Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.066
Filtrar
1.
Huan Jing Ke Xue ; 43(1): 398-408, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989524

RESUMO

In order to economically and efficiently remove dissolved organic matter (DOM) in the secondary water of wastewater treatment plants, this study adopted iron-nitrogen co-doped biochar material (Fe-N-C) as a new adsorbent and systematically analyzed the effect of this new carbon material on the secondary water DOM, as well as the adsorption performance, kinetic process, selectivity, and mechanism of action. In addition, the long-term performance and reusability of the adsorption material were thoroughly investigated through a fixed-bed adsorption device. The results show that Fe-N-C had outstanding adsorption performance for secondary water DOM. When the dosage was only 1.0 g·L-1, the removal rates of TOC, UV254, and UV280 were as high as 40.18%, 76.92%, and 78.26%, respectively, which are far higher. Regarding the adsorption effect of pure biochar and conventional activated carbon, the adsorption process conformed to the pseudo-second-order kinetics and Freundlich adsorption isotherm model, indicating that the adsorption process is a multilayer chemical adsorption involving valence electrons and the exchange of electrons. The three-dimensional fluorescence spectroscopy, molecular weight distribution, and resin analysis results, such as classification and characterization, showed that Fe-N-C had selective adsorption for different components in the secondary water DOM. The fixed bed adsorption column with Fe-N-C as the core had the maximum removal rate of secondary water TOC, UV254, and UV280 as high as 94.09%, 95.65%, and 97.18%, respectively, and had good stability. It was close to adsorption saturation when the processing capacity reached 620 times the bed volume. However, after the regeneration heat treatment, the adsorption performance was remarkably restored. These results are expected to provide reference for the further development of high-efficiency adsorption water treatment technology.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Adsorção , Ferro , Cinética , Nitrogênio , Poluentes Químicos da Água/análise
2.
Plant Physiol Biochem ; 171: 157-168, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34999507

RESUMO

Induced resistance is a promising strategy to manage plant disease, while adequate energy supply is crucial to plant defense. Our previous study has revealed that PpWRKY45 and PpWRKY70 are involved in MeJA-primed disease resistance by regulating jasmonate acid biosynthesis and phenylpropanoid metabolism. Herein, the possible role of WRKYs in MeJA-primed disease resistance and energy metabolism was investigated. PpWRKY46 and PpWRKY53 were up- and down-regulated, respectively, by MeJA treatment. The activities and gene expression of energy metabolism-related enzymes and energy status were promoted by MeJA treatment and R. stolonifer inoculation during 60 h storage at 20 °C. Energy metabolism-related genes, including PpSDH and PpCOX15 were transactivated by PpWRKY46, but repressed by PpWRKY53. Furthermore, PpWRKY46 interacted with PpWRKY53 to attenuate the transcriptional repression of PpWRKY53 to PpSDH and PpCOX15. Taken together, our results demonstrated that the counteraction of PpWRKY46 and PpWRKY53 contributes to MeJA-primed defense by regulating energy metabolism in peaches.

3.
Food Funct ; 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35028655

RESUMO

(-)-Epigallocatechin gallate (EGCG)-incorporated casein nanoparticles benefit from excellent antioxidant, anti-inflammatory and anti-cancer activities due to their synergistic efficiency, but few studies have evaluated their safety. In this study, the EGCG-casein nanoparticles (EGCG-NPs) formulated using caseinate by ultrasonic treatment were evaluated for their subacute toxicity. The subacute toxicity test of EGCG-NPs through 28-day oral administration in rats did not exhibit adverse effect, with a no-observed-adverse-effect level (NOAEL) of at least 5.0 g per kg body weight (BW) per day, which was equivalent to 500 mg per kg BW EGCG per day. However, the serum Na level in females and males treated with 10.0 g per kg BW EGCG-NPs increased significantly as compared to the control rats (P < 0.05). Similar indications appeared in rats treated with 10.0 g per kg BW pure casein nanoparticles without EGCG, which indicated that high doses of caseinate nanoparticles result in an excess serum Na level. Therefore, we should consider the safety of the nanoparticle formulation of caseinate when it is used as a loading nutrient and a functional substance in foods.

