The characterization of DNAJC3: elucidating the function of the TPR domains

DNAJC3 is a novel member of the DNAJ family with two domains linked to co-chaperone functions, namely the tetratricopeptide repeat (TPR) and J domain. Out of the two domains, the TPR domains are the least characterized. Therefore, the aim of this study was to characterize and elucidate additional functions of DNAJC3 TPR domains through in silico, in vitro and ex vivo approaches. Through multiple sequence and structural alignment as well as electrostatic potential analysis, DNAJC3 TPR domain were found to be most similar to TPR-containing proteins with Hsp90 or Hsp70 independent functions. In vitro pull down assays illustrated that DNAJC3 TPR domains did not interact with either cytosolic Hsp90 and Hsp70 or Grp78 and Grp94 directly, however a potential indirect interaction with Grp94 and Hsp90 was observed in mammalian lysates, via pull down assays; suggesting the formation of a complex between the proteins mediated by a specific substrate. DNAJC3 TPR domains were found to bind indiscriminately to both native and heat denatured substrates in a dose dependent manner. DNAJC3 TPR domains bound to β-galactosidase with greater affinity than malate dehydrogenase (MDH), suggesting that DNAJC3 TPR domains might exhibit substrate specificity that has not been reported before. Preliminary ex vivo analysis of DNAJC3 in mammalian cells showed that induced stress conditions did not alter the cytosolic or endoplasmic reticulum (ER) localization, or levels of DNAJC3 protein, suggesting that the protein is not stress inducible. However, protein levels of DNAJC3 were dramatically reduced by Hsp90 inhibitor novobiocin at 500 μM. Transient knockdown DNAJC3 did not change the protein levels of either Grp78 or Grp94, but decreased the protein levels of Hsp70/Hsp90 organizing protein HOP. On the other hand, protein levels of DNAJC3 were increased in HOP depleted cells. In conclusion, this study was the first to experimentally demonstrate that DNAJC3 TPR domains do not interact directly with Hsp90, Hsp70, Grp78 or Grp94, and therefore DNAJC3 is unlikely to participate in traditional co-chaperone interactions with those proteins via its TPR domain. However, the J domain is known to interact with Grp78. The discovery that DNAJC3 TPR domains resemble that of TPR-containing proteins with functions independent of Hsp90 or Hsp70 suggests that DNAJC3 might link the Hsp70/Grp78 chaperone machinery to non co-chaperone related functions, which requires further analysis

Predictors of users' preferences for digital information at the oceanographic research institute (ORI), Durban.

Thesis (M.I.S.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.This research was a case study that investigated predictors of users’ preferences for digital information at the Oceanographic Research Institute (ORI) Library in Durban, South Africa. The objectives of the study were to determine the predictors of users’ preferences for digital information, examine user attitude towards use of digital information, evaluate user competencies in the use of digital information, examine available ICT infrastructure to facilitate access to digital information and assess usage patterns of electronic resources. Technology Acceptance Model (TAM) was used to underpin the study, using the mixed method paradigm consisting of qualitative and quantitative methods. A census of the study population, consisting of 26 respondents, was taken. Data was collected using focus group discussions, semi-structured interviews, participant observations, document reviews and survey questionnaires. Quantitative data was analysed using descriptive statistics, while qualitative data was analysed thematically. The findings of the study indicated that there was increasing preference of digital information to print by scholars. Moreover, usage of digital information was high by virtue of being easy to use and useful for scholarly work. The findings revealed that scholars had developed a positive attitude towards digital information. In addition, user experience with computers and the availability of infrastructure within the organisation were found to be facilitating conditions for digital information usage behaviour. The findings showed that respondents lacked relevant skills for the effective use of digital information and the ORI Library lacked adequate computers and electronic resources to satisfy user needs. The study recommended the development of a digital repository, user training to improve use of digital information resources. Suggested areas for research included examining the use of electronic resources in marine and aquatic institutions in Africa to establish grounds for collaborations and resource sharing. A study to assess the quality of research output by scholars was also recommended, as a way of exposing the critical or non-critical use of digital sources

Institutional repositories as platforms for open access in South African universities : the case of University of KwaZulu-Natal.

