The power of fishing lights has increased in Japanese squid jigging boats due to vessel competition rather than a proper understanding of the physiology and behavior of the target species. The movement of the black pigment in the outer segment of squid retina is related to exposure time and light intensity. Using the retinomotor response as an index of their retinal adaptation to the light, tank experiments and jigging operations were conducted to examine the relationship between fishing light intensity, the jigging layer depth and time of capture of Japanese common squid Todarodes pacificus. The tank experiments revealed that the retinal adaptation is not correlated with exposure time and intensity, because the iris functions to shield their retina from the rapid increase of light level.The results of jigging operations, however, indicated that their retinal adaptation is correlated with their diel vertical migration. It is suggested that, under the powerful lighting boats, the squid find and seize jigs in the low illuminance area in which the squid can adjust their vision reasonably depending on their retinal adaptation state. On basis of these results, the proper use of fishing lights for squid jigging is discussed.

抄録全体を表示

Larvae of the swimming pea crab Tritodynamia horvathi hatched in the laboratory were reared to adult, and were bred successfully. Zoeal larvae were obtained from ovigerous females collected at Yatsushiro Sound, and they were reared on rotifers, Artemia nauplii and artificial diet. Zoeae hatched in April passed through five zoeal stages during 15-22 days, and the duration of the megalopal stage was 5-11 days. First stage crabs reached the fifth crab stage within two months. Ovigerous females first appeared from September 14, 6 days after the first copulation was observed. However, the percentage of ovigerous females over this period was less than 7%. Copulation and ovigerous females were not detected during November to January. After February 8, copulation resumed and ovigerous females appeared again. The percentage of ovigerous females in the latter breeding season reached 78%. When the crabs were swimming in the aquarium, they were constantly moving their maxillipeds in a regular pattern, and fed on Artemia nauplii or powder of pellets. This suggests that the swimming behavior of T. horvathi is not apeculiar behavior restricted to mating as the copulatory swimming recorded in some other pinnotherids, but a behavior for feeding.

抄録全体を表示

Attraction activities of terrestrial vegetables for black abalone Haliotis discus, oriental weatherfish Misgurnus anguillicaudatus, and yellowtail Seriola quinqueradiata were estimated by behavioral experiments in a laboratory test tank aswell as an attraction index a for both abalone and oriental weatherfish, and another attraction index gr for yellowtail. The indexes a and gr were estimated by a method described in previous papers. Most of the vegetables tested (39 breeds from 36 kinds of vegetables) showed, to some extent, attraction activities for these three animals tested. The highest activity was observed in soybean Glycine max for black abalone, cabbage Brassica oleracea var. capitata (Nakawase 2) for weatherfish, and onion Allium cepa for yellowtail. The attraction activities of these vegetables clearly depended on the concentrations used.

抄録全体を表示

The purpose of this paper is to determine the optimal landing in weight of ayu Plecoglossus altivelis in the scoop nets fishery. First, we define a price function of the landing in weight, taking into consideration its variation within a fishing season. Next, we determine a cost function in a short term, which is the variable cost, through interviews with many fishermen at Lake Biwa. Here, the cost does not mean the opportunity cost. Then, we derive an optimal control problem to determine the landing in weight that maximizes the profit (the landing in value terms minus the cost) subject to some constraints, using the discrete maximum principle. A comparison between the optimized and the real fishery shows that the real fishery is more costly than the optimized one and hence, in spite of larger landings in weight, the total profit of the real fishery is less than the optimized one. This means that the scoop nets fishery is competitively operated.

