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PubMed1963

NONSPORULATING, RESPIRATION-DEFICIENT VARIANTS OF SACCHAROMYCES PASTORIANUS INDUCED BY CYCLOHEXIMIDE.

Lomander, L. (Gothenburg University, Gothenburg, Sweden), and K. Gundersen. Nonsporulating, respiration-deficient variants of Saccharomyces pastorianus induced by cycloheximide. J. Bacteriol. 86:956-965. 1963.-When grown on cycloheximide-containing solid medium, Saccharomyces pastorianus gave rise to rough colonies, consisting of two morphologically and physiologically different kinds of organisms, named primary colony organisms and secondary colony organisms. The primary colony organisms were slow-growing and cycloheximide-resistant as compared with the secondary ones which, like the parent organisms, were fast-growing in the absence of cycloheximide, but were inhibited when cycloheximide was incorporated in the medium. Cell aggregates, large swollen cells, and dwarf cells were found among the secondary colony organisms. The primary colony organisms were smaller than normal cells but were larger than the dwarf cells. The primary colony organisms also proved to have lost the faculty to sporulate, whereas the secondary colony organisms sporulated like the untreated parents. In contrast to the normal organisms and the secondary colony organisms, the primary colony organisms did not consume oxygen in manometric experiments with glucose as a substrate. On solid medium without cycloheximide, the latter organisms grew considerably better in a nitrogen atmosphere than in air.

Anti-Bacterial Agents↗

PubMed1969

Simian virus 40 deoxyribonucleic acid replication. I. Effect of cycloheximide on the replication of SV40 deoxyribonucleic acid in monkey kidney cells and in heterokaryons of SV40-transformed and susceptible cells.

Infectious deoxyribonucleic acid (DNA) was extracted from green monkey kidney (CV-1) cultures at various times after the cultures were infected with simian virus 40 (SV40) at input multiplicities of 0.01 and 0.1 plaque-forming unit (PFU) per cell. A pronounced decrease in infectious DNA was observed from 3 to 16 hr after virus infection, suggesting that structurally altered intracellular forms may have been generated early in infection. Evidence is also presented that SV40 DNA synthesis requires concurrent protein synthesis. DNA replication was studied in the presence and absence of cycloheximide in: (i) SV40-infected and uninfected cultures of CV-1 cells; (ii) cultures synchronized with 1-beta-d-arabinofuranosylcytosine (ara-C) for 24 to 30 hr prior to the addition of cycloheximide; and (iii) in heterokaryons of SV40-transformed hamster and susceptible monkey kidney cells. DNA synthesis was determined by pulse-labeling the cultures with (3)H-thymidine at various times from 24 to 46 hr after infection. In addition, the total infectious SV40 DNA was measured. Addition of cycloheximide, even after early proteins had been induced, grossly inhibited both SV40 and cellular DNA syntheses. The activities of thymidine kinase, DNA polymerase, deoxycytidylate deaminase, and thymidylate kinase were measured; these enzyme activities remained high for at least 9 hr in the presence of cycloheximide. SV40 DNA prelabeled with (3)H-thymidine before the addition of cycloheximide was also relatively stable during the time required for cycloheximide to inhibit further DNA replication.

Animals↗

PubMed1971

Analysis of the molecular forms of simian virus 40 deoxyribonucleic acid synthesized in cycloheximide-treated cell cultures.

Cycloheximide addition at various times from 24 to 36 hr after virus infection markedly inhibits the rate of simian virus 40 (SV40) deoxyribonucleic acid (DNA) synthesis in monkey kidney (CV-1) cultures. To determine whether superhelical (form I) SV40 DNA was synthesized in the cycloheximide-inhibited cultures, extracts were prepared by the method of Hirt from cultures labeled with (3)H-thymidine ((3)H-dT) and were analyzed by cesium chloride-ethidium bromide (CsCl-EtBr) equilibrium centrifugation and by velocity sedimentation in neutral sucrose gradients. When control or cycloheximide-treated cultures were labeled for 2 or 4 hr with (3)H-dT at 36 or 37 hr after infection, 71 to 83% of the radioactivity soluble in 1 m NaCl was detected in closed-circular SV40 DNA (form I). Cycloheximide treatment did not generate an increase of higher multiple circular forms of SV40 DNA. In pulse-chase experiments with or without cycloheximide treatment, radioactivity first appeared in nicked molecular forms sedimenting faster than open-circular SV40 DNA (form II), and then was chased into superhelical form I SV40 DNA. These results suggest that in cycloheximide-treated SV40-infected cultures: (i) polynucleotide ligase concentrations are adequate, and (ii) duplication errors causing formation of circular oligomers of SV40 DNA are not enhanced.

