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1.
Science ; 385(6704): 80-86, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38963846

RESUMO

Classical migraine patients experience aura, which is transient neurological deficits associated with cortical spreading depression (CSD), preceding headache attacks. It is not currently understood how a pathological event in cortex can affect peripheral sensory neurons. In this study, we show that cerebrospinal fluid (CSF) flows into the trigeminal ganglion, establishing nonsynaptic signaling between brain and trigeminal cells. After CSD, ~11% of the CSF proteome is altered, with up-regulation of proteins that directly activate receptors in the trigeminal ganglion. CSF collected from animals exposed to CSD activates trigeminal neurons in naïve mice in part by CSF-borne calcitonin gene-related peptide (CGRP). We identify a communication pathway between the central and peripheral nervous system that might explain the relationship between migrainous aura and headache.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina , Depressão Alastrante da Atividade Elétrica Cortical , Transtornos de Enxaqueca , Gânglio Trigeminal , Animais , Camundongos , Peptídeo Relacionado com Gene de Calcitonina/líquido cefalorraquidiano , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Líquido Cefalorraquidiano/metabolismo , Modelos Animais de Doenças , Transtornos de Enxaqueca/líquido cefalorraquidiano , Transtornos de Enxaqueca/metabolismo , Transtornos de Enxaqueca/fisiopatologia , Proteoma/metabolismo , Transdução de Sinais , Gânglio Trigeminal/metabolismo , Gânglio Trigeminal/fisiopatologia
2.
Brain ; 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39028640

RESUMO

Huntington's disease and juvenile-onset schizophrenia have long been regarded as distinct disorders. However, both manifest cell-intrinsic abnormalities in glial differentiation, with resultant astrocytic dysfunction and hypomyelination. To assess whether a common mechanism might underlie the similar glial pathology of these otherwise disparate conditions, we used comparative correlation network approaches to analyse RNA-sequencing data from human glial progenitor cells (hGPCs) produced from disease-derived pluripotent stem cells. We identified gene sets preserved between Huntington's disease and schizophrenia hGPCs yet distinct from normal controls that included 174 highly connected genes in the shared disease-associated network, focusing on genes involved in synaptic signalling. These synaptic genes were largely suppressed in both schizophrenia and Huntington's disease hGPCs, and gene regulatory network analysis identified a core set of upstream regulators of this network, of which OLIG2 and TCF7L2 were prominent. Among their downstream targets, ADGRL3, a modulator of glutamatergic synapses, was notably suppressed in both schizophrenia and Huntington's disease hGPCs. Chromatin immunoprecipitation sequencing confirmed that OLIG2 and TCF7L2 each bound to the regulatory region of ADGRL3, whose expression was then rescued by lentiviral overexpression of these transcription factors. These data suggest that the disease-associated suppression of OLIG2 and TCF7L2-dependent transcription of glutamate signalling regulators may impair glial receptivity to neuronal glutamate. The consequent loss of activity-dependent mobilization of hGPCs may yield deficient oligodendrocyte production, and hence the hypomyelination noted in these disorders, as well as the disrupted astrocytic differentiation and attendant synaptic dysfunction associated with each. Together, these data highlight the importance of convergent glial molecular pathology in both the pathogenesis and phenotypic similarities of two otherwise unrelated disorders, Huntington's disease and schizophrenia.

3.
Nat Commun ; 15(1): 3873, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719882

RESUMO

Human glial progenitor cells (hGPCs) exhibit diminished expansion competence with age, as well as after recurrent demyelination. Using RNA-sequencing to compare the gene expression of fetal and adult hGPCs, we identify age-related changes in transcription consistent with the repression of genes enabling mitotic expansion, concurrent with the onset of aging-associated transcriptional programs. Adult hGPCs develop a repressive transcription factor network centered on MYC, and regulated by ZNF274, MAX, IKZF3, and E2F6. Individual over-expression of these factors in iPSC-derived hGPCs lead to a loss of proliferative gene expression and an induction of mitotic senescence, replicating the transcriptional changes incurred during glial aging. miRNA profiling identifies the appearance of an adult-selective miRNA signature, imposing further constraints on the expansion competence of aged GPCs. hGPC aging is thus associated with acquisition of a MYC-repressive environment, suggesting that suppression of these repressors of glial expansion may permit the rejuvenation of aged hGPCs.


