Development of the vitellaria of the liver fluke, Fasciola hepatica in the rat host

Parasitology ◽  
2001 ◽  
Vol 123 (5) ◽  
pp. 509-518 ◽  
Author(s):  
M. W. ROBINSON ◽  
L. M. COLHOUN ◽  
I. FAIRWEATHER ◽  
G. P. BRENNAN ◽  
J. H. WAITE
Keyword(s):  
Fasciola Hepatica ◽  
Liver Parenchyma ◽  
The Body ◽  
Adult Fluke ◽  
Shell Protein ◽  
Body Development ◽  
Transmission Electron ◽  
Electron Immunocytochemistry ◽  
Vitelline Cells ◽  
Shell Globule

The development of the vitellaria of Fasciola hepatica within the liver of its rat host was studied by means of whole-mount stained preparations and transmission electron microscopy, together with light and electron immunocytochemistry using an antibody to vitelline protein B, an eggshell precursor protein synthesized by F. hepatica. No vitelline cells could be identified in flukes recovered from the liver parenchyma, by any of the methods used. In contrast, follicles were present in flukes at the earliest time of recovery from the bile duct, namely, 5 weeks 3 days post-infection. The vitellaria in these flukes formed a row of small follicles on either side of the body. Development of the follicles was rapid: by 6 weeks 3 days, the vitellaria resembled those in the adult fluke and eggs were present in the uterus. Immunolabelling was confined to the shell protein globules in the vitelline cells, confirming the packaging of the eggshell protein within the shell globule clusters.

Disruption of vitellogenesis and spermatogenesis by triclabendazole (TCBZ) in a TCBZ-resistant isolate of Fasciola hepatica following incubation in vitro with a P-glycoprotein inhibitor

Parasitology ◽  
2014 ◽  
Vol 141 (8) ◽  
pp. 1064-1079 ◽  
Author(s):  
J. SAVAGE ◽  
M. MEANEY ◽  
G. P. BRENNAN ◽  
E. HOEY ◽  
A. TRUDGETT ◽  
...  
Keyword(s):  
Fasciola Hepatica ◽  
Resistant Isolate ◽  
Drug Efflux ◽  
Shell Protein ◽  
P Glycoprotein ◽  
Transmission Electron ◽  
Drug Efflux Pumps ◽  
Vitelline Cells ◽  
Study Support

SUMMARYA study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant fluke isolate was used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R(+)-VPL]. In the first experiment, flukes were initially incubated for 2 h in R(+)-VPL (100 μm), then incubated in R(+)-VPL+triclabendazole sulphoxide (TCBZ.SO) (50 μg mL−1, or 133·1 μm) until flukes ceased movement (at 9 h post-treatment). In a second experiment, flukes were incubated in TCBZ.SO alone and removed from the incubation medium following cessation of motility (after 15 h). In the third experiment, flukes were incubated for 24 h in R(+)-VPL on its own. Changes to the testis tubules and vitelline follicles following drug treatment and following Pgp inhibition were assessed by means of light microscope histology and transmission electron microscopy. Incubation of the Sligo isolate in either R(+)-VPL or TCBZ.SO on their own had a limited impact on the morphology of the two tissues. Greater disruption was observed when the drugs were combined, in terms of the block in development of the spermatogenic and vitelline cells and the apoptotic breakdown of the remaining cells. Sperm formation was severely affected and abnormal. Large spaces appeared in the vitelline follicles and synthesis of shell protein was disrupted. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.

Fasciola hepatica: the effect of the microtubule inhibitors colchicine and tubulozole-C on the ultrastructure of the adult fluke

Parasitology ◽  
1993 ◽  
Vol 107 (3) ◽  
pp. 297-309 ◽  
Author(s):  
A. W. Stitt ◽  
I. Fairweather
Keyword(s):  
Fasciola Hepatica ◽  
Colchicine Treatment ◽  
Type I ◽  
Adult Fluke ◽  
Basal Region ◽  
Intermediate Type ◽  
Microtubule Inhibitors ◽  
Transmission Electron ◽  
Vitelline Cells

