Influence of Cell Size and DNA Content on Growth Rate and Photosystem II Function in Cryptic Species of Ditylum brightwellii

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

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DNA-content of soil bacteria of different cell size

Soil Biology and Biochemistry ◽

10.1016/0038-0717(89)90172-7 ◽

1989 ◽

Vol 21 (6) ◽

pp. 789-793 ◽

Cited By ~ 56

Author(s):

L BAKKEN ◽

R OLSEN

Keyword(s):

Cell Size ◽

Dna Content ◽

Soil Bacteria

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Analysis of cell size and DNA content in exponentially growing and stationary-phase batch cultures of Escherichia coli.

Journal of Bacteriology ◽

10.1128/jb.177.23.6791-6797.1995 ◽

1995 ◽

Vol 177 (23) ◽

pp. 6791-6797 ◽

Cited By ~ 186

Author(s):

T Akerlund ◽

K Nordström ◽

R Bernander

Keyword(s):

Escherichia Coli ◽

Stationary Phase ◽

Cell Size ◽

Dna Content ◽

Batch Cultures

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

Applied and Environmental Microbiology ◽

10.1128/aem.02441-20 ◽

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.

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Potential Maximum Quantum Yield of Photosystem II Reflects the Growth Rate of Chattonella marina in Field Bloom Samples

Journal of the Faculty of Agriculture, Kyushu University ◽

10.5109/1685889 ◽

2016 ◽

Vol 61 (2) ◽

pp. 331-335 ◽

Cited By ~ 1

Author(s):

Xuchun Qiu ◽

Kouki Mukai ◽

Yohei Shimasaki ◽

Michito Tsuyama ◽

Tadashi Matsubara ◽

...

Keyword(s):

Growth Rate ◽

Quantum Yield ◽

Photosystem Ii ◽

Maximum Quantum Yield ◽

Chattonella Marina ◽

Potential Maximum

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Covariation of metabolic rates and cell size in coccolithophores

Biogeosciences ◽

10.5194/bg-12-4665-2015 ◽

2015 ◽

Vol 12 (15) ◽

pp. 4665-4692 ◽

Cited By ~ 15

Author(s):

G. Aloisi

Keyword(s):

Growth Rate ◽

Environmental Change ◽

Cell Size ◽

Environmental Conditions ◽

Laboratory Experiments ◽

Opposite Effect ◽

Cell Structure ◽

Metabolic Rates ◽

The Future ◽

Phytoplankton Group

Abstract. Coccolithophores are sensitive recorders of environmental change. The size of their coccosphere varies in the ocean along gradients of environmental conditions and provides a key for understanding the fate of this important phytoplankton group in the future ocean. But interpreting field changes in coccosphere size in terms of laboratory observations is hard, mainly because the marine signal reflects the response of multiple morphotypes to changes in a combination of environmental variables. In this paper I examine the large corpus of published laboratory experiments with coccolithophores looking for relations between environmental conditions, metabolic rates and cell size (a proxy for coccosphere size). I show that growth, photosynthesis and, to a lesser extent, calcification covary with cell size when pCO2, irradiance, temperature, nitrate, phosphate and iron conditions change. With the exception of phosphate and temperature, a change from limiting to non-limiting conditions always results in an increase in cell size. An increase in phosphate or temperature (below the optimum temperature for growth) produces the opposite effect. The magnitude of the coccosphere-size changes observed in the laboratory is comparable to that observed in the ocean. If the biological reasons behind the environment–metabolism–size link are understood, it will be possible to use coccosphere-size changes in the modern ocean and in marine sediments to investigate the fate of coccolithophores in the future ocean. This reasoning can be extended to the size of coccoliths if, as recent experiments are starting to show, coccolith size reacts to environmental change proportionally to coccosphere size. The coccolithophore database is strongly biased in favour of experiments with the coccolithophore Emiliania huxleyi (E. huxleyi; 82 % of database entries), and more experiments with other species are needed to understand whether these observations can be extended to coccolithophores in general. I introduce a simple model that simulates the growth rate and the size of cells forced by nitrate and phosphate concentrations. By considering a simple rule that allocates the energy flow from nutrient acquisition to cell structure (biomass) and cell maturity (biological complexity, eventually leading to cell division), the model is able to reproduce the covariation of growth rate and cell size observed in laboratory experiments with E. huxleyi when these nutrients become limiting. These results support ongoing efforts to interpret coccosphere and coccolith size measurements in the context of climate change.

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