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1.
Passero LF Laurenti MD Tomokane TY Corbett CE Toyama MH 《Parasitology research》2008,102(5):1025-1033
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 polymorphonuclear, mononuclear, and amastigote cells. Additionally, infected macrophages treated
with PLA2 were able to generate prostaglandin E2 (PGE2). Cytokine quantification showed that the supernatant from infected
macrophages presented moderate and high amounts of IL-2 and IL-10, respectively. However, in PLA2-treated infected macrophages,
suppression of IL-2 levels occurred, but not of IL-10 levels. Observation also revealed that both the supernatant and lysate
of L. (L.) amazonensis promastigotes exhibited PLA2 activity, which, in the presence of dexamethasone, showed no reduction in their activities;
while glucocorticoid maintained the ability of promastigote forms to infect macrophages, which presented values similar to
controls. In conclusion, the results indicate that PLA2 may be a progression factor for cutaneous leishmaniasis, since the
PLA2 effect suppressed IL-2 levels and generated PGE2, an inflammatory lipid mediator. 相似文献
2.
Silva-Lopez RE Morgado-Díaz JA Chávez MA Giovanni-De-Simone S 《Parasitology research》2007,101(6):1627-1635
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 benzamidine (Bza) inhibitors, which are potential Leishmania proteases inhibitors, in all experimental conditions reduced the parasite viability, with regard to time dependence. On the other hand, N-tosyl-lysine chloromethyl ketone (TLCK) did not significantly affect the parasite viability, as it was poor Leishmania enzymes inhibitor. Ultrastructural analysis demonstrated that both Bza and TPCK induced changes in the flagellar pocket region with membrane alteration, including bleb formation. However, TPCK effects were more pronounced than those of Bza in Leishmania flagellar pocket in plasma membrane, and intracellular vesicular bodies was visualized. ShPI-I proved to be a powerful inhibitor of L. amazonensis serine proteases and the parasite viability. The ultrastructural alterations caused by ShPI-I were more dramatic than those induced by the classical inhibitors. Vesiculation of the flagellar pocket membrane, the appearance of a cytoplasmic vesicle that resembles an autophagic vacuole, and alterations of promastigotes shape resulted. 相似文献
3.
Karina?M.?Rebello Luzia?M.?C.?C?rtes Bernardo?A.?S.?Pereira Bernardo?M.?O.?Pascarelli Suzana?C?rte-Real Léa?C.?Finkelstein Rosa?T.?Pinho Claudia?M.?d’Avila-Levy Carlos?R.?Alves 《Parasitology research》2009,106(1):95-104
Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and
is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we
obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of
63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the
peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data
together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation
of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant
and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that
some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues
in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection. 相似文献
4.
Brenzan MA Nakamura CV Prado Dias Filho B Ueda-Nakamura T Young MC Aparício Garcia Cortez D 《Parasitology research》2007,101(3):715-722
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 leaves of Calophyllum brasiliense Cambess (Clusiaceae). The isolated compound was characterized using spectral analyses by UV, infrared, nuclear magnetic resonance
of 1H, 13C, distortionless enhancement by polarization transfer, correlation spectroscopy, heteronuclear multiple bond correlation,
and heteronuclear multiple quantum coherence. The compound (−) mammea A/BB showed significant activity against promastigote
and amastigote forms of L. amazonensis, with IC50 (50% inhibition concentration of cell growth) at a concentration of 3.0 and 0.88 μg/ml and IC90 (90% inhibition concentration of cell growth) of 5.0 and 2.3 μg/ml, respectively. The coumarin (−) mammea A/BB showed no
cytotoxicity against J774G8 macrophages in culture, when it was tested at high concentrations that inhibited promastigote
forms. Electron microscopy studies revealed considerable ultrastructural changes when promastigote forms of L. amazonensis were treated with 3.0 μg/ml of the coumarin (−) mammea A/BB for 72 h. We observed significant changes such as mitochondrial
swelling with concentric membranes in the mitochondrial matrix and intense exocytic activity in the region of the flagellar
pocket. Other alterations included the appearance of binucleate cells and multiple cytoplasmic vacuolization. These results
showed that (−) mammea A/BB is a potent growth inhibitor of L. amazonensis and caused important changes in the parasite’s ultrastructure. This study provided new perspectives on the development of
novel drugs with leishmanicidal activity obtained from natural products. 相似文献
5.
