Role of Self-Polarization in a Single-Step Controlled Synthesis of Linear and Branched Polymer Nanoparticles

2015 ◽  
Vol 216 (11) ◽  
pp. 1212-1219 ◽  
Author(s):  
Nikunjkumar Visaveliya ◽  
J. Michael Köhler
RSC Advances ◽  
2015 ◽  
Vol 5 (61) ◽  
pp. 49671-49679 ◽  
Author(s):  
Prem. C. Pandey ◽  
Richa Singh ◽  
Yashashwa Pandey

A facile method for the synthesis of functional AgNPs and bimetallic Ag–Au/Au–Ag are reported, enabling the formation of nanocomposite with prussian blue in a crystalline framework for bioanalytical applications, showing the active role of organic reducing agents and 3-aminopropyltrimethoxysilane.


2014 ◽  
Vol 70 (a1) ◽  
pp. C832-C832
Author(s):  
Menico Rizzi ◽  
Riccardo Miggiano ◽  
Samarpita Lahiri ◽  
Giuseppe Perugino ◽  
Maria Ciaramella ◽  
...  

Mycobacterium tuberculosis (MTB) is an extremely well adapted human pathogen capable to survive for decades inside the hostile environment represented by the host's infected macrophages despite exposure to multiple potential DNA-damaging stresses. In order to maintain a remarkable low level of genetic diversity, MTB deploys different strategies of DNA repair, including multi-enzymatic systems, such as Nucleotide Excision Repair, and single-step repair. In particular, to counteract the mutagenic effects of DNA alkylation, MTB performs the direct alkylated-base reversal by sacrificing one molecule of a DNA-protein alkyltransferase, such as O6-methylguanine methyltransferase (OGT; orf: Rv1316c). We present here the biochemical and structural characterization of recombinant mycobacterial OGT (MtOGT) in its wild-type form along with its mutated variants mimicking the ones occurring in relevant clinical strains (i.e. MtOGT-T15S and MtOGT-R37L). Our studies reveal that MtOGT-R37L is severely impaired in its activity as consequence of its ten-fold lower affinity for modified double-stranded DNA (dsDNA) (1). Further investigations on a new structure-based panel of OGT versions, designed to explore different molecular environment at position 37, allowed us a better understanding of the functional role of the MtOGT Arg37-bearing loop during catalysis. Moreover, we solved the crystal structure of MtOGT in covalent complex with modified dsDNA that reveals an unprecedented MtOGT::DNA architecture, suggesting that the MtOGT monomer performing the catalysis needs assisting unreacted subunits during cooperative DNA binding. This work is supported by European Community FP7 program SYSTEMTB (Health-F4-2010-241587)


2014 ◽  
Vol 126 (51) ◽  
pp. 14368-14372 ◽  
Author(s):  
Sheng Deng ◽  
Jian Zhi ◽  
Xianmei Zhang ◽  
Qingqing Wu ◽  
Yun Ding ◽  
...  

2018 ◽  
Vol 21 (3) ◽  
Author(s):  
Marta Musińska ◽  
Marta Minkiewicz ◽  
Justyna Wasielica-Berger ◽  
Krystian Kidrycki ◽  
Krzysztof Kurek

Colorectal cancer is the second most frequently diagnosed cancer in Poland as well as in the world. In addition, this cancer is the second cause of death among oncological diseases. Genetic and environmental factors with a documented impact on the development and progression of colorectal cancer have been thoroughly investigated. Every case of colorectal cancer begins with the stage of a nonmalignant polyp, whose progression to invasive malignant tumor lasts about 10 years. This period is long enough to implement appropriate preventive action that allow early detection and treatment of pre-cancerous lesions. Colorectal cancer screening is the process of detecting polypoid lesions in asymptomatic patients with no history of cancers. Colonoscopy has the benefit of diagnostic and therapeutic tools, which allows to detect and remove of premalignant polyps in a single step approach. The aim of this work is to present the role of a screening program in the prevention of colorectal cancer.


