Neuromuscular physiology of Hymenolepis diminuta and H. microstoma (Cestoda)

Parasitology ◽  
1984 ◽  
Vol 89 (3) ◽  
pp. 567-578 ◽  
Author(s):  
C. S. Thompson ◽  
D. F. Mettrick
Keyword(s):  
Muscle Contraction ◽  
Body Wall ◽  
Neck Region ◽  
Hymenolepis Diminuta ◽  
Bathing Solution ◽  
Inhibitory Mechanisms ◽  
Neuromuscular Systems ◽  
Ionic Changes ◽  
Chloride Salts

SUMMARYThe physiology of the neuromuscular systems in Hymenolepis diminuta and H. microstoma was studied in vitro using intact, adult worm and strips of worm body wall. Intact worms were insensitive to ionic changes in the in vitro buffering system. However, strips of body wall containing longitudinal muscles were extremely sensitive to ionic manipulation. In intact worms tension generated in the strobila had two components; small brief tension peaks up to 500 mg amplitude are superimposed on larger, longer peaks of up to 1200 mg amplitude. Removal of the scolex and neck region either failed to show significant changes in tension, or showed a reduction in amplitude but not of frequency. Muscle contraction of both H. diminuta and H. microsoma were qualitatively similar. In split-worm preparations the concentration of Ca2+ in the bathing solution significantly affected both spontaneous and evoked contractions in H. diminuta and H. microstoma; the addition of CaCl2 greatly reduced the amplitude and frequency of the contractions. The chloride salts of cobalt, barium, cadmium and manganese elicited prolonged contractions of the longitudinal musculature of both H. diminuta and H. microstoma. While CoCl2 was the most effective in stimulating muscle contraction, the magnitude of the response varied with the concentration of Ca2+ in the bath. The results indicate that peripheral inhibition is extremely important in cestode motor control and that extracellular calcium ions may regulate the peripheral inhibitory mechanisms.

Repair ofHymenolepis diminutaafter complement-mediated damage

Parasitology ◽  
1989 ◽  
Vol 99 (3) ◽  
pp. 437-443 ◽  
Author(s):  
J. Andreassen ◽  
D. Hoole
Keyword(s):  
Neck Region ◽  
Regenerative Process ◽  
Hymenolepis Diminuta ◽  
Embryological Development ◽  
Rat Serum ◽  
Ultrastructural Studies ◽  
Normal Rat ◽  
Electron Lucent

SummarySeven and 56-day-oldHymenolepis diminutawere exposed to complement by incubation in 50% normal rat serum (NRS) in modified Hanks' saline. Ultrastructural studies revealed that the scolex/neck region remained relatively intact whilst in the strobila region microthrix denudation and loss of distal cytoplasm were observed. When complement-mediated damaged worms were incubated in vitro in 50% heat-inactivated normal rat serum (hiNRS) plus M199 or implanted into the duodenum of NMRI mice repair occurred, although destrobilated parasites were only foundin vivo. The regions undergoing repair contained tegumental protrusions, vesicles, large electron-lucent areas and large quantities of lipid. Microtriches were formed parallel to the parasite surface and were raised into a perpendicular position. It is suggested that the regenerative process exhibited after complement-mediated damage does not mimic totally the embryological development of the surface layer.

In vitro inhibitory mechanisms and molecular docking of 1′-S-1′-acetoxychavicol acetate on human cytochrome P450 enzymes

Phytomedicine ◽  
2017 ◽  
Vol 31 ◽  
pp. 1-9 ◽  
Author(s):  
A.K.M. Mahmudul Haque ◽  
Kok Hoong Leong ◽  
Yoke Lin Lo ◽  
Khalijah Awang ◽  
Noor Hasima Nagoor
Keyword(s):  
Cytochrome P450 ◽  
Molecular Docking ◽  
Cytochrome P450 Enzymes ◽  
Inhibitory Mechanisms ◽  
Human Cytochrome

Possible immunological damage to the tegument ofHymenolepis diminutain mice and rats

Parasitology ◽  
1975 ◽  
Vol 71 (3) ◽  
pp. 525-534 ◽  
Author(s):  
A. D. Befus ◽  
L. T. Threadgold
Keyword(s):  
Lipid Droplets ◽  
Cell Injury ◽  
Mechanical Damage ◽  
Neck Region ◽  
Host Immunity ◽  
Hymenolepis Diminuta ◽  
Intensity Of Infection ◽  
Variable Size ◽  
Abnormal Mitochondria ◽  
Worm Expulsion

Opaque or darkened areas (DA) of variable size and position occur onHymenolepis diminutain mice and rats. In mice DA normally first appear in the neck region of the worm but subsequently they appear elsewhere and increase in number until destrobilation or worm expulsion. The posterior of destrobilated worms is often darkened. In the more immunogenic infections with six cysticercoids there are more DA per worm than in infections with one cysticercoid. DA are areas of the tegument with a homogeneous increase in electron density; abnormal mitochondria; reduced granular endoplasmic reticulum, Golgi complexes and discoidal secretory bodies; and accumulation of lipid droplets. DA disappear from worms maintained for up to 4 h in Hanks' balanced salt solution and can be induced by mechanical damage to the worms.As the numbers of DA increase with the duration and intensity of infection and have similarities with types of cell injury, they are probably sites of worm pathology induced by host immunity.

