THE ANTIALGAL ACTIVITY OF ACTI-DIONE

1958 ◽  
Vol 4 (4) ◽  
pp. 399-408 ◽  
Author(s):  
Alfons Zehnder ◽  
Elwyn O. Hughes
Keyword(s):  
Cell Division ◽  
Cell Density ◽  
Inhibiting Effect ◽  
Antialgal Activity ◽  
Low Concentrations ◽  
Haematococcus Lacustris

Acti-dione inhibits the growth of Chlorophyceae, Xanthophyceae, and Bacillariophyceae at concentrations of 50 p.p.m. or less, but much higher concentrations have no inhibiting effect on the development of Myxophyceae. At concentrations of 50 to 100 p.p.m., it has been successfully employed in the isolation of unialgal cultures of two species of Myxophyceae. Haematococcus lacustris, a species of Chlorophyceae, has the lowest tolerance to Acti-dione of any microorganism yet found. Acti-dione interferes with cell division of this species at very low concentrations (0.016 to 0.032 p.p.m.), but much higher concentrations are required to inhibit motility. The effect of Acti-dione may be algistatic or algicidal depending upon the concentration used, the duration of the exposure, the species concerned, and the cell density.

ABOUT SOME PECULIARITIES OF THE PHYSIOLOGICAL HETEROGENEITY OF THE POPULATION OF SCENEDESMUS QUADRICAUDA (TURP.) BREB. IN THE PRESENCE OF LOW CONCENTRATIONS OF METALS

2018 ◽  
pp. 34-43
Author(s):  
V. I. Ipatova ◽  
A. G. Dmitrieva ◽  
О. F. Filenko ◽  
T. V. Drozdenko
Keyword(s):  
Cell Division ◽  
Toxic Effect ◽  
Copper Chloride ◽  
Single Cells ◽  
Physiological State ◽  
Scenedesmus Quadricauda ◽  
Physiological Status ◽  
Lag Phase ◽  
Protective Mechanism ◽  
Low Concentrations

The structure of the laboratory population of green microalgae Scenedesmus quadricauda (Turp.) Breb (=Desmodesmus communis E. Hegew.) was studied at different stages of its growth (lag-phase, log-phase and stationary phase) at low concentrations of copper chloride and silver nitrate by the method microculture, allowing to monitor the state and development of single cells having different physiological status. The response of the culture of S. quadricauda - the change in the number of cells and the fractional composition (the fraction of dividing, «dormant» and dying cells) depended not only on the concentration of the toxicant in the medium, but also on the physiological state of the culture: the level of synchronization and the growth phase. Silver ions at low concentrations had a more pronounced toxic effect on the culture than copper ions at different phases of its development, especially at a concentration of 0.001 mg/l (10-9 M). The main mechanism of the toxic effect of metals is to inhibit the process of cell division. At low concentrations of toxicants, especially at a concentration of 0.001 mg/l, a «paradoxical» effect expressed in the predominance of the fraction of «dormant» cells was revealed. The temporary inhibition of the process of cell division can be regarded as a protective mechanism that allows preserving the integrity of the population and its ability to survive in a changing environment. The obtained data explain the effect of action of low concentrations of substances due to their inclusion in the cell, the subsequent accumulation in the cell and their low excretion.

Inhibiting Effect of Dehydroascorbic Acid on Cell Division in Ascites Tumors in Mice

Pathobiology ◽  
1982 ◽  
Vol 50 (1) ◽  
pp. 34-38
Author(s):  
Eymard Poydock ◽  
D. Reikert ◽  
J. Rice ◽  
L. Aleandri
Keyword(s):  
Cell Division ◽  
Dehydroascorbic Acid ◽  
Inhibiting Effect ◽  
Ascites Tumors

Reduction of the rate of outgrowth, cell density, and cell division following removal of the apical ectodermal ridge of the chick limb-bud

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 1-21
Author(s):  
Dennis Summerbell
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Cell Division ◽  
Cell Density ◽  
Apical Ectodermal Ridge ◽  
Limb Bud ◽  
Short Term ◽  
Density Dependent ◽  
Wing Bud

Removal of the apical ectodermal ridge causes a reduction in the rate of outgrowth of the wing-bud and the loss of distal parts. More specifically it causes a short-term increase in cell density and cell death and a decrease in the rate of cell proliferation. The evidence supports the hypothesis of density-dependent control of cell division and suggests that there may also be a mechanism regulating skeletal length at the time of differentiation. An informal model is presented to explain the observations.

