Exploration of Water-Soluble Natural AIEgens Boosting Label-Free Turn-on Fluorescent Sensing in a DNA Hydrogel.

Various aggregation-induced emission luminogens (AIEgens) have been developed and applied in different areas in recent years. However, AIEgens generally can aggregate and emit strong fluorescence in aqueous solution even containing DNA and other biomacromolecules because of poor water solubility, restricting their application in biosensing and bioimaging in aqueous solution. Moreover, the great majority of AIEgens commonly suffer from complex organic synthesis, environmental damage, and biological toxicity. In this work, jatrorrhizine (Jat), an isoquinoline alkaloid from Chinese herbs, was found to be a natural water-soluble AIEgen that has not been previously reported. Jat's photometric characteristics and single-crystal structure demonstrated that the restriction of intramolecular motion and twisted intramolecular charge transfer were responsible for its AIE phenomenon. Due to the good water solubility and AIE character of Jat, it did not emit fluorescence in the aqueous solution containing DNA and polymers until the formation of the DNA hydrogel. Therefore, a DNA hydrogel fluorescence biosensor was designed by using the target (miRNA) as a catalyst to trigger the entropy-driven circuit of DNA, realizing the ultrasensitive and label-free detection of miRNA with an ultralow limit of detection (0.049 fM, S/N = 3). This biosensing strategy also has excellent stability and acceptable reliability for real sample assay. The results not only indicated the excellent sensing performance of Jat as AIE probes in aqueous solution but also demonstrated the promising application potential of water-soluble natural AIEgens.

MAX transcriptionally enhances PD-L1 to inhibit CD8+ T cell-mediated killing of lung adenocarcinoma cells.

Immune checkpoint blockade (ICB) therapies, such as monoclonal antibodies against the PD-1/PD-L1 immune checkpoint pathway, have been a major breakthrough in the treatment of lung cancer especially lung adenocarcinoma (LUAD), but their effectiveness is limited. High expression of PD-L1 in tumor cells is one of the key reasons evading immune surveillance, yet the mechanisms that regulate PD-L1 expression are not fully understood. By analyzing the chromatin immunoprecipitation sequencing data of MYC-associated X-factor (MAX) based on lung cancer cell lines, we found that the transcriptional regulator MAX is able to bind to the promoter region of the PD-L1 gene. Further, we performed several molecular biology experiments to determine that MAX promotes PD-L1 transcription in LUAD cells, which in turn assists LUAD cells to evade killing by CD8+ T cells, an effect that can be reversed by anti-PD-L1 antibody. In LUAD, the expression of MAX is positively correlated with PD-L1 and the infiltration of CD8+ T cells. Importantly, we further identified that high expression of the MAX/PD-L1 axis is associated with poor overall survival and fist progression of patients with LUAD. Thus, this study sheds light on the mechanism by which MAX inhibits CD8+ T cell-mediated killing of LUAD cells by activating PD-L1 transcription, and MAX may serve as a potential combinatorial target for ICB therapies that block the PD-1/PD-L1 pathway in LUAD.

A Novel Prognostic Nomogram for Gallbladder Cancer after Surgical Resection: A Single-Center Experience.

BACKGROUND: Gallbladder cancer (GBC), which accounts for more than 80% of biliary tract malignancies, has a poor prognosis with an overall 5-year survival less than 10%. The study aimed to identify risk factors and develop a predictive model for GBC following surgical resection. METHODS: 98 GBC patients who underwent surgical resection from Guangdong Provincial People's Hospital were enrolled in the study. Cox-regression analysis was performed to identify significant prognostic factors. A nomogram was constructed and Harrell's concordance index, calibration plot, and decision cure analysis were used to evaluate the discrimination and calibration of the nomogram. RESULTS: Liver resection, tumor size, perineural invasion, surgical margin, and liver invasion were identified as independent risk factors for overall survival (OS) in GBC patients who underwent surgical resection. Based on the selected risk factors, a novel nomogram was constructed. The C-index of the nomogram was 0.777, which was higher than the American Joint Committee on Cancer (AJCC) staging system (0.724) and Nevin staging system (0.659). Decision cure analysis revealed that the nomogram had a better net benefit and the calibration curves for the 1-, 3-, and 5-year survival probabilities were also well matched with the actual survival rates. Lastly, high-risk GBC were stratified based on the scores of the nomogram and we found high-risk GBC were associated with both worse OS and disease-free survival (DFS). CONCLUSION: We developed a nomogram showing a better predictive capacity for patients' survival of resected GBC than the AJCC staging systems. The established model may help to stratify high-risk GBC and facilitate decision-making in the clinic.

