Differences by sex in the composition of plasma protein, its hormonal control and relation-ship between plasma protein and yolk protein of Ayu, Plecoglossus altivelis, were studied elec-trophoretically and immunologically. In immunoelectrophoresis, two new proteins (Fm-a and Fm-b) appeared in the female plasma with the commencement of vitellogenesis. Fm-a was composed of two fractions (fractions 9 and 11) in starch-gel electrophoresis, which increased in the maturing female plasma. In males, the appearance of new protein was not observed. Estradiol-17β and estradiol-benzoate induced the dose-dependent synthesis of the new specific proteins in male fish, but testosterone, testosterone-propionate, hydrocortisone acetate and progesterone failed to produce the specific proteins. Ovarian extract caused three precipitin bands (Eg-a, Eg-b and Eg-c) in response to anti-maturing female Ayu plasma. Fm-a and Eg-a (a dominant fraction of ovarian extract) had the same antigenic component and binding sub-stances such as calcium, lipid and polysaccharide. Eg-a was also composed of two fractions in starch-gel electr ophoresis. In maturing females, plasma calcium increased simultaneously with the appearance of new specific protein and in estrogen-treated males (dose-dependent). These results suggest that in maturing female Ayu, new specific proteins, formed outside the ovary with the stimulation of estrogen, appear in the female plasma and then are taken up by the oocyte with the commencement of vitellogenesis.

抄録全体を表示

Histological observations were carried out to confirm the increase of protein synthetic activity in the liver parenchymal cells of Ayu following gonadal maturation and estrogen ad-ministration by light and electron microscopy. Sexual dimorphism was recognized in the liver cells of maturing fish. Nuclei and nucleoli were highly hypertrophied and RNA increased in liver cells of maturing females. On the other hand, such a change was not observed in the male. Estrogen treatment induced a hypertrophy of nuclei and nucleoli, an increase of RNA and a remarkable proliferation of rER in the cells of both immature and mature males. These histological results indicate an increase of protein synthetic activity, suggesting that the newly formed FSPP is synthesized in the liver cells under the influence of female hormone, estrogen.

抄録全体を表示

The cerebral (CG), pleuro-pedal (PPG) and visceral ganglia (VG) of mature females of the abalone, Nordotis discus R_EEVE, were respectively homogenized separately in filtered sea water, in tap water or in 0.6% NaCI solution in a concentration of one ganglion per 0.1 ml of the vehicle. The homogenates were injected 1, 2 or 3 times, once a day, in a constant amount of 0.1 ml per animal, into the head of prespawning females of 9.0-11.9 cm in shell length.
In groups of PPG-, PPG+VG- and VG-injected animals, ovaries exhibited a remarkable swelling and softening followed by a slight increase in mean body weight, possibly owing to an increased water content in the ovaries caused by the uptake of water. Moreover, they spawned a huge number of fertilizable eggs after 1 or 2 injections, which resulted in a loss in body weight. Conversely, a group of CG-injected animals showed a gain in mean body weight without revealing any notable change in the ovaries.
It seems likely that the visceral and pleuro-pedal ganglia may produce and release sub-stance(s) which induces spawning in the abalone, and that an uptake of water in the pre-spawning ovary might be physiologically significant for the execution of spawning.

抄録全体を表示

The population growth of the rotifer, Brachionus plicatilis cultured with a marine species of Chlorella suspended at various densities was investigated.
Experiments were performed by culturing many individuals in many test tubes each containing two individuals in the experimental medium. From daily counts of eggs laid and surviving individuals, time intervals from hatching to 50% survival and to peak of fecundity, net reproduction rate, intrinsic rate of population increase and mean generation time were estimated.
The results obtained are summarized as follows.
1. The values of the indices concerning population growth of the rotifer indicate that for its mass production the marine Chlorella should be kept always at the density of 85-213×10⁴ cells/ml, where 150 ×10⁴ cells/ml may be the most desirable because of the highest values of intrinsic rate of population increase and net reproduction rate.
2. Population growth of the rotifer can be restrained in Chlorella suspension even at the density (less than 213×10⁴ cells/ml) where the rotifer can not reach a satiated condition.
3. The weight and volume of the Chlorella were estimated at 7.1×10^-6μg and 1 ×10^-8mm³ per average cell, respectively. Therefore, the most suitable density for population growth of the rotifer is estimated as 10.7μg/ml or 1.5×10^-2mm³/ml.

