Epigenome plasticity in plants.

Plant intra-individual and inter-individual variation can be determined by the epigenome, a set of covalent modifications of DNA and chromatin that can alter genome structure and activity without changes to the genome sequence. The epigenome of plant cells is plastic, that is, it can change in response to internal or external cues, such as during development or due to environmental changes, to create a memory of such events. Ongoing advances in technologies to read and write epigenomic patterns with increasing resolution, scale and precision are enabling the extent of plant epigenome variation to be more extensively characterized and functionally interrogated. In this Review, we discuss epigenome dynamics and variation within plants during development and in response to environmental changes, including stress, as well as between plants. We review known or potential functions of such plasticity and emphasize the importance of investigating the causality of epigenomic changes. Finally, we discuss emerging technologies that may underpin future research into plant epigenome plasticity.

The TOPLESS corepressor regulates developmental switches in the bryophyte Physcomitrium patens that were critical for plant terrestrialisation.

The plant-specific TOPLESS (TPL) family of transcriptional corepressors is integral to multiple angiosperm developmental processes. Despite this, we know little about TPL function in other plants. To address this gap, we investigated the roles TPL plays in the bryophyte Physcomitrium patens, which diverged from angiosperms approximately 0.5 billion years ago. Although complete loss of PpTPL function is lethal, transgenic lines with reduced PpTPL activity revealed that PpTPLs are essential for two fundamental developmental switches in this plant: the transitions from basal photosynthetic filaments (chloronemata) to specialised foraging filaments (caulonemata) and from two-dimensional (2D) to three-dimensional (3D) growth. Using a transcriptomics approach, we integrated PpTPL into the regulatory network governing 3D growth and we propose that PpTPLs represent another important class of regulators that are essential for the 2D-to-3D developmental switch. Transcriptomics also revealed a previously unknown role for PpTPL in the regulation of flavonoids. Intriguingly, 3D growth and the formation of caulonemata were crucial innovations that facilitated the colonisation of land by plants, a major transformative event in the history of life on Earth. We conclude that TPL, which existed before the land plants, was co-opted into new developmental pathways, enabling phytoterrestrialisation and the evolution of land plants.

Research priorities in regional anaesthesia: an international Delphi study.

BACKGROUND: Regional anaesthesia use is growing worldwide, and there is an increasing emphasis on research in regional anaesthesia to improve patient outcomes. However, priorities for future study remain unclear. We therefore conducted an international research prioritisation exercise, setting the agenda for future investigators and funding bodies. METHODS: We invited members of specialist regional anaesthesia societies from six continents to propose research questions that they felt were unanswered. These were consolidated into representative indicative questions, and a literature review was undertaken to determine if any indicative questions were already answered by published work. Unanswered indicative questions entered a three-round modified Delphi process, whereby 29 experts in regional anaesthesia (representing all participating specialist societies) rated each indicative question for inclusion on a final high priority shortlist. If ≥75% of participants rated an indicative question as 'definitely' include in any round, it was accepted. Indicative questions rated as 'definitely' or 'probably' by <50% of participants in any round were excluded. Retained indicative questions were further ranked based on the rating score in the final Delphi round. The final research priorities were ratified by the Delphi expert group. RESULTS: There were 1318 responses from 516 people in the initial survey, from which 71 indicative questions were formed, of which 68 entered the modified Delphi process. Eleven 'highest priority' research questions were short listed, covering themes of pain management; training and assessment; clinical practice and efficacy; technology and equipment. CONCLUSIONS: We prioritised unanswered research questions in regional anaesthesia. These will inform a coordinated global research strategy for regional anaesthesia and direct investigators to address high-priority areas.

Does Host Plant Drive Variation in Microbial Gut Communities in a Recently Shifted Pest?

