Protein kinase CK2 localizes to sites of DNA double-strand break regulating the cellular response to DNA damage

<p>Abstract</p> <p>Background</p> <p>The DNA-dependent protein kinase (DNA-PK) is a nuclear complex composed of a large catalytic subunit (DNA-PKcs) and a heterodimeric DNA-targeting subunit Ku. DNA-PK is a major component of the non-homologous end-joining (NHEJ) repair mechanism, which is activated in the presence of DNA double-strand breaks induced by ionizing radiation, reactive oxygen species and radiomimetic drugs. We have recently reported that down-regulation of protein kinase CK2 by siRNA interference results in enhanced cell death specifically in DNA-PKcs-proficient human glioblastoma cells, and this event is accompanied by decreased autophosphorylation of DNA-PKcs at S2056 and delayed repair of DNA double-strand breaks.</p> <p>Results</p> <p>In the present study, we show that CK2 co-localizes with phosphorylated histone H2AX to sites of DNA damage and while CK2 gene knockdown is associated with delayed DNA damage repair, its overexpression accelerates this process. We report for the first time evidence that lack of CK2 destabilizes the interaction of DNA-PKcs with DNA and with Ku80 at sites of genetic lesions. Furthermore, we show that CK2 regulates the phosphorylation levels of DNA-PKcs only in response to direct induction of DNA double-strand breaks.</p> <p>Conclusions</p> <p>Taken together, these results strongly indicate that CK2 plays a prominent role in NHEJ by facilitating and/or stabilizing the binding of DNA-PKcs and, possibly other repair proteins, to the DNA ends contributing to efficient DNA damage repair in mammalian cells.</p

Using Rare Earth Elements to Constrain Particulate Organic Carbon Flux in the East China Sea

Fluxes of particulate organic carbon (POC) in the East China Sea (ECS) have been reported to decrease from the inner continental shelf towards the outer continental shelf. Recent research has shown that POC fluxes in the ECS may be overestimated due to active sediment resuspension. To better characterize the effect of sediment resuspension on particle fluxes in the ECS, rare earth elements (REEs) and organic carbon (OC) were used in separate two-member mixing models to evaluate trap-collected POC fluxes. The ratio of resuspended particles from sediments to total trap-collected particles in the ECS ranged from 82-94% using the OC mixing model, and 30-80% using the REEs mixing model, respectively. These results suggest that REEs may be better proxies for sediment resuspension than OC in high turbidity marginal seas because REEs do not appear to undergo degradation during particle sinking as compared to organic carbon. Our results suggest that REEs can be used as tracers to provide quantitative estimates of POC fluxes in marginal sea

Tailoring Plasmonic Enhanced Upconversion in Single NaYF4:Yb3+/Er3+ Nanocrystals

By using silver nanoplatelets with a widely tunable localized surface plasmon resonance (LSPR) and their corresponding local field enhancement, here we show large manipulation of plasmonic enhanced upconversion in NaYF4:Yb3+/Er3+ nanocrystals at the single particle level. In particular, we show that when the plasmonic resonance of silver nanolplatelets is tuned to 656 nm, matching the emission wavelength, an upconversion enhancement factor ~5 is obtained. However, when the plasmonic resonance is tuned to 980 nm, matching the nanocrystal absorption wavelength, we achieve an enhancement factor of ~22 folds. The precise geometric arrangement between fluorescent nanoparticles and silver nanoplatelets allows us to make, for the first time, a comparative analysis between experimental results and numerical simulations, yielding a quantitative agreement at the single particle level. Such a comparison lays the foundations for a rational design of hybrid metal-fluorescent nanocrystals to harness the upconversion enhancement for biosensing and light harvesting applications

Production of xylooligosaccharides from forest waste by membrane separation and Paenibacillus xylanase hydrolysis

Xylooligosaccharides (XO), derived from the alkaline (NaOH) extractant of Mikania micrantha, were produced using multiple staged membrane separation and enzymatic xylanolysis. Staged nanofiltration (NMX), ultrafiltration (EUMX), and centrifugation (EMX) processes for the ethanol precipitates were conducted. NMX recovered 97.26% of total xylose and removed 73.18% of sodium ions. Concentrations of total xylose were raised from 10.98 to 51.85 mg/mL by the NMX process. Recovered xylan-containing solids were hydrolyzed by the recombinant Paenibacillus xylanase. 68% XO conversions from total xylose of NMX was achieved in 24 hours. Xylopentaose (DP 5) was the major product from NMX and EMX hydrolysis. Xylohexaose (DP 6) was the major product from EUMX hydrolysis. Results of the present study suggest the applicability for XO production by nanofiltration, as NMX gave higher XO yields compared to those from a conventional ethanol-related lignocellulosic waste conversion process

Dichlorido{(E)-2,4,6-trimethyl-N-[phen­yl(2-pyridyl)methyl­idene]aniline-κ2 N,N′}palladium(II)

The title complex, [PdCl2(C21H20N2)], contains a PdII atom in a slightly distorted square-planar coordination environment defined by two N atoms from one 2,4,6-trimethyl-N-[phen­yl(2-pyrid­yl)methyl­idene]aniline ligand and two Cl atoms, forming a five-membered ring (N—Pd—N—C—C)

RNA Interference inhibits Hepatitis B Virus of different genotypes in Vitro and in Vivo

<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) infection increases the risk of liver disease and hepatocellular carcinoma. Small interfering RNA (siRNA) can be a potential new tool for HBV therapy. Given the high heterogeneity of HBV strains and the sensitivity towards sequences changes of siRNA, finding a potent siRNA inhibitor against the conservative site on the HBV genome is essential to ensure a therapeutic application.</p> <p>Results</p> <p>Forty short hairpin RNA (shRNA) expression plasmids were constructed to target conserved regions among nine HBV genotypes. HBV 1.3-fold genome plasmids carrying various genotypes were co-transfected with shRNA plasmids into either Huh7 cells or mice. The levels of various viral markers were examined to assess the anti-HBV efficacy of siRNA. Four (B245, B376, B1581 and B1789) were found with the ability to potently inhibit HBV RNA, DNA, surface antigen (HBsAg), e antigen (HBeAg) and core antigen (HBcAg) expression in HBV genotypes A, B, C, D and I (a newly identified genotype) in Huh7 cells and in mice. No unusual cytotoxicity or off-target effects were noted.</p> <p>Conclusions</p> <p>Such siRNA suggests an alternate way of inhibiting various HBV genotypes in vitro and in vivo, promising advances in the treatment of HBV.</p

Herbal Medicine in Uterine Fibroid

Uterine fibroids, also known as uterine leiomyoma is the most common benign tumor of the uterus found in women of reproductive age. Uterine fibroids are the cause of major quality-of-life issues for approximately 25% of all women who suffer from clinically significant symptoms of uterine fibroid. Despite the prevalence of fibroid, currently, there are no effective treatment options for fibroid. The lack of understanding of the etiology of fibroid contributes to the scarcity of medical therapies available. Sex steroid hormones, dysregulation of cell signaling pathways, miRNA expression, and cytogenetic abnormalities may all implicate in fibroid etiology. Several herbal medicines have been used as anti-inflammation and antitumor agents. All of them have a common capability to inhibit expression of pro-inflammatory cytokines, proliferative genes, and pro-angiogenetic genes. Exploring herbal medicines as remedies lighten the hope of treatment. In the current review article, we discuss signal transduction pathways activated herbal medicines. We also address the possibility of using herbal medicines for uterine fibroid treatment