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1.
Int J Mol Med ; 48(1)2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33955518

RESUMO

Women experience cognitive decline as they age due to the decrease in estrogen levels following menopause. Currently, effective pharmaceutical treatments for age­related cognitive decline are lacking; however, several Traditional Chinese medicines have shown promising effects. Lycium barbarum polysaccharides (LBPs) were found to exert a wide variety of biological activities, including anti­inflammatory, antioxidant and anti­aging effects. However, to the best of our knowledge, the neuroprotective actions of LBP on cognitive impairment induced by decreased levels of estrogen have not yet been determined. To evaluate the effects of LBP on learning and memory impairment in an animal model of menopause, 45 female ICR mice were randomly divided into the following three groups: i) Sham; ii) ovariectomy (OVX); and iii) OVX + LBP treatment. The results of open­field and novel object recognition tests revealed that mice in the OVX group had learning and memory impairments, and lacked the ability to recognize and remember new objects. Notably, these deficits were attenuated following LBP treatment. Immunohistochemical staining confirmed the protective effects of LBP on hippocampal neurons following OVX. To further investigate the underlying mechanism of OVX in mice, mRNA sequencing of the hippocampal tissue was performed, which revealed that the Toll­like receptor 4 (TLR4) inflammatory signaling pathway was significantly upregulated in the OVX group. Moreover, reverse transcription­quantitative PCR and immunohistochemical staining demonstrated that OVX induced hippocampal injury, upregulated the expression levels of TLR4, myeloid differentiation factor 88 and NF­κB, and increased the expression of TNF­α, IL­6 and IL­1ß inflammatory factors. Conversely, LBP treatment downregulated the expression levels of mRNAs and proteins associated with the TLR4/NF­κB signaling pathway, decreased the inflammatory response and reduced neuronal injury in mice that underwent OVX. In conclusion, the findings of the present study indicated that oral LBP treatment may alleviate OVX­induced cognitive impairments by downregulating the expression levels of mRNAs and proteins associated with the TLR4/NF­κB signaling pathway, thereby reducing neuroinflammation and damage to the hippocampal neurons. Thus, LBP may represent a potential agent for the prevention of learning and memory impairments in patients with accelerated aging caused by estrogen deficiency.

2.
Chem Commun (Camb) ; 2021 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33949486

RESUMO

Quinazoline skeletons are synthesized by amino acid catabolism/reconstruction combined with the insertion/cyclization of dimethyl sulfoxide for the first time. The amino acid acts as a carbon and nitrogen source through HI-mediated catabolism and is then reconstructed using aromatic amines and dimethyl sulfoxide (DMSO) as a one-carbon synthon. This protocol is of great significance for the further study of the conversion of amino acids.

3.
Chemistry ; 2021 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-33872429

RESUMO

We present here the synthesis of a novel fluorescent actinide polyrotaxane compound URCP1 through the utilization of an end-cutting pseudorotaxane precursor with only the cucurbit[6]uril (CB[6]) macrocyclic components acting as linking struts. The non-coordinating guest motif in the obtained polyrotaxane, with increased freedom and structural flexibility, can display intriguing temperature-triggered conformational variations inside the cavity of CB[6], which was clearly evidenced by crystallographic snapshots at different temperatures. Notably, this observation of temperature-triggered structural dynamics in URCP1 represents the first report of actinide polyrotaxane with such dynamics in solid-state. Moreover, URCP1 has a high photoluminescence quantum yield (PLQY) of 49.8%, comparable to other luminescent uranyl compounds, and can work as a fluorescent probe to selectively detect Fe 3+ over other eight competing cations in aqueous solution, with the limit of detection being as low as 4.4 × 10 -3 ppm.

4.
Dalton Trans ; 50(13): 4499-4503, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33877170

RESUMO

Herein, we report a new uranyl-organic polyhedron U4L4 (L = BTPCA) assembled from uranyl and a semirigid tritopic ligand. By adjusting the carbon chain length of organic templates, two complexes can be obtained based on the diverse secondary assembly of U4L4 cages. The mechanism of different arrangements of U4L4 cages induced by organic templates was explored in detail.

