Bacterial Leaf Spot Susceptibility Screening of Chili Pepper Cultivars Using qPCR Determination of Xanthomonas euvesicatoria pv. euvesicatoria Titers.

Bacterial leaf spot is a serious disease of chili pepper (Capsicum spp.) caused by Xanthomonas euvesicatoria pv. euvesicatoria. Conventional resistance screening is time and resource intensive. It was considered that a quick and simple determination of cultivar susceptibility could be achieved through estimating bacterial titers of inoculated plants. A SYBR quantitative polymerase chain reaction (qPCR)-based assay was compared with conventional PCR, then used to detect and enumerate pathogen titers in serial dilutions and DNA extracted from infected plant leaves. The qPCR detection limit was approximately 1 CFU µl-1, 10 times more sensitive than conventional PCR. A linear correlation (R2 = 0.994) was obtained from the standard curve comparing plate-truthed serial dilutions of the pathogen with the qPCR cycle threshold. Six strains were used to inoculate cultivars Hugo and Warlock. One strain, X. euvesicatoria pv. euvesicatoria BRIP62403, was consistently the most virulent based on visual symptoms and pathogen titers in planta inferred by qPCR performed on DNA extracted from infected leaves 2 and 6 weeks postinoculation. Visual observations 6 weeks after inoculation were highly correlated (R2 = 0.8254) to pathogen titers. The qPCR method was used to categorize 20 chili pepper cultivars 2 weeks after inoculation. A high positive correlation (R2 = 0.6826) was observed between visual scoring and pathogen titers from 20 chili pepper cultivars, facilitating categorization of susceptible, intermediate, and resistant cultivars. The qPCR approach developed here facilitates susceptibility screening of chili pepper cultivars at an early stage of selection and could be readily adapted to a range of other pathosystems.

Pharmacokinetic effects of a single-dose nutritional ketone ester supplement on brain ketone and glucose metabolism in alcohol use disorder - a pilot study.

Introduction: Acute alcohol intake decreases brain glucose metabolism and increases brain uptake of acetate, a metabolite of alcohol. Individuals with alcohol use disorder (AUD) show elevated brain acetate metabolism at the expense of glucose, a shift in energy utilization that persists beyond acute intoxication. We recently reported that nutritional ketosis and administration of ketone bodies as an alternative energy source to glucose reduce alcohol withdrawal severity and alcohol craving in AUD. However, the regional effects of nutritional ketosis on brain ketone (beta-hydroxybutyrate [BHB]) and glucose metabolism have not been studied in AUD. Methods: Five participants with AUD underwent two magnetic resonance imaging (MRI) sessions and 4 participants with AUD underwent two positron emission tomography (PET) sessions with 18 F-fluorodeoxyglucose. All participants completed one session without KE intervention and one session during which they consumed 395 mg/kg (R) -3-hydroxybutyl (R) -3-hydroxybutyrate Ketone Ester (KE) intervention (TdeltaS Global Inc.) before the scan. The order of the sessions was randomized. For the PET cohort, blood glucose and ketone levels were assessed and voxel-wise maps of the cerebral metabolic rate of glucose (CMRglc) were computed at each session. For the MRI cohort, brain anterior cingulate BHB levels were assessed using magnetic resonance spectroscopy. Results: A single dose of KE elevated blood BHB and anterior cingulate BHB levels compared to baseline. Moreover, blood glucose levels were lower with KE than baseline, and whole-brain CMRglc decreased by 17%. The largest KE-induced CMRglc reductions were in the frontal, occipital, cortex, and anterior cingulate cortices. Conclusion: These findings provide preliminary evidence that KE administration elevates ketone and reduces brain glucose metabolism in humans, consistent with a shift from glucose to ketones as a brain energy source. Average reductions in CMRglc of 17% are similar to global average reductions documented with administration of 0.25-0.5 g/kg of alcohol. Documenting the clinical and neurometabolic effects of nutritional ketosis will yield fundamental knowledge as to its potential beneficial effects as a treatment for AUD and its underlying neural mechanisms.

Chinee Apple (Ziziphus mauritiana): A Comprehensive Review of Its Weediness, Ecological Impacts and Management Approaches.

