Improvement in Zinc Nutrition and the Memory by Soybean Components
Taiho KAMBE* and Atsushi TAKEDA
Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502
Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526
ABSTRACT
Adequate zinc intake is indispensable to maintain health, because zinc plays critical roles in a wide variety of physiological processes. One of significant roles of zinc is that it is required for the proper brain functions. Synaptic zinc signaling is involved in synaptic plasticity such as long-term potentitaion (LTP), and memory, in which zinc transporters probably play significant roles. Therefore, increased attention is required to improve zinc nutrition and to prevent zinc deficiency in daily life. However, recent several reports indicate that dietary zinc deficiency risks are
decreasing but remain prevalent in developing countries and developed countries including Japan. In zinc absorption in the small intestine, the zinc transporter ZIP4 plays an essential role, and thus food component(s) that would enable an increase in cell surface ZIP4 expression would led to increases of cellular zinc levels. We previously reported that soyasaponin Bb is the potential to improve zinc nutrition, because it has the activity to increase mouse ZIP4 expression. Here, we investigated whether other soyasaponins, specifically, soyasaponin Ba, Aa, and Ab increases ZIP4 protein expression in human and mouse cells. We also examined the potential of soyasaponin Bb to rescue Aβ-mediated impairments of LTP, because ZIP4 is highly expressed in the hippocampus in the brain. Moreover, we examined whether the soybean extracts have the ability to increases of ZnT1 expression, after characterizing its basolateral localization in Caco2 cells. These studies are possibly a major step and facilitate our understanding in preventing zinc deficiency and improving brain functions.
Soy Protein Research, Japan 20, 1-7, 2017.
Key words : ZIP4, zinc absorption, soyasaponin Bb, LTP, amyroid β, ZnT1
Effects of Dietary Soy Protein and Whey Protein on Denervation-induced Skeletal Muscle Atrophy
Takeshi NIKAWA*1, Rie HASHIMOTO1, Reiko NAKAO1, 2, Takayuki UCHIDA1, Miyuki NINOMIYA1, Yuki KIMORI1, Ayako MAITA1, Ayaka TETSUNO1, Kurimi IDA1, Hikaru KISHIMOTO1, Marina TAKAGI1, Hiroaki YANAGAWA3 and Koichi SAIRYO4
1Department of Nutritional Physiology, Institute of Medical Nutrition, Tokushima University Graduate School, Tokushima 770-8503
2National Institute of Advanced Industrial Science and Techonology (AIST), Tsukuba 305-8561
3Tokushima University Hospital, Clinical Trial Center for Developmental Therapeutics, Tokushima 770-8503
4Department of Orthopedics, Institute of Medical Sciences, Tokushima University Graduate School, Tokushima 770-8503
ABSTRACT
Soy protein and whey protein are beneficial dietary proteins against unloadingmediated muscle atrophy, although they have distinct effects on the muscle atrophy. Soy protein has inhibitory effect on muscle protein degradation, while whey protein stimulates muscle protein synthesis. We reported here whether they have an additional effect on muscle atrophy, when the mixed diet with soy and whey proteins were subjected to denervated mice. We found that the ratio of the mixed protein diet was most effective to prevent the denervation-induced muscle atrophy. Thus, we are planning to perform the dietary intervention examination with the ratio of the mixed soy and whey protein diet for bed-redden people next year.
Soy Protein Research, Japan 20, 8-12, 2017.
Key words : denervation, muscle atrophy, whey protein, soy protein
The Clarification of Molecular Mechanism of the Improvement of Lipid Metabolism by Soybean β-conglycinin Based on the Novel Active Peptide Identification
Satoshi NAGAOKA*1 Toshirou 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
This experiment was designed to identify peptides which have bile acid-binding ability from soybean β-conglycinin. In this study, we used peptide array to evaluate the bile acid-binding ability of peptide derived from soybean β-conglycinin (hydrophobicity>0.8). In the peptide array, bile acid-binding ability was evaluated to the binding ability of taurocholic acid and fixed peptides on cellulose membrane, then binding peptides with taurocholic acid were detected by first antibody of bile acid, finally the antibody-taurocholic acid complexes were detected by second antibody. We found some bile acid binding peptides in this screening. In this context, we selected 40 kinds of peptides (eg. IIKLAIPV) to evaluate bile acid-binding ability and micellar solubility of cholesterol in vitro using soystatin (VAWWMY) as a positive control. Peptide X, Y was higher bile acid-binding ability in vitro than other synthesized peptides. Peptide Y was significantly lower micellar solubility of cholesterol than other synthesized peptides in vitro like cholestyramine as a positive control. We found for the first time that the portal blood plasma may contain some peptides derived from β-conglycinin after a single oral administration of β-conglycinin in rats.
Soy Protein Research, Japan 20, 13-18, 2017.
Key words : peptide, β-conglycinin, peptide array, bile acid, plasma peptide
Fundamental Study on Comprehensive Control of Soybean Rust
Yasuhiro ISHIGA*, Kouichi SHIGEMATSU and Yuichi YAMAOKA
Faculty 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. For controlling soybean rust, use of fungicides and creation of resistant varieties using resistant genes are being conducted, but there are also many issues such as environmental burden and the appearance of resistant races. Studies on biological control using mycoparasites as a means of controlling soybean rust have also been conducted. Simplicillium sp. separated from the uredinia of P. pachyrhizi has been revealed to infect into urediniospores. We also demonstrated that inoculation of soybeans with urediniospores of P. pachyrhizi together with Simplicillium sp. may inhibit lesion formation of soybean rust. However, we found that no infection occurred in urediniospores, germination tubes and appressoria, suggesting that suppression of lesion number of soybean rust by Simplicillium sp. is not due to direct parasitism to urediniospores. To further investigate the molecular mechanism of Simplicillium sp. mediated suppression of lesion formation caused by soybean rust, we especially focused on the induction of soybean defense responses by Simplicillium sp. The expression profile revealed that genes-related to ethylene signaling pathway was induced by simultaneous inoculation of P. pachyrhizi and Simplicillium sp. In addition, the ethylene treatment on the inoculated leaves suppressed the number of lesions of soybean rust. These results suggest that the ethylene-mediated signaling pathway induced by Simplicillium sp. is involved in suppression of lesions caused by soybean rust. In the future, it is essential to elucidate a more detailed mechanism to develop biological control agents based on mycoparasites including Simplicillium sp.
