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1.
Outer dynein arm polypeptides that possess Mg+2-adenosine triphosphatase (ATPase) activity have been extracted from the flagellar axonemes of demembranated bovine sperm. Electron microscopy of intact and salt-extracted sperm demonstrates a relatively selective removal of the outer dynein arms. The salt extract contains a specific ATPase activity of 55 nmoles inorganic phosphate (Pi)/min/mg protein. Sucrose density gradient centrifugation of this extract results in a 6-fold increase in specific activity of ATPase (333 nmole/Pi/min/mg protein), which sediments as a single 13S peak. Concomitant with the increase in specific activity, there is enrichment of three high molecular weight polypeptides (Mr greater than 300,000) characteristic of dynein heavy chains. ATPase activities in the initial extract and in the 13S peak are inhibited by concentrations of vanadate and erythro-9-[3-2-(hydroxynonyl)]adenine similar to those that inhibit ATPase activity in sea urchin sperm dynein. These findings indicate that outer arm dynein ATPase can be extracted and partially purified from bovine sperm.  相似文献   

2.
erythro-9-[3-(2-Hydroxynonyl)]adenine, an inhibitor of protein carboxylmethylation and dynein-ATPase activity, inhibited fast axonal transport in vitro in frog sciatic nerves. Its site of action might be associated with an ATPase on which transport depends, since specific carboxylmethylation inhibitors lacked effects on transport. The levels of high energy phosphates and protein synthesis were unaffected by the drug at a transport-inhibiting concentration, making disturbances due to metabolic effects less likely. An erythro-9-[3-(2-hydroxynonyl)]adenine-sensitive ATPase was looked for in various nerve fractions but has so far not been resolved.  相似文献   

3.
A dynein-like ATPase activity has been isolated previously from soluble extracts of unfertilized sea urchin eggs. However, the use of non-quantitative isolation techniques, in particular affinity for microtubules or Ca2+/calmodulin, has precluded accurate estimates of dynein pool size. We have taken the unique approach of using dynein-like ATPase activity to quantitate the egg dynein pool. This approach is based on the isolation by anion-exchange chromatography on DEAE-Sephacel of a peak of dynein-like ATPase activity comprising 65% of soluble ATPase activity in the cytosolic extract. Identification of cytoplasmic dynein was based on dose-dependent inhibition by erythro-9-[3-(2-hydroxynonyl)]adenine and orthovanadate, low GTPase activity and a sedimentation coefficient of 12 S. Two high molecular weight polypeptides corresponding to the A- and D-bands of axonemal dynein were shown to copurify with dynein-like ATPase activity and to undergo specific photocrosslinking with [alpha-32P]ATP, suggesting that they were egg dynein catalytic polypeptides. The specific ATPase activity of these putative catalytic polypeptides was determined to be 1.2 mumol.min-1.mg-1. The specific dynein-like ATPase activity of the crude soluble extract of unfertilized sea urchin eggs was determined to be 0.004 mumol.min-1.mg-1. The concentration of putative dynein catalytic polypeptides was therefore determined from the ratio of the specific activities of crude to pure cytoplasmic dynein catalytic polypeptide to be 0.33% of soluble protein, or 99 pg per egg. This is approximately 3-fold greater than the mass of dynein catalytic polypeptides estimated to be present in cilia at the blastula stage of sea urchin embryonic development. The large amount of cytoplasmic dynein in unfertilized eggs suggests that it could act as a precursor of embryonic ciliary dynein. Three minor peaks of ATPase activity were also resolved from cytosolic extracts and shown to be dynein-like. However, their GTPase activities were 2-4-fold higher than that of cytoplasmic dynein, raising the possibility that egg cytoplasm may contain several isoforms of dynein.  相似文献   

4.
The unicellular green alga Pleurenterium tumidum Bréb. performs a unique type of circular nuclear migration, wherein the nucleus leaves its central position and starts revolutions in the cortical isthmus area about 10 h after mitosis. This motion lasts for at least 12 h with an average velocity of about 1 h per revolution. Possible force generation modes during circular nuclear migration of Pleurenterium were investigated by application of inhibitors and the use of digital time‐lapse video microscopy. 5′‐Adenylylimidodiphosphate, a nonhydrolyzable nucleotide analogue, retarded or inhibited circular nuclear migration, suggesting that ATPase dependent motor proteins are involved. Ado‐ ciasulfate‐2, a kinesin specific inhibitor, caused displacement of the nucleus, suggesting that the linkage between the microtubule track and the nucleus is lost. The nucleus was still able to move for short distances, but no normal revolutions took place. Erythro‐9‐[3‐(2‐hydroxynonyl)] adenine, a dynein ATPase inhibitor, led to complete inhibition of nuclear revolutions, suggesting a function in force generation also for this molecular motor. In addition, kinesin‐ and dynein‐like proteins were detected in Pleurenterium extracts by Western blotting. The myosin specific inhibitor 2,3‐butanedione 2‐monoxime did not influence circular nuclear migration in Pleurenterium. This result and the absence of actin filaments around the migrating nucleus as depicted by means of microinjection of Alexa phalloidin in the present study indicate that the actin‐myosin system can be excluded from force generation.  相似文献   

