RESUMEN
The photocatalytic CO2-to-CH4 conversion involves multiple consecutive proton-electron coupling transfer processes. Achieving high CH4 selectivity with satisfactory conversion efficiency remains challenging since the inefficient proton and electron delivery path results in sluggish proton-electron transfer kinetics. Herein, we propose the fabrication of atomically adjacent anion-cation vacancy as paired redox active sites that could maximally promote the proton- and electron-donating efficiency to simultaneously enhance the oxidation and reduction half-reactions, achieving higher photocatalytic CO2 reduction activity and CH4 selectivity. Taking TiO2 as a photocatalyst prototype, the operando electron paramagnetic resonance spectra, quasi in situ X-ray photoelectron spectroscopy measurements, and high-angle annular dark-field-scanning transmission electron microscopy image analysis prove that the VTi on TiO2 as initial sites can induce electron redistribution and facilitate the escape of the adjacent oxygen atom, thereby triggering the dynamic creation of atomically adjacent dual-vacancy sites during photocatalytic reactions. The dual-vacancy sites not only promote the proton- and electron-donating efficiency for CO2 activation and protonation but also modulate the coordination modes of surface-bound intermediate species, thus converting the endoergic protonation step to an exoergic reaction process and steering the CO2 reduction pathway toward CH4 production. As a result, these in situ created dual active sites enable nearly 100% CH4 selectivity and evolution rate of 19.4 µmol g-1 h-1, about 80 times higher than that of pristine TiO2. Thus, these insights into vacancy dynamics and structure-function relationship are valuable to atomic understanding and catalyst design for achieving highly selective catalysis.
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Formamide (HCONH2) plays a pivotal role in the manufacture of a diverse array of chemicals, fertilizers, and pharmaceuticals. Photocatalysis holds great promise for green fabrication of carbon-nitrogen (C-N) compounds owing to its environmental friendliness and mild redox capability. However, the selective formation of the C-N bond presents a significant challenge in the photocatalytic synthesis of C-N compounds. This work developed a photocatalytic radical coupling method for the formamide synthesis from co-oxidation of ammonia (NH3) and methanol (CH3OH). An exceptional formamide yield rate of 5.47 ± 0.03 mmol·gcat-1·h-1 (911.87 ± 0.05 mmol·gBi-1·h-1) was achieved over atomically dispersed Bi sites (BiSAs) on TiO2. An accumulation of 45.0 mmol·gcat-1 (0.2 g·gcat-1) of formamide was achieved after long-term illumination, representing the highest level of photocatalytic C-N compounds synthesis. The critical C-N coupling for formamide formation originated from the "σ-σ" interaction between electrophilic âCH2OH with nucleophilic âNH2 radical. The BiSAs sites facilitated the electron transfer between reactants and photocatalysts and enhanced the nucleophilic attack of âNH2 radical at the âCH2OH radical, thereby advancing the selective C-N bond formation. This work deepens the understanding of the C-N coupling mechanism and offers an alternative and intriguing photocatalytic approach for the efficient and sustainable production of C-N compounds.
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Vasohihibin-2 (VASH2) is a homolog of vasohibin-1 (VASH1) and is overexpressed in various cancers. Vasohihibin-2 acts on both cancer cells and cancer microenvironmental cells. Previous analyses have shown that VASH2 promotes cancer progression and abrogation of VASH2 results in significant anticancer effects. We therefore propose VASH2 to be a practical molecular target for cancer treatment. Modifications of antisense oligonucleotide (ASO) such as bridged nucleic acids (BNA)-based modification increases the specificity and stability of ASO, and are now applied to the development of a number of oligonucleotide-based drugs. Here we designed human VASH2-ASOs, selected an optimal one, and developed 2',4'-BNA-based VASH2-ASO. When systemically administered, naked 2',4'-BNA-based VASH2-ASO accumulated in the liver and showed its gene-silencing activity. We then examined the effect of 2',4'-BNA-based VASH2-ASO in liver cancers. Intraperitoneal injection of naked 2',4'-BNA-based VASH2-ASO exerted a potent antitumor effect on orthotopically inoculated human hepatocellular carcinoma cells. The same manipulation also showed potent antitumor activity on the splenic inoculation of human colon cancer cells for liver metastasis. These results provide a novel strategy for the treatment of primary as well as metastatic liver cancers by using modified ASOs targeting VASH2.
