Soy Protein Research(Japan)

34-1

Prospective Study of Preventive Eff ect of Intensive Dietary Soy Intakes on Atherosclerosis in an Urban General Population (Part III)

Yoshihiro KOKUBO*1, Yoko HURUKAWA2 and Mariko BANNO3

1Department of Preventive Cardiology, National Cerebral and Cardiovascular Center, Osaka 565-0873
2Faculty of Health Science, Kyoto Koka Women's University, Kyoto 615-0882
3School of Human Environmental Sciences, Department of food Science and Nutrition, Mukogawa Women's University, Nishinomiya 663-8558

ABSTRACT
Background and Purpose : Intervention studies have revealed dietary soy to be inversely associated with the risks of dyslipidemia and cardiovascular disease. However, there has been no study with regard to the association between dietary soy and the extension of atherosclerosis as a prospective study. We studied the association between dietary soy intake and the increase of atherosclerosis in a general urban Japanese cohort. Methods : We studied 2,467 men and women who underwent a medical examination as a baseline survey between April 2001 and March 2003. Each subject completed a food frequency questionnaire. The soy products included: miso soup, tofu, and natto. Hypertension was defined as the mean of the 2nd and the 3rd blood pressures ≥ 140/90 mmHg or antihypertensive drug use. Diabetes was defi ned as fasting blood glucose ≥ 126 mg/100mL, occasional blood glucose ≥ 200 mg/100mL, or anti-diabetic medication. Dyslipidemia was defined as non-HDL cholesterol ≥ 170 mg/100mL. All study participants were invited every 2 years to undergo a routine health check-up until March 2013. Carotid atherosclerosis was evaluated by high-resolution ultrasonography with atherosclerotic indexes of IMT in the common carotid artery (CCA), carotid artery bulb, and internal and external carotid arteries. Mean IMT was defined as the mean of the IMT of the proximal and distal walls for both sides of the CCA at a point 10 mm proximal to the beginning of the dilation of each carotid artery bulb. Max-CCA and Max-IMT were defi ned as the maximum IMT in the CCA and the entire scanned area, respectively. The changes of IMT were calculated by logistic regression model. The risks of carotid atherosclerosis (cut-off point for 1.1 mm of mean CCA IMT) throughout the study were compared by the use of multivariable-adjusted Cox proportional-hazards models. Results : The mean plaque scores for the lowest and highest quartiles of miso soup were 2.3 and 2.0, respectively (P=0.05) in women. Compared with the lowest quartiles of dietary tofu intake in women, the changes of mean IMT for the second and third quartiles of tofu intake in womaen, statistically significant in women (-0.022 mm and -0.019 mm, p <0.05). Compared with the lowest quartiles of dietary natto intake in women, the mean changes of mean IMT for the third and fourth quartiles of natto intakes were -0.015 mm and -0.017 mm, respectively (p <0.05), and the mean changes of Max-IMT at bifurcation for the third and fourth quartiles of natto intakes were -0.091 mm and -0.092 mm, respectively (p <0.05). The multivariable adjusted hazard ratios (95% confidence intervals) for carotid atherosclerosis at CCA (1.1 mm or more) among the second and the third quartiles of miso soup intake were 0.48 (0.26-0.88) and 0.52 (0.30-0.90), respectively, compared with the fi rst quartile of miso soup intake in women. Conclusions : In this prospective cohort study, we observed a preventive eff ect of carotid atherosclerosis among women with higher soy intakes, especially natto and miso soup.
Soy Protein Research, Japan 16 , 1-6, 2013.

Key words : Soy product (miso soup, natto), Carotid atherosclerosis, prospective cohort study, population
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34-2

Study of the Molecular Targets of Metabolic Improvement Caused by Soy Protein Intake (Part II)

Ryuichiro SATO*1, Makoto SHIMIZU1, Hiroyasu INOUE2 and Rieko NAKATA2

1Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657
2Department of Food Science and Nutrition, Faculty of Human Life and Environment Nara Women's University, Nara 630-8506

ABSTRACT
In the current experiments we used β-conglycinin as a dietary protein source by comparing casein with it. When C57BL/6N mice were fed a high-fat diet containing either casein or β-conglycinin for 9 weeks, the β-conglycinin diet lowered serum glucose, cholesterol, and insulin concentrations, and weight gain. The β-conglycinin diet produced positive changes in hepatic gene expression as reported previously. Oral glucose tolerance test revealed that orally loaded glucose was more rapidly cleared in mice fed the β-conglycinin diet, suggesting that this diet stimulated insulin sensitivity and improved insulin tolerance. When mice were fed the β-conglycinin diet for 6 hours after 24-hour fasting, hepatic gene expression of fibroblast growth factor (FGF) 21 was significantly increased in the β-conglycinin diet mice. Because this gene is one of the PPARα targets, PPARα-deficient mice were fed the β-conglycinin diet to determine whether PPARα is activated by β -conglycinin feeding. We found that neither an increase in FGF21 mRNA nor most effects of the β-conglycinin diet were abolished by PPARα-deficiency, suggesting that β-conglycinin may exert its benefi cial effects without involving PPARα. These results indicate that increased FGF21 induced by β-conglycinin feeding may account for lowering body weight gain and serum glucose level caused by a high fat diet.
Soy Protein Research, Japan 16, 7-11, 2013.

Key words : β-conglycinin, FGF21, PPARα

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34-3

Water Soluble Fiber is Useful as a Cooking Ingredient as well as a Dietary Fiber Source (PartI)

Masayo KANEDA*1, Eiko MURAI2, Chieko TOYAMA3, Misako HIROTA4, Yoko MATSUMURA5, Sayako AOKI6, Chise SHIMOMOTO7 and Saori HIDAKA8

1Junior College of Kagawa Nutrition University, Tokyo 170-8481
2Marugame Municipal Ayauta Junior High School, Kagawa 761-2406
3Toki Municipal Hida Elementary School, Gifu 509-5115
4Moriyama Municipal Moriyama Elementary School, Shiga 524-0041
5Omihachiman Municipal Azuchi Junior High School, Shiga 521-1341
6Katsushika Ward Kitano Elementary School, Tokyo 125-0052
7Tsuno Municipal Higashitsuno Junior High School, Kochi 785-0501
8Yasu Municipal Chuzu Elementary School, Shiga 520-2412

ABSTRACT
Currently, it is difficult to meet dietary fiber intakes in school meals in elementary and junior high school. In our previous study, we found that Soluble Fiber Okara (SOF) increases dietary fiber while maintaining workability as well as increasing palatability. We conducted a study of a cooking method taking advantage of SOF's characteristics (Study 1) In addition, taste with and without SOF was investigated (Study 2). According to the results, the "adhesive", "viscous" and "water-absorbing" qualities of SOF led to an increase in the workability in cooking as well as to increased palatability. Recognizing these characteristics of SOF, nutrition teachers increased use of dietary-fiber-rich vegetables and legumes. Furthermore, decreases in consumption of energy and lipids through use of SOF were observed. Through taste surveys, we found that SOF improved taste (in fried or grilled dishes) or had no effect (in soups). From these results, we conclude that SOF can be used to improve taste as well as to increase fiber intake.
Soy Protein Research, Japan 16, 12-17, 2013.

