Flounder Muscle Research Articles

Solubilization of type I and V collagens in Japanese flounder muscle during chilled storage

The post-mortem changes of type I and V collagens in Japanese flounder muscle during chilled storage were examined. The muscle softened significantly within 12 h under chilled storage. Both type I and V collagens isolated by ion-exchange chromatographies showed no remarkable changes in band patterns even after 24 h of storage, suggesting that degraded collagen molecules may be removed from the collagen fraction by a conventional preparation method. In contrast, type I and V collagen molecules were detected by Western blotting with each specific antibody in a saline extract and gradually increased during chilled storage. These results suggest that both type I and V collagens may participate in the post-mortem softening of fish muscle.

Identification and characterization of molecular species of collagen in ordinary muscle and skin of the Japanese flounder Paralichthys olivaceus

Pepsin-solubilized collagens prepared from ordinary muscle and skin tissues of the Japanese flounder (Paralichthys olivaceus) were separated into two fractions, major and minor, by ammonium sulfate precipitation. Collagens in these fractions were further purified by cation-exchange column chromatography. The results of SDS–PAGE, peptide mapping and amino acid analysis of collagen in both fractions suggested that the purified major and minor collagens might be classified as types I and V collagens, respectively. Each type of collagen was fundamentally similar, among the ordinary muscle and the skin, in amino acid composition and peptide maps.

Effects of hydrolysed fish muscle on intermediate process variables during twin-screw extrusion of rice flour

The effects of fish protein hydrolysis time and fish solids level on energy input, residence time, and die temperature during twin-screw extrusion of rice flour and fish muscle blends were investigated. Arrowtooth flounder muscle was autolysed for upto 15 min using muscle-bound protease, hydrolysed muscle was recovered, dried, blended with rice flour at 0, 5, 10, and 15 g/100 g levels, and extruded using a twin-screw extruder. Hydrolysis of arrowtooth muscle beyond 5 min had very little effect on energy input, residence time, mixing index and die temperature. Fish solids level played a dominant role in lowering specific mechanical energy input, raising the mean residence time, and reducing mixing. The effect on die temperature was different for unhydrolysed and hydrolysed fish muscle. The material temperature in the die was strikingly higher and increased with increasing level of hydrolysed fish solids in the blends. Opposite trend was observed for blends with unhydrolysed fish solids.

Cadmium accumulation and elimination in tissues of juvenile olive flounder, Paralichthys olivaceus after sub-chronic cadmium exposure

Experiments were carried out to investigate the accumulation and elimination of cadmium (Cd) in tissues (gill, intestine, kidney, liver and muscle) of juvenile olive flounder, Paralichthys olivaceus, exposed to sub-chronic concentrations (0, 10, 50, 100 μg l −1) of Cd. Cd exposure resulted in an increased Cd accumulation in tissues of flounder with exposure periods and concentration, and Cd accumulation in gill and liver increased linearly with the exposure time. At 20 days of Cd exposure, the order of Cd accumulation in organs was gill > intestine > liver > kidney > muscle and after 30 days of exposure, those were intestine > gill > liver > kidney > muscle. An inverse relationship was observed between the accumulation factor (AF) and the exposure level, but AF showed an increase with exposure time. During the depuration periods, Cd concentration in the gill, intestine and liver decreased immediately following the end of the exposure periods. No significant difference was found Cd in concentration in the kidney and muscle during depuration periods. The order of Cd elimination rate in organs were decreased intestine > liver > gill during depuration periods.

Lipid composition of yellowtail flounder ( Limanda ferruginea ) in relation to dietary lipid intake