抄録全体を表示

Total amount of pesticide absorbed and accumulation rates of Microcystis aeruginosa (Cyanophyceae), Scenedesmus quadricauda (Chlorophyceae), and Aulacoseira granulata (Bacillariophyceae) exposed to different single and combination concentrations of the agricultural pesticides, CNP (p-nitrophenyl 2, 4, 6-trichlorophenyl ether), MEP [0, 0-dimethyl 0-(3-methyl-4-nitrophenyl) thiophosphate], and ISP [isoprothiolane (C₁₂H₁₈O₄S₂)] were determined. Lipid analysis was carried out to evaluate the penetration of the pesticides into the cell. The highest total amount of pesticide absorbed and accumulation rates of the three microalgae were obtained upon exposure to different concentrations of ISP while their lowest values were obtained for MEP. The total amount of Pesticide absorbed and accumulation rates differ in the three experimental organisms. M. aeruginosa showed the highest values for all pesticides while S. quadricauda showed the lowest values. The accumulation rates of the three microalgae for a specific pesticide were greatly reduced in the presence of other pesticides in the medium. Results of the lipid analysis showed that ISP was detectable in the lipids of the three microalgae indicating that it can penetrate into the cells. CNP showed a greater affinity to the lipids of S. quadricauda and A. granulata not in M. aeruginosa. MEP did not penetrate into the three microalgal cells.

抄録全体を表示

We developed an ultrasonic telemetry technique for investigating the magnetic sense of the ocean migrating adult salmonids and applied it to maturing chum salmon Oncorhynchus keta off the Kuril Islands in the western North Pacific in September 1994. We made artificial magnetic field generators, consisting of an electromagnetic coil and a drive circuit, which periodically disturb the geomagnetic field around their heads. Tracking was carried out under the following three conditions. Condition 1: the coil and drive circuit were attached to the head and back of three salmon, respectively and an ultrasonic transmitter was also inserted into the stomach for tracking. Condition 2: the dummy coil and drive circuit were attached to the head and back of other three salmon, respectively and an ultrasonic transmitter was also inserted into the stomach. Condition 3: only either a transmitter or a transmitter and the dummy drive circuit were attached to the remaining two salmon. We collected information on the horizontal and vertical movements of the fish. Most salmon moved in southerly directions and swam upper 40m. The average ground speeds ranged from 1.11-1.84 fork length/s for magnetically disturbed salmon (condition 1) and 0.96-1.65 fork length/s for the others (conditions 2 and 3). No significant differences with respect to horizontal movement, vertical movement, and/or swimming speed were found between the magnetically disturbed salmon and the others. The attached devices might give no serious damage to the swimming activity of salmon.

抄録全体を表示

Horizontal starch gel electrophoresis was used to analyze muscle tissue for the variation in 11 enzymes at 17 allozymic loci in three proposed species of the genus Scylla: S. serrata, S. tranquebarica, and S. oceanica. Seven loci were polymorphic at the 17 loci, and at three loci, EST^*, LAP-2^*, and SOD^* gene replacement occurred. The average genetic distances between S. serrata and S. tranquebarica, S. tranquebarica and S. oceanica, and S. serrata and S. oceanica were 0.059, 0.126, and 0.187 respectively, with the relationship between S. serrata and S. tranquebarica being relatively similar. The genetic distances between local populations were very small (0-0.003) within the respective species. The gene replacement at the three loci and the genetic distances between species suggest that the genus Scylla includes at least three species.

抄録全体を表示

Five monoclonal antibodies (MAbs) against cell surface antigens of Vibrio anguillarum serotype J-O-1 were developed by a hybridoma technique. Three of the MAbs, VA19-1, VA19-2, and VA19-4, reacted only with serotype J-O-1. The remaining two MAbs, VA07-1 and VA07-2, showed cross-reaction with some other Vibrio species. MAbs VA19-1, VA19-2, and VA19-4 could react with heat treated (100°C for 1h) cells of V. anguillarum J-O-1. This indicated that the antigens recognized by these MAbs were stable molecules such as lipopolysaccharide. As almost all strains of V. anguillarum isolated from diseased ayu Plecoglossus altivelis in freshwater belong to serotype J-O-1, MAbs VA19-1, VA19-2, and VA19-4 are useful for rapid identification and direct detection of V. anguillarum J-O-1 in natural freshwater environments. Furthermore, MAbs VA19-1, VA19-2, and VA19-4 specifically reacted with V. anguillarum serotype O2 among ten Danish serotypes (O1_??_O10) and did notreact with V. ordalii. Thus, these MAbs are also useful for distinction between closely related species, V. anguillarum O2 and V. ordalii.

