| characterization of a hemoglobin-like protein from adult haemonchus contortus. | a hemoglobin-like protein was purified from supernatants of adult haemonchus contortus extracts by high-pressure liquid chromatography. the purified protein had an m(r) of 33 kda as determined by size-exclusion chromatography under non-denaturing conditions and an m(r) of 19 kda by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the hemoglobin may exist as a dimer. the sequences of 3 peptides resulting from proteolytic digest of the purified protein were determined and demo ... | 1999 | 10219312 |
| influence of ruminal bypass on the pharmacokinetics and efficacy of benzimidazole anthelmintics in sheep. | oxfendazole, fenbendazole and albendazole were each administered at 5mgkg(-1) to sheep fitted with abomasal cannulae as a single bolus intra-ruminally or infused intra-abomasally at a declining exponential rate, with half-life equivalent to the rate of rumen fluid outflow. the pharmacokinetic disposition of parent compound and metabolites in plasma and abomasal fluid was determined by high performance liquid chromatography. compared with intra-ruminal administration, intra-abomasal infusion of f ... | 1999 | 10221631 |
| further studies on anthelmintic resistance in sheep at an organised farm in arid region of rajasthan. | faecal egg count reduction test (fecrt) and in vitro egg hatch assay (eha) was performed on indian karakul (3/4 crosses of karakul with malpura, marwari and sonadi) transported from arid region campus, bikaner, where resistance was reported in 1996. fecrt revealed that fenbendazole and levamisole were 100% effective in reducing the egg counts. lc50 value on eha was 0.074 +/- 0.015 microg thiabendazole ml(-1). the faecal culture examination revealed the presence of haemonchus contortus only. it w ... | 1999 | 10223352 |
| further immunization and biochemical studies with a protective antigen complex from the microvillar membrane of the intestine of haemonchus contortus. | immunization of sheep with a protective antigen complex from the intestinal cells of haemonchus contortus in freund's adjuvant stimulated individually variable antibody responses but still conferred significant protection against parasite infection. correlation between antibody concentration and degree of protection was suggestive of antibody being the effector mechanism. the antigen is known as haemonchus galactose-containing glycoprotein complex (h-gal-gp) because it binds to lectins with a sp ... | 1999 | 10320616 |
| immunization with an affinity purified protein extract from the adult parasite protects lambs against infection with haemonchus contortus. | young lambs were immunized with membrane protein extracts from adult haemonchus contortus which had been enriched for cysteine protease activity using thiol-sepharose chromatography. the resulting extract comprised several peptides including cysteine as well as serine and metallo-protease activities although the former predominated. a limited number of the peptide components were glycosylated. following a single challenge infection with the same parasite, vaccinated lambs had substantially reduc ... | 1999 | 10320617 |
| the distribution of pepsinogen within the abomasa of cattle and sheep infected with ostertagia spp. and sheep infected with haemonchus contortus. | the effect of nematode infections on the production of pepsinogen by ruminants was investigated immunohistochemically and biochemically. abomasal tissues were collected from parasite-naive cattle and sheep, from sheep infected with predominantly ostertagia circumcincta, sheep infected experimentally with haemonchus contortus and cattle infected with ostertagia ostertagi. pepsinogen was also assayed biochemically in homogenates of fundic mucosae from sheep infected with predominantly o. circumcin ... | 1999 | 10321586 |
| the development of vaccines against gastrointestinal nematode parasites, particularly haemonchus contortus. | many parasitic nematodes are developing resistance to chemical treatment, and the search is on to produce commercially viable molecular vaccines. much progress has been made with highly protective 'hidden antigens', especially for haemonchus contortus, and recent work with new 'natural antigens' has yielded promising results. here, sue newton and ed munn review the most recent advances in these two main approaches to this problem. | 1999 | 10322325 |
| haemonchus contortus: characterization of a glutamate binding site in unselected and ivermectin-selected larvae and adults. | a specific ivermectin-sensitive, glutamate binding site has been identified in the parasitic nematode haemonchus contortus. glutamate binding in h. contortus was saturable and occurred in a single class of high-affinity binding sites which appeared to have pharmacological properties different from those of mammalian glutamate receptors. adult and larval forms of h. contortus had dramatically different glutamate binding kinetics, the larvae showing nearly up to 200-fold higher bmax values and up ... | 1999 | 10329363 |
| peroxide-supported in-vitro cytochrome p450 activities in haemonchus contortus. | the potential for cytochrome p450 from haemonchus contortus to operate in the oxygen-poor intestinal environment was investigated by examining the ability of the cytochrome to act in vitro as a peroxygenase in utilising cumene hydroperoxide for substrate oxidations not requiring molecular oxygen. peroxygenase and nadph-supported monooxygenase activities were measured in microsomes prepared from l3 and adult nematodes. both cumene hydroperoxide- and nadph-supported ethoxycoumarin o-deethylase and ... | 1999 | 10333321 |
| the intramammary inflammatory response of genetically resistant merino ewes infected with haemonchus contortus. | the mammary glands of 103 pasture-reared non-lactating, non-pregnant merino ewes were infused via the teat canal with antigens prepared from the nematode haemonchus contortus, and the inflammatory response to infusion assessed by washing the gland of its contents after 24 h and 14 days. the ewes were of two genotypes: one with proven high levels of resistance to infection with the nematode h. contortus, the other random-bred animals with relative susceptibility to infection. on day 0 of a h. con ... | 1999 | 10333329 |
| long-term effects of short-term provision of protein-enriched diets on resistance to nematode infection, and live-weight gain and wool growth in sheep. | weaner sheep that had been hand-fed on diets containing increasing concentrations of protein for a 9-week period (when uninfected, or infected with haemonchus contortus) were studied during the next 69 weeks when put on to pasture as a single, unsupplemented flock. during the 9-week period, groups of 12 sheep (six infected, six uninfected) were offered one of five iso-energetic (9.0 mj kg(-1)) diets containing 10, 13, 16, 19 or 22% crude protein. all sheep were treated with anthelmintic at the e ... | 1999 | 10333332 |
| identification and characterization of excreted-secreted products and surface coat antigens of animal and plant-parasitic nematodes. | 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 ... | 1999 | 10340331 |
| efficacy of topically administered doramectin against eyeworms, lungworms, and gastrointestinal nematodes of cattle. | to evaluate efficacy of topically administered doramectin against eyeworms, lungworms, and gastrointestinal nematodes of cattle. | 1999 | 10376888 |
