scholarly journals Effect of morphactin (chlorfluorenol IT 3456) on the mitotic activity and cell growth in roots of Pisum sativum L.

2014 ◽  
Vol 51 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Barbara Gabara
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Growth ◽  
Thymidine Incorporation ◽  
S Phase ◽  
Cycle Duration ◽  
Nuclear Surface ◽  
Pisum Sativum L ◽  
Cell Cycle Duration ◽  
The Mean

Morphactin in a concentration of 100 ppm does not retard pea root growth, however, it reduced the frequency of cell division and shifted the main wave of mitoses in the 24 h period from 1 to 2 mm of root segment. The mean cell cycle duration is prolonged from 14 h in the control to 22 h in morphactin-treated roots. In the presence of morphactin the decrease of <sup>3</sup>H-thymidine incorporation and diminution of labelling index is accompanied by reduction of the nuclear surface area. The described changes are not accompanied by shortening of cell length. The results obtained suggest that morphactin disturbs the mechanisms regulating the initiation of S phase and its regular course. Moreover, it inhibits the endomitotic replication of DNA.

scholarly journals Effects of cell cycle variability on lineage and population measurements of mRNA abundance

2020 ◽  
Author(s):  
Ruben Perez-Carrasco ◽  
Casper Beentjes ◽  
Ramon Grima
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Negative Binomial ◽  
Eukaryotic Cell ◽  
Cycle Duration ◽  
Cell Cycle Duration ◽  
Monotonically Decreasing Function ◽  
Binomial Mixture ◽  
A Cell ◽  
The Mean

AbstractMany models of gene expression do not explicitly incorporate a cell cycle description. Here we derive a theory describing how mRNA fluctuations for constitutive and bursty gene expression are influenced by stochasticity in the duration of the cell cycle and the timing of DNA replication. Analytical expressions for the moments show that omitting cell cycle duration introduces an error in the predicted mean number of mRNAs that is a monotonically decreasing function of η, which is proportional to the ratio of the mean cell cycle duration and the mRNA lifetime. By contrast, the error in the variance of the mRNA distribution is highest for intermediate values of η consistent with genome-wide measurements in many organisms. Using eukaryotic cell data, we estimate the errors in the mean and variance to be at most 3% and 25%, respectively. Furthermore, we derive an accurate negative binomial mixture approximation to the mRNA distribution. This indicates that stochasticity in the cell cycle can introduce fluctuations in mRNA numbers that are similar to the effect of bursty transcription. Finally, we show that for real experimental data, disregarding cell cycle stochasticity can introduce errors in the inference of transcription rates larger than 10%.

scholarly journals Effects of cell cycle variability on lineage and population measurements of messenger RNA abundance

2020 ◽  
Vol 17 (168) ◽  
pp. 20200360 ◽  
Author(s):  
Ruben Perez-Carrasco ◽  
Casper Beentjes ◽  
Ramon Grima
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Messenger Rna ◽  
Negative Binomial ◽  
Eukaryotic Cell ◽  
Cycle Duration ◽  
Cell Cycle Duration ◽  
Monotonically Decreasing Function ◽  
Binomial Mixture ◽  
The Mean

Many models of gene expression do not explicitly incorporate a cell cycle description. Here, we derive a theory describing how messenger RNA (mRNA) fluctuations for constitutive and bursty gene expression are influenced by stochasticity in the duration of the cell cycle and the timing of DNA replication. Analytical expressions for the moments show that omitting cell cycle duration introduces an error in the predicted mean number of mRNAs that is a monotonically decreasing function of η , which is proportional to the ratio of the mean cell cycle duration and the mRNA lifetime. By contrast, the error in the variance of the mRNA distribution is highest for intermediate values of η consistent with genome-wide measurements in many organisms. Using eukaryotic cell data, we estimate the errors in the mean and variance to be at most 3% and 25%, respectively. Furthermore, we derive an accurate negative binomial mixture approximation to the mRNA distribution. This indicates that stochasticity in the cell cycle can introduce fluctuations in mRNA numbers that are similar to the effect of bursty transcription. Finally, we show that for real experimental data, disregarding cell cycle stochasticity can introduce errors in the inference of transcription rates larger than 10%.

scholarly journals A Short-Term Advantage for Syngamy in the Origin of Eukaryotic Sex: Effects of Cell Fusion on Cell Cycle Duration and Other Effects Related to the Duration of the Cell Cycle—Relationship between Cell Growth Curve and the Optimal Size of the Species, and Circadian Cell Cycle in Photosynthetic Unicellular Organisms

2012 ◽  
Vol 2012 ◽  
pp. 1-25 ◽  
Author(s):  
J. M. Mancebo Quintana ◽  
S. Mancebo Quintana
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cell Fusion ◽  
Growth Curve ◽  
Evolutionary Biology ◽  
Optimal Size ◽  
Cycle Duration ◽  
Unicellular Algae ◽  
Cell Cycle Duration ◽  
Unicellular Organisms

