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hydrolysis of l-leucine methyl ester by leishmania mexicana mexicana amastigote cysteine proteinases.the main cysteine proteinases of the amastigote form of leishmania mexicana mexicana were partially purified by gel filtration and ion exchange chromatography. the latter procedure resulted in the separation of some individual cysteine proteinases, as demonstrated by gelatin-sodium dodecyl sulphatepolyacrylamide gel electrophoresis. fractions containing the partially purified proteinases rapidly hydrolysed l-leucine methyl ester to leucine. the activity towards this compound co-eluted with and r ...19921428504
cystatin-like cysteine proteinase inhibitors of parasitic protozoa.a new method has been developed for detecting cystatins and other cysteine proteinase inhibitors. the method, which involves protein separation by sds-page followed by a cysteine proteinase overlay step, is more sensitive than previously reported techniques: as little as 1 ng of recombinant human cystatin c can be detected and cysteine proteinase inhibitors could also be detected in complex protein mixtures such as bovine foetal serum. the method has been used to show, for the first time, cystei ...19921526466
perturbation of sterol biosynthesis by itraconazole and ketoconazole in leishmania mexicana mexicana infected macrophages.the azole antifungals ketoconazole and itraconazole possess in vitro antileishmanial activity against leishmania mexicana mexicana amastigotes in macrophages (cell line j774g8). as in yeast and fungi, the activity is likely to be due to inhibition of the cytochrome p-450-dependent 14 alpha-demethylation of lanosterol and/or 24,25-dihydrolanosterol. indeed, 50% inhibition of ergosterol synthesis was observed at 0.21 microm ketoconazole and 0.15 microm itraconazole. at 5 microm ketoconazole, trace ...19892542790
evidence for a membrane adenosine receptor in leishmania mexicana mexicana (wr 227). 19863020925
phosphomonoesterases of leishmania mexicana mexicana and other flagellates.amastigotes and log-phase promastigotes of leishmania mexicana mexicana contained distinct acid phosphatase, 3'-nucleotidase and 5'-nucleotidase activities, distinguishable by their response to ph and inhibitors. both tartrate-sensitive and tartrate-resistant acid phosphatase were present in the two forms, amastigotes possessed less tartrate-resistant acid phosphatase than promastigotes. a tartrate-sensitive acid phosphatase was secreted into the medium in large amounts during the growth in vitr ...19873037369
isolation of leishmania mexicana mexicana from lutzomyia ylephiletor in guatemala. 19873503412
folate utilisation by leishmania species and the identification of intracellular derivatives and folate-metabolising enzymes.the use and metabolism of folates by leishmanias have been studied by assessing the growth of promastigotes in defined media with different folates and the cell content of folate-metabolising enzymes. the folates present in leishmania mexicana mexicana have been determined using hplc. folic acid, 5-formyltetrahydrofolate (thf) and 5-methyl-thf each supported growth of l. m. mexicana promastigotes in defined medium, whereas the parasites did not survive in the absence of folates; p-aminobenzoic a ...19873574356
host-parasite relationship of leishmania mexicana mexicana and lutzomyia abonnenci (diptera: psychodidae).the life cycle of leishmania mexicana mexicana in the gut of the sand fly, lutzomyia abonnenci, was studied by light and electron microscopy. development was suprapylarian with initial establishment of parasites in the bloodmeal (posterior midgut), and anterior migration of parasites to the cardia/stomodeal valve region beginning at 2.5 days post-infection. flagellates were first observed in the esophagus at 3.5 days, in the posterior armature region of the pharynx at 5 days, and in the anterior ...19873826488
leishmania mexicana mexicana: quantitative analysis of the intracellular cycle.the complete intracellular cycle of the leishmania mexicana mexicana g. s. strain was quantified in human macrophages and in the mouse ic-21 macrophage line utilizing a culture system that allows the direct observation of individual intracellular parasites. a wide range of pre-replicative lag periods exists, implying that promastigotes may be in any phase of their dna synthetic cycle when phagocytosed by the macrophage. amastigotes replicated 2-3 times, after which the host cell died and liberat ...19892608309
ca2+ transport in digitonin-permeabilized trypanosomatids.the use of digitonin to permeabilize leishmania mexicana mexicana, leishmania agamae, and crithidia fasciculata plasma membranes enabled us to study ca2+ transport in situ. the present results show that the mitochondria of these trypanosomatids are able to build up and retain a membrane potential as indicated by a tetraphenylphosphonium-sensitive electrode. ca2+ uptake caused membrane depolarization compatible with the existence of an electrogenically mediated ca2+ transport mechanism in these m ...19902233896
leishmania mexicana mexicana gp63 is a site-specific neutral endopeptidase.leishmania mexicana, like other species of the genus, has a major 63-kda surface glycoprotein (gp63) that is an active protease. reports differ as to whether gp63 is a neutral or an acidic protease. using three radiolabeled synthetic peptide substrates, gp63 purified from l. m. mexicana is most active at ph 6.5-7.5, in three different buffer systems, and appears to be a sequence-specific endopeptidase. the full extent of sequence specificity is undetermined, but these experiments suggest a stron ...19902194121
localized cutaneous leishmaniasis (chiclero's ulcer) in mexico: sensitivity and specificity of elisa for igg antibodies to leishmania mexicana mexicana.sera from 223 human beings were assayed by enzyme-linked immunosorbent assay for immunoglobulin g antibodies to leishmania mexicana mexicana promastigotes. 76% of 74 sera from patients with chiclero's ulcer gave positive reactions at a titre of 1:40; the positivity rate was lower in patients with long-standing infections. false positive reactions were obtained with only 7% of 56 sera from healthy individuals with positive montenegro tests and with 6 of 7 sera from patients with chagas disease. i ...19902124389
[production of monoclonal antibodies against leishmania mexicana mexicana antigens].in the present work we obtained three mabs specific against gp65 of the strain l. mexicana mexicana (nr). these three mabs were able of recognizing promastigotes of l.m.m. not only for immunofluorescence but also by immunostain. in the immunohistochemistry of biopsies of patients with leishmaniasis, using the three mabs, it was possible to observe the presence of amastigotes in the infected tissues.19911843566