5.
Summary The giant coenocytic green algaCaulerpa is well known for its large scale amyloplast transport. The majority of chloroplasts, however, is immobilized in the cortex of the cell. By applying UV-irradiation to localized areas of the cortex chloroplasts can be induced to slowly move towards and aggregate around the irradiated spot. Chloroplast movement is blocked by cytochalasin D, but not by colchicine or the microtubule herbicide cremart. The dynein inhibitor erythro-9-[3-(2-hydroxynonyl)] adenine (EHNA) also has no effect on chloroplast movement. However, both microtubule- and dynein-specific inhibitors block movement of amyloplasts. Using the previously developed technique of microdissection followed by immunofluorescence microscopy it can be shown that, concomitant with changes in motile behavior of chloroplasts upon irradiation, actin filaments form and rearrange around the irradiation spot. It is concluded that in contrast to amyloplast movement, immobilization and movement of chloroplasts are dependent on actin but not on microtubules. Therefore, two individual motile mechanisms appear to have evolved for independent positioning and motility of the two populations of plastids in the giant coenocyteCaulerpa.Abbreviations EHNA erythro-9-[3-(2-hydroxynonyl)] adenine - DMSO dimethylsulfoxide - MT microtubule - NEM N-ethylmaleimide  相似文献   

6.
Cilia from the protozoan Tetrahymena pyriformis were demembranated and then extracted for 5 min with a buffer containing 0.5 M NaCl. The briefly extracted axonemal pellet was then reextracted for about 20 hr. The soluble material obtained from each extraction was resolved into 14S and 30S dynein ATPases by sedimentation on sucrose density gradients and tested for sensitivity to added calmodulin. The 14S dynein obtained by a 5-min extraction was generally insensitive to added calmodulin, whereas that obtained by 20-hr extraction of the 5-min extracted axonemes was activated by calmodulin, the activation being much larger in the “light” 14S fractions than in the “heavy” fractions. The 30S dynein ATPase obtained by a 5-min extraction was generally activated over 1.6-fold by added calmodulin, whereas that obtained by the subsequent long extraction was usually activated only 1.3-fold. After further purification of the 5-min extracted 30S dynein and of the 5-min to 20-hr-extracted 14S dynein on DEAE-Sephacel, these dyneins retained much of their calmodulin activatability. The ATPase activity of both 14S and 30S dyneins was inhibited more strongly by erythro-9-[3-(2-hydroxynonyl)] adenine and by vanadate in the presence of added calmodulin than in its absence. These data suggest that the only ATPase activity present in the fractions studied is that of the dyneins and demonstrate that both the 14S and 30S dynein ATPases may be obtained in forms mat are activated by added calmodulin as well as in forms that are insensitive to added calmodulin.  相似文献   

7.
Summary A novel microtubule binding protein was isolated from cell extracts of pig brain after selective destruction of high Mr MAPs by Ca2+-activation of endogenous proteases. The protein had an apparent Mr of 300,000, but several criteria, including peptide maps, immunological crossreactivities, resistance to Ca2+-activated proteolysis, and inability to induce microtubule assembly, distinguished this protein from the major high Mr microtubule associated proteins MAP-1 and MAP-2. Certain molecular properties of the protein resembled those of dynein: its size under denaturing conditions, its crossreactivity with antibodies toTetrahymena dynein, the ATP-dependence of its microtubule binding, the erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA)—sensitivity of its ATPase activity and its resistance to Ca2+-activated proteolysis. However, in peptide maps and the insensitivity of its ATPase activity to vanadate the protein could be differentiated fromTetrahymena dynein heavy chain polypeptides. Based on the properties characterized so far, the protein seems qualified to function as a mechanochemical enzyme in the cytoplasm of mammalian brain cells and could represent a cytoplasmic dynein variant.Abbreviations EGTA ethylene glycol bis([3-aminoethylether)N,N,N',N'-tetraacetic acid - MAP microtubule associated protein - Mr molecular weight - SDS sodium dodecyl sulfate  相似文献   

