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1.
Cell Discov ; 10(1): 71, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956429

RESUMO

The initiation of osteogenesis primarily occurs as mesenchymal stem cells undergo differentiation into osteoblasts. This differentiation process plays a crucial role in bone formation and homeostasis and is regulated by two intricate processes: cell signal transduction and transcriptional gene expression. Various essential cell signaling pathways, including Wnt, BMP, TGF-ß, Hedgehog, PTH, FGF, Ephrin, Notch, Hippo, and Piezo1/2, play a critical role in facilitating osteoblast differentiation, bone formation, and bone homeostasis. Key transcriptional factors in this differentiation process include Runx2, Cbfß, Runx1, Osterix, ATF4, SATB2, and TAZ/YAP. Furthermore, a diverse array of epigenetic factors also plays critical roles in osteoblast differentiation, bone formation, and homeostasis at the transcriptional level. This review provides an overview of the latest developments and current comprehension concerning the pathways of cell signaling, regulation of hormones, and transcriptional regulation of genes involved in the commitment and differentiation of osteoblast lineage, as well as in bone formation and maintenance of homeostasis. The paper also reviews epigenetic regulation of osteoblast differentiation via mechanisms, such as histone and DNA modifications. Additionally, we summarize the latest developments in osteoblast biology spurred by recent advancements in various modern technologies and bioinformatics. By synthesizing these insights into a comprehensive understanding of osteoblast differentiation, this review provides further clarification of the mechanisms underlying osteoblast lineage commitment, differentiation, and bone formation, and highlights potential new therapeutic applications for the treatment of bone diseases.

2.
Pest Manag Sci ; 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38970236

RESUMO

BACKGROUND: Grapholita molesta is an important and harmful fruit pest worldwide, with widespread feeding hosts. Trypsin, an indispensable hydrolytic digestive protease in the insect gut, is crucial in digestion, growth and development. We analyzed the characteristics of the trypsin-encoding genes, screened for the optimal dose of RNAi mediated by nanocarriers, and investigated various indices of larval growth and development of G. molesta. RESULTS: Gut content (GC) and RNase A degraded double-stranded RNA (dsRNA), with a faster degradation rate at higher concentrations. Star polycation (SPc) nanomaterials protected dsGFP from degradation by anion-cation binding and did not migrate through agarose gel. The key conserved motifs of the trypsin-encoding genes were similar, exhibiting high homology with those in other lepidopteran insects. An interference efficiency of ≈70% was achieved with SPc nanomaterial-mediated RNA interference with 0.05 µg dsRNA. The efficiency of continuous interference was stable. Trypsin activity, body weight of 8-day-old larvae, pupal weight and emergence rate were significantly reduced, and the larval stage was significantly prolonged. CONCLUSION: The investigated trypsin gene is a key target gene in the growth and development of G. molesta. We investigated the efficiency and convenience of feeding SPc nanomaterials in a functional study of insects. Our results provide valuable data for the development of efficient trypsin-targeting pesticides. © 2024 Society of Chemical Industry.

3.
Prev Med Rep ; 43: 102794, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38975281

RESUMO

Objective: Cannabis use has been linked to physical, psychological, and behavioral changes. Although research indicates separately that informal social support and formal social engagement - which are correlated measures - serve as protective factors in cannabis use, much of this research focuses on youth and more urban samples, limiting our understanding of if these findings are true for rural populations where social support and social engagement are particularly important for health and health behaviors. To fill the research gap, this study examines the effects of informal social support (tangible support and emotional support) and formal social engagement on cannabis use among rural working-age adults. Methods: This research analyzed 1,122 observations from a cross-sectional online survey conducted in 2022 of working-age adults (18-64) from rural America. Multilevel logistic regression models were used to predict cannabis use in the past 12 months using informal social support (tangible support and emotional support) and formal social engagement and other sociodemographic covariates and state legalization status. Results: Multilevel logistic modeling indicates that low emotional support and low formal social engagement are associated with a higher odds of reporting cannabis use in the past 12 months among rural working-age adults, net of other sociodemographic variables and state legalization status. Conclusions: The study suggests that emotional support and social engagement may contribute to cannabis use prevention among rural working-age adults. These findings should inform future research as well as the development of tailored health interventions targeting rural working-age adults.

