Level of CYP4G19 Expression Is Associated with Pyrethroid Resistance in Blattella germanica.

German cockroaches have become a large problem in the Shenzhen area because of their pesticide resistance, especially to pyrethroid. A pyrethroid called "Jia Chong Qing" to prevent pests for a long time were found to be resistant to "Jia Chong Qing" with resistance index of 3.88 measured using RT-PCR and immunohistochemistry analysis showed that both CYP4G19 mRNA and CYP4G19 protein expression levels in the wild strain were substantially higher than that of a sensitive strain. dsRNA segments derived from the target gene CYP4G19 were prepared using in vitro transcription and were microinjected into abdomens of the wild strain. Two to eight days after injection, the result showed that CYP4G19 mRNA expressions were significantly reduced in the groups injected with dsRNAs.

[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. T2 cells were used to determine the peptide by amino binding affinity and HLA-A*0201-peptide complex stability. RESULTS: Among the three predicted peptides by softer ware, YVSLSFPQI (pol52-60Y1), YVSQIIEQL pol(673-681Y1), YIQKETWEA(pol548-556Y1)could bind to HLA-A*0201 with high affinity, and the dissociation time of 50% HLA-A*0201 peptide complex was over to 8 h. CONCLUSION: Our results suggest that the three predicted peptides, as modification, might be HLA-A*0201 restricted CTL epitopes.

Characterization of the genome sequence of an oncolytic Newcastle disease virus strain Italien.

We determined the complete genome sequence of strain Italien, a virulent and oncolytic strain of Newcastle disease virus (NDV) by direct nucleotide sequencing of RT-PCR products, a size of 15,186 nucleotides (nt). Comparison of six coding genes and non-coding regions of Italien with those of the other 25 sequenced strains revealed NDV Herts/33 was the most similar strain with Italien. The gene encoding the RNA dependent RNA polymerase was the most highly conserved, while the gene encoding phosphoprotein was the most highly variable. The HN and F proteins of Italien have been modeled on the crystal structure in order to study the structural characteristics. Interaction between the HN protein and the heptad repeat B (HRB) region of F protein was analyzed in silico by molecular docking predicted five critical residues I133, V142, D143, R480, and K567 on HN protein. Identification of amino acid residues that could be crucial for this interaction provides working hypotheses for subsequent studies.

[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.coli BL21 (DE3). After induction by IPTG, the expression of PbTIP-GST fusion protein was characterized by SDS-PAGE and Western blotting. The inclusion bodies of GST-PbTIP fusion protein were injected into BALB/c mouse. Anti-sera were identified by indirect fluorescent antibody test and western blotting. RESULTS: The PbTIP-GST fusion protein was successfully expressed in the form of inclusion bodies, by controlling the temperature and concentration of IPTG. Anti-PbTIP-GST sera were acquired with high titer. The sera specifically recognized the PbTIP with a band of 60 000 in P.berghei infected erythrocyte protein. CONCLUSION: PbTIP/GST fusion protein and polyclonal antibody have been obtained.

Targeted inhibition of HBV gene expression by single-chain antibody mediated small interfering RNA delivery.

UNLABELLED: RNA interference is highly effective at inhibiting HBV gene expression and replication. However, before small interfering RNA (siRNA) can be used in the clinic, it is essential to develop a system to target their delivery. Antibody-mediated delivery is a novel approach for targeting siRNA to appropriate cells. In this report, we asked whether this siRNA delivery strategy would be effective against HBV. Of 5 candidates, a specific siRNA that effectively inhibited HBV gene expression and replication was determined. Two fusion proteins, s-tP and sCkappa-tP, were constructed to contain a single chain of the human variable fragment, scFv, against hepatitis B surface antigen (HBsAg), a truncated protamine (tP), and in the case of sCkappa-tP, a constant region of the kappa chain (Ckappa). S-tP and sCkappa-tP were developed to provide targeted delivery of the siRNA, siRNA expressing cassettes (SEC), and siRNA-producing plasmids. Fluorescein isothiocyanate-siRNA, fluorescein isothiocyanate-SEC, and plasmid DNA were specifically delivered into HBsAg-positive cells using the sCkappa-tP fusion protein, and effectively inhibited HBV gene expression and replication. HBV gene expression was also inhibited by siRNA or siRNA-producing plasmids in HBV transgenic mice. CONCLUSION: Our results describe a potential method for the targeted delivery of siRNA or siRNA-producing plasmids against HBV, using anti-HBsAg fusion proteins.

[Adenovirus-mediated delivery of targeted ribonuclease against HBV replication in vitro].

