Stochastic resonance in sparse neuronal network: functional role of ongoing activity to detect weak sensory input in awake auditory cortex of rat.

The awake cortex is characterized by a higher level of ongoing spontaneous activity, but it has a better detectability of weak sensory inputs than the anesthetized cortex. However, the computational mechanism underlying this paradoxical nature of awake neuronal activity remains to be elucidated. Here, we propose a hypothetical stochastic resonance, which improves the signal-to-noise ratio (SNR) of weak sensory inputs through nonlinear relations between ongoing spontaneous activities and sensory-evoked activities. Prestimulus and tone-evoked activities were investigated via in vivo extracellular recording with a dense microelectrode array covering the entire auditory cortex in rats in both awake and anesthetized states. We found that tone-evoked activities increased supralinearly with the prestimulus activity level in the awake state and that the SNR of weak stimulus representation was optimized at an intermediate level of prestimulus ongoing activity. Furthermore, the temporally intermittent firing pattern, but not the trial-by-trial reliability or the fluctuation of local field potential, was identified as a relevant factor for SNR improvement. Since ongoing activity differs among neurons, hypothetical stochastic resonance or "sparse network stochastic resonance" might offer beneficial SNR improvement at the single-neuron level, which is compatible with the sparse representation in the sensory cortex.

Impact of an artificial intelligence-aided endoscopic diagnosis system on improving endoscopy quality for trainees in colonoscopy: Prospective, randomized, multicenter study.

OBJECTIVE: This study was performed to evaluate whether the use of CAD EYE (Fujifilm, Tokyo, Japan) for colonoscopy improves colonoscopy quality in gastroenterology trainees. METHODS: The patients in this multicenter randomized controlled trial were divided into Group A (observation using CAD EYE) and Group B (standard observation). Six trainees performed colonoscopies using a back-to-back method in pairs with gastroenterology experts. The primary end-point was the trainees' adenoma detection rate (ADR), and the secondary end-points were the trainees' adenoma miss rate (AMR) and Assessment of Competency in Endoscopy (ACE) tool scores. Each trainee's learning curve was evaluated using a cumulative sum (CUSUM) control chart. RESULTS: We analyzed data for 231 patients (Group A, n = 113; Group B, n = 118). The ADR was not significantly different between the two groups. Group A had a significantly lower AMR (25.6% vs. 38.6%, P = 0.033) and number of missed adenomas per patient (0.5 vs. 0.9, P = 0.004) than Group B. Group A also had significantly higher ACE tool scores for pathology identification (2.26 vs. 2.07, P = 0.030) and interpretation and identification of pathology location (2.18 vs. 2.00, P = 0.038). For the CUSUM learning curve, Group A showed a trend toward a lower number of cases of missed multiple adenomas by the six trainees. CONCLUSION: CAD EYE did not improve ADR but decreased the AMR and improved the ability to accurately locate and identify colorectal adenomas. CAD EYE can be assumed to be beneficial for improving colonoscopy quality in gastroenterology trainees. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (UMIN000044031).

Baloxavir treatment of ferrets infected with influenza A(H1N1)pdm09 virus reduces onward transmission.

Influenza viruses cause seasonal outbreaks and pose a continuous pandemic threat. Although vaccines are available for influenza control, their efficacy varies each season and a vaccine for a novel pandemic virus manufactured using current technology will not be available fast enough to mitigate the effect of the first pandemic wave. Antivirals can be effective against many different influenza viruses but have not thus far been used extensively for outbreak control. Baloxavir, a recently licensed antiviral drug that targets the influenza virus endonuclease, has been shown to reduce virus shedding more effectively than oseltamivir, a widely used neuraminidase inhibitor drug. Thus it is possible that treatment with baloxavir might also interrupt onward virus transmission. To test this, we utilized the ferret model, which is the most commonly used animal model to study influenza virus transmission. We established a subcutaneous baloxavir administration method in ferrets which achieved similar pharmacokinetics to the approved human oral dose. Transmission studies were then conducted in two different locations with different experimental setups to compare the onward transmission of A(H1N1)pdm09 virus from infected ferrets treated with baloxavir, oseltamivir or placebo to naïve sentinel ferrets exposed either indirectly in adjacent cages or directly by co-housing. We found that baloxavir treatment reduced infectious viral shedding in the upper respiratory tract of ferrets compared to placebo, and reduced the frequency of transmission amongst sentinels in both experimental setups, even when treatment was delayed until 2 days post-infection. In contrast, oseltamivir treatment did not substantially affect viral shedding or transmission compared to placebo. We did not detect the emergence of baloxavir-resistant variants in treated animals or in untreated sentinels. Our results support the concept that antivirals which decrease viral shedding could also reduce influenza transmission in the community.

