Overcoming liver fluke as a constraint to ruminant production in South-East Asia
- Authors: Piedrafita, David , Estuningsih, Endah , Spithill, Terry , Pleasance, Jill , Widjajanti, Sri , Suharyanta, S. , Partoutomo, Sutijono , Kingsford, Nicola , Hansen, D. , Clery, Dianne , Prowse, Rhoda , Meeusen, Els , Raadsma, Herman
- Date: 2008
- Type: Text , Book
- Full Text: false
- Reviewed:
Immune mechanisms of resistance to gastrointestinal nematode infections in sheep
- Authors: Hein, W. , Pernthaner, A. , Piedrafita, David , Meeusen, Els
- Date: 2010
- Type: Text , Journal article
- Relation: Parasite Immunology Vol. 32, no. 8 (2010), p. 541-548
- Full Text: false
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- Description: Infections with gastrointestinal nematode parasites are a major problem for the sheep industry in Australia and New Zealand and have been the subject of intensive research to define mechanisms of resistance. The ability to take continuous biopsy samples of infected organs and cannulate both afferent and efferent lymphatics of draining lymph nodes has been particularly useful in illuminating the kinetics of immune responses at the site of infection. Distinct localized immune responses were shown to occur within and between sheep breeds at different sensitization regimes, as well as at different developmental stages of the parasite within the host. Using localized antibodies derived from mucus and lymph nodes, two major antigens have been identified on the infective L3 stage, which may be responsible for inducing protection and have potential as vaccine targets. Recent advances in sheep genomics also offer the potential of gaining further insight into the underlying genetics of resistance to nematode infections.
Fecundity in adult Haemonchus contortus parasites is correlated with abomasal tissue eosinophils and gamma-delta T cells in resistant Canaria Hair Breed sheep
- Authors: Gonzalez, Jorge , Hernandez, Alvaro , Meeusen, Els , Rodríguez, Francisco , Molina, Jose , Jaber, Jose , Raadsma, Herman , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 178, no. 3-4 (2011), p. 286-292
- Full Text: false
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- Description: Canaria Hair Breed (CHB) sheep are more resistant than Canaria sheep (CS) to experimental Haemonchus contortus infection. Protective responses appear effective against the adult stage of the parasite, not as commonly reported in other breeds against the larval stages. In this study we have quantified several abomasal immune cells and correlated these with parasitological variables for each breed. A significant negative correlation between CD4+ T cell numbers and worm burden or length at 28 dpi was seen only in CS sheep. Significant negative correlations for both abomasal eosinophils and
Vaccination against fasciolosis by a multivalent vaccine of stage-specific antigens
- Authors: Jayaraj, Ramamoorthi , Piedrafita, David , Dynon, Kemperley , Grams, Rudi , Spithill, Terry , Smooker, Peter
- Date: 2008
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 160, no. 3-4 (2008), p. 230-236
- Full Text: false
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- Description: Liver flukes produce cathepsin B and cathepsin L in their excretory–secretory material. These proteases are proposed to be key virulence factors for parasite infection, and are therefore targets for vaccination. Cathepsin B is predominately released in the juvenile stage of the life cycle, while different cathepsin L's are released throughout the cycle. Three proteases (cathepsin L5, cathepsin L1g and cathepsin B) were expressed in yeast from cDNA clones isolated from adult, metacercariae and newly excysted juvenile flukes respectively. Each was used singly or in combination to vaccinate rats that were subsequently challenged with Fasciola hepatica metercercariae. Each protein induced an immune response, and all groups vaccinated with recombinant protein yielded significantly fewer and smaller flukes than the control group. Maximal protection of 83% was seen in the group vaccinated with cathepsin B and cathepsin L5 in combination.
