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1.
Trypanosoma cruzi epimastigotes were exposed to varying micromolar concentrations of the dinitroaniline antitubulin trifluralin. The effects
of trifluralin on parasite proliferation, metacyclogenesis, morphology, and uptake of horseradish peroxidase (HRP) were investigated.
Parasites exposed to the antitubulin showed some ultrastructural alterations, i.e., formation in some parasites of large,
membrane-delimited vacuoles and a significant decrease in the number of HRP-positive reservosomes. Whereas there was no perceptible
change in the morphology of either subpellicular or flagellar microtubules, there was a significant inhibition of proliferation
and metacyclogenesis at trifluralin concentrations in excess of 100 μM. These concentrations were considerably higher than those reported to produce similar results in Leishmania spp. and T. brucei brucei.
Received: 18 June 1998 / Accepted: 12 November 1998 相似文献
2.
Fathy Abdel-Ghaffar Abdel-Rahman Bashtar Heinz Mehlhorn Khaled AL-Rasheid Kareem Morsy 《Parasitology research》2011,108(1):219-225
Out of 600 marine fish from the Red Sea belonging to three different species that were collected and examined for microsporidian
parasites, 87 (14.5%) fish were found to be infected. The infection was recorded as cysts or xenomas embedded in the gut epithelium
and the peritoneal cavity of the three fish species. The highest percent of infection with microsporidian parasites was recorded
in Saurida tumbil 19.5% (39/200) followed by Pagrus pagrus 15% (45/300) and the lowest percent of infection was recorded in Epinephelus chlorostigma 3% (three out of 100). After rupture of the cysts, the spores were released and examined by light microscopy. Each spore
was elongated to ellipsoidal in shape and possessed a posterior vacuole which is characteristic to phylum Microspora. They
measure 1.6 ± 0.5 μm (1.5–2.4 μm) × 1.3 ± 0.1 μm (1.3–2.0 μm) in Saurida tumbil and Pagrus pagrus, respectively. The spores of Pleistophora sp recorded from E. chlorostigma were ovoid to pyriform in shape and measure 1.9 ± 0.5 μm (1.8–2.7 μm) × 1.6 ± 0.4 μm (1.5–2.4 μm). 相似文献
3.
4.
Azevedo C 《Parasitology research》2001,87(4):326-330
A coccidian species, Goussia clupearum (L.) is reported to parasitize the liver of a new host, Belone belone (Teleostei: Belonidae), caught on the Atlantic coast at the north of Portugal. The parasitophorous vacuole containing oocysts
was attached to the host's liver cells. Spherical oocysts (∼ 21.2 μm diameter), each containing four ellipsoidal elongated
sporocysts (10.5 × 6.3 μm), were enclosed in the parasitophorous vacuole. Each sporocyst contained two sporozoites. The micropyle
was absent, but a polar granule (without Stieda body) was present. Each sporozoite possessed four refractile bodies. During
sporoblastogenesis and sporogenesis, one or two dense polar bodies were found within the oocysts. They were composed of a
dense homogeneous core, surrounded by a ring of dense granular material. On occasion, we observed some sporocysts in direct
contact with host cells. This paper describes the morphology and ultrastructural details of the oocysts, sporocysts and sporozoites
of G. clupearum. This species seems to represent the only coccidium described in fish from this Atlantic coast.
Received: 5 August 2000 / Accepted: 12 October 2000 相似文献
5.
Myxobolus honghuensis n. sp. is described from allogynogenetic gibel carp Carassius auratus gibelio (Bloch), during a survey of myxosporean parasites in Honghu Lake, Hubei Province, China. It is characterized by the presence
of round plasmodia of 5–12 mm in diameter in the pharynx of host. Mature spores of M. honghuensis were pyriform in frontal view and anterior pointed with bluntly round posterior, they measured 16.9 ± 0.5 (15.1–19.5) μm
long, 10.4 ± 0.4 (9.0–11.3) μm wide, and 8.4 ± 0.4 (7.9–9.1) μm thick. Two polar capsules were pyriform and slightly unequal
with larger polar capsule 8.4 ± 0.4 (7.6–10.2) μm × 3.9 ± 0.2 (3.0–4.5) μm and smaller capsule 7.9 ± 0.2 (7.0–9.3) μm × 3.7 ± 0.3
(2.8–4.1) μm. Polar filaments coiled with seven to eight turns. Both morphology and DNA sequence data revealed that M. honghuensis n. sp. was distinct from other described Myxobolus species. Phylogenetic analysis placed M. honghuensis n. sp. in a clade of gill-infecting myxobolids. 相似文献
6.
