Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| in vitro maintenance of leishmania amastigotes directly from lesions: advantages and limitations. | leishmania amazonensis (mhom/br/77/ltb0016) amastigotes were obtained from mouse cutaneous lesions and maintained in vitro for 48 hr at ph 4.6, 33 c. these organisms were reproducing, capable of transformation to promastigotes, and did not display the promastigote-specific antigen, gp46. in contrast, 97% of the organisms maintained for 24 hr at 31 c, ph 7.3, were positive for gp46. thus, short-term cultivation of this l. amazonensis strain under appropriate conditions can provide a high yield of ... | 1997 | 9379307 |
| immune responses induced by a leishmania (leishmania) amazonensis recombinant antigen in mice and lymphocytes from vaccinated subjects. | in the search for leishmania recombinant antigens that can be used as a vaccine against american cutaneous leishmaniasis, we identified a leishmania (leishmania) amazonensis recombinant protein of 33 kd (larp33) which is recognized by antibodies and peripheral blood leukocytes (pbl) from subjects vaccinated with leishvacin, larp33 was expressed in escherichia coli after cloning of a 2.2 kb sau3 digested genomic fragment of l. (l.) amazonensis into the pds56-6 his vector. immunoblotting analysis ... | 1997 | 9394518 |
| accidental leishmania mexicana infection in an immunosuppressed laboratory technician. | a 30 year-old female laboratory technician under immunosuppressive treatment because of systemic lupus erythematosus (sle) developed cutaneous leishmaniasis 8 months after accidental percutaneous inoculation of amastigote culture forms of leishmania mexicana. leishmania-specific pcr and restriction analysis patterns were identical for both the laboratory strain and the clinical specimen. the lesion was resistant to local paromomycin and oral ketoconazole, but responded to local application of me ... | 1997 | 9438471 |
| delineation of three pathways of glycosylphosphatidylinositol biosynthesis in leishmania mexicana. precursors from different pathways are assembled on distinct pools of phosphatidylinositol and undergo fatty acid remodeling. | glycosylphosphatidylinositol (gpi) glycolipids are major cell surface constituents in the leishmania parasites. distinct classes of gpi are present as membrane anchors for several surface glycoproteins and an abundant lipophosphoglycan as well as being the major glycolipids (gipls) in the plasma membrane. in this study we have identified putative precursors for the protein and lipophosphoglycan anchors and delineated the complete pathway for gipl biosynthesis in leishmania mexicana promastigotes ... | 1998 | 9461623 |
| identification of a transcription factor like protein at the tor locus in leishmania mexicana amazonensis. | the tor gene (toxic nucleoside resistance gene) was mapped to a 2.3 kb fragment on the amplified dna from tubercidin resistant leishmania (tub). this dna fragment conferred upon wild type cells resistance to tubercidin, inosine dialdehyde, formycin a and b and allopurinol riboside and a reduced ability to accumulate purine nucleobases and nucleosides. these properties were characteristic of the parental tub cells which carried the intact amplified dna and have been hypothesized to be caused by a ... | 1997 | 9476797 |
| leishmania amazonensis promastigotes evade complement killing by interfering with the late steps of the cascade. | during their growth in vitro, promastigotes of leishmania amazonensis undergo differentiation from complement-susceptible to complement-resistant forms. here, we demonstrate that both forms bind comparable amounts of c3 on their surfaces, with the predominant molecule species being the haemolytically active c3b. likewise, equivalent amounts of c9 are deposited on both forms of promastigotes. however, while c9-bearing complexes are exposed on the cell surface of resistant promastigotes, they are ... | 1997 | 9488871 |
| characterization of mitochondrial electron-transfer in leishmania mexicana. | some general features of the respiratory chain and respiratory control were characterized in coupled mitochondrial preparations from leishmania mexicana promastigotes. o2 uptake was sensitive to the electron-transfer inhibitors rotenone, flavone, malonate, 4,4,4-trifluoro-1-(2-thienyl) 1.3 butanedione (ttfa), antimycin a, 2n-nonyl-4-hydroxyquinoline-n-oxide (hqno), myxothiazol, cyanide and azide. a high concentration of rotenone (60 microm) was required to inhibit o2 uptake effectively. differen ... | 1997 | 9497031 |
| a motility function for the paraflagellar rod of leishmania parasites revealed by pfr-2 gene knockouts. | we demonstrate a functional role for the paraflagellar rod (pfr) in motility of leishmania mexicana. the pfr is a complex cytoskeletal structure running parallel to the axoneme in the flagella of kinetoplastid protozoa. the pfr is composed of a latticework of protein filaments whose major constituents are two related proteins (pfr-1 and pfr-2 in leishmania). the molecular details of their assembly into pfr filaments are unknown as is the biological function of the pfr. as an approach to understa ... | 1997 | 9497035 |
| organization, sequence and stage-specific expression of the phosphoglycerate kinase genes of leishmania mexicana mexicana. | in leishmania mexicana two genes were detected coding for different isoforms of the glycolytic enzyme phosphoglycerate kinase. this situation contrasts with that observed in other trypanosomatidae (trypanosoma brucei, trypanosoma congolense, crithidia fasciculata) analyzed previously, which all contain three different genes coding for isoenzymes a, b and c, respectively. all attempts to detect in l. mexicana a type a pgk, or a gene encoding it, proved unsuccesful. we have cloned and characterize ... | 1997 | 9497040 |
| cloning and functional analysis of the ribonucleotide reductase gene small subunit from hydroxyurea-resistant leishmania mexicana amazonensis. | 1997 | 9497060 | |
| trypanosomatidae produce acetate via a mitochondrial acetate:succinate coa transferase. | hydrogenosome-containing anaerobic protists, such as the trichomonads, produce large amounts of acetate by an acetate:succinate coa transferase (asct)/succinyl coa synthetase cycle. the notion that mitochondria and hydrogenosomes may have originated from the same alpha-proteobacterial endosymbiont has led us to look for the presence of a similar metabolic pathway in trypanosomatids because these are the earliest-branching mitochondriate eukaryotes and because they also are known to produce aceta ... | 1998 | 9501211 |
| new world cutaneous leishmaniasis imported into australia. | a case of cutaneous leishmaniasis in a traveller from belize, central america is reported. leishmaniasis presents rarely in australia and delays in diagnosis and treatment often occur. a high index of suspicion in a patient who has returned from an endemic region is required. subsequent confirmation of a diagnosis of cutaneous leishmaniasis is best achieved by demonstration of the organism on skin biopsy, aspiration or smear. the histology is variable and depends on geographic, parasite species ... | 1998 | 9534213 |
