Age and growth of brown sole Pleuronectes herzensteini collected from the coastal waters of western Aomori Prefecture from September 1989 to September 1990 were determined from otolith analysis. Observation of the otolith margin verified that annuli (outer margins of the translucent zone) were mainly produced between February and March. This period was associated with the spawning season. Growth of brown sole was expressed by the von Bertalanffy asymptotic growth function as TL_t=255.2(1-exp^{-0.463(t-0.267)}) for males and TL_t=350.2(1-exp_{-0.308(t-0.300)}) for females, where TL_t, is the total length in mm and t is age in years. It was found that the growth rate of brown sole in this study area is very high as compared with the more southern population in the Niigata region.
In the northern Japan Sea, there is a tendency that the growth rate in the northis higher in length at comparable ages. It is possible that the growth of brown sole in the northernJapan Sea is closely related with bottom water temperature.

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Introduction of new functions to a marine bacterium was aimed at by using a plasmid vector. The plasmid pBIN 19, derived from the broad host range plasmid RK 2, was introduced into marine isolated Pseudomonas strain SC 9 by electroporation. Despite the low transformation efficiency of the bacterial conjugation method reported previously, a transformation efficiency of 1.81×10⁴transformants/μg of pBIN 19 was obtained for the strain SC 9 by electroporation. The introduced pBIN 19was not detected in plasmid form in transformed cell. Southern blot hybrids appeared in genomic DNA under 50 kb using crossed field gel electrophoresis, which indicated introduction and recombination of pBIN 19 into genomic DNA of Pseudomonas SC 9.

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The construction of the pot entrance may be reflected in the degree of the change in the individuals in a pot. The efficiency of a small pot for Macrobrachium nipponense was studied. To clarify how the pot entrance design affects the efficiency of a pot, a series of tests were carried out under actual fishing conditions. The prawn's entry and its escape behavior was observed frequently and the length of the individual's stay in a pot was relatively short. The variations in the efficiency could be explained by the differences in the funnel design of h (height of neck)/d (diameter of opening). The apparent efficiency was maximum at h/d=3.1. The results suggest that the interaction between individuals in a pot is controlled by the funnel design.

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DNA fingerprint (DNA-FP) was applied for confirmation and identification of clones induced by the suppression of the first cleavage in ayu, Plecoglossus altivelis. The samples used were 2 homozygous clonal lines, 3 successive homozygous clonal lines and 2 heterozygous clonal lines. We examined suitable enzyme/probe combinations and compared radioisotope (RI) and non-radioisotope (Non-RI) labelled probes to get clear DNA-FP.
The clear DNA fingerprints were obtained by using YNZ 22, 33. 15 and 33.6 probes with Hae III, Msp I and Hinf I restriction enzymes. In these DNA-FPs, the bands were separated distinctly throughout the membrane in both higher and lower molecular weight regions. The DNA-FP bands obtained with the Non-RI labelled 33.15 probes were as intense and clearly separated as those obtained with the RI method. All the fragments were shared among individuals within the same clonal line, but the pattern of bands detected was significantly different between clonal lines.
It was confirmed that DNA-FP is effective for the identification of clonal lines. DNA-FP pattern by Non-RI labelled probe would be suitable for wide applications in studies on inbreeding and identification of individuals and families.

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A feeding experiment was conducted to investigate the effect of combined use of several alternative protein sources for fish meal in diets for fingerling rainbow trout Oncorhynchusmykiss. In the control diet, brown fish meal (BFM) was used as the sole protein source to provide 40% crude protein. In the test diets, 60 or 80% of the BFM protein in the control diet was isonitrogenously replaced by several combinations of soybean meal (SBM), meat meal (MM), malt protein flour (MPF), corn gluten meal (CGM), and dried brewer's yeast (DBY). These diets were fed to the fish with an initial mean weight of 9.4g for 6 weeks at 16°C.
Combinations of SBM and MPF, SBM and CGM, and MM and MPF at the 60% replacement level improved the weight gain, feed efficiency, and protein retention of the fish relative to the replacement of BFM by SBM or MM alone, and there were no significant differences in these values between the combination group and the control group. Combined use of SBM, MM and MPF at the 60% replacement level showed similar growth and feed performances to the above mentioned SBM and MPF, or MM and MPF diets, however, the performances at the 80% replacement level were inferior.Addition of DBY to the 80% replacement level diet improved the weight gain to the same level attained by the control group.
These results suggest that the combined use of two alternative sources such as SBM and MPF, SBM and CGM, and MM and MPF improve rearing performance of fingerling rainbow trout as cornpared with the use of SBM or MM alone, and that the combined use of SBM, MM, MPF, and DBY at a proper ratio can substitute the 80% of BFM protein.

