Novel link between prostaglandin E2 (PGE2) and cholinergic signaling in lung cancer: The role of c-Jun in PGE2-induced α7 nicotinic acetylcholine receptor expression and tumor cell proliferation

BACKGROUND

Cyclooxygenase-2-derived prostaglandin E2 (PGE2) stimulates tumor cell growth and progression. α7 nicotinic acetylcholine receptor (nAChR) is a major mediator of cholinergic signaling in tumor cells. In the present study, we investigated the mechanisms by which PGE2 increases non-small cell lung cancer (NSCLC) proliferation via α7 nAChR induction.

METHODS

The effects of PGE2 on α7 nAChR expression, promoter activity, and cell signaling pathways were detected by Western blot analysis, real time reverse transcriptase polymerase chain reaction, and transient transfection assay. The effect of PGE2 on cell growth was determined by cell viability assay.

RESULTS

We found that PGE2 induced α7 nAChR expression and its promoter activity in NSCLC cells. The stimulatory role of PGE2 on cell proliferation was attenuated by α7 nAChR small interfering ribonucleic acids (siRNA) or acetylcholinesterase. PGE2-induced α7 nAChR expression was blocked by an antagonist of the PGE2 receptor subtype EP4 and by EP4 siRNA. Furthermore, PGE2 enhanced α7 nAChR expression via activation of c-Jun N-terminal kinase (JNK), phosphatidylinositol 3-kinase (PI3-K), and protein kinase A (PKA) pathways followed by increased c-Jun expression, a critical transcription factor. Blockade of c-Jun diminished the effects of PGE2 on α7 nAChR promoter activity and protein expression, and cell growth.

CONCLUSION

Our results demonstrate that PGE2 promotes NSCLC cell growth through increased α7 nAChR expression. This effect is dependent on EP4-mediated activation of JNK, PI3K, and PKA signals that induce c-Jun protein expression and α7 nAChR gene promoter activity. Our findings unveil a novel link between prostanoids and cholinergic signaling.

Simultaneous construction of PCR-DGGE-based predictive models of Listeria monocytogenes and Vibrio parahaemolyticus on cooked shrimps

The aim of this study was to simultaneously construct PCR-DGGE-based predictive models of Listeria monocytogenes and Vibrio parahaemolyticus on cooked shrimps at 4 and 10°C. Calibration curves were established to correlate peak density of DGGE bands with microbial counts. Microbial counts derived from PCR-DGGE and plate methods were fitted by Baranyi model to obtain molecular and traditional predictive models. For L. monocytogenes, growing at 4 and 10°C, molecular predictive models were constructed. It showed good evaluations of correlation coefficients (R(2) > 0.92), bias factors (Bf ) and accuracy factors (Af ) (1.0 ≤ Bf ≤ Af ≤ 1.1). Moreover, no significant difference was found between molecular and traditional predictive models when analysed on lag phase (λ), maximum growth rate (μmax ) and growth data (P > 0.05). But for V. parahaemolyticus, inactivated at 4 and 10°C, molecular models show significant difference when compared with traditional models. Taken together, these results suggest that PCR-DGGE based on DNA can be used to construct growth models, but it is inappropriate for inactivation models yet. This is the first report of developing PCR-DGGE to simultaneously construct multiple molecular models.

SIGNIFICANCE AND IMPACT OF THE STUDY

It has been known for a long time that microbial predictive models based on traditional plate methods are time-consuming and labour-intensive. Denaturing gradient gel electrophoresis (DGGE) has been widely used as a semiquantitative method to describe complex microbial community. In our study, we developed DGGE to quantify bacterial counts and simultaneously established two molecular predictive models to describe the growth and survival of two bacteria (Listeria monocytogenes and Vibrio parahaemolyticus) at 4 and 10°C. We demonstrated that PCR-DGGE could be used to construct growth models. This work provides a new approach to construct molecular predictive models and thereby facilitates predictive microbiology and QMRA (Quantitative Microbial Risk Assessment).

