Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 323
Filtrar
1.
Pathol Res Pract ; 234: 153914, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35523104

RESUMO

BACKGROUND: An increasing body of evidence suggest that circRNAs modulate various gene expression at the posttranscriptional level, affecting the development of cancers. Previous study suggested that circSPECC1 acted as an oncogene in some tumors, promoting the growth and metastasis of cancer cells. However, the role of circSPECC1 in bladder cancer (Bca) remains unknown. METHODS: RT-qPCR assay was applied to detect the expresion level of circRNA, miRNA and mRNA in Bca tissues and cells. CCK-8, cell colony formation and wound-healing assay were peformed to detect the effect of circSPECC1 on cell proliferation and migration. Nuclear mass separation, dual-luciferase reporter and RNA pull-down assay were used to investigate the molecular mechanisms underlying circSPECC1. RESULTS: In this study, we found that circSPECC1 was significantly up-regulated in Bca tissues and cell lines. Increased expression of circSPECC1 contribute to poor prognosis of Bca. Further tests showed that knockdown of circSPECC1 impaired the proliferation and migration of Bca cells. Mechanically, circSPECC1 sponged miR-136-5p to promote the mRNA and protein expression of GNAS. Besides, enforced expression of GNAS significantly reversed the proliferation and migration inhibition mediated by circSPECC1 suppression. CONCLUSION: In general, our study suggested that circSPECC1 contributed to the growth and metastasis of Bca and it is possible to become an ideal non-invasive biomarker for diagnosis and effective therapeutic target for treatment.

2.
Sci Data ; 9(1): 205, 2022 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-35562358

RESUMO

The published map recording cultural sites in Xinjiang shows that there is a lack of data collection on the distribution of sites in the area, and no relevant data sets have been released. Existing written materials indicate that there are more cultural sites in this area. For this reason, we have collected and sorted out information. Our cultural site database provides the geographic location and corresponding geographic environment of each site in Xinjiang from the Paleolithic to the Bronze Age. The data record the human development and settlement process, settlement environment landscape characteristics, scale, type, quantity, and spatial distribution in Xinjiang in prehistoric China. These data not only are the basis for further understanding the spatial distribution of prehistoric humans in Xinjiang, but also provide references for understanding prehistoric human behavior and prehistoric man-land relationship, and the exchange of eastern and western civilizations. It is of great significance to modern social planning, site protection, and resource utilization.

3.
Water Res ; 217: 118370, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35405553

RESUMO

Co-transport of colloidal substances and pollutants is a pivotal link that significantly affects the environment of coastal groundwater. The effect of colloid mobilization and aquifer pore structure change on heavy metal transport driven by seawater-freshwater interface dynamics is not fully understood. In this study, packed column experiments were conducted to model the seawater intrusion (SWI) and freshwater replenishment (FWR) processes using a sampled medium from a coastal sandy aquifer. Hydrodynamic, hydrochemical variables, and heavy metal (Pb, Cu, Cd) transport during the propagation of the seawater-freshwater interface were tested and analyzed. During the SWI stage, cation exchange induced heavy metal liberations, and it developed peak concentrations synchronized with the seawater-freshwater interface at the pore volume of 1.00. The colloid-facilitated transport for heavy metals was the predominant mechanism in the FWR stage, characterized by a peak release lagging the interface propagation by approximately 0.5 pore volumes. Because the colloidal fraction was mobilized during aquifer desalination, it lagged behind the decline of the salinity gradient. Furthermore, Derjaguin-Landau-Verwey-Overbeek (DLVO) calculations explained that the replenishment decreased the depth of the secondary energy minimum of the colloids; meanwhile, the thickness of the electrical double layer increased from 0.63 nm to 10.14 nm, resulting in a repulsive energy barrier up to 3,213 kT. The transport of colloids led to a reduction in porosity from 18.16% to 2.28% of the total immobile domain. At these times, the dimension of the transported colloids evolved, showing a size-selective transport and therefore regulating the total emission fluxes of the heavy metals. These mechanisms were proposed to be incorporated in colloid filtration theory for targeting the coastal scenario.