OBJECTIVE: To observe the inhibitory effect of targeted ribonuclease delivered via adenovirus against HBV replication in vitro. METHODS: The shuttle plasmids pDC316 were constructed on the basis of the previous plasmids pcDNA3.1(-)/TRL, pcDNA3.1(-)/TR, pcDNA3.1(-)/TRmut, pcDNA3.1(-)/HBVc, and pcDNA3.1(-)/hEDN by subcloning the target gene sequences of TRL, TR, HBVc, and hEDN, respectively. HEK 293 cells were cotransfected with the pDC316 plasmids respectively in the presence of the rescue plasmid pBHGlox(delta)E1,3Cre to yield the recombinant adenoviral vectors which comprised the above genes. After transfection of HepG2.2.15 cells with the vectors, RAd/TRL expression was detected by indirect immunofluorescence staining and RT-PCR. Radioimmunoassay was used to analyse anti-HBV activity of RAd/TRL. RESULTS: Recombinant RAd vectors were prepared successfully. Effective expression of RAd/TRL in HepG2.2.15 cells resulted in a significant decrease of HBsAg and HBeAg concentration in comparison with the controls. CONCLUSION: Adenoviral vector-mediated targeted ribonuclease can effectively inhibit HBV replication.

[Expression, purification and transduction of Tat-p53 fusion protein].

AIM: To express and purify Tat-p53 fusion protein and investigate its transduction efficiency. METHODS: The gene encoding wide-type p53 was isolated using RT-PCR from A549 cell line and cloned into pTAT-HA and pET32a prokaryotic expression vectors. Recombinant plasmids were transformed into E.coli BL21(DE3)LysS, then the transformed cells were induced with IPTG. The expression and purification of the Tat-p53 and p53 were analyzed by SDS-PAGE. BALB/c mice were immunized with purified p53 protein. The serum was isolated and the antibody specific to p53 was measured by ELISA. The transduction efficiency of Tat-p53 was detected using indirect immunofluorescence assay. RESULTS: Prokaryotic expression vectors of Tat-p53 and p53 were constructed correctly. Tat-p53 fusion protein and p53 protein were successfully expressed and purified. p53 specific mouse antiserum was obtained. IFA result indicated that Tat-p53 fusion protein transduced into HepG2 cells efficiently. CONCLUSION: The obtained Tat-p53 fusion protein may be valuable for the basic research on therapy for liver carcinoma.

[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. Serum IgG and subtype IgG1 and IgG2a were assayed by ELISA. All mice were challenged with allelic replaced Plasmodium berghei. RESULTS: Antibodies to MSP1-190 were detected after DNA immunization with an end-point dilution titer of 1:2500. When GM-CSF plasmid was added, the antibody end-point dilution titer reached 1:11150, with an increase of 53 and 10 times respectively after MVA boosting. Among them anti-19000 antibodies were prominent, 1/4-1/3 of total IgG in serum. However, when the mice were challenged with Pb-PfM19 no prolonged survival was observed (P>0.05). CONCLUSION: High titer antibodies can be elicited in mice by using codon optimized MSPI gene and DNA/MVA combined immunization. The specificity and protection of these antibodies is being further investigated.

Effect of vector-expressed shRNAs on hTERT expression.

AIM: To study the effect of short hairpin RNAs (shRNAs) expressed from DNA vector on hTERT expression. METHODS: Oligonucleotides coding for four shRNAs against hTERT were cloned into a mammalian shRNA expression vector pUC18U6 to form pUC18U6ht1-4, which were then introduced into HepG2 cells by using liposome-mediated transfection. HepG2 cells transfected by pUC18U6 and pUC18U6GFPsir, which expressed shRNA against green fluorescent protein (GFP), were used as controls. hTERT mRNA in the transfected cells were quantified by using real-time fluorescent RT-PCR. RESULTS: Among the four shRNAs against hTERT, two decreased the hTERT mRNA level. Compared with the controls, pUC18U6ht which expressed the two shRNAs reduced hTERT mRNA by 39% and 49% (P<0.05). CONCLUSION: hTERT expression is inhibited by the shRNAs expressed from the DNA vector.

Anti-HBV activity of TRL mediated by recombinant adenovirus.

