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1.
ABSTRACT: Incubation of squid mantle muscle homogenate caused a selective cleavage of myosin into heavy meromyosin (HMM) and light meromyosin (LMM). HMM was isolated from the incubated homogenate by using ammonium sulfate fractionation. The purified HMM retained two types of light chain components. Its Mg2+ -ATPase activity with or without F-actin showed a Ca-sensitivity. HMM was cleaved into subfragment-1 and subfragment-2 upon chymotryptic digestion with or without Ca2+ , possessing different light chain composition. Two types of light chain component were kept intact when digested in the presence of Ca2+ . Ca2+ stabilized HMM especially in a bound form to F-actin. 相似文献
2.
ABSTRACT: Nucleotides and Ca2+ binding to α-actin prepared from ordinary skeletal muscle of carp Cyprinus carpio was studied. When bound Ca2+ was removed with ethylenediaminetetraacetic acid, carp α-actin denatured more rapidly than chicken α-actin. Kinetic studies of the denaturation process showed that in the absence of divalent cations, the binding constants of ATP to carp and chicken actin were 5.0 × 104 /M and 1.2 × 105 /M, respectively. Competitive binding of Ca2+ between actin and 8-amino-2-[(2-amino-5-methylphenoxy)methyl]-6-methoxyquinoline-N,N,N',N'-tetraacetic acid (Quin 2) showed that affinity of Ca2+ for carp actin was also lower than that for chicken actin by a factor of 1.6. These results indicated that carp actin could relatively easily denature due to the low affinities of these ligands. Enthalpy changes upon ATP binding to carp and chicken actin were −65 kJ/mol and −110 kJ/mol, respectively. Thermodynamic analyses of our results revealed that the entropy change associated with ATP binding to carp actin was significantly smaller than that to chicken actin, suggesting that structural stabilization upon ATP binding was less effective in carp actin. 相似文献
3.
Thermal denaturation and autolysis profiles of myofibrillar proteins of mantle muscle of jumbo squid Docidicus gigas 总被引:1,自引:0,他引:1
KUNIHIKO KONNO CHO YOUNG-JE TAKEYA YOSHIOKA PARK SHINHO NOBUO SEKI 《Fisheries Science》2003,69(1):204-209
ABSTRACT: Jumbo squid was very similar to Japanese common squid in terms of myofibrillar Ca2+ -, Mg2+ - and K+ (EDTA)-ATPase activities. Myofibrils of jumbo squid were significantly stabilized upon addition of Ca2+ and destabilized by increasing KCl concentration for heating. Incubation of muscle homogenate of jumbo squid induced a selective cleavage of myosin into two major fragments and the cleavage was inhibited by EDTA. Autolysis was prominent at and above 0.3 M NaCl where myosin filaments dissolve. The enzyme involved in the autolysis was proved to be unstable showing maximal autolysis rate at 25°C. Washing the homogenate partially reduced the autolysis activity. 相似文献
4.
ABSTRACT: The thermal stability of carp G-actin was investigated by monitoring loss of actin polymerization ability. To determine the amount of native actin remaining after heat treatment, actin was labeled with a fluorescence reagent, N-(1-pyrene)iodoacetamide. The loss of polymerization ability of carp actin during heat treatment, at between 45 and 55°C, occurred faster than that of chicken actin. The inactivation rate was influenced by concentrations of ATP and Ca2+ in solution. With the increase of Ca2+ concentration, the inactivation of carp actin was markedly suppressed. Furthermore, the activation energy of the inactivation of carp actin obtained from an Arrhenius plot was similar to that of chicken actin. These results indicated that the thermal instability of carp G-actin was due to the low affinites of ATP and Ca2+ for carp actin described in a previous report. 相似文献
5.
