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28 November 2019 | Story Leonie Bolleurs
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Dr Sandy-Lynn Steenhuisen and Ruth Cozien at a spot high up in the Maloti-Drakensberg World Heritage Site, close to Sentinel Peak, photographing a Drakensberg crag lizard underneath the leaves of the ‘Hidden Flower’.

Flowers high up in the Maloti-Drakensberg World Heritage Site made world news when it was discovered that the Drakensberg Crag Lizard is their sole pollinator. 

This first for continental Africa – a plant being pollinated by a lizard – is a discovery by a research group including Dr Sandy-Lynn Steenhuisen, Senior Lecturer in the Department of Plant Sciences and affiliate of the Afromontane Research Unit (ARU) at the Qwaqwa Campus of the University of the Free State (UFS), in collaboration with Dr Timo van der Niet, Prof Steven Johnson, and project leader Ruth Cozien, all from the Pollination Ecology Research Laboratory and Centre for Functional Biodiversity at the University of KwaZulu-Natal.

Besides their work being published in popular news here in South Africa (including an isiZulu article), it has also received coverage in, among others, Belgium, Canada, the Netherlands, and the United States of America. 

Is it a bee, a bird, perhaps a mouse?

‘Hidden Flower’, true to its name, is a plant species with flowers hidden at ground level, underneath the leaves of the plant. Like the leaves, the flowers are also green. With the flowers filled with nectar (up to 1 ml per plant) and strongly scented, one concludes that, just as with other flowers, these flowers must be visited by a pollinator. Is it a bee, is it a bird, perhaps a mouse/non-flying mammal?

According to Dr Steenhuisen, who was brought into the project because of her experience with rodents pollinating proteas, many plants are adapted to attract and be pollinated by a specific animal. They attract their pollinators using particular scents and colours and reward them for their service with, for example, nectar, oil, fragrance, and sometimes even shelter. 

The ‘Hidden Flower’ initially had the group of researchers thinking that it was being pollinated by a non-flying mammal. “Everything about the plant made it look like it should be mammal-pollinated,” Dr Steenhuisen said. 

They investigated all options, using several techniques to assess the contribution of different possible animals to set seed. To further assist them in their quest to find the true pollinator, the team put up motion cameras that recorded activity in the area of the ‘Hidden Flower’. 

Great was their surprise when studying the video material after a week of fieldwork in the mountains, finding shy lizards dipping their snouts in the ‘Hidden Flower’ and lapping up the nectar.

Dr Steenhuisen described this discovery as completely bizarre, exciting, and fascinating. 

To make 100% sure that lizards are pollinating the ‘Hidden Flower’, these animals were excluded from the plants. Results published in a paper in Ecology showed that when the lizards were experimentally excluded from the plants, the number of seeds produced dropped dramatically by almost 95%. This finding helped to further prove their discovery. 

Strong scent and bright orange colour attract

The team researched the new phenomenon and found that although flower visitation by lizards is not unknown, it occurs almost exclusively on oceanic islands. Cozien says one should keep in mind that mountains are like sky islands and might therefore have similarities with oceanic islands in terms of their ecology.

The strong scent and the touch of orange at the base of the inside of the flowers is believed to play an important role in attracting lizards. The little lizard may recognise the spots of orange inside the flowers which resemble the orange colour of a male lizard in mating season, attracting females. Lured by the strong scent and the orange spots, the reptiles stick their snouts into the flower in search of nectar, pollinating the ‘Hidden Flower’; thus, making sure that this flower will continue to grow on the slopes of Sentinel Peak in the Maloti Drakensberg range. 

This research finding on lizard pollination, which reads almost like a fairy tale with its islands, hidden flowers, nectar from the gods, and little dragons, shows that there are still many unknown and surprising interactions that need to be discovered and conserved to ensure a healthy ecological system. 

The research findings of this study were published in April 2019. 

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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