Measurement of trace I in natural water with ozone reaction for effective separation of spectral interferences.

Tandem quadrupole inductively coupled plasma mass spectrometry has the potential capability to measure I at extremely low concentration if spectral interferences from Xe and IH can be eliminated effectively. Ozone was introduced as the reaction gas, resulting significantly improved reactions of (I→IO) and (I→IO ), and permitted the highly sensitive measurement of I as IO and IO , helping eliminate spectral interferences related to Xe and IH . In isotopic ratio (I/I) analysis by measuring (I→IO )/(I→IO ), a blank ratio of 6.

On-line generated ozone as a reactive cell gas for tandem quadrupole inductively coupled plasma mass spectrometry.

On-line generated ozone was introduced as the cell gas of tandem quadrupole inductively coupled plasma mass spectrometry. Product ions of the ozone reaction showed that the formation of singly charged monoxide ions and dioxide ions was apparently improved for most elements, resulting in maximum improvement of the signal intensity by over 1000 times.

Computation of entropy values for non-electrolyte solute molecules in solution based on semi-empirical corrections to a polarized continuum model.

A simple heuristic model was developed for estimating the entropy of a solute molecule in an ideal solution based on quantum mechanical calculations with polarizable continuum models (QM/PCMs). A translational term was incorporated that included free-volume compensation for the Sackur-Tetrode equation and a rotational term was modeled based on the restricted rotation of a dipole in an electrostatic field. The configuration term for the solute at a given concentration was calculated using a simple lattice model that considered the number of configurations of the solute within the lattice.

Comparative Genome Analysis of Three Strains Used for Practical Production of Nata-de-Coco.

We determined the whole genome sequences of three bacterial strains, designated as FNDCR1, FNDCF1, and FNDCR2, isolated from a practical nata-de-coco producing bacterial culture. Only FNDCR1 and FNDCR2 strains had the ability to produce cellulose. The 16S rDNA sequence and phylogenetic analysis revealed that all strains belonged to the genus but belonged to a different clade within the genus.

Dietary intake and urinary excretion of methylated arsenicals of Japanese adults consuming marine foods and rice.

Dietary intake and urinary excretion of monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AsB) were measured in 150 adult Japanese subjects. Duplicate diet (DD) samples and first void of urine on the next morning of DD sampling day were collected and analysed for arsenic species with liquid chromatography-ICP mass spectrometry. Median (min-max) intakes of MMA, DMA and AsB were <2.

A Simplified Questionnaire for the Assessment of Inorganic Arsenic Intake in a Japanese Population.

A simplified questionnaire was developed to assess inorganic arsenic (iAs) intake level in a Japanese population. The two page questionnaire included photographs of single serving sizes of rice and cooked hijiki (: brown algae), and asked subjects about the number of servings of rice and cooked hijiki, two predominant dietary sources of iAs in Japan, they consume in a day. Daily intake of iAs was estimated for 72 Japanese subjects using the questionnaire together with data of iAs content in rice and hijiki seaweed, and the estimated intakes were compared with actual iAs intakes of the subjects as measured for a duplicate diet using liquid chromatography-inductively coupled plasma mass spectrometry.

Association of dietary intake and urinary excretion of inorganic arsenic in the Japanese subjects.

Quantitative relationship between intake of inorganic arsenic (iAs) and urinary excretion of iAs and its metabolite, methylarsonic acid (MMA), was investigated for 150 adult Japanese subjects. Duplicate diet was used for the determination of intake and first void of urine on the next day of duplicate diet sampling was used for urinary iAs + MMA determination. Speciation analysis of arsenic in diet and urine was carried out with liquid chromatography-inductively coupled plasma mass spectrometry.

A simple heuristic approach to estimate the thermochemistry of condensed-phase molecules based on the polarizable continuum model.

A simple model based on a quantum chemical approach with polarizable continuum models (PCMs) to provide reasonable translational and rotational entropies for liquid phase molecules was developed. A translational term was evaluated with free-volume compensation for the Sackur-Tetrode equation. We assumed that the free-volume corresponds to the cavity volume in the PCM.

