CTP regulates membrane-binding activity of the nucleoid occlusion protein Noc.

ATP- and GTP-dependent molecular switches are extensively used to control functions of proteins in a wide range of biological processes. However, CTP switches are rarely reported. Here, we report that a nucleoid occlusion protein Noc is a CTPase enzyme whose membrane-binding activity is directly regulated by a CTP switch. In Bacillus subtilis, Noc nucleates on 16 bp NBS sites before associating with neighboring non-specific DNA to form large membrane-associated nucleoprotein complexes to physically occlude assembly of the cell division machinery. By in vitro reconstitution, we show that (1) CTP is required for Noc to form the NBS-dependent nucleoprotein complex, and (2) CTP binding, but not hydrolysis, switches Noc to a membrane-active state. Overall, we suggest that CTP couples membrane-binding activity of Noc to nucleoprotein complex formation to ensure productive recruitment of DNA to the bacterial cell membrane for nucleoid occlusion activity.

Architecture of Microcin B17 Synthetase: An Octameric Protein Complex Converting a Ribosomally Synthesized Peptide into a DNA Gyrase Poison.

The introduction of azole heterocycles into a peptide backbone is the principal step in the biosynthesis of numerous compounds with therapeutic potential. One of them is microcin B17, a bacterial topoisomerase inhibitor whose activity depends on the conversion of selected serine and cysteine residues of the precursor peptide to oxazoles and thiazoles by the McbBCD synthetase complex. Crystal structures of McbBCD reveal an octameric B4C2D2 complex with two bound substrate peptides. Each McbB dimer clamps the N-terminal recognition sequence, while the C-terminal heterocycle of the modified peptide is trapped in the active site of McbC. The McbD and McbC active sites are distant from each other, which necessitates alternate shuttling of the peptide substrate between them, while remaining tethered to the McbB dimer. An atomic-level view of the azole synthetase is a starting point for deeper understanding and control of biosynthesis of a large group of ribosomally synthesized natural products.

The Dietary Supplement Chondroitin-4-Sulfate Exhibits Oncogene-Specific Pro-tumor Effects on BRAF V600E Melanoma Cells.

Dietary supplements such as vitamins and minerals are widely used in the hope of improving health but may have unidentified risks and side effects. In particular, a pathogenic link between dietary supplements and specific oncogenes remains unknown. Here we report that chondroitin-4-sulfate (CHSA), a natural glycosaminoglycan approved as a dietary supplement used for osteoarthritis, selectively promotes the tumor growth potential of BRAF V600E-expressing human melanoma cells in patient- and cell line-derived xenograft mice and confers resistance to BRAF inhibitors. Mechanistically, chondroitin sulfate glucuronyltransferase (CSGlcA-T) signals through its product CHSA to enhance casein kinase 2 (CK2)-PTEN binding and consequent phosphorylation and inhibition of PTEN, which requires CHSA chains and is essential to sustain AKT activation in BRAF V600E-expressing melanoma cells. However, this CHSA-dependent PTEN inhibition is dispensable in cancer cells expressing mutant NRAS or PI3KCA, which directly activate the PI3K-AKT pathway. These results suggest that dietary supplements may exhibit oncogene-dependent pro-tumor effects.

Bimodular architecture of bacterial effector SAP05 that drives ubiquitin-independent targeted protein degradation.

