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the leishmania hsp20 is antigenic during natural infections, but, as dna vaccine, it does not protect balb/c mice against experimental l. amazonensis infection.protozoa of the genus leishmania are causative agents of leishmaniasis, an important health problem in both human and veterinary medicine. here, we describe a new heat shock protein (hsp) in leishmania, belonging to the small hsp (shsp) family in kinetoplastids. the protein is highly conserved in different leishmania species, showing instead significant divergence with shsp's from other organisms. the humoral response elicited against this protein during leishmania infection has been investigate ...200818401455
antileishmanial activity of azithromycin against leishmania (leishmania) amazonensis, leishmania (viannia) braziliensis, and leishmania (leishmania) chagasi.azithromycin, an azalide antibiotic, is highly concentrated within different phagocytic cells, especially macrophages. the potential antileishmanial activity of azithromycin against three species of leishmania from the new world was assessed using in vitro models. azithromycin decreased viability of promastigote cultures of leishmania (leishmania) amazonensis, leishmania (viannia) braziliensis, and leishmania (leishmania) chagasi as determined by the colorimetric alamar blue assay. in amastigote ...200818458308
interactions with apoptotic but not with necrotic neutrophils increase parasite burden in human macrophages infected with leishmania amazonensis.neutrophils are involved in the initial steps of most responses to pathogens. in the present study, we evaluated the effects of the interaction of apoptotic vs. necrotic human neutrophils on macrophage infection by leishmania amazonensis. phagocytosis of apoptotic, but not viable, neutrophils by leishmania-infected macrophages led to an increase in parasite burden via a mechanism dependent on tgf-beta1 and pge2. conversely, infected macrophages' uptake of necrotic neutrophils induced killing of ...200818483206
characterization of leishmania (leishmania) amazonensis promastigotes resistant to pentamidine.pentamidine is a second-line agent used in the treatment of leishmaniasis and its mode of action and mechanism of resistance is not well understood. it was previously demonstrated that transfection of promastigotes and amastigotes with the abc transporter prp1 gene confers resistance to pentamidine. to further clarify this point, we generated leishmania amazonensis mutants resistant to pentamidine. our results indicated that this abc transporter is not associated with pentamidine resistance in l ...200818511047
down-regulation of dendritic cell signaling pathways by leishmania amazonensis amastigotes.we have previously reported a link between a deficient th1 response to leishmania amazonensis (la) parasites and profound impairments in the cytokine/chemokine network at early stages of the infection. to define the molecular basis of these deficiencies, we focused on early and intracellular events in la-infected dendritic cells (dcs) in this study. la amastigote-infected dcs were less mature and less potent antigen-presenting cells (apc) than their promastigote-infected counterparts, as judged ...200818538399
upgrading the flow-cytometric analysis of anti-leishmania immunoglobulins for the diagnosis of american tegumentary leishmaniasis.we have previously described a flow cytometry-based assay to detect anti-live leishmania (viania) braziliensis promastigote antibodies (fc-alpa) with prominent performance of fc-alpa to diagnosis american tegumentary leishmaniasis (atl). however, the laboriousness to work with live parasites represented the major drawback for using fc-alpa in routine clinical laboratory. herein, we have presented an upgraded technology using fixed leishmania (leishmania) amazonensis promastigotes as antigen (fc- ...200818538785
distinct mitochondrial hsp70 homologues conserved in various leishmania species suggest novel biological functions.we report the identification of two distinct homologues of the 70-kda mitochondrial heat shock protein (mthsp70) from leishmania chagasi/leishmania infantum (lc2.1 and lc2.2). in leishmania species, multiple genes encoding lc2.2 are present whilst single genes encode lc2.1. strikingly, genes encoding lc2.1-like proteins are absent from trypanosoma species. lc2.2 is characterized by a poly-glutamine rich c-terminus, absent from lc2.1 or mthsp70 homologues outside the trypanosomatids. lc2.1 displa ...200818541316
tamoxifen is effective in the treatment of leishmania amazonensis infections in mice.chemotherapy is still a critical issue in the management of leishmaniasis. until recently, pentavalent antimonials, amphotericin b or pentamidine compounded the classical arsenal of treatment. all these drugs are toxic and have to be administered by the parenteral route. tamoxifen has been used as an antiestrogen in the treatment and prevention of breast cancer for many years. its safety and pharmacological profiles are well established in humans. we have shown that tamoxifen is active as an ant ...200818545685
serological reactivity of different antigenic preparations of leishmania (leishmania) amazonensis and the leishmania braziliensis complex.total antigen from leishmania (leishmania) amazonensis and isolates from the leishmania braziliensis complex, along with their respective antigenic fractions obtained by affinity chromatography on concanavalin-a-sepharose and jacalin-agarose columns evaluated using immunoenzymatic elisa assay. for this, serum samples from 229 patients were used, grouped as american tegmental leishmaniasis (n masculine=58), visceral leishmaniasis (n masculine=28), chagas disease (n masculine=49), malaria (n mascu ...200818545832
the use of natural product scaffolds as leads in the search for trypanothione reductase inhibitors.twenty-three heterocyclic compounds were evaluated for their potential as trypanothione reductase inhibitors. as a result, the harmaline, 10-thiaisoalloxazine, and aspidospermine frameworks were identified as the basis of inhibitors of trypanosoma cruzi trypanothione reductase. two new compounds showed moderately strong, linear competitive inhibition, namely n,n-dimethyl-n-[3-(7-methoxy-1-methyl-3,4-dihydro-9h-beta-carbolin-9-yl)propyl]amine (15) and 1,3-bis[3-(dimethylamino)propyl]-1,5-dihydro- ...200818558492
effect of mesoionic 4-phenyl-5-(cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride derivative salts on the activities of the nitric oxide synthase and arginase of leishmania amazonensis.l-arginine is involved in the production of both nitric oxide (no), mediated by nitric oxide synthase (nos) and l-ornithine, by arginase activity. it is generally accepted that no regulation occurs mainly at the transcriptional level of nos. in a previous work we purported that there is evidence that leishmania sp. can produce no from l-arginine. an arginase activity in its gene sequence has also been reported in leishmania parasites. in a search for intracellular targets as potential antileishm ...200818569335
leishmania amazonensis infection may affect the ability of the host macrophage to be activated by altering their outward potassium currents.understanding the impact of intracellular pathogens on the behaviour of their host cells is key to designing new interventions. we are interested in how leishmania alters the electrical functioning of the plasma membrane of the macrophage it infects. the specific question addressed here is whether leishmania amazonensis infection alters the macrophage's outward currents and what the consequences of such changes might be. using the whole cell configuration of the patch clamp technique, we show th ...200818571651
