scholarly journals Cellular distribution of a feminizing microsporidian parasite: a strategy for transovarial transmission

Parasitology ◽  
1997 ◽  
Vol 115 (2) ◽  
pp. 157-163 ◽  
Author(s):  
R. S. TERRY ◽  
A. M. DUNN ◽  
J. E. SMITH
Keyword(s):  
Polar Filament ◽  
Ovarian Tissue ◽  
Spore Wall ◽  
Follicle Cells ◽  
Transovarial Transmission ◽  
Cellular Distribution ◽  
Microsporidian Parasite ◽  
Daughter Cells ◽  
Adult Females ◽  
Perinuclear Cytoplasm

The cellular distribution of a vertically transmitted, feminizing microsporidian was followed in its host Gammarus duebeni. In adult females the parasite was restricted to gonadal tissue, in particular primary and secondary follicle cells. Spores were diplokaryotic with a thin spore wall and a short polar filament, characteristics typical of ‘early’ spores involved in autoinfection. The diplokaryotic life-cycle, absence of spore groupings and of a pansporoblast membrane typify the genus Nosema. However, the unusual globular polaroplast of the spore and restriction of this stage to host ovarian tissue have not previously been described in Nosema. Sporogony occurred only in follicle cells adjacent to developing oocytes and was in synchrony with the process of vitellogenesis. Oocytes were infected after formation of intracellular connections with follicle cells but harboured only vegetative stages of the parasite. Parasites were associated with the perinuclear cytoplasm and, in developing embryos, segregated to daughter cells along the axis of the spindle. In juvenile animals there was no evidence of pathology linked with feminization and the parasite was found at low density in cells under the cuticle. The parasite is highly adapted to transovarial transmission with an efficient mechanism of oocyte infection and no evidence of pathology.

Pathogénie, cycle de développement et ultrastructure d'Amblyospora culicis n. sp. (Protozoa, Microspora), parasite du moustique Culex quinquefasciatus Say, 1823 (Diptera, Culicidae)

1985 ◽  
Vol 63 (8) ◽  
pp. 1797-1809 ◽  
Author(s):  
Bhen Sikina Toguebaye ◽  
Bernard Marchand
Keyword(s):  
Plasma Membrane ◽  
Culex Quinquefasciatus ◽  
Polar Filament ◽  
Microsporidian Parasite ◽  
Male And Female ◽  
Adult Females

Amblyospora culicis n. sp. is a new microsporidian parasite of the mosquito Culex quinquefasciatus Say, 1823 (Diptera, Culicidae). It infects the adipose and nervous tissues of male and female larvae and adults, as well as the ovaries of adult females. The observed meronts have, in turn, one, then two diplokaryons constituted of diploid nuclei. The sporogony is pansporoblastic and octosporous. At first, diplokariotic meronts transform into diplokaryotic presporonts bounded by a wall. Then, the plasma membrane of the presporont detaches itself from the wall, thus creating a pansporoblastic vacuole. A new wall appears around the presporont which thus becomes a sporont. Its two nuclei separate from each other, then the cytoplasm divides to form two uninucleate sporonts. Each then undergoes two meiotic divisions which end in the formation of eight uninucleate and haploid sporonts. These sporonts evolve into sporoblasts, then into spores. The spores are ovoid, uninucleate, and haploid (8.55 ± 0.13 × 6.46 ± 0.08 μm). They are bounded by a wall having a thick multilayered exospore and contain a polar filament abruptly constricted in its coiled part.

scholarly journals Tick Ecdysteroid Hormone, Global Microbiota/Rickettsia Signaling in the Ovary versus Carcass during Vitellogenesis in Part-Fed (Virgin) American Dog Ticks, Dermacentor variabilis

2021 ◽  
Vol 9 (6) ◽  
pp. 1242
Author(s):  
Loganathan Ponnusamy ◽  
Haley Sutton ◽  
Robert D. Mitchell ◽  
Daniel E. Sonenshine ◽  
Charles S. Apperson ◽  
...  
Keyword(s):  
Hormonal Regulation ◽  
Natural Populations ◽  
Blood Feeding ◽  
Dermacentor Variabilis ◽  
Transovarial Transmission ◽  
Rickettsia Species ◽  
Adult Females ◽  
Dog Tick ◽  
Total Bacteria

The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake by the eggs but has no effect on blood feeding. Francisella sp. and R. montanensis were the predominant bacteria based on the proportionality in the carcass and ovary. The total bacteria load increased in the carcass and ovaries, and bacteria in the genus Pseudomonas increased in the carcass after the 20E injection. The mechanism of how the Rickettsia species respond to changes in tick hormonal regulation needs further investigation. Multiple possible mechanisms for the proliferation of R. montanensis in the ovaries are proposed.

