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1.
Biochem Biophys Res Commun ; 714: 149956, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38663095

RESUMO

BACKGROUND: Maize is a major cereal crop world widely, however, the yield of maize is frequently limited by dehydration and even death of plants, which resulted from osmotic stress such as drought and salinity. Dissection of molecular mechanisms controlling stress tolerance will enable plant scientists and breeders to increase crops yield by manipulating key regulatory components. METHODS: The candidate OSR1 gene was identified by map-based cloning. The expression level of OSR1 was verified by qRT-PCR and digital PCR in WT and osr1 mutant. Electrophoretic mobility shift assay, transactivation activity assay, subcellular localization, transcriptome analysis and physiological characters measurements were conducted to analyze the function of OSR1 in osmotic stress resistance in maize. RESULTS: The osr1 mutant was significantly less sensitive to osmotic stress than the WT plants and displayed stronger water-holding capacity, and the OSR1 homologous mutant in Arabidopsis showed a phenotype similar with maize osr1 mutant. Differentially expressed genes (DEGs) were identified between WT and osr1 under osmotic stress by transcriptome analysis, the expression levels of many genes, such as LEA, auxin-related factors, PPR family members, and TPR family members, changed notably, which may primarily involve in osmotic stress or promote root development. CONCLUSIONS: OSR1 may serve as a negative regulatory factor in response to osmotic stress in maize. The present study sheds new light on the molecular mechanisms of osmotic stress in maize.


Assuntos
Regulação da Expressão Gênica de Plantas , Pressão Osmótica , Proteínas de Plantas , Fatores de Transcrição , Zea mays , Zea mays/genética , Zea mays/metabolismo , Zea mays/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Mutação , Estresse Fisiológico/genética , Perfilação da Expressão Gênica
2.
Molecules ; 29(13)2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38999110

RESUMO

Electrochemical biosensors have emerged as powerful tools for the ultrasensitive detection of lung cancer biomarkers like carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), and alpha fetoprotein (AFP). This review comprehensively discusses the progress and potential of nanocomposite-based electrochemical biosensors for early lung cancer diagnosis and prognosis. By integrating nanomaterials like graphene, metal nanoparticles, and conducting polymers, these sensors have achieved clinically relevant detection limits in the fg/mL to pg/mL range. We highlight the key role of nanomaterial functionalization in enhancing sensitivity, specificity, and antifouling properties. This review also examines challenges related to reproducibility and clinical translation, emphasizing the need for standardization of fabrication protocols and robust validation studies. With the rapid growth in understanding lung cancer biomarkers and innovations in sensor design, nanocomposite electrochemical biosensors hold immense potential for point-of-care lung cancer screening and personalized therapy guidance. Realizing this goal will require strategic collaboration among material scientists, engineers, and clinicians to address technical and practical hurdles. Overall, this work provides valuable insight for developing next-generation smart diagnostic devices to combat the high mortality of lung cancer.


Assuntos
Biomarcadores Tumorais , Técnicas Biossensoriais , Técnicas Eletroquímicas , Neoplasias Pulmonares , Humanos , Biomarcadores Tumorais/análise , Neoplasias Pulmonares/diagnóstico , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Antígeno Carcinoembrionário/análise , Antígeno Carcinoembrionário/sangue , Nanocompostos/química , Grafite/química
3.
J Biol Chem ; 295(16): 5461-5469, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32184352

RESUMO

Telomeres are specific nucleoprotein structures that are located at the ends of linear eukaryotic chromosomes and play crucial roles in genomic stability. Telomere DNA consists of simple repeats of a short G-rich sequence: TTAGGG in mammals and TTTAGGG in most plants. In recent years, the mammalian telomeric G-rich repeats have been shown to form G-quadruplex (G4) structures, which are crucial for modulating telomere functions. Surprisingly, even though plant telomeres are essential for plant growth, development, and environmental adaptions, only few reports exist on plant telomeric G4 DNA (pTG4). Here, using bulk and single-molecule assays, including CD spectroscopy, and single-molecule FRET approaches, we comprehensively characterized the structure and dynamics of a typical plant telomeric sequence, d[GGG(TTTAGGG)3]. We found that this sequence can fold into mixed G4s in potassium, including parallel and antiparallel structures. We also directly detected intermediate dynamic transitions, including G-hairpin, parallel G-triplex, and antiparallel G-triplex structures. Moreover, we observed that pTG4 is unfolded by the AtRecQ2 helicase but not by AtRecQ3. The results of our work shed light on our understanding about the existence, topological structures, stability, intermediates, unwinding, and functions of pTG4.


