A study of European hake Merluccius merluccius gill net selectivity was undertaken off the Algarve (Southern Portugal), between 1999 and 2001. Four nominal mesh sizes (70, 80, 90 and 100 mm) were used in fishing trials and the ‘share each length class catch total’ (SELECT) method was used to fit gill net selectivity curves. Hake were caught in the same size range by all mesh sizes, between 17 and 65 cm total length. While most fishes were wedged, significant and similar proportions were entangled in all mesh sizes, contributing to the wide size range, and in some cases, bimodal shape of catch size frequency distributions. Insignificant numbers of undersized hake were caught, with most catches consisting of mature female fish. Catch rates decreased sharply with increasing mesh size. The bimodal model gave the best fit for hake that were wedged, with estimated modal lengths of 40.1, 46.7 and 51.0 cm for the 70, 80 and 90 mm nominal mesh sizes, respectively. The high catch per unit effort of the smallest mesh size, with most fish caught being female, together with the fact that the modal length of the fitted selectivity curve is well below the size at maturity for hake in Portuguese waters, suggests that the 80 mm nominal mesh size is more appropriate for ensuring resource sustainability.

View full abstract

The inheritance mode of six previously published and newly developed microsatellite markers was investigated in newly hatched Haliotis discus hannai larvae from four controlled crosses, and the feasibility of these markers for kinship estimation was also examined. Microsatellite DNA was successfully amplified from H. discus hannai larvae using the Chelex extraction method, and at least 15 microsatellite loci could be analyzed in a single trochophore larva. All six microsatellite loci were compatible with Mendelian inheritance. Neither evidence of sex-linked barriers to transmission nor evidence of major barriers to fertilization between gametes from the parents was shown. One of the six microsatellite loci showed the existence of null alleles in one family, indicating that the loci should be used in population studies with caution. Although the null allele heterozygotes were considered as homozygotes in the calculation of genetic distance, offspring from four full-sib families were unambiguously discriminated in the neighbor-joining dendrogram. The result demonstrates that the microsatellite markers might be capable of discriminating between related and unrelated abalone larvae in the situation where no pedigree information is available.

View full abstract

The present study was designed to estimate the critical light intensity required for growth of Zostera marina and that which determines its depth limit. Seeds of Z. marina collected at Matsunase, Ise Bay, Mie Prefecture, central Japan were germinated and grown to young plants of 10 cm in length. The young Z. marina were cultured for 1 week in various water temperatures, and their photosynthesis and respiration were measured under various photon irradiances. The daily compensation point was estimated by a mathematical model based on photosynthetic activity and diurnal changes in solar irradiance. The estimated daily compensation point of young Z. marina was 5.7% of sea surface. The depth limit was determined by the Beer-Lambert law concerning the relative solar irradiance on the sea surface and the extinction coefficient. Almost all previous studies report a shallower growing depth of Z. marina than the present result, but the lowest reported data agreed well with the current estimated depth limit. Therefore, the mathematical model in the present study can estimate the production and critical growing depth of Z. marina. The results suggest that the compensation depth is controlled mainly by the solar irradiance reaching the Z. marina beds.

View full abstract

Four highly variable microsatellite loci, Acs1*, Acs3*, Acs4* and Acs9*, were isolated and then used to investigate genetic diversity and population structure in black sea bream, Acanthopagrus schlegeli, collected from wild populations of six locations (western Japan and southern Korea), and hatchery stock and post-stock populations from Hiroshima Bay. When allelic segregation of each microsatellite locus was examined using the single spawning pair and their progeny, all loci were well fitted to the Mendelian manner of inheritance. The genetic variations at these loci in the eight populations revealed high levels of variability. In the wild populations the mean number of alleles per locus was 10.8-13.5, and the mean observed hetrozygosity was 0.755-0.828. In contrast, these values in hatchery stock population were 10.0 and 0.776, respectively. Genetic distance indicates the existence of geographic divergence between western Japan and south Korea, and little genetic differentiation among populations in western Japan.