efficacy of pentavalent antimony, amphotericin b, and miltefosine in leishmania amazonensis-infected macrophages under normoxic and hypoxic conditions.recently, our group demonstrated that mouse lesions infected with leishmania amazonensis are hypoxic. evidence indicates the negative impact of hypoxia on the efficacy of a variety of chemotherapeutic agents against tumors, fungi, bacteria, and malaria parasites. in the present study, comparison of the effect of antileishmanial drugs on l. amazonensis-infected macrophages under normoxic and hypoxic conditions was performed. we compared the effect of 5% oxygen tension with a tension of 21% oxygen ...200818576874
leishmania (leishmania) amazonensis: experimental cutaneous leishmaniasis associated with systemic amyloidosis in mice.we infected swiss and c57bl/6 female mice in the left hind footpad with 10(4)leishmania (l.) amazonensis promastigotes in stationary phase. the macroscopic examination showed a nodular non-ulcerated lesion at the site of inoculation and hepatic and spleenic enlargement. histopathologically, the primary lesion showed an extensive liquefactive necrosis and inflammatory infiltrate, mainly consisting of macrophages filled with amastigotes, and rare lymphocytes. the inflammatory reaction in liver, sp ...200818601926
synthesis and preliminary evaluation of new ursolic and oleanolic acids derivatives as antileishmanial agents.a series of new ursolic and oleanolic acids derivatives was synthesized via ursolic or oleanolic acids, previously extracted from south american ilex species. these new compounds were tested for in vitro antiparasitic activity on leishmania amazonensis and leishmania infantum strains. some of these compounds showed activity against the promastigote forms of l. amazonensis or l. infantum, with ic(50) ranging from 5 to 12 microm. as expected, most of the compounds showed a significant level of cyt ...200818608757
contrasting human cytokine responses to promastigote whole-cell extract and the leishmania analogue receptor for activated c kinase antigen of l. amazonensis in natural infection versus immunization.it is known that the same antigen can induce different immune responses, depending upon the way that it is presented to the immune system. the objective of this study was to compare cytokine responses of peripheral blood mononuclear cells (pbmc) from cutaneous leishmaniasis patients and subjects immunized with a first-generation candidate vaccine composed of killed leishmania amazonensis promastigotes to a whole-cell promastigote antigen extract (la) and to the recombinant protein lack (leishman ...200818627399
extracellular nucleotide metabolism in leishmania: influence of adenosine in the establishment of infection.leishmaniasis is a parasitic disease with a variety of clinical forms, which are related to the leishmania species involved. in the murine model, leishmania amazonensis causes chronic non-healing lesions in leishmania braziliensis- or leishmania major-resistant mouse strains. in this study, we investigated the involvement of the pathway of extracellular nucleotide hydrolysis, with special focus on the role of extracellular adenosine, in the establishment of leishmania infection. our results show ...200818656412
in vitro and in vivo activity of meglumine antimoniate produced at farmanguinhos-fiocruz, brazil, against leishmania (leishmania) amazonensis, l (l.) chagasi and l (viannia) braziliensis.the leishmanicidal activity of four batches of meglumine antimoniate, produced in farmanguinhos-fiocruz, brazil (tams), was assessed and compared to glucantime-aventis pharma ltda. using the amastigote-like in vitro model, the active concentrations of sb v varied from 10microg/ml to 300microg/ml for l. (l.) chagasi and from 50microg/ml to 300microg/ml for l. (l.) amazonensis, with no statistically significant differences among the four batches of tams and glucantime. the inhibitory concentration ...200818660990
two distinct arsenite-resistant variants of leishmania amazonensis take different routes to achieve resistance as revealed by comparative transcriptomics.genome-wide search for the genes involved in arsenite resistance in two distinct variants a and a' of leishmania amazonensis revealed that the two variants used two different mechanisms to achieve resistance, even though these two variants were derived from the same clone and selected against arsenite under the same conditions. in variant a, the variant with dna amplification, the biochemical pathways for detoxification of oxidative stress, the energy generation system to support the biochemical ...200818674569
antileishmanial activity of aldonamides and n-acyl-diamine derivatives.a number of lipophilic n-acyl-diamines and aldonamides have been synthesized and tested for their in vitro antiproliferative activity against leishmania amazonensis and l. chagasi. ribonamides, having one amino group, displayed good to moderate inhibition of parasite growth. the best result was obtained for compounds 10 and 15 with ic50 against l. chagasi below 5 microm.200818677429
epidemiology of cutaneous leishmaniasis in suriname: a study performed in 2006.cutaneous leishmaniasis (cl) is a widespread disease in suriname caused by leishmania viannia guyanensis. it is argued that other leishmania species are also responsible for cl and that the incidence is increasing. this study aimed to identify the species causing the disease and to estimate the annual detection rate of cl in suriname in 2006. in paramaribo, 152 patients were registered, of whom 33 were tested in two polymerase chain reaction (pcr)-restriction fragment length polymorphism (rflp) ...200818689623
the c-terminal extension of leishmania pifanoi amastigote-specific cysteine proteinase lpcys2: a putative function in macrophage infection.cysteine proteinases have been implicated in many aspects of protozoan parasite pathogenesis. these hydrolases are normally found as zymogens, and some classes in trypanosomatids possess a long c-terminal extension (cte), for which no function has been assigned. in this paper we hypothesize that the cte domain of lpcys2, the abundant lysosomal cysteine proteinase of leishmania pifanoi amastigotes, is involved in host cell infection. confirming previous reports that this peptide is highly immunog ...200818694784
leishmania amazonensis: characterization of an ouabain-insensitive na+-atpase activity.we characterized ouabain-insensitive na+-atpase activity present in the plasma membrane of leishmania amazonensis and investigated its possible role in the growth of the parasite. an increase in na+ concentration in the presence of 1mm ouabain, increased the atpase activity with a v(max) of 154.1+/-13.5nmol pi x h(-1) x mg(-1) and a k0.5 of 28.9+/-7.7mm. furosemide and sodium orthovanadate inhibited the na+-stimulated atpase activity with an ic(50) of 270microm and 0.10microm, respectively. furo ...200817825292
flagellar length depends on ldarl-3a gtp/gdp unaltered cycling in leishmania amazonensis.we have shown previously that expression of the gtp-blocked form of the small g protein ldarl-3a/q70l led to a marked shortening of leishmania promastigotes flagella. in contrast, there was no effect with the t30n mutant, thought to represent the gdp-blocked form. however, recent data, obtained with human arf-6, a member of the same family of g proteins, revealed that the corresponding mutant t27n was nucleotide-free and that the gdp-blocked form was the t44n mutant. when expressed in leishmania ...200817889949