Propolis (bee glue) is a natural resinous hive product, collected from various plant sources. It has attracted much attention
as a useful substance applied in medicine due to its pharmacological activities. It was aimed to investigate the in vitro
effects of an ethanolic extract of Adana propolis samples on the growth of Leishmania tropica. Parasite cells were treated with five concentrations (25, 50, 100, 50, 500, and 750 μg/ml) of the propolis. The number of
promastigotes in each concentration was calculated using a hemocytometer slide at 24, 48, and 72 h after being harvested.
In the experiments, it was determined that the concentrations up to 100 μg/ml of the propolis did not exhibit antileishmanial
activity against the parasites cells. At these concentrations, there was no changes in terms of morphologically. In addition,
there was no statistically significant difference in terms of cell count between control and these three groups (p > 0.05). However, in culture media containing the propolis samples at 250, 500, and 750-μg/ml concentrations, statistically
significant differences in cell counts were observed, as compared to the control group (p < 0.05). Our results demonstrate that ethanolic extracts of Adana propolis samples reduce the proliferation of L. tropica parasites significantly. 相似文献
7.
Localization and immunogenicity of a low molecular weight antigen of Eimeria tenella 总被引:2,自引:0,他引:2
A low molecular weight (LMW) antigen recognized by a murine monoclonal antibody (C34F1) was localized within endogenous stages of Eimeria tenella (USDA strain 80). Using indirect fluorescent antibody assay and immunoelectron microscopy, the LMW antigen was found in:
sporozoites, first, second and third generation meronts, gamonts, unsporulated oocysts, and sporocysts. The antigen was observed
in the cytoplasm and pellicle of the parasite, and in the parasitophorous vacuole, sporocyst walls and cytoplasm of infected
host cells. The immunogenicity of this LMW antigen was assessed by antigen-specific serum antibody responses in chickens orally
inoculated with live oocysts or injected intramuscularly with dead sporozoites. LMW antigen-specific serum antibodies were
detected using Western blots of E. tenella sporozoites as early as 4 days after sporozoite injection and 6 days after oocyst inoculation. Unusually, the monoclonal
antibody C34F1 reduced the binding of immune chicken serum to the antigen in a competitive antibody binding assay, but not the reverse,
suggesting that there is a single, immunodominant epitope on this antigen. 相似文献
8.
One hundred rock ptarmigans, Lagopus muta islandorum (Faber, 1822), were collected in early October 2006 in northeastern Iceland and examined for coccidian parasites. Two Eimeria species were identified, and each is described as a new species. Sporulated oocysts of one species are ellipsoidal, 24.9 × 16.6
(19.5–30 × 14.5–19) μm. Oocysts have a small micropyle and a two-layered, smooth wall ∼1.0 μm thick. An oocyst residuum is
absent, but one to three polar granules are present. Sporocysts have a rounded end opposite a nipple-like Stieda body and
are 14.3 × 6.3 (12–16.5 × 5.5–7) μm. Sporocysts contain one refractile body and a diffuse granular residuum; the entire contents
of each sporocyst is enclosed by a thin membrane. Sporulated oocysts of the second eimerian are subspherical, 24.7 × 22.2
(20–28 × 18–24.5) μm. The oocysts are without a micropyle but with a two-layered wall, which is ∼1.5 μm thick, with the outer
layer having a rough surface texture. Oocyst residuum is absent, but one to two polar granules are present. Sporocysts have
a rounded end opposite the nipple-like Stieda body atop a prominent sub-Stieda body and are 14.4 × 8.0 (12–15.5 × 6.5–9) μm.