Condition indices (CI), hepatosomatic indices (HSI) and proximate, lipid and fatty acid composition of wild and laboratory-reared yellowtail flounder (Limanda ferruginea) (Storer, 1839) were compared from data taken throughout spring and summer 1996–1998. Cluster analysis was performed on the fatty acid signatures of these two groups along with a commercial diet and several invertebrate species to determine possible feeding patterns in Conception Bay, Newfoundland. HSI and levels of storage fat were significantly higher in the muscle and liver of laboratory-reared yellowtail flounder, indicating an efficient absorption of dietary lipid and an increase in fat deposition. Fatty acid analysis of the liver showed that wild fish contained significantly higher proportions of the essential fatty acids 20:4ω6, 20:5ω3 and 22:6ω3; whereas proportions of 18:1 and 18:2ω6 were significantly higher in all fractions of lipid examined from laboratory-reared fish than they were from wild fish. Polar fractions of lipid were more similar than the neutral fraction of lipid when comparing wild and laboratory-reared fish. Taken together, the differences in CI, HSI, proximate and fatty acid composition suggest that feeding commercial diets to L. ferruginea can cause changes in patterns of lipid deposition and metabolism. Cluster analysis of marine plankton, sedimenting particulate matter, wild invertebrates, the commercial diet and fish tissues showed that the fatty acid signatures of both wild and laboratory-reared yellowtail flounder closely resembled their respective food items. Fatty acid signatures from wild fish were more closely related to plankton and settling particulate matter, suggesting relatively few steps in the food web leading to yellowtail flounder. In addition to the resemblance between fatty acids in the commercial diet and the tissues of laboratory-reared yellowtail flounder, these fish had similar fatty acid signatures to those of wild invertebrates.

Hydrolyzed Fish Muscle as a Modifier of Rice Flour Extrudate Characteristics

ABSTRACTThe effects of fish protein hydrolysis time and fish solids level on macroscopic properties of extrudates were investigated. Arrowtooth flounder muscle was autolyzed for varying times; hydrolyzed muscle was recovered, dried, blended with rice flour at varying levels, and extruded using a twin‐screw extruder. Hydrolysis beyond 5 min had little effect on extrudate properties. Addition of hydrolyzed fish solids strikingly decreased the apparent density and breaking strength but increased extrudate porosity and expansion ratios. In general, the effect was greater when the level of fish solids was higher. Opposite and expected trends were observed for blends with unhydrolyzed fish solids. Fish solids level played a dominant role in increasing true density.

Aqueous extracts from some muscles inhibit hemoglobin-mediated oxidation of cod muscle membrane lipids.

It was evaluated whether trout hemoglobin (Hb)-mediated oxidation of minced washed cod muscle lipids could be prevented by an aqueous isolate from cod and some other muscle sources. Lipid hydroperoxides and painty odor developed approximately 4 days faster in washed than unwashed cod mince. When adding back an aqueous fraction (press juice) isolated from unwashed mince to washed mince at 2-6-fold dilutions, development of hydroperoxides and painty odor was either delayed or completely prevented. The inhibitory substances were heat stable, and their effect was slightly reduced at reduced pH. The <1 kDa fractions of whole and heated press juices were as inhibitory as the unfractionated press juices. Inhibition by the unheated, heated, and ultrafiltered (30 kDa) press juices was lost after dialysis. These findings implied the presence of one or more highly effective aqueous low molecular weight antioxidants in cod muscle press juice. The same antioxidative properties were found in heated haddock, dab, and winter flounder muscle press juices but not in heated herring and chicken muscle press juices. Unheated chicken press juice was however highly inhibitory.