抄録全体を表示

In situ perfused hearts of carp were used to investigate the roles of the pectoral musculoskeletal framework covering the pericardial cavity, and the pericardium in cardiac performance. Removing the pectoral musculoskeletal framework decreased stroke volume and cardiac output toabout 70% and 67% of the initial condition, respectively, and raised atrial filling pressure from -2.9±0.48 mmH₂O to above ambient levels. Cutting the pericardium, however, caused no further significant changes in cardiac parameters. Thus, the pectoral musculoskeletal framework of carp is a significant component of the atrial filling via the vis-à-fronte mechanism. On the other hand, the ability of the heart to under-take pressure-related work was significantly enhanced by both removing the pectoral musculoskeletal framework and cutting the pericardium. These results show that both the pectoral musculoskeletal framework and the pericardium prevent the cardiac chambers from over-distention and excessive pressure-related work.

抄録全体を表示

To obtain restriction fragment length polymorphism (RFLP) and variable number of tandem repeat (VNTR) markers from the rainbow trout genome, we constructed a genomic cosmid library from the RTG-2 cell line. Cosmid DNAs were prepared from 25 clones and examined to detect DNA polymorphisms. Three conventional RFLPs and 5 VNTR markers were identified. One of the VNTR markers (RVF9301) consisted of repeat units of a minisatellite tandem repeat of 52 bp inlength. In a primary study for cytogenetic mapping, we succeeded in localizing these markers on rainbow trout chromo-somes by fluorescence in situ hybridization. Our results suggest these 8 clones will serve as useful genetic markers for linkage analysis of genetic traits in fisheries science.

抄録全体を表示

β-Globin cDNA was cloned from a total blood cell cDNA library using carp β-globin cDNA as the probe. This clone contained an open reading frame of 441 bp that encodes a polypeptide of 147 amino acids. The deduced amino acid sequence showed high identity with teleostei β-globin. The functionally important residues that are involved in the contacts with the heme or α-globin chain were shown to be highly conserved among all vertebrate β-globin. The structural features and homology analysis indicated that this molecule was an isoform of rainbow trout β-globin IV. Southern blot analysis using Hind III-digested rainbow trout genomic DNA showed multiple bands and restriction fragment length polymorphism was observed. These results suggest that rainbow trout possesses multiple β-globin gene family.

抄録全体を表示

We have developed a high concentration urea containing buffer (TNES-Urea: 6 or 8M urea; 10mM Tris-HCl, pH 7.5; 125mM NaCl; 10mM EDTA; 1% SDS) for DNA extraction by modifying the cell lysis buffer for DNA isolation, and we found this buffer is suitable for long-term preservation of tissue samples from fish at ambient temperatures and for DNA extraction from fish that are rich in cellular endonucleases. Tissue samples from the Japanese flounder Paralichthys olivaceus and Atlantic herring Clupea harengus were preserved for periods ranging from 1 month to 3 years and for the Atlantic herring transported from Sweden to Japan in TNES-Urea buffer at ambient temperature (10-36°C). The total DNA for each fish was extracted from the muscle or liver tissue which had been preserved for periods ranging from 1 month to 3 years. The DNA yield was 0.5-2.6 μg of total DNA/mg tissue. All DNA from preserved tissues was suitable for DNA analyses, e. g. Polymerase Chain Reaction (PCR) technique, Southern blot analysis and Random amplified polymorphic DNA (RAPD) analysis. The TNES-Urea buffer provides a convenient method of tissue preservation and DNA extraction and offers an alternative to previous methods which require protocols that are restrictive in some field settings.

抄録全体を表示

The degrading process of Laminaria japonica thalli by a marine bacterium, Alteromonas sp. strain AR06, was examined by 4, 6'-diamidino-2-phenylindole (DAPI) stain and epifluorescence microscopy. The surfaces of the thalli particles were densely covered with the bacterial cells within 24 hours of contact and for over 15 days thereafter. A portion of the algal cells was completely fragmented to single cells by the bacterium in a few days. Each single cell detritus (SCD) particle initially contained cytoplasmic material or structure, ca. 6 μm in diameter, as a core, but lost it as a result of bacterial decomposition. These observations were confirmed by the time course change of the particle size distribution, which showed the accumulation of one cell-size particles of around 4-10 μm in diameter. The bacterium could grow on the surface of alginate beads, suggesting possible contribution of this material to the bacterial attachment observed on the thalli. The bacterium was identified as Alteromonas espejiana, an alginate decomposer, according to Bergey's manual of systematic bacteriology. The formation of the single cell detritus may help link the primary production by macroalgae and the secondary production of suspension feeders in algal vegetating areas.