Sesquiterpenoids isolated from an endophyte fungus Diaporthe sp

Ten new sesquiterpenoids including six brasilane-type sesquiterpenoids, diaporols J–O (1–6), a 3,6-cycloprecapnellane sesquiterpenoid, diaporol P (7), and three drimane sesquiterpenoids, diaporols Q–S (8–10) were isolated from Diaporthe sp.

Morphological and molecular diversification of Asian endemic Difflugia tuberspinifera (Amoebozoa, Arcellinida): a case of fast morphological evolution in protists?

Planktonic arcellinid testate amoebae exhibit a broad-range of morphological variability but it is currently unclear to what extent this variability represents phenotypic plasticity or if it is genetically determined. We investigated the morphology and phylogenetic relationships of three endemic east-asian Difflugia taxa 1) the vase-shaped D. mulanensis, 2) and a spinose and a spineless morphotypes of D. tuberspinifera using scanning electron microscopy and two ribosomal genetic markers (SSU rDNA and ITS sequences). Our phylogenetic analyses shows that all three taxa are genetically distinct and closely related to D. achlora and Netzelia oviformis. The genetic variations between the spineless and spinose morphotypes of D. tuberspinifera were low at the SSU rRNA level (0.4%), but ten times higher at the ITS level (4.5-6%). Our data suggest that the two forms of D. tuberspinifera are sufficiently differentiated in terms of morphology and genetic characteristics to constitute two separate entities and that the presence of spines does not result from phenotypic plasticity due to environmental selective pressure. However further observational and experimental data are needed to determine if these two forms constitute different biological species.

New tricycloalternarenes from fungus Alternaria sp

Two new tricycloalternarenes I (1) and J (2), together with five known derivatives (3-7), were isolated from the culture of marine fungus Alternaria sp. The structures were elucidated by a combination of spectroscopic approach ((1)H, (13)C NMR, HMBC, COSY, and NOESY) and the low-temperature (100 K) single-crystal X-ray crystallography analysis. The antimicrobial assays of tricycloalternarenes I (1) and J (2) were tested.

Therapeutic effects of fucoidan in 6-hydroxydopamine-lesioned rat model of Parkinson's disease: Role of NADPH oxidase-1

AIMS

To explore the effect of fucoidan treatment on oxidative stress-mediated dopaminergic neuronal damage and its potential mechanisms.

METHODS

The effect of fucoidan was investigated in a 6-hydroxydopamine (6-OHDA) rat model of PD, an animal model considered appropriate for preclinical studies of PD therapy. The effects of fucoidan treatment on animal behavior and the survival ratio of dopaminergic neurons were investigated. We further observed the effect of fucoidan on microglia and the NADPH oxidases-1 (Nox1), a family of enzymes generating reactive oxygen species (ROS).

RESULTS

We found that chronic fucoidan administration mitigated the motor dysfunction induced by 6-OHDA. Similarly, fucoidan reduced the loss of DA neurons in the SNc and DA fibers in the striatum in 6-OHDA-lesioned rats. Moreover, we found that fucoidan inhibited the 6-OHDA-stimulating expression of Nox1 in both tyrosine hydroxylase (TH)-positive neurons and non-TH-positive neurons, prevented Nox1-sensitive oxidative stress and cell damage in SNc neurons. Fucoidan also effectively inhibited nigral microglial activation.

CONCLUSION

These results support the beneficial effect of fucoidan in 6-OHDA-lesioned rat model of PD. Fucoidan may suppress the Nox1-triggered oxidative stress in the SNc to protect DA neurons from 6-OHDA-induced toxicity and achieve its beneficial effect.

