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At least 127 records · Page 7Linked to original sources
PubMed2003

A survey of coccidian infections of freshwater fishes of Peninsular Malaysia, with descriptions of three species of Goussia Labbé, 1896 (Apicomplexa: Eimeriidae).

Ninety-five specimens of 14 freshwater fish species from small streams in the Kuala Terengganu district and the Lake Kenyir Reservoir, Malaysia, were surveyed for coccidian infections. Six fish species proved to be infected with apicomplexans belonging to the genus Goussia. In all of these fishes Goussia species were found in unsporulated and semisporulated stages. Oöcysts of four species inhabiting the intestinal epithelium became sporulated in tap-water within 24 hours. In two fish species sporulation failed and only unsporulated oöcysts were recorded in the intestine. Three of the intestinal species finishing sporulation proved to be new to science and were described as Goussia malayensis n. sp., G. bettae n. sp. and G. pogonognathi n. sp. from Apocheilus panchax, Betta splendens and Hemirhamphodon pogonognatus, respectively. The fourth species, found in Trichogaster pectoralis, was identified as G. trichogasteri Székely & Molnár, 1992, a species known from aquarium-cultured T. trichopterus.

Animals↗
PubMed2001

Pterospora floridiensis, a new species of acephaline gregarine (Apicomplexa) from the maldanid polychaete Axiothella mucosa in St. Andrew Bay, Florida.

Pterospora floridiensis, a new species of acephaline gregarine from the body cavity of the bamboo worm Axiothella mucosa (Polychaeta: Maldanidae), is described. The gamont stage is distinctive and possesses a central cytoplasmic mass and two elongate trunks that bifurcate repeatedly and comprise approximately 60% of the total cell length. The gamont averages 198 (50-545) x 71 (25-180) microm (N= 45, 43) from the tip of the trunks to the anterior (the junctional site with the other gamont in syzygy). Gametocysts average 402 (297-545) x 304 (149-495) microm (N = 37). The oöcysts measure 22.5 (20.5-23.5) x 8.3 (7.0-10.0) microm (N = 30) and possess an internal capsule (average length = 13.9 microm, N = 30) containing the sporozoites and aliform wings on the epispore.

Animals↗
PubMed1984

Occurrence of Leucocytozoon and Haemoproteus (Apicomplexa, Haemosporina) in Falconiformes and Strigiformes of Italy.

Blood smears from Falconiformes (91 birds of 10 species) and Strigiformes (23 birds of 5 species) captured in Italy, were examined for haematozoa. Leucocytozoon were found in Falco tinnuculus, Buteo buteo, Circus cyaneus, Circus pygargus, Accipiter nisus from Falconiformes and in Strix aluco, from Strigiformes. Haemoproteus were found in Falco tinnuculus and Strix aluco; this latter species harbored mixed infections Leucocytozoon-Haemoproteus. Prevalences were 20.80% in Falconiformes and 21.74% in Strigiformes.

Animals↗
PubMed1995

Parasitism of Aedes aegypti and Ae. albopictus (Diptera: Culicidae) by Ascogregarina spp. (Apicomplexa: Lecudinidae) in Florida.

Aedes aegypti (L.) and Ae. albopictus (Skuse) from 40 sites in 17 counties of Florida were surveyed for gregarine parasites during the spring and autumn of 1993 and in July 1994. Larvae collected from containers (mainly tires) were dissected to determine the number of gregarine trophozoites present. Ascogregarina spp. were found at 70% of the sites and occurred as frequently in Ae. aegypti populations as in Ae. albopictus. Within sites, parasite distributions were highly variable and aggregated in host populations. Parasite loads ranged from 1 to 486 trophozoites per host. Mean parasite load was significantly higher in Ae. aegypti larvae (52.5 per host) than in Ae. albopictus (33.5 per host). Parasite prevalence was significantly higher in Ae. aegypti populations that were not sympatric with Ae. albopictus compared with allopatric Ae. albopictus or sympatric populations of either species. In sympatric populations, Ae. aegypti tended to have equal or higher parasite prevalence than the cohabiting Ae. albopictus. Ascogregarina taiwanensis (Lien & Levine) prevalence in Ae. albopictus was significantly higher in areas where these hosts have been present for at least 3 yr. These data contribute to the hypothesis that parasite-mediated competition may be a factor in the apparent displacement of Ae. aegypti by Ae. albopictus in Florida.

Aedes↗
PubMed1996

Developmental synchrony of Ascogregarina taiwanensis (Apicomplexa: Lecudinidae) within Aedes albopictus (Diptera: Cuclicidae).