抄録全体を表示

In this series of studies on nutritional energetics in carp and rainbow trout, the present study was conducted to determine the energy requirements for maintenance of body weight and activity, and for maximum growth in the latter fish by feeding them a casein diet, a quality experimental fish meal diet (FD), and a commercial diet (CD) at different feeding levels.
When the fish received the casein diet, the digestible energy (DE) requirements for maintenance of body weight and activity were 26.8, 23.0, and 20.9 kcal/kg body weight/day, and the feeding rates to satisfy these requirements were 0.63, 0.55, and 0.49% of body weight/day in fishof 1.4, 9.1, and 73.8g initial body weight, respectively. The DE requirements of those for maximum growth were 90-100, 80-90, and 60-70 kcal/kg body weight/day, and the corresponding feeding rates were 2.1-2.4, 1.9-2.2, and 1.4-1.6% of body weight/day. These energy requirements slightly decreased with increase of fish body weight, being comparatively lower in rainbow trout than those in mammals.
The DE requirements of fish weighing 23.7g fed FD and CD for maintenance of body weight and activity were 16.0 and 12.6 kcal/kg body weight/day, being 0.38 and 0.40% of body weight/day respectively based on feeding rates, indicating little difference between the two diets. In this experiment, dietary energy budgets were also determined.

抄録全体を表示

Dietary energy budgeting in carp was studied based on the energy requirements for maintenance of body weight and activity, and for maximum growth. Budgeting was determined by analyzing the whole body composition of carp and measuring the digestible and metabolizable energy values (DE and ME) of diets. Fish having a mean initial weight of 243.2 and 5.6g were fed an experimental casein diet, and those of 3.9g were fed a practical type of fish meal diet for 14 or 19 days, respectively.
The energy partitionings of these diets based on gross energy (GE) intake (100%)at the level required for maximum growth were: 16.7-29.9% lost as fecal energy, 1.5-2.0% as non-fecal energy, 31.9-38.9% as heat increment, and 36.7-43.2% as net energy (12.6-15.5% as net energy for maintenance and activity and 24.1-27.7% as productive energy). The proportion of fecal energy value was relatively high and was greatly influenced by the quality of the diet, and the heat increment of feeding was found to occupy a large portion of the energy budgets in fish.
The non-fecal energy loss increased proportionally to the DE intake. The non-fecal energy/DE rate was inversely related to the DE intake in fish receiving DE less than the maintenance requirement of fish body, but above this DE intake, the proportion remained constant.

抄録全体を表示

Plasma IgM levels were monitored bimonthly for three years in individual male and female goldfish reared under natural conditions, with special reference to water temperature and seasonal reproductive cycle. Sexual maturation of the experimental fish occurred normallyin the spring of each year as judged by rises in plasma levels of gonadal steroids. Plasma IgM levels showed clear seasonal change, both in males and females: values became elevated during the period between spring and summer, and declined from autumn to winter. These changes are related, at least in part, to gonadal maturation in spring, since plasma IgM increased concurrently with the rise of steroid hormones, i.e., estradiol-17β and testosterone in females, and 11-ketotestosterone and testosterone in males. IgM levels also showed positive correlations with water temperature. An artificial increase in water temperature, from 5°C to 15°C or 25°C within one day, was seen to induce an acute rise in plasma IgM. These results suggest that the seasonal changes in plasma IgM levels in goldfish are related to both gonadal maturation and water temperature.

