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Teisuke Miura, Susumu Shimizu, Sakuzou Nishiyama, Osamu Sato
1986 Volume 52 Issue 7 Pages
1107-1113
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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This study investigates the following problems. The first problem is to describe a model of a set-net as a fish/gear-space system. The second problem is to develop a methodfor derivin gprobable swimming paths, and the third is to evaluate the probable swimming paths.
Research was carried out in a water tank using Yamame
Onchorhynchus masou ahd Ugui
Tribolodon hakonensis. This was a relatively easy means for obtaining data on the ecology of fish and long observation records of fish behavior.
Fish behavior can be termed as an
m-th order Markov process. Therefore, the fish/gear-space system was described as an
m-th order Markov source.
The probable swimming paths were derived from the joint probability of 3 sequential zones (mesh zones)in this study because fish swimming through 3 or more zones appeared to have a chosen path, or direction, in mind. Those were evaluated by using the entropy as defined by the author.
In conclusion, it appears that the above model, the method for deriving probable swimmingpaths and the evaluating method are applicable for investigating fish behavior in relation to any given fish/gear-space system.
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Ichiro Aoki
1986 Volume 52 Issue 7 Pages
1115-1119
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The movement of a fish school with individual differences between members was simulated on a computer. The simulation showed that relatively simple but realistic changes to the be-haviour of one individual in a school can lead to position preferences within a school or leading tendency. The greater approach distance and the weaker directivity of approach movement allowed the individual to be more frequently in the leading position in the simulated school. The entire school moved under influence of the character of the individual in the leading position. The lack of parallel orientation movement increased occurrence in the rear position. The move-ment independent of others resulted in preferences for the foremost and the rearmost position. It was concluded that the approach distance had the most important effect on leading in the schoohl.
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Hiroshi Kitani
1986 Volume 52 Issue 7 Pages
1121-1130
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Artificially matured females of the blue shrimp
Penaeus stylirostris STIMPSON were induced to spawn in the laboratory. The larval development was studied and compared with earlier studies on this species and with that of the brown shrimp
P. californiensis which is similarly dis-tributed in the Gulf of California. Comparison with earlier descriptions of this species reveals differences in morphological characters and in the number of moulting times during the naupliar stages, Comparison with the brown shrimp reveals the close similarities in the larval develop-ment of both species. The larvae of
P. stylirostris reach the first postlarva passing through 6 naupliar, 3 protozoeal and 3 mysis stages as in the brown shrimp.
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Hiroshi Kitani
1986 Volume 52 Issue 7 Pages
1131-1139
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Small samples of gavid shrimp with spermatophore of the white shrimp,
P. vannamei BooNE, were fished by small trawl net on the Pacific coast of Mexico, and induced spawning in the labora-tory. Hatched nauplii were separated into glass beakers, and the larval devolopment was studied and compared with other
Penaeus shrimps such as the brown shrimp and the blue shrimp, which are distributed. in the same Pacific coastal waters. The result reveals very close similarities in morphological characters among thcse
Penaeus shrimps. Meanwhile the growth of larvac was measured continuously, and the moulting times of naupliar stages were examined from a statistical viewpoint.
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D. K. Sakai, Mitsuhiro Nagata, Toshinori Iwami, Nobuhisa Koide, Yoshih ...
1986 Volume 52 Issue 7 Pages
1141-1147
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The control of a naturally-occurring outbreak of bacterial kidney disease (BKD)in masu salmon
Oncorhynchus nasou was attempted by vitamin enrichment and by administration of ery-thromycin, using about twenty thousand hatchery-reared fish. Vitamin was ineffective in the control of BKD, since no difference in the mortalities between fish populations fed 40 days with pellet food supplemented with vitamins (A, D, E, B group, C,
etc.) and fed with normal pellet food. The large alleviation in the mortality was recorded in about five thousand fish receiving an intra-peritoneal injection with erythromycin at a dose of 10mg per kg. Also, the incidence of BKD infection was markedly reduced in dissected fish samples. The reduction rates of the mortality and incidence were 1:4.5 and 1:4.6 in the duration of 20 days after the injection, respectively, compared with those of non-injected fish. Erythromycin conferred no influence (or damage) on the subsequent stages of eyed eggs and alevins from the injected fish. Thus, chemotherapy with erythromycin was considerably promising to control BKD infections in hatchery-reared masu salmon.