ABSTRACT: To examine the involvement of chloride cells in the uptake of Ca2+ in freshwater (FW) killifish, chloride cell morphology was compared in fish acclimated to different defined FW environments with Ca2+ concentrations of either 0.1 mM, 0.5 mM, or 2.5 mM. Numerous chloride cells were detected in whole-mount preparations of the gill filaments, which were stained with an antiserum specific for Na+ , K+ -ATPase. Chloride cells, located mostly on the afferent–vascular edge of the filaments, were larger at lower Ca2+ concentrations. Electron microscopic observations showed that in the 0.1 mM and 0.5 mM Ca2+ experimental groups, the apical membrane of chloride cells were flat or slightly projecting and equipped with numerous microvilli. In the 2.5 mM Ca2+ group, some chloride cells formed an apical pit, whereas other cells were similar to those observed in the 0.1 mM and 0.5 mM Ca2+ groups. Plasma osmolality decreased with decreasing ambient Ca2+ concentration, suggesting that environmental Ca2+ affects the permeability of the body surfaces. Gill Na+ , K+ -ATPase activity in the 0.1 mM and 0.5 mM Ca2+ groups were significantly higher than that in the 2.5 mM Ca2+ group, implying the involvement of the Na+ –Ca2+ exchanger in Ca2+ uptake in the gills. These findings suggest that chloride cells function as the site for Ca2+ uptake in killifish acclimated to low Ca2+ environments. 相似文献
6.
ABSTRACT: This study incorporated the 43 kDa Zn-binding membrane protein isolated from common carp into liposome. The specificity and strength of the binding of 65 Zn to the 43 kDa protein-liposomes, and the binding of the 65 Zn-labeled 43 kDa protein-liposomes to laminin were studied. It was found that 65 Zn was bound to the external side of the 43 kDa protein-liposomes. Specific binding of 65 Zn to the protein-liposomes was detected. The binding parameter of Zn to the protein was found to be: maximum binding site (Nmax ), 76.7 pmole/µg protein (approx. 3 mole of Zn2+ /mole); and equilibrium dissociation constant (Kd), 0.19 µM. Of the cations introduced (Ca2+ , Cd2+ ,Co2+ , Cr2+ , Cu2+ , Fe2+ , Hg2+ , Mg2+ , Mn2+ , Ni2+ , Pb2+ ), only Co2+ competed significantly with Zn. The protein-liposomes were also found to bind specifically to laminin with a Nmax of 1.1 pmole/µg laminin, and Kd of 4.79 µM. No significant protein-liposome binding occurred to other extracellular matrix proteins (fibronectin, fibrinogen or vitronectin). Furthermore, the binding was specifically inhibited by the Arg-Gly-Asp (RGD) peptide or GRGDSPG, while two other analogs (GRGESPG and GRADSPG) were without effect. 相似文献
7.
ABSTRACT: Amylase, with MW of 59 kDa, was purified from small abalone Haliotis sieboldii by ammonium sulfate fractionation, CM Sepharose Fast Flow and Sephacryl S-100 HR chromatographies. The optimal pH and temperature of purified amylase were 6.0 and 37°C, respectively. The purified enzyme was stable at pH 6.0–8.0 and low temperatures. It was activated by Ba2+ , Mg2+ , Ca2+ , Co2+ , Ni2+ , Mn2+ , K+ , Ag+ , Na+ and Li+ , but completely or partially inhibited by Al3+ , Cu2+ , Cd2+ , Hg2+ and Zn2+ . EDTA could completely inhibit, while iodoacetamide, N-ethylmaleimide and urea partially inhibit the purified amylase. According to the digestion mode of various polysaccharides, the purified enzyme was considered to be an α-amylase. 相似文献
8.
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
9.
Satoru TANAKA Tomoko UTOH Yoshiaki YAMADA Noriyuki HORIE Akihiro OKAMURA Atsushi AKAZAWA Naomi MIKAWA Hideo P OKA Hisashi KUROKURA 《Fisheries Science》2004,70(5):780-787
ABSTRACT: In order to find out the role of sodium bicarbonate (NaHCO3 ) on the initiation of sperm motility in the Japanese eel Anguilla japonica , interactions were investigated between NaHCO3 and various reagents (K+ channel blocker 4-aminopyridine [4-AP], ammonium chloride [NH4 Cl], sodium acetate and calcium chloride [CaCl2 ]) that could regulate internal factors (intracellular K+ , intracellular pH [[pH]i ] and intracellular Ca2+ ) in sperm motility. Contradictory effects of NaHCO3 were observed (i.e. an inhibitory effect when 4-AP was absent and a promoting effect when 4-AP was present). Sodium bicarbonate inhibited the initiation of sperm motility in the Japanese eel. However, NaHCO3 restored the motility of immotile sperm that 4-AP inhibited. The inhibitory effect of NaHCO3 disappeared with the addition of NH4 Cl, which raised [pH]i , but the promoting effect was not affected by [pH]i . Although NaHCO3 recovered motility in the presence of 4-AP, this recovery was also observed with the addition of CaCl2 instead of NaHCO3 . In the initiation of sperm motility in the Japanese eel, two roles for NaHCO3 are suggested: an inhibitory role relating to the regulation of [pH]i and a promoting role relating to the uptake of another initiation factor, which could be Ca2+ . 相似文献
10.
