Publications by authors named "Stewart T G Burgess"

36 Publications

Transcriptomic analysis of the poultry red mite, Dermanyssus gallinae, across all stages of the lifecycle.

BMC Genomics 2021 Apr 7;22(1):248. Epub 2021 Apr 7.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, EH26 0PZ, UK.

Background: The blood feeding poultry red mite (PRM), Dermanyssus gallinae, causes substantial economic damage to the egg laying industry worldwide, and is a serious welfare concern for laying hens and poultry house workers. In this study we have investigated the temporal gene expression across the 6 stages/sexes (egg, larvae, protonymph and deutonymph, adult male and adult female) of this neglected parasite in order to understand the temporal expression associated with development, parasitic lifestyle, reproduction and allergen expression.

Results: RNA-seq transcript data for the 6 stages were mapped to the PRM genome creating a publicly available gene expression atlas (on the OrcAE platform in conjunction with the PRM genome). Network analysis and clustering of stage-enriched gene expression in PRM resulted in 17 superclusters with stage-specific or multi-stage expression profiles. The 6 stage specific superclusters were clearly demarked from each other and the adult female supercluster contained the most stage specific transcripts (2725), whilst the protonymph supercluster the fewest (165). Fifteen pairwise comparisons performed between the different stages resulted in a total of 6025 Differentially Expressed Genes (DEGs) (P > 0.99). These data were evaluated alongside a Venn/Euler analysis of the top 100 most abundant genes in each stage. An expanded set of cuticle proteins and enzymes (chitinase and metallocarboxypeptidases) were identified in larvae and underpin cuticle formation and ecdysis to the protonymph stage. Two mucin/peritrophic-A salivary proteins (DEGAL6771g00070, DEGAL6824g00220) were highly expressed in the blood-feeding stages, indicating peritrophic membrane formation during feeding. Reproduction-associated vitellogenins were the most abundant transcripts in adult females whilst, in adult males, an expanded set of serine and cysteine proteinases and an epididymal protein (DEGAL6668g00010) were highly abundant. Assessment of the expression patterns of putative homologues of 32 allergen groups from house dust mites indicated a bias in their expression towards the non-feeding larval stage of PRM.

Conclusions: This study is the first evaluation of temporal gene expression across all stages of PRM and has provided insight into developmental, feeding, reproduction and survival strategies employed by this mite. The publicly available PRM resource on OrcAE offers a valuable tool for researchers investigating the biology and novel interventions of this parasite.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12864-021-07547-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8028124PMC
April 2021

RNAi gene knockdown in the poultry red mite, Dermanyssus gallinae (De Geer 1778), a tool for functional genomics.

Parasit Vectors 2021 Jan 18;14(1):57. Epub 2021 Jan 18.

Moredun Research Institute, Pentland Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, UK.

Background: The avian haematophagous ectoparasite Dermanyssus gallinae, commonly known as the poultry red mite, causes significant economic losses to the egg-laying industry worldwide and also represents a significant welfare threat. Current acaricide-based controls are unsustainable due to the mite's ability to rapidly develop resistance, thus developing a novel sustainable means of control for D. gallinae is a priority. RNA interference (RNAi)-mediated gene silencing is a valuable tool for studying gene function in non-model organisms, but is also emerging as a novel tool for parasite control.

Methods: Here we use an in silico approach to identify core RNAi pathway genes in the recently sequenced D. gallinae genome. In addition we utilise an in vitro feeding device to deliver double-stranded (ds) RNA to D. gallinae targeting the D. gallinae vATPase subunit A (Dg vATPase A) gene and monitor gene knockdown using quantitative PCR (qPCR).

Results: Core components of the small interfering RNA (siRNA) and microRNA (miRNA) pathways were identified in D. gallinae, which indicates that these gene silencing pathways are likely functional. Strikingly, the P-element-induced wimpy testis (PIWI)-interacting RNA (piRNA) pathway was absent in D. gallinae. In addition, feeding Dg vATPase A dsRNA to adult female D. gallinae resulted in silencing of the targeted gene compared to control mites fed non-specific lacZ dsRNA. In D. gallinae, dsRNA-mediated gene knockdown was rapid, being detectable 24 h after oral delivery of the dsRNA, and persisted for at least 120 h.

Conclusions: This study shows the presence of core RNAi machinery components in the D. gallinae genome. In addition, we have developed a robust RNAi methodology for targeting genes in D. gallinae that will be of value for studying genes of unknown function and validating potential control targets in D. gallinae.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-020-04562-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7813172PMC
January 2021

Early immune suppression leads to uncontrolled mite proliferation and potent host inflammatory responses in a porcine model of crusted versus ordinary scabies.

PLoS Negl Trop Dis 2020 09 4;14(9):e0008601. Epub 2020 Sep 4.

School of Health & Sport Sciences, University of the Sunshine Coast, Sippy Downs, Queensland, Australia.

Scabies is a neglected tropical disease of global significance. Our understanding of host-parasite interactions has been limited, particularly in crusted scabies (CS), a severe clinical manifestation involving hyper-infestation of Sarcoptes scabiei mites. Susceptibility to CS may be associated with immunosuppressive conditions but CS has also been seen in cases with no identifiable risk factor or immune deficit. Due to ethical and logistical difficulties with undertaking research on clinical patients with CS, we adopted a porcine model which parallels human clinical manifestations. Transcriptomic analysis using microarrays was used to explore scabies pathogenesis, and to identify early events differentiating pigs with ordinary (OS) and crusted scabies. Pigs with OS (n = 4), CS (n = 4) and non-infested controls (n = 4) were compared at pre-infestation, weeks 1, 2, 4 and 8 post-infestation. In CS relative to OS, there were numerous differentially expressed genes including pro-inflammatory cytokines (IL17A, IL8, IL19, IL20 and OSM) and chemokines involved in immune cell activation and recruitment (CCL20, CCL27 and CXCL6). The influence of genes associated with immune regulation (CD274/PD-L1 and IL27), immune signalling (TLR2, TLR8) and antigen presentation (RFX5, HLA-5 and HLA-DOB) were highlighted in the early host response to CS. We observed similarities with gene expression profiles associated with psoriasis and atopic dermatitis and confirmed previous observations of Th2/17 pronounced responses in CS. This is the first comprehensive study describing transcriptional changes associated with the development of CS and significantly, the distinction between OS and CS. This provides a basis for clinical follow-up studies, potentially identifying new control strategies for this severely debilitating disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.pntd.0008601DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508399PMC
September 2020

Psoroptes ovis-Early Immunoreactive Protein (Pso-EIP-1) a novel diagnostic antigen for sheep scab.