5.
J Sci Food Agric ; 102(2): 628-643, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34146341

RESUMO

BACKGROUND: Heat shock transcription factors (Hsfs) play pivotal roles in plant responses to stress. Although glycine betaine (GB) and hot water (HW) treatments are effective in reducing chilling injury (CI), little is known about the characterization of the Hsfs gene family and its potential roles in alleviating CI by regulating antioxidant systems in peach fruit. RESULTS: In this study, 17 PpHsfs were identified in the peach genome and were investigated using bioinformatics, including chromosomal locations, phylogenetic relationships, gene structure, motifs, and promoter analyses. The expression patterns of PpHsfs under GB and HW treatments were also investigated. The PpHsfs showed different expression patterns in GB- and HW-treated fruit, and most of them were significantly up-regulated by both treatments, especially PpHsfA1a/b, PpHsfA2a, PpHsfA9a, and PpHsfB2a/b. Meanwhile, GB and HW treatments induced higher levels of gene expression and antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) compared to the control, contributing to the inhibition of hydrogen peroxide (H2 O2 ) accumulation and superoxide anion (O2 .- ) production. Moreover, the correlation analysis between PpHsfs and antioxidant-related genes showed that three PpAPXs were significantly correlated with ten PpHsfs, whereas PpCAT and PpSOD had no significant correlations with PpHsfs, which indicated that PpAPX might be regulated by PpHsfs. CONCLUSIONS: The results indicated that GB and HW treatments induced different PpHsfs transcript levels to regulate the antioxidant gene expressions, which might be beneficial in inhibiting the accumulation of reactive oxygen species and protecting the integrity of cell structure, thus alleviating the development of CI in peach fruit during cold storage. © 2021 Society of Chemical Industry.


Assuntos
Antioxidantes/metabolismo , Betaína/farmacologia , Genoma de Planta , Fatores de Transcrição de Choque Térmico/genética , Proteínas de Plantas/genética , Prunus persica/efeitos dos fármacos , Ascorbato Peroxidases/genética , Ascorbato Peroxidases/metabolismo , Catalase/genética , Catalase/metabolismo , Armazenamento de Alimentos , Frutas/efeitos dos fármacos , Frutas/genética , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fatores de Transcrição de Choque Térmico/metabolismo , Temperatura Alta , Peróxido de Hidrogênio/metabolismo , Proteínas de Plantas/metabolismo , Prunus persica/genética , Prunus persica/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo
6.
Bioresour Technol ; 344(Pt B): 126361, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34801718

RESUMO

Paulownia biomass is rich in carbohydrates, making which a potential feedstock for biohydrogen production. In the study, different parts and varieties of Paulownia were chose as substrates to evaluate hydrogen production potential of paulownia lignocellulose via biohydrogen production by photo fermentation (BHPPF) and energy conversion efficiency (ECE). Results showed the highest cumulative hydrogen yield (CHY) of 67.11 mL/g total solids (TS) and ECE of 4.74% were obtained from leaves of Paulownia, which were 121.06% and 115.45% higher than those of the branches. Moreover, Paulownia jianshiensis leaves were found to be the best variety for BHPPF, with the maximum CHY of 98.83 mL/g TS and ECE of 7.18%. Using Paulownia waste as the substrate to produce hydrogen helps broaden the range of raw materials for BHPPF and improve the economic utilization of forestry waste.