Soy Protein Research, Japan 20, 19-22, 2017.
Key words : Asian soybean rust, mycoparasite, Simplicillium sp., ethylene
Analysis of CLE Peptides on Plant Parasitic Nematode Infection Steps
Morihiro OOTA, Chie SHIMAOKA, Reila SUZUKI and Shinichiro SAWA*
Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555
ABSTRACT
Because of the agricultural importance, the soybean cyst nematode Heterodera glycines that infect soybean (Glycine max) and Meloidogyne incognita that infect 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. In order to increase knowledge of molecular mechanisms on plant-animal interaction, we have identified CLE like genes from plant-parasitic root-knot nematode, M. incognita . CLE peptide genes are encoded all of the land plant that were already examined, and they seem to conserve all of the plant. CLE peptides function non-cell autonomously in many aspects of plant physiology. On the other hand, only plant parasitic nematodes seem
to have CLE genes, indicating the importance on the plant infection steps. By using genome and RNA information of M. incognita , we have indicated five CLE genes. We have confirmed molecular nature of the CLE genes, and we also examined their function in plant by using transgenic plants. This information can be utilized for the defense of the nematode damage in an agricultural field.
Soy Protein Research, Japan 20, 23-26, 2017.
Key words : nematode, Arabidopsis, M. incognita , CLE, peptides
Pest Control of Soybean Plants using Plant-Plant Communications
Gen-ichiro ARIMURA*1, Satoru SUKEGAWA1 and Kaori SHIOJIRI2
1Department of Biological Science & Technology, Faculty of Industrial Science & Technology, Tokyo University of Science, Tokyo 125-8585
2Department of Agriculture, Ryukoku University, Otsu 520-2194
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. Mint volatiles have traditionally been noted for their ability to affect plants' interactions with arthropods and microorganisms, especially as repellants against them. Here we present a novel ability of mint volatiles acting as “plant-plant signals" for powerful pest control of agriculture crops. We assessed twelve varieties of the companion plants (Mentha spp.) that activated defense responses in neighboring crop plants. One of the mint varieties most strongly activated defense gene expression in soybean leaves after co-cultivaton with the mint. Field assays of soybeans suggested that valuable pest management and increased harvest were achieved by pre-cultivation with the mint plants. This pest control system relying on mint companion plants could be commercially useful for increasing agricultural crop production.
Soy Protein Research, Japan 20, 27-30, 2017.
Key words : herbivore, mint, plant-plant communications, soybean, volatiles
Promotion of Nitrogen Fixation Ability by a Novel Material Chitin Nanofibers in Soybean
Hironori KAMINAKA*1, Yukiko ISOWA1, Chihiro MIURA1, Mayumi EGUSA1 and Shinsuke IFUKU2
1Department of Agricultural, Life and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori 680-8553
2Graduate School of Engineering, Tottori University, Tottori 680-8552
ABSTRACT
Legumes can effectively utilize atmospheric nitrogen by symbiosis with rhizobia. The reduction of usage of nitrogen fertilizer, therefore, would be feasible by promoting legume-rhizobia symbiosis. In this study, we conducted basic research
on the promotion effect of chitin nanofibers (NF) on rhizobial symbiosis in a main legume crop soybean, providing the fundamental knowledge for development of utilization technology of chitin NF to reduce the use of fertilizer on soybean cultivation. The addition of chitin NF promoted the growth of the aerial part of the soybean inoculated with rhizobia, as shown previous study in Lotus japonicus . We newly found that the treatment of chitin NF increases nitrogen fixation ability as acetylene reduction activity. Transcriptome analysis of soybean treated with chitin NF demonstrated that there are many genes specifically induced by chitin NF. Of those, expression levels of genes involved in the maintenance of nitrogen fixation, like transcriptional regulators related to signal transduction of jasmonic acid, and leghemoglobin, were increased. These results revealed that the chitin NF-specific promotion effect on rhizobial symbiosis is widely common among legumes, and that this effect is caused by the activation of nitrogen fixing ability of symbiotic rhizobia.
Soy Protein Research, Japan 20, 31-36, 2017.
Key words : chitin nanofiber, nitrogen fixation, soybean-rhizobia symbiosis, transcriptome
Identification of Glycerolipid-oxylipins in Soybean Seeds and Study on the Mechanism to Form Them
Kenji MATSUI*
Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515
ABSTRACT
In order to find out novel bioactive compounds in foods made from soybean seeds, we attempted to detect glycerolipid-oxylipin in raw soymilk. Because some of glycerolipid-oxylipins are known to have bioactivities such as activation of PPAR α in mammalian cells, we focused on the oxidized lipids. When trilinolein was used as the substrate for soybean seed lipoxygenases, we found a substantial activity with the substrate suspended in a certain condition. HPLC-MS/MS analysis nicely separated trilinolein and its oxidized forms, and based on their spectrum and MS profiles, we found that bishydroperoxide, monohydroperoxide/monooxo, monohydroperoxide, and monooxo of trilinolein were formed during the enzyme reaction. When crude lipid extract prepared from raw soymilk was served to the same HPLC-MS/MS analysis, we found two groups of peaks consisted of lipids with two oxygenation and those with one oxygenation. They seemed to be novel esterified oxylipins formed during food processing of soybean seeds. Further purifi cation is needed to confirm their structures, and also to identify their bioactivity.
Soy Protein Research, Japan 20, 37-42, 2017.
