Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 323
Filtrar
1.
J Eukaryot Microbiol ; 67(1): 4-17, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31231936

RESUMO

Eugregarines are understudied apicomplexan parasites of invertebrates inhabiting marine, freshwater, and terrestrial environments. Most currently known terrestrial eugregarines have been described parasitizing the gut from less than 1% of total insect diversity, with a high likelihood that the remaining insect species are infected. Eugregarine diversity in orthopterans (grasshoppers, locusts, katydids, and crickets) is still little known. We carried out a survey of the eugregarines parasitizing the Mexican lubber grasshopper, Taeniopoda centurio, an endemic species to the northwest of Mexico. We described two new eugregarine species from the gut of the host: Amoebogregarina taeniopoda n. sp. and Quadruspinospora mexicana n. sp. Both species are morphologically dissimilar in their life-cycle stages. Our SSU rDNA phylogenetic analysis showed that both species are phylogenetically distant to each other, even though they parasitize the same host. Amoebogregarina taeniopoda n. sp. clustered within the clade Gregarinoidea, being closely related to Amoebogregarina nigra from the grasshopper Melanoplus differentialis. Quadruspinospora mexicana n. sp. clustered within the clade Actinocephaloidea and grouped with Prismatospora evansi, a parasite from dragonfly naiads. Amoebogregarina taeniopoda n. sp. and Q. mexicana n. sp. represent the first record of eugregarines found to infect a species of the family Romaleidae.


Assuntos
Apicomplexa/classificação , Apicomplexa/citologia , Gafanhotos/parasitologia , Interações Hospedeiro-Parasita , Filogenia , Animais , Apicomplexa/ultraestrutura , DNA de Protozoário/análise , DNA Ribossômico/análise , México , Microscopia , Microscopia Eletrônica de Varredura , Análise de Sequência de DNA
2.
Parasitol Res ; 118(9): 2651-2667, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31270680

RESUMO

Representatives of Apicomplexa perform various kinds of movements that are linked to the different stages of their life cycle. Ancestral apicomplexan lineages, including gregarines, represent organisms suitable for research into the evolution and diversification of motility within the group. The vermiform trophozoites and gamonts of the archigregarine Selenidium pygospionis perform a very active type of bending motility. Experimental assays and subsequent light, electron, and confocal microscopic analyses demonstrated the fundamental role of the cytoskeletal proteins actin and tubulin in S. pygospionis motility and allowed us to compare the mechanism of its movement to the gliding machinery (the so-called glideosome concept) described in apicomplexan zoites. Actin-modifying drugs caused a reduction in the movement speed (cytochalasin D) or stopped the motility of archigregarines completely (jasplakinolide). Microtubule-disrupting drugs (oryzalin and colchicine) had an even more noticeable effect on archigregarine motility. The fading and disappearance of microtubules were documented in ultrathin sections, along with the formation of α-tubulin clusters visible after the immunofluorescent labelling of drug-treated archigregarines. The obtained data indicate that subpellicular microtubules most likely constitute the main motor structure involved in S. pygospionis bending motility, while actin has rather a supportive function.


Assuntos
Apicomplexa/crescimento & desenvolvimento , Apicomplexa/fisiologia , Citoesqueleto/metabolismo , Proteínas de Protozoários/metabolismo , Actinas/metabolismo , Animais , Apicomplexa/ultraestrutura , Citoesqueleto/ultraestrutura , Tomografia com Microscopia Eletrônica , Microtúbulos/metabolismo , Parasitos , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/metabolismo , Trofozoítos/ultraestrutura , Tubulina (Proteína)/metabolismo
3.
J Parasitol ; 105(3): 454-458, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31237483

RESUMO

Gregarine transmission depends upon the environmental encounter rate between viable infective oocysts and suitable hosts. Many factors determine the abundance and distribution of gregarine oocysts in the environment, but the primary factors are oocyst distribution, environmental persistence, and production rate. Prior studies have demonstrated factors affecting oocyst distribution and environmental persistence, but oocyst production rate is poorly understood. This study addresses the effects of gametocyst size on oocyst production. For each of 3 gregarine species, gametocyst size was determined, and the subsequent oocyst production of each gametocyst was quantified. Gregarine species with larger gametocysts produced more oocysts per gametocyst than species with smaller gametocysts. Likewise, within species, larger gametocysts produced more oocysts. The effect was stronger in larger gregarine species, probably as a reflection of the lower overall range of gametocyst size in the smaller gregarine species.


