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Bin Zhou

Publications and source records attributed to Bin Zhou.

At least 55 records · Page 3Linked to original sources
PubMed2005

Stereophysicochemical variability plots highlight conserved antigenic areas in Flaviviruses.

BACKGROUND: Flaviviruses, which include Dengue (DV) and West Nile (WN), mutate in response to immune system pressure. Identifying escape mutants, variant progeny that replicate in the presence of neutralizing antibodies, is a common way to identify functionally important residues of viral proteins. However, the mutations typically occur at variable positions on the viral surface that are not essential for viral replication. Methods are needed to determine the true targets of the neutralizing antibodies. RESULTS: Stereophysicochemical variability plots (SVPs), 3-D images of protein structures colored according to variability, as determined by our PCPMer program, were used to visualize residues conserved in their physical chemical properties (PCPs) near escape mutant positions. The analysis showed 1) that escape mutations in the flavivirus envelope protein are variable residues by our criteria and 2) two escape mutants found at the same position in many flaviviruses sit above clusters of conserved residues from different regions of the linear sequence. Conservation patterns in T-cell epitopes in the NS3- protease suggest a similar mechanism of immune system evasion. CONCLUSION: The SVPs add another dimension to structurally defining the binding sites of neutralizing antibodies. They provide a useful aid for determining antigenically important regions and designing vaccines.

Amino Acid Motifs↗
PubMed2005

[The roles of complement 1q and anti-C1q autoantibodies in pathogenesis of lupus nephritis].

OBJECTIVE: To analyze the correlation of serum levels of complement 1q (C1q) and anti-C1q autoantibodies (C1qAb) with renal pathology in lupus nephritis (LN) and to explore the probable mechanism of C1q and C1qAb in the development of systemic lupus erythematosus (SLE), especially LN. METHODS: The serum samples of 80 SLE patients, 40 LN patients and 40 non-LN patients, were collected to detect the level of C1q with single radial immunodiffusion and the level of C1qAb with enzyme-linked immunosorbent assay. Renal biopsy was conducted in 25 of the 32 LN patients so as to observe the deposition of apoptotic cells and apoptotic bodies in the glomeruli with TdT-mediated dUTP nick end labeling. RESULTS: The serum level of C1q was (130 +/- 50) mg/L in the LN patients, significantly lower than that in the non-LN patients [(170 +/- 70) mg/L, P = 0.004]. The serum level of C1qAb (P/N value) was 7 +/- 4 in the LN patients, significantly higher than that in the non-LN patients (4 +/- 3, P < 0.001). The correlation coefficient between C1qAb and C1q in the LN patients was -0.567 (P < 0.01), showing a significant negative correlation. The correlation coefficient between C1qAb and C1q in the non-LN patients was -0.509 (P = 0.001), showing a significant negative correlation. The serum C1q level of the type IV LN patients was significantly lower than that in the type I LN patients, and the serum C1qAb level of the type IV LN patients was significantly higher than that in the type I LN patients (P < 0.05). The serum C1q was significantly lower in the LN patients with renal C1q deposition (++) than in the LN patients with renal C1q deposition (+), however, the serum C1qAb was significantly higher in the LN patients with renal C1q deposition (++) than in the LN patients with renal C1q deposition (+) (both P < 0.05). The serum C1q level was significantly lower in the LN patients with positive IgG deposition than in the LN patients with negative IgG deposition and the serum C1qAb level was significantly higher in the LN patients with positive IgG deposition than in the LN patients with IgG negative deposition (both P < 0.05). The serum C1q level in the LN patients with positive C3 deposition was significantly lower than that in the LN patients with negative C3 deposition (P < 0.05). The serum C1q level in the LN patients with marked apoptotic cells and deposition of apoptotic bodies was significantly lower than that in the LN patients without marked apoptotic cells and deposition of apoptotic bodies, and the serum C1qAb level in the LN patients with obvious apoptotic cells and deposition of apoptotic bodies was significantly higher than that in the LN patients without obvious apoptotic cells and deposition of apoptotic bodies (both P < 0.05). The decrease of serum C1q level and increase of serum C1qAb were significantly positively correlated with the deposition of C1q, IgG, and C3 in the kidney, and with the appearance of apoptotic cells and deposition of apoptotic bodies in the kidney. CONCLUSION: C1q and C1qAb may be involved in the pathogenesis of SLE, especially LN. The probable mechanism may be that they promote renal deposition of circulating immune complexes combined with C1q or promote the renal deposition of apoptotic cells and apoptotic bodies.

Adult↗
PubMed2005

Characterization of Nfatc1 regulation identifies an enhancer required for gene expression that is specific to pro-valve endocardial cells in the developing heart.

