# name
Teladorsagia circumcincta beta tubulin: the presence of the
E198L polymorphism on its own is associated with benzimidazole
resistance.

# metadata.dc.description.abstract[].value
BACKGROUND NlmCategory: BACKGROUND content:
"Benzimidazole resistance is associated with isotype-1
 \xCE\xB2-tubulin gene F200Y, E198A and F167Y SNPs. In this
 study, the recently described polymorphism E198L was reported
                and analysed in Teladorsagia circumcincta." - Label: METHODS
                NlmCategory: METHODS content: "The benzimidazole phenotypic
                resistance was measured by the faecal egg count reduction test
                (FECRT) and the egg hatch test (EHT) using a discriminating dose
                (DD) in 39 sheep flocks. Around 1000 larvae collected before and
                after treatment were used for DNA extraction. The resistant
                species identified in all flocks was T. circumcincta. The
                resistance alleles frequencies were measured for F200Y and
                E198A. A 371-bp fragment of the isotype-1 \xCE\xB2-tubulin gene
                was analysed, including the three codons of interest, and a new
                pyrosequencing assay was designed for testing E198L." - Label:
                RESULTS NlmCategory: RESULTS content: "The percentage of
                resistant flocks was 35% by FECRT or 26% by EHT; however, F200Y
                and E198A SNPs were absent in T. circumcincta. The amplification
                of a 371-bp fragment confirmed the absence of F167Y and F200Y in
                6 resistant flocks. Regarding codon 198, all samples after
                treatment carried a leucine (CTA). A pyrosequencing assay
                analysed the allele frequencies for the first two bases at codon
                198 independently, G/C and A/T. The correlation between C and T
                frequencies was almost 1 (r\xE2\x80\x89=\xE2\x80\x890.929,
                P\xE2\x80\x89<\xE2\x80\x890.0001) and the mean value of both
                was calculated to measure the leucine frequency; this value
                ranged between 10.4-80.7% before treatment, and 82.3-92.8% after
                treatment. High and similar correlations were reported between
                the genotypic variables (C frequency, T frequency or mean of
                both frequencies) and phenotypic resistance
                (r\xE2\x80\x89>\xE2\x80\x890.720,
                P\xE2\x80\x89<\xE2\x80\x890.0001), although negatively
                associated with the FECRT and positively with the EHT. According
                to multivariate linear regression analysis, the T frequency was
                the most significant variable influencing the phenotypic
                resistance (FECRT or EHT; P\xE2\x80\x89<\xE2\x80\x890.0001).
                In the EHT, 67.1% of the phenotypic variability is associated
                with the T frequency but in the FECRT only 33.4%; therefore, the
                EHT using a DD seems to detect the genotypic resistance more
                accurately than the FECRT." - Label: CONCLUSIONS NlmCategory:
                CONCLUSIONS content: The E198L polymorphism can confer BZ
                resistance on its own in T. circumcincta.

# metadata.dc.rights[].value
cc by (c) Martínez Valladares, María et al, 2020

# metadata.dc.source[].value
Articles publicats en revistes (ISGlobal)

# metadata.dc.title[].value
Teladorsagia circumcincta beta tubulin: the presence of the
E198L polymorphism on its own is associated with benzimidazole
resistance.