effects of cxcl10 on dendritic cell and cd4+ t-cell functions during leishmania amazonensis infection.leishmania amazonensis can cause progressive disease in most inbred strains of mice. we have previously reported that treatment with cxcl10 activates macrophage (mphi) effector function(s) in parasite killing and significantly delays lesion development in susceptible c57bl/6 mice via enhanced gamma interferon (ifn-gamma) and interleukin 12 (il-12) secretion; however, the mechanism underlying this enhanced immunity against l. amazonensis infection remains largely unresolved. in this study, we uti ...200817998308
a leishmania (l.) amazonensis atp diphosphohydrolase isoform and potato apyrase share epitopes: antigenicity and correlation with disease progression.a leishmania (leishmania) amazonensis atp diphosphohydrolase isoform was partially purified from plasma membrane of promastigotes by preparative non-denaturing polyacrylamide gel electrophoresis. sds-page followed by western blots developed with polyclonal anti-potato apyrase antibodies identified diffuse bands of about 58-63 kda, possibly glycosylated forms of this protein. by elisa technique, a significantly higher total igg antibody level against potato apyrase was found in serum from promast ...200818005473
leishmania mexicana amazonensis: plasma membrane adenine nucleotide translocator and chemotaxis.leishmania cannot synthesize purines de novo and rely on their host to furnish these compounds. to accomplish this, they possess multiple purine nucleoside and nucleobase transporters. subcellular fractionation, immunohistochemical localization with anti-adenine nucleotide translocator (ant) antibodies and surface biotinylation show that the mitochondrial ant is also present in the plasma membrane of both promastigotes and amastigotes. leishmania, however, do not appear to rely on this transport ...200818031742
efficacy of the intralesional treatment with chenopodium ambrosioides in the murine infection by leishmania amazonensis.leishmaniasis, caused by protozoan from leishmania genus, is an endemic disease in the tropical and subtropical regions of the world. the chemotherapy to this disease is not always effective and can cause several side effects. chenopodium ambrosioides l. (chenopodiaceae) is used by the native people in the treatment of cutaneous ulcers caused by different species of leishmania. the aim of this study was to investigate the effect of the treatment with a hydroalcoholic crude extract (hce) from the ...200818035510
pathogenic role of b cells and antibodies in murine leishmania amazonensis infection.leishmania amazonensis infection, occurring predominantly in central and south america, can manifest itself in several forms, including those of cutaneous and diffuse cutaneous leishmaniasis. the outcome of l. amazonensis infection depends largely on host immune responses to the parasites. while cd4+ t cell activation is a prerequisite for pathogenesis in l. amazonensis-infected mice, the roles of b cells and their antibody production are unclear. in this study, we provide evidence suggesting th ...200817959178
trypanosomatid and fungal glycolipids and sphingolipids as infectivity factors and potential targets for development of new therapeutic strategies.several (glyco)(sphingo)lipids from different human pathogens have been characterized, and frequently many of these molecules are participating in host-pathogen interaction. in leishmania (leishmania) amazonensis, for example, amastigotes present on their surface glycosphingolipids (gsls) with the structure galbeta1-3galalpha, which is recognized by 30 kda receptor of macrophages. furthermore, other leishmania species, such as leishmania (leishmania) major and leishmania (viannia) braziliensis p ...200817976917
identification and enzymatic activities of four protein disulfide isomerase (pdi) isoforms of leishmania amazonensis.leishmania parasites primarily infect cells of macrophage lineage and can cause leishmaniasis in the skin, mucosal, and visceral organs, depending on both host- and parasite-derived factors. the protein disulfide isomerases (pdis) are thiol-disulfide oxidoreductases that catalyze the formation, reduction, and isomerization of disulfide bonds of proteins in cells. although four leishmania pdi genes are functionally inferred from homology in the genome sequences, only two of them have been express ...200818058133
a new antifungal and antiprotozoal depside from the andean lichen protousnea poeppigii.extracts from the andean lichens protousnea poeppigii and usnea florida displayed antimicrobial activity against the pathogenic fungi microsporum gypseum, trichophyton mentagrophytes and t. rubrum with mic values between 50 and 100 microg/ml. from the active extracts, four main metabolites were isolated and identified as the new depside, isodivaricatic acid, and the known metabolites 5-propylresorcinol, divaricatinic acid and usnic acid. isodivaricatic acid and divaricatinic acid presented antif ...200818058986
the putrescine analogue 1,4-diamino-2-butanone affects polyamine synthesis, transport, ultrastructure and intracellular survival in leishmania amazonensis.polyamines are important regulators of growth and differentiation in a variety of cells, including parasitic protozoa. promastigotes of leishmania species have high levels of putrescine and spermidine and their growth can be inhibited by polyamine biosynthesis antagonists. the putrescine analogue 1,4-diamino-2-butanone (dab) is microbicidal against tritrichomonas foetus and trypanosoma cruzi, so we tested its effects on leishmania amazonensis proliferation, viability, organization, putrescine tr ...200818832316
structure-activity relationship of (-) mammea a/bb derivatives against leishmania amazonensis.to study the structure-activity relationship of coumarin (-) mammea a/bb isolated from the ch(2)cl(2) extract of calophyllum brasiliense leaves, we evaluated the antileishmanial activity of natural, synthetic and derivatives of this coumarin, against promastigote and intracellular amastigote forms of leishmania amazonensis, and their cytotoxicity to j774g8 murine macrophages. the derivatives were obtained by hydrogenation and methoxylation reactions. the compound structures were elucidated on th ...200818849135
[comparative study between oral miltefosine and parenteral n-metil glucamine antimoniate for the treatment of experimental leishmaniasis caused leishmania (leishmania) amazonensis].twenty-five mice were infected with leishmania amazonensis and treated with glucamine and oral miltefosine. the criteria used were pad measurements and investigations of amastigotes and cultures after treatment. measurements: miltefosine 2.43 mm and glucamine 3.46 mm (p: 0.05). miltefosine smears and cultures were negative. glucamine produced two positive smears and the cultures were positive (p < 0.05). miltefosine was similar to or better than glucamine.200818853022
immunological characteristics of experimental murine infection with leishmania (leishmania) amazonensis.the murine models of leishmania infection are well-studied and suitable models for studying this disease, which, despite its incidence of nearly 2 million new cases worldwide per year and its prevalence of 12 million cases, has been a somewhat neglected disease. data obtained using such models are important for a better understanding of the disease in humans due to similarities in physiology and the advantage provided by the uniform infection profile within each mouse strain. in this review, we ...200818922635