Parasite Immunol 2020 12 14;42(12):e12788. Epub 2020 Sep 14.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, UK.

Aims: Serodiagnosis of sheep scab is an established diagnostic method and has become popular in recent years. However, the current diagnostic antigen, Pso o 2, has shown promise as a component of a recombinant vaccine for scab, making it incompatible with discriminating between infected and vaccinated animals (DIVA). Here, we describe the discovery and characterization of a novel Psoroptes ovis immunodiagnostic antigen, P. ovis-Early Immunoreactive Protein-1 (Pso-EIP-1).

Methods And Results: Pso-EIP-1 is a highly abundant member of a six-gene family with no known homologs, indicating its potential uniqueness to P. ovis. Expression of recombinant Pso-EIP-1 (rPso-EIP-1) required a C-terminal fusion protein for stability and specific IgG immunoreactivity against rPso-EIP-1 was observed in sheep serum from 1 to 2 weeks post-infestation, indicating its highly immunogenic nature. Two of the three in silico-predicted B-cell epitopes of Pso-EIP-1 were confirmed by in vitro epitope mapping and, in a direct comparison by ELISA, Pso-EIP-1 performed to the same levels as Pso o 2 in terms of sensitivity, specificity and ability to diagnose P. ovis on sheep within 2 weeks of infestation.

Conclusion: Pso-EIP-1 represents a novel diagnostic antigen for sheep scab with comparable levels of sensitivity and specificity to the existing Pso o 2 antigen.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pim.12788DOI Listing
December 2020

Characterisation of serum IgG(T) responses to potential diagnostic antigens for equine cyathostominosis.

Int J Parasitol 2020 04 12;50(4):289-298. Epub 2020 Mar 12.

Moredun Research Institute, Pentlands Science Park, Edinburgh EH26 0PZ, United Kingdom. Electronic address:

Cyathostomins are ubiquitous parasitic nematodes of horses. These worms spend substantial periods as intestinal wall stage encysted larvae, which can comprise up to 90% of the total burden. Several million larvae have been reported in individuals. Emergence of these larvae from the gut wall can lead to life-threatening colitis. Faecal egg count tests, increasingly used by horse owners to inform anthelmintic treatments, do not correlate with the intra-host burden of cyathostomins; this represents a key gap in the diagnostic toolbox. Previously, a cyathostomin Gut Associated Larval Antigen was identified as a promising marker for the intra-host stages of infection. Here, cyathostomin Gut Associated Larval Antigen and an additional protein, Cyathostomin Immuno-diagnostic antigen, were investigated to examine their value in providing information on cyathostomin burden. ELISA analyses examined serum IgG(T) responses to recombinant proteins derived from individual cyathostomin species. Receiver Operator Characteristic curve analysis was performed on the ELISA data; proteins with the highest Area Under the Curve values were selected to test protein combinations to investigate which were the most informative in identifying the infection status of individuals. Three cocktail combinations were tested, comprising: (a) Cy-GALA proteins from two species and a Cy-CID protein from a third species (CT3), (b) Cy-GALA proteins from five species (CT5), and (c) all CT5 components, plus a Cy-CID protein from an additional species (CT6). The best predictive values for infection were obtained using CT3 and CT6, with similar values achieved for both. Proteins in CT3 are derived from the most commonly reported species, Cyathostomum catinatum, Cylicocyclus nassatus and Cylicostephanus longibursatus. This combination was selected for future development since it represents a more commercially viable format for a diagnostic test.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijpara.2020.01.004DOI Listing
April 2020

Uptake of Diagnostic Tests by Livestock Farmers: A Stochastic Game Theory Approach.

Front Vet Sci 2020 5;7:36. Epub 2020 Feb 5.

Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.

Game theory examines strategic decision-making in situations of conflict, cooperation, and coordination. It has become an established tool in economics, psychology and political science, and more recently has been applied to disease control. Used to examine vaccination uptake in human medicine, game theory shows that when vaccination is voluntary some individuals will choose to "free-ride" on the protection provided by others, resulting in insufficient coverage for control of a vaccine-preventable disease. Here, we use game theory to examine farmer uptake of a new diagnostic ELISA test for sheep scab-a highly infectious disease with an estimated cost exceeding £8M per year to the UK industry. The stochastic game models decisions made by neighboring farmers when deciding whether to adopt the newly available test, which can detect subclinical infestation. A key element of the stochastic game framework is that it allows multiple states. Depending on infestation status and test adoption decisions in the previous year, a farm may be at high, medium or low risk of infestation this year-a status which influences the decision the farmer makes and the farmer payoffs. Ultimately, each farmer's decision depends on the costs of using the diagnostic test vs. the benefits of enhanced disease control, which may only accrue in the longer term. The extent to which a farmer values short-term over long-term benefits reflects external factors such as inflation or individual characteristics such as patience. Our results show that when using realistic parameters and with a test cost around 50% more than the current clinical diagnosis, the test will be adopted in the high-risk state, but not in the low-risk state. For the medium risk state, test adoption will depend on whether the farmer takes a long-term or short-term view. We show that these outcomes are relatively robust to change in test costs and, moreover, that whilst the farmers adopting the test would not expect to see large gains in profitability, substantial reduction in sheep scab (and associated welfare implications) could be achieved in a cost-neutral way to the industry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fvets.2020.00036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7012806PMC
February 2020

A genomic analysis and transcriptomic atlas of gene expression in Psoroptes ovis reveals feeding- and stage-specific patterns of allergen expression.

