Oyster Muscle Research Articles

Comparison and measurement of concentrations of heavy metals including cadmium and lead in oyster tissue of knife handle (Von Cosel, 1989) Solen dactylus in coastal waters of Hormozgan province (Tiab and Sirik)

This study aimed to measure the concentrations of lead and cadmium in the muscle tissue of Solen dactylus oyster in Tiab and Sirik areas located in Hormozgan province. To conduct this research, in the summer of 1397, 30 Solen dactylus oysters were collected from each of the mentioned areas and then bioassay operations were performed in the laboratory. Atomic absorption spectrophotometry was used to measure the concentration of lead and cadmium. Atomic absorption spectrophotometry was used to measure the concentration of lead and cadmium. The recorded results for the mean concentrations of lead and cadmium showed that there is a significant difference between Tiab and Siric stations (p≤0.05), And the highest mean concentrations of lead and cadmium were observed in oyster muscle tissue of knife handle, lead (0.761±0.065) and cadmium (0.506 ± 0.75) in the samples of Tiab station, respectively. The results show that factors such as the habitat of Solen dactylus affect the accumulation of heavy metals lead and cadmium, so that Tiab station shows higher pollution than Sirik station. On the other hand, the amount of these heavy metals in the oyster tissue of the knife handle at Tiab station is higher than the standard of the World Health Organization (WHO) and also in the Sirik region, the concentration of lead is lower and the concentration of cadmium is higher than the WHO. It turns out that the consumption of knife oysters both as shrimp food and by humans should be accompanied by health considerations.

Differential Gene expression related to morphological variation in the adductor muscle tissues of diploid and triploid fujian oysters, Crassostrea angulata

The Fujian oyster, Crassostrea angulata, accounts for approximately 50% of the total oyster production in China and is one of the most economically important marine products. In this study, we investigated differential gene expression profiles between diploid (n = 2) and triploid (n = 3) oysters that may indicate the specific adaptation associated with ploidy. A total of 14,626,126 and 15,492,551 reads were generated from diploid and triploid oyster muscle transcriptomes using Illumina RNA-Seq respectively. Gene expression analysis revealed a total of 2,045 differentially expressed genes between 2n and 3n individuals, from which 814 genes were significantly up-regulated in the 2n transcriptome while 1,231 were down-regulated. In addition, 24 differentially expressed genes (DEGs) were uniquely expressed in 2n individuals while 28 DEGs were uniquely expressed in 3n individuals. Furthermore, our pathway analysis suggested that the DEGs up-regulated in 2n oysters were enriched in the pathways related to normal growth, development and reproduction, whereas DEGs up-regulated in 3n individuals may be involved in faster growth and metabolism. Finally, we validated the expression levels of 15 genes using quantitative real-time PCR (qRT-PCR), and 14 out of 15 genes showed consistent expression patterns with RNA-Seq data. This study provides an important foundation for further investigations on distinct gene expression patterns and signalling pathways that differ between diploid and triploid oysters.

Extraction of bioactive compounds from oyster (Crassostrea gigas) by pressurized hot water extraction

Pacific oyster muscle hydrolysates were prepared by pressurized hot water extraction (PHWE) at process conditions ranging 125 °C/20 bar ∼ 275 °C/140 bar to investigate various physico-chemical and bio-functional parameters. Degree of hydrolysis was increased with increasing temperature and pressure and at 275 °C/140 bar, hydrolysis was found to be highest. Glycogen, protein, reducing sugar, and phenolic content of the hydrolysates were increased obtained from 125 °C/20 bar to 225 °C/100 bar, but decreased after raising over 250 °C/120 bar. Total and free amino acid contents were subsequently decreased as temperature and pressure increased over 175 °C/60 bar. Radical scavenging activity and antihypertensive activity was found to be highest at 225 °C/100 bar at which condition, the protein molecular size and carbohydrate molecular weight of the hydrolysates were 15 kDa or lower and 300–1000 Da, respectively. This study suggests the 225 °C/120 bar conditions for bio-functional Pacific oyster hydrolysate preparation.