2000 ◽  
Vol 44 (12) ◽  
pp. 3344-3350 ◽  
Author(s):  
Dilek Ince ◽  
David C. Hooper

ABSTRACT Premafloxacin is a novel 8-methoxy fluoroquinolone with enhanced activity against Staphylococcus aureus. We found premafloxacin to be 32-fold more active than ciprofloxacin against wild-type S. aureus. Single mutations in either subunit of topoisomerase IV caused a four- to eightfold increase in the MICs of both quinolones. A double mutation (gyrA and eithergrlA or grlB) caused a 32-fold increase in the MIC of premafloxacin, while the MIC of ciprofloxacin increased 128-fold. Premafloxacin appeared to be a poor substrate for NorA, with NorA overexpression causing an increase of twofold or less in the MIC of premafloxacin in comparison to a fourfold increase in the MIC of ciprofloxacin. The frequency of selection of resistant mutants was 6.4 × 10−10 to 4.0 × 10−7 at twofold the MIC of premafloxacin, 2 to 4 log10 less than that with ciprofloxacin. Single-step mutants could not be selected at higher concentrations of premafloxacin. In five single-step mutants, only one previously described uncommon mutation (Ala116Glu), and four novel mutations (Arg43Cys, Asp69Tyr, Ala176Thr, and Pro157Leu), three of which were outside the quinolone resistance-determining region (QRDR) were found. Genetic linkage studies, in which incross ofgrlA + and outcross of mutations were performed, showed a high correlation between the mutations and the resistance phenotypes, and allelic exchange experiments confirmed the role of the novel mutations in grlA in resistance. Our results suggest that although topoisomerase IV is the primary target of premafloxacin, premafloxacin appears to interact with topoisomerase IV in a manner different from that of other quinolones and that the range of the QRDR of grlA should be expanded.


2019 ◽  
Vol 14 (6) ◽  
pp. 836-846 ◽  
Author(s):  
Bohdan Andreiuk ◽  
Andreas Reisch ◽  
Eduard Bernhardt ◽  
Andrey S. Klymchenko

Blood ◽  
1999 ◽  
Vol 94 (5) ◽  
pp. 1545-1549 ◽  
Author(s):  
Masanori Daibata ◽  
Takahiro Taguchi ◽  
Yuiko Nemoto ◽  
Hirokuni Taguchi ◽  
Isao Miyoshi

Abstract Human herpesvirus 6 (HHV-6) genome has been detected in several human lymphoproliferative disorders with no signs of active viral infection, and found to be integrated into chromosomes in some cases. We previously reported a woman with HHV-6–infected Burkitt’s lymphoma. Fluorescence in situ hybridization showed that the viral genome was integrated into the long arm of chromosome 22 (22q13). The patient’s asymptomatic husband also carried HHV-6 DNA integrated at chromosome locus 1q44. To assess the possibility of chromosomal transmission of HHV-6 DNA, we looked for HHV-6 DNA in the peripheral blood of their daughter. She had HHV-6 DNA on both chromosomes 22q13 and 1q44, identical to the site of viral integration of her mother and father, respectively. The findings suggested that her viral genomes were inherited chromosomally from both parents. The 3 family members were all seropositive for HHV-6, but showed no serological signs of active infection. To confirm the presence of HHV-6 DNA sequences, we performed polymerase chain reaction (PCR) with 7 distinct primer pairs that target different regions of HHV-6. The viral sequences were consistently detected by single-step PCR in all 3 family members. We propose a novel latent form for HHV-6, in which integrated viral genome can be chromosomally transmitted. The possible role of the chromosomally integrated HHV-6 in the pathogenesis of lymphoproliferative diseases remains to be explained.


1988 ◽  
Vol 53 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Barry E. Scheetz ◽  
Christopher M. Stevenson

The role of the theoretical limit of resolution of optical microscopes is discussed in relation to obsidian rim age-date determinations. The resolution of the optics is shown to contribute an error of ± 20 percent. The error analysis identified the determination of the activation energy as the single step in the dating process that introduces the largest error.


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