Invaded habitat incompatibility affects the suitability of the potential biological control agent Listronotus sordidus for Sagittaria platyphylla in South Africa
- Authors: Martin, Grant D , Coetzee, Julie A , Lloyd, Melissa , Nombewu, Sinoxolo E , Ndlovu, Mpilonhle S , Kwong, Raelene M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103926 , vital:32323 , https://doi.org/10.1080/09583157.2018.1460314
- Description: Sagittaria platyphylla (Engelmann) J.G. Smith (Alismataceae) was first recorded in South Africa in 2008 and is considered to be an emerging weed with naturalised populations occurring throughout the country. A biological control programme was initiated in Australia and surveys conducted between 2010 and 2012 yielded potential agents, including the crown feeding weevil, Listronotus sordidus Gyllenhal (Coleoptera: Curculionidae). The potential of L. sordidus as a candidate biological control agent against S. platyphylla in South Africa was examined. Although adult feeding was recorded on a number of plant species, oviposition and larval development indicated a narrow host range restricted to the Alismataceae. In South Africa, S. platyphylla populations are primarily found in inundated systems. However, laboratory studies showed that L. sordidus did not oviposit on inundated plants, potentially nullifying the impact of the insect on South African populations. It is suggested that even though L. sordidus is a damaging, specific agent, its limited impact on inundated plant populations in South Africa does not justify the inherent risk associated with the release of a biological control agent.
- Full Text: false
- Date Issued: 2018
Investigating a new wealth tax in South Africa: Lessons from international experience
- Authors: Arendse, Jacqueline A , Stack, Elizabeth M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69434 , vital:29536 , https://jefjournal.org.za/index.php/jef/article/view/175/193
- Description: In recent years, there has been an increasing focus on new sources of taxation, including wealth tax. In South Africa, two phenomena have driven the focus on wealth tax. Firstly, the need for additional tax revenue to fund an ongoing and growing budget deficit, exacerbated by a prolonged period of low economic growth, rising government debt and a very small base of individual taxpayers. Secondly, the fact that South Africa has one of the most unequal societies in the world. The dual demands of increased tax revenue and economic inequality have converged around wealth tax as a possible panacea to both problems. Although South Africa has a long history of wealth transfer tax in the form of estate duty and donations tax, there has never been a tax on the net wealth holdings of individuals during their lifetime. Internationally, numerous countries have used wealth tax in various forms, including inheritance tax, gift tax, recurrent wealth tax and non-recurrent wealth tax. This study examines some of the international experiences with these three categories of wealth tax, seeking lessons and experiences that can inform the debate around the viability of a new wealth tax in South Africa.
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- Date Issued: 2018
Isolation and Characterisation of Stigmasterol and β–Sitosterol from Anthocleista djalonensis A. Chev.
- Authors: Okoro, Ijeoma S , Tor-Anyiin, Terrumun A , Igoli, John O , Noundou, Xavier S , Krause, Rui W M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126191 , vital:35857 , https://doi.org/10.9734/AJOCS/2017/37147
- Description: Aim: Anthocleista djalonensis A. Chev. is a plant with several chemical constituents whichaccounts for its ethno-pharmacological uses. The present study is aimed at identifying and characterizing the active principles from the roots of the plant. Place and Duration of Study: The study was carried out at the Department of Organic Chemistry,Rhodes University, Grahamstown, South Africa between March and July 2016. Methodology: The root powder was subjected to maceration with methanol to obtain the crude extract. The methanol extract was fractionated using hexane, ethyl acetate and acetone successively. The acetone extract was thereafter subjected to column chromatography to isolate any pure components. Results: White needle-like crystals were obtained which on spectral analysis(IR, 1H NMR, 13C NMR, 2D- NMR, and ESI-MS ) were identified as a mixture of stigmasterol and β-sitosterol. Conclusion: The compounds isolated were identified as stigmasterol and β-sitosterol.
