RNA-mediated chromatin silencing is central to genome regulation in many organisms. However, how nascent non-coding transcripts regulate chromatin is poorly understood. Here, through analysis of ...Arabidopsis FLC, we show that resolution of a nascent-transcript-induced R-loop promotes chromatin silencing. Stabilization of an antisense-induced R-loop at the 3' end of FLC enables an RNA binding protein FCA, with its direct partner FY/WDR33 and other 3'-end processing factors, to polyadenylate the nascent antisense transcript. This clears the R-loop and recruits the chromatin modifiers demethylating H3K4me1. FCA immunoprecipitates with components of the m
A writer complex, and m
A modification affects dynamics of FCA nuclear condensates, and promotes FLC chromatin silencing. This mechanism also targets other loci in the Arabidopsis genome, and consistent with this fca and fy are hypersensitive to a DNA damage-inducing drug. These results show how modulation of R-loop stability by co-transcriptional RNA processing can trigger chromatin silencing.
Metal-free, base-free, biomimetic and chemoselective synthesis of 2,4,6-trisubstituted pyridines was developed under mild conditions for the first time. The heterogeneous biomimetic catalyst - ...recoverable Merrifield resin-supported quinone - was fully characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectrometry (XPS) and energy dispersive X-ray spectroscopy (EDX). This supported quinone catalyst exhibited excellent catalytic reactivity for chemoselective synthesis of 2,4,6-trisubstituted pyridines, providing an efficient and green method for the synthesis of pyridine derivatives under mild conditions. Mechanistic investigations were conducted to gain insights into the heterogeneous biomimetic catalyst as well as the resulting transformation. The successful capture of intermediates offered direct and clear evidence for the proposed mechanism.
Metal-free, base-free, biomimetic, and chemoselective synthesis of 2,4,6-trisubstituted pyridines was developed for the first time under mild conditions.
This paper proposes a data-driven affinely adjustable distributionally robust method for unit commitment considering uncertain load and renewable generation forecasting errors. The proposed ...formulation minimizes expected total operation costs, including the costs of generation, reserve, wind curtailment, and load shedding, while guaranteeing the system security. Without any presumption about the probability distribution of the uncertainties, the proposed method constructs an ambiguity set of distributions using historical data and immunizes the operation strategies against the worst case distribution in the ambiguity set. The more historical data is available, the smaller the ambiguity set is and the less conservative the solution is. The formulation is finally cast into a mixed integer linear programming whose scale remains unchanged as the amount of historical data increases. Numerical results and Monte Carlo simulations on the 118- and 1888-bus systems demonstrate the favorable features of the proposed method.
'Taishuu' has a crisp texture, abundant juice, and sweet flavor with hints of cantaloupe. The availability of mitochondrial genome data of Diospyros species is far from the known number of species.
...The sequencing data were assembled into a closed circular mitochondrial chromosome with a 421,308 bp length and a 45.79% GC content. The mitochondrial genome comprised 40 protein-coding, 24 tRNA, and three rRNA genes. The most common codons for arginine (Arg), proline (Pro), glycine (Gly), tryptophan (Trp), valine (Val), alanine (Ala), and leucine (Leu) were AGA, CCA, GGA, UGG, GUA, GCA, and CUA, respectively. The start codon for cox1 and nad4L protein-coding genes was ACG (ATG), whereas the remaining protein-coding genes started with ATG. There are four types of stop codons: CGA, TAA, TAG, and TGA, with TAA being the most frequently used stop codon (45.24%). In the D. kaki Thunb. 'Taishuu' mitochondrial genome, a total of 645 repeat sequences were identified, including 125 SSRs, 7 tandem repeats, and 513 dispersed repeats. Collinearity analysis revealed a close relationship between D. kaki Thunb. 'Taishuu' and Diospyros oleifera, with conserved homologous gene fragments shared among these species in large regions of the mitochondrial genome. The protein-coding genes ccmB and nad4L were observed to undergo positive selection. Analysis of homologous sequences between chloroplasts and mitochondria identified 28 homologous segments, with a total length of 24,075 bp, accounting for 5.71% of the mitochondrial genome. These homologous segments contain 8 annotated genes, including 6 tRNA genes and 2 protein-coding genes (rrn18 and ccmC). There are 23 homologous genes between chloroplasts and nuclei. Mitochondria, chloroplasts, and nuclei share two homologous genes, which are trnV-GAC and trnW-CCA.
In conclusion, a high-quality chromosome-level draft genome for D. kaki was generated in this study, which will contribute to further studies of major economic traits in the genus Diospyros.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cellulose is the most abundant renewable natural polymer on earth, but it does not conduct electricity, which limits its application expansion. The existing methods of making cellulose conductive are ...combined with another conductive material or high-temperature/high-pressure carbonization of the cellulose itself, while in the traditional method of sulfuric acid hydrolysis to extract nanocellulose, it is usually believed that a too high temperature will destroy cellulose and lead to experimental failure. Now, based on a new research perspective, by controlling the continuous reaction process and isolating oxygen, we directly extracted intrinsically conductive cellulose nanofiber (CNF) from biomass, where the confined range molecular chains of CNF were converted to highly graphitized carbon at only 90 °C and atmospheric pressure, while large-scale twisted graphene films can be synthesized bottom-up from CNFene suspensions, called CNFene (cellulose nanofiber–graphene). The conductivity of the best CNFene can be as high as 1.099 S/cm, and the generality of this synthetic route has been verified from multiple biomass cellulose sources. By comparing the conventional high-pressure hydrothermal and high-temperature pyrolysis methods, this study avoided the dangerous high-pressure environment and saved 86.16% in energy. These findings break through the conventional notion that nanocellulose cannot conduct electricity by itself and are expected to extend the application potential of pure nanocellulose to energy storage, catalysis, and sensing.
