Biocatalytic synthesis of (R)-(-)-mandelic acid from racemic mandelonitrile by a newly isolated nitrilase-producer Alcaligenes sp. ECU0401

By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp. ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(?)-mandelic acid, with an enantiomeric excess of >99.9%.

Identification and Mutagenesis of a New Isolated Strain Bacillus sp.B26 for Producing （R）-α-Hydroxyphenylacetic Acid

A bacterium strain B26 capable of producing(R)-α-hydroxyphenylacetic acid [(R)-HPA](yield,47.5%;enantiomeric excess,99.1%) from phenylglyoxylic acid(PGA) with high optical purity was isolated and identified as Bacillus sp.B26 by 16S rDNA(ribosomal DNA) sequencing.Phylogenic analysis showed that the strain was most similar to Bacillus sp.enrichment culture clone SYW5(FJ601635.1) and Bacillus cereus strain FM-4(EU794727.1).Efforts were made to further improve HPA-production and PGA-tolerance by UV irradiation and UV-LiCl cooperative mutagenesis.Among viable mutants,B.sp.UV-38 and B.sp.ULi-11 exhibited better productivities than the wild type.Comparisons of HPA production and time course among wild strain and two mutants showed that B.sp.ULi-11 was more competent than B.sp.UV-38.HPA production was increased by 39.1% with B.sp.ULi-11(yield,65.4%) compared to that with B.sp.B26(yield,47.0%) when cultured in fermentation broth(pH 7.2) at 32℃ with an agitation speed of 180 r·min-1 and PGA final concentration of 15 mmol·L-1 for 25 h.

A Novel Method for Production of 3-Hydroxydecanoic Acid by Recombinant Escherichia coli and Pseudomonas putida

3-hydroxydecanoic acid (3HD) is an interesting intermediate for chemical synthesis of many valuable compounds. A novel method to produce 3HD by recombinant bacteria was constructed in Escherichia coli HB101 and Pseudomonas putida GPpl04, respectively. Simultaneous expression of both phaG encoding (R)-3-hydroxydecanoyl-ACP:CoA transacylase and tesB encoding thioesteraseⅡin E. coli HB101 increased 3HD production approximate 1.7-folds compared with the expression of phaG gene alone under identical conditions. In addition, when the tesB gene was introduced into the strain, the polyhydroxyalkanoate synthase negative strain P. putida GPpl04 produced extracellular 3HD. Thus, a novel pathway to produce 3HD by recombinant Pseudomonas was constructed. It was also found that the ratio of carbon source to nitrogen source affected the production of 3HD by recombinant P. putida harboring tesB gene. Nitrogen limitation seemed to promote the extracellular 3HD production.

Asymmetric bioreduction of γ- and δ-keto acids by native carbonyl reductases from Saccharomyces cerevisiae

Optically pure(R)-γ-and(R)-δ-lactones can be prepared by intramolecular cyclization of chiral hydroxy acids/esters reduced asymmetrically from γ-and δ-keto acids/esters using Saccharomyces cerevisiae(S.cerevisiae) as a whole-cell biocatalyst.However,some of the enzymes catalyzing these reactions in S.cerevisiae are still unknown up to date.In this report,two carbonyl reductases,OdCRl and OdCR2,were successfully discovered,and cloned from S.cerevisiae using a genome-mining approach,and overexpressed in Escherichia coli(E.coli).Compared with OdCR1,OdCR2 can reduce 4-oxodecanoic acid and 5-oxodecanoic acid asymmetrically with higher stereoselectivity,generating(R)-γ-decalactone(99% ee) and(R)-δ-decalactone(98% ee) in 85% and 92%yields,respectively.This is the first report of native enzymes from S.cerevisiae for the enzymatic synthesis of chiral γ-and δ-lactones which is of wide uses in food and cosmetic industries.

