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.

Ultrastructural features of the tomont of Cryptocaryon irritans (Ciliophora: Prostomatea), a parasitic ciliate of marine fishes

Parasitology ◽  
2017 ◽  
Vol 144 (6) ◽  
pp. 720-729 ◽  
Author(s):  
RUI MA ◽  
XINPENG FAN ◽  
FEI YIN ◽  
BING NI ◽  
FUKANG GU
Keyword(s):  
Cell Division ◽  
Cyst Wall ◽  
Light And Electron Microscopy ◽  
Secretory Vesicles ◽  
Free Living ◽  
Cryptocaryon Irritans ◽  
Daughter Cells ◽  
Molecular Events ◽  
Cellular Metabolic Activity ◽  
Cellular Organelles

SUMMARYNumerous studies have been conducted on the cellular morphology of Cryptocaryon irritans. However, details regarding the tomont stage of its life cycle remain lacking. In this study, we investigated the morphology of the tomont stage throughout encystment and cell division using light and electron microscopy. Results showed that there was no secretion of encystation-specific secretory vesicles or extrusomes during formation of the cyst wall. Instead, the synthesis and construction of the C. irritans cyst wall materials may involve molecular events at the pellicle. The somatic cilia and the cytostome were present during encystment and covered by the newly formed cyst wall. New somatic cilia were continuously created between old cilia and showed various lengths during cell division, a process that was similar to morphogenesis in many free-living ciliates. During cell division inside the tomont, dividing daughter cells formed temporary cell chains with no oral primordia before separating from each other into dissociative tomite precursors. The process of cell division may not be accompanied by stomatogenesis, and new oral primordia in offspring cells likely formed before the dividing cell chains split into dissociative spherical tomites. Mitochondrial autophagy was observed in encysting C. irritans cells. Numerous endosymbionts and Golgi structures were observed in the tomont cytoplasm. Cellular metabolic activity in the C. irritans tomont was quite high, with large amounts of materials or cellular organelles potentially being synthesized and prepared for the following infective theront stage.

On the viability of Fasciola gigantica metacercariae ingested by Lymnaea auricularia

1988 ◽  
Vol 62 (4) ◽  
pp. 303-304 ◽  
Author(s):  
S. C. Yadav ◽  
S. C. Gupta
Keyword(s):  
Cyst Wall ◽  
Post Infection ◽  
Fasciola Gigantica ◽  
Digestive Processes

AbstractThe effect of ingestion by Lymnaea auricularia on the viability and infectivity of Fasciola gigantica metacercariae was studied. The cyst wall was unaffected by the snail's digestive processes. Two rabbits, each infected with 50 ingested metacercariae, died at 83 and 87 days post-infection. Eight and 10 immature flukes were recovered from the livers, indicating that the metacercariae had remained infective after passing through the intestine of the snail.

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.

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.

Correlated Changes Between the Golgi Apparatus and Cell Wall Formation During Sporogenesis

1967 ◽  
Vol 25 ◽  
pp. 80-81
Author(s):  
John E. Ridgway
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Electron Density ◽  
Intimate Relationship ◽  
Wall Layer ◽  
Secretory Vesicles ◽  
Cell Wall Formation ◽  
Layer I ◽  
Cell Wall Deposition

During the formation of cell wall layers of the sporocyte and spore during sporogenesis in Anthoceros fuciformis Mont., there appears to he an intimate relationship between the Golgi apparatus and cell wall deposition. As the initial sporocyte wall if formed, the cisternae of the Golgi apparatus become extensively hypertrophied and produce large vesicles which move through the cytoplasm and empty their contents through the plasma membrane to form the developing primary sporocyte wall layer (I) (Figure 1). In both methods of fixation used, a similiar electron density was observed in the contents of the Golgi cisternae, the Golgi secretory vesicles, and the components of the sporocyte wall layer-I.

scholarly journals Entamoeba histolytica Lectins Contain Unique 6-Cys or 8-Cys Chitin-Binding Domains

2002 ◽  
Vol 70 (6) ◽  
pp. 3259-3263 ◽  
Author(s):  
Katrina Van Dellen ◽  
Sudip K. Ghosh ◽  
Phillips W. Robbins ◽  
Brendan Loftus ◽  
John Samuelson
Keyword(s):  
Entamoeba Histolytica ◽  
Cyst Wall ◽  
Secretory Vesicles ◽  
Entamoeba Dispar ◽  
Binding Domains ◽  
Genes Encoding ◽  
Entamoeba Invadens

