Development of a strain for efficient degradation of polychlorinated biphenyls by patchwork assembly of degradation pathways

Rhodococcus jostii RHA1 accumulates chlorobenzoates (CBA) during the degradation of polychlorinated biphenyls (PCBs). CBA degradation is considered one of the rate-limiting steps in the complete degradation of PCBs. To reduce the accumulation of CBAs, the upper pathway enzyme genes for PCB degradation of RHA1 were introduced into a CBA-degrading bacterium, Burkholderia sp. NK8. The resulting recombinant strain exhibited no biphenyl 2,3-dioxygenase (BphA) activity encoded by bphAaAbAcAd genes, which encode the large and small subunits of the terminal oxygenase component and the ferredoxin and reductase subunits responsible for electron transfer from NADH to the large subunit. The remaining enzyme genes involved in the transformation of biphenyl to benzoate, bphB2C1D1, which encode dehydrogenase, ring-cleavage dioxygenase and hydrolase, conferred activities to NK8. To obtain the BphA activity of RHA1 in NK8, sets of BphA genes were constructed by combining the bphAaAbAcAd genes of RHA1 and bphA3A4 of Pseudomonas pseudoalcaligenes KF707, encoding the ferredoxin and reductase subunits. Hybrid derivatives of BphA containing the KF707 bphA3 conferred BphA activity to NK8, and a derivative containing the RHA1 bphAaAb and KF707 bphA3A4 genes exhibited the highest BphA activity. A plasmid containing the RHA1 bphAaAb and KF707 bphA3A4 genes plus the RHA1 bphB2C1D1 genes was constructed and introduced into NK8. The resulting recombinant strain efficiently degraded 2-, 3- and 4-chlorobiphenyls with an apparent reduction in CBA accumulation in comparison to the recombinant mutant strain, which had an insertion in the cbeA gene to inactivate CBA dioxygenase.     

Studies on the contents of water-soluble chlorides and water-soluble sulfates in food color aluminum lakes

Japan's Specifications and Standards for Food Additives, 7th Edition (JSFA-VII) does not set limits for total contents of water-soluble chlorides and water-soluble sulfates (water-soluble inorganic salts) in food color aluminum lakes (FC-Als). However, the regulatory limit is 2% in JECFA and CFR. We used column switching suppressor-type ion chromatography (CSS-IC) for determination of anions. The total contents of water-soluble inorganic salts in FC-Als (112 qualified samples) were determined using the modified CSS-IC from fiscal year 1998 to fiscal year 2003. Total contents of water-soluble inorganic salts in four samples exceeded 2%. From an international point of view, it is desirable that the total content of water-soluble inorganic salts in FC-Al should again be regulated in Japan.     

Effect of cellular inositol content on ethanol tolerance of Saccharomyces cerevisiae in sake brewing

The effect of cellular inositol content on the ethanol tolerance of sake yeast was investigated. In a static culture of strain K901 in a synthetic medium, when cells were grown in the presence of inositol in limited amount (L-cells), the inositol content of cells decreased by one-third that of cells grown in the presence of inositol in sufficient amount (H-cells). L-cells exhibited a higher death rate constant than H-cells in the presence of 12-20% ethanol, while no difference in specific ethanol production rate in the presence of 0-18% ethanol between the two cell types was observed. L-cells leaked more intracellular components, such as nucleotides, phosphate and potassium, in the presence of ethanol than H-cells. L-cells exhibited a lower intracellular pH value than H-cells, which represented the lowering of cell vitality by the decrease in H(+) extrusion activity. Furthermore, the plasma membrane H(+)-ATPase activity of L-cells was approximately one-half of that of H-cells. Therefore, it was considered that the decrease in viability in the presence of ethanol due to inositol limitation results from the lowering of H(+)-ATPase activity, which maintains the permeability barrier of the yeast membrane, ensuring the homeostasis of ions in the cytoplasm of yeast cells. It is assumed that the lowering of H(+)-ATPase activity due to inositol limitation is caused by the change in lipid environment of the enzyme, which is affected by inositol-containing glycerophospholipids such as phosphatidylinositol (PI), because in the PI-saturated mixed micellar assay system, the difference in H(+)-ATPase activity between L- and H-cells disappeared. In the early stage of sake mash, inositol limitation lowers the ethanol tolerance due to the decrease in H(+)-ATPase activity as in static culture. In the final stage of sake mash, the disruption of the ino1 gene responsible for inositol synthesis, resulted in a decrease in cell density. Furthermore, the ino1 disruptant, which was not capable of increasing the cellular inositol level in the final stage, exhibited a significantly higher methylene blue-staining ratio than the parental strain. It was suggested that the yeast cellular inositol level is one of the important factors which contribute to the high ethanol tolerance implied by the increased cell viability in the presence of ethanol.     

