TRANSFORMATION OF Lotus corniculatus L.MEDIATED BY Agrobacterium tumefaciens

A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that contained a non-oncogenic Ti plasmid vector. The vector carried a chimaeric npt-Ⅱ gene and a nopaline synthase gene (nos). On the selective medium that contained kanamycin, 40% of the explants formed buds within 3 weeks. Developed shoots were cut off and transferred to rooting medium. Normal-looking plants were recovered and grew well after being transplanted into soil, bloomed and set seeds. Foreign genes were integrated onto the L. corniculatus genome, expressed, and inherited through sexual reproduction, which was proven by nopaline detection, NPT-Ⅱ enzyme activity detection and DNA hybridization test of the transformed plants and the nopaline detection of the progeny.     

Simultaneous qualitative and quantitative analysis of flavonoids and alkaloids from the leaves of Nelumbo nucifera Gaertn. using high‐performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

A reliable method, combining qualitative analysis by high‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry and quantitative assessment by high‐performance liquid chromatography with photodiode array detection, has been developed to simultaneously analyze flavonoids and alkaloids in lotus leaf extracts. In the qualitative analysis, a total of 30 compounds, including 12 flavonoids, 16 alkaloids, and two proanthocyanidins, were identified. The fragmentation behaviors of four types of flavone glycoside and three types of alkaloid are summarized. The mass spectra of four representative components, quercetin 3‐O‐glucuronide, norcoclaurine, nuciferine, and neferine, are shown to illustrate their fragmentation pathways. Five pairs of isomers were detected and three of them were distinguished by comparing the elution order with reference substances and the mass spectrometry data with reported data. In the quantitative analysis, 30 lotus leaf samples from different regions were analyzed to investigate the proportion of eight representative compounds. Quercetin 3‐O‐glucuronide was found to be the predominant constituent of lotus leaf extracts. For further discrimination among the samples, hierarchical cluster analysis, and principal component analysis, based on the areas of the eight quantitative peaks, were carried out.     

Toward Superhydrophobic Polydimethylsiloxane−Silica Particle Coatings

Hydrophobized silica nanoparticles of different sizes, from 16 to 500 nm, were used to impart roughness to a hydrophobic polydimethylsiloxane (PDMS) coating with the aim of obtaining superhydrophobic properties. The particle silanization process and the curing process of the PDMS coating were optimized to increase the contact angle (CA) of the particle containing coating. The evaluation of the coatings, by means of water CA measurements and scanning electron microscopy imaging, shows that superhydrophobicity in the adhesive rose state was achieved using combinations of two differently sized particles, with an excess of the small 16 nm ones. Superhydrophobicity in the lotus state was obtained when the filler concentration of 16 nm particles was 40 wt%, but under such conditions the coating was found to partially crack, which is detrimental in barrier applications. The preference for the rose wetting state can be explained by the round shape of the particles, which promotes the superhydrophobic rose wetting state over that of the superhydrophobic lotus state.     

Simultaneous qualitative assessment and quantitative analysis of flavonoids in various tissues of lotus (Nelumbo nucifera) using high performance liquid chromatography coupled with triple quad mass spectrometry

Flavonoid composition and concentration were investigated in 12 different tissues of ‘Ti-1’ lotus (Nelumbo nucifera) by high performance liquid chromatography equipped with photodiode array detection tandem electrospray ionization mass spectrometry (HPLC-DAD-ESI-MSⁿ). A total of 20 flavonoids belonging to six groups (myricetin, quercetin, kaempferol, isohamnetin, diosmetin derivatives) were separated and identified. Myricetin 3-O-galactoside, myricetin 3-O-glucuronide, isorhamnetin 3-O-glucuronide and free aglycone diometin (3′,5,7-trihydroxy-4′-methoxyflavone) were first reported in lotus. Flavonoid composition varied largely with tissue type, and diverse compounds (5–15) were found in leaf and flower stalks, flower pistils, seed coats and embryos. Flower tissues including flower petals, stamens, pistils, and, especially, reproductive tissue fruit coats had more flavonoid compounds (15–17) than leaves (12), while no flavonoids were detectable in seed kernels. The flavonoid content of seed embryos was high, 730.95 mg 100 g⁻¹ DW (dry weight). As regards the other tissues, mature leaf pulp (771.79 mg 100 g⁻¹ FW (fresh weight)) and young leaves (650.67 mg 100 g⁻¹ FW) had higher total flavonoid amount than flower stamens (359.45 mg 100 g⁻¹ FW) and flower petals (342.97 mg 100 g⁻¹ FW), while leaf stalks, flower stalks and seed coats had much less total flavonoid (less than 40 mg 100 g⁻¹ FW).     