Assuntos
Hidrogênio , Lignina , Biomassa , Fermentação , Hidrogênio/análise
7.
Sci Total Environ ; 805: 150260, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34537698

RESUMO

The performance of a permeable reactive barrier (PRB) for the in situ remediation of hexavalent chromium [Cr(VI)] contaminated groundwater, and the resulted responses in the indigenous microbial community, were investigated in a field-scale study. The PRB consisted of a mixture of zero-valent iron (ZVI), gravel and sand. The results showed that the PRB segment with 20% active reaction medium (ZVI) was able to successfully reduce Cr(VI) via chemical reduction from 27.29-242.65 mg/L to below the clean-up goal of 0.1 mg/L, and can be scaled-up under field conditions. It was found that the ZVI induced significant changes in the indigenous microbial community structure and compositions in the area of the PRB and those areas downgradient. The competitive growth among Cr(VI)-reducing bacteria (the reduced abundance of Hydrogenophaga, Pseudomonas, Exiguobacterium and Rhodobacter, along with the enrichment of Rivibacter and Candidatus_Desulforudis) were observed in PRB. In addition, Cr(VI)-reducing bacteria (Hydrogenophaga, Pseudomonas, Exiguobacterium and Rhodobacter) were enriched in the downgradient of PRB, indicating that Cr(VI) can be further bio-reduced to Cr(III). The Cr(VI) bio-reduction could serve as a secondary mechanism for further removal of Cr(VI) from contaminated groundwater, suggesting that the actual lifetime of a PRB can be prolonged, which is important for the design and economic assessment of a PRB. Further analysis revealed that pH, dissolved oxygen, Cr(VI) level, the oxidation-reduction potential, and temperature were the main environmental factors influencing the subsurface microbial community compositions.


Assuntos
Recuperação e Remediação Ambiental , Água Subterrânea , Microbiota , Poluentes Químicos da Água , Cromo/análise , Ferro , Poluentes Químicos da Água/análise
8.
Int J Womens Health ; 13: 1167-1174, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34876859

RESUMO

Objective: This paper analyzes the clinical significance of noninvasive prenatal testing (NIPT) for fetal chromosome aneuploidy in the screening of in vitro fertilization-embryo transfer (IVF) pregnancies. Methods: The study subjects consisted of 3163 IVF-pregnant women who underwent NIPT at the Women's Hospital, School of Medicine, Zhejiang University and Taizhou Hospital, Zhejiang Province from February 2015 to June 2019. Fetal or neonatal karyotype analysis was carried out in high-risk patients, with subsequent follow-up on pregnancy outcomes. Results: NIPT results of 3163 pregnant women suggested 20 cases of high-risk fetal chromosome aneuploidy, of which 2185 cases were a single pregnancy. Of the 13 cases of high-risk chromosome aneuploidy in single pregnancies, seven were true positive, and six were false positive according to fetal or newborn chromosomal karyotype diagnosis. Twin pregnancies accounted for 978 cases in which NIPT indicated seven cases of high-risk chromosome aneuploidy; six of these cases were true positive, and one case was false positive according to fetal or newborn chromosomal karyotype diagnosis. The specificity, positive predictive value, and false-positive rate of trisomy 21 syndrome in IVF single embryo NIPT were 99.86%, 62.5%, and 0.14%, respectively. The specificity, positive predictive value, and false-positive rate of trisomy 18 syndrome were 99.95%, 66.67%, and 0.05%, respectively. The specificity of trisomy 13 syndrome was 99.91%, and the false-positive rate was 0.09%. The specificity of trisomy 21 syndrome in IVF twin NIPT was 99.89%, the positive predictive value was 83.33%, and the false-positive rate was 0.11%. The specificity and positive predictive value of fetal trisomy 18 syndrome were 100.00%, and the false-positive rate of it were 0.00%. Sensitivity and false-negative rates were 100% in all cases. Conclusion: NIPT is an ideal prenatal test for IVF-pregnant women due to its high sensitivity and specificity in screening for fetal aneuploidy.