Assuntos
Apicomplexa/fisiologia , Baratas/parasitologia , Animais , Apicomplexa/ultraestrutura , Meio Ambiente , Oocistos/fisiologia , Oocistos/ultraestrutura , Reprodução
4.
Rev Bras Parasitol Vet ; 28(1): 97-104, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30916259

RESUMO

This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.


Assuntos
Apicomplexa/ultraestrutura , Crassostrea/parasitologia , Oocistos/ultraestrutura , Fagócitos/ultraestrutura , Animais , Apicomplexa/isolamento & purificação , Brasil , Microscopia Eletrônica de Transmissão
5.
Rev. bras. parasitol. vet ; 28(1): 97-104, Jan.-Mar. 2019. graf
Artigo em Inglês | LILACS | ID: biblio-990811

RESUMO

Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.


Resumo Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis (Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.


Assuntos
Animais , Fagócitos/ultraestrutura , Apicomplexa/ultraestrutura , Oocistos/ultraestrutura , Crassostrea/parasitologia , Brasil , Apicomplexa/isolamento & purificação , Microscopia Eletrônica de Transmissão
6.
Protist ; 169(6): 826-852, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30453272

RESUMO

Archigregarines are a key group for understanding the early evolution of Apicomplexa. Here we report morphological, ultrastructural, and molecular phylogenetic evidence from two archigregarine species: Selenidium pygospionis sp. n. and S. pherusae sp. n. They exhibited typical features of archigregarines. Additionally, an axial row of vacuoles of a presumably nutrient distribution system was revealed in S. pygospionis. Intracellular stages of S. pygospionis found in the host intestinal epithelium may point to the initial intracellular localization in the course of parasite development. Available archigregarine SSU (18S) rDNA sequences formed four major lineages fitting the taxonomical affiliations of their hosts, but not the morphological or biological features used for the taxonomical revision by Levine (1971). Consequently, the genus Selenidioides Levine, 1971 should be abolished. The branching order of these lineages was unresolved; topology tests rejected neither para- nor monophyly of archigregarines. We provided phylogenies based on LSU (28S) rDNA and near-complete ribosomal operon (concatenated SSU, 5.8S, LSU rDNAs) sequences including S. pygospionis sequences. Although being preliminary, they nevertheless revealed the monophyly of gregarines previously challenged by many molecular phylogenetic studies. Despite their molecular-phylogenetic heterogeneity, archigregarines exhibit an extremely conservative plesiomorphic structure; their ultrastructural key features appear to be symplesiomorphies rather than synapomorphies.


Assuntos
Apicomplexa/classificação , Apicomplexa/isolamento & purificação , Organismos Aquáticos/classificação , Organismos Aquáticos/isolamento & purificação , Filogenia , Animais , Apicomplexa/genética , Apicomplexa/ultraestrutura , Organismos Aquáticos/genética , Organismos Aquáticos/ultraestrutura , Análise por Conglomerados , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Locomoção , Microscopia , Microscopia Eletrônica , Poliquetos/parasitologia , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , RNA Ribossômico 5,8S/genética , Análise de Sequência de DNA
7.
Protist ; 169(5): 697-726, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30125804

RESUMO

Blastogregarines are poorly studied parasites of polychaetes superficially resembling gregarines, but lacking syzygy and gametocyst stages in the life cycle. Furthermore, their permanent multinuclearity and gametogenesis by means of budding considerably distinguish them from other parasitic Apicomplexa such as coccidians and hematozoans. The affiliation of blastogregarines has been uncertain: different authors considered them highly modified gregarines, an intermediate apicomplexan lineage between gregarines and coccidians, or an isolated group of eukaryotes altogether. Here, we report the ultrastructure of two blastogregarine species, Siedleckia nematoides and Chattonaria mesnili, and provide the first molecular data on their phylogeny based on SSU, 5.8S, and LSU rDNA sequences. Morphological analysis reveals that blastogregarines possess both gregarine and coccidian features. Several traits shared with archigregarines likely represent the ancestral states of the corresponding cell structures for parasitic apicomplexans: a distinctive tegument structure and myzocytotic feeding with a well-developed apical complex. Unlike gregarines but similar to coccidians however, the nuclei of male blastogregarine gametes are associated with two kinetosomes. Molecular phylogenetic analyses reveal that blastogregarines are an independent, early diverging lineage of apicomplexans. Overall, the morphological and molecular evidence congruently suggests that blastogregarines represent a separate class of Apicomplexa.