| anthelmintic resistance in sheep and goat farms on peninsular malaysia. | the faecal egg count reduction test (fecrt) was conducted on 39 sheep farms and 9 goat farms located in peninsular malaysia. the anthelmintic groups used in these tests were the benzimidazoles, levamisole, the benzimidazole/levamisole combination, macrocyclic lactones and closantel. results indicated that the prevalence of resistance to the benzimidazole group was high, with approximately 50% of the sheep farms and 75% of the goat farms having resistant nematode parasite populations present. res ... | 1999 | 10384906 |
| differences in the second internal transcribed spacer (its-2) of eight species of gastrointestinal nematodes of ruminants. | genetic differences in the nucleotide sequence of the second internal transcribed spacers (its-2) among trichostrongylus axei, trichostrongylus colubriformis, ostertagia ostertagi, cooperia oncophora, cooperia punctata, nematodirus helvetianus, nematodirus filicollis, and haemonchus contortus are described. the its-2 sequences of the 8 species ranged between 230 and 241 base pairs in length. sequence similarities between the different genera varied between 60% and 80%. identities between the dif ... | 1999 | 10386433 |
| structural characterisation and pharmacology of kheylrfamide (af2) and ksaymrfamide (pf3/af8) from haemonchus contortus. | the fmrfamide-related peptides (farps), kheylrfamide (af2) and ksaymrfamide (pf3) were structurally characterised from the parasitic nematode of sheep, haemonchus contortus (mh isolate). both peptides were sequenced in a single gas-phase sequencing run and their structure confirmed by mass spectrometry which identified peptides of 920 da (c-terminally amidated af2) and 902/918 da (c-terminally amidated non-oxidised/oxidised pf3, respectively). af2 had inhibitory effects on h. contortus muscle an ... | 1999 | 10391380 |
| the effects of urea supplementation on production and parasitological responses of sheep infected with haemonchus contortus and trichostrongylus colubriformis. | merino wether lambs were individually confined and fed a basal diet of oaten chaff containing essential minerals which was untreated or contained 3% urea. within each dietary group animals were orally infected with either 200 h. contortus (h), 1000 t. colubriformis (t) or both species (h + t) thrice weekly or remained uninfected (c). weight gain, wool production, and parasite burden were measured over a 19-week period. sheep on the diet containing urea gained more weight, consumed more feed and ... | 1999 | 10392968 |
| duration of activity of oral moxidectin against haemonchus contortus, teladorsagia circumcincta and trichostrongylus colubriformis in goats. | | 1999 | 10399250 |
| haemonchus contortus: effects of glutamate, ivermectin, and moxidectin on inulin uptake activity in unselected and ivermectin-selected adults. | using [(3)h]inulin uptake as a measure of pharyngeal pumping activity, we have investigated and compared the effects of glutamate, ivermectin, and moxidectin on inulin uptake in susceptible and ivermectin-selected haemonchus contortus. inulin uptake is inhibited by glutamate, ivermectin, and moxidectin, at biologically relevant concentrations. glutamate influences the responses to both ivermectin and moxidectin, suggesting that these three substances share a common mechanism of action. the effec ... | 1999 | 10403760 |
| the organization of a galectin gene from teladorsagia circumcincta. | galectins are a family of soluble beta-galactoside-binding lectins that are conserved amongst a broad range of organisms. we have previously isolated cdna clones coding for galectins from the sheep gastrointestinal nematode parasites teladorsagia circumcincta, haemonchus contortus and trichostrongylus colubriformis, revealing a high level of identity between these molecules. this subsequent study reports the organization of the t. circumcincta tci-gal-1 galectin gene. the coding region is broken ... | 1999 | 10413054 |
| variation in resistance to haemonchosis: selection of female sheep resistant to haemonchus contortus. | seventy female lambs (6-7 months old) which were exposed to natural infections of haemonchus contortus were designated as responders or non-responders on the basis of 10 weekly cumulative faecal egg counts. selected responder and non-responder lambs were treated with ivermectin, housed separately and 6 weeks post-housing, seven lambs from each group were given a trickle infection of haemonchus contortus at 1000 l3 daily for 5 days per week up to 2 weeks and examined weekly for 10 weeks after fir ... | 1999 | 10431374 |
| unexpected increased thiabendazole tolerance in haemonchus contortus resistant to anthelmintics by modulation of glutathione activity. | the effect of several modulators of the synthesis or activity of glutathione (gsh) on the susceptibility of haemonchus contortus eggs susceptible or resistant to anthelmintics was investigated using in vitro egg-hatch assays. diethylmaleate, d,l-buthionine-[s,r]-sulfoximine, and patulin induced an unexpected decrease in the susceptibility of resistant eggs to thiabendazole, which was chosen as a reference for resistance to benzimidazole compounds. the results demonstrate that the level of gsh or ... | 1999 | 10431738 |
| predatory behaviour of trapping fungi against srf mutants of caenorhabditis elegans and different plant and animal parasitic nematodes. | the initial infection process of nematode-trapping fungi is based on an interaction between the trapping structure of the fungus and the surface of the nematode cuticle. a bioassay was designed to investigate the predatory response of several isolates of nematode-trapping fungi against 3 mutants of caenorhabditis elegans (at6, at10 and cl261), which have been reported to differ in the reaction of their cuticle to antibodies and lectins. the bioassay was also applied to infective larvae of animal ... | 1999 | 10446708 |
| chemo- and thermosensory neurons: structure and function in animal parasitic nematodes. | nematode parasites of warm-blooded hosts use chemical and thermal signals in host-finding and in the subsequent resumption of development. the free-living nematode caenorhabditis elegans is a useful model for investigating the chemo- and thermosensory neurons of such parasites, because the functions of its amphidial neurons are well known from laser microbeam ablation studies. the neurons found in the amphidial channel detect aqueous chemoattractants and repellants; the wing cells-flattened amph ... | 1999 | 10456420 |
| characterisation of a polymorphic tc1-like transposable element of the parasitic nematode haemonchus contortus. | hctc1, a member of the tc1-family of transposable elements was isolated from the parasitic nematode haemonchus contortus. hctc1 is 1590 bp long, is flanked by 55 bp inverted repeats and carries a single open reading frame of a 340 amino acid transposase-like protein. hctc1 is similar to tc1 of caenorhabditis elegans and elements tcb1 and tcb2 of caenorhabditis briggsae in the inverted terminal repeats, the open reading frame, as well as the target insertion sequence. furthermore, the copy number ... | 1999 | 10477184 |
| cross-reactive antigens of haemonchus contortus adult worms in teladorsagia circumcincta infected goats. | the adult haemonchus contortus somatic antigens responsible for cross-reactivity have been analysed using serum samples from goat kids infected and reinfected with teladorsagia circumcincta. goat kids infected with t. circumcincta had similar serum elisa values against somatic antigens of h. contortus as goats infected with h. contortus itself. immunoblotting confirmed this extensive cross-reactivity particularly in the molecular weight range 105-29 kda. however, peptides with high (195, 152 and ... | 1999 | 10478421 |