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In this paper, we attempt to develop a reasonable catch forecasting method for skipjack tuna caught in the north-eastern waters of Japan. In developing such a method, it is very important to find the main factors which control the catch fluctuations. The conventional method is based on the data of mean length and mean fatness of the fish harvested just before the fishing season, and the reproductive relationship estimated using the catch history. This approach, however, failed to forecast the catch in the years when the catch was extremely high. In this study, we therefore focused on the relationship between catches in the north-eastern waters of Japan and the following three variables; (1) catch caught in thewaters off Chiba Prefecture, (2) the Kuroshio current pattern, (3) the first date of capture of skipjack tuna in the waters off Chiba Prefecture, and then forecasted the catch using regression analysis.The results showed that the accuracy of forecasting was very high almost every year including years when the catch was very high. It is considered that the method proposed here overcomes the problems of the conventional method.

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Resource utilization by four sympatric, stream-dwelling salmonids, masu salmon Oncorhynchus masou, coho salmon O. kisutch, steelhead trout O. mykiss, and Dolly Varden Salvelinus malma, wasstudied by underwater observations of microhabitat use and foraging behaviour, and dietary analyses, in a third order tributary of the Bolyschaya River on the Kamchatka Peninsula, Russia in summer, 1993. The Oncorhynchus species differed considerably in microhabitat use, with little overlap. Juvenile masu salmon and coho salmon utilized, respectively, areas of swift and moderate current speed, without selectivity for water depth and overhead cover, whereas steelhead trout selectively occupied deeper water with overhead cover, regardless of current velocity. Dolly Varden were more evenly spread across the stream channel, being closely associated with the stream bottom, whereas the other species selected the mid layer portion of the water column. The latter were typical drift foragers, whereas Dolly Varden adopted both drift and benthos foraging. Stomach content composition differed markedly between masu salmon, steelhead trout, and Dolly Varden. The diet of coho salmon, however, overlapped those of masu salmon and Dolly Varden, but not that of steelhead trout. These results indicated that the four Kamchatkan salmonids were segregated along several niche dimensions in summer, which is considered to be one of the important mechanisms allowing coexistence of these species in lotichabitats.

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An inverter for flexible speed adjustment and an electric motor were combined toform a prototype line hauler with a directly connected electric motor and rollerassembly. This line hauler and a conventional line hauler with hydraulic drive system were compared, and the overall efficiency evaluated.
The results show that a high energy saving effect is observed in the motor driven line hauler with inverter control, giving an energy saving of 24% for a line tension of 800 N anda line speed of 0.6m/s, and energy equivalent to external work is consumed in the roller assembly.

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We found abundant peritoneal cells in normal red sea bream Pagrus major. The cells consisted of three cell types: 1) large round cells with a peripherally located small nucleus and pale cytoplasm (large cells), 2) medium-sized cells with a round or oval nucleus and eosinophilic granules in cytoplasm (eo-sinophilic cells), 3) medium-sized cells with a large round or oval nucleus and basophilic cytoplasm(basophilic cells). Electron microscopically, large cells had many large and slightly electron-dense gran-ules, some of which were degranulated. Eosinophilic cells had abundant granules with a definite electron-dense core in the center or periphery of granules. Nuclei of the cells were polymorphic. Only eo-sinophilic cells had peroxidase activity and were stained strongly with Sudan black B, these characters are principal properties of vertebrate neutrophils. As there were neutrophilic or heterophilic granulo-cytes with similar morphology and staining properties to the peritoneal eosinophilic cells in blood smears and head kidney imprint preparations, we classified these eosinophilic cells as neutrophils.Basophilic cells had slender microvilli, micropinocytotic vesicle-like vacuoles, and bundles of microfibrils. Mitosis was often observed, especially in wild fish. These cells tended to adhere to slide glasses and showed phagocytotic activity to Latex beads. These data indicated the cells were residentperitoneal macrophages.