AIM: To investigate the inhibitive effect of hepatitis B virus (HBV)-TRL on HBV replication. METHODS: Based on previously constructed pcDNA3.1(-)/TRL, TR, TRmut, HBV core protein (HBVc) and hEDN, interest gene sequences TRL, TR, HBVc and hEDN were inserted into adenovirus shuttle plasmid pDC316 respectively and co-transfected HEK293 cells with rescue plasmid pBHGloxdeltaE1,3Cre to acquire RAd/TRL, TR, HBVc and hEDN. And then RAds were identified, amplified and the titers in HEK293 cells were determined. RAd/TRL and TR were named as the experimental groups, and others were control ones. After HepG2.2.15 cells were infected, RAd/TRL expression was identified by indirect immunofluorescence staining. Supernatant HBV-DNA content was determined by fluorescent quantification PCR. Meanwhile, metabolism of HepG2.2.15 cells was evaluated by MTT colorimetry. RESULTS: RAd vectors with distinct interest gene sequence were successfully constructed. Effective expression of RAd/TRL in HepG2.2.15 cells resulted in a significant decrease of supernatant HBV-DNA content compared to RAd/TR (0.63+/-0.14 vs 1.60+/-0.47, P = 0.0266, <0.05) and other control groups (0.63+/-0.14 vs 8.50+/-2.78, 8.25+/-2.26, 8.25+/-2.29, 8.50+/-1.51, 8.57+/-1.63, P<0.01). MTT assay suggested that there were no significant differences in cell metabolic activity between groups (P>0.05). CONCLUSION: The construction and expression of RAd/TRL has been achieved and it could inhibit HBV replication successfully, which has laid the foundation for further research on anti-HBV activity in vivo.

[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. BALB/c mice were immunized with VR1020/E alone or with VR1020/E plus different cytokine plasmids. Serum IgG and its subtype were determined by ELISA and in vitro splenocyte proliferation assay was done. RESULTS: GM-CSF, IL-4 and IL-12 encoding plasmids all promoted mice immune response to VR1020/E, the antibody level increased 7 to 10 times and splenocyte proliferation was enhanced too. Plasmid pcDNA3/GM-CSF induced much more IgG1 whereas plasmid pIL-12 induced much more IgG2a. CONCLUSION: Cytokine encoding plasmids might be used as adjuvant in AMA1 DNA immunization.

[Quantitation of human telomerase reverse transcriptase mRNA with real-time fluorescent RT-PCR].

AIM: To establish a real-time fluorescent RT-PCR assay to quantify human telomerase reverse transcriptase (hTERT) mRNA. METHODS: Total cellular RNA was isolated from HepG2 cells using Trizol reagent, which was then reverse-transcribed into cDNA. By using a pair of gene-specific primers and a TaqMan MGB probe, cDNA of hTERT was quantified with real-time fluorescent PCR. Human beta-actin (hBA) mRNA was quantified at the same time as an endogenous control. Serial dilutions of cloned human beta-actin gene were used to construct a standard curve. RESULTS: The correlation coefficient of the standard curve was 1.00. The mean coefficient of variation of the assay was 7.1%. The ratio of hTERT mRNA to hBA mRNA of HepG2 cells was (1.3+/-0.3)x10(-4). CONCLUSION: A real-time fluorescent RT-PCR assay to quantify hTERT mRNA was established, which will facilitate the study on the biological function of telomerase.

Quantifying anti-HBV effect of targeted ribonuclease by real-time fluorescent PCR.

AIM: To quantify the inhibition of HBV replication by targeted ribonuclease by using real-time fluorescent PCR. METHODS: Targeted ribonuclease was introduced into 2.2.15 cells by liposome-mediated transfection or HIV-TAT mediated protein transduction. Forty-eight hours after the transfection and 24 h after the transduction, supernatants of 2.2.15 cells were collected and HBV DNA in the supernatants was quantified by real-time fluorescent PCR with a commercial kit. RESULTS: HBV DNA concentrations in the supernatants of 2.2.15 cells transfected or transducted with targeted ribonuclease were 4.9+/-2.4 x 10(8) copies/L and 8.3+/-4.0 x 10(8) copies/L, respectively. Compared with controls, transfection or transduction of targeted ribonuclease reduced HBV DNA concentration in the supernatants of 2.2.15 cells by 90.4% and 90.1%, respectively (P<0.05). CONCLUSION: Targeted ribonuclease can inhibit HBV replication in 2.2.15 cells.

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. RESULTS: Identification by enzyme restrictions and PCR amplifications, as well as DNA sequencing confirmed that the plasmids were successfully constructed. Transfection of these plasmids and CAT detection suggested that insertion of 7cot into each point of GBP130 promoter enhanced the promoter activity, and downstream location of 7cot in the promoter showed higher promoter activity than those located upstream, with the strongest effect in Ins 4 (point +5). CONCLUSION: Plasmid pG/7T (+5), in which 7cot was inserted into +5 point of GBP130 promoter, can be chosen as the responsive plasmid in establishing tetracycline-controlled transgenic expression system of malarial parasites.

[Preliminary study on regulable DNA vaccines against Plasmodium falciparum].

