We present a stochastic model that describes the gulping behavior of fish larva to planktonic prey. The model basically deploys the Yule's process, for it conveysthe situation that the previous experience on feeding bouts is influential to the sequential volition of gulping.
Let P_x (t) indicate the probability of how larval fish gulp x prey during the time interval [0, t], and λ_x(t)w+o(w)(o(w)/w→0) the conditional probability that larval fish gulped x preys by the time t and the next gulping behavior occurs once duringthe time interval [t, t+w]. In order to characterize λ_x(t), λ_x(t)=λ_x+k (λ, k: constants) is adopted. This arrangement shows that the gulping behavior is dependent upon conditional experiences (λx)and non-conditional potential (k). Then, the differential equation system with respect to P_x(t) is solved under an initialcondition.
When λ>0, P_x(t) shapes theprobability distribution function of the negative binomial type;when λ=0, P_x(t) shapes of the Poisson's type; and when λ<0, P_x(t) shapes of the binomial type, respectively.Thus, the parameter λ may operate asan indicator which distinguishes the dietetic maneuvers of larval fish and itsramifications.

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Feeding activity was investigated for the artificially raised juvenile fish of olive flounder Paralichthys olivaceus and ocellate puffer Takifugu rubripes which incurred hunger trials for varioustime spans. They were fed brine shrimp Artemia salina nauplii programatically every 6 hours, and the time interval between two sequential gulps (GI) was monitored for abouthalf an hour. Their statistics demonstrated that the flounder's gulping pitch wassusceptible to hunger: it varied the fickle attack in the early trials to the periodic one in the late trials with the acceleration ofthe pitch. On the contrary, the puffer demonstrated a shift in mean GI that didn't correlateto the hunger persistence and stable pitch of any trials, which may mean that the puffer was under the control of someother factor than the stimulus of hunger.
The stochastic estimates on the gulping number per mean GI for each trial typified those of either binomial, Poisson's or negative binomial distribution type. The flounder indicatedthe succession from negative binomial type (via Poisson's) to binomial. The puffer, on the other hand, nearly conveys Poisson's with one exception. These lend support to the explanation between hunger persistence and the gulping mode, which isthe focus of our research.

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The nitrogen transportation within the thallus of Laminaria japonica Areschoug was investigated both in laboratory and field experiments. In the laboratory, it was observed by using ¹⁵N as a tracer that the thallus allocated labelled soluble organic N to the younger basal tissues and labelled ammonium to the mature apical tissues. In addition, the younger basal tissues had a higher NH₄⁺ uptake ratethanmature apical tissues, and the assimilation of NH₄⁺ was more active in thematuretissues.These results suggest that this transportation is based on two sourcesink relationships.One is the transport of inorganic N from basal to mature tissues for assimilation. Another is the transport of soluble organic N assimilated in mature tissues to basal meristematic tissues for growth.
To understand the transportation in the natural environment, tissue removal experiments wereconducted during N-rich (Jan-Feb) and N-poor (Apr-May) periods. During N-rich periods, the removal of the apical parts led to a decrease of total soluble N content and an increase ofinorganic N content in basal tissues and was associated with reduced growth rate. On the other hand, the removal of the basal part resulted in the reverse phenomenon to the removal of the apical part. Thus, the defined transport mechanism is closely connected with the younger basal tissues and mature apical tissues. It is suggested that the mechanism plays an important rolein the growth and survival of the blade in the natural environment. The characteristics of the N transport mechanism are also discussed.

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The age structure and seasonal changes in mortality of the sunray surf clam Mactra chinensis older than age at recruitment (3 years) were studied using data collected from April 1991 to February 1992 off Tomakomai, southwest Hokkaido, Japan. Wide fluctuations in the number of recruits of various ages were clearly observed and the estimated density of the recruits was ranged from 0.6 to 4.6 ind./m2. The highest monthly mortality of 3-7-year-old clams occurred in the fall, whereasthe mortality of those aged 8 years and older was constant throughout the year. The estimated mean annual mortality rates of 3-9-and 10-year-old clams were 42.9 and 76.0%, respectively. It was considered thatthe mortality would appear to be due to the digging out from the surface of the bottom and subsequent dispersion of the clam as a result of wave-sweep action in the fall, whereas the highmortality of clams aged 8 years and older was a result of physiological longevity. The most effective utilizationof the clam stock in this area is discussed.