카드뮴 장기노출 후 넙치, Paralichthys olivaceus의 기관에 따른 카드뮴의 배출

넙치 (P. olivaceus)를 카드뮴 아치사 농도인 5, 50, 100 <TEX>${\mu}g/L$</TEX>의 구간에 30일간 노출시킨후 청장기간을 가져 아가미, 간, 신장, 창자 및 근육에서 축적된 카드뮴의 제거정도를 조사하였다. 아가미에서는 노출농도 50 <TEX>${\mu}g/L$</TEX> 이상에서는 배출 10일째부터 유의한 감소를 나타내었으며, 배출이 가장 빨랐던 기관은 창자로써 배출 10일째부터 노출농도 50, 100 <TEX>${\mu}g/L$</TEX>에서 <TEX>$50\%$</TEX> 이상의 제거율을 나타냈다. 간은 배출 10일째부터 유의한 감소를 나타냈으며, 노출 20일 이후에는 노출구간 50, 100 <TEX>${\mu}g/L$</TEX>에서는 각각 <TEX>$66.20\%$</TEX>와 <TEX>$86.22\%$</TEX>의 제거율을 나타냈다. 신장에는 카드뮴 노출이후 각 구간에서 유의한 감소를 나타내지 않았으며, 근육은 다른 기관들과는 달리 카드뮴 노출 이후 배출실험에서도 지속적인 농도 증가가 나타냈다. 카드뮴 노출 30일 후 배출되는 20일 동안 가장 많이 배출되는 기관의 순서는 창자>간<TEX>${\geq}$</TEX>아가미>>신장의 순으로 나타났다. 아가미, 창자와 간은 배출 20일 동안 급격한 카드뮴의 제거가 나타났으며, 신장은 유의적인 배출이 이루어지지 않고 농도변화가 거의 없었다. 근육은 배출이 이루어지지 않고, 카드뮴이 없는 해수에서도 지속적으로 증가하는 경향을 나타내었다. Experiments were carried out to investigate the elimination of cadmium in tissues (gill, intestine, liver, kidney and muscle) of flounder, Paralichthys olivaceus, after sub-lethal Cd exposure (5, 50, 100 <TEX>${\mu}g/L$</TEX>). During the depuration phase, Cd concentration in the gill decreased immediately following the end of the exposure period. The elimination rates at the end of depuration periods were <TEX>$18\%$</TEX> for 50 <TEX>${\mu}g/L$</TEX> exposure and <TEX>$70\%$</TEX> for 100 <TEX>${\mu}g/L$</TEX> exposure. Intestine showed fastest elimination rates of Cd at all concentration. At the end of the depuration period, the Cd concentration was similar to that in the control, Cd elimination in liver significantly decreased after 10 days of depuration period. After 20 days of depuration, the elimination rate was <TEX>$66.20\%$</TEX> in the fish exposed to 50 <TEX>${\mu}g/L$</TEX> and <TEX>$86.22\%$</TEX> in the fish exposed to 100<TEX>${\mu}g/L$</TEX>. The order of cadmium elimination in tissues were decreased intestine>liver<TEX>${\geq}$</TEX>gill>>kidney during depuration periods. In this study the gill, intestine and liver showed faster elimination rate of Cd in 50, 100 <TEX>${\mu}g/L$</TEX>-Cd exposure concentration. After the end of the Cd exposure, the Cd concentration in the kidney slowly decreased or remained constant and the Cd concentration in the muscle slowly increased or remained constant.

Purification and characterization of cathepsin L in arrowtooth flounder ( Atheresthes stomias) muscle

A predominant, heat-activated proteinase in muscle extract of arrowtooth flounder ( Atheresthes stomias) was purified to 55-fold by heat treatment, followed by a series of chromatographic separations. The apparent molecular mass of the purified enzyme was 27 kDa by size exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proteinase had high affinity and activity toward Z-Phe-Arg-NMec with K m and k cat values of 8.2 μM and 12.2/s, respectively. Activity was inhibited by sulfhydryl reagents and activated by reducing agents. The purified proteinase displayed optimal activity at pH 5.0–5.5 and 60 °C, respectively. Consistent with the properties of proteases from other species, the heat-activated proteinase in arrowtooth flounder can be identified as cathepsin L.

The analysis of immune responses of a novel CC-chemokine gene from Japanese flounder Paralichthys olivaceus

A novel CC-chemokine gene was isolated from the Japanese flounder Paralichthys olivaceus by expressed sequence tag analysis. The function of this CC-chemokine gene was studied by DNA injection. To investigate the immune responses to the CC-chemokine, a plasmid construct containing the novel CC-chemokine and a CMV promoter was injected into the epaxial muscle of Japanese flounder. Quantification of CC-chemokine protein expressed in serum on 1, 3 and 5 days after plasmid injection were estimated by ELISA. CC-chemokine gene injection increased the migration of phagocytic cells. Macrophage functions such as production of superoxide anion and phagocytosis were also stimulated by this gene injection. Thus, this gene from Japanese flounder has functional similarities to that of a mammalian CC-chemokine gene.

