Veterinary Biosciences - Research Publications
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ItemThermal proteome profiling reveals Haemonchus orphan protein HCO_011565 as a target of the nematocidal small molecule UMW-868(FRONTIERS MEDIA SA, 2022-10-14)Parasitic roundworms (nematodes) cause destructive diseases, and immense suffering in humans and other animals around the world. The control of these parasites relies heavily on anthelmintic therapy, but treatment failures and resistance to these drugs are widespread. As efforts to develop vaccines against parasitic nematodes have been largely unsuccessful, there is an increased focus on discovering new anthelmintic entities to combat drug resistant worms. Here, we employed thermal proteome profiling (TPP) to explore hit pharmacology and to support optimisation of a hit compound (UMW-868), identified in a high-throughput whole-worm, phenotypic screen. Using advanced structural prediction and docking tools, we inferred an entirely novel, parasite-specific target (HCO_011565) of this anthelmintic small molecule in the highly pathogenic, blood-feeding barber's pole worm, and in other socioeconomically important parasitic nematodes. The "hit-to-target" workflow constructed here provides a unique prospect of accelerating the simultaneous discovery of novel anthelmintics and associated parasite-specific targets.
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ItemNo Preview AvailableChromosome-level genome of Schistosoma haematobium underpins genome-wide explorations of molecular variation(PUBLIC LIBRARY SCIENCE, 2022-02)Urogenital schistosomiasis is caused by the blood fluke Schistosoma haematobium and is one of the most neglected tropical diseases worldwide, afflicting > 100 million people. It is characterised by granulomata, fibrosis and calcification in urogenital tissues, and can lead to increased susceptibility to HIV/AIDS and squamous cell carcinoma of the bladder. To complement available treatment programs and break the transmission of disease, sound knowledge and understanding of the biology and ecology of S. haematobium is required. Hybridisation/introgression events and molecular variation among members of the S. haematobium-group might effect important biological and/or disease traits as well as the morbidity of disease and the effectiveness of control programs including mass drug administration. Here we report the first chromosome-contiguous genome for a well-defined laboratory line of this blood fluke. An exploration of this genome using transcriptomic data for all key developmental stages allowed us to refine gene models (including non-coding elements) and annotations, discover 'new' genes and transcription profiles for these stages, likely linked to development and/or pathogenesis. Molecular variation within S. haematobium among some geographical locations in Africa revealed unique genomic 'signatures' that matched species other than S. haematobium, indicating the occurrence of introgression events. The present reference genome (designated Shae.V3) and the findings from this study solidly underpin future functional genomic and molecular investigations of S. haematobium and accelerate systematic, large-scale population genomics investigations, with a focus on improved and sustained control of urogenital schistosomiasis.
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Item"Escalibur"-A practical pipeline for the de novo analysis of nucleotide variation in nonmodel eukaryotes(WILEY, 2022-07)The revolution in genomics has enabled large-scale population genetic investigations of a wide range of organisms, but there has been a relatively limited focus on improving analytical pipelines. To efficiently analyse large data sets, highly integrated and automated software pipelines, which are easy to use, efficient, reliable, reproducible and run in multiple computational environments, are required. A number of software workflows have been developed to handle and process such data sets for population genetic analyses, but effective, specialized pipelines for genetic and statistical analyses of nonmodel organisms are lacking. For most species, resources for variomes (sets of genetic variations found in populations of species) are not available, and/or genome assemblies are often incomplete and fragmented, complicating the selection of the most suitable reference genome when multiple assemblies are available. Additionally, the biological samples used often contain extraneous DNA from sources other than the species under investigation (e.g., microbial contamination), which needs to be removed prior to genetic analyses. For these reasons, we established a new pipeline, called Escalibur, which includes: functionalities, such as data trimming and mapping; selection of a suitable reference genome; removal of contaminating read data; recalibration of base calls; and variant-calling. Escalibur uses a proven gatk variant caller and workflow description language (WDL), and is, therefore, a highly efficient and scalable pipeline for the genome-wide identification of nucleotide variation in eukaryotes. This pipeline is available at https://gitlab.unimelb.edu.au/bioscience/escalibur (version 0.3-beta) and is essentially applicable to any prokaryote or eukaryote.
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ItemChromosome-scale Echinococcus granulosus (genotype G1) genome reveals the Eg95 gene family and conservation of the EG95-vaccine molecule(NATURE PORTFOLIO, 2022-03-03)Cystic echinococcosis is a socioeconomically important parasitic disease caused by the larval stage of the canid tapeworm Echinococcus granulosus, afflicting millions of humans and animals worldwide. The development of a vaccine (called EG95) has been the most notable translational advance in the fight against this disease in animals. However, almost nothing is known about the genomic organisation/location of the family of genes encoding EG95 and related molecules, the extent of their conservation or their functions. The lack of a complete reference genome for E. granulosus genotype G1 has been a major obstacle to addressing these areas. Here, we assembled a chromosomal-scale genome for this genotype by scaffolding to a high quality genome for the congener E. multilocularis, localised Eg95 gene family members in this genome, and evaluated the conservation of the EG95 vaccine molecule. These results have marked implications for future explorations of aspects such as developmentally-regulated gene transcription/expression (using replicate samples) for all E. granulosus stages; structural and functional roles of non-coding genome regions; molecular 'cross-talk' between oncosphere and the immune system; and defining the precise function(s) of EG95. Applied aspects should include developing improved tools for the diagnosis and chemotherapy of cystic echinococcosis of humans.
