Effect of B-chromosomes on the duration of mitotic cycle in pearl millet

Summary Effect of B-chromosomes on the duration of the mitotic cycle was studied by a colchicine shock method in the root-tip cells of pearl millet (Pennisetum typhoides). 3 B-chromosomes were found to have very little effect, whereas 5 B-chromosomes resulted in an increase of the duration by about 39%.This investigation was financed by the University Grants Commission, New Delhi.     

Melatonin antagonizes colchicine-induced mitotic arrest

Summary Melatonin, in concentrations up to 10^–3 M, showed no effect on mitosis in cultures of HeLa or KB cells. However, when melatonin at 10^–4 M was preincubated with HeLa cells prior to addition of 10^–7 M colchicine, a reduction in the mitotic index, in comparison to colchicine alone, was observed.This work was supported by PHS Grant No. CA 16425.     

Random chromosome breakage by colchicine inViscum fischeri (Loranthaceae)

Summary When the shoot-tips ofViscum fischeri Engl. were treated with various concentrations of colchicine for different lengths of time, it was found that in this plant chromosome breakage was not localized to centromeric region as reported in other plants. InV. fischeri chromosome breakage occurred at random (simulating X-ray-induced fragmentation). The percentage of breakage increased linearly with respect to time at concentrations 0.1, 0.2, 0.3% but parabolically at 0.5%.Acknowledgment. The authors are grateful to Dr M. A. Hannan of NRC, Ottawa, Canada, for his helpful criticism and suggestions, and to Professor S. K. Imbamba, Chairman, Dept. of Botany, University of Nairobi for laboratory facilities.     

Occurrence of monocentric chromosomes inPieris brassicae L. (Lepidoptera,Pieridae)

Summary Monocentric chromosomes with localized kinetochores were obtained inPieris brassicae (Lepidoptera, Pieridae) by using colchicine treatment and air-drying method.We wish to express our thanks to Dr A.K. Datta-Gupta, Professor and Head of our Department for providing the research facilities and for encouragement.     

Zur Wirkung von Colchiceinamiden an Zellenin vitro undin vivo

Summary Colchiceine-N-mono-methylamide is 3–4 times as active as colchicine as shown by its effect on the mouse-ascites-tumor (Ehrlich) and on fibroblastsin vitro.     

Beeinflussung der Antennendifferenzierung durch Colchicin bei derDrosophilamutanteAristopedia

Summary A decrease in growth rate of the antennal bud by means of colchicine deflects the differentiation of theAristopedia antenna towards an arista.

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DieDrosophilamutanteAristopedia unterscheidet sich von der Wildform durch die Umwandlung der Fühlergeißel (=Arista) in einen Fuß.     

Antimitotic effect of nimbidin — A first report

Summary The antimitotic activity of nimbidin, a drug from the plantMelia azadirecta indica, was assessed by its effect on the meristematic cells of onion root tips. The effect was almost similar to those of colchicine and vinca alkaloids. Recovery trials showed that the drug induces lethal damage in a considerable proportion of treated cells and may hence have applications in cancer chemotherapy.     

Über die Beeinträchtigung der Wirkung von Spindelgiften in der Zellkultur durch menschliches Serum sowie durch Seren verschiedener Tierspezies

Summary Chick embryo fibroblasts, cultivatedin vitro, require higher concentrations of podophyllotoxin derivatives for complete mitotic arrest when the medium contains human adult or cord serum than when it contains horse, bovine, guinea pig, rat, mouse, or cock serum. This difference is due to a higher binding capacity of human serum for these compounds. No such difference was found with a colchicine and a peltatin derivative.     

Effects of isaxonine phosphate and analogs on fibroblast metabolism in culture

Summary Human skin fibroblasts in confluent cultures were incubated for 24 h in the presence of isaxonine phosphate (Nerfactor) and several related factors. The incorporation of¹⁴C-proline into secreted proteins and the release of collagen into the medium were inhibited. When the cells incubated for an additional period of 24 h after thorough washing, protein and collagen syntheses were found to be identical to those of controls, demonstrating that the inhibition of protein synthesis was independent of any toxic effect. When cells were incubated in the presence of both isaxonine and colchicine, the secretion of collagen was more inhibited than by colchicine alone, and proteins accumulated in the cells.     

New patterns of vascular development in roots of Pisum recovering from colchicine treatment

Summary Abnormal vascular patterns were formed in pea roots recovering from a 3-h treatment with 0.025% of colchicine solution. New, often asymmetrical, patterns arose by the formation of additional protoxylem poles; later the patterns converted to a normal symmetrical tetrarch or triarch condition.Acknowledgment. I. thank Professor L. W. Roberts, University of Idaho, for the help he gave me during the preparation of this paper.     

Effect of colchicine on polymerization of tubulin from rats, mice, hamsters and guinea-pigs.

Colchicine-inhibition of polymerization of tulbulin from rats, mice, golden hamsters and guinea-pigs was studied to determine if species differences in tubulin sensitivity to colchicine might parallel species variation in colchicine toxicity. It was found that polymerization of tubulin is nearly equally sensitive to colchicine in all four species.     