control of parasitophorous vacuole expansion by lyst/beige restricts the intracellular growth of leishmania amazonensis.the intracellular protozoan leishmania replicates in parasitophorous vacuoles (pv) that share many features with late endosomes/lysosomes. l. amazonensis pvs expand markedly during infections, but the impact of pv size on parasite intracellular survival is still unknown. here we show that host cells infected with l. amazonensis upregulate transcription of lyst/beige, which was previously shown to regulate lysosome size. mutations in lyst/beige caused further pv expansion and enhanced l. amazonen ...200818927622
[sandfly fauna (diptera: psychodidae) in a focus of american cutaneous leishmaniasis on the urban periphery of manaus, state of amazonas].from august 2001 to july 2002, sand flies were collected from the bases of trees and, using cdc and disney traps, from areas surrounding homes and forested areas in the são joão community, on the urban periphery of manaus, state of amazonas. 4,104 specimens belonging to four subtribes, 13 genera and 49 species of the phlebotominae subfamily were collected. the subtribe psychodopygina predominated, with 3,403 (83%) specimens, especially of nyssomyia umbratilis, nyssomyia anduzei, trichophoromyia ...200819009191
[preliminary evaluation of maggot (diptera: calliphoridae) therapy as a potential treatment for leishmaniasis ulcers].maggot debridement therapy has been widely used for treating a variety of scarred-over soft-tissue wounds. published accounts record several illnesses in which treatment with larval therapy has promoted injury healing in conjunction with infection by bacterial pathogens resistant to conventional antibiotics.200818719732
in vitro sodium nitroprusside-mediated toxicity towards leishmania amazonensis promastigotes and axenic amastigotes.leishmania parasites survive despite exposure to the toxic nitrosative oxidants during phagocytosis by the host cell. in this work, the authors investigated comparatively the resistance of leishmania amazonensis promastigotes and axenic amastigotes to a relatively strong nitrosating agent that acts as a nitric oxide (no) donor, sodium nitroprusside (snp). results demonstrate that snp is able to decrease, in vitro, the number of l. amazonensis promastigotes and axenic amastigotes in a dose-depend ...200818720423
in vitro activities of er-119884 and e5700, two potent squalene synthase inhibitors, against leishmania amazonensis: antiproliferative, biochemical, and ultrastructural effects.er-119884 and e5700, novel arylquinuclidine derivatives developed as cholesterol-lowering agents, were potent in vitro growth inhibitors of both proliferative stages of leishmania amazonensis, the main causative agent of cutaneous leishmaniasis in south america, with the 50% inhibitory concentrations (ic(50)s) being in the low-nanomolar to subnanomolar range. the compounds were very potent noncompetitive inhibitors of native l. amazonensis squalene synthase (sqs), with inhibition constants also ...200818765694
effect of brazilian copaiba oils on leishmania amazonensis.copaiba oil has been used in folk medicine since the 19th century. the use of copaiba oils to treat leishmaniasis is cited in several ethnopharmacological studies. nevertheless, the potential antileishmania of copaiba oils had not been studied.200818775772
role of natural killer cells in modulating dendritic cell responses to leishmania amazonensis infection.the importance of the interaction between natural killer (nk) cells and dendritic cells (dcs) in the expansion of antiviral and antitumor immune responses is well-documented; however, limited information on dc-nk cell interaction during parasitic infections is available. given that some leishmania parasites are known to prevent or suppress dc activation, we developed a dc-nk cell coculture system to examine the role of nk cells in modulating the functions of leishmania-infected dcs. we found tha ...200818794295
in vivo activity of perifosine against leishmania amazonensis.miltefosine has been established as the first oral administration drug against cutaneous and visceral leishmaniasis. other alkyl-phospholipids such as edelfosine have been tested against leishmania showing an in vitro antiparasitic activity. perifosine in vitro activity has been previously demonstrated against different leishmania species including leishmania amazonensis. in this study edelfosine and perifosine were orally administered to balb/c mice at doses of 1 and 2.5 mg/kg/day during 28 day ...200818801328
divergence of trypanothione-dependent tryparedoxin cascade into cytosolic and mitochondrial pathways in arsenite-resistant variants of leishmania amazonensis.evidences are presented in the in vivo study that overexpression of tryparedoxin peroxidases (txnpxs) diverged into cytosolic pathway in arsenite-resistant variant a and mitochondrial pathway in variant a' of leishmania amazonensis is due to the upregulation of the corresponding upstream tryparedoxins (txns) in the cytosol as well as the mitochondrion respectively. evidences are also presented that exposure of l. amazonensis to arsenite in the early hours led to the production of reactive oxygen ...200818083246
n-acetyl-l: -cysteine reduces the parasitism of balb/c mice infected with leishmania amazonensis.leishmania amazonensis infection leads to progressive diseases in a majority of inbred strains of mice. glutathione (gsh) participates in a large number of cellular phenomena and seems to be essential for several immune functions, including host defense during leishmaniasis. in this study, we evaluated the effects of n-acetyl-l: -cysteine (nac), as gsh supplement, on the course of l. amazonensis infection in susceptible balb/c mice. the treatment with nac (200 mg/kg daily) was effective in raisi ...200818094999
leishmania amazonensis: biosynthesis of polyprenols of 9 isoprene units by amastigotes.the isoprenoid metabolic pathway in protozoa of the leishmania genus exhibits distinctive characteristics. these parasites, as well as other members of the trypanosomatidae family, synthesize ergosterol, instead of cholesterol, as the main membrane sterol lipid. leishmania has been shown to utilize leucine, instead of acetate as the main precursor for sterol biosynthesis. while mammalian dolichols are molecules containing 15-23 isoprene units, leishmania amazonensis promastigotes synthesize doli ...200818155196
leishmania spp.: delta-aminolevulinate-inducible neogenesis of porphyria by genetic complementation of incomplete heme biosynthesis pathway.to further develop the leishmania model for porphyria based on their deficiencies in heme biosynthesis, three old world species were doubly transfected as before for leishmania amazonensis with cdnas, encoding the 2nd and 3rd enzymes in the pathway. expression of the transgenes was verified immunologically at the protein level and functionally by uroporphyrin neogenesis that occurs only after exposure of the double-transfectants to delta-aminolevulinate. all species examined were equally deficie ...200818164705
iron acquisition within host cells and the pathogenicity of leishmania.iron is an essential cofactor for several enzymes and metabolic pathways, in both microbes and in their eukaryotic hosts. to avoid toxicity, iron acquisition is tightly regulated. this represents a particular challenge for pathogens that reside within the endocytic pathway of mammalian cells, because endosomes and lysosomes are gradually depleted in iron by host transporters. an important player in this process is nramp1 (slc11a1), a proton efflux pump that translocates fe(2+) and mn(2+) ions fr ...200818070118
increase in nuclear translocation of nuclear transcription factor-kappab following infection of a human schwann cell line with leishmania amazonensis. 200818070200