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The gel-forming characteristics at 40°C and 60°C of the unwashed meat and the washed meat from maeso, wanieso, and tokageeso were examined through the year toconfirm the factor responsible for the modori accompanied by the myosin heavy chain (MHC) degradation.
Heating at 40°C: In every species in every season, washing the meat depressed the proceeding of gel-formation, that is, suwari was inhibitedand modori was enhanced. Moreover, myosin heavy chain degradation was promoted by washing meats. Therefore, 40°C MHC-degrading factor was suggested to be a myofibrillar type throughout the year in every season.
Heating at 60°C: Unwashedmeat of each species exhibited modori at 60°C through the year. Washing the meat didnot affect the modori intensity in maeso at all throughout the year, while in wanieso modori was depressed appreciably by the season and in tokageeso it was depressed to some extent throughout the year. The degradation of MHC corresponded to the intensity of modori in each species. The 60°C MHC-degrading factor is a Mf type in maeso, and a Mf type and a sarcoplasmic type in wanieso and tokageeso, although the major type in these two is variable throughout the year.

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The physical properties of salted jellyfish were studied by X-ray fluorescence (XRF), energy dispersive X-ray analysis (EDX), and thermogravimetric analysis (TGA). The jellyfish were cut into two parts (Middle and Edge) and immersed in water for up to 9 days. XRF and EDX analysis results indicated that NaCl was removedfrom the salted jellyfish on immersion, and that no further NaCl was lost after 3h.
Water contents of unheated and heated (60°C), Middle and Edge parts after immersion were analyzed by TGA. For each sample, water content increased to an equilibrium level. For both unheated samples, water restoration took about 1 h, so thedesalting and water restoring times were different. This implied that the mechanism of rehydration involved both displacement of NaCl by H₂O and also swelling. Although the heated samples did shrink, the equilibrium water contents (after water restoration) were very similar to the unheated samples. This indicated thatthe water retaining structure of the salted jellyfish was not damaged under thoseconditions (60°C for 15min).

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We harvested filamentous cyanobacteria from an alkaline hot spring (45-50°C, pH 8.5-9.0) in Kagoshima Prefecture, and identified it as Lyngbya-Phormidium-Plectonema (LPP) group B by morphological characteristics. From the TCA-soluble fraction of the LPP group B, we isolated glycogen with average chain length of 11 glucose units. The glycogen showed a similar iodine absorption spectrum to that ofrabbit liver glycogen. We also recognized the presence of the TCA-insoluble glycogen at about 48% of total glycogen, most of which was bound non-covalently to protein and showed similar iodine absorption spectrum to that of the TCA-soluble glycogen. We also found thermophilic and thermostable α-glucosidase with optimum pH 6.5 in this cyanobacteria.

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Carp Cyprinus carpio were exposed for 20 days to test waters consisting of combinations of four lead concentrations (0, 10, 100, and 1, 000 ppb) and four levels of water hardness (50, 150, 500, and 1000 ppm as CaCO₃), and 5-aminolevulinic acid dehydratase (ALA-D) activities and lead concentrations in the fish blood were measured. ALA-D activities decreased with increasing blood lead concentrations, and the activities were negatively correlated to the log of the blood lead concentrations (γ=-0.93). Blood lead concentrations increased with increasing waterlead concentrations. However, lead accumulation in the blood lowered with increasing water hardness. ALA-D activities in the leadcontaminated fish blood decreased to about 40% of that of the control fish when carp were exposed for 20 days to test water with a water hardness of 50 ppm CaCO₃ and a water lead concentration of 10 ppb (Environmental Water Quality Standards relating to Human Health in Japan). Judging from the inhibitory degree of carp blood ALA-D, the standard value is the concentration that may cause chronic toxicity to carp.

