Novel small strongyle (Cyathostominae) beta-tubulin sequences

Samson‐Himmelstjerna, Georg von; Harder, Achim; Pape, M.; Schnieder, Thomas

doi:10.1007/s004360000326

Cited by 35 publications

(14 citation statements)

References 11 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unlike the large strongyle (Strongylinae) group, anthelmintic resistance is common in the Cyathostominae, particularly with regard to benzimidazole compounds such as fenbendazole [54]. Most horses harbour burdens of tens of thousands of these parasites without developing clinical disease, but in some horses, cyathostomin infection leads to a severe inflammatory enteropathy affecting the large intestine [18,32].…”

Section: Background To the Cyathostominaementioning

confidence: 99%

See 1 more Smart Citation

Recent developments in research into the Cyathostominae and Anoplocephala perfoliata

et al. 2004

View full text Add to dashboard Cite

-Intestinal helminths are an important cause of equine disease. Of these parasites, the Cyathostominae are the commonest group that infect horses. These nematodes consist of a complex tribe of 51 species, although individual horses tend to harbour 10 or so common species, in addition to a few rarer species. The Cyathostominae can be extremely pathogenic, and high levels of infection result in clinical symptoms ranging from chronic weight loss to colic, diarrhoea and death. As part of their life cycle, immature cyathostomins penetrate the large intestinal wall, where they can enter a state of inhibited larval development. These larvae can exist in this state for months to years, after which they subsequently re-emerge. If larvae re-emerge in large numbers (i.e. several million), severe pathological consequences ensue. The inhibited larvae are also relatively refractory to several of the currently available anthelmintics, so that horses treated previously with anthelmintics can still carry life-threatening burdens of these parasitic stages. Little is known about the cyathostomin larvae during their mucosal phase, and current research efforts are focused on investigating the biology of these stages. Much of the research described here highlights this area of research and details studies aimed at investigating the host immune responses that the mucosal larvae invoke. As part of this research effort, molecular tools have been developed to facilitate the identification of larval and egg stages of cyathostomins. These molecular tools are now proving very useful in the investigation of the relative contributions that individual, common cyathostomin species make to the pathology and epidemiology of mixed helminth infections. At the more applied level, research is also in progress to develop an immunodiagnostic test that will allow numbers of mucosal larvae to be estimated. This test utilises antigen-specific IgG(T) serum antibody responses as markers of infection. As anthelmintic resistance will be the major constraint on the future control of the Cyathostominae, researchers are now actively investigating this area and studies aimed at elucidating the molecular mechanisms of drug resistance are described. Another parasite which has assumed a clinically important role in horses is the tapeworm, Anoplocephala perfoliata. This parasite is prevalent world-wide and has been shown to be a significant cause of equine colic. Because previous methods of estimating the infection intensity of tapeworm were inaccurate, recent research has been directed at developing an immunodiagnostic ELISA for these cestodes. Specific IgG(T) responses to antigens secreted by adult tapeworms have been shown to provide a reasonable indication of infection intensity. An ELISA based on these responses is now commercially available. The steps involved in the development of this ELISA are described here. In addition to these recent advances in research, this review also outlines the principle areas for future research into these important equin...

show abstract

Section: Background To the Cyathostominaementioning

confidence: 99%

“…The sequence of β-tubulin isotype I gene has been described for seven common cyathostomin species [43,54]. One report suggested that the mutation at codon 200, which is associated with BZ resistance in ruminant nematodes, may not be responsible for BZ resistance in cyathostomins [55].…”

Section: Cyathostomin Anthelmintic Resistancementioning

confidence: 99%

Recent developments in research into the Cyathostominae and Anoplocephala perfoliata

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Variation in b-tubulin amino acid sequences among the currently sequenced genes of different nematode species is low with similarities of around 90% (Bennett et al 1999;Pape et al 1999;Brehm et al 2000;Samson-Himmelstjerna et al 2001). Variations in nucleotide sequences are more marked.…”

