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hypoxia modulates phenotype, inflammatory response, and leishmanial infection of human dendritic cells.development of hypoxic areas occurs during infectious and inflammatory processes and dendritic cells (dcs) are involved in both innate and adaptive immunity in diseased tissues. our group previously reported that macrophages exposed to hypoxia were infected with the intracellular parasite leishmania amazonensis, but showed reduced susceptibility to the parasite. this study shows that although hypoxia did not alter human dc viability, it significantly altered phenotypic and functional characteris ...201020132174
apoptosis and apoptotic mimicry: the leishmania connection.different death-styles have been described in unicellular organisms. in most cases they evolve with phenotypic features similar to apoptotic death of animal cells, such as phosphatidylserine (ps) exposure, oligonucleosomal dna fragmentation, and loss of mitochondrial transmembrane potential, hinting that similar mechanisms operate in both situations. however, the biochemical pathways underlying death in unicellular organisms are still unclear. host recognition of ps exposed on the surface of uni ...201020140747
iron metabolism in trypanosomatids, and its crucial role in infection.iron is almost ubiquitous in living organisms due to the utility of its redox chemistry. it is also dangerous as it can catalyse the formation of reactive free radicals - a classical double-edged sword. in this review, we examine the uptake and usage of iron by trypanosomatids and discuss how modulation of host iron metabolism plays an important role in the protective response. trypanosomatids require iron for crucial processes including dna replication, antioxidant defence, mitochondrial respir ...201020152063
a new experimental culture medium for cultivation of leishmania amazonensis: its efficacy for the continuous in vitro growth and differentiation of infective promastigote forms.parasites from the genus leishmania cause a variety of disease states in humans and other mammals in tropical and subtropical regions, which include cutaneous, mucocutaneous and visceral leishmaniasis. the elaboration of a culture medium for the in vitro cultivation of leishmania spp., which promotes the growth and differentiation of the parasites, is an important tool for diagnosis, biochemical, biological and immunological studies in the genus. herein, we have reported the development of a rap ...201020177905
comparative evaluation of phenol and thimerosal as preservatives for a candidate vaccine against american cutaneous leishmaniasis.for decades thimerosal has been used as a preservative in the candidate vaccine for cutaneous leishmaniasis, which was developed by mayrink et al. the use of thimerosal in humans has been banned due to its mercury content. this study addresses the standardization of phenol as a new candidate vaccine preservative. we have found that the proteolytic activity was abolished when the test was conducted using the candidate vaccine added to merthiolate (mtvac) as well as to phenol (phvac). the monteneg ...201020209335
an enhanced method for the identification of leishmania spp. using real-time polymerase chain reaction and sequence analysis of the 7sl rna gene region.the accurate identification of leishmania spp. is important for the treatment of infected patients. molecular methods offer an alternative to time-consuming traditional laboratory techniques for species determination. we redesigned a 7sl rna gene-based polymerase chain reaction and sequence assay for increased species identification. dna extracted from 17 reference strains and 10 cultured clinical isolates was examined. sequence comparison was used successfully to identify organisms to the compl ...201020226334
trypanocidal, leishmanicidal and antifungal potential from marine red alga bostrychia tenella j. agardh (rhodomelaceae, ceramiales).specimens of the red alga bostrychia tenella j. agardh (rhodomelaceae, ceramiales) were collected from the são paulo coast and submitted to room temperature solvent extraction. the resulting extract was fractionated by partitioning with organic solvent. the n-hexane (bt-h) and dichloromethane (bt-d) fractions showed antiprotozoal potential in biological tests with trypanosoma cruzi and leishmania amazonensis and presented high activity in an antifungal assay with the phytopathogenic fungi clados ...201020236785
leishmania (leishmania) amazonensis infection in mice treated with fty720.in transplantation, parasite diseases are transmitted from the donor, or appear as de novo infections, or activate from a dormant insource as a consequence of immunosuppression. clinical findings have shown that an intact immune system is crucial to prevent recurrence of leishmania infection. we used balb/c and c57bl/6 mice to evaluate the role of fty720 in leishmaniasis. mice inoculated with leishmania (leishmania) amazonensis were followed over 7 weeks for foot thickness measurements after ini ...201020304196
[phlebotomine fauna (diptera: psychodidae) in a campina reserve in the state of amazonas, and its epidemiological importance].in brazil, the largest diversity of phlebotomines is found in the amazon region, particularly in undisturbed terra-firma forest. however, the phlebotomine fauna in other ecosystems of this region is still not well known.201020305974
trypanoside, anti-tuberculosis, leishmanicidal, and cytotoxic activities of tetrahydrobenzothienopyrimidines.the synthesis of 2-(5,6,7,8-tetrahydro[1]benzothieno[2,3-d]pyrimidin-4-yl)hydrazone-derivatives (btps) and their in vitro evaluation against trypanosoma cruzi trypomastigotes, mycobacterium tuberculosis, leishmania amazonensis axenic amastigotes, and six human cancer cell lines is described. the in vivo activity of the most active and least toxic compounds against t. cruzi and l. amazonensis was also studied. btps constitute a new family of drug leads with potential activity against infectious d ...201020356752
novel arylimidamides for treatment of visceral leishmaniasis.arylimidamides (aias) represent a new class of molecules that exhibit potent antileishmanial activity (50% inhibitory concentration [ic(50)], <1 microm) against both leishmania donovani axenic amastigotes and intracellular leishmania, the causative agent for human visceral leishmaniasis (vl). a systematic lead discovery program was employed to characterize in vitro and in vivo antileishmanial activities, pharmacokinetics, mutagenicities, and toxicities of two novel aias, db745 and db766. they we ...201020368397
selection and phenotype characterization of potassium antimony tartrate-resistant populations of four new world leishmania species.in the present study, we selected in vitro populations of leishmania viannia guyanensis, l.v. braziliensis, l. leishmania amazonensis and l.l. infantum chagasi that were resistant to potassium antimony tartrate (sbiii). the resistance index of these populations varied from 4- to 20-fold higher than that of their wild-type counterparts. to evaluate the stability of the resistance phenotype, these four resistant populations were passaged 37 to 47 times in a culture medium without sbiii. no change ...201020372925
