A field-compatible method for measuring alternative respiratory pathway activities in vivo using stable O2 isotopes.

Plants can alter rates of electron transport through the alternative oxidase (AOX) pathway in response to environmental cues, thus modulating respiratory efficiency, but the (18)O discrimination method necessary for measuring electron partitioning in vivo has been restricted to laboratory settings. To overcome this limitation, we developed a field-compatible analytical method. Series of plant tissue subsamples were incubated in 12 mL septum-capped vials for 0.5-4 h before aliquots of incubation air were injected into 3.7 mL evacuated storage vials. Vials were stored for up to 10 months before analysis by mass spectrometry. Measurements were corrected for unavoidable contamination. Additional mathematical tools were developed for detecting and addressing non-linearity (whether intrinsic or due to contamination) in the data used to estimate discrimination values. Initial contamination in the storage vials was 0.03 ± 0.01 atm; storing the gas samples at -17 °C eliminated further contamination effects over 10 months. Discrimination values obtained using our offline incubation and computation method replicated previously reported results over a range of 10-31‰, with precision generally better than ±0.5‰. Our method enables large-scale investigations of plant alternative respiration along natural environmental gradients under field conditions.

Improving patient understanding and outcomes in myelodysplastic syndromes - An animated patient guide to MDS with visual formats of learning.

Objectives: Patient education resources that address barriers to health literacy to improve understanding and outcomes in myelodysplastic syndromes (MDS) are limited. The aim of this study was to evaluate the impact and outcomes benefits of An Animated Patient's Guide to Myelodysplastic Syndromes (MDS) cancer educational modules (which includes the 'You and MDS' website and YouTube hosted resources) related to MDS education, awareness, understanding and health outcomes. Methods: This was a retrospective study of learner feedback, metrics, and utilization data from July 2018 to August 2021. We evaluated audience reach (number of visit sessions, unique visitors, page views) and calculated top views by media type (animation, expert video, patient video, and slide show) and top retention videos from the modules. We also assessed the educational impact and utilization through learner feedback surveys. Results: During the study period, 'You and MDS' had 233,743 views worldwide of which 104,214 were unique visitors and 78,161 (or 76% unique visitors) were from the United States. Of these, 61% were patients; 29% family members or caregivers; 5% were healthcare providers and 5% represented other groups. Most popular topics viewed among the animations were "Understanding Myelodysplastic Syndromes (MDS)" (40,219 views), "Managing and Treating MDS" (19,240 views), "Understanding Erythropoiesis" (17,564 views.) The most popular expert videos viewed were "What is iron overload, and how it is treated?" (20,310 views), "How serious a cancer is MDS? What is the prognosis for MDS?" (8,327 views), "What is MDS?" (3,157 views). Of participants who completed the online feedback survey, ≥ 95% reported improved knowledge gains and commitments to change. Conclusions: MDS patients using 'You and MDS - An Animated Patient's Guide to MDS' and its visual formats of learning represented a wide U.S. and global learner audience. This MDS educational resource had a significant impact on improved understanding among patients, families, and caregivers. Continued efforts should be made to provide patient-effective resources that address health literacy, improve patient understanding, and address educational needs that respond to the concerns of patients to achieve better quality of life and improved health outcomes in MDS.

Leaf respiration and alternative oxidase in field-grown alpine grasses respond to natural changes in temperature and light.

• We report the first investigation of changes in electron partitioning via the alternative respiratory pathway (AP) and alternative oxidase (AOX) protein abundance in field-grown plants and their role in seasonal acclimation of respiration. • We sampled two alpine grasses native to New Zealand, Chionochloa rubra and Chionochloa pallens, from field sites of different altitudes, over 1 yr and also intensively over a 2-wk period. • In both species, respiration acclimated to seasonal changes in temperature through changes in basal capacity (R10) but not temperature sensitivity (E0). In C. pallens, acclimation of respiration may be associated with a higher AOX : cytochrome c oxidase (COX) protein abundance ratio. Oxygen isotope discrimination (D), which reflects relative changes in AP electron partitioning, correlated positively with daily integrated photosynthetically active radiation (PAR) in both species over seasonal timescales. Respiratory parameters, the AOX : COX protein ratio and D were stable over a 2-wk period, during which significant temperature changes were experienced in the field. • We conclude that respiration in Chionochloa spp. acclimates strongly to seasonal, but not to short-term, temperature variation. Alternative oxidase appears to be involved in the plant response to both seasonal changes in temperature and daily changes in light, highlighting the complexity of the function of AOX in the field.

Seasonal variation of leaf respiration and the alternative pathway in field-grown Populus × canadensis.

