Reactions of (+)-catechin with salivary nitrite and thiocyanate under conditions simulating the gastric lumen: Production of dinitrosocatechin and its thiocyanate conjugate

Abstract

Catechins are ingested as food components and supplements. It is known that catechins are transformed to dinitrosocatechins by nitrite under acidic conditions, suggesting the possibility of their formation in the stomach because saliva contains nitrite. This paper deals with nitrite-induced transformation of (+)-catechin in methanol extracts of adzuki bean into 6,8-dinitrosocatechin in acidified saliva (pH ≈ 1.9). As the mechanism of its formation, addition of nitric oxide (NO) to (+)-catechin semiquinone radical, both of which were produced in nitrous acid/(+)-catechin systems, was proposed. The dinitrosocatechin was oxidized to the quinone by nitrous acid, and the quinone reacted with a salivary component thiocyanate producing 6′-thiocyanato-6,8-dinitrosocatechin. Since quinones are toxic, we propose a function of thiocyanate as a scavenger of the o-quinone formed from dinitrosocatechins in the stomach.     

Syntheses and Biological Activities of (2S,2′ S)- and (2S,2′R)-Dimethyl 3-Phenyl-2,2′-oxydipropionate,Ether Analogues of a Plant-growth Regulator Isolated from Botrytis squamosa

Ether analogues of a plant growth regulator isolated from Botrytis squamosa, (2S,2′S)- and (2S,3′S)-dimethyl 3-phenyl-2,2′-oxydipro-pionate (1), were prepared by the Williamson synthesis, and the two diastereomers were separated. The absolute configurations of both diastereomers were determined by chemical transformation. The promoting effect of both synthesize analogues on lettuce seedling growth was similar to that of the natural plant growth regulator.     

Genome dissection of traits related to domestication in azuki bean (Vigna angularis) and comparison with other warm-season legumes

BACKGROUND: The objective of this study was to dissect into quantitative trait loci (QTLs) the large morphological and physiological differences between cultivated azuki bean (Vigna angularis) and a wild relative and to infer the commonalities of the QTLs for domestication-related traits across the Asian Vigna and with other warm-season legumes. METHODS: Two linkage maps, for the BC(1)F(1) and F(2) populations, respectively, from the same cross between azuki bean and V. nepalensis were developed. Using these linkage maps QTLs for 33 domestication-related traits were analysed and mapped. The location of mapped QTLs was compared with locations of similar QTLs in other warm-season legumes. KEY RESULTS: QTLs were detected for seed-, pod-, stem- and leaf-related traits. Most traits were controlled by between two and nine QTLs but several traits, such as pod dehiscence, were controlled by single genes. QTLs for domestication-related traits were restricted to particular regions of the azuki bean genome, especially linkage groups 1, 2, 4, 7 and 9. Linkage groups 1 and 2 had QTLs for a suite of traits including pod size, germination, seed size and lower stem length. QTLs on linkage groups 7 and 9 were associated with upper stem length, maximum leaf size and pod and seed size. Pleiotropy or close linkage of genes for domestication-related traits is suggested in these regions. While some QTLs are common to azuki bean and other warm-season legumes, many are recorded for the first time in azuki bean. CONCLUSIONS: QTLs for a large number of domestication-related traits have been mapped for the first time in azuki bean. QTLs with unexpected effect and new QTLs for traits such as seed size have been found. The results provide a foundation that will be useful for improvement of azuki bean and related legumes.     

Effects of temperature on the cell wall and osmotic properties in dark-grown rice and azuki bean seedlings

The mechanism inducing the difference in growth rate under various temperature (10–50 °C) conditions was analyzed using rice and azuki bean seedlings. The growth rate of rice coleoptiles and azuki bean epicotyls increased as temperature increased up to 40 and 30 °C, respectively, and the elongation was retarded at a higher temperature. The cell wall extensibility of rice coleoptiles and azuki bean epicotyls also showed the highest value at 40 and 30 °C, respectively, and became smaller as the temperature rose or dropped from the optimum. The opposite tendency was observed in the minimum stress-relaxation time of the cell wall. On the other hand, the cellular osmotic concentration of rice coleoptiles and azuki bean epicotyls was lower at the temperature optimum for growth at 40 and 30 °C, respectively. When rice and azuki bean seedlings grown at 10, 20, 40, or 50 °C were transferred to the initial temperature (30 °C), the growth rate of coleoptiles and epicotyls was mostly elevated, concomitant with an increase in the cell wall extensibility. The growth rate was correlated with the cell wall mechanical parameters in both materials. These results suggest that the environmental temperature modulates the growth rate of plant shoots by affecting mainly the mechanical properties of the cell wall. Electronic Publication     