antitrypanosomal and antileishmanial activities of novel n-alkyl-(1-phenylsubstituted-beta-carboline)-3-carboxamides.a series of 1-phenylsubstituted beta-carbolines containing an n-butylcarboxamide group at c-3 of beta-carboline nucleus were synthesized and evaluated in vitro against epimastigote form of trypanosoma cruzi and promastigote form of leishmania amazonensis. among all compounds tested, two derivatives (2b and 2d) presented potent activity against both parasites. the most active derivative 2b showed also the higher selectivity index ratio (si) for l. amazonensis (si=2,084). the effect of other n-alk ...201020382497
the influence of ecto-nucleotidases on leishmania amazonensis infection and immune response in c57b/6 mice.previous results from our laboratory and from the literature have implicated the expression of ecto-nucleotidases in the establishment of leishmania infection. in the present study we evaluated the correlation between ecto-nucleotidasic activity and the infectivity of l. amazonensis promastigotes that were kept in culture for short or extended numbers of passages, a condition that is known to decrease parasite infectivity. we also analyzed the immune response associated with the infection by the ...201020399737
the leishmania amazonensis trf (ttaggg repeat-binding factor) homologue binds and co-localizes with telomeres.telomeres are specialized structures at the end of chromosomes essential for maintaining genome stability and cell viability. the importance of telomeric proteins for telomere maintenance has increased our interest in the identification of homologues within the genus leishmania. the mammalian trf1 and trf2 proteins, for example, bind double-stranded telomeres via a myb-like dna-binding domain and are involved with telomere length regulation and chromosome end protection. in addition, trf2 can mo ...201020459667
immunopathological studies of leishmania amazonensis infection in resistant and in susceptible mice.leishmania amazonensis infection was studied in mice to evaluate the evolution of leishmaniasis. the association of different methods, such as lesion kinetics, limiting dilution analysis, and immunohistochemistry, established different levels of susceptibility and resistance. mice were arranged in 3 groups: susceptible (c57bl/10 and cba), relatively resistant (dba/2), and resistant (c3h.he). the histopathological analysis of primary lesions and draining lymph nodes showed a predominance of eosin ...201020462353
leishmanicidal activity of echinaster (othilia) echinophorus crude extract.in this study, a methanolic extract from echinaster (othilia) echinophorus was evaluated for activity against leishmania amazonensis. the extract showed activity against the promastigote and amastigote forms with ic50 values of 62.9 and 37.5 microg.ml-1 respectively. this extract showed a moderate toxicity on macrophages from balb/c mice. a dose of 100 mg/kg/day was effective when administered during 15 days by intraperitoneal route to balb/c mice infected experimentally.201020464129
serine proteases of leishmania amazonensis as immunomodulatory and disease-aggravating components of the crude laag vaccine.we previously demonstrated that intradermal and intramuscular vaccination with leishmania amazonensis promastigote antigens (laag) increases the susceptibility of balb/c mice to cutaneous leishmaniasis. in this study, we investigated the role played by serine and cysteine proteases as disease-promoting components of laag. mice were immunized by the intramuscular route with laag that was pre-treated with a pool of serine or cysteine protease inhibitors (spi and cpi, respectively) prior to infecti ...201020472030
type i ifn receptor regulates neutrophil functions and innate immunity to leishmania parasites.type i ifns exert diverse effector and regulatory functions in host immunity to viral and nonviral infections; however, the role of endogenous type i ifns in leishmaniasis is unclear. we found that type i ifnr-deficient (ifnar-/-) mice developed attenuated lesions and reduced ag-specific immune responses following infection with leishmania amazonensis parasites. the marked reduction in tissue parasites, even at 3 d in ifnar-/- mice, seemed to be indicative of an enhanced innate immunity. further ...201020483775
characterization of oxidative stress in leishmaniasis-infected or lps-stimulated macrophages using electrochemical impedance spectroscopy.the physiological changes caused by external stimuli can be employed as parameters to study pathogen infection in cells and the effect of drugs. among analytical methods, impedance is potentially useful to give insight into cellular behavior by studying morphological changes, alterations in the physiological state, production of charged or redox species without interfering with in vitro cellular metabolism and labeling. the present work describes the use of electrochemical impedance spectroscopy ...201020488689
kinetoplastid membrane protein-11 is present in promastigotes and amastigotes of leishmania amazonensis and its surface expression increases during metacyclogenesis.kinetoplastid membrane protein-11 (kmp-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. a suitable leishmaniasis vaccine candidate molecule must be expressed in amastigotes, the infective stage for mammals. however, the expression of kmp-11 in leishmania amastigotes has been a subject of controversy. we evaluated the expression of this molecule in logarithmic and stationary growth phase promastigotes, as well as in amastigotes ...201020512252
flow cytometric screening for anti-leishmanials in a human macrophage cell line.high-throughput drug screening methods against the intracellular stage of leishmania have been facilitated by the development of in vitro models of infection. the use of cell lines rather than primary cells facilitates these methods. peripheral blood mononuclear cell (pbmc) derived macrophages and thp-1 cells were infected with stationary phase egfp transfected leishmania amazonensis parasites and then treated with anti-leishmanial compounds. drug activity was measured using a flow cytometric ap ...201020540940
complete set of mitochondrial pan-edited mrnas in leishmania mexicana amazonensis lv78.editing of mrna transcribed from the mitochondrial cryptogenes nd8 (g1), nd9 (g2), g3, g4, nd3 (g5), rps12 (g6) was investigated in leishmania mexicana amazonensis, strain lv78, by amplification of the cdna, cloning and sequencing. for each of these genes, extensively and partially edited transcripts were found to be relatively abundant compared to the respective pre-edited molecules. moreover, the editing patterns observed in a majority of transcripts of each gene were consistent among themselv ...201020546801
vaccination with the leishmania infantum ribosomal proteins induces protection in balb/c mice against leishmania chagasi and leishmania amazonensis challenge.leishmania chagasi and leishmania amazonensis are the etiologic agents of different clinical forms of human leishmaniasis in south america. in an attempt to select candidate antigens for a vaccine protecting against different leishmania species, the efficacy of vaccination using leishmania ribosomal proteins and saponin as adjuvant was examined in balb/c mice against challenge infection with both parasite species. mice vaccinated with parasite ribosomal proteins purified from leishmania infantum ...201020601076
serine protease activities in leishmania (leishmania) chagasi promastigotes.the present work reports the isolation, biochemical characterization, and subcellular location of serine proteases from aqueous, detergent soluble, and culture supernatant of leishmania chagasi promastigote extracts, respectively, lcsii, lcsi, and lcsiii. the active enzyme molecular masses of lcsii were about 105, 66, and 60 kda; of lcsi, 60 and 58 kda; and of lcsiii, approximately 76 and 68 kda. optimal ph for the enzymes was 7.0 for lcsi and lcsiii and 8.5 for lcsii, and the optimal temperatur ...201020668879
