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Melissa Reynell van der Ross, Chantal Olckers, Pieter Schaap Department of Human Resource Management, Faculty of Economic and Management Sciences, University of Pretoria, Pretoria, South AfricaCorrespondence: Melissa Reynell van der Ross, Email reynellvanderross@gmail.comPurpose: Globally, the pandemic had adverse consequences on the engagement and overall well-being of individuals. From a positive psychological perspective, this study drew on processes of social exchange, Kahn’s theory on personal engagement and crossover theory, to explore the impact of mutual influences among academic staff and students on the engagement of both parties. Subsequently, the study explored the positive outcomes of engagement for both academic staff and students.Participants and Methods: Purposive, non-probability sampling was used, and cross-sectional data were collected through electronic surveys. The sample consisted of a total of 1594 students who were nested within 160 academic staff members.Results: Findings highlighted the influence of interpersonal factors such as high student leader–member exchange on student engagement and the impact of students’ lack of reciprocity on the emotional engagement of academic staff. Findings further revealed that student engagement was positively related to a deep-learning approach and negatively related to a surface-learning approach. Furthermore, this study found a positive significant association between the emotional engagement and the psychological well-being of academic staff.Conclusion: Against the backdrop of the COVID-19 pandemic and to reduce the negative psychological and behavioural challenges resulting from the pandemic, this research intended to inform policy-makers in higher education of the impact that mutual influences among academic staff and students have on their engagement and the benefits of engagement in cultivating a culture of life-long learning among students and improving the psychological well-being of academic

Due to the importance of artificial intelligence (AI) in a variety of high-stakes decisions, such as loan approval, job hiring, and criminal bail, researchers in Explainable AI (XAI) have developed algorithms to provide users with recourse for an unfavorable outcome. We analyze the incentives for a decision-maker to offer recourse to a set of applicants. Does the decision-maker have the incentive to offer recourse to all rejected applicants? We show that the decision-maker only offers recourse to all applicants in extreme cases, such as when the recourse process is impossible to manipulate. Some applicants may be worse off when the decision-maker can offer recourse.

In peer mechanisms, the competitors for a prize also determine who wins. Each competitor may be asked to rank, grade, or nominate peers for the prize. Since the prize can be valuable, such as financial aid, course grades, or an award at a conference, competitors may be tempted to manipulate the mechanism. We survey approaches to prevent or discourage the manipulation of peer mechanisms. We conclude our survey by identifying several important research challenges.

Realisation of the value and the commercialisation potential of data is gaining exponential momentum. The combination of historical data exploitations and the use of technologies that allow for the triangulation of data results in the collection, storage, and processing of massive amounts of data require diligent data management, including adherence to privacy and other laws, both nationally and internationally. The intrinsic value of scientific data, especially in genomics, becomes apparent when data are shared, often in collaboration with international partners, and compiled into big data sets that are subsequently used for benefit, including commercial benefit. The purpose of this article is to explore the commercialisation of data in South Africa against the backdrop of the legal framework governing the protection of personal information, confidentiality and privacy, with a specific focus on genetic and genomic information. Related issues, such as the collection and sharing of data, ownership of data and challenges about informed consent are also considered. After a brief evaluation of the African regulatory landscape relating to the protection of personal information, the article concludes with a few recommendations aimed at improving the status quo and sensitising the South African public as to the value of their data and personal information, as well as the potential uses and abuses to which their personal information may be subjected.

The information and communication technology (ICT) sector within the Netherlands is a major driver of globalization, the country’s economic growth and innovation. The Dutch ICT sector’s performance is increasingly becoming dependent upon employee driven innovations in order to address the needs of the sectors they service. In other words, the ICT sector within the Netherlands is largely dependent upon the performance and innovative capacity of its employees; both of which are functions of employee engagement. Given the high demand, and low supply of talent within this sector, ICT organizations need to develop innovative ways to enhance the performance capacities of its people. Developing an engaged and highly innovative workforce seems to be an efficient way to activate employees’ performance. As such, the aim of this paper was to investigate the mediating function of employee driven innovative work behaviors in the relationship between work engagement and task performance within the a Dutch ICT consulting firm. A cross-sectional survey-based research design, employing a census-based sampling method, was employed to obtain data from a global ICT consulting firm within the Netherlands (n = 232). The Utrecht Work Engagement Scale, the Innovative Work Behavior Scale and the Task Performance Scale was used to assess the associative subjective experiences of ICT employees. The results showed that work engagement is a significant driver for innovative work behaviors, which in turn affects the task performance of employees. Further, innovative work behaviors are therefore important to translate the engaging energies of employees into performance. This paper discusses the theoretical and practical implications of these findings.

