Thiophene accumulation in hairy roots ofTagetes patula in response to fungal elicitors

Summary Hairy roots ofTagetes patula were treated with fungal extracts from 3 different fungi. Treated roots were found to accumulate thiophenes at a higher level than untreated control cultures. The kinetics of thiophene formation varied with the fungus from which the elicitor was prepared, elicitor concentration and duration of exposure.     

Thiophenes and benzofurans in the undisturbed rhizosphere ofTagetes patula L.

Summary Marigold (Tagetes patula L.) contains secondary metabolites toxic to various organisms. While these compounds may function as defensive agents in the plant, it is not clear whether they are exuded into the rhizosphere. Using a continuous root exudate trapping system and capillary column gas chromatography/mass spectrometry/data system, four thiophenes and two benzofurans were identified in the root exudates collected from the undisturbed rhizosphere of marigold. The importance of rhizospheric chemistry in the study of allelopathy is stressed.     

Thiophene accumulation in relation to morphology in roots of Tagetes patula

Roots of marigold (Tagetes patula L.) accumulate thiophenes, heterocyclic sulfurous compounds with strong biocidal activity. In detached roots cultured in vitro, the thiophene content was 5 mol·(g fresh weight)^-1 which is 25-times higher than in roots attached to the plant. In roots derived from tissues transformed by Agrobacterium tumefaciens and A. rhizogenes, the morphology and thiophene content varied with the bacterial strain used. Transformation stimulated the elongation of the root tips and the formation of lateral roots but lowered the thiophene level to 20–50% relative to the concentration in untransformed detached roots. A negative correlation was found between the number of laterals in a root system and the thiophene content. Extensive branching and a decrease in thiophene accumulation was evoked in untransformed roots by indole-3-acetic acid (1–10 mol·l^-1) added to the medium. Within the roots, the highest thiophene concentrations were found in the tips. The results indicate that auxin directly or indirectly plays a role in the regulation of the thiophene level in root tips.Abbreviations B5 Gamborg's B5 medium - IAA Indole-3-acetic acid     

Thiophene acetylenes from Leuzea roots

The isolation and identification of four polyacetylenes is reported from the roots of Leuzea carthamoides. The compounds belong to a uniform series of thiophene acetylenes two of the compounds are new, whereas two are already known.     

Thiophene synthesis and distribution in young developing plants of Tagetes patula and Tagetes erecta

Thiophene synthesis and accumulation were investigated in organsof Tagetes patula and T. erecta. Thiophene accumulation startedrapidly in germinating seedlings of both species. Roots andhypocotyls were the major thiophene accumulating organs and5-(3-buten-1-ynyl)-2, 2-bithienyl (BBT) and 5-(4-acetoxy-1-butynyl)-2,2 -bithienyl (BBTOAc) were the major accumulated compounds.Higher thiophene concentrations were reached in Tagetes patulathan in T. erecta. Accumulation patterns for individual thiopheneswere different within organs, between organs and between bothspecies. Within hypocotyls of Tagetes patula, thiophene concentrationswere high in the epidermis and the vascular tissue and low inthe parenchymatic tissues of cortex and pith. Synthesis of thiopheneswas high in the roots and hypocotyls and very low in the leaves.Transport of thiophenes from the roots into the shoot occurred,but the rate of transport was too low to explain the high concentrationsin the hypocotyl. It is concluded that for the main part thiophenesare accumulated where they are synthesized. Key words: Tagetes, hiophenest, synthesis, accumulation, secondary metabolites     

Thiophene production in transformed roots cultures of Tagetes filifolia

Transformed root cultures of Tagetes filifolia were established by infection with Agrobacterium rhizogenes LBA 9402. Several clones were obtained with different growth index, content of thiophenes and pattern. The isolated clones showed considerable variations in total thiophene content (27 to 11764 g/g fresh weight) but all had similar patterns of the different thiophenes. Only one clone excreted thiophenes (about 80% of total amount). © Rapid Science Ltd. 1998     

