The placenta is crucial for a successful pregnancy and the health of both the fetus and the pregnant woman. However, how the human trophoblast lineage is regulated, including the categorization of ...the placental cell subtypes is poorly understood. Here we performed single-cell RNA sequencing (RNA-seq) on sorted placental cells from first- and second-trimester human placentas. New subtypes of cells of the known cytotrophoblast cells (CTBs), extravillous trophoblast cells (EVTs), Hofbauer cells, and mesenchymal stromal cells were identified and cell-type-specific gene signatures were defined. Functionally, this study revealed many previously unknown functions of the human placenta. Notably, 102 polypeptide hormone genes were found to be expressed by various subtypes of placental cells, which suggests a complex and significant role of these hormones in regulating fetal growth and adaptations of maternal physiology to pregnancy. These results document human placental trophoblast differentiation at single-cell resolution and thus advance our understanding of human placentation during the early stage of pregnancy.
Arabidopsis mutants produced by constitutive overexpression of the CRISPR/Cas9 genome editing system are usually mosaics in the T1 generation. In this study, we used egg cell-specific promoters to ...drive the expression of Cas9 and obtained non-mosaic T1 mutants for multiple target genes with high efficiency. Comparisons of 12 combinations of eight promoters and two terminators found that the efficiency of the egg cell-specific promoter-controlled CRISPR/Cas9 system depended on the presence of a suitable terminator, and the composite promoter generated by fusing two egg cell-specific promoters resulted in much higher efficiency of mutation in the T1 generation compared with the single promoters.
Sodium‐ion batteries capable of operating at rate and temperature extremes are highly desirable, but elusive due to the dynamics and thermodynamics limitations. Herein, a strategy of ...electrode–electrolyte interfacial chemistry modulation is proposed. The commercial hard carbon demonstrates superior rate performance with 212 mAh g−1 at an ultra‐high current density of 5 A g−1 in the electrolyte with weak ion solvation/desolvation, which is much higher than those in common electrolytes (nearly no capacity in carbonate‐based electrolytes). Even at −20 °C, a high capacity of 175 mAh g−1 (74 % of its room‐temperature capacity) can be maintained at 2 A g−1. Such an electrode retains 90 % of its initial capacity after 1000 cycles. As proven, weak ion solvation/desolvation of tetrahydrofuran greatly facilitates fast‐ion diffusion at the SEI/electrolyte interface and homogeneous SEI with well‐distributed NaF and organic components ensures fast Na+ diffusion through the SEI layer and a stable interface.
In a THF‐based electrolyte with a weak solvation structure, Na+ desolvation is fast and a uniform solid electrolyte interphase (SEI) with abundant NaF and organic compounds is generated on the commercial hard carbon anode. This greatly enhances the interface stability and enables the rapid migration of Na+ in the SEI, thus realizing the high rate capability, long‐term stability and good low‐temperature performance for the hard carbon anode.
It is still very urgent and challenging to simultaneously develop high‐rate and long‐cycle oxide cathodes for sodium‐ion batteries (SIBs) because of the sluggish kinetics and complex multiphase ...evolution during cycling. Here, the concept of accurately manipulating structural evolution and formulating high‐performance heterostructured biphasic layered oxide cathodes by local chemistry and orbital hybridization modulation is reported. The P2‐structure stoichiometric composition of the cathode material shows a layered P2‐ and O3‐type heterostructure that is explicitly evidenced by various macroscale and atomic‐scale techniques. Surprisingly, the heterostructured cathode displays excellent rate performance, remarkable cycling stability (capacity retention of 82.16% after 600 cycles at 2 C), and outstanding compatibility with hard carbon anode because of the integrated advantages of intergrowth structure and local environment regulation. Meanwhile, the formation process from precursors during calcination and the highly reversible dynamic structural evolution during the Na+ intercalation/deintercalation process are clearly articulated by a series of in situ characterization techniques. Also, the intrinsic structural properties and corresponding electrochemical behavior are further elucidated by the density of states and electron localization function of density functional theory calculations. Overall, this strategy, which finely tunes the local chemistry and orbitals hybridization for high‐performance SIBs, will open up a new field for other materials.
An abnormal heterostructured biphasic layered oxide cathode for sodium‐ion batteries (SIBs) is successfully constructed, and its dynamic formation process, intrinsic structural properties, and electrochemical behavior are elucidated by a series of in situ characterization techniques and density functional theory calculations. The concept of accurately manipulating structural evolution and formulating heterostructured cathode materials by local chemistry and orbital hybridization modulation is further demonstrated.
To accelerate the application of the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9) system to a variety of plant species, a toolkit with ...additional plant selectable markers, more gRNA modules, and easier methods for the assembly of one or more gRNA expression cassettes is required.
We developed a CRISPR/Cas9 binary vector set based on the pGreen or pCAMBIA backbone, as well as a gRNA (guide RNA) module vector set, as a toolkit for multiplex genome editing in plants. This toolkit requires no restriction enzymes besides BsaI to generate final constructs harboring maize-codon optimized Cas9 and one or more gRNAs with high efficiency in as little as one cloning step. The toolkit was validated using maize protoplasts, transgenic maize lines, and transgenic Arabidopsis lines and was shown to exhibit high efficiency and specificity. More importantly, using this toolkit, targeted mutations of three Arabidopsis genes were detected in transgenic seedlings of the T1 generation. Moreover, the multiple-gene mutations could be inherited by the next generation.