Doctor of Philosophy in Information Studies. University of KwaZulu-Natal, Pietermaritzburg, 2019.For a long time, academic libraries struggled to provide access to scholarly literature, including that which was produced by their own academic community due to paywalls. However, with the growth of internet technology that enables faster and free dissemination of information, universities are embracing institutional repositories (IR) because they are an economic means of sharing scholarship worldwide. This study examined the development, and extent of use of the repository by academics at the University of KwaZulu-Natal’s (UKZN), so that strategies to improve usage could be recommended. This investigation grew after the realisation that access to scholarly literature has particularly been a major obstacle in Africa and the developing countries mainly because of tight library budgets. As repositories promote open access (OA) to scholarly literature within the global research community, it is viewed as Africa’s solution to improved access to scholarly communication. Informed by the Unified Theory of Acceptance and Use of Technology (UTAUT) model, this study employed the mixed method paradigm, where quantitative data was collected from academics and qualitative data from interviews. Documents were reviewed to corroborate field data. The findings revealed that the repository has consistently been growing in terms of size and diversity. The signing of the Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities in 2012, the appointment of the IR Librarian in 2014 to manage IR duties, the draft OA policy, ongoing OA marketing and promotion activities and the availability of Information and Communication Technology (ICT) infrastructure were found as positive developments on the growth of the repository. Extent of use of the repository by academics was measured using UTAUT variables: performance expectancy, effort expectancy, social influence and facilitating conditions. Findings revealed that most academics believed that using the IR would benefit them but many of them had little to no knowledge about the university’s IR and their role in developing it. There was a general lack of skills amongst academics on self-archiving. A majority of academics believed that it would be easy for them to use the repository, especially if high profile researchers in the field, fellow academics, the university and research funders were positively influencing them to use the repository. Findings on ICT infrastructure necessary to support self-archiving, showed that UKZN had adequate infrastructure in place but academics believed that facilitating conditions in the form of rewards would encourage them to participate. Academics' attitudes on the IR was positive, but use was hindered by a lack of knowledge, fear of plagiarism, uncertainty of preservation and integrity of their work and the availability of other suitable platforms where they could share their work. Strategies recommended to improve IR use at UKZN included implementing an OA mandatory policy, strengthening OA education and IR training programmes to improve academics awareness, devising a reward system to recognise academics that were self-archiving, taking advantage of social factors to influence academics into using the IR and concerted efforts from the government, research funders and universities on OA. The study concludes that there is potential to improve IR use at UKZN and to enhance the access and visibility of its scholarship to the global research community

Ethical climate fit, leader-member exchange and employee job outcomes

The study sought to investigate whether the effects of an employee’s fit or misfit with the ethical climate of an organisation is mitigated or exacerbated by the quality of the leader-member exchange experienced. The outcome variables looked at includes organisational commitment, job satisfaction and turnover intentions. Data was gathered from a total sample of 125 employees from three different non profit making organisations. Pearson Product Moment Correlations and moderated regressions were used to address the main research questions of the study. Despite, the implied theoretical link between ethical climate fit and leader member exchange, partly as a function of the constructs being centred on the notion of fit, and the role organisational leaders play in the formation of ethical climates, no significant moderation effects were found. Both variables were found to relate significantly to all job outcomes, but no combined effects of these variables on job outcomes were found. The findings of the study highlight a need for further empirical research on these concepts, and for the inquiring of existing theoretical propositions linking leaders to ethical climates

Monetary policy transmission and house prices, a VAR approach: a case study of South Africa (1994 to 2011)

Thesis (M.M. (Finance & Investment))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Business Administration, 2013.We analyse the role of financial and macro-economic variables in the conduct of monetary policy, particularly the role played by monetary policy in the house price boom of the early 2000s. The analysis is performed in the setup of a New Keynesian open economy. We estimate a five variable Recursive Vector Autoregressive model consisting of the short term interest rate, house prices, inflation, output and the exchange rate. Quarterly data from 1994 to 2011 was inputted in Eviews (6) to run the model. We find a significant causal relationship between the short term interest rate and house prices; the impulse response results show an instant response of house prices to a shock in monetary policy. We conclude that the house price boom of the early 2000s was partially attributed to an overreaction to a shock in monetary policy. We also find evidence of exchange rate pass- through to the consumer price index as in (Mishkin, 2008).We conclude that perhaps monetary policy should take cognisance of asset price fluctuations and exchange rate volatility in determining the policy instrumen