Silva-Lopez RE Morgado-Díaz JA Alves CR Côrte-Real S Giovanni-De-Simone S 《Parasitology research》2004,93(4):328-331
Extracellular proteolytic activity was detected in a Leishmania (L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin–agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. (L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking. 相似文献
6.
Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails. 相似文献
7.
Marta Regina Santin Adriana Oliveira dos Santos Celso Vataru Nakamura Benedito Prado Dias Filho Izabel Cristina Piloto Ferreira Tania Ueda-Nakamura 《Parasitology research》2009,105(6):1489-1496
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 activity of EO on promastigotes
and axenic amastigotes, and intracellular amastigote forms of L. amazonensis was significantly better than citral, and indicated a dose-dependent effect. Neither compound showed a cytotoxic effect on
macrophage strain J774G8. The promastigote forms of L. amazonensis underwent remarkable morphological and ultrastructural alterations compared with untreated cultures. These alterations were
visible by light, scanning, and transmission electron microscopy of promastigotes treated with EO and citral at concentrations
corresponding to the IC50 (1.7 and 8.0 μg/ml) and IC90 (3.2 and 25 μg/ml), respectively, after 72 h of incubation. This study revealed that citral-rich essential oil from C. citratus has promising antileishmanial properties, and is a good candidate for further research to develop a new anti-protozoan drug. 相似文献
8.
9.
One fundamental step of Leishmania-macrophage interaction is the phase of parasite internalization through an endocytic process, with the formation of the parasitophorous vacuole (PV). The present study analyzed this process using two approaches. First, to investigate the host cell proteins which take part in this compartment, the macrophage surface was biotinilated and allowed to interact with both Leishmania forms, the PV was then isolated, and the biotinilated proteins were analyzed by Western blot. The results obtained showed that the isolated PV from macrophages infected for 60 min with infective promastigotes displayed high molecular weight proteins, 220 kDa and 180 kDa, contrary to the isolated PV obtained from amastigotes. The isolated PV from amastigotes, after 60 min interaction, displayed a faint, biotinilated protein profile, in contrast to the PV containing amastigote which, after 30 min interaction, displayed a strong protein profile in the range of 120 kDa and 40-60 kDa. The biotinilated protein profile may represent proteins distributed in the PV membrane and may also correspond to biotinilated proteins incorporated by the intracellular parasite, as observed by confocal microscopy. In a second approach, to investigate the PV phospholipid composition, macrophages were incubated with (32)P, allowed to interact with the parasites, and the isolated PV was then processed for phospholipid analysis by thin layer chromatography and scintillation counting. An increase in the levels of lysophosphatidylcholine was observed in infected macrophages. The isolated PV from infective promastigotes and amastigotes, after 60 min interaction, displayed high levels of phosphatidylcholine. Then the PV was ruptured and the intravacuolar parasite's (32)P phospholipid composition was analyzed by TLC; and labeling of the parasites was found, suggesting that phospholipids from the macrophage are transferred to the parasite. Taken together, the results obtained show that several proteins and phospholipids found in the plasma membrane of the macrophage are also found in the PV compartment. 相似文献
10.
Bardia A Tiwari SK Gunisetty S Anjum F Nallari P Habeeb MA Khan AA 《Inflammation research》2012,61(4):359-365
Objective
The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC). 相似文献11.
12.
María del Rosario Robles James E. Loudon John M. Kinsella Mandala Hunter-Ishikawa David S. Miller Michelle L. Sauther Frank P. Cuozzo 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2010,55(3):270-275
Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and
the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini
hosts will only be proven when additional records fill in the gaps in their distribution. 相似文献
13.
14.
Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised hosts. In cystic fibrosis (CF), P. aeruginosa causes acute and chronic lung infections that result in significant morbidity and mortality. P. aeruginosa possesses several traits that contribute to its ability to colonize and persist in acute and chronic infections. These include
high resistance to antimicrobials, ability to form biofilms, plethora of virulence products, and metabolic versatility. In
P. aeruginosa, a cell-to-cell communication process termed quorum sensing (QS) regulates many of these factors that contribute to its pathogenesis.
Recent evidence suggests that the CF lung environment presents a specialized niche for P. aeruginosa. The relationship of P. aeruginosa QS, biofilm formation, and the CF lung environment is discussed. 相似文献
15.