In vitro Hatching of Oncospheres of Hymenolepis diminuta (Cestoda: Cyclophyllidea)

1961 ◽  
Vol 47 (5) ◽  
pp. 813 ◽  
Author(s):  
Marietta Voge ◽  
Allen K. Berntzen
Keyword(s):  
Hymenolepis Diminuta

Hymenolepis diminuta: metacestode-induced reduction in the synthesis of the yolk protein, vitellogenin, in the fat body of Tenebrio molitor

Parasitology ◽  
1996 ◽  
Vol 112 (4) ◽  
pp. 429-436 ◽  
Author(s):  
T. J. Webb ◽  
H. Hurd
Keyword(s):  
Post Infection ◽  
Fat Body ◽  
Potent Inhibitor ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Vitellogenin Synthesis ◽  
Specific Stage ◽  
Fat Bodies ◽  
Do So

SUMMARYVitellogenin synthesis by the fat body has been monitored using in vitro culture and immunoprecipitation. This system was found to be efficient for measuring vitellogenin production in both non-infected Tenebrio molitor and those infected with Hymenolepis diminuta. In fat bodies from infected beetles, vitellogenin production was decreased by up to 75% (day 24 post-infection) and, at all times investigated, vitellogenin synthesis was significantly below control levels (days 3–30 post-infection). Incubating fat bodies from control insects with isolated metacestodes indicated that this may be a direct effect by the parasite which is developmental stage-specific. Stage II, but not stage III–IV, nor heat-killed parasites could bring about this decrease in vitellogenin. In addition, these effects may be density dependent within the range of 2–20 parasites per fat body; only 2 metacestodes were necessary to cause a significant decrease. Since metacestodes do not take up vitellogenin, nor limit the amount of [14C] leucine available to the fat body for vitellogenin production, it is conceivable that the parasite produces a potent inhibitor of vitellogenin synthesis, or a molecule which induces cells within the fat body to do so.

Temporal changes in glucose and carbohydrate metabolism in the oncospheres of the cyclophyllidean tapeworm, Hymenolepis diminuta

Parasitology ◽  
1993 ◽  
Vol 106 (3) ◽  
pp. 317-325 ◽  
Author(s):  
P. W. Pappas ◽  
G. M. Durka
Keyword(s):  
Molecular Weight ◽  
Glucose Metabolism ◽  
Carbohydrate Metabolism ◽  
Glucose Absorption ◽  
Temporal Changes ◽  
Hymenolepis Diminuta ◽  
Temporal Shift ◽  
Carbohydrate Fraction ◽  
Ethanol Extracts

SUMMARYWhen incubated in vitro for 24 h, oncospheres of Hymenolepis diminuta absorb and metabolize radioactive glucose. Between 0 and 12 h post-activation, oncospheres absorb glucose, but glucose is neither metabolized into other carbohydrates nor incorporated into the ethanol-precipitable fraction (which would contain glycogen). Between 12 and 24 h post-activation glucose is incorporated into a number of higher molecular weight carbohydrates that are demonstrable in ethanol extracts of the larvae, as well as the incubation media. Furthermore, measurable amounts of radioactivity are incorporated into the ethanol-precipitable carbohydrate fraction of oncospheres. To determine if these temporal changes in carbohydrate metabolism occurred spontaneously following activation, oncospheres were pre-incubated for 12 h (0–12 h post-activation) in the absence or presence of glucose, and then transferred to media containing radioactive glucose for an additional 12 h (12–24 h post-activation). In these latter experiments, glucose absorption and metabolism between 12 and 24 h post-activation were virtually identical to glucose metabolism in oncospheres that were incubated in radioactive glucose for 0–12 h immediately following activation. Thus, these data do not support the hypothesis that the temporal shift in carbohydrate metabolism occurs spontaneously.

scholarly journals A Study of Late Ventral Body Wall Degeneration in the Embryonic Chick, with Special Reference to the Cell Cycle

2021 ◽  
Author(s):  
◽  
Peter Barwell
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Body Wall ◽  
Morphological Changes ◽  
Cell Loss ◽  
Tissue Growth ◽  
Embryonic Chick ◽  
Cell Death Pathway ◽  
Medial Migration