抄録全体を表示

The nutritional effect of caked yeast still living and of dried marine yeast on the rotifer, Brachionus plicatilis, was examined.
Experiments were performed by culturing many individuals in many test tubes, each containing two individuals in the experimental medium. From daily counts of eggs laid and surviving individuals, time intervals from hatching to 50% survival and to peak of fecundity, net reproduction rate, intrinsic rate of population increase and mean generation time were estimated.
The results obtained are summarized as follows.
1. Caked yeast still living, Rhodotorula sp. has less nutritional effect on the rotifer than that of the marine Chlorella. However, it seems to be somewhat effective as food for the rotifer.
2. Dried marine yeast itself has little nutritional effect on the rotifer. However, aerobical decomposition can increase the nutritional effect to some extent.
3. The marine yeast added to a diluted Chlorella suspension was very effective as supplementary food for the rotifer. Hence, yeast may be used most effectively as a sup-plementary food in the culture medium when sufficient phytoplankton can not be supplied to the rotifer.

抄録全体を表示

Several papers have reported on the uptake of polychlorinated biphenyl (PCB) in fish exposed to diluted PCB solution. However, toxicological studies on the oral administra-tion of PCB have not been reported so far.
In the present investigation, changes in blood characteristics and plasma enzyme activ-ities of carp, Cyprinus carpio, fed with diets containing 5, 25 and 100ppm of PCB (Aroclor 1248) were examined. After 7 or 20 days feeding with PCB-containing diets, the carps were sacrificed for chemical analyses. The results obtained are as follows.
1) After 7 days feeding, the blood glucose content and the hematocrit value in 5 and 25 ppm groups appeared decreased, while in the 100ppm group both values showed an increasing tendency. After 20 days feeding, however, the blood glucose content and the hematocrit values were elevated with the dose of PCB.
2) The protein content, β-glucuronidase and glutamate pyruvate transaminase activi-ties showed an increasing tendency.
3) After 20 days feeding, the glutamate oxaloacetate transaminase activity and alka-line phosphatase activity were remarkably increased.
4) The findings suggest that plasma β-glucuronidase activity may be a useful index for examining the effect of PCB in fish.

抄録全体を表示

Carp, Cyprinus carpio, were fed for 7 and 20 days, respectively, with diets containing 5, 25 and 100 ppm of PCB (Aroclor 1248) and analyzed gas chromatographically for its accumulation in various tissues.
PCB was detected in all the tissues analyzed. In hepatopancreas, the greatest amount of PCB was found. It was followed by the intestine, kidney, gill, skin, and ordinary muscle. The amount of accumulation seemed almost parallel to the crude fat content in the tissue. Accumulation factors were different among the tissues. The gas chromatographic patterns of the once- absorbed PCB was generally different from that of the standard PCB mixture administered. With the hepatopancreas, gill, and kidney, contents of the lowly chlorinated PCB isomers were relatively increased, while those of the highly chlorinated PCB isomers decreased. With the ordinary muscle, an inverse tendency was recognized. However, no marked changes in the PCB pattern were observed in the intestine. The results suggest that each isomer of PCB is almost equally absorbed from the intestinal tract and transported to the different tissues in carp.

抄録全体を表示

Following previous reports, the diel vertical migration of a population of Aurelia aurita medusae was again studied at the outer-western part of Urazoko Bay for a period of 25 hours, from 10:00, May 27 to 11:00, May 28 1970.
Sampling was made every two or three hours by means of simultaneous horizontal hauls of four plankton-nets (100cm in mouth diameter and 10mm in mesh size) at the surface, 3, 7 and 13 meters deep, respectively for 10 minutes at a speed of 0.5 m/sec. Meteorological and hydrographic observations were also recorded. The results obtained are:
1) Collected medusae ranged from 3 to 12 cm in bell-diameter were all immature. Although they were all distributed at the bottom layer below 10 meter depths in the day time under fine weather conditions, about 50 percent of them migrated to the surface at 17:00. Around sunset, they were distributed almost evenly from surface to bottom layer. Later on, they were captured mainly from the bottom layer when the night was dark. The next morning, when it was fine, most of them appeared to move up to the surface at 6:30. However, their main distribution layer moved gradually to the middle layer, about 6 meters in depth at 9:00 and later again down to the bottom layer at 10:30.
2) The main factor controlling the diel vertical migration of Aurelia medusae was again confirmed to be underwater illumination.