differentiation and limited proliferation of isolated leishmania mexicana amastigotes at 27 degrees c.we have demonstrated here that while many amastigotes of both leishmania mexicana amazonensis and leishmania mexicana mexicana differentiate to promastigotes when placed in culture at 27 degrees c, many others remain as amastigotes in their proliferative cycle. we have used this system to examine the effects of the anti-leishmanial compounds amphotericin b, 4-pentenoate and sodium stibogluconate (pentostam) on the proliferation and differentiation of isolated extracellular amastigotes. amphoteri ...19911685870
stage-specific proteinases of leishmania mexicana mexicana promastigotes.four distinct bands of cysteine proteinase activity were detected when stationary-phase populations of leishmania mexicana mexicana were subjected to gelatin-sds-page. the highest mobility band contained at least three isoforms separable by mono q anion exchange chromatography. these high mobility activities were distinct from all the major amastigote enzymes. stationary-phase promastigote populations also contained two acid-activable precursor forms of the promastigote-specific band. it is sugg ...19921521760
diffuse cutaneous leishmaniasis in mexico.in mexico, 6 cases of diffuse cutaneous leishmaniasis (dcl) were found in widely separated geographic regions. information was also available on 2 other cases. in addition to the typical clinical features, half of the patients had evidence of nasopharyngeal mucosal involvement. all isolates from the dcl patients were identified as leishmania mexicana mexicana by isoenzyme analysis and monoclonal antibody typing. in 1 region of tabasco state where dcl was found, uncomplicated cutaneous leishmania ...19892802018
mastomys natalensis as an experimental host for leishmania mexicana mexicana.young multimammate rats (mastomys natalensis) can be readily infected when inoculated intradermally with the amastigotes of leishmania mexicana mexicana. lesions appear at the site of inoculation in the second week of infection and continue to increase in size for the first month; amastigotes can be detected during this period. in the second month, lesions begin to decrease in size and it is more difficult to detect amastigotes. three months after inoculation, the rats show no sign of infection. ...1978653786
effects of thiastearic acids on growth and on dihydrosterculic acid and other phospholipid fatty acyl groups of leishmania promastigotes.thiastearic acid positional isomers (8, 9, 10, 11) were examined for their ability to inhibit population growth and the biosynthesis of a phosphatidylethanolamine cyclopropane fatty acyl group, cis-9,10-methyleneoctadecanoic acid (dihydrosterculic acid), by promastigotes of leishmania species. thiastearic acids are candidate chemotherapeutic agents, since cyclopropane fatty acids are not formed by vertebrate cells. 8- and 10-thiastearic acids strongly inhibited the growth of strains containing t ...19892761573
infection of tissue culture cells of low phagocytic ability by leishmania mexicana mexicana. 19744614724
cutaneous leishmaniasis in guatemala: isoenzyme characterization of isolates from humans.leishmania organisms cultivated from cutaneous lesions of humans in guatemala were characterized by cellulose acetate electrophoresis. six isolates had electrophoretic enzyme patterns identical to world health organization reference strains of leishmania braziliensis braziliensis, and 5 had patterns identical to reference strains of leishmania mexicana mexicana.19883341522
leishmania mexicana: subcellular distribution of enzymes in amastigotes and promastigotes.glycosomes and mitochondrial vesicles from cultured promastigotes of leishmania mexicana mexicana have been separated using isopycnic centrifugation on linear sucrose gradients. hexokinase (ec 2.7.1.2), glucose phosphate isomerase (ec 5.3.1.9), phosphofructokinase (ec 2.7.1.11), glyceraldehyde-3-phosphate dehydrogenase (ec 1.2.1.12), and phosphoenolpyruvate carboxykinase (ec 4.1.1.49) were recovered largely in association with glycosomes (density; 1.215 g/ml). phosphoglycerate kinase (ec 2.7.2.3 ...19853158538
a comparative study of the purine- and pyrimidine-metabolising enzymes of a range of trypanosomatids.a range of trypanosomatids (amastigotes and cultured promastigotes of leishmania mexicana mexicana, cultured promastigotes of l. m. amazonensis, l. donovani and l. tarentolae, culture forms of crithidia fasciculata, herpetomonas muscarum muscarum and h. m. ingenoplastis and procyclic trypomastigotes of trypanosoma brucei brucei) have been surveyed for the presence of purine- and pyrimidine-metabolising enzymes. several common features were observed, including the presence of nucleosidases, catab ...19863015485
inhibition of growth of leishmania mexicana mexicana by leishmania mexicana amazonensis during "in vitro" co-cultivation.inhibition of one leishmania subspecies by exometabolites of another subspecies, a phenomenon not previously reported, is suggested by our recent observations in cell cloning experiments with leishmania mexicana mexicana and leishmania mexicana amazonensis. clones were identified using the technique of schizodeme analysis. the phenomenon observed is clearly relevant to studies of parasite isolation, leishmanial metabolism, cross-immunity and chemotherapy.19872853814
leishmania mexicana: purine-metabolizing enzymes of amastigotes and promastigotes.cultured promastigote and isolated amastigote forms of leishmania mexicana mexicana have been surveyed for the presence of enzymes involved in purine metabolism. quantitative but not qualitative differences between the enzymes of two forms were discovered. there were found to be significant differences between the enzyme content of l. m. mexicana and that reported for l. donovani. extracts of both parasite forms of l. m. mexicana were found to have higher levels of adenine deaminase (ec 3.5.4.2) ...19852982637
characterisation of three groups of cysteine proteinases in the amastigotes of leishmania mexicana mexicana.the multiple cysteine proteinases characteristic of the amastigote forms of leishmania mexicana mexicana have been shown to be of three types. the groups of enzymes are distinguished by their substrate specificities and physical properties and have been purified free from other proteinases and most other proteins. one group (a) comprises at least four enzymes that bind to con a. the cysteine proteinases comprising the other two groups (b and c) were separated by ion exchange chromatography. thes ...19902270108
