Infrared Imaging of z=2.43 Radio Galaxy B3 0731+438 with the Subaru Telescope - Detection of Hα\alpha Ionization Cones of a Powerful Radio Galaxy

We report on infrared imaging observations of the z=2.429 radio galaxy B3 0731+438 with the Subaru telescope. The images were taken with the K'-band filter and the 2.25 um narrow-band filter to examine the structure and properties of the Ha+[N II] 6548,6583 emission-line components. The Ha+[N II] emission-line image shows biconical lobes with an extent of 40 kpc, which are aligned with the radio axis. The rest-frame equivalent widths of the emission lines at these cones are as large as 1100 AA, and can be well explained by a gas-cloud model photoionized by power-law continuum radiation. The isotropic ionizing photon luminosity necessary to ionize the hydrogen gas in these cones amounts to 1e57(photons/s), which is larger than that in the majority of radio-loud QSOs. From these results, we propose that the Ha alignment effect in this object is produced by biconical gas clouds, which are swept up by the passage of radio jets, and are ionized by strong UV radiation from a hidden AGN. The continuum image consists of two components, a stellar-like point source and an extended diffuse galaxy. These are supposed to be a type-2 AGN and its host galaxy. The SED is fitted by a combination of spectra of a reddened dust-scattered AGN and an instantaneous starburst population of 500 Myr old. The stellar mass of the galaxy is estimated to be 3e11 M_solar, which is as large as that of typical 3C radio galaxies at z=1.Comment: 12 pages, 4 Postscript figures, uses PASJ2.sty, PASJ95.sty, PASJadd.sty. Accepted for publication in PASJ (2000

Subaru Observations for the K-band Luminosity Distribution of Galaxies in Clusters near to 3C 324 at z∼\sim1.2

We investigate the $K$-band luminosity distribution of galaxies in the region of clusters at $z\sim1.2$ near to the radio galaxy 3C 324. The imaging data were obtained during the commissioning period of the Subaru telescope. There is a significant excess of the surface number density of the galaxies with $K =$ 17--20 mag in the region within $\sim$ 40'' from 3C 324. At this bright end, the measured luminosity distribution shows a drop, which can be represented by the exponential cut off of the Schechter-function formula; the best-fitted value of the characteristic magnitude, $K^{*}$, is $\sim 18.4\pm0.8$. This measurement follows the evolutionary trend of the $K^*$ of the rich clusters observed at an intermediate redshift, which is consistent with passive evolution models with a formation redshift z_f \gtsim 2. At K \gtsim 20 mag, however, the excess of the galaxy surface density in the region of the clusters decreases abruptly, which may imply that the luminosity function of the cluster galaxies has a negative slope at the faint end. This may imply strong luminosity segregation between the inner and outer parts of the clusters, or some deficit of faint galaxies in the cluster central region of the cluster.Comment: 12 pages, 9 figures, accepted for publication in PAS

High-Resolution Near-Infrared Imaging of the Powerful Radio Galaxy 3C 324 at z = 1.21 with the Subaru Telescope

We have obtained high-resolution K'-band images of the powerful z=1.206 radio galaxy 3C 324 with the Subaru telescope under seeing conditions of 0.3--0.4 arcsec. We clearly resolved the galaxy and directly compared it to the optical images obtained with the Hubble Space Telescope. The host galaxy of 3C 324 is revealed to be a moderately luminous elliptical galaxy with a smooth light profile. The effective radius of the galaxy, as determined by profile fitting, is 1.3+-0.1 arcsec (1.2 kpc), which is significantly smaller than the value of 2.2 arcsec, published in Best et al. (1998, MNRAS, 292, 758). The peak of the K'-band light coincides with the position of the radio core, which implies that the powerful AGN lies at the nucleus of the host galaxy. The peak also coincides with the gap in the optical knotty structures which may be a dust lane hiding the UV-optical emission of the AGN from our line of sight; it is very likely that we are seeing the obscuring structure almost edge-on. We clearly detected the `aligned component' in the K'-band image by subtracting a model elliptical galaxy from the observed image. The red R_F702W-K color of the outer region of the galaxy avoiding the aligned component indicates that the near infrared light of the host galaxy is dominated by an old stellar population.Comment: 21 pages (10 figures), accepted for publication in PAS