Biotic interactions can modulate the responses of organisms to environmental stresses, including diet changes. Gut microbes have substantial effects on diverse ecological and evolutionary traits of their hosts, and microbial communities can be highly dynamic within and between individuals in space and time. Modulations of the gut microbiome composition and their potential role in the success of a species to maintain itself in a new environment have been poorly studied to date. Here we examine this question in a large wood-boring beetle Cacosceles newmannii (Cerambycidae), that was recently found thriving on a newly colonized host plant. Using 16S metabarcoding, we assessed the gut bacterial community composition of larvae collected in an infested field and in "common garden" conditions, fed under laboratory-controlled conditions on four either suspected or known hosts (sugarcane, tea tree, wattle, and eucalyptus). We analysed microbiome variation (i.e. diversity and differentiation), measured fitness-related larval growth, and studied host plant lignin and cellulose contents, since their degradation is especially challenging for wood-boring insects. We show that sugarcane seems to be a much more favourable host for larval growth. Bacterial diversity level was the highest in field-collected larvae, whereas lab-reared larvae fed on sugarcane showed a relatively low level of diversity but very specific bacterial variants. Bacterial communities were mainly dominated by Proteobacteria, but were significantly different between sugarcane-fed lab-reared larvae and any other hosts or field-collected larvae. We identified changes in the gut microbiome associated with different hosts over a short time frame, which support the hypothesis of a role of the microbiome in host switches.

Variability between human experts and artificial intelligence in identification of anatomical structures by ultrasound in regional anaesthesia: a framework for evaluation of assistive artificial intelligence.

BACKGROUND: ScanNavTMAnatomy Peripheral Nerve Block (ScanNav™) is an artificial intelligence (AI)-based device that produces a colour overlay on real-time B-mode ultrasound to highlight key anatomical structures for regional anaesthesia. This study compares consistency of identification of sono-anatomical structures between expert ultrasonographers and ScanNav™. METHODS: Nineteen experts in ultrasound-guided regional anaesthesia (UGRA) annotated 100 structures in 30 ultrasound videos across six anatomical regions. These annotations were compared with each other to produce a quantitative assessment of the level of agreement amongst human experts. The AI colour overlay was then compared with all expert annotations. Differences in human-human and human-AI agreement are presented for each structure class (artery, muscle, nerve, fascia/serosal plane) and structure. Clinical context is provided through subjective assessment data from UGRA experts. RESULTS: For human-human and human-AI annotations, agreement was highest for arteries (mean Dice score 0.88/0.86), then muscles (0.80/0.77), and lowest for nerves (0.48/0.41). Wide discrepancy exists in consistency for different structures, both with human-human and human-AI comparisons; highest for sartorius muscle (0.91/0.92) and lowest for the radial nerve (0.21/0.27). CONCLUSIONS: Human experts and the AI system both showed the same pattern of agreement in sono-anatomical structure identification. The clinical significance of the differences presented must be explored; however the perception that human expert opinion is uniform must be challenged. Elements of this assessment framework could be used for other devices to allow consistent evaluations that inform clinical training and practice. Anaesthetists should be actively engaged in the development and adoption of new AI technology.

Conformational trapping of an ABC transporter in polymer lipid nanoparticles.

ATP-binding cassette (ABC) proteins play important roles in cells as importers and exporters but as membrane proteins they are subject to well-known challenges of isolating pure and stable samples for study. One solution to this problem is to use styrene-maleic acid lipid particles (SMALPs). Styrene-maleic acid (SMA) can be added directly to membranes, forming stable nanoparticles incorporating membrane proteins and lipids. Here we use Sav1866, a well-characterised bacterial protein, as a proxy for ABC proteins in general. We show that stable and monodispersed Sav1866 can be purified at high yield using SMA. This protein can be used for biophysical characterisations showing that its overall structure is consistent with existing evidence. However, like other ABC proteins in SMALPs it does not hydrolyse ATP. The lack of ATPase activity in ABC-SMALPs may result from conformational trapping of the proteins in SMALPs. Undertaken in a controlled manner, conformational trapping is a useful tool to stabilise protein samples into a single conformation for structural studies. Due to their inability to hydrolyse ATP, the conformation of Sav1866-SMALPs cannot be altered using ATP and vanadate after purification. To achieve controlled trapping of Sav1866-SMALPs we show that Sav1866 in crude membranes can be incubated with ATP, magnesium and sodium orthovanadate. Subsequent solubilisation and purification with SMA produces a sample of Sav1866-SMALPs with enhanced stability, and in a single conformational state. This method may be generally applicable to vanadate-sensitive ABC proteins and overcomes a limitation of the SMALP system for the study of this protein family.

Opioid use disorder treatment and the role of New Jersey Medicaid policy changes: perspectives of office-based buprenorphine providers.

