Evolution of Olfactory Receptors Tuned to Mustard Oils in Herbivorous Drosophilidae.

The diversity of herbivorous insects is attributed to their propensity to specialize on toxic plants. In an evolutionary twist, toxins betray the identity of their bearers when herbivores coopt them as cues for host-plant finding, but the evolutionary mechanisms underlying this phenomenon are poorly understood. We focused on Scaptomyza flava, an herbivorous drosophilid specialized on isothiocyanate (ITC)-producing (Brassicales) plants, and identified Or67b paralogs that were triplicated as mustard-specific herbivory evolved. Using in vivo heterologous systems for the expression of olfactory receptors, we found that S. flava Or67bs, but not the homologs from microbe-feeding relatives, responded selectively to ITCs, each paralog detecting different ITC subsets. Consistent with this, S. flava was attracted to ITCs, as was Drosophila melanogaster expressing S. flava Or67b3 in the homologous Or67b olfactory circuit. ITCs were likely coopted as olfactory attractants through gene duplication and functional specialization (neofunctionalization and subfunctionalization) in S. flava, a recently derived herbivore.

Allyl isothiocyanate and 6-(methylsulfinyl) hexyl isothiocyanate contents vary among wild and cultivated wasabi (Eutrema japonium).

Wasabi (Japanese horseradish, Eutrema japonicum) is the only cultivated species in the genus Eutrema with functional components that provide a strong pungent flavor. To evaluate genetic resources for wasabi breeding, we surveyed variations in the two most abundant isothiocyanate (ITC) components in wasabi, allyl isothiocyanate (AITC) and 6-methylsulfinyl (hexyl) isothiocyanate (6-MSITC, hexaraphane). We also examined the phylogenetic relationships among 36 accessions of wild and cultivated wasabi in Japan using chloroplast DNA analysis. Our results showed that (i) the 6-MSITC content in currently cultivated wasabi accessions was significantly higher than in escaped cultivars, whereas the AITC content was not significantly different. (ii) Additionally, the 6-MSITC content in cultivated wasabi was significantly lower in the spring than during other seasons. This result suggested that the 6-MSITC content responds to environmental conditions. (iii) The phylogenetic position and the 6-MSITC content of accessions from Rebun, Hokkaido Prefecture had different profiles compared with those from southern Honshu, Japan, indicating heterogeneity of the Rebun populations from other Japanese wasabi accessions. (iv) The total content of AITC and 6-MSITC in cultivated wasabi was significantly higher than that of wild wasabi. In conclusion, old cultivars or landraces of wasabi, "zairai", are the most suitable candidates for immediate use as genetic resources.

Anti-Cancer Effects of Oxygen-Atom-Modified Derivatives of Wasabi Components on Human Leukemia Cells.

1-Isothiocyanato-6-(methylsulfinyl)-hexanate (6-MITC) is a natural compound found in Wasabia japonica. The synthetic derivatives 1-Isothiocyanato-6-(methylsulfenyl)-hexane (I7447) and 1-Isothiocyanato-6-(methylsulfonyl)-hexane (I7557) were obtained from 6-MITC by deleting and adding an oxygen atom to the sulfone group, respectively. We previously demonstrated that extensive mitotic arrest, spindle multipolarity, and cytoplasmic vacuole accumulation were induced by 6-MITC and inhibited the viability of human chronic myelogenous leukemia K562 cells. In this study, we examined the anti-cancer effects of 6-MITC derivatives on human chronic myelogenous leukemia (CML) cells. Autophagy was identified as the formation of autophagosomes with double-layered membranes using transmission electron microscopy. Cell cycle and differentiation were analyzed using flow cytometry. Apoptosis was detected by annexin V staining. After treatment with I7447 and I7557, the G2/M phase of cell cycle arrest was revealed. Cell death can be induced by a distinct mechanism (the simultaneous occurrence of autophagy and aberrant mitosis). The expression levels of acridine orange were significantly affected by lysosomal inhibitors. The natural wasabi component, 6-MITC, and its synthetic derivatives have similar effects on human chronic myelogenous leukemia cells and may be developed as novel therapeutic agents against leukemia.

Wasabi Component 6-(Methylsulfinyl)hexly Isothiocyanate and Derivatives Improve the Survival of Skin Allografts.