BMC Genomics 2019 Oct 23;20(1):756. Epub 2019 Oct 23.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, EH26 0PZ, UK.

Background: Psoroptic mange, caused by infestation with the ectoparasitic mite, Psoroptes ovis, is highly contagious, resulting in intense pruritus and represents a major welfare and economic concern for the livestock industry Worldwide. Control relies on injectable endectocides and organophosphate dips, but concerns over residues, environmental contamination, and the development of resistance threaten the sustainability of this approach, highlighting interest in alternative control methods. However, development of vaccines and identification of chemotherapeutic targets is hampered by the lack of P. ovis transcriptomic and genomic resources.

Results: Building on the recent publication of the P. ovis draft genome, here we present a genomic analysis and transcriptomic atlas of gene expression in P. ovis revealing feeding- and stage-specific patterns of gene expression, including novel multigene families and allergens. Network-based clustering revealed 14 gene clusters demonstrating either single- or multi-stage specific gene expression patterns, with 3075 female-specific, 890 male-specific and 112, 217 and 526 transcripts showing larval, protonymph and tritonymph specific-expression, respectively. Detailed analysis of P. ovis allergens revealed stage-specific patterns of allergen gene expression, many of which were also enriched in "fed" mites and tritonymphs, highlighting an important feeding-related allergenicity in this developmental stage. Pair-wise analysis of differential expression between life-cycle stages identified patterns of sex-biased gene expression and also identified novel P. ovis multigene families including known allergens and novel genes with high levels of stage-specific expression.

Conclusions: The genomic and transcriptomic atlas described here represents a unique resource for the acarid-research community, whilst the OrcAE platform makes this freely available, facilitating further community-led curation of the draft P. ovis genome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12864-019-6082-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806590PMC
October 2019

Draft Genome Assembly of the Poultry Red Mite, .

Microbiol Resour Announc 2018 Nov 8;7(18). Epub 2018 Nov 8.

Moredun Research Institute (MRI), Edinburgh, United Kingdom.

The poultry red mite, , is a major worldwide concern in the egg-laying industry. Here, we report the first draft genome assembly and gene prediction of , based on combined PacBio and MinION long-read sequencing. The ∼959-Mb genome is predicted to encode 14,608 protein-coding genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/MRA.01221-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6256547PMC
November 2018

Gene silencing by RNA interference in the ectoparasitic mite, Psoroptes ovis.

Vet Res 2018 Nov 1;49(1):112. Epub 2018 Nov 1.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Edinburgh, EH26 0PZ, Scotland, UK.

The presence of components of the RNA interference (RNAi) pathway in Psoroptes ovis, an ectoparasitic mite responsible for psoroptic mange, was investigated through interrogation of the P. ovis genome. Homologues of transcripts representing critical elements for achieving effective RNAi in the mite, Tetranychus urticae and the model organisms Caenorhabditis elegans and Drosophila melanogaster were identified and, following the development of a non-invasive immersion method of double stranded RNA delivery, gene silencing by RNAi was successfully demonstrated in P. ovis. Significant reductions in transcript levels were achieved for three target genes which encode the Group 2 allergen (Pso o 2), mu-class glutathione S-transferase (PoGST-mu1) and beta-tubulin (Poβtub). This is the first demonstration of RNAi in P. ovis and provides a mechanism for mining transcriptomic and genomic datasets for novel control targets against this economically important ectoparasite.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13567-018-0608-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211577PMC
November 2018

Draft Genome Assembly of the Sheep Scab Mite, Psoroptes ovis.

Genome Announc 2018 Apr 19;6(16). Epub 2018 Apr 19.

Moredun Research Institute (MRI), Edinburgh, United Kingdom.

Sheep scab, caused by infestation with , is highly contagious, results in intense pruritus, and represents a major welfare and economic concern. Here, we report the first draft genome assembly and gene prediction of based on PacBio sequencing. The ∼63.2-Mb genome encodes 12,041 protein-coding genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/genomeA.00265-18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5908946PMC
April 2018

Niche-specific gene expression in a parasitic nematode; increased expression of immunomodulators in Teladorsagia circumcincta larvae derived from host mucosa.

Sci Rep 2017 08 3;7(1):7214. Epub 2017 Aug 3.

Moredun Research Institute, Edinburgh, United Kingdom.

Metazoan parasites have to survive in many different niches in order to complete their life-cycles. In the absence of reliable methods to manipulate parasite genomes and/or proteomes, identification of the molecules critical for parasite survival within these niches has largely depended on comparative transcriptomic and proteomic analyses of different developmental stages of the parasite; however, changes may reflect differences associated with transition between developmental stages rather than specific adaptations to a particular niche. In this study, we compared the transcriptome of two fourth-stage larval populations of the nematode parasite, Teladorsagia circumcincta, which were of the same developmental stage but differed in their location within the abomasum, being either mucosal-dwelling (MD) or lumen-dwelling (LD). Using RNAseq, we identified 57 transcripts which were significantly differentially expressed between MD and LD larvae. Of these transcripts, the majority (54/57) were up-regulated in MD larvae, one of which encoded for an ShKT-domain containing protein, Tck6, capable of modulating ovine T cell cytokine responses. Other differentially expressed transcripts included homologues of ASP-like proteins, proteases, or excretory-secretory proteins of unknown function. Our study demonstrates the utility of niche- rather than stage-specific analysis of parasite transcriptomes to identify parasite molecules of potential importance for survival within the host.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-07092-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543109PMC
August 2017

Gene silencing by RNA interference in Sarcoptes scabiei: a molecular tool to identify novel therapeutic targets.