Assuntos
Envelhecimento , MicroRNAs , Neuroglia , Fatores de Transcrição , Humanos , Neuroglia/metabolismo , Neuroglia/citologia , Envelhecimento/genética , Envelhecimento/metabolismo , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , MicroRNAs/genética , MicroRNAs/metabolismo , Senescência Celular/genética , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco/metabolismo , Células-Tronco/citologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Adulto , Redes Reguladoras de Genes , Proliferação de Células/genética , Regulação da Expressão Gênica no Desenvolvimento , Perfilação da Expressão Gênica
4.
Heliyon ; 10(7): e27900, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38571664

RESUMO

Cardiovascular (CVD) + Respiratory diseases are recognized as the main cause of death worldwide. Fluctuations in temperature and air pollution have been reported as one of the most important causes of cardiovascular & respiratory diseases. Therefore, in the current study, we assessed the relationship between ambient air temperature and pollution on the number of total emergency hospital admission due to cardiovascular and respiratory conditions in the City of Bojnord, northeastern Iran. The meteorological data, including daily temperature, relative humidity and concentrations of five air pollutants CO, NO2, NOX SO2, and PM10 were obtained from online electronic sensors at the Bojnurd meteorological station from 21th March 2018 to 20th March 2020. Statistical analysis, penalized distributed lag non-linear method was applied using R Software. Also, sensitivity analysis test was calculated by using appropriate application. The results of the study revealed that the effect of higher and lower temperatures was observed immediately from the first day and the second week, respectively. Also result showed with increase and decrease temperature, significantly increased the risk of hospitalization by 36% (RR, 1.36; 95% CI (1), 0.95 to 1.95) and 17% (RR, 1.17; 95% CI (1), 0.88 to 1.55) until the lag 25th day, respectively. Based on the results, increasing temperature significantly increased the hospitalization rate of cardiopulmonary patients, but the effect of cold was not significant on the population as well as age and gender subgroups. Study have also proved that there is no significance correlation between air pollutant and Cardiovascular & respiratory diseases.

5.
Phys Rev Lett ; 132(15): 155101, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38682996

RESUMO

The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially and temporally coincident with the plasma neutron source. An optical Thomson scattering apparatus designed for the FuZE device measures temperatures in the range of 1-3 keV on the axis of the device, 20 cm downstream of the nose cone. The 17-fiber system measures the radial profiles of the electron temperature. Scanning the laser time with respect to the neutron pulse time over a series of discharges allows the reconstruction of the T_{e} temporal response, confirming that the electron temperature peaks simultaneously with the neutron output, as well as the pinch current and inductive voltage generated within the plasma. Comparison to spectroscopic ion temperature measurements suggests a plasma in thermal equilibrium. The elevated T_{e} confirms the presence of a plasma assembled on axis, and indicates limited radiative losses, demonstrating a basis for scaling this device toward net gain fusion conditions.

7.
Emerg Infect Dis ; 30(3): 499-509, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38407176

RESUMO

We characterized the spatial distribution of drug-susceptible (DS) and multidrug-resistant (MDR) tuberculosis (TB) cases in Ho Chi Minh City, Vietnam, a major metropolis in southeastern Asia, and explored demographic and socioeconomic factors associated with local TB burden. Hot spots of DS and MDR TB incidence were observed in the central parts of Ho Chi Minh City, and substantial heterogeneity was observed across wards. Positive spatial autocorrelation was observed for both DS TB and MDR TB. Ward-level TB incidence was associated with HIV prevalence and the male proportion of the population. No ward-level demographic and socioeconomic indicators were associated with MDR TB case count relative to total TB case count. Our findings might inform spatially targeted TB control strategies and provide insights for generating hypotheses about the nature of the relationship between DS and MDR TB in Ho Chi Minh City and the wider southeastern region of Asia.