Effects of fusicoccin and indole-3-acetic acid on the levels of ascorbic acid and dehydroascorbic acid in the apoplast during elongation of epicotyl segments of Vigna angularis

The levels of ascorbic acid (AA) and dehydroascorbic acid (DHA) in the apoplast of epicotyl segments from Vigna angularis L. cv. Erimoshouzu decreased to nearly zero and about 35%, respectively, of their initial levels, 3 h after the preparation of the epicotyl segments. The decreased level was kept nearly constant between 3 and 7 h. Fusicoccin (FC) and indole-3-acetic acid (IAA) slightly amplified the initial decrease in the level of AA, but suppressed the initial decrease in the level of DHA while enhancing elongation growth. During incubation for 3 and 7 h, FC then increased the levels of both AA and DHA, whereas IAA did so only with DHA. By the addition of FC 4 h after the start of incubation, the levels of both AA and DHA were also increased. The uncoupler carbonylcyanide m -chlorophenyl hydrazone increased the levels of both AA and DHA in the apoplast inhibiting elongation growth. These results suggest that the electrochemical proton gradient across the plasma membrane is one of the factors that control the apoplastic levels of AA and DHA.     

Gibberellins in Immature Seeds of Canavalia

Two novel gibberellins, GA₂₁ (I) and GA₂₂ (II), were isolated from immature seeds of sword bean, Canavalia gladiata DC. The isolation procedure of these substances as well as their growth-promoting effects on dwarf maize mutants d₁ and d₅, rice, cucumber and dwarf peas (Progress No. 9) are described.

The structures of two new gibberellins, GA₂₁ and GA₂₂, isolated from immature seeds of sword bean, were determined as 4a_α, 7_α-dihydroxy-8-methylenegibbane-1, 1, 10β-tricarboxylic acid 1→4a lactone (II) and 4a_α, 7_α-dihydroxy-l β-hydroxymethyl-8-methylenegibb-2-ene-1_α, 10β-dicaboxylic acid 1→4a lactone (IV), respectively, on the basis of chemical and physicochemical studies.     

Comparative molecular mapping in Ceratotropis species using an interspecific cross between azuki bean (Vigna angularis) and rice bean (V. umbellata)

A genetic linkage map was developed with 86 F₂ plants derived from an interspecific cross between azuki bean (Vigna angularis, 2n=2x=22) and rice bean (V. umbellata, 2n=2x=22). In total, 14 linkage groups, each containing more than 4 markers, were constructed with one phenotypic, 114 RFLP and 74 RAPD markers. The total map size was 1702 cM, and the average distance between markers was 9.7 cM. The loci showing significant deviation from the expected ratio clustered in several linkage groups. Most of the skewed loci were due to the predominance of rice bean alleles. The azuki-rice bean linkage map was compared with other available maps of Vigna species in subgenus Ceratotropis. Based on the lineage of the common mapped markers, 7 and 16 conserved linkage blocks were found in the interspecific map of azuki bean ×V. nakashimae and mungbean map, respectively. Although the present map is not fully saturated, it may facilitate gene tagging, QTL mapping and further useful gene transfer for azuki bean breeding. Received: 20 March 1999 / Accepted: 29 April 1999     

Hot-Water Extracts from Adzuki Beans (Vigna angularis) Stimulate Not Only Melanogenesis in Cultured Mouse B16 Melanoma Cells but Also Pigmentation of Hair Color in C3H Mice

A hot-water extract of adzuki was obtained by boiling beans of adzuki (Vigna angularis). This hot-water extract was fractionated using HP-20 column chromatography. Its distilled water fraction (WEx) was found to stimulate tyrosinase activity in cultured mouse B16 melanoma cells and hair color pigmentation in C3H mice. At concentrations of 1–3 mg/ml, WEx stimulated melanogenesis without inhibiting cell growth. During this effect, WEx activated tyrosinase-inducing activity in the cells, but did not activate tyrosinase, which exists at an intracellular level. In this study, WEx increased cyclic adenosine-3′,5′-monophospate (cAMP) content in the cells and protein kinase A (PKA) activity, and stimulated translocation of cytosolic protein kinase C (PKC) to the membrane-bound PKC. These results suggest that the addition of WEx activates the adenylcyclase and protein kinase pathways and, as a result, stimulates melanogenesis. WEx was found to have pigmentation activity on hair color in C3H mice. It might be useful in anti-graying, protecting human skin from irradiation.     