Amino Acids↗

PubMed1971

Effect of cycloheximide on intestinal secretion induced by hypertonic glucose.

Since intestinal fluid production in experimental cholera can be limited by cycloheximide, an inhibitor of protein synthesis, the same agent was used to determine whether there are similar mechanisms for fluid production in response to an osmotic gradient. Intestinal fluid production was measured by perfusion of paired rabbit jejunal loops (10 cm) in vivo, in controls, and in animals receiving 20 mg/kg intravenous cycloheximide one hour before perfusion. In each animal one loop was perfused with isotonic Ringer's lactate and the other with a hypertonic glucose-Ringer's lactate solution, 563 mOsm/litre. In control animals mean fluid production in the hypertonic loop was seven times that in the isotonic loop. Cycloheximide decreased the fluid response to the hypertonic stimulus by one half (p < 0.001). In a separate measurement of bidirectional sodium fluxes, using sodium(22), it was shown that the decreased net sodium movement into the lumen observed after cycloheximide was the result of decreased flux from blood to lumen. The major histological alteration after cycloheximide was on the crypt epithelial cells with sparing of villus crests. Glucose absorption was unaffected. These data parallel the observed effect of cycloheximide on cholera exotoxin induced secretion, suggesting that a process requiring continued protein synthesis is also necessary for the intestinal fluid response to an osmotic gradient.

Animals↗

PubMed1975

DNA replication in SV40-infected cells. XI. The properties of SV40 DNA and nucleoprotein complex synthesized in the presence of cycloheximide.

Cycloheximide inhibits simian virus 40 (SV40) DNA synthesis in productively infected African green monkey kidney cells. The residual viral DNA synthesized in the presence of this drug is deficient in superhelical turns as measured by band sedimentation in the presence of several concentrations of ethidium bromide. The superhelical density of SV40 DNA synthesized in the presence of cycloheximide is about one half that of viral DNA produced in the absence of this drug. Ribonuclease H and alkali treatment were employed to determine if ribonucleotides could be detected in closed circular SV40 DNA synthesized in the presence of cycloheximide. While both these approaches detected ribonucleotides in mitochondrial DNA, no identification of ribonucleotides in SV40 DNA synthesized in the presence of cycloheximide was found. The SV40 nucleoprotein complex synthesized in the presence of cycloheximide has a slower sedimentation rate (35S) and a higher bouyant density (1.54 g/cm3) than the complex made in the absence of this drug (50S; 1.47 g/cm3). The protein:DNA ratio of the SV40 nucleoprotein complex is normally about 0.9. This ratio is reduced to about 0.6 when the complex is synthesized in the presence of cycloheximide.

Cell Line↗

PubMed1982

Regulation of ureagenesis in neonatal rat liver: influence of cycloheximide in vivo and in vitro.

In order to establish whether the postnatal rise in five urea cycle enzyme activities is associated with protein synthesis, the effects of cycloheximide on urea cycle enzyme activities, citrulline and urea productions in vivo and in vitro were studied. A single injection of cycloheximide (10 microgram) 9 h after birth significantly prevented the rise in enzyme activities and citrulline concentration which normally occurred after birth, while the urea level remained unchanged. These data suggest that the postnatal rise in urea cycle enzyme activities might be associated with a protein synthesis. The rate of citrulline synthesis by liver slices was reduced (about 50%) in cycloheximide-treated neonatal liver, while the rate of urea production was not significantly decreased. The results obtained in vivo are in good agreement with in vitro experiments: citrullinogenesis was only affected by cycloheximide treatment. When cycloheximide 10 mM was added to the incubation medium, the ability of control neonatal liver slices to produce citrulline and urea was reduced to 42 and 11%, respectively. Since argininosuccinic acid addition in the medium did not produce a rise in urea synthesis, it is concluded that argininosuccinase is most responsive after incubation in cycloheximide and therefore becomes the rate-limiting step of the urea synthesis.