Assuntos
Tuberculose Resistente a Múltiplos Medicamentos , Tuberculose , Masculino , Humanos , Vietnã/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Ásia , Análise Espacial
8.
RSC Adv ; 14(7): 4966-4974, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38327810

RESUMO

The auxetic materials have exotic mechanical properties compared to conventional materials, such as higher indentation resistance, more superior sound absorption performance. Although the auxetic behavior has also been observed in two-dimensional (2D) nanomaterials, to date there has not been much research on auxetic materials in the vertical asymmetric Janus 2D layered structures. In this paper, we explore the mechanical, electronic, and transport characteristics of Janus Si2OX (X = S, Se, Te) monolayers by first-principle calculations. Except for the Si2OTe monolayer, both Si2OS and Si2OSe are found to be stable. Most importantly, both Si2OS and Si2OSe monolayers are predicted to be auxetic semiconductors with a large negative Poisson's ratio. The auxetic behavior is clearly observed in the Janus Si2OS monolayer with an extremely large negative Poisson's ratio of -0.234 in the x axis. At the equilibrium state, both Si2OS and Si2OSe materials exhibit indirect semiconducting characteristics and their band gaps can be easily altered by the mechanical strain. More interestingly, the indirect-direct bandgap phase transitions are observed in both Si2OS and Si2OSe monolayers when the biaxial strains are introduced. Further, the studied Janus structures also exhibit remarkably high electron mobility, particularly along the x direction. Our findings demonstrate that Si2OS and Si2OSe monolayers are new auxetic materials with asymmetric structures and show their great promise in electronic and nanomechanical applications.

9.
Sci Rep ; 13(1): 18971, 2023 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-37923921

RESUMO

This study quantifies the groundwater fluoride contamination and assesses associated health risks in fluoride-prone areas of the city of Taj Mahal, Agra, India. The United States Environmental Protection Agency (USEPA) risk model and Monte Carlo Simulations were employed for the assessment. Result revealed that, among various rural and urban areas Pachgain Kheda exhibited the highest average fluoride concentration (5.20 mg/L), while Bagda showed the lowest (0.33 mg/L). Similarly, K.K. Nagar recorded 4.38 mg/L, and Dayalbagh had 1.35 mg/L. Both urban and rural areas exceeded the WHO-recommended limit of 1.5 mg/L, signifying significant public health implications. Health risk assessment indicated a notably elevated probability of non-carcinogenic risk from oral groundwater fluoride exposure in the rural Baroli Ahir block. Risk simulations highlighted that children faced the highest health risks, followed by teenagers and adults. Further, Monte Carlo simulation addressed uncertainties, emphasizing escalated risks for for children and teenagers. The Hazard Quotient (HQ) values for the 5th and 95th percentile in rural areas ranged from was 0.28-5.58 for children, 0.15-2.58 for teenager, and 0.05-0.58 for adults. In urban areas, from the range was 0.53 to 5.26 for children, 0.27 to 2.41 for teenagers, and 0.1 to 0.53 for adults. Physiological and exposure variations rendered children and teenagers more susceptible. According to the mathematical model, calculations for the non-cancerous risk of drinking water (HQ-ing), the most significant parameters in all the targeted groups of rural areas were concentration (CW) and Ingestion rate (IR). These findings hold relevance for policymakers and regulatory boards in understanding the actual impact and setting pre-remediation goals.


