Showing papers in "Nippon Suisan Gakkaishi in 1972"
TL;DR: The bacterium was found to be not identical in its biochemical characteristics and pathogenicity to fish to any formally established species of the genus Pseudomonas, and thus it is suggested that it be identified as pseudomonas anguilliseptica sp.
Abstract: Outbreaks of a new bacterial disease ‘Sekiten-byo’ (red spot disease) caused mass mortalities among pond-cultured eel populations in both Shizuoka and Tokushima prefectures during late spring to early summer in 1971. A remarkable petechial hemorrhage in the body surface appeared to be the sole characteristic symptom of the disease. Generally, a great mumber of bacteria were found in the blood of moribund fish. The causative organism is a Gram-negative, non-acid-fast, nonsporing rod with a single polar flagellum, measuring about 2×0.4μ. The bacilli have metachromatic granules. Growth of the bacterium on a nutrient agar medium was rather slow. Colonies after 72 hr incubation at 25°C on nutrient agar were uniformly round, 1mm or less in diameter, glistening, light grey, entire, convex, translucent and vicid. Mortility of the organism varied with incubation temperature. Because of the production of oxidase, nonsensitiveness to vibriostat 0/129 and inability both to attack glucose and to produce diffusible pigment, the bacterium is placed in the genus Pseudomonas, group III or IV. The bacterium was found to be not identical in its biochemical characteristics and pathogenicity to fish to any formally established species of the genus Pseudomonas, and thus we suggest that it be identified as Pseudomonas anguilliseptica sp. nov.
105 citations
TL;DR: Assuming that the filtration rate measured at a definite Colorella density indicates the physiological activity of the rotifer under various culture conditions, the above-mentioned conditions are the most suitable to exhibit its physiological activity to the highest degree.
Abstract: In the present study, the filtration rate and the ingestion rate of the rotifer, Brachionus plicatilis, were investigated under various culture conditions. Several groups of the rotifer varying in density were cultured for 60min, in an experimental medium containing a species of marine Chlorella at a definite density. The filtration and ingestion rates of the rotifer were then estimated by measuring the optical density of Chlorella as the phytoplankton density in the media. The rotifer used in these experiments was pre-cultured in two ways. In one case the rotifer was made to have food in its stomach by feeding in the experimental medium (satiated condition) and in the other case the rotifer was made to have an empty stomach (empty condition). Results obtained are as follows. 1. When the rotifer is fed with Chlorella in the test medium kept at a density of less than about 213×104 cells/ml, the rotifer maintained its filtration rate at the highest and almost constant level of about (7-10)×10-5 (empty condition) and (5-7)×10-5ml (satiated condition) per min. per individual while the ingestion rate continued to increase. Above this density of Chlorella, the filtration rate decreased with the increase of the density of Chlorella in the test medium while the ingestion rate maintained an almost constant level of about 200 cells/min/individual under the empty condition. This tendency of ingestion rate could not be observed distinctly in the rotifer under the satiated condition. 2. The filtration rate measured under the satiated condition showed its highest in the media having a temperature over 22.0°C, chlorinity at about 7.8% and pH value at 8.0. 3. Assuming that the filtration rate measured at a definite Colorella density indicates the physiological activity of the rotifer under various culture conditions, the above-mentioned conditions are the most suitable to exhibit its physiological activity to the highest degree. Therefore, the above conditions seem to be the most favorable for the culture of this rotifer.
88 citations
TL;DR: Eugenol (4-allyl-2methoxyphenol) was found to exhibit an anesthetic effect on various fishes as mentioned in this paper, including rainbow trout, Carassius auratus, medaka, Oryzias latipes and crucian carp.