Realisation of the value and the commercialisation potential of data is gaining exponential momentum. The combination of historical data exploitations and the use of technologies that allow for the triangulation of data results in the collection, storage, and processing of massive amounts of data require diligent data management, including adherence to privacy and other laws, both nationally and internationally. The intrinsic value of scientific data, especially in genomics, becomes apparent when data are shared, often in collaboration with international partners, and compiled into big data sets that are subsequently used for benefit, including commercial benefit. The purpose of this article is to explore the commercialisation of data in South Africa against the backdrop of the legal framework governing the protection of personal information, confidentiality and privacy, with a specific focus on genetic and genomic information. Related issues, such as the collection and sharing of data, ownership of data and challenges about informed consent are also considered. After a brief evaluation of the African regulatory landscape relating to the protection of personal information, the article concludes with a few recommendations aimed at improving the status quo and sensitising the South African public as to the value of their data and personal information, as well as the potential uses and abuses to which their personal information may be subjected.

The information and communication technology (ICT) sector within the Netherlands is a major driver of globalization, the country’s economic growth and innovation. The Dutch ICT sector’s performance is increasingly becoming dependent upon employee driven innovations in order to address the needs of the sectors they service. In other words, the ICT sector within the Netherlands is largely dependent upon the performance and innovative capacity of its employees; both of which are functions of employee engagement. Given the high demand, and low supply of talent within this sector, ICT organizations need to develop innovative ways to enhance the performance capacities of its people. Developing an engaged and highly innovative workforce seems to be an efficient way to activate employees’ performance. As such, the aim of this paper was to investigate the mediating function of employee driven innovative work behaviors in the relationship between work engagement and task performance within the a Dutch ICT consulting firm. A cross-sectional survey-based research design, employing a census-based sampling method, was employed to obtain data from a global ICT consulting firm within the Netherlands (n = 232). The Utrecht Work Engagement Scale, the Innovative Work Behavior Scale and the Task Performance Scale was used to assess the associative subjective experiences of ICT employees. The results showed that work engagement is a significant driver for innovative work behaviors, which in turn affects the task performance of employees. Further, innovative work behaviors are therefore important to translate the engaging energies of employees into performance. This paper discusses the theoretical and practical implications of these findings.

Mobile phone-based gambling has grown wildly popular in Africa. Com-mentators worry that low ability gamblers will not learn from experience, and may rely on debt to gamble. Using data on financial transactions for over 50 000 Kenyan smartphone users, we find that gamblers do learn from experience. Gamblers are less likely to bet following poor results and more likely to bet fol-lowing good results. The reaction to positive and negative feedback is of equal magnitude, and is consistent with a model of Bayesian updating. Using an instrumental variables strategy, we find no evidence that increased gambling leads to increased debt.

Mobile phone-based gambling has grown wildly popular in Africa. Com-mentators worry that low ability gamblers will not learn from experience, and may rely on debt to gamble. Using data on financial transactions for over 50 000 Kenyan smartphone users, we find that gamblers do learn from experience. Gamblers are less likely to bet following poor results and more likely to bet fol-lowing good results. The reaction to positive and negative feedback is of equal magnitude, and is consistent with a model of Bayesian updating. Using an instrumental variables strategy, we find no evidence that increased gambling leads to increased debt.

A Corrigendum on "The Psychometric Properties of the Grit-O Scale Within the Twente Region in Netherlands: An ICM-CFA vs. ESEM Approach" by van Zyl, L. E., Olckers, C., and Roll, L. C. (2020). Frontiers in psychology 11.2020, 796. doi: 10.3389/fpsyg.2020.00796

The purpose of this study was to examine the psychometric properties (i.e., factorial validity, measurement invariance, and reliability) of the Grit-Original scale (Grit-O) within the Netherlands. The Grit-O scale was subjected to a competing measurement modeling strategy that sequentially compared both independent cluster model confirmatory factor analytical- and exploratory structural equation modeling approaches. The results showed that both a two first order, bi-factor structure as well as a less restrictive two factor ESEM factorial structure best-fitted the data. The instrument showed to be reliable at both a lower- (Cronbach’s alpha) and upper-level (composite reliability) limit. However, measurement invariance between genders could only be established for the B-ICM-CFA model. Finally, concurrent validity was established through relating the GRIT-O to task performance. The linear use of the Grit-O scale should therefore carefully be considered.

