Anthelmintic activity of chicory (Cichorium intybus): in vitro effects on swine nematodes and relationship to sesquiterpene lactone composition

Chicory is a perennial crop that has been investigated as a forage source for outdoor-reared ruminants and pigs, and has been reported to have anthelmintic properties. Here, we investigated in vitro anthelmintic effects of forage chicory-extracts against the highly prevalent swine parasites Ascaris suum and Oesophagostomum dentatum. Methanol extracts were prepared and purified from two different cultivars of chicory (Spadona and Puna II). Marked differences were observed between the anthelmintic activity of extracts from the two cultivars. Spadona extracts had potent activity against A. suum third (L3) and fourth (L4) - stage larvae, as well as O. dentatum L4 and adults, whereas Puna II extracts had less activity against A. suum and no activity towards O. dentatum L4. Transmission-electron microscopy of A. suum L4 exposed to Spadona extracts revealed only subtle changes, perhaps indicative of a specific anthelmintic effect rather than generalized toxicity. Ultra-high liquid chromatography-mass spectrometry analysis revealed that the purified extracts were rich in sesquiterpene lactones (SL), and that the SL profile differed significantly between cultivars. This is the first report of anthelmintic activity of forage chicory towards swine nematodes. Our results indicate a significant anthelmintic effect, which may possibly be related to SL composition.

Anthelmintic activity of trans-cinnamaldehyde and A- and B-type proanthocyanidins derived from cinnamon (Cinnamomum verum)

Cinnamon (Cinnamomum verum) has been shown to have anti-inflammatory and antimicrobial properties, but effects on parasitic worms of the intestine have not been investigated. Here, extracts of cinnamon bark were shown to have potent in vitro anthelmintic properties against the swine nematode Ascaris suum. Analysis of the extract revealed high concentrations of proanthocyanidins (PAC) and trans-cinnamaldehyde (CA). The PAC were subjected to thiolysis and HPLC-MS analysis which demonstrated that they were exclusively procyanidins, had a mean degree of polymerization of 5.2 and 21% of their inter-flavan-3-ol links were A-type linkages. Purification of the PAC revealed that whilst they had activity against A. suum, most of the potency of the extract derived from CA. Trichuris suis and Oesophagostomum dentatum larvae were similarly susceptible to CA. To test whether CA could reduce A. suum infection in pigs in vivo, CA was administered daily in the diet or as a targeted, encapsulated dose. However, infection was not significantly reduced. It is proposed that the rapid absorption or metabolism of CA in vivo may prevent it from being present in sufficient concentrations in situ to exert efficacy. Therefore, further work should focus on whether formulation of CA can enhance its activity against internal parasites.

What are the infectious larvae in Ascaris suum and Trichuris muris?

In the present study, larvae of Ascaris suum and Trichuris muris were investigated by light and electron microscopy after incubation in a hatching medium containing 89% phosphate-buffered saline (pH 7.4), 10% RPMI-1640 and 1% sodiumhypochlorite at 40 and 37 degrees C, respectively. The larvae were obtained from fertilised eggs of the worms during defined phases of development (A. suum, 36th-50th day of development; T. muris, once a week from week 16 to 20). Light and electron micrographs of the larvae gave evidence that the third larval stage of A. suum is probably the infectious stage. The first moult of the larvae had already taken place before the 36th day of incubation starting at day 1. After 36 days of incubation, only the second larval stage was found within eggs. Some of these larvae were coated by a separated sheath so that a second moult of the larvae is reasonable. On the other hand, no sheathed larvae of T. muris were found in the eggs incubated for 20 weeks in distilled water. No signs of moult were seen for 20 weeks neither on light nor on the electron micrographs. Therefore, in T. muris, the first larval stage is the infectious stage, which was proven by means of re-infections of mice 16, 18 or 20 weeks after incubation of the eggs.

Preparing to move: assembly of the MSP amoeboid motility apparatus during spermiogenesis in Ascaris

We exploited the rapid, inducible conversion of non-motile Ascaris spermatids into crawling spermatozoa to examine the pattern of assembly of the MSP motility apparatus that powers sperm locomotion. In live sperm, the first detectable motile activity is the extension of spikes and, later, blebs from the cell surface. However, examination of cells by EM revealed that the formation of surface protrusions is preceded by assembly of MSP filament tails on the membranous organelles in the peripheral cytoplasm. These organelle-associated filament meshworks assemble within 30 sec after induction of spermiogenesis and persist until the membranous organelles are sequestered into the cell body when the lamellipod extends. The filopodia-like spikes, which are packed with bundles of filaments, extend and retract rapidly but last only a few seconds before giving way to, or converting into, blebs. Coalescence of these blebs, each supported by a dense mesh of filaments, often initiates lamellipod extension, which culminates in the formation of the robust, dynamic MSP fiber complexes that generate sperm motility. The same membrane phosphoprotein that orchestrates assembly of the fiber complexes at the leading edge of the lamellipod of mature sperm is also found at all sites of filament assembly during spermiogenesis. The orderly progression of steps that leads to construction of a functional motility apparatus illustrates the precise spatio-temporal control of MSP filament assembly in the developing cell and highlights the remarkable similarity in organization and plasticity shared by the MSP cytoskeleton and the actin filament arrays in conventional crawling cells.