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- Date Issued: 2018
Jesus, Che, Luaty: on the relationship between a digital picture and an iconic image in political iconography in Angola
- Authors: Siegert, Nadine
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145919 , vital:38478 , DOI: 10.2979/africatoday.65.1.04
- Description: This essay makes a close examination of a selection of images of the Angolan rapper Luaty Beirão, who became internationally known as a political activist during his imprisonment in June 2015, accused of staging a coup d'état. By analyzing and interpreting images that were highly mediatized during that period, this article shows how political iconography can be traced back to Christian iconography and other images. Such filiations of images and their mediatization invoke a power that contributes to the formation of political and popular icons. This article analyzes this nexus by deconstructing the transmutation of a photograph into a popular icon.
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- Date Issued: 2018
Kowieria alveoformis gen. nov. sp. nov., a new heterosporous lycophyte from the Latest Devonian of Southern Africa
- Authors: Gess, Robert W , Prestianni, Cyrille
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/73894 , vital:30239 , https://doi.org/10.1016/j.revpalbo.2017.10.002
- Description: A new lycopsid, Kowieria alveoformis gen. et sp. nov., is described from the FamennianWitpoort Formation, Grahamstown, South Africa. It possesses spirally arranged elongated falcate vegetative leaves. Terminal bisporangiate strobili are present and show loosely grouped micro- and megasporophylls. Sporophylls are similar in shape to the vegetative leaves though somewhat wider with a marked expansion to house the sporangium. One sporangium is attached directly to the adaxial surface of the lamina. Each megasporangium contains up to four heavily ornamented hologulate megaspores of the Lagenicula type. The combination of both basal and derived characters within this plant places it at an interesting position at the base of the phylogenetic tree of rhizomorphic lycopsids.
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- Date Issued: 2018
Largest reported groups for the Indo-Pacific bottlenose dolphin (Tursiops aduncus) found in Algoa Bay, South Africa: trends and potential drivers
- Authors: Bouveroux, Thibaut N , Caputo, Michelle , Froneman, P William , Plön, Stephanie
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67913 , vital:29168 , https://doi.org/10.1111/mms.12471
- Description: Publisher version , This study investigates how group size of Indo‐Pacific bottlenose dolphins (Tursiops aduncus) changes temporally, spatially, and/or with predominant behavior at two discreet sites along the Eastern Cape coastline of South Africa: Algoa Bay and the Wild Coast. The mean group size of bottlenose dolphins was large with an average of 52 animals. Significantly larger groups were observed in Algoa Bay ( = 60, range = 1–600) than off the Wild Coast ( = 32.9, range = 1–250). In Algoa Bay, the mean group size increased significantly over the study period, from an average 18 animals in 2008 to 76 animals in 2016. Additionally, the largest average and maximum group sizes ever reported both in South Africa and worldwide, were recorded in Algoa Bay (maximum group size = 600). Neither season nor behavior had a significant effect on mean group size at both sites. Similarly environmental variables such as the depth and substrate type also had no influence on group size. It remains unclear which ecological drivers, such as predation risk and food availability, are leading to the large groups observed in this area, and further research on abundance and distribution of both predators and prey is necessary.
- Full Text: false
- Date Issued: 2018
Legitimation of knowers for access in science
- Authors: Ellery, Karen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70302 , vital:29643 , https://doi.org/10.1080/02602930701772788
- Description: Based on poor performance of students in the higher education science context, this paper questions the current focus on content knowledge and, in so doing, examines the role student knowers play in enabling epistemological access. Using Legitimation Code Theory, and drawing on data from interviews, course documents, observations, and critical reflections, the social relations of a science foundation course in the South African context are examined empirically to reveal the valuing of two kinds of knowers—learning-context knowers (or science learners) and production-context knowers (or scientists). Since being both kinds of knowers is necessary for access to powerful science knowledge, and home and educational contexts of certain groups of students are better in terms of enabling science knowers and learners than others, it is argued from a social justice perspective that science (and other) curricula account for knower attributes in enabling access for success for all students.
