Bacterial degradation of coal discard and geologically weathered coal:
- Authors: Olawale, Jacob T , Edeki, Oghenekume G , Cowan, Keith A
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/178694 , vital:40097 , https://doi.org/10.1007/s40789-020-00306-3
- Description: The biodegradation of coal discard is being intensively studied in South Africa in an effort to develop passive methods for the successful revegetation and rehabilitation of waste dumps, to mitigate pollution, and facilitate mine closure. Bacteria were isolated from slurries of coal tailings and diesel-contaminated soil, screened for coal biodegradation competence, characterized, and the colonization and degradation of coal discard and geologically weathered coal investigated using individual isolates and consortia. Ten novel coal-degrading bacterial strains were isolated and characterized, the gene sequences deposited with GenBank, and the (wild-type) strains deposited at Microbial Culture Collection, India.
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Congruence between fine-scale genetic breaks and dispersal potential in an estuarine seaweed across multiple transition zones:
- Authors: Nicastro, Katy R , Assis, Jorge , Serrão, Ester A , Pearson, Gareth A , Neiva, Joao , Valero, Myriam , Jacinto, Rita , Zardi, Gerardo I
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149873 , vital:38908 , https://0-doi.org.wam.seals.ac.za/10.1093/icesjms/fsz179
- Description: Genetic structure in biogeographical transition zones can be shaped by several factors including limited dispersal across barriers, admixture following secondary contact, differential selection, and mating incompatibility. A striking example is found in Northwest France and Northwest Spain, where the estuarine seaweed Fucus ceranoides L. exhibits sharp, regional genetic clustering. This pattern has been related to historical population fragmentation and divergence into distinct glacial refugia, followed by post-glacial expansion and secondary contact. The contemporary persistence of sharp ancient genetic breaks between nearby estuaries has been attributed to prior colonization effects (density barriers) but the effect of oceanographic barriers has not been tested. Here, through a combination of mesoscale sampling (15 consecutive populations) and population genetic data (mtIGS) in NW France, we define regional genetic disjunctions similar to those described in NW Iberia. Most importantly, using high resolution dispersal simulations for Brittany and Iberian populations, we provide evidence for a central role of contemporary hydrodynamics in maintaining genetic breaks across these two major biogeographic transition zones. Our findings further show the importance of a comprehensive understanding of oceanographic regimes in hydrodynamically complex coastal regions to explain the maintenance of sharp genetic breaks along continuously populated coastlines.
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Detecting plant species in the field with deep learning and drone technology:
- Authors: James, Katherine M F , Bradshaw, Karen L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160445 , vital:40446 , https://0-doi.org.wam.seals.ac.za/10.1111/2041-210X.13473
- Description: Aerial drones are providing a new source of high‐resolution imagery for mapping of plant species of interest, amongst other applications. On‐board detection algorithms could open the door to allow for applications in which drones can intelligently interact with their environment. However, the majority of plant detection studies have focused on detection in post‐flight processed orthomosaics. Greater research into developing detection algorithms robust to real‐world variations in environmental conditions is necessary, such that they are suitable for deployment in the field under variable conditions. We outline the steps necessary to develop such a system, show by example how real‐world considerations can be addressed during model training and briefly illustrate the performance of our best performing model in the field when integrated with an aerial drone.
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Do spotted hyaenas outcompete the big cats in a small, enclosed system in South Africa?:
- Authors: Comley, Jessica , Joubert, Christoffel J , Mgqatsa, Nokubonga , Parker, Daniel M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150099 , vital:38940 , doi:10.1111/jzo.12772
- Description: Carnivores are adapted to kill, meaning sympatric carnivores can have particularly aggressive and harmful competitive interactions. The co‐existence of multiple carnivores in an ecosystem could be restricted by their similarity in ecological niches (e.g. dietary overlap); however, high prey abundances could facilitate their co‐existence. Although the development of small, enclosed reserves (over 400 km2) in South Africa has reduced human–carnivore conflict, these systems may increase the likelihood of carnivore intra‐guild competition due to the clumping of competing carnivores into these restricted spaces. Using carnivore scat and kill site analyses, we determined the dietary preferences and overlap of sympatric large carnivores in a small, enclosed reserve, Selati Game Reserve (Selati).