Sporocysts contain a diffuse granular residuum, and each sporozoite has two different-sized refractile bodies. 相似文献
9.
Sakran TF 《Parasitology research》2000,86(9):729-732
Macroscopically visible sarcocysts were observed in the skeletal muscles of naturally infected skinks of the genus Agama (infection rate 11.3%). Sarcocysts were described by means of transmission electron microscopy. These cysts measured 0.03–0.25 × 0.38–1.7 mm
(mean 0.12 × 1.1 mm). Typical mature cysts were bordered by a primary cyst wall that measured 2.4–5.3 μm (mean 3.9 μm) and
was folded into a few nonbranched finger-like protrusions measuring 0.7–1.5 × 1.0–2.5 μm (mean 1.2 × 1.5 μm). These protrusions
contained granular elements, but filaments and tubular elements were not observed. A relatively thick, homogeneous tape was
observed just underneath the primary cyst wall, measuring 0.5–1.0 μm (mean 0.8 μm) and containing a granulated ground substance
in which filaments and tubular elements were not observed. Metrocytes measured 3.1–5.5 × 4.2–7.2 μm (mean 4.0 × 5.8 μm) and
merozoites measured 1.2–3.3 × 4.4–8.6 μm (mean 2.6 × 7.5 μm). The fine ultrastructural characteristics of both metrocytes
and merozoites were similar to those described for many Sarcocystis species and were generally nonspecific.
Received: 21 February 2000 / Accepted: 1 March 2000 相似文献
10.
The uptake of lead by cystacanths of the acanthocephalan Pomphorhynchus laevis in naturally infected amphipods, Gammarus pulex, and by immature parasites in experimentally infected fish, Leuciscus cephalus, was examined following 3-week experimental exposures (0.01 and 0.1 mg l−1 Pb2+). Both G. pulex and the cystacanths of P. laevis accumulated lead but concentrations in the parasites were lower than in the host tissues at the low lead dose and significantly
lower at the high dose. P. laevis from chub exposed to 0.01 mg l−1 lead contained significantly more of the metal than the tissues of their host. Interestingly, there was an increase in the
mean lead levels in the parasites from the control chubs which was concurrent with a decrease in host tissue concentrations.
The results of this experimental study therefore confirm previous suggestions that heavy metals are predominantly accumulated
by acanthocephalans inside the fish definitive host and not by␣cystacanths in the haemocoel of the amphipod intermediate host.
The microhabitat of the parasite is therefore of primary importance rather than its developmental stage. Furthermore, metal
concentrations in adult acanthocephalans will respond rapidly to changes in environmental exposure of their hosts.
Received: 15 November 1997 / Accepted: 11 February 1998 相似文献
11.
Superoxide dismutase (SOD), a cytosolic enzyme that is specific for scavenging superoxide radicals, is involved in protective
mechanism(s) in tissue injury following oxidative processes and phagocytosis. The presence of SOD activity in larval and adult
Trichostrongylus colubriformis, Haemonchus contortus and Ostertagia circumcincta was examined using a xanthine-xanthine oxidase assay and by polyacrylamide gel electrophoresis (PAGE) and non-denaturing
sodium dodecyl sulfate (SDS)-PAGE followed by specific enzyme staining. Total antioxidant status was determined using the
Randox Laboratories kit. The infective larval stages (L3) of the three species contained 8–10 times more activity than the
corresponding adults. SOD activity from adult parasites was sensitive to KCN and SDS and may therefore belong to a Cu/Zn and
Mn class of enzymes. SOD from the larvae was sensitive only to KCN, suggesting that it may belong to a Cu/Zn class of enzymes.
Insignificant interspecies variation was observed when SOD isozyme profiles of larvae were compared. PAGE showed at least
five bands of SOD activity with molecular weights of between 18 and 205 kDa. Examination of total antioxidant status showed
that non-enzymatic antioxidant potential was also present, but only in the infective larvae. The level of antioxidants in
the three genera of larvae studied was similar and amounted to about 0.33–1.07 μM/mg of protein.
Received: 27 January 1998 / Accepted: 26 February 1998 相似文献
12.