4.
Bone Res ; 12(1): 39, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38987555

RESUMO

Wnts are secreted, lipid-modified proteins that bind to different receptors on the cell surface to activate canonical or non-canonical Wnt signaling pathways, which control various biological processes throughout embryonic development and adult life. Aberrant Wnt signaling pathway underlies a wide range of human disease pathogeneses. In this review, we provide an update of Wnt/ß-catenin signaling components and mechanisms in bone formation, homeostasis, and diseases. The Wnt proteins, receptors, activators, inhibitors, and the crosstalk of Wnt signaling pathways with other signaling pathways are summarized and discussed. We mainly review Wnt signaling functions in bone formation, homeostasis, and related diseases, and summarize mouse models carrying genetic modifications of Wnt signaling components. Moreover, the therapeutic strategies for treating bone diseases by targeting Wnt signaling, including the extracellular molecules, cytosol components, and nuclear components of Wnt signaling are reviewed. In summary, this paper reviews our current understanding of the mechanisms by which Wnt signaling regulates bone formation, homeostasis, and the efforts targeting Wnt signaling for treating bone diseases. Finally, the paper evaluates the important questions in Wnt signaling to be further explored based on the progress of new biological analytical technologies.


Assuntos
Doenças Ósseas , Homeostase , Osteogênese , Via de Sinalização Wnt , Humanos , Animais , Osteogênese/fisiologia , Doenças Ósseas/metabolismo , Doenças Ósseas/terapia , beta Catenina/metabolismo , Proteínas Wnt/metabolismo
6.
Nano Lett ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38985516

RESUMO

The metal oxide electron transport layers (ETLs) of n-i-p perovskite solar cells (PSCs) are dominated by TiO2 and SnO2, while the efficacy of the other metal oxide ETLs still lags far behind. Herein, an emerging, economical, and environmentally friendly metal oxide, antimony oxide (Sb2Ox, x = 2.17), prepared by chemical bath deposition is reported as an alternative ETL for PSCs. The deposited Sb2Ox film is amorphous and very thin (∼10 nm) but conformal on rough fluorine-doped tin oxide substrates, showing matched energy levels, efficient electron extraction, and then reduced nonradiative recombination in PSCs. The champion PSC based on the Sb2Ox ETL delivers an impressive power conversion efficiency of 24.7% under one sun illumination, which represents the state-of-the-art performance of all metal oxide ETL-based PSCs. Additionally, the Sb2Ox-based devices show improved operational and thermal stability compared to their SnO2-based counterparts. Armed with these findings, we believe this work offers an optional ETL for perovskites-based optoelectronic devices.

7.
Chem Sci ; 15(28): 11099-11107, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39027288

RESUMO

Late-stage modification of peptides could potentially endow peptides with significant bioactivity and physicochemical properties, and thereby provide novel opportunities for peptide pharmaceutical studies. Since tryptophan (Trp) bears a unique indole ring residue and plays various critical functional roles in peptides, the modification methods for tryptophan were preliminarily developed with considerable progress via transition-metal mediated C-H activation. Herein, we report an unprecedented tertiary amine catalyzed peptide allylation via the SN2'-SN2' pathway between the N1 position of the indole ring of Trp and Morita-Baylis-Hillman (MBH) carbonates. Using this method that proceeds under mild conditions, we demonstrated an extremely broad scope of Trp-containing peptides and MBH carbonates to prepare a series of peptide conjugates and cyclic peptides. The reaction is amenable to either solid-phase (on resin) or solution-phase conditions. In addition, the modified peptides can be further conjugated with other biomolecules at Trp, providing a new handle for bioconjugation.

8.
Int J Biol Macromol ; 275(Pt 1): 133424, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38945330

RESUMO

The absence of effective therapeutic targets poses considerable obstacles to the treatment of triple-negative breast cancer (TNBC). This study aimed to explore the function and mechanism of polysaccharides derived from the aerial parts of Tetrastigma hemsleyanum (THP) for the treatment of TNBC. THP exerts notable anti-TNBC effects when used alone, and its combination with Doxorubicin (DOX) effectively augments the sensitivity of TNBC cells to DOX. Through RNA sequencing, Fe2+ assays, western blotting, and transmission electron microscopy, THP was identified as a natural inducer of ferroptosis and ferritinophagy through the xCT/GSH/GPX4 and Nrf2/NCOA4/FTH1 pathways. Further research revealed that the THP branched-chain hexose directly binds to the xCT protein to inhibit its expression and promotes ferroptosis. In vivo experiments confirmed the role of THP in inducing ferroptosis and showed that THP improves the tumor microenvironment and immune function by increasing the ratio of CD4+ and CD8+ T cells to regulatory T cells and modulating cytokine levels. As demonstrated by electrocardiography, blood chemistry, and histological analyses, THP alleviates organ toxicity caused by DOX. Overall, these results suggest that THP has significant clinical potential as a natural macromolecular drug and may provide a safe and effective treatment strategy for TNBC when combined with DOX.