efficacy of components from leaves of calophyllum brasiliense against leishmania (leishmania) amazonensis.leishmanicide potential of calophyllum brasiliense leaves on promastigote and amastigote of leishmania (leishmania) amazonensis is evaluated. the ld(50) of dichloromethane extract and hexane fraction for promastigotes was respectively 40 microg/ml and 20 microg/ml. in mouse peritoneal macrophages infected with leishmania amastigotes the infection index decreased respectively 100% and 84.2% in 80 microg/ml and 40 microg/ml concentrations of dichloromethane extract. hexane fraction decreased infec ...201019800777
novel role for the double-stranded rna-activated protein kinase pkr: modulation of macrophage infection by the protozoan parasite leishmania.the evolution of leishmania infection depends on the balance between microbicidal and suppressor macrophage functions. double-stranded rna (dsrna)-activated protein kinase r (pkr), a classic antiviral protein, is able to regulate a number of signaling pathways and macrophage functions. we investigated the possible role of pkr in the modulation of leishmania infection. our data demonstrated that leishmania amazonensis infection led to pkr activation and increased pkr levels. consistently, in macr ...201019812373
anti-leishmanial lindenane sesquiterpenes from hedyosmum angustifolium.the aim of this work is the isolation of anti-leishmanial compounds from the ethyl acetate extracts of the bark of hedyosmum angustifolium. we have successfully isolated and characterized five sesquiterpenes: one new compound (oxyonoseriolide, 1), one compound isolated for the first time from a natural source (hedyosmone, 2), and three known sesquiterpenes (onoseriolide, 3; chloranthalactone a, 4; and spathulenol, 5) that had not been previously isolated from h. angustifolium. the biological act ...201019830657
changes in macrophage membrane properties during early leishmania amazonensis infection differ from those observed during established infection and are partially explained by phagocytosis.understanding the impact of intracellular pathogens on the behavior of their host cells is key to designing new interventions. we are interested in how leishmania alters the electrical function of the plasma membrane of the macrophage it infects. the specific question addressed here is the impact of leishmania infection on macrophage membrane properties during the first 12h post-infection. a decrease of 29% in macrophage membrane capacitance at 3h post-infection indicates that the phagolysosome ...201019854174
in vitro sensitivity of leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis brazilian isolates to meglumine antimoniate and amphotericin b.resistance of leishmania parasites to specific chemotherapy has become a well-documented problem in the indian subcontinent in recent years but only a few studies have focused on the susceptibility of american leishmania isolates. our susceptibility assays to meglumine antimoniate were performed against intracellular amastigotes after standardizing an in vitro model of macrophage infection appropriate for leishmania (viannia) braziliensis isolates. for the determination of promastigote susceptib ...201019874570
antileishmanial activity of furoquinolines and coumarins from helietta apiculata.the bark infusion of h. apiculata are used to treat wound healing related to cutaneous leishmaniasis and as anti-inflammatory.201019879121
analysis of ribosomal rna transcription termination and 3' end processing in leishmania amazonensis.the control of gene expression in the human parasite leishmania occurs mainly at the post-transcriptional level. nevertheless, basic cell processes such as ribosome biogenesis seem to be conserved. mature ribosomal rnas (rrnas) are synthesized from typical rna polymerase i (pol i) promoters and processed by pathways analogous to other eukaryotes. to further understand pol i transcription control in these parasites, we have analyzed transcription termination and processing of the rdna in leishman ...201019914359
detection of leishmania (leishmania) amazonensis and leishmania (leishmania) infantum chagasi in brazilian bats.although bats are one of the most abundant mammals in the new world and are present in virtually all ecosystems, including urban and peri-urban environments, few studies have investigated the role of these animals in the epidemiological chain of leishmaniosis. here, we report a study of 683 bats captured in são paulo county (southeastern from brazil), which were screened by serology, parasitologic methods and polymerase chain reaction (pcr) for trypanosomatids. the indirect immunofluorescent ant ...201019939568
leishsmania (leishmania) amazonensis infection: muscular involvement in balb/c and c3h.hen mice.recent studies have provided some insights into leishsmania (leishmania) amazonensis muscular infection in dogs, although, muscular disease due to leishmaniasis has been poorly documented. the aim of our study was to evaluate involvement of leishmania in muscular infection of two distinct mouse strains (balb/c and c3h.he), with different genetic backgrounds. balb/c mice, susceptible to leishmania infection, showed, at the beginning of infection, a great number of infected macrophages among muscl ...201019944691
cytotoxic and anti-infective sesquiterpenes present in plagiochila disticha (plagiochilaceae) and ambrosia peruviana (asteraceae).a pharmacological screening of the ethanol extract and fractions of two peruvian medicinal plants, plagiochila disticha and ambrosia peruviana, led to the isolation and characterization of three ent-2,3-secoaromadendrane-type sesquiterpenoids, named plagiochiline a ( 1), i ( 2), and r ( 3), as well as of two pseudoguaianolids, damsin ( 4) and confertin ( 5), which exhibited significant cytotoxic activity against a panel of human tumor cell lines. compounds 1, 4, and 5 were also investigated for ...201019960415
in vitro and in vivo anti-leishmania activity of polysubstituted synthetic chalcones.the in vitro screening of 43 polysubstituted chalcones against leishmania amazonensis axenic amastigotes, led to the evaluation of 9 of them in a macrophage-infected model with the two other most infectious leishmania species prevalent in peru (l. braziliensis and l. peruviana). the five most active and selective chalcones were studied in vivo, resulting on the identification of two chalcones with high reduction parasite burden percentages.201019962891
partial protective responses induced by a recombinant cysteine proteinase from leishmania (leishmania) amazonensis in a murine model of cutaneous leishmaniasis.a 500 bp fragment encoding an isoform of cysteine proteinase from leishmania (leishmania) amazonensis was subcloned and expressed in the phis vector, resulting in a recombinant protein of 24 kda, rlacys24. in western blots of l. (l.) amazonensis extracts, antibodies directed to rlacys24 recognized a cysteine proteinase isoform of 30 kda. analysis by fluorescence-activated cell sorter showed a significantly higher expression of cd8(+) lymphocytes in animals immunized with rlacys24 plus cfa, where ...201019735658