Assuntos
Cromossomos de Plantas/genética , Quadruplex G , Telômero/química , Proteínas de Arabidopsis/metabolismo , Instabilidade Genômica , RecQ Helicases/metabolismo , Telômero/genética
4.
Molecules ; 26(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672940

RESUMO

Pseudomonas is considered as the specific spoilage bacteria in meat and meat products. The purpose of this study was to evaluate the inactivation efficiency and mechanisms of slightly acidic electrolyzed water (SAEW) against Pseudomonas deceptionensis CM2, a strain isolated from spoiling chicken breast. SAEW caused time-dependent inactivation of P. deceptionensis CM2 cells. After exposure to SAEW (pH 5.9, oxidation-reduction potential of 945 mV, and 64 mg/L of available chlorine concentration) for 60 s, the bacterial populations were reduced by 5.14 log reduction from the initial load of 10.2 log10 CFU/mL. Morphological changes in P. deceptionensis CM2 cells were clearly observed through field emission-scanning electron microscopy as a consequence of SAEW treatment. SAEW treatment also resulted in significant increases in the extracellular proteins and nucleic acids, and the fluorescence intensities of propidium iodide and n-phenyl-1-napthylamine in P. deceptionensis CM2 cells, suggesting the disruption of cytoplasmic and outer membrane integrity. These findings show that SAEW is a promising antimicrobial agent.


Assuntos
Ácidos/farmacologia , Membrana Celular/patologia , Eletrólise , Viabilidade Microbiana/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Água/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , Permeabilidade da Membrana Celular/efeitos dos fármacos , Citoplasma/efeitos dos fármacos , Desinfecção , Pseudomonas/citologia , Pseudomonas/ultraestrutura
5.
Neuroimage ; 206: 116226, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31593792

RESUMO

Accurate prediction of individuals' brain age is critical to establish a baseline for normal brain development. This study proposes to model brain development with a novel non-negative projective dictionary learning (NPDL) approach, which learns a discriminative representation of multi-modal neuroimaging data for predicting brain age. Our approach encodes the variability of subjects in different age groups using separate dictionaries, projecting features into a low-dimensional manifold such that information is preserved only for the corresponding age group. The proposed framework improves upon previous discriminative dictionary learning methods by incorporating orthogonality and non-negativity constraints, which remove representation redundancy and perform implicit feature selection. We study brain development on multi-modal brain imaging data from the PING dataset (N = 841, age = 3-21 years). The proposed analysis uses our NDPL framework to predict the age of subjects based on cortical measures from T1-weighted MRI and connectome from diffusion weighted imaging (DWI). We also investigate the association between age prediction and cognition, and study the influence of gender on prediction accuracy. Experimental results demonstrate the usefulness of NDPL for modeling brain development.


Assuntos
Encéfalo/crescimento & desenvolvimento , Córtex Cerebral/crescimento & desenvolvimento , Imageamento por Ressonância Magnética/métodos , Modelos Teóricos , Neuroimagem/métodos , Adolescente , Adulto , Fatores Etários , Encéfalo/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Criança , Pré-Escolar , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Masculino , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/crescimento & desenvolvimento , Fatores Sexuais , Adulto Jovem
6.
Biochem Biophys Res Commun ; 524(4): 1057-1063, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32067740

