Identification of a mutation in the para-sodium channel gene of the cattle tick Rhipicephalus (Boophilus) microplus associated with resistance to synthetic pyrethroid acaricides

Resistance against synthetic pyrethroid (SP) products for the control of cattle ticks in Australia was detected in the field in 1984, within a very short time of commercial introduction. We have identified a mutation in the domain II S4-5 linker of the para-sodium channel that is associated with resistance to SPs in the cattle tick Rhipicephalus (Boophilus) microplus from Australia. The cytosine to adenine mutation at position 190 in the R. microplus sequence AF134216, results in an amino acid substitution from leucine in the susceptible strain to isoleucine in the resistant strain. A similar mutation has been shown to confer SP resistance in the whitefly, Bemisia tabaci, but has not been described previously in ticks. A diagnostic quantitative PCR assay has been developed using allele-specific Taqman® minor groove-binding (MGB) probes. Using the assay to screen field and laboratory populations of ticks showed that homozygote allelic frequencies correlated highly with the survival percentage at the discriminating concentration of cypermethrin

Microarray evidence for off target effects in tick RNA interference experiments, and the lack of strong correlation between DSRNA and antibody phenotypes in tick In vitro treatments for vaccine candidate screening

No abstract availabl

Genome sequences of six Wheat-infecting fusarium species isolates

Fusarium pathogens represent a major constraint to wheat and barley production worldwide. To facilitate future comparative studies of Fusarium species that are pathogenic to wheat, the genome sequences of four Fusarium pseudograminearum isolates, a single Fusarium acuminatum isolate, and an organism from the Fusarium incarnatum-F. equiseti species complex are reported

CattleTickBase: An integrated Internet-based bioinformatics resource for Rhipicephalus (Boophilus) microplus

The Rhipicephalus microplus genome is large and complex in structure, making it difficult to assemble a genome sequence and costly to resource the required bioinformatics. In light of this, a consortium of international collaborators was formed to pool resources to begin sequencing this genome. We have acquired and assembled genomic DNA into contigs that represent over 1.8 Gigabase pairs of DNA from gene-enriched regions of the R. microplus genome. We also have several datasets containing transcript sequences from a number of gene expression experiments conducted by the consortium. A web-based resource was developed to enable the scientific community to access our datasets and conduct analysis through a web-based bioinformatics environment called YABI. The collective bioinformatics resource is termed CattleTickBase. Our consortium has acquired genomic and transcriptomic sequence data at approximately 0.9X coverage of the gene-coding regions of the R. microplus genome. The YABI tool will facilitate access and manipulation of cattle tick genome sequence data as the genome sequencing of R. microplus proceeds. During this process the CattleTickBase resource will continue to be updated

Genomic prediction of a B cell epitopes (HBPs) conserved among Histamine Binding proteins from Rhipicephalus microplus, study of HBPs - host interactions and anti-HBPs antibodys’ effects on adult ticks in vitro.

Oral Presentatio

Molecular detection of resistance to synthetic pyrethroid acaricides in the Australian cattle tick, Rhipicephalus (Boophilus) microplus

No abstract availabl

In silico prediction of tick vaccine candidates

The control of Rhipicephalus (Boophilus) microplus infestations and costs incurred through productions losses amount to $175m per annum for the Australian beef industry and an estimated US$2.5 billion dollars worldwide. A new vaccine for the prevention and control of infestations has been identified as a high research priority. Here we present results of our reverse vaccinology approach that has been used to identify potential vaccine candidates through a combination of an in silico analysis and gene expression studies by quantitative real-time PCR (qPCR)

Up-regulated expression of Interleukin-2 Receptor alpha in tick resistant cattle

The cattle tick Rhipicephalus microplus is responsible for severe production losses to the cattle industry worldwide. Bos indicus cattle are naturally more resistant to R. microplus than B. taurus, however, the mechanism of this resistance is relatively unknown. Pre-exposed B. taurus and B. indicus cattle were artificially infested weekly with tick larvae for 6 weeks. B. indicus cattle carried significantly fewer ticks (P=0.000) than the B. taurus cattle. Peripheral blood samples were collected to examine gene expression (Affymetrix microarrays), to analyse markers on circulating leukocytes, and to prepare lymphocyte cell cultures. IL-2 is a T cell growth regulator and a central immune system regulator. IL-2R alpha delivers IL-2 to the signalling complex and acts as a regulator of signal transduction. B. indicus cattle demonstrated a significant increase in the percentage of cells positive for the IL-2R-alpha surface marker and significantly higher IL-2R-alpha gene expression in the peripheral blood, than did the B. taurus cattle. In vitro cell cultures from B. indicus cattle had significantly higher expression of IL-2R-alpha mRNA than B. taurus cells when stimulated with tick extract. To further study this gene, siRNAs targeting IL-2R-alpha were introduced into tick stimulated in vitro cultures and IL-2R-alpha expression was partially silenced in B. taurus lymphocytes but not in B. indicus. Identifying the immune pathways employed by tick resistant cattle is an essential step for the development of anti-tick vaccines that promote an appropriate immune response to infestation