抄録全体を表示

Two experiments were conducted to decide the requirement of larval striped jack Pseudocaranx dentex for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by feeding Artemia nauplii containing different levels of EPA and/or DHA for 11 or 12 days. Fish fed oleic acid (OA) enriched Artemia containing a low amount of n-3 highly unsaturated fatty acids (n-3HUFA, mainly EPA and DHA) showed low growth and survival rate, and poor vitality (survival rate at activity test). Elevation of DHA levels in the nauplii improved survival, growth, and vitality. However poor vitality was observed even though fish fed EPA enriched Artemia. Fatty acid compositions of polar lipid in fish body clearly reflected the composition of nauplii. In healthy fish with strong vitality, the ratio of 18:1/22:6 n-3 in body polar lipids remained below 1. This ratio could be an appropriate index for EFA status of larval striped jack.
The requirement of larval striped jack for DHA during the Artemia feeding periodis estimated to be 1.6-2.2% in Artemia. (dry basis) based on larval vitality. On the other hand, fish fed EPA enriched Artemia containing more than 3.1% EPA does not improve neither vitality nor survival.

抄録全体を表示

The changes in the extractability of the sarcoplasmic proteins from the ordinarymuscle of sardine during cold-storage were determined. The protein extractability from sardine decreased by 21% after three-day storage. SDS-gel electrophoresis showed that 36 kDa component from sardine muscle decreased by 61% during cold-storage. The 36 kDa component in the fresh muscle of sardine was purified and identified electrophoretically as glyceraldehyde 3-phosphate dehydrogenase. The sardine and yellowtail enzymes showed the highest activity at around pH 8.2, and were stable at pH 6-9. The heating temperature and time required for half inactivation was 47°C and 15min, respectively. Km values were 1.03mM for sardine and 1.56mM for yellowtail enzymes. On the other hand, the activity of sardine enzyme gradually decreased during cold-storage, whereas that of yellowtail enzyme rather increased up to three-day storage. This difference of the stability at 4°C coincided with the changes in the extractability of 36 kDa component detected in SDS-gel electrophoretic patterns.

抄録全体を表示

The Warner-Bratzler shear test (WB) with a modified shear head and the punch test (PT) using a rheometer equipped with a cylindrical or a spherical plunger were carried out toassess the textural change in fish meat during drying. These mechanical tests were evaluated by comparing them with a sen-sory analysis of the texture. Fresh atoka mackerel muscle as the testing sample was soaked in 1.0M NaCl (pH 7.0) at 13h, and dried at 15°C and 65% in relative humidity for 0-16h.
The shear force and the shear energy of WB have the highest correlation coefficient among the sen-sory textural scores of hardness and firmness. WB faithfully reflected the change in texture of fish meat during drying. On the contrary, PT was insufficient to detect the change in the texture of dried fish meat. The authors concluded that WB with a modified shear head is eminently suitable for measuring the textural change of fish meat during drying.

抄録全体を表示

Two preliminary rearing experiments were conducted to investigate the effects oforal doses of tryp-tophan on fish maturation. Young ayu born in Lake Biwa were used as the experimental fish. In 1991, the experiment was started one month before the usual spawning season using ayu with gonadosomatic index (GSI) of 8.0% in male and 9.0% of female, but in 1992 entirely immature ayu with GSI below than 0.1% in both sexes were used. They were fed three different test diets: i.e., 0.1% tryptophan (TRP), 0.1% p-chlorophenylalanine (PCPA; depleter of serotonin) dietor control. In the group fed the diet containing TRP, the peak of serum testosterone level and timing of spermiation were advanced in males and the final maturation for females was accelerated. Whereas, in ayu fed the diet with PCPA, suppression of serum testosterone levels and the delay in the timing of spermiation were noted in males, and in females lowering of serum estradiol-17β and the delay in the final maturation were observed. Thus, it is estimated that dietary TRP is involved in the maturation, being intermediated by serotonin. Moreover, these findings indicate the possibility that fish maturation can be controlled by not only injection or implanting of sexual hormones but also by oral administrationof TRP, one of essential amino acid in fish.

