Vol: 1 | ISSUE:3

CHASING HYPERVELOCITY Chronic inflammation and metabolic syndrome in STARS SA WOMEN

Alien invasion COSTS SA BILLIONS SA’s 200 Million-year old HEAVYWEIGHT Welcome to the third edition of . This newsletter aims to make the research funded by the NRF accessible to all stakeholders, showcasing leading research projects, researchers and related events.

History features a lot this issue. We look at : two which were discovered in China and another, considered to be one of the world’s largest, discovered in the Free State; how hybridisation played a key role in human evolution; and how a star zipping through the Universe holds clues about a CONTENT PAGE supernova that occurred 90 000 years ago. Find out how alien plant and species are costing our economy billions every year. SA ’s 200 researchers look for ways to combat this. Local Million-Year Old Heavyweight...... 4 researchers are also applying science to the art of winemaking for the benefit of this R9 billion industry.

Two New Dinosaurs Offer Race plays a role in the health of South Africans in Glimpse of Insect-Eater Evolution...... 6 an article on non-communicable diseases such as diabetes and cardiovascular disease.

Hybridisation and the A special thanks to our researchers and other staff “Science knows no country, Science of Becoming Human...... 8 members who contributed articles, information and because knowledge belongs to images. Chronic Inflammation and Metabolic is produced by: humanity, and is the torch which Syndrome in South African Women...... 10 NRF Corporate Communications Office Meiring Naude, Brummeria, Pretoria illuminates the world.” Email: [email protected] A Desire to Overcome Addiction - Web: www.nrf.ac.za/science-matters LOUIS PASTEUR Experiences of Nyaope Users...... 12 DISCLAIMER: The views expressed in this publication are not necessarily the views of the National Research The Alien Invasion that is Foundation or its management or governance structures. Costing South Africa Billions...... 14

Science and Wine Can Make for a Healthy Mix...... 17

THINKSTOCK SALT Chases Hypervelocity Stars...... 18

SCIENCE MATTERS | January 2019 3 Advancing Knowledge. Transforming Lives. Inspiring a Nation. various specimens of bipeds and quadrupeds. They found that Ledumahadi, like quadrupeds, had proportionally thicker forelimbs. Osteohistology, the study of bone tissue, was used to calculate the age of the when it died. By closely observing the bone tissue and the growth lines of the bones, Dr Botha-Brink, a vertebrate palaeontologist from the National Museum in Bloemfontein, determined that Ledumahadi was an adult of about 14 years of age when it died, that its growth was slowing in the final years of its life. Finally, to find out when Ledumahadi lived, the rock types and layers where it was found were compared to other areas in the world. Dr Bordy, Associate Professor in the Department of Geological Sciences at the University of Cape Town, found that Ledumahadi had died on a vegetated floodplain in a semi-arid environment Ledumahadi mafube is the first of the true giant much like the present-day Karoo. sauropods of the Jurassic. Quadrupedal postures with flexed limbs potentially evolved several times in sauropodomorph dinosaurs before the evolution of New Ideas on Big Dinosaurs derived, columnar-limbed postures of . The excavation and study of Ledumahadi mafube has led to some new ideas about big dinosaurs and What Ledumahadi mafube may have looked like. Another South African dinosaur, how they lived. For example Ledumahadi enabled tucki, watches in the foreground. Copyright Viktor Radermacher the researchers to deduce that the truly gigantic The excavation and study of Ledumahadi mafube dinosaurs had evolved at least 10 million years earlier was undertaken by a joint research team of scientists than originally thought. The fact that Ledumahadi from South Africa, which included Dr Choiniere, Dr evolved its huge body size and quadrupedal posture Blair McPhee, Dr Jennifer Botha-Brink and Dr Emese independently of other sauropod giants suggests Bordy, and Professor Roger Benson from Oxford that their evolution was considerably more dynamic South Africa’s University in the UK. Funding for the project came than previously thought, with multiple ‘experiments’ from the National Research Foundation and the into four-legged stances. Ledumahadi is also one of 200 Million-Year Old Heavyweight Palaeontological Scientific Trust (PAST). the first dinosaurs to evolve after the mass extinction more than 200 million years ago and shows how Putting the Puzzle Pieces Together rapidly dinosaurs regained enormous body sizes. wice the size of an adult African Lecheko, a guide based at the Mehloding To determe size, shape and other characteristics of elephant, standing four metres high Community Trust near Matatiele. It is a close Ledumahadi, the team compared it to the of Ledumahadi is closely related to another large at the hips and weighing in at 12 relative of sauropod dinosaurs, such as the other known species held in South African sauropod tonnes, this was once the largest land , was a plant eater and stood on collections all over the world. called Antetonitrus, but also animal on Earth. Ledumahadi mafube, four legs. Some of its fossilised remains were to species from Argentina of Ta dinosaur that lived in the region now known as originally discovered 30 years ago in the Clarens To determe its weight, Ledumahadi approximately the same age. the Free State 200 million years ago, has become area of the Free State. Stored in the Wits archive, they took into account the This further supports the idea the latest discovery by an international team of they were only rediscovered in 2000. The full circumference of its thigh bone had died on that the Earth’s continents scientists led by palaeontologist Professor Jonah excavation of the dinosaur was completed in 2016 (femur) which suggested a a vegetated were once connected in a Choiniere from the University of the . although the last bone, a finger, was discovered very heavy animal. To develop massive landmass called accidently in 2017 and provided the scientists with an idea of its posture, the floodplain and shows how Ledumahadi mafube means “a giant thunderclap critical information on the uniqueness of the new team visited various museums easily dinosaurs could have at dawn” in Sesotho and was named by Puseletso specimen. around the world to measure walked from place to place.

