Objective To investigate the expression level of virulence-associated genes in promastigotes and amastigotes of different Leishmania spp.. Methods Total RNA was extracted from the promastigotes and amastigotes of Leishmania donovani, L. infantum, L. tropica, L. major and L. mexicana, and relevant strains. According to the reported gene sequences in GenBank, primers were designed in relation to the virulence-associated genes [GDP-mannose pyrophosphorylase (GDPMP), 3′a2rel-related protein (A2rel), beta-galactofuranosyl transferase (LPG1), lipophosphoglycan biosynthetic protein (LPG2), kinetoplast membrane protein 11 (KMP-11), cpc gene for cysteine proteinase (CPC), hydrophilic acylated surface protein (HASPB1), cathepsin L-like cysteine protease (CPB2), cathepsin L-like cysteine proteinase lmcpb2.8 (CPB2.8), Mr 100 000 heat shock protein (CLP b)], and control genes (alpha tubulin gene and GAPDH). Semi-quantitative RT-PCR was performed to detect expression level of these genes in promastigotes and amastigotes of different Leishmania spp. Results There was a significant difference in the expression profiles of the genes among the promastigotes and amastigotes of different Leishmania spp. The HASPB1 was detected in the amastigotes of all strains and promastigotes of L. donovani, the GDPMP, LPG1, LPG2, CPB2.8, CPB2, CPC, A2rel and CLP b were expressed in the promastigotes and/or amastigotes of the specific Leishmania spp, respectively. None of the stains carried the KMP-11 gene, whereas the amastigotes of L. donovani SC10 strain and L. major 5ASKH strain possessed CPC. Conclusion The expression profile of the virulence-associated genes shows species-specific and stage-specific differences.

Objective] To analyze the sequence difference of the SSU rDNA variable regions of Leishmania isolates from hilly foci and plain foci of China. [Methods] Specific SSU rDNA fragments from nuclear DNA of five Leishmania species and isolates were amplified by PCR. The amplified DNA fragments were cloned into pGEM R\|T Easy vector. The specific fragments were sequenced by the automated DNA sequencer. [Results] Sequence analysis showed that the amplified DNA fragments of five Leishmania species and isolates were all 392 bp in length, point mutations were located in the two unique sequence (UQ\|Ⅰ and UQ\|Ⅱ); L.d.SC10 and L.d.GS7 had two same point mutations in UQ\|Ⅱ, only L.d.GS7 had one in UQ\|Ⅰ; no insertion/deletion. [Conclusion] Sequence difference of the SSU rDNA variable region existed between Leishmania isolates from hilly foci and plain foci; The sequences of the SSU rDNA variable regions of L.d. SD2 isolate and L.infantum were identical.

Objective] By sequencing of SSU rRNA gene cloning from Xinjiang cutaneous leishmaniasis pathogen (XJCLP) to provide evidence for identification of the pathogen. [Methods] By PCR assay with primers R222 and R333, the specific fragment had been produced from SSU rRNA gene of XJCLP , L infantum, L tropica and cloned into pGEM ○[KG-6/7]R T Easy vector .The clones were sequenced by the Sanger dideoxy mediated chain termination method, analysis of SSU rRNA gene sequences from XJCLP, L tropica, L infantum with DNASIS. [Results] Sequence analysis showed that the specific fragment of SSU rRNAgene from XJCLP, L infantum,L tropica , were all 394 bp in length. There were 391 bases identical and three point mutations between the sequences of XJCLP and L tropica , the similarity being 99 2%; 390 bases identical and three point mutations and one insertion /deletion between the sequences of XJCLP and L infantum , the similarity being 99 0%. One insertion/deletion between the sequences of L tropica and L infantum , the similarity being 99 7%. The primary and secondary structures of SSU rRNA gene from XJCLP differed from those of L infantum and L tropica .A retrieval from GenBank confirmed that these 394 bp sequence are new gene sequences. [Conclusion]The primary and secondary structures of SSU rRNA gene from XJCLP, L infantum , L tropica were different. 394 bp sequence from SSU rRNA gene of XJCLP is a new gene sequence.