We tested the effect of 6-(Methylsulfinyl)hexyl Isothiocyanate (6-MITC) and derivatives (I7447 and I7557) on the differentiation and maturation of human myeloid dendritic cells (DCs) in vitro, and skin transplantation in vivo. Triggering of CD14+ myeloid monocyte development toward myeloid DCs with and without 6-MITC and derivatives to examine the morphology, viability, surface marker expression, and cytokine production. Stimulatory activity on allogeneic naive T cells was measured by proliferation and interferon-γ production. The skin allograft survival area model was used to translate the 6-MITC and derivatives' antirejection effect. All of the compounds had no significant effects on DC viability and reduced the formation of dendrites at concentrations higher than 10 µM. At this concentration, 6-MITC and I7557, but not I7447, inhibited the expression of CD1a and CD83. Both 6-MITC and I7557 exhibited T-cells and interferon-γ augmentation at lower concentrations and suppression at higher concentration. The 6-MITC and I7557 prolonged skin graft survival. Both the 6-MITC and I7557 treatment resulted in the accumulation of regulatory T cells in recipient rat spleens. No toxicity was evident in 6-MITC and I7557 treatment. The 6-MITC and I7557 induced human DC differentiation toward a tolerogenic phenotype and prolonged rat skin allograft survival. These compounds may be effective as immunosuppressants against transplant rejection.

Electrophile-Induced Conformational Switch of the Human TRPA1 Ion Channel Detected by Mass Spectrometry.

The human Transient Receptor Potential A1 (hTRPA1) ion channel, also known as the wasabi receptor, acts as a biosensor of various potentially harmful stimuli. It is activated by a wide range of chemicals, including the electrophilic compound N-methylmaleimide (NMM), but the mechanism of activation is not fully understood. Here, we used mass spectrometry to map and quantify the covalent labeling in hTRPA1 at three different concentrations of NMM. A functional truncated version of hTRPA1 (Δ1-688 hTRPA1), lacking the large N-terminal ankyrin repeat domain (ARD), was also assessed in the same way. In the full length hTRPA1, the labeling of different cysteines ranged from nil up to 95% already at the lowest concentration of NMM, suggesting large differences in reactivity of the thiols. Most important, the labeling of some cysteine residues increased while others decreased with the concentration of NMM, both in the full length and the truncated protein. These findings indicate a conformational switch of the proteins, possibly associated with activation or desensitization of the ion channel. In addition, several lysines in the transmembrane domain and the proximal N-terminal region were labeled by NMM, raising the possibility that lysines are also key targets for electrophilic activation of hTRPA1.

Identification and Characterization of Apigenin 6-C-Glucosyltransferase Involved in Biosynthesis of Isosaponarin in Wasabi (Eutrema japonicum).

Wasabi (Eutrema japonicum) is a perennial plant native to Japan that is used as a spice because it contains isothiocyanates. It also contains an isosaponarin, 4'-O-glucosyl-6-C-glucosyl apigenin, in its leaves, which has received increasing attention in recent years for its bioactivity, such as its promotion of type-I collagen production. However, its biosynthetic enzymes have not been clarified. In this study, we partially purified a C-glucosyltransferase (CGT) involved in isosaponarin biosynthesis from wasabi leaves and identified the gene coding for it (WjGT1). The encoded protein was similar to UGT84 enzymes and was named UGT84A57. The recombinant enzyme of WjGT1 expressed in Escherichia coli showed C-glucosylation activity toward the 6-position of flavones such as apigenin and luteolin. The enzyme also showed significant activity toward flavonols, but trace or no activity toward flavone 4'-O-glucosides, suggesting that isosaponarin biosynthesis in wasabi plants would proceed by 6-C-glucosylation of apigenin, followed by its 4'-O-glucosylation. Interestingly, the enzyme showed no activity against sinapic acid or p-coumaric acid, which are usually the main substrates of UGT84 enzymes. The accumulation of WjGT1 transcripts was observed mainly in the leaves and flowers of wasabi, in which C-glucosylflavones were accumulated. Molecular phylogenetic analysis suggested that WjGT1 acquired C-glycosylation activity independently from other reported CGTs after the differentiation of the family Brassicaceae.

Involvement of ERK1/2-mediated ELK1/CHOP/DR5 pathway in 6-(methylsulfinyl)hexyl isothiocyanate-induced apoptosis of colorectal cancer cells.