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Neoplasias Hepáticas , Oligonucleótidos Antisentido , Humanos , Oligonucleótidos Antisentido/genética , Oligonucleótidos Antisentido/farmacología , Oligonucleótidos Antisentido/uso terapéutico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Línea Celular , Factores de Transcripción , Oligonucleótidos/farmacología , Oligonucleótidos/uso terapéutico , Proteínas de Ciclo Celular/genética , Proteínas AngiogénicasRESUMEN
Oligonucleotides with an amino linker at the 3'-end are useful for the preparation of conjugated oligonucleotides. However, chemically modified nucleosides, which are unstable under basic conditions, cannot be incorporated into oligonucleotides using the conventional method entailing the preparation of oligonucleotides bearing a 3'-amino linker. Therefore, we designed Fmoc-protected phosphoramidites for the synthesis of base-labile oligonucleotides modified with a 3'-amino linker. The resultant phosphoramidites were then successfully incorporated into oligonucleotides bearing a 3'-amino linker. Various basic solutions were investigated for protecting group removal. All the protecting groups were removed by treating the oligonucleotides with 40% aqueous methylamine at room temperature for 2 h. Thus, the deprotection time and temperature were significantly reduced compared to the conventional conditions (28% NH3 aq., 55 °C, 17 h). In addition, the oligonucleotide protecting groups could be removed using a mild base (e.g., 50 mM potassium carbonate methanol solution). Furthermore, base-labile oligonucleotides bearing an amino linker at the 3'-end were successfully synthesized using the developed phosphoramidite reagents, highlighting the utility of our strategy.
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Oligonucleótidos , Compuestos Organofosforados , Indicadores y Reactivos , NucleósidosRESUMEN
Present guidelines recommend a multidisciplinary team (MDT) approach to diabetic foot ulcer (DFU) care, but relevant data from Asia are lacking. We aim to evaluate the clinical and economic outcomes of an MDT approach in a lower extremity amputation prevention programme (LEAPP) for DFU care in an Asian population. We performed a case-control study of 84 patients with DFU between January 2017 and October 2017 (retrospective control) vs 117 patients with DFU between December 2017 and July 2018 (prospective LEAPP cohort). Comparing the clinical outcomes between the retrospective cohort and the LEAPP cohort, there was a significant decrease in mean time from referral to index clinic visit (38.6 vs 9.5 days, P < .001), increase in outpatient podiatry follow-up (33% vs 76%, P < .001), decrease in 1-year minor amputation rate (14% vs 3%, P = .007), and decrease in 1-year major amputation rate (9% vs 3%, P = .05). Simulation of cost avoidance demonstrated an annualised cost avoidance of USD $1.86m (SGD $2.5m) for patients within the LEAPP cohort. In conclusion, similar to the data from Western societies, an MDT approach in an Asian population, via a LEAPP for patients with DFU, demonstrated a significant reduction in minor and major amputation rates, with annualised cost avoidance of USD $1.86m.
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Diabetes Mellitus , Pie Diabético , Úlcera del Pie , Amputación Quirúrgica , Estudios de Casos y Controles , Pie Diabético/prevención & control , Pie Diabético/cirugía , Humanos , Extremidad Inferior , Grupo de Atención al Paciente , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
We report on a high-peak-power electro-optically Q-switched laser emitting a near-diffraction-limited beam profile at 1064 nm by using a gradient-doped Nd:YAG crystal. The gradient-doped crystal features a unique combination of a reduced thermal lens effect through effectively spreading the heat load distribution within its volume. Its performance is compared with those of Nd:YAG crystals with uniform volume doping distribution operating in the Q-switched regime with the same laser configuration, demonstrating the higher average and peak power achievable with the gradient-doped crystal. The maximum average output power amounts to 6.9 W at a pulse repetition rate of 2 kHz, which corresponds to a maximum peak power of â¼585kW. Compared to homogeneous dopant crystals, the slope efficiency and average output power increased by 30.8% and 21.1%, respectively.
