Lignans from stems and leaves of Cephalotaxus fortunei / 中草药

Objective: To study chemical constituents of Cephalotaxus fortunei. Methods: The chemical constituents were separated and purified by preparative thin-layer chromatography, silica gel, ODS, HP20 macroporous resin and Sephadex LH-20 gel column chromatography, and semi-preparative HPLC. Their structures were determined by NMR and ESI-MS spectroscopic techniques. Results: Seventeen lignans were isolated from the ethanol extracts of C. fortunei and their structures were identified as shonanin (1), arctigenin (2), α-conidendrin (3), matairesinol (4), nortrachelogenin (5), epinortrachelogenin (6), (7'S)- hydroxymatairesinol (7), (7'R)-hydroxymatairesanol (8), (7'S)-hydroxyarctigenin (9), secoisolariciresinol (10), 4,4'-di-O-methylcephafortin A (11), 5-(3″,4″-dimethoxyphenyl)-3-hydroxy-3-(4'-hydroxy-3'-methoxybenzyl)-4-hydroxymethyl-dihydrofuran-2-one (12), cephafortin B (13), dihydrodehydrodiconiferyl alcohol (14), 7R,8S-4,7,9,9'-tetrahydroxy-3,3'-dimethoxy-8-O-4'-neolignan (15), 7R,8R-4,7,9,9'- tetrahydroxy-3,3'-dimethoxy-8-O-4'-neolignan (16), and threo-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (17). Conclusion: Compounds 3, 6, 10 and 17 were isolated from genus Cephalotaxus for the first time, and compounds 4, 5, 7-9, 12 and 14 were isolated from C. fortunei for the first time.

Small interfering RNA for cancer treatment: overcoming hurdles in delivery

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

Bottlenecks and modification strategies of 1,3-propanediol biosynthesis from glycerol / 生物工程学报

Crude glycerol is the main by-product of biodiesel production. A few microorganisms can transfer crude glycerol to 1,3-propanediol (1,3-PD) that is an important chemical material. There exist many limitations such as substrate inhibition, product inhibition when wild strains are used in 1,3-PD biosynthesis. In this review, based on the microbial transformation of 1,3-propanediol from glycerol and its limitations, some strategies using genetic engineering such as knockout or gene overexpression were summarized. The latest research progresses in biosynthesis of 1,3-propanediol from glycerol by genetically engineered strains are discussed.

On-line monitoring of biomass in 1,3-propanediol fermentation by Fourier-transformed near-infrared spectra analysis / 生物工程学报

Biomass is an important parameter reflecting the fermentation dynamics. Real-time monitoring of biomass can be used to control and optimize a fermentation process. To overcome the deficiencies of measurement delay and manual errors from offline measurement, we designed an experimental platform for online monitoring the biomass during a 1,3-propanediol fermentation process, based on using the fourier-transformed near-infrared (FT-NIR) spectra analysis. By pre-processing the real-time sampled spectra and analyzing the sensitive spectra bands, a partial least-squares algorithm was proposed to establish a dynamic prediction model for the biomass change during a 1,3-propanediol fermentation process. The fermentation processes with substrate glycerol concentrations of 60 g/L and 40 g/L were used as the external validation experiments. The root mean square error of prediction (RMSEP) obtained by analyzing experimental data was 0.341 6 and 0.274 3, respectively. These results showed that the established model gave good prediction and could be effectively used for on-line monitoring the biomass during a 1,3-propanediol fermentation process.

Computational analysis of 1,3-propanediol operon transcriptional regulators: insights into Clostridium sp. glycerol metabolism regulation / Análisis computacional de los reguladores transcripcionales del operón 1,3-propanodiol: indicios sobre la regulación del metabolismo del glicerol en Clostridium sp / Análise computacional dos reguladores transcricionais do operon do 1,3-Propanodiol: Panorama da regulacáo do metabolismo do glicerol no Clostridium sp

We designed a strategy for the sequencing and bioinformatical characterization of the 1,3-propanediol operon regulator genes from the Colombian Clostridium sp. strain IBUN13A, which is taxonomically related to Clostridium butyricum. Three genes are proposed to be involved in the operon's transcriptional activity, the dhaS and dhaA genes through a two-component system and the third gene named dhaY, which encodes a putative transcriptional regulator similar to the domains of the dhaS/A system. Phylogenetic analyses indicated that the predicted proteins had a modular structure consisting of domains homologous to different signal transduction systems, but had significant differences concerning their conserved residues, pointing to the possibility that they constitute ancestral domains. In accordance with the prediction of functions, we propose a mechanism of regulation of the proteins studied of the 1,3-propanediol operon of the native strain, as a response to the presence of glycerol in the medium, which provides valuable information on the overall regulation of the glycerol metabolism in Clostridium sp.