In eukaryotes, targeted protein degradation (TPD) typically depends on a series of interactions among ubiquitin ligases that transfer ubiquitin molecules to substrates leading to degradation by the 26S proteasome. We previously identified that the bacterial effector protein SAP05 mediates ubiquitin-independent TPD. SAP05 forms a ternary complex via interactions with the von Willebrand Factor Type A (vWA) domain of the proteasomal ubiquitin receptor Rpn10 and the zinc-finger (ZnF) domains of the SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) and GATA BINDING FACTOR (GATA) transcription factors (TFs). This leads to direct TPD of the TFs by the 26S proteasome. Here, we report the crystal structures of the SAP05-Rpn10vWA complex at 2.17 Å resolution and of the SAP05-SPL5ZnF complex at 2.20 Å resolution. Structural analyses revealed that SAP05 displays a remarkable bimodular architecture with two distinct nonoverlapping surfaces, a "loop surface" with three protruding loops that form electrostatic interactions with ZnF, and a "sheet surface" featuring two ß-sheets, loops, and α-helices that establish polar interactions with vWA. SAP05 binding to ZnF TFs involves single amino acids responsible for multiple contacts, while SAP05 binding to vWA is more stable due to the necessity of multiple mutations to break the interaction. In addition, positioning of the SAP05 complex on the 26S proteasome points to a mechanism of protein degradation. Collectively, our findings demonstrate how a small bacterial bimodular protein can bypass the canonical ubiquitin-proteasome proteolysis pathway, enabling ubiquitin-independent TPD in eukaryotic cells. This knowledge holds significant potential for the creation of TPD technologies.

A blast fungus zinc-finger fold effector binds to a hydrophobic pocket in host Exo70 proteins to modulate immune recognition in rice.

Exocytosis plays an important role in plant-microbe interactions, in both pathogenesis and symbiosis. Exo70 proteins are integral components of the exocyst, an octameric complex that mediates tethering of vesicles to membranes in eukaryotes. Although plant Exo70s are known to be targeted by pathogen effectors, the underpinning molecular mechanisms and the impact of this interaction on infection are poorly understood. Here, we show the molecular basis of the association between the effector AVR-Pii of the blast fungus Maganaporthe oryzae and rice Exo70 alleles OsExo70F2 and OsExo70F3, which is sensed by the immune receptor pair Pii via an integrated RIN4/NOI domain. The crystal structure of AVR-Pii in complex with OsExo70F2 reveals that the effector binds to a conserved hydrophobic pocket in Exo70, defining an effector/target binding interface. Structure-guided and random mutagenesis validates the importance of AVR-Pii residues at the Exo70 binding interface to sustain protein association and disease resistance in rice when challenged with fungal strains expressing effector mutants. Furthermore, the structure of AVR-Pii defines a zinc-finger effector fold (ZiF) distinct from the MAX (Magnaporthe Avrs and ToxB-like) fold previously described for a majority of characterized M. oryzae effectors. Our data suggest that blast fungus ZiF effectors bind a conserved Exo70 interface to manipulate plant exocytosis and that these effectors are also baited by plant immune receptors, pointing to new opportunities for engineering disease resistance.

The CTP-binding domain is disengaged from the DNA-binding domain in a cocrystal structure of Bacillus subtilis Noc-DNA complex.

In Bacillus subtilis, a ParB-like nucleoid occlusion protein (Noc) binds specifically to Noc-binding sites (NBSs) on the chromosome to help coordinate chromosome segregation and cell division. Noc does so by binding to CTP to form large membrane-associated nucleoprotein complexes to physically inhibit the assembly of the cell division machinery. The site-specific binding of Noc to NBS DNA is a prerequisite for CTP-binding and the subsequent formation of a membrane-active DNA-entrapped protein complex. Here, we solve the structure of a C-terminally truncated B. subtilis Noc bound to NBS DNA to reveal the conformation of Noc at this crucial step. Our structure reveals the disengagement between the N-terminal CTP-binding domain and the NBS-binding domain of each DNA-bound Noc subunit; this is driven, in part, by the swapping of helices 4 and 5 at the interface of the two domains. Site-specific crosslinking data suggest that this conformation of Noc-NBS exists in solution. Overall, our results lend support to the recent proposal that parS/NBS binding catalyzes CTP binding and DNA entrapment by preventing the reengagement of the CTP-binding domain and the DNA-binding domain from the same ParB/Noc subunit.

Exploring the interaction of N-(benzothiazol-2-yl)pyrrolamide DNA gyrase inhibitors with the GyrB ATP-binding site lipophilic floor: A medicinal chemistry and QTAIM study.