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BACKGROUND: Osteosarcoma is a common primary malignant bone tumor susceptible to distant metastasis. The clinical outcome for patients remains poor due to the resistance to chemotherapy and lacking effective therapeutic targets. Recepteur d'origine nantais (RON), a transmembrane protein of the c-MET proto-oncogene family, has been reported to contribute to the malignant progression and bone metastasis in several tumors. The present study aimed to explore the prognostic significance of RON in primary high-grade osteosarcoma. METHODS: Immunohistochemistry (IHC) and western blotting (WB) were used to investigate the protein expression of RON in 80 surgically resected specimens (50 high-grade osteosarcoma specimens and 30 non-neoplastic bone tissues) and 6 cell lines. The χ2 test or independent-sample Student's t-test was used to assess the significance of RON difference between osteosarcoma and non-neoplastic bone tissues. The χ2 test and Fisher's exact test were used to analyze the association of RON with the clinicopathological features of osteosarcoma patients. Kaplan-Meier method and Cox proportional hazards model were used to assess the significance of RON for the survival of osteosarcoma patients. RESULTS: The results of IHC and WB observed significant overexpression of RON in osteosarcoma specimens (P < 0.001) and osteosarcoma cell lines. Moreover, immunohistochemical high expression of RON was associated with a poor response to chemotherapy (P = 0.032) as well as worse progression-free (P = 0.003) and overall (P < 0.001) survival of osteosarcoma patients. Multivariate analysis revealed that high expression of RON was independently associated with reduced progression-free (P = 0.027, HR = 2.31) and overall survival (P = 0.004, HR = 5.06) time of osteosarcoma patients. CONCLUSIONS: The present study demonstrated that high expression of RON held independent value for unfavorable survival in primary high-grade osteosarcoma. Its potential role as a therapeutic target for osteosarcoma treatment deserves further research.
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Osteosarcoma , Humanos , Inmunohistoquímica , Pronóstico , Proto-Oncogenes Mas , Proteínas Tirosina Quinasas ReceptorasRESUMEN
Immuno-positron emission tomography (immuno-PET) is expected to improve the specificity of small chemical tracers such as 18F-fluorodeoxyglucose. Whole antibodies significantly accumulate in target molecule-expressing tumors but frequently persist too long in the blood circulation for imaging purposes. We investigated the utility of whole antibodies, 64Cu-labeled via a urokinase-substrate linker, and their exogenous urokinase-responsive cleavage to enhance clearance of immuno-PET probes from the blood and shorten the time required to develop adequate imaging contrast. Specifically, we used 64Cu-labeled trastuzumab in human epidermal growth factor receptor 2 (HER2)-positive tumor-bearing mice. 64Cu-labeled trastuzumab with a urokinase-cleavage site (64Cu-CB-TE1A1P-USL-trastuzumab) was synthesized using a bifunctional chelator incorporating an urokinase substrate peptide. Urokinase cleavage was analyzed in vitro by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and radio-gel permeation-high-performance liquid chromatography. Improvements in radioisotope clearance and HER2-imaging by urokinase injection were evaluated by PET imaging and ex vivo biodistribution studies in A431 tumor-bearing mice. 64Cu-CB-TE1A1P-USL-trastuzumab was cleaved into smaller radioactive fragments by 20â¯000 IU/mL urokinase treatment in vitro at an efficacy of â¼95%. The probe targeted HER2 in A431 tumors in mice within 24 h post-injection, and approximately two-thirds of the probe in the blood circulation was eliminated via renal clearance of radioactive fragments after three urokinase injections. Therefore, the tumor/blood ratio increased 3.0-fold. Without urokinase injection, the tumor accumulation of 64Cu-CB-TE1A1P-USL-trastuzumab slowly increased, and the blood radioactivity decreased over 72 h. However, the tumor/blood ratios in mice after three urokinase injections were higher at 24 h than those in mice without injections at 72 h. The results indicate that our approach shortened the time required to develop adequate imaging contrast of immuno-PET by >2 days. Therefore, this approach can benefit high-sensitivity imaging under lower radioactive decay conditions and can decrease patient radiation exposure. In addition, it could reduce other adverse effects of radioimmunotherapy.