Key words : glycerolipid-oxylipins, lipoxygenase, HPLC-MS/MS
Identification of Genes Controlling the Accumulation of Sugars in Edamame Seeds Using F2 Population Derived from Crossing Normal Soybean Cultivar, Enrei, and Edamame Cultivar, Dadachamame
Tomoki HOSHINO*, Rina AWANO, Chiho KAMIMURA, Kana TAKIGUCHI, Tamae KAWAKAMI and Nobushige IIJIMA
Department of Food, Life, and Environmental Sciences, Faculty of Agriculture, Yamagata University, Tsuruoka 997-8555
ABSTRACT
The Dadachamame cultivar ‘Shirayama’ was established in Yamagata Prefecture, northern Japan, in the late Edo era. The ‘Shirayama’ is good taste because it has an attractive sweet taste. Comparison of chemical components in seeds of Dadachamame cultivars and other soybean cultivars has shown that the sweet taste of Dadachamame cultivars are caused by higher sucrose levels, but the genetic determinants of this difference are unclear. In this study, we cultivated 478 F2 individuals derived from crosses between Dadachamame cultivar ‘Shirayama’ and the normal soybean cultivar ‘Enrei’. Transgressive segregations for flowering time and sucrose content were detected in the F2 population. Although the scatter plot for flowering time and sucrose content from the F2 individuals indicates a weaker negative correlation, transgressive segregation for sucrose content was detected in the limiting flowering day. These results suggest that newly developed F2 population is effective for molecular genetics approaches and high accumulation of sucrose in ‘Shirayama’ seeds is clearly under genetic control. Using the F2 population and polymorphic SSR markers between ‘Shirayama’ and ‘Enrei’, we intend to identify quantitative trait loci (QTL) that control high accumulation of sucrose in Dadachamame seeds. We will discuss the mechanisms of sugar metabolism in Dadachamame seeds that could be used in future studies for improving the eating quality of edamame.
Soy Protein Research, Japan 20, 43-46, 2017.
Key words : Dadachamame, molecular genetics approach, quantitative trait loci, Shirayama, sucrose, sweet taste
Molecular Mechanism of Derivation of Anti-Cancer Peptide, Lunasin, from 2S Albumin, and Its Application to the Processed Foods of Soybean
Tomohisa OGAWA*, Ichiko HIRAKAKIUCHI, Mayumi TSUBONO, Rui SATO, Mai YUKAWA and Koji MURAMOTO
Department of Molecular Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577
ABSTRACT
The soybean peptide called lunasin, which constitutes 2S albumin together with long (L) chain, is known to have anti-cancer and anti-inflammatory effects. Although lunasin has been reported to be contained in various soybean-products, it is hardly found in raw soybean. Moreover, the derivation of lunasin from 2S albumin during food processing has remained unclear. In this study, we investigated the formation of lunasin from 2S albumin under various processing conditions using specific antibodies against lunasin and 2S albumin. Anti-pre-2S albumin antibody was also used to explore the formation of 2S albumin from its precursor, pre-2S albumin in maturing soybeans. Lunasin was most abundantly contained in low-fat soymilk among various soybean-products; e.g., soymilk, boiled soybean and its soup, enzymedeactivated soyflour, roasted soyflour and soy-yogurt, though the peptide was not detected in raw soybeans. Lunasin was produced in a time-dependent manner by heating at 90°C, meanwhile, 2S albumin was decreased by its S-S exchange reaction. Nevertheless, lunasin could not be identified in isolated 2S albumin by the same treatment. It was found that enzymes including protein disulfide isomerase and purothionin (thioredoxin-like enzyme) were not participated in the cleavage. These results suggest that other soybean components are involved in derivation of lunasin from soybean 2S albumin. On the other hand, pre-2S albumin was expressed in filling soybean 4-6 weeks after flowering and processed after 7 weeks.
Soy Protein Research, Japan 20, 47-51, 2017.
Key words : 2S albumin, antibody, processed foods, lunasin, soybean peptide
Development of Soybean-Based Raw Food Material Using Glutathione
Fumiyo HAYAKAWA, Junko MATSUKI and Hiroyuki YANO*
Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642
ABSTRACT
Inter- and intramolecular disulfide crosslinking of protein plays critical roles in the processing property of foods. The aim of this research was to explore the possibility of developing soybean-based raw food material using glutathione. Glutathione is a natural tripeptide composed of glycine, cysteine and glutamic acid. Two molecules of reduced glutathione occasionally form into oxidized glutathione through intermolecular disulfi de bonding. Both reduced/ oxidized glutathiones are capable of modifying disulfi de crosslinking of the target proteins in food materials. In this research, glutathione was shown to cleave the disulfi de bonds of proteins in soy flour: specific fluorescence labeling has shown that addition of glutathione increased the amount of free SH group of soy protein. Instrumental measurements using a RheoMeter CR-500DX have shown that reduced and oxidized glutathiones have their respective effects on the physical property of soy flour dough. Especially, adding 1% of reduced form of glutathione against soy flour protein (wt/ wt) made the soy flour dough softer and stickier. Effect of glutathione on the processing suitability of the soy flour dough was also investigated on a pasta machine. Oxidized glutathione made better pasta from soy dough than reduced glutathione. Sensory evaluation based on the Check-all-that-apply (CATA) method demonstrated more detailed differences in the physical property of soy flour doughs. In summary, potential applicability of glutathione on the development of soy products with various physical properties was suggested here.
Soy Protein Research, Japan 20, 52-56, 2017.
Key words : disulfi de, glutathione, pasta, sensory evaluation, soy flour dough
Nanostructure of Soy Proteins as Revealed by Small-Angle X-ray and Neutron Scattering
Nobuhiro SATO*1, Masaaki SUGIYAMA1 and Reiko URADE2
1Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494
2Graduate School of Agriculture, Kyoto University, Uji 611-0011
ABSTRACT
The small-angle X-ray scattering (SAXS) technique was utilized for investigating nano-scale structural change accompanying the preheat treatment and the addition of glucono-δ-lactone (GDL) to two major soy proteins, β-conglycinin (7S) and glycinin (11S). SAXS profiles for 0.5% buffer solutions of 7S suggest the hexamer formation from trimers of subunits with decreasing ionic strength. For 3% solutions of 7S in pure water, no obvious structural change was observed even at elevated temperatures below 50°C. However, above 60°C, thermal denaturation partly occurred and finally 7S changed to random structures above 70°C. When GDL was added after preheated at 50°C, large structural changes over 30 nm were observed while no change appeared in 5-10 nm scale. This indicates that gluconic acid formed from GDL reacted with 7S via the small structural changes on the surface of 7S molecules while keeping its original subunit structure. At the preheating temperature of 100°C, in contrast, entire structural changes took place through thermal denaturation and finally large coagulation structures formed in the whole system.
Soy Protein Research, Japan 20, 57-62, 2017.