Prognostic values and immune suppression of the S100A family in pancreatic cancer.

S100 calcium-binding protein A (S100A) family members regulate multiple biological functions related to pancreatic cancer (PC) progression and metastasis. However, the prognostic and oncologic values of S100A family have not been systematically investigated in PC. In the present study, the mRNA expression and potential functions of S100A family were investigated by bioinformatic analysis. Our results demonstrated that overexpression of S100A2, S100A6, S100A10, S100A11, S100A14 and S100A16 was significantly associated with higher T stage, advanced histologic grade and worse prognosis in PC. Besides, one CpG of S100A2, three CpG of S100A6, four CpG of S100A10, four CpG of S100A11, two CpG of S100A14 and five CpG of S100A16 were negatively associated with corresponding S100A family members expression and positively associated with overall survival (OS). The signature based on four CpGs showed good prediction ability of OS. Besides, S100A2 overexpression took part in the regulation of mitotic cell cycle, ECM-receptor interaction and HIF-1α transcription factor network. Overexpression of S100A6, S100A10, S100A11, S100A14 and S100A16 may impair the infiltration and cytolytic activity of CD8+ T cells through focal adhesion-Ras-stimulating signalling pathway in PC. Overall, this study explores the multiple prognostic values and oncologic functions of the S100A family in PC.

Freestanding Needle Flower Structure CuCo2S4 on Carbon Cloth for Flexible High Energy Supercapacitors With the Gel Electrolyte.

A facile hydrothermal approach was adopted to the direct synthesis of bimetallic sulfide (CuCo2S4) on carbon cloth (CC) without binders for the supercapacitor's electrodes. A possible formation mechanism was proposed. The prepared bimetallic electrode exhibited a high specific capacitance (Csp) of 1,312 F·g-1 at 1 A·g-1, and an excellent capacitance retention of 94% at 5 A·g-1 over 5,000 cycles. In addition, the asymmetric supercapacitor (CuCo2S4/CC//AC/CC) exhibited energy density (42.9 wh·kg-1 at 0.8 kW·kg-1) and outstanding cycle performance (80% initial capacity retention after 5,000 cycles at 10 A·g-1). It should be noted that the electrochemical performance of a supercapacitor device is quite stable at different bending angles. Two charged devices in series can light 28 red-colored LEDs (2.0 V) for 5 min. All of this serves to indicate the potentially high application value of CuCo2S4.

A direct-write method for preparing a bimetal sulfide/graphene composite as a free-standing electrode for high-performance microsupercapacitors.

It is a great challenge to ideally integrate graphene with its unique two-dimensional (2D) and porous structure into the pseudocapacitive materials. In this paper, a simple technique, i.e. direct-laser-writing (DLW), was developed to fabricate microsupercapacitors (MSCs) with excellent electrochemical performance, marked as Ni-Co-S/laser induced graphene (LIG) that exhibit a high areal specific capacitance of 680 mF cm-2 at the current density of 1 mA cm-2. A symmetric MSC device was assembled using Ni-Co-S/LIG as a positive electrode and active carbon (AC) as the negative electrode, and exhibited a high areal energy density of 56.9 µW h cm-2 at the power density of 800 µW cm-2, and excellent cycling stability maintaining 89.6% of the areal specific capacitance after 8000 cycles. The synergistic effect of bimetallic Ni-Co-S and the LIG with the 2D structure results in the excellent electrochemical performance. This work demonstrates a method to integrate Ni-Co-S pseudocapacitive materials into porous graphene with a direct-laser-writing technique. The produced integrated materials possess high energy density that can be used in MSCs.