4.
Ann Transl Med ; 10(6): 349, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35434045

RESUMO

Background: Multiple clinical trials were conducted to evaluate the efficacy of neoadjuvant therapy in esophageal cancer but exhibited mixed results, indicating that the efficacy of neoadjuvant therapy remains controversial in the treatment of esophageal cancer. Our study was conducted to investigate the value of neoadjuvant therapy in patients with esophageal cancer with supraclavicular lymph node metastases. Methods: We retrospectively enrolled 231 patients who had resectable esophageal squamous cell carcinoma (ESCC) with supraclavicular lymph node metastases from June 2008 to November 2018. All patients were divided into three groups: the neoadjuvant therapy combined with surgery (Neo + S) group, the radical chemoradiotherapy (CRT) group, and the single radiotherapy (RT) group. Propensity score matching (PSM) was conducted to exclude the impact of potential interferences. Kaplan-Meier analysis, the log-rank test, and competitive risk model analysis were used to assess the efficacy of different therapeutic methods. Results: Patients in the Neo + S group had a better 3-year survival rate (72.0% vs. 35.8%; P=0.005), progression-free survival (PFS) (24 vs. 14 months; P<0.0001), and lower 3-year tumor-specific mortality risk (25.1% vs. 53.7%; P=0.005) than those in the CRT group. Furthermore, patients in the CRT group had a better 3-year survival (30.1% vs. 18.6%; P=0.012) and lower 3-year tumor-specific mortality risk (57.9% vs. 76.8%; P=0.011) than those in the RT group. Additionally, the supraclavicular lymph node metastasis rate was higher than the mediastinal lymph node metastasis rate in patients with upper esophageal cancer compared to middle and lower esophageal cancer. Conclusions: Neoadjuvant chemotherapy combined with surgery showed better efficacy than radical CRT in patients who had resectable ESCC with supraclavicular lymph nodes metastasis. Supraclavicular lymph nodes are more likely to be regional lymph nodes for upper and middle esophageal cancer.

5.
Biomed Chromatogr ; : e5380, 2022 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-35373846

RESUMO

Remdesivir (RDV), a phosphoramidate prodrug, has broad-spectrum antiviral activity. It is the first antiviral drug approved by the US Food and Drug Administration (FDA) for the treatment of COVID-19. Remdesivir is rapidly metabolized in the body to produce derivatives: alanine metabolite (RM-442) and RDV C-nucleoside (RN). Here, the phosphatase inhibitor PhosSTOP and carboxylesterase inhibitor 5,5'-dithiobis-2-nitrobenzoic acid were used to improve stability of RDV in mouse blood. We developed a rapid and sensitive LC-MS/MS method to simultaneously quantify RDV, RM-442 and RN in mouse blood. Chromatographic separation was achieved by gradient elution on an Acquity HSS T3 column. The run time was 3.2 min. The linearity ranges of the analytes were 0.5-1,000 ng/ml for RDV and 5-10,000 ng/ml for both RM-442 and RN. The method had an acceptable precision (RSD < 8.4% for RDV, RSD < 10.7% for RM-442 and RSD < 7.2% for RN) and accuracy (91.0-106.3% for RDV, 92.5-98.6% for RM-442 and 87.5-98.4% for RN). This method was successfully applied to analyze RDV, RM-442 and RN in the blood of normal and diabetic nephropathy DBA/2 J mice after intravenous injection of RDV at 20 mg/kg. The area under the concentration-time curve of RN between the normal and diabetic nephropathy mice showed a significant difference (P < 0.01).