the effect of phospholipase a2 from crotalus durissus collilineatus on leishmania (leishmania) amazonensis infection.in this study, the effect of phospholipase a2 (pla2) derived from crotalus durissus collilineatus was evaluated in vitro and in vivo on experimental cutaneous leishmaniasis. the promastigote and amastigote forms treated with pla2 presented increased growth rate. in vivo studies showed that pla2-treated leishmania (leishmania) amazonensis promastigotes increased the size of lesions in balb/c mice, and histopathological analysis showed numerous necrotic regions presenting a higher density of polym ...200818180953
anti-leishmanial and structure-activity relationship of ring substituted 3-phenyl-1-(1,4-di-n-oxide quinoxalin-2-yl)-2-propen-1-one derivatives.a series of ring substituted 3-phenyl-1-(1,4-di-n-oxide quinoxalin-2-yl)-2-propen-1-one derivatives were synthesized and tested for in vitro leishmanicidal activity against amastigotes of leishmania amazonensis in axenical cultures and murine infected macrophages. structure-activity relationships demonstrated the importance of a radical methoxy at position r3', r4' and r5'. (2e)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-1,4-dioxy-quinoxalin-2-yl)-propenone was the most active. cytotoxicity ...200819148416
leishmanicidal metabolites from cochliobolus sp., an endophytic fungus isolated from piptadenia adiantoides (fabaceae).protozoan parasites belonging to genera leishmania and trypanosoma are the etiological agents of severe neglected tropical diseases (ntds) that cause enormous social and economic impact in many countries of tropical and sub-tropical areas of the world. in our screening program for new drug leads from natural sources, we found that the crude extract of the endophytic fungus cochliobolus sp. (ufmgcb-555) could kill 90% of the amastigote-like forms of leishmania amazonensis and inhibit by 100% ellm ...200819079599
active transport of glutamate in leishmania (leishmania) amazonensis.leishmania spp. are the causative agents of leishmaniasis, a complex of diseases with a broad spectrum of clinical manifestations. leishmania (leishmania) amazonensis is a main etiological agent of diffuse cutaneous leishmaniasis. leishmania spp., as other trypanosomatids, possess a metabolism based significantly on the consumption of amino acids. however, the transport of amino acids in these organisms remains poorly understood with few exceptions. glutamate transport is an important biological ...200819017058
the activity of azithromycin against leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis in the golden hamster model.new therapeutic alternatives against leishmaniasis remain a priority. the activity of azithromycin against leishmania (leishmania) major has been previously demonstrated. different responses among species of leishmania make species-specific drug screening necessary. the activity of azithromycin against leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis was evaluated in golden hamsters infected through footpad injections of metacyclic promastigotes, and compared with untrea ...200718200413
oligopeptidase b from leishmania amazonensis: molecular cloning, gene expression analysis and molecular model.serine oligopeptidases of trypanosomatids are emerging as important virulence factors and therapeutic targets in trypanosome infections. a complete open reading frame of oligopeptidase b from leishmania amazonensis was amplified with polymerase chain reaction with gradient annealing temperatures using primers designed for the oligopeptidase b gene from l. major. the 2,196-bp fragment coded for a protein of 731 amino acids with a predicted molecular mass of 83.49 kda. the encoded protein (la_opb) ...200718074461
protective effect of lectin from synadenium carinatum on leishmania amazonensis infection in balb/c mice.the protective effect of the synadenium carinatum latex lectin (scll), and the possibility of using it as an adjuvant in murine model of vaccination against american cutaneous leishmaniasis, were evaluated. balb/c mice were immunized with the lectin scll (10, 50, 100 microgram/animal) separately or in association with the soluble leishmania amazonensis antigen (sla). after a challenge infection with 10(6) promastigotes, the injury progression was monitored weekly by measuring the footpad swellin ...200718165707
rna polymerase i promoter and splice acceptor site recognition affect gene expression in non-pathogenic leishmania species.leishmania (sauroleishmania) tarentolae has biotechnological potential for use as live vaccine against visceral leishmaniasis and as a system for the over expression of eukaryotic proteins that possess accurate post-translational modifications. for both purposes, new systems for protein expression in this non-pathogenic protozoan are necessary. the ribosomal rna promoter proved to be a stronger transcription driver since its use yielded increased levels of recombinant protein in organisms of bot ...200718060313
expression of hypoxia-inducible factor 1alpha in mononuclear phagocytes infected with leishmania amazonensis.increasing evidence indicates that hypoxia-inducible factor 1alpha (hif-1alpha) can be upregulated in different cell types by nonhypoxic stimuli such as growth factors, cytokines, nitric oxide, lipopolysaccharides and a range of infectious microorganisms. in this study, the ability of the following mononuclear phagocytes to express hif-1alpha is reported: mouse macrophages (mmphi), human macrophages (hmphi) and human dendritic cells (dc), parasitized in vitro with leishmania amazonensis; as asse ...200717983667
synthesis of new 4-(e)-alkenylpyrrolo[1,2-a]quinoxalines as antileishmanial agents by suzuki-miyaura cross-coupling reactions.a series of new 4-(e)-alkenylpyrrolo[1,2-a]quinoxaline derivatives, structural analogues of alkaloid chimanine b, was synthesized in good yields using efficient palladium(0)-catalyzed suzuki-miyaura cross-coupling reactions. these new compounds were tested for in vitro antiparasitic activity upon leishmania amazonensis and leishmania infantum strains. biological results showed activity against the promastigote forms of l. amazonensis and l. infantum with ic50 ranging from 0.5 to 7 microm. from a ...200718035821
leishmania dna is rapidly degraded following parasite death: an analysis by microscopy and real-time pcr.control of human leishmaniases relies on appropriate diagnosis and reliable methods for monitoring chemotherapy. the current method used for estimation of parasite burden during chemotherapy patient follow-up as well as in pharmacological studies performed in experimental models involves pcr-based assays. compared to time-consuming conventional methods, this type of leishmania dna detection-based method is extremely sensitive, but could fail in distinguishing viable leishmania from slowly degene ...200717890124
leishmania amazonensis infection impairs differentiation and function of human dendritic cells.dendritic cells (dcs) are of utmost importance in initiating an immune response and may also function as targets for pathogens. the presence of pathogens inside dcs is likely to impair their functions and thus, influence immune responses. in the present report, we evaluated the impact of the presence of leishmania amazonensis during differentiation and maturation of human monocyte-derived dcs. the presence of live l. amazonensis parasites during dc differentiation led to a significant decrease i ...200717890507