Hexafluoroisopropanol-Mediated Redox-Neutral α-C(sp3)-H Functionalization of Cyclic Amines via Hydride Transfer.

Hexafluoroisopropanol has been demonstrated as the versatile promoter for redox-neutral α-C(sp3)-H functionalization of cyclic amines via the cascade [1,5]-hydride transfer/cyclization strategy. A wide range of cyclic amines are functionalized into bioactive tetrahydroquinolines, quinazolines, benzoxazines, and benzotriazepines in moderate to excellent yields. This protocol features additive-free conditions, operational simplicity, and wide substrate scope.

Selenium concentration, dietary intake and risk of hepatocellular carcinoma - A systematic review with meta-analysis / Concentración de selenio, ingesta dietética y riesgo de carcinoma hepatocelular: revisión sistemática con metaanálisis

Aim: this study was performed to investigate the association between selenium concentrations, dietary intake, and the risk of hepatocellular carcinoma (HCC). Methods: we identified eligible studies in PubMed and EMBASE databases, in addition to the reference lists of original studies and review articles on this topic, up to 1 Feb 2019. A summary of standardized mean differences (SMD) with 95% confidence intervals (CI) was calculated using a random-effects model. Heterogeneity between studies was assessed using Cochran Q and I2 statistics. Results: finally, a meta-analysis showed that dietary intake of selenium and tissue selenium concentration were not associated with HCC risk (dietary SMD = -0.11, 95% CI: -0.26 to 0.03; tissue SMD = -0.12, 95% CI: -0.56 to 0.33). However, samples from toenail, whole blood, and serum all showed an inverse association with HCC risk (toenail SMD = -0.53, 95% CI: -0.72 to -0.35; whole blood SMD = -2.21, 95% CI: -2.67 to -1.76; tissue SMD = -1.26, 95% CI: -1.71 to -0.81). Dose-response data from few studies showed that an extra increase in serum selenium was dramatically related with a lower risk of HCC (adjusted p-trend < 0.05). This study showed that selenium concentration in toenail, whole blood and serum was inversely associated with HCC risk. Conclusion: increased concentration in serum selenium was related to a lower risk of HCC. However, these results based on dietary intake and tissue samples, which included few studies, did not reach statistical significance

Objetivo: este estudio se realizó para investigar la asociación entre las concentraciones de selenio, la ingesta dietética y el riesgo de carcinoma hepatocelular (CHC). Métodos: identificamos estudios elegibles en las bases de datos PubMed y EMBASE, además de las listas de referencias de los estudios originales y artículos de revisión sobre este tema hasta el 1 de febrero de 2019. Se realizó un resumen de las diferencias medias estandarizadas (SMD) con intervalos de confianza (CI) del 95% utilizando un modelo de efectos aleatorios. La heterogeneidad entre estudios se evaluó utilizando las estadísticas de Cochran Q e I2. Resultados: por último, el metaanálisis mostró que la concentración de selenio en la ingesta dietética y de selenio tisular no estaban asociadas al riesgo de HCC (SMD dietética -0,11, IC 95%: -0,26 a 0,03; SMD tisular -0,12, IC 95%: -0,56 a 0,33). Sin embargo, las muestras de uña del pie, sangre entera y suero mostraron todas ellas una asociación inversa con el riesgo de CHC (SMD ungueal -0.53, IC 95%: -0.72 a -0.35; SMD de sangre entera -2.21, IC 95%: -2.67 a -1.76; SMD tisular -1.26, IC 95%: -1.71 a -0.81). Los datos de dosis-respuesta de pocos estudios mostraron que los incrementos del selenio sérico se relacionaban fuertemente con un menor riesgo de CHC (tendencia de p ajustada < 0.05). Este estudio demostró que la concentración de selenio en las uñas del pie, en sangre entera y en suero se asocian inversamente al riesgo de CHC. Conclusión: el aumento de la concentración de selenio sérico se relacionó con menor riesgo de CHC. Sin embargo, los resultados de la ingesta dietética y los tejidos, que incluían pocos estudios, no alcanzaron la significación estadística

Selenium concentration, dietary intake and risk of hepatocellular carcinoma - A systematic review with meta-analysis.

