Showing papers in "Transactions of The Royal Society of South Africa in 2022"

Only in Africa: The Ecology of Human Evolution

Abstract: That humans originated in Africa is well-known. However, this is widely regarded as a chance outcome, dependent simply on where our common ancestor shared the land with where the great apes lived. This volume builds on from the ‘Out of Africa’ theory, and takes the view that it is only in Africa that the evolutionary transitions from a forest-inhabiting frugivore to savanna-dwelling meat-eater could have occurred. This book argues that the ecological circumstances that shaped these transitions are exclusive to Africa. It describes distinctive features of the ecology of Africa, with emphasis on savanna grasslands, and relates them to the evolutionary transitions linking early ape-men to modern humans. It shows how physical features of the continent, especially those derived from plate tectonics, set the foundations. This volume adequately conveys that we are here because of the distinctive features of the ecology of Africa.

Medicinal plants sold by West, Central and East African immigrants in Johannesburg, South Africa

Abstract: South Africa hosts >1.2 million immigrants, 75% from Africa. The inter- and intra-continental diaspora of immigrant groups, and the movement of biological commodities, effects a parallel biological diaspora of plants, animals, and pathogens to regions where they are non-native, and an allied diaspora of traditional practices associated with commodity use. Plants with dual purposes of food and medicine are repeatedly introduced into new countries by waves of immigration. The motivation for species selection may reflect cultural importance, geographic origin, and diseases associated with migration. With this in mind, this study aimed to investigate medicinal plants, and their uses, which are imported by immigrant traditional healthcare traders in Johannesburg, and highlight routes of alien plant introduction. Semi-structured interviews with 25 immigrant traders originally from the Democratic Republic of Congo, Ethiopia, Eritrea, Ghana, Nigeria and Somalia were conducted. Sixty-six species were recorded (60 alien to South Africa) that treated conditions in 15 broad biomedical categories. Species were primarily imported to treat non-communicable diseases (NCDs), with the most frequently cited being for diabetes, back pain, influenza, stomach pain, haemorrhoids, and male sexual performance. The use of medicinal plants from ‘home’ is assumed to strengthen an immigrant’s sense of cultural identity in a new country, with some plants seemingly too important to leave behind; the diseases linked to these selections were affiliated more with ‘disease of transition’, including NCDs. Some imported species require assessments of risk to becoming invasive. These results flag the international traditional medicine trade as an introduction pathway for alien plants.

Active restoration in South African fynbos – A long-term perspective from the Agulhas Plain

Abstract: In 2019 we re-surveyed a site on the Agulhas Plain, South Africa, which had been part of a restoration project conducted in 2008. The site was invaded by invasive trees, mainly Australian Acacia species. In the original restoration program, the site had been burned and various treatments (i.e. sowing of competitive, fast-growing native species) were conducted to determine the effectiveness of different restoration strategies. The sowing of native species to assist the recovery process is defined as an active restoration method, whereas passive restoration only removes stressors for the ecosystem (e.g. removal of the invader) and leaves it to recover by itself. For this study, we conducted a vegetation survey at the previously restored sites and compared them with a nearby reference site where no intervention had taken place and which is characterised by near-pristine native fynbos vegetation. Secondly, we compared the new data from 2019 with older data from 2010. However, a decade after the initial restoration effort, both active and passively treated plots had not achieved the same condition (species richness, diversity, evenness) as the reference site. The results also show that active restoration is most likely unnecessary in fynbos restoration projects where there are nearby patches with native vegetation or the existing native seed bank is of sufficient size. It seems that it is more important to prevent the reinvasion of invasive alien plants so that the vegetation can recover over time without further disruption.

Active restoration in South African fynbos – A long-term perspective from the Agulhas Plain

Abstract: In 2019 we re-surveyed a site on the Agulhas Plain, South Africa, which had been part of a restoration project conducted in 2008. The site was invaded by invasive trees, mainly Australian Acacia species. In the original restoration program, the site had been burned and various treatments (i.e. sowing of competitive, fast-growing native species) were conducted to determine the effectiveness of different restoration strategies. The sowing of native species to assist the recovery process is defined as an active restoration method, whereas passive restoration only removes stressors for the ecosystem (e.g. removal of the invader) and leaves it to recover by itself. For this study, we conducted a vegetation survey at the previously restored sites and compared them with a nearby reference site where no intervention had taken place and which is characterised by near-pristine native fynbos vegetation. Secondly, we compared the new data from 2019 with older data from 2010. However, a decade after the initial restoration effort, both active and passively treated plots had not achieved the same condition (species richness, diversity, evenness) as the reference site. The results also show that active restoration is most likely unnecessary in fynbos restoration projects where there are nearby patches with native vegetation or the existing native seed bank is of sufficient size. It seems that it is more important to prevent the reinvasion of invasive alien plants so that the vegetation can recover over time without further disruption.

