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Wei-wei Xiao

Publications and source records attributed to Wei-wei Xiao.

6 recordsLinked to original sources

DNA microarray probe preparation by gel isolation nested PCR.

To develop a simplified method that can rapidly prepare DNA microarray probes in a massive scale, a lambda phage genomic DNA-fragments library was constructed for the microarray-probes collection. Four methods of DNA band recovery from the first PCR products were tested and compared. The DNA microarray probes were collected by a novel method of nested PCR that was mediated by gel isolation of the first PCR products. This method was named GIN-PCR. The probes that were prepared by this GIN-PCR technique were used as subjects to fabricate a DNA microarray. The results showed that a wooden toothpick was superior to the other 3 methods, since this technique can steadily transfer the DNA bands as the template of the second PCR after the first PCR. A group of probes were successfully collected and DNA microarrays were constructed using these probes. Hybridization results demonstrated that this technique of DNA recovery and probe preparation was rapid, efficient, and effective. We developed a cost-effective and less labor-intensive method for DNA microarray probe preparation by nested PCR that is mediated by wooden toothpick transfer of the DNA bands in the gel after electrophoresis.

Bacteriophage lambda↗

[Amplification and cloning of the N gene of SARS-associated coronavirus].

OBJECTIVE: To amplify and clone the N gene of severe acute respiratory syndrome-associated coronavirus. METHOD: Using primer Premier 5.0 software, two pairs of nested PCR primers were designed to amplify the N gene. After purification, the amplified products were cloned into pMD18-T vectors, and the positive clones with the inserted fragments were identified by sequence analysis. RESULTS: The amplified products was about 1 375 bp in length, and sequence analysis demonstrated that the N gene fragments had been successfully inserted into pMD18-T vectors. CONCLUSION: The successful amplification and cloning of N gene facilitates further investigation of the expression of the N protein and study of its structure and functions.

Base Sequence↗

Design and preparation of oligonucleotide microarray for vaccinia virus detection.

OBJECTIVE: To study the preparation of oligonucleotide microarray for detecting vaccinia virus. METHODS: Oligonucleotide probes were designed and synthesized according to the specific genes of vaccinia virus. Sample DNA of the virus and the negative control sample were obtained and labeled by restriction display technique, followed by hybridization to the oligonucleotide microarray and scanned by Agilent scanner. RESULTS: Strong hybridization signals were detected from the viral DNA hybridized with the microarray, but were absent in the negative sample when positive probes were not used. CONCLUSION: Distinct differences in the hybridization signals between the virus sample and negative sample and between the samples obtained in different phase of infection demonstrate high specificity and sensitivity of the microarray for vaccinia virus detection.

Base Sequence↗

[Gene sequence analysis of SARS-associated coronavirus by nested RT-PCR].

OBJECTIVE: To explore an effective means for the detection of Severe Acute Respiratory Syndrome (SARS)- associated coronavirus. METHODS: The RNAs of the virus contained in the sputum samples from established SARS patients were extracted and reversely transcripted, followed by nested PCR using the reversely transcripted cDNA as the template. The PCR products were cloned then into the pMD18-T vectors, followed by sequence analysis. RESULTS: Specific fragments were amplified from the sputum samples of SARS patients, which were confirmed by DNA cloning and sequencing to belong to SARS-associated coronavirus. The Result of Blast shows only the difference in one nucleic acid from the TOR2 strain of SARS-associated coronavirus. CONCLUSION: Sequence analysis has confirmed the existence of SARS-associated coronavirus in the sputum samples of SARS patients, and nested RT-PCR is a quick, easy, and convenient way for the detection of the virus.

Base Sequence↗

[Preparation of gene chip probes for Bacillus anthracis protective antigen].

OBJECTIVE: To study the method for rapid preparation of the gene chip probes for Bacillus anthracis protective antigen (pag). METHODS: According to the sequences of pag published on PubMed, a pair of primers was designed to amplify the PA gene of Bacillus anthracis. Restriction enzyme digestion and AT clone were employed to rapidly screen out the recons of PA segments for the preparation of the gene chip probes. The DNA sequences of these segments were determined with 377 DNA Sequencer, and the resultant sequences analyzed with Bioinformatic software. RESULTS: With the designed primers, the pag 2,205 bp in length was amplified. After enzyme digestion and AT clone, 7 fragments of varied lengths were screened, which underwent analysis with the basic local alignment sequence tool (BLAST) and 377 DNA Sequencer. BLAST analysis showed that all the fragments cloned belonged to Bacillus anthracis. CONCLUSION: PCR in conjunction with restriction enzyme digestion and AT clone is rapid and simple to prepare the desired gene chip probes.

Antigens, Bacterial↗

[Bioinformatic analysis of dengue virus cDNAs and design of oligonucleotide probes for microarray detection of the virus].

OBJECTIVE: To design oligonucleotide probes for microarray detection of dengue virus. METHODS: By analyzing the cDNAs of dengue viruses of 4 different serotypes with BLAST program, a group of specific sequences for the candidate probes was acquired. Oligo6.0 software was applied to analyze the candidates to select the probes with high specificity, identical length and similar melting temperature (Tm). RESULT: Altogether 48 oligonucleotide probes were designed, and deposited on oligonucleotide chips as the microarray for dengue virus detection. CONCLUSION: BLAST program and Oligo6.0 software are simple and effective means for designing the oligonucleotide probes.

Base Sequence↗