Bastard Halibut Paralichthys Olivaceus Research Articles

Functional characterization of obscure puffer ToNK-lysin: A novel immunomodulator possessing anti-bacterial and anti-inflammatory properties

NK-lysins are one of the most abundant antimicrobial peptides produced by cytotoxic T lymphocytes (CTLs) and natural killer cells (NKs), and identified as a new class of intrinsically disordered proteins, playing critical roles in the cell-mediated cytotoxicity response, as well as immunomodulatory and antimicrobial activities upon a significant range of pathogens. In the present study, an NK-lysin was identified from Obscure puffer Takifugu obscurus (ToNK-lysin). The open reading frame of ToNK-lysin sequence spans 423 bp, encoding a peptide with 140 amino acids which shares a moderate residue identity (18%–60%) with NK-lysin of mammals and other teleost species. Phylogenetic analysis revealed that ToNK-lysin was most closely related to NK-lysins from the Pleuronectiformes (Bastard halibut Paralichthys olivaceus and Pacific halibut Hippoglossus stenolepis). Comprehensive computational analysis revealed that ToNK-lysin have substantial level of intrinsic disorder, which might be contribute to its multifunction. The transcripts of the ToNK-lysin were detected in multiple examined tissues and most abundant in gills. After bacterial and Poly I:C challenge, the transcriptional levels of ToNK-lysin were significantly up-regulated in the head kidney, liver and spleen at different time points. The recombinant ToNK-lysin showed significant antibacterial activity against Vibrio harveyi and Escherichia coli, and the ToNK-lysin treatment not only reduced the bacterial loads in liver and head kidney, but also alleviated the pathogen-mediated upregulation of immune-related genes. In addition, the co-incubation with rToNK-lysin protein remarkably degraded bacterial genomic DNA, suggesting the potential mechanism of ToNK-lysin against microbes. These results suggest that ToNK-lysin possess antibacterial and immunoregulatory function both in vivo and in vitro, which may allow it a potential applicability to the aquaculture industry.

Isolation and characterization of an adenylate kinase from the lateral muscle of bastard halibut Paralichthys olivaceus

Adenylate kinase (ATP:AMP phosphotransferase, EC 2.7.4.3) (AK) is the enzyme that catalyzes the reversible conversion of MgATP + AMP to MgADP + ADP, a principal step in adenine nucleotide metabolism and cellular energy homeostasis. To enrich the information about fish AKs, we isolated this enzyme from the lateral muscle of bastard halibut Paralichthys olivaceus and biochemically characterized it. The halibut enzyme (PoAK) extracted from the lateral muscle was purified by column chromatographies on TOYOPEARL SP-650 M and Superdex 75 10/300. The purified PoAK showed a single protein band of ~ 22 kDa on SDS–polyacrylamide gel electrophoresis, and optimal temperature and pH at around 40 °C and 7, respectively. PoAK was appreciably heat stable, e.g., the temperature that caused 50% inactivation during 30-min incubation was 54 °C. The molar ratio for ATP:ADP:AMP in the equilibrium state of the reaction was ~ 1:1:1. Peptide mass fingerprinting indicated that PoAK is the product of adenylate kinase isoform 1 gene (GenBank, XP_019937160.1) encoded in the halibut genome. The deduced amino-acid sequence of the halibut AK comprised 194 residues and showed 92, 91 and 81% amino-acid identities to those of a putative rainbow trout AK, a carp AK and a chicken AK, respectively.