Background: In the US, seventy percent of drug-related deaths are attributed to opioids. In response to the ongoing opioid crisis, New Jersey's (NJ) Medicaid program implemented the MATrx model to increase treatment access for Medicaid participants with opioid use disorder (OUD). The model's goals include increasing the number of office-based treatment providers, enhancing Medicaid reimbursement for certain treatment services, and elimination of prior authorizations for OUD medications.Objectives: To explore office-based addiction treatment providers' experiences delivering care in the context of statewide policy changes and their perspectives on treatment access changes and remaining barriers.Methods: This qualitative study used purposive sampling to recruit office-based New Jersey medications for opioid use disorder (MOUD) providers . Twenty-two providers (11 females, 11 males) discussed treatment experiences since the policy changes in 2019, including evaluations of the current state of OUD care in New Jersey and perceived outcomes of the MATrx model policy changes.Results: Providers reported the MOUD climate in NJ improved as Medicaid implemented policies intended to reduce barriers to care and increase treatment access. Elimination of prior authorizations was noted as important, as it reduced provider burden and allowed greater focus on care delivery. However, barriers remained, including stigma, pharmacy supply issues, and difficulty obtaining injectable or non-generic medication formulations.Conclusion: NJ policies may have improved access to care for Medicaid beneficiaries by reducing barriers to care and supporting providers in prescribing MOUD. Yet, stigma and lack of psychosocial supports still need to be addressed to further improve access and care quality.

Evolutionary analysis and quality assessment of ζ-carbonic anhydrase sequences from environmental microbiome.

Carbonic anhydrase (CA) is one of the most vital enzymes in living cells. This study has been performed due to the significance of this metalloenzyme for life and the novelty of some CA families like ζ-CA to evaluate evolutionary processes and quality check their sequences. In this study, bioinformatics methods revealed the presence of ζ-CA in some eukaryotic and prokaryotic microorganisms. Notably, it has not been previously reported in prokaryotes. The coexistence of ß- and ζ-CAs in some microorganisms is also a novel finding as well. Also, our analysis identified several CA proteins with 6-14 amino acid intervals between histidine and cysteine in the second highly conserved motif, which can be classified as the novel ζ-CA subfamily members that emerged under the Zn deficiency of aquatic ecosystems and selection pressure in these environments. There is also a possibility that the achieved results are rooted in the contamination of samples from the environmental microbiome genome with genomes of diatom species and the occurrence of errors was observed in the DNA sequencing outcomes. Combining of all results from evolutionary analysis to quality control of ζ-CA DNA sequences is the incentive motivation to explore more the hidden aspects of ζ-CAs.

Five-year outcomes of transcatheter mitral valve implantation and redo surgery for mitral prosthesis degeneration.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) has emerged as a feasible alternative to redo surgical mitral valve replacement (SMVR) in patients with degenerated mitral prostheses, with limited comparative data. METHODS: We compared mid-term outcomes in patients with degenerated mitral valve prostheses treated with TMVR or redo SMVR. The primary endpoint was survival at 5 years of follow-up. RESULTS: From 2014 to 2020, 215 patients presented with degenerated mitral valve prostheses. Of whom 86 (40%) were treated with TMVR (75[87%] valve-in-valve and 11[13%] valve-in-ring), while 129 patients (60%) underwent SMVR. The TMVR cohort was older (p < 0.0001), more symptomatic (p = 0.0003) and had more chronic lung disease (p = 0.02), worse renal function (p = 0.02) and higher right ventricular systolic pressures (p < 0.0001). Thirty-day mortality was lower with TMVR versus SMVR (2.4% vs. 10.2%, OR4.69 [95% CI 1.25-30.5], p = 0.04) with probability of mortality at 1, 2, and 5 years being 14.7% versus 17.5%, 24.5% versus 20.7%, and 49.9% versus 34.0%, respectively. Mode of prosthesis degeneration, baseline hemodynamics, and valve selection did not appreciably impact outcomes. CONCLUSIONS: TMVR for degenerated mitral prostheses is associated with better early survival compared to SMVR despite a greater burden of comorbidities. In contrast, 5 year survival rates appear more favorable with SMVR, which may reflect the lower baseline risk of this population. Clinical, hemodynamic, and echocardiographic follow-up support the mid-term durability of TMVR for degenerated mitral prostheses. Further dedicated studies, however, are required to optimize outcomes in this challenging patient cohort and to navigate the choice of approach for each individual patient.