Omega-3 fatty acids concentrate production by enzyme-catalyzed ethanolysis of supercritical CO2 extracted oyster oil

The separation of oil by a suitable technique from the Pacific oyster muscle is important for the utilization of the oil as a ω-3 polyunsaturated fatty acids (ω-3 PUFAs) source and production of bio-functional peptides/ oligosaccharides from oil-free residue. This study was conducted to prepare ω-3 PUFAs concentrate from supercritical carbon dioxide (SC-CO2) extracted Pacific oyster oil by enzyme-catalyzed ethanolysis reactions. SC-CO2 extractions were done at different temperatures and pressures to optimize suitable extraction conditions and extracted oils were compared with Soxhlet (n-hexane) extracted oil to evaluate the yield and quality. Oil extracted by SC-CO2 at optimized conditions was used for ethanolysis reaction catalyzed by immobilized sn-1,3 specific lipases, namely Novozymes-435, Lipozyme TLIM, and Lipozyme RMIM to produce 2-monoacylglycerols (2-MAG) rich in ω-3 PUFAs. The optimum temperature and pressure for SC-CO2 extractions of oyster oil was 50°C and 30 MPa. In this condition, the yield of oil was 5.96% and the acid, peroxide, free fatty acid, and p-anisidine values were 4.49 mg KOH/g, 4.72 meq/kg, 3.42%, and 10.03, respectively. The ω-3 PUFAs content significantly increased in 2-MAG obtained from Novozymes 435, Lipozyme TLIM, and Lipozyme RMIM to 43.03 ± 0.36, 45.95 ± 0.29, and 40.50 ± 0.77%, respectively (p < 0.05). A thin layer chromatography (TLC) analysis confirmed the production and separation of 2-MAG in the ethanolysis process. The ratio of total ω-3 to ω-6 fatty acids was almost twice in 2-MAG of SC-CO2 extracted oyster oil. SC-CO2 extracted Pacific oyster oil can be used for sn-1,3 specific lipases catalyzed ethanolysis to produce ω-3 PUFAs rich in 2-MAG.

진주조개(Pinctada fucata) 추출물의 가공 및 품질특성

This study examined the effective utilization of pearl processing by-products. Three extracts of hot-water extract (WE), hydro-cooked extract (HE), and two-step enzymatic hydrolysate (EH) were prepared from pearl oyster muscle, and their characteristics were examined. The moisture, crude protein, volatile basic nitrogen (VBN), and amino-N contents were 97.5-98.0%, 0.5-1.3%, 2.1-4.9 g/100 mL, and 35.0-74.5 g/100 mL, respectively. EH had the lowest VBN and highest amino-N contents. In addition, EH had the highest yields. In terms of its functional properties, EH inhibited angiotensin-I converting enzyme (<TEX>$IC_{50}$</TEX>, 1.39 mg/mL) more strongly than the other extracts (<TEX>$IC_{50}$</TEX>, 4.17-7.95 mg/mL). The free amino acid contents of WE, HE, and EH were 661, 470 and 1,150 mg/100 mL, respectively. Major amino acids were taurine and glutamic acid. Major inorganic ions were Na, Mg, and Ca. Contents of taste compounds, such as free amino acids, inorganic ions, and quaternary ammonium bases, differed significantly according to the extract methods. Based on the results of chemical experiments and sensory evaluation, the quality of EH was superior to the other extracts, and EH is suitable for use in natural flavoring materials.

진주 가공부산물(육 및 패주)의 이화학적 특성

This study was conducted to evaluate a knowledge on food components of muscle and adductor muscle of pearl oyster (Pinctada fucata martensii) as pearl processing byproducts. The concentrations of mercury and chromium as heavy metal were not detected in both pearl oyster muscle and adductor muscle, and those of cadmium and lead were 0.06 ppm and 0.11 ppm in only pearl oyster muscle, respectively. Thus, the heavy metal levels of pearl processing byproducts were below the reported safety limits. The volatile basic nitrogen (VBN) content and pH of pearl oyster muscle were 11.6 mg/100g and 6.31 and those of abductor muscle were 8.6 mg/100 g and 6.33, respectively. It was concluded that pearl oyster muscle and adductor muscle might not invoke health risk in using food resource. The contents of crude protein (16.5%) and total amino acid (15,691 mg/100 g) of adductor muscle were higher than those of muscle (11.2% and 10,131 mg/100 g) and oyster (12.1% and 11,213 mg/100 g) as a control. The contents of calcium and phosphorus were 95.4 mg/100 g and 116.0 mg/100 g in muscle, 75.2 mg/100g and 148.1 mg/100 g in adductor muscle, respectively. The calcium level based on phosphorus was a good ratio for absorbing calcium. The free amino acid contents and taste values were 635.5 mg/100 g and 40.2 in muscle, and 734.9 mg/100 g and 24.1 in adductor muscle, respectively, but that (882.8 mg/100 g and 40.2) of oyster was higher than those of pearl processing byproducts. Based on the results of physicochemical and nutritional properties, pearl oyster muscle and adductor muscle can be utilized as a food resource.