Efficient method for generating citrus hybrids with polyembryonic Satsuma mandarin as the female parent.

Many citrus fruits have polyembryonic traits, and their seeds contain many nucellar embryos along with a single zygotic embryo, affecting the crossbreeding process. Generally, nucellar embryos are considered to have more vigorous growth than zygotic embryos. Therefore, the in vitro method using an embryo rescue culture is often chosen to obtain zygotic embryo-derived individuals. Nevertheless, hybrids can be obtained with a certain probability from the seeds sown in the soil. The in-soil method, which sows seeds in the soil, has distinct advantages over the in vitro method, including lower cost and simpler technology. However, the efficiency of obtaining hybrids from these methods has not been compared in detail. The current study evaluates the effectiveness of these methods for obtaining hybrids using polyembryonic Satsuma mandarin as the female parent. The number of mature embryos per seed using the in-soil method was less than one-third of that produced using the in vitro method. Although the in vitro method produced more hybrids than the in-soil method, the ratio of the hybrids to the resulting population was significantly higher in the in-soil method. Thus, the in-soil method was more efficient and practical than the in vitro method for selecting hybrids from polyembryonic Satsuma mandarin seeds. The observations of the individuals obtained using the in-soil method suggest that zygotic embryos were not poorer in growth than nucellar embryos when using our selected parental combinations. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01324-6.

Efficacy of elobixibat as bowel preparation agent for colonoscopy: Prospective, randomized, multi-center study.

BACKGROUND AND AIM: Elobixibat is a novel ileal bile acid transporter inhibitor. This study aimed to compare the efficacy, tolerability, and safety of the combination of elobixibat and 1 L of polyethylene glycol formulation containing ascorbic acid (PEG-Asc) solution versus the combination of sodium picosulfate and 1-L PEG-Asc solution as bowel preparation for colonoscopy. METHODS: This multi-center, randomized, observer-blinded, non-inferiority study recruited 210 outpatients who were assigned to either the elobixibat plus 1-L PEG-Asc group (group A) or the sodium picosulfate plus 1-L PEG-Asc group (group B). The quality of the bowel cleansing level was assessed by the Boston Bowel Preparation Scale (BBPS) and compared the bowel cleansing level between the groups. Data regarding bowel preparation time, patients' tolerability, and adverse events were also analyzed. RESULTS: Data for 196 patients (99 in group A and 97 in group B) were analyzed finally. BBPS was comparable between group A and B (8.3 ± 0.9 vs. 8.3 ± 0.7; P = 0.88). Consequently, the adequate bowel preparation rate in groups A and B was 95.0% and 99.0%, respectively (-4.0%, 95% CI -9.3 to 1.5). Bowel preparation time in group A was similar to that in group B (348.2 ± 79.8 min vs. 330.8 ± 82.5 min; P = 0.13), whereas, sleep disturbance was significantly less frequent in group A than in group B (10.2% vs. 22.7%; P = 0.02). CONCLUSIONS: The combination of elobixibat and 1-L PEG-Asc can be considered an alternative bowel preparation for colonoscopy considering the equivalent bowel cleansing effect and less frequent sleep disturbance. The Japan Registry of Clinical Trials (jRCTs41180026).

