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.
- Full Text:
- 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.
- Full Text:
- Date Issued: 2020
Rapid UPLC - MS/MS method for the determination of ketoprofen in human dermal microdialysis samples
- Authors: Tettey-Amlalo, Ralph N O , Kanfer, Isadore
- Date: 2009
- Language: English
- Type: text , Article
- Identifier: vital:6444 , http://hdl.handle.net/10962/d1006631
- Description: Dermal microdialysis (DMD) is a technique capable of determining the percutaneous penetration of drugs from topical formulations intended for local and/or regional activity. Typically, the concentrations of drug collected in dialysates are very low, generally in the ng/ml or even pg/ml range. An additional challenge is the very low volume of sample collected at each collection time and which can range from 1 to 30 μl only. Hence the objective was to develop and validate a rapid, accurate, precise, reproducible and highly sensitive LC–MS/MS method for the quantitative analysis of ketoprofen (KET) in dialystes following application of a topical gel product to the skin of human subjects. UPLC–MS/MS was used and KET was separated on an Acquity™ UPLC BEH C18 column (100 mm × 2.1 mm i.d., 1.7 μm) and analysed in negative-ion (NI) electrospray ionisation (ESI) mode. The mobile phase (MP) consisted of acetonitrile:methanol:water (60:20:20, v/v/v) under isocratic conditions at a flow rate of 0.3 ml/min. Samples were extracted using ethyl acetate with ibuprofen (IBU) as internal standard (IS) and the organic solvent was then evaporated to dryness and the residue re-constituted in methanol. 5 μl samples were injected and analysis was performed at ambient temperature 22 ± 0.5 °C. KET and IBU eluted at 1.07 and 1.49 min, respectively. KET and IBU responses were optimised at the transitions 253.00 > 209.00 and 205.00 > 161.00, respectively. Calibration curves were linear over the range 0.5–500 ng/ml with correlation coefficients > 0.999. The accuracy and precision of the method were found to be between 99.97% and 104.67% (R.S.D. < 2%) and the mean recovery of KET from normal saline was 88.03 ± 0.3% (R.S.D. < 2.20%). The LLOQ and LOD values were found to be 0.5 and 0.1 ng/ml respectively whereas the ULOD was set at 500 ng/ml. The method was successfully applied to determine the bioavailability of KET following application of topical KET gel, Fastum® gel, to the skin of human volunteers.
- Full Text:
- Date Issued: 2009
Repositioning Renaissance studies in South Africa: strategic thinking or 'business-as-usual
- Authors: Wright, Laurence
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7054 , http://hdl.handle.net/10962/d1007415
- Description: Increasingly, in many leading South African tertiary departments of literature, early modern studies have a fairly slim hold on the core curriculum. More and more, departmental offerings concentrate on nineteenth and twentieth century literature, perhaps in the belief either that today’s students are so poorly prepared that they will never be able to cope with the mental shifts necessary to appreciate pre-industrial literature and its language, or, worse, that nothing before the C19 colonial incursion into South Africa can really matter very much to undergraduates. Whatever the reason, in such departments, it is no longer possible to get to grips with the contribution of the renaissance to the formation of the modern world. The significance of the broader nomenclature, early modern studies, doesn’t appear to strike home, especially the point that, if students want to understand the world we live in, they have to know this period particularly well. Indeed, they need to have some idea of the interaction between early modern Europe and the literature and ideas of the ancient civilizations of Rome and Greece. If we fail them in this regard, as I believe we are doing to an increasing extent, the result will be generations of intellectual sleepwalkers, denizens of mental landscapes they are responding to, or ‘reading’, in terms of an inner life unaware of important historical continuities and disjunctions; cut off, moreover, from understanding essential features of modernity.