Assuntos
Apicomplexa/crescimento & desenvolvimento , Apicomplexa/genética , Filogenia , Apicomplexa/classificação , Apicomplexa/ultraestrutura , Corpos Basais/metabolismo , DNA de Protozoário/genética , Células Germinativas/crescimento & desenvolvimento , Células Germinativas/ultraestrutura , Ativação Linfocitária , Microscopia Eletrônica
8.
J Eukaryot Microbiol ; 65(5): 637-647, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29399925

RESUMO

Marine gregarines are unicellular parasites of invertebrates commonly found infecting the intestine and coelomic spaces of their hosts. Situated at the base of the apicomplexan tree, marine gregarines offer an opportunity to explore the earliest stages of apicomplexan evolution. Classification of marine gregarines is often based on the morphological traits of the conspicuous feeding stages (trophozoites) in combination with host affiliation and molecular phylogenetic data. Morphological characters of other life stages such as the spore are also used to inform taxonomy when such stages can be found. The reconstruction of gregarine evolutionary history is challenging, due to high levels of intraspecific variation of morphological characters combined with relatively few traits that are taxonomically unambiguous. The current study combined morphological data with a phylogenetic analysis of small subunit rDNA sequences to describe and establish a new genus and species (Cuspisella ishikariensis n. gen., n. sp.) of marine gregarine isolated from the intestine of a polynoid host (Lepidonotus helotypus) collected from Hokkaido, Japan. This new species possesses a set of unusual morphological traits including a spiked attachment apparatus and sits on a long branch on the molecular phylogeny. Furthermore, this study establishes a molecular phylogenetic position for Loxomorpha cf. harmothoe, a previously described marine gregarine, and reveals a new group of gregarines that infect polynoid hosts.


Assuntos
Apicomplexa/isolamento & purificação , Poliquetos/parasitologia , Animais , Apicomplexa/classificação , Apicomplexa/genética , Apicomplexa/ultraestrutura , DNA de Protozoário/genética , Intestinos/parasitologia , Japão , Filogenia , Trofozoítos/genética , Trofozoítos/crescimento & desenvolvimento , Trofozoítos/isolamento & purificação , Trofozoítos/ultraestrutura
9.
Eur J Protistol ; 60: 60-67, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28662493

RESUMO

Gregarine apicomplexans are unicellular organisms that infect invertebrate hosts in marine, freshwater and terrestrial habitats. The largest group of invertebrates infested on land is the insects. The insect order Psocoptera (booklice) has recently gained wider interest due to specimens occurring in stored food products and therefore being considered pest organisms. Biological control agents are often used to eliminate pest organisms. In this study we examined the psocid Dorypteryx domestica, an invasive psocid species that is spreading all over the world. We were able to isolate and describe a new gregarine species (Enterocystis dorypterygis sp. n.) infecting D. domestica. The trophozoites are panduri- or pyriform and their association/syzygy is caudo-frontal. The surface is inscribed by longitudinal epicytic folds covering the complete cell. Phylogenetic analyses of the SSU rDNA gene revealed an only weakly supported relationship with two Gregarina species G. ormieri and G. basiconstrictonea, both from tenebrionid beetles. Gregarines have been proposed to have some potential as biological control agents for several insects. Identifying the gregarine species infecting pest organisms like psocids is a first step and prerequisite for the probable utilization of these parasites as biological control agents in the future.


Assuntos
Apicomplexa/classificação , Apicomplexa/fisiologia , Insetos/parasitologia , Animais , Apicomplexa/genética , Apicomplexa/ultraestrutura , DNA Ribossômico/genética , Filogenia , Especificidade da Espécie
10.
PLoS One ; 12(6): e0179709, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28640849