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Masahiro Ueno
1986 Volume 52 Issue 7 Pages
1149-1152
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Six series of ten repeated net hauls were made to examine the variation in catches of eggs and pre-larvae among the repeated hauls. The obtained results show that catches of eggs and pre-larvae of
Engraulis japonicus were slightly over-dispersed or randomly distributed.
A poisson mixture model is applied to explain these results. Suppose plankton organisms of some definite types, distributed at random with a mean
M. Let the mean
M be variable and set
Q(M)dM be probability that
M lies between
M and
M+
dM. Then the probability of catching n organisms is
P(n)=∫
∞0Q(M)e
-MM
n/n!dM.
Consequently, we can obtain following relation between the variance σn2 and mean μn of catch n;
σn
2=μn+μn
2(σM/μM)
2where σM
2 and μM are the variance and mean of
M respectively. This relation is equivalentto the one of the variance to the mean in a negative binomial model(NBM). But NBM is a special case that
Q(M)is Gamma distribution in this model.
Apparently, when σM≠0, then σn
2>μn. But there is no reason why aggregation always occurred because variation of
M is caused from many sources, for example, aggregation, prey-predator relation, transport by current, etc. Additional researches should be directed to-ward the causal factors inducing variation of
M.
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Makito Kobayashi, Katsumi Aida, Isao Hanyu
1986 Volume 52 Issue 7 Pages
1153-1158
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Annual changes in the plasma levels of gonadotropin (GtH) and steroid hormones were studied in goldfish. Plasma GtH levels in both sexes were low during winter, and rapidly in-creased in the spawning season in spring. Although gonadosomatic indices (GSI) descresed after the spawaing period, plasma GtH continued to increase, keeping high levels during summer, and declined in autumn. Changes in the plasma levels of steroid hormones were highly correlated with those of GSL Plasma levels of estradiol-17β (E
2) and testosterone in the female were low during winter, and increased rapidly in early spring prior to the GtH increase, then elevated levels were maintained during the spawning period. E
2 and testosterone levels decreased after the spawning season, and testosterone showed an increase in autumn. Changes in testosterone and 11-ketotestosterone levels in male were parallel and similar to those of E
2 and testosterone in female, but increases of these steroids in autumn were more prominent than those in the female.
There is little correlation between plasma levels of GtH and steroid hormones, and changes in the plasma GtH levels seem to be more related to the seasonal change of the water tempera-ture.
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Athiê J. G. Santos, Kiyoshi Furukawa, Makito Kobayashi, Koji Ban ...
1986 Volume 52 Issue 7 Pages
1159-1165
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Plasma gonadotropin (GtH) and steroid hormone levels were monitored during ovulation in the common carp
Cyprinus carpio. Nine out of 14 females ovulated after the water temperature was increased from 16 to 24°C. In the ovulated females, plasma GtH showed acute synchronous elevations in the afternoon around 1500 hours, peaked at midnight, and returned to the basal levels in the morning. Ovulationw as observed at midnight and early morning. Plasma 17α-hydroxy-progesterone and 17α, 20β-dihydroxy-4-pregnen-3-one fluctuated in phase with GtH. Only small changes were observed in the plasma E
2 levels during ovulation. In most of the ovulated fish, testosterone distinctly increased with the commencement of temperature elevation and remained at high levels during the GtH surge, whereas in other ovulated fish only acute changes following the GtH surge were observed. In the unovulated females, large peaks of plasma GtH and steroid hormones were not observed. In some females, however, small rhythmical or irregular changes in GtH and/or steroid hormone levels were observed.
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Athiê J. G. Santos, Kiyoshi Furukawa, Koji Bando, Katsumi Aida, ...
1986 Volume 52 Issue 7 Pages
1167-1172
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Four experiments were conducted to clarify the effects of photoperiod on the onset time of the preovulatory GtH surge in the female carp
Cyprinus carpio. After acclimation together with males under photoperiods of 12L-12D (Group A, lights-on 0600-1800 hours; Group B, 1800-0600 hours) in Experiment 1, 18L-6D (Group C, lights-on 0000-1800 hours; Group D, 0600-2400 hours) in Experiment 2, and 16L-8D (lights-on; 1600-0800 hours) in Experiments 3 (Group E and F) and 4 (Group G and H), water temperature was raised from 16 to 24°C beginning at 1730 hours to induce ovulation and spawning.