Abstract: Eugenol (4-allyl-2-methoxyphenol) was found to exhibit an anesthetic effect on various fishes. Carp, Cyprinus carpio, medaka, Oryzias latipes, crucian carp, Carassius auratus and rainbow trout, Salmo gairdnerii irideus were anesthetized in a short time in water containing 12.5 to 100 ppm of eugenol as added to water in the form of FA-100 (a pharmaceutical preparation of 10% eugenol). Eugenol was effective at only one fourth the concentration of MS-222 that would give comparable effects in gold fish, Carassius auratus, medaka and crucian carp. Anesthesia by FA-100 and recovery from it required longer time at low water temperatures (5 and 10°C) than at normal temperature (24.5°C).
70 citations
TL;DR: Clinical aspects of this deficiency disease are dramatic attesting to the essential function of this diet ingredient in normal processes.
Abstract: Salmon, trout, char, carp, aquarium fish and probably many more kinds of fishes develop specific avitaminosis C symptoms when denied dietary sources of ascorbic acid. Clinical aspects of this deficiency disease are dramatic attesting to the essential function of this diet ingredient in normal processes. Subclinical manifestations of the disease may play even more important roles in resistance to bacterial or viral infection, and certainly adequate ascorbate circulating and tissue storage levels would be critical deter-minants for repair of those tissues damaged by parasitic invasion or physical contusions.
64 citations
TL;DR: The results suggest that the indigenous bacterial groups (I-a1 and I-a11) are uniquely resistant or adapted to the environmental conditions in the stomach of marine fish.
Abstract: The response of some representative strains of the indigenous and the other bacterial groups isolated from the digestive tracts of marine fish to the environmental conditions to be encountered in the stomach, i.e. low pH value and gastric juice, was examined. The results obtained are summarized as follows: (1) In the cases of the indigenous bacterial groups (I-a1 and I-a11) and IV group, viability was not much influenced by 5 hour's incubation at pH 4.0; however, remarkable loss in viability was observed in the other groups under the same conditions. The turbidity of cell suspensions, in general, did not decrease markedly on incubation at pH 4.0. (2) When gastric juice prepared from red sea bream was added to the pH 4.0 suspension, the viability of the strains of I-d and VI-b groups was significantly decreased after 5 hours' incubation. A marked decrease in turbidity was also observed with the strains of III, VI-b and VII groups, in the presence of gastric juice at pH 4.0. Pepsin, lysozyme and gastric juice from gizzard shad did not decrease the viability. (3) The strains of the indigenous bacterial and VI-b groups grew well at pH 5.0, while the others did not grow under this condition. These facts suggest that the indigenous bacterial groups (I-a1 and I-a11) are uniquely resistant or adapted to the environmental conditions in the stomach of marine fish.
62 citations
TL;DR: Zeaxanthin was metabolized easily, but β-carotene was metabolizes very slightly, and the hepatopancreas did not accumulate all given carotenoids.
Abstract: 1) Zeaxanthin and β-carotene were metabolized to astaxanthin. Zeaxanthin was metabolized easily, but β-carotene was metabolized very slightly. Echinenone and canthaxanthin were not metabolized distinctly to astaxanthin. Lutein was metabolized to 4-ketolutein but not to astaxanthin. 2) The rates of accumulation and absorption of carotenoids differed. OH groups and α-structure increased the absorption but carbonyl group decreased it. 3) The hepatopancreas did not accumulate all given carotenoids.
62 citations
TL;DR: The organism was non-motile displaying a fairly uniform morphology and did not utilize citrate and failed to grow in a potassium cyanide medium, and was catalase and oxidase positive.
