Development and ultrastructure of the marine, parasitic oomycete, Lagenisma coscinodisci (Lagenidiales): encystment of primary zoospores

1978 ◽  
Vol 56 (11) ◽  
pp. 1309-1314 ◽  
Author(s):  
E. Schnepf ◽  
G. Deichgräber ◽  
G. Drebes
Keyword(s):  
Cyst Wall ◽  
Developmental Stages ◽  
Wall Layer ◽  
Dense Layer ◽  
Cytoskeletal Elements ◽  
Primary Cyst

The primary zoospores of Lagenisma contain many peripheral "encystment vesicles." They disappear when the primary cyst wall is formed. The primary cyst wall consists of a 6-nm-thick, electron-dense layer and is secreted in less than 1 s. Ten seconds later, the flagella are retracted in the "straight-in way" within 3–4 s. The cyst bears spines which initially are filled with cytoplasm. They do not seem to contain cytoskeletal elements and possibly are shaped by a locally restricted extension of the cytoplasm and the cyst wall when the latter is formed. Later on, a secondary, inner, thicker fibrillar cyst wall layer is secreted. In contrast with other developmental stages studied hitherto, the vegetative primary cyst contains microbody-like structures.

Sarcocystis wapiti sp. nov. from the North American wapiti (Cervus elaphus)

1982 ◽  
Vol 60 (5) ◽  
pp. 881-888 ◽  
Author(s):  
Clarence A. Speer ◽  
J. P. Dubey
Keyword(s):  
Small Intestine ◽  
Cervus Elaphus ◽  
Cyst Wall ◽  
Canis Latrans ◽  
Canis Familiaris ◽  
Domestic Cat ◽  
The North ◽  
Muscle Tissues ◽  
Infected Meat ◽  
Primary Cyst

Sarcocystis wapiti sp. nov. (Eimeriina: Sarcocystidae) is described as a heteroxenous coccidian with dogs (Canis familiaris) and coyotes (Canis latrans) as the final hosts and wapiti (Cervus elaphus) as the natural intermediate host. Sarcocysts in various muscle tissues of the wapiti were micro- to macroscopic, had a thin primary cyst wall and septa, and measured 652 × 322 μm. Sarcocysts contained numerous bradyzoites that were 16.1 × 2.4 μm and few metrocytes that were 11.2 × 4.6 μm. Ten days after ingesting Sarcocystis-infected wapiti meat, a dog and a coyote began passing oocysts and sporocysts in their feces; a domestic cat did not pass oocysts or sporocysts after ingesting infected meat from the same animal. Sporulated oocysts measured 20.3 × 15.6 μm; sporocysts were 15.9 × 10.6 μm. Twelve days after ingesting wapiti meat, oocysts of S. wapiti were found in the lamina propria of the distal one-third of the villi of the small intestine of the coyote. Bradyzoites were found in digests of muscle tissue of 58 of 65 wapiti.

Description of a species of Sarcocystis (Apicomplexa: Sarcocystidae), a parasite of the northern saw-whet owl, Aegolius acadicus, and experimental transmission to deer mice Peromyscus maniculatus

1988 ◽  
Vol 66 (10) ◽  
pp. 2118-2121 ◽  
Author(s):  
Rolando H. Espinosa ◽  
Mauritz C. Sterner ◽  
John A. Blixt ◽  
Richard J. Cawthorn
Keyword(s):  
Cyst Wall ◽  
Skeletal Muscles ◽  
Granular Layer ◽  
Peromyscus Maniculatus ◽  
Deer Mice ◽  
Thin Wall ◽  
Experimental Transmission ◽  
Aegolius Acadicus ◽  
Dose Levels ◽  
Primary Cyst

Sporocysts of Sarcocystis were recovered from the intestinal mucosa of a northern saw-whet owl (Aegolius acadicus). Sporocysts measured 12.0 × 9.7 μm (9.6–14.0 × 8.0–12.0 μm; n = 100). Doses of 0, 500, and 2500 sporocysts were administered orally to five deer mice (Peromyscus maniculatus) and five Swiss-Cox white mice (Mus musculus) At necropsy, 28 days postinoculation, deer mice administered 500 and 2500 sporocysts had sarcocysts in skeletal muscles and cardiac muscle. White mice were negative at all dose levels. Sarcocysts had a thin wall (< 1 μm) that consisted of a primary cyst wall and a coarse granular layer composed of 36.6 nm granules (25.6–51.2 nm; n = 11). Thickness of the primary cyst wall was 62.5 nm (38.4–116.1 nm; n = 10). Metrocytes were 2.3 × 1.7 μm (1.5–3.5 × 1.2–2.5 μm; n = 25). Bradyzoites were 5.2 × 1.1 μm (4–7 × 1–2 μm; n = 25).

