In this Letter we report the discovery of TeV gamma-ray emission from a supernova remnant made with the CANGAROO 3.8 m telescope. TeV gamma rays were detected at the sky position and extension coincident with the northeast rim of shell-type supernova remnant (SNR) SN 1006 (Type Ia). SN 1006 has been a most likely candidate for an extended TeV gamma-ray source, since the clear synchrotron X-ray emission from the rims was recently observed by ASCA (Koyama et al.), which is strong evidence for the existence of very high energy (up to hundreds of TeV) electrons in the SNR. The observed TeV gamma-ray flux was (2.4 ‫ע‬ 0.0.7 [systematic]) # 10 3.0 ‫ע‬ 0.9 (4.6 ‫ע‬ 0.6 ‫ע‬ 1.4) # 10 1.7 ‫ע‬ 0.5 from the 1996 and 1997 observations, respectively. Also, we set an upper limit on the TeV gamma-ray emission from the southwest rim, which is estimated to be cm Ϫ2 s Ϫ1 (≥ TeV, 95% confidence level) Ϫ12

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We have developed a new fluorescent sensing probe for double-stranded RNA (dsRNA) by integrating thiazole orange (TO) as a base surrogate into triplex-forming PNA. Our probe forms the thermally stable triplex with the target dsRNA at acidic pH; and the triplex formation is accompanied by the remarkable light-up response of the TO unit. The binding of our probe to the target dsRNA proceeds very rapidly, allowing real-time monitoring of the triplex formation. Importantly, we found the TO base surrogate in our probe functions as a universal base for the base pair opposite the TO unit in the triplex formation. Furthermore, the TO unit is significantly more responsive for the fully matched dsRNA sequence compared to the mismatch-containing sequences, which enables the analysis of the target dsRNA sequence at the single-base pair resolution. The binding and sensing functions of our probe are described for the development of fluorescent probes applicable to sensing biologically relevant dsRNA.

GPR34 is a G protein-coupled receptor belonging to the P2Y family. Here, we attempted to resolve conflicting reports about whether it is a functional lysophosphatidylserine (LysoPS) receptor. In HEK293 cells expressing human, mouse or rat GPR34 and Gα chimera between Gαq and Gαi1(Gq/i1), LysoPS quickly elevated intracellular Ca(2+) ion levels ([Ca(2+)](i)). LysoPS also stimulated alkaline phosphatase (AP)-tagged TGFα (AP-TGFα) release in GPR34-expressing HEK293 cells and induced the migration of CHO-K1 cells expressing GPR34. Other lysophospholipids did not induce these actions. Replacement of the serine residue of LysoPS abolished the reactivity of LysoPS with GPR34, indicating that GPR34 strictly recognizes the serine head group of LysoPS. Recombinant phosphatidylserine-specific phospholipase A(1) (PS-PLA(1)) that deacylates fatty acid at the sn-1 position of PS and produces 2-acyl-LysoPS, but not catalytically inactive mutant PS-PLA(1), stimulated the release of AP-TGFα from GPR34-expressing cells. Consistent with the result, LysoPS was detected in the cells treated with wild-type PS-PLA(1) but not with the mutant PS-PLA(1). PS treated with PLA(1) was much more effective at stimulating AP-TGFα release than PS treated with PLA(2). In addition, migration-resistant 2-acyl-1-deoxy-LysoPS, a 2-acyl-LysoPS analogue, was much more potent than 1-acyl-2-deoxy-LysoPS. The present studies confirm that GPR34 is a cellular receptor for LysoPS, especially with a fatty acid at the sn-2 position.