Bioaccumulation and Detoxication of Nodularin in Tissues of Flounder ( Platichthys flesus), Mussels ( Mytilus edulis, Dreissena polymorpha), and Clams ( Macoma balthica) from the Northern Baltic Sea

Cyanobacterial hepatotoxin accumulation in mussels ( Mytilus edulis, Dreissena polymorpha), clam ( Macoma balthica), and flounder ( Platichthys flesus) tissues was measured. Flounder were caught with gillnets from the western Gulf of Finland on 21 August 1999, 25 July 2000, and 25 August 2000. Blue mussels were collected from: (1) a steel cage at a depth of 3 m on 20 August 1999, (2) an enclosure at depths of 3–5 m, and (3) an artificial reef (wreck at 25–30 m) in the western Gulf of Finland between June and September 2000. Furthermore, blue mussels were collected from two sites between August and October 2000: south of the town of Hanko at depths of 5 and 20 m in the western Gulf of Finland and south of the city of Helsinki at a depth of 7 m in the central Gulf of Finland. M. balthica and D. polymorpha were collected at a depth of 12 m from Russian waters in the eastern Gulf of Finland on 1–4 August 2000. The samples were analyzed for the cyanobacterial hepatotoxins nodularin (NODLN) and microcystins (MCs) using enzyme-linked immunosorbent assay (ELISA), liquid chromatography–mass spectrometry (LC-MS), and matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF-MS). ELISA indicated a time-dependent accumulation of hepatotoxins in flounder liver up to 400±10 (SD) μg/kg on 25 August 2000. No hepatotoxins were detected in flounder muscle samples. In blue mussels, collected from an enclosure 3–5 m deep in the western Gulf of Finland on 23 August 2000, ELISA indicated cyanobacterial hepatotoxins up to 1490±60 μg/kg dry wt. Blue mussels collected from the other sites contained less cyanobacterial hepatotoxins (40–130 μg/kg dry wt). Clams and mussels from Russian waters contained cyanobacterial hepatotoxin at about 100–130 μg/kg dry wt. Total hepatotoxin levels in mussels from enclosures decreased from August to September, indicating at least partial detoxication/depuration of the toxins. LC-MS verified the presence of NODLN in mussels and flounder. Typical detoxication conjugates were observed by MALDI-TOF-MS in mussel samples collected during August 2000. In deeper-living wreck mussels cyanobacterial hepatotoxin levels continued to increase, from August to September, indicating that portions of cyanobacterial hepatotoxins reach the sea floor. NODLN bioaccumulation is a constant phenomenon in the area.

Accumulation of tributyltin in the blood of fish: Its application for monitoring in the marine environment

Accumulation of tributyltin (TBT) in serum, liver, muscle, and gill of olive flounder (Paralichthys olivaceus) was examined in a 30-d static-renewal exposure. Tributyltin accumulated rapidly in the serum of the olive flounder and to a greater extent than in the other tissues. The accumulated TBT concentrations in tissues were in the order of serum > gill > liver > muscle on a dry-weight basis. Tributyltin also was detected in the serum of feral fine-spotted flounder, Pleuronichthys cornutus, collected from the coastal area. The mean TBT concentration in serum (2,470 ng Sn/g) of the fine-spotted flounder was about 40 times higher than that in the liver (60 ng Sn/g) and 200 times higher than that in the muscle (27 ng Sn/g) on a dry-weight basis. The TBT concentrations in serum and sediment demonstrated a positive correlation. The percent TBT composition to total butyltin was much higher in the serum (71%) than in the other tissues and sediment (<47%). These results suggest that the analysis of fish blood serum could be a useful tool for monitoring exposure to TBT in the marine environment.