Effects of urea and trimethylamine-N-oxide on ATPase of requiem shark myofibril and its constituents
Satoshi Kanoh Masaya Kitamura Yuta Horie Yuuki Kasama Eiji Niwa 《Fisheries Science》2001,67(5):943-947
ABSTRACT: The effects of trimethylamine- N -oxide (TMAO) on the urea-resistibility of requiem shark myofibrils were investigated, using Ca2+ - and Mg2+ -ATPase activities as a parameter. Both activities were hardly changed or activated up to 0.6 M urea. In contrast, the two activities both decreased to less than 50% in the presence of TMAO up to 0.5 M. When measured at a 2 : 1 molar ratio of urea and TMAO, Ca2+ - and Mg2+ -ATPase activities were similar to those in the presence of TMAO alone, indicating that TMAO reduced the urea-resistibility of myofibrils. Myosin, the most abundant protein in myofibrils, from requiem shark exhibited the effects of urea and TMAO on its Ca2+ -ATPase activity, which was primarily similar to those of myofibrils. However, Ca2+ -ATPase activities in the coexistence of urea and TMAO for actomyosin reconstituted from requiem shark myosin and chicken F-actin were approximately average of those measured independently in the presence of either urea or TMAO alone. Carp myofibrils, reconstituted actomyosin and myosin, which were used as teleost references, all showed a tendency in the effects of urea and TMAO on Ca2+ -ATPase activities that was similar to those of requiem shark counterparts. 相似文献
11.
ABSTRACT: The present study used squid gill as a source of transglutaminase (TGase) because it has extremely high TGase activity compared with other tissues. The enzyme was purified using successive chromatographies of Sephacryl S-300 and hydroxyapatite columns. The yield and purification-fold of the enzymatic activity was 12.6% and 14.1-fold, respectively. The molecular mass of the purified enzyme was estimated to be 94 kDa by using sodium dodecylsulfate–polyacrylamide gel electrophoresis analysis. Enzyme activity was enhanced 15-fold with an increase in NaCl concentration. Although the activity was dependent on Ca2+ concentration, it was not sufficiently activated even by 50 mM CaCl2 in the absence of NaCl, but could be fully activated with 10 mM CaCl2 in 0.7 M NaCl. However, in the absence of substrates, the enzyme was rapidly inactivated. The pH and temperature optima of the enzyme were approximately pH 8.0 and 20°C, respectively. It was stable in the absence of Ca2+ at pH 7.5–9.0 and had a rate constant (K D ) of 1.6 × 10–5 s–1 for thermal inactivation at 50°C. These results in which squid gill TGase could be activated at higher concentrations of Ca2+ and NaCl than at a physiological concentration, suggest that contact with seawater or body fluid seems to activate the enzyme if the tissue is disrupted. 相似文献
12.
13.