Elicitation of thiophene production by cultured hairy roots of Tagetes patula

Hairy roots of Tagetes patula were initiated by infecting the seedlings with Agrobacterium rhizogenes. The hairy roots were grown in liquid medium MS (Murashige and Skoog 1962) supplemented with sucrose. The roots were treated with three different elicitors obtained from mycelial culture of Aspergillus niger, Rhizopus oligosporus and Pencillium notatum. Accumulation of biomass and the production of thiophenes were studied over a period of six weeks in culture. The HPLC separation profile of the thiophenes indicated the presence of several structurally different thiophenes. α-terthienyl being predominent. Maximum production of thiophene was recorded at the end of the fourth week in culture with a content of 0.138 % (w/w on dry weight basis). Treatment of hairy roots with mycelial extract of Aspergillus niger (1.5 % v/v) elicited an increase in thiophene content by 1.6 folds over the control.     

Production of nematocidal compounds by hairy root cultures of Tagetes patula L.

Summary Marigold (Tagetes patula L.) hairy roots induced by infection with Agrobacterium rhizogenes produced -terthienyl when grown in darkness, and an n-hexane extract of the roots showed nematocidal activity. Depending on the hairy root line used, the level of -terthienyl varied from 15 to 1268 g per g dry weight, a level that corresponded to 0.15 to 12.7-fold that in intact roots. Analysis by HPLC indicated that the nematocidal activity was due predominantly to -terthienyl. However, it is suggested that nematocidal compounds other than -terthienyl are present in hairy roots cultured in the dark for long periods or in the light.     

Biosynthesis of thiophenes in Tagetes patula.

The biosynthesis of 5-(3-buten-1-ynyl)-2,2'-bithiophene was studied in root cultures of Tagetes patula. Organ cultures were grown with [U-13C(6)]glucose or [1-13C]glucose. The bithiopene and amino acids from cell protein were isolated and analysed by quantitative NMR spectroscopy. Retrobiosynthetic analysis establish acetyl-CoA or a closely related compound (e.g. malonyl-CoA) as building blocks and their orientations in the bithiophene. The data confirm a previously suggested biosynthetic route via long-chain fatty acids and polyacetylenes. However, a polyketide-like biosynthesis via a carbocyclic intermediate cannot be excluded.     

Investigation of P and S Distributions in the Roots of Tagetes patula L. using Micro-PIXE

A proton microprobe for energy-dispersive PIXE-analysis hasbeen used to measure elemental distributions of sulphur andother elements in roots of Tagetes patula L. by making a line-scanalong the diameter of the cross-section. Higher concentrationsof phosphorus and sulphur were found in or near the phloem.In addition the endodermis contained an increased sulphur concentration.The results obtained and future possibilities for this kindof investigation are discussed. Key words: Tagetes patula L., micro-PIXE, sulphur, thiophenes, endodermis, Pratylenchus penctrans (Cobb)     

Polyphenol oxidase in the roots ofCucurbita pepo L.

Z ko?en? tykveCucurbita pepo L., sorta ?Kaba?ky”, byl získán acetonový preparát, který má polyfenoloxydásovou aktivitu v??i pyrogallolu, podstatně men?í v??i pyrokatechinu ?i DOPA. Je kompetitivně inhibován DIECA, dále KCN, není inhibován NaN₃, co? svěd?í pro Cu-enzym polyfenoloxydasového typu. Kvantitativní rozdíly mezi variantami ?NS” a ?-Ca” nebyly zji?těny, kvalitativní rozdíly, dané afinitou v??i substrátu, nejsou pr?kazné.     