characterization of glycosyl phosphatidylinositol lipids of parasitic protozoans: leishmania mexicana mexicana promastigotes, trypanosoma cruzi peru epimastigotes and tritrichomonas foetus.glycosyl phosphatidylinositol lipids of cultured l.mex, mexicana lv732 promastigotes, t. cruzi peru epimastigotes and tritrichomonas foetus have been isolated and characterized using metabolic labelling and chromatographic and mass spectrometric (ms) techniques. tlc of the unsaponifiable lipid fractions of l. mex. mexicana and t. cruzi obtained from deae sephadex a-25 followed by iatrobead column chromatography showed three inositol phosphate-containing lipid components. [3h]myo-inositol, [3h]pa ...19902102485
leishmaniasis in brazil: xii. observations on cross-immunity in monkeys and man infected with leishmania mexicana mexicana, l. m. amazonensis, l. braziliensis braziliensis, l. b. guyanensis and l. b. panamensis.cross-immunity trials in monkeys (cebus apella apella) and observations on experimental and natural infections in man confirm the separate identity of l. mexicana mexicana, l. m. amazonensis, l. b. braziliensis, l. b. guyanensis and l. b. panamensis. neither l. m. mexicana nor l. m. amazonensis infections gave protection against subsequent challenge with parasites of the l. braziliensis complex; but recovery from infection with subspecies of l. braziliensis in most cases gave firm resistance to ...1977405504
fusion of host cell secondary lysosomes with the parasitophorous vacuoles of leishmania mexicana-infected macrophages.secondary lysosomes of cultured mouse peritoneal macrophages were labeled with the electron-dense colloid saccharated iron oxide; the identity of the labeled structures was checked by the gomori reaction for acid phosphatase. amastigotes of leishmania mexicana mexicana derived from mouse lesions were used to infect these macrophages in vitro. in electron micrographs of thin sections of infected macrophages the labeled secondary lysosomes were seen fused with the parasitophorous vacuoles without ...1975172627
the surface membrane of leishmania mexicana mexicana: comparison of amastigote and promastigote using freeze-fracture cytochemistry.the freeze fracture replica technique has been used to compare the plasma membranes of amastigote and promastigote stages of leishmania mexicana mexicana with respect to intramembranous particle (integral protein) distribution and to beta-hydroxysterols content as revealed by the distribution of lesions induced by the polyene antibiotic filipin. intramembranous particle (imp) density was greater in promastigote than in amastigote plasma membranes. intramembranous particles were more abundant in ...19863716538
immunoregulatory pathways in murine leishmaniasis: different regulatory control during leishmania mexicana mexicana and leishmania major infections.the effect of whole body sublethal gamma irradiation on the subsequent growth of leishmania mexicana mexicana and leishmania major was studied in cba/ca and balb/c mice. whereas balb/c mice are highly susceptible to both parasites developing non healing progressively growing lesions at the site of cutaneous infection, cba/ca mice develop small healing cutaneous ulcers following subcutaneous infection with l. major but non healing lesions following subcutaneous infection with l.m. mexicana. prior ...19853907906
purine phosphoribosyltransferases of leishmania mexicana mexicana and other flagellate protozoa.amastigotes and cultured promastigotes of leishmania mexicana mexicana and l. m. amazonensis, cultured promastigotes of l. donovani and l. tarentolae, and the culture forms of crithidia fasciculata, herpetomonas muscarum muscarum and h. m. ingenoplastis all possessed four phosphoribosyltransferase (prtase) activities: adenine prtase, hypoxanthine prtase, guanine prtase and xanthine prtase. the enzymes of l. m. mexicana required divalent cations for activity; mn2+ or co2+ produced maximal activit ...19853937660
differences in lsh gene control over systemic leishmania major and leishmania donovani or leishmania mexicana mexicana infections are caused by differential targeting to infiltrating and resident liver macrophage populations.earlier studies had shown that the viscerotropic nih 173 strain of cutaneous leishmania major fails to come under lsh gene control. visceral leishmania donovani lv9 and another viscerotropic cutaneous strain, leishmania mexicana mexicana lv4, are controlled by lsh. the results of double-infection experiments presented here show that expression of lsh resistance against l. mexicana mexicana was enhanced in the presence of l. donovani, whereas l. major still failed to come under lsh gene control, ...19883356462
subcellular localisation of purine-metabolising enzymes in leishmania mexicana mexicana.leishmania mexicana mexicana cultured promastigotes were fractionated by isopycnic centrifugation on linear sucrose gradients. guanine, hypoxanthine and xanthine phosphoribosyltransferase activities were found to be associated with glycosomes, whereas adenine phosphoribosyltransferase was cytosolic. 3'- and 5'-nucleotidases and imp dehydrogenase were shown to be particulate, the former two possibly being associated with the plasma membrane, imp dehydrogenase with the endoplasmic reticulum. nucle ...19854042622
effect of the allylamine antifungal drug sf 86-327 on the growth and sterol synthesis of leishmania mexicana mexicana promastigotes. 19854052119
electrophoretic investigation of some dehydrogenases in leishmania amastigotes.amastigotes of leishmania mexicana mexicana and of leishmania donovani were grown in mouse peritoneal macrophages and dog sarcoma cells in culture. polyacrylamide gel disc electrophoresis of amastigote-infected tissue cultures failed to detect parasite lactate dehydrogenase and malate dehydrogenase, although the presence of glucose-6-phosphate dehydrogenase was indicated.19751155996
amine production by leishmania mexicana.growing promastigotes of leishmania mexicana mexicana excreted large amounts of urea and ammonia into the culture medium. both promastigotes and amastigotes in short-term, high-density cultures also produced urea and ammonia; the excretion rate was higher in promastigotes. putrescine was excreted by growing promastigotes but spermine and spermidine excretion apparently did not occur. both promastigote and amastigote cell extracts contained putrescine and spermidine. both polyamines, but especial ...19854073994