Mohammed Abdullah Al-Dohail Roshada Hashim & Mohammed Aliyu-Paiko 《Aquaculture Research》2009,40(14):1642-1652
This experiment was carried out to evaluate the effects of the probiotic, Lactobacillus acidophilus , on the growth performance, haematology parameters and immunoglobulin concentration in African catfish Clarias gariepinus fingerling. Two experimental diets were formulated to contain 35 g kg−1 crude protein and 10 g kg−1 lipids accordingly and fed three times daily for 12 weeks to 25 C. gariepinus fingerlings per fibreglass tank in 12 replicates each. The control diet was prepared with no probiotic supplementation whereas the second diet was prepared supplemented with a probiotic, L. acidophilus , containing about 3.01 × 107 colonies/g of diet. The results show that growth performance [specific growth rate (SGR) and relative growth rate (RGR)], nutrient utilization [protein efficiency ratio (PER) and feed conversion ratio (FCR)] and survival were significantly ( P <0.05) higher in fish maintained on the probiotic-supplemented diet compared with those on the control diet. Haematology parameters (packed cell volume, haemoglobin, erythrocyte sedimentation rate, red blood cell and white blood cell, total serum protein, Ca2+ , Mg2+ , Cl− , glucose and cholesterol) and total immunoglobulin concentrations were also significantly better in fish fed the probiotic-supplemented diet than in the control. Although the water quality parameters monitored were better in the fish fed the probiotic-supplemented diet than in the control, the parameters were not significantly different ( P >0.05). From the results of this experiment, we conclude that L. acidophilus can be used as a probiotic agent in African catfish culture, to enhance fish health, survival and better feed efficiency and growth performance. 相似文献
14.
The influence of dietary cation–anion difference (CAD, Na+ + K+ – Cl– , mEq kg–1 ) on energy metabolism and nitrogen losses in juvenile African catfish Clarias gariepinus (Burchell) was examined in fish exposed to different dietary CAD levels (–146, 116, 497, 713 and 828 mEq kg–1 diet). The experiment was conducted in open circuit balance respiration chambers over a 3-week period. Five 24-h monitoring periods were carried out at 3-day intervals during the experimental period with O2 consumption, ammonia and nitrate + nitrite (NOx ) and CO2 production being measured at 5-min intervals for each chamber. The negative dietary CAD (–146 mEq kg–1 ) resulted in the highest energy expenditures (83 kJ kg–0.8 · d–1 ). With increasing dietary CAD levels, heat loss gradually decreased to minimum values of 56 kJ kg–0.8 day–1 at a dietary CAD level of 713 mEq kg–1 . Consequently, metabolizable energy utilization efficiency (MEU, percentage of retained energy over metabolizable energy) quadratically ( P < 0.05) increased and reached a maximum at a dietary CAD of 713 mEq kg–1 . 相似文献
15.
ABSTRACT: Suppressive effects of non-ionic (sorbitol, maltose, and trehalose) and ionic (Na-glutamate, Na-acetate, Na-sulfate, and ammonium sulfate) compounds on the thermal inactivation of myosin subframgent-1 (S-1) and myofibril Ca2+ -ATPase were compared. All compounds suppressed S-1 denaturation. When myofibrils were used (at 0.1 M KCl), sugars and sugar alcohol (non-ionic compounds) suppressed denaturation similar to S-1, while Na-glutamate, Na-acetate, and Na-sulfate weakly suppressed them. Ammonium sulfate accelerated denaturation, but suppressed denaturation when heated in 2 M KCl, at which myosin lost protection by F-actin. It was thus concluded that ionic compounds affected the denaturation of myofibrils in two ways; suppression as established with S-1, and acceleration as a result of loss of protection by F-actin caused by increase in ionic strength. 相似文献
16.
The influence of different levels of dietary vitamin E on sea bass Dicentrarchus labrax flesh quality 总被引:3,自引:0,他引:3
Sea bass Dicentrarchus labrax fillet quality was investigated after feeding with four diets (A, B, C or D) containing different levels of dietary vitamin E (139 mg kg–1 , 254 mg kg–1 , 493 mg kg–1 and 942 mg kg–1 , respectively). Six-hundred and eighty fish (mean initial weight 208 g) were equally divided into four 20 m3 tanks and fed for 87 days. Filtered seawater with a temperature ranging from 18.2 to 26.3 °C was supplied continuously. At the end of the experiment, fish were stored at 1 °C for 12 days. At one, three, six, nine and 12 days, 20 fish per group were processed for proximate composition, vitamin E and induced thiobarbituric acid reactive substances (TBARs) analyses. No significant differences in proximate composition were registered between groups. The flesh lipid content ranged from 88.0 g kg–1 (group B) to 96.8 g kg–1 (group A). Vitamin E fillet content was significantly different between groups, reaching levels of 98.0, 150.7, 225.2 and 302.0 μg g–1 lipids for group A, B, C and D, respectively. Induced TBARs values were statistically different only for group A compared with the other groups. No significant variations were registered in relation to preservation time. Because of the positive influence of vitamin E on seafood quality and the correlation between its dietary level and flesh deposition, the α-tocopherol content of the diet should be well above fish minimum requirements. 相似文献
17.
