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PubMed1981

A modified isolation technique for Chlamydia psittaci in L-cells treated with cycloheximide and glucocorticoid.

Various auxiliary treatments of L-cells employed for the isolation and cultivation of C. psittaci were investigated in order to develop an improved method for the detection of the agent, in addition to the aid obtained by centrifugation and cycloheximide treatment. Glucocorticoid treatment increased the observed number of inclusions considerably through a preservative effect on host cells and enhanced an spontaneous re-infection. Besides, the hormone made the scanning of cell culture for inclusions more convenient through an altered cell morphology. This method was tested with two extreme species types that differed as regards cytopathogenicity and growth rate. The length of the cultivation period was of great importance for the diagnostic result. Especially the cytopathogenic agent-type influenced the optimal time of cell culture fixation, which was situated around 48 or 88 hours post infection (h p.i.). Owing to the cytotoxicity of field samples (milk secretion), the cell culture technique (48 h p.i.) was less sensitive compared to the conventional isolation method in embryonated eggs. However, a different sampling technique improved the result, and simultaneous use of the secondary multiplication cycle of chlamydia (88 h p.i.) makes the less cumbersome cell culture technic recommendable.

Animals↗
PubMed1982

Cell cycle control in synchronously dividing antheridial filaments of Chara vulgaris L. as revealed by cycloheximide pulse treatment.

In antheridial filaments of Chara vulgaris L. (cell cycle S+G2+M type) cycloheximide (2.5 micrograms/ml) totally inhibits protein synthesis after 2 h. The protein synthesis is resumed after the removal of the inhibitor from the medium. The inhibition of protein synthesis in the second half of G2 phase causes supercontraction of mitotic chromosomes, whereas in the late G2 phase it induces diminishing of tubulin content and the inhibition of the initiation of DNA synthesis in the next generation of antheridial filaments. The inhibition of protein synthesis in G2 phase does not affect the mitotic index. The inhibition of protein synthesis during S phase results in a lower rate of DNA replication and the prolongation of S phase. The inhibition of protein synthesis in the second half of G2 phase of the previous generation and in the S phase of the given generation causes mitotic delay which increases in proportion to the duration of G2 phase in the given generation.

Cycloheximide↗
PubMedDate not supplied

[Inhibition by cycloheximide of the incorporation of radioactive amino acids into nuclear matrix proteins of Zajdela ascites hepatoma].

Proteins of nuclear matrix readily incorporated labelled amino acids after incubation of ascites Zajdela hepatoma cells with 14C-hydrolyzate of chlorella proteins. Cycloheximide at the concentrations, inhibiting the cytoplasmic protein synthesizing system, significantly decreased the labelled amino acid incorporation both into nuclear proteins and into proteins of nuclear matrix but the antibiotic effect was less distinct in the matrix. The incorporation into proteins with molecular mass below 26 KD and above 150 KD was especially distinctly inhibited as shown in experiments on separation of the matrix proteins by means of SDS-polyacrylamide gel electrophoresis. Besides the inhibition of the incorporation of amino acids, a decrease in content was found in studies of the fraction of matrix low molecular proteins. The high rate of metabolism of nuclear matrix low molecular proteins is discussed.

Amino Acids↗
PubMed1982

[Effect of iron, actinomycin D and cycloheximide on the GTP-cyclohydrolase synthesis in flavinogenic yeasts].

The effect of Fe on the GTP-cyclohydrolase activity of the yeasts Pichia guilliermondii ATCC 9058 and Torulopsis candida BKM 13 whose flavinogenesis is controlled by Fe was investigated. The GTP-cyclohydrolase activity of yeast cells grown in an iron-deficient medium was 40-50 times that of the cells grown in an iron-rich medium. In the latter case the incubation of cells with alpha, alpha'-dipyridyl or 8-oxyquinoline also increased the enzyme activity. Cycloheximide prevented the rise in the cyclohydrolase activity in both cases, thus suggesting the participation of Fe in the control of the enzyme synthesis. Actinomycin D inhibited the enzyme derepression induced by alpha, alpha1-dipyridyl or 8-oxyquinoline in the P. guilliermondii MS1-37 mutant possessing a high sensitivity to this antibiotic. It is assumed that Fe is involved in the control of GTP-cyclohydrolase synthesis in flavinogenic yeasts at the transcription level.

