Publications by authors named "A Harvey Millar"

1,016 Publications

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Knockdown of Succinate Dehydrogenase Assembly Factor 2 Induces Reactive Oxygen Species-Mediated Auxin Hypersensitivity Causing pH-dependent Root Elongation.

Plant Cell Physiol 2021 May 21. Epub 2021 May 21.

ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.

Metabolism, auxin signalling and ROS all contribute to plant growth and each is linked to plant mitochondria and the process of respiration. Knockdown of mitochondrial Succinate Dehydrogenase Assembly Factor 2 (SDHAF2) in Arabidopsis thaliana, lowered succinate dehydrogenase activity and led to pH-inducible root inhibition when the growth medium pH was poised at different points between 7.0 and 5.0, but this phenomenon was not observed in WT. Roots of sdhaf2 mutants showed high accumulation of succinate, depletion of citrate and malate and up-regulation of ROS-related and stress-inducible genes at pH 5.5. A change of oxidative status in sdhaf2 roots at low pH was also evidenced by low ROS staining in root tips and altered root sensitivity to H2O2. sdhaf2 had low auxin activity in root tips via DR5-GUS staining, but displayed increased IAA (auxin) abundance and IAA hypersensitivity, which is most likely caused by the change in ROS levels. On this basis we conclude that knockdown of SDHAF2 induces pH-related root elongation and auxin hyperaccumulation and hypersensitivity, mediated by altered ROS homeostasis. This observation extends the existing evidence of associations between mitochondrial function and auxin by establishing a cascade of cellular events that link them through ROS formation, metabolism and root growth at different pH values.
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http://dx.doi.org/10.1093/pcp/pcab061DOI Listing
May 2021

All Hands on Deck: Addressing Adolescent Depression in Pediatric Primary Care.

J Pediatr Psychol 2021 May 19. Epub 2021 May 19.

Children's Hospital Colorado.

Objective: This study examines prevalence rates of elevated depression symptoms utilizing the Patient Health Questionnaire-9 Item Modified for Adolescents (PHQ-9A), characterizes recommendations and interventions by primary care providers (PCPs) and behavioral health clinicians (BHCs) in response to elevated PHQ-9As, and identifies factors associated with improved PHQ-9A scores at follow-up pediatric primary care visits.

Methods: A mixed methods approach was taken. Visit data, demographics, and PHQ-9A scores for 2,107 adolescents aged 11-18 were extracted using clinical informatics between January 3, 2017 and August 31, 2018. Descriptive statistics and chi-square analyses were conducted, followed by conventional content analysis of electronic medical records to examine qualitative results. Qualitative analyses were transformed into quantitative results and analyzed using point biserial correlations.

Results: Of the 2,107 adolescents, 277 (13%) had an elevated PHQ-9A. Content analysis resulted in 40 actions (17 PCP codes, 23 BHC codes) in response to an elevated PHQ-9A. Significant correlations were found between an improved PHQ-9A at a follow-up visit and the PCP referring to integrated behavioral health (r = .20, p < .01), and BHCs recommending and checking in at a follow-up visit (r = .20, p < .05), conducting a risk assessment (r = .15, p < .05), and providing psychoeducation about mood symptoms (r = .15, p < .05).

Conclusions: Primary care is an ideal setting to address the public health crisis of untreated adolescent depression. Implications for screening processes, practice implications for PCPs and BHCs, future directions, and limitations are discussed.
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http://dx.doi.org/10.1093/jpepsy/jsab033DOI Listing
May 2021

Increased Wheat Protein Content via Introgression of an HMW Glutenin Selectively Reshapes the Grain Proteome.

Mol Cell Proteomics 2021 May 14;20:100097. Epub 2021 May 14.

ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia, Australia; School of Molecular Science, University of Western Australia, Crawley, Western Australia, Australia. Electronic address:

Introgression of a high-molecular-weight glutenin subunit (HMW-GS) allele, 1Ay21∗, into commercial wheat cultivars increased overall grain protein content and bread-making quality, but the role of proteins beyond this HMW-GS itself was unknown. In addition to increased abundance of 1Ay HMW-GS, 115 differentially accumulated proteins (DAPs) were discovered between three cultivars and corresponding introgressed near-isogenic lines. Functional category analysis showed that the DAPs were predominantly other storage proteins and proteins involved in protein synthesis, protein folding, protein degradation, stress response, and grain development. Nearly half the genes encoding the DAPs showed strong coexpression patterns during grain development. Promoters of these genes are enriched in elements associated with transcription initiation and light response, indicating a potential connection between these cis-elements and grain protein accumulation. A model of how this HMW-GS enhances the abundance of machinery for protein synthesis and maturation during grain filling is proposed. This analysis not only provides insights into how introgression of the 1Ay21∗ improves grain protein content but also directs selection of protein candidates for future wheat quality breeding programs.
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http://dx.doi.org/10.1016/j.mcpro.2021.100097DOI Listing
May 2021

A role for cardiopulmonary exercise testing in detecting physiological changes underlying health status in Idiopathic pulmonary fibrosis: a feasibility study.

BMC Pulm Med 2021 May 5;21(1):147. Epub 2021 May 5.

Academic Respiratory Unit, School of Clinical Sciences, Southmead Hospital, University of Bristol, Learning and Research Building, Bristol, BS10 5NB, UK.

Introduction: There is limited data available on the use of CPET as a predictive tool for disease outcomes in the setting of IPF. We investigated the feasibility of undertaking CPET and the relationship between CPET and quality of life measurements in a well-defined population of mild and moderate IPF patients.

Methods: A prospective, single-centre observational study.

Results: Thirty-two IPF patients (mild n = 23, moderate n = 9) participated in the study, n = 13 mild patients attended for repeat CPET testing at 12 months. At baseline, total K-BILD scores and total IPF-PROM scores significantly correlated with 6MWT distance, but not with baseline FVC % predicted, TLco % predicted, baseline or minimum SpO. VO peak/kg at AT positively correlated with total scores, breathlessness/activity and chest domains of the K-BILD questionnaire (p < 0.05). VO peak significantly correlated with total IPF PROM scores and wellbeing domains (p < 0.05), with a trend towards statistical significance for total IPF-PROM and VO peak/kg at anaerobic threshold (p = 0.06). There was a statistically significant reduction in FVC% predicted at 12 months follow up, although the mean absolute decline was < 10% (p < 0.05). During this period VO peak significantly reduced (21.6 ml/kg/min ± 2.9 vs 19.1 ± 2.8; p = 0.017), with corresponding reductions in total K-BILD and breathlessness/activity domains that exceeded the MCID for responsiveness. Lower baseline VO peak/kg at anaerobic threshold correlated with greater declines in total K-BILD scores (r =  - 0.62, 0.024) at 12 months. Whilst baseline FVC% predicted or TLco % predicted did not predict change in health status, CONCLUSION: We have shown that it is feasible to undertake CPET in patients with mild to moderate IPF. CPET measures of VO peak correlated with both baseline and change in K-BILD measurements at 1 year, despite relatively stable standard lung function (declines of < 10% in FVC), suggesting its potential sensitivity to detect physiological changes underlying health status.
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http://dx.doi.org/10.1186/s12890-021-01520-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8097115PMC
May 2021

Systems biology for crop improvement.

Plant Genome 2021 May 5:e20098. Epub 2021 May 5.

Center of Excellence in Genomics & Systems Biology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad, 502 324, India.

In recent years, generation of large-scale data from genome, transcriptome, proteome, metabolome, epigenome, and others, has become routine in several plant species. Most of these datasets in different crop species, however, were studied independently and as a result, full insight could not be gained on the molecular basis of complex traits and biological networks. A systems biology approach involving integration of multiple omics data, modeling, and prediction of the cellular functions is required to understand the flow of biological information that underlies complex traits. In this context, systems biology with multiomics data integration is crucial and allows a holistic understanding of the dynamic system with the different levels of biological organization interacting with external environment for a phenotypic expression. Here, we present recent progress made in the area of various omics studies-integrative and systems biology approaches with a special focus on application to crop improvement. We have also discussed the challenges and opportunities in multiomics data integration, modeling, and understanding of the biology of complex traits underpinning yield and stress tolerance in major cereals and legumes.
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http://dx.doi.org/10.1002/tpg2.20098DOI Listing
May 2021