Putrescine stimulates DNA synthesis in intestinal epithelial cells

1989 ◽  
Vol 257 (1) ◽  
pp. G145-G150 ◽  
Author(s):  
D. D. Ginty ◽  
D. L. Osborne ◽  
E. R. Seidel
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Rna Synthesis ◽  
Thymidine Incorporation ◽  
Intestinal Epithelial ◽  
Maximal Stimulation ◽  
Time Period ◽  
Cultured Epithelial Cells ◽  
Protein And Rna Synthesis ◽  
Rna And Protein Synthesis

Experiments were designed to examine the effects of exogenously supplied putrescine on the synthesis of DNA, RNA, and protein in cultured epithelial cells (IEC-6). Putrescine increased aphidicolin-sensitive DNA synthesis at concentrations as low as 0.3 microM putrescine with maximal stimulation (267% control) at 10 microM. This response appeared to be an effect of increases in the intracellular concentration of putrescine as the intracellular levels of spermidine and spermine did not change over the time period examined. Furthermore, pulse-chase experiments revealed that putrescine that entered the cell was not metabolized to another polyamine or degraded. In addition, 10 microM putrescine enhanced both cycloheximide-sensitive lysine incorporation and actinomycin D-sensitive uridine incorporation, indexes of protein and RNA synthesis, respectively. Incorporation of both lysine and uridine was maximal 12 h after the addition of putrescine, whereas thymidine incorporation was still increasing at 24 h, the longest time point examined. These data suggest that putrescine synthesis and/or transport during mucosal proliferation is directly involved in the stimulation of epithelial DNA, RNA, and protein synthesis.

ANG II stimulates PKC-dependent ERK activation, DNA synthesis, and cell division in intestinal epithelial cells

2003 ◽  
Vol 285 (1) ◽  
pp. G1-G11 ◽  
Author(s):  
Terence Chiu ◽  
Chintda Santiskulvong ◽  
Enrique Rozengurt
Keyword(s):  
Cell Cycle ◽  
Epithelial Cells ◽  
Dna Synthesis ◽  
Phorbol Esters ◽  
Thymidine Incorporation ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Ang Ii ◽  
Erk Activation ◽  
Pkc Activation

PKC, a major target for the tumor-promoting phorbol esters, has been implicated in the signal transduction pathways that mediate important functions in intestinal epithelial cells, including proliferation and carcinogenesis. With the use of IEC-18 cells arrested in G0/G1, addition of phorbol esters resulted in a modest increase in [3H]thymidine incorporation and a slight shift toward the S and G2/M phases of the cell cycle, whereas the combination of EGF and phorbol 12,13-dibutyrate (PDB) synergistically stimulated DNA synthesis. To investigate the effects of receptor-mediated PKC activation on mitogenesis, we demonstrated that ANG II induced ERK activation, a response completely blocked by pretreatment with mitogen/extracellular signal-regulated kinase inhibitors or specific PKC inhibitors. Furthermore, ANG II stimulated an over threefold increase in [3H]thymidine incorporation that was corroborated by flow cytometric analysis of the cell cycle to levels comparable to that achieved by the combination of EGF and PDB. Taken together, our results indicate that receptor-mediated PKC activation, as induced by ANG II, transduces mitogenic signals leading to DNA synthesis and cell proliferation in IEC-18 cells.

Inhibition of pleomorphism by protein and ribonucleic acid inhibitors

1969 ◽  
Vol 15 (11) ◽  
pp. 1263-1266 ◽  
Author(s):  
Deana T. Klein ◽  
Carol B. Runne
Keyword(s):  
Dna Synthesis ◽  
Ribonucleic Acid ◽  
Mycelial Growth ◽  
Rna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Trichophyton Mentagrophytes ◽  
Protein And Rna Synthesis ◽  
Specific Inhibitors

