The effect of CPTA analogs and other nitrogenous compounds on the biosynthesis of carotenoids in Phycomyces blakesleeanus mutants

The inhibitory effect of a series of analogs of CPTA, 2-(4-chlorophenylthio)-triethylamine-HCl, and ammonia derivatives on carotenoid biosynthesis in Phycomyces blakesleeanus mutants was studied. The types of inhibition exhibited allowed no firm conclusions about the biosynthetic route to β-carotene from either β-zeacarotene or lycopene. However, the evidence suggests at present that both pathways are operative. It was found that a slight change in structure of inhibitor resulted in a different type of action. Conclusions based on a single inhibitor could be cited as “evidence” for a certain pathway.     

Effects of amines on the carotenogenesis in Blakeslea trispora

Six amines profoundly affected carotenogenesis in Blakeslea trispora. When cultures were treated with the amines, namely 4-[β-(diethylamino)-ethoxy]-benzaldehyde, 4-[β-(diethylamino)-ethoxy]-acetophenone hydrochloride, 4-β-(diethylamino)-ethoxy]-benzophenone hydrochloride, triethylamine hydrochloride, α-diethylaminopropiophenone hydrochloride and tributylamine hydrochloride, an increase in the lycopene accumulation was observed. The modes of action of these amines appear to be similar to that of 2-(4-chlorophenylthio)triethylamine hydrochloride (CPTA); however, they difrer in relative effectiveness.     

Isolation and identification of 2-hydroxyplectaniaxanthin from Rhodotorula aurantiaca

A new trihydroxyl carotenoid has been isolated from the yeast Rhodotorula aurantiaca (Saito) Lodder C.B.S. 317 and identified as 2-hydroxyplectaniaxanthin (3′,4′-didehydro,1′,2′-dihydro-β, ψ-caroten-2,1′,2′-triol). Its m.p., partition coefficient, _Rf, extinction coefficient, ms and NMR spectra are reported. Since the hydroxyl group at C-2 of the β-ionone ring is unusual, a possible mechanism for the biosynthesis of this carotenoid has been proposed.     

Effect of CPTA and cycocel on the biosynthesis of carotenoids by Phycomyces blakesleeanus mutants

CPTA and cycocel cause accumulation of lycopene and γ-carotene, simultaneously inhibiting the formation of β-carotene and β-zeacarotene in Phycomyces blakesleeanus mutant strain C115. Phytoene synthesis is enhanced. CPTA is more effective than cycocel. Kinetic studies show that with increasing concentrations of CPTA, lycopene and γ-carotene increase with the concomitant decrease in β-carotene, the total of these three carotenes being almost equal to β-carotene present in the control. When CPTA-treated mycelium is washed free of the chemical and resuspended in phosphate buffer solution containing 2·5% glucose (pH 5·6), β-carotene is formed at the expense of both γ-carotene and lycopene. β-Zeacarotene, which is not present in the mycelium, reappears upon resuspension. These results indicate that CPTA is inhibiting the enzymes causing cyclization both at neurosporene and lycopene levels. Studies on the effect of CPTA on the high lycopene mutant strain C9 reveal that with increasing concentrations of the compound, lycopene increases slightly and both β-carotene and γ-carotene decrease. Phytoene synthesis is stimulated up to a certain level of CPTA and then becomes steady. In the albino mutant strain C5, there is a slight increase in phytoene formation on the addition of CPTA to the medium. No other carotenoid is formed, suggesting that CPTA cannot remove the block caused by genetic mutation and exerts its influence in an already existing biosynthetic pathway.     

磁场对红酵母的生长及类胡萝卜素合成的影响

考察直流电磁场对类胡萝卜素产生前红酵母RG-98的生长及代谢的影响。结果表明,不同的磁场强度、处理时间及处理方式会产生不同的生物效应。将液体种子和发酵培养基一起置于0.10T电磁场处理2h,能使色素的发酵产量提高25％。比较经磁场处理与未经处理的发酵过程,发现磁场处理提高了红酵母对糖的代谢速率,并且在发酵后期促进生物量和色素含量持续地增加。     

Physical separation of the aqueous phase and lipoidal lamellae from multilamellar liposomes: An analytical and preparative procedure

A method for the determination of the urinary melanocyte metabolite 5,6-dihydroxyindole-2-carboxylic acid is described. The catecholic indole is adsorbed onto alumina, chromatographed on a reverse-phase octadecyl silica column, and detected by fluorometry. The sensitivity of the method permits detection of 1 pmol injected.     

