Human peripheral blood monuclear cells transfected with messenger RNA stimulate antigen-specific cytotoxic T-lymphocytes in vitro

The efficiency of test vaccines needs to be evaluated by quantification of the triggered cellular immune response. Usually, for these assays, autologous target cells expressing the vaccine antigen are required. In the context of messenger RNA (mRNA)-based vaccinations, the target cells used for the read-out are mRNA-transfected monocyte-derived dendritic cells (Mo-DCs). Their production typically requires samples of 100 ml blood from the patients, and limits the number of assays that can be performed. We show here that fresh peripheral blood mononuclear cells (PBMCs) can be transfected with mRNA by electroporation. Such cells are as efficient as mRNA-transfected Mo-DCs for their ability to activate memory T cells in vitro. Thus, mRNA-transfected PBMCs are a convenient replacement of mRNA-transfected Mo-DCs for the in vitro monitoring of natural or vaccine-induced immune responses.Received 17 February 2005; received after revision 1 May 2005; accepted 7 Juni 2005     

Recent advances in hydrogen storage technologies based on nanoporous carbon materials

Hydrogen is a promising energy carrier that can potentially facilitate a transition from fossil fuels to sustainable energy sources without producing harmful by-products. Prior to realizing a hydrogen economy, however, viable hydrogen storage materials must be developed. Physical adsorption in porous solids provides an opportunity for hydrogen storage under low-stringency conditions. Physically adsorbed hydrogen molecules are weakly bound to a surface and, hence, are easily released. Among the various surface candidates, porous carbons appear to provide efficient hydrogen storage, with the advantages that porous carbon is relatively low-cost to produce and is easily prepared. In this review, we summarize the preparation methods, pore characteristics, and hydrogen storage capacities of representative nanoporous carbons, including activated carbons, zeolite-templated carbon, and carbide-derived carbon. We focus particularly on a series of nanoporous carbons developed recently: metal–organic framework-derived carbons, which exhibit promising properties for use in hydrogen storage applications.     

Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses

The innate immune system senses viral infection by recognizing a variety of viral components (including double-stranded (ds)RNA) and triggers antiviral responses. The cytoplasmic helicase proteins RIG-I (retinoic-acid-inducible protein I, also known as Ddx58) and MDA5 (melanoma-differentiation-associated gene 5, also known as Ifih1 or Helicard) have been implicated in viral dsRNA recognition. In vitro studies suggest that both RIG-I and MDA5 detect RNA viruses and polyinosine-polycytidylic acid (poly(I:C)), a synthetic dsRNA analogue. Although a critical role for RIG-I in the recognition of several RNA viruses has been clarified, the functional role of MDA5 and the relationship between these dsRNA detectors in vivo are yet to be determined. Here we use mice deficient in MDA5 (MDA5-/-) to show that MDA5 and RIG-I recognize different types of dsRNAs: MDA5 recognizes poly(I:C), and RIG-I detects in vitro transcribed dsRNAs. RNA viruses are also differentially recognized by RIG-I and MDA5. We find that RIG-I is essential for the production of interferons in response to RNA viruses including paramyxoviruses, influenza virus and Japanese encephalitis virus, whereas MDA5 is critical for picornavirus detection. Furthermore, RIG-I-/- and MDA5-/- mice are highly susceptible to infection with these respective RNA viruses compared to control mice. Together, our data show that RIG-I and MDA5 distinguish different RNA viruses and are critical for host antiviral responses.     

红假单胞菌R18二氧化碳固定基因的序列测定及其表达

在红假单胞菌Ｒ１８质粒的限制性酶切基础上,建立了该质粒的物理图谱;采用ｄｙｅ ｐｒｉｍｅｒ法测定了Ｒ１８ ＲｕｂｉｓＣＯ基因的部分核酸序列;以ＰＢＲ３２２为载体,将Ｒ１８ ＲｕｂｉｓＣＯ基因转入紫色非硫杆菌Ｒｈｏｄｏｐｓｅｕｄｏｍｏｎａ．ｐａｌｕｓｔｒｉｓ Ｎｏ．７的野生菌及其ＲｕｂｉｓＣＯ ＦｏｒｍＩ缺陷型中,获得的转化子ＭＧ１１和ＭＧ１４的ＲｕｂｉｓＣＯ酶活性分别是其受体菌的１．７７倍和７．１     

Crystal structure of the ligand-free G-protein-coupled receptor opsin

In the G-protein-coupled receptor (GPCR) rhodopsin, the inactivating ligand 11-cis-retinal is bound in the seven-transmembrane helix (TM) bundle and is cis/trans isomerized by light to form active metarhodopsin II. With metarhodopsin II decay, all-trans-retinal is released, and opsin is reloaded with new 11-cis-retinal. Here we present the crystal structure of ligand-free native opsin from bovine retinal rod cells at 2.9 ?ngstr?m (A) resolution. Compared to rhodopsin, opsin shows prominent structural changes in the conserved E(D)RY and NPxxY(x)(5,6)F regions and in TM5-TM7. At the cytoplasmic side, TM6 is tilted outwards by 6-7 A, whereas the helix structure of TM5 is more elongated and close to TM6. These structural changes, some of which were attributed to an active GPCR state, reorganize the empty retinal-binding pocket to disclose two openings that may serve the entry and exit of retinal. The opsin structure sheds new light on ligand binding to GPCRs and on GPCR activation.     

