35 research outputs found
Chromosomal polymorphism of ribosomal genes in the genus Oryza
The genes encoding for 18S–5.8S–28S ribosomal RNA (rDNA) are both conserved and diversified. We used rDNA as probe in the fluorescent in situ hybridization (rDNA-FISH) to localized rDNAs on chromosomes of 15 accessions representing ten Oryza species. These included cultivated and wild species of rice, and four of them are tetraploids. Our results reveal polymorphism in the number of rDNA loci, in the number of rDNA repeats, and in their chromosomal positions among Oryza species. The numbers of rDNA loci varies from one to eight among Oryza species. The rDNA locus located at the end of the short arm of chromosome 9 is conserved among the genus Oryza. The rDNA locus at the end of the short arm of chromosome 10 was lost in some of the accessions. In this study, we report two genome specific rDNA loci in the genus Oryza. One is specific to the BB genome, which was localized at the end of the short arm of chromosome 4. Another may be specific to the CC genome, which was localized in the proximal region of the short arm of chromosome 5. A particular rDNA locus was detected as stretched chromatin with bright signals at the proximal region of the short arm of chromosome 4 in O.grandiglumis by rDNA-FISH. We suggest that chromosomal inversion and the amplification and transposition of rDNA might occur during Oryza species evolution. The possible mechanisms of cyto-evolution in tetraploid Oryza species are discussed
The impact of a weight reduction program with and without meal-replacement on health related quality of life in middle-aged obese females
Reticulate evolution in Panicum (Poaceae): the origin of tetraploid broomcorn millet, P. miliaceum
Cytological and molecular relationships between Larix decidua, L. leptolepis and Larix x eurolepis: identification of species-specific Chromosoms and synchronization of mitotic cells
Repression of mammary adipogenesis by genistein limits mammosphere formation of human MCF-7 cells
Spectroscopic classification of a complete sample of astrometrically-selected quasar candidates using Gaia DR2
Here we explore the efficiency and fidelity of a purely astrometric selection
of quasars as point sources with zero proper motions in the {\it Gaia} data
release 2 (DR2). We have built a complete candidate sample including 104
Gaia-DR2 point sources brighter than mag within one degree of the north
Galactic pole (NGP), all with proper motions consistent with zero within
2 uncertainty. In addition to pre-existing spectra, we have secured
long-slit spectroscopy of all the remaining candidates and find that all 104
stationary point sources in the field can be classified as either quasars (63)
or stars (41). The selection efficiency of the zero-proper-motion criterion at
high Galactic latitudes is thus . Based on this complete quasar
sample we examine the basic properties of the underlying quasar population
within the imposed limiting magnitude. We find that the surface density of
quasars is 20 deg, the redshift distribution peaks at , and
that only eight systems () show significant dust reddening. We
then explore the selection efficiency of commonly used optical, near- and
mid-infrared quasar identification techniques and find that they are all
complete at the level compared to the astrometric selection. Finally,
we discuss how the astrometric selection can be improved to an efficiency of
by including an additional cut requiring parallaxes of the
candidates to be consistent with zero within 2. The selection
efficiency will further increase with the release of future, more sensitive
astrometric measurement from the Gaia mission. This type of selection, purely
based on the astrometry of the quasar candidates, is unbiased in terms of
colours and emission mechanisms of the quasars and thus provides the most
complete census of the quasar population within the limiting magnitude of Gaia.Comment: Accepted for publication in A&A. Abstract abridge
Expression patterns, molecular markers and genetic diversity of insect-susceptible and resistant Barbarea genotypes by comparative transcriptome analysis
6,7,4′-Trihydroxyisoflavone inhibits HCT-116 human colon cancer cell proliferation by targeting CDK1 and CDK2
Colon cancer is a common epithelial malignancies worldwide. Epidemiologic evidence has shown that nutrition and dietary components are important environmental factors involved in the development of this disease. We investigated the biological activity of 6,7,4′-trihydroxyisoflavone (6,7,4′-THIF, a metabolite of daidzein) in in vitro and in vivo models of human colon cancer. 6,7,4′-THIF suppressed anchorage-dependent and -independent growth of HCT-116 and DLD1 human colon cancer cells more effectively than daidzein. In addition, 6,7,4′-THIF induced cell cycle arrest at the S and G2/M phases in HCT-116 human colon cancer cells. Western blot analysis revealed that 6,7,4′-THIF effectively suppressed the expression of cyclin-dependent kinase (CDK) 2, but had no effect on other S- or G2/M-phase regulatory proteins such as cyclin A, cyclin B1 or CDK1. Daidzein did not affect the expression of any of these proteins. In kinase and pull-down assays, 6,7,4′-THIF, but not daidzein, inhibited CDK1 and CDK2 activities in HCT-116 cells by directly interacting with CDK1 and CDK2. In a xenograft mouse model, 6,7,4′-THIF significantly decreased tumor growth, volume and weight of HCT-116 xenografts. 6,7,4′-THIF bound directly to CDK1 and CDK2 in vivo, resulting in the suppression of CDK1 and CDK2 activity in tumors corresponding with our in vitro results. Collectively, these results suggest that CDK1 and CDK2 are potential molecular targets of 6,7,4′-THIF to suppress HCT-116 cell proliferation in vitro and in vivo. These findings provide insight into the biological actions of 6,7,4′-THIF and might establish a molecular basis for the development of new cancer therapeutic agents