Key words : school lunch, okara, byproduct of tofu fiber, soluble fiber, nutrition teacher, school children cook
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34-4

Molecular Dissection of High α-Tocopherol Contents in Seed Found in Wild Soybean toward Development of Cultivars with High α-Tocopherol Contents by Gene Pyramiding

Shouhei MARUYAMA, Mari HIRONO, Akiko SATO, Tetsuya YAMADA and Jun ABE*

Laboratory of Plant Genetic and Evolution, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589

ABSTRACT
Alfa tocopherol, one of four tocopherol isoforms, possesses the highest vitamin E activity in human. Soybean, Glycine max (L.) Merr., produces the seeds that contain tocopherols, of which γ-tocopherol is the most predominant isoform, and the proportion of α-tocopherol is usually less than 10% of total. Molecular analysis for an elevated α-tocopherol content detected in a soybean germplas m collection has revealed that this trait is controlled by the elevated expression level of γ-tocopherol methytransferase-3 gene (γ-TMT3) in developing cotyledons during maturation. We found wild soybean (ssp. soja) accessions that produced seeds with higher levels of α-tocopherol content than those observed in the cultivated germplasm, through a survey of wild soybean germplasm collection. We have sequenced the promoter region of γ-TMT3 gene for 11 accessions, and classifi ed these accessions into four haplotypes. Segregation analysis for F2 of the cross between a soybean breeding line and a wild accession with highα-tocopherol content revealed that the high content of wild soybean is controlled by a number of genes, one of which is closely associated with a DNA marker for γ-TMT3. The wild accessions further exhibited a variation for thermo-sensitivity between constant temperatures of 25 and 30 degree C during maturation. The molecular mechanism for the thermo-sensitivity is currently being researched. The use of wild accessions may contribute to the breeding of a cultivar which stably produces seeds with elevated α-tocopherol content.
Soy Protein Research, Japan 16, 18-22, 2013.

Key words : Soybean, Glycine max, α-tocopherol, Vitamin E, Genetic diversity
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34-5

Production of Novel Mutants Useful for Improving Seed Components in Soybean

Mayumi TSUCHIYA, Megumi KASAI and Akira KANAZAWA*

Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589

ABSTRACT
Soybean is thought to be derived from an ancestral plant(s) with a tetraploid genome, and as a consequence, large portions of the soybean gen ome are duplicated with nearly 75% of the genes present in multiple copies. It is conceivable that such a duplicated nature of the genome is a constraint on mutant production by conventional methods of mutagenesis such as γ-ray or X-ray irradiation as well as chemical treatments. However, ion-beam irradiation is expected to cause genomic changes that are more drastic than those induced by conventional mutagenesis. In these circumstances, we have started a series of analyses to examine whether ion-beam irradiation is effective in producing mutants in soybean. We have optimized irradiation conditions and produced plant populations, which are potentially useful for breeding and/or identifying gene function. Plants that had visibly altered phenotypes were screened in the M2 generation. Here, we examined whether seed components are altered in these mutants. We analyzed contents of isoflavones, proteins, fatty acids and starch in dried seeds. We found a decrease in Isoflavone content, an increase in protein content, and both an increase a nd a decrease in fatty acid content in the mutants. These mutants potentially confer genetic changes that are useful for improving soybean seed components.
Soy Protein Research, Japan 16, 23-29, 2013.

Key words : chlor ophyll deficiency, ion-beam irradiation, mutagenesis, seed components, soybean
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34-6

Metabolic Breeding Research Using Metabolome Data of Glycine Soja

Yuji SAWADA*12

1RIKEN Plant Science Center, Yokohama 230-0045
2RIKEN Center for Sustainable Resource Science, Yokohama 230-0045

ABSTRACT
Metabolomics is a methodology for comprehensive detection and quantifi cation of all detectable metabolites in an organism. We have established a high throughput metabolomics platform, which we have named "widely targeted metabolomics". Using this methodology, we can detect several hundred standard compounds by high sensitivity detection mode: selected reaction monitoring (SRM) of a tandem quadrupole mass spectrometer. We have also established a novel algorithm, which can be managed for several thousand SRM conditions. This algorithm allowed us to detect an un-targeted tandem mass spectrum (MS/MS) as an integrated SRM (iSRM). Moreover, we have established a MS/MS database for assignment of candidate structures (http://spectra.psc.riken.jp/). In a previous study, we carried out the SRM and iSRM assay for soybean seed, and the metabolite quantitative trait locus (mQTL) analysis successfully identified by mapping populations which have been constructed from Glycine max and Glycine soja (National BioResource Project). In this study, we try to identify the specific metabolite accumulation patterns in seeds. The G. max and G. soja seeds were separated into cotyledon and seed coat, and the tissues were used for metabolic profi ling. Principal component analysis (PCA) was conducted using the metabolome data. Using score plot, the Principal component 1 was clearly separated from the cotyledon and seed coat samples. To elucidate important metabolites, we carried out regression analysis: Partial least squares (PLS). The results suggested that sugar, nucleotide, and malonyl isoflavone were major components in cotyledon. The anthocyanin pigment and non-proteogenic amino acid were accumulated in the seed coat.
Soy Protein Research, Japan 16, 30-34, 2013.

Key words : Metabolomics, seed coat, cotyledon, G. max, G. soja., multivariate analysis
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34-7

Oligosaccharide Elicitor Perception Systems for Herbivory Defense in Soybeans

Gen-ichiro ARIMURA1,2, Tatsuya SAWASAKI3, Abdelaziz RAMADAN3, Keiichiro NEMOTO3, Hiroyuki TAKEDA3 and Massimo E. MAFFEI4

1Center for Ecological Research, Kyoto University, Otsu 520-2113
2Department of Biological Science & Technology, Faculty of Indus trial Science & Technology, Tokyo University of Science, Tokyo 125-8585
3Cell-free Science and Technology Research Center, Ehime Univers ity, Matsuyama 790-8577
4University of Turin, Turin 10135, Italy

ABSTRACT
Upon herbivore attack, plants respond to herbivore-derived factors including chemical elicitors included in their saliva. In plants, immunity is initiated through pattern recognition receptors in response to herbivory to provi de the first line of inducible defense. Despite the numerous elicitors perceived by plants, however, no pattern recognition receptors for insect salivary elicitors have been identified so far. As factors present in Spodoptera littoralis oral secretions (including a putative beta-galactofuranose polysaccharide) are predicted to be among the insect salivary elicitors and a receptor kinase CERK1 (Chitin Elicitor Receptor Kinase) has been identified as critical receptors for oligosaccharide signaling in plants, in the current study we screened the characteristics of soybean CERK1-homolosous (receptor-like kinase [RLK]) genes which enabled interaction with a component in the regurgitant of S. littoralis. The recombinant proteins of 24 members of soybean cDNAs (Arabidopsis CERK1 homologues), fused with glutathione S-transf erase (GST) and FLAG tag at the C-terminus, were successfully synthesized in vitro transcription and cell-free protein synthesis. The synthesized proteins were analyzed with the biacore system that enables to find the ability of the biomolecule to interact with a binding protein. Our preliminary analysis showed that some of the twenty-four CERK1-homologous proteins interacted with regurgitant component(s) from S. littoralis. We intend to establish the biacore system to identify with certainty the receptor candidates, and mine other sets of potent receptors involved in elicitor recognition in plant cells.
Soy Protein Research, Japan 16, 35-38, 2013.