Ziziphus mauritiana Lam. (Rhamnaceae) (Chinee Apple, Indian Jujube, or Ber) is a significant woody weed in the drier tropics of northern Queensland, Western Australia, and the Northern Territory. Throughout these regions, its densely formed thickets influence the structure, function, and composition of rangeland ecosystems by outcompeting native pasture species. Despite this, the recent literature is heavily focused on the horticultural value of domesticated Ziziphus species in South Asia (China, India, and Pakistan), particularly its potential for poverty alleviation in arid or semi-arid areas. In fact, there has been comparatively little research undertaken on its invasiveness or associated ecological factors in pastoral contexts. Currently, the management of Z. mauritiana is limited to the application of synthetic herbicides or mechanical clearing operations. There is also considerable interest in the exploitation of host-specific, natural enemies (biological control agents, herbivorous insects, fungi, bacteria, or viruses) for limiting the vigour, competitiveness, or reproductive capacity of Z. mauritiana in northern Australia. The development of a "bioherbicide" in lieu of synthetic counterparts may foster a more resilient coexistence between agricultural systems and the natural environment owing to its reduced environmental persistence and increased target specificity. This review summarises the current literature on the weediness, ecological impacts, and current management of this problematic weed, thereby identifying (i) opportunities for further research and (ii) recommendations for improved management within its invasive range.

Molecular Imaging of Pulmonary Inflammation in Users of Electronic and Combustible Cigarettes: A Pilot Study.

Electronic cigarette (EC) use has increased dramatically, particularly among adolescents and young adults, and, like cigarette use, can cause pulmonary inflammation and increase the risk of lung disease. Methods: This preliminary study used PET with 18F-6-(1/2)(2-fluoro-propyl)-4-methylpyridin-2-amine (18F-NOS) to quantify inducible nitric oxide synthase expression to characterize oxidative stress and inflammation in the lungs in vivo in 3 age- and sex-matched groups: 5 EC users, 5 cigarette smokers, and 5 controls who had never smoked or vaped. Results: EC users showed greater 18F-NOS nondisplaceable binding potential (BPND) than cigarette smokers (P = 0.03) and controls (P = 0.01), whereas BPND in cigarette smokers did not differ from that in controls (P > 0.1). 18F-NOS lung tissue delivery and inducible nitric oxide synthase distribution volume did not significantly differ among groups. Although there were no group differences in peripheral inflammatory biomarker concentrations, 18F-NOS BPND correlated with the proinflammatory cytokine tumor necrosis factor-α concentrations (rs = 0.87, P = 0.05) in EC users. Additionally, when EC users and cigarette smokers were pooled together, number of vaping episodes or cigarettes per day correlated with interleukin-6 levels (rs = 0.86, P = 0.006). Conclusion: This is the first PET imaging study to compare lung inflammation between EC and cigarette users in vivo. We found preliminary evidence that EC users have greater pulmonary inflammation than cigarette smokers and controls, with a positive association between pulmonary and peripheral measures of inflammation.

Distinguishing Progression from Pseudoprogression in Glioblastoma Using 18F-Fluciclovine PET.

Accurate differentiation between tumor progression (TP) and pseudoprogression remains a critical unmet need in neurooncology. 18F-fluciclovine is a widely available synthetic amino acid PET radiotracer. In this study, we aimed to assess the value of 18F-fluciclovine PET for differentiating pseudoprogression from TP in a prospective cohort of patients with suspected radiographic recurrence of glioblastoma. Methods: We enrolled 30 glioblastoma patients with radiographic progression after first-line chemoradiotherapy for whom surgical resection was planned. The patients underwent preoperative 18F-fluciclovine PET and MRI. The relative percentages of viable tumor and therapy-related changes observed in histopathology were quantified and categorized as TP (≥50% viable tumor), mixed TP (<50% and >10% viable tumor), or pseudoprogression (≤10% viable tumor). Results: Eighteen patients had TP, 4 had mixed TP, and 8 had pseudoprogression. Patients with TP/mixed TP had a significantly higher 40- to 50-min SUVmax (6.64 + 1.88 vs. 4.11 ± 1.52, P = 0.009) than patients with pseudoprogression. A 40- to 50-min SUVmax cutoff of 4.66 provided 90% sensitivity and 83% specificity for differentiation of TP/mixed TP from pseudoprogression (area under the curve [AUC], 0.86). A maximum relative cerebral blood volume cutoff of 3.672 provided 90% sensitivity and 71% specificity for differentiation of TP/mixed TP from pseudoprogression (AUC, 0.779). Combining a 40- to 50-min SUVmax cutoff of 4.66 and a maximum relative cerebral blood volume of 3.67 on MRI provided 100% sensitivity and 80% specificity for differentiating TP/mixed TP from pseudoprogression (AUC, 0.95). Conclusion: 18F-fluciclovine PET uptake can accurately differentiate pseudoprogression from TP in glioblastoma, with even greater accuracy when combined with multiparametric MRI. Given the wide availability of 18F-fluciclovine, larger, multicenter studies are warranted to determine whether amino acid PET with 18F-fluciclovine should be used in the routine posttreatment assessment of glioblastoma.