6.
Dalton Trans ; 51(20): 7804-7810, 2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35441648

RESUMO

Exploring the facile synthesis of Pb-free energetic metal-organic frameworks (EMOFs) with both high nitrogen content and high thermostability is a significant but challenging task in the field of MOF-based green energetic materials. Herein, a new EMOF, [Zn2(atz)3(N3)]n (atz = 5-amino-1H-tetrazole), has been synthesized by simply using a commercial ligand (atz) under mild conditions. A probable mechanism for the formation of azide groups in the product has been proposed, in which the fraction of C-N and N-N bonds in atz is the key. The X-ray single crystal structure analysis reveals the EMOF's unique graphene-like and azide-group-bridged 2D bilayer structure with gourd-type micropores. More impressively, the EMOF shows a high nitrogen content of 59.33% and superior thermostability of up to 362 °C, both among the best of existing EMOFs. In addition, detonation property calculations and sensitivity tests have been carried out, which demonstrate its high-energy and low-sensitivity features. Moreover, [Zn2(atz)3(N3)]n shows the ability to accelerate the thermal decomposition of ammonium perchlorate (AP) and hexanitrohexaazaisowurtzitane (CL-20), making it a potential combustion promoter for green and insensitive propellants.

7.
Front Genet ; 13: 853028, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35422839

RESUMO

Au-Kline syndrome is a severe multisystemic syndrome characterized by several congenital defects, including intellectual disability. Loss-of-function and missense variants in the HNRNPK gene are associated with a range of dysmorphic features. This report describes an eleven-year-old Chinese boy with intellectual disability and developmental delays. Family-based whole-exome and Sanger sequencing identified a de novo missense variant in HNRNPK (NM_002140.3: c.143T > A, p. Leu48Val). In silico analysis predicted that this variant would be damaged in a highly conserved residue in the K homology 1 (KH1) domain. Bioinformatic analysis showed that the affinity change (ΔΔG) caused by this variant was -0.033 kcal/mol, indicating that it would have reduced affinity for RNA binding. Transcript analysis of the peripheral blood from this case found 42 aberrantly expressed and 86 aberrantly spliced genes (p-value <0.01). Functional enrichment analysis confirmed that the biological functions of these genes, including protein binding and transcriptional regulation, are associated with HNRNPK. In summary, this study identifies the first Chinese patient with a novel de novo heterozygous HNRNPK gene variant that contributes to Au-Kline syndrome and expands current knowledge of the clinical spectrum of HNRNPK variants.

8.
Sci Rep ; 12(1): 5072, 2022 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-35332226

RESUMO

When studying the human settlement process, it is of great significance to understand the prehistoric environment, economy and society by exploring the human-land relationship and the evolution of civilization reflected by the settlement environment. This paper explores the natural and social environmental preferences of early human settlements in Xinjiang, China, from the Palaeolithic to the Bronze Age (45 ka BP-2250 a BP). Through the characteristics of settlement preferences, the distribution of settlements is accurately predicted, and the relationship between settlement preferences and the evolution of the environment and civilization is verified and discussed. We summarize the needs and conditions of early human settlement from the perspectives of the social environment and natural environment and explain the stages, consistency and differentiation of the spatial and temporal evolution of settlement preferences with the interaction of adaptation and transformation. On this basis, we discuss the logical focuses and content of early human settlement preference research. This research provides a reference for the process, representation, driving mode, and research ideas of early human settlement preferences.


Assuntos
Meio Ambiente , Meio Social , China , Civilização , Humanos
9.
Small Methods ; 6(4): e2101467, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35247038

RESUMO

Cancer diagnosis and determining its tissue of origin are crucial for clinical implementation of personalized medicine. Conventional diagnostic techniques such as imaging and tissue biopsy are unable to capture the dynamic tumor landscape. Although circulating tumor DNA (ctDNA) shows promise for diagnosis, the clinical relevance of ctDNA remains largely undetermined due to several biological and technical complexities. Here, cancer stem cell-ctDNA is used to overcome the biological complexities like the inability for molecular analysis of ctDNA and dependence on ctDNA concentration rather than the molecular profile. Ultrasensitive quantum superstructures overcome the technical complexities of trace-level detection and rapid diagnosis to detect ctDNA within its short half-life. Activation of multiple surface enhanced Raman scattering mechanisms of the quantum superstructures achieved a very high enhancement factor (1.35 × 1011 ) and detection at ultralow concentration (10-15 M) with very high reliability (RSD: 3-12%). Pilot validation with clinical plasma samples from an independent validation cohort achieved a diagnosis sensitivity of ≈95% and specificity of 83%. Quantum superstructures identified the tissue of origin with ≈75-86% sensitivity and ≈92-96% specificity. With large scale clinical validation, the technology can develop into a clinically useful liquid biopsy tool improving cancer diagnostics.