The temperature response of plant respiration varies between species and can acclimate to changing temperatures. Mitochondrial respiration in plants has two terminal oxidases: the cytochrome c oxidase (COX) and the cyanide-resistant alternative oxidase (AOX). In Populus × canadensis var. italica, a deciduous tree species, we investigated the temperature response of leaf respiration via the alternative and cytochrome pathways, as well as seasonal changes in these pathways, using the oxygen isotope fractionation technique. The electron partitioning through the alternative pathway (τ(a) ) increased from 0 to 30-40% with measurement temperatures from 6 to 30°C at all times measured throughout the growing season. τ(a) at the growth temperature (the average temperature during 3 days prior to sampling) increased from 12 to 29% from spring until late summer and decreased thereafter. Total respiration declined throughout the growing season by 50%, concomitantly with decreases in both AOX (64%) and COX (32%) protein abundances. Our results provide new insight into the natural variability of AOX protein abundances and alternative respiration electron partitioning over immediate and seasonal timescales.

The Glaring Gender Bias in the Operating Room: A Qualitative Study of Factors Influencing Career Selection for First-Year Medical Students.

OBJECTIVE: Despite greater female than male-identifying Canadian medical graduates, women continued to be underrepresented in surgical specialties. The aim of this study was to explore the role of lifestyle challenges and gender-specific considerations in career selection for first-year medical students following early exposure to surgery through an immersive surgical program. DESIGN: A single institution, qualitative study consisting of structured focus groups before and after completion of a 2-week surgical program was used to explore medical student perceptions of surgery. The program consisted of shadowing, surgeon-led talks, and surgical skills workshops in all direct-entry surgical specialties within the Department of Surgery at the University of Toronto. Six entry and exit interviews were conducted by 2 authors. Interviews were recorded, transcribed, and coded for thematic analysis. SETTING: Teaching hospitals affiliated with the University of Toronto, Canada PARTICIPANTS: Thirty first-year medical students with interest in surgery participated in the program and the focus groups. RESULTS: Four prominent themes emerged: gender imbalances in the work environment, the importance of female mentors, gender-specific challenges of parenting, and the importance of flexible work hours for both male and female students. Greater exposure to female surgeons improved the outlook of medical students on work-life balance. Medical students are concerned with the challenges of pregnancy in a surgical profession. Both male and female students consider parenting, supportive partners, and flexibility of work hours in their career selection. CONCLUSION: This study demonstrates the prevalence of gender bias in surgical specialties, raising gender-specific challenges that impact career selection for first-year medical students. In an effort to address these perceptions, this study supports efforts to implement formalized mentorship programs for women in surgery early in medical education. Furthermore, concerns surrounding childbearing further support the need for well-established parental leave policies in the Canadian postgraduate medical education system.

Urban environment of New York City promotes growth in northern red oak seedlings.

Urbanization is accelerating across the globe, elevating the importance of studying urban ecology. Urban environments exhibit several factors affecting plant growth and function, including high temperatures (particularly at night), CO(2) concentrations and atmospheric nitrogen deposition. We investigated the effects of urban environments on growth in Quercus rubra L. seedlings. We grew seedlings from acorns for one season at four sites along an urban-rural transect from Central Park in New York City to the Catskill Mountains in upstate New York (difference in average maximum temperatures of 2.4 °C; difference in minimum temperatures of 4.6 °C). In addition, we grew Q. rubra seedlings in growth cabinets (GCs) mimicking the seasonal differential between the city and rural sites (based on a 5-year average). In the field experiment, we found an eightfold increase in biomass in urban-grown seedlings relative to those grown at rural sites. This difference was primarily related to changes in growth allocation. Urban-grown seedlings and seedlings grown at urban temperatures in the GCs exhibited a lower root: shoot ratio (urban ~0.8, rural/remote ~1.5), reducing below-ground carbon costs associated with construction and maintenance. These urban seedlings instead allocated more growth to leaves than did rural-grown seedlings, resulting in 10-fold greater photosynthetic area but no difference in photosynthetic capacity of foliage per unit area. Seedlings grown at urban temperatures in both the field and GC experiments had higher leaf nitrogen concentrations per unit area than those grown at cooler temperatures (increases of 23% in field, 32% in GC). Lastly, we measured threefold greater (13)C enrichment of respired CO(2) (relative to substrate) in urban-grown leaves than at other sites, which may suggest greater allocation of respiratory function to growth over maintenance. It also shows that lack of differences in total R flux in response to environmental conditions may mask dramatic shifts in respiratory functioning. Overall, our findings indicating greater seedling growth and establishment at a critical regeneration phase of forest development may have important implications for the ecology of urban forests as well as the predicted growth of the terrestrial biosphere in temperate regions in response to climate change.