Improvement in Zinc Nutrition and Memory by Soybean Components
Taiho KAMBE*1 and Atsushi TAKEDA2
1Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502
2Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526
ABSTRACT
Zinc is an essential trace element as a the second most abundant transition metal in biological systems. Zinc plays indispensable roles in a number of physiological processes as a structural, catalytic or signaling factors within protein functions, and thus its deficiency leads to a variety of health problems including in brain functions. Zinc is highly accumulated in synaptic vesicles in the hippocampus, and synaptic
zinc signaling is involved in synaptic plasticity such as long-term potentiation (LTP), and memory. Therefore, increased attention should be paid to preventing systemic zinc deficiency, as well as brain zinc deficiency, in daily life. Zinc is absorbed in the small intestine, which is mediated by the zinc transporter ZIP4. Thus food component(s) that would enable an increase in cell surface ZIP4 expression would lead to increases of cellular zinc levels. Because soyasaponins have such activities, we here examined whether or not soyasaponins rescue amyloid β-mediated impairments of LTP by feeding rats drinking water containing soyasaponins. We also examined whether soyasaponins have antidepressant-like effects in the rats fed them and subjected to the forced swim test. Furthermore, we searched soybean extracts to identify novel soybean component(s) that are active in increasing cell surface ZIP4 expression. These approaches could possibly be a major step in preventing zinc deficiency and improving brain functions.
Soy Protein Research, Japan 21, 1-6, 2018.
Key words : soybean extracts, ZIP4, LTP, depression, zinc
Effects of Dietary Soy Protein and Whey Protein on Denervation-Induced Skeletal Muscle Atrophy (III)
Takeshi NIKAWA*1, Rie HASHIMOTO2, Reiko NAKAO1, Takayuki UCHIDA1, Miyuki NINOMIYA1, Yuki KIMORI1, Ayako MAITA1, Yukari MIKI1, Miyu UCHIDA1, Hiroaki YANAGAWA3 and Koichi SAIRYO4
1Department of Nutritional Physiology, Institute of Medical Nutrition, Tokushima University Graduate School,
2Konan Women's University,
3Tokushima University Hospital, Clinical Trial Center for Developmental Therapeutics,
4Department of Orthopedics, Institute of Medical Sciences, Tokushima University Graduate School
ABSTRACT
Both soy protein and whey protein are reported to be effective in treating muscle atrophy. It is thought that the former inhibits the muscle protein degrading system and the latter stimulates the muscle protein synthesis system. Therefore, in this specific study, the synergistic effect of soy protein and whey protein on muscle atrophy suppression was examined. In 2015, a 20% mixed protein diet with mixed soy protein and whey protein in 1:1 is more resistant to muscle atrophy due to sciatic nerve resection than soy protein or whey protein alone something an
additive inhibitory effect. In 2016, the mixing ratio of soy protein and whey protein was changed and the effect on inhibiting muscle atrophy was compared. As a result, the mixed diet wherein the ratio of soybean protein and whey protein was 1:1 exhibited the strongest muscle atrophy effect. In 2017, the final year of this project, we asked subjects who tended to bedridden patients for a mixed meal with whey protein alone and soy protein to whey protein ratio of 1:1. Unfortunately, only one subject in each group was found, and the results of the process are reported.
Soy Protein Research, Japan 21, 7-10, 2018.
Key words : clinical intervention trial of diet, knee extension muscle strength, regulation for clinical research, whey protein, soy protein
The Clarification of the Molecular Mechanism of the Improvement of Lipid Metabolism by Soybean β-conglycinin Based on a Novel Active Peptide Identification
Satoshi NAGAOKA*1 Toshiro MATSUI2 and Mitsuru SEISHIMA3
1Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193
2Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka 812-8581
3Departments of Informative Clinical Medicine, Gifu University Graduate School of Medicine, Gifu 501-1194
ABSTRACT
We identified for the first time that portal blood plasma contains some peptides (375.2311 m/z, 519.2738 m/z) derived from β-conglycinin after a single oral administration of β-conglycinin in rats. We identified for the first time that the blood plasma contained some peptides (151.8 m/z, 152.7 m/z, 164.5 m/z, 165.5 m/z, 168.6 m/z, 180.8 m/z, 195.6 m/z, 216.8 m/z, 239.9 m/z, 243.7 m/z, 245 m/z, 251.9 m/z, 263.7 m/z, 270 m/z, 276.7 m/z, 278.9 m/z, 282.8 m/z, 298 m/z, 299.9 m/ z, 301.9 m/z, 307.9 m/z, 328 m/z, 342.1 m/z, 358 m/z, 362.8 m/z, 368.1 m/z, 389 m/z, 393 m/z, 1,517.1 m/z) derived from β-conglycinin after a single oral administration of β-conglycinin in humans. We investigated the molecular mechanism of the inhibitory action of cholesterol micellar solubility by VVFLASVS in vitro compared with a drug, cholestyramine, as a positive control. Cholestyramine specifically binded to taurocholate in micelles when cholestyramine inhibited cholesterol micellar solubility in vitro, while VVFLASVS decreased taurocholate, monoolein, oleic acid and phosphatidyl choline concentration in micelles when VVFLASVS inhibited cholesterol micellar solubility in vitro.
Soy Protein Research, Japan 21, 11-16, 2018.
Key words : peptide, beta-conglycinin, bile acid, plasma peptide, VVFLASVS
Impact of Water Soluble Soy Isoflavones on the Murine Gut Microbiome
Sang Eun Kim1, Yuka KAMEI1 and Mitsuo MARUYAMA*1, 2
1Department of Mechanism of Aging, National Center for Geriatrics and Gerontology (NCGG), Obu
2Department of Aging Research, Nagoya University Graduate School of Medicine, Nagoya
ABSTRACT
Water soluble soy isoflavone (Soyaflavone HG; supplied by Fuji Oil Co., Ltd), which contains glycoside forms of isoflavones, could have beneficial effects on inflammation and on such conditions as hypercholesterolemia, atherosclerosis and postmenopausal syndrome. Some recent studies suggest that the beneficial effects in health of soy and soy bioactive components may be regulated by gut microbiota. To better understand this, we tested the effects of Soyaflavone HG on microbial alteration by using Illumina 16S rRNA next generation sequencing. We demonstrated the Illumina 16S rRNA sequencing of fresh fecal samples from C57BL/6N (male, 2-months old) mice with free access to drinking water containing 0.5% of Soyaflavone HG for four weeks. Beta diversity analysis based on principal coordinate analysis (PCoA) shows that Soyaflavone HG treatment could be discriminated at two and four weeks after Soyaflavone HG treatment (2 wk and 4 wk) fecal samples from controls (0 wk, before treatment begins). Bacteroidetes, Firmicutes, Actinobacteria and Proteobacteria constituted the four major dominant phyla in all samples. The proportion of Bacteroidetes and Firmicutes were significantly altered by Soyaflavone HG treatment. A total of 23 genera with proportions above 0.1% were detected in each sample. A total of 3 genera were significantly different between pre (0 wk) and post treatment with Soyaflavone HG (2 wk or 4 wk). The results of this study indicate that gut microbiota might be an important factor for beneficial effects of Soyaflavone HG in gut health and homeostasis.
Soy Protein Research, Japan 21, 17-23, 2018.
