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1.
The structural stability of fish myosin depends upon species and temperatures of water in which fish live. Primary, secondary, and quaternary structures of myosin heavy chain (MyHC) from three species of fish living at different temperature ranges have been compared with those of rabbit MyHC in order to investigate the differences in stability. Primary structure of MyHC, although being accessible for warm-water and cold-water fish (carp and walleye pollack), was not available in previous for tropical-water fish literature; so in this study primary structure of MyHC of the tropical-water fish amberjack has been determined by cloning and sequencing its cDNA. The MyHC has 1938 amino acid residues (AA), which are almost as much as as those of carp and walleye pollack. The amberjack MyHC is 91–95% homologous with other fish and rabbit MyHCs. There is a discernible difference between animal species with stable myosin rod (amberjack, carp, and rabbit) and walleye pollack with unstable rod. Stable rod species have a high probability of forming coiled-coil around the COOH-terminal end of the rod, while the pollack has a low coiled-coil formation probability. In addition, the average scores of the coiled-coil for myosin rod were rabbit (1.738) > amberjack (1.691) > carp (1.680) > walleye pollack (1.674) which correlated exactly with the observed stability. The results suggest that coiled-coil forming ability, particularly around the COOH-terminal end, directs structural stability of fish myosin rod.  相似文献   

2.
ABSTRACT:   Enzymatic and structural properties of white croaker fast skeletal muscle myosin were determined and compared with those of walleye pollack counterpart. Ca2+-ATPase activity of white croaker myosin was decreased to approximately 70% of the original activity during 1 day of storage at 0°C and pH 7.0 in 0.5 M KCl and 0.1 mM dithiothreitol, whereas that of walleye pollack was decreased to approximately 20% under the same condition. The activation energy ( E a) for inactivation of white croaker myosin calculated by the Arrhenius plot for inactivation rate constant (KD) was 1.2-fold higher than that of walleye pollack. While Ca2+-ATPase showed a similar KCl-dependency for the two species, the maximal activity was observed at pH 6.2 and 6.3 for white croaker and walleye pollack, respectively. Actin-activated myosin Mg2+-ATPase activity of white croaker was approximately half that of walleye pollack at 0.05 M KCl and pH 7.0, although the two myosins showed a similar affinity to F-actin with K m of 1.7 and 1.4, respectively. Limited proteolysis with α-chymotrypsin cleaved heat-denatured white croaker myosin mainly at heavy meromyosin/light meromyosin (HMM/LMM) junction, whereas walleye pollack myosin was cleaved at several sites in LMM as well as at the HMM/LMM junction.  相似文献   

3.
ABSTRACT:   The effect of salt concentration on the thermal denaturation profile of myosin in walleye pollack and carp myofibrils was compared by studying the subfragment-1 (S-1) and rod denaturation rates upon heating. Species-specific denaturation mode observed at 0.1 M KCl was no longer detected when samples were heated above 0.5 M KCl, where S-1 and rod denaturation rates were identical to each other. As the heating of the chymotryptic digest of myofibril formed practically no rod aggregates, S-1 denaturation in a form of myosin was the rate limiting step for rod aggregate formation. As the aggregate formation by rod was remarkably suppressed by lowering the temperature, the free movement of myosin tail upon heating was suggested to play an important role in the rod aggregate formation in a high salt medium.  相似文献   

4.
ABSTRACT:   Aspolin is a polyaspartic acid-like protein, which is originally isolated from walleye pollack Theragra chalcogramma muscle as trimethylamine- N -oxide (TMAO) demethylase. Although carp Cyprinus carpio muscle contains a trace amount of the enzyme substrate, TMAO, aspolin can be extracted and purified by acid treatment, successive chromatographies and polyacrylamide gel electrophoresis, and has twice the amount of that in walleye pollack muscle. Carp aspolin showed a low enzymatic activity in the presence of Fe2+ and reductants, and its Km value (100 mM) to TMAO was extremely high. It was a thermostable protein and had an unfolded conformation. The amino acid sequence of carp aspolin 1 deduced from cDNA revealed that it contained a long Asp polymer, an uninterrupted stretch of 138 Asp residues, followed by four amino acid residues, His-Glu-Glu-Leu, in C-terminus. The chain length was shorter by 42 Asp residues than that of its walleye pollack counterpart.  相似文献   

