The cell cycle of symbiotic Chlorella. IV. DNA content of algae slowly increases during host starvation of green hydra

1986 ◽  
Vol 85 (1) ◽  
pp. 73-84
Author(s):  
P.J. McAuley ◽  
L. Muscatine
Keyword(s):  
Cell Size ◽  
Dna Content ◽  
Algal Cell ◽  
S Phase ◽  
Symbiotic Algae ◽  
Daughter Cells ◽  
Green Hydra ◽  
Significant Difference ◽  
Preceding Period ◽  
Chlorella Algae

The distribution of DNA content of symbiotic Chlorella algae freshly isolated from green hydra was compared with that of cultured Chlorella of the NC64A strain, using flow cytometry. In nonlogarithmic cultures of NC64A most cells had accumulated in G1 phase, while in logarithmic cultures a peak containing cells in S phase and mitosis could be distinguished from the larger G1 peak. However, symbiotic algae showed a single broad peak in which there was no clear distinction between G1 and S phase/mitosis. When hydra were starved for a prolonged period, inhibiting host cell and algal division, the DNA content of the symbiotic algae slowly increased, and the number of daughter cells produced after a single feeding increased with the length of the preceding period of starvation. This suggests that symbiotic algae are able to cycle slowly through S phase, but unless the host is fed they cannot traverse into mitosis and complete the cell division cycle. No significant difference in cell size was found between algae producing either four or eight daughter cells after 1-day- or 22-day-starved hydra were fed, suggesting that algal cell size did not determine the number of daughter cells produced. Instead, this may be dependent upon the length of time the cell had spent in S phase prior to receiving the, as yet unknown, stimulus to enter into mitosis.

The cell cycle of symbiotic Chlorella. III. Numbers of algae in green hydra digestive cells are regulated at digestive cell division

1986 ◽  
Vol 85 (1) ◽  
pp. 63-71
Author(s):  
P.J. McAuley
Keyword(s):  
Cell Division ◽  
Host Cell ◽  
Algal Cell ◽  
Host Cells ◽  
Digestive Cell ◽  
Digestive Cells ◽  
Daughter Cells ◽  
Green Hydra ◽  
Mother And Daughter ◽  
Chlorella Algae

Regression analysis of the relationship between the size of interphase and mitotic digestive cells of green hydra, and the numbers and total volume of the symbiotic Chlorella algae they contain showed a partial correlation only, suggesting that numbers of algae per cell are not regulated by limiting them to a specific proportion of the host cell, and that the variation observed in numbers of algae per cell is not due to variation in host cell size. After hydra were fed, which stimulates algae and digestive cells to divide at the same time, numbers of algae per cell were higher in prophase than in interphase cells, and numbers increased as mitosis proceeded. In excised regenerating peduncles algae divide before digestive cells, and at the onset of digestive cell division mitotic cells were found to contain almost twice the number of algae as before excision. Thus, almost all of the algal cell division necessary to maintain a constant population size was associated with digestive cell division. Analysis of variance in numbers of algae in telophase mother and daughter cells suggested that the proportion of algae dividing as a result of host cell mitosis was greater in digestive cells with few algae than in those with many algae. The fact that the mechanism controlling the proportion of algae dividing in host cells is expressed at host cell division and is manifested in the daughter cells may contribute to wide variation in numbers of algae per cell.

scholarly journals The Complex Cell Cycle of the Dinoflagellate Protoctist Crypthecodinium Cohnii as Studied In Vivo and by Cytofluorimetry

1991 ◽  
Vol 100 (3) ◽  
pp. 675-682 ◽  
Author(s):  
YVONNE BHAUD ◽  
JEAN-MARIE SALMON ◽  
MARIE-ODILE SOYER-GOBILLARD
Keyword(s):  
Cell Cycle ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
S Phase ◽  
Vegetative Cells ◽  
Crypthecodinium Cohnii ◽  
Daughter Cells ◽  
The Times