stable ornithine decarboxylase in promastigotes of leishmania mexicana mexicana.studies on the decarboxylation of ornithine in leishmania mexicana have shown that this activity corresponds to a true ornithine decarboxylase rather than to an oxidative decarboxylation or aminotransferase reaction, both of which also give rise to the release of co2. the stoichiometric relationship between substrate and products has indicated that extracts of l. mexicana were able to catalyse the formation of an unknown compound besides putrescine and co2. the addition of cycloheximide to cultu ...19892735921
atypical epidermal alterations in chronic leishmania mexicana mexicana lesions of c3h mice. 19826764518
purification and characterization of proteolytic enzymes of leishmania mexicana mexicana amastigotes and promastigotes.leishmania mexicana mexicana amastigote and promastigote soluble proteinases were purified using gel filtration and ion exchange chromatography. for the amastigotes, two main proteinase activity peaks were separated with both methods. these accounted for approximately 10% and 90% of the total activity. characterization of the two activities for substrate specificity and sensitivity to inhibitors indicated that the major peak from both column methods contained enzymes with the characteristics of ...19846389769
effects of ketoconazole on sterol biosynthesis by leishmania mexicana mexicana amastigotes in murine macrophage tumor cells.murine macrophage tumor cells infected with leishmania mexicana mexicana were exposed to the antimycotic drug ketoconazole and to [2-14c]mevalonate, then the amastigotes were isolated, collected, purified, and their free sterols were analyzed by chromatographic and mass spectrometric methods. control amastigotes contained as products of de novo biosynthesis c28 4-desmethyl sterols (episterol, 5-dehydroepisterol), c29 4-desmethyl sterols (stigmasta-7,24 (28)-dien-3 beta-ol, stigmasta-5,7,24(28)-t ...19863736597
leishmania mexicana: amastigote hydrolases in unusual lysosomes.leishmania mexicana mexicana (m379) amastigotes were found to contain much higher activities than cultured promastigotes of five putative lysosomal enzymes: cysteine proteinase; arylsulfatase (ec 3.1.6.1); beta-glucuronidase (ec 3.2.1.31); dnase (ec 3.1.22.1), and rnase (ec 3.1.27.1). the release profiles of the first three of these enzymes from digitonin-permeabilized amastigotes suggests that they are located within organelles. cytochemical staining for cysteine proteinase, using gold labeled ...19863522261
killing of trypanosoma cruzi and leishmania mexicana, and survival of toxoplasma gondii, in chicken macrophages in vitro.the interaction between trypomastigotes of trypanosoma cruzi, amastigotes of leishmania mexicana mexicana and tachyzoites of toxoplasma gondii with chicken macrophages, obtained by cultivation of blood monocytes, was studied. mouse macrophages were used for comparative purposes. all three protozoa are ingested by chicken macrophages. however, only t. gondii survives within cytoplasmic vacuoles. trypomastigotes of t. cruzi and amastigotes of l. mexicana are destroyed within endocytic vacuoles of ...19853894681
proteinases of leishmania mexicana amastigotes and promastigotes: analysis by gel electrophoresis.the proteinases of leishmania mexicana mexicana amastigotes and promastigotes have been analysed by electrophoresis on polyacrylamide gels containing denatured haemoglobin. eleven bands of activity were detected indicating multiple proteinases. these were significant quantitative and qualitative differences between the proteinases of the two developmental forms. four, b-e, were present in both forms but were of much higher activity in the amastigote. there were two major activities in promastigo ...19817029274
purification of particulate malate dehydrogenase and phosphoenolpyruvate carboxykinase from leishmania mexicana mexicana.the particulate activities of leishmania mexicana mexicana amastigote malate dehydrogenase (l-malate:nad+ oxidoreductase, ec 1.1.1.37) and phosphoenolpyruvate carboxykinase (atp:oxaloacetate carboxy-lyase (transphosphorylating) ec 4.1.1.49) have been purified to apparent electrophoretic homogeneity by hydrophobic interaction chromatography using phenyl-sepharose cl-4b, affinity chromatography using 5'amp-sepharose 4b, and gel filtration using sephadex g-100. malate dehydrogenase was purified 150 ...19853970941
the effect of parasitization by leishmania mexicana mexicana on macrophage function in vitro.macrophages infected with amastigotes of leishmania mexicana mexicana as compared to normal macrophages show decreased migration both randomly and through a 5 microns pore in response to a known chemotaxin, an increased ability to pinocytose and an increased bactericidal ability. unless very heavily parasitized their ability to phagocytose is unaltered. parasitized macrophages are unaltered in their ability to secrete extracellularly lysosomal enzymes, prostaglandins and lysozyme in response to ...19836134450
a comparative study of the utilization of ether- and ester-linked phospholipid-containing liposomes by j774.e1 macrophage cell-line infected with leishmania mexicana mexicana amastigotes.the macrophage cell-line j774.e1 and leishmania m. mexicana infection was used to investigate the uptake of liposomes, which differed in their bulk phospholipid: ester- or ether-analogue of phosphatydilcholine (pc). the receptor-mediated uptake of both species of liposomes, containing native or acetylated ldl as ligands was also evaluated. uninfected and infected j774.e1 cell-line accumulated more ester- and ether-liposomes alone than mixed type (50:50, ester/ether). the utilization was signific ...19947883247
pyruvate kinase of leishmania mexicana mexicana. cloning and analysis of the gene, overexpression in escherichia coli and characterization of the enzyme.leishmania mexicana mexicana contains two tandemly arranged genes for pyruvate kinase (pyk). the 5' located gene codes for a polypeptide with a molecular mass of 54,370. the calculated net charge and isoelectric point of the polypeptide are -6 and 6.5, respectively. its amino-acid sequence is 73.7% identical to that of the trypanosoma brucei pyk and 46.4-49.8% to the enzyme of mammalian cells. the second gene appears not to be functional, because its 5' and 3' extremities have undergone recombin ...19948078522
subcellular distribution and characterization of glucosephosphate isomerase in leishmania mexicana mexicana.the glycolytic enzyme glucosephosphate isomerase (pgi) is present in two different cell compartments of leishmania mexicana promastigotes; more than 90% of the activity was detected in the cytosol, the remainder in glycosomes. this subcellular distribution contrasts with that in trypanosoma brucei, in which the enzyme activity has been mainly located in the glycosomes. pgi was partially purified from l. mexicana cell extracts. throughout the purification procedure only one single pgi activity co ...19947870131