Key words : elicitors, herbivore, oligosaccharide, receptor-like kinase, soybean
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34-8

Analysis of Molecular Mechanisms of Plant Parasitic Nematode In fection Steps

Shinichiro SAWA*

Graduate school of Science and Technology, Kumamoto University, Kumamoto 860-8555

ABSTRACT
Because of their agricultural importance, the soybean cyst nematode Heterodera glycines that infects soybean (Glycine max) and Meloidogyne incognita that infects many crops have emerged as good research models to understand the signaling, perception, and response events during plant-nematode interactions. The recent advances in our understanding of the cellular, physiological, and molecular basis of legume-nematode interactions are merging at the crossroads of plant-microbe interactions and plant developmental biology. The CLE peptide hormone is the molecule responsible for the control of plant meristem activity, and CLE genes are conserved in many plants. However, in the animal kingdom, only nematodes that are infective to plants has CLE gene. This CLE gene of nem atodes is likely to be functional in plants. Once nematodes infect roots, they make root cells into multinucleated giant cells, as source of nutrition, by injection of various redifferentiation factors thought to be involved CLE peptides of nematodes. Here we have performed genetic screening to isolate nematode infection resistant mutants from Arabidopsis thaliana. In the first screening, we isolated 25 putative nematode infection resistant mutants. We performed the resistance three times, and we have isolated four candidates for nematode infection resistant mutant of Arabidopsis. Furthermore, we also screened many chemicals that guide root knot nematode. We have developed devices to evaluate the nematode guidance activity, and one guidance behavior was confirmed when the nematodes are packed in a small space. If we isolate the chemical, we will be able to develop new agricultural chemicals that can difend agianst the nematode damage.
Soy Protein Research, Japan 16, 39-42, 2013.

Key words : nematode, Arabidopsis, CLE, molecular mechanism, chemical
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34-9

Effects of Soy Protein Isolate on Glucose Homeostasis and Kidney Functions of ZDF Rats

Masatoshi KUBOTA*1, Miki YAMAGUCHI2, Reiko WATANABE*3, Shinobu FUJIMURA1,2 and Motoni KADOWAKI1,2

1Center for Transdisciplinary Research, Niigata University, Niigata 950-2181
2Graduate School of Science and Technology, Niigata University, Niigata 950-2181
3Department of Health and Nutrition, University of Niigata Prefecture, Niigata 950-8680

ABSTRACT
Type 2 diabetes mellitus (T2DM) is a serious disease caused by lifestyle and genetic factors. T2DM leads to various complications such as diabetic retinopathy, neuropathy and nephropathy. In Japan the restriction of dietary protein intake is recommended in order to control the progression of diabetic nephropathy. However, the effect of the kinds of proteins on controlling diabetic nephropathy has been unclear. Therefore, we focused on clarifying the effects of soy protein isolate (SPI) on diabetes and diabetic nephropathy. Male obese type 2 diabetic Zucker Diabetic Fatty (ZDF) rats were fed casein (C) or SPI diets for 8 wk. The following values were determined; fasting blood glucose level, blood parameters including insulin and adiponectin, the excretion of urinary albumin which is a diagnostic marker of diabetic nephropathy, and urinary N-acetyl-β-D-glucos aminidase (NAG) which is a marker of proximal renal tubule damage. Kidney tissue sections were obtained for histological analysis. SPI had beneficial effects on glucose homeostasis such as fasting blood glucose levels, hemoglobin A1c, and adiponectin. SPI significantly improved the total cholesterol level and the markers liver damage in the plasma and the accumulation of total lipids in the livers, compared with C. In addition, urinary albumin and NAG excretion in the SPI group were significantly improved, compared with those of the C group. The renal glomerular damage was significantly suppressed in the SPI group. These results show that SPI has a suppressive effect on progression of diabetes and diabetic nephropathy.
Soy Protein Research, Japan 16, 43-47, 2013.

Key words : soy protein isolate, diabetes, diabetic nephropathy, Zucker Diabetic Fatty rat
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34-10

Effects of β-Conglycinin on Lipid Metabolism and Glucose Metabolism in Rats

Kazunori KOBA*1, Eriko FUKUDA1, Sizuka TAMARU1 and Daichi OIKAWA1,2

1Faculty of Nursing and Nutrition, University of Nagasaki, Siebo ld, Nagasaki 851-2195
2Faculty of Education, Nagasaki University, Nagasaki 852-8521

ABSTRACT
Feeding of β-conglycinin, one of the major components of soy protein, has been reported to decrease body fat mass, and serum and liver triglyceride levels in rats. Dietary β-conglycinin was also observed to increase serum adiponectin concentration, which could affect glucose metabolism as well as lipid metabolism. In the present study, therefore, we investigated whether feeding β-conglycinin could affect factors influencing glucose metabolism, such as insulin sensitivity. Male Sprague Dawley rats were fed AIN-93G diets containing 20% protein; either casein (CAS), or CAS replaced soy protein isolate (SPI) or β-conglycinin (CON) at the proportion of 50% for 1 month. After a 4-week feeding period, we conducted an insulin tolerance test (ITT). Compared with CAS, SPI and more clearly CON decreased blood glucose levels 90 min after an intraperitoneal insulin injection (0.75 IU/kg body weight). The results suggested that SPI, especially CON could increase insulin sensitivity in rats. However, CON feeding affected neither fasting glucose level nor serum insulin level after the feeding period. Consistent with previous observations, dietary CON, compared with CAS, decreased white adipose tissue weights and liver triglyceride level. Therefore, results in the present study suggest that dietary CON could affect glucose metabolism as well as lipid metabolism in rats.
Soy Protein Research, Japan 16, 48-52, 2013.

Key words : β-conglycinin, insulin tolerance test, body fat mas s, liver triglyceride,, rats
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34-11

New Oligopeptides Derived from Soybean Ameliorates Hypercholest erolemia

Satoshi NAGAOKA*

Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193

ABSTRACT
This experiment was designed to identify oligopeptides which have hypocholesterolemic activity from soybean β-conglycinin. First, in HepG2 screening, we found that QEK derived from soybean β-conglycinin α'subunit exhibited the enhancement of CYP7A1 mRNA levels compared to control as a hypocholesterolemic peptide lactostatin (IIAEK). Second, we found some bile acid-binding peptides in the peptide array screening. In this context, we selected VVFLASVS to evaluate bile acid-binding ability and micellar solubility of cholesterol in vitro, using soystatin (VAWWMY) as a positive control. VVFLASVS showed higher bile acid-binding ability in vitro, than other synthesized peptides. VVFLASVS also showed significantly lower micellar solubility of cholesterol than did other synthesized peptides in vitro like the medicine cholestyramine used as a positive control. In rats, intestinal cholesterol absorption was significantly decreased by oral administration of VVFLASVS compared to control. Serum cholesterol level was significantly decreased by oral administration of VVFLASVS compared to control. Thus, we found for the first time, a novel soybean hypocholesterolemic oligopeptide, VVFLASVS in rats.
Soy Protein Research, Japan 16, 53-56, 2013.