Physicochemical Properties and In Vitro Digestibility of Starch from a Trace-Rutinosidase Variety of Tartary Buckwheat 'Manten-Kirari'.

We recently developed a novel Tartary buckwheat variety, 'Manten-Kirari', with trace-rutinosidase activity. The use of 'Manten-Kirari' enabled us to make rutin-rich food products with low bitterness. This study was intended to evaluate the physicochemical properties and in vitro digestibility of starch isolated from 'Manten-Kirari'. For comparison, the representative common buckwheat variety 'Kitawasesoba' and Tartary buckwheat variety 'Hokkai T8' in Japan were also used. The lowest content of amylose was found in 'Manten-Kirari' starch (18.1%) while the highest was in 'Kitawasesoba' starch (22.6%). 'Manten-Kirari' starch exhibited a larger median granule size (11.41 µm) and higher values of peak viscosity (286.8 RVU) and breakdown (115.2 RVU) than the others. The values of onset temperature for gelatinization were 60.5 °C for 'Kitawasesoba', 61.3 °C for 'Manten-Kirari', and 64.7 °C for 'Hokkai T8'. 'Manten-Kirari' and 'Hokkai T8' starches were digested more slowly than 'Kitawasesoba' starch. Our results will provide fundamental information concerning the expanded use of 'Manten-Kirari' in functional foods.

Gastrointestinal adverse reactions reduce the success rate of Helicobacter pylori eradication therapy: A multicenter prospective cohort study.

BACKGROUND: The screening and treatment of Helicobacter pylori infection for all junior high students in Saga Prefecture, Japan, were started in 2016. The present study aims to evaluate the influence of adverse reactions on the success of the eradication therapy. METHODS: From 2017 to 2019, 25,006 third-grade junior high school students were tested for urinary anti-H. pylori antibodies. Positive cases were confirmed by H. pylori stool antigen tests. Of the 531 students who were found to be H. pylori-positive, 390 (358 in first-line and 32 in second-line therapy) underwent eradication therapy, and 274 (242 in first-line and 32 in second-line) students actually completed a self-reported form to rate stool consistency (based on the Bristol Stool Scale), the maximum number of bowel movements, and abdominal symptoms during the 7 days of treatment. RESULTS: Among the 274 students, the total of primary and secondary eradication success rates was 87% (95% confidential interval: 82.9-90.1) in intention-to-treat analysis. On days 4, 5, and 6, stool consistency was looser in the primary eradication failure group than in the success group (p < .05). Looser stool consistencies were observed in male students with abdominal pain compared to those who did not experience pain (p < .05). Abdominal pain and diarrhea were detected in 28.5% and 42.7% of the subjects, respectively. The overall incidence of other adverse events was low (n = 8/274, 2.9%), and only two students discontinued treatment because of adverse events. CONCLUSIONS: Softening of the stool was related to the eradication failure in the junior high school students, especially in males with abdominal pain. Adverse effects did not induce discontinuation of the eradication treatment.

Potential application of simple easy-to-use insertion-deletion (InDel) markers in citrus cultivar identification.

We previously developed insertion-deletion (InDel) markers that distinguish three genotypes (two homozygous and one heterozygous) of diverse citrus cultivars. These InDel markers were codominant and could be clearly detected by using simple agarose gel electrophoresis. We sought to establish a method for cultivar identification using these 28 InDel markers to genotype 31 citrus cultivars. The results revealed that a minimum of 6 markers were required to identify individuals using the three-genotype classification method. Furthermore, we found that a simple method for distinguishing between two genotypes (homozygous and heterozygous) could be used to identify individuals using a minimum of 7 markers. Our findings provide a basis for the development of simple and rapid citrus cultivar identification methods.

Risk Factors for Post-Endoscopic Retrograde Pancreatography Pancreatitis: A Retrospective Chart Review in a Regional Hospital in Japan.

