Cycloheximide inhibition of the DNA-dependent RNA-polymerase I of Achlyabisexualis

Timberlake, William E.; McDowell, Larry; Griffin, David H.

doi:10.1016/s0006-291x(72)80232-8

Cited by 27 publications

(7 citation statements)

References 11 publications

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“…Protein synthesis inhibitors with different modes of action have been found to alter RNA synthesis over 24 h without reducing Balbiani ring size [3,30]. Reduced puffing in Chironomus nucleoli by cycloheximide has been attributed to inhibition of RNA polymerase I, which specifically synthesizes nucleolar RNA [29,31]. Effects of protein synthesis inhibitors for longer exposures, such as those used in the chromosomal puffing assay (CPA) (48 h), have not been tested.…”

Section: Discussionmentioning

confidence: 99%

Reduced Chromosomal Puffing in Chironomus Tentans as a Biomarker for Potentially Genotoxic Substances

Bentivegna¹,

Cooper²

1993

Environ Toxicol Chem

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Chromosomal puffing in the salivary glands of larval Chironomus tentans was developed as a biomarker for genotoxic substances. Reduced chromosomal puffing was considered an indication of decreased RNA synthesis. Third-or fourth-instar larvae were exposed to test chemicals in an artificial substrate under static conditions. Chromosomes from glands of individual larvae were stained with methyl green and pyronin Y. The widths of Balbiani rings I and I1 (large puffs on chromosome IV) were measured. Three carcinogens with different mechanisms of action were tested, benzo[a]pyrene (BaP), actinomycin D (Act D), and dimethylnitrosamine (DMN). Puff size was statistically reduced by all three chemicals with varying potency. Lowest-observable-effect levels (LOEL) were 0.5 nmol BaP, 6.0 nmol Act D, and 243,000 nmol DMN. The degree of response was influenced by exposure time, applied dose, individual sensitivity, and possibly chemical hydrophobicity. Biomarker specificity was determined by testing a weak carcinogen, benzo[e]pyrene (BeP), and an acutely toxic noncarcinogen, naphthalene (NP). The effective dose of BeP (LOEL = 250 nmol) was four orders of magnitude higher than that of BaP. Only lethal doses of NP had statistically significant effects on puff size, LD50 = 25,000 (34,700) nmol. Approximately 40% of the larvae in our laboratory population appeared tolerant to the effects of BaP. Advantages of this biomarker were its association with a known mechanism of action and measurement of the whole-organism integrated response.

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Section: Discussionmentioning

confidence: 99%

Reduced Chromosomal Puffing in Chironomus Tentans as a Biomarker for Potentially Genotoxic Substances

Bentivegna¹,

Cooper²

1993

Environ Toxicol Chem

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“…Light conditions were provided by Mazda Universal white fluorescent tubes (65/80 W) giving 2.8 W m^^ (1000 lux) which was found to give maximal carotenoid production without actually killing the organism. The mycelium was strained through Miracloth, washed several times with distilled water and homogenized in the PVP buffer of Timberlake et al (1972a) for 1 min with the ultrasonicator Willems Polytron PT 20 st. at high speed.…”

Section: Methodsmentioning

confidence: 99%

“…Isolation of crude nuclear pellet: Cell wall debris was removed by filtration through Miracloth and the homogenate was centrifuged for 10 min at 1500 g. The resulting crude nuclear pellet (Horgen and Griffin 1971a) was used for enzyme isolation. The pellet was suspended in a solubilization buffer (20 mM Tris-base, pH 7.8; 30% glycerol; 6mMMgCl2;lmMNa-EDTA;50mMBME;50mMAS; 10 mg/ml BSA and 0.5 % DOC) and chromatographed on DEAE-cellulose as described by Timberlake et al (1972a). The enzymes were eluted with a linear gradient of AS from 50 to 500 mM.…”