5.
ABSTRACT: The effect of pH on thermal gelation and transglutaminase (TGase; EC2.3.2.13)-induced suwari (setting) of surimi and actomyosin pastes was investigated. A strong and elastic gel was produced from walleye pollack surimi paste at pH 7.0 in the presence of Ca2+ using a two-step heating method. In contrast, walleye pollack actomyosin paste formed a weak gel under the same conditions as a result of the low concentration of endogenous TGase. In the presence of EGTA [ethyleneglycol bis(2-aminoethylether) tetraacetic acid], weak gels were formed at pH values of 7.0 and 6.0. Non-proteolytic modori (gel weakening) occurred extensively in the course of actomyosin gelation, but not in surimi gelation. Maximum TGase-induced myosin heavy chain cross-linking was observed at a slightly higher pH of 7.5 than at the optimal pH of endogenous TGase activity; the difference being derived from different substrates. Gelation of carp actomyosin paste at pH values of 5.5, 6.0, 6.5 and 7.0 was monitored by measuring storage modulus (G') and loss modulus (G"). A weak gel was formed at all pH values, but a slightly rigid and less elastic gel was obtained at lower pH values. The addition of microbial TGase (MTGase) formed strong elastic gels at pH 7.0 and 6.5. MTGase cross-linked myosin heavy chains even at pH 5.5, but contributed neither to suwari response nor strong gel formation. Overall, results suggest that the optimal pH for the gelation of surimi paste from easy-setting fish species is a compromise between the pH-optima of TGase activity and of preferable actomyosin conformation for myosin cross-linking.  相似文献   

6.
Vitellogenin (VTG), the egg yolk precursor protein, was purified from plasma of estradiol-3-benzoate (E2B)-treated male shorthead redhorse (Moxostoma macrolepidotum) and immature copper redhorse (Moxostoma hubbsi) by a two-step chromatographic procedure without precipitation. Intact VTGs appeared as dimers with apparent molecular masses, determined by gel filtration, of ∼425 kDa (copper redhorse) and ∼450 kDa (shorthead redhorse). In native polyacrylamide gel electrophoresis (PAGE), dimeric redhorse VTGs appeared as a 520 kDa band. Both VTGs were reduced to a single monomer of ∼150 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and nonreducing conditions, indicating that monomers are not linked by disulfide bonds in the dimer form. The purified proteins were characterized as phospholipoglycoproteins. Isoelectric focusing of both VTGs revealed components with isoelectric points ranging from 5.3 to 6.0, suggesting charge heterogeneity. The amino acid composition of both VTGs contains a high proportion of nonpolar amino acids and was similar to those of other teleosts. An antibody developed against carp (Cyprinus carpio) VTG showed cross-reactivity with VTG from both redhorse species. Using this antibody, VTG was detected in plasma and surface mucus of E2B-treated redhorse. This is the most extensive report on purification and characterization of vitellogenin from catostomidid species.  相似文献   

7.
The effects of setting (suwari) at around 40 °C on the breaking strength and breaking strain rate of thermal gels treated at 85 °C for 20 min during the following processing step were examined in association with the polymerization and degradation of myosin heavy chains (MHCs) for surimi prepared from white croaker, walleye pollack and deepsea bonefish. In the case of white croaker and walleye pollack, maximum values of breaking strength and breaking strain rate were obtained after suwari at 30–40 °C for both 30 and 60 min, at which temperature MHCs were polymerized. In comparison, these textual properties of the thermal gels decreased in surimi prepared from deepsea bonefish after suwari at around 38 °C for 30 min and at around 32 °C for 60 min, with concomitant degradation products of MHC. The textual properties of deepsea bonefish after suwari at temperatures >45 °C tended to be almost the same as those after suwari at temperatures of <30 °C, where neither polymerization nor degradation of MHC was observed.  相似文献   

