Norisoboldine,an Anti-Arthritis Alkaloid Isolated from Radix Linderae,Attenuates Osteoclast Differentiation and Inflammatory Bone Erosion in an Aryl Hydrocarbon Receptor-Dependent Manner

Norisoboldine (NOR), the primary isoquinoline alkaloid constituent of the root of Lindera aggregata, has previously been demonstrated to attenuate osteoclast (OC) differentiation. Accumulative evidence has shown that aryl hydrocarbon receptor (AhR) plays an important role in regulating the differentiation of various cells, and multiple isoquinoline alkaloids can modulate AhR. In the present study, we explored the role of NOR in the AhR signaling pathway. These data showed that the combination of AhR antagonist resveratrol (Res) or α-naphthoflavone (α-NF) nearly reversed the inhibition of OC differentiation through NOR. NOR could stably bind to AhR, up-regulate the nuclear translocation of AhR, and enhance the accumulation of the AhR-ARNT complex, AhR-mediated reporter gene activity and CYP1A1 expression in RAW 264.7 cells, suggesting that NOR might be an agonist of AhR. Moreover, NOR inhibited the nuclear translocation of NF-κB-p65, resulting in the evident accumulation of the AhR-NF-κB-p65 complex, which could be markedly inhibited through either Res or α-NF. Although NOR only slightly affected the expression of HIF-1α, NOR markedly reduced VEGF mRNA expression and ARNT-HIF-1α complex accumulation. In vivo studies indicated that NOR decreased the number of OCs and ameliorated the bone erosion in the joints of rats with collagen-induced arthritis, accompanied by the up-regulation of CYP1A1 and the down-regulation of VEGF mRNA expression in the synovium of rats. A combination of α-NF nearly completely reversed the effects of NOR. In conclusion, NOR attenuated OC differentiation and bone erosion through the activation of AhR and the subsequent inhibition of both NF-κB and HIF pathways.     

Analysis of fatty acids in A. szechenyianum Gay. by microwave‐assisted extraction and gas chromatography‐mass spectrometry

Introduction – Aconitum szechenyianum Gay. is a traditional Chinese medicinal herb with the detumescent and styptic effects and antitumor activity. There have been only a few researches on its chemical components, but no detailed report has appeared on its fatty acids. Objective – To develop a simple and effective method for the extraction of fatty acids from A. zechenyianum Gay. and then to investigate the fatty acid components. Methodology – Microwave‐assisted extraction (MAE) was optimized with response surface methodology, and the fatty acid compositions of extract were determined by GC–MS with previous derivatisation to fatty acid methyl esters (FAMEs). The results were compared with that obtained by classical Soxhlet extraction (SE). Results – Compared with SE, MAE showed significantly higher fatty acid yields, shorter extraction time, and lower energy and solvent consumption. The major fatty acids in A. szechenyianum Gay. are linoleic acid, palmitic acid, linolenic acid, oleic acid and stearic acid, and the unsaturated fatty acids occupy 66.4% of the total fatty acids. Copyright © 2010 John Wiley & Sons, Ltd.     

Carbon nanotube powders as electrode modifier to enhance the activity of anodic biofilm in microbial fuel cells

Carbon nanotube (CNT) is a promising electrode material and has been used as an anode modifier in microbial fuel cells (MFCs). In this study, a new method of simultaneously adding CNT powders and Geobacter sulfurreducens into the anode chamber of a MFC was used, aiming to form a composite biofilm on the anode. The performance of MFCs such as startup time and steady-state power generation was investigated under conditions of different CNT powders dosages. Results showed that both the startup time and the anodic resistance were reduced. The optimal dosage of CNT powders pre-treated by acid was 4 mg/mL for the anode chamber with an effective volume of 25 mL. The anodic resistance and output voltage of the MFC with CNT powders addition were maintained around 180 Ω and 650 mV during 40 days operation, while those of the MFC without CNT powders addition increased from 250 Ω to 540 Ω and decreased from 630 mV to 540 mV, respectively, demonstrating that adding CNT powders helped stabilize the anodic resistance, thus the internal resistance and power generation during long-term operation. Based on cyclic voltammogram, the electrochemical activity of anodic biofilm was enhanced by adding CNT powders, though no significant increase of the biomass in anodic biofilm was detected by phospholipids analysis. There was no remarkable change of ohmic resistance with an addition of CNT powders revealed by current interrupt method, which indicated that the rate of mass transfer might be promoted by the presence of CNT powders.     