In Experiments 1 and 2, a preovulatory GtH surge initiated in the latter part of the light-phase in each photoperiod group after the water temperature was increased irrespective of the starting time of temperature elevation, and ovulation was observed mainly during the dark-phase. In Experiment 3, the light-phase period was changed in Group F from 1600-0800 to 0400-2000 hours after increasing the temperature so that the dark-phase was abruptly inserted after a 4-h light-phase. This change resulted in a delay of the preovulatory GtH surge. In Experiment 4, the GtH surge began at the same clock time as in Experiments 1 and 2 corresponding to the latter part of the light-phase of the acclimation photoperiod even though the photoperiod was changed to 24L and 24D in Group G and H, respectively, after increasing water temperature.
These results indicate that female carp have a reproductive circadian rhythm and the onset time of the preovulatory GtH surge is determined by a photoperiodic cue.
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Takashi Aoki, Akira Akashi, Tetsumi Sakaguchi
1986 Volume 52 Issue 7 Pages
1173-1179
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The properties and DNA structure of thirteen transferable R plasmids detected in
Edwardsiella tarda strains collected in various eel culture ponds were compared. Two R plasmids, encoded for resistance to chloramphenicol (CM), tetracycline (TC) and sulfonamide (SA), inhibited DNA phage growth whereas the remaining R plasmids did not. The restriction and modification systems of these R plasmids were different from those of R plasmids previously reported.
1-3) The diges-tion patterns of R plasmid DNAs with
HindIII could be divided into four groups. Common sequences were observed in PstI digestions of R plasmids carrying resistance to TC and SA, or CM, TC, and SA. pJA6018 DNA encoded with resistance to TC and SA used as a probe hy-bridized strongly to R plasmids containing the same resistance markers and partially hybridized to R plasmids with resistance to CM, TC, and SA.
Aeromonas hydrophila R plasmid encoded with resistance to TC and SA hybridized to the E. tarda R plasmid encoded with the same re-sistance marker. These results suggest that an R plasmid with the identical DNA structure every-where is widely distributed in eel culture ponds in various areas.
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Tsutomu Kobata
1986 Volume 52 Issue 7 Pages
1181-1187
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The abundance of adult yellowtail
Seriola quinqueradiata TEMMINCK et SCHLEGEL in its pacific sub-population has been decreasig sice 1956 until now. In order to grasp the char-acteristics of fluctuations of catches on a long-term basis and to estimate the level of catches in future, the long-term catch records after 1897 by large type set nets in the sea off three prefectures, Kanagawa, Mie and Krichi which are major fishing grounds for adult yellowtail in the Pacific coast of Japan have been investigated.
The results are summarized as follows;
1) There are two types of long-term fluctuations of the stock. During 1897-1955, it is the pertod of stable high-level stock. During 1956-1984, it is the other period of long-term decreasing stock.
2) On the long-term fluctuations, there are short-term fluctuations of a cycle of 9-10years.
3) It is estimated that the present stock level being on the decrease by yearly ratio of 0.918, has decreased by 14% in comparison with the level at 1956. Also present levels of the catches have decreased 6% at Kanagawa, 21% at Mie and 16% at Kôchi in com-parison with each levels in 1956, due to variation of space by oceanographic conditions.
4) Main factors of fluctuations of the stock in the period of stable high-level stock were divided into two natural factors, such as variabilities of oceanographic conditions and natural fluctuations of stock. But the main factor of long-term decreasing stock was estimated only as increased fishing intensity for immature yellowtail.
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Takeshi Yamane, Yunosuke Iitaka
1986 Volume 52 Issue 7 Pages
1189-1197
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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A series of experiments was performed with the purpose of getting the fundamental aspects of the virtual mass effects acting on the net gear motion. Three types of webbings; monofilament with double sheet bend, lmotless multifilaments and multifilaments with sheet bend, were used in the experiments. The motion offramed plane nets were recorded as the change in the force through the strain gauge on a recorder. The virtual mass of webbing consisting of multifilament with sheet bend became larger than the other two types. When inclined angle with respect to the moving direction was 0°, the virtual mass represented the maximum value in all cases. The virtual mass effects acting on the mesh size appeared clearly when mesh size became relatively small. The results suggest that the virtual mass of webbing is variable and depends upon the mesh size and the surface shape of webbing in addition to the state of motion.