Key words : β-conglycinin, peptide array, VVFLASVS, soystatin, bile acid, rat, QEK
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34-12

Enzymatic Conditions for Release of Vasorelaxing Peptides Derived from Soy Protein and their Physiological Functions

Kousaku OHINATA*

Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011

ABSTRACT
We previously found that dipeptide Arg-Phe (RF) has potent vasorelaxing activity. In the current study, we discovered that a vasorelaxing pentapeptide Val-Leu-Gln-Arg-Phe (VLQRF) is released by gastrointestinal protease digestion of β-conglycinin, a major storage protein of soybean. We then investigated its physiological functions. VLQRF lowered blood pressure in spontaneously hypertensive rats (SHR) after oral administration. Intriguingly, the VLQRF-induced blood pressure-lowering activity was more potent and longer-lasting than that of RF. Nitric oxide (NO) and prostaglandins are known to be endothelium-derived vasorelaxing factors; however, the VLQRF-induced vasorelaxing activity was not blocked by inhibitors of NO synthase and cyclooxygenase. The vasorelaxing activity was blocked by an antagonist for CCK, which is known as a satiety factor. Indeed, orally administered VLQRF decreased food intake. VLQRF also activated CCK-releasing enteroendocrine STC-1. VLQRF is the first soy-derived peptide having both hypotensive and anorexigenic activities.
Soy Protein Research, Japan 16, 57-61, 2013.

Key words : β-conglycinin, peptide, vasorelaxing activity, hypotensive activity, food intake regulation
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34-13

Substrate Multispecificity of the Yeast Peptide Transporter Ptr2p

Keisuke ITO*1, Takayasu MOTOYAMA2, Sayuri KITAGAWA3, Ryuji KATO1 and Yasuaki KAWARASAKI1

1School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka 422-8526
2Soy protein, Processed Foods R & D Center, Fujioil Co., LTD., I zumisano 598-8540
3Food Science Research Institute, Research & Development Division, Fujioil Co., LTD., Tsukubamirai 300-2497

ABSTRACT
Peptide uptake systems that involve members of the proton-coupl ed oligopeptide transporter (POT) family are conserved across all organisms. Due to their substrate multispecificity, it is assumed that each of these POT family transporters can recognize as many as 8,400 types of di/tripeptides, which are products generated by protein hydrolysis, at a single substrate-binding site that resides on each transporter and can actively transport these peptides. The question 'how one substrate-binding site can recognize a variety of substrates?' is the major focus in peptide transport research. However, the entire spectrum of the substrate preference of POT family transporter has not been elucidated. In this study, the substrate multispecificity of Ptr2p, a major peptide transporter of Saccharomyces cerevisiae, was characterised by a comprehensive analysis using a dipeptide library. The affinities (Ki) of di/tripeptides toward Ptr2p showed a wide distribution range from 48 mM to 0.020 mM. The result also showed that dipeptides containing aromatic amino acids and branched-chain amino acids frequently appeared in the high-affinity group. This substrate multispecificity indicated that Ptr2p plays an important role in the preferential uptake of vital amino acids, which imposes a biosynthesis burden on yeasts.
Soy Protein Research, Japan 16, 62-67, 2013.

Key words : peptide transporter, Ptr2p, substrate multispecificity, soy peptides, Saccharomyces cerevisiae
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34-14

A Mechanism for Estrogen Receptor-Independent Action of Soy Isoflavone

Hirofumi TACHIBANA*1,2, Shuya YAMASHITA1 and Koji YAMADA1

1Faculty of Agriculture, Kyushu University, Fukuoka 812-8581
2Food Functional Design Research Center, Kyushu University, Fukuoka 812-8581

ABSTRACT
Daidzein and genistein are polyphenolic Isoflavones contained in soy, and daidzein is metabolized to equol by intestinal bacteria. The mechanisms of the physiological effects of isoflavones have been considered to be involved in estrogen receptors (ERs) in many instances, because of their avidity for ERs. On the other hands, some reports indicate the existence of ER-independent effects of isoflavones. We identified a pap-associated domain containing 5 (Papd5), one of the non-canonical poly(A) polymerases, as a responsive gene for ER-independent growth-inhibitory action of equol in cancer cells. In ER-positive human cervical cancer MCF-7 cells, Papd5 ablation did not affect the expression level of ERα and the equol-induced expressi on of ERα target genes. In ER-negative human cervical HeLa cells, equol induced adenylation of small nucleolar RNA (snoRNA) SNORA68 Papd5-dependently, whereas genistein and green tea (-)-epigallo catechin 3-O-gallate had no effect. These results suggest that Papd5 has no involvement in the ER-agonistic effect of equol and equol inhibits cancer cell growth through activation of Papd5.
Soy Protein Research, Japan 16, 68-72, 2013.

Key words : isoflavone, estrogen receptor, anticancer effect, Papd5, poly adenylation
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34-15

Chrono-Nutrition Effects of Protein-Rich Food on Mouse Circadian Rhythm

Shigenobu SHIBATA* and Mari KUWAHARA

Laboratory of Physiology and Pharmacology, Department of electrical Engineering and Biosciences, School of Advanced Biosciences and Engineering, Waseda University, Tokyo 162-8480

ABSTRACT
The rotation of the earth around its axis causes 24 h changes in environmental conditions including temperature, food availability, light, and darkness. In addition, seasonal changes in the length of day occur as a consequence of the earth orbiting the sun. In order to cope with and anticipate these changes, most organisms throughout the plant and animal kingdom possess a circadian tim ing system. The peripheral circadian clock in mice is affected not only by light-dark cycles but also by chemicals and foods. It is known that estrogen influences circadian rhythm through estrogen receptors. Then, we examined the effect of soy isoflavone (Soyafl avon HG, obtained from Fuji oil Co., LTD.), in which glycoside forms of genistein and daidzein are included, and whose molecular structures are similar to estrogen, on circadian rhythm. Soy isoflavone is represented by genistein and daidzein, and soyaflavone HG consists of their glycoside, and thus is easily soluble in water. Application of soyaflavone HG to a culture medium keeping Per2::Luciferase KI Mouse Embryonic Fibroblast (MEF) or mouse liver slices could lengthen the bioluminescence rhythm, and also phase-advance or -delay the bioluminescence rhythm, depending on application time. Oral application to these mice could phase-advance using an in vivo imaging system. These data suggest that soyaflavone HG affects some circadian rhythm periods and phases, and maybe useful for recovery from deficit in circadian rhythm in shift-work.
Soy Protein Research, Japan 16, 73-79, 2013.