The granular strain of Trichophyton mentagrophytes (M12-4) was grown in the presence of specific inhibitors of protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) synthesis. Those inhibitors which block protein and RNA synthesis inhibit mutant pleomorphic patch formation. Inhibitors of DNA synthesis had no effect on the visible expression of the mutant patches. Data presented suggest that initiation of the pleomorphic patch is not inhibited, but rather that mycelial growth is blocked.

scholarly journals MACROMOLECULAR SYNTHESES RELATED TO THE REPRODUCTIVE CYST OF TETRAHYMENA PATULA

1973 ◽  
Vol 59 (3) ◽  
pp. 615-623 ◽  
Author(s):  
P. R. Gabe ◽  
L. E. de Bault
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Generation Time ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Tritiated Thymidine ◽  
Growth Cycle ◽  
The Third ◽  
Rna And Protein Synthesis ◽  
The Mean

Macromolecular syntheses in encysted Tetrahymena patula were studied using Feulgen fluorescence cytophotometry, autoradiography, and inhibitors of RNA and protein synthesis. Cycloheximide significantly depressed protein synthesis and D-actinomycin effectively blocked RNA synthesis. Under these conditions, the cells within the cyst were unable to divide. Both cytophotometric measurements and autoradiographic data with tritiated thymidine show that DNA synthesis does not occur during the encystment divisions. Excysted cells placed in nutrient broth medium showed a prolonged generation time after the first cell growth cycle, and by the third generation the mean DNA content per cell was almost triple that of starved excysted cells. These findings indicate that (a) the encystment divisions require RNA and protein synthesis, which are apparently effected through turnover, (b) the encystment division cycles occur in the absence of DNA synthesis, and (c) excysted cells placed in culture medium may go through more than one DNA replication per cell cycle.

Inhibition of protein synthesis by zinc: comparison between protein synthesis and RNA synthesis

1998 ◽  
Vol 17 (12) ◽  
pp. 661-667 ◽  
Author(s):  
Udo Ingbert Walther ◽  
Johannes Schulze ◽  
Wolfgang Forth
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
A549 Cells ◽  
Zinc Toxicity ◽  
Alveolar Type ◽  
Time Curve ◽  
Synthesis Inhibition ◽  
Protein And Rna Synthesis ◽  
Rna And Protein Synthesis

Inhalation of zinc fumes may lead to the acute respiratory distress syndrome. The mechanisms of pulmonary zinc toxicity are not yet understood. Therefore we investigated zinc-dependent depression of protein and RNA synthesis in rat and human lung cell lines. 1 After exposure to 120 or 150 mmol/l zinc, RNA synthesis as assessed by uridine incorporation decreased by 60-70% between 0 and 2 h exposition in rat alveolar type II cells (L2 cells) and human fibroblast-like cells (11Lu and 16Lu cells), and by 90% between 0 and 4 h in carcinoma-derived cells (A549 cells). 2 After 2 h exposure, L2, 11Lu, and 16Lu cells were half-maximally inhibited by 50 mmol/l zinc, whereas A549 cells were more resistant with half-maximal inhibition at 100 mmol/zinc. 3 Protein and RNA synthesis was inhibited in parallel in L2, 11Lu, and A549 cells as indicated by simultaneous determination of uridine and amino acid incorporation. In 16Lu cells, the decline in protein synthesis preceded RNA synthesis inhibition. Pretreatment with RNA synthesis inhibitors (amanitin or actinomycin D) had no effect on time curve and intensity of RNA synthesis inhibition. Taken together, our results indicate that the suppression of RNA and protein synthesis likely are independent phenomena, due to direct zinc effects on these biosynthetic pathways.

scholarly journals Evidence that the Synchronized Production of New Basal Bodies is not Associated with Dna Synthesis in Stentor Coeruleus

1972 ◽  
Vol 11 (2) ◽  
pp. 621-637
Author(s):  
K. B. YOUNGER ◽  
S. BANERJEE ◽  
J. K. KELLEHER ◽  
M. WINSTON ◽  
LYNN MARGULIS
Keyword(s):  
Dna Synthesis ◽  
Ethidium Bromide ◽  
Basal Body ◽  
Actinomycin D ◽  
Thymidine Incorporation ◽  
Basal Bodies ◽  
Rna And Protein Synthesis ◽  
Stentor Coeruleus ◽  
Body Production ◽  
Dna Synthesis Inhibitors