- Full Text:
- Date Issued: 2006
Reviews: Unsettling Questions: Palestine, Israel, the Holy Land and Zion
- Authors: Stähler, A , Vice, S , Brauner, D , Bassi, S , Naidu, Samantha , King, B , O'Neal, G S , Aldama, F L , Gibbs, J , Rotstein, J R U , Calderaro, M A
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157948 , vital:40133 , https://doi.org/10.1080/02690050802589479
- Description: Reviews: Unsettling Questions: Palestine, Israel, the Holy Land and Zion
- Full Text:
- Date Issued: 2009
Rhodes 1985 - 95
- Authors: Henderson, Derek Scott
- Date: 1985
- Language: English
- Type: text
- Identifier: vital:7505 , http://hdl.handle.net/10962/d1018382
- Full Text:
- Date Issued: 1985
Rhodes University Graduation Ceremony 1976
- Authors: Rhodes University
- Date: 1976
- Language: English
- Type: text
- Identifier: vital:8110 , http://hdl.handle.net/10962/d1004565
- Description: Rhodes University Graduation Ceremonies on Friday 9th April 1976 at 8 p.m. [and] on Saturday 10th April 1976 at 10:30 a.m.in the University Great Hall.
- Full Text:
- Date Issued: 1976
Rural self-reliance strategies in South Africa : community initiatives and external support in the former black homelands
- Authors: Nel, Etienne L , Binns, Tony
- Date: 2000
- Language: English
- Type: Article
- Identifier: vital:6716 , http://hdl.handle.net/10962/d1006789
- Description: This paper examines the relevance of the concept of self-reliance in the context of rural community economic development in South Africa. Whilst changing global and local circumstances oblige impoverished communities to become more pro-active in the enhancement of the quality of their lives, they nevertheless cannot ignore basic market forces and the need for an appropriate level of external assistance. Four community-based agricultural ventures in South Africa's former Homelands are examined. A comparison between the four schemes permits an assessment to be made of what such community ventures require if they are to succeed and have a meaningful impact on job creation and poverty alleviation. The role of external support agencies and access to markets in each case features prominently in the assessment.
- Full Text:
- Date Issued: 2000
SACCAWU - NSSC Secretariat Report & Bargaining conference resolutions
- Authors: SACCAWU
- Date: Oct 2007
- Subjects: SACCAWU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/113902 , vital:33843
- Description: Comrades National Office Bearers of SACCAWU, leadership of the Company Council, distinguished guests & delegates to this Summit, we extend to you revolutionary greetings from the National Office Bearers of Shoprite Checkers, and the masses of Shoprite Checkers workers who are SACCAWU members. This gathering takes place exactly a year after our national strike. It also takes place after lot of significant gatherings of all the Alliance Partners i.e. COSATU Central Committee, SACP National Conference, ANC National Policy Conference, and on the home front, the SACCAWU National Bargaining Conference. It is the important that the deliberations in this gathering should look at all decisions taken during this significant event, the Bargaining Conference, and put them into practicality. This Secretariat Report will cover the activities since the National Shopstewards Council of June 2006 in Durban.
- Full Text:
- Date Issued: Oct 2007
SADTU standard terms and conditions of employment
- Authors: SADTU
- Date: Apr 1999
- Subjects: SADTU
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/118008 , vital:34584
- Description: These terms and conditions of employment govern the employment of all permanent employees at the South African Democratic Teachers' Union (SADTU). These standard terms and conditions do not apply to temporary, part- time or fixed-term contract employees.
- Full Text:
- Date Issued: Apr 1999
Shifting white identities in South Africa: white Africanness and the struggle for racial justice
- Authors: Matthews, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142180 , vital:38056 , DOI: 10.25159/2413-3086/3821
- Description: The end of apartheid predictably caused something of an identity crisis for white South Africans. The sense of uncertainty about what it means to be white has led to much public debate about whiteness in South Africa, as well as a growing body of literature on whites in post-apartheid South Africa. One of the many responses to this need to rethink white identity has been the claim by some that white South Africans can be considered to be African or ought to begin to think of themselves as being African. This paper argues that whites' assertion of an African identity does not necessarily assist in the achievement of racial justice, but that some kind of shift in white identity is required in order for whites to be able to contribute to the achievement of a racially just South Africa. In making this argument, the paper brings contemporary discussions on race and whiteness, and in particular discussions about racial eliminativism, to bear on the question of whether or not white South Africans may rightly claim an African identity.
