Copper-Assisted Direct Nitration of Cyclic Ketones with Ceric Ammonium Nitrate for the Synthesis of Tertiary α‑Nitro-α-substituted Scaffolds

An efficient and direct Cu-assisted nitrating approach to create synthetically valuable and challenging tertiary α-nitro-α-substituted moieties has been developed using ceric ammonium nitrate as a nitrating reagent, oxidant, and Lewis acid. Notably, the commonly used clinical drug ketamine was smoothly synthesized in four steps

Floral traits of <i>Cyananthus delavayi</i> and its pollinator in the natural population.

<p>A: Dissected view of perfect flowers, showing long throat hair (TH) and pollen presentation area (PP); B: Dissected view of female flowers, showing short throat hair and exerted stigma; C: Pollen-collecting <i>Halictus</i> sp. crawling into a perfect flower in the male phase. A and B are modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117149#pone.0117149.ref020" target="_blank">20</a>]. All pictures are photographed by Yang Niu.</p

A Sexually Dimorphic Corolla Appendage Affects Pollen Removal and Floral Longevity in Gynodioecious <i>Cyananthus delavayi</i> (Campanulaceae)

<div><p>The floral traits of bisexual flowers may evolve in response to selection on both male and female functions, but the relative importance of selection associated with each of these two aspects is poorly resolved. Sexually dimorphic traits in plants with unisexual flowers may reflect gender-specific selection, providing opportunities for gaining an increased understanding of the evolution of specific floral traits. We examined sexually dimorphic patterns of floral traits in perfect and female flowers of the gynodioecious species <i>Cyananthus delavayi</i>. A special corolla appendage, the throat hair, was investigated experimentally to examine its influences on male and female function. We found that perfect flowers have larger corollas and much longer throat hairs than female flowers, while female ones have much exerted stigmas. The presence of throat hairs prolonged the duration of pollen presentation by restricting the amount of pollen removed by pollen-collecting bees during each visit. Floral longevity was negatively related to the rate of pollen removal. When pollen removal rate was limited in perfect flowers, the duration of the female phases diminished with the increased male phase duration. There was a weak negative correlation between throat hair length and seed number per fruit in female flowers, but this correlation was not significant in perfect flowers. These results suggest that throat hairs may enhance male function in terms of prolonged pollen presentation. However, throat hairs have no obvious effect on female function in terms of seed number per fruit. The marked sexual dimorphism of this corolla appendage in <i>C. delavayi</i> is likely to have evolved and been maintained by gender-specific selection.</p></div

Pollen removal and throat hair manipulation had significant effects on floral longevity in perfect flowers.

<p>Black, white and gray bars represent male, neutral and female phases, respectively. Solid circles represent the proportion of male phase duration (male phase divided by total floral longevity). Along the X-axis, 100% PR, 50% PR and 0% PR indicate pollen completely removed, 50% pollen removed and no pollen removed, respectively (these groups had pollinators excluded); NHR indicates the hair-removal group covered by netting; HR and C indicate hair-removal and natural control groups open to pollinators, respectively. Different lower-case letters above the bars indicate significant differences in total floral longevity at the 0.01 level. Different capital letters on the black bars indicate significant differences in male phase duration (and also in the proportion of male phase) at the 0.01 level. Numbers in brackets are sample sizes. Bars are standard errors.</p

The Pearson correlation between throat hair length and seed number per fruit.

<p>The correlation was not significant in perfect flowers (A) but marginal significant in female flowers (B).</p

GFP expression in SK-BR-3 cells treated for 48h by laser confocal microscopy.

