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1.
Comparison of the Leishmania infantum genome with Leishmania braziliensis and Leishmania major genomes has identified 25 L. infantum species‐specific genes that are absent or pseudogenes in L. major and L. braziliensis. To determine whether these L. infantum species‐specific genes are involved in visceral Leishmania infection, we cloned the orthologues of 14 L. infantum species‐specific genes from the genetically closely related Leishmania donovani and introduced them into L. major. Two of these L. donovani species‐specific genes were found to significantly increase L. major survival in visceral organs in BALB/c mice. One (orthologue of LinJ28_V3.0340; Ld2834) of these two genes was further investigated. The L. donovani Ld2834 null mutants displayed dramatically reduced virulence in BALB/c mice and were unable to survive in axenic amastigote culture conditions arguing that Ld2834 plays a crucial role in enabling L. donovani survive at the increased temperature typically associated with visceral organs. Ld2834 encodes a 50 kDa protein that is localized in the cytoplasma and has no significant sequence similarity with other known genes. This study validates the importance of comparative genomics for understanding Leishmania species pathology and argues that Leishmania species‐specific genes play important roles in tissue tropism and virulence. 相似文献
2.
《Microbes and infection / Institut Pasteur》2014,16(1):61-66
Using fluorescence in situ hybridization, we determined the ploidy of four species of Leishmania: Leishmania infantum, Leishmania donovani, Leishmania tropica and Leishmania amazonensis. We found that each cell in a strain possesses a combination of mono-, di- and trisomies for all chromosomes; ploidy patterns were different among all strains/species. These results extend those we previously described in Leishmania major, demonstrating that mosaic aneuploidy is a genetic feature widespread to the Leishmania genus. In addition to the genetic consequences induced by this mosaicism, the apparent absence of alternation between haploid/diploid stages questions the modality of genetic exchange in Leishmania sp. 相似文献
3.
J. Martin Sanchez F. Morillas Marquez C. Acedo Sanchez M. C. Sanchiz Marin 《Systematic parasitology》1995,30(3):233-238
This study presents the results of characterising 17 strains of Leishmania by isoenzyme electrophoresis from a focus in north-east Almería, south-east Spain. Nine of these were isolated from Phlebotomus pernicious and eight were of canine visceral origin. All the latter were identified as the Leishmania infantum zymodeme GR-1. The homogeneity of these strains greatly contrasts with the heterogeneity observed with those of sandfly origin
for which eight zymodemes are described (GR-2, GR-6, GR-8, GR-10, GR-11, GR-12, GR-13 and GR-14). 相似文献
4.
J. Martin Sanchez F. Ruiz Martinez J. M. Salinas Martinez de Lecea C. Sanchez Rabasco C. Acedo Sanchez M. C. Sanchiz Marin V. Delgado Florencio F. Morillas Marquez 《Systematic parasitology》1996,33(3):177-182
This study presents the results of the characterisation of 17 strains ofLeishmania by isoenzyme electrophoresis from a focus of leishmaniasis in southern Spain: two from human visceral leishmaniasis, four from human cutaneous leishmaniasis and 11 from sandflies. The 17 strains are grouped in 6 zymodemes characterised by their variability as regards to the electrophoretic mobility of the enzymes MDH, G6PD, NP and ME. Thus, we confirm the high intraspecific variability ofLeishmania (L.) infantum in a focus of southern Spain, as already suggested by previous studies. Zymodemes GR-15 and GR-17 are also described for the first time in Spain, and they characteristically possess the same relative electrophoretic mobility in the enzyme ME (93). Sixteen zymodemes of theL. infantum complex found in southern Spain were numerically analysed on the basis of the enzymatic profiles of 122Leishmania strains characterised from this area. 相似文献
5.