Aminohydrolases↗
PubMed1981

Cycloheximide treatment modifies the pattern of "metastasis" following intravenous injection of Ehrlich ascites tumour cells.

Cyclohexamide treatment of recipient mice at various times in relation to an intravenous injection of Ehrlich ascites tumor cells alters the pattern of consequent "metastatic" disease as compared with the pattern in untreated, tumour-injected animals. Analysis of the results suggests the existence of a cycloheximide-sensitive host mechanism for eliminating arrested tumour cells. This mechanism could play an important role in determining the ultimate localisation pattern of neoplastic disease following an intravenous injection of Ehrlich tumour cells.

Animals↗
PubMedDate not supplied

[Effect of cycloheximide on glucan biosynthesis in the growth process of Saccharomyces carlsbergensis yeasts].

Biosynthesis of alkali-acid-insoluble beta-glucan was studied in the course of growth of the yeast Saccharomyces carlsbergensis IBPM Y366. Synthesis of this important component of the cell wall was shown to depend on the stage of the cultural growth. The rate of 14C-glucose incorporation into the glucan fraction was maximal at the beginning and in the middle of the logarithmic growth phase. Cycloheximide, an inhibitor of protein synthesis, at a concentration of 10 micrograms/ml inhibited glucan synthesis at the beginning and by the end of the logarithmic growth phase, but stimulated synthesis of this polymer in the middle of the logarithmic phase of growth of this organism.

Cell Wall↗
PubMed1980

[Actidione-cycloheximide and the route of intestinal absorption of lipids in the rat].

The effect of actidione-cycloheximide on the intestinal absorption of 14C oleic acid was studied on male rats using the ex vivo perfusion technique in control rats and those treated with a protein synthesis inhibitor. With the amounts of lipid infused, the radioactivity recovered in portal blood lipids was the same in treated rats and in controls. However, differences were observed in the appearance of oleic acid in the portal blood during the first 15 min. When protein synthesis was inhibited, absorption occurred earlier via the portal blood. The absorption balance in this type of experiment was considerably lower than normal absorption probably because or surgical stress. In conclusion, when esterification was impaired, oleic acid seemed to be absorbed via the portal blood at the beginning of the experiment like short or medium-chain fatty acids.

Animals↗
PubMed1980

Action of short-term cycloheximide administration associated with colchicine on nuclear and chromosome structure in cleaving Newt eggs. Reappearance of chromomeres?

Association of short-term cycloheximide (CHM) administration (1/3, 1/2 or 1 cycle) with long-term treatment by colchicine (Co) confirms the results obtained by CHM alone under similar conditions, namely the striking relationship between the starting-time of treatment and the type of nuclei obtained (centred telophasic or non-centred prophasic). This relationship is highly significant. Various nuclear structures were observed: they correspond to a special evolution of the abnormal nuclei during telophase, telo-prophase and prophase which is very different from that in untreated ones. A difference in evolution of the central and peripheral parts of the same nucleus explains their centred structure. On the contrary, this difference disappears at prophase. The association CHM-Co favours the unveiling of beads which are interpreted as prophasic chromomeres. These beads are of different size, spacing and form according to the moment of the prophasic evolution attained. Electron microscopy study confirms the strong dispersion of chromatin by CHM and the beaded appearance of chromosomes by CHM and Co. Simultaneously, many dense bodies are accumulated in the centrospheres, as after quinoline and glutaraldehyde administration. The mechanisms of production of centred nuclei and of the beaded appearance of chromosomes are discussed.