leishmania spp. identification by polymerase chain reaction-restriction fragment length polymorphism analysis and its applications in french guiana.leishmania (viannia) guyanensis was for many years the only species commonly identified in french guiana, but precise species identifications were quite rare. we describe a new restriction fragment length polymorphism-polymerase chain reaction technique using a 615-bp fragment of the rna polymerase ii gene and 2 restriction enzymes, tspri and hgai. seven reference strains (leishmania (leishmania) amazonensis, leishmania (viannia) lainsoni, leishmania (viannia) braziliensis, l. (v.) guyanensis, l ...201019782495
leishmanicidal, trypanocidal, and cytotoxic activities of endophytic fungi associated with bioactive plants in brazil.one hundred and twenty-one isolates of endophytic fungi were recovered from leaves of the bioactive brazilian plant species ageratum myriadenia , palicourea tetraphylla , piptadenia adiantoides, and trixis vauthieri. all fungal isolates were cultivated in liquid media and crude extracts were obtained with ethyl acetate. the crude extracts were tested in bioassay panels using leishmania amazonensis , trypanosoma cruzi, the enzyme trypanothione reductase (tryr) from trypanosoma cruzi, and three hu ...201024031513
bioactivity of flavonoids isolated from lychnophora markgravii against leishmania amazonensis amastigotes.the bioactivity of the flavonoids pinostrobin (1), pinocembrin (2), tectochrysin (3), galangin 3-methyl ether (4), and tiliroside (5) isolated from lychnophora markgravii aerial parts was investigated in vitro against amastigote stages of leishmania amazonensis. the compounds were isolated by several chromatographic techniques and their chemical structures were established by esi-ms and nmr spectroscopic data. the flavonoids 1 and 3 were the most active compounds; they markedly reduced the viabi ...200919791501
separation of leishmania-infected macrophages by step-splitt fractionation.after a primary infection protocol of macrophages with leishmania amazonensis, the percentage of infection drops as infection progresses and the uninfected population of macrophages mask the effects of infection for electrophysiological studies. in order to increase or maintain the infection percentage, we introduce an enrichment process after primary infection, which increases the possibility of following the infection longer times than any known process. a membraneless separation technique, st ...200919800303
antileishmanial activity of 1,3,4-thiadiazolium-2-aminide in mice infected with leishmania amazonensis.the efficacy of two mesoionic derivatives (mi-h-h and mi-4-och(3)) was evaluated in cba/j mice infected with leishmania amazonensis. treatment with these compounds demonstrated that the mi-4-och(3) derivative and the reference drug meglumine antimoniate (glucantime) presented significant activity relative to an untreated control. no apparent hepatic or renal toxicity due to these mesoionic compounds was found.200919015338
membrane binding requirements for the cytolytic activity of leishmania amazonensis leishporin.to lyse cells, some pore-forming proteins need to bind to receptors on their targets. studying the binding requirements of leishmania amazonensis leishporin, we have shown that protease-treated erythrocytes are as sensitive to leishporin-mediated lysis as untreated cells, indicating that protein receptors are dispensable. similarly, carbohydrate receptors do not seem to be needed, since several sugars do not inhibit leishporin-mediated hemolysis. conversely, dipalmitoylphosphatidylcholine (dppc) ...200919737559
lipid microspheres loaded with antigenic membrane proteins of the leishmania amazonensis as a potential biotechnology application.lipid microspheres (lm) are excellent drug delivery or vaccines adjuvant systems and are relatively stable. the aim of this work is to develop and characterize a system that is able to encapsulate and present antigenic membrane proteins from leishmania amazonensis. membrane proteins are important for vaccine's formulation because these proteins come in contact with the host cell first, triggering the cell mediated immune response. this is a useful tool to avoid or inactivate the parasite invasio ...200919747691
effects of salivary gland homogenate from wild-caught and laboratory-reared lutzomyia longipalpis on the evolution and immunomodulation of leishmania (leishmania) amazonensis infection.we investigated the effects of lutzomyia longipalpis salivary glands homogenate of wild-caught and laboratory-reared vectors on the lesion evolution and immunomodulation of the infection caused by leishmania (leishmania) amazonensis. to compare the effect of both salivary glands homogenate (sgh), c57bl/6 mice were inoculated subcutaneously into the hind footpads or into the ear dermis with 10(6) promastigotes in the presence or not of sgh from wild-caught and laboratory-colonized sand flies. com ...200919751274
biochemical characterization of serine transport in leishmania (leishmania) amazonensis.in addition to its role as a protein component in leishmania, serine is also a precursor for the synthesis of both phosphatidylserine, which is a membrane molecule involved in parasite invasion and inactivation of macrophages, and sphingolipids, which are necessary for leishmania to differentiate into its infective forms. we have characterized serine uptake in both promastigote and amastigote forms of leishmania (leishmania) amazonensis. in promastigotes, kinetic data show a single, saturable tr ...200919041672
photodynamic vaccination of hamsters with inducible suicidal mutants of leishmania amazonensis elicits immunity against visceral leishmaniasis.leishmania, naturally residing in the phagolysosomes of macrophages, is a suitable carrier for vaccine delivery. genetic complementation of these trypanosomatid protozoa to partially rectify their defective heme-biosynthesis renders them inducible with delta-aminolevulinate to develop porphyria for selective photolysis, leaving infected host cells unscathed. delivery of released "vaccines" to antigen-presenting cells is thus expected to enhance immune response, while their self-destruction prese ...200919053149
dna and heparin chaperone the refolding of purified recombinant replication protein a subunit 1 from leishmania amazonensis.replication protein a (rpa) is a single-stranded dna-binding protein that has been implicated in dna metabolism and telomere maintenance. subunit 1 of rpa from leishmania amazonensis (larpa-1) has previously been affinity-purified on a column containing a g-rich telomeric dna. larpa-1 binds and co-localizes with parasite telomeres in vivo. here we describe the purification and characterization of native recombinant larpa-1 (rlarpa-1). the protein was initially re-solubilized from inclusion bodie ...200919056467
induction of autophagy correlates with increased parasite load of leishmania amazonensis in balb/c but not c57bl/6 macrophages.we investigated the role of autophagy in infection of macrophages by leishmania amazonensis. induction of autophagy by ifn-gamma or starvation increased intracellular parasite load and the percentages of infected macrophages from balb/c but not from c57bl/6 mice. in contrast, starvation did not affect the replication of either leishmania major or trypanosoma cruzi in balb/c macrophages. in balb/c macrophages, starvation resulted in increased monodansylcadaverine staining and in the appearance of ...200919070676