Kaposi Sarcoma-Associated Herpesvirus Glycoprotein H Is Indispensable for Infection of Epithelial, Endothelial, and Fibroblast Cell Types

Kaposi sarcoma-associated herpesvirus (KSHV) is an emerging pathogen and is the causative infectious agent of Kaposi sarcoma and two malignancies of B cell origin. To date, there is no licensed KSHV vaccine. Development of an effective vaccine against KSHV continues to be limited by a poor understanding of how the virus initiates acute primary infection in vivo in diverse human cell types. The role of glycoprotein H (gH) in herpesvirus entry mechanisms remains largely unresolved. To characterize the requirement for KSHV gH in the viral life cycle and in determination of cell tropism, we generated and characterized a mutant KSHV in which expression of gH was abrogated. Using a bacterial artificial chromosome containing a complete recombinant KSHV genome and recombinant DNA technology, we inserted stop codons into the gH coding region. We used electron microscopy to reveal that the gH-null mutant virus assembled and exited from cells normally, compared to wild-type virus. Using purified virions, we assessed infectivity of the gH-null mutant in diverse mammalian cell types in vitro. Unlike wild-type virus or a gH-containing revertant, the gH-null mutant was unable to infect any of the epithelial, endothelial, or fibroblast cell types tested. However, its ability to infect B cells was equivocal and remains to be investigated in vivo due to generally poor infectivity in vitro. Together, these results suggest that gH is critical for KSHV infection of highly permissive cell types, including epithelial, endothelial, and fibroblast cells. IMPORTANCE All homologues of herpesvirus gH studied to date have been implicated in playing an essential role in viral infection of diverse permissive cell types. However, the role of gH in the mechanism of KSHV infection remains largely unresolved. In this study, we generated a gH-null mutant KSHV and provided evidence that deficiency of gH expression did not affect viral particle assembly or egress. Using the gH-null mutant, we showed that gH was indispensable for KSHV infection of epithelial, endothelial, and fibroblast cells in vitro. This suggests that gH is an important target for the development of a KSHV prophylactic vaccine to prevent initial viral infection

Kaposi Sarcoma-associated Herpesvirus Glycoprotein H is Indispensable for Infection of Epithelial, Endothelial, and Fibroblast Cell Types

Kaposi sarcoma-associated herpesvirus (KSHV) is an emerging pathogen and is the causative infectious agent of Kaposi sarcoma and two malignancies of B cell origin. To date, there is no licensed KSHV vaccine. Development of an effective vaccine against KSHV continues to be limited by a poor understanding of how the virus initiates acute primary infection in vivo in diverse human cell types. The role of glycoprotein H (gH) in herpesvirus entry mechanisms remains largely unresolved. To characterize the requirement for KSHV gH in the viral life cycle and in determination of cell tropism, we generated and characterized a mutant KSHV in which expression of gH was abrogated. Using a bacterial artificial chromosome containing a complete recombinant KSHV genome and recombinant DNA technology, we inserted stop codons into the gH coding region. We used electron microscopy to reveal that the gH-null mutant virus assembled and exited from cells normally, compared to wild-type virus. Using purified virions, we assessed infectivity of the gH-null mutant in diverse mammalian cell types in vitro Unlike wild-type virus or a gH-containing revertant, the gH-null mutant was unable to infect any of the epithelial, endothelial, or fibroblast cell types tested. However, its ability to infect B cells was equivocal, and remains to be investigated in vivo due to generally poor infectivity in vitro Together, these results suggest that gH is critical for KSHV infection of highly permissive cell types including epithelial, endothelial, and fibroblasts. MPORTANCE: All homologues of herpesvirus gH studied to date have been implicated in playing an essential role in viral infection of diverse permissive cell types. However, the role of gH in the mechanism of KSHV infection remains largely unresolved. In this study, we generated a gH-null mutant KSHV and provided evidence that deficiency of gH expression did not affect viral particle assembly or egress. Using the gH-null mutant, we showed that gH was indispensable for KSHV infection of epithelial, endothelial, and fibroblast cells in vitro. This suggests that gH is an important target for the development of a KSHV prophylactic vaccine to prevent initial viral infection