Production of acetoin from hydrothermally pretreated oil mesocarp fiber using metabolically engineered Escherichia coli in a bioreactor system.

Acetoin is used in the biochemical, chemical and pharmaceutical industries. Several effective methods for acetoin production from petroleum-based substrates have been developed, but they all have an environmental impact and do not meet sustainability criteria. Here we describe a simple and efficient method for acetoin production from oil palm mesocarp fiber hydrolysate using engineered Escherichia coli.

Draft Genome Sequence of Burkholderia sp. Strain CCA53, Isolated from Leaf Soil.

Burkholderia sp. strain CCA53 was isolated from leaf soil collected in Higashi-Hiroshima City in Hiroshima Prefecture, Japan. Here, we present a draft genome sequence of this strain, which consists of a total of 4 contigs containing 6,647,893 bp, with a G+C content of 67.

Isolation and characterization of Burkholderia sp. strain CCA53 exhibiting ligninolytic potential.

Microbial degradation of lignin releases fermentable sugars, effective utilization of which could support biofuel production from lignocellulosic biomass. In the present study, a lignin-degrading bacterium was isolated from leaf soil and identified as Burkholderia sp. based on 16S rRNA gene sequencing.

Molecular cloning and characterization of two YGL039w genes encoding broad specificity NADPH-dependent aldehyde reductases from Kluyveromyces marxianus strain DMB1.

Two genes from Kluyveromyces marxianus strain DMB1, YGL039w1 and YGL039w2, encode putative uncharacterized oxidoreductases that respectively share 42 and 44% identity with the Saccharomyces cerevisiae S288c NADPH-dependent methylglyoxal reductase (EC 1.1.1.

Characterization of the Kluyveromyces marxianus strain DMB1 YGL157w gene product as a broad specificity NADPH-dependent aldehyde reductase.

The open reading frame YGL157w in the genome of the yeast Kluyveromyces marxianus strain DMB1 encodes a putative uncharacterized oxidoreductase. However, this protein shows 46% identity with the Saccharomyces cerevisiae S288c NADPH-dependent methylglyoxal reductase, which exhibits broad substrate specificity for aldehydes. In the present study, the YGL157w gene product (KmGRE2) was purified to homogeneity from overexpressing Escherichia coli cells and found to be a monomer.

Bacterial production of isobutanol without expensive reagents.

Isobutanol is attracting attention as a potential biofuel because it has higher energy density and lower hygroscopicity than ethanol. To date, several effective methods for microbial production of isobutanol have been developed, but they require expensive reagents to maintain expression plasmids and induce expression, which is not suitable for practical production. Here, we describe a simple and efficient method for isobutanol production in Escherichia coli.

Structures and functions of Qβ replicase: translation factors beyond protein synthesis.

Qβ replicase is a unique RNA polymerase complex, comprising Qβ virus-encoded RNA-dependent RNA polymerase (the catalytic β-subunit) and three host-derived factors: translational elongation factor (EF) -Tu, EF-Ts and ribosomal protein S1. For almost fifty years, since the isolation of Qβ replicase, there have been several unsolved, important questions about the mechanism of RNA polymerization by Qβ replicase. Especially, the detailed functions of the host factors, EF-Tu, EF-Ts, and S1, in Qβ replicase, which are all essential in the Escherichia coli (E.

Establishment of a novel gene expression method, BICES (biomass-inducible chromosome-based expression system), and its application to the production of 2,3-butanediol and acetoin.

In this study, we describe a novel method for producing valuable chemicals from glucose and xylose in Escherichia coli. The notable features in our method are avoidance of plasmids and expensive inducers for foreign gene expression to reduce production costs; foreign genes are knocked into the chromosome, and their expression is induced with xylose that is present in most biomass feedstock. As loci for the gene knock-in, lacZYA and some pseudogenes are chosen to minimize unexpected effects of the knock-in on cell physiology.

