Glucosinolates,flea beetle resistance,and leaf pubescence as taxonomic characters in the genus Barbarea (Brassicaceae)

Glucosinolate content of leaves and roots, diversity in leaf pubescence, and resistance to two near-isogenic lines of the flea beetle Phyllotreta nemorum with or without an R-gene, were determined for 27 accessions of 7 Barbarea taxa, i.e. B. stricta, B. orthoceras, B. intermedia, B. verna, B. vulgaris var. vulgaris, the G-type of B. vulgaris var. arcuata and the P-type of B. vulgaris var. arcuata. Four variable glucosinolate biosynthetic characters were deduced. For (formally) homophenylalanine-derived glucosinolates: (1). Presence or absence of 2-hydroxylation, and if present, R- or S-configuration of 2-hydroxylation; (2). presence or absence of p-hydroxylation; and for tryptophan-derived glucosinolates: (3). presence or absence of N-methoxyglucobrassicin; and (4). presence or absence of 1,4-dimethoxyglucobrassicin. Three phenotypes of leaf-pubescence were observed; (1). glabrous to glabrate leaves; (2). glabrous to glabrate leaves with hairs along the edge; (3). pubescent leaves. The hairs were characterized as simple by scanning electron microscopy. Full resistance to a flea beetle line (ST) was found in B. vulgaris var. vulgaris and in the G-type of var. arcuata; partial resistance was found in B. verna and B. intermedia, while the remaining taxa were fully susceptible to the ST line. All investigated Barbarea taxa were susceptible to larvae from another line containing an R-gene, indicating a similar flea beetle resistance mechanism in the three resistant species. Most Barbarea taxa could be characterized by a particular combination of the investigated characters. The most aberrant was the P-type of B. vulgaris var. arcuata, and the taxonomic status of this type should be reconsidered.     

Glucosinolates in Sesamoides canescens and S. pygmaea: Identification of 2-(α-l-arabinopyranosyloxy)-2-phenylethylglucosinolate

A new natural product, 2-(α-l-arabinopyranosyloxy)-2-phenylethylglucosinolate, has been isolated from Sesamoides canescens. This glucosinolate together with 2-hydroxy-2-phenylethylglucosinolate and 2-phenetliylglucosinolate in a 1:1:1 ratio constitutes about 90 % of the total glucosinolate pool in green parts of the plant. Phenethylglucosinolate constitutes about 70 % of the total glucosinolate pool in green parts of S. pygmaea together with minor amounts of the two other glucosinolates. In addition, both plants contain at least seven other glucosinolates. The structure of the new natural product has been confirmed by transformations into d-glucose, l-arabinose, N-(2-(α-l-arabinopyranosyloxy)-2-phenylethyl)thiourea, 3-(α-l-arabinopyranosyloxy)-3-phenylpropionitrile and 3-hydroxy-3-phenylpropionic acid, respectively. The significance of this investigation is briefly discussed in relation to the methods used in glucosinolate analysis, chemotaxonomy and possible catabolic transformation of glucosinolates into amines.     

Isolation of glucosinolates and the identification of o-(α-l-rhamnopyranosyloxy)benzylglucosinolate from Reseda odorata

A method has been developed for the quantitative isolation of glucosinolates by ion-exchange chromatography and high voltage electrophoresis avoiding strongly alkaline and acidic conditions. The compounds were identified by ¹H and ¹³C NMR spectroscopy and through the products arising from enzymatic, acid and alkaline hydrolysis. The method is well suited for the isolation and identification of glucosinolates containing aglucone parts which produce non-volatile compounds on enzymatic hydrolysis. The method has been used in the isolation and identification of 2-hydroxy-2-methylpropylglucosinolate from Reseda alba, 2-hydroxy-2-phenylethylglucosinolate from R. luteola and a new glucosinolate, o-(α-l-rhamnopyranosyloxy)benzylglucosinolate, occurring in R. odorata. The glucosinolate content in different parts of this plant has been determined and the metabolism of glucosinolates is briefly discussed.     