9.
Cancer Med ; 2021 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-34866356

RESUMO

BACKGROUND: The prognostic value of sarcopenia in combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) patients after surgery has not been evaluated, while the efficacy of the available tumor stage for cHCC-CC remains controversial. METHODS: All consecutive cHCC-CC patients after surgery were retrieved. The patients were stratified by the sex-specific medians of the psoas muscle index into groups with or without sarcopenia. Prognosis was analyzed using the Kaplan-Meier (K-M) method, and the K-M curves were adjusted by inverse probability weighting (IPW). A nomogram based on Cox regression analysis was established and further compared with primary liver cancer (PLC) stages by internal validation based on bootstrap resampling and k-fold cross-validation. RESULTS: A total of 153 patients were stratified into sarcopenia and non-sarcopenia groups. The sarcopenia group revealed statistically worse overall survival (OS) and disease-free survival (DFS) using the K-M method and K-M curves adjusted by IPW. Multivariate Cox regression analyses suggested sarcopenia as an independent risk factor for OS (HR = 1.55; p = 0.040) and DFS (HR = 1.55; p = 0.019). Subgroup analysis based on baseline variables showed sarcopenia as a stable risk factor for the prognosis. Our nomogram outperformed PLC stages in prognostic prediction, as evidenced by the best c-index, area under the curve, and positive improvement of the net reclassification index and integrated discrimination improvement. A fivefold cross-validation revealed consistent results. Decision curve analysis revealed higher net benefits of the nomogram than PLC stages. CONCLUSIONS: Sarcopenia is an independent and stable risk factor for the prognosis of cHCC-CC patients after surgery. Our nomogram might aid high-risk patient identification and clinical decisions.

10.
Artigo em Inglês | MEDLINE | ID: mdl-34859268

RESUMO

The biological process to remove nitrogen in winter effluent is often seriously compromised due to the effect of low temperatures (< 13 °C) on the metabolic activity of microorganisms. In this study, a novel heterotrophic nitrifying-aerobic denitrifying bacterium with cold tolerance was isolated by iterative domestication and named Moraxella sp. LT-01. The LT-01 maintained almost 60% of its maximal growth activity at 10 °C. Under initial concentrations of 100 mg/L, the removal efficiencies of ammonium, nitrate, nitrite by LT-01 were 70.3%, 65.4%, 61.7% respectively for 72 h incubation at 10 °C. Nitrogen balance analysis showed that about 46% of TN was released as gases and 16% of TN was assimilated for cell growth. The biomarker genes involved in nitrification and denitrification pathways were identified by gene-specific PCR and revealed that the LT-01 has nitrite reductase (NirS) but not hydroxylamine reductase (HAO), which implies the involvement of other genes in the process. The study indicates that LT-01 has the potential for use in low-temperature regions for efficient sewage treatment.

11.
Artigo em Inglês | MEDLINE | ID: mdl-34933958

RESUMO

BACKGROUND: The most widely used non-invasive screening tests for colorectal cancer (CRC) are faecal occult blood tests. Stool DNA test was developed in recent years. However, direct comparative analyses of these tests within the same population are still sparse. METHODS: 2842 participants who visited outpatient clinics or cancer screening centres were enrolled. Stool DNA test-I (KRAS, BMP3, NDRG4, and haemoglobin immunochemical tests), stool DNA test-II (SDC2 and SFRP2 tests) and FIT alone were performed and colonoscopy was used as the gold standard among 2240 participants. 42 and 302 participants had CRC and advanced adenomas (AA), respectively. RESULTS: The sensitivity for CRC of stool DNA test-I, -II and FIT was 90.5%, 92.9% and 81.0%, respectively. The sensitivity for advanced neoplasm (CRC plus AA) of stool DNA test-I, -II and FIT was 34.9%, 42.2% and 25.9%, respectively. The specificity of stool DNA test-I, -II and FIT was 91.4%, 93.3% and 96.8%, respectively, among those with negative results on colonoscopy. When the specificity of FIT was adjusted to match that of stool DNA tests by changing the threshold, no significant difference was seen in the sensitivities among the 3 tests for detecting CRC. For advanced neoplasm, the sensitivity of FIT was higher than DNA test-I and similar to DNA test-II under the same specificities. CONCLUSIONS: There was no significant advantage of the two stool DNA tests compared to FIT in detecting CRC or advanced neoplasm in this study. IMPACT: Our findings do not support extensive use of stool DNA tests instead of FIT.