Key words : SAXS, β-conglycinin, glycinin, thermal denaturation, coagulation
Antimicrobial Activity and Mechanism of Action of Cationic Peptides from Soybean Protein Hydrolysates
Masayuki TANIGUCHI*
Department of Materials Science and Technology Faculty of Engineering, Niigata University, Niigata 950-2181
ABSTRACT
Food proteins provide organisms with the amino acids necessary for the maintenance of life. Recently, another function of food proteins has become well known; they are a source of antimicrobial peptides (AMPs). These peptides are inactive within the sequence of the parent protein and must be released during gastrointestinal digestion, fermentation, or food processing. AMPs can be generated from proteins of different food origins, including soybean, milk, egg white, and wheat. In this study, we selected hydrolysates of soybean proteins as a source of AMPs. We prepared fractions with cationic peptides from hydrolysates of soybean proteins by autofocusing. The antimicrobial activity of the cationic peptide fractions against human pathogens was quantitatively evaluated using a chemiluminescence method that measures ATP derived from viable cells. The peptide fractions exhibited antimicrobial activity against Porphyromonas gingivalis (a periodontal disease-associated bacterium) and Propionibacterium acnes (an acne-related Grampositive bacterium), but not against Candida albicans (an opportunistic fungal pathogen). After we purified the peptides in some fractions with antimicrobial activity by reversed-phase chromatography, the peptides were identified by matrixassisted laser/desorption ionization-time-of-flight mass spectroscopy (MALDI-TOF/ MS). To date, we have identified 23 types of peptides. In a future study, we will chemically synthesize peptides with high isoelectric points and positive net charges, and examine their antimicrobial activity against human pathogens.
Soy Protein Research, Japan 20, 63-67, 2017.
Key words : cationic peptide, soybean protein, antimicrobial activity, mechanism of action, human pathogen
Regulatory Action of Soy Isoflavone on MicroRNA Expression
Hirofumi TACHIBANA*1, Shuya YAMASHITA2 and I-Chian Lin1
1Division of Applied Biological Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581
2Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Kagoshima 898-0087
ABSTRACT
MicroRNAs (miRNAs), the small RNAs that have function to regulate gene expression, have recently attracted attention as molecules that relate to homeostasis and diseases. The relationship between the physiological effects of food factors and miRNAs have been mostly unknown. In the present study, we investigated the effect of soy isoflavones on miRNA expression and its mechanism. Oral intake of daidzein changed several serum-miRNAs expressions in mice. Daidzein also changed some serum-miRNAs expressions that other phytochemicals did not affect. In human cervical cancer cell line HeLa, miR-320a was identified as in miRNA whose expression level was up-regulated by isoflavone treatment. Isoflavone also decreased the protein expression of β-catenin encoded by CTNNB1, which is a target gene of miR-320a. So far, we have identified pap=associated domain containing 5 (Papd5) as the critical gene for cell growth-inhibitory action of isoflavones that are estrogen receptor-independent. Gene silencing of Papd5 canceled the miR-320a-increasing effect of equol. These results suggest that soy isoflavones increase miR-320a expression and suppress translation of miR-320a's target gene in the Papd5-dependent manner.
Soy Protein Research, Japan 20, 68-71, 2017.
Key words : isoflavone, microRNA, anticancer effect, Papd5.
Anti-Neuroinflammatory Effects of the Soy Isoflavone Genistein in the Hippocampus of Mice Received Short-Term 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
Schizophrenia is a complex and debilitating mental illness, which is estimated to affect 0.5-1.0% of the population worldwide. Although the dopamine hypothesis of schizophrenia was formulated in the 1960s, recent epidemiological data suggest that neuroinflammation may also underlie the pathogenesis of this illness. Interestingly, some studies have reported the clinical and preclinical benefits of the adjunctive treatment of schizophrenia patients using estradiol, which is known to exert an antiinflammatory action. To address this issue further, here we examined the potential effects of soy isoflavone, genistein, on the brain immune cells called microglia in the hippocampus of mice received short-term (2 weeks) exposure to cuprizone, a neuroinflammation model of schizophrenia. The numerical densities (NDs) of ionized calcium binding adaptor molecule 1-positive (Iba1+) microglia were increased in the majority of hippocampal layers in cuprizone-treated mice. Contrary to expectations, administration of genistein did not counteract this cuprizone-induced increase in microglia. In contrast, the expression ratios of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), an inflammation-associated transcription factor, in Iba1+ microglia were increased in the CA1 regions in cuprizone-treated mice. Importantly, administration of genistein reduced the expression ratios of pSTAT3 in the strata oriens and pyramidale of this area. Some morphological changes were observed in Iba1+ microglia of cuprizone-treated mice, and these were counteracted by genistein administration. The present findings indicate that inflammatory changes in hippocampal microglia in cuprizone-treated mice may be reduced by genistein, and also suggest that genistein can be a promising adjunctive for treatment of schizophrenia.
Soy Protein Research, Japan 20, 72-80, 2017.
Key words : hippocampus, neuroinflammation, cuprizone, microglia, schizophrenia
Anti-Inflammation Effect of Soyaflavone HG on Murine RAW264.7 Macrophage Cells in Response to Lipopolysaccharide
Sang Eun Kim and Mitsuo MARUYAMA*
Department of Mechanism of Aging, National Center for Geriatrics and Gerontology (NCGG), Obu 474-8511
ABSTRACT
Soybean isoflavones have been identified as having an anti-inflammation and antioxidant effect in various types of cells and animals. Here we investigated that effect of water-soluble soybean isoflavones (Soyaflavone HG; supplied by Fuji oil Co., LTD.) consists of glycosides-form isoflavones including daidzein, glycitein and genistein. First, we tested the effect of Soyaflavone HG on RAW264.7 murine macrophage cell line, in response to lipopolysaccharide (LPS). We confirmed that LPS-induced nitric oxide (NO) productions and mRNA levels of pro-inflammatory cytokines, such as interleukin 1 beta (IL-1β) and interleukin 6 (IL-6) were decreased by pre-treatment of Soyaflavone HG on RAW264.7 cells. Then we verified that inducible nitric oxide synthase (iNOS) expression was down regulated by Soyaflavone HG treatment on both mRNA and protein levels. Furthermore, we demonstrated that Soyaflavone HG could suppress NF-kappa B (NF-κB) transcriptional activity through inhibition of NF-κB translocated to nucleus, in response to LPS treatment. This suggests that Soyaflavone HG has anti-inflammatory effects are due to diminished excessive NO production in activated macrophages by suppressing iNOS expression via NF-κB nuclear translocation.
Soy Protein Research, Japan 20, 81-88, 2017.
