Reduced chromosomal puffing in Chironomus tentans as a biomarker for potentially genotoxic substances

Journal Article · Tue Jun 01 04:00:00 EDT 1993 · Environmental Toxicology and Chemistry; (United States)

DOI:https://doi.org/10.1897/1552-8618(1993)12[1001:RCPICT]2.0.CO;2· OSTI ID:5811489

Bentivegna, C S ^[1]; Cooper, K R ^[2]

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1. Rutgers, The State Univ., New Brunswick, NJ (United States). Dept. of Environmental Sciences
2. Rutgers, The State Univ., Piscataway, NJ (United States). Joint Graduate Program in Toxicology

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 1 and 2 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 were 0.5 nmol BaP, 6.0 nmol Act D, and 24443,000 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 BaP 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 nmol. Approximately 40% of the larvae in the 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.

• OSTI ID: 5811489
• Journal Information: Environmental Toxicology and Chemistry; (United States), Journal Name: Environmental Toxicology and Chemistry; (United States) Vol. 12:6; ISSN ETOCDK; ISSN 0730-7268
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACTINOMYCIN
AMINES
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTIMITOTIC DRUGS
ANTINEOPLASTIC DRUGS
AROMATICS
ARTHROPODS
BENZOPYRENE
BIOLOGICAL EFFECTS
BIOLOGICAL MARKERS
CHROMOSOMAL ABERRATIONS
CHROMOSOMES
CONDENSED AROMATICS
DIPTERA
DRUGS
FLIES
GENETIC EFFECTS
HYDROCARBONS
INSECTS
INVERTEBRATES
MUTATIONS
NAPHTHALENE
NITROSAMINES
NITROSO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
SENSITIVITY