4 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 5 Alvarezsaurs evolved short arms only later in their evolutionary history

members had less teeth and evolved a hand with a huge single claw capable of, perhaps, tearing open Co-lead authors, Prof Jonah Choiniere (left) and Prof Xu Xing (right), working on an alvarezsaur skull at the rotting logs and anthills. IVPP, Beijing, China (Credit: Prof. Jonah Choiniere) “The new fossils have long arms, and so show that alvarezsaurs evolved short arms only later in their study was made possible by a joint South Africa/ evolutionary history, in species with small body sizes. China collaborative grant through the National This is quite different to what happens in the classic Research Foundation of South Africa, held by Profs example of tyrannosaurs, which have short arms and Xu and Jonah Choiniere from the University of the giant size,” said co-author Professor Roger Benson Artist’s reconstruction of important alvarezsaur species. from left to right, Witwatersrand. of Oxford University. Haplocheirus, Xiyunykus, Bannykus, and Shuvuuia. Note the lengthening of the jaws, reduction of the teeth, and changes in the hand and arm (Credit: Viktor Radermacher) From meat-lovers to insect-eaters A missing piece of the evolutionary puzzle According to the study, both Xiyunykus and Until now, researchers have been unable to explain Bannykus are classified as alvarezsaurs, a sub-group the change in the anatomy and behaviour of of theropod (meat-eating) dinosaurs. alvarezsaurs as there was a gap in the fossil record Two New Dinosaurs Offer of about 70 million years. Haplocheirus, which lived “Alvarezsaurs are weird ,” said Prof Choiniere, around 160 million years ago, is the earliest known Glimpse of Insect-Eater Evolution who is a leading member of the team and a co- member, while the later alvarezsaurs are thought to author of the study. “With their strong, clawed hands be younger than 100 million years. Thus, Xiyunykus An unusual line of bird-like dinosaurs discovered in China is changing and weak jaws, they appear to be the dinosaurian and Bannykus, whose fossils are estimated to be the way we understand the evolution of some of these predators analogue to today’s aardvarks and anteaters.” between 110 million and 130 million-years old, fits perfectly within this gap. ut alvarezsaurs did not start out as insect- eaters. The earliest members of the group Xiyunykus and Bannykus weigh an estimated 15kg b had more typical meat-eating teeth and and 24kg respectively and would have been fast ention “meat-eating dinosaur” The two new specimens were discovered during hands, useful for catching small prey. Later-evolving runners. Their perceived agility is still a mystery – it and the toothy Tyrannosaurus rex collaborative international fieldwork in China, co- was likely used to avoid predators rather than to hunt with its giant body and tiny arms led by Profs Xu Xing of the Institute for Vertebrate for prey. will likely come to mind. However, Palaeontology and Palaeoanthropology in Beijing, not all of these ancient carnivores and James Clark from George Washington University “The fossil record is the best source of information Mstarted out or ended up looking like the iconic T-rex. in Washington DC. Xiyunykus was discovered in Xiyunykus and about how anatomical features evolve,” said James The discovery of two bird-like dinosaurs in China, 2005 in Xinjiang, north-western China. Bannykus Clark, co-author and an Honorary Professor at Xiyunykus and Bannykus, could hold the key to was discovered a few years later in 2009 in Inner Bannykus are classified Wits University, “and like other classic examples of understanding the evolution of an unusual line of Mongolia, north-central China. as alvarezsaurs evolution such as the ‘horse series’, these dinosaurs predators that roamed the Earth millions of years show us how a lineage can make a major shift in its ago. Once the fossils were discovered, their further ecology over time.”