抄録全体を表示

A feeding experiment was conducted to evaluate the nutritional value of malt protein flour (MPF) in diets for fingerling carp Cyprinus carpio. In the control diet, white fish meal (WFM) was used as the sole protein source to provide approximately 35% crude protein. In the test diets, the WFM protein in the control diet was isonitrogenously replaced by; (1) MPF at the 20, 40, and 60% levels; (2) a combination of MPF and defatted soybean meal (SBM) at the 40 and 60% levels; (3) MPF supplemented with crystalline essential amino acids (EAA) at the 60% level; and (4) extruded MPF at the 60% level. These diets were fed to satiation to fingerling carp with an initial mean weight of 5.5g for 6 weeks at 26°C.
The fish fed the diets with the 20 and 40% MPF substitution levels, and the 60% MPF level supplemented with EAA, showed good growth, feed efficiency, and retention of dietary protein, and the values of these parameters were not significantly different from those of the control group. Moreover, the weight gains of the fish fed the diets containing both MPF and SBM at the 40and 60% replacement levels were significantly higher than that of the control group.
These findings suggest that the use of MPF in combination with SBM is more effective as a substitution of fish meal in fingerling carp diets than is either MPF alone or MPF supplemented with crystalline EAA.

抄録全体を表示

This study aims to clarify the role of brine which was used for the production of fermented sardine Etrumeus micropus with rice-bran (FSR). Fermented sardine in brine (FSB) was experimentally prepared by soaking salted sardine in brine. Most of the nitrogenous components in FSB were higher than those of FSR, while microbial counts of FSB were lower than those of FSR. The content of histamine and tyramine in FSB during the fermentation was higher than that of FSR. During the fermentation alkaline protease activity in FSB was higher than that of FSR. The crude enzyme prepared from brine showed a significantly higher alkaline protease activity. Sardine homogenates were enzymatically hydrolyzed with the addition of various crude enzymes (brine, koji, and rice-bran), and the amino-N (nitrogen) contents were determined. Amino-N content of sardine homogenate with antibiotics was also determined. Amino-N content of each hydrolysate increased after incubation. The degree of enzymatic hydrolysis by brine was higher than those by koji and rice-bran; the degree of enzymatic hydrolysis with antibiotics was almost the same as that without the enzymes and antibiotics. These results showed that brine might play an important role in the protein decomposition of FSR during its fermentation.

抄録全体を表示

Influence of destruction of spinal cord on the post-mortem rigor and muscular ATP consumption was examined in yellowtail, red sea bream, and plaice. In case of yellowtail andred sea bream, the sample whose spinal cord was destroyed (tested sample) showed 6-12 hours delay in reaching full-rigor compared with the control sample. On the other hand, in case of plaice, the tested sample attained full-rigor faster than the control, and the control sample did not reach to full-rigor during 24h storage. Rate of ATP consumption was slower in the tested than the control in yellowtail and red sea bream. In case of plaice, the ATP content was almost the same in both of the tested and the control, and was much in the control for 15-24h storage. Then, it was concluded that destruction of the spinal cord delayed ATP consumption and process of post-mortem rigor except for the case of plaice, and such a specialty of plaice would be caused by the inferiority of autonomic nerve development.

抄録全体を表示

The relation between glycolysis proceeding in scallop adductor muscle during cooking and browning of cooked muscle was studied. G6P increased rapidly at the beginning of cooking and its maximal accumulation occurred at 45°C followed by F6P and FDP, but their accumulation was low compared with that of G6P. Glucose increased slowly during cooking. These substances disappeared after cooking at 110°C for 90min except for glucose. Glycogen decreased at the early stage of cooking and there-after showed a very slow decrease. More than 80% of glycogen still remained evenafter cooking at 110°C for 90min. NAD began to decrease after the muscle temperature reached 60°C, and disappeared after cooking at 110°C for 90min. ATP decreased rapidly at the early stage of cooking and AMP accumulated. Octopine, which is one of the end products of glycolysis in scallop adductor muscle, increased in accordance with decrease of ATP. Glycolysis proceeded very slowly in scallop adductor muscle compared with muscles of fishes. Consequently, sugar phosphates were apt to accumulate especially when scallop adductor muscles were stored at low temperatures or frozen and thawed, and thus the browning of cooked muscle occurred.