Atrial mitral regurgitation: Characteristics and outcomes of transcatheter mitral valve edge-to-edge repair.

BACKGROUND: Mitral transcatheter edge-to-edge repair (MTEER) is an established therapeutic approach for mitral regurgitation (MR). Functional mitral regurgitation originating from atrial myopathy (A-FMR) has been described. OBJECTIVES: We sought to assess the clinical, echocardiographic and hemodynamic considerations in A-FMR patients undergoing MTEER. METHODS: From 2014 to 2020, patients undergoing MTEER for degenerative MR (DMR), functional MR (FMR), and mixed MR were assessed. A-FMR was defined by the presence of MR > moderate in severity; left ventricular (LV) ejection fraction (LVEF) ≥ 50%; and severe left atrial (LA) enlargement in the absence of LV dysfunction, leaflet pathology, or LV tethering. The diagnosis of A-FMR (vs. ventricular-FMR [V-FMR]) was confirmed by three independent echocardiographers. Baseline characteristics, procedural outcomes as well as clinical and echocardiographic follow-up are reported. Device success was defined as final MR grade ≤ moderate; MR reduction ≥1 grade; and final transmitral gradient <5 mmHg. RESULTS: 306 patients underwent MTEER, including DMR (62%), FMR (19%), and mixed MR (19%). FMR cases included 37 (63.8%) V-FMR and 21 (36.2%) A-FMR. Tricuspid regurgitation (≥ moderate) was higher in A-FMR (80.1%) compared to V-FMR (54%) and DMR (42%). Device success did not significantly differ between A-FMR and V-FMR (57% vs. 73%, p = 0.34) or DMR (57% vs. 64%, p = 1.0). The A-FMR cohort was less likely to achieve ≥3 grades of MR reduction compared to V-FMR (19% vs. 54%, p = 0.01) and DMR (19% vs. 49.7%, p = 0.01). Patients with V-FMR and DMR demonstrated significant reductions in mean left atrial pressure (LAP) and peak LA V-wave, though A-FMR did not (LAP -0.24 ± 4.9, p = 0.83; peak V-wave -1.76 ± 9.1, p = 0.39). In follow-up, echocardiographic and clinical outcomes were similar. CONCLUSIONS: In patients undergoing MTEER, A-FMR represents one-third of FMR cases. A-FMR demonstrates similar procedural success but blunted acute hemodynamic responses compared with DMR and V-FMR following MTEER. Dedicated studies specifically considering A-FMR are needed to discern the optimal therapeutic approaches.

Artificial Intelligence: Innovation to Assist in the Identification of Sono-anatomy for Ultrasound-Guided Regional Anaesthesia.

Ultrasound-guided regional anaesthesia (UGRA) involves the targeted deposition of local anaesthesia to inhibit the function of peripheral nerves. Ultrasound allows the visualisation of nerves and the surrounding structures, to guide needle insertion to a perineural or fascial plane end point for injection. However, it is challenging to develop the necessary skills to acquire and interpret optimal ultrasound images. Sound anatomical knowledge is required and human image analysis is fallible, limited by heuristic behaviours and fatigue, while its subjectivity leads to varied interpretation even amongst experts. Therefore, to maximise the potential benefit of ultrasound guidance, innovation in sono-anatomical identification is required.Artificial intelligence (AI) is rapidly infiltrating many aspects of everyday life. Advances related to medicine have been slower, in part because of the regulatory approval process needing to thoroughly evaluate the risk-benefit ratio of new devices. One area of AI to show significant promise is computer vision (a branch of AI dealing with how computers interpret the visual world), which is particularly relevant to medical image interpretation. AI includes the subfields of machine learning and deep learning, techniques used to interpret or label images. Deep learning systems may hold potential to support ultrasound image interpretation in UGRA but must be trained and validated on data prior to clinical use.Review of the current UGRA literature compares the success and generalisability of deep learning and non-deep learning approaches to image segmentation and explains how computers are able to track structures such as nerves through image frames. We conclude this review with a case study from industry (ScanNav Anatomy Peripheral Nerve Block; Intelligent Ultrasound Limited). This includes a more detailed discussion of the AI approach involved in this system and reviews current evidence of the system performance.The authors discuss how this technology may be best used to assist anaesthetists and what effects this may have on the future of learning and practice of UGRA. Finally, we discuss possible avenues for AI within UGRA and the associated implications.

