An Ethnohistorical Dictionary of China

An Ethnohistorical Dictionary of China. James S. Olson. Westport, CT: Greenwood Press, 1998. 422 pp.     

Functional genomic analysis of Arabidopsis thaliana glycoside hydrolase family 35

Catalysing the hydrolysis of terminal beta-galactosyl residues from carbohydrates, galactolipids, and glycoproteins, glycoside hydrolase family 35 (beta-galactosidases; BGALs) are widely distributed in plants and believed to play many key roles, including modification of cell wall components. Completion of the Arabidopsis thaliana genome sequencing project has, for the first time, allowed an examination of the total number, gene structure, and evolutionary patterns of all Family 35 members in a representative (model) angiosperm. Reiterative database searches established a multigene family of 17 members (designated BGAL1-BGAL17). Using these genes as query sequences, BLAST and Hidden Markov Model searches identified BGAL genes among 22 other eukaryotes, whose genomic sequences are known. The Arabidopsis (n=17) and rice (n=15) BGAL families were much larger than those of Chlamydomonas, fungi, and animals (n=0-4), and a lineage-specific expansion of BGAL genes apparently occurred after divergence of the Arabidopsis and rice lineages. All plant BGAL genes, with the exception of Arabidopsis BGAL17 and rice Os 9633.m04334, form a monophyletic group. Arabidopsis BGAL expression levels are much higher in mature leaves, roots, flowers, and siliques but are lower in young seedlings. BGAL8, BGAL11, BGAL13, BGAL14, and BGAL16 are expressed only in flowers. Catalytically active BGAL4 was produced in the E. coli and baculoviral expression systems, purified to electrophoretic homogeneity, and partially characterized. The purified enzyme hydrolyzed p- and o-nitrophenyl-beta-d-galactosides. It also cleaved beta-(1,3)-, beta-(1,4)-, and beta-(1,6)-linked galactobiosides and galactotriosides, showing a marked preference for beta-(1,3)- and beta-(1,4)-linkages.     

NADPH oxidase activity selectively modulates vascular endothelial growth factor signaling pathways

Vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS) play critical roles in vascular physiology and pathophysiology. We have demonstrated previously that NADPH oxidase-derived ROS are required for VEGF-mediated migration and proliferation of endothelial cells. The goal of this study was to determine the extent to which VEGF signaling is coupled to NADPH oxidase activity. Human umbilical vein endothelial cells and/or human coronary artery endothelial cells were transfected with short interfering RNA against the p47(phox) subunit of NADPH oxidase, treated in the absence or presence of VEGF, and assayed for signaling, gene expression, and function. We show that NADPH oxidase activity is required for VEGF activation of phosphoinositide 3-kinase-Akt-forkhead, and p38 MAPK, but not ERK1/2 or JNK. The permissive role of NADPH oxidase on phosphoinositide 3-kinase-Akt-forkhead signaling is mediated at post-VEGF receptor levels and involves the nonreceptor tyrosine kinase Src. DNA microarrays revealed the existence of two distinct classes of VEGF-responsive genes, one that is ROS-dependent and another that is independent of ROS levels. VEGF-induced, thrombomodulin-dependent activation of protein C was dependent on NADPH oxidase activity, whereas VEGF-induced decay-accelerating factor-mediated protection of endothelial cells against complement-mediated lysis was not. Taken together, these findings suggest that NADPH oxidase-derived ROS selectively modulate some but not all the effects of VEGF on endothelial cell phenotypes.     

Efficacy of curcumin therapy against Angiostrongylus cantonensis-induced eosinophilic meningitis

Angiostrongylus cantonensis can invade the central nervous system, leading to human eosinophilic meningitis or eosinophilic meningoencephalitis. Curcumin is a natural product which has the effects of anti-inflammation, anti-oxidation and anti-carcinogensis, while the administration of curcumin has been reported to possibly relieve the symptoms of meningitis. The present study tested the potential efficacy of curcumin in A. cantonensis-induced eosinophilic meningitis of BALB/c mice. Assay indicators for the therapeutic effect included the larvicidal effect, eosinophil counts and matrix metalloproteinase-9 (MMP-9) activity in angiostrongyliasis. Eosinophils were mildly reduced in treatment groups compared with infected-untreated mice. However, there were no significant differences in larvicidal effects or MMP-9 activity. This study suggests that anti-inflammatory treatment with curcumin alone has low efficacy, but the treatment does not interfere with MMP-9 expression and is not useful for larvicidal effects. The possible reasons include low curcumin across the blood-brain barrier and also those larvae that survive stimulate MMP-9 production, which promotes blood-brain barrier damage, with leukocytes then crossing the blood-brain barrier to cause meningitis. Further studies will be required to test these possibilities.     