The origin of sex is becoming a vexatious issue for Evolutionary Biology. Numerous hypotheses have been proposed, based on the genetic effects of sex, on trophic effects or on the formation of cysts and syncytia. Our approach addresses the change in cell cycle duration which would cause cell fusion. Several results are obtained through graphical and mathematical analysis and computer simulations. (1) In poor environments, cell fusion would be an advantageous strategy, as fusion between cells of different size shortens the cycle of the smaller cell (relative to the asexual cycle), and the majority of mergers would occur between cells of different sizes. (2) The easiest-to-evolve regulation of cell proliferation (sexual/asexual) would be by modifying the checkpoints of the cell cycle. (3) A regulation of this kind would have required the existence of the G2 phase, and sex could thus be the cause of the appearance of this phase. Regarding cell cycle, (4) the exponential curve is the only cell growth curve that has no effect on the optimal cell size in unicellular species; (5) the existence of a plateau with no growth at the end of the cell cycle explains the circadian cell cycle observed in unicellular algae.

scholarly journals Size control in mammalian cells involves modulation of both growth rate and cell cycle duration

2017 ◽  
Author(s):  
Clotilde Cadart ◽  
Sylvain Monnier ◽  
Jacopo Grilli ◽  
Rafaele Attia ◽  
Emmanuel Terriac ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Growth Rate ◽  
Cell Division ◽  
Cell Growth ◽  
Single Cell ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Size Control ◽  
Cycle Duration ◽  
Mathematical Framework

SummaryDespite decades of research, it remains unclear how mammalian cell growth varies with cell size and across the cell division cycle to maintain size control. Answers have been limited by the difficulty of directly measuring growth at the single cell level. Here we report direct measurement of single cell volumes over complete cell division cycles. The volume added across the cell cycle was independent of cell birth size, a size homeostasis behavior called “adder”. Single-cell growth curves revealed that the homeostatic behavior relied on adaptation of G1 duration as well as growth rate modulations. We developed a general mathematical framework that characterizes size homeostasis behaviors. Applying it on datasets ranging from bacteria to mammalian cells revealed that a near-adder is the most common type of size control, but only mammalian cells achieve it using modulation of both cell growth rate and cell-cycle progression.

scholarly journals The Effect of Dia2 Protein Deficiency on the Cell Cycle, Cell Size, and Recruitment of Ctf4 Protein in Saccharomyces cerevisiae

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 97
Author(s):  
Aneliya Ivanova ◽  
Aleksandar Atemin ◽  
Sonya Uzunova ◽  
Georgi Danovski ◽  
Radoslav Aleksandrov ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Cell Size ◽  
Ubiquitin Ligase ◽  
Driving Forces ◽  
S Phase ◽  
Cycle Duration ◽  
Cell Cycles ◽  
Cell Cycle Duration

Cells have evolved elaborate mechanisms to regulate DNA replication machinery and cell cycles in response to DNA damage and replication stress in order to prevent genomic instability and cancer. The E3 ubiquitin ligase SCFDia2 in S. cerevisiae is involved in the DNA replication and DNA damage stress response, but its effect on cell growth is still unclear. Here, we demonstrate that the absence of Dia2 prolongs the cell cycle by extending both S- and G2/M-phases while, at the same time, activating the S-phase checkpoint. In these conditions, Ctf4—an essential DNA replication protein and substrate of Dia2—prolongs its binding to the chromatin during the extended S- and G2/M-phases. Notably, the prolonged cell cycle when Dia2 is absent is accompanied by a marked increase in cell size. We found that while both DNA replication inhibition and an absence of Dia2 exerts effects on cell cycle duration and cell size, Dia2 deficiency leads to a much more profound increase in cell size and a substantially lesser effect on cell cycle duration compared to DNA replication inhibition. Our results suggest that the increased cell size in dia2∆ involves a complex mechanism in which the prolonged cell cycle is one of the driving forces.

Genome in toto

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 361-362 ◽  
Author(s):  
Alexander E Vinogradov
Keyword(s):  
Cell Cycle ◽  
Genome Evolution ◽  
Genome Size ◽  
Cycle Duration ◽  
Noncoding Dna ◽  
Cell Cycle Duration ◽  
The Relationship

At a certain temperature, which is a compromise for temperatures at which the species are adapted, the relationship between genome size and cell cycle duration during synchronous cleavage divisions can be very strong (r = 1.00, P < 0.01) in four closely related frogs, suggesting a functional dependence.Key words: genome size, genome evolution, genome cytoecology, noncoding DNA, cell cycle duration.

scholarly journals A 20-bp insertion/deletion (indel) polymorphism within the <i>CDC25A</i> gene and its associations with growth traits in goat

2019 ◽  
Vol 62 (1) ◽  
pp. 353-360 ◽  
Author(s):  
Wenbo Cui ◽  
Nuan Liu ◽  
Xuelian Zhang ◽  
Yanghai Zhang ◽  
Lei Qu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Growth And Development ◽  
Marker Assisted Selection ◽  
Growth Traits ◽  
S Phase ◽  
Cashmere Goat ◽  
Indel Polymorphism ◽  
Candidate Marker ◽  
Essential Function