9.
Environ Pollut ; 356: 124311, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38838811

RESUMO

Prolonged exposure to free silica leads to the development of silicosis, wherein activated fibroblasts play a pivotal role in its pathogenesis and progression. Fibroblast Activation Protein (FAP), as a biomarker for activated fibroblasts, its expression pattern and role in key aspects of silicosis pathogenesis remain unclear. This study elucidated the expression pattern and function of FAP through population-based epidemiological investigations, establishment of mouse models of silicosis, and in vitro cellular models. Results indicated a significant elevation of FAP in plasma from silicosis patients and lung tissues from mouse models of silicosis. In the cellular model, we observed a sharp increase in FAP expression early in the differentiation process, which remained high expression. Inhibition of FAP suppressed fibroblast differentiation, while overexpression of FAP produced the opposite effect. Moreover, fibroblast-derived FAP can alter the phenotype and function of neighboring macrophages. In summary, we revealed a high expression pattern of FAP in silicosis and its potential mechanistic role in fibrosis, suggesting FAP as a potential therapeutic target for silicosis.

10.
Mol Pharm ; 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38920116

RESUMO

The continuous evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evaded the efficacy of previously developed antibodies and vaccines, thus remaining a significant global public health threat. Therefore, it is imperative to develop additional antibodies that are capable of neutralizing emerging variants. Nanobodies, as the smallest functional single-domain antibodies, exhibit enhanced stability and penetration ability, enabling them to recognize numerous concealed epitopes that are inaccessible to conventional antibodies. Herein, we constructed an immune library based on the immunization of alpaca with the S1 subunit of the SARS-CoV-2 spike protein, from which two nanobodies, Nb1 and Nb2, were selected using phage display technology for further characterization. Both nanobodies, with the binding residues residing within the receptor-binding domain (RBD) region of the spike, exhibited high affinity toward the S1 subunit. Moreover, they displayed cross-neutralizing activity against both wild-type SARS-CoV-2 and 10 ο variants, including BA.1, BA.2, BA.3, BA.5, BA.2.75, BF.7, BQ.1, EG.5.1, XBB.1.5, and JN.1. Molecular modeling and dynamics simulations predicted that both nanobodies interacted with the viral RBD through their complementarity determining region 1 (CDR1) and CDR2. These two nanobodies are novel tools for the development of therapeutic and diagnostic countermeasures targeting SARS-CoV-2 variants and potentially emerging coronaviruses.

12.
Int Urol Nephrol ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38896370

RESUMO

PURPOSE: Chloride, the predominant anion in extracellular fluid from humans, is essential to maintaining homeostasis. One important metric for thoroughly assessing kidney function is the estimated glomerular filtration rate (eGFR). However, the relationship between variations in serum chloride concentration and eGFR in general populations has been poorly studied. Therefore, the purpose of this study is to elucidate the correlation between serum chloride levels and eGFR within the United States' adult population. METHODS: This cohort study was conducted using data from the National Health and Nutrition Examination Survey (NHANES), which covered the years 1999-2018. We employed multiple linear regression analysis and subgroup analysis to evaluate the correlation between serum chloride concentration and eGFR. To examine the nonlinear association between serum chloride levels and eGFR, restricted cubic spline analyses were employed. RESULTS: Data from 49,008 participants in this cohort study were used for the chloride analysis. In the comprehensively adjusted model, a noteworthy inverse relationship was discovered between chloride plasma concentration and eGFR. Restricted cubic spline analyses revealed a significant nonlinear relationship between chloride levels and eGFR (P for overall < 0.001 and P for nonlinear < 0.001). A significant interaction was observed between eGFR and plasma chloride concentration (all P < 0.001 for interaction) among the subgroups characterized by sex, household income to poverty ratio, BMI, hypertension, and diabetes. CONCLUSION: Our findings suggest that higher levels of chloride plasma concentration were linked to decreased eGFR. These findings underscore the significance of monitoring chloride plasma concentration as a potential indicator for identifying individuals at risk of developing chronic kidney disease (CKD).