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Nagahisa Uki, Takeshi Watanabe
1986 Volume 52 Issue 7 Pages
1199-1204
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Effect of heat-treatment of dietary proteins on their nutritional quality for the abalone
Haliotis discus hannai was investigated to clarify the reason for low dietary value of white fishmeal as a protein source in abalone diet. Casein and fishmeal prepared from pollock were exposed to various heat-treatments (80-130°C, 2h) and their nutritional quality as protein sources was compared with those without treatment or fresh fish meat by feeding abalone of different growth stages (13-56mm in shell length) with diets containing each of those protein sources.
The nutritional quality of dietary protein sources was found to be greatly affected by heat-treatment. The growth of abalone and feed conversion efficiency were remarkably reduced by feeding diets containing heat-treated casein or fishmeal. The influence of heat-treatment on the dietary value of protein sources was more marked in larger size of abalone. Thus it may be concluded that the inferior protein quality of white fishmeal to casein in abalone is due to the effect of heat during the manufacturing process of white fishmeal.
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Hiroto Maeda, Akira Kawai
1986 Volume 52 Issue 7 Pages
1205-1208
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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In order to study the detailed distribution and the composition of organic acids present in the lake sediments, a new analytical method was established and applied to the bottom sediments of Lake Biwa. Extraction of organic acids was carried out by the use of the method reported by Miyoshi and Neish. The ethyl ether extract was evaporated to dryness and converted to butyl esters by refluxing in butanol, H
2SO
4 and anhydrous sodium sulfate by Yamashita's method. Using a Hydrogen-flame ionization detector and glass column (3m×3mm i.d.) of SE-52 on chromosorb W on a Shimazu GC-6A, nitrogen flow rate of 40ml/min. and temperature program-ing between 45°C and 220°C at a rate of 6°C/min were selected as optimum condition of acid ester analysis. The average recovery of organic acids by the use of the above procedure was much higher than that of Koyama's silica-gel chromatography.
Identification and determination of organic acids in sediment samples from Lake Biwa were carried out and obtained:
In the bottom sediment, the organic acids detected were formic, acetic and regardless of the location and depth of the bottom sediments. In general Acetic acid was found in the highest concentration. The organic acids were not detected in the interstitial water of the sediment, but were found in adsorbed form on/in the sediment particles.
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Yukinori Takahashi, Toshiaki Itami, Kishiho Konegawa
1986 Volume 52 Issue 7 Pages
1209-1214
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The lysozyme was partially purified from the skin mucus of carp
Cyprinus carpio by chitin coated cellulose and carboxymethyl cellulose and examined for the enzymatic properties. On the electrophoretic analysis, the partially purified lysozyme appeared in two bands in SDS-polyacrylamide gel and the molecular weight of each was 24, 000 and 33, 000.
The partially purified lysozyme showed the maximum activity of the lysis of
Micrococcus lysodeikticus at 40°C in 0.01M phosphate buffer. The pH optima of this fraction were 7.2 in 0.01M phosphate buffer and 9.0 in glycine-NaOH buffer. The lysozyme of carp skin mucus heated at 100°C for 10 min in the acidic buffer (pH 3.5) was relatively stable but that in the neutral (pH 7.0) or the alkaline (pH 9.0) buffer was liable to be inactivated, as shown by the lysozyme from the hen egg-white.
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Katsuhiko Harada, Kazuya Fukuda, Manabu Sugihara
1986 Volume 52 Issue 7 Pages
1215-1224
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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In searching for a chemotaxis index, with special reference to repellence index of food, a logistic curve y
i=g/{1+exp[-r(j-a)]} was applied to the time-courses, the individual number observed y
i with passing time from j=1 to 10min for three behavior patterns of oriental weather-fish
Misgurnus anguillicaudatus which entered into, left from and remained in the test compartment containing repellence or attraction specimen. Of 32 time-courses estimated by two calculative methods for each behavior in the case by using 20 individuals: 31 entered, 24 left and 4 remained-time-courses fitted the logistic curve with 0.10 level by chi-square test.
Among the relationships between the difference or the ratio of the same coefficients in both the specimen and a dummy, and the storage days of the specimen prepared, the general evaluation of the repellence and the attraction through observable behavior accorded well with the difference of dummy-a minus specimen-a and the ratio of dummy-a divided by specimen-a in the entered. The difference or the ratio was over 0 or 1 in the repellence index and below 0 or 1 in the attraction index. The validity of these indexes was ascertained to the specimen prepared from three kinds of food organisms.
