• Journal of Food Hygiene and Safety
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• v.1 no.1
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• pp.13-21
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• 1986

Two short-term bioassays were employed to asses the mutagenic and clastogenic activities in browning reaction of pentose-creatine, pentose-glycine and pentose-creatine-glycine browning reaction model system. Methylene chloride extract of rhamnose-creatine-glycine browning reaction exhibited the strongest mutagenicity toward Salmonella typhimurium TA98 with S-9. Methylene chloride extract of pentose-creatine and pentose-glycine browning reaction solutions was also tested for mutagenicity, with positive responses. Methylene chloride extract of pentose-creatine-glycine browning reaction solutions induced significant increase in chromosome aberrations in the treated Chinese hamster ovary(CHO) cells. Each of pentose-creatine and pentose-glycine browning reaction solutions induced a relatively low frequency of chromosome aberrations in the treated cells.

• Clinical and Experimental Reproductive Medicine
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• v.39 no.2
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• pp.58-67
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• 2012

Objective: Previously, we identified that transketolase (Tkt), an important enzyme in the pentose phosphate pathway, is highly expressed at 2 hours of spontaneous maturation in oocytes. Therefore, this study was performed to determine the function of Tkt in meiotic cell cycle regulation, especially at the point of germinal vesicle breakdown (GVBD). Methods: We evaluated the loss-of-function of Tkt by microinjecting Tkt double-stranded RNAs (dsRNAs) into germinal vesicle-stage oocytes, and the oocytes were cultured in vitro to evaluate phenotypic changes during oocyte maturation. In addition to maturation rates, meiotic spindle and chromosome rearrangements, and changes in expression of other enzymes in the pentose phosphate pathway were determined after Tkt RNA interference (RNAi). Results: Despite the complete and specific knockdown of Tkt expression, GVBD occurred and meiosis was arrested at the metaphase I (MI) stage. The arrested oocytes exhibited spindle loss, chromosomal aggregation, and declined maturation promoting factor and mitogen-activated protein kinase activities. The modified expression of two enzymes in the pentose phosphate pathway, Prps1 and Rbks, after Tkt RNAi and decreased maturation rates were amended when ribose-5-phosphate was supplemented in the culture medium, suggesting that the Tkt and pentose phosphate pathway are important for the maturation process. Conclusion: We concluded that Tkt and its associated pentose phosphate pathway play an important role in the MI-MII transition of the oocytes' meiotic cell cycle, but not in the process of GVBD.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.385-392
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• 1996

Bacillus stearotheymophilus, a potent xylanolytic bacterium isolated from soil, was tested for the strain's strategies of pentose utilization and the evidence of substrate preferences. The strain metabolized glucose, xylose, ribose, maltose, cellobiose, sucrose, arabinose and xylitol. The efficacy of the sugars as a carbon and energy source in this strain was of the order named above. The organism, however, could not grow on glycerol as a sole growth substrate. During cultivation on a mixture of glucose and xylose or arabinose, the major hydrolytic products of xylan, B. stearothermophilus displayed classical diauxic growth in which glucose was utilized during the first phase. On the other hand, the pentose utilization was prevented immediately upon addition of glucose. Cellobiose was preferred over xylose or arabinose. In contrast, maltose and pentose were co-utilized, and also no preference on between xylose and arabinose. Enzymatic studies indicated that B. stearothermophilus possessed constitutive hexokinase, a key enzyme of the glucose metabolic system. While, the production of $^{D}$-xylose isomerase, $^{D}$-xylulokinase and $^{D}$-arabinose isomerase essential for pentose phosphate pathway were induced by xylose, xylan, and xylitol but repressed by glucose. Taken together, the results suggested that the sequential utilization of B. stearothermophilus would be mediated by catabolite regulatory mechanisms such as catabolite inhibition or inducer exclusion.

• New & Renewable Energy
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• v.9 no.1
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• pp.25-32
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• 2013

It is indispensable to increase the conversion rate of a reducing sugars such as pentose and hexose derived from cellulosic wastes for a highly efficient bioethanol fermentation from food wastes. The saccharification liquid from cellulosic substrates such as vegetable food wastes contained lots of hexose like glucose and pentose like xylose. Since Saccharomyces-based yeasts could not convert xylose to bioethanol, Pichia stipitis which could directly ferment xylose to ethanol was chosen. After selecting Saccharomyces coreanus and P. stipitis, fermentation characteristics by mixture of two yeasts were investigated. As a result, it was verified the production of ethanol was enhanced by the co-fermentation, although there were somewhat differences between the fermentation characteristics by the aeration methods. Moreover, the consumption of pentose, hexose and disaccharide was obviously observed, and aeration in the process of fermentation seemed to stimulate the activity of P. stipitis.