小豆VaDREB1A基因克隆及其应答锈菌侵染的表达分析

为明确小豆VaDREB1A在抗锈菌侵染过程中的作用,本研究分别从小豆基因组DNA及cDNA中克隆了该基因,测序结果表明VaDREB1A无内含子,全长660 bp编码219个氨基酸,氨基酸序列包含1个AP2结构域,序列特征及系统发育分析表明VaDREB1A属于DREB/CBF亚家族A1亚类。启动子顺式元件分析发现,VaDREB1A启动子包含乙烯、水杨酸及生物和非生物胁迫等响应元件。对该基因响应豇豆单胞锈菌(Uromyces vignae)侵染的表达分析发现,与不接种对照相比,VaDREB1A在抗病品种中于接种后24 h和120 h显著下调,而在感病品种中于接种后120 h和192 h显著上调。在1-氨基环丙烷-1-羧酸(ACC)诱导小豆抗锈病过程中,VaDREB1A的表达与其在抗病品种中的表达相似,分别于ACC处理并接种后24 h和192 h显著下调。上述结果说明VaDREB1A可能参与小豆对锈病的抗性。     

Gibberellins in Immature Seeds of Pharbitis nil

Two new gibberellins, gibberellins A₂₆ and A₂₇ were isolated from immature seeds of Japanese morning-glory (Pharbitis nil) and their structures were elucidated as I and IX.     

Inhibition of auxin-induced elongation and xyloglucan breakdown in azuki bean epicotyl segments by fucose-binding lectins

Auxin-induced elongation of epicotyl segments of azuki bean ( Vigna angularis Ohwi and Ohashi cv. Takara) was suppressed by fucose-binding lectins from Tetragonolobus purpureus Moench and Ulex europaeus L. These lectins also inhibited auxin-induced cell wall loosening (decrease in the minimum stress-relaxation time of the cell walls) of segments. Auxin caused a decrease in molecular mass of xyloglucans extracted with 24% KOH from the cell walls. The lectins inhibited auxin-induced changes in molecular mass of the xyloglucans. The autolytic release of xylose-containing products from the pectinase-treated cell walls was also suppressed by the lectins. Fucose-binding lectins pretreated with fucose exhibited little or no inhibitory effect on auxin-induced elongation, cell wall loosning, or breakdown of xyloglucans. These results support the view that the breakdown of xyloglucans is involved in the cell wall loosening responsible for auxin-induced elongation in dicotyledons.     

The Location of Cytokinins and Gibberellins in Wheat Seeds

Wheat seeds (Triticum aestivum L. cvs. Yorkstar and Sirius) were cut transversely into embryoless and embryo-containing (embryonated) halves and the content of endogenous cytokinins and gibberellins in both halves determined before and after the seeds imbibed water for 12–15 h at 22°C in the light. Dry seeds contained little ethyl acetate-extractable gibberellin activity as measured by bioassay but n-butanol-soluble cytokinins were detected mainly in the embryoless halves. Dry, embryonated half-seeds contained water-soluble gibberellins which could be extracted into acidic ethyl acetate after treatment of the aqueous extract with either alkaline phosphatase, β-glucosidase or a crude pectolytic enzyme preparation. When half-seeds were allowed to imbibe water for 12 h and then extracted, cytokinin activity was largely lost from the embryoless halves and completely from the embryonated halves and water-soluble gibberellins were also lost from the embryonated halves. However, ethyl acetate-soluble gibberellins were present in the latter suggesting that “bound’ gibberellins were released during imbibition. The hormones present in normal and naturally embryoless dry grains of cv. Yorkstar were also determined. Both gibberellin and cytokinin activity was higher in normal grains suggesting that the presence of an embryo is essential for synthesis or accumulation of these hormones in the grain during development.     