6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC) is a major bioactive compound in Wasabi. Although 6-MSITC is reported to have cancer chemopreventive activities in rat model, the molecular mechanism is unclear. In this study, we investigated the anticancer mechanisms using two types of human colorectal cancer cells (HCT116 p53+/+ and p53-/-). 6-MSITC caused cell cycle arrest in G2/M phase and induced apoptosis in both types of cells in the same fashion. Signaling data revealed that the activation of ERK1/2, rather than p53, is recruited for 6-MSITC-induced apoptosis. 6-MSITC stimulated ERK1/2 phosphorylation, and then activated ERK1/2 signaling including ELK1 phosphorylation, and upregulation of C/EBP homologous protein (CHOP) and death receptor 5 (DR5). The MEK1/2 inhibitor U0126 blocked all of these molecular events induced by 6-MSITC, and enhanced the cell viability in both types of cells in the same manner. These results indicated that ERK1/2-mediated ELK1/CHOP/DR5 pathway is involved in 6-MSITC-induced apoptosis in colorectal cancer cells. Abbreviations: CHOP: C/EBP homologous protein; DR5: death receptor 5; ELK1: ETS transcription factor; ERK1/2: extracellular signal-regulated kinase 1/2; JNK: Jun-N-terminal kinase; MAPK: mitogen-activated protein kinase; MEK1/2: MAP/ERK kinase 1/2; 6-MSITC: 6-(methylsulfinyl)hexyl isothiocyanate; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; PARP: poly(ADP-ribose) polymerase.

Comparison of B0 versus B0 and B1 field inhomogeneity correction for glycosaminoglycan chemical exchange saturation transfer imaging.

PURPOSE: The study compares glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging of intervertebral discs corrected for solely B0 inhomogeneities or both B0 and B1 inhomogeneities. METHODS: Lumbar intervertebral discs of 20 volunteers were examined with T2-weighted and gagCEST imaging. Field inhomogeneity correction was performed with B0 correction only and with correction of both B0 and B1. GagCEST effects measured by the asymmetric magnetization transfer ratio (MTRasym) and signal-to-noise ratio (SNR) were compared between both methods. RESULTS: Significant higher MTRasym and SNR values were obtained in the nucleus pulposus using B0 and B1 correction compared with B0-corrected gagCEST. The GagCEST effect was significantly different in the nucleus pulposus compared with the annulus fibrosus for both methods. CONCLUSION: The B0 and B1 field inhomogeneity correction method leads to an improved quality of gagCEST imaging in IVDs compared with only B0 correction.

Differential Pharmacological Activities of Oxygen Numbers on the Sulfoxide Moiety of Wasabi Compound 6-(Methylsulfinyl) Hexyl Isothiocyanate in Human Oral Cancer Cells.

6-(methylsulfinyl) hexyl isothiocyanate (6-MITC) is a naturally occurring compound isolated from Wasabia japonica (wasabi). The synthetic derivatives, 6-(methylsulfenyl) hexyl isothiocyanate (I7447) and 6-(methylsulfonyl) hexyl isothiocyanate (I7557), were derived from 6-MITC with the deletion and addition of oxygen, respectively. We aimed to evaluate the effect of these synthetic compounds on human oral cancer cells, SAS and OECM-1. All three compounds (I7447, 6-MITC, and I7557) inhibited the viability of SAS and OECM-1 cells using MTT assay. Morphological observations showed various proportions of mitotic arrest and apoptosis in cells treated with these compounds. Cell cycle analysis revealed relatively abundant G2/M arrest in 6-MITC and I7557-treated cells, whereas sub-G1 accumulation was found in I7447-treated cells. In using phosphorylated histone H3 as a marker for mitosis, the addition of 6-MITC and I7557 (excluding I7447) could be shown to arrest cells during mitosis. In contrast, I7447 induced more prominent apoptosis than the 6-MITC or I7557 compounds. The down-regulated expression of the phosphorylated form of CHK1 and Cdc25c was noted in 6-MITC and I7557-treated cells. I7557 could sensitize SAS cells to death by radiation. The wasabi compound, 6-MITC, and its chemical derivatives with different numbers of oxygen may have differential pharmacological effects on human oral cancer cells.