| characterisation of leishmania telomeres reveals unusual telomeric repeats and conserved telomere-associated sequence. | characterisation of the telomeres of leishmania is important for understanding many aspects of the parasitic life of this primitive protozoan and for the completion of the physical map and sequencing of the genome. after sequencing more than 300 telomere-derived clones from leishmania braziliensis and leishmania major, a conserved 100 bp sequence was identified immediately adjacent to the telomere at the chromosome end and was named lctas (leishmania conserved telomere-associated sequence). the ... | 1998 | 9547275 |
| the crk3 gene of leishmania mexicana encodes a stage-regulated cdc2-related histone h1 kinase that associates with p12. | a cdc2-related protein kinase gene, crk3, has been isolated from the parasitic protozoan leishmania mexicana. data presented here suggests that crk3 is a good candidate to be the leishmanial cdc2 homologue but that the parasite protein has some characteristics which distinguish it from mammalian cdc2. crk3 is predicted to encode a 35.6-kda protein with 54% sequence identity with the human cyclin-dependent kinase cdc2 and 78% identity with the trypanosoma brucei crk3. the trypanosomatid crk3 prot ... | 1998 | 9553063 |
| leishmania amazonensis: the phagocytosis of amastigotes by macrophages. | in the present study, we examine the cell biology of leishmania amastigote uptake by mammalian cells and compare this process to the phagocytosis of igg-opsonized erythrocytes. we report that many aspects of amastigote uptake into macrophages resemble classical receptor-mediated phagocytosis. parasite uptake requires energy expenditure by macrophages but not by parasites. treating macrophages to prevent either energy metabolism or actin polymerization prevents amastigote uptake. the uptake of am ... | 1998 | 9562419 |
| a mitogen-activated protein (map) kinase homologue of leishmania mexicana is essential for parasite survival in the infected host. | the parasitic protozoon leishmania mexicana undergoes two major developmental stages in its life cycle exhibiting profound physiological and morphological differences, the promastigotes in the insect vector and the amastigotes in mammalian macrophages. a deletion mutant, deltalmsap1/2, for the secreted acid phosphatase (sap) gene locus, comprising the two sap genes separated by an intergenic region of approximately 11.5 kb, lost its ability to cause a progressive disease in balb/c mice. while in ... | 1998 | 9564044 |
| sensitivity of leishmania spp. to glibenclamide and 4-aminopyridine: a tool for the study of drug resistance development. | we have demonstrated that leishmania spp. grown as promastigotes, are sensitive to the k+ channel inhibitors 4-aminopyridine and glibenclamide. their host cells, the macrophages, are not affected by similar concentrations of the drugs. we have also initiated the molecular characterization of the mechanisms involved in the development of drug resistance to glibenclamide by the parasite. therefore, we have selected experimentally and begun to characterize the venezuelan leishmania (leishmania) str ... | 1997 | 9566226 |
| crystal structure of leishmania mexicana glycosomal glyceraldehyde-3-phosphate dehydrogenase in a new crystal form confirms the putative physiological active site structure. | the structure of glycosomal glyceraldehyde-3-phosphate dehydrogenase (gapdh) from the trypanosomatid parasite leishmania mexicana in a new crystal form has been determined by x-ray crystallography. the protein crystallizes in space group p21 with one 156 kda tetramer per asymmetric unit. the model of the protein with bound nad+s and phosphates has been refined against 81% complete data from 10.0 to 2. 8 a to a crystallographic rfactor of 0.217. the present structure confirms two key aspects of t ... | 1998 | 9571030 |
| rapid identification of leishmania species from formalin-fixed biopsy samples by polymorphism-specific polymerase chain reaction. | the precise identification and classification of leishmania species is important for public health surveillance since different species cause different clinical features of the disease. a highly specific polymerase chain reaction (pcr) panel was developed to enable the identification of the five major leishmania species that cause new world cutaneous leishmaniases. the primers used for this panel were designed to distinguish the polymorphism in sequences of commonly amplified dna bands of the pa ... | 1998 | 9573358 |
| isoenzyme characterization of leishmania isolated from human cases with localized cutaneous leishmaniasis from the state of campeche, yucatan peninsula, mexico. | seventy-five isolates from the state of campeche, mexico, an area endemic for localized cutaneous leishmaniasis (lcl), were characterized by isoenzyme markers (glucose phosphate isomerase, mannose phospate isomerase, nucleoside hydrolase, phosphoglucomutase, 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase). seventy (93.3%) were identified as leishmania (leishmania) mexicana and 5 (6.7%) as l. (viannia) braziliensis. this is the first report of authochthonus human lcl caus ... | 1998 | 9574789 |
| reactivation of triosephosphate isomerase from three trypanosomatids and human: effect of suramin. | the reactivation of the homodimeric triosephosphate isomerases (tims) from trypanosoma brucei, t. cruzi, leishmania mexicana and humans was determined after their denaturation with guanidine hydrochloride. in the range of 2-32 microg of t. brucei tim per ml and 0.2-5 microg of the other enzymes per ml, the rate and extent of tim reactivation depended on protein concentration, indicating that at these protein concentrations, the rate-limiting step of reactivation is monomer association and not mo ... | 1998 | 9576855 |
| cloning of a cdc2-related protein kinase from trypanosoma cruzi that interacts with mammalian cyclins. | two cdc2-related protein kinases (crk), tzcrk3 and tzcrk1, from the protozoan parasite trypanosoma cruzi were cloned. tzcrk3 encodes a 35 kda protein sharing 51.5% amino acid identity with human cdc2 and 82% identity with trypanosoma brucei crk3. tzcrk1 encodes a 33 kda protein sharing 52.7% identity with human cdc2 and a high degree of identity (> 78%) with t. brucei crk1, leishmania mexicana crk1 and trypanosoma congolense crk1. a recombinant tzcrk1 protein was able to phosphorylate histone hi ... | 1998 | 9580532 |
| in vitro stimulation of metacyclogenesis in leishmania braziliensis, l. donovani, l. major and l. mexicana. | promastigotes of leishmania braziliensis, l. donovani, l. major and l. mexicana recently derived from tissue amastigotes were cultured in schneider's drosophila medium supplemented with 20% (v/v) heat-inactivated foetal calf serum and 25 micrograms gentamicin sulfate/ml at ph 5.5. these cultures produced more metacyclic promastigotes in their stationary-phase populations than others cultured at ph 7.0. metacyclic promastigotes possessed a short (< or = 8 microns) and narrow (< or = 1.5 microns) ... | 1998 | 9585932 |
| phenotypic characterization of leishmania mexicana pentamidine-resistant promastigotes. modulation of the resistance during in-vitro developmental life cycle. | two clones of leishmania mexicana resistant to 5 microm (lmr5cl2) and 20 microm (lmr20cl1) pentamidine, derived from a parental wild-type clone (lmwtcl3) were selected in vitro using a continuous drug pressure protocol. both resistant clones expressed a cross-resistance to diminazene aceturate. no differences in their in-vitro infectivity for mouse peritoneal macrophages between wild-type and pentamidine-resistant promastigotes were observed. during these experiments, promastigotes of lmr20cl1 d ... | 1997 | 9587476 |