Parasit Vectors 2017 Jun 10;10(1):289. Epub 2017 Jun 10.

QIMR Berghofer Medical Research Institute, Infectious Diseases Department, 300 Herston Road, Herston, Brisbane, 4006, Australia.

Background: Scabies is one of the most common and widespread parasitic skin infections globally, affecting a large range of mammals including humans, yet the molecular biology of Sarcoptes scabiei is astonishingly understudied. Research has been hampered primarily due to the difficulty of sampling or culturing these obligatory parasitic mites. A further and major impediment to identify and functionally analyse potential therapeutic targets from the recently emerging molecular databases is the lack of appropriate molecular tools.

Methods: We performed standard BLAST based searches of the existing S. scabiei genome databases using sequences of genes described to be involved in RNA interference in Drosophila and the mite model organism Tetranychus urticae. Experimenting with the S. scabiei mu-class glutathione S-transferase (SsGST-mu1) as a candidate gene we explored the feasibility of gene knockdown in S. scabiei by double-stranded RNA-interference (dsRNAi).

Results: We provide here an analysis of the existing S. scabiei draft genomes, confirming the presence of a double stranded RNA (dsRNA) - mediated silencing machinery. We report for the first time experimental gene silencing by RNA interference (RNAi) in S. scabiei. Non-invasive immersion of S. scabiei in dsRNA encoding an S. scabiei glutathione S-transferase mu-class 1 enzyme (SsGST-mu1) resulted in a 35% reduction in the transcription of the target gene compared to controls.

Conclusions: A series of experiments identified the optimal conditions allowing systemic experimental RNAi without detrimental side effects on mite viability. This technique can now be used to address the key questions on the fundamental aspects of mite biology and pathogenesis, and to assess the potential therapeutic benefits of silencing S. scabiei target genes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-017-2226-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5466799PMC
June 2017

Opportunities and challenges for the application of microfluidic technologies in point-of-care veterinary diagnostics.

Mol Cell Probes 2016 10 16;30(5):331-341. Epub 2016 Jul 16.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, EH26 0PZ, United Kingdom. Electronic address:

There is a growing need for low-cost, rapid and reliable diagnostic results in veterinary medicine. Point-of-care (POC) tests have tremendous advantages over existing laboratory-based tests, due to their intrinsic low-cost and rapidity. A considerable number of POC tests are presently available, mostly in dipstick or lateral flow formats, allowing cost-effective and decentralised diagnosis of a wide range of infectious diseases and public health related threats. Although, extremely useful, these tests come with some limitations. Recent advances in the field of microfluidics have brought about new and exciting opportunities for human health diagnostics, and there is now great potential for these new technologies to be applied in the field of veterinary diagnostics. This review appraises currently available POC tests in veterinary medicine, taking into consideration their usefulness and limitations, whilst exploring possible applications for new and emerging technologies, in order to widen and improve the range of POC tests available.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcp.2016.07.004DOI Listing
October 2016

Investigation and treatment of ovine psoroptic otoacariasis.

Vet Dermatol 2016 Jun;27(3):206-e52

Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK.

Background: Psoroptic otoacariasis has been described worldwide and is caused by a mite morphologically indistinguishable from the sheep scab mite Psoroptes ovis. A single treatment of affected sheep with 200 μg/kg of injectable ivermectin is reported to be curative.

Case Report: Psoroptes mites were isolated following treatment with ivermectin, but treatment with moxidectin at 1 mg/kg caused complete cessation of clinical signs. Affected animals were seropositive to Pso o 2 antigen enzyme-linked immunosorbent assay (ELISA) and had serum haptoglobin concentrations that overlapped with those described for field infections of classical sheep scab.

Conclusions And Clinical Importance: Psoroptic otoacariasis is not controlled by single treatments of injectable ivermectin but resolves after a single treatment with injectable moxidectin. Pso o 2 ELISA can detect infection with Psoroptes spp. mites but cannot distinguish between sheep scab and psoroptic otoacariasis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/vde.12314DOI Listing
June 2016

Development of a recombinant protein-based ELISA for diagnosis of larval cyathostomin infection.

Parasitology 2016 07 13;143(8):1055-66. Epub 2016 May 13.

Moredun Research Institute,Pentlands Science Park,Edinburgh EH26 0PZ,Scotland,UK.

Cyathostomins are ubiquitous nematodes of horses. Once ingested, they can spend a substantial time as encysted larvae in the intestinal wall. The larvae can comprise up to 90% of the total burden, with up to several million worms reported in individuals. These stages can emerge in large numbers to cause life-threatening colitis. Direct methods for detection of encysted larval burdens in live horses do not exist. Previously, two antigen complexes were identified as promising markers for infection. A component of these, cyathostomin gut associated larval antigen-1 (Cy-GALA-1), was identified following immunoscreening of a complementary DNA library. Serum immunoglobulin G(T) (IgG(T)) responses to Cy-GALA-1 were shown to inform on larval infection. Sequence analysis of polymerase chain reaction products amplified from individual worms indicated that Cy-GALA-1 was derived from Cyathostomum pateratum. As cyathostomin infections always comprise multiple species, a diagnostic test must account for this. Here, segments of the Cy-gala gene were isolated from four common species, Cyathostomum catinatum, Cylicocyclus ashworthi, Cylicostephanus goldi and Cylicostephanus longibursatus, and the associated proteins expressed in recombinant form. The specificity and immunogenicity of each protein was confirmed. Each protein was assessed by enzyme linked immuno sorbent assay (ELISA) for its ability for informing on the presence of encysted larval infection and the level of burden.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1017/S0031182016000627DOI Listing
July 2016

A recombinant subunit vaccine for the control of ovine psoroptic mange (sheep scab).

Vet Res 2016 Feb 9;47:26. Epub 2016 Feb 9.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.