Abstract: Since 1969, bacterial pseudotuberculosis has been associated with serious mortarity of cultured young yellowtails during the summer months in many yellowtail farms on the west coast of Japan. The disease is characterized by the deposition of greyish white bacterial colonies, each covering an area of approximately 0.5-1.0mm at innumerable sites in the spleen and the kidney. The cultures isolated from spleen and kidney lesions were small Gram-negative rods. In some instances, cultures from spleens and kidneys yielded an almost pure growth of this organism on nutrient agar and on blood agar. The organism grew in tiny, non-haemolytic, dew drop-like colonies on nutrient agar at 25°C in 48 hours; there was no growth at 35°C. The colonies had a margarin-like consistency. The organism was non-motile displaying a fairly uniform morphology. Acid was produced in glucose, fructose, galactose and mannose; but on gas production was evident; there was no observable reaction in xylose, arabinose, rhamnose, saccharose, maltose, trehalose, mannitol, lactose, sorbitol, salicin and dulcitol. The organism did not utilize citrate and failed to grow in a potassium cyanide medium. It was catalase and oxidase positive. The organism was therefore identified as Pasteurella piscicida JANSSEN and SURGALLA (1968).
57 citations
TL;DR: It was established that eels require the same 10 kinds of amino acid reported to be essential for salmonids and others.
Abstract: Essential amino acids for the 2 species of eel, A. anguilla and A. japonica, were examined by using an amino acid test diet. Forty fish were grouped in each aquarium and fed the test diets for a period of 6 weeks. In the both species, the fish fed diets deficient in each of alanine, aspartic acid, cystine, glutamic acid, glycine, proline, and tyrosine grew as well as those fed the complete amino acid diet. The fish fed diets deficient in each of arginine, histidine, isoleucine, leucine, lysine. methionine, phenylalanine, threonine, tryptophan, and valine failed to grow until the deleted amino acid was added to the ration. It was thus established that eels require the same 10 kinds of amino acid reported to be essential for salmonids and others.
44 citations
TL;DR: A member of the imperfect fungi was isolated on a soytone-dextrose agar medium with chloramphenicol and cycloheximide from gill lesions of Penaeus japonicus BATE infected with black gill disease and fits best in the genus Fusarium.
Abstract: A member of the imperfect fungi was isolated on a soytone-dextrose agar medium with chloramphenicol and cycloheximide from gill lesions of Penaeus japonicus BATE infected with black gill disease. Intramusculaly inoculation of conidia of the fungus caused invariably black gill disease in prawns, and the fungus could be isolated from gill lesions of artificially-infected prawns. The gills of healthy prawns were alway free of the fungus. Therefore the fungus was regarded as the pathogenic agent of black gill disease. The fungus produces mainly 4-celled, canoe-shaped macroconidia and 1-celled microconidia. Usually the mycelium is hyaline, but it characteristically produces a brown pigment when grown on the above-mentioned medium, salt Sabouraud's medium, and a salt potato-dextrose agar medium. On the basis of morphological criteria, this fungus fits best in the genus Fusarium.
44 citations
41 citations
TL;DR: Premature maturation was brought about in cultivated male Japanese eels by the injection of synahorin and the spermatogenesis of the fish was then studied cytologically and it resembles that of Anguilla vulgaris.
Abstract: Premature maturation was brought about in cultivated male Japanese eels by the injection of synahorin and the spermatogenesis of the fish was then studied cytologically. The results obtained were as follows: 1. The eels which were reared in sea water only showed on changes in testicular maturity in the early and late multiplication stages. Fish treated with synahorin, when transferred to sea water, exhibited a marked change in maturity and those injected with 200 or 300 ru synahorin showed marked secondary sex characters. Their testes, which arrived at the spermatocyte stage, after being treated four times with synahorin (each time with 100 ru), showed the appearance of spermatozoa in the lobule lumen, and after the sixth treatment with the hormone, the extrusion of sperm occurred in the fish. The spermatozoa obtained showed high motility in sea water. 2. The morphology of the germ cell during spermatogenesis has been described and it resembles that of Anguilla vulgaris already reported. Based on their histological characteristics, the testicular maturity of the eel has been divided into the following five stages. 1) early multiplication stage, 2) late multiplication stage, 3) spermatocyte stage, 4) sperm formation stage, 5) ripe stage.