| stage-specific proteophosphoglycan from leishmania mexicana amastigotes. structural characterization of novel mono-, di-, and triphosphorylated phosphodiester-linked oligosaccharides. | intracellular amastigotes of the protozoan parasite leishmania mexicana secrete a macromolecular proteophosphoglycan (appg) into the phagolysosome of their host cell, the mammalian macrophage. the structures of appg glycans were analyzed by a combination of high ph anion exchange high pressure liquid chromatography, gas chromatography-mass spectrometry, enzymatic digestions, electrospray-mass spectrometry as well as 1h and 31p nmr spectroscopy. some glycans are identical to oligosaccharides know ... | 1998 | 9593686 |
| molecular characterization of a carbamoyl-phosphate synthetase ii (cps ii) gene from leishmania mexicana. | 1998 | 9598066 | |
| leishmania amazonensis: long-term cultivation of axenic amastigotes is associated to metacyclogenesis of promastigotes. | axenic leishmania amazonensis cultures were obtained (with 2 years of follow-up) in schneider's medium at ph 5.5 and a temperature of 32 degrees c. differentiation of promastigotes into amastigotes is directly associated with the metacyclogenesis rate of the original promastigotes. promastigote cultures containing different percentages of metacyclic forms, as evaluated by the complement lysis test, resulted in axenic amastigote cultures containing a variable amount of undifferentiated forms. we ... | 1998 | 9603489 |
| sex-determined resistance against leishmania mexicana is associated with the preferential induction of a th1-like response and ifn-gamma production by female but not male dba/2 mice. | female dba/2 mice are relatively resistant to infection with leishmania mexicana compared with male mice. following subcutaneous infection with 5 x 10(6) l. mexicana, amastigotes lesion growth in male and female dba/2 mice was measured and the developing immune responses were monitored both in vitro and in vivo. over the 10 week duration of the experiment all male dba/2 mice developed rapidly growing non-healing lesions while female mice either developed no lesions whatsoever or developed smalle ... | 1998 | 9619486 |
| characterization of a novel translational inhibitor from leishmania mexicana promastigotes. | an inhibitory activity blocking protein synthesis elongation in several eukaryotic systems has been detected in leishmania mexicana extracts. this factor, which competes with aminoacylation of trna and also affects the subsequent polymerization step, is a strong inhibitor of polypeptide synthesis induced by poly u in wheat-germ extracts or by endogenous mrnas in rat liver cell-free systems. the purified translational inhibitor has shown to be essentially free of proteins. several chemical and bi ... | 1998 | 9620444 |
| partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm riftia pachyptila. | we report here the structural determination of n-linked oligosaccharides found on extracellular hemoglobins of the hydrothermal vent tube worm riftia pachyptila. structures were elucidated by a combination of electrospray ionization tandem mass spectrometry, matrix-assisted laser desorption/ionization mass spectrometry, normal-phase high performance liquid chromatography, and exoglycosidase digestion. the sugar chains were found to consist mainly of high-mannose-type glycans with some structures ... | 1998 | 9621107 |
| heterogeneity and a coiled coil prediction of trypanosomatid-like flagellar rod proteins in euglena. | the emergent flagellum of euglenoids and trypanosomatids contained in addition to microtubules a prominent filamentous structure--the flagellar rod (paraflagellar/paraxonemal rod). immunoblots and immunofluorescence localization using three antibodies generated against gel-isolated proteins confirmed previous studies that the euglena flagellar rod consisted of polypeptides migrating at 66-, 69-, and 75-kd. immunoblotting after two dimensional gel electrophoresis identified ten or more isoforms o ... | 1998 | 9627992 |
| insulin-like growth factor-i induces phosphorylation in leishmania (leishmania) mexicana promastigotes and amastigotes. | protein phosphorylation controls major steps of proliferation and differentiation in eukaryotic cells. however there are few studies done in protozoa particularly when being triggered by external stimuli. in this paper we have examined the tyrosine- and serine/threonine-phosphorylated proteins in both promastigote and amastigote-like forms of leishmania (leishmania) mexicana stimulated with insulin-like growth factor (igf)-i. stimulation with igf-i induces major tyrosine phosphorylation of a 185 ... | 1998 | 9627996 |
| leishmania (leishmania) amazonensis: purification and enzymatic characterization of a soluble serine oligopeptidase from promastigotes. | a soluble proteinase was purified 90-fold from extracts of promastigotes of leishmania (leishmania) amazonensis using a combination of ion-exchange chromatography in q-sepharose fast flow, gel filtration chromatography in sephacryl hr s-200, and chromatofocusing. the enzyme appeared as a single band with an apparent molecular weight of 101 kda by silver staining following sds-page, under both reducing and nonreducing conditions. the proteinase has a ph optimum between 8.0 and 8.5 and an isoelect ... | 1998 | 9635438 |
| genus-specific expression from the sl rna promoter of leishmania amazonensis. | 1998 | 9635452 | |
| single-step multiplex pcr assay for characterization of new world leishmania complexes. | we have developed a pcr assay for one-step differentiation of the three complexes of new world leishmania (leishmania braziliensis, leishmania mexicana, and leishmania donovani). this multiplex assay is targeted to the spliced leader rna (mini-exon) gene repeats of these organisms and can detect all three complexes simultaneously, generating differently sized products for each complex. the assay is specific to the leishmania genus and does not recognize related kinetoplastid protozoa, such as tr ... | 1998 | 9650950 |
| sulfhydryl reagent susceptibility in proteins with high sequence similarity--triosephosphate isomerase from trypanosoma brucei, trypanosoma cruzi and leishmania mexicana. | the amino acid sequence of triosephosphate isomerase from trypanosoma brucei, trypanosoma cruzi, and leishmania mexicana have an identity of 68%. using the numbering system for the t. brucei enzyme, in their aligned sequences, the t. cruzi and leishmanial enzymes have cysteine residues at positions 14, 40, 117 and 126. t. brucei triosephosphate isomerase has cysteine residues at positions 14, 40 and 126, and a valine residue at position 117. dithionitrobenzoic acid and methylmethane thiosulfonat ... | 1998 | 9654066 |
| immunogenicity of a salmonella typhi cvd 908 candidate vaccine strain expressing the major surface protein gp63 of leishmania mexicana mexicana. | attenuated salmonella typhi are attractive for use as live vector vaccines to express protozoal antigens and deliver them to the human immune system. the gene encoding the mature form of leishmania mexicana mexicana gp63 under control of tac promoter was integrated into the delta aroc locus of the chromosome of attenuated delta aroc, delta arod s. typhi strain cvd 908. after oral immunization of balb/c mice with two 1 x 10(9) colony forming unit doses given 21 days apart, cvd 908 omega (delta ar ... | 1998 | 9682357 |