Interaction between nicotine and MPTP/MPP+ in rat brain endothelial cells

To examine the interaction between nicotine and MPTP/MPP+ in the blood-brain barrier, cellular uptake of MPTP and MPP+ was studied in the presence of nicotine and several compounds, including MPTP/MPP+ analogs and a specific inhibitor of organic cation transporter (OCT) in an adult rat brain microvascular endothelial cell line (ARBEC). The kinetic properties of the uptake of MPTP, MPP+, and nicotine were also examined. In addition, a microdialysis study was performed to evaluate the in vivo effect of nicotine (i.p.) on extracellular levels of MPTP and MPP+ in the brain after intravenous administration of MPTP. The results showed that uptake of MPTP, MPP+, and nicotine was partly mediated by a carrier system that was sensitive to decynium22, a specific OCT inhibitor. RT-PCR showed the presence of OCT1 mRNA in ARBEC. Capacity for uptake of MPTP and nicotine was much higher than that for MPP+ (Km and Vm values of 10.94+/-1.44 microM and 0.049+/-0.007 pmol/mg s, respectively, for MPP+, compared to values of 35.75+/-0.85 microM and 40.95+/-3.56 pmol/mg s for MPTP and 25.29+/-6.44 microM and 51.15+/-14.18 pmol/mg s for nicotine). In addition, nicotine competitively inhibited the uptake of both MPTP and MPP+, with inhibition constants (Ki) of 328 microM and 210 microM, respectively. In vivo microdialysis results showed that nicotine significantly reduced brain extracellular levels of MPTP in the first 30 min (507.4+/-8.5 ng/ml vs. 637.9+/-30.8 ng/ml with and without nicotine pre-treatment, respectively), but did not have significant effect on those of MPP+. In conclusion, nicotine can inhibit in vitro cellular uptake and in vivo transfer of MPTP across the blood-brain barrier, which can be mediated by multiple pathways including OCT1.     

Phylogeny and phylogeography of the genus Geothelphusa (Crustacea: Decapoda, Brachyura, Potamidae) in southwestern Taiwan based on two mitochondrial genes

Eleven species of Geothelphusa have been reported from southwestern Taiwan (Tainan, Kaohsiung and the northern part of Pingtung counties): G. albogilva Shy, Ng, and Yu, 1994; G. ancylophallus Shy, Ng, and Yu, 1994; G. caesia Shy, Ng, and Yu, 1994; G. lili Chen, Cheng, and Shy, 2005; G. nanhsi Shy, Ng, and Yu, 1994; G. neipu Chen, Cheng, and Shy, 1998; G. olea Shy, Ng, and Yu, 1994; G. pingtung Tan and Liu, 1998; G. shernshan Chen, Cheng, and Shy, 2005; G. tsayae Shy, Ng, and Yu, 1994 and G. wutai Shy, Ng, and Yu, 1994. Comparisons of DNA sequences encoding parts of the mitochondrial large subunit (16S) rRNA and cytochrome oxidase subunit I (COI) genes revealed three major clades, of which one is the species G. ancylophallus, and the other two are species groups here referred to as the G. olea and G. pingtung clades. Geothelphusa ancylophallus is geographically restricted and adapted to an ecologically challenging habitat with an unstable water supply and uneven topology. The G. olea clade (G. olea, G. caesia, G. nanhsi, G. tsayae, and G. wutai) is widely distributed throughout central-western and southwestern Taiwan. The G. pingtung clade (G. pingtung, G. neipu and G. shernshan) is confined to southwestern Taiwan between the previously defined southernmost clades of G. tawu, G. albogilva, and G. ferruginea, and the G. olea clade to the north. It includes an isolated population on distant Chaishan Mountain near Taiwan Strait, which probably dispersed from the peripheral hills of the Central Range during the early Pleistocene. The available genetic evidence indicates that the differential coloration observed in members of the G. olea and G. pingtung clades is not reflected in mtDNA, appears to be dependent on environmental conditions, food, etc., and has little value as a taxonomic character. Possible geological events and climatic factors responsible for the historic isolation of the different freshwater crab clades in southwestern Taiwan are discussed in detail.     