RESUMO

Adherens junction-associated protein-1 (AJAP1), also called SHREW1, was first discovered as a novel component of adherens junctions in 2004. In later studies, AJAP1 was found to suppress invasion and predict recurrence of some tumors. Apart from its function as a putative tumor suppressor, AJAP1 is still poorly understood. Schwenk et al. recently found that AJAP1 was tightly associated with the γ-Aminobutyric acid type B receptor subunit 1(GABABR1). It is well known that GABABR plays a vital role in epilepsy as an inhibitory transmitter receptor. Structurally adjacent, possibly functionally interacting, therefore, we hypothesize that AJAP1 participates in the onset and progression of epilepsy. We designed this experiment to investigate the expression and location of AJAP1 in temporal lobe epilepsy (TLE) patients and kainic acid(KA)-induced epilepsy animal models by immunofluorescence and Western blot analyses. We overexpressed and inhibited AJAP1 through lentiviruses in KA-induced models and observed the corresponding effects on epileptic animals. Double-label immunofluorescence showed that AJAP1 was expressed mainly in neurons. Western blot analysis revealed that AJAP1 expression was downregulated in the neocortex of TLE patients and the hippocampus and neocortex of epileptic animal models. The overexpression of AJAP1 can reduce the frequency of spontaneous seizures, whereas the inhibition of AJAP1 expression can increase the incidence rate. Our study demonstrated that AJAP1 may be involved in the pathogenic process of epilepsy and may represent a novel antiepileptic target.


Assuntos
Epilepsia/metabolismo , Receptores de GABA-B/metabolismo , Adolescente , Adulto , Animais , Comportamento Animal , Encéfalo/metabolismo , Encéfalo/patologia , Moléculas de Adesão Celular/análise , Moléculas de Adesão Celular/metabolismo , Criança , Epilepsia/patologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Receptores de GABA-B/análise , Adulto Jovem
7.
Biochemistry ; 58(38): 3955-3959, 2019 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-31468963

RESUMO

Guanine (G) quadruplexes (G4s) can be formed by G-rich sequences when stabilized by the binding of cations (typically K+ or Na+) and play an essential role in replication, recombination, transcription, and telomere maintenance. Understanding of the G4 folding process is crucial for determining their cellular functions. However, G4-K+ interactions and folding pathways are still not well understood. By using human telomeric G4 (hTG4) as an example, two binding states corresponding to two K+ cations binding to hTG4 were distinguished clearly and fitted precisely. The basic binding parameters during G4-K+ interactions were measured and calculated by taking advantage of microscale thermophoresis (MST), which monitors the changes in charge and size at the same time. The G-hairpin and G-triplex have been suggested as intermediates during G4 folding and unfolding. We further analyzed the equilibrium dissociation constants of 10 possible folding intermediates using MST; thus, the energetically favorable folding/unfolding pathways were proposed. The results might not only shed new light on G4-K+ interactions and G4 folding pathways but also provide an example for experimentally studying DNA-ion interactions.


Assuntos
DNA/química , Quadruplex G , Potássio/química , Telômero/química , Cátions Monovalentes/química , Dicroísmo Circular , Fluoresceínas/química , Corantes Fluorescentes/química , Humanos , Cinética , Oligonucleotídeos/química , Coloração e Rotulagem , Termodinâmica
8.
Mikrochim Acta ; 186(4): 264, 2019 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-30929090

RESUMO

The presented voltammetric mercury(II) sensor is based on the specific interaction between Hg(II) ion and thymine-thymine base pairs. Reduced graphene oxide is functionalized with gold nanorods and then loaded with thionine and streptavidin (RGO@AuNR-TH-SA). A T-rich thiolated DNA (S1) is firstly immobilized on a gold electrode. In the presence of Hg (II), the T-rich biotin-DNA (biotin-S2) binds to S1 via T-Hg(II)-T interaction. Then, the RGO@AuNR-TH-SA is linked to the gold electrode by specific binding between SA and biotin-S2. This produces an electrochemical signal (at -0.208 V vs. Ag/AgCl) of TH that depends on the concentration of Hg (II). The peak current increases linearly in the 1 to 200 nM Hg (II) concentration range, and the detection limit is 0.24 nM. The sensor is highly selective for Hg (II) over other environmentally relevant metal ions, even at concentration ratios of >1000. Graphical abstract Schematic representation of a voltammetric biosensor for mercury(II) using reduced graphene oxide@gold nanorods (RGO@AuNRs) and thymine-Hg(II)-thymine interaction. It is based on the fact that RGO@AuNR can strongly adsorb thionine (TH) and streptavidin to realize the signal amplification.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Grafite/química , Mercúrio/análise , Nanotubos/química , Timina/química , Pareamento de Bases , DNA/genética , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Fenotiazinas/química , Reprodutibilidade dos Testes , Estreptavidina/química , Poluentes Químicos da Água/análise
9.
Photosynth Res ; 123(1): 33-43, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25227996

