Biomedical subjects

Jin-zhong Chen

Publications and source records attributed to Jin-zhong Chen.

8 recordsLinked to original sources

PubMed2006

DAXX interacts with phage PhiC31 integrase and inhibits recombination.

Phage PhiC31 integrase has potential as a means of inserting therapeutic genes into specific sites in the human genome. However, the possible interactions between PhiC31 integrase and cellular proteins have never been investigated. Using pLexA-PhiC31 integrase as bait, we screened a pB42AD-human fetal brain cDNA library for potential interacting cellular proteins. Among 61 positives isolated from 10(6) independent clones, 51 contained DAXX C-terminal fragments. The strong interaction between DAXX and PhiC31 was further confirmed by co-immunoprecipitation. Deletion analysis revealed that the fas-binding domain of DAXX is also the region for PhiC31 binding. Hybridization between a PhiC31 integrase peptide array and an HEK293 cell extract revealed that a tetramer, 451RFGK454, in the C-terminus of PhiC31 is responsible for the interaction with DAXX. This tetramer is also necessary for PhiC31 integrase activity as removal of this tetramer resulted in a complete loss of integrase activity. Co-expression of DAXX with PhiC31 integrase in a HEK293-derived PhiC31 integrase activity reporter cell line significantly reduced the PhiC31-mediated recombination rate. Knocking down DAXX with a DAXX-specific duplex RNA resulted in increased recombination efficiency. Therefore, endogenous DAXX may interact with PhiC31 causing a mild inhibition in the integration efficiency. This is the first time that PhiC31 was shown to interact with an important cellular protein and the potential effect of this interaction should be further studied.

Adaptor Proteins, Signal Transducing↗

PubMed2005

[Effects of gas composition and pressure on the intensity and quality of the plasma induced by a high-energy neodymium glass laser].

In this experiment, the effects of gas composition and pressure on the intensity and quality of the plasma induced by a high-energy neodymium glass laser were studied. The experimental results show that the spectral intensity of the plasma in the argon atmosphere is stronger than that in the air when the pressure is the same. For the steel alloy sample, the intensities of the emission spectrum reach the maximum values when the argon pressure is 0.8 x 10(5) Pa. The self-absorption phenomena of Al II 308.22 and Al II 309.27 nm lines strengthen with the increase of the pressure, and even serious self-reversal appears when the pressure is (0.8-0.9) x 10(5) Pa. The temperature of plasma also raises with the increase of the pressure. When the argon pressure is 0.93 x 10(5) Pa, t h e temperature is about 1500 K higher than that when the argon pressure is about 0.43 x 10(5) Pa.

Aluminum↗

PubMed2005

[Study on analytic precision of laser microemission spectral analysis in argon atmosphere at reduced pressure].

According to mathematic statistics, data for laser microemission spectroscopic analysis were selected, which were collected with the use of CCD (charge-coupled device) in arg on atmosphere at reduced pressure. By selection, the effects of some factors, such as the difference of bore ablated on the sample surface by the laser, the distribution nonuniformity of element in the sample, and the fluctuation of output energy of the laser, etc. were reduced. The method that improves analytic precision of laser microemission spectroscopic analysis was studied. And quantitative analysis of Cu, Zn and Mg in aluminum alloy standard samples was performed, using the Cu (I) line at 324.7 nm, the Zn (I) line at 334.5 nm, and the Mg (I) line at 383.8 nm. The results show that the RSDs of relative intensity of the spectral lines of Cu, Zn, Mg are 1.80%, 4.35% and 6.29% respectively, and the RSDs of quantitative analysis of them are 10.1%, 6.98% and 8.17% respectively. The relative errors of the average of analysis of them are -3.76%, 3.62% and -1.62% respectively.

Algorithms↗

PubMed2005

[Effect of lens-to-sample distance on laser-plasma radiative properties].