Cell surface inCalluna vulgaris L. hair roots

Summary Calluna vulgaris possesses small roots called hair roots, which in natural conditions are colonized by symbiotic mycorrhizal fungi. A specialized cell surface-consisting of the cell wall and the overlaying mucilage-has been hypothesized to be important for the establishment of ericoid mycorrhizae. In this work the cell surface of hair roots of plants growing in sterile conditions has been characterized by using in situ techniques, integrated when possible, by biochemical analysis. The mucilage is abundant around the apex, while it becomes thinner and thinner on the differentiated parts. Sugar residues such as mannose, glucose and galactose are regularly distributed along the whole root length, while N-acetylglucosamine residues are limited to the differentiated part of the hair root. Cellobiohydrolase-gold complex, used to reveal -1, 4-glucans, regularly labels mucilage and cell walls of apical and differentiated regions. Polygalacturonic acids revealed by monoclonal antibodies are found at the surface of the cap cells and on the cell walls of the inner tissues in the differentiated zones, but never at the surface of the epidermal cells.The labeling continuity between mucilage and cell walls demonstrates that some molecules such as -1, 4-glucans are common to the two compartments, but probably have a different status of aggregation. On the contrary, other molecules, such as N-acetylglucosamine or polygalacturonic acid display a precise pattern of localization following root differentiation.Abbreviations FITC fluorescein isothiocyanate - WGA wheat germ agglutinin - Con A concanavalin A - RCA₁₂₀ Ricinus communis agglutinin - UEA Ulex europaeus agglutinin - CBH I cellobiohydrolase I - TEM transmission electron microscopy - MeNH₂ methylamine - PATAg periodic acid-thiocarbohydrazide-silver proteinate reaction - PAS periodic acid-Schiff reaction     

Effect of the physiological-biochemical characteristics variability on a radiosensitiveness of the Atriplex patula L. and Artemisia vulgaris L. ecoforms

On the example of the physiological and the cytology-biochemical characteristics variability of an Atriplex patula L. and Artemisia vulgaris L. sprouts which parental plants were generated in various environmental conditions (South Yakutia, the Central Yakutia, Middle Ural), was shown, that radiostability depends not only on set protective antioxidant, on the DNA-reparation systems and on the vulnerability degree of a functioning genome, but also on the phenotypic diversifications of a population which in turn, in the certain degree, are consequence of previous selection of a population to all set of ecological stresses-factors of the environment.     

The quiescent centre in excised roots ofPisum sativum L.

Protoplasma - Excised roots ofPisum sativum were cultured in White's medium supplemented with various concentrations of sucrose or IAA and exposed to3H-TdR for 24 hours, three days after...     

Conformational interconversion in protein crystals.

We present evidence that the structure of carbonmonoxy myoglobin crystals can be altered by lowering the pH. This structural change is monitored by the characteristic Fe-CO Raman modes at 508 and 491 cm-1 and is thought to involve a localized distal pocket transition from a "closed" conformation at pH 7 to a more "open" conformation at pH 4. These changes take place in the crystal without loss of intensity of a conformationally sensitive Raman mode at 252 cm-1 that signals a partial unfolding of the globin structure in solution. Quantitative studies, which monitor the open and closed populations as a function of laser photolysis, demonstrate that the interconversion rates (k+/-) in solution at 298 K are fast compared to the photolysis and CO entry rates (i.e. k+/- much greater than 10(3) s-1), while in frozen samples the interconversion is much slower than the experimental time scale (minutes). Since the open conformation is a minority species at pH 7, rapid exchange in aqueous solution is a necessary condition for this species to play a functional role. In the crystal, the interconversion rates are slowed compared to solution and begin to approach the photolysis rate (i.e. k+/- approximately 10(3) to 10(4) s-1). This indicates that the barriers for conformational exchange are increased in the crystal environment, compared to the solution, apparently due to the packing forces of the surrounding molecules. X-ray and neutron diffraction studies of MbCO crystals at high and low pH are needed to characterize the details of the structural changes and to test the hypothesis that closed and open distal pocket structures are associated with the 508 and 491 cm-1 Fe-CO modes.     

Production of thiophenes from callus cultures of Tagetes patula L. and its mosquito larvicidal activity

Calli were initiated from leaf tissues of T. patula, on Murashige and Skoog's medium supplemented with 2-4 dichlorophenoxacetic acid (2,4-D) and kinetin (Kn). The maximum accumulation of biomass was recorded on 6th week at 1.11 g. dry wt/culture. Maximum thiophene content was recorded on 4th week at 0.008% on dry wt basis in callus cultures of T. patula subjected to nutrient stress. Nitrogen stress induced 3-fold increase in thiophene production level in six weeks (0.024% on dry weight basis). The best hormonal supplementation required for thiophenes production was found to be 2,4-D (2.0 mg L(-1)) and kinetin (2.0 mg L(-1)). The thiophenes produced in callus cultures of T. patula showed larvicidal effect against mosquito larvae.