Highlights • Simultaneity and temporal order judgment tasks assess temporal processing of stimuli. • The two tasks were compared in a blocked-design fMRI study with audiovisual pairs. • Both tasks ...activated the bilateral attentional fronto-parietal network. • Activation in left frontal, parietal and temporo-occipital regions was observed for temporal order judgments. • Simultaneity judgments did not reveal any additional activation.
Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. ...However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)
cytotoxic T cells and a CD8
T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.
The central role of translation in modulating gene activity has long been recognized, yet the systematic exploration of quantitative changes in translation at a genome-wide scale in response to a ...specific stimulus has only recently become technically feasible. Using the well-characterized signaling pathway of the phytohormone ethylene and plant-optimized genome-wide ribosome footprinting, we have uncovered a molecular mechanism linking this hormone’s perception to the activation of a gene-specific translational control mechanism. Characterization of one of the targets of this translation regulatory machinery, the ethylene signaling component EBF2, indicates that the signaling molecule EIN2 and the nonsense-mediated decay proteins UPFs play a central role in this ethylene-induced translational response. Furthermore, the 3′UTR of EBF2 is sufficient to confer translational regulation and required for the proper activation of ethylene responses. These findings represent a mechanistic paradigm of gene-specific regulation of translation in response to a key growth regulator.
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•Ribosome footprinting uncovers a role of translation in the ethylene response•The EBF2 3′UTR is sufficient to confer translational control•Regulation of EBF2 translation is required for proper ethylene responses•EBF2 translation control depends on functional EIN2 and UPFs, but not EIN3/EIL1
Ribosome footprinting unveils gene-specific regulation of translation by the hormone ethylene involving the 3′UTR of the transcript of a known negative regulator, as well as a key ethylene signaling protein and the components of the nonsense-mediated decay machinery.
Ethylene signaling in plants Binder, Brad M.
Journal of biological chemistry/The Journal of biological chemistry,
05/2020, Letnik:
295, Številka:
22
Journal Article
Recenzirano
Odprti dostop
Ethylene is a gaseous phytohormone and the first of this hormone class to be discovered. It is the simplest olefin gas and is biosynthesized by plants to regulate plant development, growth, and ...stress responses via a well-studied signaling pathway. One of the earliest reported responses to ethylene is the triple response. This response is common in eudicot seedlings grown in the dark and is characterized by reduced growth of the root and hypocotyl, an exaggerated apical hook, and a thickening of the hypocotyl. This proved a useful assay for genetic screens and enabled the identification of many components of the ethylene-signaling pathway. These components include a family of ethylene receptors in the membrane of the endoplasmic reticulum (ER); a protein kinase, called constitutive triple response 1 (CTR1); an ER-localized transmembrane protein of unknown biochemical activity, called ethylene-insensitive 2 (EIN2); and transcription factors such as EIN3, EIN3-like (EIL), and ethylene response factors (ERFs). These studies led to a linear model, according to which in the absence of ethylene, its cognate receptors signal to CTR1, which inhibits EIN2 and prevents downstream signaling. Ethylene acts as an inverse agonist by inhibiting its receptors, resulting in lower CTR1 activity, which releases EIN2 inhibition. EIN2 alters transcription and translation, leading to most ethylene responses. Although this canonical pathway is the predominant signaling cascade, alternative pathways also affect ethylene responses. This review summarizes our current understanding of ethylene signaling, including these alternative pathways, and discusses how ethylene signaling has been manipulated for agricultural and horticultural applications.
Perivascular spaces are important highways for fluid and solute transport in the brain enabling efficient waste clearance during sleep. However, the underlying mechanisms augmenting perivascular flow ...in sleep are unknown. Using two-photon imaging of naturally sleeping male mice we demonstrate sleep cycle-dependent vascular dynamics of pial arteries and penetrating arterioles: slow, large-amplitude oscillations in NREM sleep, a vasodilation in REM sleep, and a vasoconstriction upon awakening at the end of a sleep cycle and microarousals in NREM and intermediate sleep. These vascular dynamics are mirrored by changes in the size of the perivascular spaces of the penetrating arterioles: slow fluctuations in NREM sleep, reduction in REM sleep and an enlargement upon awakening after REM sleep and during microarousals in NREM and intermediate sleep. By biomechanical modeling we demonstrate that these sleep cycle-dependent perivascular dynamics likely enhance fluid flow and solute transport in perivascular spaces to levels comparable to cardiac pulsation-driven oscillations.
The individual roles of auxin and ethylene in controlling the growth and development of young seedlings have been well studied. In recent years, these two hormones have been shown to act ...synergistically to control specific growth and developmental processes, such as root elongation and root hair formation, as well as antagonistically in other processes, such as lateral root formation and hypocotyl elongation. This review examines the growth and developmental processes that are regulated by crosstalk between these two hormones and explores the mechanistic basis for the regulation of these processes. The emerging trend from these experiments is that ethylene modulates auxin synthesis, transport, and signaling with unique targets and responses in a range of tissues to fine-tune seedling growth and development.
Mutations in cell-free circulating DNA (cfDNA) have been studied for tracking disease relapse in colorectal cancer (CRC). This approach requires personalised assay design due to the lack of ...universally mutated genes. In contrast, early methylation alterations are restricted to defined genomic loci allowing comprehensive assay design for population studies. Our objective was to identify cancer-specific methylated biomarkers which could be measured longitudinally in cfDNA (liquid biopsy) to monitor therapeutic outcome in patients with metastatic CRC (mCRC).
Genome-wide methylation microarrays of CRC cell lines (n=149) identified five cancer-specific methylated loci (
,
,
,
). Digital PCR assays were employed to measure methylation of these genes in tumour tissue DNA (n=82) and cfDNA from patients with mCRC (n=182). Plasma longitudinal assessment was performed in a patient subset treated with chemotherapy or targeted therapy.
Methylation in at least one marker was detected in all tumour tissue samples and in 156 mCRC patient cfDNA samples (85.7%). Plasma marker prevalence was 71.4% for
, 68.5% for
, 69.7% for
, 69.1% for
and 65.1% for
. Dynamics of methylation markers was not affected by treatment type and correlated with objective tumour response and progression-free survival.
This five-gene methylation panel can be used to circumvent the absence of patient-specific mutations for monitoring tumour burden dynamics in liquid biopsy under different therapeutic regimens. This method might be proposed for assessing pharmacodynamics in clinical trials or when conventional imaging has limitations.
We investigate phonon induced electronic dynamics in the ground and excited states of the negatively charged silicon-vacancy ( ) centre in diamond. Optical transition line widths, transition ...wavelength and excited state lifetimes are measured for the temperature range 4 K-350 K. The ground state orbital relaxation rates are measured using time-resolved fluorescence techniques. A microscopic model of the thermal broadening in the excited and ground states of the centre is developed. A vibronic process involving single-phonon transitions is found to determine orbital relaxation rates for both the ground and the excited states at cryogenic temperatures. We discuss the implications of our findings for coherence of qubits in the ground states and propose methods to extend coherence times of qubits.
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