Ultrastructure and histochemistry of the tegument of juvenile paramphistomes during migration in Indian ruminants

AbstractThe tegument of juvenile Paramphistomum epiclitum and Fischoederius elongatus (Paramphistomidae: Digenea) resembles those of other digeneans. Seven types of papillae were observed, mostly on the oral and acetabular surfaces, and increase in number during migration. Also evident are two types of secretory body (T1 and T2) which are synthesized separately in tegumental cytons underlying the syncytium. Exocytosis of T2 bodies occurs at the apical membrane and appears to contribute to a fibrous glycocalyx. The tegumental syncytium lining the pharynx and acetabulum is thinner and has a higher capacity for vacuolation than the general tegument. These may represent important sites for osmoregulation. The absence of mitochondria from the tegument in migrating juveniles suggests limited involvement in energy demanding processes. Pigmentation of the subtegument is first evident in mature cercariae and is progressively eliminated during migration.

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Ultrastructural observations on the redial tegument of Paramphistomum epiclitum from the planorbid snail, Indoplanorbis exustus

Journal of Helminthology ◽

10.1017/s0022149x00014516 ◽

1992 ◽

Vol 66 (3) ◽

pp. 167-176 ◽

Cited By ~ 3

Author(s):

T. S. Dunn ◽

P. H. Dang ◽

G. Mattison ◽

R. E. B. Hanna ◽

W. A. Nizami

Keyword(s):

Outer Surface ◽

Apical Membrane ◽

Single Type ◽

Sensory Receptors ◽

Secretory Body ◽

Indoplanorbis Exustus ◽

Paramphistomum Epiclitum ◽

Single Nucleus ◽

Uptake Of Nutrients ◽

Tegumental Syncytium

ABSTRACTThe morphology of the tegument in the redia of Paramphistomum epiclitum (Digenea: Paramphistomidae) resembles that shown by most larval and adult digeneans; an outer surface syncytium is in continuity with the cytoplasm of in-sunken, nucleated cytons. Although tegumental cytons usually contain a single nucleus, some display up to six nuclei. The tegumental syncytium lining the pharynx of P. epiclitum rediae lack underlying cytons. The apical membrane of the tegument is elaborated by folds and microvilli, which presumably facilitate uptake of nutrients and/or exchange of ions involved in osmoregulation. A single type of secretory body, resulting from the fusion of smaller vesicles produced at Golgi complexes in the cytons, occurs throughout the tegument. Uniciliate sensory receptors occur in the surface syncytium particularly around the oral opening.

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Ultrastructural changes to the tegumental system and gastrodermal cells of adult Fasciola hepatica following treatment in vivo with a commercial preparation of myrrh (Mirazid)

Journal of Helminthology ◽

10.1017/s0022149x16000705 ◽

2016 ◽

Vol 91 (6) ◽

pp. 672-685 ◽

Cited By ~ 3

Author(s):

M.M.O. Abdelaal ◽

G.P. Brennan ◽

A. Abdel-Aziz ◽

I. Fairweather

Keyword(s):

Fasciola Hepatica ◽

Ultrastructural Changes ◽

Muscle Fibres ◽

Somatic Muscle ◽

Secretory Body ◽

Commercial Preparation ◽

Transmission Electron ◽

Body Production ◽

Tegumental Syncytium

AbstractAn in vivo study in the laboratory rat model has been carried out to monitor changes to the tegument and gut of adult Fasciola hepatica following treatment with myrrh (‘Mirazid’). Rats infected with the triclabendazole-resistant Dutch isolate were dosed orally with Mirazid at a concentration of 250 mg/kg and flukes recovered 2, 3 and 7 days post-treatment (pt). The flukes were processed for examination by scanning and transmission electron microscopy. A variety of changes to the external surface were observed, culminating in the sloughing of the tegumental syncytium. Internal changes to the syncytium and tegumental cell bodies were more severe and were evident from 2 days pt onwards. Swelling of the basal infolds (leading to flooding of the surface layer) and a decline in secretory body production were the major changes seen. The gastrodermal cells were less severely affected than the tegument, pointing to a trans-tegumental route of uptake for Mirazid by the fluke. Some loss of muscle fibres in the main somatic muscle layers was observed, which may be correlated with the decline in movement of flukes seen at recovery.

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Ultrastructure of the tegument of the trematode Ganeo tigrinum parasitizing the intestine of indian frogs

Journal of Helminthology ◽

10.1017/s0022149x00015297 ◽

1996 ◽

Vol 70 (2) ◽

pp. 137-142 ◽

Cited By ~ 2

Author(s):

P.N. Sharma ◽

N. Rai ◽

G.P. Brennan

Keyword(s):

Active Transport ◽

Anterior Region ◽

Secretory Body ◽

Tegumental Syncytium

AbstractThe surface tegument of G. tigrinum generally resembles that described for other digeneans. It contains surface tubercles and is covered with a glycocalyx. In the anterior region the tegument bears spines while tubular-like canals and occasional deep invaginations are present on the anteroventral surface. Two types of secretory body are present in the tegumental syncytium and produced in separate tegumental cells. Mitochondria are present in the surface syncytium, suggesting active transport occurs across the tegument in non-hibernating frogs.