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The involvement of ovine prolactin (oPRL), bovine growth hormone (bGH), and triiodothyronine (T₃) in otolith and scale calcification was examined using hypophysectomized goldfish Carassius auratus. Hypophysectomized fish received three intraperitoneal injections of either oPRL, bGH, or T₃ every other day, and were keptin water containing ⁴⁵Ca during the last 3 days. Otoliths (asterisci) and scaleswere dissected and the rate of calcium incorporation into these tissues was determined. Plasma calcium and sodium concentrations were also measured.
Hypophysectomy resulted in hypocalcemia and hyponatremia, which were corrected by oPRL replacement therapy. T₃ was effective in correcting only the hypocalcemia. Therapy with bGH induced a further reduction in plasma calcium concentrations below the level of the hypophysectomized control. Calcium incorporation into otoliths and scales was also markedly reduced after hypophysectomy. oPRL was ineffective in stopping this reduction. T₃ corrected the reduction in scales, but not in otoliths.Therapy with bGH completely counteracted the reduction in otoliths and scales and even exceeded the respective sham levels. These results suggest that pituitary hormones, particularly GH, are relevant to otolith and scale calcification, possibly via matrix-related sequences.

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A blue carotenoprotein fraction was liberated from the muscular epithelium of the black tiger prawn Penaeus monodon by extraction with a collagenase solution, leaving another carotenoid fraction in the tissue. Carotenoids in both fractions were analyzed and compared between dark gray prawns and blue ones. The main carotenoid in the carotenoprotein was free astaxanthin, of which content showed no significant difference between the two groups. The muscular epithelium after the removal of blue carotenoprotein turned red owing to the remaining carotenoids which were composed largely of astaxanthin esters. The total content of the remaining red carotenoids was about six-fold higher in the dark gray than blue group. Thus the different body color of cultured black tiger prawns is suggested to bedue to the varied composition of the blue carotenoprotein and red carotenoid fractions in the muscular epithelium.

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Transglutaminase (TGase) plays an important role in the formation of set gel andsubsequent final surimi-based products with greater elasticity and water-holdingcapacity from salted surimi paste. In salmon surimi paste, however, the enzyme activity was inhibited even in the presence of a sufficient concentration of Ca²⁺ required for full activation. It was found that water soluble muscle proteins did not inhibit TGase activity, while deproteinized muscle extract markedly inhibited the enzyme activity and depressed TGase-induced cross-linking and gelationof salmon actomyosin.
The deproteinized salmon muscle extract contained a large amount of anserine as a major nitrogen compound. Anserine inhibited TGase activity, but its inhibitoryaction was slightly lower than that of the muscle extract. However, the reduction of TGase-induced cross-linking of myosin heavy chain and gelation of actomyosin by anserine was in the same extent as that by the muscle extract.

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An unknown substance co-eluted with taurine on an amino acid autoanalyzer was found in the aqueous ethanol extract of the oyster Ostrea edulis. The compound wasextracted from 100g of soft parts from 13 specimens, isolated using Dowex 50 (H⁺ form) and Amberlite CG 400 (OH^-form)columns, and crystallized from hot 50% aqueous ethanol. The yield was 16mg as colorless needles. Its chemical and stereochemical structure was determined to be D-cysteamide [(S)-2-amino-3-sulfopropanamide] by FAB mass, ¹H and ¹³C NMR, IR, and CD spectra and elemental analysis.
In order to confirm the assigned structure, L-cysteamide was synthesized from L-cysteine methyl es-ter hydrochloride in a crystalline form. The synthetic compound was identical with a natural one in mobilities on the amino acid autoanalyzerand TLC and in FAB mass, ¹H and ¹³C NMR spectra but showed a reverse Cotton effect in the CD spectrum.

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Common carp Cyprinus carpio were fed at a constant feeding rate for 30 days on isoenergetic diets containing different levels of lipid (9-18%) and protein (44-59%), and activities of several hepatopancreatic enzymes together with serum andbody compositions were determined. With increasing lipid contents and decreasing protein contents in diet, the levels of lipogenic, gluconeogenic, and amino aciddegrading enzymes together with glycogen were decreased in the hepatopancreas, while those of serum free fatty acid and cholesterol, and hepatopancreatic fatwere increased. Therefore, high correlationcoefficients were obtained between dietary lipid contents and these biochemical parameter levels. The results suggestthat dietary supplementation of lipid depresses lipogenesis, glycogen synthesis, gluconeogenesis, and amino acid degradation in the hepatopancreas.