[Cloning and prokaryotic expression analysis of HDS from Salvia miltiorrhiza bge.f.alba]

According to the designed specific primers of gene fragment based on the Salvia miltiorrhiza transcriptome data, with the method of reverse transcription polymerase chain reaction (RT-PCR), this study cloned full-length cDNA sequence of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase gene from Salvia miltiorrhiza bge.f.alba, this sequence is named as SmHDS and its GenBank registration number is KJ746807. SmHDS, 2 529 bp long, contains an ORF of 2 229 bp, encodes 742 amino acids, including 5' UTR 170 bp and 3' UTR 130 bp. Using bioinformatics software, having made a homology analysis of the obtained sequence, we can have a conclusion that SmHDS have a close genetic relationship with HDS of Salvia miltiorrhiza. Analysis result of prokaryotic expression revealed that in Escherichia coli, SmHDS expressed target proteins which in size are comparable with the protein predicted. Meanwhile, the 4 factors which can influence the protein expression were optimized, the 4 factors are inducing temperature, inducing time, IPTG concentrations and density of inducing host bacterium (A600). The optimal expression conditions of SmHDS were 30 degrees C until the A600 is 0.6, and add IPTG to a final concentration of 0.2 mmol x L(-1), and the induction time of 20 h. It provides theoretical basis for the further study of the function of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase in the biosynthesis of tanshinone compounds.

Identification of species and materia medica within Angelica L. (Umbelliferae) based on phylogeny inferred from DNA barcodes

DNA barcodes have been increasingly used in authentication of medicinal plants, while their wide application in materia medica is limited in their accuracy due to incomplete sampling of species and absence of identification for materia medica. In this study, 95 leaf accessions of 23 species (including one variety) and materia medica of three Pharmacopoeia-recorded species of Angelica in China were collected to evaluate the effectiveness of four DNA barcodes (rbcL, matK, trnH-psbA and ITS). Our results showed that ITS provided the best discriminatory power by resolving 17 species as monophyletic lineages without shared alleles and exhibited the largest barcoding gap among the four single barcodes. The phylogenetic analysis of ITS showed that Levisticum officinale and Angelica sinensis were sister taxa, which indicates that L. officinale should be considered as a species of Angelica. The combination of ITS + rbcL + matK + trnH-psbA performed slight better discriminatory power than ITS, recovering 23 species without shared alleles and 19 species as monophyletic clades in ML tree. Authentication of materia medica using ITS revealed that the decoction pieces of A. sinensis and A. biserrata were partially adulterated with those of L. officinale, and the temperature around 80 °C processing A. dahurica decoction pieces obviously reduced the efficiency of PCR and sequencing. The examination of two cultivated varieties of A. dahurica from different localities indicated that the four DNA barcodes are inefficient for discriminating geographical authenticity of conspecific materia medica. This study provides an empirical paradigm in identification of medicinal plants and their materia medica using DNA barcodes.

Cytotoxic and antimicrobial flavonoids from Cryptocarya concinna

Five new flavonoids, cryptoconones A-E (1-5), along with six known compounds (6-11), were isolated from the stems of Cryptocarya concinna. The structures of these compounds were elucidated on the basis of spectroscopic data interpretation, and the absolute configurations were determined via circular dichroism spectra and X-ray crystal analysis. The cytotoxic and antimicrobial activities of these compounds were also evaluated. Compounds 9 and 10 exhibited moderate cytotoxic activities against HCT116, HT-29, SW480, and MDA-MB-231 cell lines with IC50 values ranging from 6.25 to 9.35 µM. Compounds 8 and 11 exhibited antimicrobial activity against Fusarium moniliforme and Botrytis cinerea, respectively, with the same minimum inhibitory concentration of 5 µg/mL.

Reflective properties of randomly rough surfaces under large incidence angles

The reflective properties of randomly rough surfaces at large incidence angles have been reported due to their potential applications in some of the radiative heat transfer research areas. The main purpose of this work is to investigate the formation mechanism of the specular reflection peak of rough surfaces at large incidence angles. The bidirectional reflectance distribution function (BRDF) of rough aluminum surfaces with different roughnesses at different incident angles is measured by a three-axis automated scatterometer. This study used a validated and accurate computational model, the rigorous coupled-wave analysis (RCWA) method, to compare and analyze the measurement BRDF results. It is found that the RCWA results show the same trend of specular peak as the measurement. This paper mainly focuses on the relative roughness at the range of 0.16<σ/λ<5.35. As the relative roughness decreases, the specular peak enhancement dramatically increases and the scattering region significantly reduces, especially under large incidence angles. The RCWA and the Rayleigh criterion results have been compared, showing that the relative error of the total integrated scatter increases as the roughness of the surface increases at large incidence angles. In addition, the zero-order diffractive power calculated by RCWA and the reflectance calculated by Fresnel equations are compared. The comparison shows that the relative error declines sharply when the incident angle is large and the roughness is small.

