The de novo methylation activity of Dnmt3a is distinctly different than that of Dnmt1

BACKGROUND: Though Dnmt1 is considered the primary maintenance methyltransferase and Dnmt3a and Dnmt3b are considered de novo methyltransferases in mammals, these three enzymes may work together in maintaining as well as establishing DNA methylation patterns. It has been proposed that Dnmt1 may carry out de novo methylation at sites in the genome with transient single-stranded regions, such as replication origins, and then spread methylation from these nucleation sites in vivo, even though such activity has not been reported. RESULTS: In this study, we show that Dnmt3a does not act on single-stranded substrates in vitro, indicating that Dnmt3a is not likely to initiate DNA methylation at such proposed nucleation sites. Dnmt3a shows similar methylation activity on unmethylated and hemimethylated duplex DNA, though with some substrate preference. Unlike Dnmt1, pre-existing cytosine methylation at CpG sites or non-CpG sites does not stimulate Dnmt3a activity in vitro and in vivo. CONCLUSION: The fact that Dnmt3a does not act on single stranded DNA and is not stimulated by pre-existing cytosine methylation indicates that the de novo methylation activity of Dnmt3a is quite different from that of Dnmt1. These findings are consistent with a model in which Dnmt3a initiates methylation on one of the DNA strands of duplex DNA, and these hemimethylated sites then stimulate Dnmt1 activity for further methylation

The Taiwan ECDFS Near-Infrared Survey: Ultra-deep J and Ks Imaging in the Extended Chandra Deep Field-South

We present ultra-deep J and Ks imaging observations covering a 30' * 30' area of the Extended Chandra Deep Field-South (ECDFS) carried out by our Taiwan ECDFS Near-Infrared Survey (TENIS). The median 5-sigma limiting magnitudes for all detected objects in the ECDFS reach 24.5 and 23.9 mag (AB) for J and Ks, respectively. In the inner 400 arcmin^2 region where the sensitivity is more uniform, objects as faint as 25.6 and 25.0 mag are detected at 5-sigma. So this is by far the deepest J and Ks datasets available for the ECDFS. To combine the TENIS with the Spitzer IRAC data for obtaining better spectral energy distributions of high-redshift objects, we developed a novel deconvolution technique (IRACLEAN) to accurately estimate the IRAC fluxes. IRACLEAN can minimize the effect of blending in the IRAC images caused by the large point-spread functions and reduce the confusion noise. We applied IRACLEAN to the images from the Spitzer IRAC/MUSYC Public Legacy in the ECDFS survey (SIMPLE) and generated a J+Ks selected multi-wavelength catalog including the photometry of both the TENIS near-infrared and the SIMPLE IRAC data. We publicly release the data products derived from this work, including the J and Ks images and the J+Ks selected multiwavelength catalog.Comment: 25 pages, 25 figures, ApJS in pres

DNA Ligase I Is Not Essential for Mammalian Cell Viability

SummaryOf the three DNA ligases present in all vertebrates, DNA ligase I (Lig1) has been considered essential for ligating Okazaki fragments during DNA replication and thereby essential for cell viability. Here, we report the striking finding that a Lig1-null murine B cell line is viable. Surprisingly, the Lig1-null cells exhibit normal proliferation and normal immunoglobulin heavy chain class switch recombination and are not hypersensitive to a wide variety of DNA damaging agents. These findings demonstrate that Lig1 is not absolutely required for cellular DNA replication and repair and that either Lig3 or Lig4 can substitute for the role of Lig1 in joining Okazaki fragments. The establishment of a Lig1-null cell line will greatly facilitate the characterization of DNA ligase function in mammalian cells, but the finding alone profoundly reprioritizes the role of ligase I in DNA replication, repair, and recombination

Urothelial carcinoma in a remnant ureter after a radical nephrectomy for renal cell carcinoma: A case report

AbstractUrothelial carcinoma of a ureteral stump after a radical nephrectomy for renal cell carcinoma is rare. We present the case of a 76-year-old man with painless gross hematuria. The patient had undergone a right nephrectomy for renal cell carcinoma 30 months previously. Cystoscopy showed a blood clot in the right ureteral orifice, and ureteroscopy revealed a papillary mass in the right ureter. The patient underwent a right ureterectomy and bladder cuff resection. The pathology examination showed a high-grade urothelial carcinoma. However, a superficial bladder tumor was discovered postoperatively, and a transurethral resection of the bladder tumor was performed. At 8 months postoperatively, the patient was alive with no evidence of recurrence. A ureteral stump evaluation must be performed when painless hematuria is noted in patients after a nephrectomy