Imagery rescripting and negative self-imagery in social anxiety disorder: a systematic literature review.

BACKGROUND: Imagery rescripting (IR) is an effective intervention for social anxiety disorder (SAD) that targets memories of distressing formative events linked to negative self-imagery (NSI). IR is thought to update unhelpful schema by addressing the needs of the younger self within the memory. An accumulating body of evidence indicates that by modifying NSI, IR can significantly affect distressing imagery, memory appraisal, and beliefs about the self. AIMS: This systematic review aims to critically evaluate and synthesise literature investigating the existing research on the effects IR has on NSI in SAD. METHOD: A systematic electronic search of Academic Search Complete, ProQuest, Medline, Scopus and PubMed was performed in February 2021 using pre-defined criteria. Ten studies met the inclusion criteria and were selected for review. RESULTS: Analysis of the reviewed articles' findings identified three main themes: Changes to negative self-images, Memories linked to images and Encapsulated beliefs. IR was associated with significant decreases in image distress, image vividness, memory vividness, memory distress, and encapsulated beliefs. Although reductions were found with image frequency, they were non-significant. Interpretation of results is limited by the small number of studies. CONCLUSIONS: IR appears to effectively alter images, memories and beliefs in SAD in as little as a single session. The findings indicate that IR could be utilised as a cost-effective intervention for SAD. However, additional studies and longer-term follow-ups are needed.

Mapping the interaction between eukaryotic initiation factor 4A (eIF4A) and the inhibitor hippuristanol using carbene footprinting and mass spectrometry.

Protein-ligand interactions are central to protein activity and cell functionality. Improved knowledge of these relationships greatly benefits our understanding of key biological processes and aids in rational drug design towards the treatment of clinically relevant diseases. Carbene footprinting is a recently developed mass spectrometry-based chemical labelling technique that provides valuable information relating to protein-ligand interactions, such as the mapping of binding sites and associated conformational change. Here, we show the application of carbene footprinting to the interaction between eIF4A helicase and a natural product inhibitor, hippuristanol, found in the coral Isis hippuris. Upon addition of hippuristanol we identified reduced carbene labelling (masking) in regions of eIF4A previously implicated in ligand binding. Additionally, we detected hippuristanol-associated increased carbene labelling (unmasking) around the flexible hinge region of eIF4A, indicating ligand-induced conformational change. This work represents further development of the carbene footprinting technique and demonstrates its potential in characterising medicinally relevant protein-ligand interactions.

Cost-effectiveness of managing low-risk pulmonary embolism patients without hospitalization. The low-risk pulmonary embolism prospective management study.

OBJECTIVE: Evaluate the cost-effectiveness and difference in length-of-stay when patients in the ED diagnosed with low-risk pulmonary embolism (PE) are managed with early discharge or observation. METHODS: Single cohort prospective management study from January 2013 to October 2016 of patients with PE diagnosed in the ED and evaluated for a primary composite endpoint of mortality, recurrent venous thromboembolism, and/or major bleeding event at 90 days. Low-risk patients had a PE Severity Index score < 86, no evidence of proximal deep vein thrombosis on venous compression ultrasonography of both lower extremities, and no evidence of right heart strain on echocardiography. Patients were managed either in the ED or in the hospital on observation status. Primary outcomes were total length of stay, total encounter costs, and 30-day costs. RESULTS: 213 patients were enrolled. 13 were excluded per the study protocol. Of the remaining 200, 122 were managed with emergency department observation (EDO) and 78 with hospital observation (HO). One patient managed with EDO met the composite outcome due to a major bleeding event on day 61. The mean length of stay for EDO was 793.4 min (SD -169.7, 95% CI:762-823) and for HO was 1170 (SD -211.4, 95% CI:1122-1218) with a difference of 376.8 (95% CI: 430-323, p < 0.0001). Total encounter mean costs for EDO were $1982.95 and $2759.59 for HO, with a difference of $776.64 (95% CI: 972-480, p > 0.0001). 30-day total mean costs for EDO were $2864.14 and $3441.52 for HO, with a difference of $577.38 (95% CI: -1372-217, p = 0.15). CONCLUSIONS: Patients with low-risk PE managed with ED-based observation have a shorter length of stay and lower total encounter costs than patients managed with Hospital-based observation.