Section: Methodsmentioning

confidence: 99%

“…It is now well known that RNA synthesis varies with different stages of differentiation (Dunham and Cherry 1973). In several eukaryotic organisms (Horgen and Key 1973, Jacob et al 1970, Roeder and Rutter 1969, Adman et al 1972, Higashinakagawa and Muramatsu 1972, Timberlake et al 1972a) different forms of RNA polymerase have been distinguished using DEAE-cellulose chromatography. Two, three and four fractions of RNA polymerases activity have been demonstrated in the different organisms.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Light on the Composition of DNA‐dependent RNA Polymerases of Verticillium agaricinum

Valadon

1974

Physiologia Plantarum

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Four cellular RNA polymerases have been partially purified from cultures of Verticillium agaricinum using DEAE-cellulose chromatography. Polymerases I and II are probably localised in the nucleolus and non-nucleolar portion of the nucleus respectively, while III and IV are probably mitochondrial in origin. DNA stimulation and dependency on the four ribonucleoside triphosphates were shown to be characteristic of all four polymerases. The products of their activity were sensitive to ribonuclease digestion and to KOH hydrolysis. The time course study of all four polymerases showed a linear increase for 1 min followed by a plateau and a rapid decrease after 5 min.Illumination of 4-day-oId cultures increases the activity of RNA polymerase I, II, and III while only that of 1 and III is increased in 7-day cultures. There is a similar increase in the amount of carotenoids produced by 4-and 7-day-old illuminated cultures. It is tempting therefore to suggest that ribosomes or mitochondria or both may be implicated in light-induced cartogenesis.

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“…Cyclohexamide may be involved in the inhibition of factors involved in the initiation of RNA polymerase activity [43]. More specifically, the reduced puffing in Chironomus nucleoli by CHM has been attributed to inhibition of RNA polymerase I which specifically synthesizes nucleolar RNA [44,45]. Bulky adducts produced by chemicals such as benzo-[a]-pyrene probably reduce puff size by blocking the progress of RNA polymerase along the template [18].…”

Section: Incidence Of Nucleolus Reductionmentioning

confidence: 99%

Teratogenic and Genotoxic Responses of Larval Chironomus Salinarius Group (Diptera: Chironomidae) to Contaminated Sediment

Hudson¹,

Ciborowski²

1996

Environ Toxicol Chem

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Abstract-Chironomids are important indicators of the effects of sediment-bound contaminants. However, cause-effect relationships between contaminant exposure and stress-related indicators other than growth and survival have not been demonstrated. In the laboratory, we conducted 10-d exposures of Chironomus salinarius group Kieffer larvae to mixtures of contaminated (Trenton Channel, Detroit River, MI) sediment diluted with uncontaminated, formulated sediment (sand, sculptor's clay, and potting soil) in ratios of 1:0, 1:1, 1:3, 1:7, 1:15, and 0:1. Larvae were inoculated into either recently mixed sediments or those allowed to age for 7 d. Surviving larvae were examined for mouthpart (mentum) deformities. Giant chromosomes of the salivary glands were examined for reduction in relative nucleolus diameter (RND). Proportions of larvae with mentum deformities and of larvae with reduced RND increased linearly with each doubling of concentration of contaminated sediment. Deformities and RND reduction in individual larvae were independent responses. Incidences of deformities at low contamination doses were much greater for recently mixed sediments than for more aged sediments. Sediment age did not affect incidence of reduced RND except in the most contaminated treatment. Mentum deformities and reduced RND are quantifiable sublethal attributes reflecting stress responses to sediment contamination that can complement more traditional measures (survival and growth) in chironomid sediment bioassays.

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Cycloheximide inhibition of the DNA-dependent RNA-polymerase I of Achlyabisexualis

Cited by 27 publications

References 11 publications

Reduced Chromosomal Puffing in Chironomus Tentans as a Biomarker for Potentially Genotoxic Substances

Reduced Chromosomal Puffing in Chironomus Tentans as a Biomarker for Potentially Genotoxic Substances

The Effect of Light on the Composition of DNA‐dependent RNA Polymerases of Verticillium agaricinum

Teratogenic and Genotoxic Responses of Larval Chironomus Salinarius Group (Diptera: Chironomidae) to Contaminated Sediment

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