Rapid changes in the surface of parasitic nematodes during transition from pre- to post-parasitic forms

Parasitology ◽  
1993 ◽  
Vol 107 (1) ◽  
pp. 107-117 ◽  
Author(s):  
L. Proudfoot ◽  
J. R. Kusel ◽  
H. V. Smith ◽  
W. Harnett ◽  
M. J. Worms ◽  
...  
Keyword(s):  
Trichinella Spiralis ◽  
Lateral Diffusion ◽  
Nematode Species ◽  
Oral Route ◽  
Culture Conditions ◽  
Parasitic Nematodes ◽  
Surface Coat ◽  
Nippostrongylus Brasiliensis ◽  
Dauer Larva

SummaryAll mammalian-parasitic stages of a range of nematode species investigated (Brugia pahangi, Acanthocheilonema viteae, Strongyloides ratti, Nippostrongylus brasiliensis, Trichinella spiralisandOstertagia ostertagi) labelled in a surface-restricted manner with the fluorescent lipid analogues 5-N-(octadecanoyl)aminofluorescein (AF18) or nitrobenzoxadiazole-cholesterol (NBD-chol), but failed to bind other similar probes. In contrast, the surfaces of the ‘pre-parasitic’ infective stages of these species had affinity for neither AF18 nor NBD-chol. This exclusion of lipid analogues changed rapidly upon exposure of the larvae to tissue culture conditions which mimic the mammalian tissue environment (e.g. RPMI 1640/37°C) such that the above probes could then insert into the surface layer of the larvae. The dauer larva ofCaenorhabditis elegansalso excluded the probes, but became permissive to labelling upon stimulation to emerge from the dauer state. The time taken for the surface transformation to occur ranged from less than 10 min in the vector-borne parasites to approximately 5 h in those which enter by the oral route, with direct skin-penetrators occupying an intermediate position. In all cases, the alteration proceeded too rapidly for it to have been associated with a moult. Fluorescence Recovery After Photobleaching (FRAP) studies ofA. viteaelarvae showed that approximately 50% of the AF18 probe was free to diffuse within the plane of the surface immediately after transformation. This is only a transitory state because AF18 was found to be highly restricted in its lateral diffusion on the surface of adult parasites. In the larvae ofS. ratti, the change in affinity for AF18 was accompanied by the rapid shedding of an otherwise stable surface coat of polyanionic material, here visualized by labelling with fluorescein-conjugated cationized ferritin. Incubation of larvae in lipid-rich host serum during the induction of transformation inhibited subsequent labelling with AF 18. This possibly reflects competition for insertion sites and anin vivopropensity towards the acquisition of host lipid by invading parasites.

Effects of four tanniferous plant extracts on thein vitroexsheathment of third-stage larvae of parasitic nematodes

Parasitology ◽  
2006 ◽  
Vol 132 (4) ◽  
pp. 545-554 ◽  
Author(s):  
D. BAHUAUD ◽  
C. MARTINEZ-ORTIZ DE MONTELLANO ◽  
S. CHAUVEAU ◽  
F. PREVOT ◽  
F. TORRES-ACOSTA ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Extracts ◽  
Castanea Sativa ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Rye Grass ◽  
Pine Tree ◽  
Third Stage