TL;DR: The increase in pepsin-like enzyme activity and stagnancy of trypsin- like enzyme activity indicate that the digestive mechanism of proteins converts to a higher developmental level during the transitional stage from larvae to juveniles.
Abstract: Relationships between the developmental process of the digestive system and changes in activities of digestive enzymes during larval and juvenile stage of Ayu, Plecoglossus altivelis, were investigated. Two important periods are recognized in the developmental process of the digestive system. One occurs in the late stage of prelarvae, when the basic structure is established, the other, in the transitional stage from larvae to juveniles, when gastric glands develop and pyloric caeca differentiate. The development of the digestive system to one adult-like in function is accompanied with changes in body form and depth. The activity of amylase was recognized in larvae measuring about 25mm after which it increased to a fixed level in the juvenile stage. Though pepsin-like enzyme is scarcely detected in larvae measuring about 25mm, it abruptly increased in activity in juveniles measuring 35mm in which gastric gland is fully developed functionally. On the other hand, trypsin-like enzyme hardly increased in activity during transition from larvae to juveniles. The increase in pepsin-like enzyme activity and stagnancy of trypsin-like enzyme activity indicate that the digestive mechanism of proteins converts to a higher developmental level during the transitional stage from larvae to juveniles.
TL;DR: Scale resorption was found to occur in the precocious male parr of the masu salmon (Oncorhynchus masou) during autumn and winter and a histological study was made on those resorbing scales and the associated cells.
Abstract: Scale resorption was found to occur in the precocious male parr of the masu salmon (Oncorhynchus masou) during autumn and winter. A histological study was made on those resorbing scales and the associated cells. Resorption commences at the posterior scale margin and advances gradually to the anterior. In a cross section, both the osseous layer and the fibrillary plate seem to be affected successively by the activity of cells attached around the resorbing margin. In the early phase of reorption, these cells show a morphological resemblance to those of the growing scale margin. After considerable destruction of the margin, however, there appear multinucleated giant cells which are similar to the osteoclasts of bone tissues. It is presumed that the cells involved in the resorption of the scale may be derived from ancestor cells in the connective tissue of the scale pocket, or from a functional conversion of the scale forming cells.
TL;DR: In this article, the Latent Activity of Glucose-6-phosphatase (G6Pase) was found to be 1/3-1/7 higher than the reported value for rat liver.
Abstract: Distribution of hexokinase, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), and glucose-6-phosphatase (G6Pase) in fiish tissue was investigated to estimate the latent activity of glucose metabolism. The hepatic hexokinase activity of fish, which is regarded as an activity of glucose uptake into the metabolic pathway, is 1/3-1/7 that of the reported value for rat liver, and there are no extreme differences among the activities of the four species investigated. From the activities of hepatic enzymes relating to the Embden-Meyerhoff pathway (PGM and PGI) and to the hexosemonophosphate shunt (G6PD and 6PGD), grass carp is considered to posssess the strongest latent activity of glucose metabolism, being followed by eel, carp, and rainbow trout.
TL;DR: Compared to the gastropods, the pelecypods appeared to contain relatively small amount of cholesterol and revealed the very complex composition of sterols, while the chiton, Liolophura japonica, belonging to the most primitive mollusks, was found to contain 7-cholestenol contrasting that of the other mollsusks.
Abstract: From the viewpoint of comparative biochemistry, the sterol compositions of mollusks belonging to the class Gastropoda (three orders, nine families, sixteen genera, seventeen species), Pelecypoda (two orders, three families, three genera, three species), and Polyplacophora (one species) were investigated by using gas-liquid chromatography on 1.5% OV-17. The gastropods were found to contain cholesterol as a main sterol. In the case of Murex asianus, Cymatiidae sp., Charonia sauliae, and Conomurex luhuanus, however, other C27- and C28- sterols were detected in addition to cholesterol (42-64%). Compared to the gastropods, the pelecypods appeared to contain relatively small amount of cholesterol (26-35%) and revealed the very complex composition of sterols. On the other hand, the chiton, Liolophura japonica, belonging to the most primitive mollusks, was found to contain 7-cholestenol ( ?? 7-sterol) contrasting that of the other mollusks.
