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25 March 2022 | Story Leonie Bolleurs | Photo Charl Devenish
Prof Liezel Herselman Inuagural Lecture
At the inaugural lecture were from the left: Prof Danie Vermeulen, Dean of the Faculty of Natural and Agricultural Sciences, Prof Liezel Herselman, Dr Adré Minnaar-Ontong, Senior Lecturer in the Department of Plant Sciences and Subject Head of Plant Breeding, and Dr Molapo Qhobela, Vice-Rector: Institutional Change, Strategic Partnerships and Societal Impact.

Prof Liezel Herselman, Academic Head of the Department of Plant Sciences at the University of the Free State (UFS),) delivered her inaugural lecture on the Bloemfontein Campus this week (24 March 2022). The theme of the lecture was the ongoing battle against destructive cereal killers. 

With 28 years of extensive experience as a researcher, her work focuses on marker-assisted disease resistance breeding in wheat within a South African context. When she joined the UFS in 2004, Prof Herselman decided to apply her research expertise in marker-assisted breeding to the problems faced by wheat producers in the Free State and Northern Cape. The Free State is one of the major dryland wheat production areas in South Africa, while irrigation wheat is produced along the major rivers in the Northern Cape. 

Protection against fungal diseases

Concentrating specifically on Fusarium head blight (or wheat scab) and three rust diseases – leaf rust, stem rust, and stripe rust – she has done work to provide wheat plants with ‘tools’ to protect themselves against these fungal diseases.

According to Prof Herselman, there are many genes available in different wheat genotypes and related grass species that provide excellent protection against various races of these diseases. “Some of these genes provide protection or resistance from the seedling stage, while others provide resistance at the adult plant stage. We are thus aiming to combine as many of these genes as possible into a single wheat cultivar, without compromising yield and bread-making quality.”

She says the genes are combined by making crosses between resistant and susceptible cultivars or lines. Conventionally, through a time-consuming process, the incorporation of these genes is tested in the greenhouse and field by infecting plants with the disease to see which plants are resistant and which are not.

They can, however, follow the transfer of these genes to newly developed lines by applying molecular markers. Prof Herselman explains: “A molecular marker is a genomic fragment linked to the gene, which we can follow in the offspring we create from the crosses using different DNA techniques in the laboratory. This enables us to select new wheat lines that contain the highest number of resistance genes. The identified best lines are then used in further crosses and/or released as pre-breeding lines to commercial wheat breeding companies.”

Impact on food security

Her research has an impact on society by providing food security to both commercial and small-scale producers, as well as the end users of wheat (people buying bread and other wheat products). As researcher, it is also important for her to send out students to the workplace who can continue with this task in future.

Prof Herselman believes that when cultivars with fungal-disease tolerance or resistance are released and used by producers, it not only reduces the cost of spraying against diseases, but also increases yields by protecting the crop against fungal diseases. “We live in a world where the population is increasing daily, but land available for agriculture is not increasing and some areas are even lost due to urban development. Increasing yield in available production areas will thus have a positive impact on food security,” she says.

Besides contributing to the country’s food security, she takes pleasure in every aspect of her work. Although she misses the hands-on part of the work as academic head of the department and getting her hands dirty, she still enjoys managing the different research projects (from the conceptualisation phase to data analysis and publishing of results). The part she loves the most is to see the growth in her postgraduate students – from the moment they enter the laboratory for the first time until the day they walk out of the laboratory with their degrees. 

“It adds purpose to my life knowing that I have made a difference in a student’s life and equipped him or her with the necessary tools to be successful in the marketplace. Being able to share your knowledge is a gift, but with that gift comes a lot of responsibility as well. I am, however, up for the challenge,” concludes Prof Herselman. 

News Archive

Research contributes to improving quality of life for cancer patients
2016-11-21

Description: Inorganic Chemistry supervisors  Tags: Inorganic Chemistry supervisors

Inorganic Chemistry supervisors in the Radiopharmacy
Laboratory during the preparation of a typical complex
mixture to see how fast it reacts. Here are, from the left,
front: Dr Marietjie Schutte-Smith, Dr Alice Brink
(both scholars from the UFS Prestige
Scholar Programme), and Dr Truidie Venter (all three
are Thuthuka-funded researchers).
Back: Prof André Roodt and Dr Johan Venter.
Photo: Supplied

Imagine that you have been diagnosed with bone cancer and only have six months to live. You are in a wheelchair because the pain in your legs is so immense that you can’t walk anymore – similar to a mechanism eating your bones from the inside.