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Synthetic oligonucleotides were used to identify motifs of simple repetitive sequences in cultivated laver (Porphyra yezoensis and P. tenera) genome by Southernhybridization.Three oligonucleotides, (CAC)₆, (GT)₈ and (GGAT)₄, hybridized intensely with genomic DNA, suggesting that these simple repetitive sequences were abundant and highly dispersed in the laver genome. Withthese oligonucleotides as probes, DNA fingerprinting was examined to distinguish cultivars of the laver. When genomic DNA from six cultivars were digested with Hae III or Afa I, and hybridized with oligonucleotide probes, hybridization patterns appeared to be specific for individual cultivars. In addition, these fingerprints seemed to be similar duringseveral years. These results indicate that cultivars of laver can be distinguished from each other on the basis of the polymorphic patterns of the repetitive sequences.

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We calculated the stock in number of chub mackerel Scomber japonicus in the Pacific ocean off Japan during 1970-1988 by virtual population analysis (VPA). We also calculated the number of eggs spawned by all adults from estimation of the age-dependent percapita fecundity.Japan Fisheries Agency compiles the yearly egg production estimated by plankton net survey.This project is called the egg production survey. Wecompared the yearly egg production estimated by VPA and the egg production survey. We found that the yearly egg production estimated by the egg production survey fluctuates from year to year much greater than that estimated by VPA.This result suggests that either the per capita fecundity is much smaller than we considered before or the egg production survey underestimates the yearly egg production at least when the stock is rare.We also estimate fluctuation of the natural mortality coefficient of adult and the survival rate of 0 yrold fish.

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Population structure and mortality rates of the neptune whelk Neptunea arthritica in Usu Bay, Hokkaido were estimated on the basis of seasonal changes in their age group densities. Mortality in hatchlings (0 year old) occurred gradually fromsoon after hatching through spring, with a mortality rate of about 60% during this period. Mortality rates of immature individuals (1 and 2 years old) were very low. Deaths of adults (older than 3 years old) occurred in June and July, with an estimated 76.3% of the adult population dying during this period in 1980. The age structure of the population showed the III age group occurred in the highest frequency, followed by the II age group. The 0 and _??_V age groups occurred in the lowest frequencies.The number of egg capsules per egg mass annually diminished withsubstantial reductions of the number of adults.The factors affecting mortalityand the decrease of resources were discussed.

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For better understanding of the Pacific-wide skipjack tuna Katsuwonus pelamis population structures, a series of genetic studies has been conducted. Analyses on genetic compositions of fish schools taken from the western Pacific Ocean and those from Hawaiian waters in differentseasons together with tag-recovery data aswell as size distribution in fish schools sampled madeit possible to 1) break down the central-eastern Pacific subpopulations, defined before, into at least thethree subpopulations genetically distinct each other: the central-west Pacific, the central-northeast Pacific, and the centralsoutheast Pacific subpopulations and to 2) delineate the range and the routes ofmigration of the central-west Pacific subpopulation.In addition, comparisons of the genetic data from Hawaiian waters and those from the other regions of the central Pacific and the eastern Pacific Ocean suggested necessity of further genetic work for more clear delineation of population structures as wellas their migratory routes there.
On the basis of the observations and the analyses conducted, a set of probable mechanisms of subpopulation differentiation was proposed to be considered for thesake of future works.