抄録全体を表示

A new type of water-in-oil-in-water (W/O/W) emulsion using lipophilized gelatin (LG) and cottonseed oil was developed for the administration of salmon gonadotropin (sGtH) to induce ovarian maturation in the Japanese eel. Hormone-releasing properties of the LG emulsion were compared with a W/O type emulsion prepared with Freund's incomplete adjuvant (FIA) and saline solution in in vitro and in vivo experiments. These results indicated that the LG emulsion had hormone-releasing properties different from those of the saline solution and the FIA emulsion. Cultured immature female Japanese eel (BW, 566 to 1017g) received a weekly intramuscular injection (total of 10 injections) of the LG emulsion, the FIA emulsion or the saline solution, each of which contained sGtH. In the group treated with LG emulsion containing sGtH, all fish matured showing small individual variations in GSI and percent increases in body weight. Although the FIA emulsion was also effective in inducing ovarian maturation, it is possible that ovarian maturation was inhibited by antibodies produced against sGtH. Administration of sGtH in saline solution required a longer period of time for the completion of ovarian maturation. Therefore, it appeared that the LG emulsion containing sGtH was more effective than other preparations in inducing ovarian maturation in eel.

抄録全体を表示

The changes in content of ATP and its related compounds, free amino acids, organic acids, and betaines were investigated in the adductor muscle of noble scallop during storage at 0°C and 5°C.
ATP level immediately after death was 2.6 μmol/g and accounted for 50% of total ATP and its related compounds, but decreased rapidly during the first day of storage. Adenosine (AdR) was detected immediately after death, while IMP, xanthine, and uric acid were detected as the storage period was prolonged. Therefore, it is thought that AMP degraded to inosine via AdR. Hypoxanthine (Hx) concentration and Hx ratio were most suitable for freshness indices of noble scallop. Total amounts of free amino acids immediately after death were 3645mg/100g and increased up to the stage of initial decomposition. Taurine, glycine, and arginine were major amino acids and accounted for 85% of total free amino acids. Aspartic acid, glutamic acid, and alanine were also detected in fairly high amounts. Succinic acid and glycine betaine were detected at 45mg/100g and 877mg/100g immediately after death.

抄録全体を表示

The changes in content of ATP and its related compounds, and free amino acids were examined in the muscle of Japanese spiny lobster Panulirus japonicus during storage at 0, 5, and 20°C in relation to freshness and decomposition.
The level of ATP immediately after death was 8.6 μmol/g and decreased during storage. AMP increased slowly and accumulated. IMP, inosine and hypoxanthine, which were not detected immediately after death, increased during storage. K values ranged from 20 to 25% at the stage of initial decomposition. Main free amino acids were taurine, glutamic acid, proline, glycine and arginine. Sweet and “umami” tasting active amino acids were abundant in the muscle of Japanese spiny lobster. Alanine increased during storage and reached 165 to 181mg/100g at the stage of initial decomposition. Ornithine increased gradually at the acceptable stage and was produced remarkably at the stage of initial decomposition. On the contrary, degradation of arginine was observed. It was concluded that the K value and ornithine were useful as potential indices for freshness and decomposition of Japanese spiny lobster.

抄録全体を表示

A tissue culture bioassay, using the mouse neuroblastoma cell line (Neuro2A), was improved to provide a simple and sensitive bioassay for TTX. The tetrazolium salt, 3-(4, 5-dimethy1-2-thiazoly1)-2, 5-dipheny1-2H tetrazolium bromide (MTT) was applied to replace the time-consuming and incomplete procedure of the original method with automatic measurement, using a microplate reader. TTX was used as a standard and an S-shaped dose-response curve was obtained. In additionto the relative ease of use and objectivity, sensitivity was found to be several times higher than the original (half-maximal inhibition was 12.9 nM TTX). The applicability of this method for detection of TTX produced by bacteria was investigated. Extracts prepared from E. coli cells were amended with a known concentration of TTX and used to determine the effect of this addition to the sample. Although the highly concentrated extract showed cytotoxicity, the effect was reduced when the extract was diluted or purified appropriately. The tetrazolium-based tissue culture bioassay described here may be useful for monitoring or screening for sodium channel blockers (SCB).

抄録全体を表示