Bacterial cellular engineering by genome editing and gene silencing.

Genome editing is an important technology for bacterial cellular engineering, which is commonly conducted by homologous recombination-based procedures, including gene knockout (disruption), knock-in (insertion), and allelic exchange. In addition, some new recombination-independent approaches have emerged that utilize catalytic RNAs, artificial nucleases, nucleic acid analogs, and peptide nucleic acids. Apart from these methods, which directly modify the genomic structure, an alternative approach is to conditionally modify the gene expression profile at the posttranscriptional level without altering the genomes.

Observation of X-ray and Auger electron spectra in a 4π proportional counter for 4π(e, X)-γ coincidence measurements.

For the standardization of electron capture nuclides followed by γ-transitions, the 4π(e, X)-γ coincidence counting method is mainly adopted. To examine how the spectra of the (e, X) channel change with gas nature and pressure, pulse-height spectrum measurements of signals from a 4π pressurized proportional counter were carried out under various conditions for (54)Mn and (88)Y sources together with 4π(e, X)-γ coincidence counting. The spectra were measured for each half of the counter and for the combined 4π signal.

A vector library for silencing central carbon metabolism genes with antisense RNAs in Escherichia coli.

We describe here the construction of a series of 71 vectors to silence central carbon metabolism genes in Escherichia coli. The vectors inducibly express antisense RNAs called paired-terminus antisense RNAs, which have a higher silencing efficacy than ordinary antisense RNAs. By measuring mRNA amounts, measuring activities of target proteins, or observing specific phenotypes, it was confirmed that all the vectors were able to silence the expression of target genes efficiently.

Mortalin antibody-conjugated quantum dot transfer from human mesenchymal stromal cells to breast cancer cells requires cell-cell interaction.

The role of tumor stroma in regulation of breast cancer growth has been widely studied. However, the details on the type of heterocellular cross-talk between stromal and breast cancer cells (BCCs) are still poorly known. In the present study, in order to investigate the intercellular communication between human mesenchymal stromal cells (hMSCs) and breast cancer cells (BCCs, MDA-MB-231), we recruited cell-internalizing quantum dots (i-QD) generated by conjugation of cell-internalizing anti-mortalin antibody and quantum dots (QD).

Absorption and backscatter of internal conversion electrons in the measurements of surface contamination of ¹³⁷Cs.

We measured 4π and 2π counting efficiencies for internal conversion electrons (ICEs), gross β-particles and also β-rays alone with various source conditions regarding absorber and backing foil thickness using e-X coincidence technique. Dominant differences regarding the penetration, attenuation and backscattering properties among ICEs and β-rays were revealed. Although the abundance of internal conversion electrons of (137)Cs-(137)Ba is only 9.

Gene silencing in Escherichia coli using antisense RNAs expressed from doxycycline-inducible vectors.

Unlabelled: Here, we report on the construction of doxycycline (tetracycline analogue)-inducible vectors that express antisense RNAs in Escherichia coli. Using these vectors, the expression of genes of interest can be silenced conditionally. The expression of antisense RNAs from the vectors was more tightly regulated than the previously constructed isopropyl-β-D-galactopyranoside-inducible vectors.

A new carbon catabolite repression mutation of Escherichia coli, mlc∗, and its use for producing isobutanol.

Sugar derived from biomass is usually a mixture of glucose and other sugars. When mixed sugars are fed to Escherichia coli, glucose is preferentially utilized while other sugars remain unutilized. This phenomenon is known as carbon catabolite repression (CCR).

A simple and versatile data acquisition system for software coincidence and pulse-height discrimination in 4πβ-γ coincidence experiments.

A simple but versatile data acquisition system for software coincidence experiments is described, in which any time stamping and live time controller are not provided. Signals from β- and γ-channels are fed to separately two fast ADCs (16 bits, 25 MHz clock maximum) via variable delay circuits and pulse-height stretchers, and also to pulse-height discriminators. The discriminating level was set to just above the electronic noise.