New SERS feature of β‐carotene: consequences for quantitative SERS analysis

While recording SERS spectra of pure β‐carotene at sub‐micromole concentrations for reference purpose, we discovered an unusual spectral response never reported before. In pre‐resonance conditions with the 532‐nm line, SERS of β‐carotene with AgNPs exhibits among the strong υ(CC) mode at 1512 cm⁻¹ unshifted from normal Raman spectrum, additional strong bands at 1649, 1575 and 1387 cm⁻¹ as well as other medium bands not observed in the Raman spectrum of the crystalline powder. Such behavior is explained in terms of selection rules relaxation upon cyclohexene terminal rings of the β‐carotene interaction with the NP surface. AFM images of the SERS system suggested dimers and trimers clustering of the nanoparticles with adsorbed β‐carotene. In light of the new SERS feature the consequences in correct interpretation of the SERS imaging from complex biosystems containing carotenoids are discussed. Relative intensity ratio of the β‐carotene band at 1512 cm⁻¹ and water against concentration allowed a reliable SERS calibration curve for 50 to 500 nmol l⁻¹ concentration range and provided quantitative SERS assessment of the carotenoid content in the sea urchin (Paracentrotus lividus) gonads extracts. Copyright © 2015 John Wiley & Sons, Ltd.     

培养基组成对光合细菌产生类胡萝卜素的影响

讨论了不同的碳源、氮源、无机盐组成的培养基对沼泽红假单胞菌B@9菌株色素组成、相对含量、存在状态的影响.结果表明,碳源、氮源、无机盐均能引起光合菌B@9菌株类胡萝卜素的合成、积累及其组成的变化,其中,碳源和氮源的影响更大.     

Solvatochromism of 2‐(N,N‐dimethylamino)‐7‐nitrofluorene and the natural dye β‐carotene: application for the determination of solvent dipolarity and polarizability

The effects of solvents on chemical phenomena (rate and equilibrium constants, spectroscopic transitions, etc.) are conveniently described by solvation free‐energy relationships that take into account solvent acidity, basicity and dipolarity/polarizability. The latter can be separated into its components by manipulating the UV–vis spectra of two solvatochromic probes, 2‐(N,N‐dimethylamino)‐7‐nitrofluorene (DMANF) and a di‐(tert‐butyl)‐tetramethyl docosanonaen probe (ttbP9) whose synthesis is laborious and expensive. Recently, we have shown that the natural dye β‐carotene can be conveniently employed instead of ttbP9 for the determination of solvent polarizability (SP) of 76 molecular solvents and four ionic liquids. In the present work, we report the polarizabilities of further 24 solvents. Based on the solvatochromism of β‐carotene and DMANF, we have calculated solvent dipolarity (SD) for 103 protic and aprotic molecular solvents, and ionic liquids. The dependence of SD and SP on the number of carbon atoms in the acyl‐ or alkyl group of several homologous series (alcohols; 2‐alkoxyethanols; carboxylic acid‐ anhydrides, and esters, ionic liquids) is calculated and briefly discussed. Copyright © 2013 John Wiley & Sons, Ltd.     

Vitamin A and Bone Health: A Review on Current Evidence

Vitamin A is a fat-soluble micronutrient essential for growth, immunity, and good vision. The preformed retinol is commonly found in food of animal origin whereas provitamin A is derived from food of plant origin. This review summarises the current evidence from animal, human and cell-culture studies on the effects of vitamin A towards bone health. Animal studies showed that the negative effects of retinol on the skeleton were observed at higher concentrations, especially on the cortical bone. In humans, the direct relationship between vitamin A and poor bone health was more pronounced in individuals with obesity or vitamin D deficiency. Mechanistically, vitamin A differentially influenced the stages of osteogenesis by enhancing early osteoblastic differentiation and inhibiting bone mineralisation via retinoic acid receptor (RAR) signalling and modulation of osteocyte/osteoblast-related bone peptides. However, adequate vitamin A intake through food or supplements was shown to maintain healthy bones. Meanwhile, provitamin A (carotene and β-cryptoxanthin) may also protect bone. In vitro evidence showed that carotene and β-cryptoxanthin may serve as precursors for retinoids, specifically all-trans-retinoic acid, which serve as ligand for RARs to promote osteogenesis and suppressed nuclear factor-kappa B activation to inhibit the differentiation and maturation of osteoclasts. In conclusion, we suggest that both vitamin A and provitamin A may be potential bone-protecting agents, and more studies are warranted to support this hypothesis.     