A. Giacometti O. Cirioni F. Barchiesi M. Fortuna G. Scalise 《European journal of clinical microbiology & infectious diseases》1999,18(11):827-829
The in vitro activity of ranalexin alone and in combination with other cationic peptides, macrolides, rifampin, and rifabutin
was investigated against a clinical isolate of Cryptosporidium parvum. Susceptibility tests were performed by inoculation of the isolate onto cell monolayers and determining the parasite count
after 48 h of incubation at 37 °C. Antibiotic-free cultures were used as controls in the study. Ranalexin showed low anticryptosporidial
activity: it suppressed the growth of parasites by ≥40% at 50 μM. Ranalexin showed enhanced activity when it was combined
with noninhibitory concentrations of other compounds: a 74.4–94.1% reduction in the number of parasites was observed when
ranalexin 50 μM was combined with magainin II 50 μM, indolicidin 50 μM, clarithromycin 8 mg/l, azithromycin 8 mg/l, rifampin
8 mg/l, and rifabutin 8 mg/l. The results suggest that ranalexin may be effective in inhibiting Cryptosporidium parvum growth in vitro upon combination with other peptides and hydrophobic antibiotics. 相似文献
13.
Henneguya doneci Schulman, 1962 was collected from the gill filaments of Carassius auratus gibelio (Bloch) in Hubei Province, China. The plasmodia located on the surface of the gill arches deformed the neighboring gill filaments.
The size of the plasmodia ranged from 0.6 to 4.5 mm in diameter in different months. The myxospores in the plasmodia measured
10.1 (9.2–11.5) μm long × 8.0 (7.5–8.5) μm wide × 7.5 (7–8) μm thick, with two equal capsules at 4.7 (4–5.5) μm long × 3.3
(2.5–4) μm wide, and two caudal processes 32.7 (24–38.5) μm long, respectively. Polar filaments were coiled 5–6 turns. Ultrastructural
observation of the plasmodia showing the capsulogenesis of H. doneci is described briefly. The external tubule initially invaginated into the polar capsule. The rudimentary polar filaments were
observed to undergo a series of considerable modification, finally developing into mature polar filaments. Molecular analysis
demonstrated that although the myxosporean species were collected from different tissues of hosts in various geographic locations,
they clustered with the Cyprinidae-infecting myxosporean species in the phylogenetic tree. 相似文献
14.
The prevalence and morphology of Blastocystis in fresh faecal material from 227 domestic chickens was investigated. A very high prevalence of infection (approximately
95%) was found in chickens from four of the five commercial farms studied. Extremely high numbers of Blastocystis were found in the majority of samples. Blastocystis cells showed considerable variation in size, ranging from approx. 3 μm to approx. 120 μm in diameter. This size range is
more extreme than those previously recognised for the organism from chickens. All chickens from one farm appeared free of
Blastocystis infection. Most Blastocystis cells appeared to be the vacuolar form, although the shape of the cells and the appearance of the central vacuole contents
varied considerably within and among faecal samples. Nuclei showed “spots” of electron-opaque material, generally arranged
as a band within the nuclei. Multiple individual cysts within a single outer fibrillar layer were found in addition to single
cysts without an encompassing fibrillar layer.
Received: 10 June 1998 / Accepted: 4 July 1998 相似文献
15.
Fifty-seven Hirundo rubicola savignii swallows were collected from Damietta, Tanta, Dakahlyia and Sharkia Provinces, Egypt. They were examined for coccidian parasites.
The percentage of infection with Isospora stages was 12.3%. After diagnosis it was noted that the parasites belong to a new species. The unsporulated oocysts were
spherical, measuring 25.7–31.9 μm in diameter with a mean of 28.3 μm. A micropyle, polar granule and oocyst residuum were
absent. Sporocysts appeared lemon-shaped and measured 19.6–24.5 μm × 12.5–17.5 μm with a mean of 22.9 × 14.4 μm. Stieda body
and the sporocyst's residual body were clearly visible. Sporozoites measured 11–14.2 × 4.4–5.1 μm with a mean of 11.4 × 4.7 μm.