Thermal decomposition of ammonium perchlorate in the presence of Al(OH)(3)·Cr(OH)(3) nanoparticles

An Al(OH)(3)·Cr(OH)(3) nanoparticle preparation procedure and its catalytic effect and mechanism on thermal decomposition of ammonium perchlorate (AP) were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TG-DSC), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis and mass spectroscopy (TG-MS). In the preparation procedure, TEM, SAED, and FT-IR showed that the Al(OH)(3)·Cr(OH)(3) particles were amorphous particles with dimensions in the nanometer size regime containing a large amount of surface hydroxyl under the controllable preparation conditions. When the Al(OH)(3)·Cr(OH)(3) nanoparticles were used as additives for the thermal decomposition of AP, the TG-DSC results showed that the addition of Al(OH)(3)·Cr(OH)(3) nanoparticles to AP remarkably decreased the onset temperature of AP decomposition from approximately 450°C to 245°C. The FT-IR, RS and XPS results confirmed that the surface hydroxyl content of the Al(OH)(3)·Cr(OH)(3) nanoparticles decreased from 67.94% to 63.65%, and Al(OH)3·Cr(OH)3 nanoparticles were limitedly transformed from amorphous to crystalline after used as additives for the thermal decomposition of AP. Such behavior of Al(OH)(3)·Cr(OH)(3) nanoparticles promoted the oxidation of NH3 of AP to decompose to N2O first, as indicated by the TG-MS results, accelerating the AP thermal decomposition.

[Prospect and application of microsatellite population genetics in study of geoherbs]

The author introduces the basic concepts of microsatellite and population genetics and its characteristics, expounds the application of these theories for population genetic structure and genetic diversity, gene flow and evolutionary significant unit ESU division research. This paper discuss its applicationin study of genetic causes, origin of cultivation, different regional origins of geoherbs, aiming at providing a new theory and method for geoherbs.

An ultrasound study of altered hydration behaviour of proteoglycan-degraded articular cartilage

BACKGROUND

Articular cartilage is a solid-fluid biphasic material covering the bony ends of articulating joints. Hydration of articular cartilage is important to joint lubrication and weight-wearing. The aims of this study are to measure the altered hydration behaviour of the proteoglycan-degraded articular cartilage using high-frequency ultrasound and then to investigate the effect of proteoglycan (PG) degradation on cartilage hydration.

METHODS

Twelve porcine patellae with smooth cartilage surface were prepared and evenly divided into two groups: normal group without any enzyme treatment and trypsin group treated with 0.25% trypsin solution for 4 h to digest PG in the tissue. After 40-minute exposure to air at room temperature, the specimens were immerged into the physiological saline solution. The dehydration induced hydration behaviour of the specimen was monitored by the high-frequency (25 MHz) ultrasound pulser/receiver (P/R) system. Dynamic strain and equilibrium strain were extracted to quantitatively evaluate the hydration behaviour of the dehydrated cartilage tissues.

RESULTS

The hydration progress of the dehydrated cartilage tissue was observed in M-mode ultrasound image indicating that the hydration behaviour of the PG-degraded specimens decreased. The percentage value of the equilibrium strain (1.84 ± 0.21%) of the PG-degraded cartilage significantly (p < 0.01) decreased in comparison with healthy cartilage (3.46 ± 0.49%). The histological sections demonstrated that almost PG content in the entire cartilage layer was digested by trypsin.

CONCLUSION

Using high-frequency ultrasound, this study found a reduction in the hydration behaviour of the PG-degraded cartilage. The results indicated that the degradation of PG decreased the hydration capability of the dehydrated tissue. This study may provide useful information for further study on changes in the biomechanical property of articular cartilage in osteoarthritis.