12.
J Food Sci ; 2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34914095

RESUMO

4'-O-methylpyridoxine (MPN), a recognized antivitamin B6 compound, is a potentially poisonous substance found in Ginkgo biloba L. In this work, the effects of MPN on the metabolism of vitamin B6 , neurotransmitters, and amino acids were compared in the plasma and brain of young and adult rats under various administration times. Results showed that the contents of MPN residues in the plasma and brain of young rats were 12.72 and 14.76 µM higher than adult rats, respectively. Moreover, the levels of 5-hydroxytryptamine and dopamine in the brain of young rats have decreased by 13.78% and 7.19%, respectively, compared with the control group, at 2 h after MPN administration. Furthermore, the principal component analysis revealed that MPN was an important contributor to the amino acid composition in the brain of young rats. These results suggest that age may lead to different toxic effects of MPN. PRACTICAL APPLICATION: 4'-O-methylpyridoxine is primarily responsible for poisoning due to overconsumption of Ginkgo biloba seeds. This study will provide an exploratory understanding of the age-dependent toxicity of 4'-O-methylpyridoxine.

13.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 46(11): 1220-1226, 2021 Nov 28.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-34911856

RESUMO

OBJECTIVES: Urinary tract infection (UTI) is the most common infection complication after kidney transplantation, and the reports of the incidence vary greatly among different centers. This study aims to explore the risk factors for UTI after kidney transplantation with the donation from brain death (DBD) and the impact on graft function, thus to provide theoretical basis for comprehensive prevention and treatment of UTI after kidney transplantation. METHODS: The clinical and laboratory data of DBD kidney transplantation from January 2017 to December 2018 in Xiangya Hospital, Central South University were collected and retrospectively analyzed. Patients were assigned into an UTI group and a non-UTI group. The base line characteristics, post-transplant complications, and graft function were compared between the 2 groups. Multivariate logistic regression was used to analyze the risk factors for UTI. RESULTS: A total of 212 DBD kidney transplant recipients were enrolled in this study. UTI occurred in 44 (20.75%) patients after transplantation. The female, the time of indwelling catheter, and postoperative urinary fistula were independent risk factors for UTI after DBD kidney transplantation. A total of 19 strains of gram-positive bacteria, 12 strains of gram-negative bacteria , and 10 strains of fungi were isolated from the urine of 44 UTI patients. The UTI after kidney transplantation significantly increased time of hospital stay (P<0.001) and raised the cost for antibiotics (P=0.004). The graft function was much worse in the UTI group compared with the non-UTI group (P<0.001) at 3 months after transplantation. Twenty (45.45%) patients recurred UTI within one year after transplantation. Non-hemodialysis before transplantation and perioperative combination of antibacterial and antifungal drugs were independent risk factors for recurrence of UTI. CONCLUSIONS: UTI after DBD kidney transplantation transplantation affects the renal function at 3 months and increases the patient's economic burden.


Assuntos
Transplante de Rim , Infecções Urinárias , Morte Encefálica , Feminino , Humanos , Transplante de Rim/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Infecções Urinárias/epidemiologia , Infecções Urinárias/etiologia
14.
Hum Mol Genet ; 2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34897434

