RESUMO
Superior photostability, minimal phototoxicity, red-shifted absorption/emission wavelengths, high brightness, and an enlarged Stokes shift are essential characteristics of top-tier organic fluorophores, particularly for long-lasting super-resolution imaging in live cells (e.g., via stimulated emission depletion (STED) nanoscopy). However, few existing fluorophores possess all of these properties. In this study, we demonstrate a general approach for simultaneously enhancing these parameters through the introduction of 9,9-dimethyl-9,10-dihydroacridine (DMA) as an electron-donating auxochrome. DMA not only induces red shifts in emission wavelengths but also suppresses photooxidative reactions and prevents the formation of triplet states in DMA-based fluorophores, greatly improving photostability and remarkably minimizing phototoxicity. Moreover, the DMA group enhances the fluorophores' brightness and enlarges the Stokes shift. Importantly, the "universal" benefits of attaching the DMA auxochrome have been exemplified in various fluorophores including rhodamines, difluoride-boron complexes, and coumarin derivatives. The resulting fluorophores successfully enabled the STED imaging of organelles and HaloTag-labeled membrane proteins.
Assuntos
Corantes Fluorescentes , Humanos , Rodaminas , Microscopia de Fluorescência/métodos , Células HeLa , IonóforosRESUMO
5,10-Dimethyl-5,10-dihydrophenazine (MP) is utilized as an effective auxochrome, leveraging its highly conjugated structure to enhance the photophysical and photochemical properties of fluorophores. As illustrated in the difluoride-boron complex and coumarin fluorophores, the extensive conjugation of MP auxochrome substantially red-shifts the absorption/emission wavelengths and increases Stokes shift due to the intensified intramolecular charge transfer effect; notably, MP auxochrome effectively improves fluorophores' photostability by mitigating photooxidative reactions through enhanced electron density delocalization on nitrogen atoms and increased ionization potential. Importantly, MP-based fluorophores demonstrate applicability in stimulated emission depletion nanomicroscopy, showcasing their utility in lipid droplet labeling.
RESUMO
Tumor microenvironment-responsive phototheranostic agents are highly sought after for their ability to improve diagnostic accuracy and treatment specificity. Here, we introduce a novel single-molecule probe, POZ-NO, which is activated by nitric oxide (NO) and weak acidity, enabling dual-mode imaging and photothermal therapy (PTT) of tumors. In acidic environments with elevated NO levels, POZ-NO exhibits a distinctive ratiometric fluorescence signal shift from the red to near-infrared, accompanied by a 700 nm photoacoustic signal. Additionally, POZ-NO demonstrated potent photothermal effects upon NO and acidity activation, achieving an impressive conversion efficiency of 74.3% under 735 nm laser irradiation. In vivo studies confirm POZ-NO's ability to accurately image tumors through ratiometric fluorescence and photoacoustic modes while selectively treating tumors with PTT.
Assuntos
Óxido Nítrico , Técnicas Fotoacústicas , Terapia Fototérmica , Microambiente Tumoral , Óxido Nítrico/análise , Óxido Nítrico/metabolismo , Óxido Nítrico/química , Animais , Humanos , Camundongos , Imagem Óptica , Concentração de Íons de Hidrogênio , Nanomedicina Teranóstica , Camundongos Endogâmicos BALB C , Feminino , Corantes Fluorescentes/química , FluorescênciaRESUMO
Glioblastoma multiforme (GBM) is a highly aggressive primary brain tumor associated with limited treatment options and high drug resistance, presenting significant challenges in the pursuit of effective treatment strategies. Epigenetic modifications have emerged as promising diagnostic biomarkers and therapeutic targets for GBM. For instance, histone deacetylase 6 (HDAC6) has been identified as a potential pharmacological target for GBM. Furthermore, the overexpression of monoamine oxidase A (MAO A) in glioma has been linked to tumor progression, making it an attractive target for therapy. In this study, we successfully engineered HDAC-MB, an activatable multifunctional small-molecule probe with the goal of efficiently detecting and killing glioma cells. HDAC-MB can be selectively activated by HDAC6, leading to the "turn on" of near-infrared fluorescence and effective inhibition of MAO A, along with potent photodynamic therapy (PDT) effects. Consequently, HDAC-MB not only enables the imaging of HDAC6 in live glioma cells but also exhibits the synergistic effect of MAO A inhibition and PDT, effectively inhibiting glioma invasion and inducing cellular apoptosis. The distinctive combination of features displayed by HDAC-MB positions it as a versatile and highly effective tool for the accurate diagnosis and treatment of glioma cells. This opens up opportunities to enhance therapy outcomes and explore future applications in glioma theranostics.