Key words : soy isoflavones, RAW264.7, NF-κB, iNOS, nitric oxide
The Effect of Dietary Isoflavone Daidzein on ERRα that Regulates Fatty Acid Metabolism-Related Genes in C2C12 Muscle Cells
Kaoruko IIDA*
Department of Nutrition and Food Science, Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo 112-8610
ABSTRACT
Many epidemiological studies show that intake of isoflavones play a beneficial roles in preventing obesity, however, the mechanism of the anti-obesity effects is unclear. This study therefore aimed to clarify the effects of daidzein, one of soy isoflavones, on transcription factor ERR α which has a crucial role on ‘fat barning’ in skeletal muscles. ERR α-expressed C2C12 myoblasts were differentiated then treated with daidzein for 48 hr. The effects of daidzein on transcriptional activity of ERR α were assessed by a reporter assay based on the promoter of PDK4 (pyruvate dehydrogenase kinase 4). When C2C12 myotubes were treated with daidzein for 48h, there were significant increases in the expression of ERR α target genes, such as PDK4, MCAD (medium-chain acyl-CoA dehydrogenase) and CPT1-β (carnitine
palmitoyltransferase-1β). ERR α specific inhibitor XCT790 suppressed the increases of these genes' expression by daidzein. In a reporter assay, daidzein upregulated PDK4 promoter activity, We also found that the ERR α responsive elements were necessary for the daidzein-induced increase of PDK-4 promoter activity. In conclusion, daidzein increased the expression of genes such as PDK-4 and MCAD in C2C12 myotubes through the ERR α. These effects of daidzein might enhance fatty acid oxidation in muscles, thereby improving obesity.
Soy Protein Research, Japan 20, 89-94, 2017.
Key words : daidzein, skeletal muscles, ERRα, fat oxidation
Study on the Effect of Soy Peptides on Chronological Life Span of Yeast
Yoshiharu INOUE* and Kayo IKEDA
Laboratory of Molecular Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji 611-0011
ABSTRACT
Life span is evaluated by two distinct criteria, i.e., replicative life span and chronological life span. Replicative life span is measured as the number of cell divisions that an individual cell can undergo, whereas chronological life span is
measured as the survival time of populations of non-dividing (G0 phase) cells. The budding yeast Saccharomyces cerevisiae is an excellent model organism to analyze both replicative life span and chronological life span. Calorie restriction has been known to slow the senescence of animals as well as yeast. TOR (target of rapamycin) signaling in eukarya is a crucial pathway of which the activity responds to a nutritional cue. TOR is a Ser/Thr kinase evolutionally conserved from yeast to man. TOR forms two distinct complexes, TOR complex 1 (TORC1) and TOR complex 2 (TORC2). Notably, inhibition of TORC1 is known to extend the chronological life span of yeast and mouse. In the present study, we found that soy peptides (HINUTE AM) increased the chronological life span of yeast. Soy peptides did not inhibit the TORC1 activity; however, we revealed that the TORC2-Pkc1 signaling pathway was involved in the regulatory mechanism of the chronological life span in yeast. Mutants defective in TORC2 (avo3-30 ) and protein kinase C (pkc1 Δ) exhibited a shortened chronological life span, and soy peptides extended it. Since soy peptides extended the chronological life span of pkc1 Δ cells, the effect of soy peptides on the extension of chronological life span is thought to extend to some factor(s) downstream of TORC2-Pkc1 signaling pathway, or to some factor(s) functioning independently of this pathway.
Soy Protein Research, Japan 20, 95-101, 2017.
Key words : chronological life span, yeast, soy peptides, TOR complex, protein kinase C
Nitrogen-Based Symbiotic Combination of Soybean Resistant Protein and Probiotics
Takao NAGANO* Yutaka UYENO*1, Tasuku OGITA1, Takahiro ISHIGURO2 and Takeshi SHIMOSATO*1, 3
1Academic Assembly (Institute of Agriculture), Shinshu University, Kamiina 399-4598
2Research Institute, Asahimatsu Foods Co., Ltd., Iida 399-2561
3Research Center for Fungal and Microlobial Dynamism, Shinshu University, Kamiina 399-4598
ABSTRACT
We previously revealed the availability of soybean resistant protein (SRP) derived from frozen soybean curd for manifesting specific groups of animal intestinal microorganisms. In the present study we carried out an in vivo experiment to determine prebiotic effects of SRP on mouse intestinal ecology and an in vitro experiment to extract possible probiotic bacteria that was applied together with the prebiotic SRP. In the mouse experiment commercially available isolated soybean protein was enzymatic digestion and processing and hydrochloric acid treatment to obtain SRP material, which was then mixed with a standard ration and pelletized. Female C57BL/6J mice were divided into two groups and fed either a control diet (CON) or the control diet plus SRP for two weeks. DGGE analyses for intestinal bacterial communities resulted in remarkable changes in response to SRP feeding, found in both the fecal community and the cecum community. In addition, feeding SRP induced immune regulatory effects to some extent. Our results implied that feeding SRP may affect enteric microbial community composition and immunological responses in the mouse gut. In the batch cultivation experiment simulating mouse large intestine, we applied Bacillus subtilis strains for co-cultivation with SRP based on results of a preliminary experiment. With the addition of SRP along with the Bacillus , volatile fatty acid production and numbers of bacteria increased significantly compared to control, implying that this strain in combination with SRP may coordinately work as a symbiotic in animal lower gut.
Soy Protein Research, Japan 20, 102-107, 2017.
Key words : Bacillus subtilis , intestinal microbial community, probiotics, soybean resistant protein
Comparison of the Effects on Non-Alcoholic Fatty Liver Disease between Soy Protein Isolate and Mung Bean Protein Isolate
Hiroshi INOUE*
Metabolism and Nutrition Research Unit, Innovative Integrated Bio-Research Core, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-8641
ABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is a spectrum of chronic hepatic disorders caused by hepatocyte triglyceride accumulation, including non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). There is an urgent need of therapeutic development of NAFLD prevention and treatment because of its progression to cirrhosis and its increasing prevalence. In this study, we have assessed the benefit of mung bean protein isolate (MPI) in the prevention and treatment of NAFLD. We have investigated the effects of MPI, as compared with casein and soy protein isolate (SPI) on hepatic lipid accumulation by feeding mice a high-fat diet containing casein, MPI, or SPI as a source of alimentary protein for 4 weeks. MPI suppressed hepatic triglyceride levels more strongly than casein and SPI. We then investigated the effects of MPI on the NAFLD progression by feeding mice a high-fat, high-cholesterol diet for 20 weeks, which induces hepatic inflammation and fibrosis, like NASH, in addition to hepatic lipid accumulation. MPI-feeding ameliorated hepatic lipid accumulation and fibrosis as well as reduced gene expression associated with inflammation and fibrosis. These findings suggest that MPI have a strong effect on reducing hepatic lipid accumulation and hence may be useful as a foodstuff that prevents NAFLD progression with a potential to suppress hepatic inflammation and fibrosis.