Se diseñó una estrategia de amplificación, secuenciación y caracterización bioinformática de los genes reguladores del operón 1,3-propanediol (1,3-PD) de la cepa nativa colombiana Clostridium sp. IBUN 13A, relacionada taxonómicamente con Clostridium butyricum. Se identificaron tres genes que pueden estar involucrados en la regulación transcripcional de dicho operón: los genes dhaS y dhaA -a través de un sistema de transducción de señales de dos componentes-y un tercer gen que se denominó dhaY, que codifica para un regulador transcripcional putativo, similar a los dominios presentes en las proteínas del sistema DhaS/A. Los análisis filogenéticos indican que las proteínas predichas presentan una estructura modular con dominios homólogos a diferentes sistemas de transducción de señales, pero muestran diferencias importantes en los residuos conservados, lo que sugiere que podrían ser estos los dominios ancestrales. La predicción de funciones postula un mecanismo de regulación de las proteínas estudiadas sobre el promotor del operón 1,3-PD de la cepa nativa como respuesta a la presencia de glicerol en el medio, lo cual aporta información importante sobre la regulación global del metabolismo del glicerol en Clostridium sp.

Nesta pesquisa foi feita uma estratégia para a amplificacäo, sequenciamento e caracterizacäo bioinformática dos genes reguladores do operon 1,3 propanodiol (1,3-PD) da cepa colombiana Clostridium sp. IBUN 13A, relacionada taxonomicamente com o Clostridium butyricum. Tèm sido identificados tres genes que podem estar envolvidos na regulacáo transcricional do operon. Os genes dhaS e dhaA por meio de um sistema de dois componentes e o terceiro gene nomeado de dhaY, que codifica para um regulador transcridonal putativo, parecido com os dominios presentes nas proteínas do sistema DhaS/A. A análise filogenètica mostra que estas proteínas apresentam uma estrutura modular com dominios homólogos a diferentes sistemas de traducáo de sinais, mas pressupöem diferencas importantes nos residuos conservados, indicando provavelmente que possam constituir os dominios ancestrais. De acordo com a predicáo de funcöes, é postulado um mecanismo de regulacáo do sistema DhaS/A, DhaY sobre o promotor do operon 1,3-DP da cepa nativa, como resposta à presenca de glicerol no meio, aportando informacöes importantes da regulacáo global do metabolismo do glicerol no Clostridium sp.

The effect of high concentrations of glycerol on the growth, metabolism and adaptation capacity of Clostridium butyricum DSP1

Background The production of biofuels from renewable energy sources is one of the most important issues in biotechnology today. The process is known to generate various by-products, for example glycerol that is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol. The main drawback of that technology is the use of high concentrations of glycerol, which inhibits the growth of bacterial cells. Results This study investigated the impact of crude glycerol on Clostridium butyricum DSP1 and its ability to adapt to an environment of high osmotic pressure. It was found that a crude glycerol concentration of up to 70 g/L did not have an inhibitory effect on C. butyricum DSP1. Adaptation procedures involving the passage of metabolically active biomass from a fermentation medium with a lower concentration of crude glycerol to one with a greater substrate concentration allowed breaking the barrier of high osmotic pressure (150 g/L crude glycerol) and receiving a 1,3-PD concentration of 74 g/L in a batch culture operation. The work looked into intracellular modifications shown by proteomic profiling in order to explain the mechanisms underlying the response and adaptation of bacterial cells exposed to unfavorable environmental conditions. Conclusions This study of the effect of glycerol on the growth and metabolism of C. butyricum DSP1 demonstrated that the maximum substrate concentrations that do not inhibit the metabolic activity of bacterial cells are 90 g/L and 70 g/L for pure and crude glycerol, respectively.

Biotechnological potential of Clostridium butyricum bacteria

In response to demand from industry for microorganisms with auspicious biotechnological potential, a worldwide interest has developed in bacteria and fungi isolation. Microorganisms of interesting metabolic properties include non-pathogenic bacteria of the genus Clostridium, particularly C. acetobutylicum, C. butyricum and C. pasteurianum. A well-known property of C. butyricum is their ability to produce butyric acid, as well as effectively convert glycerol to 1,3-propanediol (38.2 g/L). A conversion rate of 0.66 mol 1,3-propanediol/mol of glycerol has been obtained. Results of the studies described in the present paper broaden our knowledge of characteristic features of C. butyricum specific isolates in terms of their phylogenetic affiliation, fermentation capacity and antibacterial properties.