BACKGROUND: Endoscopic retrograde pancreatography (ERCP) is sometimes complicated by post-ERCP pancreatitis (PEP), which is a severe adverse effect. OBJECTIVE: The present study was performed to (i) evaluate the risk factors for PEP and (ii) compare the risk of PEP after ERCP performed in the off hours versus regular hours. METHODS: This retrospective study included 374 patients who underwent ERCP from January 2013 to December 2017. Among these patients, 38 (10.2%) developed PEP. The potential risk factors for PEP were evaluated by multivariate regression analysis, and the risk of PEP was compared between ERCP performed during regular hours and off hours. RESULTS: The independent risk factors for PEP were a relatively younger age (<75 years; p = 0.024), female sex (p = 0.002), a history of pancreatitis (p = 0.044), and performance of pancreatography (p = 0.010). Use of a diclofenac suppository and performance of pancreatic stenting were not preventive for PEP after ERCP. The complication rate of PEP did not differ between ERCP performed during the off hours versus regular hours. CONCLUSIONS: A relatively younger age (<75 years), female sex, a history of pancreatitis, and performance of pancreatography were potential risk factors for PEP, whereas the risk of PEP was not different between ERCP performed during the off hours versus regular hours.

An Investigation of Nine Patients with Gastrointestinal Immune-Related Adverse Events Caused by Immune Checkpoint Inhibitors.

INTRODUCTION/AIMS: Immune checkpoint inhibitors (ICIs) sometimes cause immune-related adverse events (irAEs), of which there is little information in the literatures. The objective of this study was to characterize the clinical features of gastrointestinal irAEs (GI irAEs). MATERIALS AND METHODS: From a total of 250 patients who were administered anti-PD-1 antibodies (nivolumab and pembrolizumab), we retrospectively identified 9 patients with grade 2 or higher GI irAE based on medical records. Patient characteristics, clinical features, imaging and pathological findings, and treatment course were evaluated. RESULTS: Grade 2 or higher GI irAEs were observed in 9 (3.6%) patients. Of the 9 patients who experienced GI irAE, 8 were male, and mean age was 63.2 years. Five patients received nivolumab and 4 received pembrolizumab. The GI irAEs observed were diarrhea in 7 patients and bloody stool in 2 patients. Grade 2 GI irAEs were identified in 3 patients and grade 3 GI irAEs in 6 patients. The average time from ICI administration to the onset of GI irAEs was 22.2 weeks (range 7-56 weeks) for nivolumab and 19.7 weeks (range 11-28 weeks) for pembrolizumab. Endoscopic findings showed ulcerative colitis-like findings in 3 of 7 patients, and pathological examination revealed crypt epithelial cell apoptosis in 6 of 7 patients. Eight of the 9 patients received steroids, and 2 patients received infliximab additionally. All GI irAEs were manageable. CONCLUSIONS: Because of the lack of specific clinical, imaging, and pathological findings, information of ICI use was indispensable for diagnosis. Although GI irAEs are controllable by steroid and infliximab, further studies regarding management strategy will be needed.

Present status and future perspectives of breeding for buckwheat quality.

Buckwheat is an important crop globally. It has been processed into cereal grain, noodles, confectionery, bread, and fermented foods for many years. Buckwheat production and processing has supported local economies and is deeply related to the culture of some regions. Buckwheat has many unique traits as a food, with a good flavor and color. In addition, buckwheat is also a healthy food because it contains bioactive compounds that have anti-oxidative, anti-hypertensive, and anti-obesity properties. Therefore, breeding of buckwheat for quality is an important issue to be addressed. Compared to other crops, there is still a lack of basic information on quality, including bioactive compounds generation and enhancement. However, some mechanisms for modifying and improving the quality of buckwheat varieties have recently been identified. Further, some varieties with improved quality have recently been developed. In this review, we summarize the issues around buckwheat quality and review the present status and future potential of buckwheat breeding for quality.

Combination treatment with the cap-dependent endonuclease inhibitor baloxavir marboxil and a neuraminidase inhibitor in a mouse model of influenza A virus infection.