5.
Neurosci Lett ; 753: 135880, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33838256

RESUMO

Multiple sclerosis (MS) is mainly associated with the neuroinflammation and demyelination in the central nervous system (CNS), in which the failure of remyelination results in persistent neurological dysfunction. Fasudil, a typical Rho kinase inhibitor, has been exhibited beneficial effects on several models of neurodegenerative disorders. In this study, we showed that Fasudil promoted the uptake of myelin debris by microglia via cell experiments and through a cuprizone (CPZ)-induced demyelinating model. In vitro, microglia with phagocytic debris exhibited enhanced expression of brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF), and the conditioned medium promoted the maturation of oligodendrocyte precursor cells (OPCs). Meanwhile, Fasudil upregulated TREM2/DAP12 pathway, which positively regulated the phagocytosis of myelin debris by microglia. Similarly, in vivo, Fasudil intervention enhanced the clearance of myelin debris, upregulated the expression of BDNF and GDNF on microglia, and promoted the formation of Oligo2+/PDGFRα+ OPCs and the maturation of MBP + oligodendrocytes in the brain. Our results showed that Fasudil targeted the phagocytic function of microglia, effectively clearing myelin debris produced during pathological process possibly by upregulating TREM2/DAP12 pathway, accompanied by increased expression of BDNF and GDNF. However, the precise mechanism underlying the effects of Fasudil in promoting phagocytic effects and neurotrophic factors remains to be elucidated.

6.
Dalton Trans ; 50(10): 3559-3567, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33605961

RESUMO

Mutual separation of trivalent americium (Am3+) and curium (Cm3+) ions through liquid-liquid extraction is challenging due to the similarity in their chemical properties. Three N, O combined extractants 2,6-pyridinedicarboxylic acid di(N-ethyl-4-fluoroanilide) (Et(pFPh)DPA), diphenyl(2-pyridyl)phosphine oxide (Ph2PyPO), and alkyldiamide amine with 2-ethylhexylalkyl chains (ADAAM(EH)) have been identified to exhibit selectivity for Am3+ over Cm3+. In this work, the structures, bonding nature, and thermodynamic behaviors of a series of representative Am- and Cm-complexes with these ligands have been systematically investigated using density functional theory (DFT) calculations. Based on our calculations, the ONO angle formed by three donor atoms of the ligand in the Am-complex is slightly larger than that in its Cm-analogue. The studied ligands show their preference toward Am3+ by opening their "mouths" slightly wider. According to the Mayer bond order and the quantum theory of atoms in molecules (QTAIM) analyses, the interactions between the O donor atoms of these ligands and Am3+ and Cm3+ ions show some weak partial covalent character, and compared to the Am-O bond, there is relatively more covalency in the Cm-O bond in the corresponding complex. However, opposite results can be found in the Am-N and Cm-N bonding for the first two ligands. Particularly, for the better separation ligand ADAAM(EH), the Am-N and Cm-N interactions are extremely weak and no covalent character exists in the bonding. Nevertheless, the difference between the very weak Am-N and Cm-N interactions still leads to a better performance of ADAAM(EH). Based on the comparison of these ligands, we can find that weakening the binding ability of N atoms in the ligand may increase the difference between the Am-N and Cm-N interactions, thus enhancing the Am3+/Cm3+ separation ability of the ligand. Our study might provide new insights into understanding the selectivity of these three N, O combined ligands toward minor actinides and pave the way for designing efficient Am3+/Cm3+ extraction and separation ligands.

