Effets de la carence en sodium sur la cytologie de la cyanobactérie Anabaena cylindrica Lemm

1989 ◽  
Vol 35 (2) ◽  
pp. 322-328 ◽  
Author(s):  
Monique Roussard-Jacquemin
Keyword(s):  
Nitrate Uptake ◽  
Cell Types ◽  
Ultrastructural Changes ◽  
Anabaena Cylindrica ◽  
Sodium Deficiency ◽  
Heterocyst Differentiation ◽  
Akinete Differentiation ◽  
Cyanobacterium Anabaena ◽  
Enriched Cultures ◽  
Further Development

The effects of sodium deficiency on the distribution and the ultrastructural aspect of the various cell types in the filaments were studied during growth of Anabaena cylindrica (strain 1403/2A) in presence of different amounts of nitrate (0, 1 or 10 mequiv./L). Visible symptoms such as chlorosis and reduced growth were clearly apparent several days after inoculation only when nitrate was present in the medium. The filaments broke up and contained exclusively vegetative cells rich in polyglucan granules and showing ultrastructural analogies with akinetes. In absence of sodium increasing nitrate uptake and nitrite efflux were observed in nitrate-enriched cultures (10 mequiv./L). The amount of excreted nitrite was too low to explain the described disturbances. The needs for sodium were lower for cultures without added nitrate. However, whatever the medium, the sodium deficiency brought about a delay in heterocyst differentiation without detrimental effect to the further development of cultures.Key words: cyanobacterium, Anabaena cylindrica, sodium deficiency, heterocyst differentiation, akinete differentiation, ultrastructural changes, nitrate uptake, nitrite efflux.

scholarly journals Regulation of CO2 on heterocyst differentiation and nitrate uptake in the cyanobacterium Anabaena sp. PCC 7120

2005 ◽  
Vol 98 (3) ◽  
pp. 693-698 ◽  
Author(s):  
R.-J. Kang ◽  
D.-J. Shi ◽  
W. Cong ◽  
Z.-L. Cai ◽  
F. Ouyang
Keyword(s):  
Nitrate Uptake ◽  
Heterocyst Differentiation ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

scholarly journals Heterocyst differentiation and cell division in the cyanobacterium Anabaena cylindrica: effect of high light intensity

1981 ◽  
Vol 49 (1) ◽  
pp. 341-352
Author(s):  
D.G. Adams ◽  
N.G. Carr
Keyword(s):  
Cell Division ◽  
Light Intensity ◽  
High Light Intensity ◽  
High Light ◽  
Anabaena Cylindrica ◽  
Fixed Nitrogen ◽  
Heterocyst Differentiation ◽  
Short Period ◽  
Cyanobacterium Anabaena ◽  
Normal Light

Heterocyst differentiation in the cyanobacterium Anabaena cylindrica is initiated by the removal of fixed nitrogen from the medium. These specialized cells occur singly at regular intervals within filaments of vegetative cells. Incubation of cultures for periods of up to 12 h immediately prior to or following removal of fixed nitrogen, at a light intensity (500 mi Einsteins cm-2 s-1) approximately 10-fold higher than that required for optimum growth, resulted in the differentiation of pairs of adjacent (double) heterocysts. The frequency of double heterocysts was proportional to the length of the period of high light intensity. During growth at normal light intensity approximately 5% of cell divisions were symmetrical, but this increased more than 3-fold during 10-h incubation at high light intensity. The frequency of dividing cells remained constant during this period, but increased rapidly on return to normal light. The frequency of double heterocysts was reduced if a period of incubation at normal light intensity was interposed between the 12-h period at high light intensity and transfer to nitrogen-free medium. A period of 8 h normal light was required to reduce the frequency of double heterocysts to control values, and this corresponded to the length of time needed for the frequency of symmetrical divisions to return to control levels following 12 h at high light intensity. We confirm that cell division in Anabaena cylindrica is asymmetrical and conclude that the presence of double heterocysts results from an increase in the symmetry of cell division during incubation at high light intensity. The results also support the finding of previous workers that a cell is only susceptible to differentiation during a short period following its formation. During the period of high light the rate of doubling of the absorbance of the culture at 750 mn increased from 24 h to approximately 10 h and decreased to more than 100 h on return to normal light. The very high rate could be explained by increases in the volume and granular content of cells during incubation at high light intensity and did not represent an equivalent increase in the rate of cell division.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

scholarly journals The pathways of assimilation of 13NH4+ by the cyanobacterium, Anabaena cylindrica.