TL;DR: The above characters suggest that the pseudotuberculosis organisms have a close relationship with coryneform bacteria and genus Arthrobacter seemed to be the most suitable genus to which they belong.
Abstract: Morphological and biochemical characteristics were examined on four strains of the bacteria causative of “pseudotuberculosis” among yellowtail (Seriola quinqueradiata), and on a strain of Pasteurella piscicida, Janssen et Surgalla. The observation that the pseudotuberculosis organisms were identical with P. piscicida was confirmed. These organisms were all Gram-intermediate, non-motile rods. A peculiar morphological feature of the organisms is the transformation from rod-shaped cells in the early logarithmic growth phase to small coccoids or cocci in the stationary phase. The organisms gave positive Kovacs' oxidase reaction; fermented glucose in Hugh-Leifson's medium, and produced acid but no gas from a few other carbohydrates such as fructose, galactose, and mannose. They were sentistive to most of the antibiotics and antimicrobial drugs, including penicillin and polymyxin B; were halophilic; and did not grow at pH lower than 6.1. Although the cells of these organisms did not show any typical coryneform appearance, nevertheless, the above characters suggest that they have a close relationship with coryneform bacteria and genus Arthrobacter seemed to be the most suitable genus to which they belong.
TL;DR: Although there was a little variation in the numbers of bacteria in the digestive contents among the three dietary groups of fish, in morphological and biochemical properties the bacteria isolated resembled one another in spite of difference of diet.
Abstract: A comparison of the properties of the becterial flora present in the digestive tracts of fish, red sea bream snapper and crimson sea bream, which were fed with three different diets (F-, C- and S-diet), was carried out. The results were summarized as follows: (1) Although there was a little variation in the numbers of bacteria in the digestive contents among the three dietary groups of fish, in morphological and biochemical properties the bacteria isolated resembled one another in spite of difference of diet. (2) The majority of strains isolated from environmental sea water were different from those isolated from fish in the abilities to produce indol and to hydrolyse starch and casein. A dominant group having a certain definite property was not found among the strains isolated from C-diet. (3) The growth of bacteria isolated from fish was not affected by bile or low pH value, while that of bacteria isolated from sea water and diet was affected. It is suggested that the flora in the digestive tract are limited to only a few bacterial groups, since the environmental conditions in the digestive tract are so severe as to exclude the great majority of exotic bacteria.
TL;DR: No chromaticity-type S-potentials were recorded from the retina of skipjack tuna and two other related species, which indicates that the species are probably color-blind.
Abstract: No chromaticity-type S-potentials were recorded from the retina of skipjack tuna and two other related species. This, together with a maximal response at about 497 nanometers from the only spectral pattern of the luminosity type, indicates that the species are probably color-blind. Ganglia cell responses and electroretiongrams also supported this view.
TL;DR: The remarkable diurnal changes of distribution of Engraulis japonica at surface layers are caused by vertical migration of larger sized larvae.
Abstract: More than 400 towings of surface and sub-surface layers were carried out to obtain informations on the distributional features of larval fish in the waters off central Japan. The results obtained are as follows: (1) More than 72000 individuals of larval fish were collected. Abundance in both number of species and individuals was high during spring to summer and most of these samples were represented by Engraulis japonica, Scomber japonicus, Trachurus japonicus, Myctophum asperum, Thunnus thynnus and Sebastes inermis, given in the order of abundance. (2) Larval forms are classified into the following three types from their vertical distributions; (i) species appearing only at surface layers, (ii) species appearing at layers far below the surface and (iii) species appearing from surface to the depth of some several ten meters. There is an inverse correlation between the depth of distribution of larvae and the degree of development of chromatophores. (3) Larvae of the dominent species are distributed at layers from surface to sub-surface layers and their zones of distribution move up with their growth. The remarkable diurnal changes of distribution of Engraulis japonica at surface layers are caused by vertical migration of larger sized larvae.