Indication of intracellular physiological pH changes by L-cysteine-coated CdTe quantum dots with an acute alteration in emission color

A novel quantum dots (QDs) based biosensor was developed to monitor physiological pH changes in both fixed and living cells by means of pH-dependent emission color of the QDs. In our system, the nominally single-sized colloidal solution samples of the L-cysteine-capped CdTe QDs with intrinsically broadened size distributions were prepared by employing aqueous synthesis technique. The quench of fluorescence intensities of the QDs with a 16 nm red shift of the emission maximum and a color change from green to yellow was observed with a slight pH decrease (from 7.0 to 6.8) in the system. This pH-dependent emission could be attributed to the efficient exciton energy transfer from smaller QDs to larger ones, which was controlled by electrostatic-tuned aggregation/disaggregation (low/high pH values) processes of the QDs. In addition to high stability, the emission shift of the QDs was reversible for at least one cycle under optimal conditions. Our pH biosensor may find potential application for monitoring the intracellular pH changes in both physiological and pathological conditions.     

Heterologous expression of an endo-β-1,4-glucanase gene from the anaerobic fungus <Emphasis Type="Italic">Orpinomyces</Emphasis> PC-2 in <Emphasis Type="Italic">Trichoderma reesei</Emphasis>

The codon modified neutral endo-β-1,4-glucanase gene celEn, originating from the anaerobic fungus Orpinomyces sp. strain PC-2, was inserted between the strong promoter Pcel7A and the terminator Tcel7A from Trichoderma reesei. The resulting expression cassette was ligated to the pCAMBIA1300 Agrobacterium binary vector to construct pCB-hE that also contains a hygromycin B resistance marker. pCB-hE was introduced into T. reesei ZU-02 through an Agrobacterium tumefaciens–mediated transformation procedure that has been modified with an improved transformation efficiency of 12,500 transformants per 10⁷ conidia. Stable integration of the celEn gene into the chromosomal DNA of T. reesei ZU-02 was confirmed by PCR. After 48 h fermentation in shaking flasks, the endo-β-1,4-glucanase activities increased to 55–70 IU ml⁻¹ in transgenic strains, which were about 6–7 times higher than that of the original ZU-02 strain (9.5 IU ml⁻¹). When the avicel was added in fermentation medium, the endo-β-1,4-glucanase activity in the transgenic strains could be further increased to 193.6 IU ml⁻¹ after 84 h fermentation. Transgenic T. reesei strains with high neutral endo-β-1,4-glucanase activity will be particularly suitable for certain applications in textile industry. The improved procedures for overproduction and secretion of heterologous proteins in transgenic T. reesei can also be used to generate similar recombinant proteins for research or industrial purposes.     

Male gametophyte defective 4 encodes a rhamnogalacturonan II xylosyltransferase and is important for growth of pollen tubes and roots in Arabidopsis

In flowering plants, the growth of pollen tubes is essential for the delivery of sperm to the egg cells. Although many factors (including cell‐wall properties) are involved in this process, little is known about the underlying molecular mechanisms that regulate the growth of pollen tubes. We report here the characterization of an Arabidopsis mutant male gametophyte defective 4 (mgp4) that is severely defective in pollen tube growth. The mgp4 mutation also impairs root growth of pollen‐rescued mgp4 mutant plants generated by expressing MGP4 cDNA under the control of a pollen grain/tube‐specific promoter. The MGP4 gene encodes a putative xylosyltransferase and is expressed in many organs/tissues, including pollen tubes and roots. MGP4 protein expressed in Pichia pastoris exhibited xylosyltransferase activity and transferred d ‐xylose onto l ‐fucose. The pectic polysaccharide rhamnogalacturonan II (RG‐II), isolated from 7‐day‐old pollen‐rescued mutant seedlings, exhibited a 30% reduction in 2‐O‐methyl d ‐xylose residues. Furthermore, an exogenous supply of boric acid enhanced RG‐II dimer formation and partially restored the root growth of the pollen‐rescued mutant seedlings. Taken together, these results suggest that MGP4 plays important roles in pollen tube and root growth by acting as a xylosyltransferase involved in the biosynthesis of pectic RG‐II.