PTEN hypermethylation profiles of Chinese Kazakh patients with esophageal squamous cell carcinoma

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes (TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma (ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC (n = 95) and healthy individuals (n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [IQR]: 7.0-11.0%) in patients with ESCC and 6.0% in controls (IQR: 4.0-9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls (P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC (P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis.

Radiofrequency ablation technique in the treatment of liver tumours: review and future issues

Thermal ablation is increasingly being used for treatment of liver tumours. Among the techniques of thermal ablation, radiofrequency ablation (RF) is undoubtedly being used most frequently because of its advantages, such as morbidity and mortality rates, effective tumour ablation, as well as being less time-consuming. This paper presents the state of the art of RF ablation technique. This includes the theoretical development, experimental study and clinical application of the radiofrequency ablation technique. First, it introduces the principle of this technique. Second, it shows the development of this technique and valuable achievements. These achievements include the device, strategy of operation and extension to other diseases. Third, it concludes future issues to be addressed in order to further advance this technique.

[Effects of low temperature stress on photosynthetic performance of different genotypes wheat cultivars]

Different genotypes wheat cultivars (spring wheat Yangmai 18, semi-spring wheat Zhengmai 9023, and semi-winter wheat Yannong 19) were chosen to study their photosynthetic and chlorophyll fluorescence characteristics at tillering and stem elongation stages under low temperature stress. After treated with low temperature (-10 degrees C at night) at tillering stage for 2 days, the net photosynthetic rate (Pn), stomata conductance (g(s)), maximum quantum yield of PSII (Fv/Fm), photochemical quenching (q(P)), non-photochemical quenching coefficient (NPQ), and acyclic photosynthetic electron transfer rate of PSII (ETR) of Yannong 19 were significantly higher than those of Yangmai 18 and Zhengmai 9023, the g(s), Fv/Fm, qP, and NPQ of Zhengmai 9023 were significantly higher than those of Yangmai 18, while the intercellular CO2 concentration (Ci) of Yannong 19 was significantly lower than that of Zhengmai 9023 and Yangmai 18. In addition, the minimal fluorescence (Fo) of Yangmai 18 was significantly higher than that of Zhengmai 9023 and Yannong 19. Similarly, after treated with low temperature (0 degrees C at night) at stem elongation stage for 3 days, the Pn, g(s), qP, and Fv/Fm of Yannong 19 were significantly higher than those of Yangmai 18 and Zhengmai 9023, and the NPQ and ETR of Yannong 19 were significantly higher than those of Yangmai 18. In addition, the Pn, g(s), Fv/Fm, and qP of Zhengmai 9023 were significantly higher than those of Yangmai 18, the Fo of Zhengmai 9023 was significantly higher than that of Yannong 19, and the Ci and Fo of Yangmai 18 were significantly higher than those of Zhengmai 9023 and Yannong 19. It was suggested that under low temperature stress at tillering and stem elongation stages, semi-winter wheat Yannong 19 had the highest photosynthetic activity and the best self-protection mechanism, followed by semi-spring wheat Zhengmai 9023, and spring wheat Yangmai 18.

A component of the Sec61 ER protein transporting pore is required for plant susceptibility to powdery mildew

Biotrophic pathogens, like the powdery mildew fungi, require living plant cells for their growth and reproduction. During infection, a specialized structure called the haustorium is formed by the fungus. The haustorium is surrounded by a plant cell-derived extrahaustorial membrane (EHM). Over the EHM, the fungus obtains nutrients from and secretes effector proteins into the plant cell. In the plant cell these effectors interfere with cellular processes such as pathogen defense and membrane trafficking. However, the mechanisms behind effector delivery are largely unknown. This paper provides a model for and new insights into a putative transfer mechanism of effectors into the plant cell. We show that silencing of the barley Sec61βa transcript results in decreased susceptibility to the powdery mildew fungus. HvSec61βa is a component of both the endoplasmic reticulum (ER) translocon and retrotranslocon pores, the latter being part of the ER-associated protein degradation machinery. We provide support for a model suggesting that the retrotranslocon function of HvSec61βa is required for successful powdery mildew fungal infection. HvSec61βa-GFP and a luminal ER marker were co-localized to the ER, which was found to be in close proximity to the EHM around the haustorial body, but not the haustorial fingers. This differential EHM proximity suggests that the ER, including HvSec61βa, may be actively recruited by the haustorium, potentially to provide efficient effector transfer to the cytosol. Effector transport across this EHM-ER interface may occur by a vesicle-mediated process, while the Sec61 retrotranslocon pore potentially provides an escape route for these proteins to reach the cytosol.