In the present paper, the effect of lens-to-sample distance (LTSD) on the radiative properties from the plasma induced by a high-energy neodymium glass laser (approximately 25J) in the argon ambient gas at a pressure of 0.43 x 10(5) Pa was studied. The experimental results showed that when the focus point of the focusing lens (f = 130 mm) shifts above and below the sample surface, the radiation intensities of the plasma, the excitation temperature, and the mass of ablated material are all changed, and their maxia appear at a focusing location of the laser beam, which is about 0.4 mm under the sample surface for alloyed-steel samples. If soil samples are used as the targets, the emission intensities of the laser plasma and the mass of ablated material have the maxima at a focus position about 0.2 mm below the sample surface. To investigate the influence of LTSD on the shape of the laser plasma, the images of the plasma formed have been shot in argon and air for the alloyed-steel samples. From these results, it was found that the properties of the laser plasma depend strongly on the LTSD.

English Abstract↗

PubMed2004

[Experimental study on laser-induced plasma and its application to spectral analysis].

The article summarizes the progress in the experimental study on laser-induced plasma and its application to spectral analysis domestically and abroad in recent years. It emphatically elaborates the experimental research on the formation, radiation, electron temperature, electron density, and expansion velocity of laser-induced plasma under different conditions (gas composition and pressure, laser energy, laser wavelength, power density and observation height). In addition, in the respect of material composition analysis using the laser-induced plasma, the article mainly interprets two aspects: one is the way to collect directly the plasma emission so as to analyze solid, liquid and gaseous samples, the other is the spectrochemical analysis when laser ablation and ICP are used together. And the article also discusses the factors that influence the precision and the limit of detection.

Clinical Laboratory Techniques↗

PubMed2003

Cloning, expression, and genomic structure of a novel human Rap2 interacting gene (RPIP9).

During a large-scale screen of a human fetal brain cDNA library, a full-length cDNA encoding a novel Rap2 interacting protein was isolated and sequenced. The cDNA is 3397bp long and has a predicted open reading frame encoding a protein of 329 aa. The predicted protein shows high homology to mouse and human RPIP8, and has a RUN domain near its C-terminus. The gene was mapped to human chromosome 7q21-7q22 and has 9 exons and 8 introns. The expression pattern was also detected by cycle-limited reverse polymerase chain reaction (RT-PCR).

Amino Acid Sequence↗

PubMed2003

[Study on the emission spectra of aluminum plasma induced by high energy laser].

The intensities of emission spectra of laser-induced alloy aluminum plasma, with the use of a neodymium glass laser (laser pulse energy is about 25 J), were experimentally studied in argon atmosphere. The effects of atmosphere pressure, height from the observed location of the plasma to the sample surface, operating voltage, and power density of the laser on the signal intensities of emission spectra were discussed. Experimental results showed that the intensities of emission spectra are strongest under 88 kPa of gas pressure. With the increase of the height from the observed location of the plasma to the sample surface, the intensities of emission spectra decrease clearly. At the pressure of 88 kPa and the height of 1.5-2 mm, the emission spectra have maximum intensities. In addition, the spectral line intensities are enhanced significantly with the increase of operating voltage and power density.

Alloys↗

PubMed2002

Cloning, characterization, and expression of calcyphosine 2, a novel human gene encoding an EF-hand Ca(2+)-binding protein.

Calcyphosine is a calcium-binding protein containing four EF-hand domains, initially identified as thyroid protein p24. It was first cloned and its counterparts in rabbit, human, and mouse, crayfish and lobster of invertebrate were also cloned. Here we describe the cloning and characterization of a novel human calcyphosine gene. The 3829-bp cDNA encodes a EF-hand Ca(2+)-binding protein homologous to the dog calcyphosine. It also contains two EF-hand Ca(2+)-binding motif. It is abundantly expressed in many tissues including by RT-PCR analysis and believed to play important role in calcium signaling. It was mapped to human genome 12q15.

Amino Acid Sequence↗