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Ultrastructure of the tegument of the metacercaria ofTimoniella imbutiforme

Journal of Helminthology ◽

10.1017/s0022149x00000081 ◽

2000 ◽

Vol 74 (1) ◽

pp. 57-66 ◽

Cited By ~ 3

Author(s):

H.E.M. El-Darsh ◽

P.J. Whitfield

Keyword(s):

Basal Lamina ◽

Larval Stage ◽

The Body ◽

Secretory Body ◽

Gland Cells ◽

Normal Configuration ◽

Secretory Gland ◽

Tegumental Syncytium ◽

Somatic Muscles ◽

Sensory Endings

AbstractThe spinous body tegument of the metacercaria ofTimoniella imbutiforme(Molin, 1859) is described in detail and found to comprise an outer tegumental syncytium connected to subjacently situated subtegumentary ‘cells’. There are four types of secretory bodies in the outer syncytial layer as well as serrated overlapping spines and mitochondria. The subtegumentary ‘cells’ are characterized by the presence of four secretory body types as well as giant bodies which may be involved in the elaboration of the secretory bodies or spine material. The normal configuration of the somatic muscles ofT. imbutiformeshow that the muscular machinery necessary for activity once the larval stage becomes excysted is already in place. The sensory endings are found to be of the uniciliate type occurring in groups of up to eight in raised domes distributed over the body. Secretory gland cells are numerous and possess long ducts connected to the basal lamina of the outer syncytial layer via septate desmosomes.

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Role of PKC isozymes in water transport in toad urinary bladder

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085812 ◽

1991 ◽

Vol 49 ◽

pp. 302-303

Author(s):

A.J. Mia ◽

L.X. Oakford ◽

T. Yorio

Keyword(s):

Urinary Bladder ◽

Apical Membrane ◽

Membrane Surface ◽

Protein A ◽

Cell Types ◽

Leukemic Cells ◽

Toad Urinary Bladder ◽

Pkc Isozymes ◽

Antibody Labeling

Protein kinase C (PKC) isozymes, when activated, are translocated to particulate membrane fractions for transport to the apical membrane surface in a variety of cell types. Evidence of PKC translocation was demonstrated in human megakaryoblastic leukemic cells, and in cardiac myocytes and fibroblasts, using FTTC immunofluorescent antibody labeling techniques. Recently, we reported immunogold localizations of PKC subtypes I and II in toad urinary bladder epithelia, following 60 min stimulation with Mezerein (MZ), a PKC activator, or antidiuretic hormone (ADH). Localization of isozyme subtypes I and n was carried out in separate grids using specific monoclonal antibodies with subsequent labeling with 20nm protein A-gold probes. Each PKC subtype was found to be distributed singularly and in discrete isolated patches in the cytosol as well as in the apical membrane domains. To determine if the PKC isozymes co-localized within the cell, a double immunogold labeling technique using single grids was utilized.

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The Reliability of Retrieval-Induced Forgetting

European Psychologist ◽

10.1027/1016-9040/a000040 ◽

2012 ◽

Vol 17 (1) ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

Rosalind Potts ◽

Robin Law ◽

John F. Golding ◽

David Groome

Keyword(s):

Individual Differences ◽

Recognition Test ◽

Laboratory Tests ◽

The Other ◽

Clinical Factors ◽

Test Items ◽

T1 And T2 ◽

Test Materials ◽

Induced Forgetting

Retrieval-induced forgetting (RIF) refers to the finding that the retrieval of an item from memory impairs the retrieval of related items. The extent to which this impairment is found in laboratory tests varies between individuals, and recent studies have reported an association between individual differences in the strength of the RIF effect and other cognitive and clinical factors. The present study investigated the reliability of these individual differences in the RIF effect. A RIF task was administered to the same individuals on two occasions (sessions T1 and T2), one week apart. For Experiments 1 and 2 the final retrieval test at each session made use of a category-cue procedure, whereas Experiment 3 employed category-plus-letter cues, and Experiment 4 used a recognition test. In Experiment 2 the same test items that were studied, practiced, and tested at T1 were also studied, practiced, and tested at T2, but for the remaining three experiments two different item sets were used at T1 and T2. A significant RIF effect was found in all four experiments. A significant correlation was found between RIF scores at T1 and T2 in Experiment 2, but for the other three experiments the correlations between RIF scores at T1 and T2 failed to reach significance. This study therefore failed to find clear evidence for reliable individual differences in RIF performance, except where the same test materials were used for both test sessions. These findings have important implications for studies involving individual differences in RIF performance.

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