넙치(Paralichthys olivaceus) 알로부터 Serine Protease Inhibitors의 분획 특성

Protease inhibitors (PI) of trypsin and papain as target proteases from the roe of bastard halibut Paralichthys olivaceus were fractionated out using ammonium sulfate precipitation (A), DEAE 650M anion exchange chromatography (D), and Sephacryl S-300 gel filtration (S). The recovery percentages of the fractions with the strongest inhibitory activity for each fractionation method were 13% for the A4 fraction, 21.2% for the D3 fraction, and 21.3% for the S2 fraction, with specific inhibitory activities of the fractions toward trypsin and casein of 168, 139, and 218 U/mg, respectively, while no inhibition of papain was observed. The for the trypsin-specific substrate -benzoyl--arginine-p-nitroanilide (BAPNA) was 0.65, 1.55, 2.26, and 2.85 mg/mL for the A4, S2, A3, and D3 fractions, respectively. These results suggest that chromatographic fractionation methods (D and S) based on the molecular mass and charge of the protein were more effective at fractionating PI than was ammonium sulfate precipitation based on protein solubility, and that the bastard halibut roe extract acts as a serine protease inhibitor. Therefore, the PI fraction from fish roe might be useful for inhibiting proteases in foodstuffs, and could constitute an alternative food-grade inhibitor for the surimi industry.

RSM을 이용한 비규격 제주산 양식 넙치(Paralichthys olivaceus)로부터 연제품의 가공 조건 최적화

This study was conducted to optimize the processing of high quality surimi gel from unmarketable cultured bastard halibut Paralichthys olivaceus. According to endogenous enzyme activity and processing optimization, high quality surimi gel from unmarketable cultured bastard halibut was prepared by mixing 3.0% (w/w) salt, 2.4% (w/w) starch, 5.0% (w/w) egg white and 4.8% (w/w) ice water in a Stephan mixer, set at <TEX>$5^{\circ}C$</TEX> for 24 h, followed by boiling for 30 min, and finally cooling for 30 min. The strength of the surimi gel from unmarketable cultured bastard halibut prepared by the above processing method was <TEX>$1,257\;g{\times}cm$</TEX>, which was 33% higher than that of a commercial surimi gel from Alaska pollock, grade SA.

Mercury levels of small fishes: influence of size and catch area

In the present study, we assessed small fishes as potential feed fishes with the lowest mercury levels. The mercury levels of four small pelagic fishes and a benthic fish from the Pacific Ocean and the Sea of Japan, i.e., spotted chub mackerel Scomber australasicus, chub mackerel Scomber japonicus, horse mackerel Trachurus trachurus, round scad Decapterus punctatus, and bastard halibut Paralichthys olivaceus, were determined. Total mercury levels in fish muscle were measured using a reduction vaporizing atomic absorption method. There were no significant correlations between body weight and mercury levels for these species. However, significant differences were observed in the mercury levels of these species between the two catch locations, with fish caught in the Pacific Ocean having higher mercury levels. This difference may be due to the Pacific Ring of Fire, a highly seismically and volcanically active zone, which is located in the Pacific Ocean. Preference for these fishes for use in aquaculture should refer to the area where they are caught in addition to the species.

Multiple taste functions of the umami substances in muscle extracts of yellowtail and bastard halibut

Boiled muscle extracts obtained from yellowtail Seriola quinqueradiata and bastard halibut Paralichthys olivaceus were treated with two kinds of purified enzymes (acid phosphatase and glutamate decarboxylase), and the change in contents of nucleotides, related compounds, and free amino acids was examined. The change in taste qualities was also investigated by a taste test. The enzyme treatment resulted in a marked decrease in the contents of such umami substances as inosine 5′-monophosphate (IMP) and glutamic acid (Glu). The taste test revealed that the treatment of these fish muscle extracts with both or either of the enzymes caused a sharp decrease in umami intensity and also an increase in sourness but not a change in pH. The treatment also effected marked decreases in thickness and overall taste intensity. These findings suggest that IMP and Glu function not only to intensify the thickness and overall taste as well as the umami, but also to repress the sourness sensation elicited by the fish muscle extracts.