Insertion of 4-Demethylwyosine in tRNAPhe Catalyzed by the Radical S-Adenosyl-l-methionine Enzyme TYW1 Entails Oxidative Cleavage of Pyruvate to Form CO2.

The radical S-adenosyl-l-methionine (SAM) enzyme TYW1 catalyzes the condensation of C-2 and C-3 atoms of pyruvate with N-methylguanosine containing tRNAPhe to form 4-demethylwyosine (imG-14) modified tRNAPhe. The fate of C-1 is not known, and either formate or carbon dioxide (CO2) has been proposed. In this study, a coupled assay that transforms either CO2 or formate to oxaloacetate (OAA) was used to determine the fate of C-1. In the presence of [1-13C1]-pyruvate, 13C-enriched OAA was observed in a process that is concomitant with the formation of imG-14, under conditions that preferentially transform CO2 and not formate to OAA. These findings are discussed in the context of the cofactor content of TYW1 and a new role for the auxiliary cluster in catalyzing the oxidative cleavage of C-1-C-2 bond of pyruvate in the catalytic cycle of TYW1.

[18F]NOS PET Brain Imaging Suggests Elevated Neuroinflammation in Idiopathic Parkinson's Disease.

Neuroinflammation is implicated as a key pathologic mechanism in many neurodegenerative diseases and is thought to be mediated in large part by microglia, native phagocytic immune cells of the CNS. Abnormal aggregation of the protein α-synuclein after phagocytosis by microglia is one possible neuropathophysiological mechanism driving Parkinson's disease (PD). We conducted a human pilot study to evaluate the feasibility of targeting the inducible isoform of nitric oxide synthase using the [18F]NOS radiotracer to measure neuroinflammation in idiopathic PD. Ten adults consisting of 6 PD patients and 4 healthy controls (HC) underwent one hour of dynamic [18F]NOS positron emission tomography (PET) brain imaging with arterial blood sampling. We observed increased [18F]NOS whole brain distribution volume (VT) in PD patients compared to age-matched healthy controls (p < 0.008) via a 1-tissue compartment (TC) model. The rate constant K1 for transport from blood into tissue did not differ between groups (p = 0.72). These findings suggest elevated oxidative stress, a surrogate marker of inflammation, is present in early-stage idiopathic PD and indicate that [18F]NOS PET imaging is a promising, non-invasive method to measure neuroinflammation.

Draft Genome Sequences of Dickeya Species Associated with Soft Rot Diseases in Pineapple (Ananas comosus) and Banana (Musa spp.).

Dickeya species cause soft rots on many commercial crops. Here, we present the draft genomes of Dickeya oryzae (BRIP 64262) and Dickeya zeae (BRIP 64263) isolates causing soft rot on banana (Musa spp.) and pineapple (Ananas comosus) plants, respectively. This expands the range of available genomes from plant-pathogenic Dickeya species.

Elucidation of the substrate of tRNA-modifying enzymes MnmEG leads to in vitro reconstitution of an evolutionarily conserved uridine hypermodification.