Assuntos
Glioblastoma , Glioma , Humanos , Desacetilase 6 de Histona/farmacologia , Desacetilase 6 de Histona/uso terapêutico , Glioma/diagnóstico por imagem , Glioma/tratamento farmacológico , Glioblastoma/patologia , Apoptose , Monoaminoxidase , Linhagem Celular Tumoral , Inibidores de Histona Desacetilases/farmacologiaRESUMO
The NHC-catalyzed enantioselective [4 + 2] annulation of 9H-fluorene-1-carbaldenydes with cyclic imines was successfully developed. A series of optically enriched polycyclic dihydroisoquinolinones were synthesized in moderate to excellent yields with good to excellent enantioselectivities. In addition, this efficient method could also be amenable to the synthesis of spirocyclic compounds by using isatin-derived ketimines as the electrophiles.
RESUMO
Fluorescence imaging has revolutionized the visualization of cellular structures and biomolecules due to its non-invasive nature and high sensitivity. Chromenoquinoline (CQ)-based dyes offer promising optical properties, yet their widespread application is hindered by aggregation-caused quenching (ACQ). In contrast, J-aggregates, characterized by distinctive photophysical properties, present a solution to ACQ. Here, we introduce a novel platform employing chromenoquinoline-benzimidazole (CQ-BI) dyes, capable of forming J-aggregates, for dual-color cellular imaging. The incorporation of a methyl group into the benzimidazole moiety enhances J-aggregate formation, leading to robust emission in both dilute solutions and aggregated states. Our study demonstrates that methyl moiety-modified CQ-BI derivatives enable simultaneous imaging of mitochondria and lipid droplets in living cells. This work underscores the potential of CQ-BI dyes for dual-channel fluorescence imaging, leveraging the unique properties of J-aggregation.
Assuntos
Benzimidazóis , Corantes Fluorescentes , Imagem Óptica , Quinolinas , Benzimidazóis/química , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Humanos , Quinolinas/química , Quinolinas/síntese química , Células HeLa , Estrutura Molecular , Mitocôndrias/química , Mitocôndrias/metabolismo , Cor , Benzopiranos/química , Benzopiranos/síntese químicaRESUMO
This study was designed to explore the expression changes of P2Y1 receptors in the distal colonic myenteric layer of rats. An opioid induced constipation(OIC) rat model was generated by intraperitoneal (i.p) injection of loperamide. At 7 days post-treatment, the model rats were assessed by calculating the fecal water content and the gastrointestinal transit ratio. The immunofluorescence (IF)-based histochemical study was used to observe the distribution of P2Y1 receptors in the distal colonic myenteric plexus. Western blotting (WB) was performed to evaluate the expression changes of P2Y1 proteins in the myenteric layer, and the electrophysiological approaches were carried out to determine the regulatory roles of P2Y1 receptors on distal colonic motor function. IF showed that P2Y1 receptors are co-expressed MOR in the enteric nerve cells of the distal colonic myenteric plexus. Moreover, the WB revealed that the protein levels of P2Y1 were significantly decreased in the distal colonic myenteric layer of OIC rats. In vitro tension experiments exhibited that the P2Y1 receptor antagonist MRS2500 enhanced the spontaneous contraction amplitude, adding EM2 and ß-FNA did not have any effect on MRS2500. Therefore, P2Y1 receptor expression could be associated with the occurrence of OIC in this rat model and the regulation of colonic motility by MOR may be related to the release of purine neurotransmitters such as ATP in the colonic nervous system.