Key words : soy isoflavones, murine intestine, microbiome, short chain fatty acids(SCFAs)
Disease Control of Rust Pathogen in Soybean Using Isoflavone
Yasuhiro ISHIGA*1, Md. Zakir HOSSAIN2 and Yuichi YAMAOKA1
1Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572
2Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572
ABSTRACT
Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is a devastating foliar disease affecting soybean production worldwide. Knowing the resistance mechanisms of eight major R genes which mediate resistance to P. pachyrhizi (Rpp) loci is essential for the development of durable varieties. The transcriptomes of susceptible BRS184 and Rpp3 resistance bearing soybean were generated with ASR inoculation (T1-2 isolates, 24 h after inoculation (hai)) and without ASR inoculation (mock). The transcriptome analysis revealed that phenylpropanoid and isoflavonoid pathway-related genes were up-regulated. The relative gene expression study for select genes of that pathway was conducted by RT-qPCR using T1-2 isolates to Rpp1-Rpp4 lines. Generally, Rpp mediated gene resistance is only effective against specific ASR isolates. The RT-qPCR results revealed that the Rpp lines utilized these genes in a rate limiting manner as a defense response. With the exception of glycinol 4-dimethylallyltransferase (G4DT) and chalcone reductase (CHR), all the genes showed the greatest expression at 12 hai, but the gene expressions which occur between 24-96 hai make these Rpp lines unique to their respective ASR isolates. These results clearly indicate that phytoalexin plays an important role in resistance mechanisms of soybeam against P. pachyrhizi.
Soy Protein Research, Japan 21, 24-28, 2018.
Key words : asian soybean rust, soybean, phytoalexin, transcriptome
Pest Control of Soybean Plants using Structure-Modified Menthol Compounds
Gen-ichiro ARIMURA*, Yuna NAKAYAMA, Yoko NONAGA, Satoru SUKEGAWA, Chisato TSUZUKI, Masakazu HACHISU and Shigeomi HORITO
1Department of Biological Science & Technology, Faculty of Industrial Science & Technology, Tokyo University of Science, Tokyo 125-8585
ABSTRACT
“Plant-plant signaling” is a type of natural plant communication in which plants eavesdrop on volatile organic chemicals emitted from neighboring plants to boost their defense responses. A characteristic of mint volatiles has been shown to act as “plant-plant signals” for powerful pest control of agricultural crops, but little is known about their nature and structural variability. In the current study, we therefore explored using a menthol compound with a modification of its residue with a variety of amino acids. Application of the modified menthol compound (compound C) was then found to increase the levels of transcript accumulation of jasmonate- and salicylic acid- signaling-dependent defense genes (trypsin inhibitor (TI) and pathogenesis related 1 (PR1), respectively) in soybean leaves. This pest control system relying on the compound C could be commercially useful for increasing agricultural crop production.
Soy Protein Research, Japan 21, 29-32, 2018.
Key words : herbivore, menthol, mint, plant-plant communications, soybean
Searching for Root Knot Nematode Attractant Peptide from Soybean Root
Takanori IDA*
Center for Animal Disease Control, University of Miyazaki, Miyazaki 889-1692
ABSTRACT
Bioactive peptide plays various important roles as a hormone and a neurotransmitter not only in plants and animals but also in single-celled organisms. We have isolated and identified bioactive peptides from various animal species such as mammals, insects, nematodes, etc. Recently, we discovered that a peptide factor secreted from the roots of soybean attracted the root-knot nematode. Plant infectious nematode damage will exceed 10% of the production amount for soybeans. It seems that nematode countermeasures are indispensable for improving the efficiency of soybean cultivation. Therefore, in this study, we aimed to isolate and identify the root-knot nematode-attracting peptide secreted from this soybean root. There have been no reports that soybean peptides have nematode- attracting activity. Currently, final purification and structural analysis of root-knot nematode-attracting peptide are proceeding. In addition, novel bioactive peptides were discovered from C. elegans, which is useful as a model organism, and the application to root knot nematodes was also examined.
Soy Protein Research, Japan 21, 33-36, 2018.
Key words : nematode, M. incognita, attractant, bioactive peptide
Iron in Soybean Seeds
-Studies of the Biosynthesis and Iron Accumulation Process of Soybean Ferritin-
Taro MASUDA* and Kosuke FUJITA
Laboratory of Food Quality Design and Development, Division of Agronomy and Horticultural Science, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011
ABSTRACT
Iron deficiency is one of the most serious nutritional problems in the world. Because soybean seeds contain a large amount of iron, it is a likely candidate as a sustainable food-derived iron source. It has been suggested that the iron storage protein ferritin may largely contribute to the net iron content in the seed of soybean. Ferritin is a ubiquitous iron storage protein that forms a spherical oligomer composed of 24 subunits. Previously, we have identified four cDNA sequences of soybean ferritin, sfer1-4. In this study, we investigated the whole life of each member of soybean ferritin. The ferritin genes, especially sfer1 and sfer2, were actively expressed during seed maturation, whereas the quantities of sfer3 and sfer4 mRNA were one-tenth less than those of the sfer1 and sfer2. However, all four members were detected as components of soybean ferritin oligomers, although the main components of ferritin were SFER1 and SFER2. The expressions of sfer1, 2 and 3 were induced by the iron overload, while sfer4 showed constitutive expression. The contribution of ferritin iron to a soluble form of iron was 38.7% and 16.4% in seeds and leaves, respectively. Thus, our results quantitatively showed the large contribution of ferritin to the iron content in soybean seeds rather than leaves. In processed foods made from soybean seeds, the oligomeric state of ferritin was variable. However, they also maintained iron, even after severely adverse conditions during food processing.
Soy Protein Research, Japan 21, 37-43, 2018.
Key words : ferritin, iron content, oligomer, subunit, elementary analysis
Development of Practical Soybean-Based Raw Food Material
-Isoflavone-Containing Gluten Free Bread-
Hiroyuki YANO*
Food Research Institute, National Agriculture and Food Research Organization, Tsukuba 305-8642
ABSTRACT
Soya isoflavones have several health benefits, so processed food that allows a moderate daily intake of isoflavones will be highly useful. In this research, we sought to develop isoflavone-containing gluten-free rice bread. When soy flour was added to a rice batter, the specific volume (mL/g) of the bread reduced markedly from 4 mL/g. On the other hand, the bread’s specific volume was not reduced when 1-2% (w/w) of crude extract of isoflavones was added to rice batter. Moreover, neither the appearance nor the flavor was spoiled. The bread had 0.15% (w/w) of isoflavones and 0.089% of agricones. One slice of the bread (50-60 g) is estimated to contain 44.5-53.4 mg of agricones, which exceeds the recommended daily allowance. The bread is made of rice flour, water, yeast, salt, sugar, oil and isoflavones. Also, it can be made easily with a bread-making machine. In conclusion, the practical study presented here will help improve the health benefits of bread.
Soy Protein Research, Japan 21, 44-47, 2018.