Sheep scab, caused by infestation with the mite Psoroptes ovis, is highly contagious, causing intense pruritus and represents a major welfare and economic concern. Disease control strategies rely upon chemotherapy, however, sustainability is questionable due to issues of chemical residues, eco-toxicity and acaricide resistance. Control by vaccination is supported by demonstration of protective immunity in sheep previously infested with P. ovis. We identified vaccine candidates for P. ovis based on: (1) antigens selected by their interaction with host signalling pathways and the host immune-response; and (2) those shown to be either immunogenic or involved in mite feeding. This resulted in the development and validation, in repeated immunisation and challenge trials, of a seven recombinant protein sub-unit cocktail vaccine. Sheep were inoculated on three occasions, 2 weeks apart, along with QuilA adjuvant. Vaccination resulted in highly significant reductions in both lesion size (up to 63%) and mite numbers (up to 56%) following challenge. Mean lesion size in vaccinates was significantly smaller than controls from 1 week post infestation (wpi) until the end of the experiment at 6 wpi. All antigens elicited serum IgG responses following immunisation and prior to infestation, whereas controls did not produce antigen-specific IgG during the pre-infestation period. Vaccinated animals showed an amnestic response, with levels of antigen-specific IgG against muGST, Pso o 1 and Pso o 2 increasing following infestation. This vaccine represents the greatest reduction in lesion size to date with a sheep scab vaccine, providing encouragement for future production of a commercially-viable means of immunoprophylaxis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13567-016-0315-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4748516PMC
February 2016

Gene silencing by RNA interference in the house dust mite, Dermatophagoides pteronyssinus.

Mol Cell Probes 2015 Dec 26;29(6):522-526. Epub 2015 Jul 26.

Division of Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Edinburgh, Scotland, United Kingdom. Electronic address:

This is the first report of gene silencing by RNA interference (RNAi) in the European house dust mite, Dermatophagoides pteronyssinus, Trouessart, 1897. Using a non-invasive immersion method first developed for the honey bee mite, Varroa destructor, a significant reduction in the expression of D. pteronyssinus glutathione-S-transferase mu-class 1 enzyme (DpGST-mu1) was achieved following overnight immersion in double stranded RNA encoding DpGST-mu1. Although no detrimental phenotypic changes were observed following silencing, this technique can now be used to address fundamental physiological questions and assess the potential therapeutic benefit in silencing D. pteronyssinus target genes in selected domestic situations of high human-mite interface.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcp.2015.07.008DOI Listing
December 2015

Two major ruminant acute phase proteins, haptoglobin and serum amyloid A, as serum biomarkers during active sheep scab infestation.

Vet Res 2013 Oct 31;44:103. Epub 2013 Oct 31.

Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, UK.

Two ruminant acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid A (SAA), were evaluated as serum biomarkers (BMs) for sheep scab-a highly contagious ectoparasitic disease caused by the mite Psoroptes ovis, which is a major welfare and production threat worldwide. The levels of both APPs increased in serum following experimental infestation of sheep with P. ovis, becoming statistically significantly elevated from pre-infestation levels at 4 weeks post-infestation. Following successful treatment of infested sheep with an endectocide, Hp and SAA serum levels declined rapidly, with half lives of less than 3 days. In contrast, serum IgG levels which specifically bound the P. ovis-derived diagnostic antigen Pso o 2 had a half-life of 56 days. Taking into account pre-infestation serum levels, rapidity of response to infestation and test sensitivity at the estimated optimum cut-off values, SAA was the more discriminatory marker. These studies illustrated the potential of SAA and Hp to indicate current sheep scab infestation status and to augment the existing Pso o 2 serological assay to give disease-specific indications of both infestation and successful treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1297-9716-44-103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3832035PMC
October 2013

Characterization of the ovine complement 4 binding protein-beta (C4BPB) chain as a serum biomarker for enhanced diagnosis of sheep scab.

Mol Cell Probes 2013 Jun-Aug;27(3-4):158-63. Epub 2013 Mar 28.

Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, United Kingdom.

Sheep scab, caused by the highly contagious mite Psoroptes ovis, is endemic in a number of sheep-producing countries worldwide, and is a major animal welfare and economic concern. Recent developments in the diagnosis of sheep scab include a highly sensitive and specific serum antibody-based assay which can be used to indicate exposure to the parasite but not necessarily current disease status. Here, a transcriptomic and bioinformatics analysis of the circulating leukocytes of sheep with active P. ovis infestation indicated that the transcription levels of complement 4 binding protein beta (C4BPB) increased by 12 fold from pre-infestation to 6 weeks post-infestation. Semi-quantitative studies confirmed increased serum C4BPB protein levels in sheep infested with P. ovis. To quantify this serum protein response and characterize ovine C4BPB as a biomarker for active P. ovis infestation, the ovine C4BPB gene was sequenced, a recombinant protein expressed, antibodies against this protein were raised in rabbits and a sandwich ELISA developed. The results from this assay indicated that serum C4BPB protein levels increased 4-fold from pre-infestation to 6 weeks post-infestation, which demonstrated the potential of the assay to quantify C4BPB in sheep sera and indicated the potential of C4BPB as a biomarker of current disease status in sheep post-infestation and post-treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcp.2013.03.003DOI Listing
April 2014

The effect of Psoroptes ovis infestation on ovine epidermal barrier function.

Vet Res 2013 Feb 11;44:11. Epub 2013 Feb 11.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, United Kingdom.

