Tajima Y.,Ajinomoto Co. |
Kaida K.,Ajinomoto Co. |
Hayakawa A.,Ajinomoto Co. |
Fukui K.,Ajinomoto Co. |
And 6 more authors.
Applied Microbiology and Biotechnology | Year: 2014
Succinate is a core biochemical building block; optimizing succinate production from biomass by microbial fermentation is a focus of basic and applied biotechnology research. Lowering pH in anaerobic succinate fermentation culture is a cost-effective and environmentally friendly approach to reducing the use of sub-raw materials such as alkali, which are needed for neutralization. To evaluate the potential of bacteria-based succinate fermentation under weak acidic (pH <6.2) and anaerobic conditions, we characterized the anaerobic metabolism of Enterobacter aerogenes AJ110637, which rapidly assimilates glucose at pH 5.0. Based on the profile of anaerobic products, we constructed single-gene knockout mutants to eliminate the main anaerobic metabolic pathways involved in NADH re-oxidation. These single-gene knockout studies showed that the ethanol synthesis pathway serves as the dominant NADH re-oxidation pathway in this organism. To generate a metabolically engineered strain for succinate production, we eliminated ethanol formation and introduced a heterogeneous carboxylation enzyme, yielding E. aerogenes strain ΔadhE/PCK. The strain produced succinate from glucose with a 60.5 % yield (grams of succinate produced per gram of glucose consumed) at pH <6.2 and anaerobic conditions. Thus, we showed the potential of bacteria-based succinate fermentation under weak acidic conditions. © 2014 Springer-Verlag.
Watanabe M.,Tokushima University |
Watanabe M.,Kagawa University |
Yamamoto T.,Tokushima University |
Yamamoto A.,Tokushima University |
And 8 more authors.
Applied Biochemistry and Biotechnology | Year: 2011
The thermogenic function of brown adipose tissue (BAT) is known to be markedly elevated when animals are exposed to the cold, and intensive studies have been carried out to understand the molecular basis enabling effective thermogenesis in cold-exposed animals. In this study, we used microarray analysis to examine the effects of cold exposure of animals on their gene expression profiles in white adipose tissue (WAT), which seems to function as a counterpart tissue of BAT. The results indicate that the effects of cold exposure on the gene expression profiles of WAT were much more moderate than the effects on those of BAT. Possible reasons for the different responses of BAT and WAT to cold exposure are discussed. © Springer Science+Business Media, LLC 2011.
Yoshida K.,Taisei Corporation |
Sakamoto S.,Japan National Institute of Advanced Industrial Science and Technology |
Kawai T.,Japan National Institute of Advanced Industrial Science and Technology |
Kobayashi Y.,Japan Bioindustry Association |
And 9 more authors.
Frontiers in Plant Science | Year: 2013
Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARYWALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall.The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. © 2013 Yoshida, Sakamoto, Kawai, Kobayashi, Sato, Ichinose, Yaoi, Akiyoshi-Endo, Sato, Takamizo, Ohme-Takagi and Mitsuda.
Obana E.,Tokushima University |
Hada T.,Tokushima University |
Yamamoto T.,Tokushima University |
Kakuhata R.,Tokushima University |
And 4 more authors.
Biotechnology Letters | Year: 2012
For proper evaluation of the results of microarray experiments, it is important to understand how the signal intensities of individual probes are determined. Our previous studies revealed that signal intensities of individual probes in the Agilent array system (code G4131F) are largely dependent upon the location of the probes in the mRNA. In the present study, we examined the properties of signal intensities of individual probes in an Affymetrix array system (GeneChip Rat Gene 1. 0 ST Array), in which a random primer fused to the T7 promoter sequence is employed. Distinct from the Agilent array system, individual probes used in this Affymetrix array system did not show the probe-location effects, but gave relatively diverse signal intensities. However, the diversities of the signal intensities of these individual probes were not due to experimental error. © 2011 Springer Science+Business Media B.V.