Control of plant germline proliferation by SCF(FBL17) degradation of cell cycle inhibitors

Flowering plants possess a unique reproductive strategy, involving double fertilization by twin sperm cells. Unlike animal germ lines, the male germ cell lineage in plants only forms after meiosis and involves asymmetric division of haploid microspores, to produce a large, non-germline vegetative cell and a germ cell that undergoes one further division to produce the twin sperm cells. Although this switch in cell cycle control is critical for sperm cell production and delivery, the underlying molecular mechanisms are unknown. Here we identify a novel F-box protein of Arabidopsis thaliana, designated FBL17 (F-box-like 17), that enables this switch by targeting the degradation of cyclin-dependent kinase A;1 inhibitors specifically in male germ cells. We show that FBL17 is transiently expressed in the male germ line after asymmetric division and forms an SKP1-Cullin1-F-box protein (SCF) E3 ubiquitin ligase complex (SCF(FBL17)) that targets the cyclin-dependent kinase inhibitors KRP6 and KRP7 for proteasome-dependent degradation. Accordingly, the loss of FBL17 function leads to the stabilization of KRP6 and inhibition of germ cell cycle progression. Our results identify SCF(FBL17) as an essential male germ cell proliferation complex that promotes twin sperm cell production and double fertilization in flowering plants.     

Proline-catalysed Mannich reactions of acetaldehyde

Small organic molecules recently emerged as a third class of broadly useful asymmetric catalysts that direct reactions to yield predominantly one chiral product, complementing enzymes and metal complexes. For instance, the amino acid proline and its derivatives are useful for the catalytic activation of carbonyl compounds via nucleophilic enamine intermediates. Several important carbon-carbon bond-forming reactions, including the Mannich reaction, have been developed using this approach, all of which are useful for making chiral, biologically relevant compounds. Remarkably, despite attempts, the simplest of all nucleophiles, acetaldehyde, could not be used in this way. Here we show that acetaldehyde is a powerful nucleophile in asymmetric, proline-catalysed Mannich reactions with N-tert-butoxycarbonyl (N-Boc)-imines, yielding beta-amino aldehydes with extremely high enantioselectivities-desirable products as drug intermediates and in the synthesis of other biologically active molecules. Although acetaldehyde has been used as a nucleophile in reactions with biological catalysts such as aldolases and thiamine-dependent enzymes, and has also been employed indirectly, its use as an inexpensive and versatile two-carbon nucleophile in asymmetric, small-molecule catalysis will find many practical applications.     

Simple nanofabrication of a superhydrophobic and transparent biomimetic surface

This paper describes a simple fabrication method for creating superhydrophobic and transparent glass surfaces that mimic natural surfaces such as lotus leaves, moth eyes or cicada wings. Nanostructured glass surfaces were created by a combination of colloidal lithography and plasma etching. A colloidal mask was formed simply by the spin coating of the polystyrene beads and with modification of the interparticle distance between the beads. The etching of the glasses was conducted by CF4 plasma. Tower-shaped nanostructures at an aspect ratio of 1：4 were treated using fluoroalkylsilane selfassembled monolayers （SAMs） to obtain the hydrophobic surfaces. The treated glass surfaces showed superhydrophobicity with a water contact angle of around 150° and a hexadecane contact angle of around 110° Furthermore, the nanostructured glass was transparent to visible light.     

On the association between IPO underpricing and reversal and Taiwan's regulatory reforms for mandatory forecasts

The unique institutions in Taiwan may add to our understanding of the effect of initial public offering (IPO) firm disclosures. Consistent with the notion of market mispricing, most of Taiwan's IPOs were with consecutive up‐limit hits followed by substantial price reversals. In this study, we decompose IPO underpricing into two components: pure underpricing and subsequent reversal, exploring the impact of the 1991 mandate that IPO firms should include their management forecasts in the prospectuses on these two anomaly measures. Our results support the notion that disclosure regulations ameliorate investors' mispricing the stocks. First, pure underpricing and reversal are significantly less (more) pronounced for post‐mandate (pre‐mandate) IPO stocks. In contrast, consistent with the cheap talk hypothesis, the pre‐mandate voluntary forecasters (non‐forecasters) appear to be more (less) underpriced. Second, the duration of underpricing for the post‐mandate (pre‐mandate) IPOs appears to be shorter (longer). Nevertheless, underpricing lasted relatively longer (shorter) for the pre‐mandate IPOs with (with no) voluntary disclosures. Copyright © 2009 John Wiley & Sons, Ltd.