抄録全体を表示

The PCB contents of 30 species of marine animals in Tokyo Bay were determined. Four species of fish caught around Hateruma Island, Okinawa, were also analysed for comparison with those in Tokyo Bay. The results are as follows:
1. Several extraction methods were tested using the tissues of dragonet and short-necked clam. Nearly the same values were obtained by all except the direct-alkali-digestion method which gave values 1.5 times higher than the others.
2. PCB values of fish meats from Okinawa were found to be between 0.02-0.1ppm.
3. In the samples from Tokyo Bay, the maximum value was 2ppm in puffer and the minimum, 0.01ppm in bloody clam, Tsunoakeusu and sea squirt. All these results suggested that the accumulation of PCB might be caused by a food chain.
4. The highest PCB value based on fat content was 603ppm in the meat of spotted shark.
5. The PCB values of viscera were always higher than those of meat, on a whole as well as a fat basis. However, on a fat basis, the differences between viscera and meat values were somewhat smaller.
6. The gas chromatographic patterns of PCB in the samples differed not only between fish species but also between the viscera and meat of the same fish.

抄録全体を表示

In succession to the preceding two reports, this paper deals with the effect of storage humidity upon the fluctuation of sugars, fatty acids, and free amino acids contents in dried laver “Nori’.
1) No notable difference was observed in the glucose content between “Nori” samples stored under dry and humid conditions respectively. Galactose content showed little flucturation under dry conditions, but under humid conditions rapidly increased to a maximum of about ten times its initial amount and then decreased gradually.
2) The content of floridoside decreased rapidly under humid conditions while it decreased slowly under dry conditions, a dendency which is in contrast to that of galactose.
3) One of the unidentified components, which is deduced to be isofloridoside, showed a fluctuation pattern, which resembles that of floridoside.
4) An apparent increase in the content of fatty acids under humid conditions was presumed to be due to some histological change which is favorable to the extraction of lipids.
5) The free amino acid content of “Nori” was kept almost constant regardless of the storage humidity.

抄録全体を表示

The proteolytic activity of the jellied meat of yellowfin tuna was examined. Extracts of the jellied meat exhibited maximal hemoglobin splitting activity at pH 3. The pH-activity curves of the jellied and normal meat extracts were qualitatively similar. The activity of the jellied meat in the advanced stage of degradation of the muscle architecture was found to be three-fold greater than that of the normal meat. The activity of the muscle in an earlier stage was about one and a half-fold higher than the normal level. The extract of the muscle adjacent to the jellied portion where no abnormality could be observed from the external appearance showed about the same level of activity as that in the jellied portion of the same fillet.

抄録全体を表示

Activities of various glycosidases in hepatopancreas and digestive tract of the ascidian, Halocynthia roretzi, were determined.
Among arylglycosidases, β-galactosidase exhibited the strongest activity. As for poly-saccharidases, the extremely high activity was found with laminaranase followed by amylase(s). Although activities of xylanase, pectinase, and cellulase (CMC hydrolase) were clearly, detected, activities of other polysaccharidases, especially chitinase, alginase, and cellulase (cellulose hydrolase), were very low.
Storage carbohydrates such as laminaran and starch in algae and phytoplankton may be important nutrients for the animal.