Improving animal and human health through understanding liver fluke immunology
- Authors: Piedrafita, David , Spithill, Terry , Smith, Rebecca , Raadsma, Herman
- Date: 2010
- Type: Text , Journal article
- Relation: Parasite Immunology Vol. 32, no. 8 (2010), p. 572-581
- Full Text: false
- Reviewed:
- Description: Sheep, goats and cattle represent the most numerous and economically important agricultural species worldwide used as sources for milk, fibre and red meat. In addition, in the developing world, these species often represent the sole asset base for small-holder livestock farmers and cattle/buffaloes often provide the majority of draught power for crop production. Production losses caused by helminth diseases of these animals are a major factor in extending the cycle of poverty in developing countries and a major food security issue for developed economies. Fasciola spp. are one of the most important zoonotic diseases with a global economic impact in livestock production systems and a poorly defined but direct effect on human health. Improvements in human and animal health will require a concerted research effort into the development of new accurate and simple diagnostic tests and increased vaccine and drug development against Fasciola infections. Here, the use of definitive natural host breeds with contrasting resistance to Fasciola infections is discussed as a resource to contrast parasite–host interactions and identify parasite immune evasion strategies. Such studies are likely to boost the discovery of new vaccine, drug and diagnostic candidates and provide the foundation for future genetic selection of resistant animals.
Dual oxidase 2 and glutathione peroxidase gene expression are elevated in hyperimmunized sheep challenged with Haemonchus contortus
- Authors: Lees, Michael , Robinson, Nicholas , Ingham, Aaron , Kotze, A. , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 179, no. 1-3 (2011), p. 113-122
- Full Text: false
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- Description: A sequential biopsy sampling method was used to investigate oxidant and antioxidant gene responses in resistant sheep challenged with Haemonchus contortus larvae or a sham saline challenge. The expression of key sheep oxidant and antioxidant producing genes were measured in sequential samples removed from the abomasums at days 0, 1, 2, 3, 5, 7 and 28 post challenge. Gene expression levels at each time point were compared to expression at day 0, and levels of the various genes were also correlated to other markers of infection including immune cell counts and cytokine gene expression. The early response to larval challenge infection in resistant animals was marked by a divergence of two groups of host oxidant producing genes: the dual oxidase group (DUOX2/DUOXA2) showing increases in expression to day 7, while members of the phagocytic NADPH oxidase (PHOX) group showed significant decreases in expression. The change in DUOX2 expression between days zero and seven, when host resistance to infection is mediated, was negatively correlated to final worm burden suggesting NADPH oxidase expression may play a role in parasite expulsion. Expression of the DUOX group oxidants was positively correlated to expression of the Th2 cytokine IL4. Changes in host antioxidant pathways between different members of the glutathione peroxidase family (intestinal and plasma GPX) and genes involved in glutathione metabolism were also observed. This first study of the putative roles of oxidant production by the dual oxidase group, antioxidant glutathione pathways, immune cell populations, and cytokine profiles, in the development of resistance to infection by hyperimmune sheep are discussed.
A major cathepsin B protease from the liver fluke Fasciola hepatica has atypical active site features and a potential role in the digestive tract of newly excysted juvenile parasites
- Authors: Beckham, Simone , Piedrafita, David , Phillips, Carolyn , Samarawickrema, Nirma , Law, Ruby , Smooker, Peter , Quinsey, Noelene , Irving, James , Greenwood, Deanne , Verhelst, Steven , Bogyo, Matthew , Turk, Boris , Coetzer, Theresa , Wijeyewickrema, Lakshmi , Spithill, Terry , Pike, Robert
- Date: 2009
- Type: Text , Journal article
- Relation: International Journal of Biochemistry and Cell Biology Vol. 41, no. 7 (2009), p. 1601-1612
- Full Text: false
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- Description: The newly excysted juvenile (NEJ) stage of the Fasciola hepatica lifecycle occurs just prior to invasion into the wall of the gut of the host, rendering it an important target for drug development. The cathepsin B enzymes from NEJ flukes have recently been demonstrated to be crucial to invasion and migration by the parasite. Here we characterize one of the cathepsin B enzymes (recombinant FhcatB1) from NEJ flukes. FhcatB1 has biochemical properties distinct from mammalian cathepsin B enzymes, with an atypical preference for Ile over Leu or Arg residues at the P2 substrate position and an inability to act as an exopeptidase. FhcatB1 was active across a broad pH range (optimal activity at pH 5.5–7.0) and resistant to inhibition by cystatin family inhibitors from sheep and humans, suggesting that this enzyme would be able to function in extracellular environments in its mammalian hosts. It appears, however, that the FhcatB1 protease functions largely as a digestive enzyme in the gut of the parasite, due to the localization of a specific, fluorescently labeled inhibitor with an Ile at the P2 position. Molecular modelling and dynamics were used to predict the basis for the unusual substrate specificity: a P2 Ile residue positions the substrate optimally for interaction with catalytic residues of the enzyme, and the enzyme lacks an occluding loop His residue crucial for exopeptidase activity. The unique features of the enzyme, particularly with regard to its specificity and likely importance to a vital stage of the parasite's life cycle, make it an excellent target for therapeutic inhibitors or vaccination.
