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At least 217 records · Page 12Linked to original sources
PubMed1996

Therapeutic efficacy of halofuginone and spiramycin treatment against Cryptosporidium serpentis (Apicomplexa: Cryptosporidiidae) infections in captive snakes.

The therapeutic effect of halofuginone hydrobromide (Steronol) and spiramycin solubilized (Spirasol) applied to clinical Cryptosporidium serpentis infections in captive snakes was investigated. Pathological changes induced by C. serpentis were typical for snake cryptosporidiosis. Spiramycin induced no significant change in the pattern of shedding of fecal Cryptosporidium oocysts; biopsies and necropsies revealed cryptosporidiosis in gastric mucosa of all spiramycin-treated animals. In all, 8 of 21 (38%) halofuginone-treated snakes stopped shedding C. serpentis oocysts; examination of gastric tissue of 6 of these 8 animals revealed cryptosporidiosis in 2 snakes. Hepatotoxic and nephrotoxic pathological changes induced by halofuginone included focal or multifocal, severe, acute liver necrosis; severe liver hemosiderosis; and bilateral, severe, acute diffuse cortical and tubular necrosis and iron deposition. Postprandial regurgitation associated with midbody swelling, observed in 4 halofuginone-treated and 2 spiramycin-treated snakes at 15 and 21 weeks after drug withdrawal, did not coincide with oocyst-positive feces. Neither halofuginone nor spiramycin treatment produced a satisfactory therapeutic outcome when applied against clinical C. serpentis infections in snakes.

Animals↗
PubMed1996

Characterization of genomic clones encoding two microneme antigens of Sarcocystis muris (Apicomplexa).

Subgenomic libraries were constructed from Sarcocystis muris total DNA. Hybridization screening with a microneme-specific cDNA probe resulted in two clones that were sequenced. The amino acid sequences deduced showed 87% homology among each other. Three different domains were recognized within both polypeptides. Domain I includes the putative N-terminal signal sequence. Domain II represents a strongly hydrophilic region, entirely homologous in the two genes. Domain III encodes the mature polypeptides with theoretical molecular masses of 15.1 kDa each. Among 28 amino acid changes in this region, 19 replacements are conservative. The putative polypeptides carried 12 conserved cysteine residues and showed homologies with plasma kallikrein, factor XI, and an antigen of Eimeria tenella. The recombinant proteins are recognized by the monoclonal antibody 3A8 directed against the 16/17-kDa microneme antigen of S. muris cystozoites. Antiserum raised against one of the purified fusion proteins cross-reacts with its counterpart and with the native 16/17-kDa band-doublet.

Amino Acid Sequence↗
PubMed1996

Light microscopic description of Eimeria sparis sp. nov. and Goussia sparis sp. nov. (Protozoa:Apicomplexa) from Sparus aurata L. (Pisces: Teleostei).

Two new species of Coccidia, Eimeria sparis sp. nov. and Goussia sparis sp. nov., were found in the intestine of Sparus aurata from different culture systems of Spain. These are the first coccidian species described from this host. E. sparis is distinguished from other Eimeria spp. from Perciformes in the size and shape of the sporocysts, which measure 6-9.7 (mean = 7.78, SD = 1.33) x4-6.5 (5.3 +/- 0.92) microns, and in the Stieda-like body. Mature oocysts, spherical or subspherical, measure 9.4-14.3 (11.88 +/- 1.85) microns. G. sparis differs from other Goussia spp. from fish of the Mediterranean area in the size and shape of the oocysts and sporocysts as well as in the location. Mature oocysts measure 16-21 (17.4 +/- 1.5) x 13-18 (14.4 +/- 1.7) microns and sporocysts, 8.6-10.3 (9.5 +/- 0.5) x 5.7-7.4 (mean 6.5 +/- 0.5) microns. The different stages of merogony, gamogony, and sporogony of both species were examined at the light-microscope level in fresh material and histology specimens. Sporulation was endogenous in E. sparis and exogenous in G. sparis.

Animals↗
PubMed1997

Ultrastructure and cytochemistry study of Eimeria sparis (Protozoa:Apicomplexa) stages from the intestine of gilthead sea bream Sparus aurata L. (Pisces:teleostei).