Enantioselective esterification of(R,S)-2-(4-methylphenyl)propionic acid via Novozym 435:Optimization and application

This paper reports on the resolution of(R,S)-2-(4-methylphenyl)propionic acid(MPPA)enantiomers by enzymatic esterification in organic solvent.Novozym 435(CALB)has the best catalytic performance compared with other lipases.Of the alcohols screened,n-hexanol is the best acyl acceptor and gives the highest enzyme activity and enantioselectivity in n-hexane.Response surface methodology(RSM)was used to evaluate the influence of the factors,such as temperature,enzyme amount,substrate concentration and reaction time on the substrate conversion(c)and enantiomeric excess(ee).The correlation coefficient R2 for enantiomeric excess and the conversion are 0.9827 and 0.9910,respectively,indicating that can accurately predict the experimental results.By simulation and optimization,the optimal conditions were obtained,involving 600 mmol·L^-1 MPPA concentration(0.60 mmol),850 mmol·L^-1 hexanol concentration(0.85 mmol),58 mg enzyme amount,75℃temperature and 4.5 h reaction time,respectively.Under the optimized conditions,the experimental values of conversion and enantiomeric excess were 89.34%and 97.84%,respectively,which are in good agreement with the model predictions.

Synthesis of (R)(E)-3,7-Dimethyl-2-octene-1,8-dioic Acid, a Copulation Released Pheromone Component of Azuki Bean Weevil

Started from 5-hydroxy-2-pentanone, (R)(E)-3,7-dimethyl-2-octene-1,8-dioic acid, callosobruchusic acid, was synthesized via five steps with D-(-)-camphor sultam as the chiral auxiliary. It was of good optical purity and yield.

Study on Bicoordination Chiral Inducement Catalysis of (R)-4-Thiazolidinecarboxylic Acid

The bicoordination chiral inducement catalysis of (R)-4-thiazolidinecarboxylic acid inthe enantioselective borane reduction of prochiral ketones has been studied. The fact that theabsolute configuration of the main product can be changed by simply using different operationmethods was firstly verified. And the reason of bicoordination chiral inducement was discussed.

IMMOBILIZATION OF Saccharomyces Cerevisiae USING POLY(ACRYLAMIDE)GEL FOR ASYMMETRIC SYNTHESIS OF R(-)-MANDELIC ACID

In this paper,the poly(acrylamide)hydrogel used to immobilize saccharomyces cerevisiae for asymmetric synthesis of R(-)-mandelic acid was prepared with free radical ploymerization in deionized water at room temperature under nitrogen atmosphere.The influence of the composition of hydrogel,loading amount of cells and culture conditions on the asymmetric synthesis was investigated.Results show that PAAm hydrogel is a feasible carrier for immobilization of cells which is a potential alternative method to prepare enantiomerically pure R(-)-mandelic acid.

Crystal Structure and Biological Activities of (R)-N′-[2-(4-Methoxy-6-chloro)-pyrimidinyl]-N-[3-methyl-2-(4-chlorophenyl)butyryl]-urea

The title compound （R）-N′-[2-（4-methoxy-6-chloro）-pyrimidyl]-N-[3-methyl-2-（4- chlorophenyl）butyryl]-urea has been synthesized, and its crystal structure and biological behaviors were studied. Crystallographic data： C17H18C12N4O3, Mr = 397.25, monoclinic, space group P21/c, a = 12.331（2）, b = 14.025（3）, c = 23.085（5） A, β = 99.607（4）°, Z = 8, V = 3936.2（13） A3, Dc = 1.341 g/cm^3, F（000） = 1648, R = 0.0718, wR = 0.1585 and/t（MoKα） = 0.353 mm^-1. The preliminary biological tests showed that the title compound has definite insecticidal and fungicidal activities.

Synthesis,Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

Chiral amino acids and their corresponding amino alcohols bearing camphoric backbone were prepared from D-（＋）-camphoric imide and characterized by infrared, elemental analysis, ESI-MS, and NMR measurements. Among them, one intermediate （1S,3R）-3-amino-2,2,3- trimethyl cyclopentane-1-carboxylic acid hydrochloride 3 was structurally elucidated by X-ray diffraction techniques. Versatile intermolecular hydrogen bonding interactions observed in its packing structure result in a two-dimensional framework.

