[The influences of Tet system on activity and tissue specificity of HBV Cp.].

Aim: Analyze the effect of Tetracycline-controlled system on Hepatitis B virus core promoter (Cp) activity and tissue specificity.

Methods: The 7 Teto sequence was amplified from plasmid pTL-8 using polymerase chain reaction (PCR) and cloned into T vector pMD19-T Simple. After sequencing, the 7 teto sequence was subcloned into upstream of Cp in pGL3-Basic/Cp.

[Biosynthesis, catabolism and related signal regulations of plant chlorophyll].

Plant photosynthesis is determined by chlorophyll (Chl) metabolism, which is an important factor of determining crop yield. The genes involved in Chl biosynthesis, catabolism, and related signal regulations are numerous, and the mutation of any of them may change the pigment level, causing abnormalities in leaf color and even inducing individual death. Spontaneous or artificial mutants are necessary for functional analysis of Chl related genes.

[Prediction and modification analysis of low-affinity HLA-A*0201 restricted CTL epitopes derived from HIV-1 pol antigen].

Aim: To screen the possible HLA-A*0201 restricted low-affinity CTL epitopes derived from HIV-1 pol antigen and to predict and identify the possible change of the affinity between epitope and the HLA-A*0201 molecule when the epitope is modified.

Methods: HLA-A*0201 restricted low-affinity CTL epitopes were predicted by CTL epitope prediction software based on super motif, proteasome cleavage probability, HLA affinity and so on. The candidates were modified acid substitution and analyzed by computer.

[Cloning and expression of PbTIP analogous gene from Plasmodium berghei ANKA and preparation of its polyclonal antibody].

Objective: To clone and express a novel protein analogous to TIP (T cell immunomodulatory protein) of Plasmodium berghei ANKA and prepare its polyclonal antibody.

Methods: The PbTIP encoding nucleotide sequence was searched from the Plasmodium berghei genomic database and amplified by PCR. The gene was sub-cloned into prokaryotic expression vector pGEX4T-1 and expressed in E.

[DNA/MVA combined immunization: antibody response to Plasmodium falciparum merozoite surface protein 1 in mice].

Objective: To explore the effect of DNA/MVA combined immunization in enhancing antibody response to MSP1.

Methods: DNA vaccine and recombined MVA were constructed based on synthesized MSP1 gene (3D7). BALB/c mice were primed with DNA solely or together with GM-CSF expressing plasmid and then boosted with rMVA/ 190.

Effect of sodium citrate based anticoagulants on the growth activity of malaria parasites.

Objective: To study the effect of anticoagulants based on sodium citrate on the growth activity of malaria parasites.

Methods: The parasites were treated with 3 anticoagulants (ACD, CD and SC), respectively, and the parasitemia was determined to measure the effect of the anticoagulants on the growth of the parasites. Unsynchronized Plasmodium falciparum was treated with the anticoagulants at different concentrations for 3 h at 37 degrees C.

[Modulation of immune response to Plasmodium falciparum apical membrane antigen 1 DNA vaccine by cytokine plasmids].

Objective: To explore the effect of cytokine encoding plasmids on DNA immunization in mice.

Methods: Prototype DNA vaccine VR1020/E which contain Plasmodium falciparum apical membrane antigen 1 (AMA1) ectodomain was constructed, and eukaryotic expression vectors pcDNA3/GM-CSF, pcDNA3.1(-)/IL-4, pIL-12 and pGM-CSF/pTPA-E were also built.

Effects of tetracycline operator element insertion on Plasmodium falciparum glycophorin binding protein 130 gene promoter activity.

Objective: To construct tetracycline operator (TetO) modified glycophorin binding protein 130 gene (GBP130) promoter of Plasmodium falciparum and investigate the position effect of insertion of TetO on the promoter activity.

Methods: Cloning of 7-copy of TetO (7cot) sequence into 4 points relative to transcriptional initiation site of GBP130 promoter in pGBPCATdelta2 plasmid (2 upstream and 2 downstream), respectively, produced 4 derivative plasmids, pG/7T (-5), pG/7T (-2), pG/7T (+2) and pG/7T (+5). After transient transfection, the expression level of reporter gene CAT in both pGBPCATdelta2 and its derivative plasmids was detected and analysed by CAT ELISA.

[Protective antibody response to recombinant fragments of Plasmodium falciparum apical membrane antigen 1].

Objective: To determine the role of putative apical membrane antigen (AMA)1 domains in inducing protective immunity and to provide basis for selection of vaccine applicable segments.

Methods: Encoding gene segments of AMA1 were amplified and cloned into pET prokaryotic expression vectors. Recombinant proteins were expressed and purified.

Functional characterization of the 5' proximal flanking fragment of Plasmodium falciparum GBP130 gene.

Objective: To identify the putative regulation elements with strength- and stage-specificity in 5' proximal flanking sequence of P. falciparum GBP130 gene.

Methods: Plasmids containing different deletions of upstream of the GBP130 promoter were constructed.