Assuntos
Ácidos Nucleicos Livres , DNA Tumoral Circulante , Neoplasias , Ácidos Nucleicos Livres/genética , DNA Tumoral Circulante/genética , Genótipo , Humanos , Mutação , Células-Tronco Neoplásicas , Reprodutibilidade dos Testes
11.
Comput Math Methods Med ; 2022: 1991138, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35295201

RESUMO

With the continuous development of science and technology, people can apply more and more technology to the cultivation of children's abilities. In the process of cultivating children's ability, the most fancy is the study of executive function, and this is the research topic of this article. In the past, training methods such as music, mindfulness, and exercise have been used in the study of children's executive abilities to promote the development of preschool children's executive functions. While various approaches have had some effect, researchers have been exploring more comprehensive approaches to effective training. This article is aimed at studying how to use image recognition technology to conduct an intervention analysis of breakdancing in promoting the executive function of preschool children. For this reason, this paper proposes image recognition technology based on deep learning neural network and conducts research, analysis, and improvement on related technologies obtained from deep learning. This makes it more suitable for the research topic of this article and design-related experiments and analysis to explore its related performance. The experimental results in this paper show that the improved image recognition technology has improved accuracy by 31.2%. And the performance of its algorithm is also improved by 21%, which can be very effective in monitoring preschool children during breakdancing.


Assuntos
Desenvolvimento Infantil/fisiologia , Dança/fisiologia , Dança/psicologia , Função Executiva/fisiologia , Algoritmos , Pré-Escolar , Biologia Computacional , Aprendizado Profundo , Intervenção Educacional Precoce/métodos , Intervenção Educacional Precoce/estatística & dados numéricos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Masculino , Movimento/fisiologia , Redes Neurais de Computação
12.
Reproduction ; 163(5): 309-321, 2022 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-35275842

RESUMO

Decidualization of uterine stromal cells plays an important role in the establishment of normal pregnancy. Previous studies have demonstrated that Acyl-CoA binding protein (Acbp) is critical to cellular proliferation, differentiation, mitochondrial functions, and autophagy. The characterization and physiological function of Acbp during decidualization remain largely unknown. In the present study, we conducted the expression profile of Acbp in the endometrium of early pregnant mice. With the occurrence of decidualization, the expression of Acbp gradually increased. Similarly, Acbp expression was also strongly expressed in decidualized cells following artificial decidualization, both in vivo and in vitro. We applied the mice pseudopregnancy model to reveal that the expression of Acbp in the endometrium of early pregnant mice was not induced by embryonic signaling. Moreover, P4 significantly upregulated the expression of Acbp, whereas E2 appeared to have no regulating effect on Acbp expression in uterine stromal cells. Concurrently, we found that interfering with Acbp attenuated decidualization, and that might due to mitochondrial dysfunctions and the inhibition of fatty acid oxidation. The level of autophagy was increased after knocking down Acbp. During induced decidualization, the expression of ACBP was decreased with the treatment of rapamycin (an autophagy inducer), while increased with the addition of Chloroquine (an autophagy inhibitor). Our work suggests that Acbp plays an essential role in the proliferation and differentiation of stromal cells during decidualization through regulating mitochondrial functions, fatty acid oxidation, and autophagy.