Development of Ascogregarina taiwanensis Lien & Levine was synchronized with its host, the Asian tiger mosquito, Aedes albopictus (Skuse). Trophozoites of the parasite migrate to the Malpighian tubules where the gamonts fuse to form gametocysts and later mature oocysts. In this study, we observed that water temperature, which alters the development time of mosquito larvae, also affected parasite development. A. taiwanensis developed in a shorter time at 29 degrees C, whereas at 14 degrees C, the development was extended to as long as 17 d. Few mature oocysts were produced at 29 degrees C, although gametocysts occasionally were found in the lumen of Malpighian tubules. In contrast, gametocysts did not develop at 14 degrees C unless pupation occurred. Stage transformation of the parasite was determined by the metamorphosis of the mosquito host. Gametocyst formation occurred earlier when infected larvae were injected with an appropriate concentration of 20-hydroxyecdysone, indicating this molting hormone was involved in regulating the synchronous development of A. taiwanensis in its mosquito host.

Aedes↗
PubMed1999

Effect of nutrient levels and Ascogregarina taiwanensis (Apicomplexa: Lecudinidae) infections on the vector competence of Aedes albopictus (Diptera: Culicidae) for Dirofilaria immitis (Filarioidea: Onchocercidae).

The effect of habitat nutrients and Ascogregarina taiwanensis (Lein & Levine) infection on the vector competence of a New Orleans strain of Aedes albopictus (Skuse) for Dirofilaria immitis (Leidy) were evaluated. Larvae were infected with A. taiwanensis oocysts and reared under high and deficient nutrient conditions using leaf litter as a food source. Ascogregarine-infected and uninfected females were fed on D. immitis-infected blood and examined after 15 d for filariae. Susceptibility to infection with filaria was 60-70% for all females. In groups reared under high nutrients, the infective rate (3rd-stage larvae present) of coinfected females (18%) was significantly greater than females infected only with heartworm (6%). Host mortality following blood meals was significantly less in coinfected (22%) than in heartworm-infected females (37%). Under deficient nutrient conditions, there was no significant difference between the infective rate (8%) or post-blood meal mortality (5%) of coinfected females compared with heartworm-infected females. Prevalence of melanization reactions in coinfected females was significantly higher (31%) than in females infected only with heartworm (6%) at both nutrient levels. It is concluded that high nutrient levels and ascogregarine infection increase the vector competence of Ae. albopictus for D. immitis by enhancing the immune response so that fewer filariae develop, causing lower host mortality. Under low nutrient conditions, the smaller host contains less food reserves for filariae development, and in coinfected females melanization reactions and damage to the Malpighian tubules may reduce vector survival.

Aedes↗
PubMed2005

Discovery of the principal specific transcription factors of Apicomplexa and their implication for the evolution of the AP2-integrase DNA binding domains.

The comparative genomics of apicomplexans, such as the malarial parasite Plasmodium, the cattle parasite Theileria and the emerging human parasite Cryptosporidium, have suggested an unexpected paucity of specific transcription factors (TFs) with DNA binding domains that are closely related to those found in the major families of TFs from other eukaryotes. This apparent lack of specific TFs is paradoxical, given that the apicomplexans show a complex developmental cycle in one or more hosts and a reproducible pattern of differential gene expression in course of this cycle. Using sensitive sequence profile searches, we show that the apicomplexans possess a lineage-specific expansion of a novel family of proteins with a version of the AP2 (Apetala2)-integrase DNA binding domain, which is present in numerous plant TFs. About 20-27 members of this apicomplexan AP2 (ApiAP2) family are encoded in different apicomplexan genomes, with each protein containing one to four copies of the AP2 DNA binding domain. Using gene expression data from Plasmodium falciparum, we show that guilds of ApiAP2 genes are expressed in different stages of intraerythrocytic development. By analogy to the plant AP2 proteins and based on the expression patterns, we predict that the ApiAP2 proteins are likely to function as previously unknown specific TFs in the apicomplexans and regulate the progression of their developmental cycle. In addition to the ApiAP2 family, we also identified two other novel families of AP2 DNA binding domains in bacteria and transposons. Using structure similarity searches, we also identified divergent versions of the AP2-integrase DNA binding domain fold in the DNA binding region of the PI-SceI homing endonuclease and the C-terminal domain of the pleckstrin homology (PH) domain-like modules of eukaryotes. Integrating these findings, we present a reconstruction of the evolutionary scenario of the AP2-integrase DNA binding domain fold, which suggests that it underwent multiple independent combinations with different types of mobile endonucleases or recombinases. It appears that the eukaryotic versions have emerged from versions of the domain associated with mobile elements, followed by independent lineage-specific expansions, which accompanied their recruitment to transcription regulation functions.

Amino Acid Sequence↗
PubMed1998

Haemoproteus (Apicomplexa: Haemoproteidae) of tortoises and turtles.

It is the general opinion that the haemoproteid blood parasites of chelonians belong to the genus Haemoproteus. Different specific names have long been assigned to this parasite in birds, but some past authorities have accepted only a single species, H. metchnikovi, for all those haemoproteids recorded in a wide range of chelonian genera throughout the world. In the present study, a comparison of one such organism in the tortoise Geochelone denticulata with another in the river turtle Peltocephalus dumerilianus, from Amazonian Brazil, has revealed clear morphological differences. These distinguish the parasites from each other, H. metchnikovi and the other named species of chelonian Haemoproteus for which adequate descriptions are available. We have assigned to them the names Haemoproteus geochelonis n.sp. and Haemoproteus peltocephali n.sp.