Field vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, Haemonchus contortus, confers significant protection against an experimental challenge infection
- Authors: Piedrafita, David , De Veer, Michael , Lydall, Jayne , Kraska, Troy , Elhay, Martin , Meeusen, Els
- Date: 2012
- Type: Text , Journal article
- Relation: Vaccine Vol. 30, no. 50 (2012), p. 7199-7204
- Full Text: false
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- Description: The availability of effective vaccines would add a valuable tool to the management of gastrointestinal nematode infections in livestock. While some experimental vaccines have shown protection in laboratory trials, few have been tested in the field. In the present study, eight month old sheep kept on pasture were treated with anthelmintic 8 weeks before vaccination with a larval surface antigen of the nematode parasite, Haemonchus contortus, under a commercially acceptable protocol, i.e. 2 immunizations using a commercial adjuvant; they were then given a controlled challenge infection 4 weeks later in indoor pens. Vaccination of sheep with 4 increasing doses of antigen resulted in significant reductions of 61% and 27% in cumulative faecal egg counts in the two highest dose groups, and a 69% reduction in worm burden in the highest dose group. Blood loss, as determined by packed cell volume, was also significantly reduced in the highest dose group of sheep. One outlier sheep showed an unusual increase in egg count without a concomitant increase in worm burden compared to the control sheep, indicating a vaccine-induced stress response. Antigen-specific serum antibody levels steadily increased in sheep while on pasture and decreased when transported to indoor pens. No difference in antibody levels could be detected between vaccinated and unvaccinated sheep, but all showed increased antibody levels compared to uninfected control sheep kept in indoors pens for 2–3 months, suggesting sheep were sensitized to the larval antigen either from low dose pasture contamination or cross reaction with pasture-related antigens. The results of these studies confirm the protective properties of the larval surface antigen and its protective effect when vaccinations are performed in the field.
Innate and adaptive resistance of Indonesian Thin Tail sheep to liver fluke: A comparative analysis of Fasciola gigantica and Fasciola hepatica infection
- Authors: Pleasance, Jill , Raadsma, Herman , Estuningsih, S. , Widjajanti, Sri , Meeusen, Els , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 178, no. 3-4 (2011), p. 264-272
- Full Text: false
- Reviewed:
- Description: In the current study, three independent trials directly compared Fasciola gigantica and Fasciola hepatica infection of ITT sheep. In all trials, F. hepatica infection resulted in higher worm burden recoveries and greater physiological damage to ITT sheep. Developmental differences of the two Fasciola species were also observed during the first twelve weeks of a primary infection, where the migration and growth of F. hepatica was more rapid than F. gigantica. Various immunological blood parameters were measured and indicated similar kinetics in the humoral and cellular responses during the time course of infection with each Fasciola species. In contrast to F. hepatica infection, we demonstrate an innate and adaptive comparative ability of ITT sheep to resist the early stages of infection with F. gigantica infection. Unraveling the mechanisms leading to this differential resistance may potentially lead to new methods for the control of fasciolosis and other human liver flukes.
Novel immunomic technologies for schistosome vaccine development
- Authors: McWilliam, Hamish , Driguez, Patrick , Piedrafita, David , McManus, Donald , Meeusen, Els
- Date: 2012
- Type: Text , Journal article
- Relation: Parasite Immunology Vol. 34, no. 5 (2012), p. 276-284
- Full Text: false
- Reviewed:
- Description: Schistosomiasis remains one of the most common human helminthiases, despite the availability of an effective drug against the causative parasites. Drug treatment programmes have several limitations, and it is likely that a vaccine is required for effective control. While decades of vaccine development have seen the discovery and testing of several candidate antigens, none have shown consistent and acceptable high levels of protection. The migrating larval stages are susceptible to immunity, however few larval-specific antigens have been discovered. Therefore, there is a need to identify novel larval-specific antigens, which may prove to be more efficacious than existing targets. Immunomics, a relatively new field developed to cope with the recent large influx of biological information, holds promise for the discovery of vaccine targets, and this review highlights some immunomic approaches to schistosome vaccine development. Firstly, a method to focus on the immune response elicited by the important and vulnerable larval stage is described, which allows a targeted study of the immunome at different tissue sites. Then, two high-throughput arrays are discussed for the identification of protein and carbohydrate antigens. It is anticipated that these approaches will progress vaccine development against the schistosomes, as well as other parasites.