Key words : bread, gluten-free, isoflavone, recommended daily allowance
Research on the Mechanism of Soy Protein Emulsion and Its Application to Spread Food
Nobuko EGI*1, Rieko HIROSE2, Kazuko HIRAO1 and Kyoko SAIO1
1Aikoku Gakuen Junior College, Tokyo 133-8585
2Ex Researcher of Tokyo Metropolitan Food Technology Research Center, Tokyo 190-0013
ABSTRACT
The SDS-PAGE patterns obtained by hydrolyzing Fuji Pro F (Fuji Oil Co., Ltd.) with pepsin or papain showed patterns in which the high molecular weight fraction (7S and 11S subunits) decreased and the low molecular weight fraction increased. These SDS-PAGE patterns were similar to those of Proleena 800 (Fuji Oil Co., Ltd.). When vinegar was added to these soybean oil emulsions, the product obtained bonded well with water and had a high stability. Furthermore, by adding Soyafibe (Fuji Oil Co., Ltd.) or sugar to the soybean oil emulsions above, a higher stability was obtained as compared to emulsions without Soyafibe or sugar. Observation under a scanning electron microscope showed a structure in which many soybean oil droplets were dispersed within the protein aggregate, for both emulsions, with or without Soyafibe or sugar. Due to Soyafibe soy protein emulsion not being sweet, its usage as an ingredient in spreads was affirmed.
Soy Protein Research, Japan 21, 48-53, 2018.
Key words : soybean protein emulsion, SDS-PAGE, scanning electron microscope, papain and pepsin, spread foods
Peptide Array-Based Screening to Identify Rosmarinic Acid-Binding Peptides
Keisuke ITO*
School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka 422-8526
ABSTRACT
Many functional food components such as polyphenols confer an unpleasant bitter or astringent taste for humans. It is important to improve the taste of functional food ingredients to take advantage of their health benefits in daily life. In this study, we focused on astringent taste-masking peptides, which inhibit the interaction between rosmarinic acid and the tongue by forming complexes. Physicochemical analysis using the taste sensing system (TS-5000Z) showed that soy protein hydrolyzates reduced the astringent taste signal of rosmarinic acid in a concentration-dependent manner. The mechanism of the taste-sensing system is based on the detection of physicochemical interaction between tastants and artificial lipid-membrane sensors. Therefore, we assumed that any ingredient, for example, peptides present in the hydrolyzates, inhibited the interaction of rosmarinic acid with the sensor by forming a complex with rosmarinic acid. Peptide array technology serves as a functional peptide analysis tool that synthesizes any peptide on a cellulose membrane. From the amino acid sequence of β-conglycinin, several rosmarinic acid- binding peptides were discovered by using peptide array. The binding mechanisms of rosmarinic acid-binding peptides were elucidated through deletion analysis and alanine-scanning analysis. In most cases, the interaction between the basic amino acid residues of the peptides and rosmarinic acid was required for the binding.
Soy Protein Research, Japan 21, 54-58, 2018.
Key words : rosmarinic acid, astringent taste, binding peptides, peptide array, β-conglycinin
The Effects on Fish Growth Performance of Fish Meal Replacement by Pre-Digested Soybean Meal Produced by Fish Waste
Minoru KIHARA*
Department of Marine Biology and Sciences, School of Biological Sciences, Tokai University, Sapporo 005-8601
ABSTRACT
The efficacy of pre-digested soybean meal (PDSBM) as a fish meal substitute in fish feeds was investigated. Crude enzyme solutions for soybean meal (SBM) digestion were prepared from stomach and pyloric caeca obtained from the waste of farmed bluefin tuna viscera, and the enzyme solutions were used to prepare gastric enzyme-digested SBM (G-PDSBM), pyloric enzyme-digested SBM (P-PDSBM) and pyloric enzyme-digested G-PDSBM (GP-PDSBM). Each PDSBM had a mixture of soy sauce and crustacean odors, and as a headspace analysis detected the presence of aldehydes and pyrazines in PDSBM, the odor is likely the product of a Maillard reaction. The feeding activity of salmon on PDSBM prepared with gastric enzyme was higher than that of salmon on SBM, and an improvement of palatability of PDSBM was confirmed by the digestion. Conversely, the feeding activity of jacopever (kurosoi rockfish) on PDSBM prepared with gastric enzymes was lower than that on SBM, suggesting that the response of fish to PDSBM probably differs among species. Finally, the growth coefficient of flounder and jacopever on a P-PDSBM diet was higher than that on an SBM diet. These findings suggest that P-PDSBM could be used as an alternative source of fish meal.
Soy Protein Research, Japan 21, 59-64, 2018.
Key words : bluefin tuna Thunnus orientalis, feeding activity, fish meal substitution, pyloric caeca, pre-digested soybean meal
Subchronic Administration of Soy Peptides Differentially Modulates Central Catecholamine Metabolism in Young Adult and Aged Mice
Saki MATSUMOTO1, Yukako HINO1, Ayumi KOYANAGI1, Waka FURUSAWA1 and Shigeki FURUYA*1, 2
1Laboratory of Functional Genomics and Metabolism, Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences,
2Innovative-Bioarchitecture Center, Kyushu University, Fukuoka 819-0395
ABSTRACT
The effects of subchronic administration of soy peptides on the metabolism of monoamine neurotransmitters in the brains of young adult (9 weeks old) and aged (70 weeks old) mice were examined in C57BL/6 mice. Soy peptide mixture Hinute-AM (66 mg/0.6 mL/30 g body weight) was given to mice orally via gavage for 17 consecutive days. Noradrenaline and its metabolites 3-methoxy-4- hydroxyphenylethyleneglycol (MHPG) and normetanephrine (NM) were determined in the cerebral cortex, brainstem, and hippocampus 24 hours after the last administration. The subchronic administration led to an effective augmentation of MHPG in the brainstem and significant facilitation of noradrenergic turnover in the cerebral cortex of young adult mice compared to vehicle control, while these effects by soy peptides were not observed in any brain regions of aged mice examined. These results indicate that consecutive ingestion of soy peptides leads to activation of noradrenaline metabolism at least in the young adult brain, which may contribute to maintenance of brain health. However, these responses appear to diminish in the aged brain, suggesting that functional changes in the transport system or metabolic processes for food-derived peptides occur due to aging.
Soy Protein Research, Japan 21, 65-70, 2018.
Key words : soy peptide, catecholamine, noradrenaline, brain
Host-Defense Activities and Mechanism of Actions of Cationic Peptides from Hydrolysates of Soybean Proteins
Masayuki TANIGUCHI*
Department of Materials Science and Technology, Niigata University, Niigata 950-2181
ABSTRACT
In this study, we used hydrolysates of soybean proteins as crude peptide samples and generated 20 fractions containing multifunctional cationic peptides with varying isoelectric point (pI) values using ampholyte-free isoelectric focusing (autofocusing). Subsequently, we determined antimicrobial activities of each fraction against the pathogens Prophyromonas gingivalis, Propionibacterium acnes, and Candida albicans. Fractions 19 and 20 had pI values greater than 9 and exhibited antimicrobial activity against P. gingivalis, and P. acnes, but not against C. albicans. In further experiments, we purified and identified cationic peptides from fractions 19 and 20 using reversed-phase high-performance liquid chromatography and matrix-assisted laser/desorption ionization-time-of-flight mass spectroscopy. We also chemically synthesized seven identified peptides (NKN, PGK, NVS, LPC, KSG, KHG, and RKV) with pI values greater than 9.5 and evaluated antimicrobial, lipopolysaccharide (LPS)-neutralizing, and angiogenic activities. Among these synthetic peptides, only LPC exhibited antimicrobial activity against P. gingivalis. However, all seven cationic peptides exhibited LPS-neutralizing activities with little or no hemolytic activity against mammalian red blood cells at functional concentrations. Furthermore, among the seven cationic peptides, four induced angiogenesis of endothelial cells. These present data show dual or multiple functions of the seven identified cationic peptides with little or no hemolytic activity. Therefore, fractions containing cationic peptides from hydrolysates of soybean proteins have the potential to be used as dietary supplements and functional ingredients in food products.
