scholarly journals Phenotypic Variation in Mitochondria-Related Performance Traits Across New Zealand Snail Populations

2020 ◽  
Vol 60 (2) ◽  
pp. 275-287
Author(s):  
Emma S Greimann ◽  
Samuel F Ward ◽  
James D Woodell ◽  
Samantha Hennessey ◽  
Michael R Kline ◽  
...  

Synopsis Mitochondrial function is critical for energy homeostasis and should shape how genetic variation in metabolism is transmitted through levels of biological organization to generate stability in organismal performance. Mitochondrial function is encoded by genes in two distinct and separately inherited genomes—the mitochondrial genome and the nuclear genome—and selection is expected to maintain functional mito-nuclear interactions. The documented high levels of polymorphism in genes involved in these mito-nuclear interactions and wide variation for mitochondrial function demands an explanation for how and why variability in such a fundamental trait is maintained. Potamopyrgus antipodarum is a New Zealand freshwater snail with coexisting sexual and asexual individuals and, accordingly, contrasting systems of separate vs. co-inheritance of nuclear and mitochondrial genomes. As such, this snail provides a powerful means to dissect the evolutionary and functional consequences of mito-nuclear variation. The lakes inhabited by P. antipodarum span wide environmental gradients, with substantial across-lake genetic structure and mito-nuclear discordance. This situation allows us to use comparisons across reproductive modes and lakes to partition variation in cellular respiration across genetic and environmental axes. Here, we integrated cellular, physiological, and behavioral approaches to quantify variation in mitochondrial function across a diverse set of wild P. antipodarum lineages. We found extensive across-lake variation in organismal oxygen consumption and behavioral response to heat stress and differences across sexes in mitochondrial membrane potential but few global effects of reproductive mode. Taken together, our data set the stage for applying this important model system for sexual reproduction and polyploidy to dissecting the complex relationships between mito-nuclear variation, performance, plasticity, and fitness in natural populations.

2017 ◽  
Author(s):  
Emma S. Greimann ◽  
Samuel F. Ward ◽  
James D. Woodell ◽  
Samantha Hennessey ◽  
Michael R. Kline ◽  
...  

ABSTRACTMitochondrial function is critical for energy homeostasis and should shape how genetic variation in metabolism is transmitted through levels of biological organization to generate stability in organismal performance. Mitochondrial function is encoded by genes in two distinct and separately inherited genomes – the mitochondrial genome and the nuclear genome – and selection is expected to maintain functional mito-nuclear interactions. Nevertheless, high levels of polymorphism in genes involved in these mito-nuclear interactions and variation for mitochondrial function are nevertheless frequently observed, demanding an explanation for how and why variability in such a fundamental trait is maintained. Potamopyrgus antipodarum is a New Zealand freshwater snail with coexisting sexual and asexual individuals and, accordingly, contrasting systems of separate vs. co-inheritance of nuclear and mitochondrial genomes. As such, this snail provides a powerful means to dissect the evolutionary and functional consequences of mito-nuclear variation. The lakes inhabited by P. antipodarum span wide environmental gradients, with substantial across-lake genetic structure and mito-nuclear discordance. This situation allows us to use comparisons across reproductive modes and lakes to partition variation in cellular respiration across genetic and environmental axes. Here, we integrated cellular, physiological, and behavioral approaches to quantify variation in mitochondrial function across a diverse set of wild P. antipodarum lineages. We found extensive across-lake variation in organismal oxygen consumption, mitochondrial membrane potential, and behavioral response to heat stress, but few global effects of reproductive mode or sex. Taken together, our data set the stage for applying this important model system for sexual reproduction and polyploidy to dissecting the complex relationships between mito-nuclear variation, performance, plasticity, and fitness in natural populations.


2016 ◽  
Author(s):  
Joel Sharbrough ◽  
Jennifer L. Cruise ◽  
Megan Beetch ◽  
Nicole M. Enright ◽  
Maurine Neiman

ABSTRACTThe proteins responsible for mitochondrial function are encoded by two different genomes with distinct inheritance regimes, rendering rigorous inference of genotype-phenotype connections intractable for all but a few model systems. Asexual organisms provide a powerful means for addressing these challenges because offspring produced without recombination inherit both nuclear and mitochondrial genomes from a single parent. As such, these offspring inherit mitonuclear genotypes that are identical to the mitonuclear genotypes of their parents and siblings and different from those of other asexual lineages. Here, we compared mitochondrial function across distinct asexual lineages of Potamopyrgus antipodarum, a New Zealand freshwater snail model for understanding the evolutionary consequences of asexuality. Our analyses revealed substantial phenotypic variation across asexual lineages at three levels of biological organization: mitogenomic, organellar, and organismal. These data demonstrate that different asexual lineages have different mitochondrial function phenotypes and that there exists heritable variation (that is, the raw material for evolution) for mitochondrial function in P. antipodarum. The discovery of this variation combined with the methods developed here sets the stage to use P. antipodarum to study central evolutionary questions involving mitochondrial function, including whether mitochondrial mutation accumulation influences the maintenance of sexual reproduction in natural populations.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 181-181
Author(s):  
Franziska Zúñiga ◽  
Magdalena Osinska ◽  
Franziska Zuniga