| decreased ivermectin and moxidectin sensitivity in haemonchus contortus selected with moxidectin over 14 generations. | ivermectin resistance in the nematode haemonchus contortus has been reported in many parts of the world and many ivermectin resistant isolates have been found to have reduced sensitivity to moxidectin. however, it is unclear whether parasites that are selected with moxidectin would demonstrate reduced sensitivity to ivermectin. in this study, the effects of moxidectin and ivermectin on an unselected strain and a strain of h. contortus derived from the unselected strain but selected over 14 gener ... | 1999 | 10489206 |
| analysis of helminth genetic data: comparative examples with haemonchus contortus isozymes using exact tests or resampling procedures. | population genetic data on helminths are scarce and it is important to fine tune analyses of these data, the interpretation of which is based on between-(fst) and within-(fis) population variability. several computer programs are available and confidence intervals of each index are based on different procedures. these programs (genetix, diploid, genepop) were compared with a classical program (biosys-1) using a large set of haemonchus contortus isozyme data. the results were identical for all so ... | 1999 | 10494814 |
| identification and stage-specific expression of two putative p-glycoprotein coding genes in onchocerca volvulus. | the potential for the development of ivermectin (ivm) resistance in microfilariae of onchocerca volvulus and the existence of ivm tolerance in adult worms of this human pathogen are major concerns for the effective control of onchocerciasis. p-glycoprotein (p-gp), an atp-binding transporter protein associated with multidrug resistance in mammals, protozoa and the nematode, haemonchus contortus, might play important roles in the development of ivm resistance and/or in the tolerance of adult o. vo ... | 1999 | 10498183 |
| defined characteristics of cathepsin b-like proteins from nematodes: inferred functional diversity and phylogenetic relationships. | numerous cathepsin b-like protein sequences (cbls) have been reported from nematodes. however, the relationships among these proteins remain unclear. here, expression of several cbl transcripts in the gut of the parasitic nematode haemonchus contortus was demonstrated. to assess potential functional diversity, multiple nematode cbl sequences were compared with known functional domains of cathepsin b. these domains included the occluding loop, s2' and s2 subsites, and the pro region. four groups ... | 1999 | 10498185 |
| investigation of intestinal nematode responses to naphthalophos and pyrantel using a larval development assay. | responses of several nematode species to naphthalophos and pyrantel/levamisole were examined using a larval development assay in order to determine the potential of this assay for detection of resistance. haemonchus contortus and ostertagia circumcincta showed concentration-dependent responses to naphthalophos, however, the assay was unsuitable for trichostrongylus colubriformis due to the low toxicity of the drug to the larval stages of this nematode. measurement of concentration-dependent resp ... | 1999 | 10501619 |
| selection for anthelmintic resistance by macrocyclic lactones in haemonchus contortus. | two morphologically marked strains of haemonchus contortus, cavrs (smooth-macrocyclic lactone resistant) and mcmaster (linguiform-macrocyclic lactone susceptible), were used to investigate the selection for anthelmintic resistance following exposure to ivermectin (ivm), a non-persistent anthelmintic. and a more persistent anthelmintic, oral moxidectin (mox). three types of selection were investigated: (1) selection of resident worms at the time of treatment (head selection); (2) selection of inc ... | 1999 | 10501620 |
| enhanced absorption of pour-on ivermectin formulation in rats by co-administration of the multidrug-resistant-reversing agent verapamil. | the effect of verapamil, a multidrug-resistance (mdr)-reversing agent on the absorption of a pour-on formulation of ivermectin was evaluated in rats. absorption of ivermectin was effectively enhanced (40%) by the presence of verapamil, suggesting that absorption of ivermectin involves mdr-p-glycoprotein and that verapamil should act as a competitive inhibitor for the transport and extrusion of ivermectin by p-glycoprotein. this hypothesis is consistent with other studies describing verapamil as ... | 1999 | 10540953 |
| ligand-gated chloride channel subunits encoded by the haemonchus contortus and ascaris suum orthologues of the caenorhabditis elegans gbr-2 (avr-14) gene. | the alternatively-spliced caenorhabditis elegans gbr-2/avr-14 gene encodes two subunits of the nematode ligand-gated chloride channel family which forms an important molecular target for the avermectin and related anthelminthics. we used reverse transcriptase-polymerase chain reaction (rt-pcr) techniques to isolate cdnas encoding the products of the gbr-2/avr-14 orthologues from the parasitic nematodes haemonchus contortus and ascaris suum. the predicted polypeptides possess all the characterist ... | 1999 | 10551358 |
| identification of promoter elements of parasite nematode genes in transgenic caenorhabditis elegans. | transformation of the free-living nematode caenorhabditis elegans with promoter/reporter gene constructs is a very powerful technique to examine and dissect gene regulatory mechanisms. no such transformation system is available for parasitic nematode species. we have exploited c. elegans as a heterologous transformation system to examine activity and specificity of parasitic nematode gene promoters. using three different parasite promoter/lac z reporter constructs strict tissue-specific expressi ... | 1999 | 10551361 |
| molecular cloning and characterization of gut-derived cysteine proteinases associated with a host protective extract from haemonchus contortus. | cysteine proteinases have been implicated in the protection conferred by vaccination with detergent-soluble extracts of haemonchus contortus. in the present study, antisera from sheep refractory to haemonchus challenge following vaccination with a 'proteinase-enriched' haemonchus gut membrane extract, were employed to screen a cdna expression library of the adult parasite. this resulted in the isolation of 3 cdnas (designated hmcp1, 4 and 6) encoding cathepsin b-like cysteine proteinases. immuno ... | 1999 | 10581619 |
| cloning and characterization of a beta-galactoside-binding protein (galectin) from the gut of the gastrointestinal nematode parasite haemonchus contortus. | a cdna encoding a beta-galactoside-binding lectin (galectin) was identified by immunoscreening a haemonchus contortus cdna library with antisera from lambs vaccinated with a membrane protein complex (h-gal-gp) derived from the parasites' gut. the cdna sequence, exhibiting a tandem repeat structure and designated hco-gal-2, showed significant levels of similarity with galectins from several species of nematode as well as mammalian galectin type 4. native galectin was preferentially extracted from ... | 1999 | 10599080 |