In vitro studies on the effects of flubendazole against Toxocara canis and Ascaris suum

Adult Toxocara canis and Ascaris suum were incubated in vitro in media containing 0.1, 1, 10 or 100 micro g/ml flubendazole in order to study drug-derived effects. This incubation was done for 8 h and repeated (in some groups) after 24 h for another 8 h. The onset and intensity of flubendazole-derived effects were dosage-dependent and time-dependent, i.e. the same grade of damage was reached when incubating for a longer period at a low dosage or for a shorter period in medium containing a high amount (10 or 100 micro g/ml) of flubendazole. A repeated incubation in drug-containing medium was superior to a single exposure. Flubendazole is apparently able to penetrate into the worm's interior via the cuticle. This became evident in worms with sealed orifices, which showed identical damage to worms which were not sealed. The type of tissue damage due to flubendazole was identical in both worm species when exposed to any of the drug dosages used. The principal mode of action of flubendazole was based on the complete reduction of microtubuli-polymerisation inside the parasite's cells. This apparently led to the complete destruction of the hypodermis, muscle layer and intestine. Flubendazole also stopped the formation of gametes. Summarising, even low concentrations of flubendazole (0.1 micro g/ml) led to significant and irreversible damage in all worms studied.

Immunohistochemical localization and differentiation of phosphocholine-containing antigens of the porcine, parasitic nematode, Ascaris suum

The glycolipids of Ascaris suum represent either neutral, zwitterionic or acidic structures. The acidic fraction comprises a sulphatide and an unusual phosphoinositolglycosphingolipid (Lochnit et al. 1998b). The sulphatide was previously localized to the hypodermis, contractile zone of somatic muscle cells and the external musculature of the female uterus, whereas the presence of the phosphoinositolglycosphingolipid species was restricted to the intestine. The neutral and zwitterionic components belong to the arthro-carbohydrate series, which are substituted in their zwitterionic structures by phosphocholine (PC) and in one glycolipid by an additional phosphoethanolamine residue. In previous immunohistochemical localization studies, however, the chemical nature of the PC-substituted biomolecules has not been investigated in detail. Here, we report on the immunohistochemical localization and differentiation of phosphocholine-containing structures into lipid- and protein-bound species in adult A. suum. The patterns of immunostaining, obtained with a PC-specific monoclonal antibody and anti-zwitterionic glycolipid hyperimmune serum in the female worm, indicated a parallel organ distribution for glycolipid- and protein-bound PC-epitopes. Immunoreactivity was localized to specific tissues of the body wall, intestine and reproductive tract. This is the first report of surface-located PC-epitopes for ascarids. The patterns of immunolabelling obtained with antibodies directed against the unsubstituted arthro-carbohydrate series backbone suggested that the glycolipid-bound epitope was restricted to the hypodermis, whilst the protein-bound antigenic determinant resembled that for PC.

Differentiation of cuticular structures during the growth of the third-stage larva of Ascaris suum (Nematoda, Ascaridoidea) after emerging from the egg

In order to monitor the early phases of the development of Ascaris suum from domestic pigs, third-stage larvae, retrieved from the liver and the lungs, were studied by analyzing worm growth and length increase of individual transverse annuli in the cuticle. Material for study using light and scanning electron microscopy was obtained from experimental infections. The results show that the third-stage larva (not the second-stage) after emergence from the egg grows continuously, without an ecdysis in the liver. During growth, each annulus is split into a complex of 2 subannuli, each of which attains a bimodal appearance and is a prominent feature during a late phase of the third-stage larva. The results suggest that the first 2 molts occur inside the egg, a synapomorphic feature of the Ascaridoidea. The third-stage larvae of ascaridoids, with some functional similarities of the dauer-larva stage of Caenorhabditis sp., facilitate transmission of these parasitic worms to the digestive tract of the vertebrate final host (utilizing the tracheal route in A. suum), where the third and the fourth molts take place.

