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1.
Jean-Claude Bonnafous Jacques Dornand Jean-Claude Mani 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,587(2):180-191
Adenosine-cyclic AMP relationships have been studied in pig mesenteric lymph node lymphocytes. The early 2–3-fold increase in cyclic AMP accumulation elicited by adenosine and 2-chloroadenosine, an adenosine deaminase-resistant analogue, could not be correlated to similar effects on the adenylate cyclase activity of disrupted cell preparations, but rather to the competitive inhibition of the low Km (0.17 μM) cyclic AMP phosphodiesterase. The existence of adenosine receptors coupled to lymphocyte adenylate cyclase, which had been proposed by several authors, could not be confirmed by this study. Adenosine-cyclic AMP relationships do not appear to be involved in concanavalin A stimulation of pig lymphocytes. 相似文献
2.
J. C. Tu 《Protoplasma》1979,99(1-2):139-146
Summary Diurnal changes in the concentration of cAMP in white clover were investigated biochemically and histochemically. Biochemical assays showed that a) the concentration of cAMP in healthy leaves was consistently higher than in CYMV-diseased leaves under the same light condition and b) the concentration of cAMP in clover leaves exhibited a diurnal cycle. The diurnal changes in cAMP concentration were present in both healthy and CYMV-diseased clover leaves. Histochemical localization tests indicated that the adenylate cyclase activity could be semi quantilated as more dense reaction products were present in the membrane systems of healthy than CYMV-diseased leaves. The histochemical results were consistent with the biochemical data. 相似文献
3.
The photosynthetic behaviour ofDunaliella viridis has been studied under a combination of three variables: irradiance (0–900 mol m–2 s–1), temperature (15, 23, 31, 38, 42 °C) and nitrogen concentration (0.05, 0.5, 1.5, 5, 10 mM NO
3
-
) at a salinity of 2 M NaCl.The highest rates of photosynthesis have been found at 31 °C and a nitrate concentration of 10 mM. There exists a synergistic effect between temperature and nitrogen availability on the photosynthesis ofD. viridis; under nitrogen deficiency oxygen evolution is low, even null at high temperature. The interaction between these two variables of control occurs in a multiplicative way. There is also a general increase in photosynthetic pigments following the increase in nitrogen concentration in the culture medium. The normalization of net photosynthesis data in relation to chlorophylla shows that nitrogen concentration makes an indirect control of the photosynthetic rate ofD. viridis through the variation of pigment concentration. 相似文献
4.
S. Sakuanrungsirikul C. H. Hocart J. D. I. Harper C. W. Parker P. C. L. John 《Protoplasma》1996,192(3-4):159-167
Summary Three independent isolates ofChlamydomonas, selected for caffeine resistance, were found to arrest in G1 phase, as determined by quantitative fluorescence measurements of DNA, when grown at a non-permissive temperature. This cell cycle arrest correlated with lowered levels of cAMP and of adenylate cyclase activity. The arrested cells could be rescued by added cAMP but not AMP, hence the defect was not one of general purine metabolism. Back-crosses to wild type revealed that the phenotypes observed result from a combination of three separable mutations. It is clear that the mutations define functions that are more stringently required for cell division than for growth since the mutant strains are able to grow up to fifteen times normal size while blocked at the non-permissive temperature. The possible interaction of cAMP dependent events with division is discussed.Abbreviations AMP
adenosine 5-monophosphate
- ATP
adenosine 5-triphosphate
- BSA
bovine serum albumin
- cAMP
adenosine 3,5-cyclicmonophosphate
- db-cAMP
dibutyryl-cAMP
- DNA
deoxyribonucleic acid
- DTT
dithiothreitol
- -cAMP
1,N6-etheno-cAMP
- EDTA
ethylenediaminetetraacetic acid
- EGTA
ethylene glycol-bis(-aminoethylether)-N,N,N,N-tetraacetic acid
- HPLC
high performance liquid chromatography
- LSA
low sulphur-high salt-acetate medium
- LYP LSA
media containing yeast extract and proteose peptone
- M1, 2, 3
mutants 1, 2, 3
- PDE
phosphodiesterase
- TAP
trisacetate-phosphate medium
- TLC
thin layer chromatography
- TYP TAP
medium containing yeast extract and proteose peptone 相似文献
5.
