Biosci Biotechnol Biochem [journal]
- Increased enzyme production under liquid culture conditions in the industrial fungus Aspergillus oryzae by disruption of the genes encoding cell wall α-1,3-glucan synthase. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 21.:1-11.
Under liquid culture conditions, the hyphae of filamentous fungi aggregate to form pellets, which reduces cell density and fermentation productivity. Previously, we found that loss of α-1,3-glucan in the cell wall of the fungus Aspergillus nidulans increased hyphal dispersion. Therefore, here we constructed a mutant of the industrial fungus A. oryzae in which the three genes encoding α-1,3-glucan synthase were disrupted (tripleΔ). Although the hyphae of the tripleΔ mutant were not fully dispersed, the mutant strain did form smaller pellets than the wild-type strain. We next examined enzyme productivity under liquid culture conditions by transforming the cutinase-encoding gene cutL1 into A. oryzae wild-type and the tripleΔ mutant (i.e. wild-type-cutL1, tripleΔ-cutL1). A. oryzae tripleΔ-cutL1 formed smaller hyphal pellets and showed both greater biomass and increased CutL1 productivity compared with wild-type-cutL1, which might be attributable to a decrease in the number of tripleΔ-cutL1 cells under anaerobic conditions.
- Cortisone and dexamethasone inhibit myogenesis by modulating the AKT/mTOR signaling pathway in C2C12. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 21.:1-7.
Myogenesis occurs in both the prenatal and postnatal periods and the prenatal myogenesis is related to the postnatal myogenesis and the incidence of disease later in life. Glucocorticoids used as therapeutic agents for many diseases, but cause adverse effects on muscle homeostasis, including defects in fetal muscle development. The action of glucocorticoids on differentiated skeletal muscle was well studied, but their effects on myotube formation have not been well investigated. Dexamethasone (DEX) and cortisone (COR), two synthetic therapeutic glucocorticoids, suppress myotube formation in C2C12 cells. Both COR and DEX attenuated myotube formation through modulation of myogenic regulatory factors. In addition, they affected the IGF/PI3K/AKT/mTOR signaling pathway, resulting in increased proteolytic protein (atrogin-1 and MURF1) for muscle degradation and decreased ribosomal S6 phosphorylation. The current results conclude that COR and DEX inhibit myotube formation in C2C12 cells by modulating both the myogenic program via MRFs and protein metabolism via IGF/PI3K/AKT/mTOR signaling pathway.
- Application of polydimethylsiloxane-based optical system for measuring optical density of microbial culture. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 21.:1-4.
The performance of recently developed polydimethylsiloxane (PDMS)-based optical system was tested for measuring optical density of microbial culture. The data showed that PDMS-based spectrometer is superior to "one drop" spectrometers in the accuracy, and has an advantage over conventional spectrometers in measuring dense culture without dilution.
- Urinary excretion ratio of xanthurenic acid/kynurenic acid as a functional biomarker of niacin nutritional status. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 18.:1-9.
The present study was conducted to survey functional biomarkers for evaluation of niacin nutritional status. Over 500 enzymes require niacin as a coenzyme. Of these, we chose the tryptophan degradation pathway. To create niacin-deficient animals, quinolinic acid phosphoribosyltransferase-knock out mice were used in the present study because wild type mice can synthesize nicotinamide from tryptophan. When the mice were made niacin-deficient, the urinary excretion of xanthurenic acid (XA) was extremely low compared with control mice; however, it increased according to the recovery of niacin nutritional status. The urinary excretion of kynurenic acid (KA) was the reverse of XA. Kynurenine 3-monooxygenase, which needs NADPH, was thought to be suppressed by niacin deficiency. Thus, we calculated the urinary excretion ratio of XA:KA as a functional biomarker of niacin nutrition. The ratio increased according to recovering niacin nutritional status. Low values equate with low niacin nutritional status.
- An improved glucose transport assay system for isolated mouse skeletal muscle tissues. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 18.:1-7.
There is a growing demand for a system in the field of sarcopenia and diabetes research that could be used to evaluate the effects of functional food ingredients that enhance muscle mass/contractile force or muscle glucose uptake. In this study, we developed a new type of in vitro muscle incubation system that systemizes an apparatus for muscle incubation, using an electrode, a transducer, an incubator, and a pulse generator in a compact design. The new system enables us to analyze the muscle force stimulated by the electric pulses and glucose uptake during contraction and it may thus be a useful tool for analyzing the metabolic changes that occur during muscle contraction. The system may also contribute to the assessments of new food ingredients that act directly on skeletal muscle in the treatment of sarcopenia and diabetes.