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The autonomic nervous system innervating the stomach and ovaries of the Nile tilapia Oreochromis niloticus was studied in combination with neuroanatomical, fluorescent and electron microscopic, and retrograde-labeling methods. An anatomical examination revealed that the vagal nerve arose from the medulla oblongata and reached the stomach, as a parasympathetic innervation.Several nerves were branched off from the main vagal trunk behind the transverse septum, and one of them reached ipsilaterally at the anterior ovary. The vagal sympathetic and the 3-4 sympathetic ganglion cells, and the parasympathetic ganglion cells in the vagus nerve were involved in autonomic innervation to the two organs. By fluorescent microscopy combined with a formaldehyde-glutaraldehyde method, it was demonstrated that the adrenergic nerve fibers existed in both nerves innervating the stomach and ovaries. Electron microscopic observation revealed that cholinergic and adrenergic types of synaptic vesicles were contained in both nerves, in addition to a few larger vesicles assumed to be peptidergic.Neural origin of the innervation to the stomach was traced to the medulla oblongata, the vagal sympathetic ganglion and the 3-4 sympathetic ganglion by retrograde labeling with cobaltous lysine complex. On the other hand, distribution of the postganglionic cells innervating the ovaries was restricted to the 3-4 sympathetic ganglion, while the origins of the parasympathetic innervation were still obscure.

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HCc is a major basic nuclear protein of Crypthecodinium cohnii (Dinophyceae). Inorder to elucidate the gene organization of HCcl gene, it was amplified by PCR methods using the total DNA as atemplate and the nucleotide sequences of HCcl gene and its flanking regions wereestablished. Theresults were as follows: [1] HCcl gene was composed of multiple copies and arranged in tandem; [2] itcontained 4 introns lacking the GT-AG consensus sequences, which are conserved inother eukaryoticintrons; and [3] eukaryotic promoter consensus sequences such as TATA box or CAAT box were not observed in the flanking regions of HCcl gene. An interesting pointis whether such atypical-eukaryotic features of the HCcl gene organization are common in dinoflagellates or not.

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The laboratory stock culture of Chattonella marina harbors several bacterial stains and has been surviving in hundred times of transfer process. As predominant bacteria, Alteromonas, Flexibacter and Pseudomonas spp. were isolated from a non-axenic culture of C. marina. In the stateof mixed cultures of an axenic algal strain with co-existent bacterial isolates, the living algal cells were maintained over 30 days after transferred to enrichment sea water (ESS) medium. On the other hand, algal cells began to decrease at 10 days and were not detected at 30 days at all inaxenic cultures. On the addition of enrichment solution (ESP) into axenic cultures, algal cells were stimulated to grow evenafter reached maximum growth. When above 100mg/l of polypepton was added to non-axenic cultures, the algal cellcounts decreased as the total bacterialcounts increased. If the supernatant solutionsof co-existent bacterial cultures incubated in nutrient rich media (ZE-CI) were added to algal axenic cultures, algalcells were completely killed in above 5% concentrations within 7 days incubation.

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Pointhead flounder, Hippoglossides pinetorum, taken by commercial gillnets and an experimental beam trawl net in Ishikari Bay, Hokkaido from September 1991 to July 1993 were aged using polished otoliths (saggitae). Ages were validated by the monthly change in the percentageof otolith with translucent edge and marginal increments; a single opaque and translucent zone was formed annually. The regression method and Lee (Fraser-Lee)'s method were used to estimate the back-calculated length. Growth of pointhead flounder was expressed as L_t=251.9(1-exp^{-0.261(t-0.142)}) formales and L_t=315.1(1-exp^{-0.219(t-0.200)}) for females using back-calculated lengths by the regression method and L_t=251.6(1-exp^{-0.263(t-0.142)}) for males and L_t=333.0(1-exp^{-0.204(t-0.186)}) for females using back-calculated lengths by Lee's method, where Lt is the standard length (mm) at estimatedage t. Small differences in the theoretical lengths of older female fish were found between the twomethods. However, the theoretical standard lengths predicted by the two methods were very similar at most estimated ages and indicated the approximate actual length at each age.

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The reproductive behavior of Pacific cod (Gadus macrocephalus) was examined durincaptive experiments. The captive cod spawned demersal and slightly adhesive eggs, which dispersed and settled onthe tank bottom.Ripe males and females did not display the ventral mounting behavior typically displayed in other gadid fishes during spawning. Neither sound production nor aggressive behavior occurred during the breeding period. The female released approximately all of her ripe eggs in a singlespawning, which lasted less than 20 seconds. Spawning involved one female and one or more males inmidwater of the tank. Just after release of eggs by a female, one or a few males followed the female andspread sperm on the eggs using tail beats. The eggs and milt slowly sank to the bottom.
The spawning behavior of Pacific cod differed from the single-pair spawning characterized by ventral mountingand multiple spawning over a several day period seen in walleye pollock and Atlanticgadid species.