View full abstract

The development of escape behavior from moon jellyfish Aurelia aurita was studied in the red sea bream Pagrus major larvae raised with two distinct dietary regimes: one fed rotifers and Artemia nauplii enriched with highly unsaturated fatty acids (the HUFA-enriched group); and the other fed those without enrichment (the HUFA-deficient group). The length of time that it took for a larva to be captured by three medusae of A. aurita was measured. The observation was continued for 5 min. The capture time was compared between the two dietary groups for the same age, and among different ages within the same dietary group. The capture time in the HUFA-enriched group was significantly longer on day 18 and day 20 compared to the younger stages, whereas there was no such discernible developmental changes in the HUFA-deficient group. The average capture time on day 18 in the HUFA-enriched and HUFA-deficient groups was 277 and 161 s, respectively, with almost the same body length (7.1 mm and 7.2 mm, respectively). Fatty acid analysis revealed that rotifers and Artemia in the HUFA-enriched group contained 2.2 and 0.6% of docosahexaenoic acid (DHA) in dry weight, whereas those in the HUFA-deficient group did not contain any detectable amount of DHA. Present work revealed that A. aurita can be a potential predator of P. major up to lengths of 7.1 mm (day 18) when the nutritional condition of the fish was good, and that the threat can be serious up to larger sizes when the fish had experienced inferior dietary conditions.

View full abstract

The gonadal development and serum profiles of vitellogenin and sex steroids in rearing Sebastes schlegeli were monitored for one full year. Female fish began vitellogenesis from November and completed it in March. Gestation occurred from April, and parturition occurred in June. A thin chorion and scanty cortical alveoli are oogenetic peculiarities of this fish. Male fish began spermatogenesis from June, and matured in November and December. It appears that copulation occurs in November and December, and that the sperm are stored freely in the ovary during the early vitellogenic period and under the ovigerous lamellae epithelium during the late vitellogenic period. Serum vitellogenin levels in female fish had a good correlation with oocyte growth. Serum estradiol-17β (E2) levels in female fish were elevated from November to February, suggesting that E2 controls vitellogenesis. Serum 17, 20β-dihydroxy-4-pregnen-3-one (DHP) in female fish increased in the late vitellogenic period, suggesting that DHP was a maturation-inducing steroid. High levels of serum DHP during gestation suggest that it may be one of the endocrine factors for maintaining gestation. Serum 11-ketotestosterone (11-KT) levels in male fish were elevated from June to October, suggesting that 11-KT controls spermatogenesis. Serum DHP in male fish had a single peak in October, suggesting that DHP plays some role in the late stages of spermatogenesis.

View full abstract

The purpose of the present paper was to investigate the proliferation of rod photoreceptor cells in the retina of Japanese eel, elvers from the coastal sea, adults from the river, and migrating adults from the ocean by means of histological and immunocytochemical methods. An increase was found in the ratio between the total nuclear number in the outer nuclear layer and the number of cone cells, and an increase in the number of rod outer segment layers (including inner segments). Using proliferating cell nuclear antigen-immunocytochemistry labeled cells were observed in the outer and inner nuclear layers in adult eel from the river. These results suggest that rod photoreceptor cells proliferate in the eel retina throughout its life history.

View full abstract

Opsonization is a crucial function of the complement system in immune clearance. To identify receptors responsible for the complement-mediated opsonization in teleost, head kidney leukocytes from β-1, 3-glucan-injected and non-injected common carp (Cyprinus carpio) were subjected to a rosette-forming assay with fixed sheep erythrocytes (E^f). Leukocyte fractions rich in granulocytes and macrophages from the glucan-injected carp had an ability to form the rosette with complement-coated E^f but the corresponding fractions from non-injected fish did not, suggesting that β-1, 3-glucan elicits expression of complement receptors on those cells. While sensitization of E^f with antibodies slightly elevated the rosette formation, complement-coated E^f showed a significant increase in rosette formation and this formation was inhibited with anti-carp C3. Rosette formation was also inhibited by EDTA but not by EGTA. These results suggest that complement-dependent opsonization in carp is mediated by C3-receptors analogous to mammalian complement receptor type 3 (CD11b/CD18 or integrin α_M/β₂), which recognizes the iC3b fragment in a divalent cation-dependent manner.