[Synergistic apoptotic effect of the combination of diosgenin and TRAIL on non-small-cell lung cancer cell line A549 evaluated with the Chou-Talalay method]

This study is to investigate the apoptotic induction effect of the combination of diosgenin and TNF-related apoptosis-inducing ligand (TRAIL) on non-small-cell lung cancer cell line A549 by using the Chou-Talalay method, and observe the mechanism of the combination. The apoptotic effect of diosgenin or TRAIL alone and their combination on A549 and normal cell line 293T proliferation was measured by MTT assay. Chou-Talalay method was used to evaluate the combination effect. Apoptosis was examined by Hoechst 33342 staining and flow cytometry assay. Western blotting detects the expression of apoptosis-associated proteins. Diosgenin or TRAIL alone can inhibit proliferation ofA549 in a concentration-dependent manner. According to the Chou-Talalay method, when f(a) = 0.1, CI > 1, when f(a) > 0.1, CI < 1. Combined with TRAIL, the IC50 of diosgenin decreases from 21.864 to 14.810 micromol x L(-1) (P < 0.05) on A549 cells. But for 293T cells, IC50 of diosgenin does not change significantly. As with Hoechst 33342 staining and flow cytometry assay, the apoptosis ratios also increased in the combination group. At protein expression level, combination-treated group displays increased Caspase-8, Caspase-9, Bid, Caspase-3 activation and PARP cleavage, significantly decreased Bcl-2 and increased Bax expression, and MAPK pathways were activated. The combination of diosgenin and TRAIL has synergistic effect on A549 cells.

[Residual levels of pesticides in freshwater fish from Beijing aquatic product markets and health risk assessment]

Health risks by fish consumption were assessed following the investigation of the residual levels of 25 pesticides in four kinds of freshwater fish from 4 aquatic product markets in Beijing using ultrasonic extraction-GC-MS. Eighteen pesticides were detected from the 48 samples collected. Acetochlor (97.9%) and beta-HCH (93.8%) showed high detection rates. The pesticide detected in highest concentration was chlorothalonil (1 779.4 microg x kg(-1)), followed by deltamethrin (620.3 microg x kg(-1)). Coexistence of 2-10 kinds of pesticides in fish was found with the total pesticide concentration in range of 2.7-1932 microg x kg(-1). Based on the averaged fish consumption of Beijing residents, the health risk of the studied pesticides by freshwater fish consumption was calculated as 0.043 43, suggesting a relatively low health risk.

Triptolide with potential medicinal value for diseases of the central nervous system

Tripterygium wilfordii Hook.f. (TWHF) has a long history as a Traditional Chinese Medicine (TCM) herb that aids in treating inflammatory and autoimmune diseases. The major bioactive component of TWHF is triptolide, which has been recognized to possess a broad spectrum of biological profiles including antiinflammatory, immunosuppressive, antifertility, and antitumor activities, as well as neurotrophic and neuroprotective effects. Limitation of triptolide, such as poor water solubility and severe systemic toxicity, has postponed clinical development and trials; however, the wide range of medicinal value of triptolide has been drawing intensive worldwide attention. In particular, triptolide has been shown to have significant effects on central nervous system (CNS) diseases, such as Parkinson's disease, Alzheimer's disease, spinal cord and brain injury, and multiple sclerosis. This review focuses on the potential therapeutic role of triptolide on CNS diseases, and discusses the structural features, potential modifications, and the other pharmacological activities of triptolide.