The ultrastructure and cytochemistry of merogonial, gamogonial, and early sporogonial stages of Eimeria sparis in the intestine of Sparus aurata were studied. Mature stages showed the typical pellicle, which was lost in some transitional stages. An apparent unit membrane was seen in some immature stages. A parasitophorous vacuole, sometimes with membrane vesicular invaginations, was usually observed. We propose that the stages located over the epithelium and the so-called epicellular stages be termed supraepithelial stages. Endomerogony was observed in intraepithelial and supraepithelial positions. Intraepithelial stages apparently starting ectomerogony were also detected. Electron-dense granules similar to wall-forming-like bodies of types 1 and 2 were observed. Microgametes exhibited two flagella. Cytochemistry study revealed scarce polysaccharides, if any, in merogonial stages and in microgamonts. The occurrence of polysaccharides and amylopectin granules increased progressively in macrogamonts, macrogametes, zygotes, and early oocysts. Lipidic droplets were scarce of absent in merogonial stages and abundant in maturing macrogamonts. Some glycoproteins were demonstrated in certain merogonial stages.

Animals↗
PubMed1997

Diffusion of microinjected markers across the parasitophorous vacuole membrane in cells infected with Eimeria nieschulzi (Coccidia, Apicomplexa).

Cells infected with the intracellular parasite Eimeria nieschulzi were microinjected with lucifer yellow (457 Da), biocytin lucifer yellow (850 Da) and dextranrhodamine (10,000 Da). Immediately after injection of a mixture of the markers into the host cell cytoplasm, a differential diffusion pattern was observed in trophozoites and schizonts. Lucifer yellow and biotin lucifer yellow were seen to enter the parasitophorous vacuole, whereas the dextran was excluded. Since these markers cannot permeate cell membranes, this suggests that the Eimerian parasitophorous vacuole acts as a molecular sieve. This method allows the visualization and further characterization of the parasitophorous vacuole in living cells.

Animals↗
PubMed1998

Isolation and characterization of cDNA clones encoding a 32-kDa dense-granule antigen of Sarcocystis muris (Apicomplexa).

A monoclonal antibody (2F4) directed against a 32-kDa dense-granule antigen of Sarcocystis muris cyst merozoites (bradyzoites) was used to screen a lambda ZAP cDNA expression library. A clone with an insert of 1.4 kb in length (DG 32/1) was isolated. A fusion protein derived from bacteria harbouring the recombinant plasmid DG 32/1 reacted with monoclonal antibody (mAb) 2F4. Southern blot hybridization suggests that the gene is present as a single copy. On Northern blots, a single mRNA species of 1.8 kb was detected by a cDNA-derived probe. In addition, we isolated a full-length clone (DG 32/PH1) by screening the cDNA library with a non-radioactive-labelled cDNA probe. The nucleotide sequence of DG 32/PH1 comprises 1.57 kb. It contains an open reading frame of 882 bp with a coding capacity of approximately 32 kDa. The hypothetical polypeptide consists of a putative N-terminal signal peptide and the mature protein sequence. The occurrence of an N-terminal signal sequence is consistent with the observation that the 32-kDa protein of S. muris is secreted from the dense granules.

Amino Acid Sequence↗
PubMed1999

Isolation and characterization of a cDNA clone encoding a thiol proteinase of Sarcocystis muris cyst mero' zoites (Apicomplexa).

A cDNA library of Sarcocystis muris cyst merozoites was screened using a digoxigenin-labeled probe. This probe was derived from a 504-bp polymerase-chain-reaction fragment representing part of a thiol proteinase. Several cDNA clones were isolated, one of which (PH08) consists of a nucleotide sequence of 1694 bp and encodes the complete prepropolypeptide of a cathepsin L-like proteinase. PH08 contains an open reading frame of 394 amino acid (aa) residues with a 46-residue signal sequence, which is followed by a 129-residue propeptide and 219 aa residues of the mature enzyme. Two potential glycosylation sites and a putative polyadenylation signal were also identified. The occurrence of the highly conserved interspersed ERFNIN aa motif, not found in cathepsin B-like proteinases, suggests the classification of the enzyme as a cathepsin L-like proteinase. Results worked out in this study will enable production of the recombinant thiol proteinase of S. muris cyst merozoites necessary for study of the substrate specificity as well as other biochemical parameters of this enzyme.