N-(Benzothiazole-2-yl)pyrrolamide DNA gyrase inhibitors with benzyl or phenethyl substituents attached to position 3 of the benzothiazole ring or to the carboxamide nitrogen atom were prepared and studied for their inhibition of Escherichia coli DNA gyrase by supercoiling assay. Compared to inhibitors bearing the substituents at position 4 of the benzothiazole ring, the inhibition was attenuated by moving the substituent to position 3 and further to the carboxamide nitrogen atom. A co-crystal structure of (Z)-3-benzyl-2-((4,5-dibromo-1H-pyrrole-2-carbonyl)imino)-2,3-dihydrobenzo[d]-thiazole-6-carboxylic acid (I) in complex with E. coli GyrB24 (ATPase subdomain) was solved, revealing the binding mode of this type of inhibitor to the ATP-binding pocket of the E. coli GyrB subunit. The key binding interactions were identified and their contribution to binding was rationalised by quantum theory of atoms in molecules (QTAIM) analysis. Our study shows that the benzyl or phenethyl substituents bound to the benzothiazole core interact with the lipophilic floor of the active site, which consists mainly of residues Gly101, Gly102, Lys103 and Ser108. Compounds with substituents at position 3 of the benzothiazole core were up to two orders of magnitude more effective than compounds with substituents at the carboxamide nitrogen. In addition, the 6-oxalylamino compounds were more potent inhibitors of E. coli DNA gyrase than the corresponding 6-acetamido analogues.

The pentapeptide-repeat protein, MfpA, interacts with mycobacterial DNA gyrase as a DNA T-segment mimic.

DNA gyrase, a type II topoisomerase, introduces negative supercoils into DNA using ATP hydrolysis. The highly effective gyrase-targeted drugs, fluoroquinolones (FQs), interrupt gyrase by stabilizing a DNA-cleavage complex, a transient intermediate in the supercoiling cycle, leading to double-stranded DNA breaks. MfpA, a pentapeptide-repeat protein in mycobacteria, protects gyrase from FQs, but its molecular mechanism remains unknown. Here, we show that Mycobacterium smegmatis MfpA (MsMfpA) inhibits negative supercoiling by M. smegmatis gyrase (Msgyrase) in the absence of FQs, while in their presence, MsMfpA decreases FQ-induced DNA cleavage, protecting the enzyme from these drugs. MsMfpA stimulates the ATPase activity of Msgyrase by directly interacting with the ATPase domain (MsGyrB47), which was confirmed through X-ray crystallography of the MsMfpA-MsGyrB47 complex, and mutational analysis, demonstrating that MsMfpA mimics a T (transported) DNA segment. These data reveal the molecular mechanism whereby MfpA modulates the activity of gyrase and may provide a general molecular basis for the action of other pentapeptide-repeat proteins.

Structural insights into the mechanism of adaptive ribosomal modification by Pseudomonas RimK.

Bacteria are equipped with a diverse set of regulatory tools that allow them to quickly adapt to their environment. The RimK system allows for Pseudomonas spp. to adapt through post-transcriptional regulation by altering the ribosomal subunit RpsF. RimK is found in a wide range of bacteria with a conserved amino acid sequence, however, the genetic context and the role of this protein is highly diverse. By solving and comparing the structures of RimK homologs from two related but functionally divergent systems, we uncovered key structural differences that likely contribute to the different activity levels of each of these homologs. Moreover, we were able to clearly resolve the active site of this protein for the first time, resolving binding of the glutamate substrate. This work advances our understanding of how subtle differences in protein sequence and structure can have profound effects on protein activity, which can in turn result in widespread mechanistic changes.

A novel mutant allele of AtCNGC15 reveals a dual function of nuclear calcium release in the root meristem.