OBJECTIVES: Baloxavir marboxil (formerly S-033188) is a first-in-class, orally available, cap-dependent endonuclease inhibitor licensed in Japan and the USA for the treatment of influenza virus infection. We evaluated the efficacy of delayed oral treatment with baloxavir marboxil in combination with a neuraminidase inhibitor in a mouse model of lethal influenza virus infection. METHODS: The inhibitory potency of baloxavir acid (the active form of baloxavir marboxil) in combination with neuraminidase inhibitors was tested in vitro. The therapeutic effects of baloxavir marboxil and oseltamivir phosphate, or combinations thereof, were evaluated in mice lethally infected with influenza virus A/PR/8/34; treatments started 96 h post-infection. RESULTS: Combinations of baloxavir acid and neuraminidase inhibitor exhibited synergistic potency against viral replication by means of inhibition of cytopathic effects in vitro. In mice, baloxavir marboxil monotherapy (15 or 50 mg/kg twice daily) significantly and dose-dependently reduced virus titre 24 h after administration and completely prevented mortality, whereas oseltamivir phosphate treatments were not as effective. In this model, a suboptimal dose of baloxavir marboxil (0.5 mg/kg twice daily) in combination with oseltamivir phosphate provided additional efficacy compared with monotherapy in terms of virus-induced mortality, elevation of cytokine/chemokine levels and pathological changes in the lung. CONCLUSIONS: Baloxavir marboxil monotherapy with 96 h-delayed oral dosing achieved drastic reductions in virus titre, inflammatory response and mortality in a mouse model. Combination treatment with baloxavir acid and oseltamivir acid in vitro and baloxavir marboxil and oseltamivir phosphate in mice produced synergistic responses against influenza virus infections, suggesting that treating humans with the combination may be beneficial.

Correlation of Barrett's esophagus with colorectal polyps in Japanese patients: A retrospective chart review.

BACKGROUND AND AIM: Barrett's esophagus and colorectal polyps have several overlapping risk factors. Whereas several reports in Western countries have indicated a close relationship between Barrett's esophagus and colorectal polyps, the relationship between these two diseases remains unclear in Japan. This study was performed to determine whether the prevalence of Barrett's esophagus is related to that of colorectal polyps in Japanese patients. METHODS: The present retrospective chart review included 1582 Japanese patients who underwent both total colonoscopy and esophagogastroduodenoscopy from January 2010 to December 2016. The data on colorectal polyps and Barrett's esophagus were obtained from the endoscopic findings. The medical record of each patient was checked for age, sex, body mass index, smoking, alcohol drinking, use of acid suppression agents, and comorbidities including a history of diabetes, ischemic heart disease, gastroesophageal reflux disease, hiatal hernia, and Helicobacter pylori infection. RESULTS: Colorectal polyps were detected in 789 of the 1582 patients (49.9%). Barrett's esophagus was detected in 233 patients (14.7%), and most cases of Barrett's esophagus (n = 229) were classified as short-segment Barrett's esophagus. Colorectal polyps were more frequent in patients with than without Barrett's esophagus (odds ratio, 1.79; 95% confidence interval, 1.31-2.46; P < 0.001). In addition to Barrett's esophagus, the data indicated that old age, male sex, obesity, smoking, alcohol drinking, diabetes mellitus, and ischemic heart disease were independent risk factors for colorectal polyps. CONCLUSIONS: The present study revealed the correlation between the prevalence of Barrett's esophagus and colorectal polyps in Japanese patients.

Physicochemical properties of potato starches manufactured in Hokkaido factories.

Potato starch is an important agricultural product in Hokkaido, the northernmost island of Japan, with output of around 0.18 million tons/year. The present investigation was conducted to evaluate the physicochemical properties of potato starch samples manufactured in 10 factories in Hokkaido. The starch samples were analyzed for pasting properties by rapid visco analyzer (RVA), gelatinization properties by differential scanning calorimetry (DSC), color components, and minerals, amylose, and resistant starch (RS) contents. The phosphorus and potassium contents of potato starches averaged 746 ppm and 681 ppm, ranging from 669 to 835 ppm and from 481 to 803 ppm, respectively. Relatively wide ranges were noted in the contents of sodium (35-134 ppm), magnesium (50-121 ppm), and calcium (34-164 ppm). RVA analysis revealed clear differences in peak viscosity (PV) and breakdown (BD) among starch samples examined. Higher contents of divalent cations, magnesium, and calcium, were associated with lower values of PV and BD, whereas the phosphorus content did not affect PV and BD. The differences in amylose content, DSC gelatinization properties and color components as well as RS content in raw starch were not large.

