Three 20(S)-protopanaxatriol-type saponins, ginsenoside-Rg1 (1), notoginsenoside-R1 (2), and ginsenoside-Re (3), were transformed by the fungus Absidia coerulea (AS 3.3389). Compound 1 was converted ...into five metabolites, ginsenoside-Rh4 (4), 3β,2β,25-trihydroxydammar-(E)-20(22)-ene-6-O-β-d-glucopyranoside (5), 20(S)-ginsenoside-Rh1 (6), 20(R)-ginsenoside-Rh1 (7), and a mixture of 25-hydroxy-20(S)-ginsenoside-Rh1 and its C-20(R) epimer (8). Compound 2 was converted into 10 metabolites, 20(S)-notoginsenoside-R2 (9), 20(R)-notoginsenoside-R2 (10), 3β,12β,25-trihydroxydammar-(E)-20(22)-ene-6-O-β-d-xylopyranosyl-(1→2)-β-d-glucopyranoside (11), 3β,12β-dihydroxydammar-(E)-20(22),24-diene-6-O-β-d-xylopyranosyl-(1→2)-β-d-glucopyranoside (12), 3β,12β,20,25-tetrahydroxydammaran-6-O-β-d-xylopyranosyl-(1→2)-β-d-glucopyranoside (13), and compounds 4−8. Compound 3 was metabolized to 20(S)-ginsenoside-Rg2 (14), 20(R)-ginsenoside-Rg2 (15), 3β,12β,25-trihydroxydammar-(E)-20(22)-ene-6-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranoside (16), 3β,12β-dihydroxydammar-(E)-20(22),24-diene-6-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranoside (17), 3β,12β,20,25-tetrahydroxydammaran-6-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranoside (18), and compounds 4−8. The structures of five new metabolites, 10−13 and 16, were established by spectroscopic methods.
Single-cell transcriptomic assays have enabled the de novo reconstruction of lineage differentiation trajectories, along with the characterization of cellular heterogeneity and state transitions. ...Several methods have been developed for reconstructing developmental trajectories from single-cell transcriptomic data, but efforts on analyzing single-cell epigenomic data and on trajectory visualization remain limited. Here we present STREAM, an interactive pipeline capable of disentangling and visualizing complex branching trajectories from both single-cell transcriptomic and epigenomic data. We have tested STREAM on several synthetic and real datasets generated with different single-cell technologies. We further demonstrate its utility for understanding myoblast differentiation and disentangling known heterogeneity in hematopoiesis for different organisms. STREAM is an open-source software package.
Uveal melanomas are molecularly distinct from cutaneous melanomas and lack mutations in BRAF, NRAS, KIT, and NF1. Instead, they are characterized by activating mutations in GNAQ and GNA11, two highly ...homologous α subunits of Gαq/11 heterotrimeric G proteins, and in PLCB4 (phospholipase C β4), the downstream effector of Gαq signaling. We analyzed genomics data from 136 uveal melanoma samples and found a recurrent mutation in CYSLTR2 (cysteinyl leukotriene receptor 2) encoding a p.Leu129Gln substitution in 4 of 9 samples that lacked mutations in GNAQ, GNA11, and PLCB4 but in 0 of 127 samples that harbored mutations in these genes. The Leu129Gln CysLT2R mutant protein constitutively activates endogenous Gαq and is unresponsive to stimulation by leukotriene. Expression of Leu129Gln CysLT2R in melanocytes enforces expression of a melanocyte-lineage signature, drives phorbol ester-independent growth in vitro, and promotes tumorigenesis in vivo. Our findings implicate CYSLTR2 as a uveal melanoma oncogene and highlight the critical role of Gαq signaling in uveal melanoma pathogenesis.
Exposure to drugs of abuse produces robust transcriptional and epigenetic reorganization within brain reward circuits that outlives the direct effects of the drug and may contribute to addiction. DNA ...methylation is a covalent epigenetic modification that is altered following stimulant exposure and is critical for behavioral and physiological adaptations to drugs of abuse. Although activity-related loss of DNA methylation requires the Gadd45 (Growth arrest and DNA-damage-inducible) gene family, very little is known about how this family regulates activity within the nucleus accumbens or behavioral responses to drugs of abuse. Here, we combined genome-wide transcriptional profiling, pharmacological manipulations, electrophysiological measurements, and CRISPR tools with traditional knockout and behavioral approaches in rodent model systems to dissect the role of Gadd45b in dopamine-dependent epigenetic regulation and cocaine reward. We show that acute cocaine administration induces rapid upregulation of Gadd45b mRNA in the rat nucleus accumbens, and that knockout or site-specific CRISPR/Cas9 gene knockdown of Gadd45b blocks cocaine conditioned place preference. In vitro, dopamine treatment in primary striatal neurons increases Gadd45b mRNA expression through a dopamine receptor type 1 (DRD1)-dependent mechanism. Moreover, shRNA-induced Gadd45b knockdown decreases expression of genes involved in psychostimulant addiction, blocks induction of immediate early genes by DRD1 stimulation, and prevents DRD1-mediated changes in DNA methylation. Finally, we demonstrate that Gadd45b knockdown decreases striatal neuron action potential burst duration in vitro, without altering other electrophysiological characteristics. These results suggest that striatal Gadd45b functions as a dopamine-induced gene that is necessary for cocaine reward memory and DRD1-mediated transcriptional activity.