- Full Text:
- Date Issued: 2015
Social parasitism by honeybee workers (Apis mellifera capensis Escholtz): host finding and resistance of hybrid host colonies
- Authors: Neumann, Peter , Radloff, Sarah E , Moritz, Robin F A , Hepburn, H Randall , Reece, Sacha L
- Date: 2001
- Language: English
- Type: text , Article
- Identifier: vital:6907 , http://hdl.handle.net/10962/d1011860
- Description: We studied possible host finding and resistance mechanisms of host colonies in the context of social parasitism by Cape honeybee (Apis mellifera capensis) workers. Workers often join neighboring colonies by drifting, but long-range drifting (dispersal) to colonies far away from the maternal nests also rarely occurs. We tested the impact of queenstate and taxon of mother and host colonies on drifting and dispersing of workers and on the hosting of these workers in A. m. capensis, A. m. scutellata, and their natural hybrids. Workers were paint-marked according to colony and reintroduced into their queenright or queenless mother colonies. After 10 days, 579 out of 12,034 labeled workers were recaptured in foreign colonies. We found that drifting and dispersing represent different behaviors, which were differently affected by taxon and queenstate of both mother and host colonies. Hybrid workers drifted more often than A. m. capensis and A. m. scutellata. However, A. m. capensis workers dispersed more often than A. m. scutellata and the hybrids combined, and A. m. scutellata workers also dispersed more frequently than the hybrids. Dispersers from queenright A. m. capensis colonies were more often found in queenless host colonies and vice versa, indicating active host searching and/or a queenstate-discriminating guarding mechanism. Our data show that A. m. capensis workers disperse significantly more often than other races of A. mellifera, suggesting that dispersing represents a host finding mechanism. The lack of dispersal in hybrids and different hosting mechanisms of foreign workers by hybrid colonies may also be responsible for the stability of the natural hybrid zone between A. m. capensis and A. m. scutellata.
- Full Text:
- Date Issued: 2001
Sport consumption patterns in the Eastern Cape: cricket spectators as sporting univores or omnivores
- Authors: Brock, Kelcey , Fraser, Gavin C G , Botha, Ferdi
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69362 , vital:29508 , https://doi.org/10.4102/jef.v9i3.64
- Description: Since its inception, consumption behaviour theory has developed to account for the important social aspects that underpin or at least to some extent explain consumer behaviour. Empirical studies on consumption behaviour of cultural activities, entertainment and sport have used Bourdieu’s (1984) omnivore/univore theory to investigate consumption of leisure activities. The aim of this study is to investigate whether South African cricket spectators are sporting omnivores or univores. The study was conducted among cricket spectators in the Eastern Cape at four limited overs cricket matches in the 2012/2013 cricket season. The results indicate that consumption behaviour of sport predominantly differs on the grounds of education and race. This suggests that there are aspects of social connotations underpinning sports consumption behaviour within South Africa.