Assuntos
Plexo Mientérico , Constipação Induzida por Opioides , Animais , Ratos , Analgésicos Opioides/efeitos adversos , Constipação Intestinal/induzido quimicamente , Western BlottingRESUMO
Xylitol, as an important food additive and fine chemical, has a wide range of applications, including food, medicine, chemical, and feed. This review paper focuses on the research progress of xylitol biosynthesis, from overcoming the limitations of traditional chemical hydrogenation and xylose bioconversion, to the full biosynthesis of xylitol production using green and non-polluting glucose as substrate. In the review, the molecular strategies of wild strains to increase xylitol yield, as well as the optimization strategies and metabolic reconfiguration during xylitol biosynthesis are discussed. Subsequently, on the basis of existing studies, the paper further discusses the current status of research and future perspectives of xylitol production using glucose as a single substrate. The evolution of raw materials from xylose-based five-carbon sugars to glucose is not only cost-saving, but also safe and environmentally friendly, which brings new opportunities for the green industrial chain of xylitol.
RESUMO
Nonalcoholic fatty liver disease (NAFLD) can progress to cirrhosis and liver cancer if left untreated. Therefore, it is of great importance to develop useful tools for the noninvasive and accurate diagnosis of NAFLD. Increased microenvironmental viscosity was considered as a biomarker of NAFLD, but the occurrence of increased viscosity in other liver diseases highly reduces the diagnosis accuracy of NAFLD by a single detection of viscosity. Hence, it is very necessary to seek a second biomarker of NAFLD. It has been innovatively proposed that the overexpressed heme oxygenase-1 enzyme in NAFLD would produce abnormally high concentrations of CO in hepatocytes and that CO could serve as a potential biomarker. In this work, we screened nine lactam Changsha dyes (HCO-1-HCO-9) with delicate structures to obtain near-infrared (NIR), metal-free, and "dual-locked" fluorescent probes for the simultaneous detection of CO and viscosity. Changsha dyes with a 2-pyridinyl hydrazone substituent could sense CO, and the 5-position substituents on the 2-pyridinyl moiety had a great electron effect on the reaction rate. The double bond in these dyes served as the sensing group for viscosity. Probe HCO-9 was utilized for precise diagnosis of NAFLD by simultaneous detection of CO and viscosity. Upon reacting with CO in a high-viscosity microenvironment, strong fluorescence at 745 nm of probe HCO-9 was turned on with NIR excitation at 700 nm. Probe HCO-9 was proven to be an effective tool for imaging CO and viscosity. Due to the advantages of NIR absorption and low toxicity, probe HCO-9 was successfully applied to image NAFLD in a mouse model.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Corantes Fluorescentes/química , Monóxido de Carbono , Viscosidade , BiomarcadoresRESUMO
An enantioselective construction of pyrazolo[3,4-b]pyridones was achieved via N-heterocyclic carbene-catalyzed [3 + 3] annulation of enals with 5-aminopyrazoles. This protocol not only offers a highly efficient synthetic approach for the preparation of various substituted pyrazolo[3,4-b]pyridones but also provides an effective method for the rapid synthesis of enantiopure spirooxindone derivatives.
RESUMO
An N-heterocyclic carbene-catalyzed atroposelective [3 + 3] annulation of enals with 2-aminomaleate derivatives is described. A series of substituted dihydropyridones bearing both C-N axis and point chirality were synthesized with good diastereo- and enantioselectivity under mild conditions. This efficient strategy successfully superpositions an extra point chiral element with an axial backbone, and the generated structurally interesting atropisomers may have potential application in drug discovery.