Azulene‐Embedded [n]Helicenes (n=5, 6 and 7) Duan, Chao; Zhang, Jianwei; Xiang, Junjun ...
Angewandte Chemie International Edition,
April 25, 2022, Letnik:
61, Številka:
18
Journal Article
Recenzirano
Azulene is a non‐benzenoid aromatic building block with unique chemical structure and physicochemical properties. By using the “bottom‐up” synthetic strategy, we synthesized three azulene‐embedded ...nhelicenes (nAzHs, n=5, 6 and 7), in which one terminal azulene subunit was fused with n‐2 benzene rings. P‐ and M‐enantiomers were observed in the packing diagrams of 5‐, and 6AzHs. However, P‐ and M‐7AzHs could be isolated by recrystallization of the racemic mixture. These nAzHs were endowed with new properties through the azulene moiety such as low‐lying first electric state (S1), small optical energy gap and anti‐Kasha emission. 6‐, and 7AzHs exhibit strong chiroptical responses with high absorption dissymmetry factor (gabs) maxima of about 0.02, which is among the highest |gabs| values of helicenes in the visible range. These azulene‐embedded nhelicenes contribute to the non‐benzenoid helicene library and allow the structure–property relationships to be better understood.
A straightforward “bottom‐up” approach has been used to synthesize azulene‐embedded pristine nhelicenes (n=5, 6 and 7) that show low‐lying first electric states, small optical energy gaps, and anti‐Kasha emissions. These azulene‐embedded nhelicenes contribute to the non‐benzenoid helicene library and allow structure–property relationships to be better understood.
•A facile route to prepare a CMF bio-adsorbent for the removal of heavy metal ions in water.•The CMF adsorbent has the advantages in biodegradability and solid-liquid separation.•The inner charges of ...CMF have a more significant contribution to the adsorption capacity.•It will provide a new strategy for the further modification and improvement of cellulose-based adsorbent.
In this work, we develop a facile route to prepare a cellulose-based adsorbent, namely carboxymethylated cellulose fiber (CMF), for the water purification. The as-prepared CMF bio-adsorbent was synthesized via a controllable carboxymethylation modification in the case of maintaining inherent fibrous framework. The CMF bio-adsorbent was applied to adsorb the heavy metal ions, such as Cu(II) and Ni(II), from aqueous solution. Results showed that the CMF adsorbent exhibited excellent adsorption capacity toward these ions and a higher selectivity for the Cu(II) removal based on surface complexation and electrostatic interaction mechanisms. Besides, the adsorption isotherm of Cu(II) fitted better with the Langmuir isotherm model. Moreover, the relationship between the charges and adsorption capacity of CMF to Cu(II) revealed that the enhanced adsorption capacity of CMF adsorbent can mainly attributed to its increased inner charges rather than surface charges, which can provide a new strategy for the further modification of cellulose-based adsorbent.
RNA N
-methyladenosine (m
A) modifications are essential in plants. Here, we show that transgenic expression of the human RNA demethylase FTO in rice caused a more than threefold increase in grain ...yield under greenhouse conditions. In field trials, transgenic expression of FTO in rice and potato caused ~50% increases in yield and biomass. We demonstrate that the presence of FTO stimulates root meristem cell proliferation and tiller bud formation and promotes photosynthetic efficiency and drought tolerance but has no effect on mature cell size, shoot meristem cell proliferation, root diameter, plant height or ploidy. FTO mediates substantial m
A demethylation (around 7% of demethylation in poly(A) RNA and around 35% decrease of m
A in non-ribosomal nuclear RNA) in plant RNA, inducing chromatin openness and transcriptional activation. Therefore, modulation of plant RNA m
A methylation is a promising strategy to dramatically improve plant growth and crop yield.
Iridium‐on‐phosphorus‐doped porous organic polymers (POP−Ir) were developed by anchoring simple iridium onto the skeleton of porous organic polymers through coordination bonds. This POP−Ir catalyst, ...which was thoroughly characterized by means of EDS, SEM, TEM, XRD, XPS, and FT‐IR, revealed excellent catalytic activity for the reaction of diphenyl phosphinamide with benzyl alcohols through borrowing hydrogen strategy and acceptorless dehydrogenation with wide functional group tolerance. Moreover, this POP−Ir catalyst could be simply recovered and reused for at least five times without a significant loss of activity, and revealed considerable application prospects. The mechanism was investigated to further understand this POP−Ir catalytic system and transformations. Overall, the POP−Ir catalytic system has shown high activity and reusability in the borrowing hydrogen reaction between diphenyl phosphinamides and benzyl alcohols.
Herein, we report an efficient and straightforward approach for the synthesis of
-alkylated aminoquinoline derivatives by recyclable Cd-containing coordination polymer-catalyzed reactions of ...aminoquinolines with primary alcohols
the borrowing hydrogen strategy. In this work, a new type of coordination polymer Cd(CIA)(phen)
(H
O)
was successfully designed and fabricated. The molecular structure was corroborated by single-crystal X-ray diffraction and fully characterized by PXRD, FT-IR, TGA, and XPS. Importantly, this polymer revealed high catalytic activity for the
-alkylation reaction of 2-aminoquinoline and 8-aminoquinoline with inexpensive and low-toxicity alcohols as alkylating agents in excellent yields up to 95%. Interestingly, the present synthetic protocol was successfully applied for the gram-level synthesis of several biologically active compounds. In addition, several control reactions were carried out to investigate the possible mechanisms of this transformation. Finally, recycling experiments indicated that the cadmium coordination polymer showed good recovery performance for borrowing hydrogen reactions.
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