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In Vitro Release Testing (IVRT) of Topical Hydrocortisone Acetate Creams: a novel approach using positive and negative controls
- Authors: Mudyahoto, Nyengeterai Amanda , Rath, Seeprarani , Ramanah, Ashmita , Kanfer, Isadore
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149849 , vital:38888 , dx.doi.org/10.14227/DT270120P6
- Description: The objective was to develop and validate an in vitro release testing (IVRT) method to assess the release of hydrocortisone acetate (HCA) from five topical formulations. A marketed generic cream containing 1% HCA was used as the reference product. Vertical diffusion cells (VDCs) were used to assess and compare the release rates of HCA from cream formulations containing 0.5%, 1%, and 1.5% HCA. The study describes a novel approach to test the discriminatory power by including both positive and negative controls to declare pharmaceutical equivalence or inequivalence. The validated method was found to be sensitive, linear, precise, reproducible, robust, and selective for the analysis of HCA from topical cream products. Equivalence or inequivalence was established based on SUPAC-SS acceptance criteria using a 90% CI with limits of 75–133.33%. The IVRT method was shown to have discriminatory ability to appropriately measure significant differences in drug release from various cream formulations. This approach also provides useful information for the future development of acceptable IVRT methods to assess topical dosage forms for local action containing different drugs.
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Reconstructing the distribution of the non-native sea anemone, Diadumene lineata (Actiniaria), in the Canadian Maritimes: local extinction in New Brunswick and no regional range expansion in Nova Scotia since its initial detection
- Authors: Ma, Kevin C K , Glon, Heather E , Hawk, Heather L , Chapman, Cody N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/179054 , vital:40095 , https://doi.org/10.1016/j.rsma.2020.101049
- Description: Since its first observations in New Brunswick (Sam Orr’s Pond) and Nova Scotia (Bedford Institute of Oceanography in Dartmouth) in 2009 and 2013, respectively, Diadumene lineata has been observed spreading to new locations in the Canadian Maritimes. In 2017 and 2018, regional surveys for non-native species did not detect D. lineata in New Brunswick, suggesting local extinction. Recent surveys also did not detect D. lineata in Prince Edward Island. However, between 2013 and 2018, D. lineata was detected in Nova Scotia (in chronological order) from Lunenburg Harbour (Lunenburg), Hermans Island (Lunenburg), Black Rock Beach (Halifax), Oak Island Marina (Chester), and Dartmouth Yacht Club (Dartmouth).
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Repurposing a polymer precursor: Synthesis and in vitro medicinal potential of ferrocenyl 1, 3-benzoxazine derivatives
- Authors: Mbaba, Mziyanda , Dingle, Laura M K , Cash, Devon , de la Mare, Jo-Anne , Laming, Dustin , Taylor, Dale , Hoppe, Heinrich C , Edkins, Adrienne L , Khanye, Setshaba D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165395 , vital:41240 , https://doi.org/10.1016/j.ejmech.2019.111924
- Description: Cancer and malaria remain relevant pathologies in modern medicinal chemistry endeavours. This is compounded by the threat of development of resistance to existing clinical drugs in use as first-line option for treatment of these diseases. To counter this threat, strategies such as drug repurposing and hybridization are constantly adapted in contemporary drug discovery for the expansion of the drug arsenal and generation of novel chemotypes with potential to avert or delay resistance. In the present study, a polymer precursor scaffold, 1,3-benzoxazine, has been repurposed by incorporation of an organometallic ferrocene unit to produce a novel class of compounds showing in vitro biological activity against breast cancer, malaria and trypanosomiasis.