6 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 7 hat do you get when you cross a Homo sapiens with a Homo neanderthalensis? This might sound W like the beginning of a palaeontology joke but in reality it asks a pertinent question where the punchline is “us”.

Professor Rebecca Ackermann, Professor in the Department of Archaeology at the University of Cape Town and Director of UCT’s Human Evolution Research Institute (HERI), has made a series of in- depth studies of hybridisation and how it has served as an essential creative force in the emergence of modern humans. Her research goes back nearly two decades, beginning with a study of the bones of baboons that showed certain anomalies in the bone structures which indicated that they were, in fact, hybrids. LEFT: Professor Rebecca Ackermann in HERI laboratory (credit: Kerryn Warren; Cape Town). CENTRE: Dr She documented her findings and used them as an Lauren Schroeder in bone room at SUNY Buffalo (credit: Douglas Levere; Buffalo, NY). RIGHT: Dr Kerryn analog for understanding human evolution. With the Warren as Underground Astronaut excavating (credit: Kerryn Warren; Gauteng, Rising Star Cave) help of her PhD students, Dr Lauren Schroeder and Dr Kerryn Warren, and other colleagues, Professor Ackermann’s research has expanded beyond measuring the skulls of baboons, to the skeletons of The Benefits of Hybridisation that resulted in hybridisation between species would other hybrid animals including gorillas, macaques, Much of Professor Ackermann’s research occurred have influenced the development of modern cultures wildebeest, canids (e.g. wolves and dogs), and even years before hybridisation in human evolution was in a kind of parallel genetic/cultural evolution. As mice. This research is showing that small anomalies confirmed through genetics, making it provocative occurs with genes, cultural contact and exchange such as extra or misaligned teeth are common and highly controversial. However, in recent years, would result in the introduction of variation, in hybrids, as are large size and significant shape her work has been proven correct, and along with innovation and novelty (such as new tool types, differences relative to non-hybridised species, and other scientists, she is showing that hybridisation building methods, etc). these same patterns can be seen in fossil human played a more prominent role in the evolution of ancestors. Says Professor Ackermann, “It is well even new species, many of which turn out to be Homo sapiens than originally thought, and has dds Professor Ackermann, “The idea known that hybridisation has played an important better adapted to new or changing environments. provided fuel for the evolution of a more diverse that one single ancestral group recently role in the evolution of many animals, and that this We now know this is the case for humans, too.” human species. For example, to date researchers abecame human then killed off or otherwise can result in novel organisms, new populations and have shown that the genes of ancient human groups replaced everyone else on the planet simply isn’t such as Neanderthals and Denisovans persist in true. Humans arose through a complex process of living people, and have contributed to the diversity migration, interaction and exchange over hundreds of human skin variation and immunity, among of thousands of years or more. Our ancestors have other things. This suggests that interbreeding was never been easily parcelled into discrete groups, then Hybridisation sometimes beneficial, providing important novelty to or now, an important lesson in today’s divisive times. the hybrids that helped them adapt in new contexts. Rather, our lineage is best represented by a braided stream, with input from many different groups and the Science of Becoming Human We Are Who We Are Thanks To Coming creating the flourishing and adaptable humans of Together today in all our glorious diversity. Had hybridisation The evolution of the human race as we know it today owes a lot to Professor Ackermann and her colleagues also not occurred, it is unlikely that we would have been hybridisation suggest that the patterns of migration and contact as successful as a global species.”