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ItemNo Preview AvailableHigh-quality reference genome for Clonorchis sinensis(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2021-05)The Chinese liver fluke, Clonorchis sinensis, causes the disease clonorchiasis, affecting ~35 million people in regions of China, Vietnam, Korea and the Russian Far East. Chronic clonorchiasis causes cholangitis and can induce a malignant cancer, called cholangiocarcinoma, in the biliary system. Control in endemic regions is challenging, and often relies largely on chemotherapy with one anthelmintic, called praziquantel. Routine treatment carries a significant risk of inducing resistance to this anthelmintic in the fluke, such that the discovery of new interventions is considered important. It is hoped that the use of molecular technologies will assist this endeavour by enabling the identification of drug or vaccine targets involved in crucial biological processes and/or pathways in the parasite. Although draft genomes of C. sinensis have been published, their assemblies are fragmented. In the present study, we tackle this genome fragmentation issue by utilising, in an integrated way, advanced (second- and third-generation) DNA sequencing and informatic approaches to build a high-quality reference genome for C. sinensis, with chromosome-level contiguity and curated gene models. This substantially-enhanced genome provides a resource that could accelerate fundamental and applied molecular investigations of C. sinensis, clonorchiasis and/or cholangiocarcinoma, and assist in the discovery of new interventions against what is a highly significant, but neglected disease-complex.
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ItemNanopore Sequencing Resolves Elusive Long Tandem-Repeat Regions in Mitochondrial Genomes(MDPI, 2021-02)Long non-coding, tandem-repetitive regions in mitochondrial (mt) genomes of many metazoans have been notoriously difficult to characterise accurately using conventional sequencing methods. Here, we show how the use of a third-generation (long-read) sequencing and informatic approach can overcome this problem. We employed Oxford Nanopore technology to sequence genomic DNAs from a pool of adult worms of the carcinogenic parasite, Schistosoma haematobium, and used an informatic workflow to define the complete mt non-coding region(s). Using long-read data of high coverage, we defined six dominant mt genomes of 33.4 kb to 22.6 kb. Although no variation was detected in the order or lengths of the protein-coding genes, there was marked length (18.5 kb to 7.6 kb) and structural variation in the non-coding region, raising questions about the evolution and function of what might be a control region that regulates mt transcription and/or replication. The discovery here of the largest tandem-repetitive, non-coding region (18.5 kb) in a metazoan organism also raises a question about the completeness of some of the mt genomes of animals reported to date, and stimulates further explorations using a Nanopore-informatic workflow.
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ItemExpanded complement of Niemann-Pick type C2-like protein genes in Clonorchis sinensis suggests functions beyond sterol binding and transport(BMC, 2020-01-23)BACKGROUND: The parasitic flatworm Clonorchis sinensis inhabits the biliary tree of humans and other piscivorous mammals. This parasite can survive and thrive in the bile duct, despite exposure to bile constituents and host immune attack. Although the precise biological mechanisms underlying this adaptation are unknown, previous work indicated that Niemann-pick type C2 (NPC2)-like sterol-binding proteins might be integral in the host-parasite interplay. Expansions of this family in some invertebrates, such as arthropods, have shown functional diversification, including novel forms of chemoreception. Thus, here we curated the NPC2-like protein gene complement in C. sinensis, and predicted their conserved and/or divergent functional roles. METHODS: We used an established comparative genomic-bioinformatic approach to curate NPC2-like proteins encoded in published genomes of Korean and Chinese isolates of C. sinensis. Protein sequence and structural homology, presence of conserved domains and phylogeny were used to group and functionally classify NPC2-like proteins. Furthermore, transcription levels of NPC2-like protein-encoding genes were explored in different developmental stages and tissues. RESULTS: Totals of 35 and 32 C. sinensis NPC2-like proteins were predicted to be encoded in the genomes of the Korean and Chinese isolates, respectively. Overall, these proteins had low sequence homology and high variability of sequence alignment coverage when compared with curated NPC2s. Most C. sinensis proteins were predicted to retain a conserved ML domain and a conserved fold conformation, with a large cavity within the protein. Only one protein sequence retained the conserved amino acid residues required in bovine NPC2 to bind cholesterol. Non-canonical C. sinensis NPC2-like protein-coding domains clustered into four distinct phylogenetic groups with members of a group frequently encoded on the same genome scaffolds. Interestingly, NPC2-like protein-encoding genes were predicted to be variably transcribed in different developmental stages and adult tissues, with most being transcribed in the metacercarial stage. CONCLUSIONS: The results of the present investigation confirms an expansion of NPC2-like proteins in C. sinensis, suggesting a diverse array of functions beyond sterol binding and transport. Functional explorations of this protein family should elucidate the mechanisms enabling the establishment and survival of C. sinensis and related flukes in the biliary systems of mammalian hosts.