- Full Text:
- Date Issued: 2016
Stronger induction of callose deposition in barley by Russian wheat aphid than bird cherry-oat aphid is not associated with differences in callose synthase or ≤-1,3-glucanase expression
- Authors: Saheed, Sefiu A , Cierlik, Izabela , Larsson, Kristina A E , Delp, Gabriele , Bradley, Graeme , Jonsson, Lisbeth M V , Botha, Christiaan E J
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6542 , http://hdl.handle.net/10962/d1005984
- Description: The effects of infestation by the bird cherry-oat aphid (BCA), (Rhopalosiphum padi L) and the Russian wheat aphid (RWA) (Diuraphis noxia Mordvilko) on callose deposition and gene expression related to callose accumulation were investigated in barley (Hordeum vulgare L. cv. Clipper). The BCA, which gives no visible symptoms, induced very limited callose deposition, even after 14 days of infestation. In contrast, RWA, which causes chlorosis, white and yellow streaking and leaf rolling, induced callose accumulation already after 24h in longitudinal leaf veins. The deposition was pronounced after 72 h, progressing during 7 and 14 days of infestation. In RWA-infested source leaves, callose was also induced in longitudinal veins basipetal to the aphid-infested tissue, whereas in sink leaves, more callose deposition was found above the feeding sites. Nine putative callose synthase genes were identified in a data base search, of which eight were expressed in the leaves, but with similar level of expression in control and aphid-infested tissue. Four out of 12 examined β-1,3-glucanases were expressed in the leaves, and three of them were up-regulated in aphid-infested tissue. They were all more strongly induced by RWA than BCA. The results suggest that callose accumulation may be partly responsible for the symptoms resulting from RWA feeding and that a callose-inducing signal may be transported in the phloem. Furthermore it is concluded that the absence of callose deposition in BCA-infested leaves is not due to a stronger induction of callose-degrading β-1,3-glucanases in this tissue, as compared to RWA-infested leaves.
- Full Text:
- Date Issued: 2009
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.
- Full Text:
- Date Issued: 2020
The concentrations of the noble metals in Southern African flood-type basalts and MORB: implications for petrogenesis and magmatic sulphide exploration
- Authors: Maier, Wolfgand D , Barnes, Sarah-Jane , Marsh, Julian S
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150573 , vital:38985 , https://doi.org/10.1007/s00410-003-0480-z
- Description: Concentrations of the platinum-group elements have been determined in several suites of southern African flood-type basalts and mid-ocean ridge basalt (MORB), covering some 3 Ga of geologic evolution and including the Etendeka, Karoo, Soutpansberg, Machadodorp, Hekpoort, Ventersdorp and Dominion magmas.
- Full Text: false
- Date Issued: 2003
The deployment of the medico-psychological gaze and disability expertise in relation to children with intellectual disability
- Authors: Mckenzie, Judith A , Macleod, Catriona I
- Date: 2012
- Language: English
- Type: Article
- Identifier: vital:6294 , http://hdl.handle.net/10962/d1014732 , http://www.tandfonline.com/doi/full/10.1080/13603116.2010.540042
- Description: In this study, we adopt the concepts of Michel Foucault on the medical gaze and Nikolas Rose on psychological expertise to differentiate between two forms of expertise evident in the education of intellectually disabled children. We draw on a discourse analytic study carried out in South Africa on intellectual disability in relation to educational practice to examine the operation of a medico-psychological gaze that calls for disability expertise in the management of disability. We conclude our discussion by noting that the dichotomy between impairment and disability that is proposed in the social model of disability does little to destabilise the power of the medico-psychological gaze since impairment is conceded to biomedical knowledge as an object of positive knowledge. This tacit acceptance of the medical authority gives sanction to disability expertise that operates in diffuse ways to regulate the educational experience of learners with intellectual disability. The implications of this conception for inclusive education are briefly explored, and further areas for research are suggested.
- Full Text:
- Date Issued: 2012
The Edeucational Journal
- Date: 1983-05
- Subjects: Education –- South Africa , South Africa -- Politics and government , Government, Resistance to -- South Africa
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/36016 , vital:33881 , Bulk File 7
- Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa.
- Full Text: false
- Date Issued: 1983-05
The Educational Journal
- Date: 1985-11
- Subjects: Education –- South Africa , South Africa -- Politics and government , Government, Resistance to -- South Africa
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/37161 , vital:34132 , Bulk File 7
- Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa.
- Full Text: false
- Date Issued: 1985-11
The Educational Journal
- Date: 1984-02
- Subjects: Education –- South Africa , South Africa -- Politics and government , Government, Resistance to -- South Africa
- Language: English
- Type: text , Article
- Identifier: http://hdl.handle.net/10948/36594 , vital:34021 , Bulk File 7
- Description: The Educational Journal was the official organ of the Teachers' League of South Africa and focussed on education within the context of a racialized South Africa.
- Full Text: false
- Date Issued: 1984-02