Section: Introductionmentioning

confidence: 94%

Analysis of codon usage in ?-tubulin sequences of helminths

Samson‐Himmelstjerna¹,

Harder

Failing

et al. 2003

Parasitology Research

Self Cite

View full text Add to dashboard Cite

Codon usage bias has been shown to be correlated with gene expression levels in many organisms, including the nematode Caenorhabditis elegans. Here, the codon usage (cu) characteristics for a set of currently available beta-tubulin coding sequences of helminths were assessed by calculating several indices, including the effective codon number (Nc), the intrinsic codon deviation index (ICDI), the P2 value and the mutational response index (MRI). The P2 value gives a measure of translational pressure, which has been shown to be correlated to high gene expression levels in some organisms, but it has not yet been analysed in that respect in helminths. For all but two of the C. elegans beta-tubulin coding sequences investigated, the P2 value was the only index that indicated the presence of codon usage bias. Therefore, we propose that in general the helminth beta-tubulin sequences investigated here are not expressed at high levels. Furthermore, we calculated the correlation coefficients for the cu patterns of the helminth beta-tubulin sequences compared with those of highly expressed genes in organisms such as Escherichia coli and C. elegans. It was found that beta-tubulin cu patterns for all sequences of members of the Strongylida were significantly correlated to those for highly expressed C. elegans genes. This approach provides a new measure for comparing the adaptation of cu of a particular coding sequence with that of highly expressed genes in possible expression systems.Finally, using the cu patterns of the sequences studied, a phylogenetic tree was constructed. The topology of this tree was very much in concordance with that of a phylogeny based on small subunit ribosomal DNA sequence alignments.

show abstract

“…Two alleles of the β-tubulin isotype 1 gene from Cylicocyclus nassatus, representing the wild type and the F200Y polymorphism, were isolated and inserted into a cloning vector as previously reported (von Samson-Himmelstjerna et al 2001). The third allele with the F167Y polymorphism was subsequently processed in the same manner.…”

Section: Construction Of Expression Vectorsmentioning

confidence: 99%

“…The genotyping of BZ-resistant populations by allele-specific PCR failed to find a correspondingly high frequency of the TAC polymorphism (von Samson-Himmelstjerna et al 2001). Despite an increase in the frequency of the TAC polymorphism during the development of resistance, another study that monitored TTC/TAC allele frequencies concluded that other mechanisms may be involved in the development of BZ resistance in cyathostomins (Pape et al 2003).…”

mentioning

confidence: 99%

Expression of recombinant β-tubulin alleles from Cylicocyclus nassatus (Cyathostominae)

et al. 2006

View full text Add to dashboard Cite

Small strongyles (Cyathostominae) are common nematode parasites of horses that have developed resistance to the benzimidazole anthelmintics used to control their populations. Evidence suggests that the principal mechanism of resistance involves a phenylalanine-to-tyrosine mutation at codon 200 in the beta-tubulin proteins that are components of microtubules. Other works, however, suggest that a phenylalanine-to-tyrosine mutation at codon 167, or alternative mechanisms, may be involved. As part of an ongoing project examining the role that these two beta-tubulin mutations may play in benzimidazole resistance, we have cloned the wild-type allele and the two alleles with the phenylalanine-to-tyrosine mutations at codons 167 and 200 of the beta-tubulin isotype 1 gene from the small strongyle Cylicocyclus nassatus. In this work, we describe the construction of expression vectors containing these alleles and their expression in Escherichia coli.

show abstract

Novel small strongyle (Cyathostominae) beta-tubulin sequences

Cited by 35 publications

References 11 publications

Recent developments in research into the Cyathostominae and Anoplocephala perfoliata

Recent developments in research into the Cyathostominae and Anoplocephala perfoliata

Analysis of codon usage in ?-tubulin sequences of helminths

Expression of recombinant β-tubulin alleles from Cylicocyclus nassatus (Cyathostominae)

Contact Info

Product

Resources

About