Animals↗

PubMed1988

Non-specific elongation of cell cycle phases by cycloheximide in rat 3Y1 cells, and specific reduction of G1 phase elongation by simian virus 40 large T antigen.

Partial inhibition of protein synthesis by cycloheximide caused prolongation of G1, S and G2 phases in rat 3Y1 fibroblasts. In cells expressing simian virus 40 (SV40) large T antigen, by infection with SV40 in the previous generation, the prolongation of G1 phase in the presence of cycloheximide was suppressed. However, the prolongation of S and G2 phases in the presence of cycloheximide was not suppressed in cells expressing large T antigen, by infection with SV40 in the current generation. Similarly, when density-arrested cells (cells in G0 phase) were infected with SV40 (either wild-type strain or a mutant deleted in the unique coding region for small t antigen) and reseeded sparsely in the presence of cycloheximide, the cycloheximide-induced delay of entry into S phase was suppressed. In this case, the reduction in [35S]methionine incorporation, that in protein accumulation and that in cell volume increase, were not surmounted by SV40 infection. In T-antigen-negative cells, all the regions in G1 phase seemed to be sensitive to cycloheximide, i.e. they suffered elongation. These results suggest that, in comparison with cells that enter S phase by the action of growth factors, cells expressing large T antigen can enter S phase more efficiently through a quite different process.

Animals↗

PubMed1994

Suppression of plasminogen activator production in sheep embryos in vitro after treatment with cycloheximide or ouabain.

Effects of the metabolic inhibitors cycloheximide and ouabain on development in vitro and plasminogen activator production by sheep embryos were investigated. Embryos (n = 152) from the eight-cell to the morula stage were surgically collected from naturally mated, oestrus-synchronized and superovulated Polypay ewes. In Expt 1, embryos (n = 104) were grouped by cell stage, cultured in Whitten's medium with 1.5% BSA containing 0, 0.1 or 1.0 microgram cycloheximide ml-1 for 24 h, washed and cultured in this medium for 168 h. In Expt 2, morulae (n = 48) were cultured for 48 h in Whitten's medium with 1.5% BSA transferred to the same medium containing 0 or 1.0 mmol ouabain l-1 and cultured for 24 h, and then washed and cultured in this medium for 120 h. At 24 h intervals in both experiments, the medium was recovered and analysed for plasminogen activator. In Expt 1, eight-cell embryos underwent limited development; little difference in the production of plasminogen activator due to cycloheximide treatment was therefore observed. Compared with medium without cycloheximide, treatment with 1.0 microgram cycloheximide ml-1 reduced the number of 16-cell embryos (P < 0.05) and morulae (P < 0.05) (60% versus 10% and 77% versus 8%, respectively) that began to hatch. The mean production of plasminogen activator was greatest in embryos cultured initially as morulae compared with that of 16-cell and eight-cell embryos (P < 0.05). Cycloheximide treatment suppressed the mean production of plasminogen activator in a dose-dependent manner (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1976

Modification of the hepatotoxicity of D-galactosamine in the rat by cycloheximide.

The effect of cycloheximide (1.5 mg/kg), a potent inhibitor of protein biosynthesis, on D-galastosamine (375 mg/kg)-induced hepatic necrosis and hepatic triglyceride accumulation was studied in rats. Serum transaminase levels, 24 hr after D-galactosamine administration, were significantly reduced in animals treated simultaneously or 4 hr before D-galactosamine with cycloheximide, when compared to animals given D-galactosamine alone. Transaminase levels in rats given cycloheximide 4 hr after D-galactosamine were not reduced. Histological grading of hepatocyte necrosis showed a similar pattern of protection in the pretreated and simultaneously treated groups. Hepatic triglycerides were significantly reduced only in the latter group. Fatality 48 hr after D-galactosamine administration was significantly less common in rats pretreated with cycloheximide when compared to rats given D-galactosamine without cycloheximide, and surviving animals in the cycloheximide pretreated group had a lower serum transaminase level, a lower necrosis score, and a reduced hepatic triglyceride level. These data are consistent with the concept that protein synthesis is important in the pathogenesis of D-galactosamine-induced hepatotoxicity.

Alanine Transaminase↗

PubMed2002

The influence of cycloheximide on Na,K-ATPase activity in cultured human lens epithelial cells.