RESUMO

Recent studies on motility of Apicomplexa concur with the so-called glideosome concept applied for apicomplexan zoites, describing a unique mechanism of substrate-dependent gliding motility facilitated by a conserved form of actomyosin motor and subpellicular microtubules. In contrast, the gregarines and blastogregarines exhibit different modes and mechanisms of motility, correlating with diverse modifications of their cortex. This study focuses on the motility and cytoskeleton of the blastogregarine Siedleckia nematoides Caullery et Mesnil, 1898 parasitising the polychaete Scoloplos cf. armiger (Müller, 1776). The blastogregarine moves independently on a solid substrate without any signs of gliding motility; the motility in a liquid environment (in both the attached and detached forms) rather resembles a sequence of pendular, twisting, undulation, and sometimes spasmodic movements. Despite the presence of key glideosome components such as pellicle consisting of the plasma membrane and the inner membrane complex, actin, myosin, subpellicular microtubules, micronemes and glycocalyx layer, the motility mechanism of S. nematoides differs from the glideosome machinery. Nevertheless, experimental assays using cytoskeletal probes proved that the polymerised forms of actin and tubulin play an essential role in the S. nematoides movement. Similar to Selenidium archigregarines, the subpellicular microtubules organised in several layers seem to be the leading motor structures in blastogregarine motility. The majority of the detected actin was stabilised in a polymerised form and appeared to be located beneath the inner membrane complex. The experimental data suggest the subpellicular microtubules to be associated with filamentous structures (= cross-linking protein complexes), presumably of actin nature.


Assuntos
Apicomplexa/citologia , Apicomplexa/fisiologia , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Movimento/efeitos dos fármacos , Apicomplexa/efeitos dos fármacos , Apicomplexa/ultraestrutura , Microscopia , Trofozoítos/efeitos dos fármacos , Trofozoítos/fisiologia
11.
Eur J Protistol ; 59: 1-13, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28363137

RESUMO

Gregarines represent a highly diversified group of ancestral apicomplexans, with various modes of locomotion and host-parasite interactions. The eugregarine parasite of the barnacle Balanus balanus, Cephaloidophora cf. communis, exhibits interesting organisation of its attachment apparatus along with unique motility modes. The pellicle covered gregarine is arranged into longitudinal epicytic folds. The epimerite is separated from the protomerite by a septum consisting of tubulin-rich filamentous structures and both are packed with microneme-like structures suggestive of their function in the production of adhesives important for attachment and secreted through the abundant epimerite pores. Detached trophozoites and gamonts are capable of gliding motility, enriched by jumping and rotational movements with rapid changes in gliding direction and cell flexions. Actin in its polymerised form (F-actin) is distributed throughout the entire gregarine, while myosin, detected in the cortical region of the cell, follows the pattern of the epicytic folds. Various motility modes exhibited by individuals of C. cf. communis, together with significant changes in their cell shape during locomotion, are not concordant with the gliding mechanisms generally described in apicomplexan zoites and indicate that additional structures must be involved (e.g. two 12-nm filaments; the specific dentate appearance of internal lamina inside the epicytic folds).


Assuntos
Apicomplexa/fisiologia , Apicomplexa/ultraestrutura , Atividade Motora , Thoracica/parasitologia , Animais , Interações Hospedeiro-Parasita
12.
Eur J Protistol ; 59: 26-33, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28363139

RESUMO

Chrysomela populi (Coleoptera: Chrysomelidae) is the most abundant and most important pest species that causes damage to poplar trees. Members of the family Chrysomelidae are frequently infected by protist pathogens but no neogregarine has been reported to date at the species level. In the present study we identify a new neogregarine pathogen from the chrysomelid C. populi. The infection was observed in the Malpighian tubules of adult beetles. A reddening of the Malpighian tubules was the most distinctive symptom of the infection. Single fusiform oocysts (9.8×4.7µm) were formed within a gamontocyst. The polar plugs were very thin, varying from 380 to 525nm in thickness. The oocyst wall was smooth and also quite thin (90-120nm). Morphological and ultrastructural characteristics of the pathogen indicate that the described neogregarine in C. populi is clearly different from known Ophryocystis species which infect coleopterans. Therefore, the neogregarine pathogen was determined to be a newly discovered species and named Ophryocystis anatoliensis sp. nov.


Assuntos
Apicomplexa/classificação , Besouros/parasitologia , Animais , Apicomplexa/fisiologia , Apicomplexa/ultraestrutura , Túbulos de Malpighi/parasitologia , Especificidade da Espécie
13.
J Parasitol ; 103(3): 228-236, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28323544

RESUMO

Understanding host-parasite interactions is essential for ecological research, wildlife conservation, and health management. While most studies focus on numerical traits of parasite groups, such as changes in parasite load, less focus is placed on the traits of individual parasites such as parasite size and shape (parasite morphology). Parasite morphology has significant effects on parasite fitness such as initial colonization of hosts, avoidance of host immune defenses, and the availability of resources for parasite replication. As such, understanding factors that affect parasite morphology is important in predicting the consequences of host-parasite interactions. Here, we studied how host diet affected the spore morphology of a protozoan parasite ( Ophryocystis elektroscirrha ), a specialist parasite of the monarch butterfly ( Danaus plexippus ). We found that different host plant species (milkweeds; Asclepias spp.) significantly affected parasite spore size. Previous studies have found that cardenolides, secondary chemicals in host plants of monarchs, can reduce parasite loads and increase the lifespan of infected butterflies. Adding to this benefit of high cardenolide milkweeds, we found that infected monarchs reared on milkweeds of higher cardenolide concentrations yielded smaller parasites, a potentially hidden characteristic of cardenolides that may have important implications for monarch-parasite interactions.