International mobility of researchers in robotics,computer vision and electron devices: A quantitative and comparative analysis

We investigated author information in scientific articles by approximately 7,000 researchers for a quantitative analysis of researchers’ international mobility. From top journals, we traced the movements of more than 2,200 researchers in the research domains of robotics, computer vision and electron devices. We categorized countries’ characteristics for the balance between the inflow and the outflow of researchers moving internationally. Flow patterns of international mobility confirm that the United States, China and India exhibit the greatest global flows of researchers, with Singapore and Hong Kong attracting remarkable numbers of researchers from other countries. International mobility focusing on institutions reveals that universities in Singapore receive as many foreign researchers as do research universities in the United States. Furthermore, firms and international collaborative research institutes act as alternative receivers to the universities in the electron devices research domain.     

Quantitative analysis of collaborative and mobility networks

This study proposes a quantitative analysis of researcher mobility (i.e. transfer from one institution to another) and collaborative networks on the basis of author background data extracted from biographical notes in scientific articles to identify connections that are not revealed via simple co-authorship analysis. Using a top-ranked journal in the field of computer vision, we create a layered network that describes various aspects of author backgrounds, demonstrating a geographical distribution of institutions. We classify networks according to various dimensions including authors, institutions and countries. The results of the quantitative analysis indicate that mobility networks extend beyond the typical collaborative networks describing institutional and international relationships. We also discuss sectoral collaboration considering the mobility networks. Our findings indicate a limitation of collaborative analysis based on bibliometric data and the importance of tracing researcher mobility within potential networks to identify the true nature of scientific collaboration.     

Microphase-separated structure and mechanical properties of novel polyurethane elastomers prepared with ether based diisocyanate

A diisocyanate baring ether bonds, 1,2-bis(isocyanate)ethoxyethane (TEGDI), was used for the preparation of polyurethane elastomers (PUEs). The PUEs were synthesized with either TEGDI or HDI, poly(oxytetramethylene) glycol (PTMG), and curing agents by a prepolymer method. 1,6-Hexamethylene diisocyanate (HDI) was also used as a control diisocyanate. The TEGDI-based PUEs exhibited highly softened property on account of flexibility of TEGDI itself and weaker phase separation. Another TEGDI-based PUEs were prepared with either poly(oxypropylene) glycol (PPG) or poly(caprolactone) glycol (PCL). Microphase-separated structure of these TEGDI-based PUEs are quite different from those with general diisocyanates and the PUEs were made be greatly softened.     

Echocardiography and fatty acid single photon emission tomography in predicting reversibility of regional left ventricular dysfunction after coronary angioplasty

It has often been proposed that young children are not capable of distinguishing mistakes from lies and that they do not discriminate between the reactions that are generated by innocent and negligent mistakes. In our investigation, children aged 3 to 5 years were asked to choose whether a perpetrator had made a mistake or had lied about a food's contact with contaminants and were required to indicate whether this choice would produce a neutral or a negative reaction in the facial expression of a bystander. In this context, many children distinguished mistakes from lies and displayed an incipient ability to discriminate between lies and negligent mistakes that often generate negative reactions and innocent mistakes that do not.     

