Coexpression-based clustering of Arabidopsis root genes predicts functional modules in early phosphate deficiency signaling.

Phosphate (Pi) deficiency triggers the differential expression of a large set of genes, which communally adapt the plant to low Pi bioavailability. To infer functional modules in early transcriptional responses to Pi deficiency, we conducted time-course microarray experiments and subsequent coexpression-based clustering of Pi-responsive genes by pairwise comparison of genes against a customized database. Three major clusters, enriched in genes putatively functioning in transcriptional regulation, root hair formation, and developmental adaptations, were predicted from this analysis. Validation of gene expression by quantitative reverse transcription-PCR revealed that transcripts from randomly selected genes were robustly induced within the first hour after transfer to Pi-deplete medium. Pectin-related processes were among the earliest and most robust responses to Pi deficiency, indicating that cell wall alterations are critical in the early transcriptional response to Pi deficiency. Phenotypical analysis of homozygous mutants defective in the expression of genes from the root hair cluster revealed eight novel genes involved in Pi deficiency-induced root hair elongation. The plants responded rapidly to Pi deficiency by the induction of a subset of transcription factors, followed by a repression of genes involved in cell wall alterations. The combined results provide a novel, integrated view at a systems level of the root responses that acclimate Arabidopsis (Arabidopsis thaliana) to suboptimal Pi levels.

All clinical stressors are not created equal: Differential task stress in a simulated clinical environment.

Background: A variety of stressors are encountered while working in the emergency department and are often recreated in simulation-based medical education. We seek to examine the physiologic and stress state response of participants in a simulated clinical environment to commonly encountered stressors. Methods: Emergency medicine (EM) residents participated in a randomized, controlled trial of six simulated patient encounters with one of three stressors, medical difficulty, interpersonal challenge, and technology/equipment failure, randomized into each scenario. Participants wore smart shirts to measure heart rate variability (HRV) at rest and just after the introduced stressor and completed the Short Stress State Questionnaire (SSSQ) before and after each scenario. Results: Twenty-seven EM residents participated in the study. Interpersonal challenge resulted in increased distress as measured by SSSQ compared to the other two stressors (one way ANOVA, F[2,144] = 9.95, p < 0.001). There was no difference in worry or task engagement across stressors. HRV decreased significantly from rest for all stressors (p = 0.0003, p = 0.0112, p = 0.0027 for medical difficulty, interpersonal challenge, and equipment failure, respectively), but there was no statistically significant difference between mean change in HRV across stressors (one way ANOVA, F[2,120] = 0.17, p = 0.8452). Conclusions: Interpersonal challenge stressor was significantly associated with an increase in distress in EM residents during the simulated encounters as compared to the other stressors. While heart rate variability decreased from rest for each stressor as expected following stressor introduction, differing stressors did not produce a differential change.

Transcriptional profiling of the Arabidopsis iron deficiency response reveals conserved transition metal homeostasis networks.

Iron (Fe) deficiency is counteracted by a suite of responses to ensure maintenance of vital processes for which Fe is essential. Here, we report on transcriptional changes upon Fe deficiency, investigated in two Arabidopsis (Arabidopsis thaliana) accessions, Columbia (Col-0) and C24. Functional modules of the Arabidopsis Fe deficiency syndrome were inferred from clustering of Fe-responsive genes according to their coexpression. It was found that the redistribution of transition metals is an integral part of the reduction-based response to Fe starvation. The differential expression of metal transporters under the control of the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR appeared to reflect an anticipated reaction rather than a response to the actual change in metal distribution. In contrast, the regulation of the zinc transporters ZRT/IRT-LIKE PROTEIN2 (ZIP2), ZIP3, ZIP4, and ZIP9 was dependent on the cellular zinc level, and their regulation by Fe was a secondary effect. Cellular Fe homeostasis was found to be closely coupled to Fe-related processes in the plastids. Using clustered genes as bait in gene-fishing experiments, we were able to attribute potentially important roles for gene candidates that have no previously described function in the Fe deficiency response. These results demonstrate a conceptually novel and integrative view into the regulation and interactions that allow Arabidopsis to adapt to suboptimal Fe availability.

Eclampsia.

