Assessment of the Nutritional Value of Stems and Leaves of Australian Adzuki Bean.

Adzuki bean has recently been proposed as a viable dual-purpose (grain-and-graze) crop for the Northern regions of Australia because of its successful use in semi-arid regions and its nitrogen fixation capacity to improve soil fertility and animal nutrition. However, there are very few studies on the phytochemical composition and nutritional value of the non-seed material. This study investigated the phenolic composition of the parts grown in the vegetative phase (leaves and stems) of nine Australian adzuki bean varieties for the first time. The total phenolic content (TPC) of the stem material (157-406 mg GAE/100 g) was 23-217% higher than that of commercial livestock feed, while the TPC of the leaf material (1158-1420 mg GAE/100 g) was 9-11 times higher. Using tandem liquid chromatography mass spectrometry (LC-MS), the major phenolic compounds identified were rutin, luteolin, salicylic acid, and quercetin-3-glucoside. The leaf and stem materials showed high levels of apparent in vitro dry matter digestibility, with no significant difference in total gas or methane production compared to lucerne hay. The results suggest that adzuki bean vegetative materials could be a high-value livestock fodder and support pursuing further in-depth studies into their nutritional value for livestock.

Increase in steryl glycoside levels and stimulation of lipid raft formation in azuki bean epicotyls under hypergravity conditions.

Sterols are the main components of the plasma membrane and are involved in various plant membrane functions. Azuki bean (Vigna angularis (Wild.) Ohwi et Ohashi) seedlings were cultivated under hypergravity conditions, and changes in the levels and composition of membrane sterols in their epicotyls were analyzed. Under hypergravity conditions at 300 g, the levels of steryl glycosides and acyl steryl glycosides per unit length and per gram fresh weight greatly increased, which accounted for an increase in the total sterol levels. Stigmasterol, ß-sitosterol, and campesterol were the most abundant sterols. Hypergravity decreased the proportion of stigmasterol but increased that of ß-sitosterol. The fatty chains of acyl steryl glycosides mainly consisted of palmitic acid (C16:0), stearic acid (C18:0), linoleic acid (C18:2), and α-linolenic acid (C18:3), and their proportions were not modified under hypergravity conditions. In addition, the density of membrane microdomains, visualized with anti-Flotillin 1 antibody per unit area, increased by hypergravity, suggesting that lipid raft formation was stimulated. These results support the hypothesis that lipid rafts are involved in plant response and resistance to gravity.

Domestication of azuki bean and soybean in Japan: From the insight of archeological and molecular evidence.

Domestication of azuki bean and soybean has enabled them to acquire non-dormant seeds, non-shattering pods, and larger seed size. Seed remains of the Jomon period recently discovered at archeological sites in the Central Highlands of Japan (6,000-4,000 BP) suggest that the use of azuki bean and soybean and their increase in seed size began earlier in Japan than in China and Korea; molecular phylogenetic studies indicate that azuki bean and soybean originated in Japan. Recent identification of domestication genes indicate that the domestication traits of azuki bean and soybean were established by different mechanisms. Analyses of domestication related genes using DNA extracted from the seed remains would reveal further details about their domestication processes.

Modification of Xyloglucan Metabolism during a Decrease in Cell Wall Extensibility in 1-Aminocyclopropane-1-Carboxylic Acid-Treated Azuki Bean Epicotyls.

The exogenous application of ethylene or 1-aminocyclopropane-1-carboxylic acid (ACC), the biosynthetic precursor for ethylene, to plants decreases the capacity of the cell wall to extend, thereby inhibiting stem elongation. In this study, the mechanism by which the extensibility of cell walls decreases in ACC-treated azuki bean epicotyls was studied. ACC decreased the total extensibility of cell walls, and such a decrease was due to the decrease in irreversible extensibility. ACC increased the molecular mass of xyloglucans but decreased the activity of xyloglucan-degrading enzymes. The expression of VaXTHS4, which only exhibits hydrolase activity toward xyloglucans, was downregulated by ACC treatment, whereas that of VaXTH1 or VaXTH2, which exhibits only transglucosylase activity toward xyloglucans, was not affected by ACC treatment. The suppression of xyloglucan-degrading activity by downregulating VaXTHS4 expression may be responsible for the increase in the molecular mass of xyloglucan. Our results suggest that the modification of xyloglucan metabolism is necessary to decrease cell wall extensibility, thereby inhibiting the elongation growth of epicotyls in ACC-treated azuki bean seedlings.

Same Locus for Non-shattering Seed Pod in Two Independently Domesticated Legumes, Vigna angularis and Vigna unguiculata.