Assuntos
Apicomplexa/ultraestrutura , Borboletas/parasitologia , Animais , Apicomplexa/crescimento & desenvolvimento , Asclepias/química , Borboletas/fisiologia , Cardenolídeos/metabolismo , Dieta , Feminino , Interações Hospedeiro-Parasita , Masculino , Esporos de Protozoários/ultraestrutura
15.
Sci Rep ; 7(1): 175, 2017 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-28282967

RESUMO

Gregarines (Apicomplexa) are a diverse group of protozoan parasites, which infects gut and other body cavities of invertebrate hosts. In reproductive system of insects, gregarine has been reported only in the accessory glands and spermathecae of females; therefore, this is the first report of a gregarine species in seminal vesicles of insects. Different developmental stages, including sporozoytes, oocysts and trophozoites were described from morphological descriptions using light and electron transmission microscopy. The parasites were described in seminal vesicles of the beetle Tribolium castaneum a model organism and an important insect pest. DNA sequence analysis suggests that the protozoan parasite was an Ascogregarina sp.


Assuntos
Apicomplexa/classificação , Apicomplexa/crescimento & desenvolvimento , Besouros/parasitologia , Análise de Sequência de DNA/métodos , Animais , Apicomplexa/genética , Apicomplexa/ultraestrutura , DNA de Protozoário/genética , Feminino , Masculino , Microscopia Eletrônica de Transmissão , Filogenia , Glândulas Seminais/parasitologia
16.
J Invertebr Pathol ; 144: 58-64, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28167046

RESUMO

In this study, a new genus and species of neogregarine which is a pathogen of Anisoplia segetum Herbst (Coleoptera: Scarabaeidae), is described. The adult beetles of A. segetum were collected from Nevsehir, Turkey and neogregarine infection rates were determined as 18.52%. The Giemsa-stained mature oocysts are lemon-shaped and measured 9.34±0.82µm in length and 5.77±0.77µm in width. The oocyst wall surface of the mature oocysts is similar to an osage orange (tuberculate). Morphological, ultrastructural and molecular features indicate that the previously undescribed neogregarine is dissimilar to all known neogregarine taxa and represents the first record from Anisoplia segetum and is named here as Aranciocystis muskarensis n. gen., n. sp.


Assuntos
Apicomplexa/fisiologia , Besouros/microbiologia , Animais , Apicomplexa/ultraestrutura , Genes de Protozoários , Microscopia Eletrônica , Filogenia , Reação em Cadeia da Polimerase , Turquia
17.
Parasitology ; 144(4): 419-425, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28073394

RESUMO

A high degree of specialization between host and parasite is a well-known outcome of a long history of coevolution, and it is strikingly illustrated in a coordination of their life cycles. In some cases, the arms race ensued at the establishment of a symbiotic relationship results in the adoption of manipulative strategies by the parasite. We have already learned that Steinina ctenocephali, a gregarine living in the alimentary canal of cat flea, Ctenocephalides felis follows its phenology and metamorphosis. Despite these findings the outcome of their symbiotic partnership (mutualist, parasitic or commensal) remains unclear. To address this important question, we measured life history parameters of the flea in the presence of varying infection intensities of gregarine oocysts in laboratory conditions. We found that neither the emergence nor survival rate of fleas was affected by harbouring the gregarines. More surprisingly, our results show that flea larvae infected with gregarines developed faster and emerged earlier than the control group. This gregarine therefore joins the selected group of protists that can modify physiological host traits and provides not only new model taxa to be explored in an evolutionary scenario, but also potential development of control strategies of cat flea.