8.
R D Green 《Life sciences》1980,26(5):399-406
The cyclic AMP content of dense cultures of C1300 murine neuroblastoma cells (clone N2a) was elevated after incubation for short periods of time in minimal volumes of serum-free medium (SFM) containing Ro 20 1724, a potent nonxanthine phosphodiesterase inhibitor. This elevation was prevented by theophylline, an adenosine antagonist, and was retarded by dipyridamole or benzylthioinosine, inhibitors of nucleoside transport. Cyclic AMP was also elevated by erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), a potent adenosine deaminase inhibitor. This effect of EHNA was more pronounced in dense cultures, in small volumes of bathing medium, and was antagonized by dipyridamole. The addition of adenosine deaminase to growth medium or SFM lowered the cyclic AMP levels attained after the addition of Ro 20 1724. We conclude that N2a cells continually release adenosine into the growth or bathing medium via the nucleoside transport system and that sufficient concentrations may be achieved to tonically stimulate adenylate cyclase and influence processes controlled by the cyclic AMP:cyclic AMP-dependent protein kinase system.  相似文献   

9.
Thylakoids isolated from the cyanobacterium Anabaenacylindrica exhibit Photosystem II activity. Photosynthetic electron transfer from water to ferricyanide and to 2,6-dichlorophenolindophenol is inhibited by 3-(3,4-dichlorophenyl)-N-N′-dimethyl urea. Diphenylcarbazide stimulates ferricyanide and 2,6-dichlorphenolindophenol photoreduction, whilst inhibiting oxygen evolution. Diphenylcarbazide-supported Photosystem II activity is completely insensitive to 3-(3,4-dichlorophenyl)-N-N′-dimethyl urea, indicating that the site of action of this inhibitor lies on the donor side of Photosystem II in A.cylindrica, before the site of electron donation by diphenylcarbazide.  相似文献   

10.
Vanadate selectively inhibited dynein ATPase, 10?7M causing 50% inhibition under favorable conditions. Actomyosin ATPase was inhibited only by up to a thousand times higher concentration. In both cases vanadate inhibition was not competitive with ATP. Reversal by catecholamines was correlated with reduction of vanadate. The motility of demembranated sea urchin or mammalian sperm was arrested by vanadate concentrations similar to those which inhibited dynein ATPase; a thousand times higher concentration was needed to paralyze live sperm. The possible utility of vanadate sensitivity as a probe for dynein involvement in non-axonemal motile systems was explored with respect to brain ATPase associated with tubulin obtained by cycles of assembly, and ATPases associated with mitotic apparatus isolated from sea urchin embryos.  相似文献   

11.
Effects of various inhibitors on motility, heat, and lactate production of ejaculated bovine sperm were determined in the presence of antimycin A and rotenone. erythro-9-[3-(2-Hydroxynonyl)]adenine (EHNA) and polyvinylpyrrolidone (PVP-360) stopped motility and reduced heat or lactate production by 30-50%. Carbodiimides resulted in loss of motility and a reduction of metabolism by 60-75%. Quercetin treatment, which enhanced rather than inhibited motility, depressed heat and lactate production by 50-60%. Since mechanical immobilization reduced heat production by only 30%, the question arises as to what other cellular processes are major contributors to the energy budget. Inhibitors of ion flux had little-to-no effect on heat or lactate production, suggesting that neither mitochondrial nor Na+/K+ ATPases were major ATP-requiring processes. Calcium flux at the plasma membrane also was minimal and previous reports eliminated glycolytic substrate cycling as major consuming processes for ATP. Although quercetin inhibited lactate production in intact cells, no effect of quercetin on cell-free glycolysis and the ATPase activities of isolated dynein was detected. Quercetin did, however, inhibit ATPase activity of plasma membrane, suggesting that this unidentified ATPase may contribute to the formation of ADP and Pi required for lactate production by the intact cell. We propose (a) that the bioenergetic costs of motility are divided between regulatory events and dynein-microtubule interaction (dynein ATPase), (b) that some of the membrane-related processes may be "inefficient," and (c) that quercetin may render these steps more "efficient," in a manner analogous to its action on the Na+/K+ pump of Ehrlich ascites tumor cells.  相似文献   