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Concentrations of stable ¹³³Cs in muscles of flathead flounder Hippoglossoides dubius were determined in separate individuals by means of neutron activation analysis, and were found to decrease with increasing size (age), following the relationship C=470L^-1.05 (C, stable Cs concentration in μg/kg wet weight and L, standard length of fish in cm), over the range of 16.0 to 36.0cm standard length. von Bertalnffy growth model for the sample fish was fitted as: L_t=37.55(1-e^{-0.1030(t+1.83)}), (L_t, standard length in cm at age t). Since the specific activity or ₁₃₇Cs: stable Cs ratio was found to be fairly constant(average 1.2×10⁴ Bq/g Cs) over this range, radiocesium ¹³⁷Cs concentrations are expected to vary withfish size according to the relationship given above. In radio-environmental monitoring programs, the size composition of samples may have to be taken into consideration in assessing monitoring data.

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Oral carbohydrate administration tests were performed in tilapia. Either glucoseor starch in gelatin capsules were administrated orally after the tilapia were put on a fast for 24h. Blood was sampled at selected time intervals from 1 to 12h thereafter. The concentration of plasma glucose of tilapia peaked at 3 h after oral ingestion of both carbohydrates. Plasma insulin concentration in tilapiaingested with glucose was higher (p<0.05) at 1h after oral administration than those ingestedwith starch and the control group. Plasma insulin dilution curve of tilapia was parallel to the insulin standard curve of human beings.

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The stability of black marlin and jack mackerel myosins and their fragments to high hydrostatic pressure (100, 200, 300, 400, and 500 MPa) was examined by meansof a solubility test, CD measurement, and changes in fluorescence intensity. The solubility of both myosins decreased with the hydrostatic pressure-treatment above 300 MPa. There was a marked decrease in thesolubility of S-1, especially in the presence of 0.05M KCl, though the solubility of rod did not alter. The results of CD measurements showed a slight decrease in the helical content of myosins and S-1s. From the data of binding of ANS (8-anilino-1-naphthalene sulfonate), it was indicated that by pressure treatment the fluorescence intensities of myosins and S-ls increased rapidly. By the changes of tryptophan fluorescence intensity the pressure-treated S-1s in 0.05M KCl showed rapidly decreasing curves. The pressure-stability of S-1s in 0.05M KCl was very inferior to that of S-1s in 0.6M KCl.

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Two genetically distinct types of collagen, Type SQ-I and SQ-II, were isolated from the mantle muscle of the squid Todarodes pacificus, and their respective components, α1(SQ-I) and α1(SQ-II), were resolved from the two types of collagen by column chromatography. Rabbit antisera against these collagens and α components were prepared and their immunological properties wereexamined by immunoblot analysis. The anti-Type SQ-I collagen serum reacted intensely to the α2(SQ-I) and α2(SQ-II) components but faintly to the α1(SQ-I) and α1(SQ-II) components. The anti-Type SQ-II collagen serum reacted intensely to the α1(SQ-II) componentbut showed little reactivity to the other a components. Although the anti-α1(SQ-I) component serum was rather crossreactive for the α1(SQ-II) component, it showed a high specificity to the α1(SQ-I) component by treatment with 20 or 50 μg of Type SQ-IIcollagen/1μl of serum at 37°C for 48h. On the contrary, theanti-α1(SQ-II) component serum displayed a high specificity to the homologous antigen. These results suggest that the anti-α1(SQ-I) and anti-α1(SQ-II) component sera can be applied to immunohistochemical experiments as antibodies which recognize Type SQ-I and SQ-II collagens, respectively. The distribution of these two molecular species of collagen in the mantle skin and arm muscle was alsoexamined by immunoblot analysis. Type SQ-I and SQ-II collagen fractions from themantle skin and arm muscle reacted to these four antisera in the same way as those prepared from the mantle muscle. These results demonstratethe wide distribution of these two types of collagen not only in the mantle muscle but also in the mantle skin and arm muscle.

