Coccidians in the liver and testis of the herring Clupea harengus L.

1984 ◽  
Vol 62 (3) ◽  
pp. 480-493 ◽  
Author(s):  
Carol M. Morrison ◽  
William E. Hawkins
Keyword(s):  
Outer Layer ◽  
Parasitophorous Vacuole ◽  
Light And Electron Microscopy ◽  
Testicular Tissue ◽  
Clupea Harengus ◽  
Hepatic Tissue ◽  
Oocyst Wall ◽  
Sporocyst Wall ◽  
Mature Fish ◽  
Host Parasite

The coccidians Goussia clupearum from liver and Eimeria sardinae from testis of herring caught in waters near Nova Scotia were studied by light and electron microscopy. Unsporulated and sporulatcd oocysts were the most frequently encountered stages. Oocyst walls of both species were thin and closely apposed to the host cell. At least a part of the oocyst wall appeared to serve also as the boundary of the parasitophorous vacuole. In G. clupearum, membranes lining parasitophorous vacuoles of various stages seemed to be involved in host–parasite nutrient transfer. Wall-forming bodies were found in the sporont of E. sardinae, and presumptive wall-forming bodies were found in the sporont of G. clupearum. The sporocyst wall of G. clupearum appeared to consist of two valves. The wall had a thick transversely striated inner layer and a thin outer layer consisting of several closely apposed membranes. The lamellated membranes extended from the outer layer. The sporocyst wall of E. sardinae was thin and consisted of three loosely organized membranes. The sporocysts of neither species had a Stieda body. Goussia clupearum, which often elicited an intense host reaction, infected 85% of mature fish whereas E. sardinae infected 90–100%. Replacement of hepatic tissue by G. clupearum could stress fish and replacement of testicular tissue by E. sardinae could reduce sperm production, thus detrimentally affecting herring stocks.

scholarly journals Effect of household bleach on the structure of the sporocyst wall of Toxoplasma gondii

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 68
Author(s):  
Aurélien Dumètre ◽  
Jitender P. Dubey ◽  
David J.P. Ferguson
Keyword(s):  
Toxoplasma Gondii ◽  
Outer Layer ◽  
Wall Layer ◽  
Cross Link ◽  
Oocyst Wall ◽  
Maclura Pomifera ◽  
Transmission Electron ◽  
Household Bleach ◽  
Sporocyst Wall ◽  
Molecular Nature

Toxoplasma gondii oocysts are responsible for food- and water-borne infections in humans worldwide. They are resistant to common chemical disinfectants, including chlorinated products, presumably due to the structure and molecular nature of the oocyst wall but also the sporocyst wall. In this study, we used fluorescence microscopy and transmission electron microscopy to characterise the structure of both the oocyst and sporocyst walls, exposed to household bleach. Bleach removed the outer layer of the oocyst wall and the outer layer of the wall of sporocysts exposed due to rupture of the oocyst wall. The loss of the outer sporocyst wall layer was associated with a decrease in its autofluorescence, which can be linked to the degradation of dityrosine cross-link proteins, and loss of Maclura pomifera lectin-reactive glycoproteins. This study suggests that the inner layers of the oocyst and sporocyst walls are the main structures responsible for the resistance of the parasite to household bleach.

Ultrastructure of the life-cycle stages of Goussia janae (Apicomplexa, Eimeriidae), with X-ray microanalysis of accompanying precipitates

1992 ◽  
Vol 70 (12) ◽  
pp. 2382-2397 ◽  
Author(s):  
Julius Lukeš ◽  
Vladimír Starý
Keyword(s):  
Life Cycle ◽  
Host Cell ◽  
Intestinal Epithelium ◽  
Parasitophorous Vacuole ◽  
Oocyst Wall ◽  
Cell Cytoplasm ◽  
X Ray ◽  
Host Cell Cytoplasm ◽  
Life Cycle Stages ◽  
Sporocyst Wall

The ultrastructural features of the life-cycle stages of Goussia janae from the intestinal epithelium of the dace Leuciscus leuciscus and chub L. cephalus are described. All merogonial, gamogonial, and early sporogonial stages were localized in the microvillar region in an intracellular and extracytoplasmic position, covered by closely apposed enterocyte and parasitophorous vacuole membranes. Two types of location in the host cell were observed: (i) a more frequent "monopodial" type with a single zone of attachment to the host-cell cytoplasm, and (ii) a "spider-like" type with several isolated zones of attachment. Merozoites were formed by either ecto- or endo-merogony. Microgamonts produced elongated biflagellate microgametes at their periphery. The oocyst wall, produced exclusively by the parasite, was formed at the end of the intracellular phase of the life cycle. Exogenous sporulation resulted in the formation of elongated sporocysts with a thin sporocyst wall bearing a longitudinal suture accompanied by a narrow membranaceous veil. In the cytoplasm and cytoplasmic and parasitophorous vacuoles of the parasite, fine, dense precipitates were present. X-ray microanalysis of these precipitates from osmicated and non-osmicated samples revealed high levels of Ca and P, indicating the possible presence of hydroxyapatite.