Risk score-guided multidisciplinary team-based Care for Heart Failure Inpatients is associated with lower 30-day readmission and lower 30-day mortality.

OBJECTIVE: Using augmented intelligence clinical decision tools and a risk score-guided multidisciplinary team-based care process (MTCP), this study evaluated the MTCP for heart failure (HF) patients' 30-day readmission and 30-day mortality across 20 Intermountain Healthcare hospitals. BACKGROUND: HF inpatient care and 30-day post-discharge management require quality improvement to impact patient health, optimize utilization, and avoid readmissions. METHODS: HF inpatients (N = 6182) were studied from January 2013 to November 2016. In February 2014, patients began receiving care via the MTCP based on a phased implementation in which the 8 largest Intermountain hospitals (accounting for 89.8% of HF inpatients) were crossed over sequentially in a stepped manner from control to MTCP over 2.5 years. After implementation, patient risk scores were calculated within 24 hours of admission and delivered electronically to clinicians. High-risk patients received MTCP care (n = 1221), while lower-risk patients received standard HF care (n = 1220). Controls had their readmission and mortality scores calculated retrospectively (high risk: n = 1791; lower risk: n = 1950). RESULTS: High-risk MTCP recipients had 21% lower 30-day readmission compared to high-risk controls (adjusted P = .013, HR = 0.79, CI = 0.66, 0.95) and 52% lower 30-day mortality (adjusted P < .001, HR = 0.48, CI = 0.33, 0.69). Lower-risk patients did not experience increased readmission (adjusted HR = 0.88, P = .19) or mortality (adjusted HR = 0.88, P = .61). Some utilization was higher, such as prescription of home health, for MTCP recipients, with no changes in length of stay or overall costs. CONCLUSIONS: A risk score-guided MTCP was associated with lower 30-day readmission and 30-day mortality in high-risk HF inpatients. Further evaluation of this clinical management approach is required.

Ventricular asystole in the presence of a biventricular device.

In pacemaker-dependent patients with a newly implanted cardiac device, acute lead dislodgement constitutes one of the most common causes of loss of capture and ventricular asystole. In a biventricular system, it would be expected that such a potentially catastrophic event would be prevented with back-up right ventricular pacing unless both leads dislodge.

Hemodynamics rounds: Hemodynamics of mitral valve interventions.

Mitral valvulopathy presents as regurgitation, stenosis, or mixed disease and can occur in both native and prosthetic valves. Such disease develops in conjunction with pathophysiologic changes in the left atrium (LA) and drives changes in LA compliance, pressure, and thus clinical syndromes. With advances in the understanding and treatment of structural heart disease and in the setting of higher-risk patient populations, less-invasive transcatheter approaches have become increasingly commonplace in the treatment of mitral valve disease. Over time, transcatheter mitral valve interventions have evolved to include paravalvular leak closure, mitral valve repair, and mitral valve replacement. Parallel to this evolution, advances in invasive intracardiac pressure monitoring, particularly at the level of the LA, have also occurred. These advances emphasize the unique interplay between mitral valve disease and LA function; account for limitations of noninvasive assessment; and guide beneficial outcomes in each area of transcatheter mitral valve intervention. As a result, continuous transseptal LA pressure monitoring has developed into an indispensable instrument in successful percutaneous mitral valve intervention, complementing traditional noninvasive assessment.

The loss of SMG1 causes defects in quality control pathways in Physcomitrella patens.

Nonsense-mediated mRNA decay (NMD) is important for RNA quality control and gene regulation in eukaryotes. NMD targets aberrant transcripts for decay and also directly influences the abundance of non-aberrant transcripts. In animals, the SMG1 kinase plays an essential role in NMD by phosphorylating the core NMD factor UPF1. Despite SMG1 being ubiquitous throughout the plant kingdom, little is known about its function, probably because SMG1 is atypically absent from the genome of the model plant, Arabidopsis thaliana. By combining our previously established SMG1 knockout in moss with transcriptome-wide analysis, we reveal the range of processes involving SMG1 in plants. Machine learning assisted analysis suggests that 32% of multi-isoform genes produce NMD-targeted transcripts and that splice junctions downstream of a stop codon act as the major determinant of NMD targeting. Furthermore, we suggest that SMG1 is involved in other quality control pathways, affecting DNA repair and the unfolded protein response, in addition to its role in mRNA quality control. Consistent with this, smg1 plants have increased susceptibility to DNA damage, but increased tolerance to unfolded protein inducing agents. The potential involvement of SMG1 in RNA, DNA and protein quality control has major implications for the study of these processes in plants.