Audience: Emergency medicine residents. Introduction: Eclampsia is the development of a generalized seizure in pregnant patients with hypertension of pregnancy.1 Eclampsia exists on the spectrum of hypertension-related disorders in pregnancy, occurs in 1 out of 1,000-10,000 deliveries,1-3and is associated with significant maternal and fetal morbidity and mortality.4 Given the emergent nature of eclampsia and the benefit of rapid treatment, emergency medicine (EM) physicians need to quickly recognize and treat this rare pathology. Although residents have three to four years before becoming an attending, not all emergent pathologies may present clinically during their training. It is important to simulate rare, treatable conditions such as eclampsia to give learners exposure confidence in managing this disease. Educational Objectives: By the end of this simulation session, learners will be able to:Demonstrate care of a gravid patient with altered mental statusDemonstrate care of a gravid patient with seizuresRecognize care involved in assessment of fetal statusExecute appropriate subspecialty consultationRecognize the clinical signs and symptoms of eclampsiaDistinguish different treatment options for eclampsiaIdentify magnesium toxicity and reversal agentDifferentiate the spectrum of preeclampsia. Educational Methods: As an educational strategy, simulation allows learners to partake in experiential learning. By creating a safe and supportive learning environment, simulation allows learners to facilitate deliberate practice and transfer learning in debriefing sessions. High-fidelity sessions involve software and technology to mimic realistic patient environments, which also activate learners' affective states to aid in decision-making abilities in complex medical cases.This session was conducted using a high-fidelity mannequin, SimMom (Laerdal), and a controlling Laerdal LLEAP Software. Faculty-led debriefing followed the simulation case and included discussion regarding presentation, spectrum, and management of the obstetrical emergency.5. Research Methods: Resident participants completed an evaluation form consisting of questions on a 5-point Likert scale assessing the realism and usefulness of the simulation. Results: All 18 residents who participated in the simulation completed an evaluation form, and all agreed or strongly agreed the case was realistic and useful. Discussion: Incorporating high-stakes, low-frequency presentations through simulation can be readily applied in residency education and well-received by residents. Increasing the difficulty through adjusting the clinical history and exam may challenge learners further. Topics: Medical simulation, eclampsia, pregnancy, obstetrics, emergency medicine.

Virtual Telesimulation for Medical Students During the COVID-19 Pandemic.

PROBLEM: In March 2020, the novel coronavirus 2019 (COVID-19) became a global pandemic. Medical schools around the United States faced difficult decisions, temporarily suspending hospital-based clerkship rotations for medical students due to potential shortages of personal protective equipment and a need to social distance. This decision created a need for innovative, virtual learning opportunities to support undergraduate medical education. APPROACH: Educators at Yale School of Medicine developed a novel medical student curriculum converting high-fidelity, mannequin-based simulation into a fully online virtual telesimulation format. By using a virtual videoconferencing platform to deliver remote telesimulation as an immersive educational experience for widely dispersed students, this novel technology retains the experiential strengths of simulation-based learning while complying with needs for social distancing during the pandemic. The curriculum comprises simulated clinical scenarios that include live patient actors; facilitator interactions; and real-time assessment of vital signs, labs, and imaging. Each 90-minute session includes 2 sets of simulation scenarios and faculty-led teledebriefs. A team of 3 students performs the first scenario, while an additional team of 3 students observes. Teams reverse roles for the second scenario. OUTCOMES: The 6-week virtual telesimulation elective enrolled the maximum 48 medical students and covered core clinical clerkship content areas. Communication patterns within the virtual telesimulation format required more deliberate turn-taking than normal conversation. Using the chat function within the videoconferencing platform allowed teams to complete simultaneous tasks. A nurse confederate provided cues not available in the virtual telesimulation format. NEXT STEPS: Rapid dissemination of this program, including online webinars and live demonstration sessions with student volunteers, supports the development of similar programs at other universities. Evaluation and process improvement efforts include planned qualitative evaluation of this new format to further understand and refine the learning experience. Future work is needed to evaluate clinical skill development in this educational modality.

A molecular and structural characterization of senescing Arabidopsis siliques and comparison of transcriptional profiles with senescing petals and leaves.

Senescence of plant organs is a genetically controlled process that regulates cell death to facilitate nutrient recovery and recycling, and frequently precedes, or is concomitant with, ripening of reproductive structures. In Arabidopsis thaliana, the seeds are contained within a silique, which is itself a photosynthetic organ in the early stages of development and undergoes a programme of senescence prior to dehiscence. A transcriptional analysis of the silique wall was undertaken to identify changes in gene expression during senescence and to correlate these events with ultrastructural changes. The study revealed that the most highly up-regulated genes in senescing silique wall tissues encoded seed storage proteins, and the significance of this finding is discussed. Global transcription profiles of senescing siliques were compared with those from senescing Arabidopsis leaf or petal tissues using microarray datasets and metabolic pathway analysis software (MapMan). In all three tissues, members of NAC and WRKY transcription factor families were up-regulated, but components of the shikimate and cell-wall biosynthetic pathways were down-regulated during senescence. Expression of genes encoding ethylene biosynthesis and action showed more similarity between senescing siliques and petals than between senescing siliques and leaves. Genes involved in autophagy were highly expressed in the late stages of death of all plant tissues studied, but not always during the preceding remobilization phase of senescence. Analyses showed that, during senescence, silique wall tissues exhibited more transcriptional features in common with petals than with leaves. The shared and distinct regulatory events associated with senescence in the three organs are evaluated and discussed.

An Interprofessional Simulation-Based Orientation Program for Transitioning Novice Nurses to Critical Care Roles in the Emergency Department: Pilot Implementation and Evaluation.