• Journal of Plant Biology
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• v.12 no.2
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• pp.15-22
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• 1969

By spectrophotometric assay method, the following enzymes could be detected in Dunaliella tertiolecta and Chlorella pyrenoidosa cell-free extracts: Hexokinase; Glucose-6-phosphate, 6-Phosphogluconate and Triosephosphate dehydrogenase; Transketolase; Phosphogluco and Ribosephosphate isomerase; Phosphoglucomutase; Phosphofructokinase; Fructosediphosphate aldorase and Ribulosephosphate 3-epimerase. Such enzymes are in accordance with the proposed pathway of glucose catabolism by D. tertiolecta as well as C. pyrenoidosa. Also, it could be estimated, under the presence of NADP, that pentose phosphate pathway were more active than glycolytic pathway in D. tertiolecta cell-free systems.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.158-162
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• 1986

Various cell wall polysaccharides such as ionically associated pectin (IAP), covalently bounded pectin (CBP),4N potassium hydroxide soluble hemicellulosic fraction (HF,) and 0-3N soluble hemicellulosic fraction (HF,) were fractionated from crude cell wall of the fresh and soft persimmon by chemical method. The changesin cell wall polysaccharides were studied by gel filteration chromatography . The content of crude cell wall remarkably decreased in the soft persimmon. The decreasing rates of IAP, CBP and $HF_2$ were 59, 60 and 74%, respectively, while $HF_1$ and cellulose changed only a little during softening. Sugar compositions of IAP and CBP were 72-84% uronic acid, 5-1% hexose and 11-16% pentose, and also the hemicellulose was composed of uronic acid besides hexose and pentose that was hemicellulosic components. The loss rate of pentose in IAP, of hexose in CBP, of hexose and uronic acid in $HF_2$, of pentose in $HF_1$ increased during softening. Though apparent average molecular freight of all polysaccharides shifted from high molecular freight to low molecular weight polymer, the shifting degree of CBP and $HF_2$ was especially remarkable during softening. It is suggested that the severe softening phenomenon of persimmon involved the degradation and dissolution of wall bound-CBP and $HF_2$ which were associated with each other.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.203-207
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• 2010

A number of bacterial species coexist in oral cavities as a biofilm rather than a planktonic arrangement. By forming an oral biofilm with quorum sensing properties, microorganisms can develop a higher pathogenic potential and stronger resistance to the host immune system and antibiotics. Hence, the inhibition of biofilm formation has become a major research issue for the future prevention and treatment of oral diseases. In this study, we investigated the effects of pentose on biofilm formation and phenotypic changes using wild type oral bacteria obtained from healthy human saliva. D-ribose and D-arabinose were found to inhibit biofilm formation, but have no effects on the growth of each oral bacterium tested. Pentoses may thus be good candidate biofilm inhibitors without growth-inhibition activity and be employed for the future prevention or treatment of oral diseases.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.65-71
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• 2009

Microbial oxidoreductive systems have been widely used in asymmetric syntheses of optically active alcohols. However, when reused in multi-batch reaction, the catalytic efficiency and sustainability of non-growing cells usually decreased because of continuous consumption of required cofactors during the reaction process. A novel method for NADPH regeneration in cells was proposed by using pentose metabolism in microorganisms. Addition of D-xylose, L-arabinose, or D-ribose to the reaction significantly improved the conversion efficiency of deracemization of racemic 1-phenyl-1,2-ethanediol to (S)-isomer by Candida parapsilosis cells already used once, which afforded the product with high optical purity over 97%e.e. in high yield over 85% under an increased substrate concentration of 15 g/l. Compared with reactions without xylose, xylose added to multi-batch reactions had no influence on the activity of the enzyme catalyzing the key step in deracemization, but performed a promoting effect on the recovery of the metabolic activity of the non-growing cells with its consumption in each batch. The detection of activities of xylose reductase and xylitol dehydrogenase from cell-free extract of C. parapsilosis made xylose metabolism feasible in cells, and the depression of the pentose phosphate pathway inhibitor to this reaction further indicated that xylose facilitated the NADPH-required deracemization through the pentose phosphate pathway in C. parapsilosis. moreover, by investigating the cofactor pool, the xylose addition in reaction batches giving more NADPH, compared with those without xylose, suggested that the higher catalytic efficiency and sustainability of C. parapsilosis non-growing cells had resulted from xylose metabolism recycling NADPH for the deracemization.

• Biomolecules & Therapeutics
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• v.26 no.1
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• pp.29-38
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• 2018

During cancer progression, cancer cells are repeatedly exposed to metabolic stress conditions in a resource-limited environment which they must escape. Increasing evidence indicates the importance of nicotinamide adenine dinucleotide phosphate (NADPH) homeostasis in the survival of cancer cells under metabolic stress conditions, such as metabolic resource limitation and therapeutic intervention. NADPH is essential for scavenging of reactive oxygen species (ROS) mainly derived from oxidative phosphorylation required for ATP generation. Thus, metabolic reprogramming of NADPH homeostasis is an important step in cancer progression as well as in combinational therapeutic approaches. In mammalian, the pentose phosphate pathway (PPP) and one-carbon metabolism are major sources of NADPH production. In this review, we focus on the importance of glucose flux control towards PPP regulated by oncogenic pathways and the potential therein for metabolic targeting as a cancer therapy. We also summarize the role of Snail (Snai1), an important regulator of the epithelial mesenchymal transition (EMT), in controlling glucose flux towards PPP and thus potentiating cancer cell survival under oxidative and metabolic stress.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.34-39
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• 1992

For the screening of new-functional and specific exopolysaccharide, a bacterium strain was isolated from soil through the two steps of screening. The isolated bacterium was identified as Bacillus polymyxa KS-1 according to the criteria of morphological, physiological, and chemical taxonomic analyses. The exopolysaccharide was composed of glucose:galactose: mannose and galactosamine in an approximate molar ratio of 1.00:0.36:1.02:1.10. The produced exopolysaccharide by Bacillus polymyxa KS-1 was found to be revealed new acidic polysaccharide which did not contain pentose, ketose, starch, and uronic acid.