RESUMO

This study identifies Salsola laricifolia as a C3-C4 intermediate in tribe Salsoleae s.l., Chenopodiaceae, and compares S. laricifolia with the previously described C3-C4 intermediates in Salsoleae. Photosynthetic pathway characteristics were studied in four species of this tribe including S. laricifolia, C3 Sympegma regelii, C3-C4 S. arbusculiformis, and C4 S. arbuscula, using the approaches of leaf anatomy and ultrastructure, activities of ribulose 1-5-bisphosphate carboxylase/oxygenase (Rubisco) and PEP carboxylase (PEPC), CO2 compensation point, and immunolocalization of Rubisco, PEPC, and the P-subunit of glycine decarboxylase (GDC). Salsola laricifolia has intermediate features, with near continuous and distinctive Kranz-like cells (KLCs) compared with the C3-Sympegmoid anatomical type and the C3-C4 intermediate S. arbusculiformis, a relatively low CO2 compensation point (30.4 µmol mol(-1)) and mesophyll (M)-to KLC tissue ratio, mitochondria in KLCs primarily occurring along the centripetal wall, and specific localization of P-protein GDC in the KLCs. The C3-type isotope value (-22.4 ‰), the absence of the clear labeling for PEPC in M cells, and the low activity of the PEPC enzyme (61.5 µmol mg(-1 )chlorophyll(-1) h(-1)) support the identification of S. laricifolia as a type I C3-C4 intermediate. Although these C3-C4 intermediate species have different structural features, one with discontinuous KL cells and the other with continuous, they have similar characteristics in physiology and biochemistry.


Assuntos
Carbono/metabolismo , Fotossíntese/fisiologia , Salsola/classificação , Salsola/fisiologia , Dióxido de Carbono , Isótopos de Carbono , Glicina Desidrogenase (Descarboxilante)/metabolismo , Folhas de Planta , Proteínas Serina-Treonina Quinases/metabolismo , Transporte Proteico , Ribulose-Bifosfato Carboxilase/metabolismo , Especificidade da Espécie
10.
J Hered ; 106(2): 184-95, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25516612

RESUMO

Climatic fluctuations during the Pleistocene are usually considered as a significant factor in shaping intraspecific genetic variation and influencing demographic histories. To well-understand these processes in desert northwest China, we selected arid adapted Atraphaxis frutescens as the study species. Two cpDNA regions (psbK-psbI, psbB-psbH) were sequenced in 272 individuals from 33 natural populations across the range of this shrub, and 10 haplotypes were identified. It was found to contain high levels of total gene diversity (H T = 0.858), and low levels of within-population diversity (H S = 0.092). Analysis of molecular variance (AMOVA) indicates that genetic differentiation primarily occurs among groups of populations. Based on BEAST (Bayesian Evolutionary Analysis Sampling Trees) analysis, we suggest that intraspecific differentiation of the species, resulting from isolated populations, accompanied enhanced desertification during the middle and late Pleistocene. The expansion of the Gurbantunggut and Kumtag deserts in this area appears to have triggered divergence among populations of the western, central, and eastern portions of the region and shaped genetic differentiation among them. Two possible independent glacial refugia were predicted, the Ili Valley and the northern Junggar Basin. Extensive development of arid habitats (desert margin and arid piedmont grassland) coupled with a more equable climate because the early Holocene are factors likely to have generated recent expansion of A. frutescens.