Simultaneous mapping of water shift and B1 (WASABI)-Application to field-Inhomogeneity correction of CEST MRI data.

PURPOSE: Together with the development of MRI contrasts that are inherently small in their magnitude, increased magnetic field accuracy is also required. Hence, mapping of the static magnetic field (B0 ) and the excitation field (B1 ) is not only important to feedback shim algorithms, but also for postprocess contrast-correction procedures. METHODS: A novel field-inhomogeneity mapping method is presented that allows simultaneous mapping of the water shift and B1 (WASABI) using an off-resonant rectangular preparation pulse. The induced Rabi oscillations lead to a sinc-like spectrum in the frequency-offset dimension and allow for determination of B0 by its symmetry axis and of B1 by its oscillation frequency. RESULTS: Stability of the WASABI method with regard to the influences of T1 , T2 , magnetization transfer, and repetition time was investigated and its convergence interval was verified. B0 and B1 maps obtained simultaneously by means of WASABI in the human brain at 3 T and 7 T can compete well with maps obtained by standard methods. Finally, the method was applied successfully for B0 and B1 correction of chemical exchange saturation transfer MRI (CEST-MRI) data of the human brain. CONCLUSION: The proposed WASABI method yields a novel simultaneous B0 and B1 mapping within 1 min that is robust and easy to implement. Magn Reson Med 77:571-580, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Inhibitory effects of Japanese horseradish (Wasabia japonica) on the formation and genotoxicity of a potent carcinogen, acrylamide.

BACKGROUND: The formation of acrylamide (AA) in cooked foods has raised human health concerns. AA is metabolized by cytochrome P450 2E1 (CYP2E1) to glycidamide (GA), which forms DNA adducts. This study examined the inhibitory effects of wasabi (Japanese horseradish, Wasabia japonica) roots and leaves as well as their active component, allyl isothiocyanate (AIT), on the formation and genotoxicity of AA. RESULTS: AA formation (51.8 ± 4.2 µg kg-1 ) was inhibited with ≥2 mg mL-1 of AIT. Wasabi roots also inhibited AA formation (∼90% reduction), but wasabi leaves were not effective at 2 mg mL-1 . Wasabi roots and leaves decreased the number of cells with micronuclei by approximately 33 and 24% respectively compared with the AA treatment group. Moreover, wasabi roots and leaves (100 mg kg-1 body weight (BW) day-1 for each) decreased AA (100 mg kg-1 BW day-1 )-induced DNA damage. The AA-induced CYP2E1 activity was decreased by 39 and 26% with wasabi roots and leaves respectively. Further, the activity of glutathione S-transferase, which catalyzes the detoxification of AA via glutathione conjugation, increased by 54 and 33% with wasabi roots and leaves respectively. CONCLUSION: These results indicate that wasabi roots and leaves are effective ingredients for inhibiting the formation and genotoxicity of AA. © 2016 Society of Chemical Industry.

Wasabi leaf extracts attenuate adipocyte hypertrophy through PPARγ and AMPK.

Hypertrophy of adipocytes in obese adipose tissues causes metabolic abnormality by adipocytokine dysregulation, which promotes type 2 diabetes mellitus, hypertension, and dyslipidemia. We investigated the effects of wasabi (Wasabia japonica Matsum) leaf extracts on metabolic abnormalities in SHRSP.Z-Leprfa/IzmDmcr rats (SHRSP/ZF), which are a model of metabolic syndrome. Male SHRSP/ZF rats aged 7 weeks were divided into two groups: control and wasabi leaf extract (WLE) groups, which received water or oral treatment with 4 g/kg/day WLE for 6 weeks. WLE improved the body weight gain and high blood pressure in SHRSP/ZF rats, and the plasma triglyceride levels were significantly lower in the WLE group. Adipocyte hypertrophy was markedly prevented in adipose tissue. The expression of PPARγ and subsequent downstream genes was suppressed in the WLE group adipose tissues. Our data suggest that WLE inhibits adipose hypertrophy by suppressing PPARγ expression in adipose tissue and stimulating the AMPK activity by increased adiponectin.

Management of Meloidogyne incognita on tomato with endophytic bacteria and fresh residue of Wasabia japonica.

