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The rising rate of antimicrobial resistance continues to threaten global public health. Further hastening antimicrobial resistance is the lack of new antibiotics against new targets. The bacterial enzyme, 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), is thought to play important roles in central metabolism, including processes required for pathogen adaptation to fluctuating host environments. Thus, impairing DXPS function represents a possible new antibacterial strategy. We previously investigated a DXPS-dependent metabolic adaptation as a potential target in uropathogenic Escherichia coli (UPEC) associated with urinary tract infection (UTI), using the DXPS-selective inhibitor butyl acetylphosphonate (BAP). However, investigations of DXPS inhibitors in vivo have not been conducted. The goal of the present study is to advance DXPS inhibitors as in vivo probes and assess the potential of inhibiting DXPS as a strategy to prevent UTI in vivo. We show that BAP was well-tolerated at high doses in mice and displayed a favorable pharmacokinetic profile for studies in a mouse model of UTI. Further, an alkyl acetylphosphonate prodrug (homopropargyl acetylphosphonate, pro-hpAP) was significantly more potent against UPEC in urine culture and exhibited good exposure in the urinary tract after systemic dosing. Prophylactic treatment with either BAP or pro-hpAP led to a partial protective effect against UTI, with the prodrug displaying improved efficacy compared to BAP. Overall, our results highlight the potential for DXPS inhibitors as in vivo probes and establish preliminary evidence that inhibiting DXPS impairs UPEC colonization in a mouse model of UTI.IMPORTANCENew antibiotics against new targets are needed to prevent an antimicrobial resistance crisis. Unfortunately, antibiotic discovery has slowed, and many newly FDA-approved antibiotics do not inhibit new targets. Alkyl acetylphosphonates (alkyl APs), which inhibit the enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS), represent a new possible class of compounds as there are no FDA-approved DXPS inhibitors. To our knowledge, this is the first study demonstrating the in vivo safety, pharmacokinetics, and efficacy of alkyl APs in a urinary tract infection mouse model.
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Acetaldehído/análogos & derivados , Antiinfecciosos , Infecciones por Escherichia coli , Pentosafosfatos , Profármacos , Infecciones Urinarias , Escherichia coli Uropatógena , Animales , Ratones , Infecciones Urinarias/tratamiento farmacológico , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antibacterianos/metabolismo , Antiinfecciosos/farmacología , Infecciones por Escherichia coli/tratamiento farmacológico , Escherichia coli Uropatógena/metabolismoRESUMEN
Arbuscular mycorrhizal fungi (AMF) are prominent root symbionts that can carry thousands of nuclei deriving from two parental strains in a large syncytium. These co-existing genomes can also vary in abundance with changing environmental conditions. Here we assemble the nuclear genomes of all four publicly available AMF heterokaryons using PacBio high-fidelity and Hi-C sequencing. We find that the two co-existing genomes of these strains are phylogenetically related but differ in structure, content and epigenetics. We confirm that AMF heterokaryon genomes vary in relative abundance across conditions and show this can lead to nucleus-specific differences in expression during interactions with plants. Population analyses also reveal signatures of genetic exchange indicative of past events of sexual reproduction in these strains. This work uncovers the origin and contribution of two nuclear genomes in AMF heterokaryons and opens avenues for the improvement and environmental application of these strains.