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Radioisótopos de Cobre/química , Neoplasias/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Receptor ErbB-2/metabolismo , Trastuzumab/metabolismo , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Animales , Línea Celular Tumoral , Quelantes/química , Fluorodesoxiglucosa F18 , Compuestos Heterocíclicos con 2 Anillos/química , Xenoinjertos , Humanos , Inyecciones Intravenosas , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Trasplante de Neoplasias , Neoplasias/patología , Organofosfonatos/química , Distribución Tisular , Trastuzumab/química , Activador de Plasminógeno de Tipo Uroquinasa/administración & dosificaciónRESUMEN
The effects of low salinity (transferred from 31 to 26, 21, and 16) on the regulation pathways of neuroendocrine-immunoregulatory network were investigated in Litopenaeus vannamei. The results showed that the hormones (corticotrophin-releasing hormone, adrenocorticotropic hormone) and biogenic amines (dopamine, noradrenaline, 5-hydroxytryptamine) concentrations in lower salinity groups increased significantly within 12 h. The gene expression of biogenic amine receptors showed that dopamine receptor D4 and α2 adrenergic receptor in lower salinity groups decreased significantly within 12 h, whereas the 5-HT7 receptor significantly increased within 1d. The second messenger synthetases (adenylyl cyclase, phospholipase C) and the second messengers (cyclic adenosine monophosphate, cyclic guanosine monophosphate) of lower salinity groups shared a similar trend in which adenylyl cyclase and cyclic adenosine monophosphate reached the maximum at 12 h, whereas phospholipase C and cyclic guanosine monophosphate reached the minimum. The immune parameters (total hemocyte count, phenoloxidase activity, phagocytic activity, crustin expression, antibacterial activity, C-type lectin expression, hemagglutinating activity) in lower salinity groups decreased significantly within 12 h. Except for the total hemocyte count, all the parameters recovered to the control levels afterwards. Therefore, it may be concluded that the neuroendocrine-immunoregulatory network plays a principal role in adapting to salinity changes as the main center for sensing the stress and causes immune response in L. vannamei.
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Inmunidad Innata/inmunología , Penaeidae/fisiología , Salinidad , Animales , Inmunidad Innata/efectos de los fármacos , Sistemas Neurosecretores/efectos de los fármacos , Sistemas Neurosecretores/inmunología , Sistemas Neurosecretores/fisiología , Penaeidae/efectos de los fármacos , Penaeidae/inmunología , Cloruro de Sodio/farmacología , Estrés Fisiológico/efectos de los fármacosRESUMEN
The white shrimp Litopenaeus vannamei has been greatly impacted by low salinity stress. To gain knowledge on the immune response in L. vannamei under such stress, we investigated digital gene expression (DEG) in L. vannamei hemocytes using the deep-sequencing platform Illumina HiSeq 2000. In total, 38,155 high quality unigenes with average length 770 bp were generated; 145 and 79 genes were identified up- or down-regulated, respectively. Functional categorization and pathways of the differentially expressed genes revealed that immune signaling pathways, cellular immunity, humoral immunity, apoptosis, cellular protein synthesis, lipid transport and energy metabolism were the differentially regulated processes occurring during low salinity stress. These results will provide a resource for subsequent gene expression studies regarding environmental stress and a valuable gene information for a better understanding of immune mechanisms of L. vannamei under low salinity stress.
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Proteínas de Artrópodos/genética , Hemocitos/inmunología , Inmunidad Innata , Penaeidae/fisiología , Transcriptoma , Animales , Proteínas de Artrópodos/metabolismo , Biblioteca de Genes , Hemocitos/metabolismo , Secuenciación de Nucleótidos de Alto Rendimiento , Penaeidae/genética , Penaeidae/inmunología , Distribución Aleatoria , Salinidad , Estrés FisiológicoRESUMEN
The hydrophobin EAS from the fungus Neurospora crassa forms functional amyloid fibrils called rodlets that facilitate spore formation and dispersal. Self-assembly of EAS into fibrillar rodlets occurs spontaneously at hydrophobic:hydrophilic interfaces and the rodlets further associate laterally to form amphipathic monolayers. We have used site-directed mutagenesis and peptide experiments to identify the region of EAS that drives intermolecular association and formation of the cross-ß rodlet structure. Transplanting this region into a nonamyloidogenic hydrophobin enables it to form rodlets. We have also determined the structure and dynamics of an EAS variant with reduced rodlet-forming ability. Taken together, these data allow us to pinpoint the conformational changes that take place when hydrophobins self-assemble at an interface and to propose a model for the amphipathic EAS rodlet structure.