AIMS: To characterize the nematicidal endophytic bacteria (NEB) of Wasabia japonica (wasabi) and evaluated the control efficacies of promising NEB as well as fresh wasabi residue (FWR) against Meloidogyne incognita on tomato. METHODS AND RESULTS: By in vitro bioassay, 53 NEB strains showing nematicidal efficacies of >50% against J2 of M. incognita were isolated from wasabi. Basing on 16S rRNA gene sequences, these NEB were identified into 18 species of 11 genera. In greenhouse, incorporation of selected NEB culture or FWR into potted soil significantly reduced infection of M. incognita on tomato. Treating tomatoes with either FWR or NEB of Raoultella terrigena RN16 and Pseudomonas reinekei SN21 in the field yielded excellent control efficacies against M. incognita, especially the combinations of FWR with either R. terrigena RN16 or Ps. reinekei SN21 at doses of 50 g plus 100 ml per plant or more. CONCLUSIONS: The results established that R. terrigena RN16 and Ps. reinekei SN21 applied separately or combined with FWR have the potential to provide bioprotection agents against M. incognita. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides novel way for disease management using combination of endophyte and host residue.

Characterization of unique EDTA-insensitive methylthioalkylmalate synthase from Eutrema japonicum and its potential application in synthetic biology.

6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC), a derivative of glucosinolate with a six-carbon chain, is a compound found in wasabi and has diverse health-promoting properties. The biosynthesis of glucosinolates from methionine depends on a crucial step catalyzed methylthioalkylmalate synthases (MAMs), which are responsible for the generation of glucosinolates with varying chain lengths. In this study, our primary focus was the characterization of two methylthioalkyl malate synthases, MAM1-1 and MAM1-2, derived from Eutrema japonicum, commonly referred to as Japanese wasabi. Eutremajaponicum MAMs (EjMAMs) were expressed in an Escherichiacoli expression system, subsequently purified, and in vitro enzymatic activity was assayed. We explored the kinetic properties, optimal pH conditions, and cofactor preferences of EjMAMs and compared them with those of previously documented MAMs. Surprisingly, EjMAM1-2, categorized as a metallolyase family enzyme, displayed 20% of its maximum activity even in the absence of divalent metal cofactors or under high concentrations of EDTA. Additionally, we utilized AlphaFold2 to generate structural homology models of EjMAMs, and used in silico analysis and mutagenesis studies to investigate the key residues participating in catalytic activity. Moreover, we examined in vivo biosynthesis in E. coli containing Arabidopsis thaliana branched-chain amino acid transferase 3 (AtBCAT3) along with AtMAMs or EjMAMs and demonstrated that EjMAM1-2 exhibited the highest conversion rate among those MAMs, converting l-methionine to 2-(2-methylthio) ethyl malate (2-(2-MT)EM). EjMAM1-2 shows a unique property in vitro and highest activity on converting l-methionine to 2-(2-MT)EM in vivo which displays high potential for isothiocyanate biosynthesis in E. coli platform.

Wasabi Gone Wild? Origin and Characterization of the Complete Plastomes of Ulleung Island Wasabi (Eutrema japonicum; Brassicaceae) and Other Cultivars in Korea.

Korean wasabi occurs naturally on the young oceanic, volcanic Ulleung Island off the east coast of the Korean Peninsula. Although the Ulleung Island wasabi is reported as Eutrema japonicum and has been suggested to be morphologically identical to cultivars in Korea, very little is known about its taxonomic identity and relationship with other cultivars. In this study, we sequenced the complete chloroplast DNA sequences of three naturally occurring Ulleung Island wasabi plants and six cultivars ('Daewang', 'Daruma', 'Micado', 'Orochi', 'Green Thumb', and 'Shogun') from continental Korea and determined the taxonomic identity of Korean wasabi on Ulleung Island. The size and organization of the complete chloroplast genomes of the nine accessions were nearly identical to those of previously reported wasabi cultivars. In addition, phylogenetic analysis based on the complete plastomes suggested that Ulleung Island wasabi most likely comprises various wasabi cultivars with three chlorotypes ('Shogun', 'Green Thumb', and a unique Chusan type). Based on the complete plastomes, we identified eight chlorotypes for the major wasabi cultivars and the Ulleung Island wasabi. Two major groups (1-'Mazuma' and 'Daruma', and 2-'Fujidaruma'/'Shimane No. 3'/Ulleung Island wasabi/five cultivars in Korea) were also identified based on mother line genealogical history. Furthermore, different types of variations (mutations, insertions/deletions (indels), mononucleotide repeats, and inversions) in plastomes were identified to distinguish different cultivar lines and five highly divergent hotspots. The nine newly obtained complete plastomes are valuable organelle genomic resources for species identification and infraspecific phylogeographic studies on wild and cultivated wasabi.