Biosynthesis of 1,2-dihydrocarotenoids in Rhodopseudomonas viridis: Experiments with inhibitors

The effects of the inhibitors diphenylamine (DPA), 2-(4-chlorophenylthio) triethylammonium chloride (CPTA) and nicotine on the biosynthesis of 1,2-dihydrocarotenoids by Rhodopseudomonas viridis (Rhodospirillaceae) have been investigated. Small amounts of 1,2-dihydro derivatives of phytoene, phytofluene and ξ-carotene and its unsymmetrical isomer, and 1,2,1′,2′,-tetrahydro derivatives of neurosporene and lycopene were isolated from R. viridis grown in the presence of DPA, although there was virtually no quantitative effect on the levels of the normal main carotenoids, neurosporene and lycopene and their 1,2-dihydro derivatives. Nicotine also had little effect on the overall carotenoid composition, but the formation of 1,2-dihydrocarotenoids was inhibited to some extent by CPTA. The 1,2-dihydro end group may thus be introduced by a hydrogenation reaction similar to the more familiar C-1,2 hydration reaction characteristic of carotenoid biosynthesis in other photo synthetic bacteria.     

Composition and biosynthetic pathways of carotenoids in the astaxanthin-producing green alga Chlorococcum sp.

The composition of the secondary carotenoids in the astaxanthin-producing green alga Chlorococcum sp. was analyzed. Eight types of carotenoids were identified by a variety of spectroscopic techniques. Canthaxanthin, 3-hydroxyechinenone, adonirubin and adonixanthin comprised, respectively, 32%, 23%, 12% and 9% of total carotenoids. The results imply that Chlorococcum sp. synthesized astaxanthin from -carotene through various pathways which are different from other astaxanthin-producing microorganisms.     

玉米营养成分时空动态

研究了玉米营养成分时空动态变化．结果表明,随着玉米生育期的推进,玉米籽粒的总淀粉、粗蛋白和粗脂肪的含量逐渐升高;而茎、叶的粗蛋白、粗脂肪含量逐渐下降,中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素含量逐渐升高．茎、叶粗蛋白含量下降的幅度大于籽粒粗蛋白含量上升幅度．同时,玉米植抹上部叶片的粗蛋白含量高于下部叶片,而中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质索含量低于下部叶片．茎上部粗蛋白含量高于下部,中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素含量低于下部．     

The effect of diphenylamine on carotenogenesis in Phycomyces blakesleeanus

The presence of diphenylamine (DPA) during growth of mutant strains of Phycomyces blakesleeanus caused the expected inhibition of the formation of unsaturated carotenes, and the accumulation of phytoene in all cases. Cell extracts from DPA-grown cultures incubated with [2-¹⁴C]mevalonic acid, also exhibited these effects. Inhibition of in vitro carotenogenesis was similarly shown by extracts from normally-grown mycelia, incubated with DPA. Removal of DPA from mycelia or from cell extracts, resulted in the formation of unsaturated carotenes. The ratio of 15-cis-all-trans-phytoenes from mycelia grown ± DPA was only marginally altered, but, in vitro, the presence of DPA caused a significant increase in the formation of the all-trans isomer in the C5 strain. These results indicate that DPA acts by post-translational regulation of enzymic activities.     