Centrids, a pair of asymmetrically arranged sense organs in Ascaris suum (Nematoda, Ascaridoidea)

Two prominent, asymmetrically placed cuticular somatic sensilla, called centrids, are reported in Ascaris suum Goeze, 1782, the pig roundworm. The right centrid is situated much more anteriorly on the body than is the left one. The centrids are globular in the fourth-stage larva and obviously void of an apical pore, suggesting at least a tactile function. In adult worms, the centrids are platelike, lacking a globular expansion. The observation on the presence of asymmetrically placed centrids in A. suum gives further impetus to the importance assigned to sense organs in the classification and identification of nematodes. The name centrid was originally chosen to indicate the placement of the papillae in the midbody region of worms. The name centrid, rather than, e.g. postdeirid, is proposed to be used when denoting asymmetrically oriented midbody sensilla among the Ascaridida and papillae, when shown homologous to these, of species within the Rhabditea generally. This proposal is in line with the name "Mittelkörperpapillen" originally adopted to denote homologous sensillae in Cucullanidae (Seuratoidea) by Törnquist in 1931.

Growth and structural features of the adult stage of Ascaris suum (Nematoda, Ascaridoidea) from experimentally infected domestic pigs

For studying the morphogenesis of the adult stage of Ascaris suum, worms were obtained from experimentally infected domestic pigs. Structural and morphometric features of A. suum are analyzed by light and scanning electron microscopy. It was shown that the increase in length of the worm from days 35 to 56 is based on a region-specific lengthening of individual transverse annuli in the cuticle. An increased worm size also results in an increased diameter of different cuticular sense organs. It is shown that a pair of lateral midbody papillae, the centrids, are prominent sensilla in the adult male and female worm. The centrids have an asymmetric placement, the right centrid being more anterior on the worm than the left.

Localization of cytochrome oxidase and the 2-methyl branched-chain enoyl CoA reductase in muscle and hypodermis of Ascaris suum larvae and adults

Rabbit lung-derived third-stage larvae (L3) of Ascaris suum are aerobic and cyanide sensitive but also contain many enzymes specific to anaerobic pathways. To localize these enzymes, diaminobenzidine (DAB) staining for cytochrome oxidase (COX) and immunogold labeling for 2-methylbutyryl enoyl CoA reductase (ECR) were performed on sections of hypodermis and muscle of adults and larvae of A. suum and visualized by transmission electron microscopy. As predicted, adult hypodermal and muscle mitochondria did not exhibit COX staining; however, hypodermal and muscle mitochondria of the L3 and fourth-stage larvae (L4) were DAB positive. In contrast, hypodermal mitochondria from the adult, L3, and L4 did not exhibit ECR immunoreactivity, whereas mitochondria from muscle of all 3 were ECR positive. These observations suggest that both the ECR and COX are colocalized in muscle mitochondria of the L3.

In vitro anthelmintic activity of root-tuber extract of Flemingia vestita, an indigenous plant in Shillong, India

The in vitro activity of root-tuber-peel extract of Flemingia vestita, an indigenous plant consumed by the natives in Northeast India, was tested against helminth parasites. Live parasites (nematode: Ascaris suum from pigs, A. lumbricoides from humans, Ascaridia galli and Heterakis gallinarum from domestic fowl; cestode: Raillietina echinobothrida from domestic fowl; trematode: Paramphistomum sp. from cattle) were collected in 0.9 % physiological buffered saline (PBS) and maintained at 37 +/- 1 degrees C. In vitro treatment of the parasites with the crude extract (50 mg/ml) in PBS revealed complete immobilization of the trematode and cestode in about 43 and 20 min, respectively. However, the cuticle-covered nematodes did not show any change in physical activity and remained viable even after a long period of exposure to the extract. Exposure of R. echinobothrida to genistein (0.5 mg/ml), an active principle isolated from the root-tuber peel, caused spontaneous loss of movement (paralysis) in 4.5 h, which was slower than the time required for praziquantel, the reference flukicide and cestodicide. The treated parasites showed structural alteration in their tegumental architecture. This study suggests the vermifugal activity of this plant extract against trematodes and cestodes.

Ascaris suum: ultrastructural effect of in vitro albendazole therapy

The effect of albendazole therapy on adult Ascaris suum was examined using transmission electron microscopy. The drug induced prominent ultrastructural changes which included the presence of necrotic dense bodies, myelin whorls which appeared to represent various stages of lysosomal formation and autolysis, disruption and erosion of the microvilli. The effects were mainly confined to the central region of the intestinal epithelial cells.

