Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

When spermatozoa of Arbacia punctulata are labeled with 32P and treated with soluble egg jelly, radiolabel is incorporated into histone H3. The time course of labeling correlates with the period of chromatin decondensation of sperm pronuclei in eggs. Phosphorylation is on serine and may result from increased turnover of phosphate on H3. The macromolecular fraction of egg jelly (and not the peptide fraction) is the inducer of H3 phosphorylation. The reaction is dependent on external Ca2+ and is induced by monensin and A23187. H3 phosphorylation is not induced by the phosphodiesterase inhibitor IBMX and relatively high (250 microM) concentrations of the protein kinase inhibitor H8 are needed to block the reaction, suggesting that it is cAMP independent. A surprising finding is that merely diluting the cells into Na+ free media is the most effective method to induce the radiolabeling of H3. These results are in contrast to findings on the egg jelly induced phosphorylation of histone H1 in S. purpuratus spermatozoa. These species differences must reflect the great evolutionary divergence between these two sea urchin species in the mechanism of regulation of the phosphorylation of nuclear proteins during fertilization.
...
PMID:Egg jelly induces the phosphorylation of histone H3 in spermatozoa of the sea urchin Arbacia punctulata. 246 41

Capacitation of hamster caudal spermatozoa at a density of 1 x 10(6)/ml is associated with a progressive rise in cAMP levels that precedes the onset of hyperactivated motility. This increase is not expressed by caput spermatozoa incubated under identical conditions. Both the incidence of hyperactivation and the rise in cAMP levels are severely attenuated in the absence of exogenous calcium. Neither factor is restored to control levels by the addition of the phosphodiesterase inhibitor IBMX, although in the presence of exogenous calcium, this reagent increased cAMP levels, stimulated percentage motility and advanced the appearance of hyperactivation. Treatment of spermatozoa at a density of 1 x 10(6)/ml with the calmodulin antagonist, calmidazolium (CZ), caused severe disruption of sperm motility and abolished hyperactivation, while causing only a slight reduction in cAMP content. Addition of IBMX in the presence of CZ elevated cAMP content to levels higher than normally observed during capacitation but did not restore either coordinated or hyperactivated motility. To determine both the mechanisms responsible for this elevation of cAMP content and the changes that occur during epididymal maturation to facilitate the expression of this increase, the free cytosolic calcium concentration, ATP levels, and intracellular pH of caput and caudal cells were compared. The calcium content of caudal spermatozoa rose significantly at a time when cAMP levels were increasing, while ATP content and intracellular pH fell. However, the inability of caput spermatozoa to express a rise in cAMP content was not due to deficiencies in any of these factors. These results indicate a positive role for the cAMP rise in the expression of hyperactivated motility and that the fundamental control mechanism governing both these events may be the influx of calcium that accompanies capacitation in this species.
...
PMID:Relationship between calcium, cyclic AMP, ATP, and intracellular pH and the capacity of hamster spermatozoa to express hyperactivated motility. 254 81

Cyclic nucleotide phosphodiesterase in the plasma membranes of bovine epididymal spermatozoa was stimulated by added Ca2+ and calmodulin. The rate of hydrolysis and responsiveness toward calmodulin was greater for cAMP than for cGMP. The kinetic analysis of the activity revealed two forms of phosphodiesterase with apparent Km values of 7.5 and 95 microM for cAMP. Calmodulin stimulated both of the activities by increasing the Vmax without affecting the Km's. The activity response with respect to Ca2+ concentration appears to be biphasic in both the absence and presence of added calmodulin. Trifluoperazine inhibited the Ca2+- and calmodulin-sensitive enzyme activity in a dose-dependent manner. The calmodulin-stimulated phosphodiesterase activity in the sperm plasma membranes can be solubilized and absorbed to a Calmodulin-Sepharose affinity column in the presence of Ca2+.
...
PMID:Calmodulin-stimulated cyclic nucleotide phosphodiesterases in plasma membranes of bovine epididymal spermatozoa. 283 7

