Sheng wu hua xue yu sheng wu wu li xue bao Acta biochimica et biophysica Sinica最新文献

The dynamic features of rat EEGs collected during slow wave sleep (SWS) and transition sleep (TS) were investigated in both time and frequency domains using wavelet transform based on multi-resolution signal decomposition. EEGs of freely moving rats were recorded with implanted electrodes and then decomposed into four components of delta, theta, alpha and beta using wavelet transform. The power and power percentage of each component were calculated as functions of time. In SWS EEGs, the results showed that there existed as much as 26.2% +/- 7.7% time duration in which the delta power percentage was less than 50%. In addition, the powers of other three components in small delta EEGs were significantly larger than those in large delta EEGs. This result revealed a reciprocal relationship between delta oscillation and spindle oscillation. Comparatively, the conventional method of FFT based power spectrum could only show a delta power-dominating (70.6% +/- 6.4%) spectrum of SWS EEGs. In the non-stationary TS EEG, spindle and non-spindle segments were distinguished based on the wavelet components of theta and alpha, and then the average duration of the spindles was estimated. In conclusion, the wavelet transform may be useful in developing novel quantitative time-frequency measures of sleep EEGs as valuable complements of conventional FFT method to analyze the transient changes in sleep EEGs induced by physiological, pathological or pharmacological conditions.

A full-length Ty3-like retrotransposon, named RIRE10, was identified on the long arm of chromosome 4 in rice genome. The internal region between two LTRs had another open reading frame in the region upstream of gag-pol sequence. The transcripts from LTR region were detected by Northern blot hybridization and RT-PCR. To assess the activity of RIRE10 in rice genome, the copy number of its internal region and long terminal repeat (LTR) domain were determined by dot blot analyses. Nearly 900 solo-LTR of the RIRE10 retrotransposon exist in rice genome, apart from those LTRs that flank 65 intact RIRE retrotransposons. Based on the experimental results, the retrotransposition of RIRE10 was speculated to be influenced by two factors: transcriptional activity of LTR region and homologous recombination resulting in solo-LTR.

Recent studies have shown that there are geographic variation of alpha-neurotoxins in Naja kaouthia, but the cause is not clear yet. In this work, venoms were collected from adult Naja atra in Zhejiang Province and Naja kaouthia in Yunnan Province, well identified by morphological characters and cytochrome b gene analysis in summer season to avoid age and seasonal variation in the venom composition. Then alpha-neurotoxins were purified and cloned from these two kinds of snakes. Three alpha-neurotoxins from Naja kaouthia (Yunnan) and two from Naja atra (Zhejiang) were identified. Together with previously reported alpha-neurotoxins in Naja kaouthia (Thailand) and Naja atra (Taiwan Province), it was found that the alpha-neurotoxins of Naja kaouthia in Yunnan Province were similar to those of Naja atra in Zhejiang and Taiwan Provinces, but different from those of Naja kaouthia in Thailand. This result can hardly be explained by population phylogeny or geographic distance. It might be due to the different climate, habitat and prey in Thailand in comparison with those in Yunnan, Zhejiang and Taiwan Provinces.

The gene C17orf25 was isolated from the liver by RACE PCR. nudt9 gene was screened by yeast two-hybrid method in MatchMaker human HeLa cDNA library. NUDT9 is an enzyme that has pyrophosphatase activity with ADP-ribose as its substrate. Fusion expression of C17orf25 and GFP and computer analysis showed that C17orf25 was probably located in mitochondria. Furthermore, C17orf25 may suppress the cell growth by interaction with NUDT9.

A novel coronavirus (SARS-coronavirus, SARS-CoV) was discovered in association with cases of severe acute respiratory syndrome (SARS) recently. The first step in coronavirus infection is binding of the viral spike protein to certain receptor on host cells. The spike protein is the main surface antigen of the coronavirus and there should be antibodies against spike protein in patients serum. Thus, to develop and expression protein fragment from spike protein gene are the purposes of this experiment. Partial spike gene fragments (751-1925 bp, 2005-3410 bp, 1-1925 bp and 32-3659 bp) and its intact gene were cloned into pET32 or pGEX vectors, and transformed into competent Escherichia coli BL21(DE3) (pLysS), respectively. 63, 78, 98, 160 and 164 kD fusion proteins were successfully expressed with amounts of 35%, 34%, 24%, 17% and 5% of total cell protein. The soluble parts of the cell crude extract were then partially purified by GST affinity chromatography.