The anthelmintic properties of tanniferous plants and of their secondary metabolites represent one possible alternative to chemotherapy that is currently being explored as a means of achieving sustainable control of gastrointestinal nematodes in ruminants. Previousin vivoandin vitroresults suggest that tanniferous plants can have direct anti-parasitic effect against different stages of nematodes. However, the mode of action of the bioactive plant compounds remains obscure. The objectives of the current study were (1) to examine the hypothesis that extracts of tanniferous plants might interfere with the exsheathment of third-stage infective larvae (L3); (2) to assess the role of tannins in the process by examining the consequence of adding an inhibitor of tannins (polyethylene glycol: PEG) to extracts. The effects of 4 tanniferous plant extracts on exsheathment have been examined on L3 ofHaemonchus contortusandTrichostrongylus colubriformis. Artificial exsheathment was inducedin vitroby adding hypochloride solution to larval suspension. The evolution of exsheathment with time was measured by repeated observations at 10-min interval for 60 min. The selected plants were: genista (Sarothamnus scoparius), heather (Erica erigena), pine tree (Pinus sylvestris), and chestnut tree (Castanea sativa), with tannin contents ranging from 1·5 to 24·7% of DM. Extracts of a non-tanniferous plant (rye grass, tannin content: 0·3% of DM) were included in the assay as negative controls. The extracts were tested at the concentration of 600 μg/ml and the effects were compared to the rate of exsheathment of control larvae in PBS. No statistical differences in the pattern of exsheathment was observed after addition of rye grass or genista extracts for both nematode species and with heather extracts forT. colubriformis. In contrast, pine tree extracts on larvae of both species and heather extracts withH. contortusinduced a significant delay in exsheathment. Last, contact with chest nut extracts led to a total inhibition of the process for both nematodes. These results suggest that extracts of tanniferous plants might affect a key process in the very early stages of larval invasion of the host. In most cases, the addition of PEG led to a total or partial restoration towards control values. This suggests that tannins are largely involved in the inhibitory process. However, other secondary metabolites may also interfere with the process that would help to explain some of the differences in response observed between the two nematode species.

Effect of dietary condensed tannins on gastrointestinal nematodes

2001 ◽  
Vol 137 (4) ◽  
pp. 461-469 ◽  
Author(s):  
N. L. BUTTER ◽  
J. M. DAWSON ◽  
D. WAKELIN ◽  
P. J. BUTTERY
Keyword(s):  
Condensed Tannins ◽  
Trichinella Spiralis ◽  
Condensed Tannin ◽  
Intestinal Lumen ◽  
Parasitic Nematodes ◽  
Nippostrongylus Brasiliensis ◽  
Small Intestinal Mucosa ◽  
Quebracho Tannin ◽  
Small Intestinal

It has been previously shown in this laboratory that feeding a model condensed tannin, quebracho tannin, reduces the small intestinal nematode burden in sheep and rats. The aim of the current programme was to determine whether this occurs through direct toxicity against the parasites. Both in vivo and in vitro studies were conducted. The first study compared the effect of dietary quebracho tannin (40 g/kg) on the establishment of the parasitic nematodes Nippostrongylus brasiliensis and Trichinella spiralis in the rat small intestine. The burden of N. brasiliensis, which, although closely associated with the mucosa, actually dwells within the small intestinal lumen, was significantly reduced (P<0·001) by dietary quebracho tannin. In contrast, T. spiralis, which penetrates into the small intestinal mucosa, was unaffected (>0·05) by the dietary inclusion of quebracho tannin. The second study involved monitoring the survival of adult N. brasiliensis and T. spiralis when incubated in vitro in varying concentrations of quebracho tannin in Hanks’ balanced salt solution. The survival of N. brasiliensis was compromised at concentrations as low as 0·01% (w/v) quebracho tannin but improved with the addition of 0·1% (w/v) polyethylene glycol, which binds to, and inactivates, tannin. T. spiralis was similarly affected, but much more rapidly. These results suggest that dietary quebracho tannin may reduce nematode worm burdens through a toxic effect that requires direct contact between parasite and tannin. This raises the possibility that feeding locally available plant material containing condensed tannins may be an alternative method for controlling parasite infections, especially in areas such as the tropics and subtropics.

Host immune status affects maturation time in two nematode species – but not as predicted by a simple life-history model

Parasitology ◽  
2003 ◽  
Vol 127 (5) ◽  
pp. 507-512 ◽  
Author(s):  
M. A. GUINNEE ◽  
A. W. GEMMILL ◽  
B. H. K. CHAN ◽  
M. E. VINEY ◽  
A. F. READ
Keyword(s):  
Immune Responses ◽  
Nematode Species ◽  
Parasitic Nematodes ◽  
Nippostrongylus Brasiliensis ◽  
Short Term ◽  
Maturation Time ◽  
Nematode Parasites ◽  
Nude Rats ◽  
Immune Mediated ◽  
Fitness Benefits