SummaryThe effect of the microtubule inhibitors coichicine (1×10−3 M) and tubulozole-C(1×10−6 M) on the ultrastructure of adult Fasciola hepatica has been determined in vitro by transmission electron microscopy (TEM), using both intact flukes and tissue-slice material. With colchicine treatment, the apical membrane of the tegument became increasingly convoluted and blebbed, while accumulations of T1 secretory bodies occurred in the basal region of the syncytium, leading to progressively fewer secretory bodies in the syncytium. In the tegumental cells there were distinct accumulations of T1 secretory bodies around the Golgi complexes, which remained active for up to 12 h incubation. Tubulozole-treated flukes showed more severe effects, with initial accumulations of secretory bodies, both at the tegumental apex and base. This was followed in the later time-periods by the sloughing of the tegumental syncytium. In the underlying tegumental cells, the granular endoplasmic reticulum (GER) cisternae were swollen and disrupted, becoming concentrated around the nucleus. The Golgi complexes were dispersed to the periphery of the cells and gradually disappeared from the cytoplasm. After treatment with both drugs, the cell population in the vitelline follicles was altered, with an abnormally large proportion of stem cells and relatively few intermediate type I cells. The nurse cell cytoplasm became fragmented and was no longer in contact with the vitelline cells, while the shell globule clusters within the intermediate type 2 and mature cells were loosely packed. In the mature vitelline cells, ‘yolk’ globules and glycogen deposits became fewer than normal and lipid droplets were observed. The results are discussed in relation to the different modes of action of the two drugs and potential significance of this to anthelmintic (benzimidazole) therapy.

Physiological and morphological effects of genistein against the liver fluke, Fasciola hepatica

Parasitology ◽  
2008 ◽  
Vol 135 (10) ◽  
pp. 1189-1203 ◽  
Author(s):  
E. TONER ◽  
G. P. BRENNAN ◽  
K. WELLS ◽  
J. G. McGEOWN ◽  
I. FAIRWEATHER
Keyword(s):  
Structural Changes ◽  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Somatic Muscle ◽  
Shell Protein ◽  
Transmission Electron ◽  
Short Time Span ◽  
Vitelline Cells ◽  
Short Time

SUMMARYA study has been carried out to determine the activity of genistein against adult liver fluke, Fasciola hepatica. Flukes were incubated in vitro in genistein at a concentration of 0·27 mg/ml (=1 mm). They ceased to move after 3 h, at which point the experiment was terminated and the specimens prepared for examination by scanning and transmission electron microscopy. Surface changes to the flukes comprised swelling and blebbing, especially in the posterior region of the flukes, and there was particular disruption to the spines, accompanied by some spine loss. Fine structural changes to the tegumental syncytium indicated an accelerated release of secretory bodies at the surface, but a reduction in their production within the cell bodies. Autophagic activity was evident in the tegumental cells, a phenomenon that was also observed in the gastrodermal cells. Disruption to the testis and vitelline follicles was severe, with an apparent block in the normal developmental sequence of the spermatogenic and vitelline cells, respectively. Shell protein production by the vitelline cells was also disrupted. In separate experiments, somatic muscle strips were exposed to concentrations of genistein ranging from 1 μm to 1 mm. There were statistically significant increases in the frequency and/or amplitude of muscle contractions at concentrations of 10 μm, 100 μm and 1 mm. The results suggest that genistein is capable of causing severe morphological and neuromuscular disruption to adult flukes in vitro over a short time-span.

Observations on the mechanism of eggshell formation in the liver fluke, Fasciola hepatica

Parasitology ◽  
1998 ◽  
Vol 116 (6) ◽  
pp. 555-567 ◽  
Author(s):  
L. M. COLHOUN ◽  
I. FAIRWEATHER ◽  
G. P. BRENNAN
Keyword(s):  
Fasciola Hepatica ◽  
Calcium Ionophore ◽  
Phenol Oxidase ◽  
Oxidase Inhibitor ◽  
Similar Process ◽  
Eggshell Formation ◽  
Shell Protein ◽  
Combination Treatments ◽  
Tanning Process ◽  
Vitelline Cells

A mechanism for eggshell production in Schistosoma mansoni has been proposed (Wells & Cordingley, 1991), and suggests that the release of eggshell protein globules from the vitelline cells occurs under alkaline conditions within the ootype followed by their subsequent fusion to form the eggshell. Fusion and tanning of these components produces eggshell which autofluoresces. The present study was carried out to determine whether a similar process operates in Fasciola hepatica. A number of drug treatments were used to disrupt key steps in the maturation of vitelline cells. Treatment with the calcium ionophore lasalocid (1×10−5m) led to the premature release of eggshell globules from the vitelline cells but not their fusion. Incubation in monensin (1×10−6m), a sodium ionophore and ammonium chloride (NH4Cl) (5×10−2m), a weak base, resulted in the premature fusion of eggshell protein globules within the vitelline cells and premature tanning of the eggshell protein material. The copper-containing enzyme, phenol oxidase, is thought to be involved in the tanning process during the production of eggs. Diethyldithiocarbamate (DDC, 1×10−3m) is a phenol oxidase inhibitor and treatment with this compound, in combination treatments with monensin and NH4Cl, prevented fusion of the vitelline cell globules and tanning of the shell protein material. The results of the study suggest that the mechanism for eggshell formation in F. hepatica is similar to that proposed for S. mansoni and may be common to other trematodes as well.