RESUMO
Humulus scandens, (Lour.) Merr., is a climbing herb which are used as traditional Chinese medicine, a raw material for papermaking, making soap, and replacing hops H. lupulus. This herb is distributed in many provinces of China, including Sichuan province. During March and June 2022, powdery mildew was found on leaves of H. scandens in the modern agricultural high-tech demonstration garden of Sichuan Academy of Agricultural Science, Chengdu, Sichuan Province, China. Abundant white or grayish powdery colonies could be seen on the surface of leaves, and 30%-100% of leaf areas were affected. Some of the infected leaves were either chlorotic or senescent. About 90% of the observed plants showed powdery mildew symptoms. Conidiophores (n = 25) were 74.0 to 160.1 µm × 8.7 to 12.7 µm (on average 120.9 × 10.4 µm) and composed of cylindrical foot cells (length 31.9-72.9 µm, average 50.1 µm) and conidia (mostly 10 conidia) in chains. Barrel-shaped conidia with fibrosin bodies (n = 30) were 12.8 to 21.0 µm × 7.9 to 15 µm, on average 16.7 × 11.3 µm, with a length/width ratio of 1.5. Chasmothecia were not found. Based on these morphologic characteristics, the pathogen was initially identified as Podosphaera macularis (Braun and Cook 2012; Mahaffee et al. 2009). To confirm the identification, two isolates (PDLC0315 and PDLC0412) of P. macularis mycelia and conidia were collected, and mycelia and conidia were combined for a single DNA extraction from each isolate. With the total genomic DNA, the sequences of the internal transcribed spacer (ITS), 5.8S rRNA, the 18S and 28S large subunit ribosomal DNA (LSU) (Bradshaw and Tobin 2020; White et al. 1990), were bi-directionally sequenced and deposited in GenBank (ON862625.1 and ON862630.1). The ON862625.1 and ON862630.1 showed 100% similarity with sequences of P. macularis isolate CT1 (MH687414.1). Phylogenetic analyses based on the combined ITS and 28S rDNA sequences indicated that the two specimens, PDLC0315 and PDLC0412 formed a monophyletic clade together with sequences retrieved from Podosphaera macularis CT1 and Head quarter 31 (KX842348.1). The pathogenicity test with the fungus was confirmed by gently pressing the infected leaves onto three healthy wild plants from the same geographical location. Three uninoculated wild plants served as controls. Six inoculated and non-inoculated plants were placed in different growth chambers with a 16-h photoperiod at 22±2°C and 70% of relative humidity. After 10 to 14 days, powdery mildew colonies developed on inoculated plants. Non-inoculated control plants did not show any symptoms. The fungus on inoculated leaves was morphologically identical to that first observed in the garden. As far as we know, this study is the first report of powdery mildew disease in Humulus scandens caused by Podosphaera macularis in China. Rapid expansion and wild distribution of H. scandens could lead to increased powdery mildew risk in outdoor cultivation. Due to the invasive potential of the powdery mildew fungi, this record is important in the context of the range extension of Podosphaera macularis.
RESUMO
Photoaffinity labeling is a powerful technique to interrogate drug-protein interactions in native cellular environments. Photo-cross-linkers are instrumental for this technique. However, the introduction of unnatural photo-cross-linkers may significantly reduce the bioactivity of the drug, thus impairing the chemoproteomic outcomes. Herein, we developed a common pharmacophore, isoxazole, into a natively embedded photo-cross-linker for chemoproteomics, which minimally perturbs the drug structure. The photo-cross-linking reactions of the isoxazole were thoroughly investigated for the first time. Functionalized isoxazoles were then designed and applied to protein labeling, demonstrating the superior photo-cross-linking efficiency. Subsequently, two isoxazole-based drugs, Danazol and Luminespib, were employed in chemoproteomic studies, revealing their potential cellular targets. These results provide valuable strategies for future chemoproteomic study and drug development.
Assuntos
Marcadores de Fotoafinidade , Proteínas , Marcadores de Fotoafinidade/química , Proteínas/química , Isoxazóis , Reagentes de Ligações Cruzadas/químicaRESUMO
The elusive mechanism of action between signaling molecules H2O2 and H2S in oxidative stress demands a fluorescent probe, capable of their detection in a discriminative and dynamic manner. Herein we report the design and study of a probe TCAB. As demonstrated, it responds to H2O2 and H2S selectively and sensitively to generate distinct fluorescence signals and patterns. Cyan imaging for H2O2 in a ratiometric fashion and two-colored, enhanced blue and newly produced red for H2S are observed. When both are present, the sequential reaction of H2O2 and H2S with the probe gives cyan then red signal, while the reverse sequence produces an inverse red-cyan signal. The unrivaled discriminative multicolor imaging capacity of the probe enables us to monitor dynamic H2O2 and H2S redox processes in living cells and organisms. It is expected that the probe could serve as a powerful tool to investigate the correlation and distinction of biologically significant H2S- and H2O2-engaged redox processes.