Soy Protein Research, Japan 20, 108-112, 2017.
Key words : NAFLD, mung bean protein isolate, SPI, lipogenesis
Use of Soluble Dietary Fiber for the Improvement of Gut Environment in Children with Autism Spectrum Disorder
Ryo INOUE*1 and Yuko SAKAUE2
1Laboratory of Animal Science, Kyoto Prefectural University, Shimogamo, Kyoto 606-8522
2Department of Pediatrics, Shiga medical University, Otsu 520-2192
ABSTRACT
It is thought that gut environment, especially microbiota composition, affects the severity or development of autism spectrum disorder (ASD). We speculated that the abnormal gut microbiota composition (dysbiosis) in ASD is at least partially due to the lack of dietary fiber because most ASD children tend to have specific food preferences. In this study, we evaluated the effect of soluble dietary fiber on constipation, irritability and gut microbiota of ASD children. Soluble dietary fibers from two different sources were used in this study. One soluble fiber (S) was given to 9 ASD infants and the other fiber (G) was to 6 ASD infants by adding them to rice for 4 weeks. The frequency of defecation was significantly increased and the irritability score was significantly decreased in both groups after 4 weeks. Unexpectedly, however, the composition of gut microbiota was not drastically changed although the abundance of several genera was significantly changed. The bacterial genera changed was different depending on the type of dietary fiber. This study suggests that supplementation of soluble dietary fiber could improve gut environment and consequently quality of life in ASD infants.
Soy Protein Research, Japan 20, 113-117, 2017.
Key words : gut microbiota, dietary fiber, autism spectrum disorder, constipation, irritability
Research on Adaptation Mechanism of Insects to Pea Albumin 1
Takako ABOSHI1
Laboratory of Bioorganic Chemistry, Plant and Bioresource Science Course, Department of Food, Life and Environmental Science, Faculty of Agriculture, Yamagata University, Tsuruoka 997-8555
ABSTRACT
PA1b (pea albumin 1, subunit b) is a plant peptide purified from pea seeds, that is lethal to some insects, such as the cereal weevils (Sitophilus oryzae, S. zeamais, S. granarius ) or the pea aphid (Acyrthosiphon pisum ). PA1b consists of 37 amino acids (ASCNGVCSPFEMPPCGTSACRCIPVGLVIGYCRNPSG), cross-linked by three disulfi de bonds. It has been demonstrated that PA1b inhibits the V-ATPase activity by binding with the c and e subunit of V-ATPase. In insects, the V-ATPase is present on the midgut brush border and essential for energizing nutrient absorption. Whilst lepidopteran larvae are insensitive to PA1b, its binding to the membrane extracts has been observed in all larvae tested. Thus, PA1b seems to be
prevented from reaching V-ATPase in the gut of lepidopteran larvae. In this study, we compared profiles of PA1b-related peptides in pea seeds, gut contents and frass of Spodopetra litura larvae reared on the pea seeds by LC/MS. The pea seed extracts contained peptides with molecular masses of 3,741 (PA1b), 3,805, 3,757, 3,727 and 3,752 Da, in which PA1b was detected at the level more than twice as much as the other peptides. However, the ratio of PA1b to the other peptides decreased in the frass, and the peptides with 3,805 and 3,757 Da were the major components among them. This result suggests that degradation or modification of PA1b could occur in the gut to confer PA1b resistance.
Soy Protein Research, Japan 20, 118-122, 2017.
Key words : pea albumin, insecticidal peptide, Spodoptera litura , gut metabolism
Hatching Stimulants for Soybean Cyst Nematodes
Shinsaku ITO*
Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo 156-8502
ABSTRACT
Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a plant parasitic nematode that causes the most serious damage in soybean fields. Glycinoeclepin A, B and C (GEs) are natural hatching stimulants isolated from the roots of kidney beans. Although GEs are good chemicals for the control of SCN hatching, their application is restricted because of their complex synthetic routes. In addition, except these three GEs, hatching stimulants have not been identified. In this study, we screened the chemical library to find chemicals that stimulate SCN hatching. We discovered 1,10-phenanthroline and its derivatives as novel hatching stimulants.
Soy Protein Research, Japan 20, 123-126, 2017.
Key words : soybean cyst nematode, glycinoeclepin, 1,10-phenanthroline
Prediction of the Diffusion Process of NaCl in Gels Prepared with SPI during Heating in Seasoning Liquid
Yoko SATO*
Faculty of Core Research, Natural Science Division, Ochanomizu University, Tokyo 122-8611
ABSTRACT
A 22.5% SPI, 15% SPI-7.5% starch (potato) complex, and a 22.5% starch gel were soaked in a 0.2 mol/L NaCl solution at 20°C, 50°C, and 70°C. The diffusion coefficient of NaCl in the gel was determined from changes in the NaCl concentration of the gels using a computer program based on the three-dimensional diffusion equation and was expressed by the Arrhenius equation. The diffusion coefficients of the SPIstarch gel at each temperature were almost the same as those of the starch gel, whereas those of the SPI gel were approximately half of those of the other gels. None of the gels heated to 98°C collapsed, even after heating for 60 min. Changes in the weights of the gels were small, in the order of SPI gel < SPI-starch gel < starch gel. On the other hand, changes in the hardness of the SPI-starch gel and the starch gel were small and similar, and these were softer than the SPI gel. These results clarified that starch has a large influence on the SPI-starch gel, because the addition of starch to SPI softens the gel and facilitates the diffusion of NaCl. Because the predicted values of changes in NaCl concentration in the gels heated at 98°C were in close agreement with the measured values for each gel, it was confirmed that the prediction of NaCl diffusion is possible for each gel using the diffusion coefficients obtained in this study.