Bioactive total triterpenes extracted from fruiting bodies and mycelia of Ganoderma lucidum (Fr.) P. Karst ameliorate doxorubicin-induced myocardial injury in rats

Abstract: The objective of the present study was to study the effects of bioactive total triterpenes extracted from the fruiting bodies and mycelia of the medicinal mushroom Ganoderma lucidum in ameliorating doxorubicin (DOX)-induced cardiomyopathy in rats. Male Wistar rats were divided into ten groups (numbered I–X) with six animals in each group. Animals in all groups received DOX (5 mg/kg b.wt) once daily for three alternate days (cumulative dose 15 mg/kg b.wt). Various doses of total triterpenes were given once daily for five days prior to DOX administration to groups II to IX and then DOX injection continued for three more days. Cardiac injury markers, namely creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and troponin I, in serum were assayed. Activities of endogenous antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH) levels and inhibition of lipid peroxidation in the cardiac tissue were determined. High performance thin layer chromatography (HPTLC) analysis was carried out to determine the chemical profile of total triterpene. Total triterpenes downregulated DOX-induced elevated cardiac injury markers such as CK-MB, LDH and troponin I, upregulated declined SOD, CAT, GPx activities and levels of GSH and also downregulated lipid peroxidation in myocardium significantly. The results indicate that G. lucidum triterpenes prevented DOX-induced oxidative stress leading to myocardial damage in rats. The findings suggest the potential therapeutic use of G. lucidum triterpenes to ameliorate DOX-induced cardiomyopathy.

Bioactive total triterpenes extracted from fruiting bodies and mycelia of <i>Ganoderma lucidum</i> (Fr.) P. Karst ameliorate doxorubicin-induced myocardial injury in rats

Abstract: The objective of the present study was to study the effects of bioactive total triterpenes extracted from the fruiting bodies and mycelia of the medicinal mushroom Ganoderma lucidum in ameliorating doxorubicin (DOX)-induced cardiomyopathy in rats. Male Wistar rats were divided into ten groups (numbered I–X) with six animals in each group. Animals in all groups received DOX (5 mg/kg b.wt) once daily for three alternate days (cumulative dose 15 mg/kg b.wt). Various doses of total triterpenes were given once daily for five days prior to DOX administration to groups II to IX and then DOX injection continued for three more days. Cardiac injury markers, namely creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and troponin I, in serum were assayed. Activities of endogenous antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH) levels and inhibition of lipid peroxidation in the cardiac tissue were determined. High performance thin layer chromatography (HPTLC) analysis was carried out to determine the chemical profile of total triterpene. Total triterpenes downregulated DOX-induced elevated cardiac injury markers such as CK-MB, LDH and troponin I, upregulated declined SOD, CAT, GPx activities and levels of GSH and also downregulated lipid peroxidation in myocardium significantly. The results indicate that G. lucidum triterpenes prevented DOX-induced oxidative stress leading to myocardial damage in rats. The findings suggest the potential therapeutic use of G. lucidum triterpenes to ameliorate DOX-induced cardiomyopathy.

Assessing the intraurban differences in vegetation coverage and surface climate in a heterogeneous area

Abstract: Urban trees play a critical role in alleviating land surface temperatures in cities. In remote sensing studies, vegetation indices are widely used to examine the relationship between Land Surface Temperature (LST) and vegetation cover. The vegetation cover can be measured using the Normalised Difference Vegetation Index (NDVI). In this study, the LST-NDVI relationship was assessed in each of the seven city-regions (A-G) in Johannesburg using Moderate-Resolution Imaging Spectroradiometer (MODIS) datasets to provide a basis for urban ecological planning and environmental protection. This study's specific objective was to determine the intraurban differences in vegetation coverage and LST in the seven city-regions over 19 years. The relationship between LST and NDVI was also examined over the years of study. The results showed a significant intraurban difference in LST and NDVI values in the city-regions with a negative correlation between them, ranging from −0.03 to −0.76. The LST values increased in all the city-regions with the highest value of 20.1°C in city-region G, followed by 19.6°C in city-region E. The vegetation cover decreased over the years, with the lowest NDVI value in city-region G (0.39), followed by city-regions F (0.43) and D (0.48). The city-regions with high LST and low vegetation cover include the city-centre and highly populated suburbs. This indicates that areas with greater vegetation cover have low LSTs and vice versa. These findings provide useful information for municipal authorities and other stakeholders to undertake appropriate decisions to tackle Urban Heat Island (UHI) effects by adopting effective urban planning and management interventions.