INTRODUCTION: Aim: this study was performed to investigate the association between selenium concentrations, dietary intake, and the risk of hepatocellular carcinoma (HCC). Methods: we identified eligible studies in PubMed and EMBASE databases, in addition to the reference lists of original studies and review articles on this topic, up to 1 Feb 2019. A summary of standardized mean differences (SMD) with 95% confidence intervals (CI) was calculated using a random-effects model. Heterogeneity between studies was assessed using Cochran Q and I2 statistics. Results: finally, a meta-analysis showed that dietary intake of selenium and tissue selenium concentration were not associated with HCC risk (dietary SMD = -0.11, 95% CI: -0.26 to 0.03; tissue SMD = -0.12, 95% CI: -0.56 to 0.33). However, samples from toenail, whole blood, and serum all showed an inverse association with HCC risk (toenail SMD = -0.53, 95% CI: -0.72 to -0.35; whole blood SMD = -2.21, 95% CI: -2.67 to -1.76; tissue SMD = -1.26, 95% CI: -1.71 to -0.81). Dose-response data from few studies showed that an extra increase in serum selenium was dramatically related with a lower risk of HCC (adjusted p-trend < 0.05). This study showed that selenium concentration in toenail, whole blood and serum was inversely associated with HCC risk. Conclusion: increased concentration in serum selenium was related to a lower risk of HCC. However, these results based on dietary intake and tissue samples, which included few studies, did not reach statistical significance.

INTRODUCCIÓN: Objetivo: este estudio se realizó para investigar la asociación entre las concentraciones de selenio, la ingesta dietética y el riesgo de carcinoma hepatocelular (CHC). Métodos: identificamos estudios elegibles en las bases de datos PubMed y EMBASE, además de las listas de referencias de los estudios originales y artículos de revisión sobre este tema hasta el 1 de febrero de 2019. Se realizó un resumen de las diferencias medias estandarizadas (SMD) con intervalos de confianza (CI) del 95% utilizando un modelo de efectos aleatorios. La heterogeneidad entre estudios se evaluó utilizando las estadísticas de Cochran Q e I2. Resultados: por último, el metaanálisis mostró que la concentración de selenio en la ingesta dietética y de selenio tisular no estaban asociadas al riesgo de HCC (SMD dietética -0,11, IC 95%: -0,26 a 0,03; SMD tisular -0,12, IC 95%: -0,56 a 0,33). Sin embargo, las muestras de uña del pie, sangre entera y suero mostraron todas ellas una asociación inversa con el riesgo de CHC (SMD ungueal -0.53, IC 95%: -0.72 a -0.35; SMD de sangre entera -2.21, IC 95%: -2.67 a -1.76; SMD tisular -1.26, IC 95%: -1.71 a -0.81). Los datos de dosis-respuesta de pocos estudios mostraron que los incrementos del selenio sérico se relacionaban fuertemente con un menor riesgo de CHC (tendencia de p ajustada < 0.05). Este estudio demostró que la concentración de selenio en las uñas del pie, en sangre entera y en suero se asocian inversamente al riesgo de CHC. Conclusión: El aumento de la concentración de selenio sérico se relacionó con menor riesgo de CHC. Sin embargo, los resultados de la ingesta dietética y los tejidos, que incluían pocos estudios, no alcanzaron la significación estadística.

Controllable Syntheses of Spiroindolenines and Benzazepinoindoles via Hexafluoroisopropanol-Mediated Redox-Neutral Cascade Process.

The pharmaceutically intriguing spiroindolenines incorporating tetrahydroquinoline were constructed via a hexafluoroisopropanol-promoted redox-neutral cascade cyclization from readily available starting materials. The benzazepinoindole skeletons could also be facilely accessed via one-pot sequential operation. Distinctive features of these transformations include their controllable access of the two privileged skeletons, high efficiency, simple operation, and mild reaction conditions.

Non-additional carbon source one-step synthesis of Bi2O2CO3-based ternary composite for efficient Z-scheme photocatalysis.