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Wataru Miki, Katsumi Yamaguchi, Shoji Konosu
1986 Volume 52 Issue 7 Pages
1225-1227
Published: July 25, 1986
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Commercial Spirulina powder differs in the carotenoid composition from preparation to prepazation. In order to elucidate the reason we analyzed carotenoids in
Spirulina maxima spray-dried at 80°C(Sml) and 200°C (SmII). The contents of carotenoids in SmI and SmII were 648 and 6.0 mg/100g, respectively. The main components identified in SmI were zeaxanthin (25%), myxoxanthophyll (13-17%), β-carotene (15%), . and echinenone (11-13%), and a rare carotenoid, 3'-hydroxyechinenone, was also detected at 7-11%. In SmII, only two carotenoids, zeaxanthinand β-cryptoxanthin were detected as major components, and presumably decomposed products were observed in appreciable proportions. Thus the marked discrepancies in the composition of carotenoids of dried Spirulina preparations are most probably due to their thermolability.
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Seiichi Ando, Mutsuo Hatano
1986 Volume 52 Issue 7 Pages
1229-1235
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The relation between gonadosomatic index (GSI) value and proximate composition of muscle of chum salmon at each migration stage did not markedly differ with the date and locality of capture. This might suggest that the situation of proximate composition can be characterized by the GSI value. The relation between GSI value and proximate composition was statistically evaluated by multiple regression analysis.
Total protein and sarcoplasmic protein contents of the muscle markedly decreased during spawning migration, while the contents of ninhydrin positive substances of non-protein nitrogenous compounds increased. A high level of muscle autolytic activity was observed in the muscle of the fish during spawning migration. The composition of muscle protein fractions at the same migratory stage did not differ greatly from fish to fish, regardless of the date and locality of capture.
Judging from the fact that proximate composition, protein composition, and autolytic activity of chum salmon muscle at the same migratory stage were almost the same regardless of the date and locality of capture, the changes described above during spawning migration were considered to be closely related to their physiological states.
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Seiichi Ando, Mutsuo Hatano
1986 Volume 52 Issue 7 Pages
1237-1241
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The degree of myofibrillar protein degradation during spawning migration of chum salmon
Oncorhynchus keta was evaluated by concentrating of muscle extracts by ion-exchange column chromatography, followed by measurement of
Nτ-methylhistidine (MeHis). The level of MeHis markedly increased during spawning migration, especially in female specimens. MeHis was detected in both myofibril and actin at feeding migration stage. These results indicated that muscle proteins of chum salmon were degraded during spawning migration, resulting in an increase of amino acids including MeHis in the muscle extracts.
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Koich Takizawa, Morihiro Sada, Emiko Okazaki, Taneko Suzuki
1986 Volume 52 Issue 7 Pages
1243-1248
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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Attempts were made to process the Antarctic krill
Euphausia superba meat into crab meat-textured protein fibers.
To frozen krill surimi or tail meat were added 4% NaCl and 1% NaHCO
3, and the mixture was homogenized in a vacuum food cutter to afford a viscous paste. The paste obtained was extruded from nozzles (1-2mm diameter) into ethanol at 15°C, and the fibers formed were kept immersed For 15 min. After washing with water, the fibers were steamed at 85°C for 30 min. The fibers thus obtained were examined for some physical properties by a rheometer. The fibers prepared from krill surimi or fresh tail meat showed physical parameters similar to kamaboko, whereas the fibers from deep-frozen krill tail meat showed those resembling boiled crab meat.
The physical properties of the fibers differed among the krill materials used, and also upon the conditions of the ethanol treatment: e. g., the lower the temperature and the higher the ethanol concentration, the higher the elongation ratio.
A possibility was indicated from these results that crab meat-textured protein fibers are processed from different krill materials by arranging the processing conditions.
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Toshio Akiyama, Takeshi Murai, Takeshi Nose
1986 Volume 52 Issue 7 Pages
1249-1254
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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In order to elucidate the mechanism for the occurrence of scoliosis as tryptophan deficiency symptom noted only in salmonids so far; tryptophan deficient diet with serotonin which is a trypto-phan metabolite and one of the brain neurotransmitters in mammals, was fed to chum salmon fry and checked for the incidence of scoliotic fish. We did not succeed both in complete prevention of the occurrence and in the restoration to normal fish by the oral administration of serotonin creatinine sulfate (25-300mg/100g diet), but the incidence of scoliosis was apparently lowered by the above treatment. In addition, a few spinal deformity was observed in the fish fed the tryptophan sufficient diet supplemented with
p-chlorophenylalanine (29mg/100g diet) which is a depleter of serotonln
in vivo.