The complete cell cycle of the dinoflagellate Crypthecodinium cohnii Biecheler 1938 was observed in vivo in a synchronized heterogeneous population, after DAPI staining of DNA. In a given population, the relative nuclear DNA content in each class of cell was measured using a new numerical image-analysis method that takes into account the total fluorescence intensity (FI), area (A) and shape factor (SF). The visible degree of synchronization of the population was determined from the number of cells with a nuclear content of 1C DNA at ‘synchronization’, time 0. One method of synchronization (method 1), based on the adhesiveness of the cysts, gave no better than 50% synchronization of the population; method 2, based on swimming cells released from cysts cultured on solid medium, gave 73% of cells with the same nuclear DNA content. A scatter plot of data for FI versus A in the first few hours after time 0 showed that the actual degree of synchronization of the population was lower. The length of the C. cohnii cell cycle determined in vivo by light microscopy was 10, 16 or 24 h for vegetative cells giving two, four or eight daughter cells, respectively. Histograms based on the FI measurements showed that in an initially synchronized population observed for 20 h, the times for the first cell cycle were: G1 phase, 6 h; S phase, 1 h 30 min; G2+M, 1h 30 min, with the release of vegetative cells occurring 1 or 2h after the end of cytokinesis. The times for the second cell cycle were G1+S, 3h; G2+M, 2h. FI and A taken together, suggested that the S phase is clearly restricted, as in higher eukaryotes. A and SF, taken together, showed that the large nuclear areas were always in cysts with two or four daughter cells. FI and SF, taken together, showed that the second S phase always occurred after completion of the first nuclear division. Our data concerning the course of the cell cycle in C. cohnii are compared with those from earlier studies, and the control of the number of daughter cells is discussed; this does not depend on the ploidy of the mother cell.

scholarly journals Cell size controlled in plants using DNA content as an internal scale

Science ◽  
2021 ◽  
Vol 372 (6547) ◽  
pp. 1176-1181
Author(s):  
Marco D’Ario ◽  
Rafael Tavares ◽  
Katharina Schiessl ◽  
Bénédicte Desvoyes ◽  
Crisanto Gutierrez ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Cell Size ◽  
Dna Content ◽  
Growth Period ◽  
Mitotic Chromosomes ◽  
Daughter Cells ◽  
Asymmetric Divisions ◽  
A Cell ◽  
Size Variability ◽  
Cell Niche

How eukaryotic cells assess and maintain sizes specific for their species and cell type remains unclear. We show that in the Arabidopsis shoot stem cell niche, cell size variability caused by asymmetric divisions is corrected by adjusting the growth period before DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to DNA synthesis and associates with mitotic chromosomes. The F BOX-LIKE 17 (FBL17) protein removes excess KRP4. Consequently, daughter cells are born with comparable amounts of KRP4. Inhibitor dilution models predicted that KRP4 inherited through chromatin would robustly regulate size, whereas inheritance of excess free KRP4 would disrupt size homeostasis, as confirmed by mutant analyses. We propose that a cell cycle regulator, stabilized by association with mitotic chromosomes, reads DNA content as a cell size–independent scale.

Stress tolerance alteration in the freshwater cnidarian green hydra (Hydra viridissima) via symbiotic algae mutagenesis

Symbiosis ◽  
2020 ◽  
Vol 82 (3) ◽  
pp. 189-199
Author(s):  
Siao Ye ◽  
Meenakshi Bhattacharjee ◽  
Evan Siemann
Keyword(s):  
Stress Tolerance ◽  
Symbiotic Algae ◽  
Green Hydra

Development of matured hiPSCs-derived 3D cardiac tissue using ERR gamma agonist and mechanical stress and application for Hypertrophic Cardiomyopathy (HCM) model

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Fujiwara ◽  
K Deguchi ◽  
Y Naka ◽  
M Sasaki ◽  
T Nishimoto ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Hypertrophic Cardiomyopathy ◽  
Mechanical Stress ◽  
Cell Size ◽  
Dna Content ◽  
Disease Model ◽  
Heart Tissue ◽  
Funding Source ◽  
Mitochondrial Dna Content ◽  
Mechanical Stretching