Assuntos
Água Potável , Água Subterrânea , Poluentes Químicos da Água , Criança , Adulto , Adolescente , Humanos , Fluoretos/efeitos adversos , Fluoretos/análise , Método de Monte Carlo , Poluentes Químicos da Água/análise , Água Potável/análise , Índia , Medição de Risco , Monitoramento Ambiental
10.
Cell Death Discov ; 9(1): 423, 2023 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-38001121

RESUMO

MicroRNAs (miRNAs) are a class of non-coding RNAs (ncRNAs) with a short length of 19-22 nucleotides. miRNAs are posttranscriptional regulators of gene expression involved in various biological processes like cell growth, apoptosis, and angiogenesis. miR-184 is a well-studied miRNA, for which most studies report its downregulation in cancer cells and tissues and experiments support its role as a tumor suppressor inhibiting malignant biological behaviors of cancer cells in vitro and in vivo. To exert its functions, miR-184 affects some signaling pathways involved in tumorigenesis like Wnt and ß-catenin, and AKT/mTORC1 pathway, oncogenic factors (e.g., c-Myc) or apoptotic proteins, such as Bcl-2. Interestingly, clinical investigations have shown miR-184 with good performance as a prognostic/diagnostic biomarker for various cancers. Additionally, exogenous miR-184 in cell and xenograft animal studies suggest it as a therapeutic anticancer target. In this review, we outline the studies that evaluated the roles of miR-184 in tumorigenesis as well as its clinical significance.

11.
Nanoscale Adv ; 5(23): 6705-6713, 2023 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-38024315

RESUMO

From the extending requirements for using innovative materials in advanced technologies, it is necessary to explore new materials for relevant applications. In this work, we design new two-dimensional (2D) Janus ZrSiSZ2 (Z = N, P, As) monolayers and investigate their crystal lattice and dynamic stability by using density functional theory investigations. The two stable structures of ZrSiSP2 and ZrSiSAs2 are then systematically examined for thermal, energetic, and mechanical stability, and electronic and transport properties. The calculation results demonstrate that both the ZrSiSP2 and ZrSiSAs2 monolayers have good thermal stability at room temperature and high energetic/mechanical stabilities for experimental synthesis. The studied structures are found to be in-direct semiconductors. Specifically, with moderate band-gap energies of 1.04 to 1.29 eV for visible light absorption, ZrSiSP2 and ZrSiSAs2 can be considered potential candidates for photovoltaic applications. The applied biaxial strains and external electric fields slightly change the band-gap energies of the monolayers. We also calculate the carrier mobilities for the transport properties based on the deformation potential method. Due to the lower effective masses, the carrier mobilities in the x direction are higher than those in the y direction. The carrier mobilities of the ZrSiSP2 and ZrSiSAs2 monolayers are anisotropic not only in transport directions but also for the electrons and holes. We believe that the results of our work may stimulate further studies to explore more new 2D Janus monolayers with novel properties of the MA2Z4 family materials.

12.
Clin Ter ; 174(5): 420-425, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37674451

RESUMO

Objective: This descriptive study aims to describe various anatomical morphological indicators of the triangular fibrocartilage complex (TFCC) in Vietnamese adults. Materials and methods: We analyzed 30 wrist joints from 15 fresh cadavers. To access the components of the TFCC, the wrist joints were dissected and measured, and anatomical morphological indices, inclu-ding length, width, thickness, origin, and insertion, were recorded. Results: Nine of 30 articular discs had central tears. The average length of the articular disc was 10.05±2.26 mm, while the average width was 12.10±1.39 mm. The average thickness of the articular disk on the ulnar side was 1.56±0.42 mm, while the average thickness of the articular disk on the radial side was 2.63±1.04 mm. Most meniscus homologues (86.6%) were of the narrow opening type according to the Ishii classification, with a horizontal dimension of 6.98±2.05 mm, anteroposterior diameter of 8.94±2.46 mm, and thickness of 1.27±0.41 mm. The volar radioulnar ligament averaged 12.75±2.17 mm in length and 2.54±0.77 mm in width, while the dorsal radioulnar ligament ave-raged 12.82±2.63 mm in length and 2.37±0.65 mm in width. The ulnar collateral ligament averaged 13.59±2.79 mm in length, 3.75±0.80 mm in width, and 0.95±0.46 mm in thickness. The ulnolunate and ulnotriquetral ligaments had average lengths of 7.34±2.87 mm and 5.70±2.98 mm, widths of 3.93±1.55 mm and 4.87±1.06 mm, and thicknesses of 0.96±0.61 mm and 1.43±0.98 mm, respectively. Conclusions: There are no differences in the shape or structure of the adult Vietnamese TFCC. No significant differences were noted in any TFCC component according to wrist side or gender.