Animals↗
PubMed1994

Permissive effect of cyclic AMP and cycloheximide for induction by sodium butyrate of the glycoprotein hormone alpha-subunit gene in choriocarcinoma cells.

Expression of the chorionic gonadotropin alpha-subunit (alpha CG) gene is regulated differently in human tumor cell lines derived from trophoblastic and nontrophoblastic tissues. This is based, at least in part, on the observations that production of alpha CG is increased by cAMP but not by sodium butyrate in choriocarcinoma cells (JEG-3), whereas production of alpha CG is increased by butyrate but not by cAMP in cervical carcinoma cells (HeLa). Data presented herein confirm that the steady-state levels of alpha CG mRNA are increased approximately 10-fold by cAMP in JEG-3 cells, but additionally demonstrate that these levels can be further increased (to 25-fold) by sodium butyrate in conjunction with the cyclic nucleotide. Similar effects were achieved with the phorbol ester 12-0-tetradecanoylphorbol-13-acetate, which also acted synergistically with cAMP to increase alpha CG mRNA levels (24-fold). Butyrate and 12-0-tetradecanoylphorbol-13-acetate had little or no effect when added alone (1.5-fold and 2.5-fold, respectively) or in combination with one another (3.8-fold). Induction of the alpha CG gene by cAMP was independent of protein synthesis, as mRNA levels were comparable when JEG-3 cells were treated with cAMP in the absence and presence of cycloheximide (CHX). Unexpectedly, alpha CG mRNA levels were also elevated 8- to 10-fold in response to a combination of butyrate and CHX, but CHX alone or in combination with 12-0-tetradecanoylphorbol-13-acetate had no effect. Gel mobility shift assays demonstrated changes in the pattern of proteins binding to a cAMP response element and to a trophoblast-specific element with nuclear extracts from cells treated with CHX but not with cAMP or sodium butyrate. Together, these results suggest that induction patterns of the alpha CG gene by butyrate and cAMP in trophoblast- and nontrophoblast-derived tumor cell lines are less distinct than suggested previously and indicate that CHX, which is permissive for induction by butyrate, causes a significant shift in electrophoretic mobility of trans-acting factors involved in alpha CG gene expression.

Base Sequence↗
PubMed1995

Localization of a cycloheximide-sensitivity response element in the human thymidine kinase gene promoter.

In order to localize the segment of the human thymidine kinase (TK) gene promoter that mediates sensitivity of TK mRNA expression to the presence of cycloheximide (CX), a series of promoter truncation mutants was prepared between the 460-base pair (bp) promoter that was demonstrated previously to be sensitive to CX and the 83-bp promoter that was demonstrated previously to be insensitive to CX. TK promoters containing 370, 300, 160, or 130 bp of 5'-flanking sequence were all sensitive to inhibition by CX. Further truncation to 100 bp of 5'-flanking sequence eliminated CX sensitivity. Electrophoretic mobility shift assays using a probe containing most of this region (but omitting the SP1 binding site at the 5'-end of the 130-bp promoter) identified some complexes whose formation was sensitive to the presence of CX. Comparison of the sequences of oligonucleotides that were able to compete for formation of mobility shift complexes identified the sequence GCGGCC as a putative CX-sensitivity response element. Two such sequences are found between 83 and 130 bp 5' of the TK capsite. Mutation of the distal sequence attenuated sensitivity of TK mRNA expression to CX, while mutation of the proximal sequence had minimal effect on CX sensitivity. Thus, these data have localized a CX-sensitivity response element to a segment of TK promoter about 120 bp 5' of the capsite that includes the hexamer GCGGCC.

Base Sequence↗
PubMed1978

Lower gastric secretion and higher incorporation of orotic acid into liver RNA in rats treated with 5-azacytidine and cycloheximide.