Calcium release to the nucleoplasm of root meristem cells was demonstrated to modulate root development. The calcium channel encoded by cyclic nucleotide-gated channel (CNGC) 15 localizes at the nuclear envelope in young Arabidopsis seedlings. In contrast, at later stages of root growth, overexpression analysis showed that AtCNGC15 can relocalize to the plasma membrane to mediate primary nitrate-induced gene expression. This raises the question as to whether nuclear localized AtCNGC15 is required for root apical meristem development in young Arabidopsis seedlings, and whether nitrate signalling occurs independently of nuclear localized AtCNGC15 at this developmental stage. In this study, we characterize a novel mutant allele of AtCNGC15 and demonstrate that the mutation of a highly conserved aspartic acid in the C-linker domain is sufficient to impair the gating of AtCNCG15. We demonstrate that AtCNGC15 mediates the nuclear calcium release that modulates root apical meristem development and nitrate-induced LBD39 expression. We also show that, in the presence of nitrate, the relocalization of AtCNGC15 at the plasma membrane occurs specifically in the columella cells. Our results further suggest that the induction of LBD37, LBD38, and LBD39 in the presence of nitrate is modulated by different inputs of cytoplasmic or nuclear calcium release.

Quality of life outcomes in incidental and operated meningiomas (QUALMS): a cross-sectional cohort study.

INTRODUCTION: Few studies have evaluated meningioma patients' longer-term health-related quality of life (HRQoL) following diagnosis and treatment, particularly in those with incidental, actively monitored tumours. METHODS: A single-center, cross-sectional study was completed. Adult patients with surgically managed or actively monitored meningioma with more than five years of follow-up were included. The patient-reported outcome measures RAND SF-36, EORTC QLQ-C30 and QLQ-BN20 were used to evaluate HRQoL. HRQoL scores were compared to normative population data. Outcome determinants were evaluated using multivariate linear regression analysis. RESULTS: 243 patient responses were analyzed, and the mean time from diagnosis was 9.8 years (range 5.0-40.3 years). Clinically relevant, statistically significant HRQoL impairments were identified across several SF-36 and QLQ-C30 domains. Increasing education level (ß = 2.9, 95% CI 0.9 to 4.9), P = .004), employment (ß = 7.7, 95% CI 2.2 to 13.1, P = .006) and absence of postoperative complications (ß=-6.7, 95% CI -13.2 to (-)0.3, P = .041) were associated with a better QLQ-C30 summary score. Other tumour and treatment variables were not. CONCLUSION: This study highlights the longer-term disease burden of patients with meningioma nearly one decade after diagnosis or surgery. Patients with actively monitored meningioma have similar HRQoL to operated meningioma patients. Healthcare professionals should be mindful of HRQoL impairments and direct patients to sources of support as needed.

Metabolic Rewiring by Oncogenic BRAF V600E Links Ketogenesis Pathway to BRAF-MEK1 Signaling.

Many human cancers share similar metabolic alterations, including the Warburg effect. However, it remains unclear whether oncogene-specific metabolic alterations are required for tumor development. Here we demonstrate a "synthetic lethal" interaction between oncogenic BRAF V600E and a ketogenic enzyme 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL). HMGCL expression is upregulated in BRAF V600E-expressing human primary melanoma and hairy cell leukemia cells. Suppression of HMGCL specifically attenuates proliferation and tumor growth potential of human melanoma cells expressing BRAF V600E. Mechanistically, active BRAF upregulates HMGCL through an octamer transcription factor Oct-1, leading to increased intracellular levels of HMGCL product, acetoacetate, which selectively enhances binding of BRAF V600E but not BRAF wild-type to MEK1 in V600E-positive cancer cells to promote activation of MEK-ERK signaling. These findings reveal a mutation-specific mechanism by which oncogenic BRAF V600E "rewires" metabolic and cell signaling networks and signals through the Oct-1-HMGCL-acetoacetate axis to selectively promote BRAF V600E-dependent tumor development.

Structural basis of cycloaddition in biosynthesis of iboga and aspidosperma alkaloids.

Cycloaddition reactions generate chemical complexity in a single step. Here we report the crystal structures of three homologous plant-derived cyclases involved in the biosynthesis of iboga and aspidosperma alkaloids. These enzymes act on the same substrate, named angryline, to generate three distinct scaffolds. Mutational analysis reveals how these highly similar enzymes control regio- and stereo-selectivity.

