190 research outputs found

    Phylogenetic relationships within Orobanche and Phelipanche (Orobanchaceae) from Central Europe, focused on problematic aggregates, taxonomy, and host ranges

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    Holoparasitic genera within the family Orobanchaceae are characterized by greatly reduced vegetative organs; therefore, molecular analysis has proved to be a useful tool in solving taxonomic problems in this family. For this purpose, we studied all species of the genera Orobanche and Phelipanche occurring in Central Europe, specifically in Poland, the Czech Republic, Slovakia, and Austria, supplemented by samples mainly from Spain, France, Germany, and Ukraine. They were investigated using nuclear sequences (ITS region) and a plastid trnL- trnF region. The aim of this study was to examine phylogenetic relationships within Orobanche and Phelipanche from Central Europe; we focused on problematic species and aggregates, recent taxonomic changes in these (rank and secondary ranks), and host ranges. The most interesting results concern the exlusion of O. mayeri from O. alsatica aggr. Additionally, following the rules of traditional taxonomy, the correct names and types of some secondary ranks are given and, as a result of this, a new combination below the Phelipanche genus is made ( P . sect. Trionychon ). The host ranges of the investigated species in Central Europe include 102 species from 12 families, most often from Asteraceae. For this purpose, ca. 400 localities were examined in the field. Moreover, data acquired from the literature and European and Asian herbaria were use

    Scaffold-Based [Fe]-Hydrogenase Model: H\u3csub\u3e2\u3c/sub\u3e Activation Initiates Fe(0)-Hydride Extrusion and Non-Biomimetic Hydride Transfer

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    We report the synthesis and reactivity of a model of [Fe]-hydrogenase derived from an anthracene-based scaffold that includes the endogenous, organometallic acyl(methylene) donor. In comparison to other non-scaffolded acyl-containing complexes, the complex described herein retains molecularly well-defined chemistry upon addition of multiple equivalents of exogenous base. Clean deprotonation of the acyl(methylene) C-H bond with a phenolate base results in the formation of a dimeric motif that contains a new Fe-C(methine) bond resulting from coordination of the deprotonated methylene unit to an adjacent iron center. This effective second carbanion in the ligand framework was demonstrated to drive heterolytic H2 activation across the Fe(ii) center. However, this process results in reductive elimination and liberation of the ligand to extrude a lower-valent Fe-carbonyl complex. Through a series of isotopic labelling experiments, structural characterization (XRD, XAS), and spectroscopic characterization (IR, NMR, EXAFS), a mechanistic pathway is presented for H2/hydride-induced loss of the organometallic acyl unit (i.e. pyCH2-CO → pyCH3+CO). The known reduced hydride species [HFe(CO)4]– and [HFe3(CO)11]– have been observed as products by 1H/2H NMR and IR spectroscopies, as well as independent syntheses of PNP[HFe(CO)4]. The former species (i.e. [HFe(CO)4]–) is deduced to be the actual hydride transfer agent in the hydride transfer reaction (nominally catalyzed by the title compound) to a biomimetic substrate ([TolIm](BArF) = fluorinated imidazolium as hydride acceptor). This work provides mechanistic insight into the reasons for lack of functional biomimetic behavior (hydride transfer) in acyl(methylene)pyridine based mimics of [Fe]-hydrogenase

    An Improved Upper Bound for the Ring Loading Problem

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    The Ring Loading Problem emerged in the 1990s to model an important special case of telecommunication networks (SONET rings) which gained attention from practitioners and theorists alike. Given an undirected cycle on nn nodes together with non-negative demands between any pair of nodes, the Ring Loading Problem asks for an unsplittable routing of the demands such that the maximum cumulated demand on any edge is minimized. Let LL be the value of such a solution. In the relaxed version of the problem, each demand can be split into two parts where the first part is routed clockwise while the second part is routed counter-clockwise. Denote with LL^* the maximum load of a minimum split routing solution. In a landmark paper, Schrijver, Seymour and Winkler [SSW98] showed that LL+1.5DL \leq L^* + 1.5D, where DD is the maximum demand value. They also found (implicitly) an instance of the Ring Loading Problem with L=L+1.01DL = L^* + 1.01D. Recently, Skutella [Sku16] improved these bounds by showing that LL+1914DL \leq L^* + \frac{19}{14}D, and there exists an instance with L=L+1.1DL = L^* + 1.1D. We contribute to this line of research by showing that LL+1.3DL \leq L^* + 1.3D. We also take a first step towards lower and upper bounds for small instances

    Eosinophilic esophagitis in cystic fibrosis: A case series and review of the literature

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    Patients with cystic fibrosis (CF) frequently experience gastrointestinal symptoms including nausea, emesis, malnutrition and indigestion; diseases such as gastroesophageal reflux disease (GERD), distal intestinal obstructive syndrome, and cholelithiasis are commonly implicated. We have recently diagnosed eosinophilic esophagitis (EoE) in three patients with CF. EoE is a TH-2 driven, allergen-mediated disease which causes esophageal eosinophilia and presents with symptoms of nausea, feeding intolerance, regurgitation, and dysphagia. EoE is diagnosed when esophageal biopsies reveal greater than 15 eosinophils per high power field in the setting of the appropriate clinical scenario and after exclusion of other causes of esophageal eosinophilia. Although described with increasing frequently in the gastrointestinal literature, there have been no prior cases documenting the co-existence of EoE and CF. We speculate that this is related to lack of familiarity with EoE symptoms by CF providers. We present three patients with CF diagnosed with EoE and review the current literature regarding diagnosis and management, focusing on management issues in patients with CF