Loss of pod shattering is one of the most important domestication-related traits in legume crops. The non-shattering phenotypes have been achieved either by disturbed formation of abscission layer between the valves, or by loss of helical tension in sclerenchyma of endocarp, that split open the pods to disperse the seeds. During domestication, azuki bean (Vigna angularis) and yard-long bean (Vigna unguiculata cv-gr. Sesquipedalis) have reduced or lost the sclerenchyma and thus the shattering behavior of seed pods. Here we performed fine-mapping with backcrossed populations and narrowed the candidate genomic region down to 4 kbp in azuki bean and 13 kbp in yard-long bean. Among the genes located in these regions, we found MYB26 genes encoded truncated proteins in azuki bean, yard-long bean, and even cowpea. As such, our findings indicate that independent domestication on the two legumes has selected the same locus for the same traits. We also argue that MYB26 could be a target gene for improving shattering phenotype in other legumes, such as soybean.

Polyphenol-enriched azuki bean (Vina angularis) extract reduces the oxidative stress and prevents DNA oxidation in the hearts of streptozotocin-induced early diabetic rats.

We examined the changes in the heart of rats at the early stages of streptozotocin (STZ)-induced diabetes, and whether azuki bean extract (ABE) could influence these changes. The experimental diabetic rats received 0 or 40 mg/kg of ABE orally for 4 weeks, whereas the control group rats received distilled water. 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and expression of proteins associated with peroxisomal FA ß-oxidation as well as oxidative stress markers were examined. The levels of peroxisomal ACOX1 and catalase of the diabetic groups were significantly higher than those in the control group. The levels of p62, phosphorylated-p62 (p-p62) and HO-1 in the STZ group were significantly higher than those in the control group, and the levels of p-p62, HO-1, and 8-OHdG were significantly lower by ABE administration. The STZ-induced early diabetes increases the levels of proteins related to peroxisomal FA ß-oxidation and oxidative stress markers in hearts. ABE protects diabetic hearts from oxidative damage.

Azuki bean (Vigna angularis) extract reduces oxidative stress and stimulates autophagy in the kidneys of streptozotocin-induced early diabetic rats.

Diabetic kidney disease is associated with oxidative stress, inflammation, and autophagy. The aim of this study was to investigate the effect of azuki bean (Vigna angularis) extract (ABE) on oxidative stress and autophagy in the kidneys of diabetic rats. Streptozotocin (STZ)-induced diabetic rats received 0, 10, or 40 mg/kg of ABE orally for 4 weeks, whereas vehicle-injected control rats received distilled water. Level of plasma glutathione and expression of heme oxygenase-1 (HO-1), p47phox (NADPH oxidase subunit), and markers associated with autophagy were examined. The glutathione level in the 40 mg/kg ABE-treated diabetic group (ABE-40 group) was higher than that of the untreated diabetic group (ABE-0 group). The HO-1 and p47phox protein expression levels of the ABE-40 group were lower (47% and 33%, respectively) than those of the ABE-0 group. The level of light chain 3B II (LC3B-II) was higher in the ABE-40 group than in the ABE-0 group. Protein levels of p62/sequestosome 1 (p62) in the ABE-40 group were lower than those in the ABE-0 group. Our results suggest that ABE may attenuate STZ-induced diabetic kidney injury by suppressing oxidative stress and (or) by upregulating autophagy.

Genotypic difference in (137)Cs accumulation and transfer from the contaminated field in Fukushima to azuki bean (Vigna angularis).

The screening of mini-core collection of azuki bean accessions (Vigna angularis (Willd.) Ohwi & Ohashi) for comparative uptake of (137)Cs in their edible portions was done in field trials on land contaminated by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Ninety seven azuki bean accessions including their wild relatives from a Japanese gene bank, were grown in a field in the Fukushima prefecture, which is located approximately 51 km north of FDNPP. The contamination level of the soil was 3665 ± 480 Bq kg(-1) dry weight ((137)Cs, average ± SD). The soil type comprised clay loam, where the sand: silt: clay proportion was 42:21:37. There was a significant varietal difference in the biomass production, radiocaesium accumulation and transfer factor (TF) of radiocaesium from the soil to edible portion. Under identical agricultural practice, the extent of (137)Cs accumulation by seeds differed between the accessions by as much as 10-fold. Inter-varietal variation was expressed at the ratio of the maximum to minimum observed (137)Cs transfer factor for seeds ranged from 0.092 to 0.009. The total biomass, time to flowering and maturity, and seed yield had negative relationship to (137)Cs activity concentration in seeds. The results suggest that certain variety/varieties of azuki bean which accumulated less (137)Cs in edible portion with preferable agronomic traits are suitable to reduce the (137)Cs accumulation in food chain on contaminated land.

Azuki bean (Vigna angularis) extract stimulates the phosphorylation of AMP-activated protein kinase in HepG2 cells and diabetic rat liver.