Nfatc1 is an endocardial transcription factor required for development of cardiac valves. Herein, we describe identification and characterization of a tissue-specific enhancer in the first intron of murine Nfatc1 that activates a heterogenic promoter and directs gene expression in a subpopulation of endocardial cells of the developing heart: the pro-valve endocardial cells. This enhancer activity begins on embryonic day (E) 8.5 in endocardial cells at the ventricular end of the atrioventricular canal, intensifies and extends from E9.5 to E11.5 in endocardium along the atrioventricular canal and outflow tract. By E12.5, the enhancer activity is accentuated in endocardial cells of forming valves. Sequential deletion analysis identified that a 250 bp DNA fragment at the 3' end of the intron 1 is required for endocardial-specific activity. This region contains two short conserved sequences hosting a cluster of binding sites for transcription factors, including Nfat and Hox proteins. Electrophoresis mobility shift and chromatin immunoprecipitation assays demonstrated binding of Nfatc1 to the Nfat sites, and inactivation of Nfatc1 downregulated the enhancer activity in pro-valve endocardial cells. By contrast, mutation of the Hox site abolished its specificity, allowing gene expression in non pro-valve endocardium and extracardiac vasculature. Thus, autoregulation of Nfatc1 is required for maintaining high Nfatc1 expression in pro-valve endocardial cells, while suppression through the Hox site prevents its expression outside pro-valve endocardial cells during valve development. Our data demonstrate the first autonomous cell-specific enhancer for pro-valve endocardial cells and delineate a unique transcriptional mechanism that regulates endocardial Nfatc1 expression within developing cardiac valves.

Animals↗
PubMed2005

Molego-based definition of the architecture and specificity of metal-binding sites.

Decomposing proteins into "molegos," building blocks that are conserved in sequence and 3D-structure, can identify functional elements. To demonstrate the specificity of the decomposition method, the PCPMer program suite was used to numerically define physical chemical property motifs corresponding to the molegos that make up the metal-containing active sites of three distinct enzyme families, from the dimetallic phosphatases, DNase 1 related nucleases/phosphatases, and dioxygenases. All three superfamilies bind metal ions in a beta-strand core region but differ in the number and type of ions needed for activity. The motifs were then used to automatically identify proteins in the ASTRAL40 database that contained similar motifs. The proteins with the highest PCPMer score in the database were primarily metal-binding enzymes that were related in function to those in the alignment used to generate the PCPMer motif lists. The proteins that contained motifs similar to the dioxygenases differed from those found with PCP-motifs for phosphatases and nucleases. Relatively few metal-binding enzymes were detected when the search was done with PCP-motifs defined for interleukin-1 related proteins, which have a beta-strand core but do not bind metal ions. While the box architecture was constant in each superfamily, the specificity for the metal ion preferred for enzymatic activity is determined by the pattern of carbonyl, hydroxyl or imadazole groups in key positions in the molegos. These results have implications for the design of metal-binding enzymes, and illustrate the ability of the PCPMer approach to distinguish, at the sequence level, structural and functional elements.

Binding Sites↗
PubMed2005

Multi-dysfunctional pathophysiology in ITP.

Idiopathic thrombocytopenic purpura (ITP) is an organ-specific autoimmune disorder characterized by a low platelet count and mucocutaneous bleeding. The decrease of platelets is caused by increased autoantibodies against self-antigens, particularly IgG antibodies against GPIIb/IIIa. The production of these autoantibodies by B cells depends on a number of cellular mechanisms that form a network of modulation, with T cells playing a pivotal role in pathophysiology. Delineation of the dysfunction of cellular immunity has recently been attempted. This review will focus on these recent advances applicable to ITP and to highlight how these may translate into novel approaches to treatment in the future. Multi-dysfunction in these networks may include a failure of self-antigen recognition and tolerance, involvement of abnormal cell surface molecules, altered Th1/Th2 cytokine profiles, impaired megakaryocytopoiesis and impaired cell-mediated cytotoxicity. In ITP, multi-step dysfunctions in these networks may take place that finally lead to the occurrence of the disease. Therefore, unveiling these dysfunctions is vital in understanding the pathophysiology of ITP and will finally lead to the development of new therapies to fight the disease.

Cell Communication↗
PubMed2005

[A multiplex for simultaneous amplification of three Y-STR loci using modified primers].

OBJECTIVE: To develop a multiplex method for simultaneous detection of Y-STR loci. METHODS: The primers of Y-STR loci were devised for use in the simultaneous amplification of three Y-STR loci (DYS390, DYS391, DYS393). RESULTS: Simultaneous amplification of the three Y-STR loci was successfully performed using the modified primers in which the fragment length of DYS391 was shortened from 279-287 bp to 142-150 bp, and at the same time, the virile specificity of DYS393 was enhanced. CONCLUSION: The use of new-devised primers of Y-STR loci is a valid approach to rapid detection of multiple Y-STRs loci; it is worthy to be recommended in the field of forensic science.

Chromosomes, Human, Y↗
PubMed2005

[Characterization of murine leukemia virus recombinants that express H5N1 subtype avian influenza virus hemagglutinin glycoproteins].