8 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 9 Findings characteristic of black South African women. This study lends support to the existing However, contrary to the researcher’s hypothesis, understanding that increased hsCRP is associated these factors did not affect the ethnic-specific with an adverse metabolic profile, which includes relationship between hsCRP, triglycerides and total increased insulin resistance and a more athrogenic cholesterol. (fat forming in arteries) lipid profile, characterised by higher levels of triglycerides, total cholesterol and n contrast, the ethnic-specific association LDL-C and lower HDL-C. between hsCRP and the lipoproteins I (HDL-C and LDL-C) was explained by Ethnic association between hsCRP and various ethnic differences in socioeconomic status and metabolic risk factors contraceptive use. The researchers highlighted that The study showed that the association between within the South African context, socioeconomic hsCRP and metabolic risk differ between ethnicities. status influences contraceptive use, which they Complications of Diabetes (from LtoR): Retinopathy, Nephropathy and Neuropathy1 Black women have significantly higher levels of showed to be independently associated with hsCRP, compared to white women, when adjusted HDL-C levels. for age and body mass index (BMI). However, Chronic inflammation and metabolic syndrome despite elevated hsCRP, black women were more In this study, most of the black women insulin resistant but had a reported using injectable in South African Women more “favourable” lipid profile, contraceptives, which were compared to white women. mostly the progestin-based The prevalence of certain metabolic diseases such as diabetes and The association injectable contraceptives cardiovascular disease can differ between black and white women in The novel findings in (depot medroxyprogesterone this study were that the between acetate), reportedly South Africa association between hsCRP inflammation associated with a reduction and the lipid markers differed in HDL-C. Conversely, oral outh Africa has seen an increase in non- by ethnicity, such that hsCRP and lipids are contraceptives, predominantly communicable diseases such as Type 2 was positively associated with ethnic-specific used by white women in this S diabetes (T2D) and cardiovascular diseases triglycerides and LDL-C in study, have been associated (CVD) and interestingly the prevalence and incidence white women, and inversely with higher HDL-C. of these diseases differs for black and white South associated with HDL-C in the African women. black women. In conclusion, this study showed that the association between inflammation A cross-sectional study, co-funded by the National Further, the inverse association between hsCRP and lipids are ethnic-specific. Therefore, although Research Foundation, looked at high sensitivity and total cholesterol in the black women was in circulating hsCRP may identify individuals at C-reactive protein (hsCRP), a marker of inflammation direct contrast to the association found in white increased metabolic risk, the heterogeneity of these in the body, which is associated with increased risk Mechanism of normal Blood Sugar absorption (Left) women. The researchers suggest that these ethnic- associations in black and white women highlights of metabolic syndrome, to reveal if the relationship Vs. insulin resistance in Type 2 Diabetes (Right)2 specific associations in the lipid markers could be the need for prospective studies investigating these between hsCRP levels and metabolic risk factors for mediated, either directly or indirectly, by differences associations in different and more representative Type 2 diabetes and cardiovascular diseases differed factors, including insulin resistance, total in socioeconomic status, lifestyle factors or central populations. In addition, these studies should between black and white women. cholesterol (TC), triglycerides (TG), high-density distribution of body fat; factors known to alter examine which factors mediate or influence the lipoproteins (HDL-C), also known as good hsCRP levels and influence metabolic risk. relationship between inflammation and metabolic The study consisted of 194 black and 153 white pre- cholesterol, and low-density lipoproteins (LDL-C), risk in order to design more effective screening and menopausal South African women between the ages known as bad cholesterol; and Socioeconomic status and lifestyle factors interventions. of 18 and 45 years and investigated whether: • The association is influenced by socioeconomic The researchers point to previous studies that have • hsCRP levels differed by race/ethnicity; status and lifestyle factors or racial differences in shown that a higher inflammatory profile is linked • There was race/ethnic-specific association central adiposity (accumulation of fat around the to a lower socioeconomic status, as well as greater 1-2 (Manu5, CC BY-SA 4.0, http://www.scientificanimations.com/wiki- between hsCRP and various metabolic risk abdominal area). central distribution of body fat, both of which are images/)