Assuntos
Evolução Biológica , Genética Populacional , Polygonaceae/genética , Teorema de Bayes , China , Mudança Climática , DNA de Cloroplastos/genética , DNA de Plantas/genética , Variação Genética , Haplótipos , Filogeografia , Análise de Sequência de DNA
11.
J Plant Res ; 128(2): 269-82, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25626403

RESUMO

Zygophyllum xanthoxylon, a desert species, displaying a broad east-west continuous distribution pattern in arid Northwestern China, can be considered as a model species to investigate the biogeographical history of this region. We sequenced two chloroplast DNA spacers (psbK-psbI and rpl32-trnL) in 226 individuals from 31 populations to explore the phylogeographical structure. Median-joining network was constructed and analysis of AMOVA, SMOVA, neutrality tests and distribution analysis were used to examine genetic structure and potential range expansion. Using species distribution modeling, the geographical distribution of Z. xanthoxylon was modeled during the present and at the Last Glacial Maximum (LGM). Among 26 haplotypes, one was widely distributed, but most was restricted to either the eastern or western region. The populations with the highest levels of haplotype diversity were found in the Tianshan Mountains and its surroundings in the west, and the Helan Mountains and Alxa Plateau in the east. AMOVA and SAMOVA showed that over all populations, the species lacks phylogeographical structure, which is speculated to be the result of its specific biology. Neutrality tests and mismatch distribution analysis support past range expansions of the species. Comparing the current distribution to those cold and dry conditions in LGM, Z. xanthoxylon had a shrunken and more fragmented range during LGM. Based on the evidences from phylogeographical patterns, distribution of genetic variability, and paleodistribution modeling, Z. xanthoxylon is speculated most likely to have originated from the east and migrated westward via the Hexi Corridor.


Assuntos
DNA de Cloroplastos/genética , Variação Genética , Dispersão Vegetal , Zygophyllum/fisiologia , China , Ecossistema , Evolução Molecular , Haplótipos , Dados de Sequência Molecular , Filogeografia , Análise de Sequência de DNA , Zygophyllum/genética
12.
Tumour Biol ; 35(12): 12627-33, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25227662

RESUMO

It has been suggested that hOGG1 Ser326Cys polymorphism may be a risk factor for colorectal cancer. Published data on its association with colorectal cancer generated contradictory results; thus, we performed an updated meta-analysis of eligible published studies to estimate the effect of hOGG1 Ser326Cys polymorphism on colorectal cancer susceptibility. We reviewed many abstracts and finally included 18 eligible case-control studies comprising 5235 cases and 8438 controls. We pooled data with a fixed or random-effect model. Subgroup analysis by ethnicity was also performed. The overall data indicated a significant association of hOGG1 Ser326Cys polymorphism on colorectal cancer risk (allele model OR = 1.14, 95 %CI 1.02-1.27; homozygote model OR = 1.32, 95 %CI 0.92-1.92; recessive model OR = 1.12, 95 %CI 1.00-1.26; dominant model OR = 1.15, 95 %CI 1.00-1.32). Furthermore, in the subgroup analysis by ethnicity, increased cancer risk was observed among Caucasians under the allele, heterogeneity, recessive, and dominant models (allele model OR = 1.23, 95 %CI = 1.05-1.44; homozygote model OR = 1.49, 95%CI 1.05-2.12; recessive model OR = 1.40, 95 %CI 1.16-1.69; dominant model OR = 1.21, 95 %CI = 1.12-1.45). In summary, the present meta-analysis suggested that hOGG1 Ser326Cys polymorphism might modify the susceptibility to colorectal cancer among the total population, especially among Caucasians.


Assuntos
Neoplasias Colorretais/genética , DNA Glicosilases/genética , Predisposição Genética para Doença , Polimorfismo Genético , Substituição de Aminoácidos , Estudos de Casos e Controles , Códon , Humanos , Razão de Chances , Viés de Publicação , Grupos Raciais/genética , Risco
13.
J Integr Plant Biol ; 56(12): 1125-35, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24920460