RESUMO

RNA modifications affect many aspects of RNA metabolism and are involved in the regulation of many different biological processes. Mono-methylation of adenosine in the N1 position, N1-methyladensoine (m1A), is a reversible modification that is known to target rRNAs and tRNAs. m1A has been shown to increase tRNA structural stability and induce correct tRNA folding. Recent studies have begun to associate the dysregulation of epitranscriptomic control with age-related disorders such as Alzheimer's disease. Here, we applied the newly developed m1A-quant-seq approach to map the brain abundant m1A RNA modification in the cortex of an Alzheimer's disease mouse model, 5XFAD. We observed hypomethylation in both mitochondrial and cytosolic tRNAs in 5XFAD mice compared to wild type. Furthermore, the main enzymes responsible for the addition of m1A in mitochondrial (TRMT10C, HSD17B10) and cytosolic tRNAs (TRMT61A) displayed decreased expression in 5XFAD compared to wild type mice. Knockdown of these enzymes results in a more severe phenotype in a Drosophila tau model, and differential m1A methylation is correlated with differences in mature mitochondrial tRNA expression. Collectively, this work suggests that hypo m1A modification in tRNAs may play a role in Alzheimer's disease pathogenesis.

15.
Front Nutr ; 8: 786571, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34938762

RESUMO

In this study, we explored the effect of Lactobacillus plantarum FZU3013-fermented Laminaria japonica (LPLJ) supplementation to prevent hyperlipidaemia in rats fed with a high-fat diet (HFD). The results indicate that LPLJ supplementation improved serum and hepatic biochemical indicators (p < 0.05), elevated short-chain fatty acid levels, reduced HFD-induced accumulation of lipid droplets in the liver, modulated the relative abundance of some microbial phylotypes, and reduced hyperlipidaemia in HFD-fed rats by adjusting the aminoacyl-tRNA, phenylalanine, tyrosine, and tryptophan biosynthetic pathways, as well as the phenylalanine, D-glutamine and D-glutamate, and glutathione metabolic pathways. Additionally, hepatic mRNA levels of the genes involved in lipid metabolism and bile acid homeostasis were significantly reduced by LPLJ intervention (p < 0.05). These results suggest that LPLJ has a positive effect on modulating lipid metabolism and has the potential to be a functional food that can help prevent hyperlipidaemia.

16.
New Phytol ; 2021 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-34907539

RESUMO

Phytoplankton are responsible for nearly half of global primary productivity and play crucial roles in the Earth's biogeochemical cycles. However, the long-term adaptive responses of phytoplankton to rising CO2 remains unknown. Here we examine the physiological and proteomics responses of a marine diatom, Phaeodactylum tricornutum, following long-term (c. 900 generations) selection to high CO2 conditions. Our results show that this diatom responds to long-term high CO2 selection by downregulating proteins involved in energy production (Calvin cycle, tricarboxylic acid cycle, glycolysis, oxidative pentose phosphate pathway), with a subsequent decrease in photosynthesis and respiration. Nearly similar extents of downregulation of photosynthesis and respiration allow the high CO2 -adapted populations to allocate the same fraction of carbon to growth, thereby maintaining their fitness during the long-term high CO2 selection. These results indicate an important role of metabolism reduction under high CO2 and shed new light on the adaptive mechanisms of phytoplankton in response to climate change.

17.
Vaccine ; 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34844823

RESUMO

Oral vaccination is the most convenient method for disease protection in aquaculture due to possibility of adding vaccines as part of fish diet. However, low protective efficiency is the major problem of oral vaccination owing to some reasons, especially for antigens degradation. In this study, we developed an oral inactivated vaccine based on a chitosan/aluminum adjuvant system, and investigated immune response induced by the vaccine. As a result, Th1 and Th2 cells mediated immune responses were observed after the vaccination according to the upregulation of IL-6, IL-12, IFNγ and IgM genes expression that were deemed as the driver cytokines for triggering the responses. Moreover, ratio of IgT+/IgM+ B cells was elevated in intestine after vaccination, while IgM antibodies were also observed in the sera of vaccinated fish, suggested that both local and systemic immune responses were induced by the inactivated vaccine. Totally, this oral vaccine can be used for V. anguillarum protection and this chitosan/aluminum system is an efficient candidate adjuvant for developing more vaccines in the future.