Tribute to Professor Brian Robert Allanson

Abstract: Professor Brian Robert Allanson, the doyen of South African zoology professors, died in Cape Town on 10 July 2022 at the age of 94 years. He is survived by his wife, Sue, five children, 12 grandchildren and three great grandchildren. Brian was born in Colombo, Ceylon (Sri Lanka) on New Year ’s Day in 1928 where his father, Arthur, was a marine engineer. The Allanson family moved to the United Kingdom when Brian was an infant and then to Port Elizabeth in 1938. Brian’s passionate interest in biology manifested early in life as he enjoyed dissecting rabbits, rats and all manner of other creatures. He was schooled at Grey High School and studied zoology and chemistry at the University of Natal in Pietermaritzburg, graduating in 1948. Whilst a student at the University of Natal in 1948 Brian took part in a research expedition organised by Dr George Campbell to Maputaland (including Lake Sibaya, an unexplored lake at the time). This trip whetted his appetite for doing research in the area, which eventually came to fruition 20 years later. This episode emphasises the importance of early student involvement in field research. After three years as Assistant Science Master at Hilton College, he earned his master ’s degree in marine biology at the University of Cape Town (UCT) and taught there as a junior lecturer in zoology for a year while commencing his studies for a PhD. In 1955 he joined the Zoology Department at UCTas a junior lecturer under Professor John Day. Later that year he married Sue Nicholson, who was studying librarianship at the university. When Brian received a four-year research fellowship from the Council for Scientific and Industrial Research (CSIR) and the Transvaal Provincial Administration, he and Sue moved to Pretoria where he was tasked with monitoring the health of the rivers that supply water to the province. During this period he was sent to England for a year as a visiting researcher at the Department of Scientific and Industrial Research (DSIR) Water Pollution Laboratories in Stevenage, Hertfordshire, where he completed the write-up for his PhD from UCT. On his return he was appointed Head of the Division of Hydrobiology at the CSIR’s National Institute for Water Research, where he continued his work on rivers and reservoirs. In 1963, at the age of only 35 years, Brian Allanson was appointed Professor of Zoology and Entomology at Rhodes University, a position he held with distinction for the next 25 years. The dashing young professor apparently caused quite a stir in the quiet “City of Saints” and became the university’s first Dean of Research and one of the scholarly giants on the campus. His advice to struggling students was always, “Be strong and of good courage” (Joshua, 1, v 9), or “Go sit quietly and think.” It is no accident that the Department of Zoology and Entomology remains one of the top-performing research departments on the Rhodes University campus. In 1965 Professor Allanson established the Institute for Fresh Water Studies (IFWS) at Rhodes University and became its first Director. In 1968 he established a research station on the shores of South Africa’s largest natural freshwater lake, Lake Sibaya, which became an active hub for research in Maputaland, a poorly studied part of northern Zululand. The Lake Sibaya research programme was funded by the International Biological Programme (IBP) and attracted wide Figure 1. Professor Allanson on the beach staring out over his beloved Knysna Lagoon. Photo: Knysna Basin project.

Waste control in South African construction projects

Abstract: The construction industry contributes significantly to a country’s economy, but at the same time it tends to be a large contributor of waste generation. It is imperative that construction waste be controlled and managed effectively to reduce the negative impacts on the environment. There are various factors that cause waste, so this study aimed to determine these, and to understand the types of waste. A review of the literature indicates that the adoption of lean construction principles could play a positive role, so this was interrogated through a survey of construction managers on ten sites in the Gauteng region, the economic hub of South Africa. The most prevalent waste was found to be brick and concrete, attributed to the lack of skill of the subcontractors’ labour. The most common strategy to manage waste was through training and raising awareness. The two most common forms of lean waste were found to be defects and over-production, with the most prevalent lean tools being JIT and process mapping. The greatest challenges to the implementation of lean construction lie in poor supervisory capacity, low levels of skills in the labour force, cultural diversity in establishing levels of quality, late issue of information and shortage of material.

On elementary complex variable theory applied to generalised sinc(p) and related integrals

Abstract: The elementary application of complex variable theory in an earlier paper [Hey, J.D. 2020. On elementary complex variable theory applied to sinc and related integrals. Transactions of the Royal Society of South Africa 75(3): 295–306] is extended by use of the generalised sinc(p) function defined below, in order to provide some interesting, additional insight into the behaviour of the Borwein integrals, which arise as simple consequences of Jordan’s lemma applied to Cauchy’s theorem. The present treatment is of physical interest in relation to the analysis of spectral line broadening by the electric fields of ion perturbers in laboratory and astrophysical plasmas. Finally, a result, stated as a student problem in the well-known treatise [Whittaker, E.T. & Watson, G.N. 1927. A Course of Modern Analysis, Ch. VI (4th ed.). Cambridge University Press], is formulated in more general terms with the aid of the sinc(p) function. The simplicity of application of the present analytical results is extensively illustrated by numerical tables.

The nexus between drivers of wetland utilisation patterns, land use/land cover change and ecosystem services in two wetlands, Zimbabwe

Abstract: The study assesses the nexus between the drivers of wetland utilisation patterns, land-use and land-cover change (LULCC) and the current status of provisioning and cultural services in Driefontein and Intunjambili wetlands, Zimbabwe. A total of 280 household questionnaires were administered together with semi-structured interviews conducted with key informants in the two wetlands. Qualitative data were analysed using the content analysis method whereas descriptive and inferential statistics were used for quantitative data. LULCC was assessed using Landsat and Sentinel data for the years 1999, 2009 and 2019. Supervised classification was performed using the Maximum Likelihood Classification (MLC) algorithm in ArcMap 10.5. Eighty-six percent of Driefontein and 75% of Intunjambili households indicated that wetland use for horticulture farming was the predominant activity, but for different reasons in the two areas. In Intunjambili wetland, horticultural farming was mainly for subsistence use due to the prevailing semi-arid conditions. This was different from Driefontein, where market availability for horticultural produce was the major factor behind commercialised wetland use. Results of the LULCC analysis showed an increase in the spatial extent of the cultivated area in the two wetland areas, at the expense of vegetation and water and some of the associated ecosystem services. The studied wetlands provide cultural services since they are used as sites for research and academic excursions. The variations in the anthropogenic drivers of wetland use in Driefontein and Intunjambili show that location-specific wetland studies are important to inform appropriate wetland scale utilisation and management policies and strategies that result in the maintenance of ecosystem services.