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Micorrizas , Micorrizas/genética , PlantasRESUMEN
Pathogenic bacteria possess a remarkable ability to adapt to fluctuating host environments and cause infection. Disturbing bacterial central metabolism through inhibition of 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) has the potential to hinder bacterial adaptation, representing a new antibacterial strategy. DXPS functions at a critical metabolic branchpoint to produce the metabolite DXP, a precursor to pyridoxal-5-phosphate (PLP), thiamin diphosphate (ThDP) and isoprenoids presumed essential for metabolic adaptation in nutrient-limited host environments. However, specific roles of DXPS in bacterial adaptations that rely on vitamins or isoprenoids have not been studied. Here we investigate DXPS function in an adaptation of uropathogenic E. coli (UPEC) to d-serine (d-Ser), a bacteriostatic host metabolite that is present at high concentrations in the urinary tract. UPEC adapt to d-Ser by producing a PLP-dependent deaminase, DsdA, that converts d-Ser to pyruvate, pointing to a role for DXPS-dependent PLP synthesis in this adaptation. Using a DXPS-selective probe, butyl acetylphosphonate (BAP), and leveraging the toxic effects of d-Ser, we reveal a link between DXPS activity and d-Ser catabolism. We find that UPEC are sensitized to d-Ser and produce sustained higher levels of DsdA to catabolize d-Ser in the presence of BAP. In addition, BAP activity in the presence of d-Ser is suppressed by ß-alanine, the product of aspartate decarboxylase PanD targeted by d-Ser. This BAP-dependent sensitivity to d-Ser marks a metabolic vulnerability that can be exploited to design combination therapies. As a starting point, we show that combining inhibitors of DXPS and CoA biosynthesis displays synergy against UPEC grown in urine where there is increased dependence on the TCA cycle and gluconeogenesis from amino acids. Thus, this study provides the first evidence for a DXPS-dependent metabolic adaptation in a bacterial pathogen and demonstrates how this might be leveraged for development of antibacterial strategies against clinically relevant pathogens.
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This study aimed to gain a deeper understanding of spiritual change processes by conducting an empirical investigation of clinically meaningful events occurring within the context of a Christian-Integrated Psychotherapy Framework. The discovery phase of task analysis was used to build a rational-empirical model that explicated how clients developed stronger attachments to their God images. A rational model was specified, and five cases were selected for further analysis from a pool of 27 client-participants and 423 video-recorded psychotherapy sessions. Clinical observations and the coding of in-session measures were used to select resolved and unresolved cases, which were then contrasted to create a 10-step rational-empirical model. In this model, clients initially presented with intense feelings of shame, guilt, or helplessness but concluded with heightened levels of love and joy. Clients who reached this resolution all underwent an experience whereby their God images became dynamic, alive, intimate, and authentic. Results are discussed, and implications for the existence of an in vivo God image and corrective emotional spiritual experiences are introduced. Specifically, corrective emotional spiritual experiences appear to have influenced clients to transition from being insecurely attached to more securely attached to their in vivo God images. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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Relaciones Profesional-Paciente , Psicoterapia , Emociones , Humanos , Psicoterapia/métodosRESUMEN
Chromosome folding links genome structure with gene function by generating distinct nuclear compartments and topologically associating domains. In mammals, these undergo preferential interactions and regulate gene expression. However, their role in fungal genome biology is unclear. Here, we combine Nanopore (ONT) sequencing with chromatin conformation capture sequencing (Hi-C) to reveal chromosome and epigenetic diversity in a group of obligate plant symbionts: the arbuscular mycorrhizal fungi (AMF). We find that five phylogenetically distinct strains of the model AMF Rhizophagus irregularis carry 33 chromosomes with substantial within-species variability in size, as well as in gene and repeat content. Strain-specific Hi-C contact maps reveal a 'checkerboard' pattern that underline two dominant euchromatin (A) and heterochromatin (B) compartments. Each compartment differs in the level of gene transcription, regulation of candidate effectors and methylation frequencies. The A-compartment is more gene-dense and contains most core genes, while the B-compartment is more repeat-rich and has higher rates of chromosomal rearrangement. While the B-compartment is transcriptionally repressed, it has significantly more secreted proteins and in planta upregulated candidate effectors, suggesting a possible host-induced change in chromosome conformation. Overall, this study provides a fine-scale view into the genome biology and evolution of model plant symbionts, and opens avenues to study the epigenetic mechanisms that modify chromosome folding during host-microbe interactions.