Assuntos
Corantes Fluorescentes/química , Peróxido de Hidrogênio/análise , Sulfeto de Hidrogênio/análise , Animais , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Peróxido de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/metabolismo , Microscopia de Fluorescência , Estrutura Molecular , Imagem Óptica , Oxirredução , Células Tumorais Cultivadas , Peixe-ZebraRESUMO
BACKGROUND: Yokose virus was first isolated from bats (Miniopterus fuliginosus) collected in Yokosuka, Japan, in 1971, and is a new member of the family Flaviviridae, genus Flavivirus. In this study, we isolated a Yokose virus from a serum sample of Myotis daubentonii (order Chiroptera, family Vespertilionidae) collected in Yunnan province, China in 2013. METHODS: The serum specimens of bat were used to inoculate in BHK-21 and Vero E6 cells for virus isolation. Then the viral complete genome sequence was obtained and was used for phylogenetic analysis performed by BEAST software package. RESULTS: The virus was shown to have cytopathic effects in mammalian cells (BHK-21 and Vero E6). Genome sequencing indicated that it has a single open reading frame (ORF), with a genome of 10,785 nucleotides in total. Phylogenetic analysis of the viral genome suggests that XYBX1332 is a Yokose virus (YOKV) of the genus Flavivirus. Nucleotide and amino acid homology levels of the ORF of XYBX1332 and Oita-36, the original strain of YOKV, were 72 and 82%, respectively. The ORFs of XYBX1332 and Oita-36 encode 3422 and 3425 amino acids, respectively. In addition, the non-coding regions (5'- and 3'-untranslated regions [UTRs]) of these two strains differ in length and the homology of the 5'- and 3'-UTRs was 81.5 and 78.3%, respectively. CONCLUSION: The isolation of YOKV (XYBX1332) from inland China thousands of kilometers from Yokosuka, Japan, suggests that the geographical distribution of YOKV is not limited to the islands of Japan and that it can also exist in the inland areas of Asia. However, there are large differences between the Chinese and Japanese YOKV strains in viral genome.
Assuntos
Quirópteros/virologia , Flavivirus/genética , Variação Genética , Genoma Viral , Animais , China , Chlorocebus aethiops , Flavivirus/isolamento & purificação , Infecções por Flavivirus/veterinária , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Células Vero , Sequenciamento Completo do GenomaRESUMO
BACKGROUND: Microalgae have been proposed as potential platform to produce lipid-derived products, such as biofuels. Knowledge on the intracellular carbon flow distribution may identify key metabolic processes during lipid synthesis thus refining culture/genetic strategies to maximize cell lipid productivity. A kinetic metabolic model simulating cell metabolic behavior and lipid production was first applied in the microalgae platform Chlorella protothecoides under heterotrophic condition. It combines both physiology and flux information in a kinetic approach. Cell nutrition, growth, lipid production and almost 30 metabolic intermediates covering central carbon metabolism were included and simulated. RESULTS: Model simulations were shown to adequately agree with experimental data, which is suggesting that the proposed model copes with Chlorella protothecoides cells' biology. The dynamic metabolic flux analysis using the model showed a reversible starch flux from accumulation to decomposing when glucose reached depletion, while net lipid flux shows a quasi-constant rate. The sensitive flux parameters on starch and lipid metabolism suggested that starch synthesis is the major competing pathway that affects lipid accumulation in C. protothecoides. Flux analysis also demonstrated that high lipid yield under heterotrophic condition is accompanied with high lipid flux and low TCA activity. Meanwhile, the dynamic flux distribution also suggests a relatively constant ratio of glucose distributed to biomass, lipid, starch, nucleotides as well as pentose phosphate pathway. CONCLUSION: The model described not only experimental data, but also unraveled intracellular carbon flow distribution and identify key metabolic processes during lipid synthesis. Most of the metabolic kinetics also showed statistical significance for metabolic mechanism. Therefore, this study unravels the mechanisms of the glucose impact on the dynamic carbon flux distribution, thus improving our understanding of the links between carbon fluxes and lipid metabolism in C. protothecoides.