Therapeutic potential and physicochemical standardisation of Lesotho propolis based on geographical location and botanical sources: a pilot study in Mohale’s Hoek district

Abstract: We evaluated the therapeutic potential and physicochemical characteristics of propolis samples collected from three councils, namely Khoelenya (F03), Lithipeng (F04) and Thaba-mokhele (F05), in the Mohale's Hoek district, Lesotho. The aim of this study was to investigate the relationship of the therapeutic potential, physicochemical characteristics and colour variation to the geographical location and botanical sources of the collected propolis samples. The collected samples presented remarkable colour variation, ranging from green (25%) to brown (58%) to grey (17%). The highest antioxidant activity was observed in green-coloured propolis samples collected from Lithipeng F04P01 and Khoelenya F03P01, with 2,2–diphenyl–1–picryl–hydrazyl–hydrate (DPPH) half maximal inhibitory concentration (IC50) values of 0.21 and 0.23 mg/mL, respectively. The antioxidant activity (DPPH IC50) did not correlate completely with the total polyphenolic content (R 2 = 0.1733) and total flavonoid content (R 2 = 0.4836). Moreover, the highest antimicrobial activity was observed on grey propolis collected from Thaba-mokhele, F05P04 and F05P03, with minimum inhibitory concentration of 3.13 mg/mL for both samples, especially against Staphylococcus aureus. The qualitative phytochemical analysis detected the presence of polyphenols, alkaloids and flavonoids in all collected samples. Thus, our findings could lead to the formulation of a “local” Lesotho type of propolis that could be used as an official medicine. This could be a big marketing advantage for the Lesotho pharmaceutical and beekeeping industries.

Performance evaluation of pansharpening Sentinel 2A imagery for informal settlement identification by spectral-textural features

Abstract: The diversity of informal settlement morphologies across locales makes their mapping inherently challenging in heterogeneous urban landscapes. The aim of this study was to evaluate the potential of pansharpening techniques on Sentinel 2A data, and textural features, in enhancing informal settlement identification accuracy in a fragmented urban environment. Brovey transform, intensity, hue and saturation transform, Environmental Systems Research Institute (ESRI), simple mean, and Gram–Schmidt techniques were employed to pansharpen multispectral bands of Sentinel 2A, bands 5, 6, and 7 in the first group, and bands 8A, 11 and 12 in another, using an average of bands 4 and 8 as the panchromatic band. The main objective was to investigate the efficacy of pansharpening Sentinel 2A imagery and texture analysis in automated mapping of morphologically varied informal settlements. An evaluation of the quality of fused images was undertaken through computation of the correlation between the spectral values of the original multispectral and pansharpened image. Grey-level-co-occurrence matrix texture features were extracted from the pansharpened images, and subsequently incorporated in the classification process, using a support vector machine classifier. Our results confirm that the Gram–Schmidt fusion technique yielded the highest informal settlement identification accuracy (F-score 95.2%; overall accuracy 91.8%). The experimental results demonstrated the potential of pansharpening Sentinel 2A, and the added value of image texture for a more nuanced characterisation of informal settlements.