Soy Protein Research, Japan 21, 71-76, 2018.
Key words : cationic peptide, soybean protein, antimicrobial activity, LPS-neutralizing activity, angiogenic activity.
Chrono-Nutritional Effect of Soy Protein Isolate on Lipid Metabolism
Katsutaka OISHI*
Biological Clock Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566
ABSTRACT
Chrononutrition is the science of nutrition based on chronobiology. Numerous epidemiological studies have shown that soy protein reduces the risk of cardiovascular events through various actions such as lowering cholesterol. The present study aimed to determine the time of day when the anti-obesity ability of soy protein isolate (SPI) is optimal in mice. A casein-containing diet was replaced with a diet containing SPI at different times of day for 28 days as described below. Leptin-deficient ob/ob mice were fed with casein diet alone (CTRL) or with SPI- containing diet for 12 hours around the time of activity onset (breakfast (BF)- SPI), or offset (dinner (DN)-SPI). Liver concentrations of free fatty acid and total cholesterol tended to be reduced in both BF-SPI and DN-SPI mice compared with those in CTRL mice. The expression levels of genes associated with fatty acid synthesis such as Fasn, Acaca and Scd1 and cholesterol synthesis such as Hmgcr and Hmgcs1 in the liver were significantly higher in BF-SPI than in DN-SPI mice. Significantly more cholesterol was excreted in the feces of DN-SPI mice than of BF-SPI mice. These findings suggest that dietary SPI induces more hypolipidemic activity at the time of dinner than breakfast, because the intestinal absorption of lipids is more effectively suppressed at that time.
Soy Protein Research, Japan 21, 77-82, 2018.
Key words : circadian rhythm, chrono-nutrition, obesity, cholesterol, soy protein isolate
Effects of Soy Protein and Uremic Toxin on Cardiorenal Syndrome
Ken-ichi MIYAMOTO*, Sawako TATSUMI, Ichiro KANEKO and Hiroko SEGAWA
Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503
ABSTRACT
Chronic kidney disease (CKD) is associated with increased risks of cardiovascular morbidity and mortality. Cardiac remodeling including myocardial fibrosis and hypertrophy is frequently observed in CKD patients. In this study, we investigate the effect of dietary protein-dependent uremic toxin on cardiac hypertrophy associated with CKD using a rat model, by morphological and chemical component changes of the hypertrophic and non-hypertrophic hearts. In addition, we made a comparison of different protein sources (casein and soy protein). Sprague Dawley rats were 4/5 nephrectomized (Nx) at 11 weeks of age and assigned to no treatment or treatment with AST-120 (oral adsorbent) at 18 weeks of age. At 26 weeks of age, the rats were euthanized under anesthesia, and biochemical tests as well as analysis of cardiac condition by histological and spectrophotometric methods were conducted. Cardiac hypertrophy and CKD were observed in 4/5 Nx rats even though vascular calcification and myocardial fibrosis were not detected. The increasing myocardial protein was confirmed in hypertrophic hearts by infrared spectroscopy. Infrared spectra also showed that lipid accumulation was also detected in hypertrophic heart. The lipid associated absorption was also decreased in non-hypertrophic heart. In contrast, soy-protein feeding did not suppress cardiac hypertrophy. We suggest that cardiac remodeling associated with relatively early- stage CKD may be suppressed by reducing increased myocardial protein and ameliorating cardiac lipid load. This suggests a possibility that high serum levels of some uremic toxins and lipid accumulation may be involved in mechanisms of cardiac remodeling. In addition, differences in protein sources (casein and soy protein) did not affect cardiac hypertrophy.
Soy Protein Research, Japan 21, 83-89, 2018.
Key words : chronic kidney disease, cardiovascular disease, inorganic phosphate, lipid, soy protein
Investigating the Effect of Soy Isoflavones on Improving Polycystic Ovary Syndrome Hallmarks
Liyanage GEETHIKA and Shinji OKADA*
ILSI Japan-Endowed Chair of Functional Food Science and Nutrigenomics, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657
ABSTRACT
Women with Polycystic Ovary Syndrome (PCOS), a common endocrine disease during their reproductive age, are currently treated with lifestyle modifications and various medications. Some of these methods are proven to have side effects. Soy isoflavones are a type of phytoestrogens that are extensively studied for their potential health benefits. Recently, the association between gut microbiota and PCOS was also discovered. However, limited studies have been done to examine the effect of soy isoflavones on PCOS hallmarks. In the present study, 7 weeks old female SD rats were divided into 3 groups; Control, PCOS and PCOS+Soy Isoflavones (n = 8/group). The PCOS and PCOS+Soy groups were treated by oral administration of Letrozole at a concentration of 0.5 mg/kg body weight for 21 days to develop a moderate PCOS model. The PCOS+Soy group then received a diet with 0.05% isoflavones for 14 days. The PCOS group showed abnormal estrous cycles and multiple large cysts. After isoflavone treatment, the number of cysts was reduced and the estrous cyclicity was improved in the PCOS+Soy group. As for gut microbiota, Granulicatella and rc4-4 levels were higher in PCOS rats compared to Control ones. When treated with isoflavones the Granulicatella level was reduced in the PCOS group. Collectively, these results suggested that soy isoflavones improved PCOS hallmarks by modulating the gut microbiota.
Soy Protein Research, Japan 21, 90-94, 2018.
Key words : soy isoflavones, PCOS, gut microbiota, polycystic ovary syndrome hallmarks
Inhibition of Demyelination in the Hippocampus by Soy Isoflavone Genistein in Mice Received Exposure of Cuprizone, an Animal Model of Schizophrenia
Tomohiro OHGOMORI and Shozo JINNO*
Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582
ABSTRACT
Recent functional neuroimaging analyses suggest that myelin inflammation in the white matter may play a critical role in the pathogenesis of schizophrenia. Given that estrogen exerts an anti-inflammatory action, some studies have reported the clinical and preclinical benefits of estradiol as an adjunctive treatment of schizophrenia. To further address this issue, here we examined the potential effects of phytoestrogen (plant-derived estrogen), genistein, on the myelin, oligodendrocyte and microglia in the hippocampus of mice fed with diet containing cuprizone, a neuroinflammation model of schizophrenia. The optical disector analysis showed that neither cuprizone-containing diet nor genistein administration affected the spatial distributions of oligodendrocyte precursor cells and oligodendrocytes in the CA1 region. The immunostaining of myelin in the stratum lacunosum- moleculare of the CA1 region was decreased in cuprizone-fed mice and restored by genistein administration. The immunostaining of keratan sulfate, a marker of activated microglia, was increased in the CA1 region of cuprizone-fed mice, and it was restored by genistein administration. The real time polymerase chain reaction showed that the gene expressions of proinflammatory cytokine, IL-1β, and phagocytic marker, CD68, were elevated in microglia of cuprizone-fed mice and restored by genistein administration. Neither cuprizone-containing diet nor genistein administration affected the microglial contact with synaptic terminals. However, microglial contact with myelin was increased in cuprizone-fed mice and restored by genistein administration. The present findings indicate that anti-inflammatory effect of genistein may underlie recovery of myelin in the hippocampus of schizophrenia model via suppression of proinflammatory microglia.