7.
J Nutr Biochem ; 90: 108570, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33429036

RESUMO

Optimizing diet quality in conjunction with statin therapy is currently the most common approach for coronary artery disease (CAD) risk management. Although effects on the cardiovascular system have been extensively investigated, little is known about the effect of these interventions in the colon and subsequent associations with CAD progression. To address this gap, Ossabaw pigs were randomly allocated to receive, for a six-month period, isocaloric amounts of either a heart healthy-type diet (HHD; high in unrefined carbohydrate, unsaturated fat, fiber, supplemented with fish oil, and low in cholesterol) or a Western-type diet (WD; high in refined carbohydrate, saturated fat and cholesterol, and low in fiber), without or with atorvastatin therapy. At the end of the intervention period, colon samples were harvested, mucosa fraction isolated, and RNA sequenced. Gene differential expression and enrichment analyses indicated that dietary patterns and atorvastatin therapy differentially altered gene expression, with diet-statin interactions. Atorvastatin had a more profound effect on differential gene expression than diet. In pigs not receiving atorvastatin, the WD upregulated "LXR/RXR Activation" pathway compared to pigs fed the HHD. Enrichment analysis indicated that atorvastatin therapy lowered inflammatory status in the HHD-fed pigs, whereas it induced a colitis-like gene expression phenotype in the WD-fed pigs. No significant association was identified between gene expression phenotypes and severity of atherosclerotic lesions in the left anterior descending-left circumflex bifurcation artery. These data suggested diet quality modulated the response to atorvastatin therapy in colonic mucosa, and these effects were unrelated to atherosclerotic lesion development.

8.
Gastroenterology ; 160(5): 1709-1724, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33421512

RESUMO

BACKGROUND & AIMS: Recent literature has implicated a key role for mast cells in murine models of colonic inflammation, but their role in human ulcerative colitis (UC) is not well established. A major advance has been the identification of mrgprb2 (human orthologue, MRGPX2) as mediating IgE-independent mast cell activation. We sought to define mechanisms of mast cell activation and MRGPRX2 in human UC. METHODS: Colon tissues were collected from patients with UC for bulk RNA sequencing and lamina propria cells were isolated for MRGPRX2 activation studies and single-cell RNA sequencing. Genetic association of all protein-altering G-protein coupled receptor single-nucleotide polymorphism was performed in an Ashkenazi Jewish UC case-control cohort. Variants of MRGPRX2 were transfected into Chinese hamster ovary (CHO) and human mast cell (HMC) 1.1 cells to detect genotype-dependent effects on ß-arrestin recruitment, IP-1 accumulation, and phosphorylated extracellular signal-regulated kinase. RESULTS: Mast cell-specific mediators and adrenomedullin (proteolytic precursor of PAMP-12, an MRGPRX2 agonist) are up-regulated in inflamed compared to uninflamed UC. MRGPRX2 stimulation induces carboxypeptidase secretion from inflamed UC. Of all protein-altering GPCR alleles, a unique variant of MRGPRX2, Asn62Ser, was most associated with and was bioinformatically predicted to alter arrestin recruitment. We validated that the UC protective serine allele enhances ß-arrestin recruitment, decreases IP-1, and increases phosphorylated extracellular signal-regulated kinase with MRGPRX2 agonists. Single-cell RNA sequencing defines that adrenomedullin is expressed by activated fibroblasts and epithelial cells and that interferon gamma is a key upstream regulator of mast cell gene expression. CONCLUSION: Inflamed UC regions are distinguished by MRGPRX2-mediated activation of mast cells, with decreased activation observed with a UC-protective genetic variant. These results define cell modules of UC activation and a new therapeutic target.