Effects of Dietary Protein Sources on Growth and Body Composition in Olive Flounder (Paralichthys olivaceus)

A 6-week feeding trial was conducted to investigate the effects of six different dietary animal protein sources on growth and body composition of olive flounder, Paralichthys olivaceus in recirculating system. White fish meal (WFM), flounder muscle (FLM), carp muscle (CM), blood meal (BM), squid liver powder (SLP) and casein (CA) were used as the main animal protein sources in the six experimental diets. Fish averaging <TEX>$2.9\pm0.03g$</TEX> <TEX>$(mean\pm SD)$</TEX> were distributed to each aquarium as a group of 15 fish and were fed one of the six experimental diets to each treatment of triplicate groups. After 6-week of the feeding trial, fish fed white fish meal (WFM) and flounder muscle (FLM) diets showed a significant higher weight gain <TEX>$(WG\%)$</TEX> (P<0.05) than those of fish fed the CM, BM, SLP and CA diets. Fish fed BM diet showed the lowest WG among all the dietary treatments. Feed conversion ratio (FCR) and protein efficiency ratio (PER) showed the similar trend as WG. Hematocrit and hemoglobin were not affected by the dietary treatments. Fish fed the FLM and CM diets showed significant higher survival rate than those of fish fed BM diets, and there was no significant difference in survival of fish fed WFM, FLM, CM, SLP and CA diets. These results indicated that WFM and FLM are the best dietary protein sources tested in olive flounder.

The Development of a Rapid and Sensitive, High-Through-Put Protocol for RNA:DNA Ratio Analysis

Abstract We present a new technique for determining RNA:DNA ratios in larval and juvenile fish that relies on the rapid homogenization of samples with salts, detergents, and proteinase K and the detection of DNA and RNA with specific fluorescent dyes. Samples are not purified before assay of nucleic acids. The technique was designed for use in 96 or 384 well plates and required only 50 μL of sample per well. The detection of RNA and DNA is linear over 500 ng and is sensitive to a nucleic acid content as little as that within 50 μg of tissue. The new technique was used to characterize the RNA:DNA ratio in the white muscle of juvenile mummichogs Fundulus heteroclitus and larval winter flounder Pleuronectes americanus. This technique was compared with other techniques that use fluorescent dyes to determine the RNA:DNA ratio in fish samples.

Cloning and sequence analysis of the interleukin-8 gene from flounder ( Paralichthys olivaceous)

A cDNA library of mRNA from flounder leukocytes stimulated with bacterial lipopolysaccharide (LPS) and hemagglutinin was constructed to clone cytokine genes of this fish. Initial screening of this library with human cytokine gene probes was not productive and clones with inserts of over 400 nucleotides (nt) were randomly sequenced, and a homologue of the vertebrate interleukin-8 (IL-8) gene was isolated. The flounder IL-8 cDNA encompassed 884 nt, including a coding region of 330 nt. Four cysteines characteristic of CXC chemokines were identified at conserved locations in the putative protein. The deduced amino acid sequence showed 36 and 35% sequence identity with counterpart genes in monkey and human, respectively, and 52% sequence similarity with these genes. However, the putative flounder IL-8 amino acid sequence showed 25% identity and 52% similarity to that of lamprey, the only other piscine IL-8 gene that has been cloned. Flounder IL-8 transcripts were detected in the head-kidney and spleen of LPS-injected flounder and leukocytes stimulated with LPS. It was not detected in the muscle or liver of LPS-injected flounder, tissues taken from non-stimulated flounder and non-stimulated leukocytes.

Cathepsin L: a predominant heat-activated proteinase in arrowtooth flounder muscle.

Characterization of the autolytic profile of arrowtooth flounder (ATF) muscle indicated the involvement of heat-activated proteinases active at both acidic and alkaline pH values. Further assay of fish extract exhibited the maximum activity at 60 degrees C against casein used as a substrate at both pH 5.5 and 8.0. The maximum activity shifted to lower temperatures by the addition of urea with two distinctive patterns: activity reduction at pH 5.5 and activity enhancement at pH 8.0. The highest inhibition by E-64 indicated the proteinase belongs to the cysteine proteinase class. At pH 5.5, the proteinase hydrolyzed Z-Phe-Arg-NMec and all types of protein substrates tested at higher rate than that at pH 8.0. Activity bands, observed on the activity-stained substrate gels, indicated similar proteinases are responsible for the proteolytic activity observed at both pH values. When proteins of fish extract were separated by HPLC-SEC, only one proteolytic peak was observed at the retention time of 26 min with an estimated molecular weight of 39800 Da. The results implied cathepsin L is a predominant proteinase responsible for autolysis of ATF muscle at elevated temperatures.

