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13 November 2020 | Story Leonie Bolleurs | Photo Dr Beanelri Janecke
Five of the multidisciplinary team of researchers and some postgraduate students are determining the depth of soil on the underlying rock layer of the sodic site in the Kruger National Park.

When the Vice-Rector: Research, Prof Corli Witthuhn, invited researchers to apply for funding towards multidisciplinary and interdepartmental projects in 2015, Prof Piet le Roux from the Institute for Groundwater Studies, and the late Dr Fred Kruger from the Centre for Environmental Management took the opportunity and proposed a project to study a catenal ecosystem in the Kruger National Park

According to Dr Beanélri Janecke from the Department of Animal, Wildlife and Grassland Sciences, who led the research team on this project, the team of researchers worked for four years, finding links between the catenal ecosystem (which can be described as a hillslope with different zones forming an environmental gradient from crest to foothill) and processes behind some of its abiotic (non-living) and biotic (living) components. 

Large-scale multidisciplinary research project

All their research on this multidisciplinary project was published in one Special Issue of the Koedoe journal at the end of October 2020. Dr Janecke and Prof Johan van Tol from the Department of Soil, Crop and Climate Sciences were guest editors of this special issue. Dr Llewellyn Foxcroft from SANParks is the Editor-in-Chief of the journal. Other UFS departments involved in this project include the Departments of Genetics; Microbial, Biochemical and Food Biotechnology; Plant Sciences; and Zoology and Entomology.

Dr Janecke says there are 12 articles in this issue and, together with the principal researchers (but excluding postgraduate students), there were 12 authors from the UFS (eight departments and divisions in the Faculty of Natural and Agricultural Sciences) and two from SANParks in associated research collaboration with authors from 14 other institutions. 

This special issue of the Koedoe journal covered research on hydrology, flowpaths, and ground water, including the soil types and properties of different zones on the catena. As stated by Dr Janecke, there are also articles on micro-organisms, fungi, and Fusarium in the soil of the root zone of plants (rhizobiome). 

The environment is degrading fast due to human activities, and there is a dire need for research to look at the bigger picture to find solutions on how to conserve ecosystems and not only smaller parts thereof. – Dr Beanélri Janecke

The journal also comprised articles on the vegetation communities and vegetation structure in the different zones. “Research on how the vegetation recovered post-drought of 2016-2017 and on large and small mammals present on the catena and at the closest waterholes was also published. All of these topics were linked in a discussion article on the catenal ecosystem,” says Dr Janecke.

Multidisciplinary research is not conducted very often on this scale. Many researchers will rather focus on one or a few specific aspects of the ecosystem in a specialist research field. 

SANParks introduced supersite concept

Dr Janecke says scientists from SANParks initiated this supersite concept, where research can be focused on specific areas with similar geology and landscapes in the Kruger National Park to generate multidisciplinary data from separate specialist research fields. 

“Our project went one step further and combined different research fields into one project done on a supersite over the same period. This multidisciplinary project created the opportunity for specialist research fields to be published separately in one special issue, but also to combine the expertise in one project that was summarised in a discussion article.”

She believes that the environment is degrading fast due to human activities, and that there is a dire need for research to look at the bigger picture to find solutions on how to conserve ecosystems and not only smaller parts thereof. “There is a need for a more holistic approach to research, and this special issue provides a framework and basis for similar multidisciplinary studies in future,” states Dr Janecke.

This issue is currently widely marketed on all social platforms of the Koedoe journal and AOSIS Publishers, while a podcast interview is also available at:  https://soundcloud.com/aosis-za/koedoe-interview-podcast-2020 (with permission from Louw Lombaard from AOSIS).

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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