Soy Protein Research, Japan 20, 127-131, 2017.
Key words : SPI, starch, diffusion coefficient, NaCl
A Method to Increase in Food Preference for Soybean Products and Frequency of Their Consumption
—Ripple Effect on Home—
Tomoko OSERA*
Hygiene and Preventive Medicine, Faculty of Home Economics, Kobe Women's University, Kobe 654-8585
ABSTRACT
Soybean products are healthy and an important sources of vegetable protein in Japan. This study evaluated a nutrition education program using school lunches, focusing on soybean products and food preferences in kindergarten-age children. In addition, the study examined the effects of using soybean products at home on reducing children's dislike of these products. A quasi-experimental pretest-posttest design was used to examine the effect of using school lunch programs with soybean products on children's food preferences. The participants were 134 children aged 3 years who attended kindergarten classes. The nutrition education group (NE, n=50) and nutrition education plus gardening group (NE+G, n=51) received basic nutrition education during lunchtime (4 days/week), including the use of informative place mats, and information about soybeans provided by teachers and nutritionists. We also provided nutritional information regarding soybeans to the children's guardians. The NE+G group also grew beans in a garden. The control group (CTL, n=33) included children from another kindergarten who received school lunch 5 days/week. Using paired t-test after analysis of variance, we compared the scores among the three groups before and after the intervention. Based on food preferences, the percentage of children with no food preference was significantly higher in the NE group than in CTL (p <0.05). Nutrition education using school lunches with soybean products may increase the percentage of children with no food preferences.
Soy Protein Research, Japan 20, 132-138, 2017.
Key words : soybean products, children, school lunch, intervention, place mat
Mechanisms of miRNA Regulation by Soy Isoflavones
Keitaro HAGIWARA*
Department of Medical Technology, Faculty of Biomedical Engineering, Toin University of Yokohama, Yokohama 225-8503
ABSTRACT
Diet is one of the most important modifiable cancer risk determinants. Dietary components have been implicated in many pathways involved in carcinogenesis. In addition, carcinogenic processes are associated with the altered expression of several miRNAs. MicroRNAs (miRNAs) that attenuate translation, for targetspecific gene silencing has rapidly created a powerful tool for the exploration of pathogenesis of human cancer. The inhibition of the miRNA biogenesis pathway results in severe developmental defects and lethality in many organisms. Deregulation of miRNAs leads to the development of several types of diseases. In fact, more than 70 diseases have been reported to be associated with miRNA deregulation. We hypothesized that the dietary intake of natural products maintains tumour-suppressive miRNA expression in cancer cells, leading to the prevention of carcinogenesis. Indeed, we previously demonstrated that resveratrol suppresses cancer cell malignancy in vitro and in vivo through the transcriptional activation of tumour-suppressive miRNAs and Argonaute2 (Ago2). In this study, we discoverd that soy isflavones, daidzein and its metabolite equol, showed the inhibition of several cancer cell lines. To confirm whether miRNAs are globally upregulated in the cytotoxic effects induced by equol in cancer cells, we performed a comprehensive miRNA profiling of untreated cancer cells and compared the results to those obtained in soy isoflavones-treated cells. We found that equol specifically up-regulated miR-4298, -3653-3p, -4532, -6860, -6756-3p, -379-5p, -4668-5p, -29c-5p, -6808-5p, -671-5p and down-regulated miR-1181, -6068, -34a-3p, -7111-3p, -6766-3p, -3679-3p, -5010-3p, -4257, -4646-3p, -183-3p, -29a-5p, -431-3p, -6851-3p, -33b-3p, -6795-3p compared to daidzein. These findings indicated that equol can regulate specific miRNAs, leading to tumour suppression.
Soy Protein Research, Japan 20, 139-142, 2017.
Key words : cancer, microRNA, equol, daidzein
Application to Brain Degenerative Diseases of the Soybean-Derived Vitamin K to Induce Neural Stem Cell Differentiation
Yosihisa HIROTA* and Yoshitomo SUHARA
Department of Bioscience and Engineering College of Systems Engineering and Science, Shibaura Institute Technology, Saitama 337-8570
ABSTRACT
Vitamin K homologues in human and mouse living organisms are converted to MK-4 by UBIAD1. Since MK-4 is present at high concentration in the brain and UBIAD1 also strongly expresses, MK-4 and UBIAD1 are likely to play an important role in brain function. In recent years, vitamin K and UBIAD1 have been reported to be involved in neurodegenerative diseases of the brain. Therefore, we examined what role vitamin K contained in soybean and its fermented product natto plays in the brain. First, we found that MK-4 differentiates mouse embryonic-derived neural stem cells into Map 2 positive neurons. Other vitamin K homologues showed the effect of inducing the differentiation of neural stem cells into Map 2 positive neurons like MK-4. Differentiation inducing effects were observed depending on the degree of unsaturation and length of the side chain. Furthermore, differentiationinducing activity was evaluated using vitamin K derivatives which selectively induce differentiation into neurons more selectively. As a result, fluorinated benzene having a nitrogen atom introduced at the side chain end showed the highest activity. This study to demonstrate the effectiveness of vitamin K from a molecular nutritional point of view gives important knowledge to elucidate vitamin K action in the brain. Therefore, this research is expected to be able to provide useful information for prevention and treatment strategies of neurodegenerative diseases.
Soy Protein Research, Japan 20, 143-150, 2017.