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Amiloide/metabolismo , Hongos/metabolismo , Secuencia de Aminoácidos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Microscopía Electrónica de Transmisión , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Homología de Secuencia de AminoácidoRESUMEN
In the present study of the swimming crab Portunus trituberculatus exposed to 0, 1, and 5 mg L(-1) NH4Cl, the effects of ammonia exposure on ammonia and urea content in hemolymph; activity of H(+)-ATPase (subunit A) and Na(+)/K(+)-ATPase (α-subunit) (NKA) in gills; mRNA expression levels of the crustacean Rh-like ammonia transporter (Rh), K(+) Channel, Na(+)/K(+)/2Cl(-) co-transporter (NKCC), Na(+)/H(+)-exchanger (NHE), urea transporter (UT) and vesicle associated membrane protein (VAMP) in gills were investigated. The ultrastructure of gills was also evaluated. All these results in this study showed a dose-dependent effect with ammonia exposure concentration. The data displayed a significant increase in hemolymph ammonia and urea concentrations under ammonia exposure. The up-regulation of Rh mRNA together with up-regulation of K(+)-channel mRNA, NKA activity, down-regulation of NKCC and NHE mRNA suggested a coordinated protective response to maintain a relatively low ammonia concentration in the body fluids during ambient ammonia exposure. The up-regulation of VAMP, H(+)-ATPase activity along with the ultrastructure of gills suggested a mechanism of exocytotic ammonia excretion that may exit in the gill of P. trituberculatus. An increased production of urea and the up-regulated expression of UT suggested that the crab can detoxify elevated ammonia levels in the body fluids into urea when pathways of ammonia excretion are decreased after long term ammonia exposure.
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Amoníaco/metabolismo , Crustáceos/metabolismo , Nitrógeno/administración & dosificación , Urea/metabolismo , Animales , Exposición a Riesgos Ambientales , Branquias/metabolismo , Hemolinfa/metabolismo , Microtúbulos/metabolismoRESUMEN
Continuous monoculture of Lanzhou lily (Lilium davidii var. unicolor Cotton) results in frequent incidence of fusarium wilt caused by Fusarium oxysporum. Phthalic acid (PA), a principal autotoxin from root exudates of Lanzhou lily, is involved in soil sickness by inducing autotoxicity. The aim of this study was to evaluate the direct allelopathic effects of PA on the growth, development and pathogenicity of F. oxysporum in vitro based on an ecologically relevant soil concentration. The results showed that PA slightly but not significantly inhibited the colony growth (mycelial growth) and fungal biomass of F. oxysporum at low concentrations ranging from 0.05 to 0.5 mM, and significantly inhibited the colony growth at the highest concentration (1 mM). None of the PA concentrations tested significantly inhibited the conidial germination and sporulation of F. oxysporum in liquid medium. However, mycotoxin (fusaric acid) yield and pathogenesis-related hydrolytic enzyme (protease, pectinase, cellulase, and amylase) activities were significantly stimulated in liquid cultures of F. oxysporum containing PA at ≥ 0.25 mM. We conclude that PA at a soil level (i.e. 0.25 mM) is involved in plant-pathogen allelopathy as a stimulator of mycotoxin production and hydrolytic enzyme activities in F. oxysporum, which is possibly one of the mechanisms responsible for promoting the wilt disease of lily.
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Fusarium/crecimiento & desarrollo , Fusarium/patogenicidad , Lilium/química , Ácidos Ftálicos/farmacología , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo , Fusarium/efectos de los fármacos , Lilium/metabolismo , Lilium/microbiología , Ácidos Ftálicos/metabolismo , Enfermedades de las Plantas/microbiología , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Esporas Fúngicas/patogenicidad , Virulencia/efectos de los fármacosRESUMEN
Hydrophobins are fungal proteins that self-assemble spontaneously to form amphipathic monolayers at hydrophobic:hydrophilic interfaces. Hydrophobin assemblies facilitate fungal transitions between wet and dry environments and interactions with plant and animal hosts. NC2 is a previously uncharacterized hydrophobin from Neurospora crassa. It is a highly surface active protein and is able to form protein layers on a water:air interface that stabilize air bubbles. On a hydrophobic substrate, NC2 forms layers consisting of an ordered network of protein molecules, which dramatically decrease the water contact angle. The solution structure and dynamics of NC2 have been determined using nuclear magnetic resonance spectroscopy. The structure of this protein displays the same core fold as observed in other hydrophobin structures determined to date, including the Class II hydrophobins HFBI and HFBII from Trichoderma reesei, but certain features illuminate the structural differences between Classes I and II hydrophobins and also highlight the variations between structures of Class II hydrophobin family members. The unique properties of hydrophobins have attracted much attention for biotechnology applications. The insights obtained through determining the structure, biophysical properties and assembly characteristics of NC2 will facilitate the development of hydrophobin-based applications.