| effects of the multidrug-resistance-reversing agents verapamil and cl 347,099 on the efficacy of ivermectin or moxidectin against unselected and drug-selected strains of haemonchus contortus in jirds (meriones unguiculatus). | the development of anthelmintic resistance is making parasite control in small ruminants problematic. following the discovery that the drug transporter p-glycoprotein may be involved in macrocyclic lactone resistance in haemonchus contortus, we determined the effect of two multidrug-resistance modulators, verapamil and cl347,099, on the efficacy of ivermectin and moxidectin against unselected and drug-selected strains of h. contortus. cl347,099 is an analog of verapamil that has multidrug-resist ... | 1999 | 10599924 |
| core alpha1-->3-fucose is a common modification of n-glycans in parasitic helminths and constitutes an important epitope for ige from haemonchus contortus infected sheep. | synthesis of parasite specific ige plays a critical role in the defence against helminth infections. we report here that ige from serum from schistosoma mansoni infected mice and haemonchus contortus infected sheep recognizes complex-type n-glycans from arabidopsis thaliana, which contain r-glcnacbeta1-->4(fucalpha1-->3)glcnacbeta1-asn (core alpha1-->3-fuc) and xylbeta1-->2manbeta1-->4glcnacbeta1-r (core beta1-->2-xyl) modifications, and honeybee phospholipase a2, which carries n-glycans that co ... | 1999 | 10601665 |
| protection in lambs vaccinated with haemonchus contortus antigens is age related, and correlates with ige rather than igg1 antibody. | protection by vaccination with excretory-secretory products (es) from haemonchus contortus, containing predominantly proteins of 15 and 24 kda, against an experimental challenge infection depends on the age of the sheep. vaccinated sheep 9, 6 or 3 months of age were protected for 83%, 77% and -34%, respectively. there was a significant difference in es-specific serum ige response but not in igg1 response, after the last vaccination between the different age groups. in the protected 9-month-old a ... | 2000 | 10607286 |
| multiple lethal effects induced by a benzimidazole anthelmintic in the anterior intestine of the nematode haemonchus contortus. | a mechanism of benzimidazole efficacy against parasitic nematodes is postulated to involve inhibition of intestinal secretory vesicle transport via depolymerization of microtubules. we show that fenbendazole (fbz) treatment of lambs causes pathology localized to the anterior intestine in the parasitic nematode haemonchus contortus. the pathology included gross disintegration of the anterior intestine, dna fragmentation in anterior intestinal nuclei with characteristics of an apoptosis-like proce ... | 2000 | 10613701 |
| transposon associated markers for the parasitic nematode haemonchus contortus. | we have previously characterized a tcl-like transposable element hctcl, from the parasitic nematode haemonchus contortus. here we describe the genetic variation of hctcl insertion sites in h. contortus populations differing in geographical origin, resistance to chemotherapeutics and level of inbreeding. clear differences between populations were observed on southern blots with a hctcl-specific probe. sequencing the 5'- or 3'-flanks of individual hctcl integration sites allowed the design of pcr ... | 2000 | 10613705 |
| multiple anthelmintic resistance in a goat herd. | anthelmintic resistance was monitored over a 30 month period within a goat herd in eastern virginia, usa. resistance to ivermectin, levamisole and benzimidazole drugs was detected in haemonchus contortus using the fecal egg count reduction test (fecrt). when levamisole use was discontinued for 1 year, susceptibility to levamisole appeared to return. although a single treatment with fenbendazole was able to reduce fecal egg counts by only 50%, two doses administered in a 12 h interval increased e ... | 2000 | 10622608 |
| description of haemonchus placei (place, 1893) (nematoda, trichostrongylidae, haemonchinae), identification and intra-specific morphologic variability. | haemonchus placei in cattle has never been completely described, possibly due to great morphological similarity with small ruminants haemonchus contortus. it is newly described on one isolate from argentina. it has clear distinct morphological features from sheep and goats haemonchus contortus and presents only two female morphotypes (linguiform and knobbed) instead of three recorded in h. contortus. a key is proposed to identify females. female as well as male haemonchus placei from new world ( ... | 1999 | 10633504 |
| relative protective properties of three membrane glycoprotein fractions from haemonchus contortus. | jacalin lectin was used as a ligand to isolate a fraction containing two distinct protective antigens from detergent extracts of membranes from haemonchus contortus. the first antigen was identified as a complex which appeared very similar to haemonchus galactose-containing glycoprotein (h-gal-gp), which is a previously described protective protease complex, except that it was substantially depleted of one of the main h-gal-gp components, a 230 kda metallopeptidase-containing band. the new compl ... | 2000 | 10652118 |
| vaccination of manchego lambs against haemonchus contortus with a somatic fraction (p26/23) of adult parasites. | a low molecular weight fraction from adult haemonchus contortus containing two peptides (p26/23) was used to vaccinate manchego female lambs between 3.5 and 5 months of age. immunizing injections were given three times on days 0, 14 and 28 of the experiment. on day 43, lambs were challenged with 400 third stage larvae/kg live weight. vaccination induced a lengthening of prepatent periods, significant reduction (> 60%) in mean faecal egg counts and smaller variations in packed cell volume values. ... | 2000 | 10672194 |
| inheritance of avermectin resistance in haemonchus contortus. | a larval development assay was used to compare the responses of the chiswick avermectin resistant (cavrs) isolate of haemonchus contortus, an avermectin-susceptible isolate (vrsg) and their crosses to avermectins. the f(1) and f(2) generations of reciprocal crosses between cavrs and vrsg were denoted as cavrs malesxvrsg females=cxv, and vrsg malesxcavrs females=vxc. the levels of avermectin resistance in the developing larvae of the f(1) of both cxv and vxc were indistinguishable from that in th ... | 2000 | 10675751 |
| the effect of oxfendazole terminated infections with haemonchus contortus on the development of immunity in sheep. | the relative contribution of third (l3), fourth (l4) or adult stages of haemonchus contortus to the development of immunity was evaluated in three groups of sheep subjected to infections terminated by oxfendazole treatments at the l3, l4 or adult stage. a control group did not receive immunising infections. all the groups were challenged with 5000 l3, to evaluate the protection provided by the different protocols. all sheep were necropsied at the end of the experiment to count the abomasal worm ... | 2000 | 10681023 |
| the efficacy of levamisole, and a mixture of oxfendazole and levamisole, against the arrested stages of benzimidazole-resistant haemonchus contortus and ostertagia circumcincta in sheep. | sheep were allowed to graze pasture that had been seeded with benzimidazole-resistant haemonchus contortus and ostertagia circumcincta in order to acquire a burden of arrested larvae. following housing, sheep were dosed orally with either oxfendazole at a dose rate of 4.7 mg/kg (to confirm the benzimidazole-resistant status of the species of nematode), levamisole at a dose rate of 7.5 mg/kg, or an oxfendazole/levamisole mixture at a dose rate of 4.6 mg/kg oxfendazole and 8.1 mg/kg levamisole. th ... | 2000 | 10681032 |