The evolutionarily conserved bacterial proteins MnmE and MnmG collectively install a carboxymethylaminomethyl (cmnm) group at the fifth position of wobble uridines of several tRNA species. While the reaction catalyzed by MnmEG is one of the central steps in the biosynthesis of the methylaminomethyl (mnm) posttranscriptional tRNA modification, details of the reaction remain elusive. Glycine is known to be the source of the carboxy methylamino moiety of cmnm, and a tetrahydrofolate (THF) analog is thought to supply the one carbon that is appended to the fifth position of U. However, the nature of the folate analog remains unknown. This article reports the in vitro biochemical reconstitution of the MnmEG reaction. Using isotopically labeled methyl and methylene THF analogs, we demonstrate that methylene THF is the true substrate. We also show that reduced FAD is required for the reaction and that DTT can replace the NADH in its role as a reductant. We discuss the implications of these methylene-THF and reductant requirements on the mechanism of this key tRNA modification catalyzed by MnmEG.

A Pan-Global Study of Bacterial Leaf Spot of Chilli Caused by Xanthomonas spp.

Bacterial Leaf Spot (BLS) is a serious bacterial disease of chilli (Capsicum spp.) caused by at least four different Xanthomonas biotypes: X. euvesicatoria pv. euvesicatoria, X. euvesicatoria pv. perforans, X. hortorum pv. gardneri, and X. vesicatoria. Symptoms include black lesions and yellow halos on the leaves and fruits, resulting in reports of up to 66% losses due to unsalable and damaged fruits. BLS pathogens are widely distributed in tropical and subtropical regions. Xanthomonas is able to survive in seeds and crop residues for short periods, leading to the infections in subsequent crops. The pathogen can be detected using several techniques, but largely via a combination of traditional and molecular approaches. Conventional detection is based on microscopic and culture observations, while a suite of Polymerase Chain Reaction (PCR) and Loop-Mediated Isothermal Amplification (LAMP) assays are available. Management of BLS is challenging due to the broad genetic diversity of the pathogens, a lack of resilient host resistance, and poor efficacy of chemical control. Some biological control agents have been reported, including bacteriophage deployment. Incorporating stable host resistance is a critical component in ongoing integrated management for BLS. This paper reviews the current status of BLS of chilli, including its distribution, pathogen profiles, diagnostic options, disease management, and the pursuit of plant resistance.

Draft Genome Sequences of Robbsia andropogonis Isolated from Sorghum bicolor Exhibiting Bacterial Leaf Stripe in Australia.

Robbsia andropogonis causes leaf spots, streaks, or stripes on a wide range of commercially important crops. Here, we present the draft genome sequences of two isolates of R. andropogonis sourced from Sorghum bicolor displaying symptoms of bacterial leaf stripe disease in Australia.

Imaging sensitive and drug-resistant bacterial infection with [11C]-trimethoprim.

BACKGROUNDSeveral molecular imaging strategies can identify bacterial infections in humans. PET affords the potential for sensitive infection detection deep within the body. Among PET-based approaches, antibiotic-based radiotracers, which often target key bacterial-specific enzymes, have considerable promise. One question for antibiotic radiotracers is whether antimicrobial resistance (AMR) reduces specific accumulation within bacteria, diminishing the predictive value of the diagnostic test.METHODSUsing a PET radiotracer based on the antibiotic trimethoprim (TMP), [11C]-TMP, we performed in vitro uptake studies in susceptible and drug-resistant bacterial strains and whole-genome sequencing (WGS) in selected strains to identify TMP resistance mechanisms. Next, we queried the NCBI database of annotated bacterial genomes for WT and resistant dihydrofolate reductase (DHFR) genes. Finally, we initiated a first-in-human protocol of [11C]-TMP in patients infected with both TMP-sensitive and TMP-resistant organisms to demonstrate the clinical feasibility of the tool.RESULTSWe observed robust [11C]-TMP uptake in our panel of TMP-sensitive and -resistant bacteria, noting relatively variable and decreased uptake in a few strains of P. aeruginosa and E. coli. WGS showed that the vast majority of clinically relevant bacteria harbor a WT copy of DHFR, targetable by [11C]-TMP, and that despite the AMR, these strains should be "imageable." Clinical imaging of patients with [11C]-TMP demonstrated focal radiotracer uptake in areas of infectious lesions.CONCLUSIONThis work highlights an approach to imaging bacterial infection in patients, which could affect our understanding of bacterial pathogenesis as well as our ability to better diagnose infections and monitor response to therapy.TRIAL REGISTRATIONClinicalTrials.gov NCT03424525.FUNDINGInstitute for Translational Medicine and Therapeutics, Burroughs Wellcome Fund, NIH Office of the Director Early Independence Award (DP5-OD26386), and University of Pennsylvania NIH T32 Radiology Research Training Grant (5T32EB004311-12).