A record of a crustacean parasite Argulus matuii (Branchiura: Argulidae) in finfish mariculture in Japan

Four specimens of crustacean parasite were collected from the caudal fin and caudal peduncle of a bastard halibut Paralichthys olivaceus (Temminck and Schlegel) cultured in Saiki Bay, the western Bungo Channel (western North Pacific), off Shirahama, Oh-nyu Island, Saiki, Oita Prefecture, Japan in June 1992. The specimens were lost but one of them was identified as the argulid branchiuran Argulus matuii Sikama, 1938, based on its morphological characters recorded on a photograph of the whole body. This finding represents the first record of A. matuii from farmed marine fishes. P. olivaceus is a new host for A. matuii. A total of 8,165 specimens belonging to 57 species of marine fishes cultured in coastal waters of Oita Prefecture were examined for parasitic diseases for 18 years from 1980-1997, but only three cases of argulid infection, including the present case, were found, indicating that argulids are very rare parasites in finfish mariculture in this prefecture.

Carbon budget of bastard halibutParalichthys olivaceus in relation to body weight and temperature

The effects of body weight and temperature on the carbon budget of the juvenile bastard halibut,Paralichthys olivaceus, were studied at temperature 13.5, 18, 21.5 and 24 °C, respectively. The carbon intake, faecal and growth carbon were measured, and the carbon respiration was calculated using the carbon budget equation (Cc=Gc+Fc+Rc). The combined relationship between different components of the carbon budget, body weight and temperature could be described by regression equations:Cc=1.0206W0.8126e0.1483T;Gc=0.0042W1.4096(−5.11T3+285.90T2−5173.72T+30314.03);Fc=0.0485W0.77t1 e0.1624T;Uc=1.4333W0.6715 e0.1487T. Body weight had no significant effect on the carbon absorption efficiency and the conversion efficiency.

圧電センサを利用した魚類の聴覚しきい値測定

Using a classical respiratory conditioning technique, this experiment was carried out to examine the possibility of using a piezoelectric sensor (Kynar; 20mm long, 0.2mm thick) to observe a conditioned response. We used 2 fishes of different body style, the bastard halibut Paralichthys olivaceus and the tilapia Tilapia niloticus. The sensor was fitted on a gill cover to detect the respiratory activity, opening and shutting motion. The heart-beat was detected by ECG. After classical conditioning, the conditioning response was measured as suppression both in the respiratory activity and the heart-beat. The two factors coincided with each other. The method of measuring the respiratory activity by the piezoelectric sensor was found to be very useful for measuring the auditory threshold because of its ease of operation, apparent response and greater signal than that of the ECG.

ヒラメの網いけす内における遊泳能力について

Swimming speed-fatigue tests were conducted to understand the performance ability of bastard halibut Paralichthys olivaceus. In a small circular tank, a polyethylene net was set on a slant and the fish was put onto the net with its blind side facing a water current. Fish of 4.6 to 36.3cm in total length (L) were classified into 5 size groups and fatigue time was measured at 5 water temperature ranges. Fatigue time, defined as the length of time for a caudal fin to touch the metal grating at the downstream end of the working section of the tank, was measured by the changes in the current velocity (V). Swimming ability index (SAI=∫36000V•L-1dt×10-4) was calculated. For comparison, a fatigue test was also done on barfin flounder Verasper moseri. For bastard halibut, fatigue time was longer in higher temperatures with smaller fish having a higher performance in SAI at the same temperature. At 17°C, fatigue time was estimated over 3 hours in 1 L/s; and a few minutes in 2 L/s. Barfin flounder showed a higher performance than bastard halibut.

ヒラメの聴覚しきい値

Using a classical respiratory conditioning technique, the hearing ability of the bastard halibut Paralichthys olivaceus was measured for 7 fish at 7 frequency points between 70Hz and 500Hz. The conditioning response was measured as suppression in the respiratory activity by the piezoelectric sensor fitted on a gill cover in a quiet water tank. The bastard halibut was sensitive to sounds in the frequency range from 70Hz to 500Hz. The auditory thresholds were observed among the 7 fish with much difference (about 17dB) at 100Hz and 300Hz. But the audiogram had common characteristics that they had the lowest threshold at about 100Hz and that the threshold increased rapidly with frequency of sound between 200Hz and 400Hz.An attempt was also made examine the escape response of each of the above 7 bastard halibut by the sound stimulus, but no conditioned escape response was observed after 7 times applying training stimulus.