BACKGROUND: There are several reports on underdiagnosis of COPD, while little is known about COPD overdiagnosis and overtreatment. We describe the overdiagnosis and the prevalence of spirometrically defined false positive COPD, as well as their relationship with overtreatment across 23 population samples in 20 countries participating in the BOLD Study between 2003 and 2012. METHODS: A false positive diagnosis of COPD was considered when participants reported a doctor's diagnosis of COPD, but postbronchodilator spirometry was unobstructed (FEV1/FVC > LLN). Additional analyses were performed using the fixed ratio criterion (FEV1/FVC < 0.7). RESULTS: Among 16,177 participants, 919 (5.7%) reported a previous medical diagnosis of COPD. Postbronchodilator spirometry was unobstructed in 569 subjects (61.9%): false positive COPD. A similar rate of overdiagnosis was seen when using the fixed ratio criterion (55.3%). In a subgroup analysis excluding participants who reported a diagnosis of "chronic bronchitis" or "emphysema" (n = 220), 37.7% had no airflow limitation. The site-specific prevalence of false positive COPD varied greatly, from 1.9% in low- to middle-income countries to 4.9% in high-income countries. In multivariate analysis, overdiagnosis was more common among women, and was associated with higher education; former and current smoking; the presence of wheeze, cough, and phlegm; and concomitant medical diagnosis of asthma or heart disease. Among the subjects with false positive COPD, 45.7% reported current use of respiratory medication. Excluding patients with reported asthma, 34.4% of those with normal spirometry still used a respiratory medication. CONCLUSIONS: False positive COPD is frequent. This might expose nonobstructed subjects to possible adverse effects of respiratory medication., Group Author(s): BOLD Collaborative Res Grp

The information and communication technology (ICT) sector within the Netherlands is a major driver of globalization, the country’s economic growth and innovation. The Dutch ICT sector’s performance is increasingly becoming dependent upon employee driven innovations in order to address the needs of the sectors they service. In other words, the ICT sector within the Netherlands is largely dependent upon the performance and innovative capacity of its employees; both of which are functions of employee engagement. Given the high demand, and low supply of talent within this sector, ICT organizations need to develop innovative ways to enhance the performance capacities of its people. Developing an engaged and highly innovative workforce seems to be an efficient way to activate employees’ performance. As such, the aim of this paper was to investigate the mediating function of employee driven innovative work behaviors in the relationship between work engagement and task performance within the a Dutch ICT consulting firm. A cross-sectional survey-based research design, employing a census-based sampling method, was employed to obtain data from a global ICT consulting firm within the Netherlands (n = 232). The Utrecht Work Engagement Scale, the Innovative Work Behavior Scale and the Task Performance Scale was used to assess the associative subjective experiences of ICT employees. The results showed that work engagement is a significant driver for innovative work behaviors, which in turn affects the task performance of employees. Further, innovative work behaviors are therefore important to translate the engaging energies of employees into performance. This paper discusses the theoretical and practical implications of these findings.

The study aimed to examine the psychometric properties of the MHC-SF within selected organisational contexts. Specifically, the aim was to determine the factorial validity, measurement invariance, and reliability of the instrument for South African organisations. A cross-sectional online survey-based research design was employed, coupled with a convenience sampling strategy (N = 624). The results showed that the original three-dimensional factor structure of the MHC-SF fitted the data the best. Items loaded statistically significantly on all three subscales (emotional, psychological, social wellbeing). Further, the scale showed full configure, convergent and metric invariance between males and females. However, invariance was not established in either age cohorts, language groups, or marital status. The instrument proved to be reliable at both a lower (Cronbach Alpha) and upper level (Composite reliability) limit within South African organisational contexts.