Impact of Annealing and Controlled Ice Nucleation on Properties of A Lyophilized 50 mg/ml MAB Formulation.

We compared "ice-fog" controlled ice nucleation at -6 °C to annealing at the same temperature for a 50 mg/mL monoclonal antibody formulation, using shelf-ramp freezing as a control. Cake structure, drying time, reconstitution time, specific surface area, calculated cake resistance and size exclusion chromatography were all compared. Controlled nucleation resulted in the fastest reconstitution, shortest primary drying, lowest calculated cake resistance, lowest specific surface area and highest moisture content. There was no effect upon the results for size exclusion chromatography. Results for annealing were between those for controlled nucleation and shelf-ramp freezing. All results were consistent with "ice-fog" controlled nucleation at -6 °C having greater impact upon the ice crystal morphology than annealing at the same temperature for 3 h.

Preliminary Evaluation of 68Ga-P16-093, a PET Radiotracer Targeting Prostate-Specific Membrane Antigen in Prostate Cancer.

PURPOSE: Prostate-specific membrane antigen (PSMA) is a promising molecular target for imaging of prostate adenocarcinoma. 68Ga-P16-093, a small molecule PSMA ligand, previously showed equivalent diagnostic performance compared to 68Ga-PSMA-11 PET/CT in a pilot study of prostate cancer patients with biochemical recurrence (BCR). We performed a pilot study for further characterization of 68Ga-P16-093 including comparison to conventional imaging. PROCEDURES: Patients were enrolled into two cohorts. The biodistribution cohort included 8 treated prostate cancer patients without recurrence, who underwent 6 whole body PET/CT scans with urine sampling for dosimetry using OLINDA/EXM. The dynamic cohort included 15 patients with BCR and 2 patients with primary prostate cancer. Two patients with renal cell carcinoma were also enrolled for exploratory use. A dynamic PET/CT was followed by 2 whole body scans for imaging protocol optimization based on bootstrapped replicates. 68Ga-P16-093 PET/CT was compared for diagnostic performance against available 18F-fluciclovine PET/CT, 99mTc-MDP scintigraphy, diagnostic CT, and MRI. RESULTS: 68Ga-P16-093 deposited similar effective dose (0.024 mSv/MBq) and lower urinary bladder dose (0.064 mSv/MBq) compared to 68Ga-PSMA-11. The kidneys were the critical organ (0.290 mSv/MBq). While higher injected activities were preferable, lower injected activities at 74-111 MBq (2-3 mCi) yielded 80% retention in signal-to-noise ratio. The optimal injection-to-scan interval was 60 min, with acceptable delay up to 90 min. 68Ga-P16-093 PET/CT showed superior diagnostic performance over conventional imaging with overall patient-level lesion detection rate of 71%, leading to a change in management in 42% of the patients. CONCLUSIONS: Based on its favorable imaging characteristics and diagnostic performance in prostate cancer, 68Ga-P16-093 PET/CT merits further investigation in larger clinical studies.

Molecular, Phenotypical, and Host-Range Characterization of Robbsia andropogonis Strains Isolated from Bougainvillea spp. in Mexico.

Characteristic leaf spot and blight symptoms caused by Robbsia andropogonis on bougainvillea plants were found in three locations in different provinces of Mexico from 2019 to 2020. Eleven bacterial isolates with morphology similar to R. andropogonis were obtained from the diseased bougainvillea leaves. The isolates were confirmed as R. andropogonis by phenotypic tests and 16S rRNA, rpoD, and gyrB gene sequencing. In addition to bougainvillea, the strains were pathogenic to 10 agriculturally significant crops, including maize (Zea mays), sorghum (Sorghum bicolor), barley (Hordeum vulgare), coffee (Coffea arabiga), carnation (Dianthus caryophilus), Mexican lime (Citrus × aurantifolia), common bean (Phaseolus vulgaris), broadbeans (Vicia faba), and pea (Pisum sativum), but not runner bean (Phaseolus coccineus). The haplotypes network reveals the genetic variability among Mexican strains and its phylogeographic relationship with Japan, the U.S.A., and China. The presence of this pathogen represents a challenge for plant protection strategies in Mexico.