oral metabolism and efficacy of kalanchoe pinnata flavonoids in a murine model of cutaneous leishmaniasis.leishmaniasis is a parasitic disease that threatens 350 million people worldwide. in a search for new antileishmanial drugs, the in vitro activity of flavonoids from kalanchoe pinnata (crassulaceae) was previously demonstrated in infected cells. in order to demonstrate the safety and oral activity of k. pinnata, flavonoids were evaluated in vivo in a murine model of cutaneous leishmaniasis. daily oral doses of quercetin 3-o-alpha-l-arabinopyranosyl (1-->2)-alpha-l-rhamnopyranoside, quercetin 3-o ...200919085683
antigenic, microbicidal and antiparasitic properties of an l-amino acid oxidase isolated from bothrops jararaca snake venom.venoms from the bee apis mellifera, the caterpillar lonomia achelous, the spiders lycosa sp. and phoneutria nigriventer, the scorpions tityus bahiensis and tityus serrulatus, and the snakes bothrops alternatus, bothrops jararaca, bothrops jararacussu, bothrops moojeni, bothrops neuwiedi, crotalus durissus terrificus, and lachesis muta were assayed (800mug/ml) for activity against staphylococcus aureus. venoms from b. jararaca and b. jararacussu showed the highest s. aureus growth inhibition and ...200919101583
ivermectin-derived leishmanicidal compounds.in the present study a family of macrocyclic and acyclic analogues as well as seco-analogues of avermectins were prepared from commercial ivermectin (ivm) and their antileishmanial activity assayed against axenic promastigote and intracellular amastigote forms of leishmania amazonensis. contrarily to the filaricidal activity, the leishmanicidal potentiality of avermectin analogues does not appear to depend on the integrity of the non-conjugated delta(3,4)-hexahydrobenzofuran moiety. conjugated d ...200919114308
cratp as a new inhibitor of ecto-atpases of trypanosomatids.trypanosomatid protozoa include heteroxenic species some of them pathogenic for men, animals and plants. parasite membrane contains ecto-enzymes whose active sites face the external medium rather than the cytoplasm. herpetomonas sp. displayed a mg2+-dependent ecto-atpase activity, a mg-independent ecto-adpase and an ecto-phosphatase activity. both, the ecto-adpase and phosphatase activities were insensitive to cratp (chromium(iii) adenosine 5'-triphosphate complex). ecto-atpase activity was reve ...200919126268
in vitro and in vivo antitrypanosomatid activity of 5-nitroindazoles.previously, we have identified a series of 5-nitroindazoles with good antiprotozoal activities, against trypanosoma cruzi epimastigotes and trichomonas vaginalis. most of them have shown very low unspecific toxicity on macrophage cell lines. in the present work, we assayed these compounds on t. cruzi bloodstream trypomastigotes and leishmania promastigotes (leishmania amazonensis, leishmania braziliensis and leishmania infantum). derivatives 1, 2, 7 and 8 displayed remarkable trypanocidal activi ...200918706738
differential influence of gp63-like molecules in three distinct leptomonas species on the adhesion to insect cells.parasites belonging to the leptomonas genus have been used as model organisms for studying biochemical, cellular, and genetic processes unique to members of the trypanosomatidae family. in the present study, the cell-associated and extracellular peptidases of three leptomonas species, leptomonas collosoma, leptomonas samueli, and leptomonas wallacei, were assayed and characterized by gelatin-sodium dodecyl sulfate polyacrylamide gel electrophoresis. all parasites released metallopeptidases, wher ...200918830631
schwann cells as putative safe host cells for leishmania amazonensis. 200919157949
altered sterol profile induced in leishmania amazonensis by a natural dihydroxymethoxylated chalcone.the effects of the antileishmanial chalcone 2',6'-dihydroxy-4'-methoxychalcone (dmc) on leishmania amazonensis sterol composition and biosynthesis were investigated to obtain information about the mechanism of growth inhibition by dmc on this parasite.200919176591
activation of pi3k/akt signaling has a dominant negative effect on il-12 production by macrophages infected with leishmania amazonensis promastigotes.infection of macrophages with leishmania parasites does not result in the production of il-12. in addition, infection with leishmania suppresses il-12 production elicited by otherwise potent activators of il-12. we provide evidence that engagement of phosphatidyl inositol-3 kinase (pi3k) signaling during leishmania amazonensis infection leads to the prevention of il-12 p70 production at the level of transcription of its p40 subunit in bone marrow derived macrophages (bmdmphi). inhibition of pi3k ...200919186178
cytotoxic, immunosuppressive, trypanocidal and antileishmanial activities of basidiomycota fungi present in atlantic rainforest in brazil.one hundred three basidiomycota fungi representing 84 species and 17 families were collected from different atlantic rainforest in brazil. their basidiomes and fermentation broth extracts were screened in a bioassay panel that included three human cancer cells lines, human peripheral blood mononuclear cells (pbmcs), the enzyme trypanothione reductase (tryr) from trypanosoma cruzi, and amastigote forms of leishmania amazonensis. forty-two extracts representing 21 genera and 35 species presented a ...200919194781
ifn-beta impairs superoxide-dependent parasite killing in human macrophages: evidence for a deleterious role of sod1 in cutaneous leishmaniasis.type i ifns (ifn-alpha/beta) have only recently gained considerable attention as immunomodulators in nonviral infectious diseases. ifn-beta has been shown to protect, in a no-dependent manner, against murine old world leishmaniasis caused by leishmania major, but data in new world leishmaniasis are lacking. we found that ifn-beta dose-dependently increases parasite burden in leishmania amazonensis- as well as leishmania braziliensis-infected human macrophages, independent of endogenous or exogen ...200919201909
incorporation of antigenic gpi-proteins from leishmania amazonensis to membrane mimetic systems: influence of dppc/cholesterol ratio.the reconstitution of membrane proteins into liposomes is a useful tool to prepare antigenic components that induce immunity. we have investigated the influence of the dipalmitoylphosphatidylcholine (dppc)/cholesterol molar ratio on the incorporation of a gpi-protein from leishmania amazonensis on liposomes and langmuir monolayers. the latter system is a well behaved and practical model, for understanding the effect of variables such as surface composition and lipid packing on protein incorporat ...200919223036
trypanosoma cruzi gp63 proteins undergo stage-specific differential posttranslational modification and are important for host cell infection.the protozoan trypanosoma cruzi expresses multiple isoforms of the gp63 family of metalloproteases. polyclonal antiserum against recombinant gp63 of t. cruzi (tcgp63) was used to study tcgp63 expression and localization in this organism. western blot analysis revealed that tcgp63 is 61 kda in epimastigotes, amastigotes, and tissue culture-derived trypomastigotes but 55 kda in metacyclic trypomastigotes. antiserum specific for leishmania amazonensis gp63 specifically reacted with a 55-kda tcgp63 ...200919273559
transcriptional signatures of balb/c mouse macrophages housing multiplying leishmania amazonensis amastigotes.mammal macrophages (mphi) display a wide range of functions which contribute to surveying and maintaining tissue integrity. one such function is phagocytosis, a process known to be subverted by parasites like leishmania (l). indeed, the intracellular development of l. amazonensis amastigote relies on the biogenesis and dynamic remodelling of a phagolysosome, termed the parasitophorous vacuole, primarily within dermal mphi.200919302708