ABSTRACT
WRKY proteins form a large family of plant transcription factors implicated in the modulation of numerous biological processes, such as growth, development and responses to various ...environmental stresses. However, the roles of the majority WRKY family members, especially in non‐model plants, remain poorly understood. We identified CaWRKY40 from pepper. Transient expression in onion epidermal cells showed that CaWRKY40 can be targeted to nuclei and activates expression of a W‐box‐containing reporter gene. CaWRKY40 transcripts are induced in pepper by Ralstonia solanacearum and heat shock. To assess roles of CaWRKY40 in plant stress responses we performed gain‐ and loss‐of‐function experiments. Overexpression of CaWRKY40 enhanced resistance to R. solanacearum and tolerance to heat shock in tobacco. In contrast, silencing of CaWRKY40 enhanced susceptibility to R. solanacearum and impaired thermotolerance in pepper. Consistent with its role in multiple stress responses, we found CaWRKY40 transcripts to be induced by signalling mechanisms mediated by the stress hormones salicylic acid (SA), jasmonic acid (JA) and ethylene (ET). Overexpression of CaWRKY40 in tobacco modified the expression of hypersensitive response (HR)‐associated and pathogenesis‐related genes. Collectively, our results suggest that CaWRKY40 orthologs are regulated by SA, JA and ET signalling and coordinate responses to R. solanacearum attacks and heat stress in pepper and tobacco.
Using reverse genetic approaches we show that CaWRKY40 promotes immunity against the bacterial pathogen Ralstonia solanacearum and tolerance against heat stress in pepper. Our findings are novel, because biological roles of WRKY transcription factors from Solanaceae have so far only been peripherally described. In addition, we are providing evidence for a WRKY‐dependent regulatory mechanism that simultaneously promotes resistance against pathogens and heat‐stress. This new WRKY function is unique and likely constitutes an important adaptation of pepper to conditions of high temperatures associated with enhanced pathogen pressure.
Sodium manganese oxide octahedral molecular sieves with a 2 × 4 tunnel structure (Na−2 × 4) have been hydrothermally synthesized from Na−birnessite materials at low temperatures and pressures. The ...synthetic template materials, the pH value of the medium, and the autoclaved temperature are critical in the synthesis. Sodium salts, such as NaCl, NaNO3, and Na2SO4, are good templates for Na−2 × 4. In strong basic solution or below 160 °C, Na−birnessite does not transform to the Na−2 × 4 structure. TEM images show the synthesized Na−2 × 4 is made up of thin slablike single crystals elongated along the b axis. The formula of Na−2 × 4 can be written as Na0.33M M O2·xH2O, and it is monoclinic with space group C2/m. The unit cell parameters (a, b, c, and β) for Na−2 × 4 are 14.434(5) Å, 2.849(7) Å, 23.976(6) Å, and 98.18°, respectively. These data for Na−2 × 4 are slightly different from the data for Rb−2 × 4 synthesized under high pressure and high temperature, which were reported by Rziha et al. (Eur. J. Miner. 1996, 8, 1155−1161). The surface area of Na−2 × 4 is about 57 m2/g. Na−2 × 4 materials are thermally stable up to 450 °C as indicated by TGA and TPD data.
Genetic and pharmacological
studies have defined a role for the melanocortin-4 receptor (Mc4r) in the
regulation of energy homeostasis. The physiological function of Mc3r, a melanocortin
receptor ...expressed at high levels in the hypothalamus, has
remained unknown. We evaluated the potential role of Mc3r in energy homeostasis
by studying Mc3r-deficient (Mc3r−/−) mice
and compared the functions of Mc3r and Mc4r in mice deficient
for both genes. The 4-6-month Mc3r−/−
mice have increased fat mass, reduced lean mass and higher feed efficiency
than wild-type littermates, despite being hypophagic and maintaining normal
metabolic rates. (Feed efficiency is the ratio of weight gain to food intake.)
Consistent with increased fat mass, Mc3r−/−
mice are hyperleptinaemic and male Mc3r−/−
mice develop mild hyperinsulinaemia. Mc3r−/−
mice did not have significantly altered corticosterone or total thyroxine
(T4) levels. Mice lacking both Mc3r and Mc4r become significantly
heavier than Mc4r−/− mice. We conclude that
Mc3r and Mc4r serve non-redundant roles in the regulation of energy homeostasis.
In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations ...with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazônia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.
Despite the fact that phase-change materials are widely used for data storage, no consensus exists on the unique mechanism of their ultrafast phase change and its accompanied large and rapid optical ...change. By using the pump-probe observation method combining a femtosecond optical laser and an x-ray free-electron laser, we substantiate experimentally that, in both GeTe and Ge_{2}Sb_{2}Te_{5} crystals, rattling motion of mainly Ge atoms takes place with keeping the off-center position just after femtosecond-optical-laser irradiation, which eventually leads to a higher symmetry or disordered state. This very initial rattling motion in the undistorted lattice can be related to instantaneous optical change due to the loss of resonant bonding that characterizes GeTe-based phase change materials. Based on the amorphous structure derived by first-principles molecular dynamics simulation, we infer a plausible ultrafast amorphization mechanism via nonmelting.
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