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At least 19 recordsLinked to original sources
PubMed1999

[Genetic effects of mitotic poisons and their modification by heat-shock in strains of Drosophila melanogaster having defective adaptive response].

Teratogenic effect of two mitotic poisons, griseofulvin and colchicine, was confirmed. A similar effect of another antimitotic agent, vinblastin, was demonstrated. The teratogenic effect of these poisons is expressed as a reduction of ommatidia in adult flies when the drug is fed to larvae. The highest frequency of phenocopies was recorded in temperature- and mutagen-sensitive strains. The mutagenic activity of vinblastin and griseofulvin was confirmed by the wing-spot test (somatic mutation and recombination test, SMART) in Drosophila melanogaster. In addition, this test demonstrated mutagenic activity of colchicine. All of the mitotic poisons induced small single spots but did not increase frequency of twin spots mwh/flr. Spot frequency was significantly higher in mutagen-sensitive mutants having defective excision repair. Heat shock (45-min exposure at 37 degrees C) decreased the frequency of phenocopies induced by the mitotic poisons. When third-instar larvae were subjected to heat shock prior to drug administration, the frequency of mutant cell clones was significantly reduced. These results indicate participation of heat-shock proteins in the protection of microtubules in actively proliferating cells of D. melanogaster.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Cytogenetic assays for mitotic poisons: the diploid Chinese hamster cell system.

When the diploid Chinese hamster cells (line Don) were treated with Colcemid (final concentrations 0.05 micrograms/ml and 2 mg/ml) for three hours and the mitotic arrest was reversed by washing and reincubation in the control medium, the cells were able to reorganize spindle and divide within 2-4 hr. When the cells were treated with vinblastine (concentrations 10(-6) and 10(-4) M), there was a continuous accumulation of mitoses after vinblastine was removed. At 10(-6) M, a small proportion of anaphase figures was observed in reversed cell populations but at 10(-4) M, there was no anaphase. The results suggest that tubulin was precipitated or destroyed even in cells in interphase. The G2 and S cells were able to complete their cell cycle but were unable to divide because of the lack of microtubules. When recovery was prolonged to 24, 48 and 72 hr, the cell populations exhibited higher percentages of polyploid and aneuploid elements than the control cell populations. There appeared to be a nonrandom increase of the small metacentric than the larger chromosomes. This test system, after protocol improvements, should be useful to assay mitotic poisons that are water soluble or soluble in DMSO.

Animals↗
PubMed1983

Cytogenetic assays for mitotic poisons. The grasshopper embryo system for volatile liquids.

The present study demonstrates the usefulness of grasshopper (Melanoplus sanguinipes) embryos for detecting mitotic arrest and anaphase abnormalities induced by volatile liquids. Eight compounds were tested with this system. Embryos in vivo (intact chorions) were suspended in sealed chambers and the agents, in various amounts, were placed on the bottom of the chambers. The agents, after evaporation, filled the ambient air in which the embryos respired. After a period of exposure, individual embryos were fixed for squash preparations to determine the mitotic index (MI) and the ratio of anaphases to metaphases (A/M). If an agent completely arrested mitosis at metaphase, the A/M ratio would be zero and the MI would be elevated if the agent does not prevent interphase cells from entering mitosis. Two common organic solvents, benzene and toluene, and two common anesthetics, halothane and chloroform, were found to be potent mitotic arrestants in the present system. Colchicine-like mitoses (c-mitoses) were observed in embryos after treatment of the above four agents; all of these agents except toluene were found to induce an accumulation of c-mitoses. Amyl acetate, 95% ethanol, deionized water, and camphor (in 10% ethanol) failed to show mitosis-arresting effects on the embryos. Abnormal anaphases with lagging chromosomes and multipolar spindles were observed in embryos which showed partial metaphase block after exposure to concentrations of benzene lower than that required for a complete block. Benzene, toluene, halothane, and chloroform have been implicated as teratogens and carcinogens, but are negative as mutagens, clastogens, and SCE inducers. Thus, the carcinogenic activity of these compounds appears to result from their action on cell division mechanisms.

Animals↗