The developing schistosome worms elicit distinct immune responses in different tissue regions
- Authors: McWilliam, Hamish , Driguez, Patrick , Piedrafita, David , Maupin, Kevin , Haab, Brian , McManus, Donald , Meeusen, Els
- Date: 2013
- Type: Text , Journal article
- Relation: Immunology and Cell Biology Vol. 91, no. 7 (2013), p. 477-485
- Full Text: false
- Reviewed:
- Description: Schistosome parasites follow a complex migration path through various tissues, changing their antigenic profile as they develop. A thorough understanding of the antibody response in each tissue region could help unravel the complex immunology of these developing parasites and aid vaccine design. Here we used a novel strategy for analysing the local antibody responses induced by Schistosoma japonicum infection at each site of infection. Cells from rat lymph nodes draining the sites of larval migration (the skin and lungs), the liver-lymph nodes where adults reside and the spleens were cultured to allow the in vivo-induced antibody-secreting cells to release antibody into the media. The amount and isotype of antibodies secreted in the supernatants differed significantly in the different lymph nodes and spleen, corresponding with the migration path of the schistosome worms. In addition, there were significant differences in binding specificity, as determined by surface labelling, western blots and by screening a glycan array. Through capturing the local antibody response, this study has revealed dramatic differences in the quality and specificity of the immune response at different tissue sites, and highlighted the existence of stage-specific protein and carbohydrate antigens. This will provide a valuable tool for the isolation of novel vaccine targets against the larval stages of schistosomes.
Galectin secretion and binding to adult Fasciola hepatica during chronic liver fluke infection of sheep
- Authors: Young, Anna , Barcham, Garry , McWilliam, Hamish , Piedrafita, David , Meeusen, Els
- Date: 2012
- Type: Text , Journal article
- Relation: Veterinary Immunology and Immunopathology Vol. 145, no. 1-2 (2012), p. 362-367
- Full Text: false
- Reviewed:
- Description: Galectins are increasingly recognised as important mediators of immune homeostasis and disease regulation, but comparatively little is known about their role in parasite infection. This study investigates the interaction between two ovine galectins, galectin-11 and galectin-14, and the parasitic liver fluke, F. hepatica. Galectin-14 was found in eosinophils infiltrating the tissue surrounding infected bile ducts and secreted in the connective tissue, while galectin-11 was specifically induced in epithelial cells of bile ducts from infected sheep. Strong nuclear staining was observed for galectin-11. Both galectins were found to be secreted into the bile fluid of parasite infected sheep, and were also detected in the excretory/secretory products of adult flukes, following their removal from the ovine host. Recombinant galectin-14, but not recombinant galectin-11, was found to bind specifically to the surface tegument of adult flukes in a carbohydrate dependent manner. This study shows for the first time that both galectin-14 and galectin-11 are produced in liver tissue after chronic liver fluke infection and that they can directly interact with the parasite in the bile ducts. Galectin-11 may also be involved in epithelial cell turnover and cancerogenesis.