Assuntos
Apicomplexa/fisiologia , Ctenocephalides/parasitologia , Animais , Apicomplexa/ultraestrutura , Ctenocephalides/crescimento & desenvolvimento , Ctenocephalides/ultraestrutura , Feminino , Interações Hospedeiro-Parasita , Larva/crescimento & desenvolvimento , Larva/parasitologia , Larva/ultraestrutura , Masculino , Oocistos
18.
J Eukaryot Microbiol ; 64(1): 56-66, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27288198

RESUMO

A novel species of aseptate eugregarine, Ganymedes yurii sp. n., is described using microscopic and molecular approaches. It inhabits the intestine of Gondogeneia sp., a benthic amphipod found along the shore of James Ross Island, Weddell Sea, Antarctica. The prevalence of the infection was very low and only a few caudo-frontal syzygies were found. Morphologically, the new species is close to a previously described amphipod gregarine, Ganymedes themistos, albeit with several dissimilarities in the structure of the contact zone between syzygy partners, as well as other characteristics. Phylogenetic analysis of the 18S rDNA from G. yurii supported a close relationship between these species. These two species were grouped with other gregarines isolated from crustaceans hosts (Cephaloidophoroidea); however, statistical support throughout the clade of Cephaloidophoroidea gregarines was minimal using the available dataset.


Assuntos
Anfípodes/parasitologia , Apicomplexa/ultraestrutura , Animais , Regiões Antárticas , Apicomplexa/classificação , Apicomplexa/genética , Sequência de Bases , DNA de Protozoário/genética , DNA Ribossômico/genética , Microscopia , Microscopia Eletrônica de Transmissão , Filogenia , RNA Ribossômico 18S/genética , Análise de Sequência de DNA
19.
Protist ; 167(4): 339-368, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27423403

RESUMO

Archigregarines, an early branching lineage within Apicomplexa, are a poorly-known group of invertebrate parasites. By their phylogenetic position, archigregarines are an important lineage to understand the functional transition that occurred between free-living flagellated predators to obligatory parasites in Apicomplexa. In this study, we provide new ultrastructural data and phylogenies based on SSU rDNA sequences using the type species of archigregarines, the Selenidiidae Selenidium pendulaGiard, 1884. We describe for the first time the syzygy and early gamogony at the ultrastructural level, revealing a characteristic nuclear multiplication with centrocones, cryptomitosis, filamentous network of chromatin, a cyst wall secretion and a 9+0 flagellar axoneme of the male gamete. S. pendula belongs to a monophyletic lineage that includes several other related species, all infecting Sedentaria Polychaeta (Spionidae, Sabellaridae, Sabellidae and Cirratulidae). All of these Selenidium species exhibit similar biological characters: a cell cortex with the plasma membrane - inner membrane complex - subpellicular microtubule sets, an apical complex with the conoid, numerous rhoptries and micronemes, a myzocytosis with large food vacuoles, a nuclear multiplication during syzygy and young gamonts. Two other distantly related Selenidium-like lineages infect Terebellidae and Sipunculida, underlying the ability of archigregarines to parasite a wide range of marine hosts.


Assuntos
Apicomplexa/classificação , Apicomplexa/ultraestrutura , Filogenia , Apicomplexa/genética , Apicomplexa/crescimento & desenvolvimento , DNA de Protozoário/genética , DNA Ribossômico/genética , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
20.
Bull Entomol Res ; 106(2): 258-67, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26781173

RESUMO

Tribolium castaneum Herbst 1797 (Coleoptera: Tenebrionidae), an important pest of stored grains and byproducts, is naturally infected by Gregarina cuneata Stein 1848 (Apicomplexa: Gregarinidae). Changes in the life cycle of insects caused by the parasite development in the midgut were studied. Trophozoites, gamonts (solitary and associated), and gametocysts were present in the midgut of the insects. In young trophozoites, the apical region differentiated into an epimerite that firmly attached the parasite to the host epithelial cells. With maturation, trophozoites developed in gamonts that were associated with the initiation of sexual reproduction in the cell cycle, culminating in the formation of the spherical gametocyst. Morpho-functional analyses indicated that gregarines absorb nutrients from infected cells and can occlude the midgut as they develop. Consequently, nutritional depletion may interfere with the host's physiology, causing decreased growth, delayed development, and high mortality rates of the parasitized insects. These results suggest G. cuneata could be an important biological agent for controlling T. castaneum in integrated pest management programs.


Assuntos
Apicomplexa/crescimento & desenvolvimento , Estágios do Ciclo de Vida , Controle Biológico de Vetores , Tribolium/parasitologia , Animais , Apicomplexa/fisiologia , Apicomplexa/ultraestrutura , Feminino , Masculino , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tribolium/crescimento & desenvolvimento , Tribolium/ultraestrutura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...