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In plants, cytochrome P450s are monooxygenase that play key roles in the synthesis and degradation of intracellular substances. In tobacco, the majority of studies examining the P450 superfamily have concentrated on the CYP82E subfamily, where multiple family members function as demethylases, facilitating the synthesis of nornicotine. In this study, NtCYP82C4, a tobacco P450 superfamily member, was identified from a gene-edited tobacco mutant that nicotine biosynthesis in tobacco leaves is evidently reduced. Compared to the wild-type plants, the knockout of NtCYP82C4 resulted in a significantly lower nicotine content and biomass in tobacco leaves. Transcriptome and metabolome analyses indicated that the knockout of NtCYP82C4 inhibites secondary metabolic processes in tobacco plants, leading to the accumulation of some important precursors in the nicotine synthesis process, including aspartic acid and nicotinic acid, and increases nitrogen partitioning associated with those processes such as amino acid synthesis and utilization. It is speculated that NtCYP82C4 may function as an important catalase downstream of the nicotine synthesis. Currently, most of the steps and enzymes involved in the nicotine biosynthesis process in tobacco have been elucidated. Here, our study deepens the current understanding of nicotine biosynthesis process and provides new enzyme targets for nicotine synthesis in tobacco plants.

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Nicandra physaloides is a medicinal and edible plant and has been used as traditionally herbal medicine to treat various diseases in folk. Its characteristic withanolides, a kind of ergostane-type steroids, are reported to display plentiful biological activities that many explain the effect of N. physaloides to some extent. Thus, to further find bioactive steroids, the stems and leaves of N. physaloides were investigated and three new C23 steroids, nic-physatones I-J (1-2), and nic-physatone S (3), together with a known C25 steroid, nic 17 (4), were isolated. Their structures were elucidated by extensive 1D NMR and 2D NMR (HSQC, HMBC, 1H-1H COSY, and ROESY), UV and MS analyses. Compounds 1-3 possess a rare C23 steroid skeleton. Among them, compound 3 represented the first example of a C23 steroid featuring a benzene ring (D ring). The isolated compounds showed no cytotoxic activity.

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The easy shrinkage and swelling of polymer monolithic column when exposed to mobile phase with different polarity is a problem that cannot be ignored. To overcome this drawback, a convenient aqueous two-phase polymerization approach was used to prepare poly (polyethylene glycol diacrylate, PEGDA) monolithic porous layer open tubular (mono-PLOT) columns (150 µm). The poly(PEGDA) mono-PLOT column with homogeneous polymer porous layer was synthesized successfully. A maximum plate number of 41,500 plates per meter for allyl thiourea was obtained under a velocity of 1.8 mm/s. Several kinds of polar molecule were separated on the proposed mono-PLOT column and a typical hydrophilic interaction retention mechanism was observed. High speed separation of benzoic acids was also carried out, baseline separation of five benzoic acids was successfully achieved within 5 min with a 70 cm mono-PLOT column at 50°C. Furthermore, the resulting PLOT column was also successfully applied to separate standard analytes of three DNA oxidative damage products and RNA-modified nucleosides and four chlorophenols. At last, the column could separate alcohols, alkanes, and aromatic isomers via GC. It had more than 20,000 plates per meter for butanol - higher than commercial coatings open tubular columns.

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A CoII coordination polymer built from a mixed azide and zwitterionic pyridinium ions and its temperature-dependent magnetic properties are described. We used the Markov chain Monte Carlo (MCMC) method to fit the data, and found the following results: (1) there are strong correlations between the model parameters; (2) the data at above 28 K are well fitted by the magnetism model.

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Oryzaeins A-D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayed moderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 µM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 µM. Supporting information available online at http://www.thieme-connect.de/products.

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Two new benzolactones, 5-methyl-6-prenyl-isobenzofuran-1(3H)-one (1), 5-hydroxymethyl-6-prenyl-isobenzofuran-1(3H)-one (2), together with four known phenolic compounds (3-6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1-6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1-6 exhibited high anti-TMV activities with inhibition rates in the range of 16.9-26.2%, respectively.