Amino Acid Sequence↗
PubMed1999

Taxonomy and phylogeny of some Eimeria (Apicomplexa:Eimeriidae) species of rodents as determined by polymerase chain reaction/restriction-fragment-length polymorphism analysis of 18S rDNA.

The 18S rDNA genes of 10 Eimeria species from rodents (E. albigulae, E. arizonensis, E. falciformis, E. langebarteli, E. nieschulzi, E. onychomysis, E. papillata, E. reedi, E. separata, E. sevilletensis) were polymerase-chain-reaction (PCR)-amplified, digested with 12 restriction endonucleases, and electophoresed in agarose gels. The resulting fragment patterns (riboprints) distinguished all species except E. sevilletensis from E. falciformis, and E. arizonensis from E. albigulae; the sporulated oocysts of the latter two species and of E. onychomysis are often indistinguishable morphologically. When the restriction fragment data were analyzed using distance and parsimony phylogenetic methods a clade was found consistently, which contained E. arizonensis, E. albigulae, E. onychomysis, E. reedi, and E. papillata. This finding and other results of the phylogenetic analyses agreed and supplemented previous phylogenetic work on the Eimeria of rodents. Riboprinting appears to provide useful data for taxonomic and phylogenetic studies on the genus Eimeria and may be especially practical when samples do not contain enough oocysts for other molecular-based methods.

Animals↗
PubMed1999

Characterization of a genomic region encoding the 32-kDa dense granule antigen of Sarcocystis muris (Apicomplexa).

Two subgenomic libraries constructed from Sarcocystis muris total DNA were screened with a cDNA probe, specific for a 32-kDa protein associated with the dense granules. Two clones reacted positively and were isolated, gDG 32/1 and gDG 32/2. Genomic clone gDG32/1 and part of clone gDG 32/2 have been sequenced. The composite nucleotide sequence of these genomic clones comprises 4.34 kb. It contains a 5' region of 2.14 kb, a first coding region (222 bp, exon I), a noncoding region (608 bp, intron), a second coding region (660 bp, exon II), and a 3' region of 693 bp. The upstream region shows a eukaryotic promoter structure and a consensus sequence for the 5' and 3' splicing sites. Thus the open reading frame (ORF DG32) coding for the 32-kDa protein of the dense granules of S. muris cyst merozoites is interrupted by an intron. To our knowledge, dg32 is the first sarcosporidian mosaic gene to be characterized.

Amino Acid Sequence↗
PubMed2005

Phylogenetic congruence of Sarcocystis neurona Dubey et al., 1991 (Apicomplexa: Sarcocystidae) in the United States based on sequence analysis and restriction fragment length polymorphism (RFLP).

The objectives of the present study were to assess the genetic diversity, phylogeny and phylogeographical relationships of available Sarcocystis neurona isolates from different localities in the United States. All 13 Sarcocystis isolates from different hosts were subjected to polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analyses using two published DNA markers (25/396 and 33/54). The 334 bp sequence of the 25/396 marker of these isolates and Besnoitia darlingi, B. bennetti, Toxoplasma gondii and Neospora caninum were sequenced and compared. Phylogenetic analysis was performed using neighbour-joining (NJ), maximum parsimony (MP) and minimum evolution (ME) methods based on the sequences of the 25/396 marker of the 13 Sarcocystis isolates obtained in this study and sequences of 10 related isolates from GenBank. Phylogenetic trees revealed a close relatedness among S. neurona isolates in the US (nucleotide sequence diversity <5.0%). US isolates formed a monophyletic group and appeared more closely related to each other than to the South American isolates, which formed a separate lineage. NJ and ME trees with Kimura 2-parameter model separated S. neurona into two separate groups: a northern US group and a Southern US group. These findings suggest a correlation between grouping of the isolates and geographical segregation and were consistent with a genetic bottleneck hypothesis during opossum colonisation of North America. These data do not support either the view of S. neurona as a single super-species or its division into multiple subspecies.

