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26 October 2021 | Story Nonsindiso Qwabe | Photo Nonsindiso Qwabe
From the right: Dr Ralph Clark,, with fellow researchers, Dr Stephanie Payne, Dr Sandy-Lynn Steenhuisen, Dr Onalenna Gwate and Evelin Iseli, a Swiss PhD student on RangeX at the open top chambers on the Maloti-Drakensberg mountain range.

What impact has global change had on alpine vegetation in our own mountains and those around the world, and why are certain plants in mountains around the world rapidly expanding their ranges?

This is the question on which the Afromontane Research Unit (ARU) on the Qwaqwa Campus will be shining the research lens over the next three years, through Project ‘RangeX’, a multi-institutional research consortium under the Mountain Invasive Research Network (MIREN), with ETH Zurich (Switzerland) leading the research project. The project is underway in the Witsieshoek area of the Free State component of the Maloti-Drakensberg, as part of a global consortium to better understand the ecological drivers of range-expanding plant species in mountains around the world.

South Africa’s participation in the project is led by the ARU Director, Dr Ralph Clark. Other RangeX partners are Germany, Norway, Sweden, Denmark, Australia, China, Chile, and France, with research locations in the Swiss Alps, Himalayas, Andes, Australian Alps, and Scandes.

The official launch of the research site for the Maloti-Drakensberg mountains, which took place on 20 October, marked the beginning of the South African component of globally coordinated research to understand how range-expanding species may affect current alpine environments under future climatic conditions. The launch involved a site visit to the summit of the Maloti-Drakensberg. Situated at 3 100 m above sea level in the Witsieshoek area, the research seeks to determine whether typical range-expanding species might colonise the alpine zone above 2 800 m under a simulated future warmer climate. 

The South African component of RangeX is funded by the Department of Science and Innovation (DSI) through BiodivERsA, an initiative of the European Union’s Horizon 2020, which promotes research on biodiversity and ecosystem services and offers innovative opportunities for the conservation and sustainable management of biodiversity.
Speaking at the launch of the project, Dr Clark said the alpine zone of the Maloti-Drakensberg is an ecologically severe environment, resulting in only specialised species being found above 2 800 m. “However, with climate warming, it can be expected that many lower elevation plants might start to ‘climb’ the mountain and invade its upper reaches. This will have a major impact on ecology, livelihoods, endemic alpine species, and water production.”

This is the first time that such experiments will be undertaken in the alpine context of the Maloti-Drakensberg, Dr Clark explained. The ARU is using this project to promote an ambitious and long-term alpine research programme centred on the Mont-aux-Sources area, where the Free State, KwaZulu-Natal, and Lesotho meet.  

Toto Matshediso, Deputy Director: Strategic Partnerships at DSI, said the Range X project with South African funding from the DSI was aligned with the departmental priorities for investment in global change and biodiversity research and innovation. 

“The research conducted is strengthening international cooperation in terms of research collaboration with its European Union partners as a region, as well as bilateral partners involved in the project. The project is also located in an area that has been historically disadvantaged, and the DSI is proud to be part of contributors to mountain research initiatives and direct contribution to the local community. The project also places the spotlight on the rich biodiversity data of the area, and how it could contribute to the overall government priorities regarding biodiversity.”

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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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