ABSTRACT The Jacob lectin, the most abundant glycoprotein in the cyst wall of Entamoeba invadens, contains five unique 6-Cys chitin-binding domains (CBDs). We identified Entamoeba histolytica and Entamoeba dispar genes encoding Jacob homologues, each of which contains two predicted 6-Cys CBDs. A unique 8-Cys CBD was found at the N termini of the E. histolytica chitinase and three other predicted lectins, called Jessie 1 to Jessie 3. The CBDs of four E. histolytica lectins (Jacob, chitinase, and Jessies 2 and 3) were expressed in secretory vesicles of transfected amebae and shown to bind to particulate chitin.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Hepatic Ultrastructure Changes Induced by Lithocholic Acid

1967 ◽  
Vol 25 ◽  
pp. 162-163 ◽  
Author(s):  
F. G. Zaki
Keyword(s):  
Endoplasmic Reticulum ◽  
Lithocholic Acid ◽  
Smooth Endoplasmic Reticulum ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Electron Microscopic ◽  
Hydropic Degeneration ◽  
Hepatic Cells ◽  
Low Protein ◽  
Microscopic Studies

Addition of lithocholic acid (LCA), a naturally occurring bile acid in mammals, to a low protein diet fed to rats induced marked inflammatory reaction in the hepatic cells followed by hydropic degeneration and ductular cell proliferation. These changes were accompanied by dilatation and hyperplasia of the common bile duct and formation of “gallstones”. All these changes were reversible when LCA was withdrawn from the low protein diet except for the hardened gallstones which persisted.Electron microscopic studies revealed marked alterations in the hepatic cells. Early changes included disorganization, fragmentation of the rough endoplasmic reticulum and detachment of its ribosomes. Free ribosomes, either singly or arranged in small clusters were frequently seen in most of the hepatic cells. Vesiculation of the smooth endoplasmic reticulum was often encountered as early as one week after the administration of LCA (Fig. 1).

Analysis of the Anterior Secretory Cells of Onchidohs Muricata (Nudibranchia)

1981 ◽  
Vol 39 ◽  
pp. 614-615
Author(s):  
Roy Skidmore
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Golgi Body ◽  
The Body ◽  
Secretory Cells ◽  
Secretory Vesicles ◽  
High Magnification ◽  
Large Numbers ◽  
Membrane Bound ◽  
Sole Of The Foot

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).

The Fine Structure of Replicating Simian Adenoviruses in LLC-MK2

1968 ◽  
Vol 26 ◽  
pp. 220-221
Author(s):  
Matias Pardo ◽  
Malcolm Slifkin ◽  
Leonard Merkow ◽  
Marie Sanchez
Keyword(s):  
Tissue Culture ◽  
Post Infection ◽  
Cesium Chloride ◽  
Longitudinal Section ◽  
Tubular Structures ◽  
Virus Particles ◽  
Ultrastructural Studies ◽  
Culture Cells ◽  
Simian Adenovirus ◽  
Infectivity Titer

The simian adenoviruses SV20, SV30 and SA7 have been found to be oncogenic in the Syrian hamster. The growth characteristics and replicative cycle of these viruses in tissue culture therefore appeared appropriate to investigate. Cesium chloride purified simian adenovirus with an infectivity titer of 100 TCID50, was inoculated into monolayers of LLC-MK2 cells. Cells were fixed in osmium tetroxide and embedded for ultrastructural studies at 1, 3, 6, 9, 18, 24, 48, 72, 120 and 192 hours post-infection.At the first hour post-infection, virus particles were adsorbed to the plasmalemma and found within the peripheral cytoplasm of many LLC-MK2 cells (Fig. 1). Although the first detection of infectious virus occurred at 14 hours and infectivity titers did not reach a maximum until 30 hours, intranuclear virus particles were observed by 3 hours in typical adenovirus crystalline array (Fig. 2) by means of electron microscopy. These typical honeycomb arrayed virus particles at 3 hours provided evidence of significant replication in approximately 5 percent of tissue culture cells examined. Simultaneously, a classical nuclear inclusion manifested by peripheral condensation of nuclear chromatin was evident by light microscopy. As early at 6 to 9 hours, unusual intranuclear concentric membranes formed “tubes” which contained linear arranged virus particles (Fig. 3). In transverse or tangential sections, these “tubes” appeared cochlear-like in shape. In longitudinal section, these intranuclear tubular structures contained individual virus particles at various stages of maturation in a linear arranged order. This arrangement resembled “peas in a pod”.

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