Carotenoid biosynthesis and the evolution of carotenogenesis genes in rust fungi

Diseases caused by rust fungi pose a significant threat to global plant production. Although carotenoid pigments are produced in spores of nearly all rust species, the corresponding biosynthesis pathway(s) have not been investigated. Here, candidate genes for carotenoid biosynthesis in Puccinia graminis f. sp. tritici (Pgt) were identified, cloned and functionally complemented using specifically engineered strains of Escherichia coli. A part of the carotenoid biosynthesis pathway in rust fungi was elucidated, with only two genes, CrtYB and CrtI, catalysing the reactions from geranyl–geranyl diphosphate (GGPP) to γ-carotene. The CrtYB gene encodes a bi-functional lycopene cyclase/phytoene synthase, which catalyses the condensation of two GGPP into phytoene, as well as the cyclisation of the ψ-end of lycopene to form γ-carotene. The CrtI gene encodes a phytoene desaturase that carries out four successive desaturations of phytoene, through the intermediates phytofluene and neurosporene to lycopene. The evolution of carotenoid pigmentation in rust fungi, including Pgt, P. graminis avenae, P. graminis secalis (Pgs), P. graminis lolli, P. striiformis f. sp. tritici, P. striiformis f. sp. pseudohordei, P. striiformis f. sp. hordei, the “scabrum” rust (putative hybrids between Pgt and Pgs), P. triticina, and P. hordei, was investigated by phylogenetic analysis. Both CrtYB and CrtI were found to be closely related among rust fungi, other pathogenic fungi, and some aphids. Our results provide a springboard to increase the understanding of the physiological role(s) of carotenoid pigments in rust fungi, to better understand evolution within the Pucciniales, and to develop robust molecular diagnostics for rust fungi.     

类胡萝卜素生物合成相关基因的克隆及其遗传工程的研究进展

类胡萝卜素具有重要的生物学功能,尤其对人体健康有着更重要的作用,近年来一直是研究的热点。综述了类胡萝卜素生物合成途径及相关基因的分离,以及运用这些基因提高微生物和植物中类胡萝卜素含量的遗传工程研究进展。     

不同品种杜仲叶中有效成分含量差异性研究

对杜仲不同品种叶中有效成分及杜仲胶含量进行了测定,并用方差分析及多重比较方法进行了分析比较,认为品种2主要有效成分绿原酸、京尼平甙酸、桃叶珊瑚甙、总黄酮的含量最高,在1％显著水平上,品种2绿原酸含量与品种3、4、5有显著差异,1、3、4、5品种间没有显著差异,京尼平甙酸和总黄酮含量与品种1、3、4、5间有显著差异,桃叶珊瑚甙含量在品种1、2、3、4、5之间都有显著差异;品种1和品种2的含胶量较高,在1％显著水平上,品种1含胶量与品种3、4、5间差异极显著,品种2与品种3、4、5间差异极显著,这两个结论为药用和胶用型优良品种选择提供了依据。     

红酵母类胡萝卜素高产菌株的筛选及其发酵生理学条件研究

从数株红酵母中选出了1株产类胡萝卜素能力较强的红酵母RY－98（生物量,类胡萝卜素含量和产量分别为19．9g/L,334.8ug/g和6．7mg/L);研究了该菌株产类胡萝卜素的最适营养与环境条件,获得了最佳的发酵生理学条件;葡萄糖40g/L,(NH4)2SO4 10g/L,酵母膏3g/L,蕃茄汁2mL/L,花生油0.5mL/L,接种量30mLL初始pH6.0和通气量（培养基装置040ml/250mL:,在此初步优化的培养条件下,红酵母RY－98经72小时摇瓶发酵其生物量,类胡萝卜素含量和产量分别可达26．8g/L,386.9ug/g和10．4mg/L,依次比初筛中提高了34．7％,15．6％,和55．2％。     

Chloroplast Proteomics and the Compartmentation of Plastidial Isoprenoid Biosynthetic Pathways