RESUMO

Atraphaxis has approximately 25 species and a distribution center in Central Asia. It has been previously used to hypothesize an origin from montane forest. We sampled 18 species covering three sections within the genus and sequenced five cpDNA spacers, atpB-rbcL, psbK-psbI, psbA-trnH, rbcL, and trnL-trnF. BEAST was used to reconstruct phylogenetic relationship and time divergences, and S-DIVA and Lagrange were used, based on distribution area and ecotype data, for reconstruction of ancestral areas and events. Our results appear compatible with designation of three taxonomic sections within the genus. The generic stem and crown ages were Eocene, approximately 47 Ma, and Oligocene 27 Ma, respectively. The origin of Atraphaxis is confirmed as montane, with an ancestral area consisting of the Junggar Basin and uplands of the Pamir-Tianshan-Alatau-Altai mountain chains, and ancestral ecotype of montane forest. Two remarkable paleogeographic events, shrinkage of the inland Paratethys Sea at the boundary of the late Oligocene and early Miocene, and the time intervals of cooling and drying of global climate from 24 (22) Ma onward likely facilitated early diversification of Atraphaxis, while rapid uplift of the Tianshan Mountains during the late Miocene may have promoted later diversification.


Assuntos
DNA de Cloroplastos/genética , Filogenia , Polygonaceae/classificação , Polygonaceae/genética
14.
Adv Sci (Weinh) ; 11(19): e2308338, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38447188

RESUMO

Liquid‒liquid phase separation (LLPS) is a ubiquitous process in which proteins, RNA, and biomolecules assemble into membrane-less compartments, playing important roles in many biological functions and diseases. The current knowledge on the biophysical and biochemical principles of LLPS is largely from in vitro studies; however, the physiological environment in living cells is complex and not at equilibrium. The characteristics of intracellular dynamics and their roles in physiological LLPS remain to be resolved. Here, by using single-particle tracking of quantum dots and dynamic monitoring of the formation of stress granules (SGs) in single cells, the spatiotemporal dynamics of intracellular transport in cells undergoing LLPS are quantified. It is shown that intracellular diffusion and active transport are both reduced. Furthermore, the formation of SG droplets contributes to increased spatial heterogeneity within the cell. More importantly, the study demonstrated that the LLPS of SGs can be regulated by intracellular dynamics in two stages: the reduced intracellular diffusion promotes SG assembly and the microtubule-associated transport facilitates SG coalescences. The work on intracellular dynamics not only improves the understanding of the mechanism of physiology phase separations occurring in nonequilibrium environments but also reveals an interplay between intracellular dynamics and LLPS.


Assuntos
Pontos Quânticos , Humanos , Pontos Quânticos/metabolismo , Transporte Biológico/fisiologia , Grânulos de Estresse/metabolismo , Separação de Fases
15.
Mol Phylogenet Evol ; 68(3): 398-409, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23629053

RESUMO

Lagochilus occurs in the arid zones across temperate steppe and desert regions of Northwest China. Cooling with strong dessication in the Pleistocene, along with rapid uplift of mountain ranges peripheral to the Qinghai-Tibet Plateau, appear to have had major impacts on the genetic structure of the flora. To understand the evolutionary history of Lagochilus and the divergence related to these past shifts of habitats among these regions, we sequenced the plastid intergenic spacers, psbA-trnH and trnS-trnG from populations throughout the known distributions of ten species of the genus. We investigated species-level phylogeographical patterns within Lagochilus. Phylogenetic trees were constructed using Neighbor-joining and Bayesian inference. The divergence times of major lineages were estimated with BEAST and IMa. Genetic structure and demographic history were inferred by AMOVA, neutrality tests, mismatch distribution, and Bayesian skyline plot analyses. The results showed that most chloroplast haplotypes were species-specific, and that the phylogeny of Lagochilus is geographically structured. The estimated Bayesian chronology and IMa suggested that the main divergence events for species between major eastern and western portions of the Chinese desert occurred at the Plio-/Pleistocene boundary (ca. 2.1-2.8 Ma ago), and likely coinciding with the formation of these deserts in Northwest China. The regional demographic expansions, in the western region at ca. 0.39 Ma, and in the eastern at ca. 0.06 Ma, or across all regions at ca. 0.26 Ma, showed the response to aridification accompanied by cooling of the Pleistocene sharply increased aridity in the Chinese deserts, which reflects a major influence of geologic and climatic events on the evolution of species of Lagochilus. We suggest that diversification is most likely the result of the past fragmentation due to aridification; the expansion of the range of species along with the deserts was an adaptation to dry and cold environments during the Quaternary.