Curious notions: reflections of an Imagineer

Abstract: Sometimes a book comes along that does not really fit into any category – Curious Notions is one such book. Filled with fascinating stories about people, animals, science, discoveries, biology, history, and so much more. The use of the word “stories” is deliberate. Writing a book of facts, in the style of an encyclopaedia is relatively easy. Compile the facts and write them clearly, add a few photos or illustrations and it’s done. However, as we all know, facts are great for studying and short-term recall. However, they seldom touch our hearts, or draw us into a new world. Writing stories is different. There is an increasing evidence of the value of storytelling in science communication as stories are a powerful way to communicate. But telling stories often scares scientists, who are repeatedly told to remove any form of emotion, humour, or anything vaguely personal from their writing. Science, we have thought, is all about the facts, and definitely not about the people behind the discoveries. Stories, which put people at the centre, have been thought of as emotional and creative. Somehow scientists have feared that the use of a story would somehow lower the value of the science. It is little wonder then that scientists baulk at the thought of telling a story about their work. But stories can excite, touch, teach, inspire, motivate, and challenge. In fact, stories are a more powerful motivator of action than are mere facts, and stories about the people that do the science are increasingly important as we personalise science and make it accessible. Reading, or listening to a delightful story draws you in, you become an active participant rather than a passive observer. And this is what Mike Bruton has achieved with Curious Notions. From the first few pages the reader is drawn into a world of discoveries, and of the people who made those discoveries. The first few chapters on early scientists reveal that science has its roots in observation and philosophy, and that the discoveries were made by fallible humans, each with their own idiosyncrasies. This “humanising” of science makes it accessible to everyone – from a budding biologist to a grandmother. The integration of art and creativity with science and social justice is clearly addressed in the chapter “Creativity in the arts and sciences”. This is a broad chapter that neatly weaves stories about science and people, the arts and creativity into topics ranging from politics and human rights to the environmental movement and health. Several chapters explore history. The “Finding Old Fourlegs” chapter on the discovery of the coelacanth, a topic about which the author is very familiar, focuses on the people who made this scientific discovery, rather than the fish itself. This makes the story relatable and is one of the reasons why the story of the coelacanth is still remembered today and told in classrooms around the country. The evolution of the bicycle is another largely historical chapter filled with fascinating facts and people. The chapters on African inventors and Nobel Prize winners were revealing and showed how under-rated African inventors, scientists, authors, environmentalists, and humanitarians are. Did you know that immigrants living in South Africa, or people born in South Africa, were responsible for the invention of, amongst many other items – the dolos harbour protection device, the Policansky lever-drag fishing reel, the Kreepy Crawley, the Jetmaster fireplace, Pratley putty, and of course who could forget Mrs Balls and her famous chutney or Freddie Maakie’s vuvuzela! More recent inventors include Siyabulela Xusa, Mulalo Doyoyo, and Sandile Ngcobo. These three brilliant scientists’ work is contributing to how we can use technology to build a more sustainable future. As an ichthyologist I particularly enjoyed the chapter about the naming of fish, as many of the unique names are familiar to me. Again, this reveals the human side of science, as whom a scientist selects to name a fish or a tapeworm after, says as much about the scientist as the person they named for the animal! One of my favourites is the Ornate sleeper-ray Electrolux addisoni named by Leonard Compagno and Phil Heemstra in 2007 after a popular brand of vacuum cleaner – the Electrolux, and avid diver Mark Addison, who was the first to notice that this was a new species. The two chapters which explored “South Africa’s strangest animal” were like a whistle-stop tour through a few years of university biology. Written in an easily accessible manner, the author explores animals from sponges to saw fish, bluebottles to bats, worms to whales, pangolins to platannas and much more in between. And which is South Africa’s strangest animal? Well, you will have to read the book to find out! “Lessons from the Dodo” is a sobering reminder of the vulnerability of the creatures that we share this planet with. This chapter complements the final chapter which reminds us that ultimately our science should be in the service of both humanity and planet earth – the only life support systemwe have. All of our wonderful discoveries and the amazing progress we have made in science, all of our incredible creativity in the arts and the amazing progress that has been made in human wellbeing and social justice will ultimately be worthless if we cannot find a way to live sustainably, within the carrying capacity of the earth. This is now our biggest challenge as scientists, as artists, as humanitarians, and as humans. Each of us has the power to make the right choice. Enjoy this book, dip into it regularly when you feel the need to be amused or inspired, entertained, or educated. As my mother said – it was the perfect “COVID-19” lock down book. A book for anyone interested in historical facts, science, creativity, and the arts, and above all the people behind it all.

Arsenic poisoning results from the postharvest use of calcium carbide to ripen <i>Citrus sinensis</i> (L.) Osbeck. fruits

Abstract: The use of calcium carbide (CaC2) to ripen Citrus sinensis (L.) Osbeck and other non-climacteric fruit is prevalent in parts of the Global South. However, little to no information exists about the potential effects and risks associated with such practices. Hence, it is necessary to determine if contaminants like arsenic that are associated with CaC2 accumulate significantly in orange juices after they are ripened with the chemical. Fresh mature but unripe C. sinensis were harvested from an orchard in Benin City, Nigeria, and exposed to the different concentrations (1.0, 2.5, and 5.0 g) of dry and wet CaC2 in small lidded cylindrical containers with a surface area of 1507.96 cm2. In each container, three oranges were placed while the control setup was allowed to naturally ripen. The control oranges began to ripen on the 7th day, with severe colour loss, whereas the oranges treated with 5.0 g CaC2 (dry) began to ripen on the second day. However, there were already signs of rotting by the sixth day. Even though the orange exposed to 5.0 g CaC2 (wet) began to ripen after 24 h, there were no symptoms of fruit degradation after one week. Moreover, in oranges ripened with CaC2, there was a large deposition of arsenic. The dried and wet-CaC2-exposed oranges showed no significant variations in arsenic accumulation. It was found that the oranges contain 2.15 mg/L juice and 2.06 mg/L peel material. The use of CaC2 for fruit ripening is discouraged and could contribute to reducing the incidence of cancer, skin lesions, poor cognitive development, and non-communicable diseases like diabetes caused by arsenic exposure.