10 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 11 appearance. In addition, users often resort to stealing Nyaope, or whoonga, A Desire to Overcome Addiction - and selling stolen goods in order to sustain their habit. is a relatively new Physical health vulnerabilities associated with the Experiences of Nyaope Users drug include being prone to infections because of designer drug a compromised immune system and the sharing of By Professor Kebogile Mokwena, Nedbank/NRF South African Research Chair (SARChI) in Substance Abuse needles for those that inject rather than smoke the and Population Mental Health drug. The interactions of the various drugs in the nyaope cocktail contribute to the extreme physical/ physiological dependence on the drug. in the study expressed a desire to find assistance in quitting their addiction. The cry for help message he most significant challenge involved extent to which they wish to access help in quitting Experiences of users of nyaope was identified from the users, their families and the in attempting to quit nyaope use is the the use of the drug. The study found that the experiences of the community. physical pain that occurs when users nyaope users are consistent across all areas, and have not smoked the drug. These are Nyaope, or whoonga, a novel psychoactive their description of the process of addiction is What can be done? some of the experiences revealed in substance (NPS), is a relatively new designer drug similar. Nyaope users identified unfavorable social The study recommends that nyaope users require Ta study by Professor Kebogile Mokwena, who was made by mixing a number of compounds to effect environments which promote initial use and difficulty interventions at different levels, including: recently awarded the Nedbank/NRF South African psychoactive results. Nyaope contains some in quitting, as well as negative views of themselves OO The mental/psychological, Research Chair (SARChI) in Substance Abuse and amounts of heroin to which is added a range of other and their lives due to their use of nyaope, as some of OO The physical pain which result from withdrawals, Population Mental Health, at Sefako Makgatho substances such as methamphetamine, cocaine, the many challenges they face. The negative views and Health Sciences University (SMU). paracetamol, caffeine and even medicinal drugs. reported were informed by how communities and OO Societal factors, which include unfavorable social The drug is predominantly used by young people their families regard the users, and the lack of trust conditions. The research, which reports on the experiences of of lower socio-economic status in black townships and respect that is brought about by their use. nyaope users in Gauteng, Mpumalanga and North in South Africa. Users can be easily identified by While standard rehabilitation programmes typically West, highlights the plight of users in terms of the their dazed look, slow movements and unkempt The study also found that physical pain that occurs remove the addicted person from his or her social when the users have not smoked the drug, was environment for the stipulated period, this alone one of the biggest challenges for users attempting has been found to be insufficient for the nyaope to quit nyaope use, as it often contributed to their addict, as upon return, they often go to the same consistent relapse. Because smoking nyaope unfavourable social environment, which promotes temporarily relieves the pain, the research found a relapse. The research recommends that a that it becomes an easier option for users and customised programme may hold the key to the contributes to a cyclical smoking behaviour. Users successful rehabilitation of addicts. described the strength of the addiction as something they don’t have control over and that once they start The way forward to use the drug they find it difficult to stop. Further research into nyaope is currently underway, led by the SARChI Chair in Substance Abuse and A recent, yet to be published biochemical study Population Mental Health together with various conducted at SMU, also shows that nyaope use is schools at SMU. The studies will look into: associated with a range of abnormalities including OO The effect of nyaope use on sexual function and liver and gonadal dysfunction as well as a range of upper gastro-intestinal tract blood cell count abnormalities. This suggests occult OO The use of physical activity to improve quality of infections, organ dysfunction and possible bone life of recovering nyaope users marrow and immune suppression. OO Radiological and brain function changes OO Impact of nyaope use on the mental status of the Despite the effects of nyaope on the users’ lives, users’ families they do not seem to be able to break the habit. On OO The impact of nyaope on children who are the contrary, researchers found that nyaope users perinatally exposed.