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Proteínas Fúngicas/química , Neurospora crassa , Secuencia de Aminoácidos , Proteínas Fúngicas/ultraestructura , Interacciones Hidrofóbicas e Hidrofílicas , Microscopía de Fuerza Atómica , Modelos Moleculares , Datos de Secuencia Molecular , Resonancia Magnética Nuclear Biomolecular , Multimerización de Proteína , Estructura Cuaternaria de Proteína , Soluciones , Propiedades de Superficie , Tensoactivos/químicaRESUMEN
Positron emission tomography (PET) is a highly sensitive quantitative imaging technique for studying molecular pathways and interactions in vivo. This imaging technique plays a key role in drug discovery, pharmacokinetics, pharmacodynamics, and assessing in vivo distribution. In this study, we designed an ethynylbenzene-substituted glycol (M(E)) as a versatile probe for PET labeling of oligonucleotides through a click reaction.
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Acetileno/análogos & derivados , Glicoles/química , Sondas Moleculares/síntesis química , Oligonucleótidos/química , Acetileno/química , Química Clic , Glicoles/síntesis química , Sondas Moleculares/química , Oligonucleótidos/síntesis química , Tomografía de Emisión de Positrones , Estereoisomerismo , TemperaturaRESUMEN
BACKGROUND: Activated hepatic stellate cells are the main source of excessive collagen deposition in liver fibrosis. Here we report the inhibitory effects of the combinational treatment of two natural products, astragalus polysaccharide (APS) and ß-elemene (ELE) on the activation of human liver hepatic stellate cell line LX-2 cells. METHODS: Cultured LX-2 cells were treated with different concentrations of APS or ELE for 24 or 48 hours. Cell viability/apoptosis was measured by MTT assay and Annexin V/PI staining , activation related genes including α-SMA and CD44 expressions were measured by real-time PCR and western blot respectively. RESULTS: The majority of LX-2 cells showed morphological change in the presence of APS or ELE for 24 hours. Treatment with APS + ELE for 24 or 48 hours significantly inhabited the cell proliferation compared with APS or ELE treatment alone on LX-2 cells. APS + ELE may block the up-regulation of α-SMA and CD44 both in mRNA and protein levels through TGF-ß pathway in LX-2 cells. CONCLUSION: APS or ELE treatment alone on LX-2 cells could inhibit cell proliferation and induce apoptosis. The combinational treatment using APS + ELE significantly increased the killing efficiency on LX-2 cells. α-SMA and CD44 expressions was inhibited upon APS + ELE treatment through TGF-ß pathway in LX-2 cells. The results indicated a novel treatment using natural products for liver diseases with anti-fibrotic effect.
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Apoptosis/efectos de los fármacos , Planta del Astrágalo , Proliferación Celular/efectos de los fármacos , Células Estrelladas Hepáticas/efectos de los fármacos , Cirrosis Hepática/tratamiento farmacológico , Polisacáridos/farmacología , Sesquiterpenos/farmacología , Actinas/metabolismo , Línea Celular , Supervivencia Celular/efectos de los fármacos , Humanos , Receptores de Hialuranos/metabolismo , Cirrosis Hepática/patología , Factor de Crecimiento Transformador beta1/metabolismo , Regulación hacia ArribaRESUMEN
Antisense oligonucleotides (ASOs) are generally obtained via chemical synthesis on a solid support and phosphorothioate (PS) modification with a phosphate backbone to increase their in vivo stability and activity. However, desulphurised products, in which PS is partially replaced by phosphodiesters, are generally formed during the chemical synthesis of ASO and are difficult to separate from the desired PS-modified ASO by chromatography. Therefore, revealing the unknown factors that cause the formation of desulphurised products and proposing methods to inhibit their formation are highly desirable. In this study, it was found that peroxides in THF, which is used as a solvent for the acetyl capping agent, oxidise phosphite triesters to produce desulphurisation products. The use of THF with antioxidants effectively suppresses the oxidation caused by THF peroxides. Moreover, THF peroxide was found to oxidise phosphoramidites, which are the building blocks of oligonucleotide chemical syntheses, indicating that caution should be taken with the organic solvents used during the synthesis and purification of phosphoramidites.