Correlates of financial toxicity in adult cancer patients and their informal caregivers.

BACKGROUND: Financial toxicity is commonly reported by cancer patients, but few studies have assessed caregiver perceptions. We aimed to validate the modified Comprehensive Score for Financial Toxicity (COST) in cancer caregivers, identify factors associated with financial toxicity in both patients and caregivers, and assess the association of caregiver financial toxicity with patient and caregiver outcomes. METHODS: Using a convenience sampling method, 100 dyads of adult cancer patients and a primary caregiver visiting outpatient oncology clinics (Jan-Sep 2019) were recruited. We assessed the internal consistency and convergent and divergent validity of the modified COST. Multivariable analyses identified correlates of financial toxicity. Association of financial toxicity with care non-adherence, lifestyle-altering behaviors (e.g., home refinance/sale, retirement/saving account withdrawal), and quality of life (QOL) was investigated. RESULTS: Recruited patient vs. caregiver characteristics were as follows: mean age: 60.6 vs. 56.5; 34% vs. 46.4% female; 79% vs. 81.4% white. The caregiver COST measure demonstrated high internal consistency (Cronbach α = 0.91). In patients, older age (B, 0.3 [95% CI, 0.1-0.4]) and higher annual household income (B, 14.3 [95% CI, 9.3-19.4]) correlated with lower financial toxicity (P < 0.05). In caregivers, lower patient financial toxicity (B, 0.4 [95% CI, 0.2-0.6]) and cancer stages 1-3 (compared to stage 4) (B, 4.6 [95% CI, 0.4-8.8]) correlated with lower financial toxicity (P < 0.05). Increased caregiver financial toxicity correlated with higher care non-adherence in patients, increased lifestyle-altering behaviors, and lower QOL in patients and caregivers (P < 0.05). CONCLUSION: The COST measure can also be used to assess caregiver financial toxicity. Caregivers' financial toxicity was associated with negative outcomes for both dyad members.

Evaluating telehealth delivery of a compensatory memory rehabilitation programme following stroke: A single-case experimental design.

Rehabilitation of memory remains an unmet need for many stroke survivors. Telehealth methods may provide a solution, however evidence supporting the efficacy of remotely-delivered therapy is needed. A non-concurrent multiple baseline design was used with randomized onset of intervention across five individuals with chronic stroke-related memory complaints. A six-week compensatory memory skills programme was delivered individually via internet videoconferencing. Target behaviours of frequencies of self-reported lapses of everyday and prospective memory were measured weekly across baseline, intervention, and follow-up phases. A secondary outcome of functional goal attainment was measured once per phase, with participants setting two personal rehabilitation goals. Data were analysed visually and statistically. Improvements in memory functioning were statistically significant on at least one measure of target behaviour for four out of five participants at intervention or follow-up. Visual evidence of level change indicated at least modest improvements for all participants by follow-up. All participants attained at least one functional goal by follow-up. High rates of treatment adherence and participant satisfaction were observed. Technological issues were minimal and did not impact content delivery or engagement. These results provide preliminary support for the efficacy of a telehealth-delivered rehabilitation programme in improving memory function and achieving memory-related goals for stroke survivors.

Acceptability of telehealth in post-stroke memory rehabilitation: A qualitative analysis.

Despite evidence of the efficacy of telerehabilitation post-stroke, uptake has lagged behind the development of available technology, slowed by low confidence in user experience. We aimed to explore the issue of acceptability by characterizing the experience of telerehabilitation for service providers and consumers of a memory rehabilitation program. Semi-structured interviews were conducted with nine clinicians (Mage = 33.29; SD = 7.37; range 25-44) and 25 stroke survivors with memory difficulties (Mage = 54.12; SD = 10.99; range 36-82) following a 6-week compensatory memory skills program delivered via in-home videoconferencing. Thematic analysis identified a range of perspectives under three overarching themes: (1) Content and Delivery; (2) Relationship and Connection; and (3) The Role and Benefits of Telerehabilitation. Reports from both respondent groups were overwhelmingly positive about the telerehabilitation experience and identified the benefits of increasing service availability. Videoconferencing technology was usable and occasional reliability issues were not a barrier. Users identified a range of benefits and challenges regarding communication, rapport building, and integration of rehabilitation in the home environment. Furthermore, most stroke survivors reported benefit from the intervention, via the acquisition of memory strategies and improved self-confidence through better understanding of their deficits. Overall, telerehabilitation of memory was acceptable to users.