13.
Cogn Neurodyn ; 18(3): 1227-1243, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38826659

RESUMO

The grid cells in the medial entorhinal cortex are widely recognized as a critical component of spatial cognition within the entorhinal-hippocampal neuronal circuits. To account for the hexagonal patterns, several computational models have been proposed. However, there is still considerable debate regarding the interaction between grid cells and place cells. In response, we have developed a novel grid-cell computational model based on cognitive space transformation, which established a theoretical framework of the interaction between place cells and grid cells for encoding and transforming positions between the local frame and global frame. Our model not only can generate the firing patterns of the grid cells but also reproduces the biological experiment results about the grid-cell global representation of connected environments and supports the conjecture about the underlying reason. Moreover, our model provides new insights into how grid cells and place cells integrate external and self-motion cues.

14.
Microbes Infect ; 26(5-6): 105348, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38697277

RESUMO

African swine fever virus (ASFV) infection causes African swine fever (ASF), a highly contagious and fatal disease that poses severe threat to swine production. To gain insights into the host responses to ASFV, we generated recombinant adenovirus Ad5 expressing viral membrane proteins p54, p17, and pB117L individually and infected an alveolar cell line, 3D4/21, with these recombinant viruses. Then, the cell lysates were analyzed using label-free quantification proteomic analysis method. A total of 2158 differentially expressed proteins (DEPs) were identified, of which 817, 466, and 875 proteins were from Ad5-p54-, Ad5-p17-, Ad5-pB117L-infected 3D4/21 cells, respectively. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed distinct yet interconnecting patterns of protein interaction networks. Specifically, the Ad5-p54 virus infection enriched the DEPs primarily involved in the metabolic pathways, endocytosis, adherens junction, and SNARE interactions in vesicular transport. The Ad5-p17 virus infection enriched the DEPs in endocytosis, ubiquitin-mediated proteolysis, N-Glycan biosynthesis, and apoptosis, while the Ad5-pB117L virus infection enriched the DEPs in metabolic pathways, endocytosis, oxidative phosphorylation, and focal adhesion. In summary, these results provide a comprehensive proteinomics analysis of the cellular responses to three ASFV membrane proteins, thus facilitating our understanding of ASFV pathogenesis.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Proteômica , Vírus da Febre Suína Africana/genética , Vírus da Febre Suína Africana/fisiologia , Vírus da Febre Suína Africana/metabolismo , Animais , Suínos , Proteômica/métodos , Linhagem Celular , Febre Suína Africana/virologia , Febre Suína Africana/metabolismo , Interações Hospedeiro-Patógeno , Mapas de Interação de Proteínas , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Proteínas da Matriz Viral/metabolismo , Proteínas da Matriz Viral/genética
15.
PLoS Pathog ; 20(5): e1012158, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38805567

RESUMO

SARS-CoV-2 is the third known coronavirus (CoV) that has crossed the animal-human barrier in the last two decades. However, little structural information exists related to the close genetic species within the SARS-related coronaviruses. Here, we present three novel SARS-related CoV spike protein structures solved by single particle cryo-electron microscopy analysis derived from bat (bat SL-CoV WIV1) and civet (cCoV-SZ3, cCoV-007) hosts. We report complex glycan trees that decorate the glycoproteins and density for water molecules which facilitated modeling of the water molecule coordination networks within structurally important regions. We note structural conservation of the fatty acid binding pocket and presence of a linoleic acid molecule which are associated with stabilization of the receptor binding domains in the "down" conformation. Additionally, the N-terminal biliverdin binding pocket is occupied by a density in all the structures. Finally, we analyzed structural differences in a loop of the receptor binding motif between coronaviruses known to infect humans and the animal coronaviruses described in this study, which regulate binding to the human angiotensin converting enzyme 2 receptor. This study offers a structural framework to evaluate the close relatives of SARS-CoV-2, the ability to inform pandemic prevention, and aid in the development of pan-neutralizing treatments.