Gene expression modulation is associated with gene amplification, supernumerary chromosomes and chromosome loss in antimony-resistant Leishmania infantum
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Philippe Leprohon Danielle Lgar Frdric Raymond ric Madore Gary Hardiman Jacques Corbeil Marc Ouellette 《Nucleic acids research》2009,37(5):1387-1399
Antimonials remain the first line drug against the protozoan parasite Leishmania but their efficacy is threatened by resistance. We carried out a RNA expression profiling analysis comparing an antimony-sensitive and -resistant (Sb2000.1) strain of Leishmania infantum using whole-genome 70-mer oligonucleotide microarrays. Several genes were differentially expressed between the two strains, several of which were found to be physically linked in the genome. MRPA, an ATP-binding cassette (ABC) gene known to be involved in antimony resistance, was overexpressed in the antimony-resistant mutant along with three other tandemly linked genes on chromosome 23. This four gene locus was flanked by 1.4 kb repeated sequences from which an extrachromosomal circular amplicon was generated in the resistant cells. Interestingly, gene expression modulation of entire chromosomes occurred in the antimony-resistant mutant. Southern blots analyses and comparative genomic hybridizations revealed that this was either due to the presence of supernumerary chromosomes or to the loss of one chromosome. Leishmania parasites with haploid chromosomes were viable. Changes in copy number for some of these chromosomes were confirmed in another antimony-resistant strain. Selection of a partial revertant line correlated antimomy resistance levels and the copy number of aneuploid chromosomes, suggesting a putative link between aneuploidy and drug resistance in Leishmania. 相似文献
6.
Leishmania infantum causes visceral leishmaniasis in all countries in the Mediterranean basin. It uses Phlebotomine sandflies as vectors where the promastigote stage develops, reproduces and becomes infective. Therefore the reproductive power of the promastigotes determines the inoculum size of the isolate. Ten Leishmania strains from Cyprus: two Leishmania donovani and eight L. infantum were used to study the proliferation capacity of the promastigotes. Population increase during a 6-day culture period was assessed quantitatively, by haematocytometer enumeration, and qualitatively by following the division history of each population during the same period by CFSE staining and flow cytometry. The strains exhibited different proliferation rates with L. infantum showing higher multiplication rates than L. donovani. These differences may represent their fitness capabilities and their ability to synchronize the multiplication activity of individual members in the population for the production of a sizeable inoculum in time for the vector’s blood meal. 相似文献
7.
《Gene》1997,194(1):77-80
A simple method for the chromosomal assignment of any DNA marker would be an important tool for the ongoing project to map the genome of the protozoan parasite Leishmania. The Leishmania chromosomes enter pulsed field gel electrophoresis (PFGE) gels under current electrophoretic conditions, but their direct identification in a given strain is hampered by their stacking in a few chromosomal bands, and by the very frequent size variations of the same chromosome among parasite strains. To overcome these problems, we determined the complete karyotypes of 12 Old World Leishmania cloned strains. This enabled us to select three of these strains that display great chromosome size polymorphisms, such that every chromosome can be individualized by a specific pattern after hybridization onto these three karyotypes. The complete resolution of the genomes of these three strains can be carried out with only three electrophoretic conditions. This makes a series of three blots sufficient for the assignment of any new marker on a particular Leishmania chromosome. 相似文献
8.
9.
The dog is the main reservoir of Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in humans in Southern Europe. In order to identify the risk of dogs from
a Leishmania non-endemic area traveling to a Leishmania -endemic area becoming infected and the risk of transmitting infection to humans in non-endemic areas an investigation was
performed, in which the results of a questionnaire were combined with the results of a serologic survey. 相似文献
10.