Kinetic and Static Analysis of Poly-(Adenosine Diphosphate-Ribose) Polymerase-1-Targeted 18F-Fluorthanatrace PET Images of Ovarian Cancer.

The poly-(adenosine diphosphate-ribose) polymerase (PARP) family of proteins participates in numerous functions, most notably the DNA damage response. Cancer vulnerability to DNA damage has led to development of several PARP inhibitors (PARPi). This class of drugs has demonstrated therapeutic efficacy in ovarian, breast, and prostate cancers, but with variable response. Consequently, clinics need to select patients likely to benefit from these targeted therapies. In vivo imaging of 18F-fluorthanatrace uptake has been shown to correspond to PARP-1 expression in tissue. This study characterized the pharmacokinetics of 18F-fluorthanatrace and tested kinetic and static models to guide metric selection in future studies assessing 18F-fluorthanatrace as a biomarker of response to PARPi therapy. Methods: Fourteen prospectively enrolled ovarian cancer patients were injected with 18F-fluorthanatrace and imaged dynamically for 60 min after injection followed by up to 2 whole-body scans, with venous blood activity and metabolite measurements. SUVmax and SUVpeak were extracted from dynamic images and whole-body scans. Kinetic parameter estimates and SUVs were assessed for correlations with tissue PARP-1 immunofluorescence (n = 7). Simulations of population kinetic parameters enabled estimation of measurement bias and precision in parameter estimates. Results:18F-fluorthanatrace blood clearance was variable, but labeled metabolite profiles were similar across patients, supporting use of a population parent fraction curve. The total distribution volume from a reversible 2-tissue-compartment model and Logan reference tissue distribution volume ratio (DVR) from the first hour of PET acquisition correlated with tumor PARP-1 expression by immunofluorescence (r = 0.76 and 0.83, respectively; P < 0.05). DVR bias and precision estimates were 6.4% and 29.1%, respectively. SUVmax and SUVpeak acquired from images with midpoints of 57.5, 110 ± 3, and 199 ± 4 min highly correlated with PARP-1 expression (mean ± SD, r ≥ 0.79; P < 0.05). Conclusion: Tumor SUVmax and SUVpeak at 55-60 min after injection and later and DVR from at least 60 min appear to be robust noninvasive measures of PARP-1 binding. 18F-fluorthanatrace uptake in ovarian cancer was best described by models of reversible binding. However, pharmacokinetic patterns of tracer uptake were somewhat variable, especially at later time points.

New Role for Radical SAM Enzymes in the Biosynthesis of Thio(seleno)oxazole RiPP Natural Products.

Ribosomally synthesized post-translationally modified peptides (RiPPs) are ubiquitous and represent a structurally diverse class of natural products. The ribosomally encoded precursor polypeptides are often extensively modified post-translationally by enzymes that are encoded by coclustered genes. Radical S-adenosyl-l-methionine (SAM) enzymes catalyze numerous chemically challenging transformations. In RiPP biosynthetic pathways, these transformations include the formation of C-H, C-C, C-S, and C-O linkages. In this paper, we show that the Geobacter lovleyi sbtM gene encodes a radical SAM protein, SbtM, which catalyzes the cyclization of a Cys/SeCys residue in a minimal peptide substrate. Biochemical studies of this transformation support a mechanism involving H-atom abstraction at the C-3 of the substrate Cys to initiate the chemistry. Several possible cyclization products were considered. The collective biochemical, spectroscopic, mass spectral, and computational observations point to a thiooxazole as the product of the SbtM-catalyzed modification. To our knowledge, this is the first example of a radical SAM enzyme that catalyzes a transformation involving a SeCys-containing peptide and represents a new paradigm for formation of oxazole-containing RiPP natural products.

Astrocyte activation imaging with 11C-acetate and amyloid PET in mild cognitive impairment due to Alzheimer pathology.