Assuntos
Quirópteros , Microscopia Crioeletrônica , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , SARS-CoV-2/química , Animais , Humanos , Quirópteros/virologia , COVID-19/virologia , Sítios de Ligação , Betacoronavirus , Motivos de Aminoácidos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/química , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/metabolismo , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Modelos Moleculares , Ligação Proteica
16.
Biochem Pharmacol ; 225: 116269, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38723723

RESUMO

Antimicrobial peptides (AMPs), which have a low probability of developing resistance, are considered the most promising antimicrobial agents for combating antibiotic resistance. Feleucin-K3 is an amphiphilic cationic AMP that exhibits broad-spectrum antimicrobial activity. In our previous research, the first phenylalanine residue was identified as the critical position affecting its biological activity. Here, a series of Feleucin-K3 analogs containing hydrophobic D-amino acids were developed, leveraging the low sensitivity of proteases to unnatural amino acids and the regulatory effect of hydrophobicity on antimicrobial activity. Among them, K-1dF, which replaced the phenylalanine of Feleucin-K3 with its enantiomer (D-phenylalanine), exhibited potent antimicrobial activity with a therapeutic index of 46.97 and MICs between 4 to 8 µg/ml against both sensitive and multidrug-resistant Acinetobacter baumannii. The introduction of D-phenylalanine increased the salt tolerance and serum stability of Feleucin-K3. Moreover, K-1dF displayed a rapid bactericidal effect, a low propensity to develop resistance, and a synergistic effect when combined with antibiotics. More importantly, it exhibited considerable or superior efficacy to imipenem against pneumonia and skin abscess infection. In brief, the K-1dF obtained by simple and effective modification strategy has emerged as a promising candidate antimicrobial agent for tackling multidrug-resistant Acinetobacter baumannii infections.


Assuntos
Acinetobacter baumannii , Antibacterianos , Farmacorresistência Bacteriana Múltipla , Testes de Sensibilidade Microbiana , Acinetobacter baumannii/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/fisiologia , Animais , Antibacterianos/farmacologia , Antibacterianos/administração & dosagem , Substituição de Aminoácidos , Camundongos , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos/química , Peptídeos Antimicrobianos/administração & dosagem , Estabilidade de Medicamentos , Feminino
17.
Org Lett ; 26(22): 4767-4772, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38780227

RESUMO

A method for introducing a range of phosphonates into oligopeptides through a Michael addition reaction between dehydroalanine and phosphite is presented. The method offers a mild, cheap, and straightforward approach to peptide phosphorylation that has potential applications in chemical biology and medicinal chemistry. Moreover, the introduction of a phosphonate group into short antibacterial peptides is described to demonstrate its utility, leading to the discovery of phosphonated antibacterial peptides with potent broad-spectrum antibacterial activity.


Assuntos
Alanina , Antibacterianos , Oligopeptídeos , Organofosfonatos , Fosfitos , Organofosfonatos/química , Organofosfonatos/síntese química , Oligopeptídeos/química , Fosfitos/química , Estrutura Molecular , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/síntese química , Alanina/química , Alanina/análogos & derivados , Testes de Sensibilidade Microbiana , Fosforilação
18.
Elife ; 132024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38805545

RESUMO

As the most common degenerative joint disease, osteoarthritis (OA) contributes significantly to pain and disability during aging. Several genes of interest involved in articular cartilage damage in OA have been identified. However, the direct causes of OA are poorly understood. Evaluating the public human RNA-seq dataset showed that CBFB (subunit of a heterodimeric Cbfß/Runx1, Runx2, or Runx3 complex) expression is decreased in the cartilage of patients with OA. Here, we found that the chondrocyte-specific deletion of Cbfb in tamoxifen-induced Cbfbf/f;Col2a1-CreERT mice caused a spontaneous OA phenotype, worn articular cartilage, increased inflammation, and osteophytes. RNA-sequencing analysis showed that Cbfß deficiency in articular cartilage resulted in reduced cartilage regeneration, increased canonical Wnt signaling and inflammatory response, and decreased Hippo/Yap signaling and Tgfß signaling. Immunostaining and western blot validated these RNA-seq analysis results. ACLT surgery-induced OA decreased Cbfß and Yap expression and increased active ß-catenin expression in articular cartilage, while local AAV-mediated Cbfb overexpression promoted Yap expression and diminished active ß-catenin expression in OA lesions. Remarkably, AAV-mediated Cbfb overexpression in knee joints of mice with OA showed the significant protective effect of Cbfß on articular cartilage in the ACLT OA mouse model. Overall, this study, using loss-of-function and gain-of-function approaches, uncovered that low expression of Cbfß may be the cause of OA. Moreover, Local admission of Cbfb may rescue and protect OA through decreasing Wnt/ß-catenin signaling, and increasing Hippo/Yap signaling and Tgfß/Smad2/3 signaling in OA articular cartilage, indicating that local Cbfb overexpression could be an effective strategy for treatment of OA.