抄録全体を表示

Ciguaterin, an emetic factor, was extracted from the liver of the red snapper Lutjanus bohar from the Ryukyu Islands and purified by column chromatography using ion-exchange resins, acidic alumina, silicic acid, and Sephadex G-10 successively. The final product evoked vomiting in cats within 30min at a dose as low as 3μg/kg. It was however still contaminated by a few ninhydrin-positive substances, as shown by thin-layer chromato-graphy.
The purified emetic was positive to ninhydrin, peptide and Pauly reagents, but negative to Dragendorff and sugar reagents. It showed only a slight shoulder near 330nm in the ultraviolet region. On acid hydrolysis, it afforded 14 amino acids, of which lysine, glutamic and aspartic acids were prominent. Total amino acid residues accounted for 40 per cent of the solid. These results suggest that ciguaterin possesses a peptide moiety.

抄録全体を表示

The microdiffusion-K₂Cr₂O₇ oxidation method of Conway & Nolan was modified for the determination of EtOH in “shiokara”, a kind of cured fermented marine product, so as to remove some obstructive compounds such as formaldehyde, acetaldehyde, etc..
The proposed method is as follows;
1. 9% PC or TCA extracts from “shiokara” containing 50-250μg EtOH per 0.5ml, can be used as sample solutions.
2. In order to evaporate EtOH completely, the K₂C0₃ concentration in the outside chamber of the unit should be more than 37.5%. The recommended conditions are 3 hours at 30°C or 1.5 hours at 50°C.
3. When the samples contain carbonyl compounds which obstruct the determination of EtOH, the addition of thiosemicarbazid hydrochloride to the sample solutions effectively eliminates interference by these compounds.
The EtOH contents of several cured fermented marine products, such as so called “shiokara” and “nukazuke”, were determined by using the modified method.

抄録全体を表示

Relative stabilities of the actomyosins from sei whale, bluefin tuna, and two flat fishes, Microstomus achne and Limanda herzensteini, were measured in terms of the inactivation of Ca²⁺-ATPase. The sequence of stability was whale, tuna, and flat fishes respectively. The heat denaturation constant K_D of whale was in close proximity to that of the rabbit, though lower than it. The K_D of tuna was lowest among the fishes, while that of L. herzensteini was highest.
This sequence of stability remained the same when actomyosin Ca²⁺-ATPase was denatured by urea.
On the basis of these findings, the corelationship between the adaptability of actomyosin, the physiological conditions, and the natural environments, is discussed.

抄録全体を表示

Muen-surimi of different qualities were prepared from dewatered muscle stored at 3°C or 5°C for various time intervals and Kaen-surimi of different qualities were prepared from muscle paste containing 2.5 % NaCl and stored at 20°C for various time intervals. The amount of actomyosin in surimi was determined as Ca²⁺-ATPase total activity and the quality of Kamaboko from the same material was determined by its jelly strength and folding test.
1. It was found that a decrease in the amount of actomyosin in surimi and concomitant deterioration of the quality of Kamaboko prepared from the same material occurred with respect to the length of storage of raw material.
2. In all of the surimi studied, it was found that the decrease in the amount of acto-myosin was correlative with the inactivation of Ca²⁺-ATPase, and not with the insolubility of salt soluble protein. Inactivation of Ca²⁺-ATPase and simultaneous insolubility of salt soluble protein were observed when ‘setting’ of the muscle paste proceeded markedly.
3. It was confirmed that there was a clear relationship between the amount of acto-myosin in surimi and the quality of Kamaboko as assessed by the folding test.

抄録全体を表示

Actin was extracted from the acetone dried muscle powder of tilapia, Tilapia mossambica, and purified by reversible polymerization and gel filtration on Sephadex G-200 to electro-phoretic homogeneity as shown by SDS-polyacrylamide gels.
The purified G-actin retains the ability to polymerize into F-actin in the presence of 0.1_M KCI plus 1m_M MgCl_2. Its mobility on SDS-polyacrylamide gel electrophoresis is identical with that of carp and rabbit actin.
The purified actin complexed with tilapia myosin to form actomyosin desensitized to the action of Ca²⁺; in the absence of Ca²⁺, superprecipitation of the synthetic actomyosin was inhibited by the addition of a tropomyosin-troponin complex prepared from tilapia or carp muscle, the addition of Ca²⁺ releasing the inhibition. These observations clearly indicate that the actin, purified from tilapia muscle, is devoid of the tropomyosin-troponin complex.

抄録全体を表示