Common procedures for the detection of specifi c nucleic acids typically involve the exponential amplifi cation of target DNA sequences by using the polymerase chain reaction (PCR) [ 1 ] followed by gel electrophoresis characterization of the amplifi ed DNA molecules. [ 2 ] However, gel-based assays employ tedious procedures and require technical expertise as well as a long analysis time. Real-time PCR techniques, which overcome these problems, are currently widely used for the detection of nucleic acids. These alternatives to gel-based methods enable the simultaneous detection of target DNA during amplifi cation and quantifi cation. [ 3 ] However, since real-time PCR methods still require the availability of specialized reagents (fl uorescent probes or DNA-binding dyes) and expensive instrumentation for monitoring fl uorescence, their application in special environments like point-of-caretesting (POCT) are not possible.Therefore, the development of simpler DNA screening methods that do not require complicated instrumentation would be benefi cial in facility-limited or POCT environments. From this point of view, colorimetric strategies for DNA detection represent attractive approaches since they enable a rapid visual response and do not need sophisticated instrumentation. Consequently, many colorimetric methods that employ conjugated polymers (polythiophene [ 4 ] and polydiacetylene [ 5 ] ) or metal nanoparticles (silver [ 6 ] and gold [ 7 ] ) have been developed recently. Particularly interesting are the extensively studied colorimetric strategies that are based on gold nanoparticles (AuNPs). An important characteristic of these systems is found in the unique color changes that are effected by the transition of AuNPs from dispersed to aggregated states along with a corresponding shift in their surface plasmon absorption spectra. However, the AuNP-based colorimetric methods possess several drawbacks including the fact that the assay is sensitive to salt concentrations, which might lead to incorrect results. Moreover, the existing methods often require laborious premodifi cation of the AuNPs with probe oligonucleotides.Yan et al. recently discovered that magnetic nanoparticles (MNPs), which are generally recognized to be biologically and chemically inert, have an intrinsic peroxidase-like activity that is similar to that of the natural peroxidase enzyme. As a result, MNPs catalyze peroxidase-mediated colorimetric reactions in the presence of H 2 O 2 , generating colored products. [ 8 ] By employing MNPs as peroxidase mimetics, several novel strategies have been developed for the detection of various biological entities, such as cells, proteins and carbohydrates. [ 9 ] In this study, we have devised a new and convenient label-free colorimetric detection method for nucleic acids that employs the peroxidase-mimicking activity of MNPs. To our knowledge, this is the fi rst study of a colorimetric DNA detection procedure that utilizes MNPs.The basic principle involved in the new detection method is schematically display...
Purpose The purpose of this paper is to investigate the mediating effect of practicing core values on the relationship between authentic leadership and work engagement in a Korean corporate environment. Design/methodology/approach Self-report data on authentic leadership, practicing core values, and work engagement were obtained from 281 employees of three major corporations in South Korea. Structural equation modeling was adopted to analyze the data. Findings The results revealed a direct and significant influence of authentic leadership on both practicing core values and work engagement. In addition, practicing core values was found to have a partial mediating effect on the relationship between authentic leadership and work engagement. Research limitations/implications This study revealed a three-factor model of authentic leadership compared to the four-factor model found in western cultural contexts. Similar findings are indicated for other Asian countries. A rigorous future study is warranted to validate the psychometric structure across different cultural settings. Harman’s single factor test was performed to address the common method variance issue. Practical implications Practicing core values functioned as a catalyst for developing authentic leaders. Therefore, it is necessary that organizational development practitioners perform developmental activities to purposefully facilitate practicing core values. Originality/value The study falls under the isolated or disregarded researched topic of the practicing core values in relation to authentic leadership and work engagement.
Apoptosis, a programmed process of cell suicide, has been proposed as the most plausible mechanism for the chemopreventive activities of selenocompounds. In our study, we found that Se-methylselenocysteine (MSC) induced apoptosis through caspase activation in human promyelocytic leukemia (HL-60) cells. Measurements of cytotoxicity, DNA fragmentation and apoptotic morphology revealed that MSC was more efficient at inducing apoptosis than selenite, but was less toxic. Moreover, MSC increased both the apoptotic cleavage of poly(ADP-ribose) polymerase (PARP) and caspase-3 activity, whereas selenite did not. We next examined whether caspases and serine proteases are required for the apoptotic induction by MSC. A general caspase inhibitor, z-VAD-fmk, dramatically decreased cytotoxicity in MSC-treated HL-60 cells and several other apoptotic features, such as, caspase-3 activation, the apoptotic DNA ladder, TUNEL-positive staining and the DNA double-strand break. Interestingly, a general serine protease inhibitor, AAPV-cmk, also effectively inhibited MSC-mediated cytotoxicity and apoptosis. These results demonstrate that MSC is a selenocompound that efficiently induces apoptosis in leukemia cells and that proteolytic machinery, in particular caspase-3, is necessary for MSC-induced apoptosis. On the other hand, selenite-induced cell death could be derived from necrosis rather than apoptosis, since selenite did not significantly induce several apoptotic phenomena, including the activation of caspase-3.
The CYP3A5 genotype of the liver is considered to show the most important association with tacrolimus concentrations. Ultimately, genotyping for CYP3A5 may help optimal individualization of immunosuppressive drug therapy for patients undergoing solid organ transplantation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.