Expansion of the Catalytic Repertoire of Alcohol Dehydrogenases in Plant Metabolism.

Medium-chain alcohol dehydrogenases (ADHs) comprise a highly conserved enzyme family that catalyse the reversible reduction of aldehydes. However, recent discoveries in plant natural product biosynthesis suggest that the catalytic repertoire of ADHs has been expanded. Here we report the crystal structure of dihydroprecondylocarpine acetate synthase (DPAS), an ADH that catalyses the non-canonical 1,4-reduction of an α,ß-unsaturated iminium moiety. Comparison with structures of plant-derived ADHs suggest the 1,4-iminium reduction does not require a proton relay or the presence of a catalytic zinc ion in contrast to canonical 1,2-aldehyde reducing ADHs that require the catalytic zinc and a proton relay. Furthermore, ADHs that catalysed 1,2-iminium reduction required the presence of the catalytic zinc and the loss of the proton relay. This suggests how the ADH active site can be modified to perform atypical carbonyl reductions, providing insight into how chemical reactions are diversified in plant metabolism.

Effect of immunotherapy time-of-day infusion on overall survival among patients with advanced melanoma in the USA (MEMOIR): a propensity score-matched analysis of a single-centre, longitudinal study.

BACKGROUND: The dependence of the adaptive immune system on circadian rhythm is an emerging field of study with potential therapeutic implications. We aimed to determine whether specific time-of-day patterns of immune checkpoint inhibitor infusions might alter melanoma treatment efficacy. METHODS: Melanoma Outcomes Following Immunotherapy (MEMOIR) is a longitudinal study of all patients with melanoma who received ipilimumab, nivolumab, or pembrolizumab, or a combination of these at a single tertiary cancer centre (Winship Cancer Institute of Emory University, Atlanta, GA, USA). For this analysis, we collected deidentified participant-level data from the MEMOIR database for adults (age ≥18 years) diagnosed with stage IV melanoma between 2012 and 2020. Those who received fewer than four infusions were excluded. Standard of care doses were used, with modifications at the treating physicians' discretion. The primary outcome was overall survival, defined as death from any cause and indexed from date of first infusion of immune checkpoint inhibitor. We calculated the association between overall survival and proportion of infusions of immune checkpoint inhibitors received after 1630 h (a composite time cutoff derived from seminal studies of the immune-circadian rhythm to represent onset of evening) using Cox regression and propensity score-matching on age, Eastern Cooperative Oncology Group performance status, serum lactate dehydrogenase concentration, and receipt of corticosteroids and radiotherapy. Treatment-related adverse events that led to change or discontinuation of immune checkpoint inhibitors were also assessed. FINDINGS: Between Jan 1, 2012, and Dec 31, 2020, 481 patients with melanoma received treatment with immune checkpoint inhibitors at the study centre, of whom 299 had stage IV disease and were included in this study; median follow-up was 27 months (IQR 14 to 47). In the complete unmatched sample, 102 (34%) patients were female and 197 (66%) were male, with a median age of 61 years (IQR 51 to 72). Every additional 20% of infusions of immune checkpoint inhibitors received after 1630 h (among all infusions received by a patient) conferred an overall survival hazard ratio (HR) of 1·31 (95% CI 1·00 to 1·71; p=0·046). A propensity score-matched analysis of patients who did (n=73) and did not (n=73) receive at least 20% of their infusions of immune checkpoint inhibitors after 1630 h (54 [37%] of 146 patients were women and 92 [63%] were men, with a median age of 58 years [IQR 48 to 68]) showed that having at least 20% of infusions in the evening was associated with shorter overall survival (median 4·8 years [95% CI 3·9 to not estimable] vs not reached; HR 2·04 [1·04 to 4·00; p=0·038]). This result remained robust to multivariable proportional hazards adjustment with (HR 1·80 [1·08 to 2·98; p=0·023]) and without (2·16 [1·10 to 4·25; p=0·025]) inclusion of the complete unmatched study sample. The most common adverse events were colitis (54 [18%] of 299 patients), hepatitis (27 [9%]), and hypophysitis (15 [5%]), and there were no treatment-related deaths. INTERPRETATION: Our findings are in line with an increasing body of evidence that adaptive immune responses are less robust when initially stimulated in the evening than if stimulated in the daytime. Although prospective studies of the timing of immune checkpoint inhibitor infusions are warranted, efforts towards scheduling infusions before mid-afternoon could be considered in the multidisciplinary management of advanced melanoma. FUNDING: National Institutes of Health, American Society for Radiation Oncology and Melanoma Research Alliance, and Winship Cancer Institute.