BACKGROUND: The activation of AMP-activated protein kinase (AMPK) has a beneficial effect on hyperglycaemia. The aim of this study was to examine whether an azuki bean (Vigna angularis) extract (ABE) stimulates the AMPK or insulin signalling pathways in a liver cell line in response to hyperglycaemia, as well as in a diabetic rat liver. RESULTS: HepG2 cells were incubated with 5 or 20 mmol L(-1) glucose and then treated with ABE. Streptozotocin-induced diabetic rats received 0, 10, or 40 mg kg(-1) ABE orally. Blood chemistry and phosphorylation of AMPK and Akt (a serine/threonine kinase) in the livers were examined. There was a significant increase in the levels of AMPK and Akt phosphorylation in ABE-treated HepG2 cells. AMPK phosphorylation increased significantly in glucose-stimulated HepG2 cells that were treated with ABE. In the 40 mg kg(-1) ABE-treated diabetic rats, the glucose levels were lower than in the control. Phosphorylation of AMPK in ABE-untreated diabetic rat livers decreased significantly. Conversely, ABE treatment increased the phosphorylation of AMPK and Akt in the diabetic rat liver. CONCLUSION: ABE treatment upregulated AMPK phosphorylation in HepG2 cells, and upregulated AMPK and Akt phosphorylation in the diabetic rat liver. These data suggest that ABE can potentially improve glucose intolerance.

De novo assembly of the complete organelle genome sequences of azuki bean (Vigna angularis) using next-generation sequencers.

Since chloroplasts and mitochondria are maternally inherited and have unique features in evolution, DNA sequences of those organelle genomes have been broadly used in phylogenetic studies. Thanks to recent progress in next-generation sequencer (NGS) technology, whole-genome sequencing can be easily performed. Here, using NGS data generated by Roche GS Titanium and Illumina Hiseq 2000, we performed a hybrid assembly of organelle genome sequences of Vigna angularis (azuki bean). Both the mitochondrial genome (mtDNA) and the chloroplast genome (cpDNA) of V. angularis have very similar size and gene content to those of V. radiata (mungbean). However, in structure, mtDNA sequences have undergone many recombination events after divergence from the common ancestor of V. angularis and V. radiata, whereas cpDNAs are almost identical between the two. The stability of cpDNAs and the variability of mtDNAs was further confirmed by comparative analysis of Vigna organelles with model plants Lotus japonicus and Arabidopsis thaliana.

Azuki bean (Vigna angularis) extract inhibits the development of experimentally induced atopic dermatitis-like skin lesions in NC/Nga mice.

The present study investigated the effects of azuki bean (Vigna angularis) extract (VAE) on the progress of atopic dermatitis (AD)-like skin lesions in NC/Nga mice induced by 1-chloro-2,4-dinitrobenzene. The efficacy of VAE in NC/Nga mice was determined by measuring gross and histological skin lesions, serum IgE levels, eosinophil ratio in peripheral leucocytes, and mRNA expression levels of interleukin (IL)-4, tumour necrosis factor (TNF)-α and interferon (IFN)-γ in splenocytes. Continuous ingestion of VAE inhibited the development of the AD-like skin lesions in a dose-dependent manner. In the VAE-treated mice, the numbers of mast cells in the skin, eosinophil ratio in peripheral leucocytes, relative mRNA expression of inflammatory cytokines in the spleen, and serum IgE levels were significantly reduced. Results suggest that VAE can inhibit the development of AD-like skin lesions in NC/Nga mice by regulating immune mediators and cells, and may be an effective alternative therapy for AD.

Developmental schedules and persistence of experimental host-parasitoid systems at two different temperatures.

In experimental systems of a bruchid host, Callosobruchus chinensis, and a braconid parasitoid, Heterospilus prosopidis, the effects of changes in developmental schedules were examined in relation to the persistence of the system, or the time to extinction of a component species. We modified the developmental schedules by changing the temperature from 30°C to 32°C. To compare persistence, a long-term system with overlapping generations was set up and the bruchid host resource, azuki beans (Vigna angularis), were renewed every 10 days. The long-term systems showed greater persistence at 30°C than at 32°C. Parasitoid extinction was often observed. We examined differences in life-history characteristics of the component species between the two temperatures by short-term, single-generation experiments. Fecundity and egg hatchability of the host were reduced and the developmental period of the parasitoid was shortened at 32°C. The age at which the host became vulnerable to parasitoid attacks was earlier at 32°C than at 30°C. We constructed a daily based, age-structured model to analyse which life-history change(s) affected the persistence of the long-term systems. The density-dependent population growth of the host was described by a logistic equation and the attack rate of the parasitoid by a type II functional response with mutual interference. The simulation results showed greater persistence at 30°C than at 32°C. Sensitivity analysis showed that there are threshold boundaries in the length of the vulnerable period of the host beyond which system persistence drastically changes. Further, persistence at another temperature, 28°C, was predicted using a model based on short-term data on the host.