| variability of resistance in goats infected with haemonchus contortus in brazil. | the variability between and within breeds with respect to nematode egg counts (epg), packed cell volume (pcv) and hemoglobin (hb) was studied in 36 yearling female goats of the caninde (15), bhuj (6) and anglo-nubian (15) breeds, exposed to haemonchus contortus. nematode-free goats were turned to a contaminated paddock in late february. from then on, fecal egg per gram counts (epg), packed cell volume (pcv) and hemoglobin (hb) were determined at 2-week intervals up to week 18. the epg, transform ... | 2000 | 10681034 |
| sensory neuroanatomy of a passively ingested nematode parasite, haemonchus contortus: amphidial neurons of the first stage larva. | when infective larvae of haemonchus contortus (a highly pathogenic, economically important, gastric parasite of ruminants) are ingested by grazing hosts, they are exposed to environmental changes in the rumen, which stimulate resumption of development. presumably, resumption is controlled by sensory neurons in sensilla known as amphids. neuronal function can be determined by ablation of specifically recognized neurons in hatchling larvae (l1) in which neuronal cell bodies are easily visualized u ... | 2000 | 10683605 |
| a comparison of the infectivity of cryopreserved versus unfrozen infective larvae of haemonchus contortus, trichostrongylus colubriformis and trichostrongylus axei. results of the onderstepoort veterinary institute and collaborators from 1977 to the present. | the infectivity for sheep of cryopreserved infective larvae (l3) of various strains of haemonchus contortus, trichostrongylus colubriformis and trichostrongylus axei is compared using previously published results of trials conducted at the onderstepoort veterinary institute laboratories, and of collaborators. the means and ranges of development were similar for both frozen and unfrozen larvae of two of the three worm species reviewed. a mean of 33.4% (range, 12.7-63.0%) of cryopreserved h. conto ... | 1999 | 10689701 |
| characterization of acid phosphatase and phosphorylcholine hydrolase in adult haemonchus contortus. | an acid phosphatase (ap) and a phosphorylcholine hydrolase (pch) were detected in excretory-secretory (esp) products from adult haemonchus contortus. the ap had a ph optimum of 4.5 and was inhibited by tartaric acid and sodium fluoride, but not by o-phenanthroline. the ap hydrolyzed paranitrophenol (pnp)-phosphate and to a lesser extent pnp-phenyl-phosphonate but did not hydrolyze diester substrates. purified ap consisted of heterodimers with relative molecular weight (mr) of 41.9 and 48.7 kda a ... | 2000 | 10701555 |
| induction of t helper 1- and t helper 2-type immune responses during haemonchus contortus infection in sheep. | the production of cytokines by lymphoid cells, isolated from non-infected and haemonchus contortus-infected lambs, was investigated. particular attention was paid to differences in t helper 1- (th1) and th2-type immune profiles between genetically resistant and random-bred animal groups. non-infected resistant and random-bred lambs produced equivalent levels of interferon-gamma (ifn-gamma) and interleukin-5 (il-5), from isolated abomasal lymph node cells (aln), mesenteric lymph node cells (mln) ... | 2000 | 10712677 |
| parenterally administered gastrointestinal nematode infective larvae viable after more than 15 years in liquid nitrogen. | after cryopreservation for 13.3-15.8 years, the viability of the infective larvae (l3) of trichostrongylus axei, t. colubriformis, oesophagostomum columbianum, haemonchus contortus, ostertagia circumcincta, t. falculatus, nematodirus spathiger, chabertia ovina and dictyocaulus filaria was assessed in sheep, by being deposited at their predilection sites. d. filaria was, however, an exception, in that the l3 were injected into the jugular vein. the mean development of all the species was 22.8%, b ... | 2000 | 10714461 |
| a family of galectins from haemonchus contortus. | | 2000 | 10717307 |
| changes in the lipophilicity of the surfaces of meloidogyne incognita and haemonchus contortus during exposure to host signals. | the surfaces of plant and animal parasitic nematodes share certain lipids, which seem to be important in the infection process. the surfaces of 2 parasitic nematodes, meloidogyne incognita and haemonchus contortus, were activated by different ph buffers to allow the insertion of different fluorescent probes. the lipid analogue pkh26 and the surface charge indicator, cationized ferritin, were used as probes with these nematodes but labelled only the retaining 2nd-stage moulted cuticle of h. conto ... | 2000 | 10726281 |
| in vivo activities of the new anthelmintic depsipeptide pf 1022a. | pf 1022a is a member of a new class of cyclic depsipeptides with antiparasitic activity. following in vitro and laboratory animal studies it was tested for its anthelmintic efficacy in companion and livestock animals against a wide spectrum of intestinal nematodes and lungworms. studies were carried out in rats, dogs, horses, sheep, and cattle. animals were either naturally or experimentally infested. the efficacy of pf 1022a was investigated against the following parasite species: strongyloides ... | 2000 | 10726989 |
| non-autonomous transposable elements in the genome of the parasitic nematode haemonchus contortus. | | 2000 | 10743620 |
| from isolates to a synthetic laboratory population: maintenance of variability in the nematode haemonchus contortus. | haemonchus contortus isolates were collected from goats of five locations with different climatic characteristics in guadeloupe archipelago. they were investigated for morphology, morphometrics and allozyme diversity after passage in immunosuppressed lambs using long acting corticoids. the basic aim of the work was to construct a synthetic strain in laboratory conditions which was representative of the isolates. the isolates were only slightly different although climatic conditions were very dif ... | 2000 | 10743645 |
| evaluation of immunization with gut membrane glycoproteins of ostertagia ostertagi against homologous challenge in calves and against haemonchus contortus in sheep. | peanut and cona lectins were used as ligands to isolate glycoproteins from detergent extracts of adult ostertagia ostertagi membranes. as judged by their profiles following sds-page, these fractions closely resembled the equivalents from haemonchus contortus which are derived from the nematode intestinal cell microvillar membranes and which are highly protective when used as antigens. groups of calves were immunized with the peanut and cona binding fractions of ostertagia, either as separate or ... | 2000 | 10792763 |
| nematode parasites of adult dairy cattle in the netherlands. | abomasa, blood samples and faecal samples for examination of nematode infections were collected from 125 dairy cows during the period november 1997-october 1998. of these, 12 had no grazing history and were, therefore, excluded from this study. from the remaining 113, 88.5% had nematode eggs in the faeces. larval identification of the positive cultures showed that ostertagia spp. larvae were most frequent (97%), followed by trichostrongylus spp. (29%), oesophagostomum spp. (23%), cooperia puncta ... | 2000 | 10799842 |