Animals↗
PubMed2006

Seven new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from colubrid snakes of Guatemala and a discussion of what to call ellipsoid tetrasporocystic, dizoic coccidia of reptiles.

During a survey of Guatemalan herpetofauna in the summers of 1998-2000, 29 presumed new species of Eimeria Schneider, 1875 were found, seven of which have a distinct elongate-ellipsoidal shape (L/W ratio >or= 1.7) and are described herein. Six of the seven new species are similar in oöcyst length, width and L/W ratio and sporocyst length, width and L/W ratio, lack a micropyle, oöcyst residuum, Stieda body, sub-- and parastieda bodies, have a polar granule and sporocyst residuum, and their sporocysts appear to have dehiscence sutures. The seventh is slightly smaller and has sporocysts with a Stieda body. The new species are: E. coniophanes n. sp - whose sporulated oöcysts from Coniophanes fissidens are 29.2x14.9 (27-31x13-16) microm, with sporocysts 10.0 x 7.8 microm; E. coniophis n. sp. -from Conophis lineatus are 32.0x16.5 (30-34x14-18) microm, with sporocysts 10.2 x 8.9microm; E. dryomarchoni n. sp. - from Drymarchon corais are 32.2x17.7 (31-34x17-19) microm, with sporocysts 10.7 x 8.6 microm; E. leptophis n. sp. - from Leptophis mexicanus are 29.5x17.0 (28-31x16-18) microm, with sporocysts 10.0 x 9.1 microm; E. oxybelis n. sp. - from Oxybelis aeneus are 31.8x16.5 (29-33x15-18) microm, with sporocysts 10.3 x 8.8 microm; and E. scaphiodontophis n. sp. - from Scaphiodontophis annulatus are 30.0x15.3 (28-33x14-16) microm, with sporocysts 9.9 x 7.9 microm. Sporulated oöcysts of E. siboni n. sp. from Sibon nebulata are 24.3x14.2 (21-27x13-16) microm, with sporocysts 10.0 x 7.1 microm and with a Stieda body. We conclude that until all aspects of each life-cycle are known, it is prudent at this time to name all tetrasporocystic dizoic coccidia from snakes as members of Eimeria rather than place some of them in Choleoeimeria Paperna & Landsberg, 1989.

Animals↗
PubMed2006

Leucocytozoon atkinsoni n. sp. (Apicomplexa: Leucocytozoidae) from the avian family Timaliidae.

Investigators of haematozoa of the Timaliidae have reported the presence of two species of Leucocytozoon Berestneff, 1904, i.e. L. liothricis Laveran & Marullaz, 1914 and L. timaliae Bennett, Earlé & Pierce, 1993. Blood films collected from 42 wild-caught babblers in Madagascar were stained and examined for the presence of haematozoa using a compound microscope. To date, no species of avian haematozoa have been reported from babblers in Madagascar, although haematozoa have been observed. In the present study, we report a new species of Leucocytozoon, L. atkinsoni n. sp., whose morphometrics fall between those reported for the two previously described species from timaliids. The parasite is capped by the host cell nucleus covering 38% of its perimeter. L. atkinsoni n. sp. was found to have a marked, intensely staining, nucleolus as well as vacuoles in the parasite cytoplasm, in contrast to both L. liothricis and L. timaliae. Remnants of the host cell cytoplasm are commonly observed in cells infected with L. atkinsoni, a characteristic not reported in association with either of the previously described species from these hosts.

Animals↗
PubMed2006

Eimeria lokuma n. sp. (Apicomplexa: Eimeriidae), a new coccidium from the African helmeted turtle Pelomedusa subrufa (Lacépède) (Testudines: Pelomedusidae).