Soy Protein Research, Japan 21, 95-103, 2018.
Key words : hippocampus, cuprizone, myelin, microglia, schizophrenia
Involvement of MicroRNA-Mediated Gene Expression in the Inhibitory Effect of Isoflavone on Bone Destruction
Hirofumi TACHIBANA*1, I-Chian LIN1 and Shuya YAMASHITA2
1Division of Applied Biological Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395
2Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Kagoshima 898-0087
ABSTRACT
MicroRNAs (miRNAs), the small noncoding RNA molecules, regulate gene expressions controlling diverse cell signaling pathways by binding to target mRNAs in order to suppress their translation or promote their degradation. Although miRNAs play a crucial role in many biological processes, including homeostasis and diseases, the relationship between physiological effects of food factors and miRNAs has been mostly unclear. In the present study, we investigated miRNAs taking part in the inhibitory effects of equol, a soy isoflavone metabolite, on rheumatoid arthritis (RA). The collagen-induced arthritis (CIA) mice, a mouse model for RA, were orally administered equol or vehicle, and clinical arthritis scores and bone mineral density were evaluated. The severity of arthritis and the CIA-induced bone destruction were milder in the equol-administered CIA mice than in the control CIA mice. In the inflamed area of CIA mice, equol administration suppressed the gene expressions of interleukin-6 (IL-6) and its receptor IL-6R. Equol also reduced the expression of genes associated with bone destruction, suggesting that equol blocks the IL-6 signaling to suppress the severity of arthritis and inflammatory bone destruction in mice. Equol treatment reduced the gene and protein expression of IL-6R in RAW264.7 cells. We found that the protein level of IL-6R was decreased in miR-320-transfected RAW264.7 cells, indicating that IL-6R is a target of miR- 320. Furthermore, miR-320 expression was up-regulated in equol-treated RAW264.7 cells. These results suggest that equol suppresses the IL-6R expression via the increased expression of miR-320.
Soy Protein Research, Japan 21, 104-109, 2018.
Key words : isoflavone, rheumatoid arthritis, bone destruction, microRNA
Recognition of Soybean Components by Natto-Fermenting Bacillus subtilis
Haruka SUGIURA1, Bunzo MIKAMI2, Kousaku MURATA3 and Wataru HASHIMOTO*1
1Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011
2Laboratory of Applied Structural Biology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 611-0011
3Laboratory of Food Microbiology, Department of Life Science, Faculty of Science and Engineering, Setsunan University, Osaka 572-8508
ABSTRACT
Natto, a traditional Japanese fermented food, is produced from soybean by a saprophytic bacterium Bacillus subtilis. Here, we show the mode of action in the interaction between soybean and B. subtilis. Distinct from naturally dead soybeans, live soybeans with a germination ability significantly inhibited the bacterial growth, suggesting that live soybeans synthesize an antimicrobial agent in response to B. subtilis cells. In the case of boiled dead soybeans, the surface of the soybeans after the bacterial inoculation was covered with a large number of bacterial cells and mucoid molecules were produced on the soybeans. To clarify the B. subtilis genes responsible for the initial response to boiled soybeans, mRNA expression in the bacterial cells grown on soybeans was compared through RNA sequence analysis to that of cells grown on Luria-Bertani medium solidified with agar. The expression of 93 genes out of a total of 4,271 assigned on the basis of the complete genome sequence of B. subtilis BEST195 was up-regulated over 10-fold in soybean-grown cells. Among up-regulated genes, genes crucial for degradation and import of plant cell wall polysaccharides such as pectin and arabinogalactan were significantly expressed in the bacterial cells. The bacterial protein YesO encoded by the up-regulated gene was functionally and structurally characterized. The purified recombinant YesO exhibited an affinity with oligosaccharides generated from rhamnogalacturonan, a component of pectin. X-ray crystallography indicated a binding mode of YesO to oligosaccharides from plant cell walls. This study demonstrated the initial responses both of live soybeans to B. subtilis cells and of the bacterial cells to dead soybeans.
Soy Protein Research, Japan 21, 110-114, 2018.
Key words : Bacillus subtilis, germination, natto, rhamnogalacturonan, soybean
Effect of Water Soluble Soybean Fiber on Intestinal Homeostasis
Takuya SUZUKI*
Food Science and Biofunctions Division, Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima 739-8528
ABSTRACT
The present study examined the intestinal sensory mechanism of and the regulation of intestinal homeostasis by water-soluble soybean fiber (WSSF) using cultured cells and mice. WSSF exhibited the ligand activity for TLR-2 in HEK- Blue reporter cells, indicated by increased alkaline phosphatase production. TNF-α induced inflammatory signaling and IL-8 production in human intestinal Caco-2 cells, whereas the pre-treatment of cells with WSSF suppressed these inflammatory responses in a dose-dependent manner. Increased SOCS-1 via TLR-2 activation seems to be involved in the WSSF-mediated reduction of the TNF-α-induced IL-8 production. In contract, supplementation with WSSF promoted DSS-induced colitis in mice, indicated by reduced body weight and increased colitis score. Immunoblot analysis revealed that the WSSF supplementation as well as DSS administration decreased TJ protein expression in the colon of mice, indicating impaired intestinal barrier function. Acetate, propionate, butyrate and succinate in the feces of mice fed WSSF were higher than those in control mice. Taken together, WSSF directly suppresses the TNF-α-induced inflammatory response via TLR-2 activation in intestinal epithelial cells. Whereas, the excessive production of organic acids through the microbial metabolism of WSSF, possibly resulting in luminal acidification, may be involved in the impaired TJ barrier in the colon of mice. The impaired TJ barrier at least in part contributes to the WSSF-induced promotion of colitic symptoms.
Soy Protein Research, Japan 21, 115-121, 2018.
Key words : water-soluble soybean fiber, intestinal inflammation, intestinal barrier, toll-like receptor-2, suppressor of cytokine signaling-1
Clarification of Improvement in the Mechanism of Magnesium Deficiency by Soybean Components towards Prevention of Hypertension
Akira IKARI*
Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, Gifu 501-1196
ABSTRACT
Magnesium is an essential mineral and cofactor for over 300 enzymes involved in biological processes. A deficiency of magnesium may cause lifestyle-related diseases including hypertension and heart disease. The magnesium balance of the whole body is regulated by absorption from the intestine and excretion from the kidney. Dietary magnesium ion (Mg2+) is absorbed via transcellular and paracellular pathways in the intestinal epithelial cells. Mg2+ transport systems including transient receptor potential melastatin 6 (TRPM6) and cyclin M4 (CNNM4) must be involved in the Mg2+ influx and efflux in the epithelial cells, respectively. However, the regulatory mechanism of expression has not been clarified in detail. Here, we examined the effects of soybean components including genistein, cyanidin, and linoreic acid, and found that cyanidin increased the expression of these Mg2+ transporters in mouse intestinal MCE301 cells. Cyanidin increased the nuclear localization of the peroxisome proliferator-activated receptor α (PPAR α), the binding of PPARα to promoter regions of TRPM6 and the CNNM4, and the promoter activity of TRPM6, which were inhibited by GW6471, a PPARα antagonist. The cyanidin-induced elevation of mRNA levels of TRPM6 and CNNM4 was inhibited by GW6471, but not by GW9662, a PPARγ antagonist. The cyanidin- induced elevation of influx and efflux of Mg2+ in MCE301 cells was also inhibited by GW6471, suggesting that TRPM6 and CNNM4 are functionally expressed in the cells. Taken together, we found that cyanidin increased the expression and Mg2+ transport of TRPM6 and CNNM4 in the mouse intestinal cells. Dietary intake of cyanidin-rich foods may prevent chronic magnesium deficiency and its related diseases.