Assuntos
Fibrocartilagem Triangular , Adulto , Humanos , Fibrocartilagem Triangular/anatomia & histologia , População do Sudeste Asiático , Articulação do Punho/anatomia & histologia , Punho , Cadáver
13.
Psychol Health ; : 1-17, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37772746

RESUMO

OBJECTIVE: Work-family conflict has been shown to adversely affect individuals' health and function, particularly among individuals with chronic pain. The current study's longitudinal serial mediation model examined whether work-to-family conflict predicted greater pain interference through higher levels of family strain and loneliness among midlife adults with chronic pain. METHODS AND MEASURES: The study consisted of 303 participants from two waves of the national longitudinal study of Midlife in the United States (MIDUS) at wave II from 2004 to 2006 (Mage = 57, SD = 11) and wave 3 from 2013 to 2014 (Mage = 66, SD = 11). Participants were employed at time 1 and had chronic pain at both time points, and 54.5% of participants identified as female. RESULTS: Family strain at time 1 (T1) and loneliness at time 2 (T2), respectively, significantly mediated the association of work-to-family conflict (T1) on pain interference at T2. Participants with greater work-to-family conflict perceived more family strain, felt lonelier, and, in turn, reported experiencing higher interference from chronic pain. CONCLUSION: Results suggest that unmanaged work-to-family conflict could be a risk factor that exacerbates chronic pain symptoms through worsening family relationships and loneliness among midlife adults with chronic pain.

14.
Nat Biotechnol ; 2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37460676

RESUMO

Competition among adult brain cells has not been extensively researched. To investigate whether healthy glia can outcompete diseased human glia in the adult forebrain, we engrafted wild-type (WT) human glial progenitor cells (hGPCs) produced from human embryonic stem cells into the striata of adult mice that had been neonatally chimerized with mutant Huntingtin (mHTT)-expressing hGPCs. The WT hGPCs outcompeted and ultimately eliminated their human Huntington's disease (HD) counterparts, repopulating the host striata with healthy glia. Single-cell RNA sequencing revealed that WT hGPCs acquired a YAP1/MYC/E2F-defined dominant competitor phenotype upon interaction with the host HD glia. WT hGPCs also outcompeted older resident isogenic WT cells that had been transplanted neonatally, suggesting that competitive success depended primarily on the relative ages of competing populations, rather than on the presence of mHTT. These data indicate that aged and diseased human glia may be broadly replaced in adult brain by younger healthy hGPCs, suggesting a therapeutic strategy for the replacement of aged and diseased human glia.

15.
Water Res X ; 19: 100177, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37008369

RESUMO

Members of the genus Tetrasphaera are putative polyphosphate accumulating organisms (PAOs) that have been found in greater abundance than Accumulibacter in many full-scale enhanced biological phosphorus removal (EBPR) wastewater treatment plants worldwide. Nevertheless, previous studies on the effect of environmental conditions, such as pH, on the performance of EBPR have focused mainly on the response of Accumulibacter to pH changes. This study examines the impact of pH on a Tetrasphaera PAO enriched culture, over a pH range from 6.0 to 8.0 under both anaerobic and aerobic conditions, to assess its impact on the stoichiometry and kinetics of Tetrasphaera metabolism. It was discovered that the rates of phosphorus (P) uptake and P release increased with an increase of pH within the tested range, while PHA production, glycogen consumption and substrate uptake rate were less sensitive to pH changes. The results suggest that Tetrasphaera PAOs display kinetic advantages at high pH levels, which is consistent with what has been observed previously for Accumulibacter PAOs. The results of this study show that pH has a substantial impact on the P release and uptake kinetics of PAOs, where the P release rate was >3 times higher and the P uptake rate was >2 times higher at pH 8.0 vs pH 6.0, respectively. Process operational strategies promoting both Tetrasphaera and Accumulibacter activity at high pH do not conflict with each other, but lead to a potentially synergistic impact that can benefit EBPR performance.