9.
J Nutr Biochem ; 90: 108577, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33388349

RESUMO

Diet quality and statin therapy are established modulators of coronary artery disease (CAD) progression, but their effect on the gastrointestinal tract and subsequent sequelae that could affect CAD progression are relatively unexplored. To address this gap, Ossabaw pigs (N = 32) were randomly assigned to receive isocaloric amounts of a Western-type diet (WD; high in saturated fat, refined carbohydrate, and cholesterol, and low in fiber) or a heart healthy-type diet (HHD; high in unsaturated fat, whole grains, fruits and vegetables, supplemented with fish oil, and low in cholesterol), with or without atorvastatin, for 6 months. At the end of the study, RNA sequencing with 100 base pair single end reads on NextSeq 500 platform was conducted in isolated pig jejunal mucosa. A two-factor edgeR analysis revealed that the dietary patterns resulted in three differentially expressed genes related to lipid metabolism (SCD, FADS1, and SQLE). The expression of these genes was associated with cardiometabolic risk factors and atherosclerotic lesion severity. Subsequent gene enrichment analysis indicated the WD, compared to the HHD, resulted in higher interferon signaling and inflammation, with some of these genes being significantly associated with serum TNF-α and/or hsCRP concentrations, but not atherosclerotic lesion severity. No significant effect of atorvastatin therapy on gene expression, nor its interaction with dietary patterns, was identified. In conclusion, Western and heart healthy-type dietary patterns differentially affect the expression of genes associated with lipid metabolism, interferon signaling, and inflammation in the jejunum of Ossabaw pigs.

10.
Inorg Chem ; 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33496591

RESUMO

Because H2O2 is thermally unstable, it seems to be difficult to synthesize peroxides at elevated temperatures. We describe here the in situ generation of peroxide that is incorporated in a new uranyl peroxo complex, HT-UPO1, through the hydrothermal treatment of uranyl nitrate at 150 °C in the presence of organic ligands. In this novel process, a highly conjugated aromatic carboxylate linker, (E)-4-[2-(pyridin-4-yl)vinyl]benzoic acid (HPyVB), plays a crucial role by inducing the reduction of oxygen in air to form peroxide in situ and coordinating with uranyl to promote the preferred formation of thermally stable HT-UPO1. This work expands our knowledge on the speciation and chemistry of uranyl peroxide compounds and also sheds light on the possibility of their synthesis under more harsh conditions.

11.
Inorg Chem ; 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319556

RESUMO

The design and development of a water-soluble heterocyclic ligand are believed to be an alternative way for improving the separation efficiency of actinides from lanthanides. Herein, we designed and synthesized a novel hydrophilic multidentate ligand: disulfonated N,N'-diphenyl-2,9-diamide-1,10-phenanthroline (DS-Ph-DAPhen) with soft and hard donor atoms, as a masking agent in aqueous solutions for Am(III) separation. The combination of N,N,N',N'-tetraoctyldiglycolamide in kerosene and DS-Ph-DAPhen in aqueous phases could separate Am(III) from Eu(III) across a range of nitric acid concentrations with very high selectivity. The coordination behaviors of Eu(III) with DS-Ph-DAPhen in aqueous solutions were studied by UV-vis titration, electrospray ionization mass spectrometry, and Fourier transform infrared spectra. The results indicated that Eu(III) ions could form both 1:1 and 1:2 complexes with the DS-Ph-DAPhen ligand in aqueous solution. Density functional theory calculation suggests that there are more covalent characters for Am-N bonds than that for Eu-N bonds in the complexes, which supports the better selectivity of the DS-Ph-DAPhen ligand toward Am(III) over Eu(III). This work demonstrates a feasible alternative approach to separating trivalent actinides from lanthanides with high selectivity.

12.
J Integr Neurosci ; 19(4): 651-662, 2020 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-33378839

RESUMO

Recent studies have shown that Nogo-A and the Nogo-A receptor affect ß-amyloid metabolism and the downstream Rho GTP enzyme signaling pathway, which may affect the levels of ß-amyloid and tau. Nogo-A may play a key role in the pathogenesis of Alzheimer's disease. However, the underlying molecular mechanisms of Fasudil treatment in Alzheimer's disease are not yet clear. Our results have found that Fasudil treatment for two months substantially ameliorated behavioral deficits, diminished ß-amyloid plaque and tau protein pathology, and alleviated neuronal apoptosis in APP/PS1 transgenic mice. More importantly, two well-established markers for synaptic function, growth-associated protein 43 and synaptophysin, were upregulated after Fasudil treatment. Finally, the levels of Nogo-A, Nogo-A receptor complex NgR/p75NTR/LINGO-1 and the downstream Rho/Rho kinase signaling pathway were significantly reduced. These findings suggest that Fasudil exerts its neuroprotective function in Alzheimer's disease by inhibiting the Nogo-A/NgR1/RhoA signaling pathway.

