Identification of a radical SAM enzyme involved in the synthesis of archaeosine.

Archaeosine (G), 7-formamidino-7-deazaguanosine, is an archaea-specific modified nucleoside found at the 15th position of tRNAs. In Euryarchaeota, 7-cyano-7-deazaguanine (preQ)-containing tRNA (qN-tRNA), synthesized by archaeal tRNA-guanine transglycosylase (ArcTGT), has been believed to be converted to G-containing tRNA (G-tRNA) by the paralog of ArcTGT, ArcS. However, we found that several euryarchaeal ArcSs have lysine transfer activity to qN-tRNA to form qkN-tRNA, which has a preQ lysine adduct as a base.

A porous sintered material consisting of Presep PolyChelate as a chelating resin and particulate polyethylene as a thermoplastic binder for solid-phase extraction of trace elements.

Cylinder-type and disk-type sintered materials consisting of Presep PolyChelate, which is a commercially available chelating resin immobilizing carboxymethylated polyethyleneimine as a functional group, and particulate polyethylene as a thermoplastic binder were prepared using a polymer sintering technique. The sintered materials had a continuously porous structure. The sintering process at 130 °C for 20 min did not affect the ability of the chelating resin in the sintered materials; the selectivity of the sintered material was almost the same as that of the particulate chelating resin which was not sintered.

Determination of cadmium in water samples by liquid electrode plasma atomic emission spectrometry after solid phase extraction using a mini cartridge packed with chelate resin immobilizing carboxymethylated pentaethylenehexamine.

Solid phase extraction using a mini cartridge packed with 22 mg of chelate resin immobilizing carboxymethylated pentaethylenehexamine was successfully utilized for separation/preconcentration of cadmium in water samples prior to liquid electrode plasma atomic emission spectrometric (LEP-AES) determination. The combined method with the extraction and LEP-AES was applicable to the determination of cadmium in the certified reference materials (EU-L-1 wastewater and ES-L-1 groundwater); the detection limit was 0.20 microg in 200 mL of sample solution (500-fold preconcentration).