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Glomeromycota , Micorrizas , Hongos , Genoma Fúngico , Glomeromycota/genética , Glomeromycota/metabolismo , Micorrizas/fisiología , Plantas/genéticaRESUMEN
Background: Glutamine synthetase (GS) is the only enzyme known to synthesize significant amounts of glutamine in mammals, and loss of GS in the hippocampus has been implicated in the pathophysiology of medication refractory mesial temporal lobe epilepsy (MTLE). Moreover, loss-of-function mutations of the GS gene causes severe epileptic encephalopathy, and supplementation with glutamine has been shown to normalize EEG and possibly improve the outcome in these patients. Here we examined whether oral glutamine supplementation is an effective treatment for MTLE by assessing the frequency and severity of seizures after supplementation in a translationally relevant model of the disease.Methods: Male Sprague Dawley rats (380-400â g) were allowed to drink unlimited amounts of glutamine in water (3.6% w/v; n = 8) or pure water (n = 8) for several weeks. Ten days after the start of glutamine supplementation, GS was chronically inhibited in the hippocampus to induce MTLE. Continuous video-intracranial EEG was collected for 21 days to determine the frequency and severity of seizures.Results: While there was no change in seizure frequency between the groups, the proportion of convulsive seizures was significantly higher in glutamine treated animals during the first three days of GS inhibition.Conclusion: The results suggest that oral glutamine supplementation transiently increases seizure severity in the initial stages of an epilepsy model, indicating a potential role of the amino acid in seizure propagation and epileptogenesis.
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Epilepsia del Lóbulo Temporal/fisiopatología , Glutamina/administración & dosificación , Convulsiones/inducido químicamente , Índice de Severidad de la Enfermedad , Animales , Suplementos Dietéticos , Modelos Animales de Enfermedad , Epilepsia del Lóbulo Temporal/etiología , Glutamato-Amoníaco Ligasa/antagonistas & inhibidores , Glutamato-Amoníaco Ligasa/metabolismo , Hipocampo/enzimología , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
Arbuscular mycorrhizal fungi (AMF) (subphylum Glomeromycotina)1 are among the most prominent symbionts and form the Arbuscular Mycorrhizal symbiosis (AMS) with over 70% of known land plants.2,3 AMS allows plants to efficiently acquire poorly soluble soil nutrients4 and AMF to receive photosynthetically fixed carbohydrates. This plant-fungus symbiosis dates back more than 400 million years5 and is thought to be one of the key innovations that allowed the colonization of lands by plants.6 Genomic and genetic analyses of diverse plant species started to reveal the molecular mechanisms that allowed the evolution of this symbiosis on the host side, but how and when AMS abilities emerged in AMF remain elusive. Comparative phylogenomics could be used to understand the evolution of AMS.7,8 However, the availability of genome data covering basal AMF phylogenetic nodes (Archaeosporales, Paraglomerales) is presently based on fragmentary protein coding datasets.9Geosiphon pyriformis (Archaeosporales) is the only fungus known to produce endosymbiosis with nitrogen-fixing cyanobacteria (Nostoc punctiforme) presumably representing the ancestral AMF state.10-12 Unlike other AMF, it forms long fungal cells ("bladders") that enclose cyanobacteria. Once in the bladder, the cyanobacteria are photosynthetically active and fix nitrogen, receiving inorganic nutrients and water from the fungus. Arguably, G. pyriformis represents an ideal candidate to investigate the origin of AMS and the emergence of a unique endosymbiosis. Here, we aimed to advance knowledge in these questions by sequencing the genome of G. pyriformis, using a re-discovered isolate.
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Hongos/genética , Genoma Fúngico , Micorrizas , Plantas , Cianobacterias , Micorrizas/genética , Fijación del Nitrógeno , Filogenia , Plantas/microbiología , Simbiosis/genéticaRESUMEN
Evidence for the existence of dikaryote-like strains, low nuclear sequence diversity and inter-nuclear recombination in arbuscular mycorrhizal fungi has been recently reported based on single nucleus sequencing data. Here, we aimed to support evidence of inter-nuclear recombination using an approach that filters SNP calls more conservatively, keeping only positions that are exclusively single copy and homozygous, and with at least five reads supporting a given SNP. This methodology recovers hundreds of putative inter-nucleus recombination events across publicly available sequence data from individual nuclei. Challenges related to the acquisition and analysis of sequence data from individual nuclei are highlighted and discussed, and ways to address these issues in future studies are presented.