One highly pathogenic strain of avian influenza virus (AIV) was isolated from goose in China recently, designated as F-3. In order to study the viral entry mechanisms, the hemagglutinin (HA) gene of H5N1 subtype AIV isolate was amplified by RT-PCR, and then cloned into pGEM-T vector and sequenced. The sequencing result has logging in GenBank, the accession number was AY639405. The HA gene of F-3 had a complete open reading frame (ORE) and composed of 1707 nucleotides, coding for 568 amino acids. The deduced amino acid sequence at the cleavage site of the HA protein was RKKR GLF, matched to the characteristic of virulent avian influenza strain. The HA gene were subcloned into pcDNA3, so the plasmid pcDNA-HA can express the HA glycoprotein. Co-transfected pcDNA-HA, pHIT60 (include Murine Leukemia Virus structural genes, namely gag and pol) and pHIT111 (retroviral vector genome,containing LacZ as a reporter) into 293T cells. The retroviral supernatant were harvested 48 hours post-transfection, filtered through 0.45 micromol/L filter. The supernatant were used to analysis the characteristic of the pseudotyping virions by Western blotting and infection test. Western blotting revealed the HA glycoproteins can be expressed on the virions, indicated the glycoproteins were incorporated onto the retroviral virions. Infection test were performed on 293T, NIH3T3 and COS-7, all the three kinds of cells infected were lacZ positive, indicating viral entry, and revealed the pseudotype virions of MuLV-HA were infectious. So the pseudotype system of MuLV particles with AIV Hemagglutinin proteins were setted up and it can be used to study the entry of avian influenza virus isolated from goose in China.

Animals↗
PubMed2005

[The distribution of fimA genotype of Porphyromonas gingivalis in chronic periodontitis patients].

OBJECTIVE: To investigate the distribution of fimA genotype of P. gingivalis in chronic periodontitis patients. METHODS: Subgingival plaque samples were collected from 101 chronic periodontitis patients. P. gingivalis was detected by both culture method and P. gingivalis 16S rRNA PCR. fimA type-specific primer were designed, and the distribution of fimA genotype of P. gingivalis in periodontitis patients were detected by PCR. RESULTS: The detective ratio of P. gingivalis was 88.1%. Among them, a single fimA genotype was detected in most subgingival plaque samples (65.1%), and the distribution of five fimA genotypes among P. gingivalis positive patients was as follows: type I, 24.7%; type II, 43.8%; type III, 15.7%; type IV, 40.4%; type V, 3.4%; respectively. CONCLUSION: P. gingivalis with various fimA genotypes were present in subgingival plaque samples from chronic periodontitis patients, and P. gingivalis with type II fimA and IV fimA were more predominant in chronic periodontitis patients, and they may be associated with the development of periodontitis.

Adult↗
PubMed2005

[Modification of hybrid antimicrobial peptide CecA-mil gene and its over-secretion expression in Pichia pastoris].

According to the partiality codon of Pichia pastoris, hybrid antimicrobial peptide CecA-mil gene was reconstructed, synthesized and cloned into pPICZalpha-A to construct the recombinant expression vector pPICZa-A-CM. The pPICZalpha-A-CM was transformed into yeast host strain X-33. Under the control of the promoter AOX1 (alcohol oxidase 1), a approximately 1.9 kD cecA-mil protein was expressed with the high level of 245 microg/mL after optimized the requirements for the flask-shaking culture fermentation of the Pichia pastoris rX-33/pPICZalpha-A-CM. The hybrid antibacterial peptide had a broad spectrum antibacterial activity on both gram-positive and gram-negative bacteria, especially showed potent antibacterial activity against ampicillin-resistant and kanamycin- resistant bacteria, such as Staphylococcus aureus (cowan I) and pathogenic E. coli (O1) from chicken. In addition, the hybrid antibacterial peptide showed an extreme heat-stable and acid-stable characteristic. Based on these characteristics, the recombinant antibacterial peptide CecA-mil display application foreground in the field of antisepsis of food, prevention of disease, additives of animal feedstuff and so on.

Anti-Infective Agents↗
PubMed2005

[Method for human peripheral blood eosinophil isolation for patch-clamp study].

OBJECTIVE: To establish a rapid and economic method for isolating human peripheral blood eosinophils with high viability for patch-clamp studies and investigate the electrophysiological properties of Ca(2+)-activated K(+) channel of the isolated cells. METHODS: Peripheral blood eosinophils were isolated by modified discontinuous Percoll density gradient centrifugation, and the electric currents in the single Ca(2+)-activated K(+) channels of the cells were recorded using patch-clamp technique with cell-attached configuration. RESULTS: The purity of the eosinophils from healthy donors reached (90.5+/-1.6)%, with a viability rate over 99% and recovery rate of (48.2+/-6.9)%. The isolated cells were morphologically intact, from which Ca(2+)-activated K(+) channel activity could be detected. CONCLUSION: The peripheral blood eosinophils isolated using this rapid, simple and highly efficient method are characterized by high purity and viability without obvious cellular injuries, which are ideal for patch-clamp studies.

Cell Separation↗