analysis and chromosomal mapping of leishmania (leishmania) amazonensis amastigote expressed sequence tags.the characterization of expressed sequence tags (ests) generated from a cdna library of leishmania (leishmania) amazonensis amastigotes is described. the sequencing of 93 clones generated new l. (l.) amazonensis ests from which 32% are not related to any other sequences in database and 68% presented significant similarities to known genes. the chromosome localization of some l. (l.) amazonensis ests was also determined in l. (l.) amazonensis and l. (l.) major. the characterization of these ests ...200717923999
unveiling pathways used by leishmania amazonensis amastigotes to subvert macrophage function.this article provides a summary and discussion of properties of leishmania amazonensis-loaded mouse macrophages. it illustrates how high-throughput analysis is expected to contribute to deciphering features displayed by macrophages when they are subverted as host cells for replicating leishmania amastigotes. firstly, we discuss features of mouse mononuclear phagocytes in steady-state conditions, including the phagocytosis of apoptotic cells. secondly, we discuss results from ongoing investigatio ...200717850482
structure-activity relationship of antileishmanials neolignan analogues.twenty-two synthetic analogues of neolignans comprising beta-ketoethers and beta-ketosulfides were obtained from condensation reactions among beta-bromoketones and phenols or thiophenols, respectively, in basic solutions, and assayed in vitro for activity against intracellular leishmania amazonensis and leishmania donovani amastigotes, the causative agents of cutaneous and visceral leishmaniasis. the highest selective activity was found for compounds with sulfur bridges, whereas beta-ketosulphox ...200717888668
evaluation of the leishmanicidal activity of plants used by peruvian chayahuita ethnic group.a total of 27 ethanolic plant extracts from 27 species were screened for leishmanicidal activity in vitro against leishmania amazonensis. most of the selected species (19) are traditionally used by the chayahuitas, an amazonian peruvian ethnic group, to treat skin affections and/or leishmaniasis.200717889471
synthesis and in vitro evaluation of leishmanicidal and trypanocidal activities of n-quinolin-8-yl-arylsulfonamides.in the present paper 12 n-quinolin-8-yl-arylsulfonamides synthesized by coupling 8-aminoquinolines with various arylsulfonylchlorides were assayed in vitro against leishmania amazonensis, leishmania chagasi and trypanosoma cruzi strains. this series of new compounds were found to be selective for leishmania spp. promastigote and amastigote forms. the most active compound was the n-(8-quinolyl)-3,5-difluoro-benzenesulfonamide 10 with an ic(50) against l. amazonensis and l. chagasi of 2.12 and 0.4 ...200717889546
a comparative study of mesoionic compounds in leishmania sp. and toxicity evaluation.in this first study, a series of mesoionic compounds like 1,3,4-thiadiazolium-2-phenylamine derivatives were synthesized and studied in leishmania amazonensis. the cytotoxic effects of these compounds on the host cells were investigated and the antileishmanial in vitro activity was compared with other species of leishmania (leishmania chagasi and leishmania braziliensis). the compounds presented lower toxicity in murine macrophages than the reference drug pentamidine. the halogen derivatives 5, ...200717367894
first report of diffuse cutaneous leishmaniasis and leishmania amazonensis infection in rio de janeiro state, brazil.diffuse cutaneous leishmaniasis (dcl) is characterised by multiple and progressive cutaneous lesions, resistance to chemotherapy and leishmania-specific t-cell anergy. we report the first autochthonous dcl case and the first human infection with leishmania amazonensis in rio de janeiro state, brazil, where only l. braziliensis is considered to be the causative agent of cutaneous leishmaniasis. leishmania amazonensis was identified by multilocus enzyme electrophoresis and pcr-rflp. our case was d ...200717368698
leishmania amazonensis trypanothione reductase: evaluation of the effect of glutathione analogs on parasite growth, infectivity and enzyme activity.trypanothione reductase (tr) is a major enzyme in trypanosomatids. its substrate, trypanothione is a molecule containing a tripeptide (l-glutamic acid-cysteine-glycine) coupled to a polyamine, spermidine. this redox system (tr/trypanothione) is vital for parasite survival within the host cell and has been described as a good target for chemotherapy anti-leishmania. the use of tripeptides analogs of glutathione would result in a decrease in trypanothione synthesis and as a consequence in tr activ ...200717373550
l-arginine and cationic amino acid transporter 2b regulate growth and survival of leishmania amazonensis amastigotes in macrophages.leishmania spp. are obligate intracellular parasites, requiring a suitable microenvironment for their growth within host cells. we previously reported that the growth of leishmania amazonensis amastigotes in murine macrophages (mphis) was enhanced in the presence of gamma interferon (ifn-gamma), a th1 cytokine normally associated with classical mphi activation and killing of intracellular pathogens. in this study, we provided several lines of evidence suggesting that ifn-gamma-mediated parasite ...200717387163
anti-leishmania activity of semi-purified fraction of jacaranda puberula leaves.the crude methanolic extract from leaves of jacaranda puberula showed activity against leishmania (leishmania) amazonensis. the extract presented active against promastigote forms with an inhibitory concentration 50% (ic(50)) value of 88.0 mug/ml, but only moderated activity against amastigote forms; however in higher concentrations the extract showed cytotoxic effects. the bio-guided chromatographic fractionation the crude methanolic extract against amastigotes yielded a fraction with an ic(50) ...200717390147
macrophage killing of leishmania amazonensis amastigotes requires both nitric oxide and superoxide.the requirements for effective and efficient intracellular killing of leishmania amazonensis by activated macrophages are unknown. despite resistance to the arginase inhibitor loha by intracellular l. amazonensis amastigotes, enhanced replication did not account for the relative resistance of this parasite to macrophage activation. herein we report that the presence of both superoxide and nitric oxide is necessary for efficient killing of l. amazonensis amastigotes within lps/ifn-gamma-activated ...200717426168
effects of brazilian propolis on leishmania amazonensis.leishmaniasis, an endemic parasitosis that leads to chronic cutaneous, mucocutaneous or visceral lesions, is part of those diseases, which still requires improved control tools. propolis has shown activities against different bacteria, fungi, and parasites. in this study we investigated the effect of four ethanolic extracts of typified propolis collected in different brazilian states, on leishmania amazonensis performing assays with promastigote forms, extracellular amastigotes, and on infected ...200717426888
a trial of immunotherapy against leishmania amazonensis infection in vitro and in vivo with z-100, a polysaccharide obtained from mycobacterium tuberculosis, alone or combined with meglumine antimoniate.to determine the efficacy and the immunomodulatory function of z-100 alone or combined with meglumine antimoniate on leishmania amazonensis infection.200717439977
synthesis and evaluation of new difluoromethyl azoles as antileishmanial agents.several compounds of great pharmacological interest contain the triazole and imidazole rings. in order to find new drugs with antileishmanial activity we have synthesized and evaluated new imidazole and triazole compounds carrying either the carbaldehyde or the difluoromethylene functionalities against promastigote forms of leishmania amazonensis. among the compounds tested difluoromethylene azoles 4b and 8f have inhibited the parasite growth significantly. our results show that the introduction ...200717445951
