Isocitrate lyase activity patterns during cell cycle in synchronous cultures of Chlamydomonas reinhardtii (Chlorophyceae)

2010 ◽  
Vol 133 ◽  
pp. 43-64 ◽  
Author(s):  
Ruth Paulson ◽  
Gjert Knutsen ◽  
Svein R. Erga
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii ◽  
Isocitrate Lyase ◽  
Activity Patterns ◽  
Synchronous Cultures ◽  
Lyase Activity

scholarly journals To Divide or Not to Divide? How Deuterium Affects Growth and Division of Chlamydomonas reinhardtii

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 861
Author(s):  
Veronika Kselíková ◽  
Vilém Zachleder ◽  
Kateřina Bišová
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii ◽  
Cell Cycle Progression ◽  
Model Organism ◽  
Cycle Progression ◽  
Synchronous Cultures ◽  
Multiple Fission ◽  
First Choice ◽  
High Doses

Extensive in vivo replacement of hydrogen by deuterium, a stable isotope of hydrogen, induces a distinct stress response, reduces cell growth and impairs cell division in various organisms. Microalgae, including Chlamydomonas reinhardtii, a well-established model organism in cell cycle studies, are no exception. Chlamydomonas reinhardtii, a green unicellular alga of the Chlorophyceae class, divides by multiple fission, grows autotrophically and can be synchronized by alternating light/dark regimes; this makes it a model of first choice to discriminate the effect of deuterium on growth and/or division. Here, we investigate the effects of high doses of deuterium on cell cycle progression in C. reinhardtii. Synchronous cultures of C. reinhardtii were cultivated in growth medium containing 70 or 90% D2O. We characterize specific deuterium-induced shifts in attainment of commitment points during growth and/or division of C. reinhardtii, contradicting the role of the “sizer” in regulating the cell cycle. Consequently, impaired cell cycle progression in deuterated cultures causes (over)accumulation of starch and lipids, suggesting a promising potential for microalgae to produce deuterated organic compounds.

scholarly journals Inhibitor effects during the cell cycle in Chlamydomonas reinhardtii. Determination of transition points in asynchronous cultures.

1975 ◽  
Vol 67 (1) ◽  
pp. 126-135 ◽  
Author(s):  
S H Howell ◽  
W J Blaschko ◽  
C M Drew
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Chlamydomonas Reinhardtii ◽  
Macromolecular Synthesis ◽  
Synchronous Cultures ◽  
Organellar Dna ◽  
Rna And Protein Synthesis ◽  
Transition Points

A wide variety of inhibitors (drugs, antibiotics, and antimetabolites) will block cell division within an ongoing cell cycle in autotrophic cultures of Chlamydomonas reinhardtii. To determine when during the cell cycle a given inhibitor is effective in preventing cell division, a technique is described which does not rely on the use of synchronous cultures. The technique permits the measurement of transition points, the cell cycle stage at which the subsequent cell division becomes insensitive to the effects of an inhibitor. A map of transition points in the cell cycle reveals that they are grouped into two broad periods, the second and fourth quarters. In general, inhibitors which block organellar DNA, RNA, and protein synthesis have second-quarter transition points, while those which inhibit nuclear cytoplasmic macromolecular synthesis have fourth-quarter transition points. The specific grouping of these transition points into two periods suggests that the synthesis of organellar components is completed midway through the cell cycle and that the synthesis of nonorganellar components required for cell division is not completed until late in the cell cycle.

scholarly journals Isocitrate Lyase Activity in Lactobacillus murinus CNRZ 313

1983 ◽  
Vol 66 (6) ◽  
pp. 1232-1236 ◽  
Author(s):  
M.C. Albizzatti de Rivadeneira ◽  
M.C. Manca de Nadra ◽  
A.A. Pesce de Ruiz Holgado ◽  
G. Oliver
Keyword(s):  
Isocitrate Lyase ◽  
Lyase Activity ◽  
Lactobacillus Murinus

Acetate metabolism in Escherichia coli

1978 ◽  
Vol 24 (2) ◽  
pp. 149-153 ◽  
Author(s):  
T. M. Lakshmi ◽  
Robert B. Helling
Keyword(s):  
Isocitrate Dehydrogenase ◽  
Citrate Synthase ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Acetate Metabolism ◽  
Wild Type ◽  
Intermediary Metabolites ◽  
Lyase Activity ◽  
Acetate Medium ◽  
The Glyoxylate Cycle

