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Universal Statistics for Chemical Abundances in a Reproducing Cell
Chikara Furusawa,Kunihiko Kaneko 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.1I
Two universal statistical laws in the reaction dynamics of reproducing cells are reported that appear as a result of consistency between molecular replication and cell reproductions as a whole. First, the overall abundances of chemicals in a cell, when ordered by magnitude and plotted as a function of their rank, obey a power law with an exponent close to .1. Second, the distribution of abundances for each chemical species measured over many cells obeys a log-normal distribution. The ubiquity of these two laws is confirmed theoretically. By means of a model with a catalytic reaction network, these two laws hold universally whenever a cell exhibits efficient self-reproduction. The origin of the laws is explained theoretically by noting the cascade structure of catalytic reactions. We briefly mention experimental support for the laws by using data from gene expression analyses.
Nagahisa, Keisuke,Nakajima, Toshiharu,Yoshikawa, Katsunori,Hirasawa, Takashi,Katakura, Yoshio,Furusawa, Chikara,Shioya, Suteaki,Shimizu, Hiroshi The Korean Society for Biotechnology and Bioengine 2005 Biotechnology and Bioprocess Engineering Vol.10 No.5
The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8. by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carton dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0. consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.
Hiroshi Shimizu,Keisuke Nagahisa,Toshiharu Nakajima,Katsunori Yoshikawa,Takashi Hirasawa,Yoshio Katakura,Chikara Furusawa,Suteaki Shioya 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.5
The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8, by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carbon dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0, consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.