Infection of American smelt in Lake Ontario and Lake Erie with the microsporidian parasite Glugea hertwigi (Weissenberg)

1972 ◽  
Vol 50 (9) ◽  
pp. 1183-1188 ◽  
Author(s):  
M. Chen ◽  
G. Power
Keyword(s):  
Digestive Tract ◽  
Lake Erie ◽  
Ovarian Tissue ◽  
Lake Ontario ◽  
Parasite Load ◽  
Sexual Differences ◽  
Striking Difference ◽  
Female Fish ◽  
Microsporidian Parasite ◽  
Male Fish

In samples taken monthly throughout the year the percentage of American smelt in Lake Ontario and Lake Erie containing cysts of Glugea hertwigi was 5.2% and 62.7% respectively. Sexual differences in incidence were observed, the significance of which was uncertain as results from the two lakes were contradictory.In male fish infection was almost entirely restricted to the digestive tract with few cysts in the liver, skin, and testes. In female fish the digestive tract and ovaries were similarly infected.Seasonal fluctuations in Glugea infection were obvious and seemed correlated with the gonadal cycle. In both sexes the highest parasite load corresponded with the onset of maturation.A striking difference in fecundity between the two smelt populations was attributed to the Glugea infection. In females parasite cysts replaced ovarian tissue, causing a reduction in the number of maturing eggs.

A new microsporidian parasite, Heterosporis saurida n. sp. (Microsporidia) infecting the lizardfish, Saurida undosquamis from the Arabian Gulf, Saudi Arabia: ultrastructure and phylogeny

Parasitology ◽  
2012 ◽  
Vol 139 (4) ◽  
pp. 454-462 ◽  
Author(s):  
S. AL-QURAISHY ◽  
A. S. ABDEL-BAKI ◽  
H. AL-QAHTANI ◽  
M. DKHIL ◽  
G. CASAL ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Polar Filament ◽  
Phylogenetic Analyses ◽  
Abdominal Cavity ◽  
Arabian Gulf ◽  
Its Region ◽  
Rrna Genes ◽  
Microsporidian Parasite ◽  
Ultrastructural Characteristics ◽  
A New Species

SUMMARYA new microsporidian that infects the lizardfish Saurida undosquamis (Richardson, 1848) that are caught in the Arabian Gulf in Saudi Arabia is described here. This parasite invades the skeletal muscle of the abdominal cavity forming white, cyst-like structures containing numerous spores. The prevalence of the infection was 32·1% (135/420). The spores were oval to pyriform in shape and measured approximately 3·3 μm×2·0 μm. The developing spores were found within parasitophorous vacuoles. In mature spores, the polar filament was arranged into 5 coils in a row. Molecular analysis of the rRNA genes, including the ITS region, and phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference were performed. The ultrastructural characteristics and phylogenetic analyses support the recognition of a new species, herein named Heterosporis saurida n. sp.

Cytologie et taxonomie d'une microsporidie du genre Unikaryon (Microspora, Unikaryonidae) parasite du Mylabris vestita (Coleoptera, Meloidae)

1988 ◽  
Vol 66 (2) ◽  
pp. 364-367 ◽  
Author(s):  
Bhen S. Toguebaye ◽  
Bernard Marchand
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Polar Filament ◽  
Malpighian Tubules ◽  
Microsporidian Parasite ◽  
Single Plasma

Unikaryon euzeti sp. nov. is a microsporidian parasite infesting the gut, adipose tissue, Malpighian tubules, and muscles of Mylabris vestita (Coleoptera, Meloidae). The meronts of U. euzeti are, in turn, uninucleate or binucleate and are surrounded by a single plasma membrane. The sporonts are also alternately uninucleate or binucleate but they are surrounded by a wall about 15 nm thick. The binucleate sporonts give rise to two uninucleate sporoblasts which turn into spores. Mature spores are uninucleate, ovoid, and measure 2.22 ± 0.11 × 1.38 ± 0.07 μm. Their polar filament describes seven to nine coils and their polaroplast is divided into an anterior lamellar part and a posterior granular one.

scholarly journals Cytological and molecular description of Hamiltosporidium tvaerminnensis gen. et sp. nov., a microsporidian parasite of Daphnia magna, and establishment of Hamiltosporidium magnivora comb. nov.

Parasitology ◽  
2010 ◽  
Vol 138 (4) ◽  
pp. 447-462 ◽  
Author(s):  
KAREN LUISA HAAG ◽  
J. I. RONNY LARSSON ◽  
DOMINIK REFARDT ◽  
DIETER EBERT
Keyword(s):  
Daphnia Magna ◽  
Sequence Data ◽  
Polar Filament ◽  
Molecular Data ◽  
Phylogenetic Position ◽  
Microsporidian Parasite ◽  
Isolated Nuclei ◽  
Host Interactions ◽  
Ultrastructural Characteristics ◽  
Molecular Description