Matthew B. Rogers Tim Downing Barbara A. Smith Hideo Imamura Mandy Sanders Milena Svobodova Petr Volf Matthew Berriman James A. Cotton Deborah F. Smith 《PLoS genetics》2014,10(1)
Although asexual reproduction via clonal propagation has been proposed as the principal reproductive mechanism across parasitic protozoa of the Leishmania genus, sexual recombination has long been suspected, based on hybrid marker profiles detected in field isolates from different geographical locations. The recent experimental demonstration of a sexual cycle in Leishmania within sand flies has confirmed the occurrence of hybridisation, but knowledge of the parasite life cycle in the wild still remains limited. Here, we use whole genome sequencing to investigate the frequency of sexual reproduction in Leishmania, by sequencing the genomes of 11 Leishmania infantum isolates from sand flies and 1 patient isolate in a focus of cutaneous leishmaniasis in the Çukurova province of southeast Turkey. This is the first genome-wide examination of a vector-isolated population of Leishmania parasites. A genome-wide pattern of patchy heterozygosity and SNP density was observed both within individual strains and across the whole group. Comparisons with other Leishmania donovani complex genome sequences suggest that these isolates are derived from a single cross of two diverse strains with subsequent recombination within the population. This interpretation is supported by a statistical model of the genomic variability for each strain compared to the L. infantum reference genome strain as well as genome-wide scans for recombination within the population. Further analysis of these heterozygous blocks indicates that the two parents were phylogenetically distinct. Patterns of linkage disequilibrium indicate that this population reproduced primarily clonally following the original hybridisation event, but that some recombination also occurred. This observation allowed us to estimate the relative rates of sexual and asexual reproduction within this population, to our knowledge the first quantitative estimate of these events during the Leishmania life cycle. 相似文献
11.
PCR has proved useful for rapid diagnosis and typing of Leishmania. Lack of specificity to discriminate between species and/or sensitivity to detect from clinical samples has always been an issue. Previously developed primers either require PCR–RFLP analysis for Leishmania aethiopica discrimination or lack sensitivity to detect L. aethiopica from clinical samples. Here we report the development and validation of L. aethiopica specific PCR primers (V5F/V10R) based on cysteine protease B (cpb), a multicopy and polymorphic gene of Leishmania. V5F/V10R primers differentiate L. aethiopica from Leishmania tropica, Leishmania major, Leishmania donovani and Leishmania infantum by direct PCR. In addition, they are sensitive enough to detect L. aethiopica from biopsy samples. The primers can be very useful for epidemiological studies, species typing and diagnosis of L. aethiopica directly from clinical samples. Implementation of these primers in routine L. aethiopica diagnosis can improve detection rate, save time, money and labor required for culturing Leishmania. 相似文献
12.
Shahram Khademvatan Neda Adibpour Alborz Eskandari Saeed Rezaee Mahmoud Hashemitabar Fakher Rahim 《Experimental parasitology》2013
This in silico and in vitro comparative study was designed to evaluate the effectiveness of some biurets (K1 to K8) and glucantime against Leishmania major and Leishmania infantum promastigotes. Overall, eight experimental ligands and glucantime were docked using AutoDock 4.3 program into the active sites of Leishmania major and Leishmania infantum pteridine reductase 1, which were modeled using homology modeling programs. The colorimetric MTT assay was used to find L. major and L. infantum promastigotes viability at different concentrations of biuret derivatives in a concentration and time-dependent manner and the obtained results were expressed as 50% and 90% of inhibitory concentration (IC50 and IC90). In silico method showed that out of eight experimental ligands, four compounds were more active on pteridine reductase 1. K3 was the most active against L. major promastigotes with an IC50 of 6.8 μM and an IC90 of 40.2 μM, whereas for L. infantum promastigotes was K8 with IC50 of 7.8 μM. The phenylethyl derivative (K7) showed less toxicity (IC50s > 60 μM) in both Leishmania strains. Glucantime displayed less growth inhibition in concentration of about 20 μM. In silico and especially docking results in a recent study were in accordance with the in vitro activity of these compounds in presented study and compound K3, K2 and K8 showed reasonable levels of selectivity for the Leishmania pteridine reductase 1. 相似文献
13.