BACKGROUND: Neuroinflammation is a well-known feature of early Alzheimer disease (AD) yet astrocyte activation has not been extensively evaluated with in vivo imaging in mild cognitive impairment (MCI) due to amyloid plaque pathology. Unlike neurons, astrocytes metabolize acetate, which has potential as a glial biomarker in neurodegeneration in response to AD pathologic features. Since the medial temporal lobe (MTL) is a hotspot for AD neurodegeneration and inflammation, we assessed astrocyte activity in the MTL and compared it to amyloid and cognition. METHODS: We evaluate spatial patterns of in vivo astrocyte activation and their relationships to amyloid deposition and cognition in a cross-sectional pilot study of six participants with MCI and five cognitively normal participants. We measure 11C-acetate and 18F-florbetaben amyloid standardized uptake values ratios (SUVRs) and kinetic flux compared to the cerebellum on PET, with MRI and neurocognitive testing. RESULTS: MTL 11C-acetate SUVR was significantly elevated in MCI compared to cognitively normal participants (P = 0.03; Cohen d = 1.76). Moreover, MTL 11C-acetate SUVR displayed significant associations with global and regional amyloid burden in MCI. Greater MTL 11C-acetate retention was significantly related with worse neurocognitive measures including the Montreal Cognitive Assessment (P = 0.001), word list recall memory (P = 0.03), Boston naming test (P = 0.04) and trails B test (P = 0.04). CONCLUSIONS: While further validation is required, this exploratory pilot study suggests a potential role for 11C-acetate PET as a neuroinflammatory biomarker in MCI and early AD to provide clinical and translational insights into astrocyte activation as a pathological response to amyloid.

Whole-Genome Data from Curtobacterium flaccumfaciens pv. flaccumfaciens Strains Associated with Tan Spot of Mungbean and Soybean Reveal Diverse Plasmid Profiles.

Despite the substantial economic impact of Curtobacterium flaccumfaciens pv. flaccumfaciens on legume production worldwide, the genetic basis of its pathogenicity and potential host association is poorly understood. The production of high-quality reference genome assemblies of C. flaccumfaciens pv. flaccumfaciens strains associated with different hosts sheds light on the genetic basis of its pathogenic variability and host association. Moreover, the study of recent outbreaks of bacterial wilt and microevolution of the pathogen in Australia requires access to high-quality reference genomes that are sufficiently closely related to the population being studied within Australia. We provide the first genome assemblies of C. flaccumfaciens pv. flaccumfaciens strains associated with mungbean and soybean, which revealed high variability in their plasmid composition. The analysis of C. flaccumfaciens pv. flaccumfaciens genomes revealed an extensive suite of carbohydrate-active enzymes potentially associated with pathogenicity, including four carbohydrate esterases, 50 glycoside hydrolases, 23 glycosyl transferases, and a polysaccharide lyase. We also identified 11 serine peptidases, three of which were located within a linear plasmid, pCff119. These high-quality assemblies and annotations will provide a foundation for population genomics studies of C. flaccumfaciens pv. flaccumfaciens in Australia and for answering fundamental questions regarding pathogenicity factors and adaptation of C. flaccumfaciens pv. flaccumfaciens to various hosts worldwide and, at a broader scale, contribute to unraveling genomic features of gram-positive, xylem-inhabiting bacterial pathogens.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Eukaryotic TYW1 Is a Radical SAM Flavoenzyme.

TYW1 is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the condensation of pyruvate and N-methylguanosine-containing tRNAPhe, forming 4-demethylwyosine-containing tRNAPhe. Homologues of TYW1 are found in both archaea and eukarya; archaeal homologues consist of a single domain, while eukaryal homologues contain a flavin binding domain in addition to the radical SAM domain shared with archaeal homologues. In this study, TYW1 from Saccharomyces cerevisiae (ScTYW1) was heterologously expressed in Escherichia coli and purified to homogeneity. ScTYW1 is purified with 0.54 ± 0.07 and 4.2 ± 1.9 equiv of flavin mononucleotide (FMN) and iron, respectively, per mole of protein, suggesting the protein is ∼50% replete with Fe-S clusters and FMN. While both NADPH and NADH are sufficient for activity, significantly more product is observed when used in combination with flavin nucleotides. ScTYW1 is the first example of a radical SAM flavoenzyme that is active with NAD(P)H alone.