Abstract Quality indicators (QIs) are used internationally to measure, compare and improve quality in residential long-term care. Public reporting of such indicators allows transparency and motivates local quality improvement initiatives. However, little is known about the quality of QIs. In a systematic literature review, we assessed which countries publicly report health-related QIs, whether stakeholders were involved in their development and the evidence concerning their validity and reliability. Most information was found in grey literature, with nine countries (USA, Canada, Australia, New Zealand and five countries in Europe) publicly reporting a total of 66 QIs in areas like mobility, falls, pressure ulcers, continence, pain, weight loss, and physical restraint. While USA, Canada and New Zealand work with QIs from the Resident Assessment Instrument – Minimal Data Set (RAI-MDS), the other countries developed their own QIs. All countries involved stakeholders in some phase of the QI development. However, we only found reports from Canada and Australia on both, the criteria judged (e.g. relevance, influenceability), and the results of structured stakeholder surveys. Interrater reliability was measured for some RAI QIs and for those used in Germany, showing overall good Kappa values (>0.6) except for QIs concerning mobility, falls and urinary tract infection. Validity measures were only found for RAI QIs and were mostly moderate. Although a number of QIs are publicly reported and used for comparison and policy decisions, available evidence is still limited. We need broader and accessible evidence for a responsible use of QIs in public reporting.


1995 ◽  
Vol 6 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Isolde Ullmann ◽  
Peter Bannister ◽  
J. Bastow Wilson

2021 ◽  
Author(s):  
◽  
Ellen Yarrow

<p>This study explores the relationship between professional contractors and the permanent employees they work with at organisations in New Zealand. This thesis uses two concepts, organisational socialisation and the psychological contract, as lenses through which the working relationship is explored. The 20th century notion of standard employment has largely been eroded, giving way to different forms of non-standard work. Professional contractors are now found performing a variety of roles in many organisations across this country. Many are doing the work of permanent employees, but they are neither employees nor permanent. Professional contractors are a type of non-standard, transient worker. As part of a blended workforce, professional contractors work alongside permanent employees, but little is known about how they work together.  This qualitative study involves 49 face-to-face interviews with professional contractors, permanent employees and managers working in the Information Technology (IT) divisions of 10 organisations in three major cities in New Zealand. This research design results in a rich data set. The data collected was subject to analysis using the software NVIVO. This data was analysed in relation to the literature on organisational socialisation and the psychological contract to further explain the working relationship between professional contractors and permanent employees.  The findings reveal professional contractors’ experience of Van Maanen’s (1979) socialisation tactics were: collective, informal, variable, random and serial. It was found that an organisation’s policy sets the tone for the treatment (induction, inclusion and management) of professional contractors. According to the professional contractors interviewed, the Chao, O'Leary-Kelly, Wolf, Klein, and Gardner (1994) socialisation content dimensions that are important are structure, culture and values and language but history was not considered important. According to the managers interviewed, contractors need to know about the processes and procedures of the client organisation, have strong technical skills and industry, sector or domain knowledge. It was found that the indicator of adjustment ‘acceptance by insiders’ (Bauer & Erdogan, 2012) may be a sign that the contractor is adjusting to their new role but it is not essential. A new indicator of adjustment for professional contractors – output – clearly emerged from the data. The notion of ‘time to productivity’ is highly relevant to professional contractors and three factors affecting it are identified (contractor capability, role complexity and organisation readiness). Another important finding is that permanent employees play a key role as socialisation agents (Feldman, 1994; Jones, 1983; Van Maanen, 1978) in the socialisation of professional contractors. Surprisingly, it was found that other professional contractors also act as socialisation agents assisting the newcomer to adjust. It was found that proactive socialisation is particularly important for professional contractors. Together these findings establish the need to reconceptualise organisational socialisation for professional contractors specifically.  The second part of this thesis explores the psychological contract by asking interviewees about their mutual expectations. The expectations of each of the three parties (managers, professional contractors, and permanent employees) are subtly different, potentially influencing the psychological contract they develop. Permanent employees expect great things, professionalism and independence from professional contractors. Managers expect speed, professionalism and value for money from contractors. On the other hand, professional contractors simply expect to be treated with respect by their colleagues. Professional contractors expect to be given autonomy by their managers and support or guidance, should they require it. This study was not able to ascertain what type of psychological contract a professional contractor may develop. It is possible that a professional contractor develops a hybrid psychological contract. Alternatively, it is possible that a professional contractor’s psychological contract moves between the types developed by Rousseau (1995) over the course of their term with the client organisation. The insights gained by exploring the expectations of professional contractors, permanent employees and their managers are two-fold. Firstly, these expectations provide a valuable insight into the working relationship. Secondly, the exploration of a breach or violation of the psychological contract indicates that a malleable psychological contract (one that will shift or adjust) is less likely to manifest a breach or violation. Therefore, it is better for a professional contractor to develop and maintain a malleable rather than rigid psychological contract.  This study’s findings highlight the interrelationship between organisational socialisation and the psychological contract. This thesis asserts that the working relationship between professional contractors and permanent employees is specifically influenced by the socialisation of contractors as newcomers and in the mutual expectations, which form the psychological contract. As a result, it contributes to theorising and understanding of the working relationship between professional contractors and permanent employees. It identifies several tensions in the co-dependent working relationship, which are: time, team, treatment and training. This study has implications for Human Resource practitioners and managers because there is a need for corporate or HR policy relating to the treatment professional contractors. The use of organisational socialisation and the psychological contract as lenses with which the working relationship is explored is both original and meaningful.</p>