PURPOSE: Earlier studies from this laboratory demonstrated the ability of lens epithelium to synthesize new Na,K-adenosine triphosphatase (Na,K-ATPase) catalytic subunit (alpha) polypeptide under conditions of increased ion permeability. In the present study, the authors considered whether continuous synthesis of Na,K-ATPase protein is necessary for maintenance of Na,K-ATPase activity in lens cells. METHODS: Na,K-ATPase activity was measured by quantifying the ouabain-sensitive rate of ATP hydrolysis in cultured human lens epithelial cells (HLE-B3) permeabilized with digitonin. The abundance of Na,K-ATPase alpha subunit was determined by Western blot analysis. Synthesis of Na,K-ATPase alpha1 polypeptide was investigated by measuring 35S-methionine incorporation. RESULTS: Na,K-ATPase activity was reduced to less than 20% of the control level in HLE-B3 cells exposed to 100 microM cycloheximide for 24 hours. However, as judged by Western blot density, the abundance of Na,K-ATPase alpha1 and alpha3 subunit in cycloheximide-treated cells was 90% and 84% of the control level, respectively. 35S-methionine incorporation experiments revealed detectable labeling of Na,K-ATPase alpha1 subunit polypeptide within 30 minutes, consistent with alpha1 polypeptide synthesis. Na,K-ATPase alpha1 polypeptide labeling was also detected in the epithelium of intact rat lenses that had been allowed to incorporate 35S-methionine. Cycloheximide abolished 35S-methionine incorporation into Na,K-ATPase alpha1 subunit polypeptide of HLE-B3 cells. When added during the chase phase of the experiment, cycloheximide was found to slow the disappearance of labeled alpha1 polypeptide, consistent with a reduced rate of polypeptide degradation. CONCLUSIONS: The results suggest that a continuous cycle of Na,K-ATPase alpha1 synthesis and degradation may occur in lens epithelial cells. Cycloheximide appeared to inhibit Na,K-ATPase protein synthesis and degradation. The observed reduction of Na,K-ATPase activity after treatment with cycloheximide indicates that even though Na,K-ATPase remains abundant, Na,K-ATPase becomes inactivated when protein synthesis is inhibited.

Animals↗

PubMed1990

Proton magnetic resonance study of cycloheximide-ribosome interactions.

Cycloheximide-ribosome interactions from sensitive and resistant organisms were studied by proton magnetic resonance spectroscopic techniques. The two methyl resonances of cycloheximide upon interaction with ribosomes from Saccharomyces cerevisiae showed preferential broadening. Comparison of cycloheximide line broadening as effected by ribosomes from S. cerevisiae (sensitive) and Microsporum canis (resistant) revealed that less cycloheximide is bound to the M. canis ribosomes. From the decrease in line broadening observed with increasing temperature it may be concluded that cycloheximide-ribosome interaction is a fast exchange reaction. Tetracycline did not compete with cycloheximide for binding site(s) on the ribosomes of S. cerevisiae.

Binding Sites↗

PubMed1986

The effects of cycloheximide upon transcription of rRNA, 5 S RNA, and tRNA genes.

The effects of inhibitors of protein synthesis upon transcription have been re-examined. Cycloheximide (1 microgram/ml) inhibits incorporation of uridine into RNA of P1798.S20 lymphosarcoma cells. Filter hybridization studies indicate that labeling of pre-rRNA is inhibited 60-80% after 1 h and quantitative S1 nuclease mapping reveals a corresponding decrease in the amount of cellular pre-rRNA. Cycloheximide also inhibits labeling of 5 S RNA and tRNA, but incorporation of uridine into poly(A+) RNA is unaffected. Transcription experiments carried out in nuclei from cycloheximide-treated cells indicate that the inhibitor causes a selective decrease in the activity of RNA polymerases I and III. Cell-free extracts from P1798.S20 were used to transcribe the cloned mouse rRNA gene, Syrian hamster 5 S RNA gene, and the Drosophila tRNAArg gene. Extracts from cycloheximide-treated cells were inhibited in this respect. Transcription of rRNA and 5 S RNA genes was inhibited by 90% after 2 h and 50% inhibition occurred within 20-30 min. Transcription of the tRNA gene was inhibited 75% after 2 h with a half-time of approximately 1 h. Inhibition was due neither to a direct effect of cycloheximide nor to the presence of nucleases or diffusible inhibitors of transcription. Moreover, transcription of rDNA in extracts from cycloheximide-treated cells could be restored by the addition of a partially purified initiation factor preparation. The data indicate that inhibition of protein synthesis results in rapid depletion of transcription factors that are required for initiation by RNA polymerases I and III. Among these is the glucocorticoid-regulated rDNA initiation factor designated TFIC.