Hemodynamic and clinical response to transseptal mitral valve-in-valve and valve-in-ring.

OBJECTIVE: To understand the clinical and hemodynamic response of patients with stenotic versus regurgitant prosthetic mitral valve degeneration to transseptal transcatheter mitral valve-in-ring/-valve replacement (TMVR). BACKGROUND: Patients with prosthetic mitral valve repair/replacement failure frequently present high-risk surgical challenges. TMVR has been employed as an alternative to surgery. METHODS: Forty-four patients with stenotic/regurgitant degeneration of prior prosthetic mitral annuloplasty and replacement (38) underwent mitral TMVR. Clinical, echocardiographic, and invasive hemodynamic monitoring was conducted at baseline and follow-up. RESULTS: Relative to patients with regurgitant degeneration (28), patients with stenotic degeneration had baseline higher mitral valve gradients (12 ± 4 vs. 7 ± 3 mmHg, p < 0.01) and smaller areas (1.0 ± 0.4 vs. 1.5 ± 0.4 cm2 , p = 0.01). TMVR yielded significant reduction in left atrial v-wave pressures in stenotic and regurgitant cohorts (-7 ± 11, p = 0.03, and -11 ± 12 mmHg, p < 0.01, respectively) and significant, sustained symptomatic improvement. Intracardiac pressures overall, including left ventricular end diastolic pressures, remained elevated. CONCLUSION: Despite baseline differences in valvular disease, TMVR leads to significant hemodynamic and clinical improvement in both stenotic and regurgitant prosthetic mitral valve disease. In both cohorts, TMVR reduced intracardiac pressures to similar postprocedural levels, but pressures remained supranormal. This outcome suggests a multifactorial process defines the pathophysiology of patients undergoing TMVR, including contributions from prosthetic degeneration, changes in left atrial compliance, and diastolic dysfunction, and highlights the need to consider such factors in patient evaluation and treatment.

Cell division and turgor mediate enhanced plant growth in Arabidopsis plants treated with the bacterial signalling molecule lumichrome.

MAIN CONCLUSION: Transcriptomic analysis indicates that the bacterial signalling molecule lumichrome enhances plant growth through a combination of enhanced cell division and cell enlargement, and possibly enhances photosynthesis. Lumichrome (7,8 dimethylalloxazine), a novel multitrophic signal molecule produced by Sinorhizobium meliloti bacteria, has previously been shown to elicit growth promotion in different plant species (Phillips et al. in Proc Natl Acad Sci USA 96:12275-12280, https://doi.org/10.1073/pnas.96.22.12275 , 1999). However, the molecular mechanisms that underlie this plant growth promotion remain obscure. Global transcript profiling using RNA-seq suggests that lumichrome enhances growth by inducing genes impacting on turgor driven growth and mitotic cell cycle that ensures the integration of cell division and expansion of developing leaves. The abundance of XTH9 and XPA4 transcripts was attributed to improved mediation of cell-wall loosening to allow turgor-driven cell enlargement. Mitotic CYCD3.3, CYCA1.1, SP1L3, RSW7 and PDF1 transcripts were increased in lumichrome-treated Arabidopsis thaliana plants, suggesting enhanced growth was underpinned by increased cell differentiation and expansion with a consequential increase in biomass. Synergistic ethylene-auxin cross-talk was also observed through reciprocal over-expression of ACO1 and SAUR54, in which ethylene activates the auxin signalling pathway and regulates Arabidopsis growth by both stimulating auxin biosynthesis and modulating the auxin transport machinery to the leaves. Decreased transcription of jasmonate biosynthesis and responsive-related transcripts (LOX2; LOX3; LOX6; JAL34; JR1) might contribute towards suppression of the negative effects of methyl jasmonate (MeJa) such as chlorophyll loss and decreases in RuBisCO and photosynthesis. This work contributes towards a deeper understanding of how lumichrome enhances plant growth and development.