Determination of the Optimal Concentration of Natural Antimicrobial Agents in Marinade Sauce for Meal Kits.

This study aimed to determine the antimicrobial effectiveness of natural antimicrobial agents (NAAs) (yuzu juice, wasabi extract, and rosemary extract) against three target microorganisms (TMs) (Escherichia coli, Staphylococcus aureus, and Salmonella Typhimurium) and to determine the optimal concentration of these agents using response surface methodology (RSM) to ensure the safety of meal kits manufactured using marinade sauce. The three NAAs added to marinade sauce effectively inactivated TMs (P<0.05), in particular, yuzu juice had the greatest antimicrobial effect against TMs, followed by wasabi and rosemary extracts. To determine the optimal concentration of NAAs using RSM, 17 concentrations were tested with three TMs as dependent variables and three NAAs as independent variables. The results showed that E. coli was not present under any of the conditions tested, whereas S. aureus and S. Typhimurium exhibited different characteristics depending on the conditions. Through response surface analysis of the TMs except for E. coli, which was not detected, it was determined that S. aureus had a coefficient of determination (R2) of 0.928 and a lack of fit of 0.074, and the linear regression of [yuzu juice] (X1) and quadratic regression of [yuzu juice]2 (X12) were both significant (P<0.05). S. Typhimurium had an R2 of 0.8955 and a lack of fit of 0.051, and only the quadratic regression of [yuzu juice]2 (X12) was significant (P<0.05). Based on RSM and ridge analysis, the optimal mixed conditions were determined to be 3.92% (v/w) yuzu juice, 23.41% (v/w) wasabi extract, and 3.93% (v/w) rosemary extract. After investigating the antimicrobial effect under the optimal conditions, E. coli and S. Typhimurium were absent, and S. aureus was reduced to 2.50 ± 0.09 log colony-forming units/g after 24 h. The results indicated that mixed treatment with the three NAAs had a more significant antimicrobial effect due to their synergistic properties compared to when used in isolation.

Immunomodulatory Effects and Regulatory Mechanisms of (R)-6-HITC, an Isothiocyanate from Wasabi (Eutrema japonicum), in an Ex Vivo Mouse Model of LPS-Induced Inflammation.

The present study aimed to investigate the effects of (R)-(-)-1-isothiocyanato-6-(methylsulfinyl)-hexane [(R)-6-HITC], the major isothiocyanate present in wasabi, in an ex vivo model of inflammation using lipopolysaccharide-stimulated murine peritoneal macrophages. (R)-6-HITC improved the immune response and mitigated oxidative stress, which involved suppression of reactive oxygen species, nitric oxide, and pro-inflammatory cytokines (IL-1ß, IL-6, IL-17, IL-18, and TNF-α) production and downregulation of pro-inflammatory enzymes such as inducible nitric oxide synthase, COX-2, and mPGES-1. In addition, (R)-6-HITC was able to activate the Nrf2/HO-1 axis while simultaneously inhibiting key signaling pathways, including JAK2/STAT3, mitogen-activated protein kinases, and canonical and noncanonical inflammasome pathways, orchestrating its potent immunomodulatory effects. Collectively, these findings demonstrate the potential of (R)-6-HITC as a promising nutraceutical for the management of immuno-inflammatory diseases and justify the need for further in vivo validation studies.

Effect of adding various supplements on physicochemical properties and starch digestibility of cooked rice.