Cell division and cell enlargement in fruit of Lagenaria leucantha as influenced by pollination and plant growth substances

The effects of NAA (naphthaleneacetic acid), GA₃ (gibberellic acid), CPPU (N-(2-chloro-4-pyridyl)-N'-phenylurea) and pollination on fruit set, cell division and enlargement were studied in Lagenaria leucantha, an important vegetable. NAA and GA₃ were ineffective in inducing parthenocarpy, whereas CPPU induced parthenocarpic fruit significantly larger than fruit that resulted from pollination. Cell division, which occurred during the first 4 days after pollination was not reactivated by NAA or GA₃, but was effectively reactivated by CPPU. The cell number of the total cross-section of CPPU-treated fruit was 117.4% of that of pollinated fruit and 154.4% of that of unpollinated at 12 DAA (days after anthesis) respectively. The CPPU-induced parthenocarpic fruit had the largest cell cross-sectional area followed, successively, by pollinated fruit, NAA-treated fruit, GA₃-treated fruit and unpollinated fruit. These results indicate that CPPU induced parthenocarpic fruit growth by directly reactivating cell division and expansion.     

<Emphasis Type="Italic">Bradyrhizobium</Emphasis> spp. and <Emphasis Type="Italic">Sinorhizobium fredii</Emphasis> are predominant in root nodules of <Emphasis Type="Italic">Vigna angularis</Emphasis>, a native legume crop in the subtropical region of China

Adzuki bean (Vigna angularis) is an important legume crop native to China, but its rhizobia have not been well characterized. In the present study, a total of 60 rhizobial strains isolated from eight provinces of China were analyzed with amplified 16S rRNA gene RFLP, IGS-RFLP, and sequencing analyses of 16S rRNA, atpD, recA, and nodC genes. These strains were identified as genomic species within Rhizobium, Sinorhizobium, Mesorhizobium, Bradyrhizobium, and Ochrobactrum. The most abundant groups were Bradyrhizobium species and Sinorhizobium fredii. Diverse nodC genes were found in these strains, which were mainly co-evolved with the housekeeping genes, but a possible lateral transfer of nodC from Sinorhizobium to Rhizobium was found. Analyses of the genomic and symbiotic gene backgrounds showed that adzuki bean shared the same rhizobial gene pool with soybean (legume native to China) and the exotic Vigna species. All of these data demonstrated that nodule formation is the interaction of rhizobia, host plants, and environment characters. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users.     

Structures of Gibberellins A33 and A34 from Immature Seeds of Calonyction aculeatum

Several kinds of modified chymotrypsin were prepared with water-soluble acylating reagents, and their characteristics after hydrolyzing with unmodified chymotrypsin in aqueous-N,N’ -dimethylformamide (DMF) media were compared. It was found that chymotrypsin (Csin), of which a 20% amino group was modified with a benzyloxycarbonyl group (Z(20)Csin), had more favorable characteristics than unmodified chymotrypsin with regard to hydrolytic activity in an aqueous DMF media. We also investigated the Z(20)Csin-catalyzed peptide synthesis in two different solution systems. In the one-layer system containing water and DMF, Z(20)Csin catalyzed the peptide bond formation in a higher yield than that by unmodifide chymotrypsin and enabled a synthetic reaction in even an 80% (v/v) DMF media, in which the hydrolytic reaction could not be carried out. Z(20)Csin catalyzed the condensation between some N-acyl amino acids or peptide derivatives and amino acids in 90% ethylacetate, 90% hexane or 50% benzene. This latter method employs a two-layer system, and the modified enzyme may be able to reduce the number of synthetic steps when preparing acyl peptides.     

Role of xyloglucan breakdown in epidermal cell walls for auxininduced elongation of azuki bean epicotyl segments

Auxin-induced elongation of epicotyl segments of azuki bean ( Vigna angularis Ohwi et Ohashi cv. Takara) was suppressed by a fucose-binding lectin from Tetragonolobus purpureas Moench and by polyclonal antibodies raised against xyloglucan heptasaccharide (Xyl₃Glc₄) when the cuticle present in the outer surface of epicotyls was abraded. In contrast, elongation of non-abraded segments was not influenced by the lectin or the antibodies. Epicotyl segments, from which the epidermal and the outer cortical cells had been removed, elongated rapidly for 2 h and than only slowly. Auxin slightly stimulated elongation of the inner tissue segments in the phase of slow growth. Neither in the presence nor in the absence of auxin did the lectin or the antibodies affect elongation of the inner tissue segments. The split portions of outer surface-abraded epicotyl segments incubated in buffer extended outward, and auxininhibited this outward bending. The lectin and the antibodies reversed the effect of auxin on bending. The fucose-binding lectin pretreated with fucose or the immunoglobulin fraction obtained from preimmune serum exhibited little or no inhibitory effect on auxin-induced elongation of abraded or split segments. These results support the view that a breakdown of xyloglucans in the epidermal cell walls plays an essential role in auxin-induced elongation in dicotyledons.     