Primary Cyst Wall

2016 ◽  
pp. 2250-2253
Author(s):  
Heinz Mehlhorn
Keyword(s):  
Cyst Wall ◽  
Primary Cyst

Ultrastructure of sporodochium and conidium development in the anamorphic fungus Epicoccum nigrum

2005 ◽  
Vol 83 (10) ◽  
pp. 1354-1363 ◽  
Author(s):  
C.W. Mims ◽  
E.A. Richardson
Keyword(s):  
Basal Cell ◽  
Apical Cell ◽  
Outer Wall ◽  
Wall Layer ◽  
Dense Layer ◽  
Epicoccum Nigrum ◽  
Transparent Layer ◽  
Transmission Electron ◽  
Anamorphic Fungus ◽  
Agar Surface

Scanning and transmission electron microscopy were used to examine sporodochium and conidium development in Epicoccum nigrum Link. Each sporodochium, a slightly raised mass of hyphae consisting of a pseudoparenchymous stroma covered with muriform conidia, arose from a group of loosely packed hyphae that formed on the agar surface. Conidiophores developed from the surface of the stroma. Each possessed a two-layered wall consisting of an inner electron transparent layer and an outer electron dense layer. Most conidiophores consisted of only two cells, the apical of which became swollen and gave rise to a solitary conidium initial in a holoblastic fashion. This initial enlarged and became divided into a smaller basal cell and a larger apical cell by a transverse septum. While the basal cell did not divide further, the apical cell became divided into numerous cells as the result of the formation of longitudinal and transverse septa. As a conidium matured the electron transparent inner layer of its wall thickened while the surface of its electron dense outer wall layer became transformed into small wart-like surface ornaments. Conidium secession was schizolytic and involved a transverse splitting of the septum separating the basal cell of a conidium from its conidiophore. The end of the basal cell and the tip of the conidiophore became rounded off during conidium secession.

Developmental changes in the tegument of four microphallid metacercariae in their second (crustacean) intermediate hosts

1996 ◽  
Vol 70 (3) ◽  
pp. 201-210 ◽  
Author(s):  
K.V. Galaktionov ◽  
I.I. Malkova ◽  
S.W.B. Irwin ◽  
D.H. Saville ◽  
J.G. Maguire
Keyword(s):  
Cyst Wall ◽  
Growth And Development ◽  
Secretory Granules ◽  
Developmental Changes ◽  
Intermediate Hosts ◽  
Cyst Production ◽  
Developed Surface ◽  
Parenchymal Cells ◽  
Progressive Accumulation ◽  
Primary Cyst

AbstractThe morphology of the tegument of four microphallid metacercariae from the stage of invasive cercariae to their maturation as encysted metacercariae inside their crustacean second intermediate hosts is described. The tegument of the metacercariae developed surface lamellae and projections which, along with coated vesicles in the surface syncytium, indicated that the tegument had an absorptive function. The disappearance of secretory granules from the tegument at the same time as the appearance of the first cyst wall suggested that the tegument had a role in primary cyst production. Following this, the metacercariae continued to grow and seemingly retained their absorptive ability. The tegument was also involved in the transport of material into the perimetacercarial lumen prior to its eventual inclusion in the developing inner cyst layers. It appeared that this material originated in tegumental cells located amongst the parenchymal cells beneath the tegumental syncytial layer. On completion of the secondary cyst layers there was a gradual degeneration of structures associated with absorption and a progressive accumulation of dense discoid granules traceable to underlying tegumental cells. All four microphallid species (Maritrema arenaria,M. subdolum,Levinseniella brachysomaandMicrophallus claviformis) demonstrated the same developmental pattern but the period spent in each stage differed depending on the time spent migrating to encystment sites. The pattern of tegumental development described is thought to be applicable to all microphallid metacercariae and possibly to other metacercariae which undergo growth and development in their second intermediate hosts.

scholarly journals Morphological and morphometric features of nematode-cysts in Gymnotus inaequilabiatus liver in the Brazilian Pantanal

2017 ◽  
Vol 26 (3) ◽  
pp. 285-291 ◽  
Author(s):  
Gizela Melina Galindo ◽  
Robson Andrade Rodrigues ◽  
Sandriely Fernanda Marcondes ◽  
Priscilla Soares ◽  
Luiz Eduardo Roland Tavares ◽  
...  
Keyword(s):  
Cyst Wall ◽  
Morphological Characteristics ◽  
Paratenic Host ◽  
Liver Parenchyma ◽  
Wall Layer ◽  
Hepatic Tissue ◽  
Hepatosomatic Index ◽  
Histopathological Analysis ◽  
Paraguay River ◽  
Collagen Layer