Cyclic AMP (cAMP) has been shown to be a primary signal of the agglutination-induced mating events of flagellar tip activation, cell wall loss, and mating structure activation in the unicellular alga Chlamydomonas reinhardtii (Pasquale and Goodenough, Cell Biol. 105 (1987), 2279–2293). The flagellar membrane adenylate cyclase of Chlamydomonas is here shown to be inhibited in vitro by EGTA, La3+, and trifluoperazine, and to be stimulated in the presence of calcium by incubation with exogenous calmodulin. Also, the motility of detergent-extracted models of Chlamydomonas is shown to be enhanced by cAMP. These observations suggest the hypothesis that the twitching motility characteristic of agglutinating Chlamydomonas gametes may be signaled by cAMP produced locally within the flagella by a calmodulin-sensitive adenylate cyclase. 相似文献
6.
Dissociation by cooling of hormone and cholera toxin activation of adenylate cyclase in intact cells 总被引:1,自引:0,他引:1
J. Van Sande R. Pochet J.E. Dumont 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,585(2):282-292
Cholera toxin, through adenylate cyclase activation reproduced cyclic AMP-mediated effects of thyroid-stimulating hormone (TSH) in dog thyroid slices, i.e protein iodination, [1-14C]glucose-oxidation and hormone secretion. Iodide and carbamylcholine decreased the cyclic AMP accumulation induced by cholera toxin as well as by TSH, which supports the hypothesis of an action of these agents beyond the steps of hormone-receptor and receptor-adenylate cyclase interaction. Cooling to 20°C did not impair the TSH induced cyclic AMP accumulation in thyroid slices, but completely suppressed the cholera toxin effect.This observation has been extended to other hormones and target tissues, such as the parathyroid hormone (PTH) (kidney cortex), adrenocorticotropic hormone (ACTH) (adrenal cortex)_and luteinizing hormone (LH) (ovary systems). As in thyroid, cooling dissociated the cholera toxin and hormonal effects on cyclic AMP accumulation. In homogenate, cooling decreased cyclic AMP generation in the presence of cholera toxin but at 20°C and 16°C a cholera toxin stimulation was still observed. These results bear strongly against the hypothesis that the glycoprotein hormones TSH and LH activate adenylate cyclase by a mechanism identical to cholera toxin. 相似文献
7.
Summary Adenylate cyclase has been localized cytochemically in female and male parents as well as during the pollen-stigma interaction with an original technique employing strontium as the capture ion and adenyl imidodiphosphate as the specific substrate. The specificity of the reaction was checked by using several controls. No final specific reaction product was detected in unpollinated P. deltoides stigmas or in the P. deltoides or P. alba pollen grains used for compatible and incompatible pollinations. In the compatible cross between P. deltoides × P. deltoides, fine dense precipitates were observed in the dictyosomes and the plasma membrane and exterior to the exine of hydrated pollen grains adhering to the stigma surface. Labeling of the stigmatic pellicle was also observed after pollen adhesion and hydration. This was accompanied by a strong reactivity of the cell wall and plasmalemma of the stigma papillae at the sites of pollen tube germination on the stigma surface and at the sites of penetration of pollen tubes between adjacent papillae. In the incompatible cross between P. deltoides x P. alba, adenylate cyclase activity was still present but reduced at the stigma surface following adhesion, hydration, and germination of P. alba pollen. This activity was completely abolished after the penetration of pollen tubes between stigma papillae. These findings suggest that in Populus, adenylate cyclase activity is correlated to pollen adhesion, hydration, and germination at the stigma surface, and that the abolition of this enzyme activity could be one of the cellular events governing the gametophytic phenotype of incompatibility in the cross between P. deltoides and P. alba. 相似文献
8.