Sporulation time was 72 h at room temperature (25 °C). Endogenous stages including schizogony and gamogony were detected in
epithelial cells of the duodenum, jejunum and ileum of the host. Schizogony consisted of two generations. Mature first generation
schizonts reached up to 11 μm in diameter and produced merozoites measuring 3.5 × 1.7 μm. Mature second generation schizonts
measured 17.2 × 12.3 μm and produced merozoites measuring 11.8 × 2.2 μm. Gamogonic stages were differentiated into microgamonts
and macrogamonts. Mature microgamonts were spherical and measured 23.2 μm in diameter, producing curved microgametes measuring
4.5 × 0.7 μm. The ovoid macrogametes measured 19.6 × 14.7 μm and were characterized by a large nucleus and nucleolus. Early,
more or less spherical, oocysts were detected inside the intestinal epithelial cells and in the intestinal lumen. They measured
19.6 μm in diameter. The sporont measured 17.2 μm in diameter. Cytochemical studies on schizogony, gamogony and oocysts were
accomplished and showed distribution of polysaccharides and composition of the oocyst wall.
Received: 15 May 1999 / Accepted: 25 June 1999 相似文献
16.
Tritrichomonas suis and T. foetus are characterized herein at the ultrastructural and biochemical levels. Microcinematography and measurements, scanning and
transmission electron microscopy, cytochemistry for carbohydrate detection (Thiéry technique), and isozyme electrophoresis
analysis were performed. In all, 11 different strains from 5 species of parasites were studied (T. foetus, T. suis, Trichomonas gallinae, T. vaginalis, and Monocercomonas sp.). A total of 11 enzymes were scored. Fine-structure study using scanning and transmission electron microscopy demonstrated
that T.␣suis and T. foetus are identical morphologically. The high degree of isozymatic similarity noted between T.␣suis and T. foetus is consistent with the hypothesis that they may be different strains of the same species.
Received: 13 July 1996 / Accepted: 20 August 1996 相似文献
17.
Marise M. O. Cabral Patrícia Azambuja Otto R. Gottlieb Eloi S. Garcia 《Parasitology research》1999,85(3):184-187
Two neolignans, burchellin and nordihydroguaiaretic acid (NDGA), were toxic only to Trypanosoma cruzi clone Dm28c maintained in brain heart infusion (BHI) medium at a concentration of 100 μg/ml, not 10 μg/ml. When Rhodnius prolixus was fed with epimastigotes of T. cruzi and treated simultaneously with a single dose of burchellin or NDGA at 10 μg/ml of blood meal the number of parasites in
the gut decreased. Whereas burchellin was only partially active, NDGA drastically reduced the number of epimastigotes and
metacyclic trypomastigotes of T. cruzi in the excreta (urine plus feces). When the insect larvae were pretreated with burchellin or NDGA at 20 days before the infection
with T. cruzi a significant reduction in the number of parasites in the gut occurred. However, when both compounds were applied at 20 days
after the establishment of T. cruzi infection, although burchellin significantly reduced the gut infection, neither compound could abolish the infection entirely
within the subsequent 15 days.
Received: 15 June 1998 / Accepted: 15 August 1998 相似文献
18.
For decades, drug resistance has been the major obstacle in the fight against malaria, and the search for new drugs together
with the combination therapy constitutes the major approach in responding to this situation. The present study aims at assessing
the in vitro antimalarial activity of four compounds isolated from Kigelia africana stem bark (atranorin - KAE1, specicoside - KAE7, 2β,3β,19α-trihydroxy-urs-12-20-en-28-oic acid – KAE3, and p-hydroxy-cinnamic acid – KAE10) and their drug interactions among themselves and their combination effects with quinine and
artemether. The antiplasmodial activity and drug interactions were evaluated against the multidrug-resistant W2mef strain
of Plasmodium falciparum using the parasite lactate dehydrogenase assay. Three of the four compounds tested were significantly active against W2mef:
specicoside (IC50 = 1.02 ± 0.17 μM), 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid (IC50 = 1.86 ± 0.15 μM) and atranorin (IC50 = 1.78 ± 0.18 μM), whereas p-hydroxy-cinnamic acid showed a weak activity (IC50 = 12.89 ± 0.87 μM). A slight synergistic effect was observed between atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic
acid (Combination index, CI = 0.82) whereas the interaction between specicoside and p-hydroxy-cinnamic acid were instead antagonistic (CI = 2.67). All the three compounds showed synergistic effects with artemether,
unlike the slight antagonistic interactions of atranorin and 2β,3β,19α-trihydroxy-urs-12-en-28-oic acid in combination with
quinine. K. africana compounds are therefore likely to serve as leads in the development of new partner drugs in artemether-based combination
therapy. 相似文献
19.