Animals↗
PubMed2003

Phylogeny of gregarines (Apicomplexa) as inferred from small-subunit rDNA and beta-tubulin.

Gregarines are thought to be deep-branching apicomplexans. Accordingly, a robust inference of gregarine phylogeny is crucial to any interpretation of apicomplexan evolution, but molecular sequences from gregarines are restricted to a small number of small-subunit (SSU) rDNA sequences from derived taxa. This work examines the usefulness of SSU rDNA and beta-tubulin sequences for inferring gregarine phylogeny. SSU rRNA genes from Lecudina (Mingazzini) sp., Monocystis agilis Stein, Leidyana migrator Clopton and Gregarina polymorpha Dufour, as well as the beta-tubulin gene from Leidyana migrator, were sequenced. The results of phylogenetic analyses of alveolate taxa using both genes were consistent with an early origin of gregarines and the putative 'sister' relationship between gregarines and Cryptosporidium, but neither phylogeny was strongly supported. In addition, two SSU rDNA sequences from unidentified marine eukaryotes were found to branch among the gregarines: one was a sequence derived from the haemolymph parasite of the giant clam, Tridacna crocea, and the other was a sequence misattributed to the foraminiferan Ammonium beccarii. In all of our analyses, the SSU rDNA sequence from Colpodella sp. clustered weakly with the apicomplexans, which is consistent with ultrastructural data. Altogether, the exact position of gregarines with respect to Cryptosporidium and other apicomplexans remains to be confirmed, but the congruence of SSU rDNA and beta-tubulin trees with one another and with morphological data does suggest that further sampling of molecular data will eventually put gregarine diversity into a phylogenetic context.

Animals↗
PubMed1984

Besnoitia darlingi (Apicomplexa, Sarcocystidae, Toxoplasmatinae): transmission between opossums and cats.

Opossums (Didelphis marsupialis), act as intermediate hosts for Besnoitia darlingi and could be infected orally with sporozoites (oocysts) and bradyzoites (tissue cysts), or intraperitoneally (i.p.) with tachyzoites. Infections could presumably be transmitted through cannibalism. Cats (Felis catus), the definitive host, could be infected only with bradyzoites but not sporozoites. Oocysts shed by cats measure about 12 X 12 microns, resemble similarly sized oocysts of Toxoplasma gondii and Hammondia hammondi, and must be differentiated by the appearance of tissue cysts after experimental infection of intermediate hosts. Cats did not form tissue cysts of B. darlingi. Tachyzoites from the related B. jellisoni could be used in the Sabin-Feldman dye test to determine the development of antibody to B. darlingi in opossums after infection.

Animals↗
PubMed1985

Klossiella (Apicomplexa, Klossiellidae) in petaurid and macropodid marsupials in Australia.

Six new species of Klossiella are described in the kidneys of Australian marsupials: Klossiella rufogrisei in Bennett's Wallaby, Macropus rufogriseus; Klossiella rufi in the Red Kangaroo, Macropus rufus; Klossiella thylogale in the Red-Bellied or Tasmanian Pademelon, Thylogale billardierii; Klossiella beveridgei in the Spectacled Hare-Wallaby, Lagorchestes conspicillatus; Klossiella bettongiae in the Tasmanian Bettong, Bettongia gaimardi; and Klossiella schoinobatis in the petaurid Greater Glider, Petauroides volans. It is concluded that the genus Klossiella has radiated widely among Australian marsupials, and that since it is present in American marsupials, it may have an ancient association with the subclass.

Animals↗
PubMed1988

Ultrastructural features of the apical complex, pellicle, and membranes investing the gamonts of Haemogregarina magna (Apicomplexa: Adeleina).

Mature gamonts of Haemogregarina magna lie within a type of parasitophorous vacuole (Pv) apparently unique to the haemogregarines. The cytoplasm of infected erythrocytes was separated from the parasite by two Pv membranes. An additional membrane, coated on both sides with electron-dense material, closely invested the gamonts. The apical complex of the gamonts includes a conoid, two preconoidal rings, and an elaborate polar ring complex. The latter consisted of the polar ring and approximately 78 posteriorly directed, radially arranged, "tine-like" structures which fuse as they merge anteriorly into the polar ring. Freeze fracture replicas demonstrated that the pellicle of gamonts of H. magna was structurally similar to that of other apicomplexans. The closely apposed inner membranes of the pellicle formed plates which were arranged into strips along the long axis of the gamont. Calculations indicated that 13 such strips are found around the circumference of the gamonts with about six subpellicular microtubules associated with the inner surface of each strip. Gamonts of H. magna share many structural similarities with the kinetes, ookinetes, and sporokinetes of other apicomplexans. We propose that the conoid and polar ring complex are fundamental features of all apicomplexan "kinetes."

Animals↗