proceedings: infection of cells of low phagocytic ability by promastigote forms of leishmania mexicana mexicana. 19744479409
leishmania mexicana mexicana: attachment and uptake of promastigotes to and by macrophages in vitro.promastigotes of leishmania mexicana mexicana attach to mouse macrophages in vitro in the absence of serum by a wheat germ agglutinin-like ligand on the surface of the promastigote that binds to the n-acetyl glucosamine moiety of a receptor on the surface of the macrophage. the binding is temperature dependent, and the macrophage receptor is trypsin, cytochalasin b, and is assisted or inhibited as for attachment. treatment of promastigotes with proteolytic enzymes uncovers a receptor for a serum ...19836415268
di-o-alkylglycerol, mono-o-alkylglycerol and ceramide inositol phosphates of leishmania mexicana mexicana promastigotes.three acidic unsaponifiable lipid fractions were isolated by chromatographic methods from sandfly vector stages (promastigotes) of a protozoan parasite of man, leishmania mexicana mexicana, cultured in vitro. fast atom bombardment mass spectrometry, fast atom bombardment collision induced tandem mass spectrometry and metabolic labeling were used to characterize these lipids as di-o-alkylphosphatidyl-inositols, lyso-1-o-alkylphosphatidylinositols and inositol phosphosphingolipids. molecular speci ...19883207423
a method for the purification of leishmania promastigotes from infected phlebotomine sandflies.we describe a method for the purification of leishmania promastigotes, isolated from infected sandflies (lutzomyia longipalpis) using a discontinuous density centrifugation gradient (percoll/homem). the sandflies, infected seven days previously with leishmania donovani chagasi or leishmania mexicana mexicana from culture, were homogenized and centrifuged on a percoll discontinuous gradient. five interface bands were formed, and most of the promastigotes settled out at the interface between the ( ...19873675038
electrophoretic analysis of the polypeptides of leishmania amastigotes and promastigotes.the polypeptides of leishmania mexicana mexicana (m379), l. m. amazonensis (lv78), l. major (lv39) and l. d. donovani (lv39) amastigotes and cultured promastigotes have been analysed by sds-polyacrylamide gel electrophoresis. the polypeptide banding patterns of the promastigotes of the four species were quite similar, but distinct differences were detected between those of amastigotes. the results suggest that the various species of leishmania are adapted differently for survival and growth in t ...19863956174
leishmania mexicana: drug sensitivities of promastigotes and transforming amastigotes.a comparison has been made of the effects of a range of antiprotozoal drugs and other metabolic inhibitors upon growing promastigotes and transforming amastigotes of leishmania mexicana mexicana. amastigotes transforming to promastigotes in vitro were highly susceptible to 2-mercaptoacetate, 4-pentenoate, alpha-difluoromethylornithine, ethidium bromide, acridine orange, pentamidine isethionate, allopurinol, amphotericin b, menoctone and pentostam. promastigotes were in most cases less sensitive ...19836833171
the effects of carbon dioxide and oxygen upon the growth and in vitro transformation of leishmania mexicana mexicana.growth of leishmania mexicana promastigotes is highly dependent upon o2 tension. there was a strong positive correlation between the level of o2, growth rate and maximum parasite density. promastigotes under low oxygen tension decreased in size, protein content and motility, and deaths occurred. changes in the carbon dioxide concentration (0.1-5.0%) had little effect on promastigote growth. transformation in vivo of l. mexicana amastigotes to promastigotes also required oxygen, but a low level ( ...19816798439
leishmania mexicana: purine metabolism in promastigotes, axenic amastigotes, and amastigotes derived from vero cells.leishmania mexicana mexicana promastigotes, axenic amastigotes, and amastigotes derived from vero cells were examined for de novo purine synthesis and mechanisms of purine salvage. both promastigotes and axenic amastigotes were incapable of de novo purine synthesis, as shown by the lack of [14c]formate and [14c]glycine incorporation into purine nucleotide pools. however, the ready incorporation of [14c]hypoxanthine, [14c]adenine, and [14c]guanine suggested that purine salvage pathways were opera ...19846745384
enzyme variation and difference in infectivity within a single strain of leishmania mexicana mexicana. 19827076389
successful treatment of cutaneous leishmaniasis with allopurinol after failure of treatment with ketoconazole.treatment of persistent leishmaniasis with oral agents has received increasing attention, although the optimal agent for use in all settings has not been determined. this report describes a patient with persistent cutaneous infection due to leishmania mexicana mexicana who apparently responded to therapy with allopurinol after treatment with a course of ketoconazole failed. in vitro testing of pre- and posttreatment isolates from the wound did not demonstrate the development of resistance to ket ...19948075279
a radioattenuated leishmania major vaccine markedly increases the resistance of cba mice to subsequent infection with leishmania mexicana mexicana.vaccinating cba mice with radioattenuated leishmania major amastigotes but not with radioattenuated l. mexicana mexicana amastigotes rendered them highly resistant to subsequent infection with l. m. mexicana. unvaccinated cba mice were highly susceptible to infection with l. m. mexicana producing rapidly growing non-ulcerating cutaneous lesions. two manifestations of resistance were induced in vaccinated animals depending on the timing of the challenge infection: no lesions appeared at the site ...19827179418
sterols of ketoconazole-inhibited leishmania mexicana mexicana promastigotes.leishmania mexicana mexicana promastigotes grown with cholesterol, supplied in natural products as the free sterol and as cholesteryl esters, were exposed to [2-14c]mevalonate and to the antimycotic drug ketoconazole. growth was inhibited and cholesterol and 14 alpha-methyl sterols accumulated in free and esterified forms (cholesterol much greater than 4 alpha,14 alpha-dimethylcholesta-8,24-dien-3 beta-ol much greater than 14 alpha-methylcholesta-8,24-dien-3 beta-ol congruent to 14 alpha-methyle ...19854033689