AIM: To construct regulable DNA vaccine against Plasmodium falciparum by using tetracycline(Tet) regulable system. METHODS: Eukaryotic expression vectors pTL-8/apical membrane antigen 1 (AMA-1) (tTA) and pTL-8/AMA-1(rtTA) gene which express trans-activator (tTA) or reverse trans-activator(rtTA), respectively, and AMA-1 gene of Plasmodium falciparum were constructed. BALB/c mice were immunized with these plasmids and doxycycline (dox) was administered to regulate the expression of AMA-1. For some mice immunized with pTL-8/AMA-1(rtTA), pUHS6-1, a plasmid containing trans-silencer (tTS) to suppress basal expression of AMA-1 from pTL-8/AMA-1(rtTA), was injected into these mice together with pTL-8/AMA-1(rtTA). The sera of the mice were isolated at 2,4,6 and 8 weeks post-immunization and the antibodies specific to AMA-1 were measured by ELISA. RESULTS: pTL-8/AMA-1 and pTL-8/AMA-1(rtTA) were constructed successfully. The mice immunized by pTL-8/AMA-1(tTA) with dox or by pTL-8/AMA-1(rtTA) without dox (at these conditions, AMA-1 was expressed at basal level)developed significant antibodies against AMA-1. Mice immunized by pTL-8/AMA-1(rtTA) and pUHS6-1 without dox did not develop significantly antibodies against AMA-1. In contrast, the mice immunized by pTL-8/AMA-1(rtTA) and pUHS6-1 with dox produced high level of antibodies. CONCLUSION: pTL-8/AMA-1(rtTA) combined with pUHS6-1 is a good regulable DNA vaccine candidate against Plasmodium falciparum.

Effect of vector-expressed siRNA on HBV replication in hepatoblastoma cells.

AIM: To study the effect of siRNA expressed from DNA vector on HBV replication. METHODS: Human U6 promoter was amplified from genomic DNA and cloned into plasmid pUC18 to construct a mammalian siRNA expression vector pUC18U6. Then oligonucleotides coding for a short hairpin RNA against HBV were cloned into pUC18U6 to form pUC18U6HBVsir which was introduced into 2.2.15 cells by using liposome-mediated transfection. 2.2.15 cells transfected by pUC18U6 and pUC18U6GFPsir which expressed siRNA against green fluorescent protein and mock-transfected 2.2.15 cells were used as controls. Concentration of HBsAg in the supernatant of the transfected cells was measured by using solid-phase radioimmunoassay. RESULTS: A mammalian siRNA expression vector pUC18U6 was constructed successfully. Compared with controls, pUC18U6HBVsir which expressed siRNA against HBV decreased concentration of HBsAg significantly by 44%(P<0.05). CONCLUSION: HBV replication in 2.2.15 cells is inhibited by siRNA expressed from the DNA vector.

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. Treated erythrocytes were mixed with normal parasites or treated parasites with normal erythrocytes, which was followed by parasitemia determination of the two cultures to determine the cell target of the anticoagulants. Stage-synchronized parasites (ring, trophozoite and schizont) were treated as above to investigate the stage target. P. berghei was also treated with anticoagulants and inoculated in mice to detect the effect of anticoagulants on the animal malaria parasite by counting the parasitemia. RESULTS: All 3 anticoagulants inhibited falciparum parasite growth and ACD had the strongest potency. The treatments of the erythrocyte and the parasite with anticoagulants respectively showed that the anticoagulants targeted the parasites rather than normal erythrocytes. Stage-synchronized parasite treatment suggested anticoagulants primarily inhibited schizonts. The effect of anticoagulants on P. berghei was similar to that on P. falciparum. CONCLUSION: ACD showed the most significant inhibitive effect on the growth of malaria parasites and SC was the best anticoagulant based on sodium citrate for malarial experiments.

[Passage adaptability of candidate strains for hemorrhagic fever with renal syndrome purified vaccine in Vero cells and their immunogenicity].

OBJECTIVE: To adapt the candidate strains of hemorrhagic fever with renal syndrome (HFRS) purified vaccine to Vero cells and to study their antigenicity and immunogenicity. METHODS: The viral strains H8207 (Hantaan virus, HTN) and Y86013 (Seoul virus, SEO) were continuously propagated in Vero cell by the terminal dilution method and studied the characteristics of virus multiplication, viral titers and the amounts of virus antigen after serial passages. Three batches of crude monovalent inactivated vaccine were developed using the different passages of these 2 viral strains. RESULTS: The strains H8207 and Y86013 adapted to Vero cells and stably grew on the cells with high titers. Rabbits immunized with the crude vaccines of H8207 and Y86013 showed 100% sero-conversion and the neutralizing antibody titers of the rabbit immune sera reached 1?10 at 4 weeks after 2 times of immunization. CONCLUSIONS: The results suggest that these 2 candidate strains had adapted to Vero cells, possessed high titers and good immunogenicity and be feasible to prepare the HFRS purified vaccine in Vero cells.