View full abstract

During the period of oxygen depletion in bottom waters of Mikawa Bay of Japan in 1998 and 1999, the mortality and the glycogen content were examined for the Manila clam Ruditapes philippinarum kept in stainless-steel cages in the bottom sediment of shallow waters. In two ex-periments conducted over 5 weeks and 6 weeks, respectively, no large increase in the cumulative mortality rate was found in the early phase despite the development of oxygen-deficient waters. With further deterioration in oxygen condition, however, the cumulative mortality rate reached 99% and 57% in the first and second experiment, respectively. The mean values of glycogen content were initially 41.7 mg/g and 39.6 mg/g, and were reduced significantly to 21.4 and 15.7 mg/g, respectively, at the end of the experiments. Ruditapes philippinarum kept in normoxic waters as a control did not show a large increase in mortality rate, nor a significant decrease in glycogen content. Thus, glycogen content seems to be an indicator of physiological condition of R. philippinarum exposed to oxygen-deficient waters.

View full abstract

A two-compartment one-toxin model was fitted to data of the toxin level of Pacific oysters contaminated by Alexandrium tamarense in Hiroshima Bay, Japan. The model contained state variables for the viscera and non-viscera components of the oyster and was run using data for A. tamarense cell numbers with and without water temperature. It was tuned against toxicity data collected for the oyster. The fit of the predicted oyster toxicity to real data was best when there was no temperature link to cellular toxicity. Risk-assessment analysis suggests that the present model provides a robust indicator of the toxic status of the Pacific oyster in Hiroshima Bay. The model prediction of the toxin levels with routine monitoring of the toxic phytoplankton cell number could complement the monitoring of the toxin levels in shellfish by currently used time-consuming bioassays.

View full abstract

Development of gut microflora in abalone Haliotis discus hannai cultured at two abalone farms in Japan was similar: (i) gut microflora of juvenile abalones fed on microalgae matched microflora cultured from seawater; and (ii) gut microflora changed coincident with the abalone switching food sources from microalgae to algal pellets. After abalone reached 4 months of age, the gut microflora was replaced by algal polysaccharide-degrading bacteria, which were almost entirely characterized as facultative anaerobes. Dominant species were alginolytic, non-motile fermenters (NMF) and Vibrio spp. The gut microflora seemed to be stable in abalone older than 1 year, with NMF bacteria dominating. Ninety-six percent of the NMF isolates were identified as Vibrio halioticoli by species-specific identification using the colony hybridization method. These results show that abalone H. discus hannai has a unique developmental process in which gut microflora shifts to alginate-degrading bacteria, especially V. halioticoli.

View full abstract

A recently developed motion detector (acceleration data-logger), based on acceleration measurements, was used to monitor the swimming behavior of two free-swimming captive rainbow trout Oncorhynchus mykiss in an aquaculture net cage. Depth, swimming speeds and two-direction acceleration data were collected continuously for approximately 20 h per fish. To define relationships between swaying acceleration profiles and tail beat activity of rainbow trout, the tail beat activity of trout was monitored using a video camera in a small tank with the simultaneous use of the acceleration data-logger. During steady swimming, there were sharp, distinct peaks of swaying acceleration. When compared with the data from the video camera, the frequency of swaying acceleration was synchronized with the sequences of swimming activity. In addition, the tail beat frequency of the fish could be identified within the cycle of swaying acceleration during steady swimming phases. Mean tail beat frequency was 1.27±0.40 and 1.40±0.5 Hz (mean±SD). Using the relationship between tail beat frequency and swimming speed, the ‘preferred’ swimming speed of trout was estimated to be between 0.48 and 0.58 body length (BL)/s, and trout rarely swam in excess of 2.0 BL/s. The present study shows that acceleration data-loggers used to record spontaneous measurements of swimming speed and tail beat activity represent a useful and reliable system for accurately estimating both the rate of activities and movements of free-ranging fish.