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The rateof movement, recovery, correlations between markers and nutrients were determinedinprawn Penaeus japonicus using inert markers, chromic oxide and 5α-cholestane. The mean retentiontimes of cholestane and chromic oxide in the gastro-intestinal tract were 14.5 hand 7.2 h, respectively. This result suggested a different rate of movement of the two markers in the gastro-intestinal tract of prawns. There was a significant correlation (r=0.97) between the fecal cholestane and cholesterol contents. Cholestane also showed a high recovery and low absorption in the prawn body.These results of the present study indicated that cholestane is superior to chromic oxide as lipid digestibility marker in P. japonicus.

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A biosensor system is described for the rapid determination of cell number of Enterococcus seriolicida in a biological sample. The system consisted of E. seriolicida immobilized on a membrane, Clark-type oxygen electrode, and STAN-P culture medium.The STAN-P medium consisted of sodium
azide, a bacterial inhibitor which suppressed the growth of most microorganisms, but not E. seriolicida. The number of E. seriolicida organisms was determined by measuring the oxygen consumption of the cells with an oxygen electrode. The optimum conditions for carrying out the preparation of microorganisms were as follows: incubation temperature, 37°; incubation time, 1 hr, and concentration of sodium aside, 0.3g/l. A linear relationship was obtained between the output current of the sensor and
the number of E. seriolicida cells, which ranged from 1.4×10⁷-7.2×10⁷ cells/ml. The time required for
a single assay, including the preparation of microorganisms, was 2 hr.

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Niboshi (boiled and dried anchovy) was prepared from fatty and lean raw materias, pulverized, packed in a plastic pouch with and without an oxygen absorber, then stored at 25nd-20°C for 60 days. Lipid oxidation and changes in the free amino acid compositions of the pulverized niboshi duringstorage, were investigated.
In the fatty samples, lipid oxidation and brown discoloration significantly occurred during storage at 25°C. At the same time, the contents of the free amino acids such as taurine, glutamine, methionine, histidine, and lysine decreased. In contrast, in the lean sample, lipid oxidation and brown discolorationonly slightly occurred during storage at 25°C. The taurine content remained unchanged during storage.When packed with an oxygen absorber, both the fatty and lean samples were effectively protected fromlipid oxidation during storage, though a brown discoloration developed with decreases in the glutamine and histidine contents. In the case of storage at -20°C, lipid oxidation in both the fatty and lean samples proceeded gradually. However, the brown discoloration was not observed throughout the 60-daystorage.
From these results, it was presumed that methionine was decomposed by the action of the lipidperoxides, histidine, lysine, and taurine that reacted with the carbonyl compoundsproduced during the course of oxidative degradation of the lipids to form brown pigments, while glutamine decreased at room temperature.

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Feeding experiments were conducted to determine the requirements of early juvenile red sea bream (Pagrus major) for eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA)by feeding Artemia nauplii containing different levels of EPA or DHA for 12 days. Juveniles fed EPA-enriched Artemia had a high survival rate but very poor vitality, while those fed on Artemia enriched with DHA had both a high survival rate and vitality. The vitality of fish was effectively improved by elevation of DHA levels in Artemia. In the DHA-enriched Artemia, the EPA content increased from the initial value together with the appearance of docosapentaenoic acid (DPA), indicating retroconversion from DHA to EPA through DPA in the nauplii. The requirement of early juvenile red sea bream for DHA was estiated to be 0.95-1.62% in Artemia on a dry matter basis when vitality was used as an index, and was satisfied with 2.25% EPA or 0.95% DHA (2.05% n-3 HUFA) on a dry basis when basedon the survival rate.

