Research

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Photograph of Dr DP MalatjiDr DP Malatji

Exploring the genetic resistance of livestock to nematode infection using RNA-Sequencing

Background

Parasitism is a serious global problem in livestock, and it causes severe constraints to health, welfare and production of livestock as severe cases can result in mortality. Gastrointestinal nematode infections are a major economic problem for farmers worldwide and ranks high among factors that contribute to substantial economic losses.

 Traditional nematode control

Traditional control of animal gastrointestinal nematode infections depends mainly on the use of anthelmintics, which are often expensive and even unavailable in low input production systems. Other disadvantages of using this control method is the residual effects of drugs remaining in meat which lead to serious animal welfare and food safety problems. Therefore, alternative control strategies that are less dependent on anthelmintics are required to be adopted.

 Alternate nematode control

Genetic control strategies are a viable option for controlling parasitism particularly for animals raised under low-input production systems. Understanding the host-parasite inter phase is a prerequisite to develop such control strategies. Resistance to parasites is a complex trait influenced by the genes of the host animal and the environment they find themselves in. There is a dearth of information available on the genetic resistance to gastrointestinal parasites in livestock in South Africa and most developing countries, which makes it difficult to select for resistance to parasites or implement effective control strategies. Therefore, in order to improve breeding animals that are resistance to diseases, it is important to examine the genetic background of an animal by identifying individual mutations and variants supporting pathways that differentiate health and disease.

Breeding for animals that are resistant to parasites and diseases is based on selecting genes and genotypes that have an ability to survive or cope with harsh conditions such as parasite infections and diseases. The advantages of breeding animals that are resistant to diseases include improved animal welfare, immunity, environmental adaptation to drugs and increase returns for breeders in terms of time and money.

Sequencing technologies

The availability of tools to understand host-pathogen interactions will allow significant progress in identifying and manipulating genetics for the improvement of resistance to gastrointestinal nematodes infections. Access to molecular and genomic approaches opens up opportunities to understand genetics, environmental and the host-pathogen interactions and can assist in the development of new control strategies. Whole genome and transcriptome sequencing technologies provide opportunities to investigate the genes that play a role in potential resistance to parasite in livestock populations distributed across the environmental gradient. In recent years the rapid advances in RNA-seq technologies, have resulted in more genomes sequenced faster and cheaper than ever before. This technology helps in characterizing host response to nematode infection and identify molecular mechanisms that underlie host resistance to gastrointestinal nematodes, and it provides much higher resolution measurements of gene expression at a comparable cost.

Prof James Oguttu

Applied Epidemiology and public health

Our research employs descriptive and analytic epidemiologic techniques to promote and protect the public’s health. The focus of our research is antimicrobial resistance, a problem of huge public health significance because of the potential it has to wipe out the gains made in the medical field since the discovery of antimicrobials. The development of antimicrobial resistance renders existing antimicrobials ineffective. In our research we investigate the burden and trends of antimicrobial resistance in humans and domestic animals, and also assess the possibility of antimicrobial resistance clustering in space. However, we also apply epidemiological techniques to investigate other problems of public health significance. For example we are currently conducting several projects that are looking at “Knowledge, Attitude and Practices” (KAP studies) towards phenomenon of public health importance.

Prof Khayalethu Ntushelo

Molecular basis of plant-microbes interactions and plant pathogen biology

The ever-increasing demand for food requires that crops are able to withstand disease pressure, utilize beneficial microbes to maximize productivity. Plant molecular mechanisms for disease resistance are an important subject of study so that basic knowledge for breeding and plant genetic modification can be generated. A multi-disciplinary approach which includes plant gene expression profiling, proteomics, metabolomics and high-resolution imaging is currently embarked upon to answer such questions as: What properties does a plant need to cope with disease pressure? What mechanisms are involved in plantmicrobe beneficial associations? This work utilizes high-end instruments and novel information is being generated to add to the body of knowledge.

Dr Ntanganedzeni Mapholi

Genetic architecture of cattle ticks and their associated tick-borne pathogens in South Africa

In Southern Africa, tick and tick-borne diseases are severe problems in livestock production. Estimated annual losses due to ticks and tick-borne diseases in South Africa is about R1 billion. It is reported that about 80% of the world’s cattle suffer to some extent from the deleterious effects caused by ticks. The efforts to eradicate ticks and tick-borne diseases using chemical control strategies have been implemented in South Africa, however, these chemicals are costly, cattle susceptibility to ticks remain unchanged, consumer concerns about chemical residues and resistance of tick species to chemicals still remain the major challenges. This has created rising demands for different approaches that can alleviate the negative effects of ticks on livestock industry and thereby enhance the livestock industries’ contribution to the world economy. Therefore, there is a considerable need to explore alternative technologies of tick control such as genomics. Our research is focused on the use of genomic approaches including high through put genotyping and sequencing to identify genes associated to host genetic resistance to ticks (HGRT). These approaches may provide tools that will allow us to develop sound tick control breeding programmes in cooperating HGRT to the South African livestock farming.

Prof Monde Ntwasa

The Sweet Tooth of Cancer and Anti-cancer Drug Discovery

Cancer is regarded as a non-communicable as well as lifestyle disease and is a major health burden worldwide. It has been known for a long time that cancer cells consume large amounts of sugar (glucose) than normal cells but this has been ignored as a source of treatment and management of cancer. Our research takes advantage of this phenomenon to develop drugs that can selectively kill cancer cells. Furthermore, we investigate the impact of sugar in the management of cancer. We think that it may be critical that cancer patients manage the amount of sugar that can be derived for their diet.

Prof Gerhard Prinsloo

Metabolomics and medicinal plants

South Africa is rich in plant biodiversity with more than 25 000 species of flowering plants of which more than 3000 are used for medicinal purposes. Cultivation of indigenous plants used as food, medicine and cosmeceuticals, has become an important research field to commercialise our countries’ bio-resources. Metabolomics is the study of all the metabolites at a given time period and identify changes in the chemical profile as a result of the plant’s environment. The chemical changes are linked to the biological activity of plants and therefore affects the medicinal activity and related quality of cultivated plants. Metabolomics allows for quantification of the chemical changes and is used to develop quality parameters for commercial production to ensure plant material with the required medicinal activity.

Prof Samantha Gildenhuys

Proteins: Molecular machines and drug targets

A protein biochemist works with viral proteins and drug targets. Proteins play a role in carrying out functions in organisms, if they don’t behave optimally disease can arise. Drugs are designed to bind to proteins and restore optimum function. With the cure not existing for many diseases the identification of new drugs is important. Understanding how virus proteins work during the viral infection process allows for the design of drugs to combat their ability to replicate and cause disease. Virus proteins can also be placed in vaccine formulations to prevent infection, so optimizing vaccine conditions for the proteins makes new vaccines possible that have longer shelf life in harsh conditions. Viral proteins are also robust large molecular machines that can be manipulated to perform biotechnologically important functions. These functions include delivery of drugs to particular cells or tissues or carrying markers for diagnostics to specific sites. Therefore, understanding the details of the mechanics of how virus proteins work allows for these applications.

Last modified: 2020/08/17