Application of ionic liquids based microwave-assisted extraction of three alkaloids N-nornuciferine, O-nornuciferine, and nuciferine from lotus leaf

The application of ionic liquids based microwave-assisted extraction (ILMAE) was successfully developed for extracting three alkaloids N-nornuciferine, O-nornuciferine, and nuciferine from lotus leaf. Seven kinds of 1-alkyl-3-methylimidazolium with different cations and anions were investigated in this work and 1.0 M 1-hexyl-3-methylimidazolium bromide ([C₆MIM]Br) solution was selected as solvent. In addition, the microwave parameters including irradiation power, extraction time and solid-liquid ratio were optimized. Compared with the regular MAE and conventional heat-reflux extraction (HRE), the proposed approach exhibited higher efficiency (0.9-43.7% enhanced) and shorter extraction time (from 2 h to 2 min), which indicated ILMAE was an efficient, rapid and simple sample preparation technique. Moreover, the proposed method was validated by the linearity, reproducibility, and recovery experiments. Good linearity was observed with the regression coefficients (r²) between 0.9998 and 0.9999. The recoveries of all methods were in the range of 94.6% and 105.5% with RSD lower than 6.6%, which indicated that the proposed method was credible.     

Superhydrophobic wind turbine blade surfaces obtained by a simple deposition of silica nanoparticles embedded in epoxy

Samples of wind turbine blade surface have been covered with a superhydrophobic coating made of silica nanoparticles embedded in commercial epoxy paint. The superhydrophobic surfaces have a water contact angle around 152°, a hysteresis less than 2° and a water drop sliding angle around 0.5°. These surfaces are water repellent so that water drops cannot remain motionless on the surface. Examination of coated and uncoated surfaces with scanning electron microscopy and atomic force microscopy, together with measurements of water contact angles, indicates that the air trapped in the cavity enhances the water repellency similarly to the lotus leaf effect. Moreover, this new coating is stable under UVC irradiation and water pouring. The production of this nanoscale coating film being simple and low cost, it can be considered as a suitable candidate for water protection of different outdoor structures.     

A new galloyl glycoside from Lotus corniculatus

A new galloyl glucoside, 2,6-di-O-acetyl 1-O-galloyl β-D-glucose (1), along with five known phenolic compounds were isolated from the whole plants of Lotus corniculatus. Their structures were elucidated by means of extensive spectroscopic analysis. Compound 1 was assessed for its cytotoxicity against five human tumour lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), and the result showed that it had no activity.     

荷叶表面纳米结构与浸润性的关系

通过烘烤、化学萃取及物理剥除等方法改变荷叶表面的纳米结构和化学组成, 在环境扫描电镜(ESEM)和全反射红外光谱(ATR)对样品的微观形貌和化学组成进行表征的基础上, 为消除其它外界因素影响样品的真实微观形貌, 进一步采用原子力显微镜(AFM)进行了表征. 通过测量不同处理方法所得样品的表观接触角表征了样品的浸润性质. 结果表明, 荷叶表面的蜡质是产生表面疏水性的根本原因, 其微米级结构放大了其疏水性, 而纳米结构是导致其表面高接触角、低滚动角, 即“荷叶效应”的关键原因.     

Superhydrophobic nanostructures based on porous alumina

Superhydrophobic polytetrafluoroethylene (Teflon®, DuPont) sub-micro and nanostructures were fabricated by the dipping method, based on anodization process in oxalic acid. The polymer sticking phenomenon during the replication creates the sub-microstructures on the negative polytetrafluoroethylene nanostructure replica. This process gives a hierarchical structure with nanostructures on sub-microstructures, which looks like the same structures as lotus leaf and enables commercialization. The diameter and the height of the replicated nano pillars were 40 nm and 40 μm respectively. The aspect ratio is approximately 1000. The fabricated surface has a semi-permanent superhydrophobicity, the apparent contact angle of the polytetrafluoroethylene sub-micro and nanostructures is about 160°, and the sliding angle is less than 1°.     

A new method for producing “Lotus Effect” on a biomimetic shark skin

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a superhydrophobic dual-biomimetic surface comprising both the shark-skin surface morphology and the lotus leaf-like hierarchical micro/nano-structures. The biomimetic surface possessing shark-skin pattern microstructure was first fabricated by microreplication of shark-skin surface based on PDMS; and then it was treated by flame to form hierarchical micro/nano-structures that can produce lotus effect. The fabricated biomimetic surfaces were characterized with scanning electron microscopy (SEM), water contact angle measurements and liquid drop impact experiments. The results show that the fabricated dual-biomimetic surface possesses both the vivid shark-skin surface morphology and the lotus leaf-like hierarchical micro/nano-structures. It can exhibit excellent superhydrophobicity that the contact angle is as high as 160° and maintain its robustness of the superhydrophobicity during the droplet impact process at a relatively high Weber number. The mechanism of the micromorphology evolution and microstructural changes on the biomimetic shark-skin surface was also discussed here in the process of flame treatment. This method is expected to be developed into a novel and feasible biomimetic surface manufacturing technique.