Recent advances in the proteomic field have allowed high-throughput experiments to be conducted on chloroplast samples. Many proteomic investigations have focused on either whole chloroplast or sub-plastidial fractions. To date, the Plant Protein Database （PPDB, Sun et al., 2009） presents the most exhaustive chloroplast proteome available online. However, the accurate localization of many proteins that were identified in different sub-plastidial compartments remains hypothetical. Ferro et al. （2009） went a step further into the knowledge of Arabidopsis thaliana chloroplast proteins with regards to their accurate localization within the chloroplast by using a semi-quantitative proteomic approach known as spectral counting. Their proteomic strategy was based on the accurate mass and time tags （AMT） database approach and they built up AT_CHLORO, a comprehensive chloroplast proteome database with sub-plastidial localization and curated information on envelope proteins. Comparing these two extensive databases, we focus here on about 100 enzymes involved in the synthesis of chloroplast-specific isoprenoids. Well known pathways （i.e. compartmentation of the methyl erythritol phosphate biosynthetic pathway, of tetrapyrroles and chlorophyll biosynthesis and breakdown within chloroplasts） validate the spectral counting-based strategy. The same strategy was then used to identify the precise localization of the biosynthesis of carotenoids and prenylquinones within chloroplasts （i.e. in envelope membranes, stroma, and/or thylakoids） that remains unclear until now.     

Creating Carotenoid Diversity in E. coli Cells using Combinatorial and Directed Evolution Strategies

Carotenoids represent a structurally diverse class of pigments with important biological functions and commercial applications. Biosynthesis of carotenoids has been studied on a molecular level for the core pathways and recombinant hosts have been engineered for heterologous carotenoid production. This paper summarizes our efforts on accessing novel carotenoid compounds in engineered E. coli by altering the catalytic activities of enzymes using in vitro evolution, by exploring the catalytic promiscuity of known carotenoid enzymes and by mining for novel enzymes in microbial genome sequences.     

黄山贡菊的挥发油成分

The volatile oil in flowers of Dendranthema morifolium (Ramat) Tzvel. cv. Gongju was extracted with steam distillation, the constituents and contents of volatile oil were analyzed by means of GC-MS-DS techniques. The result shows that the principle constituents of the volatile oil are bicyclo[3.1. 1]hept-2-en-4-ol, 2,6,6-trimethyl-, acetate (39.64%); benzene, 1-( 1,5-dimethyl-4-hexenyl)-4-methyl-,2-heptene (5.24%);n-hexadecanoic acid (4.77%); cis-lanceol (4.73%) ; acetic acid,1,7, 7-trimethyl-bicyclo [2.2.1] hept-2-yl-ester (3.95%); (-) spathulenol (3.38%) ; 2, 4, 6-trimethyl-3-cyclohexene-1-carboxaldehyde(3.22%) ; caryophyllene oxide (2.88%) ; 1,2,3,4, 5,6,7,8-octahydro-1,4-dimethyl-7-(1-methylethenyl)-,azulene (2. 80%); 3-(1, 5-dimethyl-4-hexenyl)-6-methylene, cyclohexaene (2. 50%); decahydro-1, 4a-dimethyl-7-( 1-methylidene)-,1-naphthalenol(2.39%);1,1,2-trimethyl-3,5-bis(1-methylethenyl)-,cyclohexane(2.23% ), etc.     

Regulation of ornithine transcarbamylase in Rhodotorula glutinis

The regulation of ornithine transcarbamylase (OTC) of Rhodotorula glutinis has been studied, by growing the yeasts in different carbon and nitrogen sources and estimating the enzyme level in crude yeasts extracts.The results show a nutritional repression of OTC by arginine, when added to the culture media as carbon, nitrogen or carbon and nitrogen sources. On the other hand ornithine does not exert any effect in the same experimental conditions.     

Biosynthesis of 3-methoxycarbonylpropylglucosinolate in an Erysimum species

Incorporation of DL-2-aminohexanedioic acid, DL-2-amino-5-methoxycarbonyl-pentanoic acid and DL-methionine into 3-methoxycarbonylpropylglucosinolate have been demonstrated using an Erystmum species. The data support the following sequence of biosynthetic reactions: 2-aminohexanedioic acid is methylated by methionine; the resulting 2-amino-5-methoxycarbonyl-pentanoic acid is then converted into the glucosinolate. 2-Amino-5-methoxycarbonyl-pentanoic acid has been tentatively identified as a natural product in the plant.