A number of regulatory peptides were investigated for their ability to elevate plasma cAMP. Pituitary adenylate cyclase activating peptide (PACAP)-27, PACAP-38, helodermin, helospectin I and II, vasoactive intestinal peptide (VIP), glucagon, parathyroid hormone (PTH), calcitonin and calcitonin gene-related peptide were among the peptides that were highly effective in raising plasma cAMP when given intravenously in equimolar doses to conscious mice. PACAP-27 and -38 were more effective than any of the other peptides. PACAP 16–38, secretin, gastrin-17, galanin, somatostatin, cholecystokinin-8s, pancreatic polypeptide, substance P, peptide YY and neuropeptide Y were inactive and also did not interfere with the PACAP-27-evoked rise in plasma cAMP levels. Repeated injections of PACAP-27 every 30 min caused a progressive reduction in the plasma cAMP response (measured 5 min after each injection). Forskolin, an activator of adenylate cyclase, dose-dependently raised the plasma concentration of cAMP and displayed a synergistic effect when given in a low dose concurrently with PTH or PACAP-38. The phosphodiesterase inhibitor rolipram dose-dependently raised the plasma concentration of cAMP. Combined treatment with PACAP-27 and a threshold dose of rolipram resulted in an exaggerated plasma cAMP response. Kidney hilus ligation suppressed the responses to PACAP-38, PTH, helodermin, helospectin, VIP, glucagon and calcitonin. Hepatectomy suppressed the response to glucagon but was without effect on the response to the other peptides. Pancreatectomy and spleenectomy reduced the response to VIP, but was without effect on the response to the other peptides. PACAP-27 stimulated cAMP efflux from the isolated rat tail vein. Hence, it cannot be excluded that blood vessels contribute to the peptide evoked plasma cAMP response in vivo. 相似文献
9.
Distribution of Protein I, a Synapse-Specific Phosphoprotein, and Adenylate Cyclase in the Rat Spinal Cord 总被引:1,自引:1,他引:0
The longitudinal and transverse distributions of the synapse-specific phosphoprotein Protein I and adenylate cyclase in the rat spinal cord were studied. Protein I was found to be enriched in all cervical and midlumbar (L3-L5) segments, and sparse in midthoracic and sacral segments. Adenylate cyclase activity was high in all cervical and lumbosacral segments, and low in mid-thoracic segments. Cross sectionally, both Protein I and adenylate cyclase were more enriched in the dorsal half than in the ventral half in the various segments studied. The similar topographical distributions of Protein I and adenylate cyclase in the spinal cord support the idea that adenylate cyclase may be intimately associated with Protein I in the nervous system, and could thereby regulate the state of in vivo phosphorylation of Protein I through formation of cyclic AMP. 相似文献
10.
Summary Because the secretion of endolymph has been localized in the ampullar part of the frog semicircular canal, we attempted to determine by cytochemical methods the ultrastructural localization of two enzymes that are assumed to play a role in endolymph secretion: carbonic anhydrase and adenylate cyclase. Functionally, the epithelium of the frog semicircular canal can be schematically divided into three areas: sensory (crista ampullaris), secretory (dark cells), and non-sensory and nonsecretory (transitional and undifferentiated cells) areas. Carbonic anhydrase activity was widely distributed in dark cells. Dark cell labeling disappeared in the presence of acetazolamide. The other cells of the canal did not show any carbonic anhydrase labeling except for the supporting cells of the sensory cells. Adenylate cyclase activity was found on the basolateral and apical membranes of dark cells, and on the apical membrane of sensory cells; weak labeling was also observed in the other epithelial cells. In the apical membrane of the dark cells, adenylate cyclase labeling was dependent on the presence of vasotocin, the frog antidiuretic hormone. The dark cells of the frog semicircular canal thus possess the enzyme equipment needed for the secretion of endolymph and its possible hormonal regulation. 相似文献
11.
When Leptophaeria michotii was grown in conditions that permitted a stable periodicity of sporulation (asparagine 6.6 mM in darkness or asparagine 2.6 mM in continuous white light), the level of intracellular cyclic AMP was lower and the activity of the cyclic AMP phosphodiesterase higher in contrast to the cultures with an instable periodicity.With asparagine 6.6 mM and in darkness, theophylline (1 mM) increased the intracellular cyclic AMP level whereas caffeine (1 mM) had no effect. Theophylline (0.01 and 0.1 mM) or caffeine (0.01–1 mM) provoked a rhythm instability under these conditions. Isoproterenol (1 mM) increased the cyclic AMP level. Nevertheless, the instable rhythm observed in control fed with asparagine 2.6 mM in darkness, was partially stabilized with isoproterenol 0.01 M or 0.01–1 mM. Exogenous cyclic AMP (0.01–1 mM) provoked a complete regulation of the rhythm with asparagine 2.6 mM and a shortening of the stable period (from 27 to 21 h) when the fungus was grown on asparagine 6.6 mM.These results underlined the fact that Leptosphaeria rhythm regulation was not dependent on the cyclic AMP level only. 相似文献
12.
