Conference Agenda

Extensive studies on model organisms like Caenorhabditis elegans (elegant worm) and Drosophila melanogaster (vinegar fly) have significantly enhanced our understanding of complex biological mechanisms in multicellular organisms. By leveraging comprehensive datasets derived from genomics, transcriptomics, and proteomics, scientists have identified essential genes, crucial for life. Recent investigations have explored the possibility of predicting essential genes using advanced bioinformatics, particularly employing machine learning techniques to extract features from DNA, RNA, protein, and cellular data. This approach shows promise for predicting essential genes within and across related species, such as those within the same evolutionary clade or phylum. In the present study, we have applied this method to predict essential genes within the phylum Nematoda (clade V), focusing on the pathogenic parasitic nematode H. contortus. By cross-predicting essential genes between C. elegans and H. contortus, we prioritized potential drug targets encoded by these genes. The analysis highlighted essential genes primarily involved in critical biological processes like ribosome biogenesis, translation, RNA processing, and signaling, with high transcription levels in specific cell types. These findings suggest that this computational approach holds promise for identifying and prioritizing drug target candidates in parasitic nematodes for further experimental validation.

Haemonchosis is a disease caused by the haematophagous barber’s pole worm, Haemonchus contortus, which affects livestock animals worldwide. Despite the major significance of this parasite worldwide and its widespread resistance to current treatments, the lack of a high-quality genome for the well-defined strain of this parasite from Australia, called Haecon-5, has constrained research in a number of areas, including host-parasite interactions, drug discovery and population genetics. To enable research in these areas, we report here a chromosome-contiguous genome (~280 Mb) for Haecon-5 with high-quality models for 19,234 protein-coding genes. Comparative genomic analyses show significant genomic similarity (synteny) with a UK strain of H. contortus, called MHco3(ISE).N1 (abbreviated as “ISE”), but we also discover marked differences in genomic structure/gene arrangements, distribution of nucleotide variability (SNPs and indels) and orthology between Haecon-5 and ISE. We used the genome and extensive transcriptomic resources for Haecon-5 to predict a subset of essential single-copy genes employing a “cross-species” machine learning approach and prioritised ten of them for further characterisation. The present Haecon-5 reference genome and associated resources now underpin a broad range of fundamental investigations of H. contortus and could assist in accelerating the discovery of novel intervention targets to combat haemonchosis.

Pituitary Pars Intermedia Dysfunction (PPID) is a detrimental endocrinopathy affecting 20-25% of geriatric horses. Formation of hyperplastic tissue in the pars intermedia leads to increased hormone secretion, resulting in symptoms such as hypertrichosis, lethargy, weight loss and increased susceptibility to infections including parasitic nematodes. The immune mechanisms underlying increased infection susceptibility is largely unknown.

This research investigated the function of Peripheral Blood Mononuclear Cells (PBMC) in PPID (n-6) and non-PPID (n=6) horses exposed to a natural infection of strongyles. PBMC were stimulated in vitro with lipopolysaccharide (LPS), concanavalin A (ConA), phorbol myristate acetate (PMA) and a small strongyle antigen (GALA-cat) for 48h. Following stimulation, cell proliferation and the presence of IgG(T) antibodies were measured.

The results showed increased cell proliferation in PPID horses following stimulation with LPS (p < 0.001), ConA (p = 0.014), PMA (p = 0.045) and GALA-cat (p = 0.017). However, there were no significant differences in the concentration of total IgG(T) antibodies in the supernatant, except for the PPID horses having lower IgG(T) levels in unstimulated conditions. These results suggest that the PBMC of PPID horses can proliferate, however the rates of the proliferation are increased and IgG(T) production is reduced in unstimulated conditions.

This study assessed gastrointestinal (GI) parasite control practices used by Australian dairy goat farmers through an online questionnaire survey. The questionnaire consisted of 54 questions on farm demographics, husbandry and grazing management, knowledge of GI parasites and their significance, diagnosis, anthelmintics, and alternative control options. After a pilot survey, the questionnaire link was sent to all registered members (n = 456) of the Dairy Goat Society of Australia Ltd on 17^th April 2023. The response rate was 14% (66/456). Most respondents owned medium-sized herds (20-100 goats; 56%, 37/66) followed by small (<20 goats; 36%) and large (>100 goats; 8%) herds. Seventy-four percent (49/66) of respondents observed parasite-related illnesses in their goats and two-thirds assessed worm burden using faecal egg counts. Most respondents (97%; 183/188) perceived that GI parasites caused production losses or health impacts and ranked Haemonchus contortus as the most significant parasite. Ninety-four percent (62/66) of respondents used anthelmintics, primarily a commercial combination of four anthelmintics (levamisole, closantel, albendazole, and abamectin), benzimidazoles and macrocyclic lactones. Although targeted deworming was the most common method of controlling GI parasites, most respondents were unaware of anthelmintic resistance. These findings will pave the way to devise guidelines for GI parasite control in goats.

East Coast fever (ECF), caused by the protozoan Theileria parva, and sheep flystrike, caused by the parasitic Lucilia cuprina, pose significant challenges to livestock health in sub-Saharan Africa and tropical regions. Current control methods for ECF rely on a live-parasite vaccine, which has practical limitations associated with it. Control methods for sheep blowfly primarily involve mulesing and use of insecticides, which has increased insect resistance. Our research focuses on developing more sustainable and effective control strategies against livestock parasites like ECF and sheep blowfly by combining molecular biology with nanotechnology. The published ECF study has shown co-immunization of cattle (Bos taurus) with two nanotechnologies along with p67C antigen resulted in stimulation of both high Ab titers and CD4 T cell responses. Our work is also investigating the innovative RNA interference (RNAi) technology in combination material science to target specific genes in sheep blowflies, to develop biological control to benefit animal health and productivity.

Reference: Lacasta A, Mody KT, De Goeyse I, Yu C, Zhang J, Nyagwange J, et al. Synergistic Effect of Two Nanotechnologies Enhances the Protective Capacity of the Theileria parva Sporozoite p67C Antigen in Cattle. J Immunol. 2021;206(4):686-99. Epub 2021/01/10. doi:10.4049/jimmunol.2000442.

Despite being logical targets, surface tegument proteins of juvenile Fasciola hepatica have not been studied as vaccines to control fasciolosis in cattle. Nine recombinant F. hepatica tegument proteins (Tetraspanins (TSP) 2 and 3; Annexins (Anx) 2, 3 and 8;Tegument proteins FhTeg1, 5, 22 and 25), as well the immunomodulator Transforming Growth Factor Beta (TGF-β)-like homologue FhTLM, were tested as vaccines, both alone or as combinations. TSP2 was also evaluated fused to the E. coli heat-labile entero-toxin B subunit LTB adjuvant using intranasal vaccination. Five antigens were assessed in combination with Glutathione S-transferase (GST).

Female Angus/Angus-cross cattle (n=6-7) were vaccinated 2 or 3 times with proteins formulated in Freund’s adjuvant or a nanoparticle adjuvant and challenged with metacercariae. Significant reductions in mean fluke numbers (38-48%) were observed in 4 groups using combinations of TSP3, Anx2, Anx3 or Anx8, as well as with FhTLM/GST. However, there was variation between trials in vaccine efficacy. Efficacy was associated (r² = 0.915) with the fraction of animals in each group showing fluke counts less than the lowest value in control groups. The data suggest that, under our experimental conditions, 90-100% of animals show relatively low fluke counts with a vaccine efficacy of only 43-48%.