Concentration-dependent block of sodium current in guinea pig ventricular myocytes by a class III antiarrhythmic agent, MS-551

The 32P-post-labelling assay for DNA adduct quantification gives the opportunity to examine endogenous exposure to DNA reactive compounds. Most human biomonitoring studies applied white blood cells (WBC) or cells obtained by broncho-alveolar lavages (BAL) as source of DNA, but still it is not clear what cell type represents the most reliable indicator for exposure to cigarette smoke-associated genotoxins. At first, we examined DNA adduct levels by means of nuclease P1 (NP1) enriched 32P-post-labelling in separated WBC subpopulations after in vitro incubations for 18 h with 10 microM benzo[a]pyrene (B[a]P). DNA adduct levels were highest in monocytes (10.7 +/- 2.9 adducts/10(8) nucleotides, n = 8), followed by lymphocytes (5.9 +/- 1.7, n = 8), and granulocytes (0.5 +/- 0.2, n = 8). Secondly, aromatic-DNA adduct levels were determined in BAL cells and WBC-subsets from (non-)smoking volunteers. In smoking individuals, adduct levels were in the ranking order: BAL cells (3.7 +/- 1.0, n = 5) > monocytes (2.0 +/- 0.5, n = 8) > or = lymphocytes (1.6 +/- 0.4, n = 8) > granulocytes (0.8 +/- 0.2, n = 8) by NP1-enrichment and monocytes (9.0 +/- 3.2, n = 5) > or = lymphocytes (8.0 +/- 2.1, n = 6) > granulocytes (2.1 +/- 0.3, n = 7) by butanol-enriched 32P-post-labelling. Aromatic-DNA adduct levels were significantly higher in WBC-subsets of smokers as compared with non-smokers, except for DNA adducts in granulocytes using butanol enrichment. Thirdly, dose-response relationships were investigated in mononuclear white blood cells (MNC, i.e. monocytes plus lymphocytes) and BAL-cells of a larger group of smoking individuals (n = 78). Adduct levels in MNC were related to daily exposure to cigarette-tar (r = 0.31, P < 0.01). Adduct levels in BAL cells seemed to be correlated with pack-years, but after correction for age this relationship was lost. Butanol extraction resulted in 5-6-fold higher DNA adduct levels in MNC, whereas butanol extraction of BAL-DNA of the same individuals yielded only 2-fold higher adduct levels. The two enrichment procedures of 32P-post-labelling were correlated in BAL cells (r = 0.86, P < 0.001, n = 12). We conclude that particularly MNC are good surrogates for the detection of smoking-related DNA adducts.     

Substance P- and calcitonin gene-related peptide-containing nerve fibers in the nasal mucosa of chronically hypoxic rats

Changes made in 1997 and 1998 in the U.S. childhood immunization schedule are discussed, with a focus on the use of poliovirus, pertussis, and combination vaccines. Oral poliovirus vaccine (OPV), the vaccine of choice for all four doses in the polio immunization series since 1962, can cause vaccine-associated paralytic poliomyelitis (VAPP). The inactivated poliovirus vaccine (IPV) has not been associated with VAPP but must be administered by injection and provides inferior intestinal immunity. With the reduced threat of poliovirus importation into the United States, the risk of VAPP, although low, has become less acceptable. The Centers for Disease Control and Prevention accordingly recommended a shift from OPV to IPV in the childhood immunization schedule for the United States, effective January 1997. A sequential OPV and IPV series is recommended, but the schedule includes an OPV-only option, which may be preferred in order to avoid the required injections, and an IPV-only option, which is recommended for immunocompromised persons and their contacts. Concern over local and systemic reactions associated with whole-cell pertussis vaccines, in addition to controversy over a possible relationship between the whole-cell vaccine and neurologic damage, has led to the development of new diphtheria and tetanus toxoids and acellular pertussis vaccine products for use in the diphtheria and tetanus toxoids and pertussis immunization series. Several combination products were licensed in 1997, and more are on the way. This will mean fewer inoculations for children. Increased use of IPV and acellular pertussis products could reduce the frequency of VAPP due to OPV and the local and systemic reactions associated with whole-cell pertussis vaccine.