| response to heterologous leishmanins in cutaneous leishmaniasis in nigeria--discovery of a new focus. | a pilot study was undertaken to preliminary illustrate the leishmanin skin test (lst) positivity to distinct antigen preparations (derived from promastigote of either leishmania major or l. amazonensis, or pooled l. mexicana, l. amazonensis and l. guyanensis) in cutaneous leishmaniasis (cl) patients and healthy subjects living in two endemic foci in nigeria. the study was designed to provide insights into whether cross-species leishmanin, such as that prepared from new world leishmania could be ... | 1998 | 9698838 |
| in vitro method for isolation of amastigote forms of leishmania amazonensis from j774g8 macrophage induced by temperature shifting. | 1998 | 9698849 | |
| phase 1 study of an inactivated vaccine against american tegumentary leishmaniasis in normal volunteers in brazil. | a phase 1 double-blind placebo-controlled study was performed to evaluate a vaccine against american tegumentary leishmaniasis in 61 healthy male volunteers. side effects and the immune response to the vaccine were evaluated, with 1- and 2- dose schemes, with intervals of 7 or 21 days, each dose containing 1440 mg of protein n antigen of a single strain of leishmania amazonensis (ph8) diluted in merthiolated saline (1:10,000). merthiolated saline and an inert substance were used as placebos. no ... | 1998 | 9698895 |
| purification and partial characterization of trypanosoma cruzi triosephosphate isomerase. | the enzyme triosephosphate isomerase (tpi, ec 5.3.1.1) was purified from extracts of epimastigote forms of trypanosoma cruzi. the purification steps included: hydrophobic interaction chromatography on phenyl-sepharose, cm-sepharose, and high performance liquid gel filtration chromatography. the cm-sepharose material contained two bands (27 and 25 kda) with similar isoelectric points (pi 9.3-9.5) which could be separated by gel filtration in high performance liquid chromatography. polyclonal anti ... | 1998 | 9698898 |
| a gene encoding the plant-like alternative oxidase is present in phytomonas but absent in leishmania spp. | the constituents of the respiratory chain are believed to differ among the trypanosomatids; bloodstream stages of african trypanosomes and phytomonas promastigotes oxidize ubiquinol by a ubiquinol:oxygen oxidoreductase, also known as alternative oxidase, whereas leishmania spp. oxidize ubiquinol via a classic cytochrome-containing respiratory chain. the molecular basis for this elementary difference in ubiquinol oxidation by the mitochondrial electron-transport chain in distinct trypanosomatids ... | 1998 | 9703678 |
| modification of kinetoplast dna minicircle composition in pentamidine-resistant leishmania. | pentamidine, an antiprotozoal drug, was shown to have various cellular and molecular targets depending on the organism. in leishmania, ultrastructural modifications of kinetoplast and mitochondria have been observed but no data is available on cellular and molecular events involved in development of pentamidine-resistance. the absence of modification of minicircle dna in pentamidine treated l. donovani and l. amazonensis promastigotes suggested that topoisomerase ii activity is not a target. thi ... | 1998 | 9707364 |
| leishmania amazonensis infection is reduced in macrophages treated with guanine ribonucleosides. | 1998 | 9707370 | |
| leishmania mexicana: extracellular proton concentration is a key regulator of cysteine proteinase cpb expression. | the purpose of this work was to determine which parameters trigger expression of proteins that are potentially important for the differentiation of leishmania mexicana from the promastigote to the amastigote stage. to this effect, a protein-free axenic incubation system was used that supported the differentiation of l. mexicana promastigotes into amastigotes at 33 degreesc and at acidic ph. the predominant modification detected in sds-page patterns of extracted soluble proteins was the appearanc ... | 1998 | 9709031 |
| phagocytosis of leishmania mexicana amastigotes by macrophages leads to a sustained suppression of il-12 production. | healing of leishmaniases is dependent on activation of parasitized macrophages (mphi) by ifn-gamma, which is secreted by leishmania-specific th1 cells. il-12 enhances ifn-gamma production by th1 cells and is crucial for cure. the host cells of leishmania sp., mphi, are a main source of il-12 in vivo. we report that infection of quiescent murine mphi with l. mexicana or l. major amastigotes does not induce il-12 production. moreover, infection suppresses il-12 secretion by mphi activated by lps, ... | 1998 | 9710224 |
| mixed infection of human u-937 cells by two different species of leishmania. | mixed infections by different leishmania species could explain differences in the clinical course of these infections. moreover, mixed infections of the same macrophage could be the basis for parasite recombination. we stained three strains of leishmania (l. mexicana amazonensis, l. donovani dd8, and l. infantum d2, respectively) with different fluorescent dyes and analyzed them using a fluorescence-activated cell scanner. the simultaneous infection of one cell by leishmania belonging to two dif ... | 1998 | 9715931 |
| the effects of protein farnesyltransferase inhibitors on trypanosomatids: inhibition of protein farnesylation and cell growth. | attachment of the prenyl groups farnesyl and geranylgeranyl to specific eukaryotic cell proteins by protein prenyltransferases is required for the functioning of a number of cellular processes including signal transduction. in this study it was found that previously reported inhibitors of mammalian protein farnesyltransferase (pft) [those that mimic the substrate farnesyl pyrophosphate and those that mimic the protein acceptor of the farnesyl group (caax mimetic)] inhibit in vitro farnesylation ... | 1998 | 9719512 |
| south american cutaneous leishmaniasis: report of ten cases in israeli travelers. | cutaneous south american leishmaniasis is caused by several species of leishmaniasis. lack of appropriate treatment may lead to mucocutaneous leishmaniasis, mainly with l. b. braziliensis and l. b. panamensis. | 1998 | 9731963 |
| structure of a filamentous phosphoglycoprotein polymer: the secreted acid phosphatase of leishmania mexicana. | the insect stage of the protozoan parasite leishmania mexicana secretes a filamentous acid phosphatase (secreted acid phosphatase, sap), a polymeric phosphoglycoprotein. the wild-type (wt) sap filament is a copolymer composed of two related gene products sap1 and sap2, which are identical in the enzymatically active nh2-terminal domain and the cooh-terminal domain, but differ in the length of a highly glycosylated ser/thr-rich repeat region (32 amino acids and 383 amino acids, respectively) whic ... | 1998 | 9733646 |
| carbamoyl-phosphate synthetase ii in kinetoplastids. | genes for carbamoyl-phosphate synthetase ii (cps ii), the first enzyme of de novo pyrimidine biosynthesis, were cloned from kinetoplastids, trypanosoma cruzi and leishmania mexicana. t. cruzi cps ii gene encodes a protein of 1524 amino acids that encompasses the glutaminase and cps domains, but incorporates neither aspartate carbamoyltransferase nor dihydroorotase. the residue corresponding to lysine 993 of escherichia coli cps, a residue that characterizes the cps inhibited by ump and that is r ... | 1998 | 9748664 |