12.
An improved purification method for cytoplasmic dynein   总被引:5,自引:0,他引:5  
An improved method has been devised for the purification of cytoplasmic dynein from sea urchin eggs (Strongylocentrotus droebachiensis and S purpuratus). This protocol introduces three changes over a previously published procedure (Hisanaga and Sakai: J Biochem 93:87, 1983)--the substitution of diethylaminoethyl (DEAE)-cellulose for hydroxylapatite chromatography, the elimination of sucrose density gradient centrifugation, and the use of phosphocellulose chromatography. These changes reduce the time and increase the efficiency of the purification procedure. The purified egg cytoplasmic dynein has enzymatic properties in common with axonemal dynein, including ionic specificity (Ca++ATPase/Mg++ ATPase = 0.8) and inhibition by sodium vanadate and erythro-9-2,3-hydroxynonyl adenine (EHNA). As assayed by silver staining of polyacrylamide gels, the cytoplasmic dynein is composed of two high molecular weight polypeptides (greater than 300 kilodaltons) that comigrate with flagellar dynein heavy chains, and lesser amounts of three lower molecular weight bands. None of these polypeptides appears to contain bound carbohydrate. The purification procedure can be modified slightly to allow the preparation of cytoplasmic dynein in only 2 days from as little as 3-5 ml of packed eggs, a 20-fold reduction over the previous method. This more rapid and efficient method will facilitate the investigation of cytoplasmic dynein in other systems where starting material is limited, including tissue culture cells and nerve axoplasm.  相似文献   

13.
Cholinergic synaptic vesicles isolated from the electric organ of Torpedo californica are confirmed to exhibit energy-linked uptake of [3H] acetylcholine. [3H]Acetylcholine is concentrated in the vesicles by a factor of 10–14 in the presence of MgATP and bicarbonate. This active uptake can be completely inhibited by the mitochondrial uncouplers 3-t-butyl-5-Cl-2′-Cl-4′-nitro-salicylanilide (S-13) and p-nitrophenol. The vesicle-associated ATPase is stimulated by S-13 in the same concentration range which inhibits [3H]acetylcholine active uptake. The ATPase also is stimulated by valinomycin. Both S-13 and valinomycin effects are independent of exogenous Ca2+. Thus, a proton gradient generated by the vesicle-associated ATPase appears to be coupled to active [3H]acetylcholine uptake.  相似文献   

14.
Repeated Biogel P6 chromatography of the urine from a patient with fucosidosis yielded several fractions containing fucosyloligosaccharides and glycopeptides. Two of these were shown by 1H nuclear magnetic resonance (1H-n.m.r.) spectroscopy and permethylation analysis to have the following structures respectively: (I) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman (1→36) βman (1→4) glcNAc and (II) αfuc (1→3) [βgal (1→4)] βglcNAc (1→2) αman (1→36) βman (1→4) βglcNAc (1→4) [αfuc (1→36)] βglcNAc-Asn.  相似文献   

15.
Dynein-mediated autophagosome (AP) trafficking was recently demonstrated to contribute to the formation of autophagolysosomes (APLs) and autophagic flux process in coronary arterial myocytes (CAMs). However, it remains unknown how the function of dynein as a motor protein for AP trafficking is regulated under physiological and pathological conditions. The present study tested whether the dynein-mediated autophagy maturation is regulated by a redox signalling associated with lysosomal Ca2+ release machinery. In primary cultures of CAMs, reactive oxygen species (ROS) including H2O2 and O2−. (generated by xanthine/xanthine oxidase) significantly increased dynein ATPase activity and AP movement, which were accompanied by increased lysosomal fusion with AP and APL formation. Inhibition of dynein activity by (erythro-9-(2-hydroxy-3-nonyl)adenine) (EHNA) or disruption of the dynein complex by dynamitin (DCTN2) overexpression blocked ROS-induced dynein activation, AP movement and APL formation, and resulted in an accumulation of AP along with a failed breakdown of AP. Antagonism of nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ signalling with NED-19 and PPADS abolished ROS-enhanced lysosomal Ca2+ release and dynein activation in CAMs. In parallel, all these changes were also enhanced by overexpression of NADPH oxidase-1 (Nox1) gene in CAMs. Incubation with high glucose led to a marked O2−. production compared with normoglycaemic CAMs, while Nox1 inhibitor ML117 abrogated this effect. Moreover, ML117 and NED-19 and PPADS significantly suppressed dynein activity and APL formation caused by high glucose. Taken together, these data suggest that ROS function as important players to regulate dynein-dependent AP trafficking leading to efficient autophagic maturation in CAMs.  相似文献   