Fidelis Cho-Ngwa Melanie Abongwa Moses N Ngemenya Kennedy D Nyongbela 《BMC complementary and alternative medicine》2010,10(1):62
Background
The current treatment of onchocerciasis relies on the use of ivermectin which is only microfilaricidal and for which resistant parasite strains of veterinary importance are increasingly being detected. In the search for novel filaricides and alternative medicines, we investigated the selective activity of crude extracts of Margaritaria discoidea and Homalium africanum on Onchocerca ochengi, a model parasite for O. volvulus. These plants are used to treat the disease in North West Cameroon. 相似文献16.
Emily Staples Beatriz Morillo-Gutierrez Jessica Davies Daniel Petersheim Michel Massaad Mary Slatter Dimitra Dimou Rainer Doffinger Scott Hackett Dinkantha Kumararatne James Hadfield Matthew D. Eldridge Raif S. Geha Mario Abinun James E. D. Thaventhiran 《Journal of clinical immunology》2017,37(5):415-418
17.
Passero LF Carvalho AK Bordon ML Bonfim-Melo A Toyama MH Corbett CE Laurenti MD 《Inflammation research》2012,61(3):255-263
Objective
Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis. 相似文献18.
The BactiCard Neisseria (Remel, USA) is a chromogenic enzyme substrate system for identifying Neisseria gonorrhoeae, Neisseria meningitidis, Neisseria lactamica, and Moraxella catarrhalis. The identification system consists of a card with four test circles impregnated with chromogenic substrates for indoxyl
butyrate esterase (IB), prolyl aminopeptidase (PRO), γ-glutamyl aminopeptidase (GLUT), and ?-galactosidase (BGAL). These substrates
permit the identification of Moraxella catarrhalis, Neisseria gonorrhoeae, Neisseria meningitidis, and Neisseria lactamica, respectively. After hydration of the circles with buffer, colonies from growth on selective media or a subculture are applied
to the four circles. IB and BGAL reactions are read for a blue-green color after 2 and 15 min, respectively. PRO and GLUT
reactions are read at 15 min for a red color after addition of a developer reagent. Identifications obtained with the BactiCard
Neisseria were compared with those obtained using conventional procedures for 558 isolates in a blinded fashion. The BactiCard Neisseria identified 100% of 254 Neisseria gonorrhoeae, 100% of 125 Neisseria meningitidis, 53 (98.2%) of 54 Neisseria lactamica, and 123 (98.4%) of 125 Moraxella catarrhalis isolates. The BactiCard Neisseria is an accurate and rapid system for identification of these microorganisms in the clinical laboratory.
Electronic Publication 相似文献
19.
Vanegas G Quiñones W Carrasco-López C Concepción JL Albericio F Avilán L 《Parasitology research》2007,101(6):1511-1516
Enolase is a glycolytic and gluconeogenic enzyme also found on the surface of several eukaryotic and prokaryotic cells where
it acts as plasminogen binding protein. Leishmania mexicana, one of the causative agents of Leishmaniasis, binds plasminogen and, in this parasite, enolase has been previously found
associated with the external face of the plasma membrane. In this work, we show that the purified recombinant enolase has
plasminogen binding activity indicating that, at the surface of the parasite, the protein may function as one of the plasminogen
receptors. An internal motif 249AYDAERKMY257, similar to the nine amino-acid internal plasminogen-binding motif in Streptococcus pneumoniae enolase, is responsible for plasminogen interaction with the parasite enolase. Anti-enolase antibodies inhibited up to 60%
of plasminogen binding on live parasites indicating that enolase act as a plasminogen receptor on the parasite. The fact that
enolase acts as a possible plasminogen receptor in vivo makes this protein a promising target for therapy. 相似文献
20.
Yamazaki K Takazoe M Tanaka T Ichimori T Saito S Iida A Onouchi Y Hata A Nakamura Y 《Journal of human genetics》2004,49(12):664-668
Crohn disease (CD) is an inflammatory bowel disease characterized by chronic transmural, segmental, and typically granulomatous inflammation of the gut. Recently, two novel candidate gene loci associated with CD, SLC22A4 and SLC22A5 on chromosome 5 known as IBD5 and DLG5 on chromosome 10, were identified through association analysis of Caucasian CD patients. We validated these candidate genes in Japanese patients with CD and found a weak but possible association with both SLC22A4 (P=0.028) and DLG5 (P=0.023). However, the reported genetic variants that were indicated to be causative in the Caucasian population were completely absent in or were not associated with Japanese CD patients. These findings imply significant differences in genetic background with CD susceptibility among different ethnic groups and further indicate some difficulty of population-based studies. 相似文献