We analyze the design of a mechanism to extract a ranking of individuals according to a unidimensional characteristic, such as ability or need. Individuals, connected on a social network, only have local information about the ranking. We show that a planner can construct an ex post incentive compatible and efficient mechanism if and only if every pair of friends has a friend in common. We characterize the windmill network as the sparsest social network for which the planner can always construct a complete ranking., Comment: final version for publication at AEJ: Micro

Contains fulltext : 189933.pdf (publisher's version ) (Open Access)

Contains fulltext : 189933.pdf (publisher's version ) (Open Access)

Psychological ownership is a cognitive–affective construct based on individuals’ feelings of possessiveness towards and of being psychologically tied/attached to objects that are material (e.g. tools or work) and immaterial (e.g. ideas or workspace) in nature. Research suggests that psychological ownership could be influenced by various individual, organisational and contextual factors. The South African Employment Equity Act, which was implemented to grant equitable opportunities to previously disadvantaged employees, could be a significant contextual factor affecting psychological ownership, due to perceptions associated with inequality. Ethnicity may also act as a moderator for the relationship between perceptions of employment equity and psychological ownership. The objective of this study was to investigate the relationship between employment equity perceptions and psychological ownership and to explore whether ethnicity plays a moderating role in the relationship. A cross-sectional survey design was employed with a purposeful sample of 202 respondents employed in a large South African mining house. Pearson product–moment correlations and structural equation modelling confirmed that employment equity perceptions could predict the five components of psychological ownership. However, the results revealed that ethnicity has no moderating effect on the relationship between perceptions of employment equity and the emergence of psychological ownership. By implication, organisations that seek to retain employees targeted through equity initiatives need to find ways to enhance and develop the psychological ownership of these employees. The research contributes new insights into and knowledge of how contextual factors could influence employees’ psychological ownership.

Motivation This project was of specific importance to the private security industry, victims of residential burglary, community policing forums and the South African Police Service in providing detailed information regarding recommendations of how to manage and combat residential burglary in two selected northern suburbs of Johannesburg. Problem statement Residential burglary is categorised in the top three highest reported crimes according to the official South African Police Service statistics for the 2006/7 financial years. A series of victim interviews, docket analysis, case plotting and residential security audit surveys were conducted to determine the extent (or lack thereof) of security measures at a burgled residence in the selected area. Approach Field data was collected through docket analysis, plotting crime scenes (descriptive mapping), victim interviews and residential security audit surveys. Results The majority of victims of burglary interviewed did not have the minimum security system (integrated measures) in place. Those victims, who had security measures, appeared not to have made or implemented effective use of them. Conclusion Security at a residence extends beyond just the immediate house area and the focus (security risk assessment) should start with the immediate neighbourhood (community) area working inwards towards the property perimeter (boundary), inner perimeter (garden area) and then finally the immediate house area.

Type II diabetes mellitus is currently globally one of the fastest growing non- communicable diseases, especially in developing countries. This investigation reports on a meta-analysis undertaken of the C-11377G locus within the adiponectin gene in a black South African, a Cuban Hispanic and a German Caucasian cohort. Genotyping was performed via a real-time PCR strategy. Both fixed- and random-effects models were tested to describe the diabetes risk at both the cohort and population levels. The 2, 2 genotype may only be associated with increased diabetes risk in the Cuban Hispanic cohort. Population-specific effects may have masked these associations upon meta-analytical analysis, as no significant odds ratio could be determined. Thus, to examine diabetes risk, a more global approach including the design of population-specific experimental strategies should be used, which will be crucial in developing health education and policies in a global health programme.

This study was aimed to compare prevalences of the metabolic syndrome in Africans using five definitions as proposed by the World Health Organization (WHO), the European Group for the Study of Insulin Resistance (EGIR), the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults [Adult Treatment Panel (ATPIII)], the American College of Endocrinology (ACE), and the International Diabetes Federation (IDF). A further objective was to identify difficulties in classifying Africans with the metabolic syndrome and to suggest specific areas where criteria adjustments for identifying Africans should be made. A case-case-control cross-sectional study involved 102 urban African women. Except for microalbumin data, all data necessary for classification of the metabolic syndrome were collected, including fasting and 2-h glucose and insulin, anthropometric measurements, blood pressure, and lipids. The metabolic syndrome prevalences ranged from 5.4% (EGIR), 15.7% (ATPIII), >or=19.4% (WHO), 24.8% (IDF) to 25.5% (ACE). Only 2.9% (n=3) had a triglyceride level >or=1.69 mmol/l, but 58.8% (n=60) had a HDL-level <1.29 mmol/l, whereas 27% (n=26) were insulin resistant, 22.3% (n=21), had a blood pressure >or=140/90 or used hypertension medication. It seems as if the classification of hypertension, insulin resistance and hyperglycemia might have been adequate, but body composition and dyslipidemia criteria need adjustment for Africans. Since neither definition seems completely suitable for Africans it is suggested that clinical emphasis should rather be on treating any specific cardiovascular disease risk factor that is present, than on diagnosing a patient with the metabolic syndrome.