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Arthritis, an inflammatory condition that causes pain and cartilage destruction in joints, affects over 54.4 million people in the US alone. Here, for the first time, we demonstrated the emerging role of neural EGFL like 1 (NELL-1) in arthritis pathogenesis by showing that Nell-1-haploinsufficient (Nell-1+/6R) mice had accelerated and aggravated osteoarthritis (OA) progression with elevated inflammatory markers in both spontaneous primary OA and chemical-induced secondary OA models. In the chemical-induced OA model, intra-articular injection of interleukin (IL)1ß induced more severe inflammation and cartilage degradation in the knee joints of Nell-1+/6R mice than in wildtype animals. Mechanistically, in addition to its pro-chondrogenic potency, NELL-1 also effectively suppressed the expression of inflammatory cytokines and their downstream cartilage catabolic enzymes by upregulating runt-related transcription factor (RUNX)1 in mouse and human articular cartilage chondrocytes. Notably, NELL-1 significantly reduced IL1ß-stimulated inflammation and damage to articular cartilage in vivo. In particular, NELL-1 administration markedly reduced the symptoms of antalgic gait observed in IL1ß-challenged Nell-1+/6R mice. Therefore, NELL-1 is a promising pro-chondrogenic, anti-inflammatory dual-functional disease-modifying osteoarthritis drug (DMOAD) candidate for preventing and suppressing arthritis-related cartilage damage.
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Proteínas de Unión al Calcio/genética , Cartílago Articular , Osteoartritis , Preparaciones Farmacéuticas , Animales , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Condrocitos , Condrogénesis , Interleucina-1beta/farmacología , Ratones , Osteoartritis/tratamiento farmacológicoRESUMEN
Drawing from the existing literature on minority stress and stigma, this article highlights challenges - psychological, social, and interpersonal - confronting transgender and gender nonconforming (TGNC) individuals in relation to their gender identity and expression. TGNC individuals are at risk for poor health due to societal stigma and stressors they face as a gender minority group. Further, TGNC individuals may experience stigma in different shapes and forms; specifically, stigma may occur as enacted, felt, internalized, and anticipated stigma. In maintaining an identity that is socially devalued but often invisible to others, TGNC individuals confront additional challenges in negotiating the risks and benefits of disclosing their stigmatized identity. Affirmative group therapy is proposed as a strength-based and social justice-oriented approach for demarginalizing TGNC individuals' stigmatized identity. Group therapists are called on to address how forms of stigma impact TGNC individuals within and outside of the group, provide validation and space for practicing disclosure, highlight their strengths and resilience, and serve as social justice advocates.
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Despite the inherent value and effectiveness of group therapy, group therapists often face language and cultural barriers in facilitating groups for immigrants and, in particular, forced migrants. Without adequately addressing these barriers, group therapists are unlikely to deliver culturally responsive and clinically effective treatments. In this article, modes of interpretation and roles of interpreters in mental health care are first discussed. Next, we highlight clinical, cultural, and ethical challenges of incorporating interpreters in group therapy, with special attention to issues in therapy groups for forced migrants. Opportunities and suggestions for maximizing the value of interpreters in group therapy are offered.