In theory, the age at which maturation occurs in parasitic nematodes is inversely related to pre-maturational mortality rate, and cross-species data on mammalian nematodes are consistent with this prediction. Immunity is a major source of parasite mortality and parasites stand to gain sizeable fitness benefits through short-term adjustments of maturation time in response to variation in immune-mediated mortality. The effects of thymus-dependent immune responses on maturation in the nematode parasites Strongyloides ratti and Nippostrongylus brasiliensis were investigated using congenitally thymus-deficient (nude) rats. As compared with worms in normal rats, reproductive maturity of parasites (presence of eggs in utero) in nude rats occurred later in S. ratti but earlier in N. brasiliensis. Immune-mediated differences in maturation time were not associated with differences in worm length. Thymus-dependent immunity had no effect on pre-maturational mortality. Results are discussed in relation to theoretical expectations and possible explanations for the observed patterns in parasite maturation.

Identification and characterization of excreted–secreted products and surface coat antigens of animal and plant-parasitic nematodes

Parasitology ◽  
1999 ◽  
Vol 118 (4) ◽  
pp. 397-405 ◽  
Author(s):  
M. E. LOPEZ DE MENDOZA ◽  
R. H. C. CURTIS ◽  
S. GOWEN
Keyword(s):  
Meloidogyne Incognita ◽  
Trichinella Spiralis ◽  
Parasitic Nematodes ◽  
Surface Coat ◽  
Plant Parasitic Nematodes ◽  
Carbohydrate Epitopes ◽  
Host Parasite ◽  
Identification And Characterization ◽  
Plant Parasitic

Nematode surface coat (SC) proteins and excreted–secreted products (E–S) are likely to play important roles in the host–parasite interaction and considerable similarities can be found in SC proteins and E–S products from certain plant and animal parasitic nematodes. Monoclonal antibodies raised to E–S products of plant-parasitic nematodes were shown to cross-react with E–S products and the surface coats of the animal parasites Trichinella spiralis and Haemonchus contortus. Most of the antibodies recognized carbohydrate epitopes but the activity of 2 MAbs (IACR–CCNj.2a.15 and IACR-Misec.8D.3) which recognized proteic epitopes in these nematodes were further characterized. Antibody 2a.15 recognized the SC and oral exudate of Meloidogyne incognita, T. spiralis and H. contortus. This antigen was also immunolocalized in the lining of the oesophagus and gut and in the exudate present during ecdysis of H. contortus L3. Antibody 8D.3 reacted with the SC of these nematodes on cryosections but on live nematodes the immunofluorescence was very patchy and was shed from the nematode SC.

scholarly journals Muc5ac: a critical component mediating the rejection of enteric nematodes

2011 ◽  
Vol 208 (5) ◽  
pp. 893-900 ◽  
Author(s):  
Sumaira Z. Hasnain ◽  
Christopher M. Evans ◽  
Michelle Roy ◽  
Amanda L. Gallagher ◽  
Kristen N. Kindrachuk ◽  
...  
Keyword(s):  
De Novo ◽  
Trichinella Spiralis ◽  
Nematode Infection ◽  
Nippostrongylus Brasiliensis ◽  
Chronic Infections ◽  
Trichuris Muris ◽  
Intestinal Nematode ◽  
Ifn Γ ◽  
Deficient Mice

De novo expression of Muc5ac, a mucin not normally expressed in the intestinal tract, is induced in the cecum of mice resistant to Trichuris muris infection. In this study, we investigated the role of Muc5ac, which is detected shortly before worm expulsion and is associated with the production of interleukin-13 (IL-13), in resistance to this nematode. Muc5ac-deficient mice were incapable of expelling T. muris from the intestine and harbored long-term chronic infections, despite developing strong TH2 responses. Muc5ac-deficient mice had elevated levels of IL-13 and, surprisingly, an increase in the TH1 cytokine IFN-γ. Because TH1 inflammation is thought to favor chronic nematode infection, IFN-γ was neutralized in vivo, resulting in an even stronger TH2-type immune response. Nevertheless, despite a more robust TH2 effector response, the Muc5ac-deficient mice remained highly susceptible to chronic T. muris infection. Importantly, human MUC5AC had a direct detrimental effect on nematode vitality. Moreover, the absence of Muc5ac caused a significant delay in the expulsion of two other gut-dwelling nematodes (Trichinella spiralis and Nippostrongylus brasiliensis). Thus, for the first time, we identify a single mucin, Muc5ac, as a direct and critical mediator of resistance during intestinal nematode infection.