proteinase inhibitors as antileishmanial agents.leishmania mexicana mexicana amastigote proteinase activity was largely inhibited by low concentrations of leupeptin, antipain and two epoxysuccinates, compounds known to affect cysteine proteinases. of these inhibitors, only two had leishmanicidal activity. trans-dicyclohexylepoxysuccinate at 10 microgram/ml inhibited the in vitro transformation of l. m. mexicana amastigotes to promastigotes by greater than 50%. antipain was a potent antileishmanial agent, which inhibited promastigote growth ov ...19827179420
identification of leishmania mexicana mexicana in the state of são paulo, brazil. 19836622922
interactions between leishmania mexicana mexicana promastigotes and amastigotes and murine peritoneal macrophages in vitro. 19836645950
host factors influencing outcome of leishmania mexicana mexicana infection in mice. 19836645947
inhibition of leishmania amastigote growth by antipain and leupeptin.antipain and leupeptin were found to be potent inhibitors of the growth of leishmania mexicana mexicana amastigotes in explanted mouse unstimulated peritoneal macrophages. antipain at 100 mg l-1 reduced eight-fold the percentage of macrophages infected and to 5% of the control the number of amastigotes present after seven days incubation. at 1 mg l-1, antipain and leupeptin were as effective antileishmanial agents as pentamidine isethionate, all three stopping parasite multiplication over the se ...19846721611
a comparative study of leishmania mexicana amastigotes and promastigotes. enzyme activities and subcellular locations.leishmania mexicana mexicana amastigotes have been shown to contain greater activities than promastigotes of the enzymes that catalyse the beta-oxidation of fatty acids, but lower activities of several glycolytic enzymes, with the activity of pyruvate kinase being especially low. the results suggest the beta-oxidation of fatty acids is relatively more important to leishmania amastigotes than promastigotes, whereas the reverse is true for glycolysis. succinic dehydrogenase and peptidase activitie ...19826211617
activity of juvenile hormone and juvenile hormone analogues on the growth of trypanosoma cruzi.the effects of juvenile hormone-iii (jh-iii) and the juvenile hormone analogues (jha) methoprene and fenoxycarb on the growth and macromolecular biosynthesis in trypanosoma cruzi were studied in vitro. it was observed that jh-iii and jha blocked growth and 3h-thymidine incorporation without killing the cells within certain concentrations (< or = 1 x 10(-4) m), but they caused cellular death at concentrations over 1 x 10(-3) m. the inhibitory effect on growth was partially reversible. on the othe ...19969010355
tissue eosinophilia and leishmania mexicana mexicana eosinophil interactions in murine cutaneous leishmaniasis.outbred albino mice were infected subcutaneously with 10(6) amastigotes of leishmania mexicana mexicana and the subsequent lesions were evaluated by light and electron microscopy at various intervals after infection. the animals developed persistent nodules and a spectrum of lesions of variable size which was correlated with the host's ability to control the parasite in the tissue. during the acute phase of the disease the histopathological results showed an accumulation of granulocytes, some mo ...19846504555
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 ...19989501211
triose-phosphate isomerase of leishmania mexicana mexicana. cloning and characterization of the gene, overexpression in escherichia coli and analysis of the protein.the gene of triose-phosphate isomerase in leishmania mexicana has been cloned and characterized. the gene encodes a polypeptide of 251 amino acids, with a calculated molecular mass of 27,561 da and a net charge of +2. only one gene could be detected, although the enzyme is present in two different compartments of the cell, in microbody-like organelles called glycosomes and in the cytosol. the primary structure of the enzyme has many features in common with that of triose-phosphate isomerase in t ...19948125090
a comparative study of susceptibility of inbred and outbred mouse strains compared with hamsters to infection with new world cutaneous leishmaniases.one stock of each of leishmania mexicana mexicana and l. m. amazonensis together with two stocks of l. braziliensis panamensis and l. b. braziliensis were tested for infectivity in inbred mouse strains balb/c and cba/h. the infectivity was compared with hamsters and the outbred cd1 mice. balb/c mice were more susceptible than hamsters to l. mexicana and l. braziliensis panamensis. balb/c mice were not susceptible to l. b. braziliensis. cba/h mice showed a low susceptibility to infection while cd ...19836622066
infection of balb/c, c57b1/6 mice and f1 hybrid cb6f1 mice with strains of leishmania mexicana isolated from mexican patients with localized or diffuse cutaneous leishmaniasis.mice from the syngeneic strains balb/c, c57b1/6 and (balb/cxc57b1/6)f1 hybrids (cb6f1) were infected in the footpad with six different strains of leishmania mexicana mexicana isolated from mexican patients. three leishmania strains were isolated from patients with localized cutaneous leishmaniasis (lcl, the benign form of the disease) and three from patients with diffuse cutaneous leishmaniasis (dcl, the malignant form of the disease). in balb/c mice, four leishmania strains showed a sustained f ...19947858398
leishmania mexicana mexicana: genetic heterogeneity of mexican isolates revealed by restriction length polymorphism analysis of kinetoplast dna.leishmania mexicana mexicana isolates from 23 patients with localized, diffuse, and an atypical "pseudodiffuse" form of cutaneous leishmaniasis were obtained in various endemic regions of mexico. restriction fragment length polymorphism analysis of kinetoplast dna was done with nine different endonucleases in addition to an in vitro growth pattern analysis. we found that the 23 l. mexicana mexicana isolates could be consistently classified into six groups, according to the endonuclease digestion ...200011038311
a quick, simple method for purifying leishmania mexicana amastigotes in large numbers.a rapid method for the bulk isolation of purified leishmania mexicana mexicana amastigotes from parasite-induced lesions in experimentally infected mice is described. the procedure includes purification steps based on differences in net cell charge, lysis susceptibility and buoyant density between parasite and host cells. yields of up to 2 x 10(10) untransformed amastigotes with minimal contamination with host cells and cell debris can be obtained. at least 90% of the purified amastigotes are vi ...19817243344