View full abstract

The histology of the gill structure of Caprella (Amphipoda: Caprellidea) (i.e. C. danilevskii, C. subinermis, C. penantis R-type and C. verrucosa) collected from the Sargassum community of north-eastern Japan, was observed under transmission electron microscopy. The epithelial gill cells of C. danilevskii, C. subinermis, and C. verrucosa were composed of a well-developed apical infolding system (AIS) and basolateral infolding system (BIS) associated with a large number of mitochondria, whereas those of C. penantis R-type, which possessed large, leaf-like gills with distinct pillar structures, had weakly developed AIS and BIS. Experiments on the salinity tolerance of the four species of Caprella indicated that the median lethal concentration (LC₅₀) of the four species at 20°C ranged from 12.97 to 18.84 practical salinity unit (p. s. u.) with survival rates greater than 80% in salinity conditions over 25.37 p. s. u. even on day 5. The characteristics of the gills and the wide salinity tolerance of Caprella spp. indicate that Caprella spp. inhabiting the Sargassum community are euryhaline marine organisms.

View full abstract

Polymerase chain reaction (PCR) products were obtained when the total RNA prepared from the axenically cultured cells of Pseudo-nitzschia multiseries was amplified by using primers that were designed from the 16S ribosomal RNA (rRNA) region of a bacterium isolated from the cells of Alexandrium tamarense, although the amount of the products was low. Some sequences of the PCR products were identical to those of bacteria that were isolated from the cultured medium of the original nonaxenic culture of Pseudo-nitzschia multiseries strain. These results suggest that P. multiseries possesses intracellular bacteria that originate from the environmental water.

View full abstract

Changes in the levels of serum steroids and ovarian steroidogenic enzyme mRNA were analyzed in Japanese eel Anguilla japonica induced to undergo oogenesis by chum salmon pituitary homogenate (SPH) treatment. Serum 17α-hydroxyprogesterone, 17α, 20β-dihydroxy-4-pregnen-3-one, androstenedione and estrone levels were barely or not detectable during artificial maturation. In contrast, serum estradiol-17β (E₂) and testosterone (T) levels increased after SPH injections and peaked at the migratory nucleus (MN) stage. 3β-Hydroxysteroid dehydrogenase mRNA levels did not change between eels in different stages of oogenesis. mRNA levels of P450 cholesterol side-chain cleavage (P450scc), P450 17α-hydroxylase/C_17-20 lyase (P450c17), 17β-hydroxysteroid dehydrogenase type I (17β-HSD-I) and P450 aromatase (P450arom) were low before SPH injections. P450scc, P450c17 and 17β-HSD-I transcript abundance increased after SPH treatment and peaked at the MN stage. P450arom mRNA levels, however, peaked at the mid-vitellogenic stage and slightly decreased towards the MN stage. We suggest that these increases in P450scc and P450c17 mRNA levels may account for high T levels at the MN stage. In turn, the high T levels may permit the production of E₂ in spite of low P450arom mRNA levels towards the end of oogenesis. Steroidogenesis in artificially maturing eels appears to proceed unlike that in other teleosts, but whether or not this is an artifact remains as yet unknown.