Nematocide activity of 6,7-diarylpteridines in three experimental models

1999 ◽  
Vol 73 (4) ◽  
pp. 333-336 ◽  
Author(s):  
C. Ochoa ◽  
M. Rodríguez ◽  
L. Domínguez ◽  
J. Saldaña ◽  
R. Di Maio ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Trichinella Spiralis ◽  
Experimental Models ◽  
Moderate Activity ◽  
Nippostrongylus Brasiliensis ◽  
Heligmosomoides Polygyrus ◽  
Method Of Evaluation ◽  
Pteridine Derivatives

Thein vitronematocide activity of seventeen 6,7-diarylpteridines has been tested using three different experimental models,Caenorhabditis elegans,Nippostrongylus brasiliensisandHeligmosomoides polygyrus. The method of evaluation of inhibition in the secretion of acetylcholinesterase byH. polygyrusseems to be the most indicated to avoid false positives. Thein vivoactivities, againstTrichinella spiralis, of the mostin vitroactive pteridines have been assayed. All pteridine derivatives bearing 6,7-di-p-bromophenyl substituents have shownin vitronematocide activites in the three experimental models used. Amongst all the pteridines testedin vivo, only 2,4-pteridinedithione derivatives exhibited moderate activity.

scholarly journals A tale of three kingdoms: members of the Phylum Nematoda independently acquired the detoxifying enzyme cyanase through horizontal gene transfer from plants and bacteria

Parasitology ◽  
2018 ◽  
Vol 146 (4) ◽  
pp. 445-452 ◽  
Author(s):  
D. S. Zarlenga ◽  
M. Mitreva ◽  
P. Thompson ◽  
R. Tyagi ◽  
W. Tuo ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Trichinella Spiralis ◽  
Phylogenetic Analyses ◽  
Active Role ◽  
Parasitic Nematodes ◽  
Terrestrial Plants ◽  
Free Living ◽  
Western Blots

AbstractHorizontal gene transfer (HGT) has played an important role in the evolution of nematodes. Among candidate genes, cyanase, which is typically found only in plants, bacteria and fungi, is present in more than 35 members of the Phylum Nematoda, but absent from free-living and clade V organisms. Phylogenetic analyses showed that the cyanases of clade I organismsTrichinellaspp.,Trichurisspp. andSoboliphyme baturini(Subclass: Dorylaimia) represent a well-supported monophyletic clade with plant cyanases. In contrast, all cyanases found within the Subclass Chromadoria which encompasses filarioids, ascaridoids and strongyloids are homologous to those of bacteria. Western blots exhibited typical multimeric forms of the native molecule in protein extracts ofTrichinella spiralismuscle larvae, where immunohistochemical staining localized the protein to the worm hypodermis and underlying muscle. RecombinantTrichinellacyanase was bioactive where gene transcription profiles support functional activityin vivo. Results suggest that: (1) independent HGT in parasitic nematodes originated from different Kingdoms; (2) cyanase acquired an active role in the biology of extantTrichinella; (3) acquisition occurred more than 400 million years ago (MYA), prior to the divergence of the Trichinellida and Dioctophymatida, and (4) early, free-living ancestors of the genusTrichinellahad an association with terrestrial plants.

Ultrastructural Study of a differentiating human colon carcinoma cell line

1990 ◽  
Vol 48 (3) ◽  
pp. 208-209
Author(s):  
Sylvie Polak-Charcon ◽  
Mehrdad Hekmati ◽  
Yehuda Ben Shaul
Keyword(s):  
Cell Line ◽  
Morphological Changes ◽  
Secretory Granules ◽  
Human Colon ◽  
Cell Types ◽  
Culture Conditions ◽  
Morphological Evidence ◽  
Human Colon Carcinoma Cell ◽  
Colon Cell