Chemical constituents in n-butanol extract from pine needles of Cedrus deodara / 中草药

Objective: To investigate the chemical constituents in the n-butanol extract of pine needles of Cedrus deodara. Methods: Chemical constituents were separated and purified by silica gel and Sephadex LH-20 chromatography column. The structures were elucidated on the basis of physicochemical properties and spectral data (1H-NMR, 13C-NMR, and DEPT). Results: The compounds were identified as 1-(4'-hydroxy-3'-methoxyphenyl)-2-[4″-(3-hydroxypropyl)-2″-methoxyphenoxy]-1, 3-propanediol (1), (7S, 8R)-9, 9'-dihydroxy-3, 3'-dimethoxy-7, 8-dihydro-benzofuran-1'-propanol base neolignan-4-O-β-D-glucoside (2), (7R, 8R)-3', 9, 9'- trihydroxy-3-methoxy-7, 8-dihydro-benzofuran-1'-propanol base neolignans-9-O-α-L-rhamnoside (3), (6R, 9R)-6-hydroxy-3-oxo-α- ionol-9-O-β-D-glucopyranoside (4), (6R, 9R)-3-oxo-α-ionol-9-O-β-D-glucopyranoside (5), shikimic acid butyl ester (6), quinic acid butyl ester (7), (6S, 9R)-6-hydroxy-3-oxo-α-ionol-9-O-β-D-glucopyranoside (8), 5-p-trans-coumaroylguinic acid (9), and (E)-1-O-p- coumaroyl-α-D-glucopyranoside (10). Conclusion: Compounds 1-7 are isolated from C. Trew for the first time.

Enhance 1, 3-propanediol production from crude glycerol in batch and fed-batch fermentation with two-phase pH-controlled strategy

The batch fermentation of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae SU6 at different crude glycerol concentration (40-100 g l-1), pH (6.5-7.5) and temperature (31-40ºC) combined with two-phase pH-controlled strategy was investigated. Effect of feeding rate (0.10-0.15 L h-1) was studied in fed-batch fermentation. In batch fermentation, the optimal condition was 60 g l-1 crude glycerol, pH control at 6.5 and cultivation temperature at 37ºC. The maximum 1,3-PD of 20 g l-1, the yield of 0.34 g 1,3-PD g-1 glycerol consumed and the productivity of 1.25 g l-1 h-1 were achieved at 16 hrs cultivation. The by-products were acetic acid and succinic acid at 2.7 and 1.1 g l-1, respectively. Two-phase pH-controlled strategy gave better results (24.95 g l-1 1,3-PD and 1.78 g l-1 h-1 productivity) than constant pH-controlled strategy (20 g l-1 and 1.25 g l-1 h-1, respectively) at 16 hrs incubation. In fed-batch fermentation, the maximum 1,3-PD of 45.35 g l-1 was achieved at constant feeding rate of 0.1 L h-1. The yield and productivity were 0.44 g g-1 and 1.94 g l-1 h-1, respectively. The fed-batch fermentation with constant feeding at 0.1 L h-1 with two-phase pH-controlled strategy gave 2.2 folds higher 1,3 PD concentration than the batch fermentation with two-phase pH-controlled strategy. This demonstrated the great impact of combination of pH control and feeding strategies in fed-batch fermentation on enhancing 1,3-propanediol production.

Codon optimization of 1, 3-propanediol oxidoreductase expression in escherichia coli and enzymatic properties

The gene dhaT from Klebsiella pneumoniae encoding 1,3-propanediol oxidoreductase (PDOR) was de novo synthesized by splicing overlap extension polymerase chain reaction (SOE-PCR) primarily according to Escherichia coli’s codon usage, as well as mRNA secondary structure. After optimization, Codon Adaptation Index (CAI) value was improved from 0.75 to 0.83, meanwhile energy of mRNA secondary structure was increased from -400.1 to -86.8 kcal/mol. This synthetic DNA was under control by phage T7 promoter in the expression vector pET-15b and transformed into the E. coli BL21 (DE3) strain. Inducers such as isopropyl beta-D-thiogalactoside (IPTG) and lactose were compared by activity at different inducing time. The activity of PDOR after codon optimized was 385.4 +/- 3.6 U/mL, which was almost 5-fold higher than wild type (82.3 +/- 1.5 U/ml) under the flask culture at 25ºC for 10 hrs. Then his-tagged enzyme was separated by using Ni-IDA column. The favorite environment for enzyme activity was at 5°C and pH 10.0, PDOR showed a certainly stability in potassium carbonate buffer for 2 hrs at diverse temperatures, enzyme activity was significantly improved by Mn2+.