Description of Eimeria bubonis sp.n. (Protozoa: Eimeriidae) and Caryospora bubonis sp.n. (Protozoa: Eimeriidae) in the great horned owl, Bubo virginianus (Gmelin), of Saskatchewan

1981 ◽  
Vol 59 (2) ◽  
pp. 170-173 ◽  
Author(s):  
Richard J. Cawthorn ◽  
P. H. G. Stockdale
Keyword(s):  
New Species ◽  
Outer Layer ◽  
Polar Granule ◽  
Oocyst Wall ◽  
Bubo Virginianus ◽  
Sporocyst Residuum ◽  
Two New Species ◽  
Sporocyst Wall ◽  
Oocyst Residuum

Two new species of Eimeriidae are described from the great horned owl, Bubo virginianus (Gmelin), of Saskatchewan. The subspherical oocysts of Eimeria bubonis sp.n. are 22.8 ± 2.7 μm (18–30) long and 21.7 ± 2.4 μm (16–29) wide. The spindle-shaped sporocysts are 12.7 ± 1.1 μm (9.5–15.0) long and 7.8 ± 0.7 μm (5.8–10.0) wide. The polar granule, Steida body, and sporocyst residuum are present; the micropyle and oocyst residuum are absent. The oocyst wall is 0.8 μm thick, with a thick, clear outer layer and a thin, dark inner layer. Sporozoites, with a prominent conoid at the anterior end, are 13.1 ± 1.5 μm (10.0–16.3) long and 2.6 ± 0.3 μm (2.0–4.8) wide.The subspherical oocysts of Caryospora bubonis sp.n. are 43.9 ± 3.4 μm (38–52) long and 40.2 ± 2.8 μm (33–47) wide. The subspherical sporocysts are 26.6 ± 3.4 μm (20–33) long and 25.6 ± 2.4 μm (20–32) wide. The sporocyst residuum is present; the polar granule, Steida body, and oocyst residuum are absent. The oocyst wall is 1.1 μm thick, with a thick, clear outer layer and a thin, dark inner layer. The sporocyst wall is 0.8 μm thick with a thick, clear outer layer and a thin, dark inner layer. Sporozoites, with a prominent conoid at the anterior end, are 15.5 ± 1.9 μm (13.0–20.8) long and 2.5 ± 0.2 μm (2.3–3.0) wide.In both species, sporulation is complete in 96 h at 21 ± 2 °C.

Electron microscopy of Eimeria acervulina macrogametogony and oocyst wall formation

Parasitology ◽  
1984 ◽  
Vol 89 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R. M. Pittilo ◽  
S. J. Ball
Keyword(s):  
Electron Microscopy ◽  
Outer Layer ◽  
Morphological Changes ◽  
Parasitophorous Vacuole ◽  
Type I ◽  
Type Ii ◽  
Oocyst Wall ◽  
Eimeria Acervulina ◽  
Cytoplasmic Membranes ◽  
The Veil

SummaryMacrogametogony and the formation of the oocyst wall has been examined in Eimeria acervulina. Macrogametes develop within a parasitophorous vacuole. Within the cytoplasm can be observed wall-forming bodies of Type I (WFBI). and Type II (WFBII), a nucleus, mitochondria, canaliculi and polysaccharide granules. WFBII are unusual in possessing a membrane internal to the granular endoplasmic reticulum. Formation of the outer layer of the oocyst wall is preceded by the separation of a veil membrane, and accompanied by morphological changes in the WFBI. WFBI material is deposited between the veil-forming membrane and the two cytoplasmic membranes. A newly formed membrane divides this outer layer during its early development. The inner layer of the oocyst wall is formed from WFBII material which is deposited between the cytoplasmic limiting membranes. The outer layer of the oocyst wall consists of granular and osmiophilic parts, but the inner layer of the wall is homogenous.

