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K Y Liu

Publications and source records attributed to K Y Liu.

27 records · Page 2Linked to original sources
PubMed1993

Cloning of a DNA probe and its application in the detection of Plasmodium falciparum. A preliminary report.

The clones containing parasite DNA fragments were screened from a genomic DNA library of Plasmodium falciparum FCC1/HN isolate. A DNA probe derived from clone pBF4 consisting of 3 kilobase pairs hybridizes specifically with P. falciparum DNA but not with human DNA, P. cynomolgi DNA or P. berghei DNA. The nick translated radiolabelled probe can detect 10 pg purified P. falciparum DNA and a 0.001% parasitemia after 24 hours of film exposure. The probe reacts with all microscopically diagnosed P. falciparum samples and 3 of 41 P. vivax samples as well but not with any of 10 human DNA samples.

Adult↗
PubMed1992

Molecular cloning of Plasmodium falciparum blood stage antigens and application of the recombinant proteins in serodiagnosis.

A Plasmodium falciparum genomic DNA library was established in the expression vector lambda gt11, cloned in Escherichia coli. The library was screened with human hyperimmune sera by in situ hybridization. Twenty clones expressing P. falciparum sequences as polypeptides fused to beta-galactosidase were identified. One, CD3A/9025/60, reacted with all immune sera and expressed polypeptides that were larger than beta-galactosidase as well as reacting with antibodies to beta-galactosidase and to P. falciparum. When the fusion proteins were used as target antigens to diagnose malaria antibodies, a result was obtained which correlated well with indirect fluorescence assay.

Animals↗
PubMed1991

[Fusion protein Dot-ELISA for the detection of Plasmodium falciparum antibodies].

The feasibility of using fusion protein Dot-ELISA to detect the antibodies to Plasmodium falciparum was presented. Fusion protein expressed in the P. falciparum genomic DNA expression library with lambda gt11 was used as the antigen to coat the solid support nitrocellulose strips. Horseradish peroxidase conjugated with goat antihuman IgG was used as the second antibody. The enzyme activity was read by naked eyes according to the dot colour. The results by Dot-ELISA correlated well with those by IFA. The study indicated that this method was specific, sensitive, simple, and replicable. It would be valuable for further studying the usefulness of fusion protein in the immunodiagnosis of malaria.

Animals↗
PubMed1990

Primary amine drug selective electrodes with special crown ethers as neutral carriers.

Ionophores selectively sensitive to primary amines have been synthesized which display low potentiometric selectivity coefficients for K+, Na+ and NH4+ ions, secondary and tertiary amines as well as quaternary ammonium ions. These ionophores include macrocyclic polyethers with dinaphthyl subunits and azocrown ether with nitrogen donor atoms. The feasibility of these ionophores for preparing primary amine drug selective electrodes was investigated in detail. Practically usable PVC membrane electrodes sensitive to primary amine drugs, such as mexiletine, dopamine, metaraminol and tryptamine, and aliphatic primary amines have been prepared with these ionophores as neutral carriers. Direct potentiometric methods for assaying these drugs have been proposed by using the prepared electrodes. The proposed primary amine drug selective electrodes are remarkably superior to those based on ion-associates. Compared with the electrodes based on common ethers, the interference by K+, Na+ and NH4+ ions is substantially reduced. A digital simulation of the electrochemical process concerning the membrane transport was performed and some interesting conclusions have been drawn.

Dopamine↗
PubMed1986

Identification of the thymidine kinase gene of infectious bovine rhinotracheitis virus and its function in Escherichia coli hosts.

In an attempt to understand the gene expression of the infectious bovine rhinotracheitis virus (IBRV), the viral thymidine kinase gene (tk), a well regulated viral gene has been chosen for this study. A cosmid library of IBRV has been constructed in Escherichia coli HB101 by cloning partially Sau3A-digested DNA fragments into a cosmid vector, pJB8. Recombinant cosmids were further analyzed by restriction digestions and by Southern blot hybridization. Results showed that this cosmid library comprised all of the IBRV genome with the exception of both termini. The individual recombinant cosmid clones were then used to transform E. coli tdk- mutant strains, Ky895 or C600tdk- for the selection of the IBRV tk gene. The clones able to grow on the selection plates containing 5-fluorouracil, uridine, thymidine and ampicillin were selected and further characterized. The physical location of the viral DNA inserts of one of the clones, pIBR5, was determined and the sequences complementing the tk activity have been isolated by subcloning. The plasmid, pIBRTK, was shown to grow on selection plates and therefore, retained the ability to complement the tk gene. The E. coli mutant strain C600tdk- harboring pIBRTK partially restores the tk activity by exhibiting a three and half fold increase in the level of the incorporation of [3H]thymidine into bacterial DNA over that of C600tdk- mutant.

Chromosome Deletion↗