Sheep scab is an intensively pruritic, exudative and allergic dermatitis of sheep caused by the ectoparasitic mite Psoroptes ovis. The purpose of the present study was to investigate the effect of P. ovis infestation on different components of the ovine epidermal barrier within the first 24 hours post-infestation (hpi). To achieve this, the expression of epidermal differentiation complex (EDC) genes and epidermal barrier proteins, the nature and severity of epidermal pathology and transepidermal water loss (TEWL) were evaluated.By 1 hpi a significant dermal polymorphonuclear infiltrate and a significant increase in TEWL with maximal mean TEWL (598.67 g/m2h) were observed. Epidermal pathology involving intra-epidermal pustulation, loss of epidermal architecture and damage to the basement membrane was seen by 3 hpi. Filaggrin and loricrin protein levels in the stratum corneum declined significantly in the first 24 hpi and qPCR validation confirmed the decrease in expression of the key EDC genes involucrin, filaggrin and loricrin observed by microarray analysis, with 5.8-fold, 4.5-fold and 80-fold decreases, respectively by 24 hpi.The present study has demonstrated that early P. ovis infestation disrupts the ovine epidermal barrier causing significant alterations in the expression of critical barrier components, epidermal pathology, and TEWL. Many of these features have also been documented in human and canine atopic dermatitis suggesting that sheep scab may provide a model for the elucidation of events occurring in the early phases of atopic sensitisation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1297-9716-44-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599485PMC
February 2013

Transcriptomic analysis of circulating leukocytes reveals novel aspects of the host systemic inflammatory response to sheep scab mites.

PLoS One 2012 3;7(8):e42778. Epub 2012 Aug 3.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, United Kingdom.

Infestation of ovine skin with the ectoparasitic mite Psoroptes ovis results in the development of a rapid cutaneous inflammatory response, leading to the crusted skin lesions characteristic of sheep scab. To facilitate the identification of novel diagnostic and therapeutic targets, a better understanding of the host-parasite relationship in sheep scab is essential. Although our knowledge of the host's local cutaneous inflammatory response to sheep scab has increased in recent years, we still know relatively little about the mechanisms of this response at the systemic level. This study used a combined network and pathway analysis of the in vivo transcriptomic response of circulating leukocytes to infestation with P. ovis, during a 6 week period. Network graph analysis identified six temporally-associated gene clusters, which separated into two distinct sub-networks within the graph, representing those genes either up or down-regulated during the time course. Functional and pathway analysis of these clusters identified novel insights into the host systemic response to P. ovis infestation, including roles for the complement system, clotting cascade and fibrinolysis. These analyses also highlighted potential mechanisms by which the systemic immune response to sheep scab can influence local tissue responses via enhanced leukocyte activation and extravasation. By analysing the transcriptomic responses of circulating leukocytes in sheep following infestation with P. ovis, this study has provided key insights into the inflammatory response to infestation and has also demonstrated the utility of these cells as a proxy of events occurring at local tissue sites, providing insight into the mechanisms by which a local allergen-induced inflammatory response may be controlled.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0042778PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3411848PMC
January 2013

Intestinal proteases of free-living and parasitic astigmatid mites.

Cell Tissue Res 2013 Feb 17;351(2):339-52. Epub 2012 Mar 17.

Menzies School of Health Research, Charles Darwin University, PO Box 41096, Casuarina, NT, 0811, Australia.

Among arthropod pests, mites are responsible for considerable damage to crops, humans and other animals. However, detailed physiological data on these organisms remain sparse, mainly because of their small size but possibly also because of their extreme diversity. Focusing on intestinal proteases, we draw together information from three distinct mite species that all feed on skin but have separately adapted to a free-living, a strictly ecto-parasitic and a parasitic lifestyle. A wide range of studies involving immunohistology, molecular biology, X-ray crystallography and enzyme biochemistry of mite gut proteases suggests that these creatures have diverged considerably as house dust mites, sheep scab mites and scabies mites. Each species has evolved a particular variation of a presumably ancestral repertoire of digestive enzymes that have become specifically adapted to their individual environmental requirements.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00441-012-1369-9DOI Listing
February 2013

Development of a cDNA microarray for the measurement of gene expression in the sheep scab mite Psoroptes ovis.

Parasit Vectors 2012 Feb 8;5:30. Epub 2012 Feb 8.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, UK.

Background: Sheep scab is caused by the ectoparasitic mite Psoroptes ovis which initiates a profound cutaneous inflammatory response, leading to the development of the skin lesions which are characteristic of the disease. Existing control strategies rely upon injectable endectocides and acaricidal dips but concerns over residues, eco-toxicity and the development of acaricide resistance limit the sustainability of this approach. In order to identify alternative means of disease control, a deeper understanding of both the parasite and its interaction with the host are required.

Methods: Herein we describe the development and utilisation of an annotated P. ovis cDNA microarray containing 3,456 elements for the measurement of gene expression in this economically important ectoparasite. The array consists of 981 P. ovis EST sequences printed in triplicate along with 513 control elements. Array performance was validated through the analysis of gene expression differences between fed and starved P. ovis mites.

Results: Sequences represented on the array include homologues of major house dust mite allergens and tick salivary proteins, along with factors potentially involved in mite reproduction and xenobiotic metabolism. In order to validate the performance of this unique resource under biological conditions we used the array to analyse gene expression differences between fed and starved P. ovis mites. These analyses identified a number of house dust mite allergen homologues up-regulated in fed mites and P. ovis transcripts involved in stress responses, autophagy and chemosensory perception up-regulated in starved mites.

Conclusion: The P. ovis cDNA microarray described here has been shown to be both robust and reproducible and will enable future studies to analyse gene expression in this important ectoparasite.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-3305-5-30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296576PMC
February 2012

The use of a Psoroptes ovis serodiagnostic test for the analysis of a natural outbreak of sheep scab.

Parasit Vectors 2012 Jan 10;5. Epub 2012 Jan 10.

Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, EH26 0PZ, Scotland, UK.

