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Biomedical subjects

X F Wu

Publications and source records attributed to X F Wu.

44 records · Page 3Linked to original sources
PubMed1985

A clone of hepatitis B virus (subtype adr) DNA with a new HindIII site.

We have cloned the HBV genome subtype adr through its HindIII site into plasmid pBR322. Twelve recombinant plasmids each with an insert of the HBV genome were obtained. The restriction map of one of the recombinants, plasmid pADR-H1, was analyzed. The location of the sites for BamHI, BglI, BglII, SstII, XbaI and XhoI in pADR-H1 were found to be the same as that in pADR-1, but the HindIII site of pADR-H1 is distinctly different from that of pADR-1. The BamHI-HindIII fragment is 316 bp long in the genome of pADR-1. However, it is only 82 bp in pADR-H1. No deletion of sequence between BamHI and HindIII sites has been found in the HBV genome of pADR-H1. The sequencing data around the HindIII site of pADR-H1 in both pADR-H1 and pADR-1 showed that there is a stretch of AAGTTT in pADR-1 compared to an AAGCTT in pADR-H1. In addition, other differences were found. There are three sites for AvaI, four for HincII, one for HpaI and none for SphI in the genome of pADR-H1 compared to four sites for AvaI, three for HincII, one for SphI and none for HpaI in pADR-1. The biological significance of base pair mutation in HBV DNA and the possibility of the existence of HindIII site in the genome of subtypes ayw and adw were discussed.

Base Sequence↗
PubMed1984

Classification of Agkistrodon species in China.

The wide geographical distribution of Agkistrodon and the slight morphological differences among the snakes of the genus Agkistrodon in China have posed a problem to taxonomists. We have employed polyacrylamide gel electrophoresis and immunological diffusion techniques for comparison of the venoms of different species and subspecies of Agkistrodon from various localities. The electrophoretic patterns of the proteins of the venoms were different from each other, but showed certain relations within species and subspecies. We used Ouchterlony double diffusion of a rabbit antiserum against the purified "neurotoxin" from the venom of Agkistrodon blomhoffii brevicaudaus (from the Zhejiang Province of China) on the various venoms of Agkistrodon. Precipitin lines formed with immunological identity between the same species, partial identity between closely related species and no precipitin line between different species. Combining experimental data, morphological characteristics and geographical distribution, we propose that the genus Agkistrodon (sensu stricto) in China consists of seven species and subspecies: (1) Agkistrodon blomhoffii brevicaudus Stejneger, (2) A. b ussuriensis Emelianov, (3) A. intermedius (Strauch), (4) A. saxatilis Emelianov, (5) A. shedaoensis Zhao, (6) A. strauchii Bedriaga, (7) A. monticola Werner. Agkistrodon acutus (Guenther) has recently been changed to a new genus, Deinagkitrodon, established by Gloyd in 1978.

Animals↗
PubMed1983

Cloning and restriction mapping of human HBV genome serotype adr.

A Bam HI cleaved 3.2 Kb fragment from the HBV adr genome was cloned in E. coli using pBR322 as vector. Sixteen restriction sites from the action of Bam HI, Hind III, Bgl I, Bgl II, Ava I, Hinc II, Sph I, Xba I, Xho I and Sst II were determined and mapped. No cleavage sites were found for Eco RI, Pst I, Sma I, Hpa I, Kpn I, Pvu II and Sst I. The restriction map for HBV adr is significantly different from those reported for the subtypes adw, ayw and adyw.

Cloning, Molecular↗
PubMedDate not supplied

Gene cloning, expression and vaccine testing of Schistosoma japonicum SjFABP.

A 600 bp DNA fragment was amplified by PCR from an adult Schistosoma japonicum cDNA library. Sequence analysis confirmed that this fragment contained an S. japonicum Chinese mainland strain fatty acid binding protein (Sj14FABP) gene. This gene was subsequently expressed in Escherichia coli (E. coli) and in Baculovirus/silkworm systems. The recombinant protein from E. coli was a 41 kDa GST fusion protein (rSj14/GST), which could be purified by glutathione agarose affinity chromatography, with a yield of 25 mg/L E. coli culture. The recombinant protein from the Baculovirus/silkworm system was an 18 kDa fusion protein (rSj14/His), which could be purified by Ni-NTA resin chromatography column with a yield of 3.5 mg per silkworm larva. Both rSj14/GST and rSj14/His could be recognized by S. japonicum-infected mouse sera and anti-rSj14/GST mouse sera in Western blotting. The purified recombinant protein was immunogenic in mice, rats and sheep, and 34.3%, 31.9% and 59.2% worm reductions, respectively, were obtained in vaccinated Kunming mice, Wistar rats and sheep vaccinated with Sj14/GST, compared to non-vaccinated control groups. Worm reductions of 48.8% and 49.0% were recorded in Balb/c mice immunized with Sj14/His, compared to non-vaccinated and BCG-vaccinated groups, respectively. These results indicate that rSj14FABP is a promising candidate vaccine for schistosomiasis japonica, particularly as in the rat and sheep vaccination experiments, no adjuvant was used.

Amino Acid Sequence↗
PubMedDate not supplied

The 80L5C4 epitope overlaps with the homophilic binding site of the cell adhesion molecule gp80 of Dictyostelium.

The monoclonal antibody (mAb) 80L5C4 is a potent inhibitor of the cell adhesion molecule gp80 of Dictyostelium discoideum. To map the exact location of the epitope recognized by mAb 80L5C4, overlapping hexapeptides were synthesized on plastic pins and the binding p6 mAb 80L5C4 to these peptides was monitored by enzyme-linked immunosorbent assay. The 80L5C4 epitope is mapped to a single hexapeptide sequence GYKLNV, which shares five amino acid residues with the octapeptide sequence YKLNVNDS involved in gp80 homophilic binding. Analogue studies indicate that the hydrophobic residues within this sequence are crucial for antigen recognition.

Amino Acid Sequence↗