentially cross-linked in rod portion than in subfragment-1.
    Monodansylcadaverine (MDC) inhibited completely the dimerization and was incorporated into myosin heavy chains. Chymotryptic digestion of the MDC-labeled myosin revealed that the labeled site was on the rod and heavy meromyosin (HMM) portions, but not on subfragment-1 or light meromyosin portions. Further chymotryptic digestion of MDC-labeled heavy meromyosin produced MDC-la-beled subfragment-2 (S2). All these results indicated the enzymatic dimerization site being located on S2 heavy chain portions of myosin molecule.
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  • Tomoo Sawabe, Chihiro Sawada, Eri Suzuki, Yoshio Ezura
    1998 Volume 64 Issue 2 Pages 320-324
    Published: 1998
    Released: June 30, 2008
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    Intracellular homo-and hetero-polymeric blocks degrading enzyme activity incapable of degrading intact sodium alginate was detected in Alteromonas sp. strain H-4. The enzyme activity for polyM and MG blocks was highest during the late log phase of the bacterium and was not induced by the addition of sodium alginate to the culture medium. The activity for MG random block was as high as that for polyM, but that for polyG block was half and that for sodium alginate was one fifth. At least 4 kinds of enzyme activities, a polyM specific, a MG-polyM specific, and two kinds of polyG specific enzymes, were detected from the crude intracellular fraction, but a trace spot for sodium alginate. Analysis of reaction products using a partially purified preparation of the enzyme indicated that the enzyme generated a saturated diuronate and an unsaturated polyuronide from polyM block. These results suggest that the intracellular enzymes can degrade only oligosaccharides generated from high molecular alginate by the extracellular alginate lyase and may have an important role in the alginate metabolism of the bacterium.
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  • Tetsuichiro Funamoto, Yasuo Mugiya
    1998 Volume 64 Issue 2 Pages 325-328
    Published: 1998
    Released: June 30, 2008
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    The binding of Sr to estradiol-induced proteins (EIP) was studied 7 days after a single injection of 17β-estradiol (E2) into goldfish exposed to Sr-enriched water (5, 10, and 15 mg/l). E2 induced hypercalcemia in a way that was negatively correlated with ambient Sr concentration and hyperstrontemia in a way that was positively correlated with the concentration. Diffusible Ca concentrations in plasma remained unchanged in the estrogenized and control fish, while diffusible Sr concentrations increased with an increase in ambient Sr concentration in both the experimental and control fish. Protein-bound Ca and Sr concentrations in plasma were always higher in the estrogenized fish than in the control fish and their levels decreased and increased, respectively, depending on the ambient Sr concentration. The ratios of EIP-bound Sr to ElP-bound Ca increased with an increase in the Sr concentration. These results suggest that Sr competes with Ca for binding to vitellogenin in estrogenized goldfish.
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  • Eishi Arai, Takahito Shikano, Yoshihisa Fujio
    1998 Volume 64 Issue 2 Pages 329-333
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    The present study examined a factor in seawater which stimulates salinity tolerance and the number and size of branchial chloride cells in the guppy. Salinity tolerance was measured as LD50 24h after transfer to serial concentrations of salinity. LD50 significantly increased from 25.8 ppt to 43.3 ppt 5 days after exposure to 15 ppt dilute seawater. Thus, increases of salinity tolerance were examined on the basis of 5 days' exposure to various solutions which were contained within 15 ppt dilute seawater. LD50 significantly increased in 0.180M NaCl and 0.023M MgCl2 but not in 0.012M Na2SO4, 0.004M CaCl2, or 0.004M KCl. During 5 days' exposure to 0.090M MgCl2, 0.090M Na2SO4, 0.090M CaCl2, or 0.180M KCl which contain the same Na+ or Cl- concentrations as 0.180M NaCl, all guppies died in 0.180M KCl. Using mixtures of NaCl and KCl, it was revealed that more than 0.020M K+ caused death of the guppies. LD50 did not change after exposure to 0.090M Na2SO4 which contains the same Na+ concentration as 0.180M NaCl but significantly increased after exposure to 0.090M MgCl2 and 0.090M CaCl2 which contain the same Cl- concentration as 0.180M NaCl. The number and size of chloride cells did not change in 0.090M Na2SO4 but significantly increased in 0.180M NaCl, 0.090M MgCl2, and 0.090M CaCl2. These results suggested that environmental Cl- stimulates salinity tolerance and the number and size of branchial chloride cells in the guppy.
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  • Osamu Arakawa, Tamao Noguchi, Yoshio Onoue
    1998 Volume 64 Issue 2 Pages 334-337
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
    A mixture of gonyautoxins 2 and 3 (GTX2, 3) in 3% NaCl solution was injected into the right chela of live specimens of the xanthid crab Atergatis floridus which were maintained in an aquarium at 27°C, The specimens were then examined for the contents of paralytic shellfish toxins in the chela and viscera 0.5-48h after injection by high performance liquid chromatography (HPLC) equipped with a fluorometric detector. It was shown that most of the GTX2, 3 administered were transported from the chela to viscera within 12h after injection, where they were converted into saxitoxin (STX). A portion of STX in the viscera seemed to return to the chela thereafter.
    On the other hand, the same species of crab kept in the aquarium was fed on a feed containing a mixture of gonyautoxins 1, 2, 3, and 4 (GTX1-4) once a day for 3-12 days. GTX1-4 were hardly detectable in the chela and viscera of toxin-fed crab specimens, whereas these tissues accumulated significant amounts of neosaxitoxin and STX. The accumulation of toxins during the feeding period was calculated to be 20-30%.
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  • Shigeaki Gorie
    1998 Volume 64 Issue 2 Pages 338-339
    Published: 1998
    Released: June 30, 2008
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  • Masafmi Amano, Makito Kobayashi, Naoto Okumoto, Katsumi Aida
    1998 Volume 64 Issue 2 Pages 340-341
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
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  • Satoru Suzuki, Maki Kamakura, Riichi Kusuda
    1998 Volume 64 Issue 2 Pages 342-343
    Published: 1998
    Released: June 30, 2008
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  • Jusadi Dedi, Toshio Takeuchi, Kazumi Hosoya, Takeshi Watanabe, Tadahis ...
    1998 Volume 64 Issue 2 Pages 344-345
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
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  • Masayori Ninomiya, Jun-ichi Onishi, Takenori Kusumi
    1998 Volume 64 Issue 2 Pages 346-347
    Published: 1998
    Released: June 30, 2008
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  • Toni Ruchimat, Toshiro Masumoto, Yoshiaki Itoh, Sadao Shimeno
    1998 Volume 64 Issue 2 Pages 348-349
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
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  • Hisashi Hashimoto, Kazuharu Takeuchi, Yoshiyuki Matsuo, Yoshihiro Yoko ...
    1998 Volume 64 Issue 2 Pages 350-351
    Published: 1998
    Released: June 30, 2008
    JOURNALS FREE ACCESS
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