8-Azido cAMP photoaffinity labeling of cAMP-dependent protein kinase regulatory subunits (R1 = 49 K;R2 = 55K) was done on spermatozoa from species lacking, and species containing an epididymis. Spermatozoa from sea urchin and trout contained only R1, while rat caudaepididymal spermatozoa contained both R1 and R2 subunits. This was established by the Mr value of the 8-azido cAMP photolabeled moieties, and a biochemical analysis based on the known differences of protein-nucleotide interactions of Type I and II cAMP-dependent protein kinases. Sea urchin and trout sperm R1 subunits were similar to mammalian sperm R1 subunits in co-migration on SDS-polyacrylamide gels and in both saturation and specificity of nucleotide binding. Calcium enhanced photoprobe binding to rat R1 and R2 subunits and to sea urchin R1 subunit without revealing a sea urchin R2 subunit. Likewise, phosphodiesterase incubation of sea urchin and trout spermatozoa prior to photolabeling did not reveal R2 subunits. These data suggest that the cAMP regulation of sperm physiology may require R1 subunit in species both with and without an epididymis. Further taxonomic study is necessary to determine whether evolutionary acquisition of the epididymis and internal fertilization may have created unique environments favoring the addition of sperm R2 regulatory subunits of cAMP-dependent protein kinase.
...
PMID:A comparative analysis of cAMP-dependent protein kinase regulatory subunits in sea urchin and rat spermatozoa. 299 17

In vitro trials with washed spermatozoa incubated in medium containing 1 mg/ml of the methyl xanthine phosphodiesterase inhibitor PF showed improved counts of total motile and total progressively motile spermatozoa in cases of oligospermia/asthenospermia. Application of this agent in a PROST program for a series of nine couples presenting for treatment with histories of failed fertilization in vitro resulted in five pregnancies (four singleton, one triplet) and the subsequent delivery of normal infants. The results warrant further evaluation of this sperm treatment for cases of severe male factor infertility.
...
PMID:Preliminary results using pentoxifylline in a pronuclear stage tubal transfer (PROST) program for severe male factor infertility. 338 13

Sea urchin spermatozoa demembranated with Triton X-100 in the presence of EGTA, termed potentially asymmetric, generate asymmetric bending waves in reactivation solutions containing EGTA. After they are converted to the potentially symmetric condition by extraction with Triton and millimolar Ca++, they generate symmetric bending waves in reactivation solutions containing EGTA. In the presence of EGTA, their asymmetry can be restored by addition of brain calmodulin or the concentrated supernatant obtained from extraction with Triton and millimolar Ca++. These extracts contain calmodulin, as assayed by gel electrophoresis, radioimmunoassay, activation of brain phosphodiesterase, and Ca++-dependent binding of asymmetry-restoring activity to a trifluorophenothiazine-affinity resin. Conversion to the potentially symmetric condition can also be achieved with trifluoperazine substituted for Triton during the exposure to millimolar Ca++, which suggests that the calmodulin-binding activity of Triton is important for this conversion. These observations suggest that the conversion to the potentially symmetric condition is the result of removal of some of the axonemal calmodulin and provide additional evidence for axonemal calmodulin as a mediator of the effect of Ca++ on the asymmetry of flagellar bending.
...
PMID:Modulation of the asymmetry of sea urchin sperm flagellar bending by calmodulin. 392 94

Lizard spermatozoa, which are non-motile in the testis, develop the ability to swim as they pass along the excurrent duct. The addition of caffeine, a phosphodiesterase inhibitor, induced forward motility in spermatozoa from the caput epididymidis and increased the velocity of spermatozoa from the distal part of the epididymis. Caffeine had no effect on the motility of testicular spermatozoa. This suggests that sperm motility in this species is cyclic AMP-dependent but this factor alone is not sufficient to induce testicular sperm motility. In samples from the distal region of the epididymis, sperm motility was maximal in April just after the breeding season and then decreased significantly during the following months. A parallel can be drawn between these data and the levels of testosterone in the plasma. In the lizard, as in mammals, the epididymis may play an important role in the maturation of spermatozoa.
...
PMID:Acquisition of sperm motility and its maintenance during storage in the lizard, Lacerta vivipara. 402 Jul 69