16.
Phys Chem Chem Phys ; 25(12): 8779-8788, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36912122

RESUMO

Novel Janus materials have attracted broad interest due to the outstanding properties created by their out-of-plane asymmetry, with increasing theoretical exploration and more reports of successful fabrication in recent years. Here, we construct and explore the crystal structures, stabilities, electronic band structures, and transport properties - including carrier mobilities - of two-dimensional Janus MGeSiP4 (M = Ti, Zr, or Hf) monolayers based on density functional theory calculations. From the cohesive energies, elastic constants, and phonon dispersion calculations, the monolayers are confirmed to exhibit structural stability with high feasibility for experimental synthesis. All the structures are indirect band-gap semiconductors with calculated band-gap energies in the range of 0.77 eV to 1.01 eV at the HSE06 (Heyd-Scuseria-Ernzerhof) level. Interestingly, by applying external biaxial strain, a semiconductor to metal phase transition is observed for the three Janus structures. This suggests potential for promising applications in optoelectronic and electromechanical devices. Notably, the MGeSiP4 monolayers show directionally anisotropic carrier mobility with a high electron mobility of up to 2.72 × 103 cm2 V-1 s-1 for the ZrGeSiP4 monolayer, indicating advantages for applications in electronic devices. Hence, the presented results reveal the novel properties of the 2D Janus MGeSiP4 monolayers and demonstrate their great potential applications in nanoelectronic and/or optoelectronic devices. This investigation could stimulate further theoretical and experimental studies on these excellent materials and motivate further explorations of new members of this 2D Janus family.

17.
Nanoscale Adv ; 5(7): 2102-2110, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36998644

RESUMO

The maximum efficiency of solar cells utilizing a single layer for photovoltaic conversion is given by the single junction Shockley-Queisser limit. In tandem solar cells, a stack of materials with different band gaps contribute to the conversion, enabling tandem cells to exceed the single junction Shockley-Queisser limit. An intriguing variant of this approach is to embed semiconducting nanoparticles in a transparent conducting oxide (TCO) solar cell front contact. This alternative route would enhance the functionality of the TCO layer, allowing it to participate directly in photovoltaic conversion via photon absorption and charge carrier generation in the nanoparticles. Here, we demonstrate the functionalization of ZnO through incorporation of either ZnFe2O4 spinel nanoparticles (NPs) or inversion domain boundaries (IDBs) decorated by Fe. Diffuse reflectance spectroscopy and electron energy loss spectroscopy show that samples containing spinel particles and samples containing IDBs decorated by Fe both display enhanced absorption in the visible range at around 2.0 and 2.6 eV. This striking functional similarity was attributed to the local structural similarity around Fe-ions in spinel ZnFe2O4 and at Fe-decorated basal IDBs. Hence, functional properties of the ZnFe2O4 arise already for the two-dimensional basal IDBs, from which these planar defects behave like two-dimensional spinel-like inclusions in ZnO. Cathodoluminescence spectra reveal an increased luminescence around the band edge of spinel ZnFe2O4 when measuring on the spinel ZnFe2O4 NPs embedded in ZnO, whereas spectra from Fe-decorated IDBs could be deconvoluted into luminescence contributions from bulk ZnO and bulk ZnFe2O4.