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- Date Issued: 2018
Limitations of the random response technique and a call to implement the ballot box method for estimating recreational angler compliance using surveys:
- Authors: Bova, Christopher S , Aswani, Shankar , Farthing, Matthew W , Potts, Warren M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145359 , vital:38431 , DOI: 10.1016/j.fishres.2018.06.017
- Description: Accurate estimation of the levels of non-compliance to fishing regulations is crucial in ensuring that long term sustainability goals of fisheries are met. When requesting information regarding sensitive behaviour, such as an angler’s non-compliance to regulations through direct questioning methods (DQM), their responses can be influenced by social desirability bias (SDB). Literature in human dimensions research on methods for controlling this bias is limited. There has been an emerging prevalence in the use of the random response technique (RRT), which is a method aimed at reducing SDB in questions regarding sensitive behaviour, although it has never been validated against observed data in an environmental resource use context. An alternative to the RRT, the use of a ballot box method (BBM) has been successfully implemented to reduce SDB in contingent valuation studies and is introduced in this paper as a method for reducing SDB in face-to-face survey responses regarding sensitive behaviour.
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- Date Issued: 2018
Literary cynics: Borges, Beckett, Coetzee
- Authors: Marais, Mike
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144148 , vital:38315 , DOI: 10.1080/17533171.2018.1427849
- Description: Samuel Beckett’s last few plays were all written by invitation and performed before specialist audiences who were familiar with his work and knew what they could expect from him. Arthur Rose quite rightly points out that such expectation is constitutive in nature, that these audiences approached the plays with the baggage of a “preconceived Beckett” (112–13). He is also right when he argues that Beckett, in the plays in question, evinces an awareness of his reification as an author and of the authority of reputation.
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- Date Issued: 2018
Local perceptions of environmental changes in fishing communities of southwest Madagascar:
- Authors: Lemahieu, Anne , Scott, Lucy E P , Malherbe, Willem , Mahatante, Paubert T , Randrianarimanana, José V , Aswani, Shankar
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145370 , vital:38432 , DOI: 10.1016/j.ocecoaman.2018.06.012
- Description: Southwest Madagascar is a region that is significantly impacted upon by climate change. As in a lot of developing countries, the livelihoods of many communities in this region are dependent on fishing. This makes these communities particularly vulnerable to climate-related changes. We conducted a survey in two coastal fishing communities in the Toliara Province, Ambola and Ambotsibotsike. Using a free listing exercise, semi-structured interviews and focus group methods, we documented local perceptions of environmental changes and responses to changes. Results were compared, taking into account the differences in the degree of remoteness, market exposure and religiosity. Time periods that respondents reported as having had a high degree of change were compared to time periods of historical records of cyclones occurring in Toliara Province.
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- Date Issued: 2018
Low symmetric metallophthalocyanine modified electrode via click chemistry for simultaneous detection of heavy metals
- Authors: Fomo, Gertrude , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187914 , vital:44709 , xlink:href="https://doi.org/10.1016/j.jelechem.2018.02.016"
- Description: Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory.
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- Date Issued: 2018
LRP1 is required for novobiocin-mediated fibronectin turnover:
- Authors: Boel, Natasha M-E , Hunter, Morgan C , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164896 , vital:41182 , DOI: 10.1038/s41598-018-29531-2
- Description: Fibronectin (FN) plays a major role in the stability and organization of the extracellular matrix (ECM). We have previously demonstrated that FN interacts directly with Hsp90, as well as showing that the Hsp90 inhibitor novobiocin results in FN turnover via a receptor mediated process. However, the receptor involved has not been previously identified. LRP1 is a ubiquitous receptor responsible for the internalisation of numerous ligands that binds both Hsp90 and FN, and therefore we investigated whether LRP1 was involved in novobiocin-mediated FN turnover.