Animals↗

PubMed1989

Acute effects of cycloheximide on the translocation of glucose transporters in rat adipose cells.

Insulin's rapid action to increase glucose transport is believed to occur primarily through the translocation of glucose transporters from an intracellular pool to the plasma membrane. To better understand the mechanism involved, we studied the role of protein synthesis in glucose transporter translocation by using the protein synthesis inhibitor, cycloheximide. Isolated rat epididymal adipose cells were incubated in the presence or absence of cycloheximide (10 micrograms/ml) for a total of 120 min. Insulin (7 nM) was added to half of the cells from both groups for the final 30 min. Protein synthesis was inhibited by approximately 90%, as measured by [14C]leucine incorporation, in the cells exposed to cycloheximide. The 3-O-methylglucose uptake in intact cells was slightly increased in the basal state with cycloheximide treatment, but the insulin-stimulated 3-O-methylglucose uptake was unchanged by cycloheximide. The distribution of glucose transporters in the different subcellular membrane fractions, as measured by the cytochalasin B binding assay, was unchanged by cycloheximide. These results suggest that insulin's stimulation of glucose transport and translocation of glucose transporters can occur without acute protein synthesis.

3-O-Methylglucose↗

PubMed1981

Cycloheximide potentiation of prostaglandin E1- and cholera toxin-stimulated cyclic AMP accumulation in NG108-CC15 neuroblastoma-glioma hybrid cells.

Previous studies have demonstrated that catecholamine responsiveness in a variety of cells can be altered by inhibitors of RNA and protein synthesis. The neuroblastoma-glioma hybrid, NG108-CC15, which lacks catecholamine-stimulated accumulation of cyclic AMP, was investigated to determine if the responsiveness to prostaglandin E1 (PGE1) could be modified by inhibitors of protein synthesis. Cycloheximide in a time-dependent manner potentiated the ability of prostaglandin E1 to stimulate accumulation of intracellular cyclic AMP. However, the alpha-adrenergic inhibition of the prostaglandin response was not affected by cycloheximide. Withdrawal of norepinephrine following a long-term incubation resulted in a potentiation of subsequent PGE1-stimulated cyclic AMP accumulation. Cycloheximide enhanced this norepinephrine withdrawal effect. Our previous studies have shown that cholera toxin induces refractoriness to beta-adrenergic agonists in C6-2B rat astrocytoma cells and that cycloheximide blocked this action of cholera toxin. In an analogous manner cholera toxin caused refractoriness to subsequent prostaglandin-stimulated cyclic AMP production in NG108-CC15 cells, and cycloheximide reduced cholera toxin-induced prostaglandin refractoriness. Thus cycloheximide potentiates the prostaglandin stimulatory effect, has no effect on the ability of alpha-agonists to inhibit the prostaglandin response, increases the stimulatory effect of PGE1 after norepinephrine withdrawal, and reduces cholera toxin-induced PGE1 refractoriness. these observations suggest that PGE1-stimulated cyclic AMP accumulation in NG108-CC15 cells contains components which are regulated by de novo protein synthesis.

Animals↗

PubMed1983

Adrenergic and antiadrenergic activity of cycloheximide in cultured rat heart cells.

Cycloheximide at concentrations between 10(-5) to 10(-3) M increased the rate of beating of rocker-cultured neonatal rat myocardial cells through activation of alpha 1-adrenoceptors. At concentrations between 3 X 10(-10) and 10(-6) M, at which [14C]-leucine incorporation into the cultured cells was not or not greatly affected, the antibiotic inhibited surmountably the positive chronotropic action of the rather nonselective beta-adrenergic agonist isoprenaline. It also antagonized the cyclic AMP response to isoprenaline. A powerful positive chronotropic action of the beta 2-selective agonist clenbuterol was not opposed by cycloheximide. Neither did cycloheximide (10(-8) and 10(-6) M) influence the acceleration of beating by phenylephrine, dibutyryl cyclic AMP, and elevation of the extracellular calcium concentration. Displacement of the nonselective beta-adrenoceptor ligand [125I]iodopindolol from its specific binding sites on the cultured heart cells by cycloheximide was diphasic, with 15 to 35 per cent of the displacement taking place below 10(-8) M cycloheximide (IC50 = = 2 X 10(-9) M) and the remaining 65 to 85 per cent above 10(-5) M. The action of low concentrations of cycloheximide on beta-adrenoceptors remains to be delineated.