Antimicrobial susceptibility and clinical outcomes of Candida parapsilosis bloodstream infections in a tertiary teaching hospital in Northern Taiwan

BackgroundCandida parapsilosis is an emerging non-albicans Candida that is associated with central line-associated infection. C. parapsilosis has higher minimal inhibitory concentration to echinocandin than Candida albicans, and the effects of echinocandin on C. parapsilosis are ambiguous. Therefore, in this study, we aimed to investigate the susceptibility and the correlation between incidence and drug consumption.MethodsThis retrospective study was conducted in a tertiary teaching hospital in northern Taiwan between 2008 and 2012. The Candida species distribution, the correlation between the use of antifungal agents and the incidence of C. parapsilosis bloodstream infection, demographic information, clinical characteristics, mortality rate, and in vitro susceptibility of C. parapsilosis were analyzed.ResultsA total of 77 episodes from 77 patients were included for analysis. The overall 90-day mortality rate was 41.6%. The incidence of C. parapsilosis bloodstream infection showed a moderate positive correlation with the increased defined daily dose of echinocandin. The risk factors associated with mortality included malignancy or a metastatic tumor. Multivariate logistical regression analysis showed that patients with malignancy had higher odds ratios in terms of mortality. The rate of C. parapsilosis resistance to fluconazole was 3%, whereas the susceptibility rate was 95.5%.ConclusionUnderlying comorbidity and malignancy were factors leading to death in patients with C. parapsilosis bloodstream infection. Catheter removal did not influence the mortality rate. The survival rate of patients receiving echinocandin was lower than the group receiving fluconazole. Fluconazole remains the drug of choice to treat C. parapsilosis bloodstream infections

Dual regulation by ethanol of the inhibitory effects of ketamine on spinal NMDA-induced pressor responses in rats

<p>Abstract</p> <p>Background</p> <p>Acute exposure of ethanol (alcohol) inhibits NMDA receptor function. Our previous study showed that acute ethanol inhibited the pressor responses induced by NMDA applied intrathecally; however, prolonged ethanol exposure may increase the levels of phosphorylated NMDA receptor subunits leading to changes in ethanol inhibitory potency on NMDA-induced responses. The present study was carried out to examine whether acute ethanol exposure influences the effects of ketamine, a noncompetitive NMDA receptor antagonist, on spinal NMDA-induced pressor responses.</p> <p>Methods</p> <p>The blood pressure responses induced by intrathecal injection of NMDA were recorded in urethane-anesthetized rats weighing 250-275 g. The levels of several phosphorylated residues on NMDA receptor GluN1 subunits were determined by western blot analysis.</p> <p>Results</p> <p>Intravenous injection of ethanol or ketamine inhibited spinal NMDA-induced pressor responses in a dose-dependent and reversible manner. Ketamine inhibition of NMDA-induced responses was synergistically potentiated by ethanol when ethanol was applied just before ketamine. However, ketamine inhibition was significantly reduced when applied at 10 min after ethanol administration. Western blot analysis showed that intravenous ethanol increased the levels of phosphoserine 897 on GluN1 subunits (pGluN1-serine 897), selectively phosphorylated by protein kinase A (PKA), in the lateral horn regions of spinal cord at 10 min after administration. Intrathecal administration of cAMPS-Sp, a PKA activator, at doses elevating the levels of pGluN1-serine 897, significantly blocked ketamine inhibition of spinal NMDA-induced responses.</p> <p>Conclusions</p> <p>The results suggest that ethanol may differentially regulate ketamine inhibition of spinal NMDA receptor function depending on ethanol exposure time and the resulting changes in the levels of pGluN1-serine 897.</p

Sampling of basement fluids via circulation obviation retrofit kits (CORKs) for dissolved gases, fluid fixation at the seafloor, and the characterization of organic carbon