<p>The cell kinetics and morphological changes during late ventral body wall development of the embryonic chick were studied, particularly midline degeneration and the medial migration of lateral tissues. An histological examination of these events was undertaken, along with autoradiography to determine the duration of the cell cycle, followed by teratological studies involving the prevention of differentiative events in the cell death pathway, using BrDU and Janus B Green as agents. The effects of cell cycle blockade on rates of cell death were also examined, as was the tissues ability to express differentiative features in vitro. Ventral body wall (VBW) cell death was classified as apoptosis, and was involved in two distinct events. Medial migration of lateral tissues began at day 5 of development, with widespread VBW apoptosis being seen by day 6, limited to the original mesoderm of the region. A later precise line of apoptosis (the VBL), involving both ectodermal cells of the midline ectodermal ruffle and the underlying mesodermal cells, was observed at day 7, spreading in a rostral to caudal fashion down the embryo, appearing as the migratory lateral tissues fused in the midline body wall. Increases in the amount of cell death are matched by decreases in the MI, such that at its peak (day 7.5 of development) the cell death rate is sufficiently greater than both the cell proliferation and immigration rates that a state of negative tissue growth ensues. The histological half-life of the apoptotic bodies approximates 3.8 hours. The ability to undergo apoptosis at day 7 is dependent upon a differentiative event around day 4 of incubation, and involves signal mechanisms intrinsic to the VBW tissues. BrDU application was found to inhibit apoptotic differentiation, in contrast to Janus B Green, which had a more generalised teratogenic effect on the region as a whole. Tissue culturing experiments revealed that an ectodermal-mesodermal interaction is important in regulating the extent of mesodermal apoptosis, the ectoderm playing a maintenance role for the mesoderm. Dead cells derive from the cycling cell population, as shown by the occurrence of labelled dead cells after autoradiography, and by the prevention of apoptosis by a cell cycle blockade, and by the production of a semi-synchronised wave of apoptoses after release of this blockade. These cell blockading results further suggest that entry into the apoptotic death program requires cells to be in a particular cell cycle stage, and it seems most likely that the decision to die was made in early G1. Tissue and cell growth rates, cell loss and death rates, cell birth rates and cell immigration rates were all determined for the VBW region throughout the time period studied.</p>

scholarly journals Studies of Inhibitory Mechanisms of Propeptide-Like Cysteine Protease Inhibitors

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Bui T. T. Nga ◽  
Yuki Takeshita ◽  
Misa Yamamoto ◽  
Yoshimi Yamamoto
Keyword(s):  
Protease Inhibitors ◽  
Cysteine Protease ◽  
Cathepsin L ◽  
Cysteine Residue ◽  
Cysteine Protease Inhibitor ◽  
Inhibition Mechanism ◽  
Cysteine Protease Inhibitors ◽  
Inhibitory Potency ◽  
Inhibitory Mechanisms

Mouse cytotoxic T-lymphocyte antigen-2α (CTLA-2α), Drosophila CTLA-2-like protein (crammer), and Bombyx cysteine protease inhibitor (BCPI) belong to a novel family of cysteine protease inhibitors (I29). Their inhibitory mechanisms were studied comparatively. CTLA-2α contains a cysteine residue (C75), which is essential for its inhibitory potency. The CTLA-2α monomer was converted to a disulfide-bonded dimer in vitro and in vivo. The dimer was fully inhibitory, but the monomer, which possessed a free thiol residue, was not. A disulfide-bonded CTLA-2α/cathepsin L complex was isolated, and a cathepsin L subunit with a molecular weight of 24,000 was identified as the interactive enzyme protein. Crammer also contains a cysteine residue (C72). Both dimeric and monomeric forms of crammer were inhibitory. A crammer mutant with Cys72 to alanine (C72A) was fully inhibitory, while the replacement of Gly73 with alanine (G73A) caused a significant loss in inhibitory potency, which suggests a different inhibition mechanism from CTLA-2α. BCPI does not contain cysteine residue. C-terminal region (L77-R80) of BCPI was essential for its inhibitory potency. CTLA-2α was inhibitory in the acidic pH condition but stabilized cathepsin L under neutral pH conditions. The different inhibition mechanisms and functional considerations of these inhibitors are discussed.

Characterization in vitro of H+ secretion and H+:Na+ exchange by an organism normally inhabiting a CO2-rich environment: Hymenolepis diminuta (Cestoda) in the rat intestine

1978 ◽  
Vol 56 (11) ◽  
pp. 2344-2354 ◽  
Author(s):  
R. B. Podesta
Keyword(s):  
Metabolic Pathways ◽  
Intestinal Parasite ◽  
Hymenolepis Diminuta ◽  
Ambient Fluid ◽  
Rat Intestine ◽  
Ion Concentrations ◽  
Intracellular Ion Concentrations ◽  
Metabolic Reactions ◽  
Stimulation Of

H+ and Na+ transport by the intestinal parasite Hymenolepis diminuta were studied in vitro. The flatworms acidified the ambient fluid by secreting H+ and the acidification could not be correlated with organic acid excretion. Ambient CO2-independent H+ secretion was attributed to protons of metabolic origin: dephosphorylation reactions and ionization of organic acids within the tissues. Ambient CO2-dependent H+ secretion was attributed to protons produced as a result of the hydration of CO2 within the tissue and to the stimulation of anaerobic metabolic pathways by CO2 acting as a cosubstrate in energy metabolism. Studies in which Na+ uptake was stimulated by CO2 or glucose and inhibited by ouabain, amiloride, or Na+ replacement suggested a partial direct coupling of Na+ absorption and H+ secretion but the different activation energies and the effect of buffer anions other than HCO3− suggested an indirect interaction. Various interactions were considered, including the effect of CO2 and intracellular ion concentrations on metabolic reactions leading to the supply of protons for H+ secretion and energy for ion transport.

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