| l-glutamate binding sites of parasitic nematodes: an association with ivermectin resistance? | nematode membrane preparations contain high amounts of low-affinity specific l-glutamate binding sites. the numbers of these sites were increased in 2 isolates, one field-derived and the other laboratory-derived, of ivermectin-resistant haemonchus contortus and a field isolate of ivermectin-resistant telodorsagia circumcincta, when compared to control, drug-sensitive isolates. specific [3h]ivermectin binding to these membrane preparations showed no differences between ivermectin-sensitive and re ... | 2000 | 10840983 |
| host specificity of abomasal nematodes in free ranging alpine ruminants. | abomasums from 641 alpine wild ruminants representing five different species (cervus elaphus, capreolus capreolus, rupicapra rupicapra, capra ibex, ovis musimon) and from 19 domestic sheep (ovis aries) from alpine areas were examined in order to investigate the host-specificity of abomasal helminths. nine out of 20 helminth species were found in at least five different host species. a discriminant analysis was able to significantly discriminate the hosts on the basis of their helminth community ... | 2000 | 10842002 |
| isolation and characterization of a novel inducible mammalian galectin. | a novel mammalian galectin cdna (ovgal11) was isolated by representational difference analysis from sheep stomach (abomasal) tissue infected with the nematode parasite, haemonchus contortus. the mrna is greatly up-regulated in helminth larval infected gastrointestinal tissue subject to inflammation and eosinophil infiltration. immunohistological analysis indicates that the protein is localized in the cytoplasm and nucleus of upper epithelial cells of the gastrointestinal tract. the protein is al ... | 2000 | 10851241 |
| the binding of closantel to ovine serum albumin, and homogenate fractions of haemonchus contortus. | closantel binds to the serum proteins of the host and affects blood sucking parasites when they ingest the blood of treated hosts. closantel binds specifically to ovine serum albumin (k(a) of 9. 3x10(6)m(-1)) at site i, the warfarin/phenylbutazone binding site of albumin closantel also binds to invertebrate haemocyanin and haemolymph. the strongest binding of closantel in homogenates of h. contortus is found in fractions containing soluble proteins. this binding is of low affinity and, because t ... | 2000 | 10856512 |
| haemonchus contortus (nematoda: trichostrongylidae) is much more sensitive than caenorhabditis elegans (nematoda: rhabditidae) to the ovicidal action of thiabendazole. | when eggs of the trichostrongylid nematode haemonchus contortus were exposed to thiabendazole, the concentration required to prevent hatching in 90% of the eggs (mic90) was found to be 0.1 microg/ml (using 1% dimethylsulfoxide [dmso] as solvent). in contrast, eggs of the free-living rhabditid nematode caenorhabditis elegans hatched at normal rates at a concentration 200 times higher, i.e., 20 microg/ml, and showed only a partial inhibitory effect at a concentration 1,200 times higher, i.e., 120 ... | 2000 | 10864269 |
| immunological responses of sheep to haemonchus contortus. | infections with haemonchus contortus are a major constraint on ruminant health world-wide. young lambs are very sensitive to haemonchus infection. older lambs and sheep acquire immunity after a continuous or seasonal exposure to the parasite. the mechanisms underlying immunity are still not completely understood. antibodies, in particular local iga and ige, certainly play a role. the role of igg is less clear. lymphocyte proliferation responses seem to correlate to immunity. sheep that have high ... | 2000 | 10874710 |
| protection of merino lambs against haemonchus contortus by trickle infection of neonates. | in two trials, lambs were trickle infected with 400 or 1000 infective larvae of haemonchus contortus (hcl(3)), twice weekly for 4 weeks from the day of birth. following anthelminthic treatment at 6 weeks (trial 1) or 7 weeks of age (trial 2), lambs were challenged 1 week later with a trickle infection totalling 5000 (trial 1) or 10000 hcl(3) (trial 2). in both cases, significant protection (p<0.05) ranging from 42 to 79% was achieved against egg and worm counts. serum antibody responses as well ... | 2000 | 10882906 |
| thermotaxis and thermosensory neurons in infective larvae of haemonchus contortus, a passively ingested nematode parasite. | as a basis for studies of thermal behavior of infective larvae (l3) of haemonchus contortus resulting from ablation of amphidial neurons, the locations of the amphidial cell bodies in the hatchling larva (l1) were compared with their locations in the l3. we sought to verify that killing each targeted cell body in l1 destroys the putative corresponding dendrite of the l3. these comparisons confirmed the predicted cell body-to-dendrite connections, as well as similarities in the general amphidial ... | 2000 | 10888739 |
| cellular profiles in the abomasal mucosa and lymph node during primary infection with haemonchus contortus in sheep. | cellular changes in the abomasal tissue and draining abomasal lymph nodes were examined after primary infection of lambs with haemonchus contortus for 3, 5 or 27-36 days. infection with h. contortus larvae resulted in a rapid and selective increase in the percentage of cd4(+) t-cells in the abomasal lymph node at 3 days post-infection (pi). by 5 days pi, the lymph node weight had increased two-fold; however, the percentage of lymphocyte populations in the abomasal lymph node resembled that seen ... | 2000 | 10889303 |
| serodiagnosis of haemonchosis with a somatic antigen (hc26) in several breeds of sheep. | sera from 53 sheep belonging to castellano, churro, manchego, and merino breeds were analyzed to test the diagnostic value of a 26-kd antigen from adult haemonchus contortus at prepatency and early and late patency of experimental haemonchosis. animals that received zero, 1, or 2 infections with the parasite were tested. in addition, sera from 20 experimentally infected and 10 noninfected texel sheep were used to test the antigen. sera from 37 infected animals at prepatency as well as at patency ... | 2000 | 10907865 |
| attempts to control haemonchosis in grazing ewes by vaccination with gut membrane proteins of the parasite. | a vaccination trial was conducted to evaluate the potential benefit of haemonchus contortus gut membrane proteins as vaccine antigens under field conditions in louisiana. the trial was conducted in the summer of 1996 in a flock of ewes grazing pasture naturally infected with h. contortus. ewes were randomly assigned to three treatment groups (vaccine, adjuvant only, and saline) and fecal egg counts (fec, measured as eggs per gram of feces), packed cell volumes (pcv), and antibody levels were mon ... | 2000 | 10936542 |
| oxidase activities in macrocyclic-resistant and -susceptible haemonchus contortus. | the role of oxidative metabolism in resistance to macrocyclic lactones in haemonchus contortus was examined by measuring activities toward 2 model cytochrome p450 substrates, aldrin and ethoxycoumarin, in a susceptible and a resistant isolate of the parasite. microsomal preparations from larvae and adults of the 2 isolates showed no differences in levels of nadph- or cumene hydroperoxide-supported aldrin epoxidase or ethoxycoumarin o-deethylase activities. intact adult nematodes showed an abilit ... | 2000 | 10958478 |
| characterisation of the beta-tubulin gene of cylicocyclus nassatus? | mrna and genomic dna were isolated from adult cylicocyclus nassatus, and the mrna was reverse transcribed. the cdna was pcr amplified using degenerate primers designed according to the alignment of the beta-tubulin amino acid sequences of other species. to complete the coding sequence, the 3' end was amplified with the 3' race, and for amplification of the 5' end the sl1-primer was used. the cdna of the beta-tubulin gene of c. nassatus spans 1429 bp and encodes a protein of 448 amino acids. spec ... | 1999 | 10961850 |
