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13 March 2020 | Story Leonie Bolleurs | Photo Leonie Bolleurs
Team from the UFS Microbiology department
From the Department of Microbiology and Biochemistry, were from the left, front: Dr Mariana Erasmus, Prof Martie Smit, Samantha McCarlie; back: Dr Carmien Tolmie; Samantha McCarlie, Prof Dirk Opperman, and Prof Robert Bragg. They believe publishing in high-impact factor journals reflects the quality of research delivered by the department.

Researchers in the Department of Microbial, Biochemical and Food Biotechnology at the University of the Free State (UFS) published their work in four impact factor eleven journals in 2019/2020, and a fifth was accepted for publication in a journal with impact factor twelve in 2020. 

Two articles were published in Nature Communications, one in Drug Resistance Updates and one in Natural Product Reports. A fifth article is already available as an accepted article at Angewandte Chemie. Researchers in the department work on very diverse topics, as reflected in the titles of these articles: ‘A chemo-enzymatic oxidation cascade to activate C–H bonds with in situ generated H2O2’; ‘Native roles of Baeyer–Villiger monooxygenases in the microbial metabolism of natural compounds’; ‘The genome of a subterrestrial nematode reveals adaptations to heat’; ‘Molecular basis of bacterial disinfectant resistance’; and ‘CYP505E3 – a novel self‐sufficient ω‐7 in‐chain hydroxylase’.

Publishing in journals with a high impact factor is quite an achievement. Publishing in a journal with an impact factor of 3 is considered good and in most fields of study, publishing in journals with an impact factor of 10 or more is regarded as excellent. Impact factors are used to measure the importance of a journal by counting the number of times articles were cited in a certain time period. 

According to Prof Martie Smit, Head of the department, this is a reflection of the quality of research delivered by the department. “It is difficult and takes a lot of time and resources to publish in such high-impact journals.”

Contributing to their success in the department, is the work of their collaborators as well as the quality international postdoctoral researchers the department manages to attract with their emphasis on quality research.

Another highlight in the publication of these articles was that members of the department were corresponding authors of four of the five articles – meaning that the research was conducted in and driven from their laboratories, with UFS researchers taking primary responsibility for the preparation of the manuscripts and communicating with the editors of the journals.

Impacting society

Besides publishing in journals with high impact factors, these researchers are also making a difference to society. Prof Robert Bragg contributed to the study focusing on quality disinfectants. 

We are all aware of the danger of developing resistance to antibiotics. According to Prof Bragg, it is estimated that by 2050, 25 million people could be dying from antibiotic resistance-related bacterial infections per year. He says one of the best options to control diseases – not only bacterial diseases, but also viral diseases such as the Covid-19 outbreak – is good biosecurity and the use of good-quality disinfectants.

Researchers working on this study are trying to understand the development of resistance in bacteria to disinfectants. “This research group is currently investigating the ways in which bacteria become resistant to different high-quality disinfectants. The aim of this work is to discover new methods of resistance and then try to prevent bacteria from becoming resistant to commonly used disinfectants. One of the first aspects that needs investigation is to understand the methods of transfer of genetic information between bacteria. This work formed the basis of the review article written with master’s student Samantha McCarlie on transfer of genes that could code for disinfectant resistance in bacteria,” says Prof Bragg.

Studies about a nematode species discovered 1,3 km deep in a gold mine in Welkom and its ability to survive in extreme environments, made headlines about nine years ago. More extensive research has been performed on deep-space exploration of nematodes surviving extreme environments and were published in Nature Communications. Dr Mariana Erasmus, Assistant Director in the department and Technology Innovation Agency/UFS Saense Platform manager, says the study published in 2019 reveals these nematodes’ adaptation to heat and heat tolerance in an unusual ecosystem isolated from the surface biosphere. More studies on this can help humans learn how to adapt to a warming climate. 

TIA is an agency of the Department of Science and Innovation.

Three of the articles are from the Biocatalysis and Structural Biology group of Prof Dirk Opperman, Prof Martie Smit, and Dr Carmien Tolmie. Biocatalysis is a form of green chemistry that aims to produce chemicals in an environmentally friendly and sustainable manner. The research of the group focuses on using enzymes (proteins performing specialised chemical reactions) to insert an oxygen atom at a specific position in a starting material. Such reactions are difficult to perform using purely organic chemistry. 

The end products are value-added compounds of interest to, among others, the flavour and fragrance industry, which place a high premium on natural products. The work on the novel in‐chain hydroxylase was also patented internationally, because it can be used for the synthesis of a valuable flavour compound.
 
More to come

Besides the commitment of the team in Microbiology, it took multiple institutions, dedicated postdoctoral students, as well as time and money to publish this number of articles in high-impact journals in just over a year. With its 100-plus researchers varying from student researchers to NRF-rated scientists, everyone in the Department of Microbial, Biochemical and Food Biotechnology strives to produce high-quality research. 

And they promise, there is more to come. Watch this space …

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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