Work-Related Stress in the Banking Sector: A Review of Incidence, Correlated Factors, and Major Consequences

For a number of years now, banks have been going through enormous changes in organization and structure. New technology and new ways of structuring the operation have left their mark on the working conditions and daily lives of employees. Deregulation of labor markets, emerging technologies and new types of jobs have significantly reshaping working lives by continuous changes on employment and working conditions. Such a scenario has a relevant impact not only on companies' organization but also on working population's health. The banking sector is particularly well-deserved of a specific and thorough analysis, in view of the recent increase in psycho-social disorders of employees. This may be related to the major organizational changes affecting this sector and, in particular, to the restructuring processes resulting from the global economic crisis. Our aim is to assess the scale of the phenomenon and how far it relates specifically to the processes of bank organization. With this in mind, through a review of the literature, we selected the main studies dealing with work-related stress in banking, so that we could reach a better understanding of the phenomenon as it relates specifically to this set of workers. The search took place on the MEDLINE® database; in total 20 articles were chosen. There was uniform agreement among the studies that stress in the banking workplace is now at critical levels, and that it can have deleterious psychological effects on workers, and on their physical health, and that organizations, too, are affected. Most studies showed that mental health problems had increased in the banking sector, and that they were stress-related. Examples began with anxiety and depression, carried on through maladaptive behaviors, and ended in job burnout. The reviewed studies' limitations were then discussed, and possible ways forward considered

Investigating the role of heat shock proteins 40, 70 and 90 in the life cycle of a picornavirus, Theiler's murine encephalomyelitis virus

Introduction: Picornaviruses are a family of RNA viruses which are economically and clinically significant. Like many other viruses, picornaviruses utilise host cell machinery to facilitate their replication and assembly, including heat shock proteins (Hsps). The aim of this research was to investigate the role of Hsp40, Hsp70 and Hsp90 during picornavirus infection using the cardiovirus, Theiler’s murine encephalomyelitis virus (TMEV), as a study model. Methodology: Picornavirus VP1 capsid proteins were analysed by multiple sequence alignment and multiple structural comparisons. Protein domain architecture was used to analyse Hsp90 cellular and viral client proteins. Effects of Hsp90 inhibitors, novobiocin and geldanamycin, on TMEV growth in BHK-21 cells was observed over a 48hr period. Localisation of Hsp40, Hsp90 and Hsp70 in TMEV-infected BHK-21 cells was investigated by indirect immunofluorescence and confocal microscopy. Results and Discussion: VP1 proteins of picornaviruses are highly divergent within the family at the amino acid level, which might be linked to the protein’s function in determining virus tropism and antibody neutralisation. An eight-stranded anti-parallel beta-barrel structure was found conserved in the VP1 protein structures which might be linked to the highly conserved picornavirus capsid assembly process. Absence of a common protein domain between Hsp90 viral and cellular client proteins that might be functionally connected to Hsp90, suggests that Hsp90 most likely recognises surface features rather than sequence motifs/patterns. The Hsp90 inhibitors, novobiocin and geldanamycin, had a negative effect on virus growth as virus-induced cytopathic effect was not observed in treated cell after 48hrs. TMEV 2C protein was detected by Western analysis in infected cell lysates treated with geldanamycin but not novobiocin, suggesting novobiocin affects the translation or processing of TMEV 2C. Immunofluorescence analysis of TMEV-infected cells showed a relocalisation of Hsp40 into the nucleus during infection. Overlap of Hsp40 and TMEV P1 was observed in the perinuclear region, suggesting colocalisation between these proteins. Hsp70 converged around the replication complex during infection but did not overlap with TMEV 2C. Hsp90 concentrated in the region of the replication complex where it overlapped with TMEV 2C and this redistribution was found to be dependent on the stage of infection. The overlap between Hsp90 and TMEV 2C signals observed, suggested colocalisation between the two proteins. Conclusion: This study identified Hsp90, Hsp70 and Hsp40 as possible host factors required in TMEV replication