- Cloning, expression, and characterization of Aureobasidium melanogenum lipase in Pichia pastoris. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 18.:1-10.
cDNA of Aureobasidium melanogenum lipase comprises 1254 bp encoding 417 amino acids, whereas genomic DNA of lipase comprises 1311 bp with one intron (57 bp). The lipase gene contains a putative signal peptide encoding 26 amino acids. The A. melanogenum lipase gene was successfully expressed in Pichia pastoris. Recombinant lipase in an inducible expression system showed the highest lipase activity of 3.8 U/mL after six days of 2% v/v methanol induction. The molecular mass of purified recombinant lipase was estimated as 39 kDa using SDS-PAGE. Optimal lipase activity was observed at 35-37 °C and pH 7.0 using p-nitrophenyl laurate as the substrate. Lipase activity was enhanced by Mg(2+), Mn(2+), Li(+), Ca(2+), Ni(2+), CHAPS, DTT, and EDTA and inhibited by Hg(2+), Ag(+), SDS, Tween 20, and Triton X-100. The addition of 10% v/v acetone, DMSO, p-xylene, and octanol increased lipase activity, whereas that of propanol and butanol strongly inhibited it.
- Regulatory effects of the L-lysine metabolites, L-2-aminoadipic acid and L-pipecolic acid, on protein turnover in C2C12 myotubes. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 18.:1-8.
We previously showed that L-lysine (Lys) and a metabolite of Lys, L-saccharopine, suppressed autophagic proteolysis in C2C12 myotubes. However, the effects of other metabolites of Lys on protein turnover were unknown. We here investigated the effect of the Lys metabolites, L-2-aminoadipic acid (2-AA) and L-pipecolic acid (Pip), on protein turnover in C2C12 myotubes. 2-AA suppressed myofibrillar protein degradation evaluated by the 3-methylhistidine and autophagy activity evaluated by light chain 3-II at lower concentration (100 μM) than did Lys. On the other hand, Pip stimulated the mammalian target of rapamycin signaling activity. Additionally, 100 μM Pip significantly increased the rates of protein synthesis whereas 100 μM Lys had no effect. These results indicate that in C2C12 myotubes, 2-AA could suppress autophagy and Pip could stimulate the rates of protein synthesis, and these metabolites may contribute to exert effect of Lys on protein turnover.
- A non-radioactive assay for selenophosphate synthetase activity using recombinant pyruvate pyrophosphate dikinase from Thermus thermophilus HB8. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 13.:1-3.
Biosynthesis of selenocysteine-containing proteins requires monoselenophosphate, a selenium-donor intermediate generated by selenophosphate synthetase (Sephs). A non-radioactive assay was developed as an alternative to the standard [8-(14)C] AMP-quantifying assay. The product, AMP, was measured using a recombinant pyruvate pyrophosphate dikinase from Thermus thermophilus HB8. The KM and kcat for Sephs2-Sec60Cys were determined to be 26 μM and 0.352 min(-1), respectively.
- Quercetin 3,7-O-dimethyl ether from Siegesbeckia pubescens suppress the production of inflammatory mediators in lipopolysaccharide-induced macrophages and colon epithelial cells. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 13.:1-7.
Siegesbeckia pubescens (Compositae) is an annual herb indigenous to Korean mountainous regions. Recent reports have been issued on some compounds derived from S. pubescens for its anti-inflammatory activity or mode of action. The quercetin 3,7-O-dimethyl ether (QDE) isolated from the herbs of S. pubescens suppressed the lipopolysaccharide (LPS)-induced nitric oxide and inducible nitric oxide synthase (iNOS) protein production in mouse macrophages. QDE downregulated pro-inflammatory cytokines such as interleukin (IL)-6, IL-1β, tumor necrosis factor -α levels in LPS-stimulated macrophages. Also, QDE decreased the expression of LPS-induced iNOS and cyclooxygenase-2 (COX-2) protein and the production of IL-8 in LPS-induced HT-29 cells. Macrophages and colon epithelial cells are important for regulating the colon immune systems, thus QDE may regulate inflammatory colon disease via LPS-induced inflammation in macrophages and colon epithelial cells. QDE, anti-inflammatory constituent of S. pubescens herbs, can be expected to be a potential candidate for therapeutics against inflammatory bowel disease.
- Ginsenoside Re improves skin barrier function in HaCaT keratinocytes under normal growth conditions. [JOURNAL ARTICLE]
- Biosci Biotechnol Biochem 2016 Jul 13.:1-3.
Ginsenoside Re (Re), a major ginsenoside of ginseng, enhanced the cornified cell envelope (CE) formation in HaCaT keratinocytes under normal conditions. In HaCaT keratinocytes, Re was also able to upregulate filaggrin protein and caspase-14 activity in a concentration-dependent manner. These findings reasonably imply that Re possesses a desirable property of improving skin barrier function.