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23 March 2023 | Story Rulanzen Martin | Photo Stephen Collett
From left: Hanlie Grobler, Senior Officer at the CFM; Prof Koos Terblans, Head of the Physics Department; Nonkululeko Phili, Assistant Officer at the CFM; and Edward Lee, Junior Lecturer and Researcher at the CFM. Photo: Stephen Collett

The Centre for Microscopy (CFM) in the Faculty of Natural and Agricultural Sciences at the University of the Free State (UFS) unveiled a sophisticated JEOL High Resolution Transmission Electron Microscope (HRTEM) during a two-day microscopy conference on 14 and 15 March 2023. The microscope is part of a larger investment into research equipment worth R65 million. 

Speaking at the opening of the conference, Prof Corli Witthuhn, out-going Vice-Rector: Research and Internationalisation, said the microscope purchase “is a significant milestone in the university’s bid for cutting-edge research”. The HRTEM is part of a larger consignment of JEOL equipment at the UFS and, according to Dr Sarah Harper from JEOL UK, it places the UFS in a unique position.  

UFS at the forefront in using electron microscopes  

The HRTEM microscope can be utilised across disciplines and will give the UFS an advantage in uncovering new solutions and creating national and international interdisciplinary research collaborations. “The UFS is at the forefront in this field in SA and continues to push the boundaries,” Prof Witthuhn said. This move will also positively impact the training of honours, master’s, and doctoral students. 

Prof Danie Vermeulen, Dean of the Faculty of Natural and Agricultural Sciences, reiterated Prof Witthuhn’s sentiments by saying that this equipment will set the faculty apart from its competitors. “The faculty already reached the goals of Vision 130 by being proactive,” he said. In the past seven years more than R300 million worth of equipment was acquired by the faculty, but he added that to be the best is not just about the best equipment – “the data coming from using this equipment is what will make the real difference”.

Prof Koos Terblans
Prof Koos Terblans opens the conference on 14 March 2023. Photo: Stephen Collett .

Road to the JEOL HRTEM started in 2018

The process of acquiring a HRTEM microscope started in 2018 and was concluded with the purchasing of the JOEL microscopes in March 2020, a few weeks before the first COVID-19 lockdown. The purchase was made possible through the collaboration between the faculties of Natural and Agricultural Sciences and Health Sciences. Thanks to the dedication of staff members in the Centre for Microscopy and Physics, it was possible to accept delivery of the new HRTEM in June 2021. Prof Koos Terblans, Head of the Physics Department and the Centre for Microscopy, who led the entire project, said this was one of the “proudest moments in my career”.  

Installing the equipment involved various university resources, including the University Estates Department, which had to make additional structural changes to the room where the equipment is housed. This included digging two metres into the existing floor and placing the HRTEM on a 70-tonne solid concrete block, to ensure that the equipment was secure and vibration free.

Prof Terblans said now that the HRTEM from JEOL and its supporting equipment – the final piece of the R65 million research investment puzzle – is part of the faculty’s resources, it is up to the scientists and academics to utilise it for innovative research, enhance research productivity, and foster new collaborations. 

Edward Lee
Edward Lee shows the new HRTEM electron microscope to colleagues and conference attendees.Photo: Stephen Collett 

News Archive

Research eradicates bacteria from avocado facility
2017-01-17

 Description: Listeria monocytogenes Tags: Listeria monocytogenes

Listeria monocytogenes as seen under an electron
microscope. The photo was taken with a transmission
electron microscope at the microscopy unit of the UFS.
Bacteriophages (lollipop-like structures) can be seen
next to the bacterial cells.
Photo: Supplied

“The aim of my project was to identify and characterise the contamination problem in an avocado-processing facility and then to find a solution,” said Dr Amy Strydom, postdoctoral fellow in the Department of Microbial Biochemical and Food Biotechnology at the University of the Free State (UFS).

Her PhD, “Control of Listeria monocytogenes in an Avocado-processing Facility”, aimed to identify and characterise the contamination problem in a facility where avocados were processed into guacamole. Dr Strydom completed her MSc in food science in 2009 at Stellenbosch University and this was the catalyst for her starting her PhD in microbiology in 2012 at the UFS. The research was conducted over a period of four years and she graduated in 2016. The research project was funded by the National Research Foundation.

The opportunity to work closely with the food industry further motivated Dr Strydom to conduct her research. The research has made a significant contribution to a food producer (avocado facility) that will sell products that are not contaminated with any pathogens. The public will then buy food that is safe for human consumption.


What is Listeria monocytogenes?

Listeria monocytogenes is a food-borne pathogenic bacterium. When a food product is contaminated with L. monocytogenes, it will not be altered in ways that are obvious to the consumer, such as taste and smell. When ingested, however, it can cause a wide range of illnesses in people with impaired immune systems. “Risk groups include newborn babies, the elderly, and people suffering from diseases that weaken their immune systems,” Dr Strydom said. The processing adjustments based on her findings resulted in decreased numbers of Listeria in the facility.

The bacteria can also survive and grow at refrigeration temperatures, making them dangerous food pathogens, organisms which can cause illnesses [in humans]. Dr Strydom worked closely with the facility and developed an in-house monitoring system by means of which the facility could test their products and the processing environment. She also evaluated bacteriophages as a biological control agent in the processing facility. Bacteriophages are viruses that can only infect specific strains of bacteria. Despite bacteriophage products specifically intended for the use of controlling L. monocytogenes being commercially available in the food industry, Dr Strydom found that only 26% of the L. monocytogenes population in the facility was destroyed by the ListexP100TM product. “I concluded that the genetic diversity of the bacteria in the facility was too high and that the bacteriophages could not be used as a control measure. However, there is much we do not understand about bacteriophages, and with a few adjustments, we might be able to use them in the food industry.”

Microbiological and molecular characterisation of L. monocytogenes

The bacteria were isolated and purified using basic microbiological culturing. Characterisation was done based on specific genes present in the bacterial genome. “I amplified these genes with polymerase chain reaction (PCR), using various primers targeting these specific genes,” Dr Strydom said. Some amplification results were analysed with a subsequent restriction digestion where the genes were cut in specific areas with enzymes to create fragments. The lengths of these fragments can be used to differentiate between strains. “I also compared the whole genomes of some of the bacterial strains.” The bacteriophages were then isolated from waste water samples at the facility using the isolated bacterial strains. “However, I was not able to isolate a bacteriophage that could infect the bacteria in the facility.

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