Levels of several intermediary metabolites were measured in cells grown in acetate medium in order to test the hypothesis that the glyoxylate cycle is repressed by phosphoenolpyruvate (PEP). Wild-type cells had less PEP than either isocitrate dehydrogenase – deficient cells (which had greater isocitrate lyase activity than the wild type) or isocitrate dehydrogenase – deficient, citrate synthase – deficient cells (which are poorly inducible). Thus induction of the glyoxylate cycle is more complicated than a simple function of PEP concentration. No correlation between enzyme activity and the level of oxaloacetate, pyruvate, or citrate was found either. Citrate was synthesized in citrate synthase – deficient mutants, possibly via citrate lyase.

scholarly journals Comprehensive Discovery of Cell-Cycle-Essential Pathways in Chlamydomonas reinhardtii

2018 ◽  
Vol 30 (6) ◽  
pp. 1178-1198 ◽  
Author(s):  
Michal Breker ◽  
Kristi Lieberman ◽  
Frederick R. Cross
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii

Oxygen uptake during the cell cycle of the fission yeast Schizosaccharomyces pombe

1978 ◽  
Vol 33 (1) ◽  
pp. 399-411
Author(s):  
J. Creanor
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Oxygen Uptake ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Nuclear Division ◽  
Synchronous Culture ◽  
Synchronous Cultures ◽  
The Many

Oxygen uptake was measured in synchronous cultures of the fission yeast Schizosaccharomyces pombe. The rate of oxygen uptake was found to increase in a step-wise manner at the beginning of the cycle and again in the middle of the cycle. The increases in rate were such that overall, oxygen uptake doubled in rate once per cell cycle. Addition of inhibitors of DNA synthesis or nuclear division to a synchronous culture did not affect the uptake of oxygen. In an induced synchronous culture, in which DNA synthesis, cell division, and nuclear division, but not ‘growth’ were synchronized, oxygen uptake increased continuously in rate and did not show the step-wise rises which were shown in the selection-synchronized culture. These results were compared with previous measurements of oxygen uptake in yeast and an explanation is suggested for the many different patterns which have been reported.

Sequences controlling transcription of the Chlamydomonas reinhardtii beta 2-tubulin gene after deflagellation and during the cell cycle

1994 ◽  
Vol 14 (8) ◽  
pp. 5165-5174
Author(s):  
J P Davies ◽  
A R Grossman
Keyword(s):  
Cell Cycle ◽  
Chlamydomonas Reinhardtii ◽  
Transcription Initiation ◽  
Chimeric Gene ◽  
Transcriptional Level ◽  
Sequence Motif ◽  
Tubulin Gene ◽  
Rich Region ◽  
Beta 2 ◽  
Encoding Genes

In Chlamydomonas reinhardtii, transcripts from the beta 2-tubulin gene (tubB2), as well as those from other tubulin-encoding genes, accumulate immediately after flagellar excision as well as at a specific time in the cell cycle. Control of tubB2 transcript accumulation following deflagellation is regulated, at least partially, at the transcriptional level. We have fused the tubB2 promoter to the arylsulfatase (ars) reporter gene, introduced this construct into C. reinhardtii, and compared expression of the chimeric gene with that of the endogenous tubB2 gene. After flagellar excision, transcripts from the tubB2/ars chimeric gene accumulate with kinetics similar to those of transcripts from the endogenous tubB2 gene. The tubB2/ars transcripts also accumulate in a cell cycle-specific manner; however, chimeric transcripts are more abundant earlier in the cell cycle than the endogenous tubB2 transcripts. To elucidate transcriptional control of tubB2, we have mutated or removed sequences in the tubB2 promoter and examined the effect on transcription. The tubB2 promoter shares features with the promoters of other tubulin-encoding genes; these include a GC-rich region between the TATA box and the transcription initiation site and multiple copies of a 10-bp sequence motif that we call the tub box. The tubB2 gene contains seven tub box motifs. Changing the GC-rich region to an AT-rich region or removing three of the seven tub box motifs did not significantly affect transcription of the chimeric gene. However, removing four or five tub box motifs prevented increased transcription following deflagellation and diminished cell cycle-regulated transcription from the tubB2 promoter.

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