Assuntos
Biodiversidade , Lamiaceae/classificação , Lamiaceae/genética , China , DNA de Plantas , Evolução Molecular , Genes de Plantas , Variação Genética , Genética Populacional , Haplótipos , Dados de Sequência Molecular , Filogenia , Filogeografia , Análise de Sequência de DNA
16.
J Environ Radioact ; 261: 107143, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36878053

RESUMO

Anthropogenic radionuclides deposited in sediments have been used for environmental radiation risk valuation as well as source identification. In this study, we investigated the vertical distribution of plutonium (Pu) isotopes and 240Pu/239Pu atom ratios in both floodplain and lacustrine sediments in Poyang Lake. The 239+240Pu activity concentrations in floodplain sediment cores were found to range from 0.002 to 0.085 Bq kg-1, with a maximum value at the subsurface layer. The activity in lacustrine sediment cores was from 0.062 to 0.351 Bq kg-1 with a mean of 0.138 ± 0.053 Bq kg-1. The inventory of 43.15 Bq m-2 in lacustrine sediment core is comparable to the average value of global fallout expected at the same latitude. The average 240Pu/239Pu atomic ratios (0.183 ± 0.032) for sediment cores indicated that the global fallout is the major source of Pu in the studied region. The results are of great significance to the further understanding of sources, records, and environmental impacts of regional nuclear activities in the environment.


Assuntos
Sedimentos Geológicos , Lagos , Plutônio , Monitoramento de Radiação , Cinza Radioativa , Poluentes Radioativos da Água , China , Sedimentos Geológicos/análise , Lagos/análise , Plutônio/análise , Monitoramento de Radiação/métodos , Cinza Radioativa/análise , Poluentes Radioativos da Água/análise , Radioisótopos/análise
17.
Environ Sci Pollut Res Int ; 30(17): 51206-51216, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36809627

RESUMO

To clarify the impact of human activities on the natural environment, as well as the current ecological risks to the environment surrounding Zhushan Bay in Taihu Lake, the characteristics of deposited organic materials, including elements and 16 polycyclic aromatic hydrocarbons (∑16PAHs), in a sediment core from Taihu Lake were determined. The nitrogen (N), carbon (C), hydrogen (H), and sulfur (S) contents ranged from 0.08 to 0.3%, 0.83 to 3.6%, 0.63 to 1.12%, and 0.02 to 0.24%, respectively. The most abundant element in the core was C followed by H, S, and N, while elemental C and the C/H ratio displayed a decreasing trend with depth. The ∑16PAH concentration was in the range of 1807.48-4674.83 ng g-1, showing a downward trend with depth, with some fluctuations. Three-ring PAHs dominated in surface sediment, while 5-ring PAHs dominated at a depth of 55-93 cm. Six-ring PAHs appeared in the 1830s and gradually increased over time before slowly decreasing from 2005 onward due to the establishment of environmental protection measures. The ratio of PAH monomers indicated that PAHs in samples from a depth of 0 to 55 cm were mainly derived from the combustion of liquid fossil fuels, while the PAHs in the deeper samples mainly originated from petroleum. The results of a principal component analysis (PCA) showed that the PAHs in the sediment core of Taihu Lake were mainly derived from the combustion of fossil fuels, such as diesel, petroleum, gasoline, and coal. The contributions of biomass combustion, liquid fossil fuel combustion, coal combustion, and unknown source were 8.99%, 52.68%, 1.65%, and 36.68%, respectively. The results of a toxicity analysis indicated that most of the PAH monomers had little impact on the ecology, and the annual increase of a small number of monomers might have toxic effects on the biological community, resulting in a serious ecological risks, that requires the imposition of control measures.


