Mie Sasaki
Tokyo Laboratory
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Mie Sasaki.
Applied and Environmental Microbiology | 2003
Nobuyuki Horinouchi; Jun Ogawa; Takafumi Sakai; Takako Kawano; Seiichiro Matsumoto; Mie Sasaki; Yoichi Mikami; Sakayu Shimizu
ABSTRACT The gene encoding a deoxyriboaldolase (DERA) was cloned from the chromosomal DNA of Klebsiella pneumoniae B-4-4. This gene contains an open reading frame consisting of 780 nucleotides encoding 259 amino acid residues. The predicted amino acid sequence exhibited 94.6% homology with the sequence of DERA from Escherichia coli. The DERA of K. pneumoniae was expressed in recombinant E. coli cells, and the specific activity of the enzyme in the cell extract was as high as 2.5 U/mg, which was threefold higher than the specific activity in the K. pneumoniae cell extract. One of the E. coli transformants, 10B5/pTS8, which had a defect in alkaline phosphatase activity, was a good catalyst for 2-deoxyribose 5-phosphate (DR5P) synthesis from glyceraldehyde 3-phosphate and acetaldehyde. The E. coli cells produced DR5P from glucose and acetaldehyde in the presence of ATP. Under the optimal conditions, 100 mM DR5P was produced from 900 mM glucose, 200 mM acetaldehyde, and 100 mM ATP by the E. coli cells. The DR5P produced was further transformed to 2′-deoxyribonucleoside through coupling the enzymatic reactions of phosphopentomutase and nucleoside phosphorylase. These results indicated that production of 2′-deoxyribonucleoside from glucose, acetaldehyde, and a nucleobase is possible with the addition of a suitable energy source, such as ATP.
Bioscience, Biotechnology, and Biochemistry | 2003
Jun Ogawa; Kyota Saito; Takafumi Sakai; Nobuyuki Horinouchi; Takako Kawano; Seiichiro Matsumoto; Mie Sasaki; Yoichi Mikami; Sakayu Shimizu
2-Deoxyribose 5-phosphate was produced from acetaldehyde and dihydroxyacetone phosphate via D-glyceraldehyde 3-phosphate by Klebsiella pneumoniae B-4-4 through deoxyriboaldolase- and triosephosphate isomerase-catalyzing reactions. Under the optimum conditions, 98.7 mM 2-deoxyribose 5-phosphate was produced from 200 mM acetaldehyde and 117 mM dihydroxyacetone phosphate in 2 h with a molar yield of 84%. The 2-deoxyriobse 5-phosphate produced was directly transformed to 2′-deoxyribonucleoside by phosphopentomutase- and nucleoside phosphorylase-catalyzing reactions.
Bioscience, Biotechnology, and Biochemistry | 2006
Nobuyuki Horinouchi; Jun Ogawa; Takako Kawano; Takafumi Sakai; Kyota Saito; Seiichiro Matsumoto; Mie Sasaki; Yoichi Mikami; Sakayu Shimizu
2-Deoxyribose 5-phosphate production through coupling of the alcoholic fermentation system of baker’s yeast and deoxyriboaldolase-expressing Escherichia coli was investigated. In this process, baker’s yeast generates fructose 1,6-diphosphate from glucose and inorganic phosphate, and then the E. coli convert the fructose 1,6-diphosphate into 2-deoxyribose 5-phosphate via D-glyceraldehyde 3-phosphate. Under the optimized conditions with toluene-treated yeast cells, 356 mM (121 g/l) fructose 1,6-diphosphate was produced from 1,111 mM glucose and 750 mM potassium phosphate buffer (pH 6.4) with a catalytic amount of AMP, and the reaction supernatant containing the fructose 1,6-diphosphate was used directly as substrate for 2-deoxyribose 5-phosphate production with the E. coli cells. With 178 mM enzymatically prepared fructose 1,6-diphosphate and 400 mM acetaldehyde as substrates, 246 mM (52.6 g/l) 2-deoxyribose 5-phosphate was produced. The molar yield of 2-deoxyribose 5-phosphate as to glucose through the total two step reaction was 22.1%. The 2-deoxyribose 5-phosphate produced was converted to 2-deoxyribose with a molar yield of 85% through endogenous or exogenous phosphatase activity.