| transformation, development, and transmission of axenically cultured amastigotes of leishmania mexicana in vitro and in lutzomyia longipalpis. | axenic cultures of leishmania mexicana amastigotes were transformed to promastigotes in vitro and in vivo in lutzomyia longipalpis. in vitro, both exponential phase and stationary phase amastigotes were capable of transforming and growing as promastigotes, but exponential phase amastigotes completed this transition more quickly. in vivo, both populations were capable of establishing infections in sand flies by membrane feeding and could be transmitted to balb/c mice via bite. a variety of morpho ... | 1998 | 9749637 |
| efficacies of ky62 against leishmania amazonensis and leishmania donovani in experimental murine cutaneous leishmaniasis and visceral leishmaniasis. | current therapy for leishmaniasis is unsatisfactory because parenteral antimonial salts and pentamidine are associated with significant toxicity and failure rates. we examined the efficacy of ky62, a new, water-soluble, polyene antifungal, against cutaneous infection with leishmania amazonensis and against visceral infection with leishmania donovani in susceptible balb/c mice. mice were infected with l. amazonensis promastigotes in the ear pinna and in the tail and were treated with ky62 or amph ... | 1998 | 9756753 |
| protein farnesyltransferase from trypanosoma brucei. a heterodimer of 61- and 65-kda subunits as a new target for antiparasite therapeutics. | we have previously shown that protein prenylation occurs in the trypanosomatids trypanosoma brucei (t. brucei), trypanosoma cruzi, and leishmania mexicana and that protein farnesyltransferase (pft) activity can be detected in cytosolic extracts of insect (procyclic) form t. brucei. a pft that transfers the farnesyl group from farnesyl pyrophosphate to a cysteine that is 4 residues upstream of the c terminus of the ras gtp-binding protein ras1-cvim has now been purified 60,000-fold to near homoge ... | 1998 | 9756885 |
| differential regulation of multiple glucose transporter genes in leishmania mexicana. | we have studied the structure and expression of glucose transporter genes in the parasitic protozoan leishmania mexicana. three distinct glucose transporter isoforms, lmgt1, lmgt2, and lmgt3, are encoded by single copy genes that are clustered together at a single locus. quantitation of northern blots reveals that lmgt2 mrna is present at approximately 15-fold higher level in promastigotes, the insect stage of the parasite life cycle, compared with amastigotes, the intracellular stage of the lif ... | 1998 | 9786920 |
| insulin-like growth factor i is a growth-promoting factor for leishmania promastigotes and amastigotes. | leishmaniases are diseases caused by protozoa of the genus leishmania that affect more than 20 million people in the world. the initial phase of the infection is fundamental for either the progression or control of the disease. the leishmania parasites are injected in the skin as promastigotes and then, after been phagocytized by the host macrophages, rapidly transform into amastigotes. in this phase different nonspecific cellular and humoral elements participate. we have shown previously that i ... | 1998 | 9789067 |
| subverted transferrin trafficking in leishmania-infected macrophages. | the intracellular fate of human transferrin (htf) in macrophages infected by leishmania was investigated. binding of htf-gold complexes at 4 degrees c was competitively inhibited by native holohtf but not by apohtf. infected and uninfected macrophages displayed rather distinct htf trafficking. pulse-chase experiments using uninfected macrophages loaded with 15-nm gold-conjugated bovine serum albumin (bsa) and then incubated with 5-nm gold-conjugated htf revealed a remarkable segregation of these ... | 1998 | 9797066 |
| a new focus of cutaneous leishmaniasis due to leishmania amazonensis in a sub andean region of bolivia. | we detected a new outbreak focus with high incidence of cutaneous leishmaniasis in the sub andean region of la paz. this area was never considered previously as an endemic zone of leishmaniasis. leishmania stocks from human lesions were isolated: three stocks were explored by pulse field gradient electrophoresis, showing evidence for their affiliation to the l. mexicana complex. eight stocks were submitted to isoenzyme electrophoresis and compared with five reference strains: l. amazonensis, l. ... | 1998 | 9821459 |
| identification of mexican leishmania species by analysis of pcr amplified dna. | leishmania parasites isolated into culture from patients with lcl or dcl from four different mexican states were characterised using polymerase chain reaction (pcr), hybridisation with specific probes, and isoenzymes. pcr of the parasites showed that 10 of 11 of those isolates were members of the mexicana complex. this was confirmed in seven cases by isoenzymes. restriction enzyme digests of pcr products of mexican isolates showed the isolates to be different from the l.(l.) mexicana reference s ... | 1998 | 9821463 |
| selective tight binding inhibitors of trypanosomal glyceraldehyde-3-phosphate dehydrogenase via structure-based drug design. | glyceraldehyde-3-phosphate dehydrogenase (gapdh) from the sleeping sickness parasite trypanosoma brucei is a rational target for anti-trypanosomatid drug design because glycolysis provides virtually all of the energy for the bloodstream form of this parasite. glycolysis is also an important source of energy for other pathogenic parasites including trypanosoma cruzi and leishmania mexicana. the current study is a continuation of our efforts to use the x-ray structures of t. brucei and l. mexicana ... | 1998 | 9822549 |
| comparative phosphorylation of calmodulin from trypanosomatids and bovine brain by calmodulin-binding protein kinases. | calmodulin (cam), a major intracellular ca2+ receptor protein, has been identified and partially characterized in several trypanosomatids. the amino acid sequences of cam from trypanosoma cruzi and trypanosoma brucei are known, while that from leishmania mexicana is not. cam from t. cruzi contains 18 amino acid substitutions, as compared with cam from bovine brain. in addition, cam from bovine brain contains two tyrosine residues (tyr-99 and tyr-138), while cam from t. cruzi only contains tyr-13 ... | 1998 | 9827017 |
| mice with stat6-targeted gene disruption develop a th1 response and control cutaneous leishmaniasis. | the cutaneous growth of leishmania mexicana was measured in stat6-deficient mice (stat6-/-) and compared with that in similarly infected wild-type (stat6+/+) mice. following s.c. inoculation with 5 x 10(6) amastigotes of l. mexicana into the shaven rump, stat6+/+ mice developed large, nonhealing cutaneous lesions, while stat6-/- mice failed to develop detectable lesions during most of the course of study. as infection progressed, stat6+/+ mice infected with l. mexicana displayed significantly hi ... | 1998 | 9834104 |
| isolation and partial characterization of a broad specificity aminotransferase from leishmania mexicana promastigotes. | a broad specificity aminotransferase (bsat), with high activity with both, aromatic amino acids and aspartate as substrates, was purified to homogeneity from promastigotes of leishmania mexicana by a method involving chromatography on deae-cellulose, red-120-sepharose and mono q, and gel filtration on sephacryl s-200. the purified enzyme showed a single band in sds-polyacrylamide gel electrophoresis, with an apparent molecular mass of 45 kda. since the apparent molecular mass of the native enzym ... | 1998 | 9851609 |