View full abstract

The consumption of bluegill by Far Eastern catfish and largemouth bass was examined in aquaria. Twenty or more live bluegill were introduced into each aquarium with one catfish or largemouth bass. Bluegill were captured in Lake Sugawa, Nagano Prefecture, and almost all of them could be preyed upon by the catfish and bass. The consumption of bluegill was correlated with the body weight of catfish and bass except for the very large predator individuals. Far Eastern catfish consumed comparatively more bluegill (9.4% of the catfish body weight per day) than largemouth bass (4.5%). Stocking Far Eastern catfish is potentially an effective method for reducing bluegill, although prey-selection experiments using bluegill, native Japanese prey fish and the catfish are required before actively advocating the biological control of bluegill using Far Eastern catfish.

View full abstract

In the present study, the relationship of ovarian development and marsupial development to the female molt cycle was examined in Acanthomysis robusta (Crustacea: Mysida). Yolk accumulation in ovaries started at stage C and advanced during stages D₀-D₂ of the female molt cycle. As females at stages A-B exhibited newly spawned eggs in their marsupia and non-developed ovaries, oviposition likely occurred at stage A of the molt cycle. Larvae in the marsupia were at the egg-shaped embryonic stage during the female molt stages A-C. Larval hatching occurred at stage C, and the larvae were at the nauplioid stage during stages C-D₁ of the female molt cycle. Larvae at the postnauplioid phase appeared at stage D₁, indicating that naupliar molting occurred in stages D₀-D₁ of the female molt cycle. At stage D₂, empty marsupia were observed, and any remaining brood were at the postnauplioid phase, suggesting that young are released at stage D₂ of the female molt cycle. The brood size (8-53 embryos and larvae) was significantly correlated to female carapace length. These results indicate that ovarian development and marsupial development are closely related to the female molt cycle of A. robusta.

View full abstract

To determine the effect of vitamins C and E on lipid metabolism and interactions between them, L-ascorbyl-2-monophosphate-Mg (APM) and α-tocopherol acetate (TA) were fortified to a commercially based diet and fed to 0-year red sea bream Pagrus major and 1-year black sea bream Acanthopagrus schlegeli. Fortification of APM and TA, respectively, increased ascorbate (ASC) and α-tocopherol (α-Toc) contents in the organs. In addition, APM fortification increased α-Toc accumulation in both fishes, although TA fortification did not significantly affect the ASC content. Fortification of APM caused a depression in lipid accumulation in the intraperitoneal fat body and liver in red sea bream. Furthermore, a decrease in the serum thiobarbituric acid value in black sea bream and a reduction of the adipocyte diameter in the APM-fortified groups of both fishes were observed. However, fortification of TA did not affect these parameters as significantly as did fortification of APM. The shortest recovery time to air-dipping was found in the APM+TA-fortified group, followed by the APM-fortified group in red sea bream. The results implied an effect of vitamin C on lipid metabolism, and acceleration of vitamin E absorption and/or suppression of vitamin E degradation.

View full abstract

The effects of photoperiod (PPD) and feeding interval on food intake and growth of Nile tilapia Oreochromis niloticus were investigated. In the first two trials, fish were subjected to PPD of 3L:3D (3LD), 6L:6D (6LD), 12L:12D (12LD) and 24L:24D (24LD) for 6 weeks at 28°C. In Trial 1, the fish (mean weight 3.45 g) were fed 5% of body weight per day and in Trial 2 fish (mean weight 3.60 g) were fed to visual satiation (four meals per day) according to the feeding interval specified for different treatments. In a third trial, fish subjected to 12LD were fed 6% of body weight per day and fish were given 12% every other day under 24LD. Fish exposed to a 6LD PPD had a significantly higher growth rate than those exposed to other PPD in Trials 1 and 2 (P<0.05). When the fish were fed to satiation, significantly higher food consumption and feed efficiency (P<0.05), and lower adiposity (P<0.05) were observed in fish exposed to 6LD PPD than those exposed to 12LD PPD. These results indicated that a 6LD PPD regimen resulted in an improvement of fish growth through stimulated food intake. Thus, these experiments suggested that the growth of Nile tilapia could be controlled by the manipulation of PPD and feeding interval.