Abstract. Changes in the properties of urine and blood of carp with sekoke disease were studied. With the progress of this disease, the parameters of blood and particularly urine changed significantly. After 120 days, urine flow, osmolarity and concentrations of inorganic ions (K+ , Ca2+ , Mg2+ , Cl− ) and organic compounds (ammonium, creatine and creatinine, protein, glucose) in the experimental group showed higher values than those of the controls. Even after 60 days, when clinical signs of sekoke disease were not evident, abnormally high concentrations of ammonium, protein and glucose in the urine were found in the experimental group. 相似文献
18.
Gemma Giménez-Papiol Francesc Padrós Ana Roque Alicia Estévez & Dolores Furones 《Aquaculture Research》2009,40(4):504-508
Larvae of two Mediterranean Sparidae species, Sparus aurata and Dentex dentex , were used to test the efficacy of a peroxide-based product (Ox-Aquaculture© ) on the reduction in bacterial load in larval rearing water and its effects on larval survival. Eleven-day-old S. aurata larvae and 15-day-old D. dentex larvae were exposed to different concentrations of Ox-Aquaculture© (50, 100 and 200 mg L−1 , and 20 and 50 mg L−1 respectively) for 1 h. Results indicated that 50 and 20 mg L−1 were the most effective concentrations for the reduction in bacterial load (at least one order of magnitude) after 1 h treatment, without affecting larval survival and/or vitality in 11 dph S. aurata and 15 dph D. dentex larvae respectively. Ox-Aquaculture© concentrations of 200 and 50 mg L−1 during 1 h affected negatively final survival rate of the larvae of S. aurata and D. dentex respectively. 相似文献
19.
A Gregory L A Munro M Snow K L Urquhart A G Murray R S Raynard 《Journal of fish diseases》2009,32(6):481-489
This study investigated infection dynamics of infectious salmon anaemia virus (ISAV) by conducting two experiments to examine minimum infective dose and viral shedding of ISAV. In terms of minimum infective dose, the high variability between replicate tanks and the relatively slow spread of infection through the population at 1 × 101 TCID50 mL−1 indicated this dose is approaching the minimum infective dose for ISAV in seawater salmon populations. A novel qPCR assay incorporating an influenza virus control standard with each seawater sample was developed that enabled the quantity of ISAV shed from infected populations to be estimated in values equivalent to viral titres. Viral shedding was first detected at 7 days post-challenge (5.8 × 10−2 TCID50 mL−1 kg−1 ) and rose to levels above the minimum infective dose (4.2 × 101 TCID50 mL−1 kg−1 ) on day 11 post-challenge, 2 days before mortalities in ISAV inoculated fish started. These results clearly demonstrate that a large viral shedding event occurs before death. Viral titres peaked at 7.0 × 101 TCID50 mL−1 kg−1 15 days post-infection. These data provide important information relevant to the management of ISA. 相似文献
20.
Four diets (T0 –T3 ) were formulated reducing the fishmeal (Indian) component by 100 g kg–1 from 300 to 0 g kg–1 and including proportionately increasing quantities of maize. Diets were fed for 120 days at 50 g kg–1 body weight to triplicate groups of common carp (av. wt. 2.11–2.18 g) stocked at 1 m–2 in mud bottomed cement tanks (18 m2 ), fertilized with poultry manure. Fish growth, SGR and FCR in the different treatments were statistically not significantly different ( P > 0.05). PER was lowest for the 300 g fishmeal kg–1 diet treatment (diet T0 ), increasing with decrease in dietary fishmeal content (diets T1 –T3 ). Fish survival ranged from 96.29 to 100%. Diets influenced carcass composition and digestive enzyme activity. A significant increase in lipid deposition was recorded with increasing dietary carbohydrate content. Amylase, protease and lipase activities were higher in fish fed with diets T2 and T3 . The protein sparing effect of dietary carbohydrate and the economic implication of eliminating fishmeal from the diet are discussed. 相似文献