Coprological examination of nine African helmeted turtles Pelomedusa subrufa from Kenya revealed the presence of a new coccidium belonging to Eimeria Schneider, 1875. Oöcysts of Eimeria lokuma n. sp. are spherical to sub-spherical, 13.6 (13-14.5) x 13 (12-14) microm, lack a micropyle and a polar granule, but possess a granular oöcyst residuum. The sporocysts are elongate, oval to spindle-shaped and 8.3 (7.5-9.5) x 4.4 (4-5) microm. The Stieda body is relatively low, flat and wide, and covered with a membranous, highly flexible, scarf-like structure which protrudes from its strengthened margins. The sporozoites possess two refractile bodies. Based on the presence of a Stieda body, the described species is classified as Eimeria (sensu stricto).

Animals↗
PubMed1984

Effects of decoquinate and clopidol on electron transport in mitochondria of Eimeria tenella (Apicomplexa: Coccidia).

Resistance of the chicken coccidium Eimeria tenella to the anticoccidial agents decoquinate and clopidol, and the synergistic activity of mixtures of these compounds have been confirmed in vivo. Inhibition of electron transport by decoquinate and clopidol has been studied in mitochondria isolated from unsporulated oocysts of the same lines of E. tenella as those used in the in vivo studies. Electron transport in mitochondria of a drug sensitive line was susceptible to inhibition by both decoquinate and clopidol, and mitochondria isolated from lines made resistant to one or the other of these compounds showed a corresponding resistance at the level of electron transport. Combinations of low concentrations of decoquinate and clopidol caused a greater inhibition of electron transport than expected from summation of their individual actions. Isobolograms showed that decoquinate and clopidol in fact potentiated each other's effect on electron transport. Induced resistance to either decoquinate or clopidol resulted in an increased sensitivity of electron transport to inhibition by the other drug. Cytochrome spectra of E. tenella mitochondria and a biphasic response of NADH-oxidase and terminal oxidase activity to inhibition by cyanide or azide suggest the presence of two functional terminal oxidases. There is a correlation between the resistance of electron transport to inhibition by decoquinate or clopidol and the susceptibility to inhibition by cyanide or azide. Mitochondrial electron transport that is more resistant to inhibition by decoquinate exhibits greater sensitivity to cyanide and azide; electron transport that is more resistant to inhibition by clopidol exhibits a decreased sensitivity to cyanide and azide. Resistance to decoquinate and clopidol is discussed in view of a possibly branched electron transport chain in mitochondria of E. tenella.

Animals↗
PubMed1984

Potent and selective hydroxynaphthoquinone inhibitors of mitochondrial electron transport in Eimeria tenella (Apicomplexa: Coccidia).

Novel hydroxynaphthoquinones have been shown to be potent and selective inhibitors of mitochondrial electron transport in the protozoan Eimeria tenella, inhibiting at concentrations of 10(-10) to 10(-11)M. The primary site of electron transport inhibition has been localized to the ubiquinol-cytochrome c reductase span of the respiratory chain, whereas a secondary site of inhibition occurs in the NADH- and succinate-ubiquinone reductase complexes. Inhibition at the primary site is selective for the E. tenella enzyme; inhibition at the secondary sites is comparable in both E. tenella and chick (Gallus gallus) liver mitochondria. Hydroxynaphthoquinone inhibition of chick liver succinate-cyto-chrome c reductase was fully reversible by addition of the exogenous ubiquinone-2 analogue, 6-decyl-2,3-dimethoxy-5-methyl-1,4-benzoquinone; inhibition of the corresponding E. tenella enzyme was not reversed by this ubiquinone. E. tenella lines made resistant to the anticoccidial agents decoquinate or clopidol showed no cross-resistance to the hydroxynaphthoquinones, either at the level of electron transport or in vivo.

Coccidiostats↗
PubMed1992

Sarcocystis muris (Apicomplexa): a thiol protease from the dense granules.

Homogenates of Sarcocystis muris merozoites (cyst form) and the subcellular fraction of dense granules were assayed for protease activity with substrate-impregnated SDS-polyacrylamide gels. Four acidic and several basic proteases were detected in the merozoites. One of the basic proteases was further characterized as a thiol protease (EC 3.4.22). The activity of this protease was enriched in the dense granule fraction.

Animals↗