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lin, H. T., Hsieh, C. C., Repeta, D. J., & Rappé, M. S. Sampling of basement fluids via circulation obviation retrofit kits (CORKs) for dissolved gases, fluid fixation at the seafloor, and the characterization of organic carbon. Methodsx, 7, (2020): 101033, doi:10.1016/j.mex.2020.101033.The advanced instrumented GeoMICROBE sleds (Cowen et al., 2012) facilitate the collection of hydrothermal fluids and suspended particles in the subseafloor (basaltic) basement through Circulation Obviation Retrofit Kits (CORKs) installed within boreholes of the Integrated Ocean Drilling Program. The main components of the GeoMICROBE can be converted into a mobile pumping system (MPS) that is installed on the front basket of a submersible or remotely-operated-vehicle (ROV). Here, we provide details of a hydrothermal fluid-trap used on the MPS, through which a gastight sampler can withdraw fluids. We also applied the MPS to demonstrate the value of fixing samples at the seafloor in order to determine redox-sensitive dissolved iron concentrations and speciation measurements. To make the best use of the GeoMICROBE sleds, we describe a miniature and mobile version of the GeoMICROBE sled, which permits rapid turn-over and is relatively easy for preparation and operation. Similar to GeoMICROBE sleds, the Mobile GeoMICROBE (MGM) is capable of collecting fluid samples, filtration of suspended particles, and extraction of organics. We validate this approach by demonstrating the seafloor extraction of hydrophobic organics from a large volume (247L) of hydrothermal fluids. • We describe the design of a hydrothermal fluid-trap for use with a gastight sampler, as well as the use of seafloor fixation, through ROV- or submersible assisted mobile pumping systems. • We describe the design of a Mobile GeoMICROBE (MGM) that enhances large volume hydrothermal fluid sampling, suspended particle filtration, and organic matter extraction on the seafloor. • We provide an example of organic matter extracted and characterized from hydrothermal fluids via a MGM.We dedicate this work to Dr. James P. Cowen, who had envisioned and constructed the integrated instrumentation, GeoMICROBE, to monitor the sub-basement biosphere. We thank the chief scientists, captains, crews, and science teams on board R/V Atlantis cruises AT15-35, AT15-51, AT15-66, AT18-07, MSM20-5, AT26-03, and AT26-18, and the pilots and crews of ROV Jason II and HOV Alvin. We thank our student assistants, Natalie Hamada, Kathryn Hu, Ryan Matzumoto, Everette Omori, and Fan-Chieh Chuang. This work was supported by the National Science Foundation-Microbial Observatory Project (NSF-MCB06-04014 to J. P. Cowen), Center for Dark Energy Biosphere Investigations (C-DEBI; NSF award OCE-0939564 to M. S. Rappé), NSF award OCE-1260723 (to M. S. Rappé), and the Ministry of Science and Technology of Taiwan award (MOST 105-2119-M-002-034, MOST 107-2611-M-002-002, MOST 108-2611-M-002-006, and MOST109-2611-M-002-008 to H.-T. Lin). Ministry of Education (MOE) Republic of China (Taiwan) 109L892601 to H.-T. Lin. NSF award OCE-1634080 (to D. J. Repeta), the Simons Foundation-Simons Collaboration on Ocean Processes and Ecology (SCOPE) award 329108 (to D. J. Repeta), the Gordon and Betty Moore Foundation award 6000 (to D. J. Repeta). This paper is SOEST contribution number 11121, HIMB contribution 1804 and C-DEBI contribution number 543

THE EFFECT OF TWO DIFFERENT WEIGHTED BADMINTON RACKETS ABOUT VELOCITY AND TORQUE WHEN OUTSTANDING BADMINTON PLAYERS WAS PERFORMING SMASH MOVEMENT

The purpose of this research is to study and to analyze the relationship of the velocity and torque between two different weighted badminton rackets while the elite players was performing the smash movement .All the data of this study is filmed by digital video (60Hz/s) and is analyzed on the space of 20 by sagittal plane and horizontal axis movement of the participator .In order to derive \rom the primary parameters of smash motion, including velocity, movement of inertia, angular acceleration, torque. The data are digitized and filtered in APAS (the Ariel Performance Analyze System). As a result, by T-Test, the T-values are up to the observable level ,and the level a is 0.05