Background: Sheep scab is a highly contagious disease of sheep caused by the ectoparasitic mite Psoroptes ovis. The disease is endemic in the UK and has significant economic impact through its effects on performance and welfare. Diagnosis of sheep scab is achieved through observation of clinical signs e.g. itching, pruritis and wool loss and ultimately through the detection of mites in skin scrapings. Early stages of infestation are often difficult to diagnose and sub-clinical animals can be a major factor in disease spread. The development of a diagnostic assay would enable farmers and veterinarians to detect disease at an early stage, reducing the risk of developing clinical disease and limiting spread.

Methods: Serum samples were obtained from an outbreak of sheep scab within an experimental flock (n = 480 (3 samples each from 160 sheep)) allowing the assessment, by ELISA of sheep scab specific antibody prior to infestation, mid-outbreak (combined with clinical assessment) and post-treatment.

Results: Analysis of pre-infestation samples demonstrated low levels of potential false positives (3.8%). Of the 27 animals with clinical or behavioural signs of disease 25 tested positive at the mid-outbreak sampling period, however, the remaining 2 sheep tested positive at the subsequent sampling period. Clinical assessment revealed the absence of clinical or behavioural signs of disease in 132 sheep, whilst analysis of mid-outbreak samples showed that 105 of these clinically negative animals were serologically positive, representing potential sub-clinical infestations.

Conclusions: This study demonstrates that this ELISA test can effectively diagnose sheep scab in a natural outbreak of disease, and more importantly, highlights its ability to detect sub-clinically infested animals. This ELISA, employing a single recombinant antigen, represents a major step forward in the diagnosis of sheep scab and may prove to be critical in any future control program.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-3305-5-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3266638PMC
January 2012

Quantitative PCR-based genome size estimation of the astigmatid mites Sarcoptes scabiei, Psoroptes ovis and Dermatophagoides pteronyssinus.

Parasit Vectors 2012 Jan 4;5. Epub 2012 Jan 4.

Infectious Diseases Division, Queensland Institute of Medical Research, PO Royal Brisbane Hospital, QLD, 4029 Australia.

Background: The lack of genomic data available for mites limits our understanding of their biology. Evolving high-throughput sequencing technologies promise to deliver rapid advances in this area, however, estimates of genome size are initially required to ensure sufficient coverage.

Methods: Quantitative real-time PCR was used to estimate the genome sizes of the burrowing ectoparasitic mite Sarcoptes scabiei, the non-burrowing ectoparasitic mite Psoroptes ovis, and the free-living house dust mite Dermatophagoides pteronyssinus. Additionally, the chromosome number of S. scabiei was determined by chromosomal spreads of embryonic cells derived from single eggs.

Results: S. scabiei cells were shown to contain 17 or 18 small (< 2 μM) chromosomes, suggesting an XO sex-determination mechanism. The average estimated genome sizes of S. scabiei and P. ovis were 96 (± 7) Mb and 86 (± 2) Mb respectively, among the smallest arthropod genomes reported to date. The D. pteronyssinus genome was estimated to be larger than its parasitic counterparts, at 151 Mb in female mites and 218 Mb in male mites.

Conclusions: This data provides a starting point for understanding the genetic organisation and evolution of these astigmatid mites, informing future sequencing projects. A comparitive genomic approach including these three closely related mites is likely to reveal key insights on mite biology, parasitic adaptations and immune evasion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-3305-5-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3274472PMC
January 2012

Recent developments in the diagnosis of ectoparasite infections and disease through a better understanding of parasite biology and host responses.

Mol Cell Probes 2012 Feb 1;26(1):47-53. Epub 2011 Oct 1.

Moredun Research Institute, Pentlands Science Park, Midlothian EH26 0PZ, United Kingdom.

Some conventional methods of diagnosis of ectoparasite infections can have low sensitivity and/or specificity. In addition, early infestations, sub-clinical and carrier hosts often go un-diagnosed, allowing infestations to spread. This review focuses on the important ectoparasites of human, livestock and companion animals for which improved diagnostic tools are either already in use, or in development. These advances in diagnostic technologies have resulted in improved treatment, control and preventative strategies for many ectoparasitic diseases. Immunodiagnostic methods have had a large impact, with the emergence of highly sensitive and specific enzyme-linked immunosorbent assays (ELISAs) for sarcoptic and psoroptic mange, with further improved tests in development. In the present review, the advantages and limitations of such tests are discussed and the potential for future development explored. The increasing use of molecular tools, for example, PCR and other molecular methods, has improved our understanding of the epidemiology of ectoparasitic diseases, with practical consequences for community-based control programmes. Recently, the identification of specific signalling pathways during the host response to ectoparasites has led to the identification of disease biomarkers which, along with new technologies, such as multiplexed assays and microfluidic platforms, could lead to more cost-effective, rapid and accurate diagnosis of infectious diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcp.2011.07.002DOI Listing
February 2012

Development of a serodiagnostic test for sheep scab using recombinant protein Pso o 2.

Mol Cell Probes 2011 Oct-Dec;25(5-6):212-8. Epub 2011 Sep 22.

Division of Parasitology, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 0PZ, Scotland, UK.

Early stages of sheep scab, the disease caused by the non-burrowing mite Psoroptes ovis, are often sub-clinical, or can be mis-diagnosed. A diagnostic test capable of detecting early disease and latent infestations is therefore highly desirable in disease control. This paper describes the design and validation of an ELISA, which incorporates a recombinant P. ovis antigen (Pso o 2), for the early detection of anti-P. ovis serum antibodies in sheep. This ELISA was evaluated using sera from sheep infested with P. ovis (n = 58) and sheep (n = 433) with no P. ovis infestation as well as sheep infected with other parasites including gastrointestinal nematodes (GIN), or chewing lice. A receiver operating characteristic (ROC) curve analysis was generated using the ELISA results for 491 sheep sera with the area under the curve (AUC) being 0.97. An optimal OD(450) cut-off of >0.06 absorbance units gave a test sensitivity of 0.93 and specificity of 0.90. The Pso o 2-based ELISA was able to detect specific antibodies to P. ovis during early experimental infestation prior to disease patency, indicating its utility for detecting sub-clinical infestation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mcp.2011.09.002DOI Listing
February 2012

Host transcription factors in the immediate pro-inflammatory response to the parasitic mite Psoroptes ovis.