CPPU对瓠瓜单性结实的诱导作用及对细胞分裂和内源激素水平的影响

NAA和GA3处理未经授粉的瓠瓜子房不能显著促进其细胞分裂和膨大而产生单性结实果,而CP-PU处理未经授粉的瓠瓜子房则使其细胞数目和中果皮单个细胞横切面积以及单果重都显著高于未授粉和人工授粉果.经CPPU诱导座果而产生的单性结实果中IAA、ABA和t-zeatin的浓度均不同程度地低于人工授粉和不授粉果实.     

Isolation and Characterization of Gibberellins in Mature Seeds of Phaseolus vulgaris

The change of endogenous gibberellin in the germinated seeds of Phaseolus vuigaris cv. Kentucky Wonder was investigated. Based on this result, endogenous gibberellins in the mature seeds were extensively investigated to result in the isolation of GA₁, GA₈, GA₈ glucoside, AB-II (unknown gibberellin-like substance) and glucosyl esters of GA₁, GA₄, GA₃₇ and GA₃₈.     

Conjugates of 3-phenyllactic acid and tryptophan enhance root-promoting activity without adverse effects in Vigna angularis

3-Phenyllactic acid (PLA) is a common secondary product of Lactobacillus sp. and promotes adventitious-root formation in Azuki beans (Vigna angularis). Root promotion activity of PLA is synergistically enhanced by tryptophan (Trp). In this study, stereoisomers of PLA and Trp amide conjugates and their alkyl esters were synthesized to investigate the structure–activity relationships on root-promotion activity. The rooting activity of D-PLA-L-Trp conjugate shows more than 40 times higher than that of the mixture of D-PLA and L-Trp. Modification of PLA-Trp with ethyl ester showed the highest activity at 3,400 times of a mixture of D-PLA and L-Trp. However, L-or D-PLA-D-Trp conjugate and the isopropyl ester of PLA-Trp conjugates, both lost the root promotion activity and implicated that a requirement for steric structure for PLA related root promotion mechanism. Unlike auxin substances, which are commonly used as rooting agents that displayed high activity in low concentrations, PLA-Trp ethyl ester exhibited far less phytotoxicity at high concentration of 1 mM, despite its high rooting activity. Innovation of PLA-Trp ethyl ester may be expected for agricultural aspects with low environmental impact.     

In vitro molecular weight increase in xyloglucans by an apoplastic enzyme preparation from epicotyls of Vigna angularis

In order to gain insight into the mechanism of cell extension growth, enzymic processes involved in structural modification of cell wall xyloglucans were investigated, using an apoplastic enzyme preparation from epicotyls of dark grown Vigna angularis Ohwi et Ohashi cv. Takara and purified xyloglucans derived from cell walls of Vigna. The reaction of Vigna xyloglucan (mass average molecular weight=420 kDa) with the apoplastic enzyme preparation gave three fractions: (1) a waterinsoluble high molecular weight (820 kDa) xyloglucan fraction (WI), (2) a watersoluble low molecular weight (149 kDa) xyloglucan fraction (WS), and (3) an 80% ethanol-soluble monosaccharide fraction (ES). WI and WS were chiefly composed of t -galactosyl-, t -xylosyl-, 2-xylosyl-, 4-glucosyl- and 4,6-glucosyl residues, whereas ES was composed of fucose, galactose, glucose and xylose monomers. The data indicate that WI is generated by the linking of xyloglucan molecules by some alkali stable linkages, probably of glycosidic nature. The optimal pH for the WI-producing activity of the apoplastic enzyme preparation was 5.4. Higher WI-producing activity was detected in the upper juvenile than in the lower non-elongating regions of the epicotyl. Our data suggest the possible involvement of a transglycosylation reaction in the structural changes of the xyloglucans that are responsible for cell extension growth of the Vigna angularis epicotyl. The data are also consistent with the idea that the enzymic processes are regulated by hydrogen ions in the apoplastic space.