2022 ◽  
Author(s):  
Sanjay Kumar ◽  
Aaron Ramonett ◽  
Tasmia Ahmed ◽  
Euna Kwak ◽  
Paola Cruz Flores ◽  
...  

Mitochondrial remodeling is a fundamental process underlying cellular respiration and metabolism. Here we report TAK1 as a direct regulator of mitochondrial fusion. TAK1 is activated by a variety of mitogenic factors, cytokines and environmental stimuli, which we find induces rapid fragmentation through Mfn2 inactivation. TAK1 phosphorylates Mfn2 at Ser249, which inhibits the binding of GTP required for Mfn trans-dimerization and mitochondrial membrane fusion. Accordingly, expression of Mfn2-S249 phosphomimetics (Mfn2-E/D) constitutively promote fission whereas alanine mutant (Mfn2-A) yields hyperfused mitochondria and increased bioenergetics in cells. In mice, Mfn2-E knock-in yields embryonic lethality in homozygotes whereas heterozygotes are viable but exhibit increased visceral fat accumulation despite normal body weight and cognitive/motor functions compared to wildtype and Mfn2-A mice. Mature white adipocytes isolated from mutant mice reveal cell-autonomous TAK1-related effects on mitochondrial remodeling and lipid metabolism. These results identify Mfn2-S249 as a dynamic phosphoregulatory switch of mitochondrial fusion during development and energy homeostasis.


Behaviour ◽  
2017 ◽  
Vol 154 (9-10) ◽  
pp. 1029-1050 ◽  
Author(s):  
D.R. Johnston ◽  
W. Rayment ◽  
E. Slooten ◽  
S.M. Dawson

Photo-identification is an invaluable method for documenting associations. Based on the assumption that individuals photographed close together in time are physically close in space, the metadata associated with digital photography offers an opportunity to base association analyses on time between images. This was tested via analysis of associations within a population of bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand. We compared the widely used group-membership method and an alternative time-based method. Overall social structures between methods were similar; high degrees of association among all individuals and little support for sub-groups. Results also indicated an increase in the precision of pairwise indices for the time-based method. This study validated the approach of using time as a basis for analyses of associations. Importantly, this method can be retrospectively applied to any photo-ID data set in which images of uniquely identifiable individuals are time-stamped by the camera.