Telomeres are DNA-protein complexes that protect linear chromosomes from degradation and fusions. Telomeric DNA is repetitive and G-rich, and protrudes towards the end of the chromosomes as 3'G-overhangs. In Leishmania spp., sequences adjacent to telomeres comprise the Leishmania conserved telomere associated sequences (LCTAS) that are around 100 bp long and contain two conserved sequence elements (CSB1 and CSB2), in addition to non-conserved sequences. The aim of this work was to study the genomic organization of Leishmania (Leishmania) amazonensis telomeric/subtelomeric sequences. Leishmania amazonensis chromosomes were separated in a single Pulsed Field Gel Electrophoresis (PFGE) gel as 25 ethidium bromide-stained bands. All of the bands hybridized with the telomeric probe (5'-TTAGGG-3')3 and with probes generated from the conserved subtelomeric elements (CSB1, CSB2). Terminal restriction fragments (TRF) of L. amazonensis chromosomes were analyzed by hybridizing restriction digested genomic DNA and chromosomal DNA separated in 2D-PFGE with the telomeric probe. The L. amazonensis TRF was estimated to be approximately 3.3 kb long and the telomeres were polymorphic and ranged in size from 0.2 to 1.0 kb. Afa I restriction sites within the conserved CSB1 elements released the telomeres from the rest of the chromosome. Bal 31-sensitive analysis confirmed the presence of terminal Afa I restriction sites and served to differentiate telomeric fragments from interstitial internal sequences. The size of the L. amazonensis 3' G-overhang was estimated by non-denaturing Southern blotting to be approximately 12 nt long. Using similar approaches, the subtelomeric domains CSB1 and CSB2 were found to be present in a low copy number compared to telomeres and were organized in blocks of 0.3-1.5 kb flanked by Hinf I and Hae III restriction sites. A model for the organization of L. amazonensis chromosomal ends is provided. 相似文献
14.
15.
M. Pombi A. Giacomi G. Barlozzari J. Mendoza-Roldan G. Macrì D. Otranto S. Gabrielli 《Medical and veterinary entomology》2020,34(4):470-475
The detection of atypical Kinetoplastida in vertebrate hosts and vectors might suggest unexpected host-parasite contacts. Aside to major vectors of Leishmania (Leishmania) infantum in Italy (e.g. Phlebotomus perniciosus and Phlebotomus perfiliewi), the sand fly fauna also includes Sergentomyia minuta, herpetophilic and proven vector of Leishmania (Sauroleishmania) tarentolae, in which records of blood meal on mammals and detection of L. infantum DNA are increasing. This study was conducted in Central Italy aiming to molecularly detect potential atypical Leishmania host-vector contacts. Detection of Leishmania spp. DNA was performed by polymerase chain reaction (SSU rRNA, ITS1 targets) on field-collected sand fly females (N = 344), blood samples from humans (N = 185) and dogs (N = 125). Blood meal identification was also performed on engorged sand flies. Leishmania spp. DNA was found in 13.1% sand flies, 3.7% humans and 14.4% dogs. Sequence analysis identified L. infantum in S. minuta (4.4%), P. perniciosus (9.1%), humans (2.2%) and dogs (14.4%). Leishmania tarentolae was detected in S. minuta (12.6%), P. perfiliewi (6.6%) and human (1.6%) samples. Of 28 S. minuta examined for blood meal, 3.6 and 21.4% scored positive for human and lizard DNA, respectively. These results indicate the importance of one-health approach to explore new potential routes of transmission of leishmaniasis involving S. minuta. 相似文献
16.
Bolhassani A Taheri T Taslimi Y Zamanilui S Zahedifard F Seyed N Torkashvand F Vaziri B Rafati S 《Experimental parasitology》2011,(3):637-645
Reporter genes have proved to be an excellent tool for studying disease progression. Recently, the green fluorescent protein (GFP) ability to quantitatively monitor gene expression has been demonstrated in different organisms. This report describes the use of Leishmania tarentolae (L. tarentolae) expression system (LEXSY) for high and stable levels of GFP production in different Leishmania species including L. tarentolae, L. major and L. infantum. The DNA expression cassette (pLEXSY-EGFP) was integrated into the chromosomal ssu locus of Leishmania strains through homologous recombination. Fluorescent microscopic image showed that GFP transgenes can be abundantly and stably expressed in promastigote and amastigote stages of parasites. Furthermore, flow cytometry analysis indicated a clear quantitative distinction between wild type and transgenic Leishmania strains at both promastigote and amastigote forms. Our data showed that the footpad lesions with GFP-transfected L. major are progressive over time by using fluorescence small-animal imaging system. Consequently, the utilization of stable GFP-transfected Leishmania species will be appropriate for in vitro and in vivo screening of anti-leishmanial drugs and vaccine development as well as understanding the biology of the host–parasite interactions at the cellular level. 相似文献
17.