oral leishmaniasis: a clinicopathological study of 11 cases.leishmaniasis is a parasitic disease with diverse clinical manifestations, and considered a public health problem in endemic countries such as brazil. mucosal lesions usually involve the upper respiratory tract, with a predilection for nose and larynx. oral involvement is unusual and in most cases it becomes evident after several years of resolution of the original cutaneous lesions. oral lesions classically appear as mucosal ulcerations, mainly in the hard or soft palate. this report describes ...200717448219
spirolactone iridoids might be responsible for the antileishmanial activity of a peruvian traditional remedy made with himatanthus sucuuba (apocynaceae).extracts of seven medicinal plants used specifically against cutaneous leishmaniasis in the madre de dios region of peru were evaluated in vitro against promastigote and axenic amastigote forms of leishmania amazonensis. one of them showed interesting leishmanicidal activities (ic(50)=5 microg/ml in amastigotes). bio-guided isolation of the stem bark's ethanol extract of himatanthus sucuuba (spruce ex müll. arg.) woodson (apocynaceae) afforded the spirolactone iridoids isoplumericin and plumeric ...200717459622
leishmania amazonensis: pkc-like protein kinase modulates the (na++k+)atpase activity.the present study aimed to identify the presence of protein kinase c-like (pkc-like) in leishmania amazonensis and to elucidate its possible role in the modulation of the (na(+)+k(+))atpase activity. immunoblotting experiments using antibody against a consensus sequence (ac 543-549) of rabbit protein kinase c (pkc) revealed the presence of a protein kinase of 80 kda in l. amazonensis. measurements of protein kinase activity showed the presence of both (ca(2+)-dependent) and (ca(2+)-independent) ...200717475255
antileishmanial activity of crude extract and coumarin from calophyllum brasiliense leaves against leishmania amazonensis.infections by protozoans of the genus leishmania are a major worldwide health problem, with high endemicity in developing countries. the drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which show renal and cardiac toxicity. as part of a search for new drugs against leishmaniasis, we evaluated the in vitro leishmanicidal activity of the (-) mammea a/bb. the compound (-) mammea a/bb is a coumarin-type mammea purified from a dichloromethane crude extract of leave ...200717483964
leishmania replication protein a-1 binds in vivo single-stranded telomeric dna.replication protein a (rpa) is a highly conserved heterotrimeric single-stranded dna-binding protein involved in different events of dna metabolism. in yeast, subunits 1 (rpa-1) and 2 (rpa-2) work also as telomerase recruiters and, in humans, the complex unfolds g-quartet structures formed by the 3' g-rich telomeric strand. in most eukaryotes, rpa-1 and rpa-2 bind dna using multiple ob fold domains. in trypanosomatids, including leishmania, rpa-1 has a canonical ob fold and a truncated rfa-1 str ...200717498665
larbp38: a leishmania amazonensis protein that binds nuclear and kinetoplast dnas.leishmania amazonensis causes a wide spectrum of leishmaniasis. there are no vaccines or adequate treatment for leishmaniasis, therefore there is considerable interest in the identification of new targets for anti-leishmania drugs. the central role of telomere-binding proteins in cell maintenance makes these proteins potential targets for new drugs. in this work, we used a combination of purification chromatographies to screen l. amazonensis proteins for molecules capable of binding double-stran ...200717506988
oligopeptidase b from l. amazonensis: molecular cloning, gene expression analysis and molecular model.serine oligopeptidases of trypanosomatids are emerging as important virulence factors and therapeutic targets in trypanosome infections. a complete open reading frame of oligopeptidase b from leishmania amazonensis was amplified with polymerase chain reaction with gradient annealing temperatures using primers designed for the oligopeptidase b gene from l. major. the 2,196-bp fragment coded for a protein of 731 amino acids with a predicted molecular mass of 83.49 kda. the encoded protein (la_opb) ...200717530480
role of leishmania (leishmania) amazonensis amastigote glycosphingolipids in macrophage infectivity.the role of glycosphingolipids (gsls) present in amastigote forms of leishmania (leishmania) amazonensis during infection of macrophages was analyzed, with particular emphasis on gsls presenting the terminal galpss1-3galpa disaccharide. macrophage invasion by l. (l.) amazonensis amastigotes was reduced by 37% when the disaccharide galpss1-3galp (1 mm) was added to the culture medium. the putative macrophage receptor/lectin for ss-gal-globotriaosylceramide (galpss1-3galpa1-4galpss1-4glc pss1-1cer ...200717581678
tamoxifen is effective against leishmania and induces a rapid alkalinization of parasitophorous vacuoles harbouring leishmania (leishmania) amazonensis amastigotes.this study was performed to investigate the activity of tamoxifen, an antioestrogen widely used in the treatment of breast cancer, against leishmania.200717584801
genetic diversity of leishmania amazonensis strains isolated in northeastern brazil as revealed by dna sequencing, pcr-based analyses and molecular karyotyping.leishmania (leishmania) amazonensis infection in man results in a clinical spectrum of disease manifestations ranging from cutaneous to mucosal or visceral involvement. in the present study, we have investigated the genetic variability of 18 l. amazonensis strains isolated in northeastern brazil from patients with different clinical manifestations of leishmaniasis. parasite dna was analyzed by sequencing of the its flanking the 5.8 s subunit of the ribosomal rna genes, by rapd and ssr-pcr and by ...200717584940
effect of insulin-like growth factor-i on leishmania amazonensis promastigote arginase activation and reciprocal inhibition of nos2 pathway in macrophage in vitro.we showed previously that insulin-like growth factor (igf)-i induces an exacerbation of the lesion development in experimental cutaneous leishmaniasis favouring parasite growth within host macrophages. here we studied the effect of igf-i in vitro in balb/c mouse peritoneal macrophages infected with stationary phase leishmania amazonensis promastigotes. igf-i was used to pre-incubate either macrophage or parasite before infection of the macrophages or adding it at the start of the leishmania-macr ...200717635806
evaluation of immune responses and protection induced by a2 and nucleoside hydrolase (nh) dna vaccines against leishmania chagasi and leishmania amazonensis experimental infections.several antigens have been tested as vaccine candidates against leishmania infections but controversial results have been reported when different antigens are co-administered in combined vaccination protocols. immunization with a2 or nucleoside hydrolase (nh) antigens was previously shown to induce th1 immune responses and protection in balb/c mice against leishmania donovani and l. amazonensis (a2) or l. donovani and l. mexicana (nh) infections. in this work, we investigated the protective effi ...200717644455