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We used tomato genotypes deficient in the jasmonic acid (JA) pathway to study the interaction between the production of herbivore-induced plant volatiles (HIPVs) that serve as information cues for herbivores as well as natural enemies of herbivores, and the production of foliar trichomes as defence barriers. We found that jasmonic acid-insensitive1 (jai1) mutant plants with both reduced HIPVs and trichome production received higher oviposition of adult leafminers, which were more likely to be parasitized by the leafminer parasitoids than JA biosynthesis spr2 mutant plants deficient in HIPVs but not trichomes. We also showed that the preference and acceptance of leafminers and parasitoids to trichome-removed plants from either spr2 or wild-type (WT) genotypes over trichome-intact genotypes can be ascribed to the reduced trichomes on treated plants, but not to altered direct and indirect defence traits such as JA, proteinase inhibitor (PI)-II and HIPVs levels. Although the HIPVs of WT plants were more attractive to adult insects, the insects preferred trichome-free jai1 plants for oviposition and also had greater reproductive success on these plants. Our results provide strong evidence that antagonism between HIPV emission and trichome production affects tritrophic interactions. The interactions among defence traits are discussed.
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Herbivoria/fisiología , Insectos/fisiología , Hojas de la Planta/anatomía & histología , Hojas de la Planta/fisiología , Solanum lycopersicum/fisiología , Solanum lycopersicum/parasitología , Compuestos Orgánicos Volátiles/metabolismo , Animales , Ciclopentanos/metabolismo , Ciclopentanos/farmacología , Genotipo , Herbivoria/efectos de los fármacos , Interacciones Huésped-Parásitos/efectos de los fármacos , Solanum lycopersicum/efectos de los fármacos , Solanum lycopersicum/inmunología , Mutación/genética , Odorantes/análisis , Oxilipinas/metabolismo , Oxilipinas/farmacología , Hojas de la Planta/efectos de los fármacosRESUMEN
The fungal hydrophobins are small proteins that are able to spontaneously self-assemble into amphipathic monolayers at hydrophobic:hydrophilic interfaces. These protein monolayers can reverse the wettability of a surface, making them suitable for increasing the biocompatibility of many hydrophobic materials. The self-assembling properties and amphipathic nature of hydrophobins make them attractive candidates for biotechnological applications. Recently, there have been significant advances in the understanding of the structure and assembly of these remarkable proteins. This opens up the way for engineering these proteins to encompass novel functions and for the use of hydrophobins in modification of nanomaterials. This review highlights the important structural aspects of the hydrophobins and the mechanisms by which they assemble and describes recent exciting developments in the use of hydrophobins for cell attachment, drug delivery, and protein purification.
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Proteínas Fúngicas , Hongos , Interacciones Hidrofóbicas e Hidrofílicas , Nanoestructuras , Propiedades de Superficie , HumectabilidadRESUMEN
Class I fungal hydrophobins are small surface-active proteins that self-assemble to form amphipathic monolayers composed of amyloid-like rodlets. The monolayers are extremely robust and can adsorb onto both hydrophobic and hydrophilic surfaces to reverse their wettability. This adherence is particularly strong for hydrophobic materials. In this report, we show that the class I hydrophobins EAS and HYD3 can self-assemble to form a single-molecule thick coating on a range of nanomaterials, including single-walled carbon nanotubes (SWCNTs), graphene sheets, highly oriented pyrolytic graphite, and mica. Moreover, coating by class I hydrophobin results in a stable, dispersed preparation of SWCNTs in aqueous solutions. No cytotoxicity is detected when hydrophobin or hydrophobin-coated SWCNTs are incubated with Caco-2 cells in vitro. In addition, we are able to specifically introduce covalently linked chemical moieties to the hydrophilic side of the rodlet monolayer. Hence, class I hydrophobins provide a simple and effective strategy for controlling the surfaces of a range of materials at a molecular level and exhibit strong potential for biomedical applications.