Abstract The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River, Corumbá, Brazil, were used. The number of nematode-cysts was determined in 79 livers and 25 of them randomly selected for histopathological analysis and morphometric measures of nematode-cysts (mean diameter, thickness of collagen layer, and cyst-wall layer). The percentage of cysts with MMCs on the periphery and density in the liver parenchyma was estimated. The average number of macroscopic cysts was of 48.7 ± 2.78. Granulomatous reaction was observed surrounding the cysts. Diameter, collagen layer and cyst-wall measurements were 293.0 ± 75.18 (µm), 17.72 ± 6.01 (µm) and 12.21 ± 9.51 (µm), respectively. The number of nematode-cysts was correlated with hepatosomatic index, (r=0.26, P<0.05). Collagen layer was correlated with cyst diameter (r=0.62, P<0.01). Pericystic and parenchymatous MMCs were moderately (r=0.48) and highly (r=0.90) correlated with nematode-cysts number. Morphological characteristics of hepatic tissue and cysts-nematodes measures suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage.

Ultrastructural studies of primary spores of Conidiobolus, Erynia, and related Entomophthorales

1989 ◽  
Vol 67 (9) ◽  
pp. 2576-2589 ◽  
Author(s):  
J. P. Latgé ◽  
D. F. Perry ◽  
M. C. Prévost ◽  
R. A. Samson
Keyword(s):  
Outer Layer ◽  
Germ Tube ◽  
Spore Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Dense Layer ◽  
Nuclear Ultrastructure ◽  
Ultrastructural Studies ◽  
Thin Electron ◽  
Definition Of

Wall development during primary spore formation, discharge, and germination of Entomophthorales is emphasized in ultrastructural studies of Conidiobolus, Entomophaga, Neozygites, and Erynia. In the fungi examined, spore and sporophore walls consist of a thick, electron-translucent inner layer and a thin, electron-dense outer layer. During spore formation, cytoplasm of the supporting sporophore cell migrates into the spore initial. As the former cell empties, a septum develops. Discharge is caused by inversion of the papillum, which lacks the electron-dense layer. Only in Erynia did the two spore wall layers separate upon impact. Intracytoplasmic organization of the primary spore is typical of the Zygomycotina; the morphology of organelles was characteristic of species, whereas nuclear ultrastructure was consistent within genera. Conidiobolus nuclei have a prominent nucleolus that lacks heterochromatin, in contrast with the other genera where large patches of heterochromatin were observed. Upon germination, no rupture of the spore outer layer was observed other than at points of germ tube emergence. The germ tube wall was continuous with the inner spore wall layer. The results are discussed in reference to Entomophthorales taxonomy and definition of the terms conidium and monosporous sporangiolum.

Formation of the cyst wall and related changes in the structure of the tegument ofBucephalus haimeanus(Lacaze-Duthiers, 1854) during its metamorphosis from the cercarial to the metacercarial stage

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 47-59 ◽  
Author(s):  
J. C. Higgins
Keyword(s):  
Cyst Wall ◽  
Post Infection ◽  
Wall Layer ◽  
Secretory Vesicles ◽  
Hepatic Cells ◽  
Tegumental Cell ◽  
Sensory Cilia ◽  
Complete Breakdown ◽  
Fibrous Cyst ◽  
Layer Characteristic

SUMMARYThe formation of the cyst wall surroundingBucephalus haimeanusand the related changes in the parasite tegument during its metamorphosis from the cercarial to the metacercarial stage have been investigated by means of experimental infections inGobiusculus flavescens. The initial fibrous cyst wall is formed from secretions produced by both the anterior gland cells and the tegument of the parasite. These secretions gradually become compacted against the surrounding hepatic cells until by the 20–30th day post-infection the 3-zoned inner layer, characteristic of the fully developed cyst wall, is formed. Hepatic cells immediately adjacent to this inner cyst wall layer are disrupted by the arrival of the metacercaria and form the middle vacuolated layer. As the metacercaria grows, the cyst increases in size causing still further hepatic cells to become flattened and incorporated into the cyst structure forming the outer nucleated layer. The structure of the cercarial tegument is described. Development of the metacercarial tegument is accomplished by the sequential movement of secretory vesicles from tegumental cell bodies into the outer cytoplasmic tegument. Vesicles of the types V. 1–5 are released from the outer cytoplasmic tegument, resulting in an almost complete breakdown of this layer prior to its replacement by the tegument of the fully developed metacercaria. The latter is characterized by the V. 6–9 type vesicles, dorso-ventrally flattened spines which terminate in 5–7 digits and by sensory cilia.

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