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The design of porous bimetallic nanocrystals (NCs) is very important for electrochemical energy conversion. Herein, we report an aqueous solution method for one-step fabrication of porous PtCu NCs assembled by spatially interconnected arms in high yield by a simple ultrasonic treatment of the reaction mixture at room temperature. The proposed method, without the need for multi-step synthesis, high temperatures, and organic solvents, shows an obvious advantage of simplicity for the feasible synthesis of bimetallic PtCu NCs with a porous structure. The as-made porous PtCu NCs are highly active and durable catalysts for the methanol oxidation reaction due to their porous structure and bimetallic composition.

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Four new flavones, tobaflavones E-H (1-4), together with two known flavones (5 and 6), were isolated from the leaves of Dali Tiandeng tobacco (a variety of Yunnan local air cured tobacco). Their structures were elucidated by spectroscopic methods, including extensive 1D- and 2D NMR techniques. Compound 2 is the first naturally occurring flavone bearing a (4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)methyl moiety. These compounds were also evaluated for their anti-tobacco mosaic virus (anti-TMV) activity. The results revealed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rate of 35.3% and 39.6%, respectively. The rates are higher than those of positive control. The other compounds also showed potential anti-TMV activity with inhibition rates in the range of 18.7-28.4%, respectively.

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In the title complex, [Mn(N(3))(2)(C(8)H(8)N(6))(2)], the complete molecule is generated by the application of twofold symmetry, and is in a distorted octa-hedral environment, coordinated by four N atoms of two bidentate 6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine ligands and two N atoms from two azide anions. The two chelated 6-(pyridin-2-yl)-1,3,5-triazine-2,4-diamine ligands form a dihedral angle 74.75 (5)°. The mononuclear mol-ecules are alternatively linked into layers parallel to the ac plane via N-H⋯N hydrogen bonds. Adjacent layers are connected into a three-dimensional supra-molecular framework by futher N-H⋯N hydrogen-bonding inter-actions.

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The title compound, [Co(C(7)H(5)O(2))(2)(C(12)H(16)N(3)O(2))(2)(H(2)O)(2)], was obtained from a conventional solvent evaporation method. The complex mol-ecule is centrosymmetric, so pairs of equivalent ligands lie trans to each other in a slightly distorted octa-hedral CoN(2)O(4) geometry. The Co(II) ion is coordinated by the pyridine N atoms from NITpPy ligands [NITpPy is 4,4,5,5-tetra-methyl-2-(pyridin-4-yl)imidazoline-1-oxyl 3-oxide), water O atoms and two monodentate benzoate O atoms. The complex mol-ecules are connected by O-H⋯O hydrogen bonds between water mol-ecules and benzoate ligands, forming chains parallel to [100]. π-π stacking inter-actions between the benzoate ligands with centroid-centroid distances of 3.752 (2) Šconnect the chains into layers parallel to (10-1).

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In the polymeric title complex, {[Mn(O(2)CC(6)H(4)-p-OH)(2)(C(10)H(8)N(2))]·C(10)H(8)N(2)·2H(2)O}(n), the Mn(II) atom is coordinated in a distorted octa-hedral geometry defined by four O atoms from three different carboxyl-ate ligands and two trans-N atoms from two 4,4'-bipyridine ligands. In the crystal structure, an extensive range of O-H⋯O and O-H⋯N hydrogen bonds link the complex and all non-coordinated mol-ecules into a three-dimensional network.

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In the title compound, C(11)H(10)ClN(3)S, the dihedral angle between the benzene and pyrimidine rings is 3.99 (4)°. In the crystal, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into ribbons of R(2) (2)(8) rings parallel to [100]. Weak C-H⋯S contacts connect adjacent ribbons into a two-dimensional undulating layer-like structure extending parallel to (110). The benzene and pyrimidine rings of adjacent mol-ecules have the offset face-to-face π-π stacking inter-actions in a zigzag fashion along the c axis, with perpendicular ring distances of 3.463 and 3.639 Å, and a dihedral angle between the planes of 3.99 (2)°. The distance between the ring centroids is 4.420 (2) Å.