Design, Synthesis, Antifungal Activities and SARs of （R）-2-Aryl-4,5-dihydrothiazole-4-carboxylic Acid Derivatives

Based on the structure of natural product 2-aryl-4,5-dihydrothiazole-4-carboxylic acid, a series of novel （R）-2-aryl-4,5-dihydrothiazole-4-carboxylic acid derivatives were designed and synthesized. Their structures were characterized by ^1H NMR, ^13C NMR and HRMS. The single crystal structure of compound 9b was determined by X-ray diffraction analysis. The antifungal activities were evaluated for the first time. The bioassay results indicated that most compounds exhibited moderate to good antifungal activities. The antifungal activities of compound 13a （against Cercospora arachidicola Hori）, 13d （against Alternaria solani）, and 16e （against Cercospora arachidieola Hori） were 61.9%, 67.3% and 61.9%, respectively, which are higher than those of the commercial fungicides chlorothalonil and carbendazim. Moreover, compound 13d exhibited excellent antifungal activities against 7 kinds of the fungi tested （66.7%, 77.3%, 63.0%, 87.9%, 70.0%, 70.0% and 80.0% at 50 μg/mL）. Therefore, 13d can be used as a new lead structure for the development of antifungal agents.

Resolution of racemic R.S-α-arylethylamine by a new resolving agent (R)thiazolidine-2-thione-4-carboxylic acid

Racemic R.S-α-arylethylamine was resolved by R (-) thiazolidine-2-thione-4-carboxylic acid, a new resolving agent abbreviated as [R (-) TTCA], by which R (-) TTCA.S(-) arylethylamine salts2a-2e, [α] D 20 =-47.24° — 64.40° and optically active R(+)-a-arylethylamines3a – 3e, 74. 54%-94. 45% e, e., were obtained. Optically active S (-) -α-arylethylamines4a-4e, 72.84%-90.36% e.e., were obtained by the decomposition of2a-2e in basic solutions. The influence of substitutive group of the benzene ring on the basicity of the amino group was studied by semiempirical PM3 method. The structures of the R (-) TTCA.S (-) -α-phenylethylamine salt (2a(R-S) configuration) and R (-) TTCA-R(+)-a-phenylethylamine salt (2a(R-R) configuration) have been established by means of X-ray diffraction. They crystallize in a monoclinic system. Space group isP21. The cell constants of2a(R-S) configuration were obtained as follows: α = 1.387 8(2), b = 0.664 05(101,c = 1.580 O(2) nm; β = 90.844(10)° Z = 4; those obtained for2a(R-R) configuration were α = 1.080 6(2),b = 0.584 80(12),c = 1.2188(2) nm, β= 110.38(3)dg, V = 0.7220nm3,Z = 2. There are intermolecular hydrogen bonds in the crystals of the two kinds of configurations of the amine salt. The hydrogen bond number in the unit cell of R (-) TTCA.S (-)-α-phenylethylamine salt is twice as much as that of R (-) TTCA.R(+)-a-phenylethylamine salt.

Biosynthesis of(R)-2-hydroxy-3-phenylpropionic acid using whole recombinant Escherichia coli cells in an aqueous/n-octane biphasic system

（R）-2-hydroxy-3-phenylpropionic acid （PIP,） is an ideal antimicrobial compound with broad-spectrum activity against a wide range of Gram-positive bacteria, some Gram-negative bacteria, and fungi. We studied the bioconversion of phenylpyruvate （PPA） to PLA using whole recombinant Escherichia coli cells in a series of buffer/organic solvent systems. Octane was found to be the best organic solvent. The optimum volume ratio of the water phase to the n-octane phase, conversion temperature, substrate concentration, and cell concentration were 6：4, 40 ℃, 12.5 g/L, and 30 g/L wet cells, respectively. Under the optimized conditions, the average PLA productivity in the aqueous/ n-octane system was 30.69% higher than that in the aqueous system, and 32.31 g/L PLA was obtained with the use of a stirred reactor （2-L scale）. Taken together, our findings indicated that PLA biosynthesis was more efficient in an aqueous/n-octane biphasic system than in a monophasic aqueous system. The proposed biphasic system is an effective strategy for enhancing PLA yield and the biosynthesis of its analogues.

Crystal Structure of Isoquinoline Derivatives

The chiral compound 5H-imidazol[2,3-b]isoquinoline-l-ethanol-5-one-1,2, 3, 10b-tetrahydro- β（S）-phenyl-3（S）-phenyl was synthesized from the direct condensation of 2- cyanophenyacetonitrile with optically active （S）-（＋）-2-phenylglycinol in chlorobenzene under dry, anaerobic conditions. ZnCl2 was used as a Lewis acid catalyst in this reaction, and the structure of this compound was determined by X-ray diffraction, NMR, MS and IR. Crystal data of the title compound： C25H22N2O2, Mr = 382.45, P 21 21 21, a = 5.341（5）, b = 16.735（5）, c = 22.129（5） A, γ = 90°, V = 1978（2）A^3, Z = 4, Dc = 1.284 g/cm^3, the final R = 0.0321 for 2269 observed reflections with I 〉 2 σ（I） and Rw = 0.0771 for all data.