A Preliminary Study on the Dietary Protein Requirement of Larval Japanese FlounderParalichthys olivaceus

Abstract This experiment was conducted to estimate the dietary protein requirement of larval Japanese flounder Paralichthys olivaceus (also known as the olive flounder) and to examine the effects of a commercial diet and three experimentally developed microparticulate diets (MPDs) on their growth and body composition. Larvae were fed four MPDs for 75 d beginning 8 d after hatching (DAH); fish in these experimental diets were also concurrently fed live feeds until 45 DAH, as is the normal procedure in commercial hatcheries. One MPD was a commercial diet (CD) of marine fish in which crude protein ranged from 55.8% to 61.2% (dry weight basis; varied with pellet size); the three laboratory-prepared diets based on Japanese flounder muscle contained either 40% (D40), 50% (D50), or 60% (D60) crude protein. At 83 DAH, body weights and lengths of fish fed diet D60 were not significantly different from those fed diet CD. Fish fed diet CD had significantly greater body weights and lengths than those fed diets D40 an...

The first observation of okadaic acid in flounder in the Baltic Sea

Abstract Okadaic acid (OA) is a relatively stable polyether toxin causing diarrhetic shellfish poisoning, DSP. OA is produced by dinoflagellates such as Dinophysis acuminata and D. norvegica, which are common throughout the Baltic Sea. This protein phosphatase (PP) inhibitor can induce toxic effects such as hepatocyte apoptosis after in vitro exposure. The aim of this study was to analyse the liver and muscle of flounder from the Baltic Sea for okadaic acid. 30–50 flounder (Platichthys flesus) were caught at depths between 6 and 20 meter in different areas of the northern Baltic Sea every 3–4 weeks in June– September 1996–1998. The presence of OA was analysed using HPLC. The flounder caught in August 1996 contained OA (222 ng OA g-1 ww, liver tissue). This was the first observation of OA in fish from the northern Baltic Sea.

Determination of roxithromycin residues in the flounder muscle with electrospray liquid chromatography–mass spectrometry

A highly sensitive and specific method for the determination of roxithromycin in the flounder muscle by LC–MS was developed and validated. A dichloromethane extract of the sample was separated on C 18 reversed-phase column with acetonitrile–50 m M ammonium acetate (80:20, v/v) as the mobile phase and analyzed by LC–MS via atmospheric pressure ionization/electrospray ionization interface. The limit of detection and limit of quantitation were 0.01 and 0.1 ng/g, respectively. Mean recoveries from spiked muscles were 81.1% (ranged from 71.0 to 90.3%) for roxithromycin. The method has been successfully applied to determine roxithromycin in the flounder muscle.

The Use of Cholinesterase Activity in Flounder ( Platichthys flesus) Muscle Tissue as a Biomarker of Neurotoxic Contamination in UK Estuaries

This study investigated the occurrence and levels of neurotoxic contamination in UK estuaries by the determination of cholinesterase (ChE) activity in the muscle of the flounder ( Platichthys flesus). Samples were obtained from 16 sites in the estuaries of the rivers Humber, Mersey, Tamar, Tees and Tyne. ChE activity levels were compared to those at a reference site- the River Alde, Suffolk. Twelve sites exhibited significantly ( p<0.05) reduced ChE activity. The Tyne estuary showed a strong gradient of effect that suggested a source of neurotoxic-contamination upstream of the sampled sites. Representative water samples from several of the estuaries were analysed for the presence of 32 organophosphate (OP) and 20 carbamate (C) pesticides from which residues of nine OPs and six Cs were detected. Correlation analysis of ChE activity with gender, size, GSI, HSI and condition factor suggested that these variables did not influence neural activity in this study. It was concluded that the reduction in ChE activity was contaminant mediated and that OP and C pesticides were probable contributors. Influences on ChE activity, higher order implications and its use as a monitoring tool, including reactivation techniques, are discussed.