    Comparison of single breath hyperpolarized 129Xe MRI with dynamic 19F MRI in cystic fibrosis lung disease

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    Purpose: To quantitatively compare dynamic 19F and single breath hyperpolarized 129Xe MRI for the detection of ventilation abnormalities in subjects with mild cystic fibrosis (CF) lung disease. Methods: Ten participants with stable CF and a baseline FEV1 > 70% completed a single imaging session where dynamic 19F and single breath 129Xe lung ventilation images were acquired on a 3T MRI scanner. Ventilation defect percentages (VDP) values between 19F early-breath, 19F maximum-ventilation, 129Xe low-resolution, and 129Xe high-resolution images were compared. Dynamic 19F images were used to determine gas wash-in/out rates in regions of ventilation congruency and mismatch between 129Xe and 19F. Results: VDP values from high-resolution 129Xe images were greater than from low-resolution images (P =.001), although these values were significantly correlated (r = 0.68, P =.03). Early-breath 19F VDP and max-vent 19F VDP also showed significant correlation (r = 0.75, P =.012), with early-breath 19F VDP values being significantly greater (P <.001). No correlation in VDP values were detected between either 19F method or high-res 129Xe images. In addition, the location and volume of ventilation defects were often different when comparing 129Xe and 19F images from the same subject. Areas of ventilation congruence displayed the expected ventilation kinetics, while areas of ventilation mismatch displayed abnormally slow gas wash-in and wash-out. Conclusion: In CF subjects, ventilation abnormalities are identified by both 19F and HP 129Xe imaging. However, these ventilation abnormalities are not entirely congruent. 19F and HP 129Xe imaging provide complementary information that enable differentiation of normally ventilated, slowly ventilated, and non-ventilated regions in the lungs

    Targeting the spliceosome through RBM39 degradation results in exceptional responses in high-risk neuroblastoma models

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    Aberrant alternative pre-mRNA splicing plays a critical role in MYC-driven cancers and therefore may represent a therapeutic vulnerability. Here, we show that neuroblastoma, a MYC-driven cancer characterized by splicing dysregulation and spliceosomal dependency, requires the splicing factor RBM39 for survival. Indisulam, a "molecular glue"that selectively recruits RBM39 to the CRL4-DCAF15 E3 ubiquitin ligase for proteasomal degradation, is highly efficacious against neuroblastoma, leading to significant responses in multiple high-risk disease models, without overt toxicity. Genetic depletion or indisulam-mediated degradation of RBM39 induces significant genome-wide splicing anomalies and cell death. Mechanistically, the dependency on RBM39 and high-level expression of DCAF15 determine the exquisite sensitivity of neuroblastoma to indisulam. Our data indicate that targeting the dysregulated spliceosome by precisely inhibiting RBM39, a vulnerability in neuroblastoma, is a valid therapeutic strategy

    Marine Myxobacteria as a Source of Antibiotics—Comparison of Physiology, Polyketide-Type Genes and Antibiotic Production of Three New Isolates of Enhygromyxa salina

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    Three myxobacterial strains, designated SWB004, SWB005 and SWB006, were obtained from beach sand samples from the Pacific Ocean and the North Sea. The strains were cultivated in salt water containing media and subjected to studies to determine their taxonomic status, the presence of genes for the biosynthesis of polyketides and antibiotic production. 16S rDNA sequence analysis revealed the type strain Enhygromyxa salina SHK-1T as their closest homolog, displaying between 98% (SWB005) and 99% (SWB004 and SWB006) sequence similarity. All isolates were rod-shaped cells showing gliding motility and fruiting body formation as is known for myxobacteria. They required NaCl for growth, with an optimum concentration of around 2% [w/v]. The G + C-content of genomic DNA ranged from 63.0 to 67.3 mol%. Further, the strains were analyzed for their potential to produce polyketide-type structures. PCR amplified ketosynthase-like gene fragments from all three isolates enhances the assumption that these bacteria produce polyketides. SWB005 was shown to produce metabolites with prominent antibacterial activity, including activity towards methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE)

    The Chemerin/ChemR23 System Does Not Affect the Pro-Inflammatory Response of Mouse and Human Macrophages Ex Vivo

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    Macrophages constitute a major component of innate immunity and play an essential role in defense mechanisms against external aggressions and in inflammatory responses. Chemerin, a chemoattractant protein, is generated in inflammatory conditions, and recruits cells expressing the G protein-coupled receptor ChemR23, including macrophages. Chemerin was initially expected to behave as a pro-inflammatory agent. However, recent data described more complex activities that are either pro- or anti-inflammatory, according to the disease model investigated. In the present study, peritoneal macrophages were generated from WT or ChemR23−/− mice, stimulated with lipopolyssaccharide in combination or not with IFN-γ and the production of pro- (TNF-α, IL-1β and IL-6) and anti-inflammatory (IL-10) cytokines was evaluated using qRT-PCR and ELISA. Human macrophages generated from peripheral blood monocytes were also tested in parallel. Peritoneal macrophages from WT mice, recruited by thioglycolate or polyacrylamide beads, functionally expressed ChemR23, as assessed by flow cytometry, binding and chemotaxis assays. However, chemerin had no effect on the strong upregulation of cytokine release by these cells upon stimulation by LPS or LPS/IFN-γ, whatever the concentration tested. Similar data were obtained with human macrophages. In conclusion, our results rule out the direct anti-inflammatory effect of chemerin on macrophages ex vivo, described previously in the literature, despite the expression of a functional ChemR23 receptor in these cells
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