Fine structure of the vitteline cells in the cestode Proteocephalus longicollis (proteocephalidea)

1978 ◽  
Vol 36 (2) ◽  
pp. 442-443
Author(s):  
Z. Swiderski ◽  
R. D. Eklu-natey ◽  
L. Subilia ◽  
H. Huggel
Keyword(s):  
Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Secretory Activity ◽  
Granular Endoplasmic Reticulum ◽  
Secretory Cells ◽  
Cytoplasmic Matrix ◽  
Shell Protein ◽  
Vitelline Cells ◽  
Shell Globule ◽  
Spherical Nuclei

The mature vitelline cells of Proteocephalus longicollis (Zeder, 1800) are ovoid or spherical and measure about 30μm in diameter. They represent the holocrine type of secretory cells.The spherical nuclei, about 10μm in diameter, are localized in the central part of the cell. They contain more or less prominent nucleoli enclosed in the moderately electrondense nucleoplasm (Fig. 1).The cytoplasm (Fig. 2, 3, 4) is packed with numerous shell globules of heterogenous type, large lipid droplets, and a few glycogen islands composed mainly of α-glycogen rosettes.The remaining granular cytoplasmic matrix (Fig. 3, 4) contains: (a) numerous polysomes, (b) cysternae of granular endoplasmic reticulum, (c) several mitochondria, and (d) extended Golgi regions, composed of vesicles of different sizes and density.The extensive development of granular endoplasmic reticulum (GER) and Golgi complexes indicates high secretory activity of these cells. Both Golgi and GER are evidently engaged in shell globule formation and are considered therefore to function as the shell-protein producing units

The effect of the sulphoxide metabolite of triclabendazole (‘Fasinex’) on the tegument of mature and immature stages of the liver fluke, Fasciola hepatica

Parasitology ◽  
1994 ◽  
Vol 108 (5) ◽  
pp. 555-567 ◽  
Author(s):  
A. W. Stitt ◽  
I. Fairweather
Keyword(s):  
Liver Fluke ◽  
Fasciola Hepatica ◽  
Ultrastructural Changes ◽  
Adult Fluke ◽  
Immature Stages ◽  
The Novel ◽  
Tissue Slices ◽  
Transmission Electron ◽  
Time Periods

SummaryThe effects of the novel benzimidazole, triclabendazole (TCBZ) (‘Fasinex’, Ciba-Geigy), in its active sulphoxide metabolite form (TCBZ-SX), on the tegumental ultrastructure of Fasciola hepatica were determined in vitro by transmission electron microscopy (TEM), using both intact flukes and tissue-slice material. At a concentration of 15 µ/ml, the tegument of the whole adult fluke showed ultrastructural changes only after prolonged time-periods, with vacuolation at the base of the syncytium and accumulation of T2 secretory bodies in the tegumental cells. At a concentration of 50 µ/ml, with both whole flukes and tissue-slices, the tegument appeared extremely abnormal with accumulation of secretory bodies towards the base of the syncytium. With longer incubation times, the tegument was completely sloughed away and the tegumental cells became synthetically inactive. The tegument of the 3-week-old juvenile became progressively convoluted at the apex, while in the basal regions there was severe vacuolation. In the tegumental cells, there were accumulations of T1 secretory bodies. These results confirm TCBZ as a potent fasciolicide, being very effective in disrupting the fluke tegument. They may go some way to explain the mode of action of this important fasciolicide.