Assuntos
Chlorella/metabolismo , Lipídeos/biossíntese , Lipídeos/química , Carbono/metabolismo , Chlorella/química , Chlorella/crescimento & desenvolvimento , Glucose/metabolismo , Processos Heterotróficos , Cinética , Análise do Fluxo Metabólico , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Via de Pentose Fosfato , Amido/metabolismoRESUMO
Tumor-associated macrophages (TAMs) are major components of the tumor microenvironment. Although a role for TAMs in promoting tumor progression has been revealed, the differentiation mechanisms and intrinsic signals of TAMs regulated by the tumor microenvironment remain unclear. Here we constructed an in vitro TAMs cell model, TES-TAMs, which is from tumor-extract-stimulated bone-marrow-derived macrophages. We performed a comparative proteomics analysis of bone-marrow-derived macrophages and TES-TAMs, which indicated that TES-TAMs possessed characteristic molecular expression of TAMs. Intriguingly, the signal pathways enriched in up-regulated differentially expressed proteins of TAMs demonstrated that glycolysis metabolism reprogramming may play an important role in TAM differentiation. We found that hexokinase-2, a key mediator of aerobic glycolysis, and the downstream proteins PFKL and ENO1 were remarkably increased in both TES-TAMs and primary TAMs from our MMTV-PyMT mice model. This phenomenon was then verified in human THP-1 cell lines stimulated by tumor extract solution from breast cancer patient. Taken together, our study provides insight into the induction of TAM differentiation by the tumor microenvironment through metabolic reprogramming.
Assuntos
Reprogramação Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Macrófagos/efeitos dos fármacos , Neoplasias Mamárias Experimentais/genética , Redes e Vias Metabólicas/efeitos dos fármacos , Proteoma/genética , Microambiente Tumoral/genética , Animais , Diferenciação Celular , Misturas Complexas/farmacologia , Citocinas/genética , Citocinas/metabolismo , Feminino , Hexoquinase/genética , Hexoquinase/metabolismo , Humanos , Macrófagos/metabolismo , Macrófagos/patologia , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/patologia , Redes e Vias Metabólicas/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteoma/metabolismo , Transdução de Sinais , Carga TumoralRESUMO
BACKGROUND: Microalgae have the potential to rapidly accumulate lipids of high interest for the food, cosmetics, pharmaceutical and energy (e.g. biodiesel) industries. However, current lipid extraction methods show efficiency limitation and until now, extraction protocols have not been fully optimized for specific lipid compounds. The present study thus presents a novel lipid extraction method, consisting in the addition of a water treatment of biomass between the two-stage solvent extraction steps of current extraction methods. The resulting modified method not only enhances lipid extraction efficiency, but also yields a higher triacylglycerols (TAG) ratio, which is highly desirable for biodiesel production. RESULTS: Modification of four existing methods using acetone, chloroform/methanol (Chl/Met), chloroform/methanol/H2O (Chl/Met/H2O) and dichloromethane/methanol (Dic/Met) showed respective lipid extraction yield enhancement of 72.3, 35.8, 60.3 and 60.9%. The modified acetone method resulted in the highest extraction yield, with 68.9 ± 0.2% DW total lipids. Extraction of TAG was particularly improved with the water treatment, especially for the Chl/Met/H2O and Dic/Met methods. The acetone method with the water treatment led to the highest extraction level of TAG with 73.7 ± 7.3 µg/mg DW, which is 130.8 ± 10.6% higher than the maximum value obtained for the four classical methods (31.9 ± 4.6 µg/mg DW). Interestingly, the water treatment preferentially improved the extraction of intracellular fractions, i.e. TAG, sterols, and free fatty acids, compared to the lipid fractions of the cell membranes, which are constituted of phospholipids (PL), acetone mobile polar lipids and hydrocarbons. Finally, from the 32 fatty acids analyzed for both neutral lipids (NL) and polar lipids (PL) fractions, it is clear that the water treatment greatly improves NL-to-PL ratio for the four standard methods assessed. CONCLUSION: Water treatment of biomass after the first solvent extraction step helps the subsequent release of intracellular lipids in the second extraction step, thus improving the global lipids extraction yield. In addition, the water treatment positively modifies the intracellular lipid class ratios of the final extract, in which TAG ratio is significantly increased without changes in the fatty acids composition. The novel method thus provides an efficient way to improve lipid extraction yield of existing methods, as well as selectively favoring TAG, a lipid of the upmost interest for biodiesel production.