inhibitory activity of limonene against leishmania parasites in vitro and in vivo.limonene is a monoterpene that has antitumoral, antibiotic and antiprotozoal activity. in this study we demonstrate the activity of limonene against leishmania species in vitro and in vivo. limonene killed leishmania amazonensis promastigotes and amastigotes with 50% inhibitory concentrations of 252.0+/-49.0 and 147.0+/-46.0 microm, respectively. limonene was also effective against leishmania major, leishmania braziliensis and leishmania chagasi promastigotes. the treatment of l. amazonensis-inf ...200919321295
hiv aspartyl peptidase inhibitors interfere with cellular proliferation, ultrastructure and macrophage infection of leishmania amazonensis.leishmania is the etiologic agent of leishmanisais, a protozoan disease whose pathogenic events are not well understood. current therapy is suboptimal due to toxicity of the available therapeutic agents and the emergence of drug resistance. compounding these problems is the increase in the number of cases of leishmania-hiv coinfection, due to the overlap between the aids epidemic and leishmaniasis.200919325703
studying taxis in real time using optical tweezers: applications for leishmania amazonensis parasites.beads trapped by an optical tweezers can be used as a force transducer for measuring forces of the same order of magnitude as typical forces induced by flagellar motion. we used an optical tweezers to study chemotaxis by observing the force response of a flagellated microorganism when placed in a gradient of attractive chemical substances. this report shows such observations for leishmania amazonensis, responsible for leishmaniasis, a serious disease. we quantified the movement of this protozoan ...200919345110
effect of oral treatment with pyrazole carbohydrazide derivatives against murine infection by leishmania amazonensis.newly synthesized pyrazole carbohydrazide derivatives with substituents x = br/y = no(2) and x = no(2)/y = cl were independently investigated in the cba mouse model of cutaneous leishmaniasis. animals were infected with leishmania amazonensis and treated two weeks after the parasitic infection with the pyrazole carbohydrazides for 45 days. oral treatment with both compounds controlled evolution of footpad cutaneous lesions and dissemination of parasites to draining lymph nodes. nitric oxide gene ...200919346377
leishmania amazonensis promastigotes induce and are killed by neutrophil extracellular traps.neutrophils are short-lived leukocytes that die by apoptosis, necrosis, and netosis. upon death by netosis, neutrophils release fibrous traps of dna, histones, and granule proteins named neutrophil extracellular traps (nets), which can kill bacteria and fungi. inoculation of the protozoan leishmania into the mammalian skin causes local inflammation with neutrophil recruitment. here, we investigated the release of nets by human neutrophils upon their interaction with leishmania parasites and nets ...200919346483
altered dendritic cell phenotype in response to leishmania amazonensis amastigote infection is mediated by map kinase, erk.initiation of productive immune responses against leishmania depends on the successful transition of dendritic cells (dc) from an immature to a mature phenotype. this process is characterized by high cd40 surface expression as well as interleukin-12 production, which are frequently seen in response to l. major infection. in vivo footpad infection of c3heb/fej mice for 7 days with l. amazonensis promoted an immature cd11c(+) dc phenotype characterized by both significantly low cd40 surface expres ...200919349356
modulation of p2x(7) purinergic receptor in macrophages by leishmania amazonensis and its role in parasite elimination.the purinergic p2x(7) receptor is a membrane protein of leucocytes involved in the clearance of intracellular bacteria such as chlamydia and mycobacterium. in this work, we investigated the role and modulation of macrophage p2x(7)r in intracellular infection with the protozoan parasite leishmania amazonensis. upon infection, isolated murine macrophages displayed enhanced expression of p2x(7)r and were significantly more responsive to extracellular atp (atpe)-induced pore opening, as demonstrated ...200919439191
saliva of laboratory-reared lutzomyia longipalpis exacerbates leishmania (leishmania) amazonensis infection more potently than saliva of wild-caught lutzomyia longipalpis.in order to compare the saliva effect from wild-caught and lab-reared l. longipalpis on the development of experimental cutaneous leishmaniasis, c57bl/6 mice were inoculated subcutaneously into the hind footpads with promastigotes of l. (l.) amazonensis plus salivary gland lysate from wild-caught (sgl-w) and lab-colonized (sgl-c) vectors. lesion sizes were significantly larger in the mice infected with both saliva compared to mice infected with parasites alone; moreover, the lesions caused by pa ...200919454323
activity of physalins purified from physalis angulata in in vitro and in vivo models of cutaneous leishmaniasis.we have previously demonstrated the immunomodulatory effects of physalins, secosteroids purified from physalis angulata. here we investigate the antileishmanial activity of physalins in vitro and in vivo in a model of cutaneous leishmaniasis.200919454526
antiplasmodial and antileishmanial activities of phylloseptin-1, an antimicrobial peptide from the skin secretion of phyllomedusa azurea (amphibia).the development of drug resistance by infectious agents represents a major hindrance for controlling parasitic diseases and has stimulated the search for new compounds. we have previously shown that phylloseptin-1 (ps-1), a cationic peptide from the skin secretion of phyllomedusa azurea, exhibited potent antimicrobial activity. now we evaluate the effect of ps-1 on leishmania amazonensis and plasmodium falciparum. concentrations as low as 0.5 microg/ml of ps-1 exhibited antileishmanial activity ...200919460376
cooperation between apoptotic and viable metacyclics enhances the pathogenesis of leishmaniasis.mimicking mammalian apoptotic cells by exposing phosphatidylserine (ps) is a strategy used by virus and parasitic protozoa to escape host protective inflammatory responses. with leishmania amazonensis (la), apoptotic mimicry is a prerogative of the intramacrophagic amastigote form of the parasite and is modulated by the host. now we show that differently from what happens with amastigotes, promastigotes exposing ps are non-viable, non-infective cells, undergoing apoptotic death. as part of the n ...200919478944
the use of azythromycin and n-methyl glucamine for the treatment of cutaneous leishmaniasis caused by leishmania (leishmania) amazonensis in c57bl6 mice.the first choice treatment for cutaneous leishmaniasis is n-methyl glucamine: it has high toxicity, requires parenteral administration and cure is not always reached. azythromycin showed in vitro action and controversial results in humans with the disease.200919503979
medicinal plants from the yanesha (peru): evaluation of the leishmanicidal and antimalarial activity of selected extracts.ninety-four ethanolic extracts of plants used medicinally by the yanesha, an amazonian peruvian ethnic group, for affections related to leishmaniasis and malaria were screened in vitro against leishmania amazonensis amastigotes and against a plasmodium falciparum chloroquine resistant strain.200919514108