BACKGROUND: The emergency department (ED) relies on high-functioning teams to deliver consistent and safe patient care. Experts recommend that both emergency physicians and ED nurses participate in team training. However, there are currently no nationally accepted curricula for either profession to embed this training in their professional development, particularly for health workers who are novice or transitioning into critical care roles. METHODS: An interprofessional educator team designed and embedded a series of simulation scenarios within a novel orientation program for novice nurses transitioning to critical care roles in the ED to teach clinical and teamwork skills for conjoint groups of resident physician and novice nurse learners. The team created four interprofessional simulations to represent the acuity and breadth of patient populations in the ED critical care bays. INTERVENTION/REFINEMENT: To date, the team has conducted 24 two-week orientation sessions for 48 nurses and 51 resident physicians. Overall mean scores for the Debriefing Assessment for Simulation in Healthcare (DASH) instrument from nursing participants in the first 18 sessions were high. Qualitative evaluation data from both nurses and physicians demonstrated a positive impact of the simulations and provided insight into respective roles, identities, and priorities across professions. Participant feedback led to iterative steps in refinement of the simulations, including adjustments in debriefings and logistics of the orientation program. IMPLICATIONS FOR PRACTICE: A team-based interprofessional simulation program was found to be feasible and acceptable for practicing novice physicians and nurses as part of a nursing critical care orientation program in the ED. Future work will assess the program's long-term impact on teamwork and safety in the actual clinical environment.

Early iron-deficiency-induced transcriptional changes in Arabidopsis roots as revealed by microarray analyses.

BACKGROUND: Iron (Fe) is an essential nutrient in plants and animals, and Fe deficiency results in decreased vitality and performance. Due to limited bio-availability of Fe, plants have evolved sophisticated adaptive alterations in development, biochemistry and metabolism that are mainly regulated at the transcriptional level. We have investigated the early transcriptional response to Fe deficiency in roots of the model plant Arabidopsis, using a hydroponic system that permitted removal of Fe from the nutrient solution within seconds and transferring large numbers of plants with little or no mechanical damage to the root systems. We feel that this experimental approach offers significant advantages over previous and recent DNA microarray investigations of the Fe-deficiency response by increasing the resolution of the temporal response and by decreasing non-Fe deficiency-induced transcriptional changes, which are common in microarray analyses. RESULTS: The expression of sixty genes were changed after 6 h of Fe deficiency and 65% of these were found to overlap with a group of seventy-nine genes that were altered after 24 h. A disproportionally high number of transcripts encoding ion transport proteins were found, which function to increase the Fe concentration and decrease the zinc (Zn) concentration in the cytosol. Analysis of global changes in gene expression revealed that changes in Fe availability were associated with the differential expression of genes that encode transporters with presumed function in uptake and distribution of transition metals other than Fe. It appeared that under conditions of Fe deficiency, the capacity for Zn uptake increased, most probably the result of low specificity of the Fe transporter IRT1 that was induced upon Fe deficiency. The transcriptional regulation of several Zn transports under Fe deficiency led presumably to the homeostatic regulation of the cytosolic concentration of Zn and of other transition metal ions such as Mn to avoid toxicity. CONCLUSION: The genomic information obtained from this study gives insights into the rapid transcriptional responses to Fe shortage in plants, and is important for understanding how changes in nutrient availability are translated into responses that help to avoid imbalances in ion distribution. We further identified rapidly induced or repressed genes with potential roles in perception and signaling during Fe deficiency which may aid in the elucidation of these processes.

Positional signaling and expression of ENHANCER OF TRY AND CPC1 are tuned to increase root hair density in response to phosphate deficiency in Arabidopsis thaliana.

Phosphate (Pi) deficiency induces a multitude of responses aimed at improving the acquisition of Pi, including an increased density of root hairs. To understand the mechanisms involved in Pi deficiency-induced alterations of the root hair phenotype in Arabidopsis (Arabidopsis thaliana), we analyzed the patterning and length of root epidermal cells under control and Pi-deficient conditions in wild-type plants and in four mutants defective in the expression of master regulators of cell fate, CAPRICE (CPC), ENHANCER OF TRY AND CPC 1 (ETC1), WEREWOLF (WER) and SCRAMBLED (SCM). From this analysis we deduced that the longitudinal cell length of root epidermal cells is dependent on the correct perception of a positional signal ('cortical bias') in both control and Pi-deficient plants; mutants defective in the receptor of the signal, SCM, produced short cells characteristic of root hair-forming cells (trichoblasts). Simulating the effect of cortical bias on the time-evolving probability of cell fate supports a scenario in which a compromised positional signal delays the time point at which non-hair cells opt out the default trichoblast pathway, resulting in short, trichoblast-like non-hair cells. Collectively, our data show that Pi-deficient plants increase root hair density by the formation of shorter cells, resulting in a higher frequency of hairs per unit root length, and additional trichoblast cell fate assignment via increased expression of ETC1.