Effect of Cadmium on Cellular Viability in Two Species of Microalgae (Scenedesmus sp. and Dunaliella viridis) 总被引:1,自引:0,他引:1
Letty Beatriz C. Marcano Ingrid M. Carruyo Xiomara M. Montiel Carolina B. Morales Patricia Moreno de Soto 《Biological trace element research》2009,130(1):86-93
We determined the effect of several concentrations of cadmium (0, 5, 10, and 20 μg/l) on cellular viability in the microalgae
Scenedesmus sp. and Dunaliella viridis, by measuring growth at 0, 24, 48, 72, and 96 h and pigment production at 10 days. Algae were obtained from the Nonvascular
Plant Laboratory collection, in the Facultad Experimental de Ciencias, Universidad del Zulia, Venezuela. Growth was measured
by cellular counting, while pigment content was evaluated using conventional spectrophotometric techniques. Growth of both
species decreased in the exposed cultures comparing with the control, but its behavior was similar, because in both control
and exposed cultures, its was observed an adaptive phase in the first hours, as well as a growth phase after 72 h. Cadmium
concentrations above 10 μg/l produced an adverse effect on pigment production, depending on the concentration and/or exhibition
time. However, even though cadmium inhibited growth and pigment production, levels of both parameters indicated cellular viability,
demonstrating the adaptability of the algae cultures when they were exposed to the metal. 相似文献
13.
Prof. Rita Pascolini P. Ceccarelli A. M. Gargiulo S. Lorvik 《Cell and tissue research》1985,239(2):443-445
Summary In the testis of Esox lucius at the time of spermiation, activity of cyclic adenosine 3,5-monophosphate (cAMP) was immunocytochemically localized at the level of the Sertoli cells. In these cells adenylate cyclase activity was also ultracytochemically demonstrated by using adenylyl imidodiphosphate as a substrate. Reaction products of adenylate cyclase were primarily detectable on the basal and adluminal plasma membranes and on the surface of protrusions of the cell body into the lumen. 相似文献
14.
Isolation and characterization of a sodium-dependent phosphate transporter gene in Dunaliella viridis 总被引:3,自引:0,他引:3
Li Q Gao X Sun Y Zhang Q Song R Xu Z 《Biochemical and biophysical research communications》2006,340(1):95-104
A sodium-dependent phosphate transporter gene, DvSPT1, was isolated from a cDNA library using a probe derived from a subtracted cDNA library of Dunaliella viridis. Sequencing analyses revealed a cDNA sequence of 2649 bp long and encoded an open-reading frame consisting of 672 amino acids. The deduced amino acid sequence of DvSPT1 exhibited 31.2% identity to that of TcPHO from Tetraselmis chui. Hydrophobicity and secondary structure prediction revealed 11 conserved transmembrane domains similar to those found in PHO89 from Saccharomyces cerevisiae and PHO4 from Neurospora crassa. Northern blot analysis indicated that the DvSPT1 expression was induced upon NaCl hyperosmotic stress or phosphate depletion. Functional characterization in yeast Na+ export pump mutant G19 suggested that DvSPT1 encoded a Na+ transporter protein. The gene sequence of GDvSPT1 (7922 bp) was isolated from a genomic library of D. viridis. Southern blot analysis indicated that there exist at least two homologous genes in D. viridis. 相似文献
15.