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 ...19979497040
in vitro antitrypanosomal activity of ethnopharmacologically selected beninese plants.the in vitro antitrypanosomal activity of methylene chloride, methanol and aqueous extracts of the leaves and twigs of five plant species traditionally used in benin for the treatment of sleeping sickness were evaluated on trypanosoma brucei brucei and their selectivity was analysed on leishmania mexicana mexicana and j774 macrophage-like murine cells. the results showed that the four most active extracts had mic values < or =19 microg/ml (hymenocardia acida twig and leaf, strychnos spinosa leaf ...200415036465
respiration of leishmania mexicana amastigotes and promastigotes.promastigotes of leishmania mexicana mexicana recently derived from amastigotes by transformation in vitro respired at a rate (17 nmol o2/min per 10(8) parasites) 4-5 times higher than that of amastigotes, but when the difference in cell protein content between the two preparations was taken into account the rates were not significantly different (32 nmol o2/min per mg protein). the respiration of both amastigotes and promastigotes was sensitive to cyanide, azide, antimycin a, 2-n-heptyl-4-hydro ...19817322186
effects of steroidal allenic phosphonic acid derivatives on the parasitic protists leishmania donovani, leishmania mexicana mexicana, and pneumocystis carinii carinii.several pathogenic fungi and protozoa are known to have sterols distinct from those of their mammalian hosts. of particular interest as targets for drug development are the biosyntheses of the sterols of important parasites such as the kinetoplastid flagellates and the aids-associated opportunistic protist pneumocystis carinii. these pathogens synthesize sterols with an alkyl group at c-24, and some have a double bond at c-22 of the side chain. humans and other mammalian hosts are incapable of c ...19978980773
cutaneous leishmaniasis in british troops from belize.the medical records of 306 british soldiers in whom a clinical diagnosis of cutaneous leishmaniasis had been made following a tour of duty in belize were analysed. parasitological confirmation of the diagnosis was established in 187 cases; leishmania were cultured in 117 cases and leishman-donovan bodies were identified histologically in a further 70 cases. leishmania braziliensis braziliensis was identified in 78 cases and leishmania mexicana mexicana in a further 29 cases. seventy-one per cent ...19938381299
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. ...19999951957
cloning and characterization of the nad-linked glycerol-3-phosphate dehydrogenases of trypanosoma brucei brucei and leishmania mexicana mexicana and expression of the trypanosome enzyme in escherichia coli.a polyclonal antiserum raised against the purified glycosomal glycerol-3-phosphate dehydrogenase of trypanosoma brucei brucei has been used to identify the corresponding cdna clone in a t.b. brucei expression library. this cdna was subsequently used to obtain genomic clones containing glycerol-3-phosphate dehydrogenase genes. two tandemly arranged genes were detected in these clones. characterization of one of the genes showed that it codes for a polypeptide of 353 amino acids, with a molecular ...19968920004
comparative study of dna vaccines encoding various antigens against leishmania mexicana.leishmaniases represent an important public health problem in large parts of the world. in the south-east of mexico, the major species isolated from patients is leishmania mexicana mexicana, causing localised cutaneous leishmaniasis, and the development of a vaccine is a key objective for the control of this parasite. we thus performed a comparative study of dna vaccines encoding l. m. mexicana gp63 and cpb, l. m. amazonensis gp46, and l. major lack to define the best antigen(s) candidate(s). cd ...200011713811
in vitro anti-leishmanial activity of essential oils extracted from vietnamese plants.leishmania mexicana is one of the pathogens causing cutaneous leishmaniasis which is associated with patient morbidity. in our researches for new safe and effective treatments, thirty-seven essential oils (eos) extracted from vietnamese plants were screened in vitro for the first time on leishmania mexicana mexicana(lmm) promastigotes at the maximum concentration of 50 nl/ml. active eos were also analyzed for cytotoxicity on mammalian cell lines (wi38, j774) and their selectivity indices (si) we ...201728654013
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 ...19989682357
low serum levels of dehydroepiandrosterone and cortisol in human diffuse cutaneous leishmaniasis by leishmania mexicana.low levels of dehydroepiandrosterone (dhea) and cortisol hormones produced by the suprarenal cortex have been associated with diseases involving chronic inflammation, low interferon (ifn)-gamma, and high interleukin (il)-6. diffuse cutaneous leishmaniasis (dl), a long-lasting intracellular parasitic infectious disease, can spread unknown levels of dhea and cortisol. serum concentrations of both were measured in 5 patients with dl, in 15 patients with localized lesions produced by leishmania (ll) ...200717360885
a novel cdc2-related protein kinase from leishmania mexicana, lmmcrk1, is post-translationally regulated during the life cycle.the p34cdc2 protein kinase is a key component in the regulation of the eukaryotic cell cycle. we have isolated from the protozoan parasite leishmania mexicana mexicana a cdc2-related kinase gene (lmmcrk1) encoding a 34-kda protein kinase (lmmcrk1) which has 56% amino acid identity with the human cdc2 and contains a pctair motif in place of the highly conserved pstair box. lmmcrk1 was detected in all life cycle stages at comparable levels, yet its histone h1 kinase activity was detected in only t ...19938407941
isolation and analysis of a new developmentally regulated gene from amastigotes of leishmania mexicana mexicana.leishmania differentiates from the promastigote to the amastigote stage during its digenetic life cycle. characterization of the developmentally regulated genes during that process would help to elucidate the mechanisms of gene regulation. in this study, specific fragments of mrnas from the amastigote stage of l. mexicana mexicana were discriminated from those of the promastigote and metacyclic stages by differential display. this technique combined with spliced-leader polymerase chain reaction ...200010685845