Susceptibility status of the malaria vector, Anopheles arabiensis to insecticides used in vector-borne diseases control in areas with heterogeneous sources of pollutants in South-East Tanzania

Abstract: Abstract In malaria-endemic countries, monitoring of insecticide resistance in malaria vectors in areas contaminated with different sources of pollutants is still lacking. This study investigated insecticide resistance and its mechanisms in Anopheles arabiensis across four villages in Southeast Tanzania. Mosquitoes were collected from breeding habitats and tested against permethrin, deltamethrin, lambda-cyhalothrin, pirimiphos-methyl, and bendiocarb. Mechanisms of resistance [P450s enzymes and knockdown resistance (kdr)] were investigated. Comparison of mosquito mortality between sites was performed through one-way analysis of variance (ANOVA) and Tukey–Kramer tests. Anopheles arabiensis was highly resistant to pyrethroid and fully susceptible to bendiocarb and pirimiphos-methyl with mortality ranges of 29%−57%; 37%−65%; 34%−53%; 98%−100%; and 100% in permethrin, deltamethrin, lambda-cyhalothrin, pirimiphos-methyl, and bendiocarb respectively. Anopheles arabiensis mortality, particularly, in permethrin and deltamethrin was significantly higher in less polluted areas (Mofu and Namwawala) p < 0.001 as compared to areas with agrochemicals (Minepa) and domestic pollutants (Ifakara town) (p < 0.01). Moreover, significant involvement of P450s enzymes in pyrethroid resistance was observed while kdr mutations were not detected. The present study shows that pollution of mosquito breeding habitats might accelerate insecticide resistance which could impede the control of malaria vectors.

Metabolites profiling and molecular docking identification of putative leads from endophytic <i>Phyllosticta capitalensis</i> as modulators of key druggable structural targets of rotavirus A

Abstract: Rotavirus-induced gastroenteritis is a global health concern and the leading cause of death in low-income countries and children under the age of five. While rotavirus A (RVA) vaccines are available, there accessibility and efficacy remain challenging, especially in the third world countries. This has necessitated the need to develop therapeutics to manage RVA infection. This study investigated gas chromatography-mass spectrometry-derived Phyllosticta capitalensis metabolites as potential therapeutics against the key structural proteins [VP8* portion of the VP4 (spike protein), the VP7 (capsid protein), and the VP1 (RNA-dependent RNA polymerase)] of RVA using molecular docking and ADME approaches. The results revealed that four [lup-20(29)-en-one, A’-neogammacer-22(29)-ene, stigmasta-4,7,22-trien-3-α-ol, and fucosterol] of the 67 metabolites had favourable affinity for the three structural proteins and belonged to classes of metabolite of antiviral importance. Further analysis and pharmacokinetic profiling showed that the pentacyclic triterpenoids, lup-20(29)-en-one and A’-neogammacer-22(29)-ene, had the potential to be developed as antivirals against RVA infection and effort is underway in this direction.

Spatio-temporal distribution of Vachellia stuhlmannii (Taub.) in Venetia-Limpopo nature reserve – SPOT-imagery

Abstract: The impact of African elephant (Loxodonta africana) on selected woody plants varies from local extirpation to persistence amid continuous utilisation. Species generally selected by elephants and the way they are foraged makes them vulnerable to high utilisation levels. This paper studied the spatial and temporal distribution of Vachellia stuhlmannii in Venetia-Limpopo Nature Reserve using SPOT ( S ytéme Pour l’Observation de la Terre) imagery. The spatial pattern distribution of the species was computed using the Spatial Point Pattern Analysis (SPPA) and the Complete Spatial Randomness (CSR) of the species was tested using the Nearest Neighbour Ripley’s K(r) function. Results indicate a significant decrease in the area covered by V. stuhlmannii between 2013 and 2017, with a subsequent decrease in the density of the species. This result was positively correlated (Pearson correlation r 3 = 0.796, P = 0.634) to a decrease in annual rainfall. V. stuhlmannii follows an aggregated spatial pattern, which led to the rejection of the null hypothesis (H o) test of complete spatial randomness. Limitation of this study is that the results are based on five-year data between 2013 and 2017. This was influenced by the SPOT data used that is made available commercially. It is recommended that further studies evaluate the species distribution and density prior to 2013 to determine whether the decrease is because of other browsers, diseases, elephant impact, decreasing annual rainfall or combination of factors.

HIV prevalence among oesophageal cancer patients in rural South Africa

Abstract: Esophageal cancer (EC) is the ninth most common cancer worldwide, with 604,100 new cases each year and ranking sixth in terms of mortality. Individuals infected with human immunodeficiency virus (HIV) have a higher prevalence of certain malignancies compared with the general population. There have been reports suggesting an increased risk of EC among people living with HIV infection. Therefore, this study aimed to investigate the prevalence of HIV infection among EC patients in rural Africa. This is a records-based retrospective descriptive study of patients presenting with EC referred from surrounding hospitals in the Eastern Cape to Frere Hospital from January 2016 to December 2018. A total of 125 EC cases were recorded during this period. Information collected from patients’ records included age, sex, ethnic group, HIV status, tumour location and stage of the disease. Fourteen patients were diagnosed with HIV, translating to a prevalence of 11% (95% confidence interval (CI): 5–15). There was no relationship between the risk of HIV infection and the stages of EC (p = .122). In addition to this, the risk of HIV infection showed no relationship to tumour location (p = .531). In summary, we found that the overall prevalence of HIV infection in EC patients was 11% and this was not associated with the stage or location of cancer at diagnosis in this rural population.