Out of different azapyrimidines tested for their ability to affect metabolism of orotic acid in the liver of rats kept on food only 5-azacytidine resulted in the enhanced incorporation of orotate into liver RNA following 24 hr pretreatment. Similar effect was observed also in cycloheximide-treated animals. No stimulation of orotic acid utilization following 5-azacytidine or cycloheximidine treatment was observed in the liver of starved animals. Both drugs (but not other pyrimidine analogues tested) depressed markedly gastric secretion in rats and caused decreased evacuation of the stomach. The decreased secretion of pepsin and lower gastric acidity resulting in drug-simulated starvation of the treated animals are discussed in relation to the enhanced uptake of orotic acid into liver RNA.

Animals↗
PubMed1975

[Rubella virus. II. Replication in Vero calls and effects of actinomycin Dand cycloheximide].

Budding at the plasmic membrane is the primary mode of production of rubella virus in Vero cells. Intense cytopathic effect is observed even if only 10% of the cells are infected. Actinomycin D has little effect on the multiplication of rubella virus but cycloheximide inhibits its growth. This inhibitiion is probably due to the reduction of cellular protein synthesis and not to a direct action of the inhibitorson the virus multiplication. Viral proteins in infected cells have not been demonstrated. The presence of a viral substance inhibiting normal cellular synthesis is discussed.

Animals↗
PubMedDate not supplied

Protein synthesis inhibition is not a requisite for puromycin- and cycloheximide-induced c-myc mRNA superinduction.

The phenomenon of superinduction refers to the process by which high doses (30-180 microM) of the protein synthesis inhibitors Puromycin (PM) or Cycloheximide (CHX) augment and stabilize mRNA transcript levels through mechanisms which are dependent on the complete inhibition of protein synthesis. The current study undertaken in HL-60 leukaemic cells has dissociated the protein synthesis-inhibitory effects of PM and CHX from their c-myc mRNA superinducing effects. When employed at concentrations which were sub-inhibitory with respect to protein synthesis (0.2 microM), PM and CHX nevertheless elicited the phenomenon of superinduction, possibly through mechanisms related to intracellular signalling.

Cycloheximide↗
PubMed1975

[Cycloheximide has no effect on the conditioning of the uterus for implantation by certain ovarian steroids].

Cycloheximide was unable to induce or inhibit the appearance of the refractory state to decidualization which is normally obtained by a small dose of oestrogen given to the progesterone-dominated uterus. Neither was this inhibitor capable of preventing progesterone from sensitizing the uterus to decidualizing stimuli. These results suggest that certain effects of luteal steroids in endometrial cells do not depend on RNA translation.

Animals↗
PubMed1993

Hormone response complex in a novel abscisic acid and cycloheximide-inducible barley gene.

The phytohormone, abscisic acid (ABA), plays a variety of roles during seed development and in the plant's response to environmental stresses. To study the molecular action of ABA, we have isolated a single copy ABA-induced gene, HVA22, which is mapped to barley chromosome 1. The HVA22 gene can be induced by either ABA or the protein synthesis inhibitor, cycloheximide, and addition of both inducers to barley aleurone layers has a synergistic effect on the expression of this gene. Sequence comparison indicates that the HVA22 gene product is highly homologous to the product of human DP1 gene, which is likely to contribute to colorectal tumorigenesis. The hormonal regulation of HVA22 expression has been studied, and there appear to be at least three elements, two located in the promoter and one in the first intron, which are essential for the high level of ABA induction of HVA22 expression. Among the promoter elements is a homolog of ABA response element, which has been shown to be important in the expression of other ABA-induced genes in plants. We suggest that the barley HVA22 gene product is likely a regulatory protein, and the ABA induction of this gene requires the action of a complex set of hormone response elements.

Abscisic Acid↗
PubMed1976

TRH induced thyroxine release from thyroid: its prevention by thyroxine influenced by actinomycin D and cycloheximide.