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We have isolated cDNA clones encoding skeletal muscle α-actins of carp Cyprinus carpio and goldfish Carassius auratus. The complete nucleotide (nt) sequences ofcDNA clones and their deduced amino acid sequences were determined. The coding region of cDNA clones contained 1131 nt for both carp and goldfish, while their 3' untraslated regions showed polyadenylation signals. When the two cDNA nucleotide sequences were compared in the overlapping 1257 nt corresponding to the coordinate from -36 to 1221, 35 nt substitutions were observed. Among these, 21 substitutions occurred between T and C, while 25 of total 28 nt substitutions in the coding region were located at the third base. Totally 377 amino acids were deduced from the coding region of both carp and goldfish, although it was predicted that the two N-terminal amino acid residues, Met followed by Cys, would be processed after translation as the cases of other α-actins so far reported. Amino acid sequence differences between carp and goldfish mature α-actins were Asp/Glu-3 and Thr/Val-5.

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The present study is concerned with the effect of dietary L-carnitine supplementation on growth and lipid composition of red sea bream fingerlings. Varying dietary levels of L-carnitine (75, 545, 1087, 2088, and 4162mg/kg) were administeredto five groups of fish during a 42 day period. Fish receiving 2088mg/kg L-carnitine in their diet showed the highest increase in growth. Feed efficiency was positively correlated with the growth rate of fish and remarkably improved as the amount of L-carnitine in the diet increased up to 2088mg/kg. Analysis of lipid composition showed that L-carnitine reduces the amount of free fatty acids inliver indicating an increased fatty acid utilization. Specifically it seems thatL-carnitine promotes the utilization of long chain fatty acids (20-22 carbon atoms) judging from their reduced content in livers of fish fed on L-carnitine supplemented diets.

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Spawned eggs of the squid Illex argentinus are assumed to be wrapped up in fragile gels which are largely derived from the mucosubstance of nidamental glands. This mucosubstance is known to contain mucin-type glycoprotein as a main constituent. In this study, the soluble components of mucosubstance were prepared by sequential extraction with deionized water and 0.6M NaCl, pH 7.2. The water-soluble component was poor in amino sugars and exhibited a low viscosity in solution, indicating the virtual absence of mucin. On the other hand, the salt-soluble component was relatively rich in amino sugars and had a high intrinsic viscosity of 10.0 dl/g. Moreover, sedimentation velocity analyses revealed that it comprised only a simple, sharp peak having a molecular weight of about 6.6×10⁶. When treated with 0.4 N NaOH, about 30% of the salt-soluble component was precipitated with 50% ethanol and identified as mucin. From these results, the salt-soluble component of mucosubstance was found to be a mucin complex which presumably exists in the gel structure of egg mass.

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In vitro effects of 17 α-hydroxyprogesterone and 17 α, 20 β-dihydroxy-4-pregnen-3-one (DHP) on germinal vesicle breakdown (GVBD) of oocytes at various developmental stages were examined in artificially matured Japanese eel. Neither 17 α-hydroxyprogesterone nor DHP induced GVBD in oocytes at a tertiary yolk stage ranging from 600-700 μm in diameter. Oocytes at a migratory nucleus stage ranging from 700 to 800 μm in diameter underwent GVBD in response to 17 α-hydroxyprogesterone and DHP at concentrations of 10 and 100 ng/ml. Oocytes over 800 μm in diameter became more sensitive to the steroids. These results suggest that oocytes acquired the ability to respond to the maturation-inducing steroid at the migratory nucleus stage. Also, oocyte diameter and its microscopic features can be utilized as a reliable indicator of the induced maturation and ovulation by the injection of the steroids.

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The aqueous extract of the Caribbean sea anemone Condylactis passiflora was potently lethal to crabs and weakly hemolytic to animal erythrocytes but had no toxicity in mice. Three polypeptide toxins (named Cp I, II, and III) with lethal activity against crabs were isolated byion-exchange chromatography on DEAE-and CM-cellulose, gel filtration on Sephadex G-50, and reverse-phase HPLC on Nucleosil 300-7C₁₈. The minimum lethal doses against crabs were estimated to be 7.3 μg/kg (Cp I), 7.9 μg/kg (Cp II), and 10μ g/kg (Cp III). The amino acid compositions of the three toxins are closely related to each other; they are all rich in Asx, Ser, Gly, and half-Cys and are devoid of Met. In addition, it is noticeable that CpI and II contain an unusual amino acid, hydroxyproline. The complete amino acid sequences of CpI and II were determined. Both toxins have 47 amino acid residues, among which as many as 43 residues including all 6 half-Cys residues are homologous. Comparisonwith the sequences of the known sea anemone toxins reveals that CpI and II are analogous to type 1 long neurotoxins but have some significant changes in their sequences.