13.
Inorg Chem ; 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33382238

RESUMO

The stability of many MOFs is not satisfactory, which severely limits the exploration of their potential applications. Given this, we have proposed a strategy to improve the stability of MOFs by introducing alkali metal K+ capable of coordinating with metal nodes, which finally induces the interpenetrating uranyl-porphyrin framework to connect as a whole (IHEP-9). The stability experiments reveal that the IHEP-9 has good thermal stability up to 400 °C and can maintain its crystalline state in the aqueous solution with pH ranging from 2 to 11. The catalytic activity of IHEP-9 as a heterogeneous photocatalyst for CO2 cycloaddition under the driving of visible light at room temperature is also demonstrated. This induced interpenetration and fixation method may be promising for the fabrication of more functional MOFs with improved structural stability.

14.
Dalton Trans ; 49(44): 15895-15902, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33164010

RESUMO

To evaluate how halogen and actinide atoms affect the electronic structures and bonding nature, we have theoretically investigated a series of the actinide halides An(TRENTIPS)X (An = Th-Pu; X = F-I); several of them have been synthesized by Liddle's group. The An-X bond distances decrease from An = Th to Pu for the same halides, and the harmonic vibrational frequencies for the An-X bonds are more susceptible to being affected by the halogen atoms. The analyses of bonding nature reveal that the An-X bonds have a certain covalency with a polarized character, and the σ-bonding component in the total orbital contribution is greatly larger than the corresponding π-bonding ones based on the analysis of the NOCVs (the natural orbitals for chemical valence). Furthermore, the electronic structures of the thorium complexes are obviously different from those of the uranium and transuranic analogues due to more valence electrons in Th 6d orbitals. In addition, thermodynamic results suggest that the U(TRENTIPS)Br complex is the most stable and U(TRENTIPS)Cl has the highest reactivity based on the halide exchange reaction of U(TRENTIPS)X complexes using Me3SiX. The reduction ability of the tetravalent An(TRENTIPS)X is sensitive to halogen atoms according to the calculated electron affinity of the An(TRENTIPS)X and the reactions An(TRENTIPS)X + K → An(TRENTIPS) + KX. This work presents the effect of the halogen and the actinide atoms on the structures, bonding nature and redox ability of a series of the tetravalent actinide halides with TREN ligand and facilitates our in-depth understanding of f-block elements, which could provide theoretical guidance for experimental work on actinide halides, especially for the synthetic chemistry of transuranic halides.

15.
R Soc Open Sci ; 7(9): 200625, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33047026

RESUMO

The mechanisms underlying yak adaptation to high-altitude environments have been investigated using various methods, but no report has focused on long non-coding RNA (lncRNA). In the present study, lncRNAs were screened from the gluteus transcriptomes of yak and their transcriptional levels were compared with those in Sanjiang cattle, Holstein cattle and Tibetan cattle. The potential target genes of the differentially expressed lncRNAs between species/strains were predicted using cis and trans models. Based on cis-regulated target genes, no KEGG pathway was significantly enriched. Based on trans-regulated target genes, 11 KEGG pathways in relation to energy metabolism and three KEGG pathways associated with muscle contraction were significantly enriched. Compared with cattle strains, transcriptional levels of acyl-CoA dehydrogenase, acyl-CoA-binding protein, 3-hydroxyacyl-CoA dehydrogenase were relatively higher and those of glyceraldehyde 3-phosphate dehydrogenase, phosphoglycerate mutase 1, pyruvate kinase and lactate/malate dehydrogenase were relatively lower in yak, suggesting that yaks activated fatty acid oxidation but inhibited glucose oxidation and glycolysis. Besides, NADH dehydrogenase and ATP synthase showed lower transcriptional levels in yak than in cattle, which might protect muscle tissues from deterioration caused by reactive oxygen species (ROS). Compared with cattle strains, the higher transcriptional level of glyoxalase in yak might contribute to dicarbonyl stress resistance. Voltage-dependent calcium channel/calcium release channel showed a lower level in yak than in cattle strains, which could reduce the Ca2+ influx and subsequently decrease the risk of hypertension. However, levels of EF-hand and myosin were higher in yak than in cattle strains, which might enhance the negative effects of reduced Ca2+ on muscle contraction. Overall, the present study identified lncRNAs and proposed their potential regulatory functions in yak.