anti-leishmanial and immunomodulatory activities of extracts from portulaca hirsutissima and portulaca werdermannii.ethyl acetate and chloroform extracts from aerial parts of portulaca werdermannii and p. hirsutissima were tested in lymphoproliferation assays and axenic cultures of leishmania amazonensis and trypanosoma cruzi. both extracts of p. werdermannii and p. hirsutissima had a potent inhibitory activity on lymphocyte proliferation. on the contrary, only the chloroformic extract of both plants inhibited l. amazonensis growth, without effect on t. cruzi cultures. these results indicate these portulaca s ...200717651913
leishmania (leishmania) amazonensis infection and dissemination in mice inoculated with stationary-phase or with purified metacyclic promastigotes.leishmania (leishmania) amazonensis is a protozoan of the american continent that causes localized cutaneous leishmaniasis and, rarely, the diffuse cutaneous form of disease in humans. it has become clear in recent years that the course of leishmania major infection in the mouse model differs when low numbers of purified metacyclic forms are used as inocula in comparison with the traditionally hitherto studied infection models that used large numbers of stationary-phase (sp) promastigotes. the l ...200717655808
comparative studies of the anti-leishmanial activity of three crotalus durissus ssp. venoms.in this study, we compared the anti-leishmanial activity of three crotalic venoms (crotalus durissus terrificus-cdt, crotalus durissus cascavella-cdca, and crotalus durissus collilineatus-cdcol). different concentrations of each venom incubated with leishmania (leishmania) amazonensis promastigotes were used. cdt venom exhibited a higher anti-leishmanial activity (inhibitory concentration-ic50-value of 4.70+/-1.72 microg/ml) in comparison with that of cdca venom (ic50 value of 9.41+/-1.21 microg ...200717659386
cd8+ t cells are not required for vaccine-induced immunity against leishmania amazonensis in il-12/23p40(-/-) c57bl/6 mice.vaccine-induced protection against leishmaniasis is largely dependent on cell-mediated type 1 response and il-12-driven ifn-gamma production. surprisingly, our previous data showed that il-12/23p40(-/-) mice could be vaccinated against l. amazonensis and were able to produce limited amounts of ifn-gamma. since the role of cd8+ t in immunization against l. amazonensis is obscure, the aim of this study was to evaluate the effects of cd8+ cells in protection against l. amazonensis in il-12/23p40(-/ ...200717662634
latbp1: a leishmania amazonensis dna-binding protein that associates in vivo with telomeres and gt-rich dna using a myb-like domain.different species of leishmania can cause a variety of medically important diseases, whose control and treatment are still health problems. telomere binding proteins (tbps) have potential as targets for anti-parasitic chemotherapy because of their importance for genome stability and cell viability. here, we describe latbp1 a protein that has a myb-like dna-binding domain, a feature shared by most double-stranded telomeric proteins. binding assays using full-length and truncated latbp1 combined w ...200717678615
role of interleukin-1beta in activating the cd11c(high) cd45rb- dendritic cell subset and priming leishmania amazonensis-specific cd4+ t cells in vitro and in vivo.cutaneous leishmaniasis associated with leishmania amazonensis infection is characterized by uncontrolled parasite replication and profound immunosuppression; however, the underlying mechanisms remain largely unclear. one possibility is that the l. amazonensis parasite modulates antigen-presenting cells, favoring the generation of pathogenic th cells that are capable of recruiting leukocytes but insufficient to fully activate their microbicidal activities. to test this possibility, we infected b ...200717682041
experimental leishmania (l.) amazonensis leishmaniasis: characterization and immunogenicity of subcellular fractions.a technique developed in trypanosoma cruzi biochemical studies was successfully used to fractionate leishmania (leishmania) amazonensis promastigotes. ultrastructural analyses revealed a membrane fraction (mf) associated to subpellicular microtubules, a ribosomal-rich microsomal fraction (micf), and a flagellar fraction (ff) free of associated membrane. all fractions proved to be immunogenic through delayed type hypersensitivity reaction assays. therefore, a protocol was designed to test whether ...200717691027
crude ethanolic extract, lignoid fraction and yangambin from ocotea duckei (lauraceae) show antileishmanial activity.crude ethanolic extract, lignoid fraction and the purified compound yangambin were obtained from ocotea duckei (lauraceae) and their antileishmanial activity was tested against promastigote forms of leishmania chagasi and leishmania amazonensis cultivated in schneider medium, supplemented with 20% of fetal bovine serum. all substances presented antileishmanial activity with ic50 values of 135.7 microg/ml for the crude ethanolic extract, 26.5 microg/ml for the lignoid fraction and 49.0 microg/ml ...200717708438
sterol methenyl transferase inhibitors alter the ultrastructure and function of the leishmania amazonensis mitochondrion leading to potent growth inhibition.we describe here the effects of delta(24(25)) sterol methenyl transferase inhibitors (smti) on promastigote and axenic amastigote forms of leishmania amazonensis. when these cells were exposed to 20-piperidin-2-yl-5alpha-pregnan-3beta-20-diol (22,26-azasterol; aza), hydrazone-imidazol-2-yl-5alpha-pregnan-3beta-ol (imi), 20-hydrazone-pyridin-2-yl-5alpha-pregnan-3beta-ol (pyr) or 24(r,s),25-epiiminolanosterol (eil), a concentration- and time-dependent inhibition of growth was observed, with ic(50) ...200717719843
the first records of leishmania (leishmania) amazonensis in dogs (canis familiaris) diagnosed clinically as having canine visceral leishmaniasis from araçatuba county, são paulo state, brazil.two cases of leishmania (leishmania) amazonensis are reported in the domestic dog (canis familiaris). these are the first records of this parasite in this species. the animals lived in the endemic visceral leishmaniasis area of araçatuba, são paulo state, brazil and were initially diagnosed, on clinical grounds, as having visceral leishmaniasis. attempted parasite isolation from inguinal lymph node aspirates was unsuccessful and the indirect immunofluorescent test for visceral leishmaniasis was ...200717720321
effects of serine protease inhibitors on viability and morphology of leishmania (leishmania) amazonensis promastigotes.to investigate the importance of serine proteases in leishmania amazonensis promastigotes, we analyzed the effects of classical serine protease inhibitors and a kunitz-type inhibitor, obtained from sea anemone stichodactyla helianthus (shpi-i), on the viability and morphology of parasites in culture. classical inhibitors were selected on the basis of their ability to inhibit l. amazonensis serine proteases, previously described. the n-tosyl-l: -phenylalanine chloromethyl ketone (tpck) and benzam ...200717726617
combined effect of the essential oil from chenopodium ambrosioides and antileishmanial drugs on promastigotes of leishmania amazonensis.to date, there are no vaccines against leishmania, and chemotherapy remains the mainstay for the control of leishmaniasis. the drugs of choice used for leishmaniasis therapy are significantly toxic, expensive and with a growing frequency of refractory infections. because of these limitations, a combination therapy is the better hope. this work demonstrates that the essential oil from chenopodium ambrosioides shows a synergic activity after incubation in conjunction with pentamidine against proma ...200717823757
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