Assuntos
Decídua , Inibidor da Ligação a Diazepam , Animais , Decídua/metabolismo , Inibidor da Ligação a Diazepam/metabolismo , Endométrio/metabolismo , Feminino , Camundongos , Gravidez , Pseudogravidez , Células Estromais/metabolismo
13.
Toxicol In Vitro ; 80: 105324, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35101544

RESUMO

In this study, the inhibitory effect of components from Chinese Herb Medicine (CHMs) with potential hepatotoxicity was assessed by human bile salt export pump (hBSEP) vesicles with and without S9 metabolism. Sixty-three compounds from 22 hepatoxicity CHMs were selected as the test articles. In hBSEP vesicles, eighteen of them were found to have moderate or strong inhibitory effect towards BSEP. Further studies were performed to determine the IC50 values of strong inhibitors. For the compounds belong to CHMs reported to cause cholestasis and strong inhibitors defined in hBSEP vesicles, their relative transport activities of Taurocholic acid (TCA) were evaluated in hBSEP vesicles as well as hBSEP vesicles with S9 system (S9/hBSEP vesicles). The differences of their relative transport activities of TCA between the above two system were compared to reveal the net effect of metabolism on BSEP's activity. It was found that the inhibitory effect of Saikogenin A (SGA), Saikogenin D (SGD), Diosbulbin B (DB) and rhein were significantly increased; while the inhibitory effect of isobavachalcone, saikosaponin d and saikosaponin b2 were significantly decreased after S9 metabolizing. Identification of metabolic pathways suggested that CYP3A4 was responsible for aggravating inhibitory effect of SGA and SGD against BSEP.


Assuntos
Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Medicamentos de Ervas Chinesas/toxicidade , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Colestase/metabolismo , Humanos , Fígado/metabolismo
14.
ACS Omega ; 7(4): 3359-3368, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35128246

RESUMO

Coal bunkers are relatively closed systems. Due to their own oxidation characteristics and the increase of temperature, spontaneous combustion will occur beyond the spontaneous combustion period. Moreover, spontaneous combustion of coal bunkers is a disaster caused by multifield coupling, so it is imperative to carry out inerting fire prevention and fire extinguishing. Based on this fact, combined with the actual situation in Huanghua Port, this paper establishes a two-dimensional geometric model of a coal bunker, selects CO2 as the inert gas sprayed in the coal bunker, determines the position of the inert gas port of the coal bunker hopper, and studies the influence of fireproof and fire-extinguishing inerting on coal bunker inerting. The results show that the arrangement of the inert gas port of the bunker hopper outside the bunker is more conducive to the diffusion of CO2 gas in the bunker. In about 35-41 days, the inerting temperature decreases slowly between 345 and 350 K. After 41 days, the maximum temperature of the coal bunker decreases rapidly and the spontaneous combustion of the coal bunker is completely controlled. Under the preset conditions, the best fire inerting time is 32.3 days after coal storage.

15.
Biochem Biophys Res Commun ; 598: 20-25, 2022 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-35149433

RESUMO

5- HT2A receptor is a member of the family A G-protein-coupled receptor. It is involved in many psychiatric disorders, such as depression, addiction and Parkinson's disease. 5-HT2AR targeted drugs play an important role in regulating cognition, memory, emotion and other physiological function by coupling G proteins, and their most notable function is stimulating the serotonergic hallucination. However, not all 5-HT2AR agonists exhibit hallucinogenic activity, such as lisuride. Molecular mechanisms of these different effects are not well illustrated. This study suggested that 5-HT2AR coupled both Gs and Gq protein under hallucinogenic agonists DOM and 25CN-NBOH stimulation, but nonhallucinogenic agonist lisuride and TBG only activates Gq signaling. Moreover, in head twitch response (HTR) model, we found that cAMP analogs 8-Bromo-cAMP and PDE4 inhibitor Rolipram could increase HTR, while Gs protein inhibitor Melittin could reduce HTR. Collectively, these results revealed that Gs signaling is a key signaling pathway that may distinguish hallucinogenic agonists and nonhallucinogenic agonists.