Bi2O2CO3-based ternary composite materials are generally synthesized by two- or multi-step method and special precursor of CO32- is usually utilized in synthesis of Bi2O2CO3, which are time-consuming, laborious and relatively costly. In this paper, for the first time, a facile one-step solvothermal method is used to fabricate Z-scheme Bi2O2CO3/Bi/Bi2WO6 ternary composites. Interestingly, ethylene glycol not only acts as solvent for the reaction system, but also reduced Bi3+ into metallic Bi and itself is oxidized to CO32-, which could construct Bi2O2CO3. On this occasion, Bi2O2CO3/Bi/Bi2WO6 ternary composites are obtained after one-step method. High resolution transmission electron microscopy clearly reveals each component in composites. The as-prepared samples could be applied in various photocatalytic activities. Under solar light irradiation, Bi2O2CO3/Bi/Bi2WO6 composites exhibited prominent photodegradation performances for both ciprofloxacin and bisphenol A. Meanwhile, these composites could also be used in efficient photoreduction of CO2. The efficient photocatalytic activity could be mainly ascribed to Z-scheme electron transfer mechanism in ternary composites, which is determined by surface redox reactions, active species trapping experiment, electron spin resonance spectrum.

N-Terminal Domain Truncation and Domain Insertion-Based Engineering of a Novel Thermostable Type I Pullulanase from Geobacillus thermocatenulatus.

A novel thermostable type I pullulanase gene ( pul GT) from Geobacillus thermocatenulatus DSMZ730 was cloned. It has an open reading frame of 2154 bp encoding 718 amino acids. G. thermocatenulatus pullulanase (PulGT) was found to be optimally active at pH 6.5 and 70 °C. It exhibited stable activity in the pH range of 5.5-7.0. PulGT lacked three domains (CBM41 domain, X25 domain, and X45 domain) compared with the pullulanase from Bacillus acidopullulyticus ( 2WAN ). Different N-terminally domain truncated (730T) or spliced (730T-U1 and 730T-U2) mutants were constructed. Truncating the N-terminal 85 amino acids decreased the Km value and did not change its optimum pH, an advantageous biochemical property in some applications. Compared with 2WAN , PulGT can be used directly for maize starch saccharification without adjusting the pH, which reduces cost and improves efficiency.

Taxonomy characterization and plumbum bioremediation of novel fungi.

The objective of this study was to investigate the screening, taxonomy characterization, Pb biosorption, and application of the high Pb-resistant fungus F1 separated from the heavy metal contaminated soil. Fungus F1 was screened through metal concentration gradient ranging from 25 to 4000 mg L-1 . The internal transcribed spacers (ITS) of the strain was analyzed by molecular biotechnology. The adsorption conditions were also evaluated. The precipitation of fungus F1 was analyzed by Scanning Electron Microscopy (SEM), Fourier transformer infrared spectroscopy (FTIR) and energy dispersive X-ray (EDX) techniques. The Pb speciation was determined by BCR three-step sequential extraction. The highest concentration of fungus F1 resistance to Pb2+ was 3500 mg L-1 . The fungus was identified as Trichoderma asperellum. The optimum condition for the Pb2+ removal rate was discovered as follows: MTL: 3500 mg L-1 ; pH: 7; Pb2+ concentration: 800 mg L-1 ; temperature was 30 °C; initial biosorbent dosage: 6% (v/v). The surface chemical functional groups of fungus F1 were amino, hydroxyl, and carbonyl groups, which may be involved in the biosorption of Pb. Application test showed that the exchangeable, acid-and water soluble Pb were reduced, and the sulfide, organic combination state, and residual Pb were increased. With the preferable absorption capacity, fungus F1 was considered to have good prospects of bioremediation.

Transesterification Synthesis of Chloramphenicol Esters with the Lipase from Bacillus amyloliquefaciens.