Passero LF Tomokane TY Corbett CE Laurenti MD Toyama MH 《Parasitology research》2007,101(5):1365-1371
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 μg/ml) in comparison
with that of Cdca venom (IC50 value of 9.41 ± 1.21 μg/ml), while Cdcol venom increased parasite numbers in 50% at a concentration of 44.30 ± 2.18 μg/ml. In addition, this venom showed a low anti-leishmanial
activity in higher concentrations (IC50 value of 281.00 ± 9.50 μg/ml). The main fractions of Cdca venom were isolated and assayed under similar conditions used for assessing crude venom. The most active fractions were gyroxin
and crotamine that had IC50 values of 3.80 ± 0.52 μg/ml and 19.95 ± 4.21 μg/ml, respectively. Convulxin also inhibited parasite
growth rate, although this effect was not dose-dependent. Crotoxin was the least effective fraction with an IC50 value of
99.80 ± 2.21 μg/ml. None of the protein fractions presented cytotoxic effects against J774 cells in culture. In vivo assays
using BALB/c mice revealed that crotoxin and crotamine were the main toxic fractions. In conclusion, C. durissus cascavella venom has three main fractions with anti-leishmanial activity. These results open new possibilities to find proteins that
might be used as possible agents against cutaneous leishmaniasis. 相似文献
20.
Abdel-Ghaffar F Bashtar AR Morsy K Mehlhorn H Al Quraishy S Al-Rasheid K Abdel-Gaber R 《Parasitology research》2012,110(2):741-752
One hundred three out of 225 (45.8%) of the Red Sea fish Saurida tumbil were infected with microsporidian parasites. The infection was recorded as tumor-like masses (whitish macroscopic cysts)
or xenomas often up to 2 cm in diameter and embedded in the peritoneal cavity. Generally, the infection was increased during
winter 63.8% (86 out of 135) and fall to 18.9% (17 out of 90) in summer. Light microscopic study revealed that xenomas were
encapsulated by a fibrous layer encircling numerous sporophorous vesicles filled with mature spores measuring 1.7 ± 0.6 (1.5–2.7 μm) × 1.5 ± 0.3 μm
(1.2–1.8 μm) in size. Ultrastructural microscopic study showed the presence of smooth membranes of the sarcoplasmic reticulum
forming a thick, amorphous coat surrounding various developmental stages of the parasite. The various recognizable stages
of the parasite were uninuclear, binucleated, and multinucleated meronts followed by detachment of the plasmalemma of the
sporont from the sporophorous vesicle producing sporoblasts. Mature spores consist of a spore coat and spore contents. The
spore contents consist of the uninucleated sporoplasm and a posterior vacuole located at the posterior end. The polar tube
consists of a straight shaft and a coiled region (26–32 coils) arranged in many rows along the inside periphery of the spore.
The polaroplast consisted of an anterior region of closely and loosely packed membranes. Molecular analysis based on the small
subunit rDNA gene was performed to determine the phylogenetic position of the present species. The percentage identity between
this species and a range of other microsporidia predominantly from aquatic hosts demonstrated a high degree of similarity
(>92%) with eight Pleistophora species. Comparison of the nucleotide sequences and divergence showed that the sequence of the present microsporidium was
most similar to that of Pleistophora anguillarum (99.8% identity) differing in 13 nucleotide positions. So, the present species was recorded and phylogenetically positioned
as a new species of Pleistophora. 相似文献