Soy Protein Research, Japan 21, 122-127, 2018.
Key words : CNNM4, Mg2+ absorption, PPARα, TRPM6
Soy Intake and Diabetes: Epidemiological Studies among Adults and Children
Keiko WADA*, Kie KONISHI and Chisato NAGATA
Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu 501-1194
ABSTRACT
Experimental studies suggest that soy intake plays a protective role in the development of diabetes. However, in epidemiological studies, the association between soy intake and diabetes is inconclusive. We evaluated the associations of soy food, soy protein and isoflavone intakes with diabetes incidence in a population- based prospective study in Japan. A total of 31,552 participants aged 35 years over were enrolled in 1992. Soy food, soy protein and isoflavone intakes were assessed via a validated food-frequency questionnaire, while controlling for total energy intake. Ten years after later, a follow-up survey seeking information on diabetes was conducted among 26,546 subjects. The participants who reported diabetes between the time of the baseline study and at the time of follow-up were defined as having diabetes. Using Cox proportional-hazard model, the risks of developing diabetes were calculated according to the intakes of soy food, soy protein and isoflavone, respectively. Analyses were conducted among 6,210 men and 8,096 women. During the follow-up, 288 men and 187 women had developed diabetes. After adjustments for multiple confounders, we found a statistically significant inverse association of soy foods, soy protein, and isoflavones intake with the risk of diabetes in women, but not in men. These results suggest that higher soy intake has a protective effect against diabetes in women. Further research is needed to evaluate this association.
Soy Protein Research, Japan 21, 128-131, 2018.
Key words : soy, soy protein, isoflavone, diabetes, epidemiology
Development of Teaching Materials to Encourage Systematic Understanding of Protein Related Terms
Nami FUKUTOME*1 and Saiko IKEDA2
1Faculty of Health & Nutrition, Tokyo Seiei College, Tokyo 124-8530
2Department of Nutritional Sciences, Nagoya University of Arts and Sciences, Aichi 470-0196
ABSTRACT
While many terms relating to proteins, such as amino acids, can be found in elementary, junior high and high school textbooks, it is not clear that a typical college student has a good understanding of and can recognize such protein related terms. Because proteins play such an important role in the human body, we decided to develop prototype teaching materials focused on terms that are difficult to master but that should be part of a basic understanding of protein by the completion of secondary education. This paper shows how protein related terms are currently dealt with in textbooks and reports on the process of creating prototype teaching materials, which were developed based on the results of a survey on the degree of recognition of the terms among college students. First, we noted among protein related terms in home economics and science textbooks used at elementary, junior high and high schools, we identified a sharp increase in new terms, especially with regards to foreign notation of substance names in high school textbooks. Next, we examined the level of recognition of protein related terms among university students in both nutrition and non-nutrition majors, and we found that the terms could be divided into four word groups. Finally, we experimented with the development of prototype teaching materials using infographic techniques, focusing on terms for which the non-nutrition major students had low awareness.
Soy Protein Research, Japan 21, 132-135, 2018.
Key words : protein related terms, textbook, educational materials, infographics
Proposal of New Food Culture for Japanese Using Tempeh
Sumiko KAMOSHITA1, Indri Kartiko Sari1, Diah Mulyawati Utari1,2 and Shigeru YAMAMOTO1
1Asian Nutrition and Food Culture Research Center, Jumonji University, Saitama 352-8510
2Public Health Nutrition Laboratory, Faculty of Public Health, University of Indonesia, Jakarta
ABSTRACT
Tempeh has no sticky or strong smell like natto, taste is fantastic, and there is no habit, so it can be adapted to various dishes. Tempeh has a dietary fiber content of 10.2 g / 100 g, which is considerably higher than 6.7 g / 100 g of natto. We expanded the utilization of Tempeh and examined the taste to be a new healthy food culture of the Japanese. Subjects were college students, faculty staff, security guards, and cleaners. The cuisine consisted of 10 types of good reputation repeating preliminary research. At the same time, we cooked foods cooked with commonly used ingredients (control) and those cooked at Tempeh (Tempeh utilizing food). Subjects tasted them as lunch and conducted comparative surveys of taste. The evaluation score was 4 points (delicious), 3 points (good), 2 points (not very tasty), 1 point (not tasty). Evaluation of taste was based on 3 points (good). With 10 kinds of dishes, Tempeh utilization cuisine exceeded the standard, and women tended to feel that Tempeh-utilizing cuisine was more delicious than men. Also, I found that there is an application form suitable for Tempeh. In terms of the total amount of dietary fiber, it was found that cooking using Tempeh was about 2 g more than the control, and it is desirable as a new nutritional method of ingesting dietary fiber from main dishes. In this study, we examined whether Tempeh with low awareness meets the taste of Japanese or not by comparing with the control. As a result, the fact that the evaluation close to the control in Tempeh was obtained suggests that Tempeh can be incorporated into Japanese diet.
Soy Protein Research, Japan 21, 136-139, 2018.
Key words : tempeh, fiber, Japanese food culture
Effect of Soy Protein on Aging and Glucose Tolerance in Senescence-Accelerated Prone Mice
Masaru OCHIAI*
School of Veterinary Medicine, Kitasato University, Aomori 034-8628
ABSTRACT
The average life span of people in Japan is the highest in the world, and one of the reasons is "food". Consumption of soy in Japan is higher than that in other countries, and soy proteins are well used in functional processed foods to prevent diet-induced obesity and type-2 diabetes mellitus because soy proteins improve fat metabolism. However, it is not well known whether soy proteins show anti-aging effects. In the present study, we investigated the dietary effects of soy protein and its hydrolysates on muscle mass, glucose tolerance, and endurance capacity in mice. Male senescence-accelerated prone mice (SAMP8) aged 5 weeks were fed with an AIN-93G based casein (C) diet, soy protein (SP) diet, or soy protein hydrolysate (SPH) diet for 3, 6, or 9 months. Food intake and body weight were monitored once a week. Endurance capacity and glucose tolerance were determined, and then plasma, tissues, and carcass were stored for biochemical analyses. Food intake was not different among the groups in any period, but body weight gain was suppressed in the SP and SPH diet groups at the 6 or 9 month periods. Muscle mass and carcass protein rate were higher and adipose tissues weight was lower in the SP and SPH diet groups than those in the C diet group. Glucose tolerance was improved by the SP diet at the three month period and by the SPH diet at the 9 month period. Endurance capacity was improved by the SPH diet. These results indicate that SP and SPH are functional food materials to prevent aging-induced body change and glucose tolerance as well as food materials to improve fat metabolism.