Objective To explore the protein profile and identify developmentally regulated proteins of the promastigotes and axenic amastigotes with comparative proteomics technique.Methods The total proteins of promas-tigotes and axenic amastigotes of Leishmania donovani SC6 strain were separated by two-dimensional electrophoresis(2-DE) in a broad pH range(3-10) , and the gel was stained with Coomassie blue.The images were analyzed by PDQuest 1.0 software, and the major developmentally regulated proteins were identified by electrospray mass spectrometry.Results Approximately 700 protein spots were revealed in equivalent proteins of the promastigotes and axenic amastigotes separated by 2-DE, among which more than 90% protein spots showed equivalent quantity and distribution, with 6 proteins up-regulated and 3 proteins down-regulated in axenic amastigotes compared with promastigotes.Five of the 6 up-regulated proteins were with known function, respectively ascribed as Reiske iron-sulfur protein precursor, ?-tubulin, peroxidoxin 1, dihydrolipoamide acetyltransferase precursor, and mannose-1-phosphate guanyltransferase.Two of the 3 down-regulated proteins were identified as heat shock protein 70 and ?-tubulin.The functions of the developmentally regulated proteins were related to the carbohydrate/energy metabolism, stress response, or formation of cell membrane/cytoskeleton.Conclusion The findings demonstrate the differences in protein expression profiles between promastigotes and amastigotes.

Objective:To study the relation between conserved motif of sphingosine 1-phosphate receptor type 1(S1P1) and FTY720-induced internalization.Methods:With HA-S1P1(WT)-Myc-EGFP-N1 fusion vector as template,HA-S1P1(R142N)-Myc-EGFP-N1 fusion vector was constructed by overlap PCR.The conserved ERY motif of wild type S1P1 was mutated into ENY.The recombinant vectors were confirmed by sequencing,then they were transfected into HEK293 cells by Polyfect.The transfected HEK293 cells were selected with G418.Cells were incubated for 3,6,12 hours in the absence or presence of 100 nmol/L FTY720,then S1P1 gene expression was analyzed by fluorescence microscopy.Results:Sequencing confirmed HA-S1P1(R142N)-Myc-EGFP-N1 vectors was successfully constructed.S1P1(WT) protein and S1P1(R142N) protein were expressed on the stably transfected-HEK293 cell surface.FTY720 induced S1P1(WT) internalization,but not S1P1(R142N).Conclusion:FTY720-induced S1P1 internalization is related with conserved ERY motif.

OBJECTIVETo confirm the existence of point mutations in the SSU rDNA variable regions of 5 Leishmania donovani (L.d.) isolates from different epidemic foci in China.

METHODSSpecific SSU rDNA fragments from nuclear DNA of 7 Leishmania species/isolates were amplified by PCR and then cloned into pGEM(R)-T Easy Vectors. After that, the specific fragments were sequenced by an automated DNA sequencer.

RESULTSSequence analysis showed that the amplified DNA fragments of 7 Leishmania species/isolates were all 392 bp in length. All 5 point mutations were located in two unique sequence blocks (UQ-I and UQ-II), and no insertions or deletions were found. The identities of comparison of Leishmania in GeneBank were more than 98%.

CONCLUSIONFive point mutations exist in the SSU rDNA variable region of 5 L.d. isolates from different epidemic foci of visceral leishmaniasis (VL) in China. Sequence differences of the SSU rDNA variable region exist among L.d. isolates from different foci.

Animals ; DNA, Protozoan ; chemistry ; DNA, Ribosomal ; chemistry ; Humans ; Leishmania donovani ; genetics ; Leishmaniasis, Visceral ; parasitology ; Point Mutation ; Polymerase Chain Reaction