Lineage-specific positive selection at the merozoite surface protein 1 (msp1) locus of Plasmodium vivax and related simian malaria parasites

<p>Abstract</p> <p>Background</p> <p>The 200 kDa merozoite surface protein 1 (MSP-1) of malaria parasites, a strong vaccine candidate, plays a key role during erythrocyte invasion and is a target of host protective immune response. <it>Plasmodium vivax</it>, the most widespread human malaria parasite, is closely related to parasites that infect Asian Old World monkeys, and has been considered to have become a parasite of man by host switch from a macaque malaria parasite. Several Asian monkey parasites have a range of natural hosts. The same parasite species shows different disease manifestations among host species. This suggests that host immune responses to <it>P. vivax</it>-related malaria parasites greatly differ among host species (albeit other factors). It is thus tempting to invoke that a major immune target parasite protein such as MSP-1 underwent unique evolution, depending on parasite species that exhibit difference in host range and host specificity.</p> <p>Results</p> <p>We performed comparative phylogenetic and population genetic analyses of the gene encoding MSP-1 (<it>msp1</it>) from <it>P. vivax </it>and nine <it>P. vivax</it>-related simian malaria parasites. The inferred phylogenetic tree of <it>msp1 </it>significantly differed from that of the mitochondrial genome, with a striking displacement of <it>P. vivax </it>from a position close to <it>P. cynomolgi </it>in the mitochondrial genome tree to an outlier of Asian monkey parasites. Importantly, positive selection was inferred for two ancestral branches, one leading to <it>P. inui </it>and <it>P. hylobati </it>and the other leading to <it>P. vivax</it>, <it>P. fieldi </it>and <it>P. cynomolgi</it>. This ancestral positive selection was estimated to have occurred three to six million years ago, coinciding with the period of radiation of Asian macaques. Comparisons of <it>msp1 </it>polymorphisms between <it>P. vivax</it>, <it>P. inui </it>and <it>P. cynomolgi </it>revealed that while some positively selected amino acid sites or regions are shared by these parasites, amino acid changes greatly differ, suggesting that diversifying selection is acting species-specifically on <it>msp1</it>.</p> <p>Conclusions</p> <p>The present results indicate that the <it>msp1 </it>locus of <it>P. vivax </it>and related parasite species has lineage-specific unique evolutionary history with positive selection. <it>P. vivax </it>and related simian malaria parasites offer an interesting system toward understanding host species-dependent adaptive evolution of immune-target surface antigen genes such as <it>msp1</it>.</p

Copper-Catalyzed Enantioselective Allylic Substitution with Alkylboranes

The first catalytic enantioselective allylic substitution reaction with alkylboron compounds has been achieved. The reaction between alkyl-9-BBN reagents and primary allylic chlorides proceeded with excellent γ-selectivities and high enantioselectivities under catalysis of a Cu­(I)–DTBM-SEGPHOS system. The protocol produces terminal alkenes with an allylic stereogenic center branched with functionalized sp³-alkyl groups. The reaction with a γ-silicon-substituted allyl chloride affords an efficient strategy for the enantioselective synthesis of functionalized α-stereogenic chiral allylsilanes

Plasmodium falciparum mitochondrial genetic diversity exhibits isolation-by-distance patterns supporting a sub-Saharan African origin

The geographical distribution of single nucleotide polymorphism (SNP) in the mitochondrial genome of the human malaria parasite Plasmodium falciparum was investigated. We identified 88 SNPs in 516 isolates from seven parasite populations in Africa, Southeast Asia and Oceania. Analysis of the SNPs postulated a sub- Saharan African origin and recovered a strong negative correlation between within-population SNP diversity and geographic distance from the putative African origin over Southeast Asia and Oceania. These results are consistent with those previously obtained for nuclear genome-encoded housekeeping genes, indicating that the pattern of inheritance does not substantially affect the geographical distribution of SNPs

Giemsa-stained thin blood smear showing an immature schizont.

<p>Giemsa-stained thin blood smear showing an immature schizont.</p