The kinetics of local cytokine and galectin expression after challenge infection with the gastrointestinal nematode, Haemonchus contortus
- Authors: Robinson, Nicholas , Pleasance, Jill , Piedrafita, David , Meeusen, Els
- Date: 2011
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 41, no. 5 (2011 2011), p. 487-493
- Full Text: false
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- Description: Gastrointestinal nematode parasites undergo several developmental stages within their mammalian host, each presenting different antigenic challenges to the immune system. To examine the expression of different immune mediators over time, biopsy samples were collected from the cannulated abomasum (true stomach) of immune sheep at several times after a challenge infection with Haemonchus contortus L3s. IL-5 and IL-13 mRNA expression levels were significantly increased above saline-challenged control levels at 5 and 7 days post challenge, while IL-4 showed an earlier peak at day 2 post challenge. IL-5, IL-13 and IL-4, as well as IFN-
The relationship between the rapid rejection of Haemonchus contortus larvae with cells and mediators in abomasal tissues in immune sheep
- Authors: Kemp, Joanna , Robinson, Nicholas , Meeusen, Els , Piedrafita, David
- Date: 2009
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 39, no. 14 (2009), p. 1589-1594
- Full Text: false
- Reviewed:
- Description: Rapid rejection or immune exclusion of challenge larvae is a well recognised phenomenon in sheep hypersensitised by repeated infection with gastrointestinal nematodes. While mast cells and globule leukocytes (GLs) are typically associated with this rapid rejection response, the exact mechanisms and mediators involved are not known. This study has adapted a recently developed ex vivo tissue explant model to examine in more detail the cells and mediators involved in preventing establishment of Haemonchus contortus L3s in abomasal tissue of sensitised sheep. Hypersensitisation of sheep by repeated larval infection resulted in a significant inhibition of larval establishment in abomasal tissue cultures and the extent of inhibition was dependent on the sensitisation dose. Both mast cells and GLs, but not eosinophils, were increased in abomasal tissues of hypersensitised sheep. Globule leucocyte numbers decreased significantly after 3 h of culture, independent of the addition of L3s. In contrast, mast cell numbers only decreased after addition of L3s to the tissue cultures and this was associated with an increased release of histamine in tissue washes after incubation with L3s. Although, there was no significant difference in the number of tissue eosinophils between the groups, there was a marked increase in the eosinophil-specific protein, galectin-14, in tissue washes of the hypersensitised sheep after culture, suggesting eosinophils and their products may play a hitherto unrecognised role in the rapid rejection response. Further studies using specific inhibitors in this ex vivo tissue explant model may delineate the relative role of each cell population and mediator in the rapid rejection process.
Host responses during experimental infection with Fasciola gigantica and Fasciola hepatica in Merino sheep II. Development of a predictive index for Fasciola gigantica worm burden
- Authors: Raadsma, Herman , Kingsford, Nicola , Suharyanta, S. , Spithill, Terry , Piedrafita, David
- Date: 2008
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 154, no. 3-4 (2008), p. 250-261
- Full Text: false
- Reviewed:
- Description: This study reports on the predictive relationship between serological, immunological and pathological responses following experimental inoculation with incremental doses of Fasciola gigantica in sheep. Fifty, 6-month-old, naive Merino wethers were allocated to one of 5 experimental groups, four of which received 50, 125, 225 and 400 metacercariae, respectively, whilst a 5th group acted as non-inoculated control. Strong individual correlations were observed between liver score, GLDH (glutamate dehydrogenase), GGT (gamma glutamyl transferase), CatL5 (cathepsin L5) antibody titre (IgG1, IgA), eosinophilia, and the total worm count or worm biomass. A combination of multiple indicator traits performed significantly better than any single indicator trait alone. The best predictive index accounted for up to 88% of observed worm burden (Wb) if information on inoculation dose was available. Without knowledge of inoculation dose, such as under field conditions, up to 67% of variation in worm burden could be predicted. In contrast, the best single predictor variable (liver damage score) accounted for up to 50% of worm burden, and in the absence of post-slaughter information, serum levels of anti-cathepsin IgA antibody titres accounted for 35% of predicted variation in worm burden. The utility of a predictive index under both field and experimental inoculation conditions is discussed.
Overcoming liver fluke as a constraint to ruminant production in South-East Asia
- Authors: Raadsma, Herman , Fullard, K. , Kingsford, Nicola , Margawati, Endang , Estuningsih, S. , Widjajanti, Sri , Subandriyo, N , Spithill, Terry , Piedrafita, David
- Date: 2008
- Type: Text , Book
- Full Text: false
- Reviewed:
Comparative experimental Haemonchus contortus infection of two sheep breeds native to the Canary Islands
- Authors: Gonzalez, Jorge , Hernandez, Alvaro , Molina, Jose , Fernandez, Antonio , Raadsma, Herman , Meeusen, Els , Piedrafita, David
- Date: 2008
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 153, no. 304 (2008), p. 374-378
- Full Text: false
- Reviewed:
- Description: This study compares the susceptibility to Haemonchus contortus infection in two breeds of sheep endemic to the Canary Islands, the Canaria Hair Breed sheep and the Canaria sheep. Sheep were experimentally infected with 20,000 larvae of H. contortus and animals killed on days 7 and 28 post-infection. No difference between sheep breeds were detected in immature worm counts at days 7 or 28 post-infection. However, in comparison to the Canaria sheep breed, the Canaria Hair Breed sheep showed lower mean faecal egg counts, lower adult worm counts, lower number of eggs in utero and female worm stunting. Overall, these data suggest that the Canaria Hair Breed sheep has a greater resistance to H. contortus infection than Canaria sheep, and that this resistance may act at the level of the adult parasite.