8.
9.
TOMOYUKI  HIGUCHI  TAKAO  OJIMA  KIYOYOSHI  NISHITA 《Fisheries Science》2002,68(5):1145-1150
Heat-induced structural changes and aggregation properties of walleye pollack myosin, light meromyosin (LMM) and heavy meromyosin (HMM) were investigated. According to the circular dichroism (CD) measurement, the α-helix content of the pollack myosin and LMM were estimated to be 72% and 90% at 5°C but decreased to 22% and 21% by increasing the temperature to 60°C with two transitions at 35°C and 50°C, respectively. In contrast, that of HMM decreased gradually from 37% to 33% by increasing the temperature from 5°C to 40°C, and decreased steeply to 20% above 50°C. These results indicate that the decrease in the α-helix content in the myosin molecule upon heating was attributable mainly to the decrease in the α-helix content in the LMM region. In contrast, 1-anilinonaphthalene-8-sulfonate (ANS) fluorescence and light scattering intensity of both myosin and HMM were remarkably increased above 25°C and 35°C, respectively, while those of LMM showed only a slight change even above 60°C. Although LMM alone formed no aggregates detectable by the light scattering measurement, it formed coprecipitates with myosin but not with HMM upon heating at 40°C for 10 min. These facts suggest that LMM bind to the LMM region of the myosin. Further, it was found that myosin gel formed in a test tube by the same heating conditions was significantly weakened by coexistence of LMM. These results suggest that the association of the LMM region of myosin molecules is essential for the heat-induced gelation of myosin.  相似文献   

10.
ABSTRACT:   The complete cDNA sequences encoding predominant types of myosin heavy chain (MYH) in the fast skeletal muscle were determined for brushtooth lizardfish Saurida undosquamis and wanieso lizardfish S. wanieso , which are used as materials for preparing high-quality surimi-based products. The cDNA consisted of 5973 and 5987 bp, respectively, and both encompassed an open reading frame encoding a polypeptide of 1936 amino acid residues. Brushtooth and wanieso lizardfish MYH showed the amino acid sequence identity of 92–93% to white croaker MYH, which was higher than that of 90% to walleye pollack MYH. The putative binding sites for ATP, actin, and regulatory and essential light chains in the subfragment-1 region of brushtooth lizardfish MYH exhibited a high identity with white croaker counterparts as well as the sequences of subfragment-2 and light meromyosin. In contrast, phylogenetic tree, constructed by the neighbor-joining method based on mitochondrial 16S rRNA gene, revealed that the two lizardfish species formed a cluster with walleye pollack, which was paraphyletic with white croaker. Therefore, a good reputation for lizardfish and white croaker to have a high thermal-gel forming ability seemed to be reflected by MYH rather than biological similarity as revealed by the mitochondrial 16S rRNA gene.  相似文献   

11.
12.
ABSTRACT: To clarify the contribution of polymerization of myosin heavy chain (MHC) by disulfide bonding to increased gel strength of cooked gel via preheating, the pastes of walleye pollack surimi (SS and C grades) were preheated at 25°C and 40°C for a variety of hours prior to heating at 80°C for 20 min. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns of cooked gels were analyzed with and without reducing the samples, which were solubilized in 8 M urea–2% SDS solution. The formation of polymers by disulfide bonding in cooked gels was almost constant in each of the SS and C grade surimi gels despite the period of preheating. Therefore, it was suggested that polymerization by disulfide bonding occurred during cooking at 80°C and not during preheating.  相似文献   