Soy Protein Research, Japan 21, 140-145, 2018.
Key words : soy protein; soy protein hydrolysate, aging, endurance capacity, glucose tolerance; SAMP8
Expression Analysis of Attractant Responsive Genes in Soybean Cyst Nematode
Shinsaku ITO*
Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502
ABSTRACT
Soybean cyst nematode (SCN), a plant parasite, is one of the most serious pests of soybean. Although SCN is attracted to the host root, the attraction mechanism has not been determined. In addition, we recently screened for attractants for SCN, and found nitrate and its analogs. In this study, to analyze the attraction mechanism of SCN, we performed RNAseq analysis with SCN in the process of attraction to nitrate and soybean root. We found that the expression levels of the genes that are involved in infection of the host root and chemotaxis are changed in SCN in the process of attraction.
Soy Protein Research, Japan 21, 146-149, 2018.
Key words : soybean cyst nematode, 1,10-phenanthroline, nitrate, RNAseq
Study of the Roles of Lipid in Protein Aggregation in Frozen Soy Bean Curds during Storage Under Subzero Temperatures
Rika KOBAYASHI*
College of Bioresource Science, Nihon University, Kanagawa 252-0880
ABSTRACT
In order to investigate the effect of lipid on protein aggregation behavior in frozen tofu during storage under subzero temperatures, the texture of three kinds of tofu at selected periods of time during frozen storage at -5°C for 14 days was measured as an index of the protein aggregation behavior. Three kind of tofu used in this study were prepared with a 100% normal soy (control, NS), a 100% Lipoxygenase defective soy (LDS), and a mixed soy like a 50% normal soy and a 50% Lipoxygenase defective soy (MIX), in order to vary the degree of lipid oxidation in tofu before frozen storage. Furthermore, the changing behavior of syneresis, ice crystal and lipid dispersion state in tofu matrix was measured. As a result, the toughness of tofu and the degree of syneresis after frozen storage were high in the order of LDS, MIX, NS, respectively. In addition, a relationship between the changing behavior of texture and the ripening behavior of ice crystals and of lipid droplets was not observed. Summarizing the result, the effect of lipid character on texture changes was not seen to a significant degree.
Soy Protein Research, Japan 21, 150-154, 2018.
Key words : tofu, frozen storage, lipid, ice crystals. texture changes
Effects of Soy Components on the Enzymatic Activity of PKM2
Kenji KOJIMA*
Laboratory of Enzyme Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502
ABSTRACT
Pyruvate kinase (PK) is the enzyme that catalyzes the conversion of phosphoenolpyruvate and adenosine 5'-diphosphate to pyruvate and adenosine 5'-triphosphate at the final step in glycolysis. Tumor cells show an altered metabolic phenotype and convert large amounts of glucose to lactate. In contrast to the exclusive expression of the M1 isoform of PK in normal cells, cancer cells overexpress the M2 isoform (PKM2), which is thought to be related to the characteristic metabolic phenotype of tumor cells. Therefore, PKM2 has been considered as a potential target for cancer therapy. Flavones have been examined for their effects on human PKM2 activity, and apigenin and tangeritin showed an inhibitory and activation effect, respectively. However, the effects of soy isoflavones on the human PKM2 activity have not been reported. In this study, the effects of genistein, glycitein, daidzein, (R)-equol, and (S)-equol were examined. All the examined compounds weakly inhibited human PKM2 activity and (R)-equol showed the most potent inhibitory activity with the IC50 value of 200μM. PKM2 has been reported to exist as a low-activity dimer and high-activity tetramer form. To examine whether the inhibition of the PKM2 activity by (R)-equol was caused by the shift from the tetramer to dimer, the composition of the PKM2 was analyzed by gel filtration chromatography. The chromatograms in the absence and presence of (R)-equol showed the same profile, suggesting that the inhibition was not caused by the switch from the tetramer to the dimer. (R)-Equol might directly bind to the active site of human PKM2.
Soy Protein Research, Japan 21, 155-158, 2018.
Key words : pyruvate kinase, genistein, daidzein, glycitein, equol
Mechanism of Female-Specific Anorectic Effect of the Microbial-Derived Isoflavone Metabolite S-equol
-Identification of S-equol Conjugates in Bile of Female Rat using Liquid Chromatography-Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry Analysis-
Mina FUJITANI*, Takuhiro KOBAYASHI and Taro KISHIDA
Department of Biological Resources, Faculty of Agriculture, Ehime University, Matsuyama 790-8566
ABSTRACT
Appetite control is an effective approach for obesity and its comorbidities. In the previous study, we have shown that S-equol produced by the intestinal microbiota after ingestion of its precursor daidzein, an isoflavone present in soy, decreases food intake specifically in female rats. Although S-equol is an estrogen receptor β agonist, anorectic effect of estradiol is more pronounced in male rats than in female rats. It is possible that their anorectic effects may be mediated by different mechanisms. Previous studies from our and other laboratories indicated that S-equol metabolizes to glucuronide and sulfate conjugates in liver and small intestine and undergoes an efficient enterohepatic circulation. Furthermore, we performed a procedure in which bile taken from female donor rats fed the daidzein diet was infused into the duodenum in other female rats fed the control diet. The bile infusion significantly decreased food intake in female rats, suggesting that the S-equol metabolites in bile induced the anorectic effect. Conjugate forms of S-equol have been determined in rat plasma and urine, but not bile. In this study, bile samples were collected after feeding of daidzein diet for 2 weeks in male and female Sprague-Dawley rats. Bile samples were subjected to direct electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF- MS/MS) analysis for the identification of S-equol metabolites. MS fragmentation patterns indicated that S-equol metabolites in bile were the 7-sulfate conjugate and the 4'-glucuronide conjugate in female rats. One or both of these conjugates may contribute to the anorectic effect. We speculated that female specific S-equol conjugates contribute to the anorectic effect, but S-equol 7-sulfate and the 4'-glucuronide were also detected in bile of male rats. Further studies are needed to determine whether sex differences in the conjugation of S-equol are associated with the female-specific anorectic effect.
Soy Protein Research, Japan 21, 159-166, 2018.
Key words : soy isoflavone, daidzein, equol, conjugate, appetite, enterohepatic circulation
Chrono-Nutritional Study of the Effect of Soy Protein Isolate and Soy Isoflavone on Muscle Hypertrophy in Mice
Shinya AOYAMA*1, 2, Rina HIROOKA2 and Shigenobu SHIBATA2
1Organization for University Research Initiatives
2Laboratory of Physiology and Pharmacology, School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480
ABSTRACT
Several physiological functions, including nutrient absorption and metabolism, show circadian fluctuations. Disruption of circadian rhythms in clock gene- deficient mice induced skeletal muscle atrophy and weakness. In this study, we evaluated the effects of soy protein isolate (SPI) and daidzein on skeletal muscle hypertrophy based on the feeding time of mice. Experiment 1: We investigated the time-dependent effects of SPI intake on skeletal muscle hypertrophy in mice. Mice were fed two meals per day, one at the beginning and one in the later active phase, with these meals defined as breakfast and dinner, respectively. When mice were fed the same amount of protein in a day, consuming excess SPI at dinner caused the skeletal muscle to grow to a greater extent in response to functional overloading than when consuming excess SPI at breakfast. The activity level of mice during the active phase, measured with an area sensor, decreased with SPI feeding at breakfast, suggesting that the muscle growth effect of excess SPI intake at dinner was locomotor activity dependent. Experiment 2: We investigated the time-dependent effects of daidzein intake on skeletal muscle hypertrophy in ovariectomized (OVX) mice. Mice were maintained on two meals per day. Daidzein intake promoted muscle hypertrophy in OVX mice. However, time- dependent effects were not observed. This suggests that daidzein accelerates muscle hypertrophy and that the feeding time-dependent effect is small.