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- Date Issued: 2018
Major security incidents since 2014: an African perspective
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
- Full Text: false
- Date Issued: 2018
Mapping the field of Higher Education Research using PhD examination reports
- Authors: McKenna, Sioux , Quinn, Lynn , Vorster, Jo-Anne
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66669 , vital:28979 , ISSN 1469-8366 , https://doi.org/10.1080/07294360.2018.1428178
- Description: Pre-print , The PhD is the highest formal qualification and signifies a scholar’s rite of passage as a legitimate contributor of new knowledge in a field. Examiner reports make claims about what is legitimate in a thesis and what is not and thus articulate the organising principles through which participation in a field is measured. The authors analysed 39 examiners’ reports on 13 PhDs produced over a five-year period by scholars from the Higher Education Research doctoral studies programme at Rhodes University in South Africa. Drawing on aspects of Karl Maton’s Legitimation Code Theory (LCT), this study uses the dimensions of LCT:Specialisation and LCT:Semantics to explore what kinds of knowledge, skills and procedures and what kinds of knowers are validated in the field of Higher Education Research through the examination process. The study found that despite concerns in the literature about the a-theoretical nature of the Higher Education Studies field, examiners valued high-level theoretical and meta-theoretical engagement as well as methodological rigour. In addition, examiners prized the ability to demonstrate a strong ideological position, to use a clear doctoral voice, and to recognise the axiological drive of the field. The analysis showed that examiners were interested in strong contextualisation of the problem-spaces in higher education in South Africa but also commented positively on candidates’ ability to move from troubling an issue within its context to being able to abstract findings so as to contribute to the field as a whole.
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- Date Issued: 2018
Marine resource management and conservation in the Anthropocene
- Authors: Aswani, Shankar , Basurto, Xavier , Ferse, Sebastian , Glaser, Marion , Campbell, Lisa , Cinner, Joshua E , Dalton, Tracey , Jenkins, Lekelia D , Miller, Marc L , Pollnac, Richard , McGill University , Christie, Patrick
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124987 , vital:35716 , https://doi.10.1017/S0376892917000431
- Description: Because the Anthropocene by definition is an epoch during which environmental change is largely anthropogenic and driven by social, economic, psychological and political forces, environmental social scientists can effectively analyse human behaviour and knowledge systems in this context. In this subject review, we summarize key ways in which the environmental social sciences can better inform fisheries management policy and practice and marine conservation in the Anthropocene. We argue that environmental social scientists are particularly well positioned to synergize research to fill the gaps between: (1) local behaviours/needs/worldviews and marine resource management and biological conservation concerns; and (2) large-scale drivers of planetary environmental change (globalization, affluence, technological change, etc.) and local cognitive, socioeconomic, cultural and historical processes that shape human behaviour in the marine environment. To illustrate this, we synthesize the roles of various environmental social science disciplines in better understanding the interaction between humans and tropical marine ecosystems in developing nations where issues arising from human–coastal interactions are particularly pronounced. We focus on: (1) the application of the environmental social sciences in marine resource management and conservation; (2) the development of ‘new’ socially equitable marine conservation; (3) repopulating the seascape; (4) incorporating multi-scale dynamics of marine social–ecological systems; and (5) envisioning the future of marine resource management and conservation for producing policies and projects for comprehensive and successful resource management and conservation in the Anthropocene.
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- Date Issued: 2018
Mbeki's African Renaissance Vision as Reflected in isiXhosa Written Poetry: 2005–2011
- Authors: Mona, Godfrey V , Kaschula, Russell H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174705 , vital:42502 , ttps://doi.org/10.1080/18186874.2018.1457616
- Description: IsiXhosa literary critics have not yet interrogated literature that was produced during and after the tenure of Thabo Mvuyelwa Mbeki as deputy president and president of the Republic of South Africa in order to study the impact of his African Renaissance doctrine. This article analyses poetry that was produced from 2005 to 2011. The content of the isiXhosa written poetry is profoundly influenced by the context of former President Mbeki's African Renaissance philosophy, its implementation structures and philosophy of self-confidence and self-reliance. The selected poems analysed and interpreted in this article suggest that Mbeki's legacy of the African Renaissance empowered poets to develop a narrative that advances the building of a regenerated South African nation and the African continent.