This study investigated the physicochemical modifications of cooked rice caused by adding various supplements (rapeseed oil, dried wasabi powder, and dried chili pepper powder). The physicochemical and digestive properties of treated cooked rice were analyzed using multiple techniques to determine the impact of supplements on the rice quality, including its starch digestibility. All samples with added supplements showed an increase in surface firmness (0.77-0.95 kg·m/s2 (N)) and a decrease in thickness (2.23-2.35 mm) and surface adhesiveness (1.43-7.22 J/m3). Compared to the control group, two absorption peaks at 2856 and 1748 cm-1 and new signals at 1683 and 1435 cm-1 appeared in the Fourier transform infrared (FTIR) spectroscopy. Analysis of FTIR results revealed that the interaction force was mainly through noncovalent interactions. Moreover, adding supplements increased the resistant starch (RS) levels in all samples. Scanning electron microscopy (SEM) suggested that oil-enriched phases, proteins, and polyphenols could cause large agglomeration and loose gel structure. These results suggested the formation of amylose-guest molecule complexes, which may influence starch functionality. Our work could provide insight into the starch-supplement interactions and the key factors affecting starch digestibility.

Screening for Fungicide Efficacy in Controlling Blackleg Disease in Wasabi (Eutrema japonicum).

Blackleg disease is devastating for wasabi (Eutrema japonicum) production, occurring at any time and everywhere within the main production area of the Sichuan Province, China. There have been very few studies on the chemical control of this disease. In this study, we isolated and identified a local popular strain of the pathogen Plenodomus wasabiae. The isolated fungus strain caused typical disease spots on the leaves and rhizomes upon inoculation back to wasabi seedlings. The symptoms of blackleg disease developed very quickly, becaming visible on the second day after exposure to P. wasabiae and leading to death within one week. We then evaluated the efficacy of ten widely used fungicides to screen out effective fungicides. The efficacy of the tested fungicides was determined through mycelial growth inhibition on medium plates. As a result, tebuconazole and pyraclostrobin were able to inhibit the mycelial growth of P. wasabiae, and the most widely used dimethomorph in local production areas produced the lowest inhibition activity (13.8%). Nevertheless, the highest control efficacy of tebuconazole and pyraclostrobin on wasabi seedlings was only 47.48% and 39.03%, respectively. Generally, the control efficacy of spraying the fungicide before inoculation was better than that after inoculation. An increase in the application concentration of the two fungicides did not proportionately result in improved performance. We cloned the full-length sequence of sterol 14-demethylase (CYP51) and cytochrome B (CYTB) of which the mutations may contribute to the possible antifungalresistance. These two genes of the isolated fungus do not possess any reported mutations that lead to fungicide resistance. Previous studies indicate that there is a significant difference between fungicides in terms of the effectiveness of controlling blackleg disease; however, the control efficacy of fungicides is limited in blackleg control. Therefore, field management to prevent wound infection and unfavorable environmental conditions are more important than pesticide management.

Benefits of Wasabi Supplements with 6-MSITC (6-Methylsulfinyl Hexyl Isothiocyanate) on Memory Functioning in Healthy Adults Aged 60 Years and Older: Evidence from a Double-Blinded Randomized Controlled Trial.

BACKGROUND: Cognitive functions decline with age. Declined cognitive functions negatively affect daily behaviors. Previous studies showed the positive effect of spices and herbs on cognition. In this study, we investigated the positive impact of wasabi, which is a traditional Japanese spice, on cognitive functions. The main bioactive compound of wasabi is 6-MSITC (6 methylsulfinyl hexyl isothiocyanate), which has anti-oxidant and anti-inflammatory functions. Anti-oxidants and anti-inflammatories have an important role in cognitive health. Therefore, 6-MSITC is expected to have positive effects on cognitive function. Previous studies showed the beneficial effects on cognitive functions in middle-aged adults. However, it is unclear that 6-MSITC has a positive effect on cognitive functions in healthy older adults aged 60 years and over. Here, we investigated whether 12 weeks' 6-MSITC intervention enhances cognitive performance in older adults using a double-blinded randomized controlled trial (RCT). METHODS: Seventy-two older adults were randomly assigned to 6-MSITC or placebo groups. Participants were asked to take a supplement (6-MSITC or a placebo) for 12 weeks. We checked a wide range of cognitive performances (e.g., executive function, episodic memory, processing speed, working memory, and attention) at the pre- and post-intervention periods. RESULTS: The 6-MSITC group showed a significant improvement in working and episodic memory performances compared to the placebo group. However, we did not find any significant improvements in other cognitive domains. DISCUSSION: This study firstly demonstrates scientific evidence that 6-MSITC may enhance working memory and episodic memory in older adults. We discuss the potential mechanism for improving cognitive functions after 6-MSITC intake.