Key words : circadian, liver, soy bean, genistein, glycoside
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34-16

The Effects of Soy Isoflavone on Myogenic Differentiation

Masahiro OGAWA and Ryoichi YAMAJI*

Department of Biological Chemistry, Division of Applied Life Sc iences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 599-9853

ABSTRACT
The biological activities of 17β-estradiol (E2) are exerted by two estrogen receptor (ER) isoforms (ERα and ERβ), which are ligand-mediated transcriptional factors. Skeletal muscle is the most abundant tissue in the human body. The two ER isoforms are expressed in skeletal muscle. ERα represses myogenic differentiation by increasing the level of ubiquitin-specific peptidase 19 (USP19). On the other hand, ERβ agonist inhibits the ERα-induced expression of USP19, and consequently represses the ERα-repressed myogenic differentiation. Knockdown of ERβ abolishes the inhibitory effects of ERβ agonist on E2-repressed myogenic differentiation. Soy contains estrogenic compounds such as genistein and daidzein, which activate the transcriptional activities of ERα and ERβ. In this study, we investigated whether daidzein has inhibitory effects on E2-repressed myogenic differentiation. In C2C12 myoblasts, daidzein attenuated the E2-decreased expression of structural muscle proteins (myosin heavy chain and tropomyosin) and E2-increased expression of USP19. However, genistein had no inhibitory effects of E2-repressed myogenic differentiation. When ovariectomized female ddY mice (8 weeks old) were fed diets containing 0.1% isoflavone (genistein or daidzein) with or without E2 replacement, daidzein, but not genistein, inhibited E2-decreased muscle masse and E2-increased expression of USP19 in skeletal muscles. These results suggest that daidzein inhibits USP19 expression by activating ERβ and increases skeletal muscle mass in female mice.
Soy Protein Research, Japan 16, 80-85, 2013.

Key words : isoflavone, daidzein, skeletal muscle, estrogen, ubiquitin-specific peptidase 19
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34-17

Analysis of Lowering Effect of Isoflavones on Fat Tissue Weight, Liver Triglycerides, and Serum Triglycerides Concentration in C3H/HeN Mice

Fumihiko HORIO*

Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601

ABSTRACT
The aim of this study was to investigate the effect of dietary soy isoflavones on fat tissue weights, liver fat accumulation and serum triglyceride concentrations. Male C3H/HeN mice were fed AIN93G diet (AIN group) or AIN93G diet supplemented with 400 ppm soy isoflavones (AIN+ISO group) for 12 weeks. From week 7 to week 12, body weight in the AIN+ISO group was significantly lower than that in the AIN group, but food intake was equivalent in both groups during the course of the experiment. Serum triglyceride concentrations and insulin concentrations were lower in the AIN+ISO group than the respective values in the AIN group. However, the hepatic triglyceride content did not differ between these two groups. Hepatic SREBP-1 mRNA levels and epidydimal fat tissue lipoprote in lipase (LPL) mRNA levels were significantly lower in the AIN+ISO group than the respective values in the AIN group. These results indicate that dietary ad dition of 400 ppm soy isoflavones decreases fat tissue weight, and suggest that dietary soy isoflavones reduce serum triglyceride concentrations via the suppression of fatty acids synthesis in the liver by lowering serum insulin concentrations.
Soy Protein Research, Japan 16, 86-91, 2013.

Key words : Isoflavones, Serum triglycerides concentration, Fat tissue weight, Liver fat
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34-18

Protection of Age-Related Hearing Impairment by Dietary Beta-Conglycinin

Tohru TANIGAWA*1, Rei SHIBATA2 and Hiromi UEDA1

1Department of Otolaryngology, Aichi Medical University, Nagakute 480-1195
2Department of Cardiology, Nagoya University, Nagoya 466-8550

ABSTRACT
We aimed to investigate whether dietary beta-conglycinin could protect against age-related hearing impairment in mice. Six-month-old C57BL/6J male mice were fed diets containing beta-conglycinin (n=6) or casein (n=5) for 6 m onths. Six months after starting these diets, body weights were significantly higher in the casein-fed group than in the beta-conglycinin-fed group (p<0.01). Casein-fed mice exhibited increased auditory brainstem response (ABR) hearing thresholds at all frequencies, whereas beta-conglycinin-fed mice exhibited no increased ABR threshold shifts (<30 dB). The ABR threshold shift was significantly different at 4 kHz (p<0.01) and 32 kHz (p<0.05). Transmission electron microscopic studies revealed that the num ber of lipofuscin granules in spiral ganglion neurons (SGNs) was significantly increased in the casein group compared to that in the beta-conglycinin group (p<0.05). Additionally, morphological damage in the stria vascularis (SV) was more severe in the casein-fed group than in the beta-conglycinin group. Our data suggest that dietary beta- conglycinin could protect against age-related hearing impairment. Six-month-old adiponectin (APN) KO mice showed moderate [>50 dB sound pressure level (SPL)] to severe (>70 dB SPL) hearing losses (in submission). Serum APN was higher in the beta-conglycinin group than in the casein group. These results suggest that increased levels of serum APN in the beta-conglycinin group might afford protection against morphological damage in the SV and SGNs, and, consequently, prevent hearing impairment.
Soy Protein Research, Japan 16, 92-98, 2013.

Key words : soy protein, beta-conglycinin, hearing impairment, obesity, adiponectin
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34-19

Anti-Muscle Atrophy Action of Dietary Soy Proteins

Takeshi NIKAWA*

Department of Nutritional Physiology, Institute of Health Biology, The University of Tokushima Graduate School, Tokushima 770-8503

ABSTRACT
Background: Unloading stress induces skeletal muscle atrophy. We have reported that Cbl-b ubiquitin ligase is a master regulator of unloading-associated muscle atrophy. The present study was designed to elucidate whether dietary soy glycinin protein prevents denervation-mediated muscle atrophy, based on the presence of peptides inhibiting Cbl-b ubiquitin ligase in soy glycinin protein. Methods Mice were fed either 20% casein diet, 20% soy protein isolate diet, 10% glycinin diet containing 10% casein, or 20% glycinin diet. One week later, the right sciatic nerve was cut. The wet weight, cross sectional area (CSA), IGF-1 signaling, and atrogene expression in hindlimb muscles were examined at 1, 3, 3.5, or 4 days after denervation. Results: The 20% soy glycinin diet significantly prevented denervation-induced decreases in muscle wet weight and myofiber CSA. Furthermore, dietary soy protein inhibited denervation-induced ubiquitination and degradation of IRS-1 in the tibialis anterior muscle. Dietary soy glycinin partially suppressed the denervation-mediated expression of atrogenes, such as MAFbx/atrogin-1 and MuRF-1, through the protection of IGF-1 signaling estimated by phosphorylation of Akt-1. Conclusions: Soy glycinin contains a functional inhibitory sequence against muscle-atrophy-associated ubiquitin ligase Cbl-b. Dietary soy glycinin protein significantly prevented muscle atrophy after denervation in mice.
Soy Protein Research, Japan 16, 99-103, 2013.