網生いけす内におけるヒラメとスナガレイの流れに対する定位能力

To estimate and control the water current velocity at the bottom of a net cage for aquaculture of benthic fishes, it is necessary to know the stationary-holding ability of the fish in the net. In this ex-periment, bastard halibut Paralichthys olivaceus and dead longsnout flounder Limanda punctatissima were used. A net was laid horizontally inside a small flume tank. Then the fish was carefully placed inside in such a way that its body axis was parallel to the stream line and its head was at the upper stream side. For bastard halibut, each fish was allowed to stay appoximately 5 minutes in the tank. A slow water current was applied and increased gradually. The current velocity at the time when the fish slipped and could not hold the same position inside, was recorded and termed as the slipping speed. The coefficient of static friction between the fish body and the net plane was calculated by the angle of the slope. The relationship between total length l and slipping speed us was expressed by the function us=k3√l in both two species. The value of proportional constant k3 was 3.2 (CM/s2)1/2 in bastard halibut, 3.3(cm/s2)1/2 longsnout flounder. For bastard halibut of 1.0kgf weight and 45cm total length, the average slipping speed was 21cm/s.

Studies for Coastal Fisheries Stock Management-III. A Simulation Model of Gear Efficiencies of Trawlers for Flatfish.

This paper proposes a simulation model of the gear efficiencies of trawlers for flatfish in order to predict the effectiveness on the limitations of horsepower of engines and gear scales. Gear efficiency of each boat is defined as (catching efficiency)×(swept area per tow)⁄(size of fishing areas). The catching efficiency is presented by a function of the gear scales, the depth of fishing area and the horsepower of engines, with the probabilities of a fish reacting at contact to ground gears and with distance of jump of fish. The swept area per haul is defined as (distance between two otter boards)×(towing speed)×(towing time), and is expressed by a function of the variables and the towing time. The parameters of the probabilities are estimated by the method of least squares from data of the above variables of boats, CPUE in the same month and fishing area and the distance of jump of fish. From the estimations from the data of five trawlers mean catching efficiencies for bastard halibut Paralichthys olivaceus are 0.031-0.125 haul-1 for (distance of jump)=1-5m. The problems in the model and estimation method, the results of the estimations, and the limitation for applications are discussed.

Studies of cysteine protease active in an acidic pH range of fish. I. Existence of cysteine proteinase active in an acidic pH range in fish.

The autolytic activity of various fish(16 species) muscle homogenate in an acidic pH range was measured in the presence of leupeptin and/or pepstatin A. The activity between pH 3 and 5 was inhibited by leupeptin as well as by pepstatin A in all fish examined. Especially, the activities of pointhead flounder Cleisthenes herzensteini, frog flounder Pleuronichthys cornutus, horse mackerel Trachurus japonicus and reticulated emperor Lethrinus semicinctus were inhibited chiefly by leupeptin The hemoglobin hydrolyzing activities of the crude extract from many fish muscles and livers in the presence of pepstatin A show the maximum activity at pH 4.0, and the activities of fish (53 species) muscles and livers in the presense of pepstatin A and/or leupeptin were measured at pH 4.0. The activities which was not inhibited by pepstatin A but inhibited by leupeptin were detected in almost all fish muscle and liver, and the activities of Pleuronectiformes (flathead flounder Hip-poglossoides dubius, frog flounder, pointhead flounder and bastard halibut Paralichthys olivaceus) were high. It was considered that the activity was due to the cysteine proteinase differing from cathepsin B or L.