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White croaker and walleye pollack frozen surimis containing different amounts of Ca were manufactured through processing with CaCl₂-washing, and gel-forming ability andcryostability were then investigated by measuring the myofibrillar Ca-ATPase activity, textural parameters of heat-induced gels and their protein subunit composition.
Although thse breaking strain of heatinduced gels noticeably decreased by Ca²⁺ permeated into the meat, the breaking strength increased markedly with an increase in the Ca content. An excellent gel texture was obtained in the frozen surimis containing about 5 mmol/kg of Ca.
The improved gel-forming ability and the myofibrillar Ca-ATPase activity hardly changed for 12 months at -30°C when frozen surimi contained less than 5 mmol/kg of Ca, but the frozen shelf-life was diminished when more than 12 mmol/kg of Ca was contained.

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Some osmerid fishes are known to produce glycerol in winter to protect against freezing. One such species, the rainbow smelt Osmerus mordax, was acclimated to low temperatures to elucidate the glycerol-producing mechanism. When non-glycerol-producing fall-caught smelt were acclimated to +1 and -1°C in the absence of feeding, both groups synthesized large amounts of glycerol. Liver and muscle glycogen levels were low in both groups, and were also lower in the-1°C group than in the +1°C group, suggesting that glycogen was a source of glycerol. A similar result was obtained with acclimation of winter-caught smelt to +1 and -1°C. Glycogen levels in summer- and winter-acclimatized surfsmelt Hypomesus pretiosus also indicated a high glycogen demand in winter. Triglycerides did not appear to be a source of glycerol, as triglyceride levels in both species did not show an inverse relationship with glycerol levels. Because glycerol levels remained relatively high in the acclimated rainbow smelt despite a considerable glycerol efflux and low glycogen levels, glycogen does not appear to be the only source of glycerol in these fishes.

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The arsenic metabolism in fish was examined using carp Cyprinus carpio and five arsenic compounds (arsenate, dimethylarsinate, arsenobetaine, trimethylarsine oxide, and arsenocholine). In order
to avoid the bacterial action in the gut tract suggested previously, the arsenic compounds were administered to the fish not orally but intraperitoneally. Low retention of arsenicby the fish was observed after administration of arsenate, dimethylarsinate, or trimethylarsine oxide, while the arsenic administered as either arsenobetaine or arsenocholine was highly retained.After extraction and partial purification by Dowex 50 column chromatography, arsenic compounds accumulated inviscera and muscle were analyzed by HPLC-ICP / AES.As a result, arsenate and arsenocholine were found to be converted to arsenite and arsenobetaine, respectively, within the fish. Conversion of trimethylarsine oxide to another compound (probably dimethylarsinate) was also observed. In contrast, no biotransforma-tion of dimethylarsinate and arsenobetaine occurred.

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Non-destructive phosphorus-31 nuclear magnetic resonance (³¹P NMR) with a surface coil attachment was used to evaluate the effects of cold-CO₂ anesthesia on the energy statein carp muscle reflecting the metabolic changes of high energy phosphate compounds, inorganic phosphate (Pi), and intracellular pH (pHi). The levels of creatine phosphate (PCr), ATP, and pHi in the carpmuscle were lowered by cold-CO₂ anesthesia compared with those in the muscle of unanesthetized carp. The carp anesthetized with cold-CO₂ seemed to be in a different metabolic state. ³¹P NMR with a surface coil was also used to evaluate the degree of freshness of carp muscle block stored over a 24 hperiod postmortem. The ratios of [PCr]/[Pi] and [ATP]/[Pi] and the pHi decreased rapidly and continuously during the acceptable stage, and were demonstrated to be potential indices to estimate the freshness of carp muscle. ³¹P NMR is a powerful tool for the evaluation of freshness, because of its non-invasive, convenient, rapid, and simultaneous determination of high energy phosphate compounds, Pi, and pHi in the carp muscle.