This study was aimed to compare prevalences of the metabolic syndrome in Africans using five definitions as proposed by the World Health Organization (WHO), the European Group for the Study of Insulin Resistance (EGIR), the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults [Adult Treatment Panel (ATPIII)], the American College of Endocrinology (ACE), and the International Diabetes Federation (IDF). A further objective was to identify difficulties in classifying Africans with the metabolic syndrome and to suggest specific areas where criteria adjustments for identifying Africans should be made. A case-case-control cross-sectional study involved 102 urban African women. Except for microalbumin data, all data necessary for classification of the metabolic syndrome were collected, including fasting and 2-h glucose and insulin, anthropometric measurements, blood pressure, and lipids. The metabolic syndrome prevalences ranged from 5.4% (EGIR), 15.7% (ATPIII), >or=19.4% (WHO), 24.8% (IDF) to 25.5% (ACE). Only 2.9% (n=3) had a triglyceride level >or=1.69 mmol/l, but 58.8% (n=60) had a HDL-level <1.29 mmol/l, whereas 27% (n=26) were insulin resistant, 22.3% (n=21), had a blood pressure >or=140/90 or used hypertension medication. It seems as if the classification of hypertension, insulin resistance and hyperglycemia might have been adequate, but body composition and dyslipidemia criteria need adjustment for Africans. Since neither definition seems completely suitable for Africans it is suggested that clinical emphasis should rather be on treating any specific cardiovascular disease risk factor that is present, than on diagnosing a patient with the metabolic syndrome.

Type II diabetes mellitus is currently globally one of the fastest growing non- communicable diseases, especially in developing countries. This investigation reports on a meta-analysis undertaken of the C-11377G locus within the adiponectin gene in a black South African, a Cuban Hispanic and a German Caucasian cohort. Genotyping was performed via a real-time PCR strategy. Both fixed- and random-effects models were tested to describe the diabetes risk at both the cohort and population levels. The 2, 2 genotype may only be associated with increased diabetes risk in the Cuban Hispanic cohort. Population-specific effects may have masked these associations upon meta-analytical analysis, as no significant odds ratio could be determined. Thus, to examine diabetes risk, a more global approach including the design of population-specific experimental strategies should be used, which will be crucial in developing health education and policies in a global health programme.

Background: Genetic variation in the β2 (ADRB2) and β3 (ADRB3) adrenergic receptor genes are associated with obesity and insulin resistance. To further elucidate the role of these genes in the pathophysiology of obesity the present study investigated associations between certain polymorphisms in ADRB2 and ADRB3 and parameters of carbohydrate and lipid metabolism in a population of African origin. Material and Methods: Data of 102 black South African women obtained in the POWIRS (Profile of Obese Women with the Insulin Resistance Syndrome) study were used. Endpoint measurements included several anthropometric variables, resting blood pressure, plasma glucose, insulin, free fatty acids (FFA), ghrelin, leptin and lipids, and insulin resistance as estimated by the homeostasis model assessment (HOMA-IR) index. Polymorphisms were analyzed via PCR based methods. Results: The percentage body fat was significantly lower (p≤0.05) and the FFA significantly higher (p≤0.05) in lean subjects (BMI≤25 kg/m2) with the Glu27 variant allele compared to subjects with the Gln27 wildtype allele of the ADRB2 gene. In contrast, the variant allele of the ADRB2 gene was significantly positive associated (p≤0.05) with the HOMA-IR-index in overweight black African women (BMI>25 kg/m2). No significant differences in parameters of the metabolic syndrome were apparent between subjects with the wildtype and variant alleles in the ADRB3 gene. Conclusion: The presence of the Glu27 and Arg64 polymorphisms of the ADRB2 and ADRB3 genes are not directly related to indices of the metabolic syndrome