Stacy Psychoyos Jane Dove Ben Strowbridge Irving Nusynowitz 《Journal of neurochemistry》1982,38(5):1437-1445
An improved procedure utilizing a simple fractionation technique is described for the preparation and use of [2-3H]adenine-prelabeled vesicles from guinea pig cerebral cortex containing highly responsive adenylate cyclase activity. Adenosine consistently increased activity 1500--2000%, contrasted with activations of 200--300% previously reported by other investigators. Adenosine at 5 microM was more active in our system than at 20 times this concentration in studies by other investigators, increasing activity by 580--840%. Experimental conditions were explored, and Ca2+ was found to be necessary during tissue homogenization, but not during subsequent vesicle incubation. However, neither the higher Ca2+ concentration used by us (2.5 mM) nor the method of tissue homogenization could adequately explain the high activity of our preparations. The size of the incubation vessel was critical for both low basal activity and high activity in the presence of adenosine. Our preparations were similar to others in that combinations of neurohormones, which included histamine and epinephrine, elicited higher activities than individual neurohormones. Inspection of our vesicle preparations by scanning electron microscopy also showed them to be compatible with previously described preparations. 相似文献
16.
The cyclic AMP receptor protein (CRP) regulates the expression of many genes in Escherichia coli. The protein is a homodimer, and each monomer is folded into two distinct structural domains. In this study, we have used differential scanning calorimetry (DSC) and circular dichroism (CD) to measure the enthalpy change and melting temperature of the apo-CRP and CRP complexes with cAMP or DNA sequences lac, gal, and palindromic ICAP. DSC and CD measurements showed irreversible thermal denaturation process of CRP. Enthalpy of dissociation of the protein–DNA complex, as measured by DSC, depends on the DNA sequence. The thermal transition of the protein in CRP-DNA complexes, measured by CD, indicates that the protein stability in the complex is also DNA sequence-dependent. 相似文献
17.
The bovine heart calmodulin-dependent phosphodiesterase can be phosphorylated by cAMP-dependent protein kinase, resulting in a decrease in the enzyme's affinity for calmodulin. The phosphorylation of calmodulin-dependent phosphodiesterase is blocked by Ca2+ and calmodulin and reversed by the calmodulin-dependent phosphatase. The dephosphorylation is accompanied by an increase in the affinity of the phosphodiesterase for calmodulin. The CaM-dependent phosphodiesterase isozymes of heart and brain are regulated by calmodulin, but the affinity for calmodulin are different. Furthermore, the bovine heart CaM-dependent phosphodiesterase isozyme in stimulated at much lower Ca2+ concentration than the bovine brain isozymes. Results from this study suggest that the activity of this phosphodiesterase is precisely regulated by cross-talk between Ca2+ and cAMP signalling pathways. 相似文献
18.
In order to isolate a cDNA clone of ribosome inactivating protein (RIP), a cDNA library was constructed in Uni-ZAP XL vector with poly(A) RNA purified from leaves of Amaranthus viridis. To get the probe for screening the library, PCR of phage DNA was conducted using the vector primer and degenerate primer designed from a conserved putative active site of the RIPs. Twenty-six cDNA clones from about 600,000 plaques were isolated, and one of these clones was fully sequenced. It was 1,047 bp and contained an open reading frame encoding 270 amino acids. The deduced amino acid sequence had a putative signal sequence of 17 amino acids and a putative active site (AIQMVAEAARFFKYIE) conserved in other RIPs. E. coli cells expressing A. viridis RIP cDNA did not grow well as compared to control cells, indicating that recombinant A. viridis RIP presumably inactivated E. coli ribosomes. In addition, recombinant A. viridis RIP cDNA produced by E. coli had translation inhibition activity in vitro. 相似文献
19.
A wasp venom, mastoparan, rapidly increased the cytosolic free Ca2+ concentration ([Ca2+]i) and activated phosphorylase in rat hepatocytes in a concentration-dependent manner. Mastoparan could increase [Ca2+]i even in the absence of extracellular Ca2+, but a larger increase was observed in the presence of extracellular Ca2+. Thus, mastoparan mobilized Ca2+ from intracellular and extracellular Ca2+ stores. It also activated inositol triphosphate (IP3) accumulation, but did not stimulate cAMP production. From these results, we conclude that mastoparan activates rat hepatic glycogenolysis mediated by the accumulation of IP3, which causes an increase of [Ca2+]i but not that mediated by cAMP. 相似文献