Studies of the Biochemical Background to Differences in Glucosinolate Content in Brassica napus L. II. Administration of Some Sulphur-35 and Carbon-14 Compounds and Localization of Metabolic Blocks

The aim of the investigation was to study the differences in the metabolism of substances that are utilized in the synthesis of glucosinolates between the Brassica napus cv. Bronowski, which is very low in glucosinolate content, and a cultivar (cv. Regina II) that contains approximately average amounts of these compounds. By experiments in which the plants were grown in nutrient solutions supplied with sulphate-³⁵S, it was shown that the rate of sulphate uptake was similar in the two cultivars. No accumulation of intermediate metabolites could be demonstrated by autoradiography in Bronowski. Sulphate-³⁵S, methionine-³⁵S, methionine-2-¹⁴C, 2-amino-6-(methylthio)caproic acid-2-¹⁴C, and S-(β-d -glucopyranosyl)-4-pentenethiohydroximic acid (desulpho-3-butenylglucosinolate) (glucose-U-¹⁴C or ³⁵S) were fed to shoots of the two cultivars. After incubation, the plant material was extracted with methanol. The extracts were separated into various fractions, and in some experiments glucosinolates or derivatives of their degradation products were isolated. When measuring the radioactivity of the various fractions or isolated products, the incorporation of radioactivity into glucosinolates was found to be poor in Bronowski from sulphate, methionine, and 2-amino-6-(methylthio)caproic acid. Desulpho-3-butenyl-glucosinolate was an efficient precursor of 3-butenylglucosinolate in Bronowski, but a poor precursor of 2-hydroxy-3-bute-nylglucosinolate, which suggests a metabolic block at the hydroxylation step in this cultivar. In Regina II desulpho-3-butenylglucosinolate was a good precursor of both 3-butenylglucosinolate and of 2-hydroxy-3-butenylglucosinolate, which demonstrates that these glucosinolates may be synthesized without prior formation of the corresponding co-methylthioalkyl glucosinolates and that the hydroxylation can take place after the formation of desulpho-3-butenylglucosinolate. The results indicate that the low glucosinolate content of Bronowski is caused by block(s) in the separate pathway leading to the biosynthesis of glucosinolates.     

Changes in glucosinolates during crop development in single- and double-low genotypes of winter oilseed rape (Brassica napus): II. Profiles and tissue-water concentrations in vegetative tissues and developing pods

The concentrations of glucosinolates in the tissue water of leaves, stems, floral buds and developing pods were measured at defined stages of development in four oilseed rape cultivars known to have different seed glucosinolate concentrations (Bienvenu, Ariana, Cobra and Capricorn). Five alkenyl, two aromatic and three indolyl compounds were identified in the vegetative and reproductive organs. Substantial differences developed in the profiles of compounds present during vegetative growth. The 2-hydroxy-3-butenyl glucosinolate was primarily associated with developing and mature seeds and germinated seedlings. The 4-pentyl glucosinolate occurred mainly during the later stages of vegetative growth in spring, when leaves contained higher concentrations than stems, and during the early stages of flowering. The 2-phenylethyl and 3-indolymethyl glucosinolates were present earlier in vegetative growth when similar concentrations were present in leaves and stems. Differences between cultivars in the tissue-water concentrations of individual glucosinolates were small during vegetative growth. The leaves of Cobra and Capricorn had smaller concentrations of the 3-pentyl glucosinolate than Bienvenu and Ariana especially early in spring, and the stems of Capricorn had smaller concentration of the 3-pentyl and 2-phenylethyl glucosinolates. Greater differences between cultivars developed during pod growth and involved large increases in the concentrations of the 2-hydroxy-3-butenyl and 3-butenyl glucosinolates, especially in Bienvenu and Ariana. The implications of these changes in the types and concentrations of glucosinolates in the different organs for the incidence of pests and diseases are discussed.     