You are lucky though, since you could be injected with a drug to control the pain so effective that you will be able to get out of the wheelchair within a day-and-a-half and be able to walk again. Real-life incidents like these provide intense job satisfaction to Prof André Roodt, Head of Inorganic Chemistry at the University of the Free State (UFS). The research, which is conducted by the Inorganic Group at the UFS, contributes greatly to the availability of pain therapy that does not involve drugs, but improves the quality of life for cancer patients.

The research conducted by the Inorganic Group under the leadership of Prof Roodt, plays a major role in the clever design of model medicines to better detect and treat cancer.

The Department of Chemistry is one of approximately 10 institutions worldwide that conducts research on chemical mechanisms to identify and control cancer. “The fact that we are able to cooperate with the Departments of Nuclear Medicine and Medical Physics at the UFS, the Animal Research Centre, and other collaborators in South Africa and abroad, but especially the methodology we utilise to conduct research (studying the chemical manner in which drugs are absorbed in cancer as well as the time involved), enhances the possibility of making a contribution to cancer research,” says Prof Roodt.

Technique to detect cancer spots on bone
According to the professor, there are various ways of detecting cancer in the body. Cancer can, inter alia, be identified by analysing blood, X-rays (external) or through an internal technique where the patient is injected with a radioactive isotope.

Prof Roodt explains: “The doctor suspects that the patient has bone cancer and injects the person with a drug consisting of an isotope (only emits X-rays and does no damage to tissue) that is connected to a phosphonate (similar to those used for osteoporosis). Once the drug is injected, the isotope (Technetium-99m) moves to the spot on the bone where the cancer is located. The gamma rays in the isotope illuminate the area and the doctor can see exactly where treatment should be applied. The Technetium-99m has the same intensity gamma rays as normal X-rays and therefore operates the same as an internal X-ray supply.” With this technique, the doctor can see where the cancer spots are within a few hours.

The same technique can be used to identify inactive parts of the brain in Alzheimer patients, as well as areas of the heart where there is no blood supply or where the heart muscle is dead.

Therapeutic irradiation of cancer
For the treatment of pain connected with cancer, the isotope Rhenium-186 is injected. Similar to the manner in which the Technetium-99m phosphonate compound is ingested into the body, the Rhenium-186 phosphonate travels to the cancer spots. Patients thus receive therapeutic irradiation – a technique known as palliative therapy, which is excellent for treating pain. A dosage of this therapy usually lasts for about two months.

The therapy is, however, patient specific. The dosages should correspond with the occurrence and size of cancer spots in the patient’s body. First, the location of the cancer will be determined by means of a technetium scan. After that, the size of the area where the cancer occurs has to be determined. The dosage for addressing total pain distribution will be calculated according to these results.

Technique to detect cancer spots on soft tissue
Another technique to detect cancer as spots on bone or in soft tissue and organs throughout the body is by utilising a different type of irradiation, a so-called PET isotope. The Fluor-18 isotope is currently used widely, and in Pretoria a machine called a cyclotron was produced by Dr Gerdus Kemp, who is a former PhD graduate from the Inorganic Research Group. The F-18 is then hidden within a glucose molecule and a patient will be injected with the drug after being tranquillised and after the metabolism has been lowered considerably. The glucose, which is the ‘food' that cancer needs to grow, will then travel directly to the cancer area and the specific area where the cancer is located will thus be traced and ‘illuminated’ by the Fluor-18, which emits its own 'X-rays'.

In the late 80s, Prof Roodt did his own postdoctoral study on this research in the US. He started collaborating with the Department of Nuclear Medicine at the UFS in the early 90s, when he initiated testing for this research.

Through their research of more than 15 years, the Inorganic Group in the Department of Chemistry has made a major contribution to cancer research. Research on mechanisms for the detection of cancer, by designing new clever chemical agents, and the chemical ways in which these agents are taken up in the body, especially contributes to the development in terms of cancer therapy and imaging, and has been used by a number of hospitals in South Africa.

The future holds great promise
Prof Roodt and his team are already working on a bilateral study between the UFS and Kenya. It involves the linking of radio isotopes, as mentioned above, to known natural products (such as rooibos tea), which possess anti-cancer qualities.

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