Cleavage of oligonucleotides containing a P3'→N5' phosphoramidate linkage mediated by single-stranded oligonucleotide templates

Double-stranded DNA (dsDNA) templates can hybridize to and accelerate cleavage of oligonucleotides containing a P3'→N5' phosphoramidate (P-N) linkage. This dsDNA-templated cleavage of P-N linkages could be due to conformational strain placed on the linkage upon triplex formation. To determine whether duplex formation also induced conformational strain, we examined the reactivity of the oligonucleotides with a P-N linkage in the presence of single-stranded templates, and compared these reactions to those with dsDNA templates. P-N oligonucleotides that are cleaved upon duplex formation could be used as probes to detect single-stranded nucleic acids.     

Reversible deprotonation and protonation behaviors of a tetra-protonated γ-Keggin silicodecatungstate

The potentiometric titration of a γ-Keggin tetra-protonated silicodecatungstate, [γ-SiW(10)O(34)(H(2)O)(2)](4-) (H(4)·I), with TBAOH (TBA = [(n-C(4)H(9))(4)N](+)) showed inflection points at 2 and 3 equiv of TBAOH. The (1)H, (29)Si, and (183)W NMR data suggested that the in situ formation of tri-, doubly-, and monoprotonated silicodecatungstates, [γ-SiW(10)O(34)(OH)(OH(2))](5-) (H(3)·I), [γ-SiW(10)O(34)(OH)(2)](6-) (H(2)·I), and [γ-SiW(10)O(35)(OH)](7-) (H·I), with C(1), C(2v), and C(2) symmetries, respectively. Single crystals of TBA(6)·H(2)·I suitable for the X-ray structure analysis were successfully obtained and the anion part was a monomeric γ-Keggin divacant silicodecatungstate with two protonated bridging oxygen atoms. Compounds H(3)·I, H(2)·I, and H·I were reversibly monoprotonated to form H(4)·I, H(3)·I, and H(2)·I, respectively.     

THz spectroscopy of H2D

The 2₁₂ − 1₁₁ line of H₂D⁺ at 2.363 THz that was detected toward Sgr B2 and identified based on a calculated line frequency has been measured in the laboratory precisely by using a tunable far-infrared spectrometer. All the available THz lines and known millimeter- and submillimeter-wave lines together with the combination differences derived from the infrared transitions are fitted to the Watson effective Hamiltonian. A set of improved molecular constants are obtained.     

Isolation, characterization and molecular evolution of a novel pearl shell lectin from a marine bivalve, Pteria penguin

Summary A novel lectin, PPL, was isolated from the mantle of penguin wing oyster (Pteria penguin) by affinity chromatography on mucin-Sepharose 4B and cation exchange chromatography on HiTrap SP. This lectin was estimated to be a 21-kDa monomer by gel filtration, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted time of flight (MALDI-TOF) mass spectrometry. However, dynamic light scattering experiments revealed that a non-covalently linked dimer formed under high salt conditions (500 mM NaCl). Interestingly, PPL showed an increasing hemagglutinating activity with increasing salt concentration. The amino acid sequence of PPL was determined by direct protein sequence analysis and cDNA cloning. The 167-amino acid sequence included 24 lysine residues and had two tandemly repeated homologous domains (residues 20–78 and 107–165) with 44% internal homology. PPL showed sequence homology to L-rhamnose-binding lectins from fish eggs and a D-galactose-binding lectin from sea urchin eggs, with sequence identities in the range 37–48%. PPL agglutinated various animal erythrocytes independently of calcium ions. The minimum concentration of PPL needed to agglutinate rabbit erythrocytes was 0.5 μg/ml, and the most effective saccharides to inhibit the hemagglutination were D-galactose, methyl-D-galactopyranoside and N-acetyl-D-lactosamine. Lactose also inhibited hemagglutination, but L-rhamnose did so only weakly despite the sequence homology with trout egg L-rhamnose-binding lectins. The carbohydrate-binding specificity of PPL was further examined by frontal affinity chromatography using 37 different pyridylaminated oligosaccharides. PPL was found to have strong binding affinity for various oligosaccharides that have Galβ1-4Glu/GlcNAc, Galβ1-3GalNAc/GlcNAc and Galα 1-4Gal moieties in their structure. PPL had a high thermal stability and retained 50% of its hemagglutinating activity after incubation at 70°C for 100 min. It agglutinated some Gram-negative bacteria by recognizing lipopolysaccharides. Together, these results suggest that PPL is a new member of the trout egg lectin family which participates in the self-defense mechanism against bacteria and pathogens with a distinct carbohydrate-binding specificity. We conclude that the trout egg lectin family proteins, in particular their carbohydrate recognition domains, have acquired diverse carbohydrate-binding specificities during molecular evolution.     

