Chromosome 6q deletion mapping in human ovarian tumor: a common deletion region between D6S1649 and D6S311

Objective： To explore the loss of heterozygosity（LOH） on chromosome 6q in ovarian cancer, and localize a minimum area in deletion region. Methods： 93 ovarian tumors were analyzed for LOH studies with 10 microsatellite markers spanning chromosome 6q. To further localize a minimum area in deletion region. Nineteen microsatellite markers were used to refined a minimum area. Results： Forty three tumors （46%） were demonstrated allelic losses, which spanned less than two megabase areas, franked by a distal marker D6S311 and a proximal marker D6S1649, and likely harbored ovarian tumor suppressor gene （s）. With analysis of density of LOH, increased DNA copy number at loci of 6q was demonstrated between D6S1649 and D6S311. Conclusion： It is possible that duplication after the allelic loss might be a main mechanism that leads to carcinogenesis in ovarian tumor. The refinement of these candidate tumor suppressor genes loci might facilitate future loss of heterozygosity studies and enable the isolation of candidate genes from this region.

Establishment of Jurkat tet-on cell line

Tet-control system is developed to tightly control target gene expression in mammalian cells by using the regulatory elements of tetracycline-repressor of the transposor Tn10from E. coli. We have transfected reverse tetracycline-controlled transactivator gene (rtTA) into genome of Jurkat cells and established two Jurkat tet-on celi lines. Induction of luciferase reporter activity with doxycycline, a tetracycline derivative, is dose-dependent with a peak value of 32-fold increment. Establishment of Jurkat tet-on cell lines greatly facilitates guantitative studies on target gene functions in the cells.

Biodegradable films of chitosan and tea polyphenols catalyzed by laccase and their physical and antioxidant activities

The effects of laccase crosslinking chitosan(CS)and tea polyphenols(TP)on the structure,physical and antioxidant properties of CS-based biodegradable films were investigated in this study.Laccase crosslinking significantly increased the particle size and zeta-potential of CS+TP particles.A simple blending of CS and TP decreased the elongation at break significantly,while the elongation at break of biodegradable films significantly increased after laccase crosslinking.Furthermore,TP addition increased the tensile strength(TS)of CS based films,while laccase crosslinking promoted the increase,making it more suitable for application.The addition of TP significantly changed the CS-based films from white and transparent to light brown.NMR spectra showed that no C=N bond was observed in CS+TP particles,which could result from the inhibition of Schiff base reaction due to the big steric hindrance of TP.Right shift of amide I peak to lower wavelength in laccase catalyzed films indicated the conversion of some primary amines into secondary amines caused by Michael addition reaction.It was proposed that laccase oxidized polyphenol to o-quinones,which reacted with nucleophilic groups of chitosan,leading to the increase of secondary amines.Furthermore,the antioxidant capacity of CS+TP films crosslinked by laccase increased significantly compared with CS and CS+TP blended films.In summary,laccase catalysis could be applied to manufacture biodegradable films with improved mechanical property and antioxidant activity.

Cyclic AMP response element binding protein(CREB) participates in the heat-inducible expression of human hsp90β gene

Human heat shock protein 90β gene (hsp90β) is a constitutively expressed heat shock gene existing in most of cell types tested that can be further induced by heat shock. Chloramphenical acetyl transferase (CAT) reporter plasmids driven by different regulatory fragments of hsp90B gene were constructed and transfected into Jurkat cells to explore the role of a cAMP response element (CRE) in the upstream of the gene. Results show that, in comparison with the wild type construct, a severe reduction (~2/3) in the increased folds of promoter activity induced by heat shock at 42℃ for 1 h was observed in a construct with CRE-containing fragment (-173/-91bp) deleted. Electrophoretic mobility shift assays (EMSA) showed that phosphorylated CRE-bindingprotein (CREB) in the nuclear extract of heat shocked Jur-kat cells is specifically bound to the fragment. Additionally, both of the phosphorylation on CREB and the activity of protein kinase A (PKA) were found in Jurkat cells to be enhanced with extending time of

Development of a quantitative RT-PCR system for the specific detection of human heat shock mRNA expression

Heat shock proteins (HSPs), as molecular chaperones, play an important role under physiological condition and in the course of many diseases. It would therefore be valuable to determine the expression of cellular hsp gene quantitatively. Using DNA recombinant technique and in vitro transcription system, a complex internal control RNA has been prepared. After opti-

No prior recognition method of modulation mode by partition-fractal and SVM learning method

A modulation classification method in combination with partition-fractal and support-vector machine(SVM)learning methods is proposed to realize no prior recognition of the modulation mode in satellite laser communication systems. The effectiveness and accuracy of this method are verified under nine modulation modes and compared with other learning algorithms. The simulation results show when the signal-to-noise ratio(SNR) of the modulated signal is more than 8 dB, the classifier accuracy based on the proposed method can achieve more than 98%, especially when in binary phase shift keying and quadrature amplitude shift keying modes, and the classifier achieves 100% identification whatever the SNR changes to. In addition, the proposed method has strong scalability to achieve more modulation mode identification in the future.