Assuntos
Poluentes Ambientais , Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Humanos , Poluentes Ambientais/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , China , Combustíveis Fósseis/análise , Petróleo/análise , Carvão Mineral/análise , Medição de Risco , Hidrocarbonetos Policíclicos Aromáticos/análise , Lagos/análise
18.
Materials (Basel) ; 16(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36614735

RESUMO

Aluminum matrix composites have been widely used in aerospace and automotive fields due to their excellent physical properties. Cryogenic treatment was successfully adopted to improve the performance of aluminum alloy components, while its effect and mechanism on the aluminum matrix composite remained unclear. In this work, the effects of cryogenic treatment on the microstructure evolution and mechanical properties of 15%SiCp/2009 aluminum matrix composites were systematically investigated by means of Thermoelectric Power (TEP), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results showed that TEP measurement can be an effective method for evaluating the precipitation characteristics of 15%SiCp/2009 aluminum matrix composites during aging. The addition of cryogenic treatment after solution and before aging treatment promoted the precipitation from the beginning stage of aging. Furthermore, the aging time for the maximum precipitation of the θ″ phase was about 4 h advanced, as the conduction of cryogenic treatment accelerates the aging kinetics. This was attributed to the great difference in the linear expansion coefficient between the aluminum alloy matrix and SiC-reinforced particles, which could induce high internal stress in their boundaries for precipitation. Moreover, the lattice contraction of the aluminum alloy matrix during cryogenic treatment led to the increase in dislocation density and micro defects near the boundaries, thus providing more nucleation sites for precipitation during the aging treatment. After undergoing artificial aging treatment for 20 h, the increase in dispersive, distributed precipitates after cryogenic treatment improved the hardness and yield strength by 4% and 16 MPa, respectively.

19.
J Hazard Mater ; 445: 130474, 2023 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-36446312

RESUMO

The upper reaches of the Yangtze River have experienced increasing anthropogenic stress. Quantitative tracing of carbon (C) sources and ecological risks through biomarkers i.e., polycyclic aromatic hydrocarbons (PAHs) and n-alkanes is significant for C neutrality and sequestration. Here, source and sink patterns, and factors influencing C burial and biomarker components in a small catchment of Dianchi Lake were explored. The sediment core covered the period 1855-2019. Before 1945, the organic C accumulation rate (OCAR) ranged from 0.71 to 5.12 mg cm-2 yr-1, and the PAHs and n-alkanes fluxes were 106.99-616.09 ng cm-2 yr-1 and 5.56-31.37 µg cm-2 yr-1. During 1945-2005, the OCAR, PAH, and n-alkane burial rapidly increased from 3.19 to 16.17 mg cm-2 yr-1, 230.40 to 2538.81 ng cm-2 yr-1, and 11.63 to 61.90 µg cm-2 yr-1. During 1855-2019, deposition fluxes of PAHs and n-alkanes increased 13.01 and 9.14 times, resulting in increased C burial, driven by environmental changes. A PMF model and the diagnostic ratio indicated that PAHs from coal combustion and traffic emission increased from 22.32% to 65.20% during 1855-2019. The PAH concentrations reflected normal-moderate contamination and potential risks to the aquatic environment. The results facilitate a comprehensive understanding of anthropogenic-driven interactions between increasing OC burial and ecological risks.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Carbono/análise , Poluentes Químicos da Água/análise , Sedimentos Geológicos , Monitoramento Ambiental/métodos , Alcanos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Lagos , China
20.
Front Hum Neurosci ; 17: 1257987, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38077182

RESUMO

Introduction: Autism Spectrum Disorder (ASD) has a significant impact on the health of patients, and early diagnosis and treatment are essential to improve their quality of life. Machine learning methods, including multi-classifier fusion, have been widely used for disease diagnosis and prediction with remarkable results. However, current multi-classifier fusion methods lack the ability to measure the belief level of different samples and effectively fuse them jointly. Methods: To address these issues, a multi-classifier fusion classification framework based on belief-value for ASD diagnosis is proposed in this paper. The belief-value measures the belief level of different samples based on distance information (the output distance of the classifier) and local density information (the weight of the nearest neighbor samples on the test samples), which is more representative than using a single type of information. Then, the complementary relationships between belief-values are captured via a multilayer perceptron (MLP) network for effective fusion of belief-values. Results: The experimental results demonstrate that the proposed classification framework achieves better performance than a single classifier and confirm that the fusion method used can effectively fuse complementary relationships to achieve accurate diagnosis. Discussion: Furthermore, the effectiveness of our method has only been validated in the diagnosis of ASD. For future work, we plan to extend this method to the diagnosis of other neuropsychiatric disorders.

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