Seasonal variation in glucosinolate content in Brassica oleracea crops grown in northwestern Spain

Brassica oleracea L. crops including kales, cabbages, and Tronchuda cabbages are widely grown in northwestern Spain and Portugal but little information is available on leaf glucosinolate content of these crops. The objectives were to determine the diversity for the total glucosinolate content and profile on leaves in a collection of 153 kales, 26 cabbages, and three Tronchuda cabbages varieties grown at two growing seasons and to determine the seasonal variation of glucosinolates in cabbages and Tronchuda cabbage varieties. Sinigrin, glucoiberin, and glucobrassicin were the major glucosinolates found in kales. Glucoiberin was the most common glucosinolate in Tronchuda cabbages in both planting seasons and in cabbages sown in fall season whereas glucobrassicin and glucoiberin were the most common glucosinolates in cabbages in spring season. In kales the total glucosinolate content ranged from 11.0 to 53 micromol g(-1) dw, with a mean value of 26.3 micromol g(-1) dw. Four kale varieties (MBG-BRS0468, MBG-BRS0476, MBG-BRS0060 and MBG-BRS0223) showed the highest total sinigrin or glucobrassicin contents. So, they could be good candidates for future breeding programs. In cabbages, the total glucosinolate content ranged from 10.9 to 27 g(-1) dw. Total glucosinolate concentration during spring sowing (22 micro mg(-1) dw) was higher than those in fall sowing (13 micro mg(-1) dw). Regarding both high glucosinolate content and the agronomic value, MBG-BRS0057 and MBG-BRS0074 could be good sources of beneficial glucosinolates. The presence of high concentrations of sinigrin, glucoiberin, and glucobrassicin warrant further search into their potential use to enhance the level of these important phytochemicals in these edible crops.     

Bacillus megaterium WZ009催化合成(R)-4-氯-3-羟基丁酸乙酯和(S)-3-羟基-γ-丁内酯

以外消旋4-氯-3-羟基丁酸乙酯为唯一C源的富集培养筛选得到一株菌株WZ009,经16S rDNA测序鉴定为巨大芽胞杆菌(Bacillus megaterium)。B.megaterium WZ009静息细胞可以立体选择性催化(S)-4-氯-3-羟基丁酸乙酯水解和脱氯反应得到光学纯的(R)-4-氯-3-羟基丁酸乙酯(e.e.≥99%)和(S)-3-羟基-γ-丁内酯(e.e.≥95%)。笔者对B.megaterium WZ009不对称催化反应影响因素(温度、pH、中和剂、底物浓度、时间进程以及细胞重复利用)进行优化研究,确定了该反应体系最优条件:底物浓度200 mmol/L,中和剂氨水,pH 7.2,40℃反应12 h,转化率达到50.6%,底物对映体过量值为99.6%。该生物催化合成(R)-4-氯-3-羟基丁酸乙酯和(S)-3-羟基-γ-丁内酯过程具有良好的工业化应用前景。     

含硫、硒化合物在油菜中的积累及其对硫甙水平的影响

温室条件下,对硫胁迫与供硫充足的油菜植株,分别用Ｌ－甲硫氨酸和硒酸盐（ＳｅＯ＾２－４）代替营养液中的硫酸协以及增加ＳＯ＾２－４供应浓度的方法,探讨了不同处理对油菜植株硫甙合成积累的影响,结果说明,增加供硫浓度可明显促进硫甙的合成速率,且在４８ｈ内以两个供硫水平的植株皆呈密切的二次回归递增趋势,ＳｅＯ＾２－４对植株甙的合成积累具有强烈的阻抑效应,并对供硫充足的植株影响更大,４８ｈ内呈直线下降,Ｌ－甲     

Demic structure and its relation with the distribution of an adaptive trait in Danish flea beetles