Abstract Introduction Tissue engineering using human induced pluripotent stem cells-derived cardiomyocytes (hiPSCs-CMs) is one of the potential tools to replicate human heart in vitro. Although there are many publications on 3 dimensional (3D) heart tissues (1), these tissues show fetal like phenotypes. For that reason, several maturation methods such as electrical stimulation and mechanical stress have been investigated (2, 3). However, these methods have been inadequate in differentiating fetal like phenotype tissue from adult tissues. Previously, we identified a novel compound, T112, which induced hiPSCs-CMs maturation from approximately 9,000 compounds using Troponin I1-EmGFP and Troponin I3-mCherry double reporter hiPSCs-CMs. This compound enhanced morphological and metabolic maturation of hiPSCs-CMs via estrogen-rerated receptor gamma activation Purpose We hypothesized that our novel compound, T112, in combination with mechanical stress could result in further maturation of 3D heart tissue. Therefore, our specific aim is to develop a novel maturation method applicable to genetic disease model of HCM using 3D heart tissue combined with T112. Methods We constructed 3D heart tissue mixed with fibroblast and double reporter hiPSCs-CMs by the hydrogel methods using Flex cell system®. We added T112 with or without mechanical stretching to 3D tissue from 7 to 15 days after 3D heart tissue was constructed. Then we measured maturation related phenotype such as sarcomere gene expression, mitochondrial DNA content and cell size. Results Similar to hiPSCs-CM, the addition of T112 to the constructed 3D heart tissue significantly increased TNNI3 mRNA compared to that of DMSO. Furthermore, T112 treated 3D heart tissue showed increased cell size and oblong shape. Next, in order to promote more maturation of 3D heart tissue, we performed mechanical stretching with the addition of T112. The combination of T112 with mechanical stretching showed higher expression of mCherry, a reporter protein for TNNI3 expression, and higher isotropy of sarcomere alignment in 3D heart tissue than that with the static condition. Furthermore, 3D heart tissue in the treatment of T112 with or without mechanical stretching showed higher mitochondrial DNA content compared to the respective DMSO controls. Interestingly, we applied this combination method to hiPSCs carrying MYH7 R719Q mutation which is known to cause hypertrophic cardiomyopathy, and the 3D heart tissue composed of cardiomyocytes derived from mutant iPSCs demonstrated increased sarcomere disarray compared to isogenic wild-type 3D heart tissue. Conclusion These results suggest that the combination of T112 and mechanical stretching promotes metabolic and structural maturation of 3D heart tissue and would be useful for creating a HCM disease model. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): T-CiRA project, Takeda Pharmaceutical Company Limited

DNA-content of soil bacteria of different cell size

1989 ◽  
Vol 21 (6) ◽  
pp. 789-793 ◽  
Author(s):  
L BAKKEN ◽  
R OLSEN
Keyword(s):  
Cell Size ◽  
Dna Content ◽  
Soil Bacteria

scholarly journals Rate of replication of the murine immunoglobulin heavy-chain locus: evidence that the region is part of a single replicon.

1987 ◽  
Vol 7 (1) ◽  
pp. 450-457 ◽  
Author(s):  
E H Brown ◽  
M A Iqbal ◽  
S Stuart ◽  
K S Hatton ◽  
J Valinsky ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Line ◽  
Gene Cluster ◽  
Cell Lines ◽  
Heavy Chain ◽  
Dna Content ◽  
Immunoglobulin Heavy Chain ◽  
S Phase ◽  
C Value ◽  
Murine Erythroleukemia