18.
Proc Natl Acad Sci U S A ; 120(1): e2210561119, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36584294

RESUMO

Brown algae annually convert gigatons of carbon dioxide into carbohydrates, including the complex extracellular matrix polysaccharide fucoidan. Due to its persistence in the environment, fucoidan is potentially a pathway for marine carbon sequestration. Rates of fucoidan secretion by brown algae remain unknown due to the challenge of identifying and quantifying complex polysaccharides in seawater. We adapted the techniques of anion exchange chromatography, enzyme-linked immunosorbent assay, and biocatalytic enzyme-based assay for detection and quantification of fucoidan. We found the brown alga Fucus vesiculosus at the Baltic Sea coast of south-west Finland to secrete 0.3% of their biomass as fucoidan per day. Dissolved fucoidan concentrations in seawater adjacent to algae reached up to 0.48 mg L-1. Fucoidan accumulated during incubations of F. vesiculosus, significantly more in light than in darkness. Maximum estimation by acid hydrolysis indicated fucoidan secretion at a rate of 28 to 40 mg C kg-1 h-1, accounting for 44 to 50% of all exuded dissolved organic carbon. Composed only of carbon, oxygen, hydrogen, and sulfur, fucoidan secretion does not consume nutrients enabling carbon sequestration independent of algal growth. Extrapolated over a year, the algae sequester more carbon into secreted fucoidan than their biomass. The global utility of fucoidan secretion is an alternative pathway for carbon dioxide removal by brown algae without the need to harvest or bury algal biomass.


Assuntos
Dióxido de Carbono , Phaeophyceae , Dióxido de Carbono/metabolismo , Polissacarídeos/metabolismo , Phaeophyceae/metabolismo , Oceanos e Mares
19.
Chem Biodivers ; 20(1): e202200843, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36574472

RESUMO

Golden Camellias have recently been used as a food, cosmetic, and traditional medicine in China and Vietnam. Forty-two species have natural distribution in Vietnam, of which thirty-two species were considered endemic species of this country. The morphology of leaves and flowers of these species were similar; therefore, their taxonomic identification usually needed experts and the authentication has often been confused among species. Our study aims to describe the genetic diversity and the relationship of six species Camellia phanii, Camellia tamdaoensis, Camellia tienii, Camellia flava, Camellia petelotii and Camellia euphlebia by using three chloroplast DNA-barcodes: matK, rbcL and trnH-psbA. We also clarified the significant differences in anatomical characteristics of midvein and blade of their leaves, which suggested the possibility to use these criteria in taxonomy. In addition, preliminary chemical profiles of the methanolic extracts of leaves from six Golden Camellias such as total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and chlorogenic acids content (TCGAs) also showed the diversity among them. Interestingly, the discrimination on the catechins profile among six species followed the same tendency with the genetic distance on the phylogeny tree suggesting that catechins (i. e., discriminative catechins) can be biomarkers for the chemotaxonomy of these six Golden Camellias.


Assuntos
Camellia , Camellia/química , Vietnã , Flavonoides/análise , Flores/química , Folhas de Planta , Código de Barras de DNA Taxonômico , Filogenia , DNA de Plantas/análise
20.
Braz J Biol ; 84: e264369, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36287528

RESUMO

Panax vietnamensis Ha et Grushv. is a precious medicinal species native to the tropical forests of Vietnam. Due to habitat loss and over-harvesting, this species is endangered in Vietnam. To conserve the species, we investigated genetic variability and population structure using nine microsatellites for 148 individuals from seven populations across the current distribution range of P. vietnamensis in Vietnam. We determined a moderate genetic diversity within populations (HO = 0.367, HE = 0.437) and relatively low population differentiation (the Weir and Cockerham index of 0.172 and the Hedrick index of 0.254) and showed significant differentiation (P < 0.05), which suggested fragmented habitats, over-utilization and over-harvesting of P. vietnamensis. Different clustering methods revealed that individuals were grouped into two major clusters, which were associated with gene flow across the geographical range of P. vietnamensis. This study also detected that ginseng populations can have undergone a recent bottleneck. We recommend measures in future P. vietnamensis conservation and breeding programs.


Assuntos
Panax , Humanos , Panax/genética , Panax/química , Vietnã , Melhoramento Vegetal , Repetições de Microssatélites/genética , Povo Asiático , Variação Genética/genética
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