Key words : Soy Protein, Muscle Atrophy, Ubiquitin Ligase Inhibitor

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34-20

Effects of Soybean Product Intake on Incidence of Type 2 Diabetes, Impaired Insulin Resistance and Impaired Insulin Secretion-the Saku Study

Yukako TATSUMI*1, Akiko MORIMOTO1, Kizyo DEURA2, Yuko OHNO1, Syoichi MIZUNO2 and Shaw WATANABE2,3

1Department of Mathematical Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871
2Saku Central Hospital, Nagano 384-0301
3Life Science Promoting Association, Tokyo 156-8502

ABSTRACT
Aims: To investigate the effects of soybean product intake on incidence of type 2 diabetes mellitus considering fasting and postload hyperglycemia, and change of insulin resistance and insulin secretion. Materials and Methods: This 4-year, cohort study included 1,738 men and 1,301 women, aged 30-69 years, without diabetes mellitus at baseline who underwent comprehensive medical check-ups including a 75 g oral glucose tolerance test (75 g OGTT) between April 2006 and March 2007 at Saku Central Hospital. Participants were stratified by sex and body mass index (BMI), and further classified into three groups based on soybean product intake: Group 1 (0-1 time/wk), Group 2 (2-3 times/wk), and Group 3 (4 or more times/wk). Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs); 95% confidence intervals (CIs) for incidence of type 2 diabetes mellitus, fasting hyperglycemia (fasting plasma glucose ≥ 7.0 mmol/L) and postload hyperglycemia (2-h plasma glucose ≥ 11.0 mmol/L) were estimated. Results: During 10,503 person-years of follow-up, 204 participants developed type 2 diabetes mellitus, including 61 who developed fasting hyperglycemia and 147 who developed postload hyperglycemia. Among men with a high BMI, Group 3 had significantly lower risk for incidence of type 2 diabetes mellitus, fasting hyperglycemia, and postload hyperglycemia than Group 1, and multivariable-adjusted HRs and 95% CIs were 0.44 (0.22-0.89), 0.36 (0.15-0.96), and 0.40 (0.18-0.92), respectively. There were no significant changes in insulin resistance and insulin secretion in either sex. Conclusions: Soybean product intake prevented fasting and postload hyperglycemia and type 2 diabetes mellitus in men with a high BMI.
Soy Protein Research, Japan 16, 104-111, 2013.

Key words : Soybean, Type 2 diabetes mellitus, Postload hyperglycemia, impaired insulin resistance and impaired insulin secretion

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34-21

Effects of Soybean Peptide AM Intake on Muscle Weakness in the Elderly

Shigeru YAMADA*1, Anna TANAKA2, Hitomi FUJITA1 and Aya OZEKI1

1Graduate School of Human Life Science, Jissen Women's University, Tokyo 191-8510
2Faculty of Human Life Sciences, Jissen Women's University, Tokyo 191-8510

ABSTRACT
In several animal experiments, it was found that the soybean peptide AM inhibits skeletal muscle atrophy. Based on these results, we have investigated the effect on skeletal muscle atrophy in humans. We investigated the effect of soybean peptide AM intake in subjects, including elderly women and female college students. In study A, 3 months after soybean peptide AM intake, the skeletal muscle of female college students showed a statistically significant increase. Further, after intake of soybean peptide AM, their BMI value decreased statistically significantly. However, there was no significant difference in the measured value of each item in a physical fitness test. In Study B, about three months after taking the soybean peptide AM, no change was observed in the amount of body fat and skeletal muscle mass in the elderly. However, a statistically significant difference was observed in items of a physical fitness test, particularly the one leg stand eyes-open value. Thus the effect of the intake of soybean peptide AM on the forms and functions of the elderly and college students were found to be different.
Soy Protein Research, Japan 16, 112-118, 2013.

Key words : Soybean peptide AM, female college students, elderly people of 75years old, Skeletal muscle
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34-22

Fabrication of SPI-Starch Complexes for Use as Ingredients - A Pilot Cooking Study

Kyoko OHISHI*1 and Etsuko IMAI2

1Department of Life and Ecology, School of Human Ecology, Wayo Women's University, Ichikawa 272-8533
2Department of Human Nutrition, Faculty of Human Nutrition, Seitoku University, Matsudo 271-8555

ABSTRACT
An SPI gel with no starch and SPI-starch (potato) complexes fabricated by substitution of part of the SPI with starch were prepared. When each preparation was heated in 10% sucrose, the SPI gel swelled with decreases in hardness and cohesiveness, whereas the fabricated gels showed no such changes. Also, heating of the preparations in 1% NaCl caused no appreciable physical changes. Heating in an "umami" stock (glutamate solution) containing a higher concentration of NaCl gave the result that the SPI gel shrank with an increase in hardness, while the physical properties of the fabricated gels remained constant. As to the gels seasoned with NaCl, compared to the SPI gel the fabricated gels distinctly reduced in hardness and cohesiveness without changing to physical properties during heating. The seasonings went into and came out from the fabricated gels more slowly than with the SPI gel. This may reflect the effect of some three-dimensional SPI-starch complex structure. Thus, our research in this pilot study suggests that the fabricated gel we constructed will have practical use in food processing and/or cooking at home.
Soy Protein Research, Japan 16, 119-126, 2013.

Key words : starch, texture, hardness, cohesiveness, cooking
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34-23

Vitamin B6 Status in Rats Fed Soybean Protein Isolate

Yasuka ISA*1, Tomoyuki MISHIMA2, Kohei YAMAMOTO3 and Takashi HAYAKAWA3

1Faculty of Home Economics, Gifu Women's University, Gifu 501-2592
2School of Health Sciences, Gifu University of Medical Science, Seki 501-3892
3United Graduate School of Agricultural Science, Gifu University, Gifu 501-1193

ABSTRACT
The aim of this study was to a comparison Vitamin B6 (B6) nutritional status of rats fed casein or Soy Protein Isolate (SPI). Wistar/ST male rats were fed 20% casein (C group), 60% casein (HC group), 20% SPI (S group) and 60% SPI (HS group) diets for 4 weeks. At weekly intervals, 24 h urine samples were collected for measurement of xanthurenic acid. There was no significant difference in urinary xanthurenic acid excretion among the four groups. At the end of the experiment, blood and liver were obtained. Plasma total B6 concentration in C group and the HC groups was significantly higher than that in the S group and HS groups (p<0.05). Content of hepatic B6 in the high protein diet group was significantly higher than in the low protein diet group (p<0.05). Erythrocyte aspartate and alanine aminotransferase activity (EAST, EALT) with and without PLP showed no significant difference among the four groups. These results suggest that SPI would be needed for B6 in the diet more than casein.
Soy Protein Research, Japan 16, 127-132, 2013.