18.
Nat Commun ; 12(1): 6908, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34824289

RESUMO

Numerous single crystals that exhibit single-crystal-to-single-crystal (SCSC) transformations have been reported, and some of them show great promise for application to advanced adsorption materials, magnetic switches, and smart actuators. However, the development of single crystals with super-adaptive crystal lattices capable of huge and reversible structural change remains a great challenge. In this study, we report a ZnII complex that undergoes giant SCSC transformation induced by a two-step thermal elimination of ethylene glycol chelating ligands. Although the structural change is exceptionally large (50% volume shrinkage and 36% weight loss), the single-crystal nature of the complex persists because of the multiple strong hydrogen bonds between the constituent molecules. This allows the reversible zero-dimensional to one-dimension and further to three-dimensional structural changes to be fully characterized by single-crystal X-ray diffraction analyses. The elimination of chelating ligands induces a chiral interconversion in the molecules that manifests as a centric-chiral-polar symmetric variation of the single crystal. The study not only presents a unique material, featuring both a periodic crystal lattice and gel-like super-ductility, but also reveals a possible solid-state reaction method for preparing chiral compounds via the elimination of chelating ligands.

19.
Int Immunopharmacol ; : 108332, 2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34785141

RESUMO

Clinical studies have shown that dexmedetomidine (DEX) reduces mortality and inflammation in patients with sepsis, and ameliorates cognitive decline in both postoperative and critical care patients. This study aims to explain the neuroprotective effects provided by DEX in mice with cecal ligation and puncture (CLP)-induced polymicrobial sepsis. Mice were treated with DEX intraperitoneally three times every two hours after CLP. The survival rate, body weight, and clinical scores were recorded each day. Morris water maze (MWM) and fear conditioning tests were used to evaluate cognitive function. Blood brain barrier (BBB) permeability, hippocampal inflammation, hippocampal neural apoptosis, and T helper (Th) cell subgroups were assessed. Furthermore, Atipamezole was used to verify that the potential neuroprotective effects in the sepsis-associated encephalopathy (SAE) were mediated by DEX. Compared with the Sham group, CLP mice showed significant cognitive impairment, BBB interruption, excessive neuroinflammation, and neuronal apoptosis. These detrimental effects of CLP were attenuated by DEX. Furthermore, we found that DEX corrects peripheral Th1/Th2/Th17 shift and reduces proinflammatory cytokines in the hippocampus. Additionally, atipamezole prevented DEX's protective effect. Taken together, DEX alleviates cognitive impairments by reducing blood-brain barrier interruption and neuroinflammation by regulating Th1/Th2/Th17 polarization.

20.
Nature ; 600(7887): 164-169, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34789875

RESUMO

In the clades of animals that diverged from the bony fish, a group of Mas-related G-protein-coupled receptors (MRGPRs) evolved that have an active role in itch and allergic signals1,2. As an MRGPR, MRGPRX2 is known to sense basic secretagogues (agents that promote secretion) and is involved in itch signals and eliciting pseudoallergic reactions3-6. MRGPRX2 has been targeted by drug development efforts to prevent the side effects induced by certain drugs or to treat allergic diseases. Here we report a set of cryo-electron microscopy structures of the MRGPRX2-Gi1 trimer in complex with polycationic compound 48/80 or with inflammatory peptides. The structures of the MRGPRX2-Gi1 complex exhibited shallow, solvent-exposed ligand-binding pockets. We identified key common structural features of MRGPRX2 and describe a consensus motif for peptidic allergens. Beneath the ligand-binding pocket, the unusual kink formation at transmembrane domain 6 (TM6) and the replacement of the general toggle switch from Trp6.48 to Gly6.48 (superscript annotations as per Ballesteros-Weinstein nomenclature) suggest a distinct activation process. We characterized the interfaces of MRGPRX2 and the Gi trimer, and mapped the residues associated with key single-nucleotide polymorphisms on both the ligand and G-protein interfaces of MRGPRX2. Collectively, our results provide a structural basis for the sensing of cationic allergens by MRGPRX2, potentially facilitating the rational design of therapies to prevent unwanted pseudoallergic reactions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...