12 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 13 Kangaroo Thorn Boxing glove cactus THE ALIEN INVASION (Acacia paradoxa) (Opuntia fulgida) that is costing South Africa billions The destruction caused by invasive species of plants and animals costs the South African economy billions of rands every year.

Invasive alien species cost South Africa’s economy Why should we be concerned? an estimated R6.5 billion a year and are threatening up to 30% of the water supply in major cities in Reduction in water supply Smallmouth Bass the Western and Eastern Cape, according to a Invasive trees and shrubs reduce water runoff and collaborative report by the DST-NRF Centre of groundwater recharge, reducing the water supplies Excellence for Invasion Biology at Stellenbosch to already-stressed farms, towns and cities, and University and the South African National Biodiversity increases fire hazards and biodiversity erosion. Institute (SANBI). At a national scale, the combined impacts of invasive The Status of Biological Invasions and Their alien plants on surface water runoff have been Management in South Africa estimated between 1 444 to in 201711 is an independent 2 444 million m3 per year. If assessment of the status of no remedial action is taken, biological invasions and their 80 alien plant reductions in water resources management in South Africa. could rise to between 2 589 much larger with up to a 71% loss of grazing in How do invasive species enter South Africa? It is the first country-level species have a and 3 153 million m3 per some biomes. assessment specifically on severe impact year, about 50% higher than Deliberate introduction biological invasions anywhere in estimated current reductions. Loss of biodiversity Most alien species found in the country today were the world. on South Africa’s Invasive plants and animals impact negatively on introduced intentionally. The reasons range from Loss of livestock biodiversity and the services that South Africa’s erosion control and biological control to hunting and Although most alien species are environment Invasive plants reduce the diverse natural ecosystems provide such as fisheries, landscape improvement. Almost all agriculture and beneficial and don’t necessarily capacity of the land (such as livestock production, harvesting of natural products, forestry production is based on alien species and become invasive, others are grassland, savanna and Karoo national and international tourism, and recreation. they are widely used in horticulture, aquaculture, not. vegetation) to support livestock Unsurprisingly, this has a knock-on effect on the mariculture, or are kept as pets. by displacing palatable indigenous plants, thereby country’s economy and food security. To date, 775 invasive species have been identified, also threatening the livelihoods of people who Accidental introduction most of them are terrestrial and freshwater plants depend on livestock production. Reductions in biodiversity intactness in South Africa’s Other alien species found their way into the country (574 species) or terrestrial invertebrates (107 terrestrial biomes were highest (3%) in the fynbos by accident and through various pathways. For species). A total of 107 species were considered by Invasive alien plant infestations are estimated to have biome. Under a scenario where invasive alien plants example, as contaminants on imported plants/seeds experts to be having either major or severe impacts reduced the potential for South Africa to support are allowed to reach their full potential, biodiversity or animals, or as stowaways on visiting ships and on biodiversity and/or human wellbeing – 75% of grazing stock by approximately 115 000 large intactness is predicted to decline dramatically, by aeroplanes, or in the luggage of tourists. these were terrestrial or freshwater plants. stock units – just over 1% of the potential number around 70% for the savanna, fynbos and grassland of livestock that could be supported. If no remedial biomes, and even more (by 87% and 96%) for the There are 72 official ports of entry through which 1 https://www.ncbi.nlm.nih.gov/pubmed/28106664 action is taken, impacts are projected to become two Karoo biomes. people, goods and transport vessels can enter the