This work presents a synthetic route to produce chloramphenicol esters by taking advantage the high enantio- and regio-selectivity of lipases. A series of chloramphenicol esters were synthesized using chloramphenicol, acyl donors of different carbon chain length and lipase LipBA (lipase cloned from Bacillus amyloliquefaciens). Among acyl donors with different carbon chain lengths, vinyl propionate was found to be the best. The influences of different organic solvents, reaction temperature, reaction time, enzyme loading and water content on the synthesis of the chloramphenicol esters were studied. The synthesis of chloramphenicol propionate (0.25 M) with 4.0 g L-1 of LipBA loading gave a conversion of ~98% and a purity of ~99% within 8 h at 50 °C in 1,4-dioxane as solvent. The optimum mole ratio of vinyl propionate to chloramphenicol was increased to 5:1. This is the first report of B. amyloliquefaciens lipase being used in chloramphenicol ester synthesis and a detailed study of the synthesis of chloramphenicol propionate using this reaction. The high enzyme activity and selectivity make lipase LipBA an attractive catalyst for green chemical synthesis of molecules with complex structures.

The protective effect of North Schisandra Lignans on vascular endothelial cell oxidation injuries.

BACKGROUND: In this study, the authors cultivated ECV-304 in vitro and incubated cells with H2O2, established injury models, and induced oxidized endothelial cell apoptosis. This model makes it possible to choose suitable concentrations of North Schisandra Lignans. OBJECTIVE: To study the protective effects of North Schisandra Lignans on human umbilical vein endothelial cell injuries. METHODS: Endothelial cell growth and proliferation activity were detected through the MTT method. The colorimetric method was used to determine superoxide dismutase (SOD) activity in the cell culture solution, as well as malondialdehyde (MDA) content in the cell. RESULTS: North Schisandra Lignans noticeably decreased ECV-304 cell injury induced by H2O2. Moderate and high concentrations of North Schisandra Lignans could significantly lower MDA content and heighten SOD activity. These differences were significant compared to the H2O2 group (P< 0.05). CONCLUSIONS: North Schisandra Lignans had an obvious protective effect on ECV-304 injured by H2O2$. The mechanism decreases MDA production and heightened SOD activity.

Effects of cultural medium on the formation and antitumor activity of polysaccharides by Cordyceps gunnii.

The effects of culture medium composition (i.e., carbon and nitrogen sources) on the growth of mycelia, molecular weight distribution and antitumor activity of intracellular polysaccharides (IPS) from Cordyceps gunnii were investigated. Sucrose and peptone were proved to be the best carbon and nitrogen sources for mycelia growth and remarkably improved IPS production. When the sucrose concentration was 2.0%, the mycelium yield reached up to 15.94±1.26 g/L, but with lower IPS yield; whereas the sucrose concentration was 4.5%, IPS yield reached to a maximum of 138.78±3.89 mg/100 mL. The effects of different carbon/nitrogen (C/N) ratios with equal amounts of carbon source matter on the mycelia and IPS formation were optimized. It found that the yield of mycelia and IPS were both reached to the highest at a C/N ratio of 10:3. In addition, the IPS had the highest macro molecular polysaccharide content and antitumor activity when sucrose concentration was 3.5% and the C/N ratio was 10:1.5. Thus, there was a positive correlation between molecular weight distribution and antitumor activity of IPS by C. gunnii.

Efficient synthesis and activity of beneficial intestinal flora of two lactulose-derived oligosaccharides.

Lactulose is considered as a prebiotic because it promotes the intestinal proliferation of Lactobacillus acidophilus which is added to various milk products. Moreover, lactulose is used in pharmaceuticals as a gentle laxative and to treat hyperammonemia. This study was aimed at the total synthesis of two Lactulose-derived oligosaccharides: one is 3-O-ß-d-galactopyranosyl-d-fructose, d-fructose and ß-d-galactose bounded together with ß-1,3-glycosidic bound, the other is 1-O-ß-d-galactopyranosyl-d-fructose, d-fructose and ß-d-galactose bounded together with ß-1,1-glycosidic bound, which were accomplished in seven steps from d-fructose and ß-d-galactose and every step of yield above 75%. This synthetic route provided a practical and effective synthetic strategy for galactooligosaccharides, starting from commercially available monosaccharides. Then we evaluated on their prebiotic properties in the search for potential agents of regulating and improving the intestinal flora of human. The result showed that the prebiotic properties of Lactulose-derived oligosaccharides was much better than Lactulose. Among them, 3-O-ß-d-galactopyranosyl-d-fructose displayed the most potent activity of proliferation of L. acidophilus.