Otoconia formation in the chick embryo

1983 ◽  
Vol 41 ◽  
pp. 572-573
Author(s):  
C.D. Fermin ◽  
M. Igarashi
Keyword(s):  
Chick Embryo ◽  
Inner Ear ◽  
Gallus Domesticus ◽  
The Body ◽  
Abnormal Behavior ◽  
Intensive Study ◽  
Basic Fuchsin ◽  
Gestational Period ◽  
Sensory Epithelia ◽  
Transmission Electron

Otoconia are microscopic geometric structures that cover the sensory epithelia of the utricle and saccule (gravitational receptors) of mammals, and the lagena macula of birds. The importance of otoconia for maintanance of the body balance is evidenced by the abnormal behavior of species with genetic defects of otolith. Although a few reports have dealt with otoconia formation, some basic questions remain unanswered. The chick embryo is desirable for studying otoconial formation because its inner ear structures are easily accessible, and its gestational period is short (21 days of incubation).The results described here are part of an intensive study intended to examine the morphogenesis of the otoconia in the chick embryo (Gallus- domesticus) inner ear. We used chick embryos from the 4th day of incubation until hatching, and examined the specimens with light (LM) and transmission electron microscopy (TEM). The embryos were decapitated, and fixed by immersion with 3% cold glutaraldehyde. The ears and their parts were dissected out under the microscope; no decalcification was used. For LM, the ears were embedded in JB-4 plastic, cut serially at 5 micra and stained with 0.2% toluidine blue and 0.1% basic fuchsin in 25% alcohol.

Images and Applications of Ion Explosion Spike Pits

1990 ◽  
Vol 48 (1) ◽  
pp. 584-585
Author(s):  
P. Fraundorf ◽  
J. Tentschert
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Bulk Material ◽  
Coulomb Repulsion ◽  
The Body ◽  
Atomic Scale ◽  
Early Solar System ◽  
Transmission Electron ◽  
Nuclear Particle ◽  
Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

Fin Level Defect Isolation Inside a FinFET Using Electron Beam Alteration of Current Flow

2017 ◽  
Author(s):  
H.J. Ryu ◽  
A.B. Shah ◽  
Y. Wang ◽  
W.-H. Chuang ◽  
T. Tong
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Focused Ion Beam ◽  
Current Flow ◽  
Ion Beam ◽  
The Body ◽  
Complete Understanding ◽  
Root Cause ◽  
Transmission Electron ◽  
Defect Isolation

Abstract When failure analysis is performed on a circuit composed of FinFETs, the degree of defect isolation, in some cases, requires isolation to the fin level inside the problematic FinFET for complete understanding of root cause. This work shows successful application of electron beam alteration of current flow combined with nanoprobing for precise isolation of a defect down to fin level. To understand the mechanism of the leakage, transmission electron microscopy (TEM) slice was made along the leaky drain contact (perpendicular to fin direction) by focused ion beam thinning and lift-out. TEM image shows contact and fin. Stacking fault was found in the body of the silicon fin highlighted by the technique described in this paper.

scholarly journals Reproductive biology, embryonic development and matrotrophy in the phylactolaemate bryozoan Plumatella casmiana

2021 ◽  
Author(s):  
Julian Bibermair ◽  
Andrew N. Ostrovsky ◽  
Andreas Wanninger ◽  
Thomas Schwaha
Keyword(s):  
Embryonic Development ◽  
Embryo Sac ◽  
The Body ◽  
Transcellular Transport ◽  
Cell Contacts ◽  
Transmission Electron ◽  
Distal Side ◽  
Early Embryos ◽  
Mesoderm Formation ◽  
Cytoplasmic Processes

AbstractBryozoa is a phylum of aquatic, colonial suspension-feeders within the Lophotrochozoa. In the Phylactolaemata embryonic development occurs in an internal brood sac on the body wall accompanied by extraembryonic nutrition. Owing to previous contradictive descriptions, many aspects of their sexual reproduction require restudy. Consequently, this study analyses embryogenesis of the freshwater bryozoan Plumatella casmiana by serial sections, 3D reconstruction and transmission electron microscopy. Early embryos cleave and soon develop into blastulae with a small central cavity. The mesoderm forms by delamination starting from the distal side towards the proximal end. In later embryos two polypides form on the posterior side that ultimately will be covered by a ciliated mantle in the larva. Embryos increase in size during development and form temporary cell contacts to the embryo sac. Mesodermal cells of the embryo sac show signs of transcellular transport indicating that embryos are nourished by transferring nutrients from the maternal coelom towards the brood cavity. This study clarifies several details such as mesoderm formation and the onset of bud development. Embryos are connected to their respective embryo sacs by a variety of temporary cytoplasmic processes formed by both tissues during embryogenesis, including a ‘placental’ ring zone. Although ultrastructural data of these cell contacts are not entirely conclusive about their function, we suggest that embryos absorb nutrients via the entire surface. The close opposition of embryos to the embryo sac implies placentation as matrotrophic mode in phylactolaemate bryozoans, with embryo sacs acting as placental analogues.

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