18.
Molecular screening of Leishmania spp. infection and bloodmeals in sandflies from a leishmaniasis focus in southwestern Turkey
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M. KARAKU Ş M. PEKAĞ IRBA Ş S. DEMIR H. EREN S. TÖZ Y. ÖZBEL 《Medical and veterinary entomology》2017,31(2):224-229
Leishmaniasis is an arthropod‐borne disease that affects approximately 2 million people worldwide annually. The aims of this study were to detect the presence of Leishmania (Kinetoplastida: Trypanosomatidae) DNA and the feeding preferences of probable vector species in an endemic focus of Leishmania infantum in Turkey. Entomological sampling was performed in August and October 2015 in Ayd?n province, where cases of human and canine leishmaniasis have been reported previously. A total of 1059 sandfly specimens comprising nine species belonging to two genera, Phlebotomus and Sergentomyia (both: Diptera: Psychodidae), and five subgenera of the Phlebotomus genus (Phlebotomus, Paraphlebotomus, Larroussius, Adlerius and Transphlebotomus) were collected in five villages. Among all Phlebotomus specimens, Phlebotomus neglectus (39%) was noted as the most abundant species, followed by Phlebotomus tobbi (18%). Leishmania DNA was detected in pools from P. neglectus, P. tobbi and Sergentomyia dentata by kDNA polymerase chain reaction (PCR). Leishmania DNA from Phlebotomus specimens was identified as L. infantum, but Leishmania DNA from Sergentomyia spp. could not be identified to species level by ITS‐1 real‐time PCR. The detection of Leishmania DNA in wild‐caught P. neglectus and the high percentage (24.2%) of human DNA in engorged specimens suggests that P. neglectus is probably an important vector species for L. infantum in Ayd?n province. 相似文献
19.
Hiroshi Uehara Kuniva Abe Lorraine Flaherty Dorothea Bennett Karen Artzt 《Mammalian genome》1991,1(2):92-99
We have determined the molecular maps of theH-2D andQa regions of thet-complex haplotypest
l2
andt
w5
by chromosomal walking. Analysis with class I probes and other probes unique to theH-2D:Qa subregion indicates that the class I gene organization oft
12
is:D1-D2-Q1-Q2-Q3-Qx-Q4-Q5-Q10, while that oft
w5
is:D1-D2-Q1-Q2-Q4-Q5-Q10. Thus, the absence of theQ6-Q9 genes suggested previously int-haplotypes was confirmed. A comparison of the molecular maps of thet
12
andt
w5
chromosomes revealed an extremely mosaic pattern of diversity: The regions betweenD1 andD2, and betweenQ4 andQ10, are very similar in both chromosomes. However, theirQ1 toQ3 regions are strikingly different. Further comparisons of wild-type chromosomes and additionalt-haplotypes by molecular mapping and genomic Southern blot hybridization with probes to theQ1-Q3 region showed a high level of polymorphism among both wild-type chromosomes and amongt-haplotypes. The characteristics of the polymorphisms suggest that recombination may play an important role in generating
this genetic diversity. Furthermore, recombination between wild-type andt-haplotype chromosomes may be involved. 相似文献
20.
The genome ofLeishmania donovani AG83, a virulent strain causing kala-azar, was resolved into 29 chromosomal bands by pulsed field gel electrophoresis (pFGE)
under standardized conditions. Comparison of the karyotype with those of other strains and species revealed variations. By
Southern hybridization, specific genes were localized to individual chromosomes. Twenty-two copies ofβ-tubulin genes are located on band 27 (1.63 Mb); minor copies are present in band 16 (850 kb) and band 9 (650 kb). Aβ-tubulin related nontranscribed locus was isolated from a genomic library and shown to contain repetitive sequences hybridizing
throughout the genome. Single chromosomes contain multicopy clusters of gp63 and rnini-exon-derived RNA genes, but interspecific
variations were observed in each case. The results emphasize the importance of using a standard reference strain ofLeishmania donovani for coordinated genome mapping of this clinically important organism. 相似文献