| a hybridisation technique to identify anthelmintic resistance genes in haemonchus. | the identification of genes associated with anthelmintic resistance can be facilitated in haemonchus contortus by the ability of this species to hybridise with haemonchus placei. although the hybrid males are sterile, the lines can be rescued by backcrossing the females to either parental species. resistance genes can be retained in haemonchus hybrids, while the unwanted contortus background is removed through backcrossing to h. placei and anthelmintic selection of the progeny. under this select ... | 1999 | 10961854 |
| genetic markers for the parasitic nematode haemonchus contortus based on intron sequences. | | 2000 | 10964652 |
| est sequencing of the parasitic nematode haemonchus contortus suggests a shift in gene expression during transition to the parasitic stages. | expressed sequence tags from the parasitic nematode haemonchus contortus were generated in order to identify anchor loci for comparative mapping between nematode genomes and candidate targets for future control measures. in total, 370 sl1 trans-spliced cdnas from different developmental stages representing 195 different genes were partially sequenced. from these expressed sequence tags 50% were similar to genes with a known or predicted function and 19% were similar to nematode sequences with no ... | 2000 | 10989145 |
| microsatellite diversity of isolates of the parasitic nematode haemonchus contortus. | the alarming development of anthelmintic resistance in important gastrointestinal nematode parasites of man and live-stock is caused by selection for specific genotypes. in order to provide genetic tools to study the nematode populations and the consequences of anthelmintic treatment, we isolated and sequenced 59 microsatellites of the sheep and goat parasite haemonchus contortus. these microsatellites consist typically of 2-10 tandems ca/gt repeats that are interrupted by sequences of 1-10 bp. ... | 2000 | 10989146 |
| the neurons of class ald mediate thermotaxis in the parasitic nematode, strongyloides stercoralis. | strongyloides stercoralis, a skin-penetrating nematode parasite of homeotherms, migrates to warmth. in nematodes, the amphids, anteriorly positioned, paired sensilla, each contain a bundle of sensory neurons. in the amphids of the free-living nematode caenorhabditis elegans, a pair of neurons, each of which ends in a cluster of microvilli-like projections, are known to be the primary thermoreceptors, and have been named the finger cells (class afd). a similar neuron pair in the amphids of the pa ... | 2000 | 10996330 |
| interaction between trypanosoma evansi and haemonchus contortus infection in goats. | an experimental study on interaction between trypanosoma evansi and haemonchus contortus infections was conducted in 42 male barbari goats of 6-9 months age. parasitological observations like prepatent period, faecal egg count, worm burden and mortality were made in animals infected with h. contortus followed 1 week later with t. evansi and vice versa. these parameters were also examined in animals with single infection with each of these parasites. it was revealed that t. evansi infection in go ... | 2000 | 10996737 |
| examination of gastrointestinal helminth in livestock grazing in grassland of bangladesh. | to determine association of grassland with parasitic diseases of livestock in bangladesh, the 'tracer' animals (two cow calves and two goats) were released for a month in a grassland used for communal grazing of livestock near school premise in kanthal, trishal, mymensingh, bangladesh. after slaughtering of the tracer animals, their gastrointestinal tract examination revealed six species of nematode and one cestode. the nematode species were haemonchus contortus, trichostrongylus axei, mecistoci ... | 2000 | 11002657 |
| immunisation of lambs with drug-abbreviated haemonchus contortus infections: protection against homologous and heterologous challenge. | haemonchus contortus is known as a prolific parasite, producing high numbers of eggs. it could therefore be used as a cheap source of larvae for immunisation of lambs. the value of immunisation would be improved if the immunity produced gave protection against not only homologous but also heterologous infections. because antibody cross-reactivity between haemonchus and ostertagia has been well established, we wanted to know whether drug-abbreviated infections of h. contortus would stimulate prod ... | 2000 | 11002985 |
| efficacy of copper oxide needles for the control of nematode parasites in dairy goats. | the spread of benzimidazole-resistant nematodes in dairy goat farms is of a great concern as probably more than 70% of the flocks are involved. as there are very few other anthelmintic options during the lactating period, we have evaluated the efficacy of copper oxide needles (con, copinox, bayer, uk) in both experimental and natural infections in goats. the curative effect of con (2-4 g) on existing worm burdens was assessed in goats experimentally infected with teladorsagia circumcincta, haemo ... | 2000 | 11014608 |
| the fmrfamide-like neuropeptide af2 is present in the parasitic nematode haemonchus contortus. | peptides belonging to the fmrfamide family are widely distributed amongst invertebrates. we report here on the isolation of the fmrfamide neuropeptide af2 (lys-his-glu-tyr-leu-arg-phe-nh2) from the parasitic nematode haemonchus contortus. immunocytochemical techniques showed that fmrfamide-like material was distributed in several regions of these organisms including nerve cords and cell bodies of the central nervous system. af2 was isolated using a method that employed 6 steps of reverse-phase h ... | 1995 | 11023415 |
| oral infectivity of cryopreserved haemonchus contortus infective larvae that recovered relatively slowly when thawed after more than 15 years in liquid nitrogen. | infective larvae (l3) of two different batches of anthelmintic-susceptible haemonchus contortus, cryopreserved for 15,6 and 15,7 years in liquid nitrogen appeared dead when examined 10-20 min after thawing. however, having become motile later in the day, their viability was tested the next day in two separate groups of sheep. the mean development of 41,8% and 66,3% of the h. contortus compared favourably with previous trials with this strain, in which the l3 were injected into the abomasa of she ... | 2000 | 11028752 |
| cathepsin b-like cysteine proteases confer intestinal cysteine protease activity in haemonchus contortus. | cathepsin b-like cysteine protease genes (cbls) constitute large multigene families in parasitic and nonparasitic nematodes. although expressed in the intestine of some nematodes, the biological and biochemical functions of the cbl proteins remain unresolved. di- and tetra-oligopeptides were used as fluorogenic substrates and irreversible/competitive inhibitors to establish cbl functions in the intestine of the parasitic nematode haemonchus contortus. cysteine protease activity was detected agai ... | 2001 | 11032834 |
