3.2 Microbiology/Parasitology
3.2.1 PBV 251
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| Programme Goal: | To develop the technology to enable the possum parasite P. trichosuri to be used as a vector for genes expressing proteins which could interfere with reproductive success, growth or longevity of its host. |
Objective 1
| Objective Title: | Parastrongyloides trichosuri-specific gene promoters |
| Research Leader: | Dr Allen Gruenberg |
Description:
Promoter regions of genes are normally upstream of coding regions and are essential in initiating expression of gene products. In order to achieve genetic transformation of P. trichosuri using reporter genes which have successfully transformed the free-living nematode Caenorhabditis elegans, the researchers believe it may be necessary to modify plasmid constructs to incorporate specific P. trichosuri transcriptional promoters. A P. trichosuri genomic library will be screened for analogues of C. elegans promoter sequences already in use. Once isolated, the DNA sequences will be inserted into plasmid constructs incorporating reporter genes and then tested in P. trichosuri. Additional C. elegans promoters which initiate expression of proteins found at the nematode surface, will be isolated using polymerase chain reactions (PCR) and tested first in C. elegans and then in P. trichosuri.
Objective 2
| Objective Title: | Immunogenic protein characterization |
| Research Leader: | Dr David Heath |
Description:
A P. trichosuri specific 70-80Kd secreted protein produced by infective larvae during penetration of the host has been demonstrated to be immunogenic in infected possums. Characterizing the sequence of this protein provides an alternative approach to obtain a potentially useful promoter for use in expressing gene products in a P. trichosuri vector. A P. trichosuri cDNA library will be screened using specific antibodies and the upstream region containing the putative gene promoter will be identified from the genomic library and tested as described in Objective 1. This work forms part of a PhD research programme, being undertaken by Ms Jan Newton-Howes and funded by an AGMARDT PhD scholarship.
Objective 3
| Objective Title: | Pantropic retroviral vectors |
| Research Leader: | Dr Allen Gruenberg |
Description:
Worms transformed with foreign genes contained in plasmid vectors usually carry these genes as extra-chromosomal arrays which are not inherited in a Mendelian fashion. Various techniques are available in C. elegans to encourage extrachromosomal arrays to integrate into the worm genome but the rate of success is often low. While such techniques may also be successful in P. trichosuri, an alternative approach may be to use pantropic retroviral vectors to insert foreign sequences into the worm genome. Initially researchers will experiment with the use of these vectors in C. elegans and once techniques are established, expand the work to include P. trichosuri.
3.2.2 SRC607
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| Programme Goal: | To determine the nature of the infectious disease responsible for high death losses in captive brushtail possums at the Landcare Research animal research facility in Lincoln. |
Objective 1
| Objective Title: | Confirmation of viral etiology |
| Research Leader: | M L Wickstrom and J S O'Keefe |
Description:
Landcare Research and AgResearch have been conducting a collaborative investigation of a disease affecting newly captured brushtail possums at Landcare Research's Lincoln animal research facility. The disease is highly infectious, with morbidity rates approaching 100%, and mortality rates averaging 50% - 60%. Preliminary results of histopathologic, microbiologic, haematologic and virus agglutination studies indicate that the primary agent is probably an enteric virus. The disease is characterised by sudden onset of anorexia and depression of 1 to 3 days duration, which may be followed by variable degrees of diarrhoea, with consequent fluid loss and dehydration. The diarrhoeic phase persists for a few hours to 2-3 days, and is usually followed by death. A significant percentage of possums exhibit no signs of diarrhoea, but are simply found dead after a short period of anorexia and lethargy.
Efforts to isolate the organism are ongoing, but have not yet been successful. The proposed research would help to confirm the viral etiology of this disease, as well as define the incubation period and identify the probable mode of transmission.
| 3.2.3 | PBC 208 |
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| Programme Goal: | To induce fetal wastage and/or neonatal mortality in possums by blocking the transfer of maternal riboflavin to the fetus and/or newborn. |
Objective 1
| Objective Title: | RCP: Identification, purification and biological consequences. |
| Research Leader: | Dr Dominique Vanmontfort |
Description:
Plasma from non-pregnant, pregnant and early lactating possums will be screened for RCP activity. Plasma will be subjected to several protein purification techniques including ammonium sulphate recipitation, ion exchange chromatography and gel filtration chromatography. Detection of a putative RCP will be based on measuring mobility on PAGE, absorbency at 280 nm and at 450 nm and ability to bind to riboflavin. Sufficient RCP will be purified to homogeneity for partial amino acid sequence analysis so that primers can be designed for isolating RCP cDNA.
Contact for Enquiries
Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0623
Fax: +64 4 894 0741
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