16.
BMC Evol Biol ; 20(1): 137, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33109104

RESUMO

BACKGROUND: On the Qinghai-Tibet Plateau, known as the roof ridge of the world, the yak is a precious cattle species that has been indispensable to the human beings living in this high-altitude area. However, the origin of domestication, dispersal route, and the divergence of domestic yaks from different areas are poorly understood. RESULTS: Here, we resequenced the genome of 91 domestic yak individuals from 31 populations and 1 wild yaks throughout China. Using a population genomics approach, we observed considerable genetic variation. Phylogenetic analysis suggested that the earliest domestications of yak occurred in the south-eastern QTP, followed by dispersal to the west QTP and northeast to SiChuang, Gansu, and Qinghai by two routes. Interestingly, we also found potential associations between the distribution of some breeds and historical trade routes such as the Silk Road and Tang-Tibet Ancient Road. Selective analysis identified 11 genes showing differentiation between domesticated and wild yaks and the potentially positively selected genes in each group were identified and compared among domesticated groups. We also detected an unbalanced pattern of introgression among domestic yak, wild yak, and Tibetan cattle. CONCLUSIONS: Our research revealed population genetic evidence for three groups of domestic yaks. In addition to providing genomic evidence for the domestication history of yaks, we identified potential selected genes and introgression, which provide a theoretical basis and resources for the selective breeding of superior characters and high-quality yak.


Assuntos
Bovinos/genética , Evolução Molecular , Variação Genética , Filogenia , Sequenciamento Completo do Genoma , Animais , China , Domesticação , Genoma , Genômica , Tibet
17.
J Am Chem Soc ; 142(39): 16538-16545, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32931700

RESUMO

The separation of actinides has a vital place in nuclear fuel reprocessing, recovery of radionuclides, and remediation of environmental contamination. Here we propose a new paradigm of nanocluster-based actinide separation, namely, nanoextraction, that can achieve efficient sequestration of uranium in an unprecedented form of giant coordination nanocages using a cone-shaped macrocyclic pyrogallol[4]arene as the extractant. The U24-based hexameric pyrogallol[4]arene nanocages with distinctive [U2(PG)2] binuclear units (PG = pyrogallol) that rapidly assembled in situ in monophasic solvent were identified by single-crystal X-ray diffraction, MALDI-TOF mass spectrometry, NMR spectroscopy, and small-angle X-ray and neutron scattering. Comprehensive biphasic extraction studies showed that this novel separation strategy has enticing advantages such as fast kinetics, high efficiency, and good selectivity over lanthanides, thereby demonstrating its potential for efficient separation of actinide ions.

18.
Inorg Chem ; 59(19): 14218-14228, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32914963

RESUMO

Diglycolamide-based ligands have recently received increased attention due to their outstanding affinity for trivalent actinides and lanthanides. The structure optimization of the ligands, however, still remains a hot topic to achieve better extraction performance. In this work, we prepare and investigate three multidentate diglycolamide ligands for the selective separation of Eu(III) over Am(III) from a nitric acid solution to explore the effect on the extraction of alkyl groups on the nitrogen atoms in the center of the BisDGA ligands. The introduction of ethyl or isopropyl groups on the central nitrogen atoms greatly increased the distribution ratios of trivalent metal ions and enhanced the separation factor of Eu(III) over Am(III). The complexation behaviors of Eu(III) and Am(III) ions were studied by slope analyses, electrospray ionization mass spectrometry (ESI-MS), and extended X-ray absorption fine structure (EXAFS) spectroscopy. The results indicated that the trivalent metal ions were extracted as 1:2 and 1:3 complexes for all three BisDGA ligands during the extraction. Density functional theory (DFT) calculations verified the relevant experimental conclusion that the selectivity of THEE-BisDGA for Eu(III) is better than that for Am(III). The metal-DGA bonds in the ML3(NO3)3 complexes seem to be stronger than those in ML2(NO3)3 complexes.