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BACKGROUND: Up to 40% of patients with epilepsy experience seizures despite treatment with antiepileptic drugs; however, branched-chain amino acid (BCAA) supplementation has shown promise in treating refractory epilepsy. OBJECTIVES: The purpose of this systematic review was to evaluate all published studies that investigated the effects of BCAAs on seizures, emphasizing therapeutic efficacy and possible underlying mechanisms. METHODS: On 31 January, 2017, the following databases were searched for relevant studies: MEDLINE (OvidSP), EMBASE (OvidSP), Scopus (Elsevier), the Cochrane Library, and the unindexed material in PubMed (National Library of Medicine/National Institutes of Health). The searches were repeated in all databases on 18 February, 2019. We only included full-length preclinical and clinical studies that were published in the English language that examined the effects of BCAA administration on seizures. RESULTS: Eleven of 2045 studies met our inclusion criteria: ten studies were conducted in animal models and one study in human subjects. Seven seizure models were investigated: the strychnine (one study), pentylenetetrazole (two studies), flurothyl (one study), picrotoxin (two studies), genetic absence epilepsy in rats (one study), kainic acid (two studies), and methionine sulfoximine (one study) paradigms. Three studies investigated the effect of a BCAA mixture whereas the other studies explored the effects of individual BCAAs on seizures. In most animal models and in humans, BCAAs had potent anti-seizure effects. However, in the methionine sulfoximine model, long-term BCAA supplementation worsened seizure propagation and caused neuron loss, and in the genetic absence epilepsy in rats model, BCAAs exhibited pro-seizure effects. CONCLUSIONS: The contradictory effects of BCAAs on seizure activity likely reflect differences in the complex mechanisms that underlie seizure disorders. Some of these mechanisms are likely mediated by BCAA's effects on glucose, glutamate, glutamine, and ammonia metabolism, activation of the mechanistic target of rapamycin signaling pathway, and their effects on aromatic amino acid transport and neurotransmitter synthesis. We propose that a better understanding of mechanisms by which BCAAs affect seizures and neuronal viability is needed to advance the field of BCAA supplementation in epilepsy.
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Aminoácidos de Cadena Ramificada/farmacología , Aminoácidos de Cadena Ramificada/uso terapéutico , Anticonvulsivantes/farmacología , Anticonvulsivantes/uso terapéutico , Convulsiones/tratamiento farmacológico , Animales , HumanosRESUMEN
Glomeromycotina is a lineage of early diverging fungi that establish arbuscular mycorrhizal (AM) symbiosis with land plants. Despite their major ecological role, the genetic basis of their obligate mutualism remains largely unknown, hindering our understanding of their evolution and biology. We compared the genomes of Glomerales (Rhizophagus irregularis, Rhizophagus diaphanus, Rhizophagus cerebriforme) and Diversisporales (Gigaspora rosea) species, together with those of saprotrophic Mucoromycota, to identify gene families and processes associated with these lineages and to understand the molecular underpinning of their symbiotic lifestyle. Genomic features in Glomeromycotina appear to be very similar with a very high content in transposons and protein-coding genes, extensive duplications of protein kinase genes, and loss of genes coding for lignocellulose degradation, thiamin biosynthesis and cytosolic fatty acid synthase. Most symbiosis-related genes in R. irregularis and G. rosea are specific to Glomeromycotina. We also confirmed that the present species have a homokaryotic genome organisation. The high interspecific diversity of Glomeromycotina gene repertoires, affecting all known protein domains, as well as symbiosis-related orphan genes, may explain the known adaptation of Glomeromycotina to a wide range of environmental settings. Our findings contribute to an increasingly detailed portrait of genomic features defining the biology of AM fungi.