Copper-mediated chemodynamic therapy with ultra-low copper consumption by doping cupric ion on cross-linked(R)-(+)-lipoic acid nanoparticles

Cu-mediated chemodynamic therapy(CDT)has attracted prominent attention owing to its advantages of pH independence and high efficiency comparing to Fe-mediated CDT,while the application of Cu-based CDT agents was impeded due to the high copper consumption caused by the metabolism loss of copper and the resultant potential toxicity.Herein,we developed a new copper-mediated CDT agent with extremely low Cu usage by anchoring copper on cross-linked lipoic acid nanoparticles(Cu@cLAs).After endocytosis into tumor cells,the Cu@cLAs were dissociated into LA and dihydrolipoic acid(DHLA)(reduced form of LA)and released Cu^(2+)and Cu+(oxidized form of Cu^(2+)),the two redox couples recycled each other in cells to achieve the efficient killing of cancer cells by delaying metabolic loss and increasing the ROS level of tumor cells.The self-recycling was confirmed in cells by the sustained high Cu/DHLA content and persistent ROS generation process.The antitumor study based on the MCF-7/R nude mice gave the Cu@cLAs a tumor inhibitory rate up to 77.9%at the copper of 0.05 mg kg^(−1),the first dosage reported so far lower than that of normal serum copper(0.83±0.21 mg kg^(−1)).This work provides not only a new promising clinical strategy for the copper excessive use in copper-mediated CDT,but also gives a clue for other metal mediated disease therapies with the high metal consumption.

基于NMR指导的六神曲成分研究

目的研究六神曲的化学成分。方法运用各种色谱技术分离六神曲的化学成分,并利用理化性质和波谱技术鉴定其结构。结果从六神曲中分离得到11个成分,分别鉴定为5-二十五烷基间苯二酚(1)、5-十七烷基间苯二酚(2)、5-二十一烷基间苯二酚(3)、5-二十三烷基间苯二酚(4)、(9S,10E,12Z)-9-hydroxy-10,12-octadecadienoic acid(5)、trans-4-hydroxy-2-nonenoic acid(6)、9,10,11-trihydroxy-11(E)-octadecenoic acid(7)、(9S,12R,13S)-9,12,13-trihydroxy-10(E)-octadecenoic acid(8)、(9S,12S,13S)-9,12,13-trihydroxy-10(E)-octadecenoic acid(9)、(9S,12S,13S)-9,12,13-trihydroxy-10(E)-octadecenoic acid methyl ester(10)、9,12(Z)-octadecadienoic acid methyl ester(11)。结论化合物1~11均为首次从六神曲中分离得到。抗炎活性研究显示,六神曲氯仿提取物和化合物8均显示出良好的抗炎活性。

来自普哥滨珊瑚的一株Talaromyces sp.真菌的活性次生代谢产物

利用硅胶柱层析、制备型HPLC和重结晶等手段从普哥滨珊瑚分离的一株Talaromycessp.真菌C21-1中筛选得到2个活性化合物,运用核磁共振、质谱和圆二色谱等技术鉴定这两个化合物分别为(R)-(-)-hydroxysydonic acid(1)和homodimeric WIN 64821(2),补充完善了化合物2的核磁共振信号归属,并对化合物进行抗菌活性和乙酰胆碱酯酶抑制活性的测定,发现化合物1对白色假丝酵母Canidia albicans和耐甲氧基青霉素的金黄色葡萄球菌Methicillin-resistantStaphylococcusaureus(MRSA)具有一定的抑制作用,其最低抑菌浓度(MIC)分别为0.075mmol/L和0.2mmol/L,对副溶血弧菌Vibrio parahemolyticus的抑制活性较弱,在0.2mmol/L浓度下的抑制率为17%;化合物2最大浓度0.2mmol/L条件下对这3种菌均没有明显的抑制效果。化合物2表现出剂量依赖的乙酰胆碱酯酶抑制活性,0.5mmol/L时抑制率达到35.1%。