<p>The figures showed above were merged photos in which cell nucleus was dyed with Hoechst 33342. The green fluorescence was prominent after 48 hours. Normal: cells without treatment; Neg: cells stably expressed shRNA-neg-miR-155; shmiR1: cells stably expressed shRNA-1-miR-155; shmiR2: cells stably expressed shRNA-2-miR-155; Radiation: cells receiving 6 Gy of radiation treatment.</p

MiRNA-Embedded ShRNAs for Radiation-Inducible LGMN Knockdown and the Antitumor Effects on Breast Cancer

<div><p>Legumain (LGMN) is highly expressed in breast cancer (BC) and other solid tumors and is a potential anticancer target. Here we investigate the anti-tumor effects of short hairpin RNAs (shRNAs) targeting LGMN embedded in a microRNA-155 (miR-155) architecture, which is driven by a radiation-inducible chimeric RNA polymerase II (Pol II) promoter. Lentiviral vectors were generated with the chimeric promoter which controlled the expression of downstream shRNA-miR-155 cassette. Fluorescence was observed by using confocal microscopy. Real-time quantitative PCR and Western blotting were used to determine the expression level of LGMN, MMP2, and MMP9. Furthermore, the proliferation and invasive ability of BC cells was analyzed via plate colony formation and invasion assays. Here we demonstrated that the chimeric promoter could be effectively induced by radiation treatment. Furthermore, the shRNA-miR-155 cassette targeting LGMN could be effectively activated by the chimeric promoter. Radiation plus knockdown of LGMN impairs colony formation and dampens cell migration and invasion in BC cells. Inhibition of LGMN downregulates MMP2 and MMP9 expression in BC cells. Pol II-driven shRNA-miR-155 could effectively suppress the growth and invasiveness of BC cells, and that the interference effects could be regulated by radiation doses. Moreover, knockdown of LGMN alleviates the aggressive phenotype of BC cells through modulating MMPs expression.</p></div

Radiation exposure initiates knockdown of LGMN.

<p>(<b>A)</b> LGMN mRNA in SK-BR-3 cells was detected by RT-PCR after 24 hs of radiation exposure. GAPDH served as an internal control. <b>(B)</b> Quantification of LGMN mRNA expression in SK-BR-3 cells by RT-PCR. <b>(C)</b> LGMN protein in SK-BR-3 cells was detected by Western blotting after 72 hs of radiation exposure, β-actin served as an internal control. <b>(D)</b> Quantification of LGMN protein expression in SK-BR-3 cells by Western blotting. (<b>E)</b> LGMN mRNA in MDA-MB-231 cells was detected by RT-PCR after 24 hs of radiation exposure. <b>(F)</b> Quantification of LGMN mRNA expression in MDA-MB-231 cells by RT-PCR. <b>(G)</b> LGMN protein in MDA-MB-231 cells was detected by Western blotting after 72 hs of radiation exposure. <b>(H)</b> Quantification of LGMN protein expression in MDA-MB-231 cells by Western blotting. **<i>P</i><0.01. Data was shown as the means ± SD from three independent experiments. The group definition is the same as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163446#pone.0163446.g001" target="_blank">Fig 1</a>.</p

Radiation induced knockdown of LGMN impairs colony formation.

<p><b>(A)</b> Representative images of clone-forming assay of SK-BR-3 cells receiving different treatments. <b>(B)</b> Comparison of cloning efficiency of SK-BR-3 cells. <b>(C)</b> Representative images of clone-forming assay of MDA-MB-231 cells receiving different treatments. <b>(D)</b> Comparisons of cloning efficiency of MDA-MB-231 cells. ** <i>P</i><0.01. Data was shown as the means ± SD from three independent experiments. The group definition is the same as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163446#pone.0163446.g001" target="_blank">Fig 1</a>.</p

Transwell invasion assay in different treatment groups.

<p><b>(A)</b> Representative images of the invasion assay in SK-BR-3 cells. (a) Normal; (b) Neg+R; (c) shmiR1+R; (d) shmiR2+R. <b>(B)</b> Comparisons of the cell counts in different groups of SK-BR-3 cells. <b>(C)</b> Representative images of the cell invasion assays in MDA-MB-231 cells. (a) Normal; (b) Neg+R; (c) shmiR1+R; (d) shmiR2+R. <b>(D)</b> Comparisons of the cell counts in different groups of MDA-MB-231 cells. ** <i>P</i><0.01. Data was shown as the means ± SD from three independent experiments. The group definition is the same as <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163446#pone.0163446.g001" target="_blank">Fig 1</a>.</p