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Alcohol dehydrogenase (EC 1. 1. 1. 1) in skipjack liver was extracted with sodium phosphate buffer solution and purified by ammonium sulfate fractionation and chromatographies on Toyopearl HW-55F, Butyl-Toyopearl 650M, and Blue-Toyopearl 650 ML. At the final step, it was separated into two fractions (ADH-1 and ADH-2). By this method, a final specific activity (ADH-1) of 590 units/mg and purification of 118.0-fold was attained. With respect to ADH-2, a final specificactivity of 1063 units/mg and purification of 212.6-fold was achieved. The apparent molecular weights were estimated to be about 140, 000 (ADH-1) and 130, 000 (ADH-2) by gel filtration on Toyopearl HW-55F. ADH-1 gave a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis which also revealed that this enzyme was composed of identical subunits with a molecular weight of 33, 000. ADH-2 showed a single band with MW of 66, 000. In relation to ADH-2, the optimum temperature was about 40°C. ADH-2 was stable at 30°C for 30min but completely inactivated at 40°C for 30min. The optimum pH was about 10 and ADH-2 was stable at pH 7-9 but was unstable when the pH was lower than 7.0. ADH-2 was activated by Co²⁺ and Mn²⁺, but was inhibited by Hg²⁺, Zn²⁺, and Cu²⁺.

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Digestible crude protein (DCP) of feeds could be calculated based on the DCP content of the feed components determined at different water temperatures with various sizes of fish. This was verified in Experiment I with rainbow trout, carp, tilapia and ayu, and the DCP values were almost similar for the different sizes of a particular fish. The effect of temperature on DCP values ofanimal protein sources differed among the species; the influence was not prominent for white fish meal and local fish meal, whereas a dependence was noted in the case of carp and tilapia for meat meal, and rainbow trout and ayu for silk worm pupa meal. Among the plant protein sources, the DCP values were dependent on fish species as well as temperature in the case of corn gluten meal and rice bran, but only on fish species in the case of soybean meal and wheat flour. The digestibility of the protein feedstuffs were highest at 15°C for rainbow trout, 25°C for carp and tilapia, and 20°C for ayu. In Experiment II, it was found that the DCP values calculated on the basis of DCP of each feedstuff were similar to those practically determined, suggesting that the DCP of diets could be calculated if the composition of the diet is known.

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Methanol extracts were prepared from the abdominal muscles of Japanese spiny andshovel-nosed lobsters and free amino acids, ATP related compounds, betaines, and other components in the extracts were analyzed. The two lobsters were rich in glycine, arginine, glycine betaine, trimethylamine oxide, glutamine, taurine, homarine, proline, alanine, ADP, Na⁺, K⁺, PO₄^3-, and Cl^-. Glycine, arginine, proline, alanine, glutamic acid, glycine betaine, trimethylamine oxide, AMP, IMP, NaCl, KCl, and KH₂PO₄. They were confirmed to be taste-active for the Japanese spiny lobster taste by the sensory taste test. As for shovelnosed lobster, valine, isoleucine, leucine, sarcosine, and methionine were tasteactive in addition to theabove 11 components except IMP.

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The energy values of fish feed could be a suitable indicator for choosing an appropriate diet for a particular species. This study examined the effect of fish size, water temperature and time of feces collection on energy digestibility. Inaddition, energy digestibilities of practical diets and commercial feeds were determined to find out if digestible energy (DE) values could be calculated from grossenergy (GE) values.
The DE determinations should preferably be conducted on carp weighing about 10 gmaintained at around 20°C and with rainbow trout weighing less than 100g at a water temperature between 10-15°C.The digestibility of energy increased in proportion to the lapse of time of fecal collection, until about 18h in rainbow trout and even beyond that in carp, due to the leaching ofnutrients.It was also confirmed that there was no change in the energy digestibility of fish over time.
Comparing the energy digestibility of practical and commercial diets for carp, itwas found that the average figure was 80%, proving that the DE of diets could be estimated from the GE values.

