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10 July 2018 Photo Supplied
Inaugural lecture focuses on understanding society
Dr Kristina Riedel, Head of the UFS Department of Linguistics and Language Practice with Prof Kobus Marais at his inaugural lecture in May.

Understanding what the terms ‘social’ and ‘cultural’ mean and where they come from is important for Prof Kobus Marais. “If one thinks about it carefully, there was a time in the history of the universe and Earth that terms like ‘social’ and ‘cultural’ did not exist. So, if they did not exist from the very beginning, they must have emerged through some process,” he said at his inaugural lecture held earlier this year.

Prof Marais is a senior lecturer in the Department of Linguistics and Language Practice at the University of the Free State (UFS). His interest is in translation studies, but he is conceptualising translation as a technical term that refers to the semiotic process   in other words, the process through which living organisms create meaningful responses to an environment. 

Semiotics entails the study of signs, and it holds that anything in the universe can act as a sign or be interpreted as one. “A tune can be a sign of resistance against political domination, such as Give me hope, Jo’anna, a song by Eddie Grant, and smoke can be a sign of fire, just as the word ‘rose’ could be a sign of a sweet-smelling flower of any colour,” Prof Marais said. 

The universe is perfused by signs, and we are constantly interpreting them, from traffic signs to buildings to agricultural practices to more abstract things like ‘the law’, ‘politics’, ‘economics’ or ‘religion’. All of these things mean something to us and were made as meaningful responses to an environment.

Inaugural lectures vital part of any university
“Inaugural lectures afford professors the opportunity to table a broader research agenda as well as the opportunity to reflect on meta-disciplinary concerns,” Prof Marais said.

He said during the lecture, he had worked out “a theory of translation that explains some aspects of where social/cultural things come from and how they come to be”. An idea that society, and or culture, are a result of translation processes, that is, “processes in which organisms (human beings in this case) respond to an environment in a meaningful way by creating social relationships and cultural phenomena”. 
“Social and cultural phenomena thus all have a meaningful (semiotic) dimension or aspect that I would like to study,” he said.

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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