Male rats of a final weight 350-400 g were fed low iodine diet for 4 weeks and injected radioiodide for 6 days prior to the experiment. They were anesthetized with pentobarbiturate and external arteriovenous shunt was made with the aid of thin polyethylene tubing to collect frequent blood samples while maintaining isovolemia as previously described. The injection of 20 mug synthetic TRH into carotic artery in rostral direction resulted in an increase of plasma thyroxine radioactivity showing a maximum at 120 min after the injection. This increase was prevented with the aid of i.v. injection 20 mug L-thyroxine at 20-180 min before TRH administration. Moreover, the preventive effect of thyroxine was completely blocked by the i.v. injection of actinomycin D (0.8 mg/kg) 60 min before thyroxine, while the administration of cycloheximide (4 mg/kg), at the same time, was without effect. The mechanism of this phenomenon remains to be further elucidated.

Animals↗
PubMed1993

Differential action of cycloheximide and activation stimuli on transcription of tumor necrosis factor-alpha, IL-1 beta, IL-8, and P53 genes in human monocytes.

In the present study we have analyzed superinduction of TNF-alpha mRNA and enhancement of TNF-alpha gene transcription by cycloheximide (Chx) in human blood monocytes isolated by continuous Percoll gradient and activated in vitro. In the same monocyte cultures, we have compared the rate of gene transcription of TNF-alpha, IL-1 beta, IL-8, and the P53-antioncogene under the influence of plastic adherence, Staphylococcus aureus Cowan 1 (SAC), and Chx added at different times of monocyte culture. It was shown that the cytokine genes have low or negligible transcriptional activity in freshly isolated monocytes, whereas P53 gene transcription was constant in freshly isolated and in vitro-stimulated cells. Transcription of the IL-1 beta and IL-8 genes was induced by adherence and was not more enhanced by SAC. Transcription of the TNF-alpha gene was not induced by adherence. Chx added at the beginning of the monocyte culture did not block TNF-alpha or IL-1 beta gene transcription. IL-8 gene transcription, however, was abrogated by Chx. Addition of SAC to monocyte culture containing Chx caused significant enhancement of TNF-alpha gene transcription. Addition of Chx after 2.5 or 4 h of SAC activation caused "superinduction" of TNF-alpha mRNA and enhancement of TNF-alpha gene transcription. The data imply that TNF-alpha gene transcription in activated human monocytes might be regulated by both positive and negative regulatory factors that differ in their stability and protein synthesis dependence. In addition, results demonstrate that TNF-alpha, IL-1 beta, IL-8, and p53 genes in human monocytes are differently regulated.

Cells, Cultured↗
PubMed1995

Cycloheximide induces nitric oxide synthase mRNA in vascular smooth muscle cells by prolonging mRNA lifetime.

Bacterial lipopolysaccharide (LPS) and other immunostimulants induce an isoform of NO synthase (iNOS) in vascular smooth muscle (VSM) which produces large quantities of NO and profound vasodilation; this process has been implicated as the cause of gram-negative septic shock. Although regulation of iNOS has been considered to occur at the level of transcription, it is unclear whether post-transcriptional events also contribute to changes in iNOS mRNA expression. We show that cycloheximide (CH), an inhibitor of protein synthesis, induces iNOS mRNA in VSM and potentiates the induction of iNOS mRNA caused by LPS. For many early-response genes, protein-synthesis inhibitors enhance mRNA levels by increasing mRNA stability. Since iNOS mRNA contains multiple copies of a consensus sequence (AUUUA) in common with these eary-response genes and responsible for mRNA destabilization, we tested whether CH induces iNOS mRNA by prolonging mRNA lifetime. In the absence of CH, iNOS mRNA decayed with biphagic kinetics and a half-life of 2 h. In the presence of CH, half-life was prolonged to approximately 7 h. Our observations indicate that in VSM the stability of iNOS mRNA may be under the control of a labile protein factor which awaits identification and characterization. Regulation of mRNA lifetime represents a novel site for control of iNOS gene expression.

Animals↗