沼泽红假单胞菌类胡萝卜素的提取和分析

对沼泽红假单胞菌B.9菌株（RhodopseudomonasPal-ustrisstrainB．9）类胡萝卜素的提取进行了研究。用超声波破碎菌体,类胡萝卜素得量较高;菌体中类胡萝卜素用丙酮提取,提取效果因菌体量、丙酿用量而变;提取波经革取、皂化。洗涤得类胡萝卡素粗制品,对其分析表明B．9菌株含有螺菌黄素系列的类胡萝卜素,     

胡萝卜素产生菌原生质体诱变育种的研究

采用原生质体制备技术与单一因素多次诱变育种相结合的育种技术，对产胡萝卜素酵母原生质体进行诱变处理，选育出一株比亲株胡萝卜素产量高１．６倍的新菌株     

Growth profile of stimulated Raman anti‐Stokes scattering influenced by fluorescence seeding in liquid‐core optical fiber

We demonstrated the growth profile of stimulated Raman anti‐Stokes scattering (SRS) of carbon disulfide (CS₂) influenced by fluorescence seeding of all‐trans‐β‐carotene and rhodamine‐B (RhB) in liquid‐core optical fiber (LCOF). The pump energy which was needed to build up the first‐order anti‐Stokes radiation of CS₂ solutions with the fluorescence seeding was lower than that of CS₂ solutions without fluorescence seeding because of the fluorescence enhancement effect on the intensity of the first‐order Stokes radiation. The first‐order anti‐Stokes radiation of the RhB solution (10⁻⁸ M ) was built up at a lower pump energy than that of the all‐trans‐β‐carotene solution (10⁻⁶ M ), and the intensity of the first‐order anti‐Stokes radiation of the RhB solution was higher than that of the all‐trans‐β‐carotene solution. Simultaneously, the coupled wave differential equations were obtained by the theoretical derivation, and the growth profile of the first‐order anti‐Stokes radiation was theoretically calculated with and without the fluorescence seeding by these equations. Copyright © 2009 John Wiley & Sons, Ltd.     

1H HR-MAS NMR of carotenoids in aqueous samples and raw vegetables

Carotenoids are linear C40 tetraterpenoid hydrocarbons and represent a wide category of natural pigments. They are components of the pigment system of chloroplasts and are involved in the primary light absorption and the photon canalization of photosynthesis. Moreover, they also behave as quenchers of singlet oxygen, protecting cells and organisms against lipid peroxidation.Carotenoids have a strong lipophilic character and are usually analyzed in organic solvents. However, because of their biological activity, the characterization of these compounds in an aqueous environment or in the natural matrix is very important.One of the most important dietary carotenoids is beta-carotene, which has been extensively studied both in vivo and in model systems, but because of the low concentration and strong interaction with the biological matrix, beta-carotene has never been observed by NMR in solid aqueous samples.In the present work, a model system has been developed for the detection and identification of beta-carotene in solid aqueous samples by 1H HR-MAS NMR. The efficiency of the model has led to the identification of beta-carotene in a raw vegetable matrix.     

盐生杜氏藻cbr基因的克隆

首先对其他物种cbr／elip基因的同源序列进行相似性分析,设计一对简并引物,利用TR—PCR技术获得-250bp的片段,经克隆测序分析发现其同D．bardwail的cbr基因有67．0％的同源性,然后再以此片段为模板设计引物,通过RACE技术构建盐生杜氏藻cbr基因的全长序列．     

A stable ‘sandwich’ system of Surface‐Enhanced Resonance Raman Scattering for the analysis of β‐carotenes in a photosynthetic pigment‐protein complex

In plants, Photosystem I (PSI) is composed of a core complex and a membrane‐associated antenna complex light‐harvesting complex I that captures light and funnels its energy to the core complex. To obtain Raman structural information on β‐carotenes embedded in the PSI core complex, a ‘sandwich’ system of roughened silver slice: target protein complexes: single silver nanoparticles was fabricated for Surface‐Enhanced Resonance Raman Scattering (SERRS) measurements. This study provided a method to overcome spectral irreproducibility, which is the main drawback of Surface‐Enhanced Raman Scattering/SERRS‐based studies. The Raman spectra of β‐carotenes embedded in the PSI core complex can be obtained at very low sample concentrations (1–5 µg Chl/ml) and high signal/noise ratios. The β‐carotenes in the spinach PSI core complex were predominantly all‐trans configuration. The membrane protein‐mediated adsorption of silver nanoparticles induced the uniform distribution of a large number of single nanoparticles, which contributed to achieving highly reproducible SERRS spectra. This study is the first to apply single silver nanoparticle‐based SERRS analysis in membrane proteins. Copyright © 2013 John Wiley & Sons, Ltd.