1977 ◽  
Vol 252 (21) ◽  
pp. 7894-7900
Author(s):  
J.C. Meeks ◽  
C.P. Wolk ◽  
J. Thomas ◽  
W. Lockau ◽  
P.W. Shaffer ◽  
...  
Keyword(s):  
Anabaena Cylindrica ◽  
Cyanobacterium Anabaena

Light-induced transitions in the redox state of thioredoxin in the N2-fixing cyanobacterium Anabaena cylindrica

1986 ◽  
Vol 850 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Allan J. Darling ◽  
Peter Rowell ◽  
William D.P. Stewart
Keyword(s):  
Redox State ◽  
Anabaena Cylindrica ◽  
Cyanobacterium Anabaena

scholarly journals Manipulation of Pattern of Cell Differentiation in a hetR Mutant of Anabaena sp. PCC 7120 by Overexpressing hetZ Alone or with hetP

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 60 ◽  
Author(s):  
He Zhang ◽  
Xudong Xu
Keyword(s):  
Cell Differentiation ◽  
Peptide Inhibitor ◽  
Filamentous Cyanobacterium ◽  
Heterocyst Differentiation ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

In the filamentous cyanobacterium, Anabaena sp. PCC 7120, single heterocysts differentiate at semi-regular intervals in response to nitrogen stepdown. HetR is a principal regulator of heterocyst differentiation, and hetP and hetZ are two genes that are regulated directly by HetR. In a hetR mutant generated from the IHB (Institute of Hydrobiology) substrain of PCC 7120, heterocyst formation can be restored by moderate expression of hetZ and hetP. The resulting heterocysts are located at terminal positions. We used a tandem promoter, PrbcLPpetE, to express hetZ and hetP strongly in the hetR mutant. Co-expression of hetZ and hetP enabled the hetR mutant to form multiple contiguous heterocysts at both terminal and intercalary positions. Expression of hetZ, alone resulted in terminally located heterocysts, whereas expression of hetP, alone produced enlarged cells in strings. In the absence of HetR, formation of heterocysts was insensitive to the peptide inhibitor, RGSGR.

Purification and Properties of Nitrogenase from the Cyanobacterium, Anabaena cylindrica

1979 ◽  
Vol 98 (1) ◽  
pp. 275-284 ◽  
Author(s):  
Patrick C. HALLENBECK ◽  
Paul J. KOSTEL ◽  
John R. BENEMANN
Keyword(s):  
Anabaena Cylindrica ◽  
Purification And Properties ◽  
Cyanobacterium Anabaena

Molecular heterogeneity of ferredoxin:NADP+ oxidoreductase from the cyanobacterium Anabaena cylindrica

1981 ◽  
Vol 657 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Peter Rowell ◽  
Jesus Diez ◽  
Shree K. Apte ◽  
William D.P. Stewart
Keyword(s):  
Molecular Heterogeneity ◽  
Anabaena Cylindrica ◽  
Cyanobacterium Anabaena

Effect of Tryptophan Analogues on Lipid Metabolism in the Cyanobacterium Anabaena cylindrica

1979 ◽  
Vol 7 (6) ◽  
pp. 1268-1269 ◽  
Author(s):  
WITOLD J. KREPSKI ◽  
TERENCE J. WALTON
Keyword(s):  
Lipid Metabolism ◽  
Anabaena Cylindrica ◽  
Cyanobacterium Anabaena ◽  
Tryptophan Analogues
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