Uncoupled activation and cyclization in catmint reductive terpenoid biosynthesis.

Terpene synthases typically form complex molecular scaffolds by concerted activation and cyclization of linear starting materials in a single enzyme active site. Here we show that iridoid synthase, an atypical reductive terpene synthase, catalyzes the activation of its substrate 8-oxogeranial into a reactive enol intermediate, but does not catalyze the subsequent cyclization into nepetalactol. This discovery led us to identify a class of nepetalactol-related short-chain dehydrogenase enzymes (NEPS) from catmint (Nepeta mussinii) that capture this reactive intermediate and catalyze the stereoselective cyclisation into distinct nepetalactol stereoisomers. Subsequent oxidation of nepetalactols by NEPS1 provides nepetalactones, metabolites that are well known for both insect-repellent activity and euphoric effects in cats. Structural characterization of the NEPS3 cyclase reveals that it binds to NAD+ yet does not utilize it chemically for a non-oxidoreductive formal [4 + 2] cyclization. These discoveries will complement metabolic reconstructions of iridoid and monoterpene indole alkaloid biosynthesis.

The growth rate and clinical outcomes of radiation induced meningioma undergoing treatment or active monitoring.

INTRODUCTION: Radiation induced meningioma (RIM) incidence is increasing in line with improved childhood cancer survival. No optimal management strategy consensus exists. This study aimed to delineate meningioma growth rates from tumor discovery and correlate with clinical outcomes. METHODS: Retrospective study of patients with a RIM, managed at a specialist tertiary neuroscience center (2007-2019). Tumor volume was measured from diagnosis and at subsequent interval scans. Meningioma growth rate was determined using a linear mixed-effects model. Clinical outcomes were correlated with growth rates accounting for imaging and clinical prognostic factors. RESULTS: Fifty-four patients (110 meningiomas) were included. Median duration of follow-up was 74 months (interquartile range [IQR], 41-102 months). Mean radiation dose was 41 Gy (standard deviation [SD] = 14.9) with a latency period of 34.4 years (SD = 13.7). Median absolute growth rate was 0.62 cm3/year and the median relative growth rate was 72%/year. Forty meningiomas (between 27 patients) underwent surgical intervention after a median follow-up duration of 4 months (IQR 2-35). Operated RIMs were clinically aggressive, likely to be WHO grade 2 at first resection (43.6%) and to progress after surgery (41%). Median time to progression was 28 months (IQR 13-60.5). A larger meningioma at discovery was associated with growth (HR 1.2 [95% CI 1.0-1.5], P = 0.039) but not progression after surgery (HR 2.2 [95% CI 0.7-6.6], P = 0.181). Twenty-seven (50%) patients had multiple meningiomas by the end of the study. CONCLUSION: RIMs exhibit high absolute and relative growth rates after discovery. Surgery is recommended for symptomatic or rapidly growing meningiomas only. Recurrence risk after surgery is high.