Analysing the dhaT gene in Colombian Clostridium sp. (Clostridia) 1,3-propanediol-producing strains / Análisis del gen dhaT en cepas Colombianas de Clostridium sp. (Clostridia) productoras de 1,3-propanodiol / Análise do gene dhaT em cepas colombianas de Clostridium sp. (Clostridia), produtoras de 1,3-propanodiol

Objective: to analyze the dhaT gene, one of the genes responsible for the 1,3-propanediol (1,3-PD) production, in two native Clostridium strains. Materials and methods: The dhaT gene was amplified by Polimerase Chain Reaction with specific primers designed from Clostridium butyricum VPI1718 operon. Bioinformatics tools like BLASTN, ORF finder, BLASTP and ClustalW were used to determine the identity of the sequence and to assign a function. Results: DNA amplification products were obtained from Colombian Clostridium sp. native strains (IBUN 13A and IBUN 158B) and the Clostridium butyricum DSM 2478 strain, which were sequenced. According to the bioinformatics analysis of the above sequences, a high degree of similarity was found with the dhaT gene of different bacterial species. The highest percentage of identity was obtained with the Clostridium butyricum VPI 1718 strain. Conclusion: knowledge of the physical structure of the 1,3-PD operon in native strains opens the way for developing genetic and metabolic engineering strategies for improving processes productivity.

Objetivo: Analizar el gen dhaT, uno de los responsables de la producción de 1,3-propanodiol (1,3-PD), en dos cepas nativas de Clostridium. Materiales y métodos: El gen dhaT fue amplificado por Reacción en Cadena de la Polimerasa, por medio de cebadores específicos diseñados a partir del operon de Clostridium butyricum VPI1718. Herramientas bioinformáticas como BLASTN, ORF finder, BLASTP y ClustalW se usaron para determinar la identidad de la secuencia y asignarle una función. Resultados: Se obtuvieron productos de amplificación de DNA a partir de cepas nativas Colombianas de Clostridium sp. (IBUN 13A y IBUN 158B) y de la cepa Clostridium butyricum DSM 2478, que posteriormente fueron secuenciados. De acuerdo a los análisis bioinformáticos de las secuencias mencionadas, se encontró un alto grado de similitud con el gen dhaT de diferentes especies bacterianas. El más alto porcentaje de identidad se obtuvo con la cepa Clostridium butyricum VPI 1718. Conclusión: El conocimiento de la estructura física del operón 1,3-PD en cepas nativas, abre las puertas al desarrollo de estrategias genéticas y de ingeniería metabólica para mejorar la productividad del proceso.

Objetivo: Analisar o gene dhaT, um dos responsáveis pela produção de 1,3-propanodiol (1,3-PD) em duas cepas nativas de Clostridium. Materiais e métodos: O gene dhaT foi amplificado por Reação em Cadeia da Polimerase, usando cevadores específicos sintetizados a partir do operon de Clostridium butyricum VPI1718. Ferramentas de bioinformática, tais como BLASTN, ORF finder, BLASTP e ClustalW foram utilizadas para determinar a identidade da seqüência e atribuir-lhe uma função. Resultados: Obtiveram-se produtos de amplificação do ADN a partir das cepas nativas colombianas de Clostridium sp. (IBUN 13A e IBUN 158B) e da cepa Clostridium butyricum DSM 2478, que foram posteriormente seqüenciados. Segundo a análise bioinformática das seqüências acima mencionadas, encontrou-se um elevado grau de similaridade com o gene dhaT de diferentes espécies bacterianas. A maior porcentagem de identidade foi obtida com a cepa Clostridium butyricum VPI 1718. Conclusão: O conhecimento da estrutura física do operon 1,3-PD em cepas nativas, abre as portas ao desenvolvimento de estratégias de genética e engenharia metabólica para melhorar a produtividade do processo.