TL;DR: A histological observation of the reproductive organs of the lined shore crab, Pachygrapsus crassipes, (Grapsidae, Brachyura), known as a common crab which widely inhabits the rocky beaches of the Japanese Islands was performed in this paper.
Abstract: The present paper deals with histological observations of the reproductive organs of the lined shore crab, Pachygrapsus crassipes, (Grapsidae, Brachyura), known as a common crab which widely inhabits the rocky beaches of the Japanese Islands. The materials used were collected from the coast of Niigata City, facing the Japan Sea, and the period of collection extended from April to November, 1969. The male reproductive organ consists of six parts, and are as follows: the testis, coiled vas deferens, median vas deferens, prostate gland, ejaculatory duct, and external penis. The thicker part of the epithelium of the coiled vas deferens produces the secretory droplets, which are weakly positive to PAS reaction, and are released into the lumen. The prostate gland, consisting of many blind tubes with a simple layer of epithelium, produces secretory droplets of the spindle shape that become stained with basophilic dyes. Both types of secretory droplets reach the ejaculatory duct, and move to the basal portion of the penis together with spermatozoa. While the outer surface of the penis is coated with a chitinous layer, its epithelium constituting an inner duct is invaginated deeply into the cavity. The female reproductive organ consists of the ovary, chitinated short duct, and the seminal receptacle. In the central part of the ovary a germinal center is visible, and the oocytes develop and migrate toward the cortical region of the ovary. A simple layer of the columnar epithelium of the seminal receptacle produces the basophilic substance in colloidal form which are discharged into the lumen. The secretory function of this epithelium is more active in the virgin crab than in crabs after copulation. There could not be seen spermatophore and/or its related material anywhere in the gonoducts of this crab.
TL;DR: The pigmented zones in the test plate of a sea urchin, Strongylocentrotus intermedius, can be regarded as real annual zones or not are concluded to be the winter ring in each test plate during the active growth period in winter.
Abstract: The present study was undertaken, with the aid of tetracycline labelling, to know whether pigmented-growth zones in the test plate of a sea urchin, Strongylocentrotus intermedius, can be regarded as real annual zones or not. The urchins were reared in aquaria for fourteen months from August, 1967 to October, 1968, giving tetracycline four times at appropriate time intervals through the peristomial membrane. Pigmented-growth zones were clearly seen along the longitudinal suture of each of the test plates, while they were not clear along both the latitudinal areas of the suture and along the inner surface. In each test of the sea urchins labelled with tetracycline four times, only two bands of the tetracycline fluorescence were observed along both the longitudinal suture and the inner surface. A pigmented-growth zone was clearly observed in each test plate between these two bands of tetracycline fluorescence caused by the injection on October, 1967 and March, 1968. The pigmented zone was concluded to be the winter ring in each test plate during the active growth period in winter.
TL;DR: In this article, the addition of Lascorbic acid (AsA) and dehydro-Lascorbric acid (DAsA), after adjustment to pH 6.4 and 4.3 with sodium hydroxide respectively, to Alaska pollack brayed meat caused an increase in the strength of the gel.
Abstract: The addition of L-ascorbic acid (AsA) and dehydro-L-ascorbic acid (DAsA), after adjustment to pH 6.4 and 4.3 with sodium hydroxide respectively, to Alaska pollack brayed meat caused increase in the strength of the gel. Both AsA and DAsA had improving action on the gel strength, but DAsA was more potent than AsA. About 80% of added AsA was recovered as the reduced form in the gel when AsA was added to the brayed meat. On the other hand, about 20% of added DAsA was reduced to AsA when DAsA was added to the meat. These results suggest that the improving action of AsA in the gel formation may be due to the oxidation of sulfhydryl groups in fish proteins by DAsA. When AsA was heated with actomyosin in solution at 80°C for 20 minutes, AsA was almost completely recovered as the reduced form. On the other hand, when DAsA was heated with actomyosin at 80°C, some of it was reduced rapidly to AsA by the reaction with actomyosin during the first 5 minutes. These results suggest that DAsA may oxidize sulfhydryl groups in the actomyosin molecule.