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Klebsiella sp. isolated from the water of the Sumida River produced an extracellular polysaccharide named BS-1. A preliminary study on the structure of BS-1 was performed. Methylation analyses suggested that the polysaccharide was a (1, 3)-galactan having a (1, 2)-linked glucuronic acid and a (1, 4)-linked galactose as side chains. Identification of the methylated sugars was confirmed by GC mass spectrometry. The presence of these two branched sugar residues was also confirmed by periodate oxidation and subsequent Smith degradation. ¹H and ¹³C NMR spectroscopy not only supported these structural features but also indicated that two of the component sugar residues were α-linked and the three other residues were β-linked. These results indicate that BS-1 is a new type of (1, 3)-linked galactan which has the tentative structure as follows:
_??_.

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Translocation of blood calcium to otoliths across the saccular epithelium was examined pharmacologically using an isolated preparation of the otolith-containing sacculus from rainbow trout. Mannitol added to the incubation medium virtually did not permeate into endolymph, indicating that intercellular junctions are tight for calcium to diffuse through a paracellular pathway. The addition of lanthanum or gadolinium to the incubation medium led to a marked decrease in the rate of calcium deposition on otoliths. Verapamil and diltiazem had no effect on the deposition, while Reactive blue reduced the rate to 60% of the control. Although the replacement of sodium with choline in the incubation medium did not change the rate of calcium deposition on otoliths, ouabain reduced the rate in a concentrationdependent way. Chlorpromazine was also effective for the reduction. These results suggest that receptor-operated calcium channels facilitate calcium influx into saccular cellsacross the basolateral membrane and that cytosolic calcium is extruded to the otolith across the distalmembrane by the Na⁺- Ca²⁺ exchanger and ATP-dependent calcium pump.

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The effects of cold storage, freezing and thawing on the browning of scallop adductor muscle which occurs during the cooking process, were studied in relation to the contentof glycogen, glucose and sugar phosphates (glucose-6-phosphate, fructose-6-phosphate, and fructose-1, 6-diphosphate) in the muscle. The changes in content of glycogen, glucose and sugar phosphates were not observed in frozen muscle. Frozen muscle did not show browning after cooking at 110°C for 90min asunfrozen muscle immediately after death. During cold storage (5°C) of unfrozen muscle, glycogen slowly decreased, glucose and sugar phosphates gradually increased, and browning of the muscle gradually increased. When frozen muscle was thawed either slowly (in still air at 0°C) or rapidly (in running water at 15°C), decrease in glycogen and substantial increases in glucose and sugar phosphates occurred, and strong browing of the muscle during the cooking process was observed. During cold storage (5°C) of thawed muscle, glycogen and sugar phosphates gradually decreased, whereas glucose considerably increased, and browning of the muscle gradually weakened. The content of glucose-6-phosphate and the degree of browning were closely related (r=0.85).

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A stable form of ascorbic acid, L-ascorbyl-2-phosphate-Mg (APM), was tested to confirm the effect of APM on juvenile shrimp P. vannamei and determine the optimun supplemental level to diet. Shrimp, weighing 1.10±0.15 g, were fed 5 diets containing graded levels of supplemental APM (0, 10, 18, 33, and 66mg/100g diet) for 18 weeks. Shrimp fed the unsupplemented diet showed deficiency symptoms such as high mortality, molting frequency reduced, and blackened lesions under the exoskeleton, on the abdomen, on the carapace, in the gills and in the foregut. These symptomswere similar to the proposed ascorbic acid deficiency symptoms which is named “black death.” The results of the feeding trials indicated that the supplementation of 10mg APM per 100 g diet was sufficient for a better survival and prevention of clinical signs of vitamin C deficiency symptom in P. vannamei.

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