View full abstract

Salted muscle paste containing 60-100 mg protein/g paste and 0.5 M NaCl at pH 7.0 was prepared from fresh scallop striated adductor muscle and its heat-induced gelling characteristics were examined in order to produce invertebrate kamaboko-like foods. The heating of the paste to 90°C formed a weak gel. The setting effect on the gelation of the paste was introduced by incubation at 25°C for up to 4 h and was greatly strengthened by the addition of 10 mM Ca²⁺ due to the activation of an endogenous transglutaminase that preferentially cross-linked myosin heavy chains, but not actin and paramyosin. As a result, the texture of the gel produced by a two-step heating method was almost the same as that of a commercial fish kamaboko. It was also observed that the thermal gelation profile of scallop muscle paste was similar to that of fish myosin, rather than that of actomyosin, by means of a dynamic rheological measurement. Paramyosin also contributed to a characteristic increase in the G' (storage modulus) value over the thermal gelation process and raised the G'' (loss modulus) value around 65°C. The G'' increase resulted in a slightly rigid texture of heated scallop gel. Isolated paramyosin demonstrated a characteristic thermal gelation profile showing a two-step increase in G' and G'' values, independent of Ca²⁺ concentration. The higher NaCl and protein concentrations were required to produce stronger and more elastic gels.

View full abstract

Transparent and flexible edible/biodegradable films were successfully made from myofibrillar proteins of blue marlin meat. The effect of pH of film-forming solutions on film formation, tensile strength (TS), elongation at break (EAB), water vapor permeability (WVP), light transmission, transparency, film solubility, protein solubility and enzymatic hydrolysis was investigated. Myofibrillar protein-based films were formed within pH 2-3 and 7-12, whereas films were not formed between pH 4 and 6 because of the poor protein dispersion around the isoelectric point. TS of the films was higher when prepared at the acidic (pH 2, 3) and alkaline (pH 11, 12) conditions, whereas EAB was almost constant irrespective of pH. On the whole, the pH of film-forming solutions had no effect on WVP, light transmission, film solubility and enzymatic hydrolysis. WVP of myofibrillar protein films were slightly lower than those of other protein-based edible films and higher by one to three orders of magnitude than those of synthetic films. The films prepared at lower or higher pH, which had a more stable protein network, possessed superior transparency close to synthetic films.

View full abstract

cDNA encoding tropomyosin was cloned from walleye pollack Theragra chalcogramma fast skeletal muscle. The predicted mass was 32 588 Da and isoelectric point, 4.55, assuming acetylation of the N-terminus. The full-length cDNA contained 1168 bp, comprising a 5'-untranslational region (97 bp), a 3'-untranslational region (219 bp) and an open reading frame of 855 bp encoding 284 amino acid residues. The deduced amino acid sequence showed considerably high homology in a range of 94-97% to those of other vertebrate α-type tropomyosins. In phylogenetic analysis, walleye pollack tropomyosin showed the closest relationship with the Atlantic salmon counterpart. By differential scanning calorimetry, pollack tropomyosin gave only one major endothermic peak at around 44°C. Circular dichroism spectra supported this denaturation profile of pollack tropomyosin.

View full abstract

Dielectric properties of surimi paste at 2450 MHz and 915 MHz were measured from 20°C to 80°C by the open-ended coaxial probe method. The dielectric constant and loss factor varied with temperature and salt content. With increasing salt content, the loss factor increased, while the dielectric constant decreased. The penetration depths of salted surimi were larger than those of unsalted surimi. Therefore, during microwave heating, the addition of salt may cause the surface heating phenomenon. Potato starch and corn starch were added to salted surimi; the type and content of starch added had no effect on the dielectric properties of salted surimi.