Soy Protein Research, Japan 21, 167-172, 2018.
Key words : chrono-nutrition, feeding time, muscle hypertrophy, daidzein
Molecular Analysis of Soy Isoflavone in Mitochondrial Activity in Hepatocyte
Takakazu MITANI*
Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, NAGANO 399-4598
ABSTRACT
Adipocytes in obesity secretes excessive free fatty acid (FFA) in vessels, and secreted FFA accumulates in the liver. Excessive FFA causes oxidative damage in mitochondria of hepatocytes and results in an induction of cellular senescence of hepatocytes. The cellular senescence induces various diseases such as non-alcoholic fatty liver, hepatic fibrosis and hepatoma. Thus, suppression of FFA-mediated oxidative damage is important in preventing hepatic diseases. In this study, we investigated the effects of soy isoflavone on FFA-induced oxidative damage in the mitochondria of hepatocytes. Daidzein, one of the soy isoflavones, suppressed FFA-induced lipid accumulation in HepG2 cells. On the other hands, daidzein induced an increase in ketone body production. When we assessed the effects of daidzein on FFA-induced mitochondrial damage, daidzein attenuated FFA-induced mitochondrial DNA damage and increased the copy number of mitochondria in HepG2 cells. Daidzein up-regulated the expression of hydroxymethylglutaryl CoA synthase 2 (HMGCS2) at transcriptional levels. HMGCS2 regulates ketone body production, and its enzymatic activity is regulated by posttranslational modification. The acetylation level of HMGCS2 protein is decreased in the presence of daidzein. Furthermore, daidzein increased SIRT3 protein, and knockdown of SIRT3 canceled daidzein-induced deacetylation of HMGCS2. These results suggest that daidzein decreases lipid accumulation by increasing the conversion from FFA to ketone body and consequently prevents FFA-induced mitochondrial damage and increases mitochondrial number. Furthermore, deacetylation of HMGCS2 by SIRT3 is involved in these daidzein-induced effects in HepG2 cells.
Soy Protein Research, Japan 21, 173-179, 2018.
Key words : isoflavone, daidzein, mitochondria, hydroxymethylgutaryl CoA synthase 2, SIRT3
The Association Between Soy Product Intake and Sarcopenia in Patients with Type 2 Diabetes
Yoshitaka HASHIMOTO*
Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto 602-8566
ABSTRACT
The purpose of this cross-sectional study was to investigate the relationship between protein intake and sarcopenia in elderly patients with type 2 diabetes. We included the patients who had participated in the KAMOGAWA-DM cohort study, and received the diet survey and bio impedance method. Of the 304 patients (169 men, average age 72.5 (5.3) years old), 24 patients exhibited sarcopenia. The protein intakes (61.2 (23.0) g/day vs. 77.3 (34.0) g/day, p=0.024), especially vegetable protein intake (24.2 (7.3) g/day vs. 29.4 (10.8) g/day, p=0.022), in patients with sarcopenia were lower than those in patients without. In addition, the frequency of soy product intake in patients with sarcopenia tended to be lower than that in patients without (1.4 (1.3) time/day vs. 1.9 (1.2) time/day, p=0.058). Moreover, the vegetable protein intake was associated with the prevalence of sarcopenia after adjusting for age and sex (Δ1 g/day incremental odds ratio 0.94, 95%CI 0.89-0.99, p=0.013). In conclusion, protein intake, especially vegetable protein intake, was associated with sarcopenia in elderly patients with type 2 diabetes.
Soy Protein Research, Japan 21, 180-184, 2018.
Key words : protein, soy protein, sarcopenia, muscle mass, diabetes
Effects of a Soy Protein Diet on Thermogenic Hormone Secretion in Mice
Hirokazu TANIGUCHI*
Faculty of Agriculture, Ryukoku University, Kyoto 606-8233 (Laboratory of Health Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522)
ABSTRACT
Fibroblast growth factor-21 (FGF21) is an important metabolic regulator with multiple beneficial effects on thermogenesis and glucolipid metabolism in animal models of obesity. Although it was reported that obese individuals had a lower circadian rhythm of circulating FGF21, the role of changes in circulating FGF21 concentration has not been well examined. To examine the effects of circulating FGF21 rhythm on obesity and body fat distribution, this animal study used soy protein and beta-conglycinin, which were suggested as stimulating factors of FGF21. The 12-week feeding experiment showed that the long-term consumption of a casein, high-fat and high-fructose diet is associated with higher plasma FGF21 levels under feeding condition and lower plasma FGF21 levels under fasting condition, which are opposite to the rhythm of FGF21 in mice fed the control diet. On the contrary, soy protein and beta-conglycinin diets prevented the opposite changes in plasma FGF21 rhythm in mice regardless of high-fat high-fructose feeding. The mice fed the soy protein and beta-conglycinin diets had lower hepatic triglyceride contents compared with the casein diet group, and low amounts of mesenteric fat tissue are shown in mice fed the beta-conglycinin diet. These results suggest dietary consumption of soy protein, including beta conglycinin, has beneficial effects on circulating FGF21 rhythm and body fat distribution.
Soy Protein Research, Japan 21, 185-189, 2018.
Key words : FGF21, body fat distribution, beta-conglycinin
Different Effects of Equol Enantiomers, Metabolites of Isoflavone, on Reactive Oxygen Species as Cell Signal
Hirofumi INOUE*
Laboratory of Physiology and Metabolism, Department of Nutrition Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo 156-8502
ABSTRACT
Equol is a chiral molecule that exists as the enantiomers, (S)-equol and (R)-equol. Although both equol enantiomers have higher affinity for estrogen receptor (ER) than the biosynthetic precursor daidzein, the ER affinity and transcriptional activity may differ between equol enantiomers. Previously, our group reported that an inhibitory effect on bone loss was stronger with (S)-equol than with (R)-equol in ovariectomized animals. However, the details of the differences in inflammatory responses of both equol enantiomers are poorly understood. In the present study, we investigated the effects of equol enantiomers on the lipopolysaccharide (LPS)- induced inflammatory responses in RAW264.7 mouse macrophages and the underlying molecular mechanisms. We found that LPS-mediated nitric oxide (NO) production was markedly reduced in both (S)- and (R)-equol treated cells. Furthermore, the equol enantiomers down-regulated LPS-induced inflammation- associated gene expressions of inducible NO synthase, cyclooxygenase-2, interleukin-6 and interleukin-1β. Additionally, inhibition of LPS-mediated NF-κB and ERK1/2 phosphorylation were also suppressed by equol enantiomers. These results suggest that equol enantiomers might inhibit NO production and inflammation- associated gene expression, at least in part, by suppression of ERK1/2 signaling and NF-κB activity.
Soy Protein Research, Japan 21, 190-195, 2018.
Key words : equol enantiomers, nitric oxide, inflammation, macrophage, reactive oxygen species