| leishmania mexicana cysteine proteinase-deficient mutants have attenuated virulence for mice and potentiate a th1 response. | leishmania mexicana mutants lacking cysteine proteinase genes cpa (delta cpa), cpb (delta cpb), or both cpa and cpb (delta cpa/cpb) have been generated by targeted gene disruption. delta cpa mutants produce a disease phenotype in balb/c mice close to that of wild-type l. mexicana, but delta cpb mutants are much less infective, producing very slowly growing small lesions, and delta cpa/cpb double mutants do not induce lesion growth. immunologic analysis of ab isotype during infection and splenocy ... | 1998 | 9862710 |
| cd1d-restricted immunoglobulin g formation to gpi-anchored antigens mediated by nkt cells. | immunoglobulin g (igg) responses require major histocompatibility complex (mhc)-restricted recognition of peptide fragments by conventional cd4(+) helper t cells. immunoglobulin g responses to glycosylphosphatidylinositol (gpi)- anchored protein antigens, however, were found to be regulated in part through cd1d-restricted recognition of the gpi moiety by thymus-dependent, interleukin-4-producing cd4(+), natural killer cell antigen 1.1 [(nk1.1)+] helper t cells. the cd1-nkt cell pathway regulated ... | 1999 | 9880256 |
| synthesis and structure-activity relationships of adenosine analogs as inhibitors of trypanosomal glyceraldehyde-3-phosphate dehydrogenase. modifications at positions 5' and 8. | a number of 5', n6- and c8, n6-disubstituted adenosine analogs was synthesized and tested for inhibition of trypanosomal glyceraldehyde 3-phosphate dehydrogenase. the most active compound, n6-(3-methyl-2-butenyl)-8-(2-thienyl)adenosine, had kl of 9 microm and was marginally selective for the parasite enzyme. | 1998 | 9934461 |
| the efficacy of pentamidine combined with allopurinol and immunotherapy for the treatment of patients with diffuse cutaneous leishmaniasis. | a new treatment regimen was tested on patients with incurable diffuse cutaneous leshmaniasis (dcl) infected with leishmania mexicana mexicana in mexico. two patients with advanced stages of the disease were treated with polychemotherapy (pentamidine and allopurinol) combined with recombinant human interferon-gamma (rifn-gamma). for determination of the best medication, parasites isolated from patient lesions were exposed to available drugs both as promastigotes and as intracellular amastigotes. ... | 1999 | 9951957 |
| characterization by pulse-field electrophoresis of a new region of dna amplification containing the m2 subunit of ribonucleotide reductase in hydroxyurea-resistant leishmania. | an extrachromosomal circular dna of of approximately 50-kb size was amplified in the hydroxyurea-resistant variant of leishmania mexicana amazonensis. the amplicon carried the m2 gene of ribonuleotide reductase as part of the gene encoding resistance to hydroxyurea. the amplicon was unstable. it disappeared rapidly as shown in pulse-field gradient electrophoresis gels after reversion of the cells for 20-80 days. this loss of amplified dna was accompanied by a rapid loss of resistance to hydroxyu ... | 1999 | 9951961 |
| parasitophorous vacuoles of leishmania mexicana acquire macromolecules from the host cell cytosol via two independent routes. | the intracellular parasite leishmania survives and proliferates in host macrophages. in this study we show that parasitophorous vacuoles of l. mexicana gain access to cytosolic material via two different routes. (1) small anionic molecules such as lucifer yellow are rapidly transported into the vacuoles by an active transport mechanism that is sensitive to inhibitors of the host cell's organic anion transporter. (2) larger molecules such as fluorescent dextrans introduced into the host cell cyto ... | 1999 | 9973603 |
| purification, characterization, and drug susceptibility of tubulin from leishmania. | past work suggests that tubulin from kinetoplastid parasites may present an excellent drug target. to explore this possibility, tubulin was purified on a milligram scale from leishmania mexicana amazonensis promastigotes by sonication, deae-sepharose chromatography, and one cycle of assembly-disassembly. purified leishmanial tubulin is recognized by commercially available anti-tubulin antibodies and displays concentration dependent assembly in vitro. the vinca site agents vinblastine, maytansine ... | 1999 | 10029309 |
| putative reservoirs of leishmania amazonensis in a sub-andean focus of bolivia identified by kdna-polymerase chain reaction. | 1999 | 10029903 | |
| characterization of a novel gdp-mannose:serine-protein mannose-1-phosphotransferase from leishmania mexicana. | protozoan parasites of the genus leishmania secrete a number of glycoproteins and mucin-like proteoglycans that appear to be important parasite virulence factors. we have previously proposed that the polypeptide backbones of these molecules are extensively modified with a complex array of phosphoglycan chains that are linked to ser/thr-rich domains via a common manalpha1-po4-ser linkage (ilg, t., overath, p., ferguson, m. a. j., rutherford, t., campbell, d. g., and mcconville, m. j. (1994) j. bi ... | 1999 | 10037765 |
| structural and functional analysis of the lamdr1 multidrug resistance gene in leishmania amazonensis. | we determined primary sequences of the lamdr1 gene in leishmania amazonensis, a protozoan parasite that causes cutaneous leishmaniasis. the longest open reading frame encodes 1341 amino acids for a protein consisting of two similar halves, each containing six putative transmembrane domains and one atp-binding domain. the protein has no potential n-glycosylation sites at the extracellular region. the lamdr1 protein was 91 and 78% identical to the closely related ldmdr1 in l. donovani and lemdr1 i ... | 1999 | 10049701 |
| vaccination of mice with a combination of bcg and killed leishmania promastigotes reduces acute trypanosoma cruzi infection by promoting an ifn-gamma response. | the combination of bcg with killed leishmania promastigotes, demonstrated to be efficient in the cure of patients suffering american cutaneous leishmaniasis and in the induction of a long-term immune response in healthy vaccinated volunteers, was tested in balb/c mice infected with trypanosoma cruzi, in comparison to bcg or leishmania alone, and a vehicle (pbs) control. bcg-leishmania vaccination, applied intra-peritoneally 10 and 3 days before t. cruzi trypomastigote inoculation, prolonged the ... | 1999 | 10067703 |
| status of respiration and atp content in arsenite resistant leishmania mexicana amazonensis. | cellular atp and rate of respiration are important for the cell survival. we have analyzed both the parameters in wild type and arsenite resistant leishmania mexicana amazonensis. there was no significant change observed in the rate of respiration and cellular atp content between drug resistant cells (resistance to 30 microm of sodium arsenite) and wild type cells. further, we have tested the effect of higher concentrations (i.e. 100 microm and 500 microm) of sodium arsenite on the atp content o ... | 1999 | 10089157 |