Genetic Engineering Reconstruction of Klebsiella pneumoniae Producing 1,3-propanediol by the Gene yqhD Encoding 1,3-propanediol Oxidoreductase Isoenzyme / 中国生物工程杂志

In the reductive branch, glycerol is first dehydrated to 3-hydroxypropionaldehyde that is then reduced to 1,3-PD under the consumption of reducing power (NADH). If over-expression of the gene dhaB encoding glycerol dehydrase is achieved,the reducing power will be scarce and 3-hydroxypropionaldehyde will be accumulated,which is disadvantage to produce 1,3-propanediol.The structure gene yqhD from E.coli encoding 1,3-propanediol oxidoreductase isoenzyme[under the consumption of reducing power (NADPH)]and the gene dhaB encoding glycerol dehydrase from Klebsiella pneumoniae was amplified using PCR method.The two gene were transferred into expression vector pEtac to construct a novel recombinant Klebsiella pneumoniae (pEtac-dhaB-tac-yqhD).Over-expression of yqhD and dhaB in Klebsiella pneumoniae was achieved with pEtac-dhaB-tac-yqhD.The fermentation result on aerobic conversion showed the increase of 20% of 1,3-propanediol yield by Klebsiella pneumoniae(pEtac-dhaB-tac-yqhD) was obtained compared with Klebsiella pneumoniae.The main by-products,acetic acid and butanediol decreased estrogen receptors 30% obviously.

Effect on the Synthesis of 1,3 propanediol of Organic acids in the Two-stage Fermentation / 中国生物工程杂志

Effect of organic acids on the synthesis of 1,3 propanediol was studied.The adsorption of organic acids from glycerol fermentation liquor by ion-exchange resins was investigated.The results showed that organic acid and 1,3 propanediol production was in negative relationship.The static adsorption showed that ion-exchange resin 005 had the best adsorption abilities of the organic acids in the glycerol fermentation liquor.It was showed that the yield of 1,3propanediol increased by 166% after the extraction of organic acids from glycerol fermentation liquor and the convertion rate increased by 34%.

Cloning, Sequence Analysis and Expression of dhaT Gene from Citrobacter freundii and Purification and Property of Corresponding Recombinant Enzyme / 中国生物工程杂志

1,3-propanediol (1,3-PD) is an important material for chemical industry, therefore, there is much interest in the production of 1,3-PD. The gene dhaT encoding 1, 3-propanediol dehydrogenase ( PDOR) of Citrobacter freundii was amplified by PCR. Sequence analysis of the similarity at the nucleotide and amino acid level between the gene encoding C. freundii PDOR and that of C. freundii ( U09771 ) were 78% and 90% , respectively. The recombinant plasmid pSE-dhaT was constructed by inserting dhaT gene into expression vector pSE380 and then transformed E. coli JM109. The recombinant strain was induced by IPTG to express dhaT. Further more the recombinant enzyme was purifed from recombinant E. coli by Ni-nitrilotriacetate affinity chromatography followed by Sephacral S-300 gel filtration. A single obvious protein about 42kDa could be obtained by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis of recombinant enzyme. The purified enzyme was used to determined enzyme property on the substrate of propionaldehyde and 1, 3-PD. The optimal temperature and optimal pH of the purified enzyme were 37℃, 8.0 for reduction and 25℃, 10. 5 for oxidation, respectively; and the kinetic property of PDOR about Km and V max were 10. 05mmol/L, 37. 27?mol/min/mg for propionaldehyde and 1. 28mmol/L, 25. 55?mol/min/mg for 1,3-PD, respectively; The deduced dhaT gene product (388 amino acids) showed a specific reduction activity of 49. 50U/mg and oxidation activity of 79. 92U/ mg. There also have a putative iron-binding motif ( G-XX-H-X-X-A-H-X-X-G-X-X-X-X-X-P-H-G) as a fingerprint pattern in the recombinant enzyme, the motif is fully conserved among these 1, 3-propanediol dehydrogenase. It is beneficial to the researches of high producing 1, 3-propanediol by gene engineering strain.

Flocculation of Fermented Broth with 1,3 -Propanediol / 微生物学通报

Flocculation of fermented broth with 1,3 -propanediol using component B of natural clarifier-Ⅱ was studied. Firstly, single factor tests and orthogonal tests were carried out. The results showed the main factors which influenced the flocculation and the optimal conditions were: pH6.0, flocculant B 0.01g/L , NaCl 0g/L, and the FR was 95.97% . The following results by filtration experiments, compared with the sample without pretreatment, indicated that the filtration speed of the flocculated sample was improved dramatically, and the weights of net and dry filter cakes were increased by 41.13% and 51.88% , respectively. Electrodialysis experiments showed that flocculation could accelerate desalting process, and could take the place of centrifugal pretreatment when it combined with the filtration.