Cellular and subcellular localization of SALMFamide (S1)-like immunoreactivity within the central nervous system of the nematode Ascaris suum (Nematoda, Ascaroidea)

The localization and distribution of SALMFamide (S1)-like immunoreactivity (IR), was determined at both the cellular and subcellular level in the central nervous system (CNS) of the nematode roundworm Ascaris suum. The techniques of indirect immunofluorescence in conjunction with confocal scanning laser microscopy and post-embedding, IgG-conjugated colloidal gold immunostaining were used, respectively. Immunostaining was widespread in the CNS of adult A. suum, with immunoreactivity (IR) being localized in nerve cells and fibres in the ganglia associated with the anterior nerve ring and in the main nerve cords and their commissures. At the subcellular level, gold labeling of peptide was localized exclusively over dense-cored vesicles within nerve cell bodies, nerve axons and nerve terminals of the neuropile of the anterior nerve ring, main ganglia and nerve cords in the CNS. Double-labeling demonstrated an apparent co-localization of S1- and FMRFamide-IR-together with S1- and pancreatic polypeptide (PP)-IR in the same dense-cored vesicles. Antigen preabsorption experiments indicated little cross-reactivity, if any, between the three antisera; indeed, neither FMRFamide nor PP antigens abolished S1 immunostaining.

Ultrastructural localization of pancreatic polypeptide- and FMRFamide immunoreactivities within the central nervous system of the nematode, Ascaris suum (Nematoda: Ascaroidea)

A post-embedding immunogold technique has been used to examine the subcellular distribution of immunoreactivities to vertebrate pancreatic polypeptide (PP) and to the invertebrate peptide, FMRFamide within the central nervous system (CNS) of the nematode, Ascaris suum. Gold labelling of peptide was localized exclusively over dense-cored vesicles within nerve cell bodies, nerve axons and nerve terminals of the main ganglia and nerve cords in the CNS. Double-labelling of peptides demonstrated an apparent co-localization of PP and FMRFamide immunoreactivities in the same dense-cored vesicles, although populations of dense-cored vesicles that labelled solely for FMRFamide were also evident. Antigen preabsorption studies indicated little or no cross-reactivity between the two antisera.

Interaction of mebendazole with tubulin from body wall muscle, intestine, and reproductive system of Ascaris suum

The binding of tritiated mebendazole, a benzimidazole anthelmintic, to tubulin derived from intestine, body wall muscle, and reproductive system of adult Ascaris suum was examined and compared. Mebendazole binding was resolved into specific and nonspecific binding and the binding affinity (Ka) and maximum binding at infinite ligand concentration (Bmax) determined. Electron microscopy was performed to assess the tubulin in various tissues of A. suum quantitatively by observing the presence of microtubules. Total binding was highest in intestine followed by body wall muscle. It was least in the reproductive system. The intestine demonstrated greater specific binding per milligram of protein than the body wall muscle. However, in the reproductive system extract, high affinity binding was not detected. After correction for nonspecific binding of ligand, the results indicated that the Bmax of mebendazole for the tubulin of A. suum intestine was about 3-fold higher than for that of body wall muscle. The Ka of mebendazole for intestinal tubulin was similar to that for body wall muscle. Electron microscopy of A. suum tissues demonstrated that the tubulin content decreased from the intestine through the body wall muscle to the reproductive system. Differences in tubulin content from different tissues may determine the selective sensitivity of these tissues to benzimidazole attack.

Mitochondrial heterogeneity in the parasitic nematode, Ascaris suum

The anaerobic metabolism of Ascaris suum body wall muscle mitochondria has been well characterized, but little is known about the metabolism of other adult tissues. The present study was designed to further characterize the metabolism of mitochondria isolated from A. suum male reproductive tissues, which contain predominately sperm, and to compare it with that of muscle. Cytochrome oxidase activity could not be detected in muscle, testis, or sperm mitochondria either by diaminobenzidine staining or enzymatic assays. However, the activities of several tricarboxylic acid cycle enzymes, including citrate synthase and isocitrate dehydrogenase, were about 100-fold higher in testis/seminal vesicle mitochondria than muscle mitochondria. In contrast, malic enzyme activity in testis/seminal vesicle mitochondria was about 12-fold lower than that in muscle mitochondria. The incorporation of 32Pi into organic phosphate by either muscle or testis/seminal vesicle mitochondria appeared to be dependent on malate and pyruvate, and incorporation was inhibited by rotenone but not cyanide. Thus, the metabolism of testis/seminal vesicle mitochondrial preparations appears to be similar to that of ascarid muscle, despite the elevated levels of tricarboxylic acid cycle enzyme activities present in testis/seminal vesicle mitochondria. The function of these elevated enzymes is unclear, but the possibility that they are used later in the aerobic metabolism of the fertilized egg has not been excluded.