14 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 15 country. The rate at which alien species are being OO Feral domestic cats (Felis catus) and house mice introduced has been increasing steadily, from around (Mus musculus) are serious threats to breeding Science and Wine 35 species per decade in the 1950s to 70 species marine birds on offshore islands. per decade between 2000 and 2010. With trade and OO North American smallmouth bass (Micropterus CAN MAKE FOR A HEALTHY MIX tourism ever increasing, accidental introductions will dolomieu) decimate indigenous and endemic fish likely continue to grow. However, it is expected that and invertebrates in streams, rivers and dams. inemaking in South Africa is a conditions have been created. These ecosystems OO rates of deliberate introduction will decrease in future Argentine ant (Linepithema humile) disrupts ant- major industry, producing 10.8 have the added advantage that they can be carefully thanks to improved legalisation. plant mutualisms that are responsible for the seed million hectolitres annually, controlled and easily manipulated for a desired dispersal of indigenous plants, and thus pose almost half of which is exported. purpose. Which invasive species are considered serious threats to indigenous vegetation survival. In fact, it is the second largest problematic? Wagricultural commodity, worth nearly R9 billion in he interactions between yeast and other Measures of control annual exports. A total of 0.12 million hectares of microorganisms, namely bacteria and Alien plants are the most diverse, widespread and land is committed to vineyards, the bulk of which are t microalgae, form the core of this research. More damaging group of invaders in South Africa. Monitoring and control of invasive species are an in the Western Cape, a region which has recently specifically, the interest lies in mutualistic symbioses ongoing process. The good news is that South undergone severe drought conditions that threaten and the role that these beneficial interactions The 107 species considered to have major or severe Africa has achieved major successes in the field of the growing exports and more than 300 000 direct play in shaping the evolution of species within impacts consist of: biological control of invasive alien and indirect jobs supported by the industry. It biologically complex ecosystems. To this end two OO 80 terrestrial or freshwater plants, and is regarded as a world therefore makes sense to combine science with synthetically engineered environments have been plants leader due to the development and oenology, to assist the industry in developing constructed which promote the formation of obligate OO Eight mammals Invasive trees promulgation of comprehensive solutions to improve wine quality and sustainability. mutualisms between yeast and bacteria; and yeast OO Five freshwater fish regulations to manage biological and microalgae under highly selective conditions OO and shrubs Five freshwater invertebrates invasions. Currently, 15 species Research taking place at the Institute of Wine for potential use in each of the applications listed OO Five terrestrial invertebrates are under complete control and Biotechnology at Stellenbosch University, headed up above. The novel approach used here links synthetic OO reduce water Two amphibians a further 19 species under a by Professor Florian Bauer, South African Research ecology with co-evolution to generate strains with OO One bird species runoff substantial degree of control. Chair in Integrated Wine Science, uses synthetic improved phenotypic traits which have a greater OO One marine plant species ecology approaches to characterise the complex affinity for forming stable, mutually beneficial A system of risk assessment interactions which occur between microorganisms associations. Here are a few examples of and permitting to regulate the within wine and winery wastewater ecosystems. invasive species that can have importation of new alien species These wine relevant ecosystems are highly complex In conclusion, these synthetic consortia hold major or severe negative impacts in South Africa: has been in place since 2014. However, only one environments comprised of numerous interacting considerable potential for the wine industry and OO North American mesquite trees (Prosopis) of South Africa’s 72 international entry points is microorganisms which complicates the study of appropriate selection of microorganisms which reduce grazing potential; deplete groundwater consistently monitored to intercept new potential these interactions within the natural environment. complement each other would be key to improving resources; and negatively impact on biodiversity. environmental pests carried by air passengers and In an attempt to mimic these biologically complex the sensorial attributes of wine and for the OO Australian wattle trees (Acacia) reduce grazing in cargo, although additional measures are in place systems, artificial environments which allow the development of self-sustaining biological wastewater potential and surface water runoff, and negatively through the Department of Agriculture, Forestry and study of these interactions under carefully controlled treatment systems. impact on biodiversity. Fisheries to limit the arrival of new agricultural pests. OO North American and European pine trees (Pinus) Vineyards in the South African wine reduce surface water runoff; negatively impact There have also been nine historical attempts at region of Stellenbosch on biodiversity, and increase the fire intensity and eradicating species in South Africa, and three have (Deon Maritz, CC damage done by wildfires. succeeded – the eradication of domestic cats BY 2.0 (https:// OO Herbaceous and succulent species such as (Felis catus) from Marion Island; the Mediterranean creativecommons.org/ licenses/by/2.0), via triffid weed (Chromolaena odorata); famine snail (Otala punctata) from the Western Cape, Wikimedia Commons) weed (Parthenium hysterophorus); pompom and the khapra beetle (Trogoderma granarium) at weed (Campuloclinium macrocephalum), and multiple sites. More species, such as house crows many cactus species severely reduce rangeland (Corvus splendens), have been actively targeted for productivity and thus the livelihoods of rural eradication in Cape Town and Durban, and more people. successes are expected over the coming decade.