Animals↗

PubMed1980

The effect of intravenously injected Ehrlich ascites tumour cells in cycloheximide-treated mice.

An intravenous injection of 5 X 10(6) washed, viable Ehrlich ascites tumour cells given to mice 2 hr before, immediately before, or 2 hr after a dose of 60 microgram/g body weight of cycloheximide, results in such animals being either dead or moribund 48 hr later. No fatalities occur when a similar number of tumour cells are given 2 hr before or 2 hr after a dose of 30 microgram/g body weight of cycloheximide. Similarly, 5 X 10(6) tumour cells are well tolerated when given to mice 18 hr after 60 microgram/g cycloheximide. It is suggested that an undefined minimum level of recipient protein synthesis is required for maintenance of life in the presence of a challenge by 5 X 10(6) tumour cells. A minimum period (less than 6 hr) is needed for an irreversible illness to result from interaction of tumour cells with a recipient animal under the maximal influence of the 60 microgram/g dose of cycloheximide. The irreversible illness is not avoided by the use of tumour cells pretreated for 2 hr with 30 microgram/g of cycloheximide, nor is the outcome altered when both recipient and tumour cells are together subjected to a 60 microgram/g dose of cycloheximide.

Animals↗

PubMed1977

Stimulatory action of cycloheximide on glucose metabolism in the rat epididymal fat pad.

The action of cycloheximide on some parameters of glucose and lipid metabolism was studied in vitro in epidiymal fat pads from fasted rats. Incubation of fat pads with cycloheximide (1 mug/ml) for 2 hours resulted in a two-fold increase in glucose uptake, glucose oxidation, incorporation of glucose into lipids, and reesterification of free fatty acid. The increase in glucose oxidation was evident in experiments in which [U-14C], [1-14C], or [6-14C]glucose was added to the media, but it was absent when the media were supplemented with pyruvate. Incorporation of glucose into glycogen and accumulation of lactate in the medium were not seriously modified by the presence of cycloheximide. The stimulatory effect of cycloheximide on incorporation of glucose into lipids was absent when insulin or cortisol was added to the medium. A cycloheximide-mediated increase in glucose uptake seems to be responsible for the subsequent changes in glucose metabolism, and would seem to be independent of an inhibition in protein synthesis; puromycin and actinomycin D did not mimic the cycloheximide action on glucose incorporation into lipids.

Adipose Tissue↗

PubMed1996

Interphase-like chromatin configuration induced by cycloheximide in maturing pig oocytes: effects of protein phosphatase inhibitors.

Embryo cloning methods could greatly benefit from the manipulation of cell cycle in oocytes from large domestic mammals. The present study was undertaken to examine the effects of the protein synthesis inhibitor cycloheximide and the inhibitors of protein phosphatases 1 and 2A okadaic acid and calyculin A on maturing pig oocytes. Cycloheximide treatment (10 micrograms/ml) induced an interphase-like chromatin configuration (ICC) in maturing oocytes. Up to 69% of the oocytes exhibited ICC when treated with cycloheximide after 24 h of in vitro culture. ICC starts to appear after a 4 h exposure to cycloheximide and the ICC percentage reached its plateau after 12 h of cycloheximide treatment. ICC is fully reversible. The addition of okadaic acid (0.5 microM) inhibited the ICC in cycloheximide-treated maturing oocytes and allowed the completion of maturation in 55% of them. In oocytes with ICC, the immunocytochemistry for tubulin revealed the rearrangement of microtubule into an interphase meshwork and these oocytes lost their ability to induce tubulin assembly, as shown after short-time taxol treatment. The addition of okadaic acid prevented this microtubule rearrangement and preserved a certain level of tubulin assembly. Calyculin appeared to be more effective than okadaic acid in the prevention of ICC. It is concluded that de novo protein synthesis is necessary during a certain period of meiotic maturation for the maintenance of metaphase chromatin configuration in pig oocytes. This protein (or proteins) acts through the inhibition of endogenous protein phosphatases, probably protein phosphatase of 2A type.

Animals↗