Parasites as biological tags in marine fisheries research: European Atlantic waters

Parasitology ◽  
2014 ◽  
Vol 142 (1) ◽  
pp. 54-67 ◽  
Author(s):  
K. MACKENZIE ◽  
W. HEMMINGSEN
Keyword(s):  
Marine Mammals ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
Melanogrammus Aeglefinus ◽  
Ecological Group ◽  
The North ◽  
Recent Developments ◽  
Host Parasite ◽  
Mediterranean And Black Seas ◽  
Biological Tags

SUMMARYStudies of the use of parasites as biological tags for stock identification and to follow migrations of marine fish, mammals and invertebrates in European Atlantic waters are critically reviewed and evaluated. The region covered includes the North, Baltic, Barents and White Seas plus Icelandic waters, but excludes the Mediterranean and Black Seas. Each fish species or ecological group of species is treated separately. More parasite tag studies have been carried out on Atlantic herring Clupea harengus than on any other species, while cod Gadus morhua have also been the subject of many studies. Other species that have been the subjects of more than one study are: blue whiting Micromesistius poutassou, whiting Merlangius merlangus, haddock Melanogrammus aeglefinus, Norway pout Trisopterus esmarkii, horse mackerel Trachurus trachurus and mackerel Scomber scombrus. Other species are dealt with under the general headings redfishes, flatfish, tunas, anadromous fish, elasmobranchs, marine mammals and invertebrates. A final section highlights how parasites can be, and have been, misused as biological tags, and how this can be avoided. It also reviews recent developments in methodology and parasite genetics, considers the potential effects of climate change on the distributions of both hosts and parasites, and suggests host-parasite systems that should reward further research.

Potential of Eimeria sardinae (Apicomplexa: Eimeridae) Oocysts for Distinguishing between Spawning Groups and between First- and Repeat-Spawning Atlantic Herring (Clupea harengus harengus)

1987 ◽  
Vol 44 (7) ◽  
pp. 1379-1385 ◽  
Author(s):  
Sharon E. McGladdery
Keyword(s):  
Clupea Harengus ◽  
Maturity Stage ◽  
Atlantic Herring ◽  
Spawning Grounds ◽  
The Difference ◽  
Mature Fish ◽  
Clupea Harengus Harengus ◽  
Surrounding Areas ◽  
Immature Fish ◽  
Northeastern Atlantic

Prevalence of Eimeria sardinae oocysts was closely correlated with the maturity stage of the testes of Atlantic herring (Clupea harengus harengus). Prevalence was low in testes of immature fish, increased in ripe and spawning fish, and decreased in postspawning fish. No correlation was found between prevalence and age of spawning herring. The uniformly high prevalences in mature fish indicated the efficiency of transmission on the spawning grounds, where infective oocysts are released. Infection of first-spawning herring (approximately age 3) indicated that the oocysts may be dispersed to surrounding areas or immature fish may associate with spawning aggregations. Therefore, this parasite could not be used to distinguish first from repeat spawners. Prevalence oF E. sardinae peaked in May and September, and possibly in June and early July, thereby distinguishing two, and possibly three, spawning groups. A previous study indicated no correlation between maturity stage and infections by E. sardinae in northeastern Atlantic herring. The difference between the two sides of the Atlantic is attributed to greater mixing of immature and adult herring around spawning grounds and/or greater dispersal of infective oocysts from spawning grounds in the northeastern Atlantic, compared with those in the northwest.

scholarly journals Histological insight into the hepatic tissue of the Nile monitor (Varanus niloticus)

2018 ◽  
Vol 2 (3) ◽  
pp. 240-250
Author(s):  
Yasser A. Ahmed ◽  
Mohammed Abdelsabour Khalaf ◽  
Elsaysed Mohammed
Keyword(s):  
Light And Electron Microscopy ◽  
Lymphatic Vessels ◽  
Left Lobe ◽  
Hepatic Tissue ◽  
Histological Structure ◽  
Central Vein ◽  
Bile Canaliculi ◽  
Portal Area ◽  
Space Of Disse ◽  
Liver Fragments

The liver of reptiles is considered an important study model for the interaction between environment and hepatic tissue. Little is known about the histology of the liver of reptiles. The aim of the current study was to elucidate the histological architecture of the liver of the Nile monitor (Varanus niloticus). Liver fragments from the Nile monitor were collected in the summer season and processed for the light and electron microscopy. The liver of the Nile monitor was bi-lobed and the right lobe was found to be larger than the left lobe. Histological examination revealed indistinct lobulation of the liver, and the central vein, sinusoids and portal area were haphazardly organized. The hepatic parenchyma consisted of hepatocytes arranged in glandular-like alveoli or tubules separated by a network of twisted capillary sinusoids. The hepatocytes were polyhedral in shape with vacuolated cytoplasm and the nucleus was single rounded, eccentric, large and vesicular with a distinct nucleolus. The hepatocytes contained numerous lipid droplets, abundant glycogen granules and well-developed RER and mitochondria. The hepatocytes appeared to secrete into the bile canaliculi through the disintegration of their dark cytoplasm into the bile canaliculi. The space of Disse separating between the hepatocytes and sinusoids contained many recesses. The portal area contained branches of the portal vein, hepatic artery, bile duct and lymphatic vessels embedded in a connective tissue. Some non-parenchymal cells were described such as Kupffer cells, heterophils, melano-macrophages, intercalated cells, myofibroblasts in addition to the endothelium of the sinusoids. This is the first report about the histological structure of the liver of the Egyptian Nile monitor. The result presented here should be considered a baseline knowledge to compare with the pathological affections of the liver in this species.