TL;DR: The development of rancidity in fish flesh during storage at -20°C effected the subsequent decrease of protein soluble in 5% NaCl, and differences in preventive effects of phospholipids on actomyosin-caproic acid and propanal systems seemed to have originated from differentiae of caproic Acid and Propanal reaction mechanisms with actomyOSin.
Abstract: The development of rancidity in fish flesh during storage at -20°C effected the subsequent decrease of protein soluble in 5% NaCl (pH 7.0). Actomyosin (1.6-2.0mg/ml), a protein affecting the qualities of fish flesh, was reacted at pH 7.2 and ionic strength 0.5 with short chain free fatty acids or aliphatic aldehydes (3 μM/mg protein), the oxidation products of unsaturated lipids. The most reactive acid and aldehyde at -20°C were caproic acid and propanal respectively. In the presence of phospholipids (more than about 20% of total protein) insolubilization of actomyosin was prevented in caproic acid reaction medium but not in propanal one. Neutral lipids alone showed no effects on actomyosin insolubilization, while in the presence of phospholipids (over 20% of lipids) preventive effects were observed in caproic acid reaction medium. The differences in preventive effects of phospholipids on actomyosin-caproic acid and propanal systems seemed to have originated from differentiae of caproic acid and propanal reaction mechanisms with actomyosin.
TL;DR: The demonstration of duplicate loci for B-subunit isozyme of S-MDH in both species provides additional support for the tetraploidy hypothesis of salmonids.
Abstract: Supernatant malate dehydrogenase (S-MDH) isozymes of chum salmon and rainbow trout were examined by starch gel electrophoresis. Three types of B-subunit isozyme patterns were demonstrated for 396 specimens of chum salmon captured in nine rivers, and four types for 420 of rainbow trout from six hatcheries. On the bases of the occurrence of three isozymes at distinctly asymmetrical ratios in heterozygote variants and the frequencies of phenotypes in the populations examined, it was suggested that each of these two species possesses duplicate genetic loci producing dimeric isozymes, which are composed of subunits B' and B in rainbow trout, and B and B" in chum salmon, under the control of corresponding alleles. The gene frequencies of B allele in the rainbow trout populations and the frequency of B" allele in the chum salmon populations were respectively .103 and .056 at most: 65 to 95 percent of rainbow trout exhibited a single isozyme consisting of B' subunit, and more than 82 percent of chum salmon exhibited one consisting of B subunit. The demonstration of duplicate loci for B-subunit isozyme of S-MDH in both species provides additional support for the tetraploidy hypothesis of salmonids.
TL;DR: Artemia is capable of converting the dietary brassicasterol to cholesterol, and cholesteryl acetate-14C showed a constant specific activity during repeated crystallizations.
Abstract: In the present study, the bioconversion of the dietary brassicasterol in Artemia salina was investigated. After administration of the Cyclotella nana containing brassicasterol-14C to Artemia, the sterols were isolated from the tissues of Artemia. The isolated sterol was found to contain only cholesterol and to reveal relatively high radioactivity. In column chromatography on a silver nitrate-impregnated silicic acid as acetate, cholesterol-14C gave one radioactive peak corresponding to cholesteryl acetate. Moreover, cholesteryl acetate-14C showed a constant specific activity (dpm/mg) during repeated crystallizations. On the basis of these results, it was concluded that Artemia is capable of converting the dietary brassicasterol to cholesterol.