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28 January 2021 | Story Igno van Niekerk | Photo Supplied
Pictured from the left: Lucas Erasmus from the Department of Physics, Piet le Roux from the Astronomical Society of SA – Bloemfontein, Quinton Kaplan from the Department of Physics, Thinus van der Merwe from the Astronomical Society of SA – Bloemfontein. Front: Prof Matie Hoffman

In his book, The World is Flat, Thomas Friedman mentions how at first countries, then companies, and eventually communities went global. In true flat-world fashion, a combined team of the University of the Free State (UFS) and the Astronomical Society of South Africa – led by Prof Matie Hoffman, Associate Professor in the Department of Physics – participated in a once-in-a-lifetime event with their counterparts from the Ellinogermaniki Agogi School and the Skinakas Observatory in Greece.

On 21 December 2020, Earth was treated to the Jupiter-Saturn conjunction, when the two planets were only 0.1 degrees apart in the sky. Although conjunctions are regular phenomena, NASA mentions that the great conjunction of Jupiter and Saturn in 2020 was the closest since 1623 and the closest observable since 1226! A pinkie finger at arm’s length could cover both planets – although they were still millions of kilometres apart in space.

Planning started months ahead of the event, with the Ellinogermaniki Agogi Observatory in Greece and the Boyden Observatory in Bloemfontein chosen as the two selected vantage points. From both the Southern and Northern Hemisphere, the conjunction would be broadcast live on YouTube. As with any other technical project on an international scale, challenges arose. For example, in the Northern Hemisphere, it was already dark at 17:45 while the South African astronomers were still basking in sunlight until after 19:00. The conjunction would only be visible from South Africa after 19:30, almost two hours after it would be visible in Athens. The time was well used, with the event including a word of welcome by the Consul General of Greece in South Africa, Ioannis Chatzantonakis, presentations on Saturn and Jupiter, as well as a virtual tour of the Boyden Observatory, emphasising its connection with Greece through its first Director, Stefanos Paraskevopoulos. 

On Saturday, 19 December, the teams ‘gathered’ on opposite sides of planet Earth to do a dry run. One could sense the urgency and tension as both teams realised that they would have a huge captive audience on YouTube, and plans had to be made in case of connectivity challenges and if the weather did not allow the conjunction. As preparations progressed, Prof Hoffman was talking to his Greek counterparts and was simultaneously walking around with his laptop to share the landscape and activities via his webcam with colleagues in Greece. 

Monday 21 December 2020 – the weather prediction was correct. Clouds covered the Free State sky and scattered raindrops started to fall. Revert to Plan B. A recording made on Saturday evening was shared via the YouTube link, while a live feed of the conjunction from elsewhere in South Africa was arranged. From both sides of the world, information was shared about the history of the venues, as well as the marvel of what was happening in space. Fortunately, expert planetary photographer Clyde Foster was able to share a live feed just after 19:30 from the observatory at his home in Centurion, Gauteng. Those attending the event where visuals and speakers were together on one screen – yet thousands of kilometres apart – watching an event in outer space, will indeed agree with Thomas Friedman: the world is flat. The live-stream event of the conjunction was a catalyst that will result in continued collaboration between the UFS and colleagues in Greece in the field of astronomy. 

By the time of this writing, the livestream has reached more than 50 000 people.


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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