13.
Walleye Sander vitreus Mitchill have been progressively raised in hatcheries to larger sizes under the paradigm that larger stocked fish have higher survival. However, extended time in hatcheries may result in domestication, with stocked individuals lacking behaviours that promote survival. The objective of this study was to evaluate behaviour and survival of wild versus stocked fingerling (>200 mm) walleye in two Iowa reservoirs. Radio telemetry was used to evaluate walleye movement rates, depth use, home range size, habitat selection and apparent survival. Depth use increased with days since stocking and varied between lake‐years but was similar between walleye groups. Daily movement rates varied by the interaction between group and day, with rates declining through time. Home ranges did not differ between groups but were significantly greater in Big Creek than Brushy Creek. Walleye in both lakes generally used habitat in proportion to availability, with few differences between groups detected. Weekly apparent survival ranged from 0.948 to 1.000, varied across lakes, years and seasons, and was higher for stocked than wild walleye in Big Creek but not Brushy Creek. The results indicate that hatchery‐reared fingerling walleye behave similar to but can have higher survival than wild fish, suggesting that domestication may not be occurring and that stocking autumn fingerling walleye may help supplement year‐class strength.  相似文献   

14.
Abstract Predation is an important force structuring aquatic communities, but predator–prey interactions are complex and regulated by multiple factors. Invasive fishes may interact with native fishes to alter predator–prey preferences and community dynamics. For example, common carp, Cyprinus carpio L., is an invasive species that can become abundant and negatively affect aquatic ecosystems. Juvenile common carp are occasionally found in predator diets, but predator preferences for common carp compared with alternative prey remains unknown. Prey selection and feeding behaviour of five piscivores (flathead catfish, Pylodictis olivaris (Rafinesque); largemouth bass, Micropterus salmoides (Lacepède); smallmouth bass, M. dolomieu Lacepède; walleye, Sander vitreus (Mitchill); and northern pike, Esox lucius L.) foraging on juvenile common carp and two alternative prey (fathead minnow, Pimephales promelas Rafinesque, and yellow perch, Perca flavescens Mitchill) at variable densities and habitats were evaluated. Common carp and fathead minnow were generally selected for or neutrally selected across predator species, habitat types and prey assemblages. By contrast, yellow perch was generally selected against. Common carp were easily captured but difficult to manipulate and ingest compared with other prey. These results reveal that common carp are vulnerable to a variety of predators, suggesting control of this detrimental invader may be possible through biomanipulation.  相似文献   

15.
Two cystatins (cst-I and cst-II) were purified from crucian carp eggs by acidification and subsequent ion exchange and molecular sieve chromatography. The molecular masses of cst-I and cst-II analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis were 11.9 and 14.4 kDa, respectively, under reducing conditions and 13.5 and 12.7 kDa, respectively, under non-reducing conditions. The cst-I and cst-II molecules were stable after 30 min of incubation at 60 and 50°C, respectively. There was no significant loss in the inhibitory activity of either cst in the pH range 4–11. These two cystatins were able to affect the proteolysis of papain, cathepsin L, and bromelain, but they were unable to inhibit cathepsin B and trypsin. The partial N-terminal amino acid sequences of both cst inhibitors were homologous and that of cst-I was recognized as NH2-AGIPGGLVDADINDADVQ. This latter fragment shared 88.9% identity to common carp cystatin and 44.4–55.6% to cystatins of other aquatic animals. Based on these results, we conclude that the two cst inhibitors are members of family II cystatin.  相似文献   

