Improved immunodetection of human papillomavirus E7

Human papillomavirus E7 (HPV E7) is a viral oncoprotein that plays an important role in cervical carcinogenesis through binding with retinoblastoma protein (Rb). Inactivation of Rb by E7 is necessary but not sufficient for cellular transformation, suggesting other protein-protein interactions are required for E7-mediated cellular transformation aside from the interaction with Rb. However, studies on the oncogenic function of HPV E7 have been limited by its poor immunoreactivity. In this report, we show that the fixation of purified recombinant HPV E7 on blotted nitrocellulose membrane with glutaldehyde markedly enhanced the immunoreactivity of HPV E7 protein. Using HeLa and Caski cell lines which are infected with HPV 18 and HPV 16, respectively, we demonstrated that native HPV E7 proteins also could be detected by this method. These results therefore can provide the experimental conditions for detection of HPV E7 proteins with greater sensitivity and may help to analyze E7 functions.     

Synthesis and characterization of poly(1,4-phenylenevinylene-alt-2,5-thienylenevinylene) derivatives for organic light-emitting diodes

A new series of alternating copolymers composed of 1,4-phenylenevinylene and 2,5-thienylenylvinylene repeating units with various side chain substituents were synthesized via the Heck coupling reaction for use in light-emitting diodes (LEDs). The resulting copolymers were characterized using ¹H- and ¹³C-NMR, DSC, and TGA. These polymers were found to be soluble in common organic solvents and are easily spin-coated onto glass substrates, producing high optical quality thin films without defects. The electro-optical properties of ITO/PEDOT/Polymer/Al devices were investigated using UV-VIS, PL and EL spectroscopy. The turn-on voltages of these devices were found to be in the range 4-16 V, with a maximum brightness of about 2900 cd/m² at 12 V.     

A two-point in situ method for simultaneous analysis of radioactivity in seawater and sediment

A new in situ radioactivity analysis method was developed to determine the fractional contributions of gamma-ray emitters in seawater and sediment from total measured counts. A semi-empirical formula to determine the fractional count contributions was derived using the variation characteristics of the gamma-ray attenuation rate and geometrical efficiency with the measurement points. The proposed method was employed to make in situ gamma-ray measurements using a CeBr₃ detector for radioactivity analysis of seawater and sediment at a coastal area with a relatively high tidal range. The full energy peak efficiency of the detector at measurement site was obtained using the GEANT4 simulation code. The radioactivity concentration of ⁴⁰K in seawater and sediment was determined using the proposed method and laboratory analysis with sampling. The MDA of the in situ measurement for ¹³⁷Cs and ¹³¹I was also estimated assuming they were deposited on the sediment surface-layer. The validation of this method was demonstrated by comparing with the sampling analysis results.

     

Fabrication of flexible carbon nanotube field emitter arrays by direct microwave irradiation on organic polymer substrate

Carbon nanotubes (CNTs) were directly synthesized on flexible polymer substrates without damage of polymer by microwave irradiation. Cobalt was used as the catalysts, and the synthesis was done in the atmospheric pressure with an acetylene carbon source. Only 5 s was required for the synthesis of well-graphitized CNTs. Field emission measurements revealed that this flexible CNT field emitter array has a great potential for the flexible field emission displays (FEDs).     

In-situ CeBr3 gamma-ray spectrometry for radioactivity analysis of soil

Journal of Radioanalytical and Nuclear Chemistry - A CeBr3 scintillation detector was applied for in situ gamma-ray spectrometry for radioactivity assessment of soil. The full energy peak...     

Biochemical characterizations reveal different properties between CDK4/cyclin D1 and CDK2/cyclin A

CDK2 and CDK4 known promoter of cell cycling catalyze phosphorylation of RB protein. Enzyme specificity between two CDKs that work at a different cell cycle phase is not clearly understood. In order to define kinase properties of CDK2 and CDK4 in complex with cycline A or cycline D1 in relation to their respective role in cell cycling regulation, we examined enzymatic properties of both CDK4/cycline D1 and CDK2/cycline A in vitro. Association constant, Km for ATP in CDK4/cyclin D1 was found as 418 microM, a value unusually high whereas CDK2/cyclin A was 23 microM, a value close to most of other regulatory protein kinases. Turnover value for both CDK4/cyclin D1 and CDK2/cyclin A were estimated as 3.4 and 3.9 min(-1) respectively. Kinetic efficiency estimation indicates far over one order magnitude less efficiency for CDK4/cyclin D1 than the value of CDK2/cycline A (9.3 pM(-1) min(-1) and 170 pM(-1) min(-1) respectively). In addition, inhibition of cellular CDK4 caused increase of cellular levels of ATP, even though inhibition of CDK2 did not change it noticeably. These data suggest cellular CDK4/cyclin D1 activity is tightly associated with cellular ATP concentration. Also, analysis of phosphorylated serine/threonine sites on RB catalyzed by CDK4/cyclin D1 and CDK2/cyclin A showed significant differences in their preference of phosphorylation sites in RB C-terminal domain. Since RB is known to regulate various cellular proteins by binding and this binding is controlled by its phosphorylation, these data shown here clearly indicate significant difference in their biochemical properties between CDK4/cyclin D1 and CDK2/cyclin A affecting regulation of cellular RB function.     

A construction of multiresolution analysis by integral equations

In this paper we present a versatile construction of multiresolution analysis of two variables by means of eigenvalue problems of the integral equation, for . As a consequence we show that if is the solution of the equation with , then constructs a two-variable multiresolution analysis.

     

On-bead expression of recombinant proteins in an agarose gel matrix coated on a glass slide

A system for expression and in situ display of recombinant proteins on a microbead surface is described. Biotinylated PCR products were immobilized on microbead surfaces, which were then embedded in a gel matrix and supplied with translation machinery and substrates. Upon the incubation of the gel matrix, target proteins encoded on the bead-immobilized DNA were expressed and captured on the same bead, thus allowing bead-mediated linkage of DNA and encoded proteins. The new method combines the simplicity and convenience of solid-phase separation of genetic information with the benefits of cell-free protein synthesis, such as instant translation of genetic information, unrestricted substrate accessibility and flexible assay configuration design.