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Toshio Akiyama, Takeshi Murai, Katsuyoshi Mori
1986 Volume 52 Issue 7 Pages
1255-1259
Published: July 25, 1986
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5-hydroxy-L-tryptopha (5-HTP) and kynurenine were supplemented to the tryptophan deficient diet to confirm if these substances can prevent occurrence of spinal deformity such as scoliosis caused by tryptophan deficiency. None of the fish showed scoliosis in the group fed the tryptophan deficient diet with 5-HTP (130mg/100g diet) for 4 weeks. However, scoliosis was recognized in 62% of the fish fed the tryptophan deficient diet with DL-kynurenine (240mg/100g diet). On the other hand, the administration (290mg/100g diet) of DL-
p-chlorophenyl-alanine (PCPA) to the diet with sufficient quantity of tryptophan resulted in a high incidence (64%) of spine-deformed fish, and the 5-HT content in the brain of PCPA treated group were significantly lower than that of the control group. These findings indicated that the occurrence of spinal deformity is related to the depletion of 5-HT in the body or the brain.
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Satoshi F. Noguchi
1986 Volume 52 Issue 7 Pages
1261-1270
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The present study was undertaken to clarify the continuous viscoelasticity changes of surimi during heating. A low frequency parallel plate type dynamic viscoelasticity measuring instru-went was used, with a programmable temperature control unit. The change in storage modulus of rigidity could be divided into at least eight characteristic regions. Four structure-forming regions and four critical or unstable regions appeared alternatively on increasing the temperature from 5 to 80°C. The mechanisms of setting and modori phenomena were investigated in con-nection with these regions. The role of myosin, which is the major component of meat gel, and the rlles of additives (sugars and polyphosphates) on gelation were also characterized. The results generally agreed with the results obtained by other measurements, and showed that the present methodology is very useful for determining the continuous viscoelastic changes of food gels during processing. The present methodology can be applied in the food industry in planning the combinations of additives and in searching for suitable heating conditions.
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Munehiko Tanaka, Yuji Nagashima, Takeshi Taguchi
1986 Volume 52 Issue 7 Pages
1271-1274
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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The model system containing histamine, glucose and microcrystalline cellulose was used to investigate the non-enzymatic browning reaction. The kinetics of the brown pigment formation and loss of histamine were studied as a function of heating temperature, pH and water activity of the systems. The rates of the brown pigment formation and the histamine loss followed zero order after an initial induction period and first order kinetics of up to a loss of at least 50% level, respectively. These rates increased with increasing temperature and pH, and decreasing water activity. The activation energies of both reactions were in the range of 23-24 kcal/mol for the pigment production, 17-21 kcal/mol for the histamine loss. It was suggested that the content of histamine can be reduced by controlling the condition of the model systems before brown dis-coloration becomes appreciable.
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Koji Nakamura, Haruka Iida
1986 Volume 52 Issue 7 Pages
1275-1279
Published: July 25, 1986
Released on J-STAGE: February 29, 2008
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To elucidate the relationship between riboflavin content and body color (melanin content), albinic juvenile flounder
Paralicthys olivaceus were examined for riboflavin in the skin and muscle.
In the normal juvenile fluounder, the riboflavin content reached 1, 200μg/100g in the black skin of the ocular side. The values obtained from the albinic individuals were less than one tenth of that of the normal ones; the more the degree of albinism, the smaller the amount of riboflavin. There was little difference between the albinic and the normal individuals as for riboflavin content in the blind side. The riboflavin content in the muscle of the normal individuals was roughly proportional to that in the skin and was higher in the ocular side than in the blind side.
In piebald individuals the riboflavin content of the skin was remarkably higher in the black part than in the white part.
It was confirmed by paper chromatography that all of the riboflavin in the skin of both the norrnal and the albinic individuals existed as free type.
From the above results, it seems that there is a close relationship between riboflavin con-tent and body color (melanin content). As riboflavin is a photosensitive substance, melanin formation should be accelerated by its photosensitive action under the sun light.
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Eiji Niwa, Satoshi Kanoh, Teruo Nakayama
1986 Volume 52 Issue 7 Pages
1281
Published: July 25, 1986
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Tasuku Watanabe, Yuzuru Suzuki
1986 Volume 52 Issue 7 Pages
1283
Published: July 25, 1986
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