Assuntos
Cartilagem Articular , Via de Sinalização Hippo , Homeostase , Osteoartrite , Fator de Crescimento Transformador beta , Proteínas de Sinalização YAP , Animais , Cartilagem Articular/metabolismo , Camundongos , Osteoartrite/genética , Osteoartrite/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta/genética , Proteínas de Sinalização YAP/metabolismo , Proteínas de Sinalização YAP/genética , Via de Sinalização Wnt , beta Catenina/metabolismo , beta Catenina/genética , Transdução de Sinais , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética
19.
J Environ Manage ; 360: 121066, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38744202

RESUMO

The biotic nitrate reduction rate in freshwater ecosystems is typically constrained by the scarcity of carbon sources. In this study, 'two-chambers' - 'two-electrodes' photoautotrophic biofilm-soil microbial fuel cells (P-SMFC) was developed to accelerate nitrate reduction by activating in situ electron donors that originated from the soil organic carbon (SOC). The nitrate reduction rate of P-SMFC (0.1341 d-1) improved by âˆ¼ 1.6 times on the 28th day compared to the control photoautotrophic biofilm. The relative abundance of electroactive bacterium increased in the P-SMFC and this bacterium contributed to obtain electrons from SOC. Biochar amendment decreased the resistivity of P-SMFC, increased the electron transferring efficiency, and mitigated anodic acidification, which continuously facilitated the thriving of putative electroactive bacterium and promoted current generation. The results from physiological and ecological tests revealed that the cathodic photoautotrophic biofilm produced more extracellular protein, increased the relative abundance of Lachnospiraceae, Magnetospirillaceae, Pseudomonadaceae, and Sphingomonadaceae, and improved the activity of nitrate reductase and ATPase. Correspondingly, P-SMFC in the presence of biochar achieved the highest reaction rate constant for nitrate reduction (kobs) (0.2092 d-1) which was 2.4 times higher than the control photoautotrophic biofilm. This study provided a new strategy to vitalize in situ carbon sources in paddy soil for nitrate reduction by the construction of P-SMFC.


Assuntos
Fontes de Energia Bioelétrica , Biofilmes , Nitratos , Solo , Nitratos/metabolismo , Solo/química , Microbiologia do Solo , Eletrodos , Carbono/metabolismo , Oxirredução
20.
J Environ Manage ; 360: 121157, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38776659

RESUMO

In floodplains, phytoplankton communities are mainly shaped by environmental heterogeneity, hydrological connectivity, and habitat diversity. However, it remains unclear how hydrological connectivity drives phytoplankton biodiversity in floodplain lakes. This study was carried out in the Dongting Lake connected to the Yangtze River to ascertain the response mechanisms of phytoplankton communities to different hydrological connectivity gradients. We quantified the hydrological connectivity between lake and river habitats using in-lake water turnover time, and identified its relationship with phytoplankton community structure. Changes in hydrological connectivity can lead to different hydrodynamic and environmental conditions, which have a direct or indirect impact on phytoplankton community structure in water environments. The results showed that spatiotemporal changes in the hydrological connectivity and water environment led to distinct spatial variation in phytoplankton community structure across the study area. α and ß diversity showed a consistent change law with the change of turnover time, and the diversity index gradually increased with the decrease of hydrological connectivity, reaching the maximum value at the moderate hydrological connectivity, and then gradually decreasing. The peak of ß diversity occurs earlier than the peak of α diversity during the decline of hydrological connectivity. This study demonstrates that in-lake water turnover time has a non-negligible impact on phytoplankton community distribution in river-connected lakes. Phytoplankton can maintain the highest α diversity and possibly ß diversity under moderate hydrological connectivity, which is crucial for maintaining aquatic biodiversity in floodplain lakes.


Assuntos
Biodiversidade , Lagos , Fitoplâncton , Rios , Ecossistema
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