Behaviour ofDrosophila melanogaster is affected by drugs

Summary Reserpine, colchicine and Rb⁺ ions exerted specific effects on sexual behaviour and locomotor activity of the fruit fly. Neuroleptics and antidepressants were inactive.     

Effect of colchicine on polymerization of tubulin from rats,mice, hamsters and guinea-pigs

Summary Colchicine-inhibition of polymerization of tubulin from rats, mice, golden hamsters and guinea-pigs was studied to determine if species differences in tubulin sensitivity to colchicine might parallel species variation in colchicine toxicity. It was found that polymerization of tubulin is nearly equally sensitive to colchicine in all four species.This work was supported by PHS Grant No. CA 16425.     

Colchicine inhibition of ADH effect on frog skin permeability

ADH and AMPc enhance both thiourea unidirectional fluxes in frog skin. This effect is completely abolished by colchicine pretreatment. The ADH increase of thiourea discharge with or without colchicine led us to suppose that colchicine does not directly affect ADH action on outer membrane permeability, but exerts its effects on a site which is limiting for the ADH action on transepithelial permeability.     

Response of murine spermatocytes to the metaphase-arresting effect of several mitotic arrestants

Three mitotic arrestants, colchicine, Colcemid and vinblastine, were evaluated for their effects on producing meiotic arrest in the laboratory mouse. Colchicine is the most effective and its effect is both dose- and time-dependent. Treatment of mice with 40 mg/kg of colchicine for 3 h resulted in drastic improvement of the yield and quality of M-II figures. This treatment did not appear to increase the aneuploidy frequency in M-II's.     

Colchicine inhibition of ADH effect on frog skin permeability

Summary ADH and AMPc enhance both thiourea unidirectional fluxes in frog skin. This effect is completely abolished by colchicine pretreatment. The ADH increase of thiourea discharge with or without colchicine led us to suppose that colchicine does not directly affect ADH action on outer membrane permeability, but exerts its effects on a site which is limiting for the ADH action on transepithelial permeability.The present work has been supported by C.N.R., Rome.     

Zur entwicklungsphysiologischen Wirkungsanalyse von antimitotischen Stoffen

Summary The cleavage mitoses of eggs of the fresh-water oligochete Tubifex may be irreversibly blocked, if treated during a relatively short time by solutions of certain antimitotic substances (benzoquinone, naphthoquinone or colchicine). It is also possible to inhibit tail regeneration in tadpoles of Rana or Xenopus by a single colchicine treatment during only 30 to 60 minutes. It is discussed whether this is due to irreversible loss of regeneration capacity or simply to an inhibition of the first regeneration processes.     

Antagonistic effects of pemoline to colchicine and caffeine.

Pemoline, the constituent of Tradon, is able to slow down the decrease of the mitotic index caused by 0.1% caffeine in roots of Vicia faba, and mitotic aberrations are reduced. With 0.005% colchicine and 3 x 10(-4) g/ml pemoline, no metaphase-accumulation can be observed, and anaphase-disorder is delayed.     

Effects of isaxonine phosphate and analogs on fibroblast metabolism in culture

Human skin fibroblasts in confluent cultures were incubated for 24 h in the presence of isaxonine phosphate (Nerfactor) and several related factors. The incorporation of 14C-proline into secreted proteins and the release of collagen into the medium were inhibited. When the cells were incubated for an additional period of 24 h after thorough washing, protein and collagen syntheses were found to be identical to those of controls, demonstrating that the inhibition of protein synthesis was independent of any toxic effect. When cells were incubated in the presence of both isaxonine and colchicine, the secretion of collagen was more inhibited than by colchicine alone, and proteins accumulated in the cells.     

Action of diphenylhydantoin on chromosomes

The effect of diphenyl hydantoin, (DPH) a nonbarbituate anticonvulsant drug, on chromosomes and fertility was tested in cultured human lymphocytes, mouse fertility, and rat maternal marrow chromosomes and fetal development. Whole human blood from 5 male and 5 female subjects was cultured for 68 hours with phytohemagglutinin, then incubated for 2 hours in isotonic salts with .05-.3 mg per ml DPH, .02 mcg per ml colchicine, or .4 mg per ml sodium diethylbarbiturate. The mean number of metaphases per 1000 stimulated cells was 10.0 in controls, 40.3 with colchicine, 27.9 with diethylbarbiturate, and 30.5 with .25 mg DPH per ml. Both diphenylbarbiturate and DPH produced linear dose effect curves. These results were demonstrated not to be due to urea, since there were no differences in urea content, with a 2 hour urease micromethod. Mouse fertility was totally inhibited in 6 virgin mice given .1mg DPH daily for 10 days compared to 41 pups both of 6 control mice. In 6 pregnant rats given 25 mg DPH per 100 gm/orally 4 times daily for 2 days on gestation Days 7 and 8, there were 5 rats with all fetuses resorbed and 1 rat with 3 living and several resorptions. 6 controls had 6-14 normal fetuses each. 50 metaphase plates from each rat's femoral marrow and each fetus were examined 2 hous after injecting .3 mg colchicine per 100 gm. 30% of the metaphase cells from treated females and fetuses showed strongly contracted chromosomes and reduced number os "pulverized" chromosomes. These phenomena may have been due to inhibition by DPH of folic acid metabolism which is involved in purine synthesis.