Key words : vitamin B6, nutritional status, plant protein, soybean
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34-24

Study of the Regulatory Mechanism for Energy Metabolism in Adipocyte by Branched-Chain Amino Acid Metabolism

Tsuyoshi GOTO*1,2, Nobuyuki TAKAHASHI1,2 and Teruo KAWADA1,2

1Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Uji 611-0011
2Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011

ABSTRACT
Dysfunction of obese adipose tissue is one of the main causes of various metabolic disorders, such as diabetes and hyperlipidemia. It is well known that soy proteins have potential health benefit effects on obesity-associated metabolic disorders. Although the molecular mechanisms underlying these effects are not fully understood, the health benefit effects of soy protein on metabolic disorders seem to be, at least partially, due to amino acid composition. In this study, we investigated the effects of amino acids on the functions of adipocytes. At first, we investigated whether the addition of amino acids affects triglyceride accumulation in 3T3-L1 adipocytes, and it was found that the addition of leucine (one of the branched-chain amino acids (BCAAs)) suppressed triglyceride accumulation in 3T 3-L1 cells in insulin non-addition condition. Leucine suppressed 2-deoxy-D-glucose (2-DG) uptake but did not affect lipolytic activity in 3T3-L1 cells. Moreover, mRNA expression levels of genes related to BCAAs catabolism were changed during adipocyte differentiation. In obese KK-Ay mice fed a diet containing leucine (2%) for 3 weeks, blood glucose level and glucose intolerance were improved. These results indicate that leucine intake improves glucose metabolism, and changes in adipocyte functions induced by leucine might contribute to this effect.
Soy Protein Research, Japan 16, 133-137, 2013.

Key words : obesity, adipocyte, BCAAs, amino acids
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34-25

The Association of Peroxisome Proliferator Activated Receptor-Gamma Genetic Variants with Serum Protein Level in Japanese Men

Yasuko SONE1*, Shigenobu EGAWA2, Kazuo KAWAHARA3, Kazuo KONDO4, Yuzuru OTSUKA4 and Yoko FUJIWARA4

1Institute of Environmental Science for Human Life, Ochanomizu University, Tokyo 112-8610
2Fukuoka Institute of Occupational Health, Fukuoka 815-0081
3Department of Health Policy Science, Graduate School of Tokyo Medical and Dental University, Tokyo 113-8549
4Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo 112-8610

ABSTRACT
Background: The association between serum protein level and genetic variants of peroxisome proliferator activated receptor-gamma (PPARγ) genes is unclear. The aim of this study is to elucidate the association with serum protein level and single nucleotide polymorphism (SNP) rs2938392 in the PPARγ gene in middle-aged men. Methods and Results: 140 healthy mail subjects to were recruited, and their serum lipid profiles were measured. The subjects were genotyped for the SNPs rs2938392 in PPARγ gene. Multiple regression analysis was conducted to detect PPARγ genotypes in relation to total protein and albumin level. Subjects carrying the heterozygous genotype for SNP rs2938392 of PPARγ had a lower albumin level. However, the total protein level was not related to the SNP rs2938392 of PPARγ gene. Those having the heterozygous genotype of PPARγ had a risk of lower albumin level. Conclusion: In the Japanese subjects, the PPARγ gene polymorphism was associated with the serum albumin level. Further investigation is necessary to identify the mechanisms directly infl uencing albumin level.
Soy Protein Research, Japan 16, 138-143, 2013.

Key words : Albumin, Japanese population, Peroxisome Proliferator Activated Receptor-Gamma, Single nucleotide polymorphisms, Total protein.
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34-26

Search for the Bioactive Molecule in Soybeans to Improve Visceral Fat Accumulation Through Targeting an Angiotensin-Converting Enzyme

Shiro ITAGAKI*

Department of Pharmacy, School of Medicine & Hospital, Hirosaki University, Hirosaki 036-8563

ABSTRACT
Obesity is considered to be the background for the three main causes of death in Japanese, cancer, cardiac disease and cerebrovascular disease. Obesity prevention is therefore a growing problem in our country. However, a product that can improve visceral fat accumulation has not yet been launched. A dietary approach to ingesting food factors from the diet is important in preventing lifestyle-related diseases, including obesity. In clinical practice, ACE inhibitors or angiotensin receptor blockers are the antihypertensives of choice because they have the most benefi cial effects on overall morbidity and mortality. In addition to hypertension, the use of an ACE inhibitor has been associated with reductions in visceral fat. Angiotensinogen (AGT) is the precursor of angiotensin and is cleaved into angiotensin I and II in the renin-angiotensin system. It has been reported that AGT is present in fat tissue and that AGT produced by adipose tissu e plays a role in local adipose tissue development. These findings suggest that AGT in fat tissue may be the key to the improving effects of ACE inhibitors on visceral fat and maybe a therapeutic target for visceral fat accumulation. The aim of this study is to identify the ACE Inhibitors in soybeans and to elucidate the effect of ACE on the nature of AGT in fat tissue. I have identified an ACE inhibitor (nicotianamine) in soybeans. I found that AGT in fat tissue is composed of four different glycosylated (single, double, triple, and quadruple) AGTs and that quadruple glycosylated AGT is the key to the improving the effects of ACE inhibitors on visceral fat and maybe a therapeutic target.
Soy Protein Research, Japan 16, 144-149, 2013.

Key words : angiotensinogen, angiotensin-converting enzyme, glycosylation, visceral fat accumulation
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34-27

Inhibitory Effects of Isoflavones Derived from Soy Beans on Muscle Atrophy in C2C12 Myotubes

Katsuya HIRASAKA*, Tasuku MAEDA, Marie HARUNA, Shohei KOHNO, Tomoki ABE, Arisa OCHI, Shigetada TESHIMA-KONDO, Ayako OHNO, Yuushi OKUMURA and Takeshi NIKAWA

Department of Nutritional Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503

ABSTRACT
Proinflammatory cytokines contribute to a progression of age-associated muscle atrophy (sarcopenia) caused by ubiquitin-proteasome-dependent proteolysis. Although isoflavones as a potent antioxidative nutrient have been known to reduce muscle damage during the catabolic state, the other effects of isoflavones, but not antioxidants, against on muscle atrophy are not well known. Here we report on the inhibitory effects of isoflavones on muscle atrophy caused by tumor necrosis factor (TNF)-α treatment. In C2C12 myotubes, TNF-α treatment markedly elevated the expression of the muscle-specific ubiquitin ligase MuRF1, but not of atrogin-1, leading to myotube atrophy. We found that MuRF1 promoter activity was mediated by acetylation of p65 that is a subunit of NF-κB, which is the molecule of the TNF-α downstream signaling pathway, while increased MuRF1 promoter activity was abolished by SIRT1, which is associated with the deacetylation of p65. Moreover, isoflavones significantly suppressed MuRF1 promoter activity and myotube atrophy induced by TNF-α in C2C12 myotubes. These results suggest that isoflavones suppress myotube atrophy in skeletal muscle cells through an activation of SIRT1 signaling.
Soy Protein Research, Japan 16, 150-155, 2013.