Outcomes of Patients Undergoing Endoscopic Hemostasis for the Upper Gastrointestinal Bleeding Were Not Influenced by the Timing of Hospital Emergency Visits: A Situation Prevailing in Japan.

BACKGROUND: The aim of the present study was to determine differences in the prognosis of patients in Japan who underwent emergency endoscopic hemostasis (i) during regular hours versus off hours and (ii) as outpatients versus hospitalized patients. METHODS: The present retrospective study included 443 patients who underwent emergency endoscopic hemostasis for non-variceal upper gastrointestinal bleeding from January 2008 to December 2014. These patients were classified into 2 groups: hospitalized patients and outpatients. The outpatients were further subclassified into those who visited the hospital during regular hours and those who visited during off hours. RESULTS: The outcomes of outpatients who underwent emergency hemostasis during off hours did not differ from patients treated during regular hours. Multivariate analysis revealed that outcomes of hospitalized patients, including mortality, need for blood transfusion and length of hospitalization, were worse than those of outpatients; it also revealed that patient age, malnutrition rate and prevalence of diabetes and neoplasms were higher among hospitalized patients than those in outpatients. CONCLUSIONS: The clinical outcomes of patients who underwent emergency endoscopic hemostasis for upper gastrointestinal bleeding during off hours did not differ from those of patients treated during regular hours. Outcomes were worse among hospitalized patients, mainly because of their bad general condition.

Preparation of iron-fortified potato starch and its properties.

Iron fortification was applied to commercial potato starch by immersion in different concentrations of ferrous sulfate (FeSO4) aqueous solutions. To determine the impact of iron fortification on the properties of potato starch, all of the starches obtained through the process mentioned above were analyzed for their pasting properties, color, gelatinization properties, and resistant starch content. Results indicated that the iron content markedly increased from 16 to 890 ppm when the potato starch was treated with a FeSO4 aqueous solution. During iron fortification, pasting properties markedly changed. Peak viscosity and breakdown decreased while peak viscosity temperature increased with iron fortification. Iron fortification caused a little reduced whiteness (slightly lower L*-value) and enhanced yellowish color (higher b*-value). In contrast, iron fortification had little influence on the gelatinization temperature and enthalpy. Moreover, no significant change in the resistant starch content was observed due to iron fortification.

Expression analysis of polyphenol oxidase isozymes by active staining method and tissue browning of head lettuce (Lactuca sativa L.).

Browning of plant tissue is generally considered attributable to enzymatic oxidation by polyphenol oxidase (PPO). Electrophoresis followed by activity staining has been used as an effective procedure to visually detect and isolate isozymes; however, it has not been applied for examination of various PPO isozymes in lettuce. Our study demonstrated that different lettuce PPO isozymes could be detected at different pH in active staining, and multiple isozymes were detected only under alkaline conditions. As a result, we concluded that activity staining with approximately pH 8 enabled to detect various PPO isozymes in lettuce. By expression analysis of the PPO isozymes after wounding, PPO isozymes that correlated with time-course of tissue browning were detected. The wound-induced PPO may play a key role in enzymatic browning.

Anesthetic effects of isoflurane on the tonotopic map and neuronal population activity in the rat auditory cortex.