Trophoblast transferrin and transferrin receptors in the host–parasite relationship of human pregnancy

1979 ◽  
Vol 204 (1154) ◽  
pp. 83-97 ◽  
Keyword(s):  
Iron Transport ◽  
Light And Electron Microscopy ◽  
Biological Significance ◽  
Transformed Cells ◽  
Specific Factor ◽  
Transferrin Receptors ◽  
Immunological Recognition ◽  
Parasite Relationship ◽  
Cellular Replication ◽  
Host Parasite

Transferrin and specific transferrin receptors are demonstrated on the microvillous surface of syncytiotrophoblast in human immature and term placentae by immunohistological techniques with the use of light and electron microscopy. That the distribution of transferrin is limited to the materno-foetal interface supports the hypothesis that binding of maternal transferrin to trophoblast receptors is involved in the process of iron transport to the foetus. Parallel studies with baboon placentae demonstrate the presence of trophoblast receptors which bind both baboon and human transferrin, thereby putting forward an experimental model which might be used to test the biological significance of placental transferrin receptors in primates. In addition, investigation of a large number of human cell lines shows that many transformed cells, but no normal cells (such as blood lymphocytes) or cells from primary culture (such as neonatal foreskin fibroblasts), possess the ability to bind transferrin to their membranes. These findings suggest that transferrin receptors may play important biological roles in addition to that of iron transport from mother to foetus. One such role could be the limitation of iron in intervillous spaces, thus depriving iron-requiring microorganisms of iron, hence serving as a non-specific factor of resistance for placentae. Another role for foetal transferrin receptors on trophoblasts could be to bind maternal transferrin at the materno-foetal interface, thus frustrating maternal immunosurveillance. This is similar to a mechahism used by schistosomes in the host-parasite relation where host proteins are bound by the parasite to escape immunological recognition. The presence of transferrin receptors on transformed cells suggests that this mechanism might also be employed by tumour cells. Finally, in view of previous studies which show that transferrin is required by stimulated lymphocytes to pass from the G 1 to the S phase of cellular replication, it is proposed that trophoblast transferrin receptors could limit the amount of transferrin in intervillous spaces and thus impede the proliferation and possible cytotoxicity of maternal activated lymphocytes at the materno-foetal interface.

THE CUTICLE OF THE TWO-SPOTTED SPIDER MITE, TETRANYCHUS TELARIUS (LINNAEUS) (ACARINA: TETRANYCHIDAE)

1959 ◽  
Vol 37 (5) ◽  
pp. 633-637 ◽  
Author(s):  
K. E. Gibbs ◽  
F. O. Morrison
Keyword(s):  
Electron Microscopy ◽  
Thin Layer ◽  
Outer Layer ◽  
Spider Mite ◽  
Light And Electron Microscopy ◽  
Inside Surface ◽  
Dark Staining ◽  
Two Spotted Spider Mite ◽  
Epicuticular Layer

The cuticle of T. telarius (L.) examined by light and electron microscopy and subjected to tests for chitin and lipids is shown to be a thin layer with a pattern of external ridges. It is about 1.25 microns thick measured in the troughs and twice that thickness measured at the ridges. The ridges average from 1 to 1.6 μ apart. There is no tectocuticle but an outside lipoid layer and a dark-staining non-chitinous epicuticular layer from 0.1 to 0.2 μ thick. A double-layered inner procuticle is present. The outer layer of the procuticle remains unstained in contrast to the dark-staining inner layer. The inside surface of the cuticle bears elevations or ridges opposite the external troughs. The epicuticle only is shed at molting. It bears the branched setae and over the eyes is striated, the ridges being about 0.14 microns apart. Either one or both layers of the procuticle contain chitin.

scholarly journals Ultrastructure of phagocytes and oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) infecting Crassostrea rhizophorae in Northeastern Brazil

2019 ◽  
Vol 28 (1) ◽  
pp. 97-104
Author(s):  
Themis Jesus Silva ◽  
Emerson Carlos Soares ◽  
Graça Casal ◽  
Sónia Rocha ◽  
Elton Lima Santos ◽  
...  
Keyword(s):  
Parasitophorous Vacuole ◽  
Adductor Muscle ◽  
Systematic Position ◽  
Variable Number ◽  
Northeastern Brazil ◽  
Ultrastructural Organization ◽  
Oocyst Wall ◽  
Transmission Electron ◽  
Adductor Muscles ◽  
Crassostrea Rhizophorae

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.

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