SUMMARYWe describe the new microsporidium Hamiltosporidium tvaerminnensis gen. et sp. nov. with an emphasis on its ultrastructural characteristics and phylogenetic position as inferred from the sequence data of SSU rDNA, alpha- and beta-tubulin. This parasite was previously identified as Octosporea bayeri Jírovec, 1936 and has become a model system to study the ecology, epidemiology, evolution and genomics of microsporidia - host interactions. Here, we present evidence that shows its differences from O. bayeri. Hamiltosporidium tvaerminnensis exclusively infects the adipose tissue, the ovaries and the hypodermis of Daphnia magna and is found only in host populations located in coastal rock pool populations in Finland and Sweden. Merogonial stages of H. tvaerminnensis have isolated nuclei; merozoites are formed by binary fission or by the cleaving of a plasmodium with a small number of nuclei. A sporogonial plasmodium with isolated nuclei yields 8 sporoblasts. Elongated spores are generated by the most finger-like plasmodia. The mature spores are polymorphic in shape and size. Most spores are pyriform (4·9–5·6×2·2–2·3 μm) and have their polar filament arranged in 12–13 coils. A second, elongated spore type (6·8–12·0×1·6–2·1 μm) is rod-shaped with blunt ends and measures 6·8–12·0×1·6–2·1 μm. The envelope of the sporophorous vesicle is thin and fragile, formed at the beginning of the sporogony. Cytological and molecular comparisons with Flabelliforma magnivora, a parasite infecting the same tissues in the same host species, reveal that these two species are very closely related, yet distinct. Moreover, both cytological and molecular data indicate that these species are quite distant from F. montana, the type species of the genus Flabelliforma. We therefore propose that F. magnivora also be placed in Hamiltosporidium gen. nov.

scholarly journals Efficient Transovarial Transmission of Babesia Spp. in Rhipicephalus microplus Ticks Fed on Water Buffalo (Bubalus bubalis)

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 280
Author(s):  
Dasiel Obregón ◽  
Belkis Corona-González ◽  
Adrian Alberto Díaz-Sánchez ◽  
Yasmani Armas ◽  
Eugenio Roque ◽  
...  
Keyword(s):  
Adult Female ◽  
Tick Infestation ◽  
Water Buffalo ◽  
Larval Survival ◽  
Rhipicephalus Microplus ◽  
Babesia Bovis ◽  
Transovarial Transmission ◽  
Buffalo Calves ◽  
Adult Females ◽  
Babesia Spp

Water buffaloes can be infected by tick-borne pathogens (TBPs) in endemic areas where cattle and buffalo coexist. Among TBPs affecting buffaloes is the Apicomplexan hemoparasites Babesia bovis and B. bigemina, transmitted by Rhipicephalus microplus ticks. However, little empirical evidence exists on whether buffalo can support TBPs’ infection and transmission. A cohort study was designed to measure the infestation levels of R. microplus in buffaloes as well as the ability of buffalo-fed ticks to transmit B. bovis and B. bigemina to their offspring. Tick infestation of different life stages was quantified in cattle and buffalo kept in field conditions in western Cuba. Engorged adult female ticks were allowed to lay eggs in controlled conditions of humidity and temperature, and reproductive parameters were measured and analyzed. Hosts and tick larvae were tested for the presence of Babesia spp. using species-specific qPCR assays. Tick infestation was not observed in adult buffaloes. However, buffalo and cattle calves were equally infested, although the larval survival rate was higher in cattle calves than in buffalo calves. All larval pools (31) obtained from the adult female ticks were positive for B. bovis, whereas only 68% (21/31) was positive for B. bigemina. Among the 10 larval pools negative for B. bigemina, three proceeded from adult females fed on Babesia-negative buffaloes. The other seven pools were from Babesia-positive animals, three from cattle and four from buffalo calves. Babesia infection levels in tick larvae, quantified by qPCR, were similar in female ticks fed on buffalo and bovine calves. We conclude that water buffalo can sustain tick vector populations and support Babesia infection in levels high enough as to be infective for ticks. Our results also validated the hypothesis that adult female ticks fed on buffalo can transmit the pathogens B. bovis and B. bigemina to their offspring. Nevertheless, further laboratory studies are needed to address the question of whether the transovarial transmission of Babesia occurs in the following settings: (1) When adult females are infected previous to the feeding on the buffalo or/and (2) when the adult females acquire the infection while feeding on the buffalo.

scholarly journals A variant of the pyroantimonate technique suitable for localization of calcium in ovarian tissue.

1979 ◽  
Vol 27 (6) ◽  
pp. 1017-1028 ◽  
Author(s):  
B S Weakley
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Lipid Droplets ◽  
Microprobe Analysis ◽  
Smooth Endoplasmic Reticulum ◽  
Ovarian Tissue ◽  
Follicle Cells ◽  
Fixation Time ◽  
X Ray ◽  
Cytoplasmic Processes

Osmium-pyroantimonate solutions for the precipitation of cations are unsuitable for use with delicate mammalian oocytes. A variant of the pyroantimonate technique employing a mixture of pyroantimonate and glutaraldehyde has been found to give successful and repeatable results if a fixation time of 4 hr is used. Calcium-containing antimonate precipitates were localized principally in nuclei, smooth endoplasmic reticulum, Golgi apparatus, mitochondria, and cytoplasmic processes of both oocytes and follicle cells, and along the plasma membrane in small oocytes. Deposits were also concentrated around the periphery of lipid droplets in the follicle cells. The presence of calcium in the precipitates was confirmed by x-ray microprobe analysis.

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