Transcript profiling of mutants reveals that chloroplast singlet oxygen signals lead to global changes in RNA profiles and are mediated by Plant U-Box 4.

Background: In response to environmental stresses, chloroplasts generate reactive oxygen species, including singlet oxygen (O), an excited state of oxygen that regulates chloroplast-to-nucleus (retrograde) signaling, chloroplast turnover, and programmed cell death (PCD). Yet, the central signaling mechanisms and downstream responses remain poorly understood. The () mutant conditionally accumulates O and Plant U-Box 4 (PUB4), a cytoplasmic E3 ubiquitin ligase, is involved in propagating O signals for chloroplast turnover and cellular degradation.

Investigating the mechanism of chloroplast singlet oxygen signaling in the mutant.

As sessile organisms, plants have evolved complex signaling mechanisms to sense stress and acclimate. This includes the use of reactive oxygen species (ROS) generated during dysfunctional photosynthesis to initiate signaling. One such ROS, singlet oxygen (O), can trigger retrograde signaling, chloroplast degradation, and programmed cell death.

A genetic screen for dominant chloroplast reactive oxygen species signaling mutants reveals life stage-specific singlet oxygen signaling networks.

Introduction: Plants employ intricate molecular mechanisms to respond to abiotic stresses, which often lead to the accumulation of reactive oxygen species (ROS) within organelles such as chloroplasts. Such ROS can produce stress signals that regulate cellular response mechanisms. One ROS, singlet oxygen (O), is predominantly produced in the chloroplast during photosynthesis and can trigger chloroplast degradation, programmed cell death (PCD), and retrograde (organelle-to-nucleus) signaling.

A machine learning framework for optimizing obesity care by simulating clinical trajectories and targeted interventions.

Objective: This study aimed to determine the important clinical management bottlenecks that contribute to underuse of weight loss surgery (WLS) and assess risk factors for attrition at each of them.

Methods: A multistate conceptual model of progression from primary care to WLS was developed and used to study all adults who were seen by a primary care provider (PCP) and eligible for WLS from 2016 to 2017 at a large institution. Outcomes were progression from each state to each subsequent state in the model: PCP visit, endocrine weight management referral, endocrine weight management visit, WLS referral, WLS visit, and WLS.

Uncovering the brain-wide pattern of synaptic input to vasopressin-expressing neurons in the paraventricular nucleus of the hypothalamus.

Arginine vasopressin (AVP) is a neuropeptide critical for the mammalian stress response and social behavior. AVP produced in the hypothalamus regulates water osmolality and vasoconstriction in the body, and in the brain, it regulates social behavior, aggression, and anxiety. However, the circuit mechanisms that link AVP to social behavior, homeostatic function, and disease are not well understood.

Using i-PARIHS to assess implementation of the Surgical Safety Checklist: an international qualitative study.

Background: Strategies selected to implement the WHO's Surgical Safety Checklist (SSC) are key factors in its ability to improve patient safety. Underutilization of implementation frameworks for informing implementation processes hinders our understanding of the checklists' varying effectiveness in different contexts. This study explored the extent to which SSC implementation practices could be assessed through the i-PARIHS framework and examined how it could support development of targeted recommendations to improve SSC implementation in high-income settings.

Multiple pathways mediate chloroplast singlet oxygen stress signaling.

Chloroplast singlet oxygen initiates multiple pathways to control chloroplast degradation, cell death, and nuclear gene expression. Chloroplasts can respond to stress and changes in the environment by producing reactive oxygen species (ROS). Aside from being cytotoxic, ROS also have signaling capabilities.

Targeted for destruction: degradation of singlet oxygen-damaged chloroplasts.

Photosynthesis is an essential process that plants must regulate to survive in dynamic environments. Thus, chloroplasts (the sites of photosynthesis in plant and algae cells) use multiple signaling mechanisms to report their health to the cell. Such signals are poorly understood but often involve reactive oxygen species (ROS) produced from the photosynthetic light reactions.

Control of chloroplast degradation and cell death in response to stress.

Chloroplasts are the sites of photosynthesis in plants and algae and, by extension, are essential for most life on Earth. Their maintenance is costly and complex due to the inherent photo-oxidative damage incurred by photosynthetic chemistry. Chloroplast degradation and cell death are mechanisms by which plants acclimate to such stress and serve a dual purpose: protecting cells and organs by removing reactive oxygen species-producing chloroplasts and redistributing nutrients to other tissues.

Singlet Oxygen Leads to Structural Changes to Chloroplasts during their Degradation in the Arabidopsis thaliana plastid ferrochelatase two Mutant.

During stress, chloroplasts produce large amounts of reactive oxygen species (ROS). Chloroplasts also contain many nutrients, including 80% of a leaf's nitrogen supply. Therefore, to protect cells from photo-oxidative damage and to redistribute nutrients to sink tissues, chloroplasts are prime targets for degradation.