We measured the temporal order of replication of EcoRI segments from the murine immunoglobulin heavy-chain constant region (IgCH) gene cluster, including the joining (J) and diversity (D) loci and encompassing approximately 300 kilobases. The relative concentrations of EcoRI segments in bromouracil-labeled DNA that replicated during selected intervals of the S phase in Friend virus-transformed murine erythroleukemia (MEL) cells were measured. From these results, we calculated the nuclear DNA content (C value; the haploid DNA content of a cell in the G1 phase of the cell cycle) at the time each segment replicated during the S phase. We observed that IgCH genes replicate in the following order: alpha, epsilon, gamma 2a, gamma 2b, gamma 1, gamma 3, delta, and mu, followed by the J and D segments. The C value at which each segment replicates increased as a linear function of its distance from C alpha. The average rate of DNA replication in the IgCH gene cluster was determined from these data to be 1.7 to 1.9 kilobases/min, similar to the rate measured for mammalian replicons by autoradiography and electron microscopy (for a review, see H. J. Edenberg and J. A. Huberman, Annu. Rev. Genet. 9:245-284, 1975, and R. G. Martin, Adv. Cancer Res. 34:1-55, 1981). Similar results were obtained with other murine non-B cell lines, including a fibroblast cell line (L60T) and a hepatoma cell line (Hepa 1.6). In contrast, we observed that IgCh segments in a B-cell plasmacytoma (MPC11) and two Abelson murine leukemia virus-transformed pre-B cell lines (22D6 and 300-19O) replicated as early as (300-19P) or earlier than (MPC11 and 22D6) C alpha in MEL cells. Unlike MEL cells, however, all of the IgCH segments in a given B cell line replicated at very similar times during the S phase, so that a temporal directionality in the replication of the IgCH gene cluster was not apparent from these data. These results provide evidence that in murine non-B cells the IgCH, J, and D loci are part of a single replicon.

scholarly journals The Ethanologenic Bacterium Zymomonas mobilis Divides Asymmetrically and Exhibits Heterogeneity in DNA Content

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Katsuya Fuchino ◽  
Helena Chan ◽  
Ling Chin Hwang ◽  
Per Bruheim
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Dna Content ◽  
Bacterial Cell ◽  
Zymomonas Mobilis ◽  
Biofuel Production ◽  
Public Attention ◽  
Content Type ◽  
Cell Organization

ABSTRACT The alphaproteobacterium Zymomonas mobilis exhibits extreme ethanologenic physiology, making this species a promising biofuel producer. Numerous studies have investigated its biology relevant to industrial applications and mostly at the population level. However, the organization of single cells in this industrially important polyploid species has been largely uncharacterized. In the present study, we characterized basic cellular behavior of Z. mobilis strain Zm6 under anaerobic conditions at the single-cell level. We observed that growing Z. mobilis cells often divided at a nonmidcell position, which contributed to variant cell size at birth. However, the cell size variance was regulated by a modulation of cell cycle span, mediated by a correlation of bacterial tubulin homologue FtsZ ring accumulation with cell growth. The Z. mobilis culture also exhibited heterogeneous cellular DNA content among individual cells, which might have been caused by asynchronous replication of chromosome that was not coordinated with cell growth. Furthermore, slightly angled divisions might have resulted in temporary curvatures of attached Z. mobilis cells. Overall, the present study uncovers a novel bacterial cell organization in Z. mobilis. IMPORTANCE With increasing environmental concerns about the use of fossil fuels, development of a sustainable biofuel production platform has been attracting significant public attention. Ethanologenic Z. mobilis species are endowed with an efficient ethanol fermentation capacity that surpasses, in several respects, that of baker’s yeast (Saccharomyces cerevisiae), the most-used microorganism for ethanol production. For development of a Z. mobilis culture-based biorefinery, an investigation of its uncharacterized cell biology is important, because bacterial cellular organization and metabolism are closely associated with each other in a single cell compartment. In addition, the current work demonstrates that the polyploid bacterium Z. mobilis exhibits a distinctive mode of bacterial cell organization, likely reflecting its unique metabolism that does not prioritize incorporation of nutrients for cell growth. Thus, another significant result of this work is to advance our general understanding in the diversity of bacterial cell architecture.

The implication of DNA content and S-phase fraction in oral carcinomas with and without metastasis

1995 ◽  
Vol 24 (6) ◽  
pp. 427-432 ◽  
Author(s):  
Jalal Uddin Mahmood ◽  
Katsuya Suzuki ◽  
Tsutomu Nomura ◽  
Susumu Shingaki ◽  
Tamio Nakajima
Keyword(s):  
Dna Content ◽  
S Phase ◽  
Phase Fraction
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