Polar positional information in Escherichia coli spherical cells

Shigella surface protein IcsA and its cytoplasmic derivatives are localized to the old pole of rod-shaped cells when expressed in Escherichia coli. In spherical mreB cells, IcsA is targeted to ectopic sites and close to one extremity of actin-like MamK filament. To gain insight into the properties of the sites containing polar material, we studied the IcsA localization in spherical cells. GFP was exported into the periplasm via the Tat pathway and used as a periplasmic space marker. GFP displayed zonal fluorescence in both mreB and rodA-pbpA spherical E. coli cells, indicating an uneven periplasmic space. Deconvolution images revealed that the cytoplasmic IcsA fused to mCherry was localized outside or at the edge of the GFP zones. These observations strongly suggest that polar material is restricted to the positions where the periplasm possesses particular structural or biochemical properties.     

Green tea catechin inhibits ephrin-A1-mediated cell migration and angiogenesis of human umbilical vein endothelial cells

Angiogenesis, the formation of new blood vessels from preexisting capillaries, is essential for tumor progression and metastasis. During tumor neovascularization, vascular endothelial growth factor and ephrin (Eph) families emerge as critical mediators of angiogenesis. The green tea catechin epigallocatechin gallate (EGCG), a tyrosine kinase inhibitor, has been demonstrated in previous studies to be an effective antiangiogenesis agent. However, the inhibitory effect of green tea catechins on ephrin-A1-mediated tumor angiogenesis has not been demonstrated yet. Thus, in this study, we investigated the molecular mechanism of ephrin-A1-mediated cell migration and angiogenesis, as well as the inhibitory effects of EGCG. Here we show that ephrin-A1 mediates endothelial cell migration and regulates vascular remodeling in tumor neovascularization in vitro. We also demonstrated that ephrin-A1-mediated cell migration required the activation of extracellular-regulated kinase (ERK-1/2) but not of phosphatidylinositol-3-kinase. The green tea catechin EGCG inhibited ephrin-A1-mediated endothelial cell migration, as well as tumor angiogenesis, in a dose-dependent manner. Furthermore, EGCG inhibited the ephrin-A1-mediated phosphorylation of EphA2 and ERK-1/2. Taken together, these data indicated that activation of ERK-1/2 plays an essential role in ephrin-A1-mediated cell migration. EGCG inhibited ephrin-A1-mediated endothelial migration and angiogenesis. It suggests a novel antiangiogenesis application of EGCG in cancer chemoprevention.     

The type 2 dengue virus envelope protein interacts with small ubiquitin-like modifier-1 (SUMO-1) conjugating enzyme 9 (Ubc9)

Dengue viruses are mosquito-borne flaviviruses and may cause the life-threatening dengue hemorrhagic fever and dengue shock syndrome. Its envelope protein is responsible mainly for the virus attachment and entry to host cells. To identify the human cellular proteins interacting with the envelope protein of dengue virus serotype 2 inside host cells, we have performed a screening with the yeast-two-hybrid-based “Functional Yeast Array”. Interestingly, the small ubiquitin-like modifier-1 conjugating enzyme 9 protein, modulating cellular processes such as those regulating signal transduction and cell growth, was one of the candidates interacting with the dengue virus envelope protein. With co-precipitation assay, we have demonstrated that it indeed could interact directly with the Ubc9 protein. Site-directed mutagenesis has demonstrated that Ubc9 might interact with the E protein via amino acid residues K51 and K241. Furthermore, immunofluorescence microscopy has shown that the DV2E-EGFP proteins tended to progress toward the nuclear membrane and co-localized with Flag-Ubc9 proteins around the nuclear membrane in the cytoplasmic side, and DV2E-EGFP also shifted the distribution of Flag-Ubc9 from evenly in the nucleus toward concentrating around the nuclear membrane in the nucleic side. In addition, over-expression of Ubc9 could reduce the plaque formation of the dengue virus in mammalian cells. This is the first report that DV envelope proteins can interact with the protein of sumoylation system and Ubc9 may involve in the host defense system to prevent virus propagation.