| structure-based design of submicromolar, biologically active inhibitors of trypanosomatid glyceraldehyde-3-phosphate dehydrogenase. | the bloodstream stage of trypanosoma brucei and probably the intracellular (amastigote) stage of trypanosoma cruzi derive all of their energy from glycolysis. inhibiting glycolytic enzymes may be a novel approach for the development of antitrypanosomatid drugs provided that sufficient parasite versus host selectivity can be obtained. guided by the crystal structures of human, t. brucei, and leishmania mexicana glyceraldehyde-3-phosphate dehydrogenase, we designed adenosine analogs as tight bindi ... | 1999 | 10200252 |
| roles of free gpis in amastigotes of leishmania. | glycosylated phosphatidylinositols (gpis) are abundant cell surface molecules of the leishmania. amastigote-specific gpis amgpi-y and amgpi-z, both ethanolamine (etn)-containing glycolipids, were identified in leishmania amazonensis. a paucity of gpi-anchored proteins in amastigotes of l. amazonensis made the kinetoplastid suitable for evaluating the importance of free (i.e. unconjugated to protein or polysaccharide) gpis. a strain deficient in both amgpi-y and amgpi-z was produced by stable tra ... | 1999 | 10215028 |
| successful topical treatment of murine cutaneous leishmaniasis with a combination of paromomycin (aminosidine) and gentamicin. | cutaneous leishmaniasis is presently treated with 20 days of parenteral therapy with a frequently toxic drug (antimony). topical formulations of paromomycin (15%) plus methylbenzethonium chloride (mbcl, 12%) or plus urea (10%) in soft white paraffin have been tested for old and new world disease in humans. we compared the efficacy of a new topical formulation, wr 279,396 (paromomycin [15%] plus gentamicin [0.5%]) to the clinical formulations in the treatment of cutaneous disease in balb/c mice. ... | 1999 | 10219319 |
| experimental treatment with sodium stibogluconate of hamsters infected with leishmania (leishmania) chagasi and leishmania (leishmania) amazonensis. | the present paper reports the experimental treatment of hamsters infected with leishmania chagasi and leishmania amazonensis with sodium stibogluconate (20 mg/kg/day x 20 days). only with l. chagasi did the treatment result in the complete elimination of parasites from the spleen. however, no parasitological cure was achieved in hamsters infected with l. amazonensis. | 1999 | 10228371 |
| structural and mutagenesis studies of leishmania triosephosphate isomerase: a point mutation can convert a mesophilic enzyme into a superstable enzyme without losing catalytic power. | the dimeric enzyme triosephosphate isomerase (tim) has a very tight and rigid dimer interface. at this interface a critical hydrogen bond is formed between the main chain oxygen atom of the catalytic residue lys13 and the completely buried side chain of gln65 (of the same subunit). the sequence of leishmania mexicana tim, closely related to trypanosoma brucei tim (68% sequence identity), shows that this highly conserved glutamine has been replaced by a glutamate. therefore, the 1.8 a crystal str ... | 1999 | 10235625 |
| purification and properties of phosphoglucose isomerases of trypanosoma cruzi. | glucosephosphate isomerase (pgi; ec 5.3.1.9) of trypanosoma cruzi epimastigotes was found in about the same proportion in the glycosome and the cytosol. this subcellular distribution is similar to that of leishmania mexicana, but contrasts with that of t. brucei bloodstream form, where the enzyme is essentially restricted to the glycosome. glucosephosphate isomerase was highly purified from a glycosome-enriched fraction and to about 70% purity from the soluble extract. both enzymes displayed mic ... | 1999 | 10327611 |
| evidence that free gpi glycolipids are essential for growth of leishmania mexicana. | the cell surface of the parasitic protozoan leishmania mexicana is coated by glycosylphosphatidylinositol (gpi)-anchored glycoproteins, a gpi-anchored lipophosphoglycan and a class of free gpi glycolipids. to investigate whether the anchor or free gpis are required for parasite growth we cloned the l.mexicana gene for dolichol-phosphate-mannose synthase (dpms) and attempted to create dpms knockout mutants by targeted gene deletion. dpms catalyzes the formation of dolichol-phosphate mannose, the ... | 1999 | 10329621 |
| protease trafficking in two primitive eukaryotes is mediated by a prodomain protein motif. | trypanosome protozoa, an early lineage of eukaryotic cells, have proteases homologous to mammalian lysosomal cathepsins, but the precursor proteins lack mannose 6-phosphate. utilizing green fluorescent protein as a reporter, we demonstrate that the carbohydrate-free prodomain of a trypanosome cathepsin l is necessary and sufficient for directing green fluorescent protein to the lysosome/endosome compartment. a proper prodomain/catalytic domain processing site sequence is also required to free th ... | 1999 | 10347181 |
| association of lutzomyia columbiana (diptera: psychodidae) with a leishmaniasis focus in colombia due to species of the leishmania mexicana complex. | in colombia, leishmania mexicana has a scattered geographical distribution and no sand fly vectors have been associated with its transmission. during the present study, the anthropophilic sand fly lutzomyia columbiana was found to be the only species collected using diverse methods, in a small focus of le. mexicana in the municipality of samaniego, sw colombia. ecological data indicate that this sand fly species is present in both peri and intradomestic habitats, where it readily bites man. furt ... | 1999 | 10348975 |
| cysteine protease inhibitors as chemotherapy for parasitic infections. | analysis of the evolution, localization and biologic function of papain family cysteine proteases in metazoan and protozoan parasites has provided important and often surprising insights into the biochemistry and cellular function of this diverse enzyme family. furthermore, the relative lack of redundancy of cysteine proteases in parasites compared to their mammalian hosts makes them attractive targets for the development of new antiparasitic chemotherapy. the treatment of experimental models of ... | 1999 | 10353643 |
| down-regulation of marcks-related protein (mrp) in macrophages infected with leishmania. | leishmania, a protozoan parasite of macrophages, has been shown to interfere with host cell signal transduction pathways including protein kinase c (pkc)-dependent signaling. myristoylated alanine-rich c kinase substrate (marcks) and marcks-related protein (mrp, macmarcks) are pkc substrates in diverse cell types. marcks and mrp are thought to regulate the actin network and thereby participate in cellular responses involving cytoskeletal rearrangement. because mrp is a major pkc substrate in mac ... | 1999 | 10358020 |
| energy-dependent efflux from leishmania promastigotes of substrates of the mammalian multidrug resistance pumps. | we demonstrated the existence of three transport activities in promastigotes of leishmania braziliensis, leishmania guyanensis, and leishmania mexicana. the first activity, an energy-dependent efflux of pirarubicin, was observed in all leishmania species and inhibited by verapamil, by 2-[4-(diphenylmethyl)-1-piperazinyl]ethyl-5-(trans-4,6-dimethyl-1, 3,2-dioxaphosphorinan-2-yl)-2,6-dimethyl-4-(3-nitrophenyl)-3-py ridinecarboxylate p oxide (pak104p) and by the phenothiazine derivatives: thioridaz ... | 1999 | 10376995 |