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Genoma Fúngico , Genómica , Glomeromycota/genética , Secuencia Conservada , Elementos Transponibles de ADN/genética , Genes Fúngicos , Lignina/metabolismo , Familia de Multigenes , Filogenia , Polisacáridos/metabolismo , Reproducción , Simbiosis/genética , Transcripción Genética , Regulación hacia Arriba/genéticaRESUMEN
Contactin-associated protein-like 4 (Cntnap4) is a member of the neurexin superfamily of transmembrane molecules that have critical functions in neuronal cell communication. Cntnap4 knockout mice display decreased presynaptic gamma-aminobutyric acid (GABA) and increased dopamine release that is associated with severe, highly penetrant, repetitive, and perseverative movements commonly found in human autism spectrum disorder patients. However, no known function of Cntnap4 has been revealed besides the nervous system. Meanwhile, secretory protein neural EGFL-like 1 (Nell-1) is known to exert potent osteogenic effects in multiple small and large animal models without the off-target effects commonly found with bone morphogenetic protein 2. In this study, while searching for a Nell-1-specific cell surface receptor during osteogenesis, we identified and validated a ligand/receptor-like interaction between Nell-1 and Cntnap4 by demonstrating: 1) Nell-1 and Cntnap4 colocalization on the surface of osteogenic-committed cells; 2) high-affinity interaction between Nell-1 and Cntnap4; 3) abrogation of Nell-1-responsive Wnt and MAPK signaling transduction, as well as osteogenic effects, via Cntnap4 knockdown; and 4) replication of calvarial cleidocranial dysplasias-like defects observed in Nell-1-deficient mice in Wnt1-Cre-mediated Cntnap4-knockout transgenic mice. In aggregate, these findings indicate that Cntnap4 plays a critical role in Nell-1-responsive osteogenesis. Further, this is the first functional annotation for Cntnap4 in the musculoskeletal system. Intriguingly, Nell-1 and Cntnap4 also colocalize on the surface of human hippocampal interneurons, implicating Nell-1 as a potential novel ligand for Cntnap4 in the nervous system. This unexpected characterization of the ligand/receptor-like interaction between Nell-1 and Cntnap4 indicates a novel biological functional axis for Nell-1 and Cntnap4 in osteogenesis and, potentially, in neural development and function. © 2018 American Society for Bone and Mineral Research.
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Proteínas de Unión al Calcio/metabolismo , Glicoproteínas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Osteogénesis , Secuencia de Aminoácidos , Animales , Animales Recién Nacidos , Bacteriófago T7/metabolismo , Médula Ósea/metabolismo , Línea Celular , Linaje de la Célula , Membrana Celular/metabolismo , Eliminación de Gen , Humanos , Integrasas/metabolismo , Proteínas de la Membrana/química , Ratones Endogámicos C57BL , Ratones Noqueados , Modelos Biológicos , Proteínas del Tejido Nervioso/química , Unión Proteica , Dominios Proteicos , Transducción de Señal , Cráneo/metabolismoRESUMEN
Arbuscular mycorrhizal fungi (AMF) are known to improve plant fitness through the establishment of mycorrhizal symbioses. Genetic and phenotypic variations among closely related AMF isolates can significantly affect plant growth, but the genomic changes underlying this variability are unclear. To address this issue, we improved the genome assembly and gene annotation of the model strain Rhizophagus irregularis DAOM197198, and compared its gene content with five isolates of R. irregularis sampled in the same field. All isolates harbor striking genome variations, with large numbers of isolate-specific genes, gene family expansions, and evidence of interisolate genetic exchange. The observed variability affects all gene ontology terms and PFAM protein domains, as well as putative mycorrhiza-induced small secreted effector-like proteins and other symbiosis differentially expressed genes. High variability is also found in active transposable elements. Overall, these findings indicate a substantial divergence in the functioning capacity of isolates harvested from the same field, and thus their genetic potential for adaptation to biotic and abiotic changes. Our data also provide a first glimpse into the genome diversity that resides within natural populations of these symbionts, and open avenues for future analyses of plant-AMF interactions that link AMF genome variation with plant phenotype and fitness.