| a molecular tool for species identification and benzimidazole resistance diagnosis in larval communities of small ruminant parasites. | this report describes a molecular method for determining in a first step the generic composition of a nematode community and in a second step, the resistance of each species to benzimidazole (bz). we first established a polymerase chain reaction (pcr) linked to a restriction fragment length polymorphism strategy using the isotype 1 beta-tubulin gene. this method overcame the limitations of morphological identification of larval stages of trichostrongylid nematode species. geographically distant ... | 2000 | 11038310 |
| uptake of albendazole and albendazole sulphoxide by haemonchus contortus and fasciola hepatica in sheep. | the pattern of in vivo uptake of albendazole (abz) and its major metabolite, abz-sulphoxide (abzso), by haemonchus contortus and fasciola hepatica recovered from abz-treated sheep, was investigated. concentration profiles of both compounds were simultaneously measured in target tissues/fluids from the same infected sheep. in addition, the proportion of the (+) and (-) abzso enantiomers was determined in plasma, bile and f. hepatica recovered from treated sheep. sheep naturally infected with h. c ... | 2000 | 11078946 |
| nematode parasites of sheep: a survey of epidemiological parameters and their application in a simple model. | we review the literature on parameter values relevant to the epidemiology of strongyle nematode infections of domestic sheep. information is subdivided by parasite genus, country of origin and climate type. while field observations have been made in a large number of countries, the bulk of studies under controlled conditions have been conducted in australia, new zealand and the uk. for these countries, experiments and parameters are interpreted in terms of a previously published model of nematod ... | 2000 | 11085228 |
| evaluation of a laboratory test to detect resistance to closantel in haemonchus contortus. | to evaluate a laboratory test for closantel resistance in haemonchus contortus. | 2000 | 11098388 |
| an anthelmintic compound, nafuredin, shows selective inhibition of complex i in helminth mitochondria. | infections with parasitic helminths are important causes of morbidity and mortality worldwide. new drugs that are parasite specific and minimally toxic to the host are needed to counter these infections effectively. here we report the finding of a previously unidentified compound, nafuredin, from aspergillus niger. nafuredin inhibits nadh-fumarate reductase (complexes i + ii) activity, a unique anaerobic electron transport system in helminth mitochondria, at nm order. it competes for the quinone ... | 2001 | 11120889 |
| a developmentally regulated hyaluronidase of haemonchus contortus. | the trichostrongylid nematode haemonchus contortus released a hyaluronic acid-degrading enzyme during in vitro development from the third (l3) to fourth (l4) larval stage. the enzyme did not degrade chondroitin sulfate a. enzyme activity was optimal between ph 4.0 and 6.0, and the enzyme was inhibited by high concentrations of nacl; the divalent cations cu2+, zn2+, ca2+, and mn2+ were not inhibitory. the hyaluronidase had a molecular mass estimated at 57 kda by sucrose density gradient centrifug ... | 2000 | 11128510 |
| individual expression of recombinant alpha- and beta-tubulin from haemonchus contortus: polymerization and drug effects. | three tubulin isotypes from the parasitic nematode haemonchus contortus were individually expressed in escherichia coli, purified, and induced to polymerize into microtubules in the absence of microtubule-associated proteins. the effect of different conditions on the rate of polymerization of pure tubulin was assessed. this is the first time that recombinant alpha-tubulin has been shown to be capable of polymerization into microtubule-like structures when incubated with recombinant beta-tubulin. ... | 2001 | 11162384 |
| expression of haemonchus contortus pepsinogen in caenorhabditis elegans. | a genomic copy of a gut-expressed haemonchus contortus candidate vaccine antigen, pepsinogen, was isolated using the polymerase chain reaction (pcr). the isolated sequence was 4 kb in length and contained eight introns ranging in size from 54 to 1475 base pairs. this sequence, together with its 3' non-coding dna region containing a polyadenylation signal sequence, was cloned into the bluescript sk(+) vector immediately downstream of the caenorhabditis elegans cpr-5 gene promoter. this promoter h ... | 2001 | 11166393 |
| epidemiology of parasitic gastrointestinal nematode infections of ruminants on smallholder farms in central kenya. | in order to establish the infection pattern with gastrointestinal nematodes in ruminants in the central kenya highlands, a study was carried out in 58 smallholder farms. the study involved monthly faecal examinations from sheep, goats and cattle and pasture sampling from eight communal grazing areas. each month, six dorper worm-free tracer lambs were introduced and four locally grazed cross-bred sheep were purchased for parasite recovery. the mean faecal egg counts (fec) for cattle were low thro ... | 2001 | 11170849 |
| a single-chain variable region immunoglobulin library from the abomasal lymph node of sheep infected with the gastrointestinal nematode parasite haemonchus contortus. | sheep immunoglobulin (ig) heavy-chain (v(h)dj(h)) and lambda light-chain variable region (v(lambda)j(lambda)) nucleotide coding sequence was isolated by reverse transcriptase-polymerase chain reaction (rt-pcr) from abomasal lymph node (aln) b cells of immune sheep challenged with the gastrointestinal nematode parasite haemonchus contortus. single-chain antibodies (scfv) were then constructed with the purified v(h)dj(h) and v(lambda)j(lambda) ig gene region dna using oligonucleotides to pcr and j ... | 2001 | 11182152 |
| a preliminary study on the anthelmintic activity of calotropis procera latex against haemonchus contortus infection in najdi sheep. | the anthelmintic activity of calotropis procera latex was investigated in sheep that had been infected with single oral doses of 12000 infective haemonchus contortus larvae. inappetence, dullness, erosive abomasitis, decreased haemoglobin concentration and increased eosinophils were the main features of haemonchosis in the sheep. in the sheep treated with single oral doses of 0.01 ml or 0.02 ml/kg body weight of c. procera latex, egg production was significantly reduced, but not completely suppr ... | 2001 | 11214673 |
| sensory neuroanatomy of a passively ingested nematode parasite, haemonchus contortus: amphidial neurons of the third-stage larva. | the sensory neuronal ultrastructure of the amphids of the infective larva (l3) of haemonchus contortus was analyzed, compared, and contrasted with that of the first-stage larva (l1). as in l1, each amphid of the l3 is innervated by 12 neurons. thirteen ciliated dendritic processes of 10 neurons, 3 with double processes, lie in each amphidial channel. the dendritic process of each finger cell neuron ends in a large number of digitiform projections or "fingers," many more than in the l1. processes ... | 2001 | 11227904 |
| ancylostoma caninum: the finger cell neurons mediate thermotactic behavior by infective larvae of the dog hookworm. | bhopale, v. m., kupprion, e. k., ashton, f. t., boston, r., and schad, g. a. 2001. ancylostoma caninum: the finger cell neurons mediate thermotactic behavior by infective larvae of the dog hookworm. experimental parasitology 97, 70-76. in the amphids (anteriorly positioned, paired sensilla) of the free-living nematode caenorhabditis elegans, the so-called finger cells (afd), a pair of neurons, each of which ends in a cluster of microvilli-like projections, are known to be the primary thermorecep ... | 2001 | 11281703 |