The core autophagy machinery is not required for chloroplast singlet oxygen-mediated cell death in the Arabidopsis thaliana plastid ferrochelatase two mutant.

Background: Chloroplasts respond to stress and changes in the environment by producing reactive oxygen species (ROS) that have specific signaling abilities. The ROS singlet oxygen (O) is unique in that it can signal to initiate cellular degradation including the selective degradation of damaged chloroplasts. This chloroplast quality control pathway can be monitored in the Arabidopsis thaliana mutant plastid ferrochelatase two (fc2) that conditionally accumulates chloroplast O under diurnal light cycling conditions leading to rapid chloroplast degradation and eventual cell death.

Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two.

Reactive oxygen species (ROS) produced in chloroplasts cause oxidative damage, but also signal to initiate chloroplast quality control pathways, cell death, and gene expression. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant produces the ROS singlet oxygen in chloroplasts that activates such signaling pathways, but the mechanisms are largely unknown. Here we characterize one fc2 suppressor mutation and map it to CYTIDINE TRIPHOSPHATE SYNTHASE TWO (CTPS2), which encodes one of five enzymes in Arabidopsis necessary for de novo cytoplasmic CTP (and dCTP) synthesis.

Intermittent claudication treatment patterns in the commercially insured non-Medicare population.

Objective: Despite published guidelines and data for Medicare patients, it is uncertain how younger patients with intermittent claudication (IC) are treated. Additionally, the degree to which treatment patterns have changed over time with the expansion of endovascular interventions and outpatient centers is unclear. Our goal was to characterize IC treatment patterns in the commercially insured non-Medicare population.

Closing the Gap Between Mammalian and Invertebrate Peripheral Nerve Injury: Protocol for a Novel Nerve Repair.

Background: Outcomes after peripheral nerve injuries are poor despite current nerve repair techniques. Currently, there is no conclusive evidence that mammalian axons are capable of spontaneous fusion after transection. Notably, certain invertebrate species are able to auto-fuse after transection.

Roles for the chloroplast-localized pentatricopeptide repeat protein 30 and the 'mitochondrial' transcription termination factor 9 in chloroplast quality control.

Chloroplasts constantly experience photo-oxidative stress while performing photosynthesis. This is particularly true under abiotic stresses that lead to the accumulation of reactive oxygen species (ROS) which oxidize DNA, proteins and lipids. Reactive oxygen species can also act as signals to induce acclimation through chloroplast degradation, cell death and nuclear gene expression.

Chloroplast Autophagy and Ubiquitination Combine to Manage Oxidative Damage and Starvation Responses.

Autophagy and the ubiquitin-proteasome system are the major degradation processes for intracellular components in eukaryotes. Although ubiquitination acts as a signal inducing organelle-targeting autophagy, the interaction between ubiquitination and autophagy in chloroplast turnover has not been addressed. In this study, we found that two chloroplast-associated E3 enzymes, SUPPRESSOR OF PPI1 LOCUS1 and PLANT U-BOX4 (PUB4), are not necessary for the induction of either piecemeal autophagy of chloroplast stroma or chlorophagy of whole damaged chloroplasts in Arabidopsis ().

Development and validation of machine learning models to predict gastrointestinal leak and venous thromboembolism after weight loss surgery: an analysis of the MBSAQIP database.

Background: Postoperative gastrointestinal leak and venous thromboembolism (VTE) are devastating complications of bariatric surgery. The performance of currently available predictive models for these complications remains wanting, while machine learning has shown promise to improve on traditional modeling approaches. The purpose of this study was to compare the ability of two machine learning strategies, artificial neural networks (ANNs), and gradient boosting machines (XGBs) to conventional models using logistic regression (LR) in predicting leak and VTE after bariatric surgery.

Chloroplast stress signals: regulation of cellular degradation and chloroplast turnover.

For 40 years, it has been known that chloroplasts signal to the nucleus and the cell to coordinate gene expression, maximize photosynthesis, and avoid stress. However, the signaling mechanisms have been challenging to uncover due to the complexity of these signals and the stresses that induce them. New research has shown that many signals are induced by singlet oxygen, a natural by-product of inefficient photosynthesis.

Readiness Of Medical Providers In The Military Health System: Overview Of Operational And Policy Considerations.

US military forces have diverse missions, including combat, response to natural disasters, humanitarian assistance, training, and diplomacy. The military's medical forces, composed of clinical providers from the Army, Navy, and Air Force, support these operations-often on a moment's notice. The Military Health System (MHS) must ensure that medical providers are always trained and equipped to deliver care when deployed on missions in often austere environments.

Author Correction: Task-dependent representations of stimulus and choice in mouse parietal cortex.

In the original version of this Article, the Acknowledgements section was inadvertently omitted. This has now been corrected in both the PDF and HTML versions of the Article.