characterization of the cofactor-independent phosphoglycerate mutase from leishmania mexicana mexicana. histidines that coordinate the two metal ions in the active site show different susceptibilities to irreversible chemical modification.phosphoglycerate mutase (pgam) activity in promastigotes of the protozoan parasite leishmania mexicana is found only in the cytosol. it corresponds to a cofactor-independent pgam as it is not stimulated by 2,3-bisphosphoglycerate and is susceptible to edta and resistant to vanadate. we have cloned and sequenced the gene and developed a convenient bacterial expression system and a high-yield purification protocol. kinetic properties of the bacterially produced protein have been determined (3-phos ...200415096219
leishmania adaptor protein-1 subunits are required for normal lysosome traffic, flagellum biogenesis, lipid homeostasis, and adaptation to temperatures encountered in the mammalian host.the adaptor protein-1 (ap-1) complex is involved in membrane transport between the golgi apparatus and endosomes. in the protozoan parasite leishmania mexicana mexicana, the ap-1 mu1 and sigma1 subunits are not required for growth at 27 degrees c but are essential for infectivity in the mammalian host. in this study, we have investigated the function of these ap-1 subunits in order to understand the molecular basis for this loss of virulence. the mu1 and sigma1 subunits were localized to late go ...200818515754
antitrypanosomal compounds from the essential oil and extracts of keetia leucantha leaves with inhibitor activity on trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase.keetia leucantha is a west african tree used in traditional medicine to treat several diseases among which parasitic infections. the dichloromethane extract of leaves was previously shown to possess growth-inhibitory activities on plasmodium falciparum, trypanosoma brucei brucei and leishmania mexicana mexicana with low or no cytotoxicity (>100 μg/ml on human normal fibroblasts) (bero et al. 2009, 2011). in continuation of our investigations on the antitrypanosomal compounds from this dichlorome ...201323312849
case report: transient success using prolonged treatment with miltefosine for a patient with diffuse cutaneous leishmaniasis infected with leishmania mexicana mexicana.leishmania sp. is an intracellular parasite that causes a variable degree of clinical manifestations, especially in the skin. we present the case of a 38-year-old male with a chronic history of mucocutaneous disease present since childhood that generated deformity, loss of cartilage in the ears and nose, and scarring that limited his range of motion. the parasite was identified as l. mexicana mexicana. the patient was treated with a 3-month course of oral miltefosine with overwhelming results.201323243111
theoretical and in vitro studies of a c-terminal peptide from pgkc of leishmania mexicana mexicana.trypanosomatids cause deadly diseases in humans. of the various biochemical pathways in trypanosomatids, glycolysis, has received special attention because of being sequestered in peroxisome like organelles critical for the survival of the parasites. this study focuses on phosphoglycerate kinase (pgk) from leishmania spp. which, exists in two isoforms, the cytoplasmic pgkb and glycosomal pgkc differing in their biochemical properties. computational analysis predicted the likelihood of a transmem ...201222710389
antiparasitic activities of two sesquiterpenic lactones isolated from acanthospermum hispidum d.c.aerial parts of acanthospermum hispidum d.c. are often used by traditional healers in benin for various diseases and especially for malaria.201222440261
β-adrenergic blockade protects balb/c mice against infection with a small inoculum of leishmania mexicana mexicana (lv4).in order to test the influence of the sympathetic nervous system on leishmania mexicana infection, groups of female balb/c mice were treated (i.p.) with the non-selective β-adrenergic receptor (β-ar) antagonist (s)-propranolol (5mg/kg thrice a day), the β2-ar agonist clenbuterol (1mg/kg once a day) or the α2-ar antagonist yohimbine (2mg/kg twice a day) during 5days. during the second day of treatments, mice were inoculated in the footpad with 1×10(6) or 1×10(3) metacyclic promastigotes of l. mex ...201525461918
natural sesquiterpene lactones induce oxidative stress in leishmania mexicana.leishmaniasis is a worldwide parasitic disease, caused by monoflagellate parasites of the genus leishmania. in the search for more effective agents against these parasites, the identification of molecular targets has been attempted to ensure the efficiency of drugs and to avoid collateral damages on the host's cells. in this work, we have investigated some of the mechanisms of action of a group of natural sesquiterpene lactones that are effective against leishmania mexicana mexicana promastigote ...201323861697
glucose transport in amastigotes and promastigotes of leishmania mexicana mexicana.promastigotes and amastigotes of leishmania mexicana mexicana transported 2-deoxy-d-glucose (2-dog) by a saturable process with a km of 24 +/- 3 microm and vmax of 2.21 nmol min-1 (mg protein)-1 for the promastigote and a km of 29 +/- 8 microm and vmax of 0.13 nmol min-1 (mg protein)-1 for the amastigote stage. amastigotes incorporated 2-dog maximally at ph 5.0, while for promastigotes the optimum was at ph 7.0. mid-log phase promastigotes were found to accumulate 2-dog via a stereospecific carr ...19958719247
leishmania mexicana mexicana glucose-6-phosphate isomerase: crystallization, molecular-replacement solution and inhibition.glucose-6-phosphate isomerase (pgi; ec 5.3.1.9; also often called by its old nomenclature phosphoglucose isomerase) is an intracellular enzyme that catalyses the reversible conversion of d-glucose 6-phosphate (g6p) to d-fructose 6-phosphate (f6p). the native leishmania pgi is a homodimeric molecule of 60 kda per monomer with 47% sequence identity to human pgi. it has been shown to be present in both the cytosol and the glycosome of leishmania promastigotes and represents a potential target for r ...200415103138
in vitro antitrypanosomal and antileishmanial activity of plants used in benin in traditional medicine and bio-guided fractionation of the most active extract.ethnopharmacological relevance: the aim of the study was to evaluate the in vitro antitrypanosomal and antileishmanial activity of crude extracts of 10 plant species traditionally used in benin to treat parasitic infections. materials and methods: for each species, dichloromethane, methanol and aqueous extracts were tested. their antitrypanosomal and antileishmanial activities were evaluated in vitro on trypanosoma brucei brucei (strain 427) (tbb) and on promastigotes of leishmania mexicana mexi ...201121782916
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