16.
17.
Determining the factors that influence recruitment to sequential ontogenetic stages is critical for understanding recruitment dynamics of fish and for effective management of sportfish, particularly in dynamic and unpredictable environments. We sampled walleye (Sander vitreus) and white bass (Morone chrysops) at 3 ontogenetic stages (age 0 during spring: ‘age‐0 larval’; age 0 during autumn: ‘age‐0 juvenile’; and age 1 during autumn: ‘age‐1 juvenile’) from 3 reservoirs. We developed multiple linear regression models to describe factors influencing age‐0 larval, age‐0 juvenile and age‐1 juvenile walleye and white bass abundance indices. Our models explained 40–80% (68 ± 9%; mean ± SE) and 71%–97% (81 ± 6%) of the variability in catch for walleye and white bass respectively. For walleye, gizzard shad were present in the candidate model sets for all three ontogenetic stages we assessed. For white bass, there was no unifying variable in all three stage‐specific candidate model sets, although walleye abundance was present in two of the three white bass candidate model sets. We were able to determine several factors affecting walleye and white bass year‐class strength at multiple ontogenetic stages; comprehensive analyses of factors influencing recruitment to multiple early ontogenetic stages are seemingly rare in the literature. Our models demonstrate the interdependency among early ontogenetic stages and the complexities involved with sportfish recruitment.  相似文献   

18.
Koi herpesvirus (KHV) causes a highly infectious disease afflicting common carp and koi, Cyprinus carpio L. Various molecular and antibody‐based detection methods have been used to elucidate the rapid attachment and dissemination of the virus throughout carp tissues, facilitating ongoing development of effective diagnostic approaches. In situ hybridization (ISH) was used here to determine the target tissues of KHV during very early infection, after infecting carp with a highly virulent KHV isolate. Analysis of paraffin‐embedded tissues (i.e. gills, skin, spleen, kidney, gut, liver and brain) during the first 8 h and following 10 days post‐infection (hpi; dpi) revealed positive signals in skin mucus, gills and gut sections after only 1 hpi. Respiratory epithelial cells were positive as early as 2 hpi. Viral DNA was also detected within blood vessels of various tissues early in the infection. Notable increases in signal abundance were observed in the gills and kidney between 5 and 10 dpi, and viral DNA was detected in all tissues except brain. This study suggests that the gills and gut play an important role in the early pathogenesis of this Alloherpesvirus, in addition to skin, and demonstrates ISH as a useful diagnostic tool for confirmation of acutely infected carp.  相似文献   

19.
Vitellogenin (Vtg) induction in carp (Cyprinus carpio) is a commonly used biomarker for oestrogenic contamination. However, the accurate quantification of Vtg was challenged because the easy degradation of Vtg standard would change the standard curves of the immunoassays. In this study, three yolk proteins were purified from carp ovarian extracts by a two‐step chromatographic method. The purified proteins were characterized as phospholipoglycoproteins with molecular weights of approximately 416, 398 and 383 kDa. In SDS‐PAGE, the purified proteins appeared as a major band of approximately 110 kDa and several faint bands. Based on these characteristics, purified proteins were identified as carp lipovitellin (Lv). Immunological analysis showed that anti‐Vtg antiserum reacted with the purified Lv. The results of stability analysis revealed that even heated at 60°C for 60 min, the electrophoretic patterns of carp Lv in native‐PAGE and SDS‐PAGE did not have a significant difference compared with the Lv solution stored at 4°C. Therefore, the purified carp Lv was confirmed to have similar immunogenicity with Vtg and possess exceptionally high stability, which would be helpful for the development of robust immunoassays for accurate quantification of carp Vtg.  相似文献   

20.
The effectiveness of an acoustic barrier to deter the movement of silver carp, Hypophthalmichthys molitrix (Valenciennes) and bighead carp, H. nobilis (Richardson) was evaluated. A pond (10 m × 5 m × 1.2 m) was divided in half by a concrete‐block barrier with a channel (1 m across) allowing fish access to each side. Underwater speakers were placed on each side of the barrier opening, and an outboard motor noise (broadband sound; 0.06–10 kHz) was broadcast to repel carp that approached within 1 m of the channel. Broadband sound was effective at reducing the number of successful crossings in schools of silver carp, bighead carp and a combined school. Repulsion rates were 82.5% (silver carp), 93.7% (bighead carp) and 90.5% (combined). This study demonstrates that broadband sound is effective in deterring carp and could be used as a deterrent in an integrated pest management system.  相似文献   

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