Quantitative analysis of microdebriders used in endoscopic sinus surgery

Purpose: To develop a standardized in vitro model for evaluating efficacy of the microdebriders and to assess whether differences in efficacy exist among available microdebriders. Microdebriders combine suction of tissue with amputation by a hollow rotating cutter. Several models are available, and they are increasingly popular in endoscopic sinus surgery. Materials and Methods: Seven microdebriders were tested by using a standardized soft tissue model (standard fresh raw oysters excluding muscle) and a firm tissue model (standard fresh raw oyster muscle). Efficacy was measured in grams of tissue aspirated per minute. Models to simulate lamina papyracea (eggshell) and dura (egg sac) were also tested with each microdebrider. Results: Statistically significant differences in soft tissue aspiration were found between most microdebriders ranging from the Xomed (Jacksonville, FL) Straight Shot/4.0-mm blade (147 g/min); the ESSential Shaver (Smith & Nephew, Memphis, TN)/4.0-mm blade (99 g/min), the Linvatec (Largo, FL)/4.2-mm blade and Dyonics (Burscheid, Germany)/3.5-mm blade and Wizard Plus/4.0-mm blade (range 43 to 46 g/min), followed by the Hummer Il (Stryker, Santa Clara, CA) 4.0-mm blade (22.5 g/min), and finally the Xomed Wizard Plus/3.5-mm blade at 16 g/min. The Xomed Straight Shot/4.0 blade was statistically superior to all other microdebriders in efficiency of aspiration in the firm tissue model. All microdebriders were able to abrade a “bony” spicule and intact “dura,” whereas. none could abrade intact “bone,” Conclusions: Significant differences exist among the various microdebriders in this standardized model of efficiency of aspiration. Additional clinical factors including cost, safety, ease of use, and adaptability should also be considered in the choice of a microdebrider.

8] Phosphofructokinase from oyster adductor muscle

Publisher Summary This chapter describes an assay method and the purification of phosphofructokinase from oyster adductor muscle and describes some of its properties. In oyster adductor muscle, phosphofructokinase (PFK) is closely regulated by the adenylates, arginine phosphate, and pH and is a key site controlling carbon flux during the aerobic–anaerobic transition. This purification is relatively simple to perform and has a high yield. Sufficient purified PFK for several thousand assays can be obtained from the muscle of a single oyster using this purification procedure. The purification scheme does not alter any of the key kinetic parameters of oyster muscle PFK compared to the crude preparation, suggesting that the enzyme is unaltered by purification itself. Other species of the genus Crassostrea have similar activities of PFK in the adductor muscle, and these, along with other oyster genera, may be suitable for use in the purification procedure described in the chapter.

Enzymes in facultative anaerobiosis of molluscs-I. Malic enzyme of oyster adductor muscle

1. 1. Malic enzyme (E.C. 1.1.1.40) in the adductor muscle of the Pacific oyster, Crossostrea gigas, occurs as a single electrophoretic species. 2. 2. Pyruvate saturation curves for the enzyme reaction are hyperbolic with an apparent K m for pyruvate of about 14–15 mM. Malate saturation curves are sigmoidal (Hill coefficient of 2·0) with S 0·5 values of 0·4–0·5 mM, indicating about a thirtyfold greater affinity of malic enzyme for malate than for pyruvate. 3. 3. In the forward direction, malic enzyme is not product-inhibited by pyruvate, but in contrast, in the backward direction the enzyme is potently product-inhibited by malate. 4. 4. NADPH and NADH also strongly inhibit enzyme activity in the direction of malate decarboxylation and the inhibition is competitive with respect to NADP. In terms of steepness of the response and the maximum inhibition attained, NADH is a more efficient inhibitor of the enzyme at pH values above neutrality. Acidification in effect leads to a loss of this regulatory characteristic. 5. 5. From these studies it is concluded that in vivo malic enzyme functions mainly in the malate → pyruvate direction and that its activity is regulated by the pH and the redox potential of the cell. 6. 6. The metabolic functions of malic enzyme in the overall anaerobic metabolism of oyster muscle are briefly discussed.