Assuntos
Subunidades alfa Gs de Proteínas de Ligação ao GTP/metabolismo , Alucinógenos/farmacologia , Movimentos da Cabeça/efeitos dos fármacos , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Animais , AMP Cíclico/metabolismo , Células HEK293 , Movimentos da Cabeça/fisiologia , Humanos , Lisurida/farmacologia , Masculino , Meliteno/farmacologia , Camundongos Endogâmicos C57BL , Rolipram/farmacologia , Transdução de Sinais/efeitos dos fármacos
16.
Artigo em Inglês | MEDLINE | ID: mdl-35169945

RESUMO

Exploring and utilizing the agronomic potential of deep-underground is one of the ways to cope with the challenges of sudden environmental change on agriculture. Understanding the effects of environmental stresses on the morphological and physiological indicators of crop seeds after their storage deep-underground is crucial to developing and implementing strategies for agriculture in the deep-underground space. In this study, we stored canola seeds in tunnels with horizontal depths of 0, 240, 690, and 1410 m in a gold mine. Seeds in envelopes were retrieved at 42, 66, 90, and 227 days of storage, whereas seeds in sealed packages were retrieved at 66 and 227 days of storage. The germination tests were conducted to investigate the effects of storage depth, duration, and packing method on stored and non-stored seeds. Results showed that increased depth and duration reduced seed germination rate, with the germination and vigor indexes also descending to varying degrees. Increased hypocotyl length and biomass accumulation suggested that deep-underground environment had a more significant compensatory effect on seed germination. For all indicators, the performance of seeds sealed in packages was superior to those stored in envelopes. Regression analysis showed that it was difficult to obtain the optimal value of each indicator simultaneously. The successful germination experiment foreshadowed the possibilities of deep-underground agriculture in the future.

17.
ACS Appl Mater Interfaces ; 14(5): 6370-6386, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35090345

RESUMO

Drug-resistant capacity in a small population of tumor-initiating cancer stem cells (tiCSCs) can be due to aberrant epigenetic changes. However, currently available conventional detection methods are inappropriate and cannot be applied to investigate the scarce population (tiCSCs). In addition, selective inhibitor drugs are shown to reverse epigenetic changes; however, each cancer type is discrete. Hence, it is essential to probe the resultant changes in tiCSCs even after therapy. Therefore, we have developed a multimode nanoplatform to investigate tiCSCs, detect epigenetic changes, and subsequently explore their transformation signals following drug therapy. We performed this by developing a surface-enhanced Raman scattering (SERS)-active nanoplatform integrated with n-dopant using an ultrafast laser ionization technique. The dopant functionalization enhances Raman scattering ability and permits label-free analysis of biomarkers in tiCSCs with the resolution down to the cellular level. Here, we investigated epigenetic biomarkers of tiCSCs in pancreatic and lung cancers. An extended study using inhibitor drugs demonstrates an unexpected increase of tiCSCs from lung cancer; this difference can be attributed to transformation changes in lung tiCSC. Thus, our work brings new insight into the differentiation abilities of CSCs upon epigenetic reversal, emphasizing unique perceptions in cancer treatment.


Assuntos
Nanoestruturas/química , Células-Tronco Neoplásicas/metabolismo , Biomarcadores Tumorais/genética , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Decitabina/química , Decitabina/farmacologia , Epigênese Genética , Humanos , Ácidos Hidroxâmicos/química , Ácidos Hidroxâmicos/farmacologia , Lasers , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Nanoestruturas/toxicidade , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Fósforo/química , Silício/química , Análise Espectral Raman
18.
Artigo em Inglês | MEDLINE | ID: mdl-35094284