To explore the approaches and mechanisms for reversing the immune tolerance in transgenic mouse, and the pathogenicity of hepatitis G virus (HGV), the promoter of phoP-activated gene (P(pagC)) of Salmonella typhimurium was used as a transcriptionally regulating element to construct an attenuated S. typhimurium expressing HGV NS3. The recombinant S. typhimurium was orally administered to HGV transgenic mice. As the results, HGV antigen in serum and liver as well as HGV mRNA in liver were decreased significantly, although the serum anti-HGV NS3 remained undetectable as the control transgenic mice. The spleen cell proliferation, in vitro HGV NS3 specific CTL, and IFN-gamma assays with the primed cultured splenocytes indicated the induction of Th1 immune responses in those administered transgenic mice. Adoptive transfer of fractionated primed spleen cells to the transgenic mice showed that T lymphocytes were responsible for, maybe through IFN-gamma, the down-regulation of HGV mRNA transcription. Histological examination found no significant inflammatory changes in liver of the transgenic mice. These findings suggested that the oral inoculation of the HGV NS3-expressed attenuated S. typhimurium driven by an in vivo-activated promoter should be a simple and effective approach for potential treatment of chronic viral infection.

This report aimed at investigation on the application of atomic force microscope (AFM) in research on interaction between cells and extracellular matrix, and function of extracellular matrix. Distribution and array of fibronectin fibrils surrounding human breast carcinoma MCF-7-R cells were observed by atomic force microscope, and comparison of AFM with other traditional techniques was performed. Whole and local AFM morphological images of several human breast carcinoma MCF-7-R cells and fibronectin fibrils around cells were obtained by AFM. Distribution and array of fibronectin fibrils were found to be very regular, and the regulated array coordinated with functions of fibronectin fibrils very well. Owing to advantages of simple sample preparation and very high resolution, AFM is an ideal tool to in situ observation of extracellular matrix.

A cDNA encoding mouse implantation serine proteinase 2 ISP2 was amplified from total cDNAs of mouse uterus implantation sites on D4.5 of pregnancy by PCR, and sequenced GenBank accession No. A442918 . DNA sequencing indicated that the ISP2 cDNA had an unreported 204 bp sequence at 3' untranslated region besides the open reading frame encoding 279 amino acid residues, which was identical with literature. In order to obtain recombinant ISP2 rISP2 an expression plasmid pGEX-4T-2/ISP2 was constructed and transformed into E.coli BL21(DE3) strain. Expressed fusion protein GST-ISP2 was purified by SDS-PAGE and digested with thrombin, and the digestion mixture was subjected to SDS-PAGE again to recover rISP2. Rabbits were immunized using rISP2 as immunogen, and the polyclonal anti-ISP2 antisera were obtained. Immunohistochemical analysis using this antisera showed specific and high expression of ISP2 in mouse endometrial gland epithelium in early pregnancy.

The unfolding of 23kD (P23k) protein isolated from spinach photosystem II particle was studied by high pressure and fluorescence spectroscopy. The thermal equilibrium study indicated that the protein could be totally unfolded by 180 or 160 MPa at 20 degrees C and 3 degrees C, respectively. The standard free energy and standard volume change of the protein for unfolding at 20 degrees C is 23.45 kJ/mol and -150.3 ml/mol, respectively. Kinetics study indicated that at 20 degrees C the activation volume for unfolding, delta V(u)(++), was negative (-66.2 ml/mol), meanwhile the activation volume for folding, deltaV(f)(++), was positive (84.1 ml/mol). The rate constants for folding and unfolding (K(0f), K(0u)) were 1.87 s(-1) and 1.3x10(-4) s(-1), respectively, these results provide some clues to explain why the protein is so sensitive to pressure.

Two-dimensional polyacrylamide gel electrophoresis is one of the most key separation tools which can reveal hundreds or even thousands of proteins at a time in proteomic research. In this paper, we report a new IPG strip application, called multi-strips on one gel (MSOG) method. By comparing the 2-DE patterns of the same sample, the different state samples and the same sample in the different second dimensional SDS running systems (large size and medium size gels), we found this new method can not only improve the reproducibility and resolution power of 2-DE pattern, but also achieve high throughput and economical format which is helpful to automatic proteomic research.