Synthesis of vertical-type bis(pyridodipyrimidines) as a redox catalyst and their autorecycling oxidation of alcohols

Condensation of bis(3-methyluracil-6-ylamino)alkanes with 6-chloro-5-formyl-3-methyluracil or 2,4,6-trichloropyrimidine-5-carbaldehyde in acetic acid gave the respective bis(pyridodipyrimidin-10-yl)alkanes (vertical-type bis(pyridodipyrimidines)). The vertical-type bis(pyridodipyrimidines) exhibited autorecycling turnover oxidation toward cyclopentanol and l-menthol to give the corresponding carbonyl compounds.     

Total synthesis of deglyco-bleomycin A2

Deglyco-bleomycin A2, the aglycon of bleomycin A2, has been synthesized for the first time.     

Consumer attitudes to radiation and irradiated potatoes at “radiation fair” in Osaka, Japan

“Radiation Fair” has been held in summer vacation season in August for more than 10 years in Osaka, the largest city of western Japan, for the purpose of public education and information transfer of radiation and radiation-related technology. We distributed questionnaires to the visitors for recent 3 years to inquire their status toward radiation and irradiated products including irradiated potatoes as well as impression toward the displays. According to the survey results, more than 60% of the kids visitors were satisfied with this exhibition as informative, more than half of the older visitors (16 years old and upward) indicated that they recognized the word of “radiation” when they were at elementary school and the most significant sources of this information were school lessons and the mass media. Consumer's image toward radiation seems to shift to more “positive” when correct knowledge about radiation is given. More than half of consumers did not know “irradiated potatoes” but the percentage indicating that irradiated potatoes was definitely hazardous was less than 10%.     

4-Ketoantheraxanthin, a novel carotenoid produced by the combination of the bacterial enzyme β-carotene ketolase CrtW and endogenous carotenoid biosynthetic enzymes in higher plants

Higher plants do not ordinarily possess ketocarotenoids due to the absence of a carotenoid ketolase enzyme. We expressed genes coding for marine-bacterial enzymes β-carotene ketolase (CrtW) and β-carotene hydroxylase (CrtZ) in tobacco plants (Nicotiana tabacum) by transplastomic engineering. A novel carotenoid, 4-ketoantheraxanthin, was isolated from the leaves of the tobacco transformants. The structure of 4-ketoantheraxanthin was determined to be (3S,3′S,5′R,6′S)-5′,6′-epoxy-3,3′-dihydroxy-β,β-caroten-4-one by analysis of the MS, NMR, and CD data. This carotenoid was considered to be synthesized by a 4-ketolation reaction by CrtW of antheraxanthin that had been synthesized by the endogenous carotenoid biosynthetic enzymes present in higher plants and CrtZ. 4-Ketoantheraxanthin was also shown to have potent antioxidative activity against a ¹O₂ suppression model.     

Electrokinetic analyte transport assay for alpha-fetoprotein immunoassay integrates mixing, reaction and separation on-chip

A rapid and highly sensitive CE immunoassay method integrating mixing, reaction, separation, and detection on-chip is described for the measurement of alpha-fetoprotein (AFP), a liver cancer marker in blood. Antibody-binding reagents, consisting of 245-bp DNA coupled anti-AFP WA1 antibody (DNA-WA1) and HiLyte dye-labeled anti-AFP WA2 antibody (HiLyte-WA2), and AFP-containing sample were filled into adjacent zones of a chip channel defined by the laminar flow lines of the microfluidic device using pressure-driven flow. The channel geometry was thus used to quantitatively aliquot the reagents and sample into the chip. DNA-WA1 was electrokinetically concentrated in the channel and sequentially transported through the AFP-sample zone and HiLyte-WA2 zone by ITP in such a manner that the AFP sandwich immune complex formation took place in the sample and HiLyte-WA2 zones. The sandwich AFP immune complex was then detected by LIF after CGE in a separation channel that was arranged downstream of the reaction channel. AFP was detected within 136 s with a detection sensitivity of 5 pM. The on-chip immunoassay described here, applying ITP concentration, in-channel reaction, and CGE separation, has the potential of providing a rapid and sensitive method for both clinical and research applications.