Background: Genetic variation in the β2 (ADRB2) and β3 (ADRB3) adrenergic receptor genes are associated with obesity and insulin resistance. To further elucidate the role of these genes in the pathophysiology of obesity the present study investigated associations between certain polymorphisms in ADRB2 and ADRB3 and parameters of carbohydrate and lipid metabolism in a population of African origin. Material and Methods: Data of 102 black South African women obtained in the POWIRS (Profile of Obese Women with the Insulin Resistance Syndrome) study were used. Endpoint measurements included several anthropometric variables, resting blood pressure, plasma glucose, insulin, free fatty acids (FFA), ghrelin, leptin and lipids, and insulin resistance as estimated by the homeostasis model assessment (HOMA-IR) index. Polymorphisms were analyzed via PCR based methods. Results: The percentage body fat was significantly lower (p≤0.05) and the FFA significantly higher (p≤0.05) in lean subjects (BMI≤25 kg/m2) with the Glu27 variant allele compared to subjects with the Gln27 wildtype allele of the ADRB2 gene. In contrast, the variant allele of the ADRB2 gene was significantly positive associated (p≤0.05) with the HOMA-IR-index in overweight black African women (BMI>25 kg/m2). No significant differences in parameters of the metabolic syndrome were apparent between subjects with the wildtype and variant alleles in the ADRB3 gene. Conclusion: The presence of the Glu27 and Arg64 polymorphisms of the ADRB2 and ADRB3 genes are not directly related to indices of the metabolic syndrome

Contains fulltext : 50564.pdf (publisher's version ) (Closed access), The role of MT (metallothionein) gene expression was investigated in rotenone-treated HeLa cells to induce a deficiency of NADH:ubiquinone oxidoreductase (complex I). Complex I deficiency leads to a diversity of cellular consequences, including production of ROS (reactive oxygen species) and apoptosis. HeLa cells were titrated with rotenone, resulting in dose-dependent decrease in complex I activity and elevated ROS production at activities lower than 33%. Expression of MT2A (MT isoform 2A), but not MT1A or MT1B RNA, was significantly inducible by rotenone (up to 7-fold), t-BHP (t-butyl hydroperoxide; 5-fold) and CdCl2 (50-fold), but not ZnCl2. Myxothiazol treatment did not elevate either ROS or MT2A levels, which supports a ROS-related mechanism for rotenone-induced MT2A expression. To evaluate the role of MT2A expression, MT2A and MT1B were overexpressed in HeLa cells and treated with rotenone. Compared with control and MT1B-overexpressing cells, ROS production was significantly lower and cell viability higher in MT2A-overexpressing HeLa cells when ROS production was enhanced by treatment with t-BHP. Mitochondrial membrane potential was noticeably less reduced in both MT-overexpressing cell lines. MT2A overexpression in rotenone-treated cells also significantly reduced or delayed apoptosis induction, as measured by caspase 3/7 activity and cytosolic nucleosome enrichment. We conclude that MT2A offers significant protection against the main death-causing consequences of rotenone-induced complex I deficiency in HeLa cells. Our results are in support of the protective role against oxidative stress ascribed to MTs and provide evidence that MT2A expression may be a beneficial downstream adaptive response in complex I-deficient cells.

Contains fulltext : 50564.pdf (publisher's version ) (Closed access), The role of MT (metallothionein) gene expression was investigated in rotenone-treated HeLa cells to induce a deficiency of NADH:ubiquinone oxidoreductase (complex I). Complex I deficiency leads to a diversity of cellular consequences, including production of ROS (reactive oxygen species) and apoptosis. HeLa cells were titrated with rotenone, resulting in dose-dependent decrease in complex I activity and elevated ROS production at activities lower than 33%. Expression of MT2A (MT isoform 2A), but not MT1A or MT1B RNA, was significantly inducible by rotenone (up to 7-fold), t-BHP (t-butyl hydroperoxide; 5-fold) and CdCl2 (50-fold), but not ZnCl2. Myxothiazol treatment did not elevate either ROS or MT2A levels, which supports a ROS-related mechanism for rotenone-induced MT2A expression. To evaluate the role of MT2A expression, MT2A and MT1B were overexpressed in HeLa cells and treated with rotenone. Compared with control and MT1B-overexpressing cells, ROS production was significantly lower and cell viability higher in MT2A-overexpressing HeLa cells when ROS production was enhanced by treatment with t-BHP. Mitochondrial membrane potential was noticeably less reduced in both MT-overexpressing cell lines. MT2A overexpression in rotenone-treated cells also significantly reduced or delayed apoptosis induction, as measured by caspase 3/7 activity and cytosolic nucleosome enrichment. We conclude that MT2A offers significant protection against the main death-causing consequences of rotenone-induced complex I deficiency in HeLa cells. Our results are in support of the protective role against oxidative stress ascribed to MTs and provide evidence that MT2A expression may be a beneficial downstream adaptive response in complex I-deficient cells.

dal Daniele Olckers