PLoS One 2011 7;6(9):e24402. Epub 2011 Sep 7.

Moredun Research Institute, Pentlands Science Park, Edinburgh, Scotland, United Kingdom.

Background: Sheep scab, caused by infestation with the ectoparasitic mite Psoroptes ovis, results in the rapid development of cutaneous inflammation and leads to the crusted skin lesions characteristic of the disease. We described previously the global host transcriptional response to infestation with P. ovis, elucidating elements of the inflammatory processes which lead to the development of a rapid and profound immune response. However, the mechanisms by which this response is instigated remain unclear. To identify novel methods of intervention a better understanding of the early events involved in triggering the immune response is essential. The objective of this study was to gain a clearer understanding of the mechanisms and signaling pathways involved in the instigation of the immediate pro-inflammatory response.

Results: Through a combination of transcription factor binding site enrichment and pathway analysis we identified key roles for a number of transcription factors in the instigation of cutaneous inflammation. In particular, defined roles were elucidated for the transcription factors NF-kB and AP-1 in the orchestration of the early pro-inflammatory response, with these factors being implicated in the activation of a suite of inflammatory mediators.

Conclusions: Interrogation of the host temporal response to P. ovis infestation has enabled the further identification of the mechanisms underlying the development of the immediate host pro-inflammatory response. This response involves key regulatory roles for the transcription factors NF-kB and AP-1. Pathway analysis demonstrated that the activation of these transcription factors may be triggered following a host LPS-type response, potentially involving TLR4-signalling and also lead to the intriguing possibility that this could be triggered by a P. ovis allergen.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0024402PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3168495PMC
February 2012

Generation, analysis and functional annotation of expressed sequence tags from the ectoparasitic mite Psoroptes ovis.

Parasit Vectors 2011 Jul 22;4:145. Epub 2011 Jul 22.

Division of Parasitology, Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, UK.

Background: Sheep scab is caused by Psoroptes ovis and is arguably the most important ectoparasitic disease affecting sheep in the UK. The disease is highly contagious and causes and considerable pruritis and irritation and is therefore a major welfare concern. Current methods of treatment are unsustainable and in order to elucidate novel methods of disease control a more comprehensive understanding of the parasite is required. To date, no full genomic DNA sequence or large scale transcript datasets are available and prior to this study only 484 P. ovis expressed sequence tags (ESTs) were accessible in public databases.

Results: In order to further expand upon the transcriptomic coverage of P. ovis thus facilitating novel insights into the mite biology we undertook a larger scale EST approach, incorporating newly generated and previously described P. ovis transcript data and representing the largest collection of P. ovis ESTs to date. We sequenced 1,574 ESTs and assembled these along with 484 previously generated P. ovis ESTs, which resulted in the identification of 1,545 unique P. ovis sequences. BLASTX searches identified 961 ESTs with significant hits (E-value < 1E-04) and 584 novel P. ovis ESTs. Gene Ontology (GO) analysis allowed the functional annotation of 880 ESTs and included predictions of signal peptide and transmembrane domains; allowing the identification of potential P. ovis excreted/secreted factors, and mapping of metabolic pathways.

Conclusions: This dataset currently represents the largest collection of P. ovis ESTs, all of which are publicly available in the GenBank EST database (dbEST) (accession numbers FR748230 - FR749648). Functional analysis of this dataset identified important homologues, including house dust mite allergens and tick salivary factors. These findings offer new insights into the underlying biology of P. ovis, facilitating further investigations into mite biology and the identification of novel methods of intervention.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1756-3305-4-145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3154158PMC
July 2011

Genome-wide transcriptomic analysis of intestinal tissue to assess the impact of nutrition and a secondary nematode challenge in lactating rats.

PLoS One 2011 16;6(6):e20771. Epub 2011 Jun 16.

Animal Health Group, Scottish Agricultural College, Bush Estate, Penicuik, United Kingdom.

Background: Gastrointestinal nematode infection is a major challenge to the health and welfare of mammals. Although mammals eventually acquire immunity to nematodes, this breaks down around parturition, which renders periparturient mammals susceptible to re-infection and an infection source for their offspring. Nutrient supplementation reduces the extent of periparturient parasitism, but the underlying mechanisms remain unclear. Here, we use a genome wide approach to assess the effects of protein supplementation on gene expression in the small intestine of periparturient rats following nematode re-infection.

Methodology/principal Findings: The use of a rat whole genome expression microarray (Affymetrix Gene 1.0ST) showed significant differential regulation of 91 genes in the small intestine of lactating rats, re-infected with Nippostrongylus brasiliensis compared to controls; affected functions included immune cell trafficking, cell-mediated responses and antigen presentation. Genes with a previously described role in immune response to nematodes, such as mast cell proteases, and intelectin, and others newly associated with nematode expulsion, such as anterior gradient homolog 2 were identified. Protein supplementation resulted in significant differential regulation of 64 genes; affected functions included protein synthesis, cellular function and maintenance. It increased cell metabolism, evident from the high number of non-coding RNA and the increased synthesis of ribosomal proteins. It regulated immune responses, through T-cell activation and proliferation. The up-regulation of transcription factor forkhead box P1 in unsupplemented, parasitised hosts may be indicative of a delayed immune response in these animals.

Conclusions/significance: This study provides the first evidence for nutritional regulation of genes related to immunity to nematodes at the site of parasitism, during expulsion. Additionally it reveals genes induced following secondary parasite challenge in lactating mammals, not previously associated with parasite expulsion. This work is a first step towards defining disease predisposition, identifying markers for nutritional imbalance and developing sustainable measures for parasite control in domestic mammals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0020771PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116830PMC
November 2011
-->