WIReDSpace
Welcome to WIReDSpace (Wits Institutional Repository on DSpace)
For queries relating to content and technical issues, please contact IR specialists via this email address : openscholarship.library@wits.ac.za,
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Communities in WIReDSpace
Select a community to browse its collections.
- This community is for all faculties and schools' research outputs by Wits academics and researchers
- This community hosts traditional outputs such as published and unpublished research articles, conference papers, book chapters and other research outputs authored by Wits academics and researchers. Items in this collection are also mapped to relevant collections within the Faculties/Schools/Departments communities for more specific browsing and searching.
- This community is for all faculties and schools' electronic theses and dissertations (ETDs) by masters and doctoral students. NB: All electronic theses and dissertations to be edited and moved/uploaded here.
- This community for all Wits Inaugural lectures.
- This community is for all Wits Libraries staff presentations and publications.
Recent Submissions
Item type:Item, DRTBHDT a randomized controlled trial of two adjunctive hostdirected therapies in rifampinresistant tuberculosisNestani Tukvadze; Sehlomola Mashatole; Anne Jacobs; Tlhago Ngwanto; Pauline Howell; E et alItem type:Item, Delpazolid in combination with bedaquiline delamanid and moxifloxacin for pulmonary tuberculosis PanACEADECODE01 a prospective randomised openlabel phase 2b dosefinding trialLilian Tina Minja; Isabella van der Feltz; C Manyama; S Mpagama; Mohammed RassoolItem type:Item, Estimation of therapeutic threshold for tuberculosis using adapted nominal group technique and clinical vignettes in clinical and community settings in Southern AfricaAlfred Kipyegon Keter; Alastair Van Heerden; Tom Decroo; Tom Boyles; Shannon Bosman; T Madonsela; E et al.Item type:Item, Development of a Cryopreservation Protocol for In Vitro Buds of South African Sweet Potato Accessions(University of the Witwatersrand, Johannesburg, 2025-06) Manamela, Machoene Tshidi; Glennon, Kelsey I.Cryopreservation improves and strengthens the conservation of sweet potato (Ipomoea batatas) accessions conserved in the field gene bank and tissue culture at the South African National Plant Genetic Resources Centre (NPGRC). Cryopreservation is usually achieved at -196°C in liquid nitrogen (LN) in which the metabolic functions of the material are halted. Field gene bank and tissue culture conservation methods are used for short to medium term conservation. Cryopreservation approaches need to be developed to effectively conserve sweet potato for long-term conservation because currently, there are no long-term conservation methods used. The encapsulation-vitrification method using plant vitrification solution 2 (PVS2) is generally used for crop species, but the success varies depending on the cultivar. In this regard, modifications were needed to obtain successful cryopreservation of the sweet potato accessions of the South African NPGRC. It was believed that the encapsulation-vitrification method using PVS2 as a cryoprotectant would result in a higher percentage of regeneration compared with other cryopreservation methods. This study aimed to assess the buds’ viability, water content and optimise the concentration and duration of exposure to cryoprotectants for successful cryopreservation, using the encapsulation-vitrification method. The use of PVS2 resulted in no plant regeneration after retrieval from liquid nitrogen (LN) suggesting that it may have been toxic to these accessions. Therefore, it was important to understand the impact of the individual and combination components of PVS2 on the viability of the buds of sweet potato. The suitable concentration of combination components of PVS2 was PVS5% which resulted in 93% regeneration. However, the materials did not survive the cooling and rewarming processes indicating too higher water content to survive cooling and rewarming. After treatment with preincubation, preculture, osmoprotection and PVS5% increased the water content from 26 to 72%. Swapping PVS5% with osmoprotection solution reduced the water content to 34%, but the regeneration was negatively impacted. Reducing exposure to the osmoprotection solution to 20 minutes resulted in 70–80% regeneration but did not provide sufficient dehydration for successful cryopreservation. Modified Plant vitrification solution 3 (70%PVS3) applied sequentially with PVS5%, osmoprotection solution and physical dehydration, retained the regeneration rate (83–87%) and no crystallisation during cooling in LN. Recrystallisation occurred only during rewarming process in 1.2 M sucrose at 38-40°C. The combination treatment (PVS-PD) applied in this study exhibited potential in sweet potato cryopreservation and warrants further investigation to refine the rewarming technique following cryopreservation.Item type:Item, 24week alloral regimens for pulmonary rifampicinresistant tuberculosis in TBPRACTECAL trial sites an economic evaluationS Sweeney; Yoko V Laurence; C Berry; Maninder Pal Singh; Mohammed Rassool; E et al