Separation of thick and thin myofilaments

Methods have been developed for separating the thin myofilaments from the thick ones in two molluscan muscles, the opaque adductor of the oyster, and the crossstriated adductor of Pecten. The thick filaments of these muscles have also been obtained with only a small contamination by thin ones. The media used in all procedures were designed to keep the filaments intact. Either differential centrifugation or zone velocity sedimentation on sucrose or glycerol density-gradients may be used; the latter method promises to be more generally useful. The sedimentation coefficients of these natural myofilaments (as measured under the conditions of the experiments) are: $ ̃ 34 s and $ ̃ 50 s for the thin filaments from the oyster muscle; $ ̃ 33 s for the thin filaments and $ ̃ 300 s for the thick filaments from the Pecten muscle. The S-value for the thick filaments from the oyster muscle is too large to be measured. Both myosin and paramyosin were found in the thick filaments of the oyster muscle and the Pecten muscle. Attempts to separate the thick and thin filaments of glycerol-extracted rabbit psoas muscle are also described; the problems involved are discussed.

X-ray diffraction patterns of α-fibrous proteins

A method is described which enables allowance to be made for the effect of surrounding material on the Fourier transform of a coiled coil. Using this method, distributions of intensity on the equator and near-equatorial layer lines are calculated for the wet and dry states, and compared with the observed distributions in oyster muscle, porcupine quill, rabbit psoas muscle and tropomyosin.

水産動物肉に関する研究-XXXV

Among various species of shellfish, one group changes its flavor depending on season. For instance, the common oyster, Ostrea lapérousei SCHRENCK, is more flavorous in winter than in its spawning months, June to September. The other, e. g., the short necked clam, Venerupis semidecussata (REEVE), shows little change throughout the year. Chemical constituents affecting the flavor most were reported to be monoamino nitrogen extractives-particularly glycine. The present work was, therefore, undertaken to confirm the general knowledge of palatability of the two groups of shellfish by comparing seasonal levels of their nitrogens extracted from materials listed in Table 1. The following are evident from the analytical results indicated in Table 2 to 5. 1) The oyster has low amounts of glycogen and extractive nitrogens with an increase of moisture in summer. In comparison with the other species of shellfish under study, extractive nitrogens of the oyster is abundant for total nitrogen; the amount of monoamino nitrogen (MAN) and the ratio of MAN to monoamino fraction nitrogen (MFN) are also fairly large. In summer, however, the MAN content and the ratio MAN/MFN fall from the levels in winter. The evidences explain the reason why the oyster muscle is less palatable in the spawning summer than in winter. 2) The short necked clam also has a large amount of extractive nitrogens. In this species, however, no remarkable variations have been observed in the quantity of either extractive nitrogens or general constituents. The shellfish is known to spawn not only in both spring and autumn but perhaps in summer as well. Such ecological characteristics would possibly minimize effects of spawning exhausion upon the muscle properties, which could in turn retain the meat flavor nearly constant all the seasons. 3) The brackish clam and the sea mussel, Mytilus crassitesta LISCHKE, scarecely vary their chemical components from season to season. The findings have made it doubtful if they really have high time of their flavor as said to do. 4) Extractive nitrogens in the brackish clam, Corbicula leana (PRIME), was found as low as that of a freshwater snail, Cipangopaludina malleata (REEVE) reported previously. A possible inference from this association is that low level of extractive nitrogens is a common feature of shellfish living outside the marine environments.