Herd dynamics, phenotypic characteristics of indigenous beef cattle breeds (Bos indicus) in Gokwe North

Abstract: The objective of this study was to evaluate the population dynamics and phenotypic parameters of indigenous beef breeds as well as constraints affecting their conservation in Gokwe North, Zimbabwe. A multi-stage sampling procedure was used to identify participants from three wards (13, 15 and 36), which were randomly selected from five villages (Rusere, Zvichemo, Matendere, Kwashira and Chigova). Purposive sampling was employed to select 155 (60% male and 40% female) households practising beef production. The generalised linear model procedure of SAS (2010) was used to investigate the phenotypic parameters. Results showed that Mashona (60%) was the dominant breed, followed by Tuli (14%), Afrikaner (18%) and their crosses (4%). The average herd sizes were 7.8 ± 0.96, 7.3 ± 0.96 4.8 ± 0.71 for wards 36, 13 and 15, respectively. Lack of grazing, lack of drinking water, low fertility and diseases were the major (P < 0.05) constraints limiting production. Tuli animals had higher (P < 0.05) values of 147.3 ± 0.38, 489.1 ± 0.46, 169.3 ± 0.37, 135.6 ± 0.72 and 35.7 ± 0.28 for body length (BL), body weight (BW), heart girth (HG), height at withers (HW) and shank circumference (SC), respectively. Mature cows weighed up to 301, 322 and 342 kg, whereas the bulls weighed up to 413, 525 and 630 kg for Mashona, Africander and Tuli, respectively. It can be concluded that phenotypic characteristics of indigenous beef breeds vary widely and there is evidence of genetic purity indicated by a lack of variation among wards. It is recommended that breeding programmes target the improvement of maternal traits to suit climatic conditions.

Acyclic halogenated monoterpenes from marine macroalgae: Estimated atmospheric lifetimes, potential degradation products, and their atmospheric impacts

Abstract: The selected acyclic halogenated monoterpenes derived from red macroalgae are investigated in terms of their isolation, their reactions with oxidants (ozone, OH radical) and the impacts of the first-generation oxidation products on the atmosphere. The yields of these monoterpenes from marine algae are small and highly variable (0.01–6.7%), the fractions can then enter the atmosphere through different meteorologically driven processes. The loss of the monoterpenes is mostly driven by OH radical, however, 1,6-dibromo-2,7-dichloro-3,7-dimethyl-oct-3-ene and 4-bromo-8-chloro-3,7-dimethyl-octa-2,6-dienal undergo significant loss via reaction with ozone (>50%). The atmospheric lifetimes of the compounds investigated range from ca. 1.5–10 h. Given their short lifetimes, these compounds can be rapidly oxidised to form a range of stable compounds. The investigation of first-generation products from the OH-initiated oxidation of 5,6-dichloro-2-dichloromethyl-6-methyl-octa-1,3,7-triene, 1,6-dibromo-2,7-dichloro-3,7-dimethyl-oct-3-ene and 4-bromo-8-chloro-3,7-dimethyl-octa-2,6-dienal showed the formation of stable organic hydroperoxides, alcohols and carbonyl compounds which can have significant impact on cloud condensation nuclei as contributors of secondary organic aerosols. Release of free halogen can occur from subsequent product oxidation, notably photolysis of carbonyl type species and these are briefly considered.

Chemical compositions, in vitro assessments of antioxidant and antidiabetic potentials of Cyanomentra vogelii Hook. F.

Abstract: The study investigates the chemical composition and antioxidant and antidiabetic activities of Cyanomentra vogelii Hook. F. Hexane, ethylacetate and methanol extracts of C. vogelii were obtained using a cold extraction method. Phytochemical analysis of the extracts was achieved using standard methods: in vitro assays were employed to assess antioxidant activities while antidiabetic potentials were evaluated against the action of ?-amylase and ?-glucosidase. The chemical composition of the extract was identified using gas chromatography-mass spectrometry (GC-MS) analysis. The methanol extract of C. vogelii displayed the highest quantity of phenol (68.93 mg gallic acid g-1) and flavonoids (74.84 mg quercetin g-1), while the ethylacetate extract exhibited the highest content of proanthocyanidins (33.21 mg catechin g-1). The methanol extract exhibited significantly potent inhibition (P < .05) – more than hexane and ethylacetate extracts – against 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl (OH) and 2,2-azino-bis (3-ethylbenzothiazoline (ABTS) radicals at half maximal inhibitory concentrations (IC50) of 0.58, 0.19 and 0.46 mg/mL, respectively, while hexane extract showed higher metal chelating activity (P < .05) at 0.06 mg/mL. Hexane extract displayed better antidiabetic activities, as revealed by its moderate ?-amylase (2.54 mg/mL) and potent ?-glucosidase (0.53 mg/mL) inhibition compared to other extracts and acarbose. Mixed non-competitive and competitive modes of inhibition were elicited by the hexane extract against the activity of ?-amylase and ?-glucosidase, respectively. The major chemical components with reported antioxidant and antidiabetic activities identified from GC-MS analysis of the methanol extract include phytol (7.26%), n-hexadecanoic acid (5.95%), caryophyllene (1.70%) and nerolidol (2.22%). Cyanomentra vogelii extract contains active phytochemicals with therapeutic potential in the management of diabetes and oxidative stress-related diseases.