We developed a toolkit that facilitates transient or stable expression of the CRISPR/Cas9 system in a variety of plant species, which will facilitate plant research, as it enables high efficiency generation of mutants bearing multiple gene mutations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Enantiomerically enriched indole-containing heterocycles play a vital role in bioscience, medicine, and chemistry. As one of the most attractive subtypes of indole alkaloids, highly substituted ...tetrahydro-γ-carbolines are the basic structural unit in many natural products and pharmaceuticals. However, the syntheses of tetrahydro-γ-carbolines with high functionalities from readily available reagents are significant challenging. In particular, the stereodivergent syntheses of tetrahydro-γ-carbolines containing multi-stereogenic centers remain quite difficult. Herein, we report an expedient and stereodivergent assembly of tetrahydro-γ-carbolines with remarkably high levels of stereoselective control in an efficient cascade process from aldimine esters and indolyl allylic carbonates via a synergistic Cu/Ir catalyst system. Control experiments-guided optimization of synergistic catalysts and mechanistic investigations reveal that a stereodivergent allylation reaction and a subsequent highly stereoselective iso-Pictet-Spengler cyclization are the key elements to success.
Diacylglycerol kinase (DGK) is an enzyme that plays a pivotal role in abiotic and biotic stress responses in plants by transforming the diacylglycerol into phosphatidic acid. However, there is no ...report on the characterization of soybean
genes in spite of the availability of the soybean genome sequence. In this study, we performed genome-wide analysis and expression profiling of the
gene family in the soybean genome. We identified 12
genes (namely
) which all contained conserved catalytic domains with protein lengths and molecular weights ranging from 436 to 727 amino acids (aa) and 48.62 to 80.93 kDa, respectively. Phylogenetic analyses grouped
genes into three clusters-cluster I, cluster II, and cluster III-which had three, four, and five genes, respectively. The qRT-PCR analysis revealed significant
gene expression levels in both leaves and roots coping with polyethylene glycol (PEG), salt, alkali, and salt/alkali treatments. This work provides the first characterization of the
gene family in soybean and suggests their importance in soybean response to abiotic stress. These results can serve as a guide for future studies on the understanding and functional characterization of this gene family.
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•The characteristics of low temperature oxidation kinetics of water-soaked coal samples were analyzed.•Find out the migration law of functional groups in the oxygen-lean combustion ...process of water-soaked coal.•The thermal evolution process of water-soaked coal samples in an oxygen-lean environment is proposed.•A micro-reaction mechanism of coal-oxygen-water molecular chemisorption was constructed.
Oxidative spontaneous combustion is likely to occur after long-term water immersion in the gob area of coal mines. Mostly, the oxidation process is slowly carried out under different air leakage conditions. This paper summarizes the four stages of the low-temperature oxidation of water-soaked coal samples through temperature-programmed experiments. Using infrared spectroscopy and thermal analysis experiments, the migration laws of the functional groups and the thermal reaction characteristics of the four stages were investigated. The results show that as the oxygen concentration increases, the gas product concentration increases, and the activation energy of the deep oxidation stage decreases. With the progress of the heating stage, when the oxygen concentration is higher than 10%, the change in each functional group is larger, and the conversion of the functional group and the intermediate complex is relatively closer at an oxygen concentration of 21%. The low-temperature oxidation reaction is a parallel process of the pyrolysis and micro-oxygen absorption, and the DTG size is not affected by the oxygen concentration at the critical temperature. The higher the oxygen concentration is, the lower the initial exothermic temperature is, which promotes the exothermic process in the deep oxidation and oxidation-limited stages. The microreaction mechanism among coal, oxygen and water molecular chemisorption is constructed. By controlling the coal oxidation reaction stages under different air leakage conditions, the spontaneous combustion of water-soaked coal in the goaf is avoided.
Microbial corrosion of iron-based materials is a substantial economic problem. A mechanistic understanding is required to develop mitigation strategies, but previous mechanistic studies have been ...limited to investigations with relatively pure Fe(0), which is not a common structural material. We report here that the mechanism for microbial corrosion of stainless steel, the metal of choice for many actual applications, can be significantly different from that for Fe(0). Although H
is often an intermediary electron carrier between the metal and microbes during Fe(0) corrosion, we found that H
is not abiotically produced from stainless steel, making this corrosion mechanism unlikely. Geobacter sulfurreducens and Geobacter metallireducens, electrotrophs that are known to directly accept electrons from other microbes or electrodes, extracted electrons from stainless steel via direct iron-to-microbe electron transfer. Genetic modification to prevent H
consumption did not negatively impact on stainless steel corrosion. Corrosion was inhibited when genes for outer-surface cytochromes that are key electrical contacts were deleted. These results indicate that a common model of microbial Fe(0) corrosion by hydrogenase-positive microbes, in which H
serves as an intermediary electron carrier between the metal surface and the microbe, may not apply to the microbial corrosion of stainless steel. However, direct iron-to-microbe electron transfer is a feasible route for stainless steel corrosion.
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