Stentors were induced to produce synchronously thousands of new ciliated oral membranellar band basal bodies in less than 3 h. DNA synthesis does not accompany this process, as determined by [3H]thymidine incorporation into isolated bands and by sensitivity to DNA synthesis inhibitors (mitomycin C, ethidium bromide, cytosine arabinoside and hydroxyurea). Yet DNA could be detected in the cortex and the band at basal body sites by autoradiography. Since [3H]thymidine incorporation into membranellar band was eliminated in concentrations of ethidium bromide that had no effect on basal body formation, the previous reports of ciliate kinetosomal (basal body) DNA are interpreted as due to mitochondrial contamination. Specific cortical patterns of DNA that could have been easily misinterpreted as basal body-related were especially apparent in autoradiographs using [3H]actinomycin D as a ‘stain’. In no experiment involving induced basal body regeneration could evidence be found for a correlation between new basal body production and DNA synthesis; RNA and protein synthesis correlated with basal body and cilia regeneration were, however, easily detected by the same techniques. We concluded that there is no evidence that basal body DNA synthesis is required for new basal body production.

scholarly journals Identification of a Novel Virulence Factor in Clostridium Difficile That Modulates Toxin Sensitivity of Cultured Epithelial Cells

2011 ◽  
Vol 79 (9) ◽  
pp. 3810-3820 ◽  
Author(s):  
Masashi Miura ◽  
Haru Kato ◽  
Osamu Matsushita
Keyword(s):  
Clostridium Difficile ◽  
Epithelial Cells ◽  
Culture Filtrate ◽  
Morphological Changes ◽  
Hypothetical Protein ◽  
Intestinal Epithelial ◽  
Content Type ◽  
Cultured Epithelial Cells ◽  
Toxin Sensitivity ◽  
In Cells

ABSTRACTTwo glucosylating toxins named toxins A and B play a role in the pathogenesis ofClostridium Difficileinfection. The interaction of the toxins with host cell factors proceeds to downstream stages of cytotoxic effects in cells, in which involvement of otherC. difficilefactors remains unknown. We utilized culture filtrate ofC. difficilewith a low dilution to characterize the influence of putative minor proteins on the organization of the actin cytoskeleton in cultured epithelial cells and found a previously uncharacterized F-actin aggregated structure, termed “actin aggregate,” at the juxtanuclear region. We reasoned that formation of actin aggregate was due to an additional factor(s) in the culture filtrate rather than the glucosylating toxins, because treatment of purified toxins rarely caused actin aggregate in cells. We focused on a previously uncharacterized hypothetical protein harboring a KDEL-like sequence as a candidate. The product of the candidate gene was detected in culture filtrate ofC. difficileATCC 9689 and was renamed Srl. Purified glutathioneS-transferase-tagged Srl triggered formation of actin aggregate in the cells in the presence of either toxin A or B and enhanced cytotoxicity of each of the two toxins, including decreases in both cell viability and transepithelial resistance of cultured epithelial monolayer, although the recombinant Srl alone did not show detectable cytotoxicity. Srl-neutralized culture filtrate partially inhibited morphological changes of the cells in parallel with decreased actin aggregate formation in the cells. Thus, Srl might contribute to the modulation of toxin sensitivity of intestinal epithelial cells by enhancing cytotoxicity ofC. difficiletoxins.

Pressure stimulates proliferation and DNA synthesis in rat intestinal epithelial cells

Life Sciences ◽  
1997 ◽  
Vol 61 (7) ◽  
pp. 667-672 ◽  
Author(s):  
Masahiko Hirokawa ◽  
Soichiro Miura ◽  
Takeharu Shigematsu ◽  
Hideo Yoshida ◽  
Ryota Hokari ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial
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