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Variación Genética , Genoma Fúngico , Glomeromycota/genética , Modelos Biológicos , Micorrizas/genética , Simbiosis/genética , Adaptación Fisiológica/genética , Elementos Transponibles de ADN/genética , Proteínas Fúngicas/química , Genes Fúngicos , Glomeromycota/aislamiento & purificación , Anotación de Secuencia Molecular , Filogenia , Dominios Proteicos , Especificidad de la EspecieRESUMEN
Arbuscular mycorrhizal fungi (AMF) are a group of soil microorganisms that establish symbioses with the vast majority of land plants. To date, generation of AMF coding information has been limited to model genera that grow well axenically; Rhizoglomus and Gigaspora. Meanwhile, data on the functional gene repertoire of most AMF families is non-existent. Here, we provide primary large-scale transcriptome data from eight poorly studied AMF species (Acaulospora morrowiae, Diversispora versiforme, Scutellospora calospora, Racocetra castanea, Paraglomus brasilianum, Ambispora leptoticha, Claroideoglomus claroideum and Funneliformis mosseae) using ultra-low input ribonucleic acid (RNA)-seq approaches. Our analyses reveals that quiescent spores of many AMF species harbour a diverse functional diversity and solidify known evolutionary relationships within the group. Our findings demonstrate that RNA-seq data obtained from low-input RNA are reliable in comparison to conventional RNA-seq experiments. Thus, our methodology can potentially be used to deepen our understanding of fungal microbial function and phylogeny using minute amounts of RNA material.
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Perfilación de la Expresión Génica , Glomeromycota/genética , Filogenia , Glomeromycota/metabolismo , Micorrizas/genética , Micorrizas/metabolismo , Análisis de Secuencia de ARN , Microbiología del Suelo , Esporas Fúngicas/genética , TranscriptomaRESUMEN
The study assessed the clinical utility of an invented spelling tool and determined whether invented spelling with linguistic manipulation at segmental and supra-segmental levels can be used to better identify reading difficulties. We conducted linguistic manipulation by using real and nonreal words, incorporating word stress, alternating the order of consonants and vowels, and alternating the number of syllables. We recruited 60 third-grade students, of which half were typical readers and half were poor readers. The invented spelling task consistently differentiated those with reading difficulties from typical readers. It explained unique variance in conventional spelling, but not in word reading. Word stress explained unique variance in both word reading and conventional spelling, highlighting the importance of addressing phonological awareness at the supra-segmental level. Poor readers had poorer performance when spelling both real and nonreal words and demonstrated substantial difficulty in detecting word stress. Poor readers struggled with spelling words with double consonants at the beginning and ending of words, and performed worse on spelling two- and three-syllable words than typical readers. Practical implications for early identification and instruction are discussed.
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Concienciación , Lectura , Vocabulario , Niño , Femenino , Humanos , Lenguaje , Pruebas del Lenguaje , Masculino , FonéticaRESUMEN
The pro-chondrogenic function of runt-related transcription factor 2 (Runx2) was previously considered to be dependent on direct binding with the promoter of Indian hedgehog (Ihh)-the major regulator of chondrocyte differentiation, proliferation, and maturation. The authors' previous studies identified neural EGFL like 1 (Nell-1) as a Runx2-responsive growth factor for chondrogenic differentiation and maturation. In this study, it was further revealed that the pro-chondrogenic activities of Nell-1 also rely on Ihh signaling, by showing: i) Nell-1 significantly elevated Ihh signal transduction; ii) Nell-1 deficiency markedly reduced Ihh activation in chondrocytes; and iii) Nell-1-stimulated chondrogenesis was significantly reduced by the specific hedgehog inhibitor cyclopamine. Importantly, the authors demonstrated that Nell-1-responsive Ihh signaling and chondrogenic differentiation extended to Runx2-/- models in vitro and in vivo. In Runx2-/- chondrocytes, Nell-1 stimulated the expression and signal transduction of Runx3, another transcription factor required for complete chondrogenic differentiation and maturation. Furthermore, knocking down Runx3 in Runx2-/- chondrocytes abolished Nell-1's stimulation of Ihh-associated molecule expression, which validates Runx3 as a major mediator of Nell-1-stimulated Ihh activation. For the first time, the Runx2âNell-1âRunx3âIhh signaling cascade during chondrogenic differentiation and maturation has been identified as an alternative, but critical, pathway for Runx2 to function as a pro-chondrogenic molecule via Nell-1.