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- Date Issued: 2018
Mechanisms and indicators for assessing the impact of biofuel feedstock production on ecosystem services
- Authors: Gasparatos, Alexandros , Romeu-Dalmau, Carla , von Maltitz, Graham P , Johnson, Francis X , Shackleton, Charlie M , Jarzebski, Marcin P , Jumbe, Charles , Ochieng, Caroline , Mudombi, Shakespear , Nyambane, Anne , Willis, Katherine J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181368 , vital:43727 , xlink:href="https://doi.org/10.1016/j.biombioe.2018.01.024"
- Description: Biofuel feedstock production can be a significant driver of landscape modification, ecosystem change and biodiversity loss. There is growing body of literature that shows how biofuel landscapes provide various ecosystem services (e.g., feedstock for fuel, carbon sequestration) and compromise other ecosystem services (e.g., food, freshwater services). These effects are context-specific and depend largely on prior land use conditions and feedstock production practices. Changes in the flow of ecosystem services due to the conversion of natural and agricultural areas can have ripple effects on human wellbeing. Despite some recent attempts to apply to biofuel settings concepts and methods rooted in the ecosystem services literature, this is the exception rather than the rule within both the biofuel and the ecosystem services research communities. This paper synthesizes the current knowledge about the impact of biofuels on ecosystem services. It focuses especially on the feedstock production phase and outlines the main mechanisms through which landscape conversion affects the provisions of ecosystem services. It proposes conceptually coherent indicators to reflect these mechanisms and offers a critical discussion of key issues at the interface of biofuels and ecosystem services.
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- Date Issued: 2018
Metabolic activity throughout early development of dusky kob Argyrosomus japonicus (Sciaenidae)
- Authors: Edworthy, Carla , James, Nicola C , Erasmus, B , Kemp, J O G , Kaiser, Horst , Potts, Warren M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125159 , vital:35737 , https://doi.10.2989/1814232x.2018.1441907
- Description: Metabolism quantifies the energy-consuming activities of an organism (Nelson 2016) and is used as an indication of how organisms partition energy resources to activities that allow them to survive, grow and reproduce (Post and Lee 1996). The metabolic profile, which is a composition of the various metabolic rates of an individual, therefore gives an indication of the efficiency of energy transformation and allocation (Fry 1971; Brown et al. 2004). McKenzie et al. (2016) suggested that an organism’s physiology contributes towards its ability to survive under specific environmental conditions. As a result, physiological condition can be a reflection of the performance and fitness of an organism (Pörtner 2010). When combined with information on changing environmental conditions, physiological information can provide insight into species- and community-level responses (Pörtner and Farrell 2008). These kinds of data have served numerous ecological applications, including resource management, conservation (McKenzie et al. 2016) and climate-change assessments (Pörtner and Farrell 2008).
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- Date Issued: 2018
MODE-TASK: Large-scale protein motion tools
- Authors: Ross, Caroline J , Nizami, B , Glenister, M , Amamuddy, Olivier S , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125206 , vital:35746 , http://dx.doi.org/10.1101/217505
- Description: Conventional analysis of molecular dynamics (MD) trajectories may not identify global motions of macromolecules. Normal Mode Analysis (NMA) and Principle Component Analysis (PCA) are two popular methods to quantify large-scale motions, and find the “essential motions”; and have been applied to problems such as drug resistant mutations (Nizami et al., 2016) and viral capsid expansion (Hsieh et al., 2016). MODE-TASK is an array of tools to analyse and compare protein dynamics obtained from MD simulations and/or coarse grained elastic network models. Users may perform standard PCA, kernel and incremental PCA (IPCA). Data reduction techniques (Multidimensional Scaling (MDS) and t-Distributed Stochastics Neighbor Embedding (t-SNE)) are implemented. Users may analyse normal modes by constructing elastic network models (ENMs) of a protein complex. A novel coarse graining approach extends its application to large biological assemblies.
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- Date Issued: 2018
Modulation of human Hsp90α conformational dynamics by allosteric ligand interaction at the c-terminal domain:
- Authors: Penkler, David L , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148402 , vital:38736 , DOI: 10.1101/386755
- Description: Recent years have seen heat shock protein 90 kDa (Hsp90) attract significant interest as a viable drug target, particularly for cancer. To date, designed inhibitors that target the ATPase domain demonstrate potent anti-proliferative effects, but have failed clinical trials due to high levels of associated toxicity. To circumvent this, the focus has shifted away from the ATPase domain. One option involves modulation of the protein through allosteric activation/inhibition. Here, we propose a novel approach: we use previously obtained information via residue perturbation scanning coupled with dynamic residue network analysis to identify allosteric drug targeting sites for inhibitor docking.
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- Date Issued: 2018