| trypanosoma cruzi and human ubiquitin are immunologically distinct proteins despite only three amino acid difference in their primary sequence. | the high similarity between trypanosoma cruzi and human ubiquitin prompted us to characterize the human humoral immunity to host and parasite ubiquitin in chagas disease and its possible role in chagas autoimmunity. we have used a simplified one step purification procedure to partially purify t. cruzi ubiquitin. using this preparation we have performed elisa and western blots, to show that chagasic sera recognise t. cruzi but not human or leishmania ubiquitin indicating a species-specific respon ... | 1999 | 10378411 |
| pcr-elisa for diagnosis of mucocutaneous leishmaniasis. | in this work we demonstrate that the pcr-elisa technique is sufficiently sensitive and specific for use as a diagnostic test in cases of mucocutaneous leishmaniasis. dna was extracted from cultures of leishmania braziliensis, leishmania infantum, leishmania tropica, leishmania mexicana, trypanosoma cruzi, and blood samples from individuals who presented a clinical diagnosis of leishmaniasis as well as from healthy individuals. the dna was pcr amplified and the product obtained was hybridised wit ... | 1999 | 10379813 |
| lectin-binding properties of different leishmania species. | carbohydrate cell-surface residues on stationary promastigotes of 19 isolates of leishmania were studied with a panel of 27 highly purified lectins, which were specific for n-acetyl-d-glucosamine, d-mannose, l-fucose, d-galactose, n-acetyl-d-galactosamine, and sialic acid. the specificity of the cell-surface carbohydrates was analyzed by agglutination and radioiodinated lectin-binding assays. l. (l.) amazonensis and l. (l.) donovani were agglutinated by 12 and 10 of the 27 lectins used, respecti ... | 1999 | 10382607 |
| typing of leishmania lipophosphoglycans by electrospray mass spectrometry. | a method has been developed to identify the repeating phosphosaccharide units of leishmania lipophosphoglycans using electrospray mass-spectrometry (es-ms). cone voltage-induced fragmentation of intact lipophosphoglycan was found to be as effective as analysis of mild acid hydrolysates in identifying the degree of modification of the repeating units of lipophosphoglycans derived from leishmania mexicana and leishmania major. this finding was exploited in a 'rapid-analysis' method in which a crud ... | 1999 | 10391382 |
| glycosylphosphatidylinositol biosynthetic enzymes are localized to a stable tubular subcompartment of the endoplasmic reticulum in leishmania mexicana. | glycosylphosphatidylinositols (gpi) are essential components in the plasma membrane of the protozoan parasite leishmania mexicana, both as membrane anchors for the major surface macromolecules and as the sole class of free glycolipids. we provide evidence that l.mexicana dolichol-phosphate-mannose synthase (dpms), a key enzyme in gpi biosynthesis, is localized to a distinct tubular subdomain of the endoplasmic reticulum (er), based on the localization of a green fluorescent protein (gfp)-dpms ch ... | 1999 | 10393180 |
| h-2m molecules, like mhc class ii molecules, are targeted to parasitophorous vacuoles of leishmania-infected macrophages and internalized by amastigotes of l. amazonensis and l. mexicana. | in their amastigote stage, leishmania are obligatory intracellular parasites of mammalian macrophages, residing and multiplying within phagolysosomal compartments called parasitophorous vacuoles (pv). these organelles have properties similar to those described for the mhc class ii compartments of antigen-presenting cells, sites where peptide-class ii molecule complexes are formed before their expression at the cell surface. after infection with leishmania amazonensis or l. mexicana, endocytosis ... | 1999 | 10393812 |
| leishmania: overexpression and comparative structural analysis of the stage-regulated meta 1 gene. | the meta 1 gene of leishmania major is upregulated in metacyclic promastigotes and encodes an 11.5-kda protein with no significant similarities to other proteins in the existing databases. in this paper, we characterize the homologous meta 1 genes in l. amazonensis and l. donovani. proteins encoded by this gene in all three species present a high degree of identity. the meta 1 gene cannot be replaced by gene targeting in l. major, suggesting an essential role for the protein, at least in promast ... | 1999 | 10403759 |
| genetic dissection of the leishmania paraflagellar rod, a unique flagellar cytoskeleton structure. | the paraflagellar rod (pfr) is a unique network of cytoskeletal filaments that lies alongside the axoneme in the flagella of most trypanosomatids. while little is known about how two major leishmania mexicana pfr protein components, pfr1 and pfr2, assemble into this complex structure, previous analysis of pfr2 null mutants demonstrated that the pfr is essential for proper cell motility. the structural roles of pfr1 and pfr2 are now examined through comparison of pfr2 null mutants with new pfr1 n ... | 1999 | 10413682 |
| [identification of leishmania tropica mexicana as the etiologic agent of chiclero's ulcer]. | 1999 | 10425830 | |
| leishmania amazonensis infection induces changes in the electrophysiological properties of macrophage-like cells. | whole cell patch-clamp recordings were used to study the electrical properties of the macrophage-like cell line j774.1, after infection with leishmania amazonensis. infection induced a significant increase in cell size and membrane capacitance, suggesting that parasite invasion leads to the addition of plasma membrane to the host cell. by 24 hr after infection, the host cell membrane potential was significantly more hyperpolarized than control cells, and this difference remained for the subseque ... | 1999 | 10430661 |
| comparison of different staining procedures for the flow cytometric analysis of u-937 cells infected with different leishmania-species. | the human macrophage cell line u-937 infected with different leishmania species, leishmania mexicana amazonensis (lma), leishmania donovani (ld) and leishmania infantum (li), was analyzed by flow cytometry (fcm). leishmania spp. were labeled with different stains prior to the infection of the u-937 cells (bcecf-am, pkh2-gl and syto 17) or after the infection (ao, fitc-conjugated monoclonal antibodies, pi). infected cells were analyzed by flow cytometry, fluorescence microscopy and in parallel mi ... | 1999 | 10445312 |
| the structure of pyruvate kinase from leishmania mexicana reveals details of the allosteric transition and unusual effector specificity. | glycolysis occupies a central role in cellular metabolism, and is of particular importance for the catabolic production of atp in protozoan parasites such as leishmania and trypanosoma. in these organisms pyruvate kinase plays a key regulatory role, and is unique in responding to fructose 2,6-bisphosphate as allosteric activator. the determination of the first eukaryotic pyruvate kinase crystal structure in the t-state is reported. a comparison of the leishmania and yeast r-state enzymes reveals ... | 1999 | 10448041 |
| identification of immunodominant antigens in mexican strains of trypanosoma cruzi. | chagas disease represents an important public health problem. in mexico most studies have been performed using trypanosoma cruzi' antigens extracted from strains of other geographical origins. this work was aimed at developing a reactive antigen to perform serological diagnosis of chagas' disease, using mexican t. cruzi strains. we prepared antigenic extracts from epimastigotes, trypomastigotes and sphaeromastigotes of three mexican strains. parasites homogenate was obtained by lysis and sonicat ... | 1999 | 10454003 |