The flea beetle Phyllotreta nemorum is an oligophagous species using crucifers as host plants. In Denmark two populations have been found which use Barbarea vulgaris ssp. arcuata (G-type) as a host plant, whereas this plant is unsuitable for the survival of the majority of P. nemorum. In the locations in which these two populations occur, alternative host plants are also present. The plants occur in patches, some of which contain a mixture of host plants. In this study of allozyme variation, genetic differentiation between P. nemorum using different host plants in patches in the two different localities was studied hierarchically to assess substructuring of the populations. Evidence was found for low, but significant, amounts of genetic differentiation between (sub)populations using spatially separated plant patches at a distance of approximately 100 m to 1 km (theta = 0.009) and between localities approximately 44 km apart (theta = 0.026), and there was an association between genetic differentiation and geographical distance. No genetic differentiation was found between beetles from different host plants with overlapping local distributions. No evidence was thus found for sympatric host race formation. The geographical distribution of genes enabling P. nemorum to use B. vulgaris as a host plant (100% 'resistant' beetles in samples from B. vulgaris, but much fewer on patches containing only alternative host plants) contrasts with the relatively low amount of genetic differentiation at the neutral allozyme loci. This distribution of 'resistant' beetles (to B. vulgaris defence) is likely to be influenced by local differences in selection and asymmetric gene flow.     

Genetics of the ability of Phyllotreta nemorum larvae to survive in an atypical host plant, Barbarea vulgaris ssp. arcuata

A polymorphism in host plant exploitation has been discovered in the flea beetle, Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) where one resistant population is able to use Barbarea vulgaris R.Br. ssp. arcuata (Opiz.) Simkovics (Brassicaceae) as a host plant while a susceptible population is not. Crosses (F1, F2, and backcrosses) between the two flea beetle populations were made, and survival of the progeny on B. v. ssp. arcuata was measured. The ability of P. nemorum larvae to survive in this plant species depended on the presence of major, dominant genes (R-genes). The two most abundant R-genes in the resistant flea beetle population were X- and Y-linked, respectively. The use of B. v. ssp. arcuata as a natural host plant by the resistant population of P. nemorum seems to be an extension of the host plant range of the species. The role of sex-linked genes in the evolution of host range is discussed.     

Characterization of the Arabidopsis TU8 Glucosinolate Mutation,an Allele of TERMINAL FLOWER2

Glucosinolates are a group of defense-related secondary metabolites found in Arabidopsis and other cruciferous plants. Levels of leaf glucosinolates are regulated during plant development and increase in response to mechanical damage or insect feeding. The Arabidopsis TU8 mutant has a developmentally altered leaf glucosinolate profile: aliphatic glucosinolate levels drop off more rapidly, consistent with the early senescence of the mutant, and the levels of two indole glucosinolates are uniformly low. In TU8 seeds, four long-chain aliphatic glucosinolates have significantly increased levels, whereas the indolyl-3-methyl glucosinolate level is significantly reduced relative to wild type. Genetic mapping and DNA sequencing identified the TU8 mutation as tfl2-6, a new allele of TERMINAL FLOWER2 (TFL2), the only Arabidopsis homolog of animal HETEROCHROMATIN PROTEIN1 (HP1). TU8 (tfl2-6) has other previously identified tfl2 phenotypes, including an early transition to flowering, altered meristem structure, and stunted leaves. Analysis of two additional alleles, tfl2-1 and tfl2-2, showed glucosinolate profiles similar to those of line TU8 (tfl2-6).     

Metabolic engineering of valine- and isoleucine-derived glucosinolates in Arabidopsis expressing CYP79D2 from Cassava

Glucosinolates are amino acid-derived natural products that, upon hydrolysis, typically release isothiocyanates with a wide range of biological activities. Glucosinolates play a role in plant defense as attractants and deterrents against herbivores and pathogens. A key step in glucosinolate biosynthesis is the conversion of amino acids to the corresponding aldoximes, which is catalyzed by cytochromes P450 belonging to the CYP79 family. Expression of CYP79D2 from cassava (Manihot esculenta Crantz.) in Arabidopsis resulted in the production of valine (Val)- and isoleucine-derived glucosinolates not normally found in this ecotype. The transgenic lines showed no morphological phenotype, and the level of endogenous glucosinolates was not affected. The novel glucosinolates were shown to constitute up to 35% of the total glucosinolate content in mature rosette leaves and up to 48% in old leaves. Furthermore, at increased concentrations of these glucosinolates, the proportion of Val-derived glucosinolates decreased. As the isothiocyanates produced from the Val- and isoleucine-derived glucosinolates are volatile, metabolically engineered plants producing these glucosinolates have acquired novel properties with great potential for improvement of resistance to herbivorous insects and for biofumigation.     

