Regional and seasonal variability of zooplankton collected using sediment traps in the southeastern Beaufort Sea, Canadian Arctic

Time-series sediment traps were deployed at six mooring sites in the southeastern Beaufort Sea from October 2003 to August 2004 during the cruise of the Canadian research vessel Amundsen within the framework of the Canadian Arctic Shelf Exchange Study (CASES). Trap-collected zooplankton (TCZ) at around 200 m water depth was dominated by copepods accounting for 74–93% of the total abundance throughout the year with increase in abundance at all sites during the fall. Seven distinct TCZ groups were identified through cluster analysis. Two marked seasonal shifts in TCZ composition from late fall to early winter and from spring to early summer were revealed at five sites at 200 m depth. The zooplankton was dominated by Oncaea spp., pteropods, and copepod nauplii in the late fall cluster and in the winter cluster, and by copepod nauplii in the summer cluster. A significant change in water temperature, salinity, and sea ice concentration was observed only with the spring–summer shift. The cluster analysis also revealed that TCZ composition at 200 m at a station located in the Cape Bathurst Polynya was markedly different from those at other sites through the study period by being characterized by the dominance of various copepodite stages of Metridia longa. This was probably due to a less prolonged period of sea ice cover, which provides favorable food conditions for the zooplankton community.     

IL-17A suppresses the expression of bone resorption-related proteinases and osteoclast differentiation via IL-17RA or IL-17RC receptors in RAW264.7 cells

Interleukin-17 (IL-17) is produced exclusively by activated T cells and neutrophils, and stimulates osteoclastic bone resorption via osteoblasts by inducing the expression of “receptor activator of NF-κB (RANK) ligand” (RANKL). However, the direct effects of IL-17 on the differentiation of osteoclast precursors into osteoclasts and on the function of osteoclasts have not been clarified. Therefore, we examined the effects of IL-17A on the differentiation of osteoclast precursors using RAW264.7 cells and also on the expression of carbonic anhydrase II (CA II), cathepsin K, matrix metalloproteinases-9 (MMP-9), RANK, c-fms, and IL-17 receptors in these cells. The cells were cultured with or without 0.1, 1.0, 10 or 50 ng/mL IL-17 in the presence of soluble RANKL for up to 10 days. The CA II, cathepsin K, and MMP-9 mRNA and protein expression levels were examined using real-time PCR and Western blotting, respectively. The mRNA expression levels of RANK, c-fms, and IL-17 receptors were monitored by real-time PCR. Osteoclast differentiation was estimated using tartrate-resistant acid phosphatase (TRAP) staining of the cells. TRAP-positive cells were observed after day 5 of culture, and the number of cells decreased in the presence of 10 and 50 ng/mL IL-17A at days 5 and 7. In the presence of IL-17A, the expressions of cathepsin K, MMP-9 and c-fms decreased markedly on days 5 and/or 7 of culture, whereas the expression of CA II and IL-17 receptor (type A) increased remarkably at days 3 and 7, respectively. The expression of RANK and IL-17 receptor (type C) was not affected by the addition of IL-17A. These results suggest that the differentiation of osteoclast precursors into osteoclasts is suppressed at high concentrations of IL-17A. Furthermore, IL-17A suppresses the hydrolysis of matrix proteins during bone resorption by decreasing the production of cathepsin K and MMP-9 in osteoclasts.     

Tellimagrandin I,HCV invasion inhibitor from Rosae Rugosae Flos

By use of the model virus, expressing the HCV envelope proteins E1 and E2, bioassay guided separation of the MeOH extract from Rosa rugosa Thunb. disclosed tellimagrandin I (1) together with eugeniin (2) and casuarictin (3) as the potent HCV invasion inhibitors. Furthermore, structure–activity relationship analysis of some relative tannins including the synthesized analogs elucidated the partial structures crucial for potent activity of 1.     

Efficient microwave-assisted prenylation of pinostrobin and biological evaluation of its derivatives as antitumor agents

Pinostrobin (5-hydroxy-7-methoxyflavanone) obtained in relatively large amounts from fingerroot (Boesenbergia pandurata) was converted to its C-6 and C-8 prenylated derivatives. The Mitsunobu reaction, europium(III)-catalyzed Claisen–Cope rearrangement, and Claisen reaction coupled with cross-metathesis were used as the key steps. Using a sealed-vessel microwave reactor, the Mitsunobu and Claisen/Cope reactions occurred smoothly with short reaction times and in satisfactory yields. The target compounds and five new intermediary substances showed cytotoxic activity toward SK-BR-3, MCF-7, PC-3, and Colo-320DM human tumor cell lines, and all of them had significantly lower IC₅₀ (μM) values than pinostrobin.     

Iodidimonas gelatinilytica sp. nov., aerobic iodide-oxidizing bacteria isolated from brine water and surface seawater

Antonie van Leeuwenhoek - Chemo-organotrophic iodide (I?)-oxidizing bacterial strains Hi-2T and Mie-1 were isolated from iodide-rich natural gas brine water in Chiba and surface seawater in...     

Human-Derived Physiological Heat Shock Protein 27 Complex Protects Brain after Focal Cerebral Ischemia in Mice

Although challenging, neuroprotective therapies for ischemic stroke remain an interesting strategy for countering ischemic injury and suppressing brain tissue damage. Among potential neuroprotective molecules, heat shock protein 27 (HSP27) is a strong cell death suppressor. To assess the neuroprotective effects of HSP27 in a mouse model of transient middle cerebral artery occlusion, we purified a “physiological” HSP27 (hHSP27) from normal human lymphocytes. hHSP27 differed from recombinant HSP27 in that it formed dimeric, tetrameric, and multimeric complexes, was phosphorylated, and contained small amounts of αβ-crystallin and HSP20. Mice received intravenous injections of hHSP27 following focal cerebral ischemia. Infarct volume, neurological deficit scores, physiological parameters, and immunohistochemical analyses were evaluated 24 h after reperfusion. Intravenous injections of hHSP27 1 h after reperfusion significantly reduced infarct size and improved neurological deficits. Injected hHSP27 was localized in neurons on the ischemic side of the brain. hHSP27 suppressed neuronal cell death resulting from cytochrome c-mediated caspase activation, oxidative stress, and inflammatory responses. Recombinant HSP27 (rHSP27), which was artificially expressed and purified from Escherichia coli, and dephosphorylated hHSP27 did not have brain protective effects, suggesting that the phosphorylation of hHSP27 may be important for neuroprotection after ischemic insults. The present study suggests that hHSP27 with posttranslational modifications provided neuroprotection against ischemia/reperfusion injury and that the protection was mediated through the inhibition of apoptosis, oxidative stress, and inflammation. Intravenously injected human HSP27 should be explored for the treatment of acute ischemic strokes.     

NMR spectroscopic characterization of a model RNA duplex reflecting the core sequence of hammerhead ribozymes

ABSTRACT

Hammerhead ribozymes are a model system for studying molecular mechanism of RNA catalysis. Physicochemical data-driven mechanistic studies are an indispensable step towards understanding the catalysis of hammerhead ribozymes. Here we characterized a model RNA duplex with catalytically important sheared-type G12-A9 base pair and A9-G10.1 metal ion-binding motif in hammerhead ribozymes. By using high magnetic field NMR, all base proton signals, including catalytic residues, were unambiguously assigned. We further characterized structural features of this RNA molecule and found that it reflects the structural features of the A9-G10.1 motif of hammerhead ribozymes. Therefore, this RNA molecule is suitable for extracting an intrinsic physicochemical properties of catalytically important residues.