Metabolites profiling and molecular docking identification of putative leads from endophytic Phyllosticta capitalensis as modulators of key druggable structural targets of rotavirus A

Abstract: Rotavirus-induced gastroenteritis is a global health concern and the leading cause of death in low-income countries and children under the age of five. While rotavirus A (RVA) vaccines are available, there accessibility and efficacy remain challenging, especially in the third world countries. This has necessitated the need to develop therapeutics to manage RVA infection. This study investigated gas chromatography-mass spectrometry-derived Phyllosticta capitalensis metabolites as potential therapeutics against the key structural proteins [VP8* portion of the VP4 (spike protein), the VP7 (capsid protein), and the VP1 (RNA-dependent RNA polymerase)] of RVA using molecular docking and ADME approaches. The results revealed that four [lup-20(29)-en-one, A’-neogammacer-22(29)-ene, stigmasta-4,7,22-trien-3-α-ol, and fucosterol] of the 67 metabolites had favourable affinity for the three structural proteins and belonged to classes of metabolite of antiviral importance. Further analysis and pharmacokinetic profiling showed that the pentacyclic triterpenoids, lup-20(29)-en-one and A’-neogammacer-22(29)-ene, had the potential to be developed as antivirals against RVA infection and effort is underway in this direction.

Invariance, conservation laws and reductions of some classes of “high” order partial differential equations

Abstract: Using underlying invariance/symmetry properties and related/associated conservation laws, we investigate some 'high' order nonlinear equations. The multiplier method is mainly used to construct conserved vectors for these equations. When the partial differential equations are reduced to the nonlinear ordinary differential equation (NLODE), exact solutions for the ODEs are constructed and graphical representations of the resulting solutions are provided. In some cases, the solutions obtained are the Jacobi elliptic cosine function and the solitary wave solutions. We study the third-order 'equal width equation' followed by a new fourth-order nonlinear partial differential equation (NLPDE), which was recently established in the literature and, finally, the Korteweg–de Vries (KdV) equation having three dispersion sources.

Estimation of soil quality under different soil management practices in the Oxisols soil of Mauritius

Abstract: Soil is considered as one of the most important environmental factors for plant growth. However, the challenge is quantifying the sustainability of soil in agro-ecological systems. Presently, no soil quality assessment has been carried out in the island Mauritius or Small Island Developing States (SIDS) which would help to provide more scientific and precise advice to farmers for fertilisation and/or amendment of the soil. This is a particular handicap when recommendations need to be formulated to shift from conventional agricultural practices to a more sustainable and ecosystem-based approach. The present study attempted to determine the limiting factors of soil quality characterisation following different treatments comprising of mulch, no-mulch, N-based fertiliser, no fertiliser, tillage and no-tillage, and thereafter compare the differences in soil quality with conventional practices. In the present study, soil organic carbon (SOC), bulk density (BD), exchangeable potassium (Ex. K), exchangeable calcium (Ex. Ca), exchangeable magnesium (Ex. Mg), available phosphorous (Av. P), total nitrogen (Total N) and pH were selected as part of the Total Dataset (TDS) and the weighted additive Soil Quality Index (SQIw) of each of the eight treatments was calculated and compared. The study revealed that the SQIs ranged between 0.269 and 0.387 among all treatments, which suggest a low soil quality irrespective of the treatment. On a comparative basis, treatments no-till x mulch x fertiliser, no-till x no-mulch x fertiliser, and tillage x mulch x no-fertiliser are three options that can replace the conventional method tillage x no-mulch x fertiliser (control) based on the SQI.

Exploring the application of ELISA and slot blot as utility protein–protein interaction analysis tools

Abstract: Although protein interaction studies are instrumental in understanding protein networks, most protein interaction techniques depend on use of sophisticated and expensive equipment. This makes it difficult for under-resourced laboratories to conduct protein–protein interaction studies. As such, we sought to explore the prospects of using ELISA and slot blot as alternate methods for analyzing protein–protein interactions in resource-limited settings. We used these two methods to explore the well established interaction of heat shock proteins (Hsps) of Plasmodium falciparum as a model. P. falciparum Hsp70-1 (PfHsp70-1) is a cytosol-nuclear localised molecular chaperone that interacts with several functional partners including P. falciparum Hsp70-Hsp90 organising protein (PfHop), P. falciparum Hsp40 (PfHsp40) and P. falciparum Hsp70-z (PfHsp70-z). To validate the application of ELISA and slot blot techniques in protein–protein studies, we employed these two techniques to explore the interaction of recombinant PfHsp70-1 with its partners. We further used the two techniques to explore the effects of mutating residues located in the GGMP repeat and linker motifs of PfHsp70-1 on the chaperone’s interaction with its functional partners. We established that despite requiring much larger amounts of protein compared to the more sensitive assays, the ELISA and slot blot assays were capable of detecting both nucleotide- and mutation-driven changes regulating the affinity of PfHsp70-1 for its interactors. Our findings highlight the utility of these two techniques under resource constraints in conducting routine protein–protein interaction studies and their possible application in the preliminary screening of inhibitors targeting protein networks.