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Topsoil transfer from natural renosterveld to degraded old fields facilitates native vegetation recovery:
- Authors: Ruwanza, Sheunesu
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148639 , vital:38758 , https://doi.org/10.3390/su12093833
- Description: The transfer of soils from intact vegetation communities to degraded ecosystems is seen as a promising restoration tool aimed at facilitating vegetation recovery. This study examined how topsoil transfer from intact renosterveld to degraded old fields improves vegetation diversity, cover, and composition. Transferred topsoil were overlaid on 30 quadrats, each measuring 1 m2, in May 2009. Eight years following the initial soil transfer, vegetation diversity in the soil transfer site showed an increase towards the natural site compared to the old field site where no soil transfer was administered. Both species richness and cover for trees and shrubs in the soil transfer site increased towards the natural site, though this was not the case for herbs and grasses. One-way analysis of similarity (ANOSIM) showed significant (R = 0.55) separation in community composition between sites. The study concludes that soil transfer from intact renosterveld to degraded old fields is a promising restoration technique because it increases species diversity and cover and facilitates vegetation recovery. A significant restoration implication of this study is that soil transfer introduces key renosterveld native tree and shrub species that can facilitate successful restoration and act as restoration foci or nurse plants.
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UN Decade on Ecosystem Restoration 2021–2030: what chance for success in restoring coastal ecosystems?
- Authors: Waltham, Nathan J , Elliott, Michael , Lee, Shing Yip , Lovelock, Catherine , Duarte, Carlos M , Buelow, Christina , Simenstad, Charles , Nagelkerken, Ivan , Claassens, Louw , Wen, Colin K-C , Barletta, Mario , Connolly, Rod M , Gillies, Chris , Mitsch, William J , Ogburn, Matthew B , Purandare, Jemma , Possingham, Hugh , Sheaves, Marcus
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149836 , vital:38887 , https://doi.org/10.3389/fmars.2020.00071
- Description: On 1 March 2019, the United Nations (UN) General Assembly (New York) declared 2021–2030 the “UN Decade on Ecosystem Restoration.” This call to action has the purpose of recognizing the need to massively accelerate global restoration of degraded ecosystems, to fight the climate heating crisis, enhance food security, provide clean water and protect biodiversity on the planet. The scale of restoration will be key; for example, the Bonn Challenge has the goal to restore 350 million km2 (almost the size of India) of degraded terrestrial ecosystems by 2030. However, international support for restoration of “blue” coastal ecosystems, which provide an impressive array of benefits to people, has lagged. Only the Global Mangrove Alliance (https://mangrovealliance.org/) comes close to the Bonn Challenge, with the aim of increasing the global area of mangroves by 20% by 2030. However, mangrove scientists have reservations about this target, voicing concerns that it is unrealistic and may prompt inappropriate practices in attempting to reach this target (Lee et al., 2019). The decade of ecosystem restoration declaration also coincides with the UN Decade of Ocean Science for Sustainable Development, which aims to reverse deterioration in ocean health. If executed in a holistic and coordinated manner, signatory nations could stand to deliver on both these UN calls to action.
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Understanding the Pyrimethamine drug resistance mechanism via combined molecular dynamics and dynamic residue network analysis:
- Authors: Amusengeri, Arnold , Tata, Rolland B , Tastan Bishop, Özlem
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163022 , vital:41005 , https://doi.org/10.3390/molecules25040904
- Description: In this era of precision medicine, insights into the resistance mechanism of drugs are integral for the development of potent therapeutics. Here, we sought to understand the contribution of four point mutations (N51I, C59R, S108N, and I164L) within the active site of the malaria parasite enzyme dihydrofolate reductase (DHFR) towards the resistance of the antimalarial drug pyrimethamine. Homology modeling was used to obtain full-length models of wild type (WT) and mutant DHFR. Molecular docking was employed to dock pyrimethamine onto the generated structures. Subsequent all-atom molecular dynamics (MD) simulations and binding free-energy computations highlighted that pyrimethamine’s stability and affinity inversely relates to the number of mutations within its binding site and, hence, resistance severity.
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