View full abstract

Physicochemical changes in black rockfish muscle subjected to saturated salt solution were investigated. The immersion of black rockfish in saturated salt solution accelerated rigor mortis of the muscle and full rigor was rapidly shortened by the increase of immersion time. However, the rigor index of samples immersed in a saturated salt solution decreased compared with that of samples killed instantly. The total content of ATP and related compounds in all samples was 7.2 μmol/g. However, ATP decreased in the samples immersed in a saturated salt solution. In addition, ATP content became lower as the immersion time was longer. Also, lactate accumulated, as immersion time was prolonged, in contrast with the decrease in the ATP. The breaking strength of samples immersed in the saturated salt solution was higher than that of samples killed instantly. The myofibrillar ATPase activities of the samples immersed in the saturated salt solution were higher than those of samples killed instantly.

View full abstract

Post-mortem muscle tenderization during chilled storage is thought to result from loss of physical strength due to the disintegration of intramuscular connective tissue. Although metalloproteinases may be involved in the disintegration, details of the proteolytic processes occurring during chilled storage remain to be elucidated. To determine the involvement of matrix metalloproteinase-9 (MMP-9) in the post-mortem disintegration of intramuscular connective tissue, we produced recombinant Japanese flounder MMP-9 (jfMMP-9) in COS-7 cells. The recombinant jfMMP-9 showed gelatinolytic activity in the zymographic analysis at chilled temperature, but no apparent proteolytic activity against the triple helical domain of types I and type V collagens. In contrast, recombinant jfMMP-9 solubilized type I collagen from a crude connective tissue preparation at chilled temperature. This finding, together with the fact that a protein corresponding to MMP-9 was immunologically detected in the muscle extract, indicates that MMP-9 may be involved in the disintegration of the intramuscular connective tissue that induces the post-mortem tenderization of fish muscle during chilled storage.

View full abstract

Changes of superoxide dismutase (SOD) activities and malonaldehyde (MA) contents in yellowtail Seriola quinqueradiata meat stored at 0°C were analyzed for 8 days. During storage periods, changes of MA contents and SOD activities were not so large. In the meats stored at 0°C, SOD activities and MA contents in the meats containing 0, 0.3, 0.6 and 0.9 M NaCl stored at 0 and -20°C were analyzed for 7 days and 12 weeks, respectively. In the meats stored at 0°C, SOD activities in the meats containing 0.9 M NaCl were lower than those of the control; however, MA contents in the former meats were significantly higher than those of the latter during storage. In the meats stored at -20°C, SOD activities in the meats containing NaCl were lower than those of the control, but again, MA contents in the former meats were higher than those of the latter during storage. A weak reverse correlation was observed between SOD acitivities and MA contents in the meats.

View full abstract

We cloned the cDNA and genes of two different types of CC chemokine from Japanese flounder Paralichthys olivaceus. The genes were designated JFCC1 and JFCC2. The JFCC1 cDNA encoded 91 amino acid residues. The JFCC1 gene has a size of 1.9 kb and consists of three exons and two introns. Two types of JFCC2 mRNA, corresponding to genes designated JFCC2-1 and JFCC2-2, were detected by reverse transcription-polymerase chain reaction in several organs, although fully spliced mRNA was not detected. The sizes of JFCC2-1 and -2 were 1.9 kb and 1.8 kb, respectively. JFCC2-1 consists of three exons and two introns and JFCC2-2 consists of two exons and one intron, although the coding regions of the two genes are identical. Because the JFCC2 gene has uncommon properties and an uncommon expression pattern, we suggest that it is a pseudogene. Southern blot hybridization and the characterization of BAC clones indicated that both the JFCC1 and JFCC2 genes exist as multicopy genes in the Japanese flounder genome. JFCC1 and JFCC2 genes were expressed in several organs including peripheral blood leukocytes (PBL) and kidney. The two forms of JFCC2 mRNA were also encountered in these cells. Expressions of JFCC1 and JFCC2 genes were upregulated after stimulation with concanavalin A/phorbol myristate acetate and lipopolysaccharide, compared with normal PBL.

View full abstract