19.
Mol Ecol Resour ; 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32745324

RESUMO

Yak is an important livestock animal for the people indigenous to the harsh, oxygen-limited Qinghai-Tibetan Plateau and Hindu Kush ranges of the Himalayas. The yak genome was sequenced in 2012, but its assembly was fragmented because of the inherent limitations of the Illumina sequencing technology used to analyse it. An accurate and complete reference genome is essential for the study of genetic variations in this species. Long-read sequences are more complete than their short-read counterparts and have been successfully applied towards high-quality genome assembly for various species. In this study, we present a high-quality chromosome-scale yak genome assembly (BosGru_PB_v1.0) constructed with long-read sequencing and chromatin interaction technologies. Compared to an existing yak genome assembly (BosGru_v2.0), BosGru_PB_v1.0 shows substantially improved chromosome sequence continuity, reduced repetitive structure ambiguity, and gene model completeness. To characterize genetic variation in yak, we generated de novo genome assemblies based on Illumina short reads for seven recognized domestic yak breeds in Tibet and Sichuan and one wild yak from Hoh Xil. We compared these eight assemblies to the BosGru_PB_v1.0 genome, obtained a comprehensive map of yak genetic diversity at the whole-genome level, and identified several protein-coding genes absent from the BosGru_PB_v1.0 assembly. Despite the genetic bottleneck experienced by wild yak, their diversity was nonetheless higher than that of domestic yak. Here, we identified breed-specific sequences and genes by whole-genome alignment, which may facilitate yak breed identification.

20.
Inorg Chem ; 59(16): 11469-11480, 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32799470

RESUMO

Recovery of transplutonium elements from adjacent actinides is extremely complicated in spent fuel reprocessing. Uncovering the electronic structures of transplutonium compounds is essential for designing robust ligands for in-group separation of transplutonium actinides. Here, we demonstrate the in-group transplutonium actinides separation ability of the recent developed phenanthroline ligand Et-Tol-DAPhen (N2,N9-diethyl-N2,N9-di-p-tolyl-1,10-phenanthroline-2,9-dicarboxamide, La) and its derivatives (5-bromo-(N2,N9-diethyl-N2,N9-di-p-tolyl-1,10-phenanthroline-2,9-dicarboxamide, Lb), and 5-(4-(λ1-oxidaneyl)phenyl)-(N2,N9-diethyl-N2,N9-di-p-tolyl-1,10-phenanthroline-2,9- dicarboxamide, Lc) through quasi-relativistic density functional theory (DFT). Both electrostatic potential and molecular orbital analyses of the ligands indicate that the electron-donating group substituted ligand Lc is a better electron donor to actinides than La and Lb. The possible extracted complexes AnL(NO3)3 and [AnL2(NO3)]2+ (L = La, Lb, Lc; An = Am, Cm, Bk, Cf) possess similar structures. Bonding nature analysis validates that the covalent interactions of the metal-ligand bonds are enhanced across actinide series from Am to Cf, which stem from the energy degeneracy of the 5f orbitals of actinides and the 2p orbitals of the ligand coordinating atoms. The Lc ligand displays slightly stronger covalent bonding compared to the other two ligands. Simultaneously, thermodynamic analysis confirms the stronger metal-ligand bonding of the Cf3+ complexes and the higher stability of the extraction species with Lc. Consequently, the covalency between the DAPhen derivatives and transplutonium actinides seems to be positively correlated with the extraction ability of these ligands. Nevertheless, these ligands exhibit diverse separation abilities to in-group actinide recovery. Therefore, the enhancement of covalency does not necessarily lead to the improvement of separation ability due to different extraction capabilities. We hope that these results will provide some inspiration for designing novel ligands for in-group transplutonium separation.

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