Effects of extraction methods on the yield, chemical structure and anti-tumor activity of polysaccharides from Cordyceps gunnii mycelia.

This study was to investigate the effects of different extraction methods on the yield, chemical structure and antitumor activity of polysaccharides from Cordyceps gunnii (C. gunnii) mycelia. Five extraction methods were used to extract crude polysaccharides (CPS), which include room-temperature water extraction (RWE), hot-water extraction (HWE), microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and cellulase-assisted extraction (CAE). Then Sephadex G-100 was used for purification of CPS. As a result, the antitumor activities of CPS and PPS on S180 cells were evaluated. Five CPS and purified polysaccharides (PPS) were obtained. The yield of CPS by microwave-assisted extraction (CPSMAE) was the highest and its anti-tumor activity was the best and its macromolecular polysaccharide (3000-1000kDa) ratio was the largest. The PPS had the same monosaccharide composition, but their obvious difference was in the antitumor activity and the physicochemical characteristics, such as intrinsic viscosity, specific rotation, scanning electron microscopy and circular dichroism spectra.

Influence of fermentation conditions on polysaccharide production and the activities of enzymes involved in the polysaccharide synthesis of Cordyceps militaris.

The influence of different fermentation conditions on intracellular polysaccharide (IPS) production and activities of the phosphoglucomutase (PGM), UDPG-pyrophosphorylase (UGP), phosphoglucose isomerase (PGI), UDPG-dehydrogenase (UGD), and glucokinase (GK) implicated in metabolite synthesis in Cordyceps militaris was evaluated. The highest IPS production (327.57 ± 6.27 mg/100 mL) was obtained when the strain was grown in the optimal medium containing glucose (40 g · L(-1)), beef extract (10 g · L(-1)), and CaCO3 (0.5 g · L(-1)), and the initial pH and temperature were 7 and 25 °C, respectively. The activities of PGM, UGP, and PGI were proved to be influenced by the fermentation conditions. A strong correlation between the activities of these enzymes and the production of IPS was found. The transcription level of the pgm gene (encoding PGM) was 1.049 times and 1.467 times compared to the ugp gene and pgi gene (encoding UGP and PGI), respectively, in the optimal culture medium. This result indicated that PGM might be the highly key enzyme to regulate the biosynthesis of IPS of C. militaris in a liquid-submerged culture. Our study might be helpful for further research on the pathway of polysaccharide biosynthesis aimed to improve the IPS production of C. militaris.

Isolation of an abscisic acid senescence and ripening inducible gene from litchi and functional characterization under water stress.

A full-length abscisic acid (ABA) senescence and ripening inducible gene named LcAsr was obtained from litchi. Bioinformatic analysis showed that full-length LcAsr was 1,177 bp and contained an open reading frame (ORF) encoding 153 amino acids, 85- and 146-bp 5' and 3' UTRs, respectively. LcAsr was expressed in all organs, with preferential expression in the flower and low levels in pulp. The expression level of LcAsr in postharvest uncovered fruit reached a maximum at 24 h after harvest. When the litchi fruit was covered with plastic film, the LcAsr expression level remained constant. LcASR protein localized in the nucleus. LcAsr was transformed in Arabidopsis thaliana L. (ecotype Columbia) and four transgenic lines were obtained. One line, 35S::LcAsrD, was selected for drought tolerance analysis and showed higher tolerance to drought than the control. The activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase were much higher in the transgenic line than the control under drought conditions. The levels of several ABA/stress-regulated genes were investigated. The transcript level of responsive to ABA (RAB18) remained constant and responsive to dehydration (RD29A) displayed a slight decrease in the Columbia line (Col). However, the transcript levels of LcAsr, RAB18, and RD29A were greatly enhanced in the transgenic 35S::LcAsrD. The transcript levels of KAT1, KAT2, and SKOR were also markedly decreased in the transgenic line. These results suggest an important role of LcAsr as a protective molecule for water deficit and help to understand the molecular mechanism of postharvest litchi fruit dehydration.