2019 ◽  
Vol 8 (3) ◽  
pp. e000490 ◽  
Author(s):  
Aidan Christopher Tan ◽  
Elizabeth Armstrong ◽  
Jacqueline Close ◽  
Ian Andrew Harris

ObjectivesThe value of a clinical quality registry is contingent on the quality of its data. This study aims to pilot methodology for data quality audits of the Australian and New Zealand Hip Fracture Registry, a clinical quality registry of hip fracture clinical care and secondary fracture prevention.MethodsA data quality audit was performed by independently replicating the data collection and entry process for 163 randomly selected patient records from three contributing hospitals, and then comparing the replicated data set to the registry data set. Data agreement, as a proxy indicator of data accuracy, and data completeness were assessed.ResultsAn overall data agreement of 82.3% and overall data completeness of 95.6% were found, reflecting a moderate level of data accuracy and a very high level of data completeness. Half of all data disagreements were caused by information discrepancies, a quarter by missing discrepancies and a quarter by time, date and number discrepancies. Transcription discrepancies only accounted for 1 in every 50 data disagreements. The sources of inaccurate and incomplete data have been identified with the intention of implementing data quality improvement.ConclusionsRegular audits of data abstraction are necessary to improve data quality, assure data validity and reliability and guarantee the integrity and credibility of registry outputs. A generic framework and model for data quality audits of clinical quality registries is proposed, consisting of a three-step data abstraction audit, registry coverage audit and four-step data quality improvement process. Factors to consider for data abstraction audits include: central, remote or local implementation; single-stage or multistage random sampling; absolute, proportional, combination or alternative sample size calculation; data quality indicators; regular or ad hoc frequency; and qualitative assessment.


Author(s):  
Bao-Linh Tran ◽  
Chi-Chung Chen ◽  
Wei-Chun Tseng ◽  
Shu-Yi Liao

This study examines how experience of severe acute respiratory syndrome (SARS) influences the impact of coronavirus disease (COVID-19) on international tourism demand for four Asia-Pacific Economic Cooperation (APEC) economies, Taiwan, Hong Kong, Thailand, and New Zealand, over the 1 January–30 April 2020 period. To proceed, panel regression models are first applied with a time-lag effect to estimate the general effects of COVID-19 on daily tourist arrivals. In turn, the data set is decomposed into two nation groups and fixed effects models are employed for addressing the comparison of the pandemic-tourism relationship between economies with and without experiences of the SARS epidemic. Specifically, Taiwan and Hong Kong are grouped as economies with SARS experiences, while Thailand and New Zealand are grouped as countries without experiences of SARS. The estimation result indicates that the number of confirmed COVID-19 cases has a significant negative impact on tourism demand, in which a 1% COVID-19 case increase causes a 0.075% decline in tourist arrivals, which is a decline of approximately 110 arrivals for every additional person infected by the coronavirus. The negative impact of COVID-19 on tourist arrivals for Thailand and New Zealand is found much stronger than for Taiwan and Hong Kong. In particular, the number of tourist arrivals to Taiwan and Hong Kong decreased by 0.034% in response to a 1% increase in COVID-19 confirmed cases, while in Thailand and New Zealand, a 1% national confirmed cases increase caused a 0.103% reduction in tourism demand. Moreover, the effect of the number of domestic cases on international tourism is found lower than the effect caused by global COVID-19 mortality for the economies with SARS experiences. In contrast, tourist arrivals are majorly affected by the number of confirmed COVID-19 cases in Thailand and New Zealand. Finally, travel restriction in all cases is found to be the most influencing factor for the number of tourist arrivals. Besides contributing to the existing literature focusing on the knowledge regarding the nexus between tourism and COVID-19, the paper’s findings also highlight the importance of risk perception and the need of transmission prevention and control of the epidemic for the tourism sector.


2019 ◽  
Vol 30 (24) ◽  
pp. 2943-2952 ◽  
Author(s):  
Enrique J. Garcia ◽  
Janeska J. de Jonge ◽  
Pin-Chao Liao ◽  
Elizabeth Stivison ◽  
Cierra N. Sing ◽  
...  

Loss of mitochondrial DNA (mtDNA) results in loss of mitochondrial respiratory activity, checkpoint-regulated inhibition of cell cycle progression, defects in growth, and nuclear genome instability. However, after several generations, yeast cells can adapt to the loss of mtDNA. During this adaptation, rho0 cells, which have no mtDNA, exhibit increased growth rates and nuclear genome stabilization. Here, we report that an immediate response to loss of mtDNA is a decrease in replicative lifespan (RLS). Moreover, we find that adapted rho0 cells bypass the mtDNA inheritance checkpoint, exhibit increased mitochondrial function, and undergo an increase in RLS as they adapt to the loss of mtDNA. Transcriptome analysis reveals that metabolic reprogramming to compensate for defects in mitochondrial function is an early event during adaptation and that up-regulation of stress response genes occurs later in the adaptation process. We also find that specific subtelomeric genes are silenced during adaptation to loss of mtDNA. Moreover, we find that deletion of SIR3, a subtelomeric gene silencing protein, inhibits silencing of subtelomeric genes associated with adaptation to loss of mtDNA, as well as adaptation-associated increases in mitochondrial function and RLS extension.


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