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The free amino acids responsible for the browning of scallop adductor muscle during the cooking process were investigated. Perchloric acid extracts of unfrozen muscle immediately after death, which did not show browning, and those of cold-stored muscle and of frozen-and-thawed muscle, which showed strong browning, were cooked at 110°C for 90min, then the contents of amino acids in these extracts before and after cooking were determined with HPLC. Scallop adductor muscle contained large amounts of glycine (1600-1900mg/100g), taurine (700-1000mg/100g), arginine(500-700mg/100g) and alanine (100-300mg/100g). The total amount of these four amino acids accounted for more than 90% of the total amount of free amino acids in scallop adductor muscle.
After 3 days storage at 5°C, alanine and glutamic acid increased, and arginine as well as proline decreased. During freezing-and-thawing glycine and alanine increased, and proline decreased. The extract from unfrozen muscle immediately after death did not show changes in contents of free amino acids after cooking, and those from cold-stored muscle and frozen-and-thawed muscle showed a decrease in the contents of taurine (10-20%) and alanine (25%). Thus, taurine and alanine are thought to be the main amino acids responsible for the browning of cooked scallop adductor muscle.

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The extract of the soft coral Lobophytum variatum agglutinated horse erythrocytes but not human ABO or rabbit erythrocytes in the presense of calcium ions. The activity was inhibited by mucin Type I from the bovine submaxillary gland and also by simple sugars such as D-ribose and N-acetylneuraminic acid. Two lectins, LVL-1 and LVL-2, were purified by gel filtration on Sepharose 4 B succeeded by ionexchange chromatography on Mono-Q. Both lectins were glycoproteins composed of covalently bonded subunits of 53 kDa. The sequence of the amino-terminal region of LVL-1 was determined as Ala-Ile-Asn-Gln-Ser-Ser-Gly-Asn-Leu-(X)-Asp-Arg-Leu-Gln-Glu-Arg-Phe-(X)-Leu-Asp-His-, where X is anunidentified residue.

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A study was made of the effect of drug-metabolizing enzyme activity induced by polychlorinated biphenyl (PCB) on the residence time of quinoline antibacterial agents in carp Cyprinus carpio. Carp were fed with a diet containing PCB (1mg PCB/kg body weight/day) for 2 weeks toinduce drugmetabolizing enzymes. After pretreatment, three kinds of quinoline antibacterialagents (oxolinic acid, piromidic acid and nalidixic acid) were individually administered in feed to PCB-treated or nontreated (as control) fish as a single dose of 20mg/ kg body weight. The peak concentrations of oxolinic acid in the blood, liver and muscle of PCB-treated fish were lower than half of those inthe control. The concentrations of piromidic acid in the liver, muscle and kidney of PCB-treated fish were undetectable throughout the experiment (2 to 98 h post dosing), except in the blood. However, the residence time and concentration of nalidixic acid in the tissues of PCB-treated fish showed nosignificant difference comnared with those in the control.

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Actin denaturation upon ATP or pyrophosphate (PPi) addition has been studied in carp myofibril dissolved in 0.5M KCl. ATP-treatment of myofibril remarkably decreased its Mg-ATPase activity with no loss of Ca-ATPase activity. The treated myofibril has a quick inactivation phase in its Ca-ATPase inactivation profile. ATP dissociated myosin from actin. These are all reproduced also by PPi. PPi-induced actin denaturation in the myofibril involves PPi-induced actin dissociation from myosin and a subsequent denaturation of dissociated actin by 0.5 M KCl present in the medium. Ammonium sulfate as high as 1.75M causes no actin denaturation. It was concluded, therefore, that actin is protected from KC1 (or NaCl)-induced denaturation by binding to myosin.

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Chopped and homogenized tissues of oyster were stored in the presence of an antibiotic chloramphenicol (CP) and the postmortem changes of ATP and its related compounds were investigated to clarify the role of endogenous enzymes and bacterial enzymes on these changes. With and without CP, the degradation of ATP to inosine (HxR) in the homogenized adductor muscle, mantle, and gill, or to xanthine (Xt) in the homogenized body trunk proceeded smoothly. Therefore, the breakdown of ATP to HxR or Xt was mainly caused by endogenous enzymes. When the tissue structure is maintained in the chopped tissues, ATP-breakdown by the endogenous enzymes was limited from ATP to IMP in the adductor muscle or to AMP in other tissues and further breakdown proceeded slowly. In the chopped and homogenized tissues, the decrease of IMP and HxR and the increase of hypoxanthine and Xt during the decomposition stage were suppressed at certain levels in the presence of CP. These changes were supposed to be mainly due to the exogenous enzymes.

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