Key words : vitamin K, neural differentiation, brain degenerative disease, conditional knockout mice, purkinje cell
Treatment of Genistein Ameliorates Oxidative and ER Stress-Induced Hepatic Disorder in Prx4 and SOD1 Double Knockout Mouse
Takujiro HOMMA*, Ryusuke AKIHARA, Toshihiro KURAHASHI, Jaeyong LEE and Junichi FUJII
Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, Yamagata 990-9585
ABSTRACT
Among multiple factors, oxidative stress and endoplasmic reticulum (ER) stress are promising causes for developing steatosis and the progression of non-alcoholic steatohepatitis (NASH). It has been reported that mice deficient for superoxide dismutase 1 (SOD1), a superoxide-detoxifying enzyme, spontaneously develop steatosis. We have previously demonstrated that the coordinate action of oxidative stress and following ER stress caused by SOD1 deficiency are the underlying mechanism for lipid droplet accumulation in primary cultured hepatocytes. At the same time, peroxiredoxin 4 (Prx4) works on coupling hydrogen peroxide catabolism with oxidative protein folding in ER and hence exerts protection against oxidative stress via elimination of hydrogen peroxide. In fact transgenic overexpression of human Prx4 protects mice against the progression of NASH that is triggered by feeding a methionine- and choline-deficient (MCD) diet. In the current study, we generated Prx4 and SOD1 double knockout (Prx4-/-Sod1-/-; DKO) mice and examined whether the combined deletion of Prx4 and SOD1 aggravated NASH compared to single knockout. As to results, spontaneous liver damage characterized by caspase-3 activation and plasma ALT elevation was evident in the developing DKO mice, which showed increased incidence of premature death before adulthood. The double knockout mice fed with the MCD diet developed hepatic steatosis with further increase in plasma ALT. Then we explored nutritional factors that might ameliorate NASH using DKO mice. The liver damage was markedly attenuated by genistein, a soy isoflavone with antioxidant and anti-inflammatory properties. Thus, DKO mouse will be a useful animal model for studying NASH development and testing other potential treatments.
Soy Protein Research, Japan 20, 151-154, 2017.
Key words : oxidative stress, ER stress, SOD1, Prx4, genistein
Effects of Dietary Proteins during Lactation on the Skin in Mice Offspring
Takumi YAMANE*
Laboratory of Molecular Bioregulation, Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo 156-8502
ABSTRACT
The skin contains large amounts of extracellular matrix components such as collagen and hyaluronan, which protect the body from various external insults and retain moisture. Although it is well established that maternal protein nutrition is critical for infant physiology, little information is available on the effects of a dietary protein during lactation on the levels of collagen and hyaluronan in the skin of infant. In this study, we investigated effects of a dietary protein during lactation on the levels of type I tropocollagen, type III tropocollagen and hyaluronan in the skin of infant mice. C57BL/6 mice (10-11 weeks old) that were 15 days pregnant were fed a control diet (20% (w/w) casein) during gestation for 5 days. On the day of birth, dams were divided into 3 groups of 4 individuals [CO; 20% (w/w) casein, LP; 2% (w/w) casein and SOY; 2% (w/w) casein + 18% (w/w) soy protein] and fed for 15 days. The levels of type I tropocollagen and type III tropocollagen were decreased in the skin of infant mice from dams fed protein-restricted diet during lactation. No significant differences in the levels of hyaluronan were observed. These results show that protein-restricted diet during lactation decreases the levels of type I tropocollagen and type III tropocollagen in the skin of infant mice.
Soy Protein Research, Japan 20, 155-158, 2017.
Key words : skin, hyaluronan, collagen, lactation
Effect of Nitric Oxide Synthesis Inhibition on Soy Protein Diet-Induced Facilitation of Force Recovery in Muscles Undergoing Eccentric Contractions
Keita KANZAKI*1, Daiki WATANABE2, Yuki KAWAKAMI3, Yoshitaka TAKAHASHI3 and Masanobu WADA2
1Faculty of Health Science and Technology, Department of Clinical Nutrition, Kawasaki University of Medical Welfare, Kurashiki 701-0193
2Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima 739-8521
3Faculty of Health and Welfare Science, Department of Nutrition, Okayama Prefectural University, Soja 719-1197
ABSTRACT
We have shown that long-term intake of soy protein isolate (SPI) prevents protein degradation and facilitates force recovery in rat skeletal muscle exposed to repeated eccentric contractions (ECC). To assess underlying mechanisms, we investigated the effects of inhibition of nitric oxide synthesis on the force recovery with the SPI intake. Male Wistar rats were allowed free access to a 20% casein (control: CON) or SPI diet. Following a 3-weeks feeding period, left anterior crural muscles were exposed to 200-repeated ECC. The contralateral rested muscles were used as controls. Immediately after ECC, several rats fed the SPI were allowed to drink water containing an inhibitor of nitric oxide synthase, NG-Lnitro-arginine methyl ester (L-NAME, 75 mg/kg/day). Three days following ECC, isometric torque produced by the anterior muscles was measured and then tibialis anterior muscles were removed and used for biochemical analyses. SPI muscles had significantly lower torque deficits than CON and SPI+L-NAME muscles. Under resting conditions, nitrite/nitrate concentration and calpain-1 S-nitrosylation in the SPI muscle were significantly higher than that in the CON muscle. These enhancements were associated with suppression of increased autolysis of calpain-1 in SPI muscles subjected to ECC. These results suggest that the SPI intake induces nitrosylative inactivation of calpain and this may contribute to facilitate the force recovery after ECC.
Soy Protein Research, Japan 20, 159-164, 2017.
Key words : soy protein isolate, eccentric contraction, nitric oxide, calpain
The Association between Dietary Consumption and Cognitive Function According to Equol Productivity in Japanese Elderly; a Cross-Sectional Study
Mariko NAKAMOTO* and Tohru SAKAI
Department of Public Health and Applied Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503
ABSTRACT
Objectives: The purpose of this study was to compare the characteristics of dietary habits and cognitive function between equol producers and equol nonproducers in the elder Japanese population. Additionally, we assess the effect on cognitive function between higher soy intake group and lower soy intake group by equol producing capacity. Methods: Subjects comprised 4 men and 55 women aged 60-79 years. Cognitive function was assessed by the Mini-Mental State Examination. Dietary intake was assessed using a 3-day dietary record. Urinary equol concentrations were measured by the immunochromatography method, and participants with urinary equol levels > 1.0μM were defined as equol producers. Comparison of dietary intake and cognitive function between equol producers and equol non-producers were analysed using the independent t-test. The effect on cognitive function between higher soy intake group and lower soy intake group according to equol producing capacity was assess using the 2-way analysis of variance. Results: Number of subjects with equol producing capacity was 22 (37.3%). Regarding intake of food groups, equol producers ate higher potatoes, beans and fats and oils, and lower milks than equol non-producer. Especially among equol producers, cognitive function was higher in the higher miso intake group than in
lower miso intake group. Conclusions: Our results suggested that equol producers have different dietary characteristics from equol non-producers. Furthermore, there might be a different association between soy foods intake including miso, and cognitive function by equol producing capacity among Japanese elderly.
Soy Protein Research, Japan 20, 165-172, 2017.
Key words : dietary intake, cognitive function, equol productivity, elderly, a cross sectional study