16 January 2019 | SCIENCE MATTERS SCIENCE MATTERS | January 2019 17 SALT Chases “Scientists have become the bearers of the torch of Hypervelocity Stars discovery in our quest for knowledge” STEPHEN HAWKING

and discovered three likely candidates, followed up with ground-based telescopes, including the Southern African Large Telescope (SALT). They were found to possess many of the predicted features for survivors The blue trajectory extends 90,000 years into the past, of D6 Type Ia supernovae: a lack of hydrogen and the red trajectory extends 90,000 years into the future. strong signatures of carbon, oxygen, magnesium, and The green circle indicates the remnant of the supernova luminosities and temperatures unlike almost all other G70.0-21.5. Image credit: Shen et al. (2018) stars. The past location of one of the stars is spatially coincident with a known supernova remnant, making he Southern African Large Telescope (SALT) it highly probable that it was ejected from a system was recently involved in the identification of a that underwent a supernova. hypervelocity star, flung across the galaxy by a supernova explosion that occurred 90 000 SALT followed up two of the seven candidate stars years ago. The discovery of this star and two and one was found to have originated from the tothers may help to solve a decades-old debate on supernova explosion. The star has been nicknamed how supernovae occur. D6-1. The combination of Gaia, which measured the high-speed motion of these hypervelocity stars, Type Ia supernovae are the thermonuclear and the ground-based spectroscopic observations, explosions of white dwarfs in binary star systems. which provided a measurement of the radial They are one of the most common types of component of the stars’ motion, has shown that supernovae and have a fundamental importance as these are among the fastest freely moving stars in cosmological distance indicators. Despite this, the our Milky Way Galaxy. nature of the binary system and the details of the explosion has remained a mystery. Much work remains to ascertain precise characteristics of these stars and the explosions The “dynamically driven double-degenerate double- that gave birth to their hypervelocity. It is very detonation” (D6) scenario predicts the possibility likely that they represent the first discoveries of that the other star in the binary surviving companions to Type system is another white dwarf Ia supernovae, and that they that can survive the explosion of confirm the success of the D6 its companion. Such a star would Type Ia model. The team undertaking be flung away from the system supernovae the observations and data when the gravitational pull of its analysis was led by Ken Shen, companion disappeared and are the a researcher at the University would continue zipping away at of California at Berkeley (USA). speeds between thermonuclear The SALT observations were 1 000 and 2 500 km/s. explosions of taken by Marissa Kotze at the Southern African Astronomical A search was made for such white dwarfs Observatory as part of a program hypervelocity survivors in Gaia’s led by Saurabh Jha from Rutgers second data release in April 2018 University (USA).

18 January 2019 | SCIENCE MATTERS