16.
Sensitivity of CaMg ATPase from axonic plasma membrane (APM) and sarcoplasmic reticulum (SR) of lobster, Homarus, americanus, to DDT was studied. The CaMg ATPase found in SR with the high Ca2+ affinity is sensitive to DDT while the portion of ATPase related to the low Ca2+ affinity site is not inhibited by DDT. Also, DDT is more inhibitory against the CaMg ATPase prepared from APM than the one obtained from SR. The relationship between inhibition of the CaMg ATPase by DDT in the axonic nerve membrane and in, vivo poisoning symptoms of the nervous system is discussed.  相似文献   

17.
Sun-Shine Yuan 《Steroids》1982,39(3):279-289
A-ring enollactones 1a, 1b or 9 derived from 4-cholesten-3-one, testosterone benzoate or 3-oxo-4-estren-17β-yl benzoate were condensed with [1,2-13C2]acetyl chloride to give intermediates 2a, 2b or 10. 2a and 2b were cyclized by acid or base to give 3,4-13C2-labeled 4-cholesten-3-one and testosterone, respectively. [3,4-13C2]4-Cholesten-3-one was converted via reduction of its trimethylsilyl enol ether to [3,4-13C2]cholesterol. Acetyl enollactone 10 was cyclized in acetic acid to [3,4-13C2]3-oxo-4-estren-17β-yl benzoate followed by aromatization and hydrolysis to produce [3,4-13C2]estradiol-17β. Alternatively, cyclization of 10 with base afforded [3,4-13C2]3-oxo-4-estren-17β-ol directly, which was then oxidized and aromatized to yield [3,4-13C2]estrone. Ozonolysis of progesterone, conversion to the diketal ester 16 and acylation followed by acid hydrolysis furnished [3,4-13C2]progesterone.  相似文献   

18.
The 2′,3′-dialdehyde of ADP, obtained by periodate oxidation of ADP, inhibited the hydrolytic activity of the purified Ca2+, Mg2+-activated ATPase of Escherichiacoli. In the initial stages of the reaction inhibition was due to the reaction of 1 mol inhibitor/active site. When non-specific labelling of amino groups by the dialdehyde was lowered by the simultaneous presence of 15 mM ATP in the reaction mixture, 3 mol “ATP-protectable” binding sites/mol ATPase were found. “ATP-protectable” binding of the dialdehyde was not observed when the hydrolytically inactive ATPase of an unc A mutant of E.coli was used although binding of the inhibitor to non-protected amino groups still occurred. This suggests that the mutant ATPase is unable to bind ATP or that the amino groups with which the dialdehyde reacts in the native enzyme are absent or masked.  相似文献   

19.
Motile detergent-extracted cells of Tetrahymena and Chlamydomonas   总被引:6,自引:6,他引:0       下载免费PDF全文
Tetrahymena and Chlamydomonas cells treated with high (0.25-0.5%) concentrations of the detergent Nonidet P-40 in appropriate buffers retain the shape of the intact cells but are devoid of any ciliary activity unless supplied with MgATP. ATP causes them to swim actively, with beat parameters and swimming patterns indistinguishable from those of intact cells. Both types of detergent-extracted cells are completely devoid of ciliary membranes. The Tetrahymena preparations also lack all cellular membranes, whereas cellular membranes remain intact in the Chlamydomonas preparations. Experiments demonstrating the effects of ATP, ADP, vanadate, erythro-9-[3-2-(hydroxynonyl)]-adenine, and Ca++ are described to illustrate the use of these detergent-extracted cells in research on ciliary motility.  相似文献   

20.
Cauliflower mitochondria do not have a 2,4-dinitrophenol-stimulated ATPase unless they are permitted a brief period of respiration (respiratory priming) or are preincubated for an extensive period with ATP (self-priming). Both priming processes are dependent on Mg2+, and are collapsed by 2,4-dinitrophenol in the absence of ATP. Corn mitochondria, which have an endogenous DNP-ATPase, contain significantly more Mg2+ and adenine nucleotides than cauliflower mitochondria. Primed cauliflower mitochondria have Mg2+ content comparable to corn mitochondria. Cauliflower mitochondria will actively accumulate adenine nucleotides through atractyloside-insensitive sites. It appears that priming consists of creating an electrochemical potential which is needed for accumulation of Mg2+ or adenine nucleotides or for charge compensation of the ATP4?ADP3-? exchange.  相似文献   

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