identification of macrosialin (cd68) on the surface of host macrophages as the receptor for the intercellular adhesive molecule (icam-l) of leishmania amazonensis.the intercellular adhesive molecule, icam-l, of leishmania amazonensis is known to block the attachment as well as internalisation of leishmania for infection in host macrophages. we employed monoclonal antibodies (mab) to the surface molecules of a macrophage to block the attachment of icam-l to the macrophage surface and identified that cd68 macrosialin is likely the receptor molecule on the macrophage for icam-l. we then demonstrated physical interaction between icam-l and macrosialin by co-i ...200919540239
comparative study of serologic tests for the diagnosis of asymptomatic visceral leishmaniasis in an endemic area.serologic tests have been widely used for the diagnosis of asymptomatic visceral leishmaniasis. this study evaluated five serologic tests used for the diagnosis of asymptomatic infection: enzyme-linked immunosorbent assay (elisa) using promastigote antigen (elisap), elisa using recombinant k39 (elisa rk39), and k26 (elisa rk26) antigens, an indirect immunofluorescence test using leishmania (leishmania) amazonensis promastigote antigen (iift), and an immunochromatographic test using rk39 antigen ...200919556562
comparison of serological and parasitological methods for cutaneous leishmaniasis diagnosis in the state of paraná, brazil.we evaluated the effectiveness of serological and parasitological methods for cutaneous leishmaniasis (cl) diagnosis in patients from the central region of paraná state, southern brazil. five groups were compared: clinical diagnosis, parasitological diagnosis, communicants, inhabitants of a non-endemic area and carriers of other etiologies. two antigens were prepared from promastigotes of leishmania (viannia) braziliensis and leishmania (leishmania) amazonensis for indirect immunofluorescence as ...200919578630
leishmania amazonensis growth inhibitors: biological and theoretical features of sulfonamide 4-methoxychalcone derivatives.current drugs for treating leishmaniasis are still associated with significant toxicity and failure rates. thus, new effective and less toxic antileishmanial agents are still in need. herein, we tested a series of sulfonamide 4-methoxychalcone derivatives against l. amazonensis promastigote and amastigote forms to identify its antileishmanial profile against this species compared to l. braziliensis. in addition, we used molecular modeling tools to determine stereoelectronic features that may lea ...200919629593
ta'ta', huayani: perception of leishmaniasis and evaluation of medicinal plants used by the chayahuita in peru. part ii.a knowledge attitude and practice study centred on leishmaniasis and its treatment was performed among the chayahuita, an amazonian peruvian ethnic group living in an endemic area. this study documents traditional chayahuita plant's use and disease concepts. also, activity of some medicinal plants used by the chayahuita is highlighted and discussed.200919631728
evaluation of leishmania species reactivity in human serologic diagnosis of leishmaniasis.the sensitivities and specificities of igg-elisa and igg flow cytometry based techniques using different leishmania species were determined using sera collected from 40 cutaneous or visceral leishmaniasis patients. the flow cytometry technique, using promastigote parasite forms, performed better than total soluble extract igg-elisa. at the species level, the use of leishmania amazonensis and leishmania major as antigens in enzyme linked immunosorbent assay (elisa) decreased the overall sensitivi ...200919635870
in vitro activity of the essential oil of cymbopogon citratus and its major component (citral) on leishmania amazonensis.leishmaniasis causes considerable mortality throughout the world, affecting more than 12 million people. cymbopogon citratus (dc) stapf, family poaceae, is a widely used herb in tropical countries and is also known as a source of ethnomedicines. in this study, the inhibitory effect and the morphological and ultrastructural alterations on leishmania amazonensis by the essential oil (eo) of c. citratus and its main constituent, citral, were evaluated. the results showed that the antiproliferative ...200919669793
synthesis, characterization and evaluation of antileishmanial activity of copper(ii) with fluorinated α-hydroxycarboxylate ligands.in this study, cu(ii) complexes with fluorinated ligands were produced aiming at the development of new, less toxic antileishmanial metallodrugs. complexes of the general formula cul2 (l = lactate, trifluorolactate, 2-hydroxyisobutyrate, trifluoro-2-hydroxyisobutyrate) were synthesized in methanolic medium, purified by crystallization and characterized by elemental analysis and electronic and infrared spectroscopies. in vitro experiments with leishmania amazonensis promastigotes showed that the ...200919680603
[identification of leishmania species isolated in human cases in mato grosso do sul, by means of the polymerase chain reaction].leishmaniases are endemic zoonoses in the state of mato grosso do sul. their etiological agents in this region of brazil are leishmania (leishmania) chagasi, leishmania (leishmania) amazonensis and leishmania (viannia) braziliensis. the polymerase chain reaction (pcr) is a tool with high specificity and sensitivity for identifying leishmania species. this study examined 39 cryopreserved isolates of leishmania that had been collected by bone marrow aspiration and/or lesion biopsy, depending on th ...200919684979
increase of nk cells and proinflammatory monocytes are associated with the clinical improvement of diffuse cutaneous leishmaniasis after immunochemotherapy with bcg/leishmania antigens.diffuse cutaneous leishmaniasis (dcl) is characterized by disseminated lesions and the absence of a specific cellular immune response. here, the immunochemotherapy outcome of a patient with dcl from amazonian brazil infected with leishmania (leishmania) amazonensis is presented. after several unsuccessful chemotherapy treatment regimens and many relapses, a monthly immunotherapy scheme of l. amazonensis ph8 plus l. (viannia) braziliensis m2903 monovalent vaccines associated with bacillus calmett ...200919706899
nf-kappab-mediated repression of inos expression in leishmania amazonensis macrophage infection.host invasion by pathogens is frequently associated with the activation of nuclear factor kappab (nf-kappab), which modulates the expression of genes involved in the immunological response of the host. however, pathogens may also subvert these mechanisms to secure their survival. we describe the effect of leishmania amazonensis infection on nf-kappab transcriptional factor activation in macrophages and the subsequent reduction in inducible nitric oxide synthase (inos) expression. l. amazonensis ...200919712696
a novel organotellurium compound (rt-01) as a new antileishmanial agent.leishmaniasis is a neglected disease and endemic in developing countries. a lack of adequate and definitive chemotherapeutic agents to fight against this infection has led to the investigation of numerous compounds. the aim of this study was to investigate the effect of rt-01, an organotellurane compound presenting biological activities, in 2 experimental systems against leishmania amazonensis. the in vitro system consisted of promastigotes and amastigotes forms of the parasite, and the in vivo ...200919724693