Microbial Cell Factories | 2012
Nobuyuki Horinouchi; Takafumi Sakai; Takako Kawano; Seiichiro Matsumoto; Mie Sasaki; Makoto Hibi; Jun Shima; Sakayu Shimizu; Jun Ogawa
BackgroundReproduction and sustainability are important for future society, and bioprocesses are one technology that can be used to realize these concepts. However, there is still limited variation in bioprocesses and there are several challenges, especially in the operation of energy-requiring bioprocesses. As an example of a microbial platform for an energy-requiring bioprocess, we established a process that efficiently and enzymatically synthesizes 2′-deoxyribonucleoside from glucose, acetaldehyde, and a nucleobase. This method consists of the coupling reactions of the reversible nucleoside degradation pathway and energy generation through the yeast glycolytic pathway.ResultsUsing E. coli that co-express deoxyriboaldolase and phosphopentomutase, a high amount of 2′-deoxyribonucleoside was produced with efficient energy transfer under phosphate-limiting reaction conditions. Keeping the nucleobase concentration low and the mixture at a low reaction temperature increased the yield of 2′-deoxyribonucleoside relative to the amount of added nucleobase, indicating that energy was efficiently generated from glucose via the yeast glycolytic pathway under these reaction conditions. Using a one-pot reaction in which small amounts of adenine, adenosine, and acetone-dried yeast were fed into the reaction, 75 mM of 2′-deoxyinosine, the deaminated product of 2′-deoxyadenosine, was produced from glucose (600 mM), acetaldehyde (250 mM), adenine (70 mM), and adenosine (20 mM) with a high yield relative to the total base moiety input (83%). Moreover, a variety of natural dNSs were further synthesized by introducing a base-exchange reaction into the process.ConclusionA critical common issue in energy-requiring bioprocess is fine control of phosphate concentration. We tried to resolve this problem, and provide the convenient recipe for establishment of energy-requiring bioprocesses. It is anticipated that the commercial demand for dNSs, which are primary metabolites that accumulate at very low levels in the metabolic pool, will grow. The development of an efficient production method for these compounds will have a great impact in both fields of applied microbiology and industry and will also serve as a good example of a microbial platform for energy-requiring bioprocesses.
Acute medicine and surgery | 2014
Tetsuhisa Kitamura; Taku Iwami; Takashi Kawamura; Chika Nishiyama; Tomohiko Sakai; Kayo Tanigawa-Sugihara; Mie Sasaki; Kentaro Kajino; Taro Irisawa; Sumito Hayashida; Tatsuya Nishiuchi; Atsushi Hiraide
This study investigated the association between the number of phone calls made to hospitals from ambulances requesting if they can accept prehospital emergency patients with cardiovascular events, and the prehospital transportation time.
Bioscience, Biotechnology, and Biochemistry | 2001
Michihiko Kataoka; Mie Sasaki; Aklani-Rose G.D. Hidalgo; Michiko Nakano; Sakayu Shimizu
Japanese Circulation Journal-english Edition | 2011
Mie Sasaki; Taku Iwami; Tetsuhisa Kitamura; Shinichi Nomoto; Chika Nishiyama; Tomohiko Sakai; Kayo Tanigawa; Kentaro Kajino; Taro Irisawa; Tatsuya Nishiuchi; Sumito Hayashida; Atsushi Hiraide; Takashi Kawamura
Circulation | 2011
Mie Sasaki; Taku Iwami; Tetsuhisa Kitamura; Shinichi Nomoto; Chika Nishiyama; Tomohiko Sakai; Kayo Tanigawa; Kentaro Kajino; Taro Irisawa; Tatsuya Nishiuchi; Sumito Hayashida; Atsushi Hiraide; Takashi Kawamura
Applied Microbiology and Biotechnology | 2006
Nobuyuki Horinouchi; Jun Ogawa; Takako Kawano; Takafumi Sakai; Kyota Saito; Seiichiro Matsumoto; Mie Sasaki; Yoichi Mikami; Sakayu Shimizu
Biotechnology Letters | 2006
Nobuyuki Horinouchi; Jun Ogawa; Takako Kawano; Takafumi Sakai; Kyota Saito; Seiichiro Matsumoto; Mie Sasaki; Yoichi Mikami; Sakayu Shimizu