The structure of the muscle fibres in the translucent part of the adductor of the oyster Crassostrea angulata

The arrangement of the protein filaments and other details of the ultrastructure of the con­tractile apparatus have been studied by methods which include the examination of thin sections in the electron microscope. The results help towards a better understanding of three general problems: the reasons why some muscles appear striated and others smooth; the mechanism of contraction in muscles which are not cross-striated; and the mechanism by which certain muscles of molluscs can maintain a high level of tension for long periods without fatigue. The filaments are of two kinds, thick paramyosin filaments, and much thinner filaments which very probably contain mainly actin. Both are short, relative to the length of the fibre, lie parallel to the fibre axis, and are grouped into separate arrays which alternate with each other along the length of the fibre. The arrays partly overlap, and in the regions of overlap each thick filament is surrounded by twelve thin ones, and each thin filament is usually ‘shared' by two thick ones. The regions of the fibre where the arrays of thin filaments are exposed are identified as I -bands, the intervening regions (arrays of paramyosin filaments partly over­-lapping with arrays of thin filaments) as A -bands. The relative positions of the arrays change with the length of the muscle: the extent of overlap in the A -bands increases as the muscle shortens and decreases on stretching. Thus the muscle shortens by a sliding filament mechanism. Although the muscle is identified as a striated muscle because it has A - and I -bands, it differs from cross -striated muscles in two respects. In the first place, the bands lie at a small angle (about 10°) to the fibre axis, and are arranged helically around the outer part of the fibre, giving rise to the ‘double-oblique striation’ visible in the light microscope; more­ over, the bands branch and anastomose with each other in the core of the fibre. In the second place, there are no Z -lines, but in the planes where Z -lines would be expected, discrete dense-bodies are present. Similar dense-bodies occur in many smooth muscles, for example, in the mammalian uterus (Mark 1956; Shoenberg 1958), and in the anterior byssus retractor of Mytilus (Hanson &amp; Lowy 1959 a ). The contractile apparatus of the latter closely resembles that of the oyster muscle in many respects, but the filaments are not clearly grouped into separate arrays. This feature, the presence or absence of segregated arrays of filaments, could serve as the main criterion for distinguishing striated from smooth muscles. Where the arrays of thick and thin filaments overlap in the A -bands, the two kinds of filaments appear to be cross-linked by means of transverse projections which belong to the thick filaments. The view is put forward that the paramyosin filaments are comparable to the myosin-containing filaments of the cross-striated muscles of vertebrates, and that the cross-links in the oyster muscle are comparable to actin-myosin links. The role which paramyosin filaments play in the mechanism by which certain muscles of molluscs maintain tension very economically is also discussed. The results described in this paper support the hypothesis (Lowy &amp; Millman 1959 b , 1960) that tension is held by cross-links in a sliding filament contractile mechanism and that the economy of the system is due to a low rate of detachment of these cross-links. The alternative ‘catch’-mechanism hypothesis (Johnson, Kahn &amp; Szent-Györgyi 1959; Johnson &amp; Szent-Györgyi 1959; Rüegg 1959) which supposes that tension is maintained by some change of state of the protein within a paramyosin system, is difficult to reconcile with the present findings. Structures which resemble the ‘dyads’ of the cross-striated muscles of vertebrates have been found beneath the cell membrane. Their possible function in the intracellular trans­mission of stimuli is discussed in view of the fact that the fibres of the oyster muscle are only about 2 μ thick.

The Effect of Narcotics on the Endogenous Respiration and Succinate Oxidation in Oyster Muscle

The action of the following compounds on homogenates of the adductor muscles ofSaxostrea commercialiswas studied: urethane, phenyl urethane, chloral hydrate, salicylic acid, morphine, caffeine, barbitone, benzoic acid, salicylamide and benzamide.It was found that, except for 0·05 M urethane, the endogenous oxygen consumption was reduced by all these compounds when present in concentrations ranging from o·001 to 0·05M. The oxidation of succinic acid was partially inhibited by these substances.These findings are discussed in relation to similar studies on other tissues.

The Succinoxidase System in Oyster Muscle

ABSTRACT The importance of the role which the C4-dicarboxylic acids play in tissue respiration was pointed out by Szent-Györgyi in 1937. It is now known that succinic dehydrogenase is one of the few dehydrogenases which react directly with the cytochromes, and the ‘succinoxidase’ system has been investigated in a large number of vertebrate tissues. The action of succinate on the oxygen uptake of a few invertebrate tissues has been studied, but no detailed consideration has been given to the possible occurrence of a succinoxidase system. This system becomes especially important in view of the varied response of such tissues to agents like cyanide and azide, which have a marked effect on cytochrome oxidase.