Inhibition by prostacyclin and carbacyclins of endothelin-induced DNA synthesis in cultured vascular smooth muscle cells

Effects of prostacyclin and carbacyclins on endothelin-induced DNA synthesis were investigated in vascular smooth muscle cells. DNA synthesis was estimated by [3H]thymidine incorporation. Five carbacyclins used in this report were 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo [3.3.0]oct-2-en-3-yl) pentanoic acid (TEI-7165), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo[3.3.0]oct-2-en-3- yl]pentanoate (TEI-9090), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1-nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)penta noic acid (TEI-9063), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1- nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)pentanoate (TEI-1324), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-4-hydroxy-4-methyl-1- octenyl]bicyclo[3.3.0]oct-2-en-3-yl] pentanoic acid (TEI-3356). Prostacyclin and the carbacyclins inhibited the endothelin-induced DNA synthesis within the nanomolar range. These results suggest that prostacyclin and carbacyclins are possibly effective in inhibiting the proliferation of vascular smooth muscle cells under some situations in vivo.     

Type and concentration of redox reagents influencing nitrile formation upon myrosinase (Brassica carinata)-catalyzed hydrolysis of glucosibarin

The ratio of isothiocyanates (ITCs) to nitriles formed in the myrosinase-catalyzed hydrolysis of glucosinolates is a key factor determining the physiological effect of glucosinolate containing plants and materials. In this context, the mechanism by which nitrile formation occurs is not well understood. In the present paper we have studied the effect of three redox reagents – Fe²⁺, glutathione (GSH) and ascorbic acid – on the profile of products obtained upon the hydrolysis of a model glucosinolate (glucosibarin ((2R)-2-hydroxy-2-phenylethylglucosinolate)) catalyzed by Brassica carinata myrosinase. A Micellar Electrokinetic Capillary Chromatography method that allows following on-line the hydrolysis of the glucosinolate, the formation of the degradation products and the oxidation of GSH was used. Increasing the concentration of Fe²⁺ and GSH (from 0.25- to 2-fold molar excess with respect to the glucosinolate) increased the ratio of nitrile ((2R)-2-hydroxy-2-phenylethylcyanide) to oxazolidine-2-thione ((5S)-5-phenyloxazolidine-2-thione), whereas increasing the concentration of ascorbic acid decreased this ratio. Low concentrations of ascorbic acid favored nitrile formation. A mechanism for nitrile formation involving a disulfide bond in the myrosinase complex is proposed.     

Dialkylaminoalkylnaphthalenes as novel opioid-like analgesics

The study of dialkylaminoalkylnaphthalenes as novel opioid-like analgesics is reported. In particular, the synthesis of (1R,2R/1S,2S)-1-ethyl-1-[2-(6-hydroxynaphthyl)]-1-hydrox-2-m ethyl-2-dimethylaminoethane and its structural analogue (1R,2R/1S,2S)-1-ethyl-1-[2-(6-fluoronaphthyl)]-1-hydroxy-2-methyl- 2-dimethylaminoethane and the configurational analysis by X-ray and 1H NMR spectroscopy are described. Pharmacological profiles are discussed on the basis of the experimental results of analgesia tests (hot plate and writhing test) and rota-rod test, which was performed to distinguish analgesia from drug-induced motor changes. The compounds showed dose-dependent antinociception, with less potency than morphine. Motor coordination appeared to be less involved.     

Suppressive Effect of Yamato-mana (Brassica rapa L. Oleifera Group) Constituent 3-Butenyl Glucosinolate (Gluconapin) on Postprandial Hypertriglyceridemia in Mice

We examined the bioactivity of Yamato-mana (Brassica rapa L. Oleifera Group) constituent glucosinolates and found that 3-butenyl glucosinolate (gluconapin) decreased the plasma triglyceride gain induced by corn oil administration to mice. However, phenethyl glucosinolate (gluconasturtiin) had little effect. 2-Propenyl glucosinolate (sinigrin) also reduced the plasma triglyceride level, which suggests that alkenyl glucosinolates might be promising agents to prevent postprandial hypertriglyceridemia.