Resistance to liver fluke infection in the natural sheep host is correlated with a type-1 cytokine response
- Authors: Pleasance, Jill , Wiedosari, E. , Raadsma, Herman , Meeusen, Els , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Parasite Immunology Vol. 33, no. 9 (2011), p. 495-505
- Full Text: false
- Reviewed:
- Description: Indonesian thin-tail (ITT) sheep can resist infection with Fasciola gigantica but not F. hepatica and presents an ideal model to investigate the mechanisms of liver fluke resistance in a natural host. This study examines the local and systemic immune responses of sheep during Fasciola infection and demonstrates that different anatomical tissues display distinct cytokine profiles consistent with liver fluke migration. The study also reveals a significant difference in the cytokine and antibody profiles of ITT sheep infected with F. gigantica compared with F. hepatica, with a higher ratio of IL-4/IFN-
Molecular cloning and characterisation of ovine dual oxidase 2
- Authors: Lees, Michael , Nagaraj, Shivashankar , Piedrafita, David , Kotze, A. , Ingham, Aaron
- Date: 2012
- Type: Text , Journal article
- Relation: Gene Vol. 500, no. 1 (2012), p. 40-46
- Full Text: false
- Reviewed:
- Description: The dual oxidases (DUOX1 and DUOX2) are NADPH-dependant hydrogen peroxide-producing enzymes that are reported to function in a physiological capacity and as a component of the mucosal immune response. We have previously reported increased expression of the DUOX2 gene in the gut mucosa of sheep in response to gastrointestinal nematode (GIN) challenge. In this paper, we report the cloning of the full-length ovine DUOX2 transcript, using a PCR based strategy. The ovine DUOX2 transcript includes an ORF of 4644 bases, and encodes a protein with 97% identity to the bovine sequence. We also cloned a fragment of DUOX1 (encompassing nucleotides 2692–2829), and the proximal promoter sequence of DUOX2. Through analysis of sequence data we have confirmed that DUOX1 and DUOX2 are co-located in a head to tail arrangement conserved across many species. Alignment of the sequences to the ovine genome predicts a location of this gene cluster on ovine chromosome 7. We quantified the expression of ovine DUOX1 and DUOX2 transcripts in 24 different sheep tissues, and discovered tissue specific expression signatures. DUOX2 was found to be most highly expressed in tissues of the gastrointestinal tract, while expression of DUOX1 predominated in the bladder. Rapid amplification of cDNA ends (RACE) analysis identified the existence of multiple 5′ UTR variants in DUOX2, ranging in size from 32 to 242 nucleotides, with 3 distinct transcribed regions. Real time PCR quantification of the DUOX2 UTR variants revealed that these were differentially expressed between tissues, and at various stages of the response to GIN parasite infection. The collective evidence suggested a complex regulation of DUOX2, prompting a bioinformatic analysis of the proximal promoter regions of ovine DUOX2 to identify potential transcription factor binding sites (TFBS) that may explain the differences in the observed expression of the transcript variants of DUOX2. Possible transcription factor families that may regulate this process were identified as Kruppel-like factors (KLF), ETS-factors, erythroid growth receptor factors (EGRF) and myogenic differentiation factors (MYOD)
Increased production through parasite control : can ancient breeds of sheep teach us new lessons?
- Authors: Piedrafita, David , Raadsma, Herman , Gonzalez, Jorge , Meeusen, Els
- Date: 2010
- Type: Text , Journal article
- Relation: Trends in Parasitology Vol. 26, no. 12 (2010), p. 568-573
- Full Text: false
- Reviewed:
- Description: With a rising world population and economic development, the global demand for meat, milk and other animal products is increasing dramatically. Controlling parasitic diseases in livestock, in particular helminth infections, could rapidly improve productivity and resource utilization. There is a growing interest in indigenous ruminant breeds because these animals have adapted to survive with minimal maintenance in the presence of high exposure to parasite infection. Recent findings on the mechanisms of parasite resistance in indigenous breeds are discussed, and the possibility that such studies may lead to new insight into the immunity and control of parasites proposed. These findings have important implications for the preservation of poorly characterized local indigenous breeds.