Key words : muscle atrophy, ubiquitin ligase, isoflavone
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34-28

A Novel Treatment of Anti-Obesity and Diabetes by Targeting Immune Regulation of Soy Isoflavone

Rie TSUTSUMI*, Emi SHUTO, Miku KIOKA and Tohru SAKAI

Department of Public Health and Applied Nutrition, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503

ABSTRACT
Metabolic syndrome is the underlying factor process in critical disorders such as diabetes, diabetes, stroke, etc. Recently it was reported that T cell-infiltrated into adipose tissues regulated differentiation of macrophages, so macrophages cause chronic inflammation in adipose tissue and the whole body. We previously reported the immune function of soy isoflavone. In this study, we examined the effects of equol on inflammation in diet induced-obese mice. Groups of mice were administered to vehicle or equol. The doses of equol used were 20 mg/kg body/day. There was no difference between the two groups in body weight. However, mice administered equol showed a ameliorated lipid metabolism, and a declining trend in accumulation of body fat. In addition, mice administered equol had significantly inhibited expression of gene-associated macrophage. Thus, it is suggested that equol might possibly prevent metabolic syndrome.
Soy Protein Research, Japan 16, 156-161, 2013.

Key words : Inflammation, equol, metabolic syndrome, macrophage
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34-29

Effect of Equol on Rat Skeletal Muscle Properties

Wataru MIZUNOYA*, Kenta SHIMOMURA, Taiki AKASAKA, Mako NAKAMURA, Ryuichi TATSUMI and Yoshihide IKEUCHI

Graduate School of Agriculture, Kyushu University, Fukuoka 812-8581

ABSTRACT
Equol, a soy isoflavone metabolite, is thought to be a candidate as a ligand for nuclear receptors such as estrogen-related receptorγ (ERRγ), which affects skeletal muscle properties. We addressed whether dietary equol administration affects skeletal muscle function and fiber type-related protein expression in rats. Seven-week-old male F344 rats were orally administered a solution with or without equol (10 mg/kg/day) for 5 weeks, then blood and tissue samples were collected. Muscle function was measured two days before sacrifice. Significant differences between the control group and the equol group were not found in muscle function and fiber type-related protein expressions. However, equol existed in plasma at more than 20 μM which could be expected of ligand activity by nuclear receptors, though almost all the equol was in conjugated form. Equol accumulation was detected in skeletal muscle in three out of six rats administered equol. Furthermore, the accumulation tended to be high in electrically stimulated muscles.
Soy Protein Research, Japan 16, 162-168, 2013.

Key words : soy isoflavone, equol, skeletal muscle, fiber type, nuclear receptor
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34-30

The Benefits of Soy-Related Polyphenols in Pancreatic β-Cell Growth

Hiroko HORIUCHI and Naoki HARADA*

Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531

ABSTRACT
Type 2 diabetes mellitus (T2DM) is a serious health problem in developed countries. The loss of balance between insulin secretion and in sulin sensitivity is associated with the development of T2DM. To sustain an adequate pancreatic β-cell mass is important for prevention of T2DM because the decrease of β-cell mass, which is caused by the suppression of proliferation or an increase in cell death, results in impaired insulin secretion. In the present study, we assessed the effects of S-equol, which is enatiospecifically metabolized from the soy isoflavone daidzein, on pancreatic β-cell growth. In INS-1 rat β-cells, S-equol, but not R-equol and daidzein, enhanced the proliferation of INS-1 cells. The estrogen receptor antagonist (ICI 182,780) did not inhibit the S-equol-increased proliferation of INS-1 cells. S-equol suppressed alloxan-induced INS-1 cell death. The protein kinase A signal inhibitor (H89), but not PI3K/Akt signal inhibitor (LY294002), diminished S-equol-induced proliferation and survival in INS-1 cells. These results show that S-equol increased proliferation and survival through activation of protein kinase A signaling.
Soy Protein Research, Japan 16, 169-172, 2013.

Key words : pancreatic β-cells; S -equol; protein kinase A signaling; type 2 diabetes mellitus
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34-31

Basic Study of Soybean Cyst Nematode Control by Enhanced Expression of Soybean Genes

Shin OKAZAKI*

Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu 183-8509

ABSTRACT
The soybean cyst nematode (SCN) is a devastating pathogen that causes approximately 10% production loss and reduces seed yield more than any other soybean pathogen. Reports have shown that it causes as much as 1.5 billion dollars in agronomic losses every year world-wide. In Japan, SCN causes serious damage, especially in Hokkaido and Tohoku. Major approaches to suppress SCN involve crop rotation and green manure cultivation; however, the effectiveness of both approaches is quite limited. In this study, we explored a novel approach to controlling SCN infection using a molecular genetic approach. Soybean genes responsible for SCN resistance were selected by comparative expression analysis of soybean roots grown in SCN-containing and non-containing soils. Disease-resistance protein KR3, SAR regulator protein NIMIN-1 and Polygalacturonase-inhibiting protein were highly expressed in SCN-containing soil and their respective genes were selected as candidates for SCN resistance. Transgenic soybean roots expressing the candidate SCN resistance genes were constructed using Agrobacterium rhizogenes-mediated transformation. Inoculation tests revealed that the transgenic soybean roots expressing Disease resistance-prot ein KR3 have lower levels of SCN infection relative to wild-type soybean roots. Furthermore, plant fresh weights of the KR3-expressing soybeans were increased in comparison to the wild-type soybeans when grown in SNC-containing soil. These results indicate the potential ability of Disease-resistance protein KR3 for breeding SCN-resistant soybeans.
Soy Protein Research, Japan 16, 173-176, 2013.

Key words : cyst nematodes, soybean, gene expression
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34-32

Analysis of Soy Protein Hydration Structure during Coagulation by Perturbation-Correlation Two-Dimensional Near-Infrared Correlation Spectroscopy

Takuma GENKAWA*

Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572

ABSTRACT
In the present study, the hydration structure of soy protein during coagulation was analyzed by using near-infrared (NIR) spectroscopy combined with two-dimensional correlation spectroscopy (2DCOS). Commercial plain soymilk was heated from 20°C to 80°C at 10°C intervals, and cooled to 20°C. During this heating-cooling process, diffuse reflectance NIR spectra and viscosity of the soymilk were acquired every 30 seconds for 30 minutes with a FT-NIR spectrometer and a rotational viscometer. Correlation between the viscosity and the NIR spectrum was expl ored with 2DCOS. The viscosity of soymilk decreased with heating and increased with cooling, and viscosity at 20°C increased 1.4 times before and after the heating-cooling process. In the NIR spectra, bands arising from the OH group showed blue shift. These shifts mean that hydrogen bonding was broken by heating. In the 2D correlation spectra, bands at 5,290 cm -1 (1,890 nm) and 4,900 cm -1 (2,070 nm) were detected, and these bands were assigned to the weakly hydrogen-bonded OH group of water and the NH group of hydrated protein, respectively. Moreover, from the perturbation correlation 2D correlation spectra, it was shown that in the cooling process after heating the band of hydrated protein changed drastically between 50 and 40°C, at which point the viscosity also increased significantly. These results suggest that change in hydration of soybean protein induced change in the viscosity of soymilk.
Soy Protein Research, Japan 16, 177-181, 2013.

Key words : near-infrared spectroscopy, two-dimensional correlation spectroscopy, hydration structure, viscosity, coagulation
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