Invasive alien aquatic plants in South African freshwater ecosystems:
- Authors: Hill, Martin P , Coetzee, Julie A , Martin, Grant D , Smith, Rosali , Strange, Emily F
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176271 , vital:42680 , ISBN 978-3-030-32394-3 , 10.1007/978-3-030-32394-3
- Description: South Africa has a long history of managing the establishment and spread of invasive fioating macrophytes. The past thirty years of research and the implementation of nation-wide biological and integrated control programmes has led to widespread control of these species in many degraded freshwater ecosystems. Such initiatives are aimed at restoring access to potable freshwater and maintaining native biodiversity.
- Full Text: false
- Date Issued: 2020
Nutrient patchiness, phytoplankton surge-uptake, and turbulent history: a theoretical approach and its experimental validation
- Authors: Schapira, Mathilde , Seuront, Laurent
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149774 , vital:38883 , https://doi.org/10.3390/fluids5020080
- Description: Despite ample evidence of micro- and small-scale (i.e., millimeter- to meter-scale) phytoplankton and zooplankton patchiness in the ocean, direct observations of nutrient distributions and the ecological importance of this phenomenon are still relatively scarce. In this context, we first describe a simple procedure to continuously sample nutrients in surface waters, and subsequently provide evidence of the existence of microscale distribution of ammonium in the ocean. We further show that ammonium is never homogeneously distributed, even under very high conditions of turbulence. Instead, turbulence intensity appears to control nutrient patchiness, with a more homogeneous or a more heterogeneous distribution observed under high and low turbulence intensities, respectively, under the same concentration in nutrient. Based on a modelling procedure taking into account the stochastic properties of intermittent nutrient distributions and observations carried out on natural phytoplankton communities, we introduce and verify the hypothesis that under nutrient limitation, the “turbulent history” of phytoplankton cells, i.e., the turbulent conditions they experienced in their natural environments, conditions their efficiency to uptake ephemeral inorganic nitrogen patches of different concentrations.
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- Date Issued: 2020
Probing the structural dynamics of the Plasmodium falciparum tunneling-fold enzyme 6-pyruvoyl tetrahydropterin synthase to reveal allosteric drug targeting sites:
- Authors: Khairallah, Afrah , Ross, Caroline J , Tastan Bishop, Özlem
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163057 , vital:41008 , https://doi.org/10.3389/fmolb.2020.575196
- Description: The de novo folate synthesis pathway is a well-established drug target in the treatment of many infectious diseases. Antimalarial antifolate drugs have proven to be effective against malaria, however, rapid drug resistance has emerged on the two primary targeted enzymes: dihydrofolate reductase and dihydroptoreate synthase. The need to identify alternative antifolate drugs and novel metabolic targets is of imminent importance. The 6-pyruvol tetrahydropterin synthase (PTPS) enzyme belongs to the tunneling fold protein superfamily which is characterized by a distinct central tunnel/cavity. The enzyme catalyzes the second reaction step of the parasite’s de novo folate synthesis pathway and is responsible for the conversion of 7,8-dihydroneopterin to 6-pyruvoyl-tetrahydropterin. In this study, we examine the structural dynamics of Plasmodium falciparum PTPS using the anisotropic network model, to elucidate the collective motions that drive the function of the enzyme and identify potential sites for allosteric modulation of its binding properties.
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- Date Issued: 2020
Protected and un-protected urban wetlands have similar aquatic macroinvertebrate communities: a case study from the Cape Flats Sand Fynbos region of southern Africa
- Authors: Blanckenberg, Michelle , Mlambo, Musa C , Parker, Denham , Motitsoe, Samuel N
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149288 , vital:38822 , https://0-doi.org.wam.seals.ac.za/10.1371/journal.pone.0233889
- Description: Rapid urbanisation has led to major landscape alterations, affecting aquatic ecosystems’ hydrological and biogeochemical cycles, and biodiversity. Thus, habitat alteration is considered a major driver of aquatic biodiversity loss and related aquatic ecosystem goods and services. This study aimed to investigate and compare aquatic macroinvertebrate richness, diversity and community structure between urban temporary wetlands, located within protected and un-protected areas. The latter were found within an open public space or park with no protection or conservation status, whereas the former were inaccessible to the public and had formal protected, conservation status.
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- Date Issued: 2020
The alternative theory of state-minded protest texts in the music of democratic Nigeria:
- Authors: Osiebe, Garhe
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160423 , vital:40444 , DOI: 10.1080/21681392.2020.1810085
- Description: This paper centres on an alternative discourse of popular music culture in re-democratized Nigeria. Whereas much work has been done on state-minded protest music in Nigeria, studies have been reticent in appreciating the works of Fela's son, Femi; particularly within a framework of re-democratized Nigeria's equivalent of Fela's works which constituted a major alternative voice through military-ruled Nigeria. The paper is an attempt to make up this lacuna along the lines of Chris Atton’s 2006 alternative media theory. The analysis of the alternative media theory is complemented by an analysis of the texts of selected state-minded protest works from two crossover popular musicians – Blackface and Mr Raw – of re-democratized Nigeria, both of whose state-minded protest works have hitherto been unexplored by the academe.
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- Date Issued: 2020
Tracing the Voice of Protest in Selected Oral Literature:
- Authors: Kaschula, Russell H
- Date: 2020
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/174452 , vital:42479 , ISBN 9783030555177
- Description: This chapter aims to present the notion of “protest” as a contested arena in the production of oral literature, against the backdrop of continued and contested sociopolitical change in Africa. This contestation can be politically based, gender based and sometimes even based in religion. The chapter looks specifically at poetry, songs and the folktale to establish how the “voice of protest” has been presented over time in relation to specific African countries such as Senegal, South Africa, Somali, Guinea, Kenya, Tanzania, Malawi, Ethiopia, Nigeria, Zimbabwe and Lesotho. Poetic protest as part of political protest is also discussed. Furthermore, the chapter seeks to explore how this “voice of protest” has been received, both from an audience point of view and from the point of view of those who control power.
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- Date Issued: 2020