Assuntos
Chlorella/química , Lipídeos/isolamento & purificação , Extração Líquido-Líquido/métodos , Triglicerídeos/análise , Biocombustíveis , Biomassa , Fracionamento Celular/métodos , Chlorella/citologia , Ácidos Graxos/análise , Ácidos Graxos/química , Ácidos Graxos/isolamento & purificação , Lipídeos/análise , Lipídeos/química , Metanol , Solventes , Triglicerídeos/isolamento & purificação , ÁguaRESUMO
The effect of aggregation configuration of molecular fluorophore citrazinic acid (CZA) on the photoluminescence (PL) properties of carbon dots (CDs) has been investigated using first-principles method. The structural stability of all aggregates has been analyzed, and the results show that the most stable structures are J-type CZA aggregates with head-to-tail configurations and the CZA/CD aggregates are bonded by replacing H atoms on the CD edges with de-OH from the pyridine ring of CZA. The luminescent properties of CZA/CD aggregates are mainly affected by the binding modes and binding sites. When the sites belong to electron-donating groups, electron-withdrawing groups or sp2 domain, the PL spectra of CDs are shifted and the luminescent intensities are significantly enhanced. The results suggest that covalently bonded CZA/CD aggregates are responsible for the high fluorescence quantum yield of CD. Moreover, the distance between the centers of the two pyridine rings in H-type CZA dimers less than 3.5 Å is prone to π-π stacking, leading to fluorescence quenching of aggregates. The present work is helpful in understanding the effect of molecular fluorophores on the PL properties of CDs and provides theoretical guidance for the controllable synthesis of CDs.
RESUMO
BACKGROUND: Neuropathic pain (NP) is a common type of pain in clinic. Due to the limited effect of drug treatment, many patients with NP are still troubled by this disease. In recent years, complementary and alternative therapy (CAT) has shown good efficacy in the treatment of NP. As the interest in CAT for NP continues to grow, we conducted a bibliometric study of publications on CAT treatment for NP. The aim of this study is to analyze the development overview, research hotspots and future trends in the field of CAT and NP through bibliometric methodology, so as to provide a reference for subsequent researchers. METHODS: Publications on CAT in the treatment of NP from 2002 to 2022 were retrieved from the Web of Science Core Collection. Relevant countries, institutions, authors, journals, keywords, and references were analyzed bibliometrically using Microsoft Excel 2021, bibliometric platform, VOSviewer, and CiteSpace. RESULTS: A total of 898 articles from 46 countries were published in 324 journals, and they were contributed by 4455 authors from 1102 institutions. The most influential country and institution are China (nâ =â 445) and Kyung Hee University (nâ =â 63), respectively. Fang JQ (nâ =â 27) and Evidence-Based Complementary and Alternative Medicine (nâ =â 63) are the author and journal with the most publications in this field. The clinical efficacy, molecular biological mechanisms and safety of CAT for NP are currently hot directions. Low back pain, postherpetic neuralgia, acupuncture, and herbal are the hot topics in CAT and NP in recent years. CONCLUSION: This study reveals the current status and hotspots of CAT for NP. The study also indicates that the effectiveness and effect mechanism of acupuncture or herbs for treating emotional problems caused by low back pain or postherpetic neuralgia may be a trend for future research.