Since its discovery nearly four decades ago, sequential microelectrode mapping using hundreds of recording sites has been able to reveal a precise tonotopic organization of the auditory cortex. Despite concerns regarding the effects that anesthesia might have on neuronal responses to tones, anesthesia was essential for these experiments because such dense mapping was elaborate and time-consuming. Here, taking an 'all-at-once' approach, we investigated how isoflurane modifies spatiotemporal activities by using a dense microelectrode array. The array covered the entire auditory cortex in rats, including the core and belt cortices. By comparing neuronal activity in the awake state with activity under isoflurane anesthesia, we made four observations. First, isoflurane anesthesia did not modify the tonotopic topography within the auditory cortex. Second, in terms of general response properties, isoflurane anesthesia decreased the number of active single units and increased their response onset latency. Third, in terms of tuning properties, isoflurane anesthesia shifted the response threshold without changing the shape of the frequency response area and decreased the response quality. Fourth, in terms of population activities, isoflurane anesthesia increased the noise correlations in discharges and phase synchrony in local field potential (LFP) oscillations, suggesting that the anesthesia made neuronal activities redundant at both single-unit and LFP levels. Thus, while isoflurane anesthesia had little effect on the tonotopic topography, its profound effects on neuronal activities decreased the encoding capacity of the auditory cortex.

Discovery and genetic analysis of non-bitter Tartary buckwheat (Fagopyrum tataricum Gaertn.) with trace-rutinosidase activity.

In a screening of about 500 lines of Tartary buckwheat, we identified lines that contained no detectable rutinosidase isozymes using an in-gel detection assay. We confirmed that seeds of these individuals had only a trace level of in-vitro rutinosidase activity. To investigate the heritability of the trace-rutinosidase characteristic, we analyzed the progeny of crosses between rutinosidase trace-lines, 'f3g-162', and the 'Hokkai T8'. The F2 progeny clearly divided into two groups: those with rutinosidase activity under 1.5 nkat/g seed (trace-rutinosidase) and those with activity over 400 nkat/g seed (normal rutinosidase). The segregation pattern of this trait in F2 progeny exhibited 1 : 3 ratio (trace-rutinosidase : normal rutinosidase), suggesting that the trace-rutinosidase trait is conferred by a single recessive gene; rutinosidase-trace A (rutA). In addition, sensory panelists evaluated the bitterness of flour from trace-rutinosidase individuals and did not detect bitterness, whereas flour from normal rutinosidase individuals was found to have strong bitterness. Although at least three bitter compounds have been reported in Tartary buckwheat seeds, our present findings indicate that rutin hydrolysis is the major contributing factor to bitterness. In addition, the trace-rutinosidase line identified here, 'f3g-162', is a promising material for generating a non-bitter Tartary buckwheat variety.

Breeding of 'Manten-Kirari', a non-bitter and trace-rutinosidase variety of Tartary buckwheat (Fagopyrum tataricum Gaertn.).

Here, we developed a new Tartary buckwheat cultivar 'Manten-Kirari', whose flour contains only trace amounts of rutinosidase and lacked bitterness. The trace-rutinosidase breeding line 'f3g-162' (seed parent), which was obtained from a Nepalese genetic resource, was crossed with 'Hokkai T8' (pollen parent), the leading variety in Japan, to improve its agronomic characteristics. The obtained progeny were subjected to performance test. 'Manten-Kirari' had no detectable rutinosidase isozymes in an in-gel detection assay and only 1/266 of the rutinosidase activity of 'Hokkai T8'. Dough prepared from 'Manten-Kirari' flour contained almost no hydrolyzed rutin, even 6 h after the addition of water, whereas the rutin in 'Hokkai T8' dough was completely hydrolyzed within 10 min. In a sensory evaluation of the flour from the two varieties, nearly all panelists detected strong bitterness in 'Hokkai T8', whereas no panelists reported bitterness in 'Manten-Kirari'. This is the first report to describe the breeding of a Tartary buckwheat cultivar with reduced rutin hydrolysis and no bitterness in the prepared flour. Notably, the agronomic characteristics of 'Manten-Kirari' were similar to those of 'Hokkai T8', which is the leading variety in Japan. Based on these characteristics, 'Manten-Kirari' is a promising for preparing non-bitter, rutin-rich foods.