Low concentrations of caffeine induce asymmetric cell division as observed in vitro by means of the CBMN-assay and iFISH

2015 ◽  
Vol 793 ◽  
pp. 71-78 ◽  
Author(s):  
Vasiliki I. Hatzi ◽  
Maria Karakosta ◽  
Katarzyna Barszczewska ◽  
Ioanna Karachristou ◽  
Gabriel Pantelias ◽  
...  
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Low Concentrations ◽  
Cbmn Assay

scholarly journals STUDIES ON THE MECHANISM OF ACTION OF IONIZING RADIATIONS

1952 ◽  
Vol 35 (6) ◽  
pp. 865-871 ◽  
Author(s):  
E. S. Guzman Barron ◽  
S. Louise Seki
Keyword(s):  
Cell Division ◽  
Sperm Cells ◽  
X Rays ◽  
Thiol Compounds ◽  
X Ray ◽  
Arbacia Punctulata ◽  
Inhibiting Effect ◽  
Small Doses ◽  
X Irradiation ◽  
Ionizing Radiations

On x-irradiation of the eggs and sperm of Arbacia punctulata there was inhibition of respiration with relatively large doses, whereas there was an increase with small doses. The dose required to produce an increase of respiration depended on the degree of sensitivity of the cell to the effect of ionizing radiation. Sperm cells were more sensitive; then came fertilized eggs; unfertilized eggs were the least sensitive. The inhibiting effect of x-rays on cell division was observed even on irradiation with x-ray doses which produced an increase of respiration. These results are compared to similar effects produced by thiol reagents and are attributed to oxidation of the thiol compounds in the cell.

scholarly journals A Novel Mechanism, Linked to Cell Density, Largely Controls Cell Division in Synechocystis

2017 ◽  
Vol 174 (4) ◽  
pp. 2166-2182 ◽  
Author(s):  
Alberto A. Esteves-Ferreira ◽  
Masami Inaba ◽  
Toshihiro Obata ◽  
Antoine Fort ◽  
Gerard T.A. Fleming ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Density

Cell Density and Cell Division in the Early Morphogenesis of the Chick Wing

1972 ◽  
Vol 239 (88) ◽  
pp. 24-26 ◽  
Author(s):  
D. SUMMERBELL ◽  
L. WOLPERT
Keyword(s):  
Cell Division ◽  
Cell Density

scholarly journals The LysR-Type Transcriptional Regulator YofA Controls Cell Division through the Regulation of Expression of ftsW in Bacillus subtilis

2007 ◽  
Vol 189 (15) ◽  
pp. 5642-5651 ◽  
Author(s):  
Zuolei Lu ◽  
Michio Takeuchi ◽  
Tsutomu Sato
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Stationary Phase ◽  
Cell Density ◽  
Exponential Growth ◽  
Insertion Mutant ◽  
Regulation Of Expression ◽  
Dependent Growth ◽  
Stationary Phase Analysis ◽  
Final Round

ABSTRACT We have carried out a functional analysis of LysR family transcriptional regulators in Bacillus subtilis. The cell density of cultures of a yofA insertion mutant declined sharply after the end of exponential growth, as measured by optical density at 600 nm. Complementation in trans and analysis of isopropyl-β-d-thiogalactopyranoside (IPTG)-dependent growth of an inducible yofA strain confirmed that YofA contributes to the cell density of a culture after the end of exponential growth. Microscopic observation suggested that cell division is inhibited or delayed in the yofA mutant during entry into stationary phase. Analysis of the transcription of cell division genes revealed that the expression of ftsW is inhibited in yofA mutants, and overexpression of yofA, driven by a multiple-copy plasmid, enhances the induction of ftsW expression. These results suggest that YofA is required for the final round of cell division before entry into stationary phase and that YofA positively regulates ftsW expression. The defects caused by mutation of yofA were suppressed in strains carrying P spac -ftsW in the presence of IPTG. Furthermore, maximal expression of yofA was observed at the onset of stationary phase, which coincided with the maximal ftsW expression. Our data indicate that YofA is involved in cell division through positive regulation of the expression of ftsW in B. subtilis.

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