Abstract. Cell division cycle 25A (CDC25A), a member of the CDC25 family of phosphatases, is required for progression from G1 to the S phase of the cell cycle. CDC25A provides an essential function during early embryonic development in mice, suggesting that it plays an important role in growth and development. In this study, we used mathematical expectation (ME) methods to identify a 20-bp insertion/deletion (indel) polymorphism of CDC25A gene in Shaanbei White Cashmere (SBWC) goats. We also investigated the association between this 20-bp indel and growth-related traits in SBWC goats. Association results showed that the indel was related to growth traits (height at hip cross, cannon circumference, and cannon circumference index) in SBWC goats. The height at hip cross of individuals with insertion/insertion (II) genotype was higher than those with insertion/deletion (ID) genotype (P=0.02); on the contrary, the cannon circumference and cannon circumference index of individuals with ID genotype were superior when compared with those with II genotype (P=0.017 and P=0.009). These findings suggest that the 20-bp indel in the CDC25A gene significantly affects growth-related traits, and could be utilized as a candidate marker for marker-assisted selection (MAS) in the cashmere goat industry.

scholarly journals Lateral Root Priming Synergystically Arises from Root Growth and Auxin Transport Dynamics

2018 ◽  
Author(s):  
Thea van den Berg ◽  
Kirsten H. ten Tusscher
Keyword(s):  
Cell Cycle ◽  
Root Growth ◽  
Lateral Root ◽  
Root Formation ◽  
Growth Dynamics ◽  
Root Tip ◽  
Cycle Duration ◽  
Elongation Zone ◽  
Lateral Root Formation ◽  
Cell Cycle Duration

AbstractThe root system is a major determinant of plant fitness. Its capacity to supply the plant with sufficient water and nutrients strongly depends on root system architecture, which arises from the repeated branching off of lateral roots. A critical first step in lateral root formation is priming, which prepatterns sites competent of forming a lateral root. Priming is characterized by temporal oscillations in auxin, auxin signalling and gene expression in the root meristem, which through growth become transformed into a spatially repetitive pattern of competent sites. Previous studies have demonstrated the importance of auxin synthesis, transport and perception for the amplitude of these oscillations and their chances of producing an actual competent site. Additionally, repeated lateral root cap apoptosis was demonstrated to be strongly correlated with repetitive lateral root priming. Intriguingly, no single mutation has been identified that fully abolishes lateral root formation, and thusfar the mechanism underlying oscillations has remained unknown. In this study, we investigated the impact of auxin reflux loop properties combined with root growth dynamics on priming, using a computational approach. To this end we developed a novel multi-scale root model incorporating a realistic root tip architecture and reflux loop properties as well as root growth dynamics. Excitingly, in this model, repetitive auxin elevations automatically emerge. First, we show that root tip architecture and reflux loop properties result in an auxin loading zone at the start of the elongation zone, with preferential auxin loading in narrow vasculature cells. Second, we demonstrate how meristematic root growth dynamics causes regular alternations in the sizes of cells arriving at the elongation zone, which subsequently become amplified during cell expansion. These cell size differences translate into differences in cellular auxin loading potential. Combined, these properties result in temporal and spatial fluctuations in auxin levels in vasculature and pericycle cells. Our model predicts that temporal priming frequency predominantly depends on cell cycle duration, while cell cycle duration together with meristem size control lateral root spacing.

scholarly journals Cell growth dilutes the cell cycle inhibitor Rb to trigger cell division

2018 ◽  
Author(s):  
Evgeny Zatulovskiy ◽  
Daniel F. Berenson ◽  
Benjamin R. Topacio ◽  
Jan M. Skotheim
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Growth ◽  
Cell Size ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Inverse Correlation ◽  
Cell Types ◽  
Similar Amount ◽  
Cell Cycle Inhibitor

Cell size is fundamental to function in different cell types across the human body because it sets the scale of organelle structures, biosynthesis, and surface transport1,2. Tiny erythrocytes squeeze through capillaries to transport oxygen, while the million-fold larger oocyte divides without growth to form the ~100 cell pre-implantation embryo. Despite the vast size range across cell types, cells of a given type are typically uniform in size likely because cells are able to accurately couple cell growth to division3–6. While some genes whose disruption in mammalian cells affects cell size have been identified, the molecular mechanisms through which cell growth drives cell division have remained elusive7–12. Here, we show that cell growth acts to dilute the cell cycle inhibitor Rb to drive cell cycle progression from G1 to S phase in human cells. In contrast, other G1/S regulators remained at nearly constant concentration. Rb is a stable protein that is synthesized during S and G2 phases in an amount that is independent of cell size. Equal partitioning to daughter cells of chromatin bound Rb then ensures that all cells at birth inherit a similar amount of Rb protein. RB overexpression increased cell size in tissue culture and a mouse cancer model, while RB deletion decreased cell size and removed the inverse correlation between cell size at birth and the duration of G1 phase. Thus, Rb-dilution by cell growth in G1 provides a long-sought cell autonomous molecular mechanism for cell size homeostasis.

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