preparation and antileishmanial activity of lipophilic n-alkyl diamines.we report in this work the preparation and the in vitro antileishmanial activity of a series of long chains n-monoalkylated diamines and two pyridinediamine derivatives. several compounds, tested for their in vitro antiproliferative activity against leishmania amazonensis and leishmania chagasi, displayed a good inhibition of parasite growth, with ic(50) below 10 microm. compounds 10 (n-dodecyl-1,2-ethanediamine), 15 (n-decyl-1,3-propanediamine) and 20 (n-dodecyl-1,4-butanediamine) were 7.3, 2.6 ...200918262385
aureobasidium-derived soluble branched (1,3-1,6) beta-glucan (sophy beta-glucan) enhances natural killer activity in leishmania amazonensis-infected mice.the beta-glucans derived from yeast cell walls have been reported for having many immunomodulatory activities in vivo and in vitro. in this study, aureobasidium-derived soluble branched (1,3-1,6) beta-glucan (sophy beta-glucan) was checked for natural killer (nk) activity and for the production of ifn-gamma and il-4 in leishmania amazonensis infection. the main experiment was performed with a group of female c57bl/6 and balb/c mice, orally supplemented with 5% of sophy beta-glucan and infected w ...200919967081
epidemiological study on leishmaniasis in an area of environmental tourism and ecotourism, state of mato grosso do sul, 2006-2007.the aims of this study were to carry out a serological survey of canine leishmaniasis and identify the phlebotomine fauna in the urban area of bonito, mato grosso do sul. the serological survey was conducted on a sample of 303 dogs, by means of the indirect immunofluorescence test. phlebotomines were captured using automated light traps. the serological survey found that 30% of the dogs were seropositive, both from the center and from all districts of the town. a total of 2,772 specimens of phle ...200919967228
effect of oral treatment with the essential oil from chenopodium ambrosioides against cutaneous leishmaniasis in balb/c mice, caused by leishmania amazonensis.the aromatic herb chenopodium ambrosioides is widely known for its antiparasitic activity. the aim of this study was to investigate the antileishmanial effect of chenopodium oil administered by the oral route at different doses and to compare its action to conventional, clinically used drugs.200919887812
phlebotomine fauna (diptera: psychodidae) of an american cutaneous leishmaniasis endemic area in the state of mato grosso do sul, brazil.the occurrence of an outbreak of cutaneous leishmaniasis associated with leishmania (leishmania) amazonensis in the municipality of bela vista, state of mato grosso do sul, brazil, and the absence of information on its vectors in this area led the authors to undertake captures of phlebotomine sand flies, using shannon traps and automatic cdc light traps, in domiciles, forested areas and animal shelters from february 2004-january 2006. a total of 808 specimens belonging to 18 sandfly species have ...200919820827
leishmania-released nucleoside diphosphate kinase prevents atp-mediated cytolysis of macrophages.leishmania amazonensis was found to release nucleoside diphosphate kinase (ndk)-a stable enzyme capable of decreasing extracellular atp. the release of this enzyme from leishmania results in its progressive accumulation extracellularly as they replicate, peaking at the stationary phase in vitro. the released ndk is immunoprecipitable and constitutes approximately 40% of its total activities and proteins. the retention of a known cytosolic protein by wild type cells and a fluorescent protein by d ...200818242727
leishmania amazonensis: effects of heat shock on ecto-atpase activity.in this work we demonstrated that promastigotes of leishmania amazonensis exhibit an mg-dependent ecto-atpase activity, which is stimulated by heat shock. the mg-dependent atpase activity of cells grown at 22 and 28 degrees c was 41.0+/-5.2 nmol pi/h x 10(7)cells and 184.2+/-21.0 nmol pi/h x 10(7)cells, respectively. when both promastigotes were pre-incubated at 37 degrees c for 2h, the atpase activity of cells grown at 22 degrees c was increased to 136.4+/-10.6 nmol pi/h x 10(7) whereas that th ...200818295760
early infection with leishmania major restrains pathogenic response to leishmania amazonensis and parasite growth.experimental models of infection with leishmania spp. have provided knowledge of several immunological events involved in the resistance mechanism used by the host to restrain parasite growth. it is well accepted that concomitant immunity exists, and there is some evidence that it would play a major role in long-lasting acquired resistance to infection. in this paper, the resistance to leishmania amazonensis infection in c57bl/6 mice infected with leishmania major was investigated. c57bl/6 mice, ...200818313021
inhibition of in vivo leishmanicidal mechanisms by tempol: nitric oxide down-regulation and oxidant scavenging.tempol (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy) has long been known to protect experimental animals from the injury associated with oxidative and inflammatory conditions. in the latter case, a parallel decrease in tissue protein nitration levels has been observed. protein nitration represents a shift in nitric oxide actions from physiological to pathophysiological and potentially damaging pathways involving its derived oxidants such as nitrogen dioxide and peroxynitrite. in infectious di ...200818313408
leishmania amazonensis: xylitol as inhibitor of macrophage infection and stimulator of macrophage nitric oxide production.xylitol is a sugar alcohol being explored for clinical uses. the aim was to evaluate the effects of xylitol on leishmania amazonensis-infected j774a.1 macrophages. macrophages were infected with l. amazonensis for 3h, washed and incubated with 2.5 or 5.0% xylitol for 24, 48, and 72 h at 37 degrees c. infection indexes for macrophages incubated only in medium were compared to those treated with xylitol. cell viability and nitric oxide production were determined each time. xylitol did not affect l ...200818316079
antimicrobial and antileishmanial xanthones from the stem bark of allanblackia gabonensis (guttiferae).the phytochemical study of stem bark of allanblackia gabonensis has resulted in the isolation and characterisation of one new xanthone derivative, named allanxanthone d, together with 10 known compounds, including 6 xanthones derivatives, allanxanthone a, 1,5-dihydroxyxanthone, 1,7-dihydroxyxanthone and 1,3,6,7-tetrahydroxy-2-(3-methylbut-2-enyl)xanthone, forbexanthone, 6-deoxyisojacareubin, one polyisoprenylated benzophenone, guttiferone f, one flavanol, epicathechin, two phytosterols, beta-sit ...200818322848
biochemical and biophysical properties of a highly active recombinant arginase from leishmania (leishmania) amazonensis and subcellular localization of native enzyme.arginase (l-arginine amidinohydrolase, e.c. 3.5.3.1) is a metalloenzyme that catalyses the hydrolysis of l-arginine to l-ornithine and urea. in leishmania spp., the biological role of the enzyme may be involved in modulating no production upon macrophage infection. previously, we cloned and characterized the arginase gene from leishmania (leishmania) amazonensis. in the present work, we successfully expressed the recombinant enzyme in e. coli and performed biochemical and biophysical characteriz ...200818400316
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