The epithelium of normal human colon mucosa “in vivo” exhibits a gradual pattern of differentiation as undifferentiated stem cells from the base of the crypt of “lieberkuhn” rapidly divide, differentiate and migrate toward the free surface. The major differentiated cell type of the intestine observed are: absorptive cells displaying brush border, goblet cells containing mucous granules, Paneth and endocrine cells containing dense secretory granules. These different cell types are also found in the intestine of the 13-14 week old embryo.We present here morphological evidence showing that HT29, an adenocarcinoma of the human colon cell line, can differentiate into various cell types by changing the growth and culture conditions and mimic morphological changes found during development of the intestine in the human embryo.HT29 cells grown in tissue-culture dishes in DMEM and 10% FCS form at late confluence a multilayer of morphologically undifferentiated cell culture covered with irregular microvilli, and devoid of tight junctions (Figs 1-3).

Effect of brefeldin A (BFA) on the unique surface coat of pulmonary intravascular macrophages (PIMs) of sheep: Ultrastructural and cytochemical study

1993 ◽  
Vol 51 ◽  
pp. 18-19
Author(s):  
Baljit Singh
Keyword(s):  
Brefeldin A ◽  
Ultrastructural Feature ◽  
Surface Coat ◽  
Anterograde Transport ◽  
Cytochemical Study ◽  
Active Involvement ◽  
Electron Lucent ◽  
Pulmonary Intravascular Macrophages ◽  
Unique Surface

The PIM of sheep, calf, goat and horse has a characteristic ultrastructural feature in the form of a unique, heparin sensitive, globular surface coat present around the plasma membrane with an intervening electron lucent space of 32-40 nm. We previously showed the active involvement of this surface coat in the phagocytosis of tracer material like monastral blue and cationized ferritin. The surface coat is capable of reconstitution in vivo following disruption with heparin. The present study was aimed to investigate whether PIM is the source of surface coat or not. In the recent years the BFA has been extensively used to understand the secretory pathways in the cells because of its ability to cause a rapid and reversible block to the anterograde transport of proteins from the endoplasmic reticulum to the Golgi.Sheep (n=6) were weighed, their plasma volume was calculated indirectly and based on which a sufficient single intravenous dose of BFA was given so as to reach a concentration of 4-5 microgram/ml of plasma.

scholarly journals Investigating the Feasibility of Mefenamic Acid Nanosuspension for Pediatric Delivery: Preparation, Characterization, and Role of Excipients

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 574
Author(s):  
Nikhat Perween ◽  
Sultan Alshehri ◽  
T. S. Easwari ◽  
Vivek Verma ◽  
Md. Faiyazuddin ◽  
...  
Keyword(s):  
Particle Size ◽  
Mefenamic Acid ◽  
Hydroxypropyl Methylcellulose ◽  
Sodium Dodecyl ◽  
Aqueous Solubility ◽  
Oral Route ◽  
Precipitation Method ◽  
Antisolvent Precipitation

Molecules with poor aqueous solubility are difficult to formulate using conventional approaches and are associated with many formulation delivery issues. To overcome these obstacles, nanosuspension technology can be one of the promising approaches. Hence, in this study, the feasibility of mefenamic acid (MA) oral nanosuspension was investigated for pediatric delivery by studying the role of excipients and optimizing the techniques. Nanosuspensions of MA were prepared by adopting an antisolvent precipitation method, followed by ultrasonication with varying concentrations of polymers, surfactants, and microfluidics. The prepared nanosuspensions were evaluated for particle size, morphology, and rheological measures. Hydroxypropyl methylcellulose (HPMC) with varying concentrations and different stabilizers including Tween® 80 and sodium dodecyl sulfate (SLS) were used to restrain the particle size growth of the developed nanosuspension. The optimized nanosuspension formula was stable for more than 3 weeks and showed a reduced particle size of 510 nm with a polydispersity index of 0.329. It was observed that the type and ratio of polymer stabilizers were responsive on the particle contour and dimension and stability. We have developed a biologically compatible oral nanoformulation for a first-in-class drug beautifully designed for pediatric delivery that will be progressed toward further in vivo enabling studies. Finally, the nanosuspension could be considered a promising carrier for pediatric delivery of MA through the oral route with enhanced biological impact.

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