RESUMO

Climate warming changes the plant community composition and biodiversity. Dominate species or plant functional types (PFTs) loss may influence alpine ecosystem processes, but much uncertainty remains. This study tested whether loss of specific PFTs and vegetation variation would impact the metallic element release of mixed litter in an alpine treeline ecotone. Six representative PFTs in the alpine ecosystem on the eastern Tibetan Plateau were selected. Litterbags were used to determine the release of potassium, calcium, magnesium, sodium, manganese, zinc, copper, iron, and aluminum from litter loss of specific PFTs after 669 days of decomposition in coniferous forest (CF) and alpine shrubland (AS). The results showed that potassium, sodium, magnesium, and copper were net released, while aluminum, iron, and manganese were accumulated after 669 days. Functional type mixtures promoted the release of potassium, sodium, aluminum, and zinc (synergistic effect), while inhibiting the release of calcium, magnesium, and iron (antagonistic effect). Further, loss of specific plant functional type significantly affected the aluminum and iron release rates and the relatively mixed effects of the potassium, aluminum, and iron release rates. The synergistic effects on potassium, sodium, and aluminum in AS were greater than those in CF, while the antagonistic effect of manganese release in AS was lower than that in CF. Therefore, increased altitude may further promote the synergistic effect of potassium, sodium, and aluminum release and alleviate the antagonistic effect of manganese in mixed litter. Finally, the initial stoichiometric ratios regulate the mixed effects of elemental release rates, with the nitrogen-related stoichiometric ratios playing the most important role. The regulation of elements release by stoichiometric ratios requires more in-depth and systematic studies, which will help us to understand the influence mechanism of decomposition more comprehensively.

19.
J Pept Sci ; 28(3): e3371, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34608710

RESUMO

A cathepsin B (Cat B)-responsive optical nanoprobe is designed and prepared for report of HL60 differentiation into macrophage. A peptide sequence FRFK is linked to fluorescein (FITC) via the distant amino group of its lysine and N-terminated with acrylic acid (AA) to yield a molecular fluorescent probe AA-FRFK (FITC). The molecular probe is further embedded in poly(lactic-co-glycolic acid) (PLGA) to form a fluorescent nanoprobe AA-FRFK (FITC)@PLGA. The resultant optical nanoprobe is degradable by lysosomal Cat B, which is expressed in macrophages with a level of 5-10 times of that in HL60 cells. As a result, a significant decrease in fluorescence intensity is associated with the differentiation process of HL60 to macrophage and can be used as an indication of the differentiation process. The findings may pave a way toward the development of a universal in vitro labeling strategy of exogenous stem cells for report of in vivo cell differentiation by a dual-mode imaging modality involving optical imaging and magnetic resonance imaging.


Assuntos
Catepsina B , Macrófagos , Diferenciação Celular , Fluoresceína-5-Isotiocianato/química , Células HL-60 , Humanos
20.
Sci Total Environ ; 803: 150122, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34525692

RESUMO

Loss of plant diversity affects mountain ecosystem properties and processes, yet few studies have focused on the impact of plant function type deficiency on mixed litter humification. To fill this knowledge gap, we conducted a 1279-day litterbag decomposition experiment with six plant functional types of foliar litter to determine the temporal dynamic characteristics of mixed litter humification in a coniferous forest (CF) and an alpine shrubland (AS). The results indicated that the humus concentrations, the net accumulations and their relative mixed effects (RME) of most types were higher in CF than those in AS at 146 days, and humus net accumulations fell to approximately -80% of the initial level within 1279 days. The RME of the total humus and humic acid concentrations exhibited a general change from synergistic to antagonistic effects over time, but the mixing of single plant functional type impeded the formation of fulvic acid due to consistently exhibited antagonistic effects. Ultimately, correlation analysis indicated that environmental factors (temperature, snow depth and freeze-thaw cycles) significantly hindered litter humification in the early stage, while some initial quality factors drove this process at a longer scale. Among these aspects, the concentrations of zinc, copper and iron, as well as acid-unhydrolyzable residue (AUR):nitrogen and AUR:phosphorous, stimulated humus accumulation, while water-soluble extractables, potassium, magnesium and aluminium hampered it. Deficiencies in a single plant functional type and vegetation type variations affected litter humification at the alpine treeline, which will further affect soil carbon sequestration, which is of great significance for understanding the material circulation of alpine ecosystems.


Assuntos
Ecossistema , Folhas de Planta , Florestas , Estações do Ano , Neve , Solo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...