Hamster spermatozoa were isolated from the caput, corpus and cauda epididymidis. They were observed in culture medium at 37 degrees C with a phase-contrast microscope and their motility recorded cinematographically. About 20 p. 100 of the caput epididymidis spermatozoa were motile and moved in a confined space with no forward progression. 30 p. 100 of the corpus epididymidis spermatozoa were motile, showing increased flagellar activity and moving in wide circles. 90 p. 100 of the cauda epididymidis spermatozoa were motile and moved forward. Forward motility was induced in immotile spermatozoa from the caput epididymidis by adding cyclic 3'-5' adenosine monophosphate (cAMP) phosphodiesterase inhibitors (caffeine, theophylline, IMX) and epididymal plasma. The best stimulation was initiated by 15 mM caffeine with 10 p. 100 of cauda epididymal plasma; a mean of 60 p, 100 of forward motility was obtained which lasted for one hour and then ceased. Cinematographic studies revealed that some induced sperm movements differed from the equivalent natural ones by the amplitude of the head movements. It is shown that during epididymal transit of hamster spermatozoa, the induction of forward motility requires not only an increased cAMP level but also factors from the cauda epididymal plasma. The idea that glycoprotein of epididymal origin initiates forward motility is discussed.
...
PMID:Development and initiation of sperm motility in the hamster epididymis. 618 85

The effect of cyclic nucleotide analgoues upon the immediate induction of the guinea pig acrosome reaction (AR) was studied. Dibutyryl (dB) CGMP and 8-bromo-cGMP, when added to sperm suspensions after varying periods of preincubation in glucose-free BWW medium (NaCl 94.59 mM, KCl 4.7 mM, CaCl2 1.71 mM, KH2PO4 1.19 mM, MgSO4 1.19 mM, NaHCO3 25.07 mM, pyruvate 0.25 mM, lactate 21.58 mM, and bovine seru albumen 1 g/liter), induced the AR in a large proportion of spermatozoa relative to controls. The proportion of ARs induced upon the addition of dB cGMP or 8-bromo-cGMP (10mM) at 1 h was equivalent to that obtained after a 5-h incubation in glucose-free BWW alone. The effect of cGMP analogues was concentration dependent over the tested range of 2-12 mM (less than 1-20%). The simultaneous addition if imidazole (10 mM), a cAMP phosphodiesterase stimulator, potentiated the effect (imidazole + 12 mM 8-bromo-cGMP: 73%). cAMP analogues were without effect. The presence of extracellular Ca++ was required, and it is suggested that a rise in the cGMP/CAMP ratio triggers Ca++ influx and the AR.
...
PMID:Induction of the acrosome reaction in guinea pig spermatozoa by cGMP analogues. 624 66

Calmodulin was purified to apparent homogeneity from sea urchin spermatozoa by heat-treatment at 85 degrees C, ammonium sulphate precipitation at pH 4.2, DEAE-Sephacel chromatography and gel filtration on Sephadex G-100. Approximately 8.3 micrograms calmodulin were recovered per 10(10) sperm cells. The sperm calmodulin had an apparent molecular weight of 17 800. The purified calmodulin activated calmodulin-deficient phosphodiesterase from pig coronary arteries, with half-maximal activation occurring at approximately 40 ng calmodulin/ml. Trifluoperazine also inhibited the sperm calmodulin activity. These results demonstrate that calmodulin is present in high amounts in sea urchin spermatozoa, and that it is essentially the same as the calmodulin isolated from various other tissues.
...
PMID:Purification and characterization of calmodulin from sea urchin spermatozoa. 625 34


<< Previous 1 2 3 4 5 6 7 8 9 Next >>

---