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Strengthening the interfacial contact between the reactive components effectively boosts the energy release of energetic materials. In this study, we aimed to create a close-knit interfacial contact condition between aluminum nanoparticles (Al NPs) and Polyvinylidene fluoride-hexafluoropropylene (P(VDF-HFP)) through hydrolytic adsorption and assembling 1H, 1H, 2H, 2H-Perfluorododecyltrichlorosilane (FTCS) on the surface of Al NPs. Leveraging hydrogen bonding between -CF and -CH and the interaction between C-Fâ¯F-C groups, the adsorbed FTCS directly leads to the growth of the P(VDF-HFP) coating layer around the treated Al NPs, yielding Al@FTCS/P(VDF-HFP) energetic composites. In comparison with the ultrasonically processed Al/P(VDF-HFP) mixture, thermal analysis reveals that Al@FTCS/P(VDF-HFP) exhibits a 57 °C lower reaction onset temperature and a 1646 J/g increase in heat release. Associated combustion tests demonstrate a 52% shorter ignition delay, 62% shorter combustion time, and a 288% faster pressurization rate. These improvements in energetic characteristics stem from the reactivity activation of FTCS towards Al NPs by the etching effect to the surface Al2O3. Moreover, enhanced interfacial contact facilitated by the FTCS-directed growth of P(VDF-HFP) around Al NPs further accelerates the whole reaction process.
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OBJECTIVE: This study aimed to explore the characteristics of carbapenem-resistant Enterobacterales (CRE) patients in the intensive care unit (ICU) in different regions of Henan Province to provide evidence for the targeted prevention and treatment of CRE. METHODS: This was a cross-sectional study. CRE screening was conducted in the ICUs of 78 hospitals in Henan Province, China, on March 10, 2021. The patients were divided into provincial capital hospitals and nonprovincial capital hospitals for comparative analysis. RESULTS: This study involved 1009 patients in total, of whom 241 were CRE-positive patients, 92 were in the provincial capital hospital and 149 were in the nonprovincial capital hospital. Provincial capital hospitals had a higher rate of CRE positivity, and there was a significant difference in the rate of CRE positivity between the two groups. The body temperature; immunosuppressed state; transfer from the ICU to other hospitals; and use of enemas, arterial catheters, carbapenems, or tigecycline at the provincial capital hospital were greater than those at the nonprovincial capital hospital (P < 0.05). However, there was no significant difference in the distribution of carbapenemase strains or enzymes between the two groups. CONCLUSIONS: The detection rate of CRE was significantly greater in provincial capital hospitals than in nonprovincial capital hospitals. The source of the patients, invasive procedures, and use of advanced antibiotics may account for the differences. Carbapenem-resistant Klebsiella pneumoniae (CR-KPN) was the most prevalent strain. Klebsiella pneumoniae carbapenemase (KPC) was the predominant carbapenemase enzyme. The distributions of carbapenemase strains and enzymes were similar in different regions.
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Antibacterianos , Temperatura Corporal , Humanos , Estudos Transversais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Cânula , Carbapenêmicos/farmacologia , Klebsiella pneumoniaeRESUMO
Fungal pathogens typically use secreted effector proteins to suppress host immune activators to facilitate invasion. However, there is rarely evidence supporting the idea that fungal secretory proteins contribute to pathogenesis by transactivating host genes that suppress defense. We previously found that pathogen Magnaporthe oryzae induces rice Bsr-d1 to facilitate infection and hypothesized that a fungal effector mediates this induction. Here, we report that MoSPAB1 secreted by M. oryzae directly binds to the Bsr-d1 promoter to induce its expression, facilitating pathogenesis. Amino acids 103-123 of MoSPAB1 are required for its binding to the Bsr-d1 promoter. Both MoSPAB1 and rice MYBS1 compete for binding to the Bsr-d1 promoter to regulate Bsr-d1 expression. Furthermore, MoSPAB1 homologues are highly conserved among fungi. In particular, Colletotrichum fructicola CfSPAB1 and Colletotrichum sublineola CsSPAB1 activate kiwifruit AcBsr-d1 and sorghum SbBsr-d1 respectively, to facilitate pathogenesis. Taken together, our findings reveal a conserved module that may be widely utilized by fungi to enhance pathogenesis.
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Ascomicetos , Magnaporthe , Oryza , Oryza/genética , Magnaporthe/genética , Ascomicetos/metabolismo , Transporte Biológico , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismoRESUMO
The discovery of chiral carbon dots (Ch-CDs) has opened up an exciting new research direction in the field of carbon dots. It not only retains the chirality of the precursor and exhibits highly symmetric chiral optical properties but also has properties such as chemical stability, antibacterial and antitumor properties, and good biocompatibility of carbon dots. Based on these advantages, the application of Ch-CDs in the biomedical field has attracted significant interest among researchers. However, a comprehensive review of the selection of precursors for Ch-CDs, preparation methods, and applications in biomedical fields is still lacking. Here, we summarize their precursor selection and preparation methods based on recent reports on Ch-CDs and provide the first comprehensive review for specific applications in biomedical engineering, such as biosensing, bioimaging, drug carriers, antibacterial and antibiofilm, and enzyme activity modulation. Finally, we discuss application prospects and challenges that need to be overcome. We hope this review will provide valuable guidance for researchers to prepare novel Ch-CDs and facilitate their application in biomedical engineering.
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Pontos Quânticos , Pontos Quânticos/uso terapêutico , Pontos Quânticos/química , Carbono/química , Portadores de Fármacos , Engenharia Biomédica , Antibacterianos/farmacologia , Antibacterianos/uso terapêuticoRESUMO
We proposed and numerically studied a traceless encryption approach for physical layer security in coherent optical communications system, the most attractive advantage of which is that it is hard for eavesdroppers to be aware that the transmission signal has been encrypted because the modulation formats of encrypted signal are still the regular ones, i.e. traceless encryption. In the proposed approach, the phase only or the combination of phase and amplitude dimensions can be used for encryption and decryption. Three simple encryption rules are designed and used to investigate the encryption security performance of the scheme, in which the QPSK signal can be encrypted to be as 8PSK, QPSK and 8QAM. The results show that three simple encryption rules can cause 37.5%, 25%, 62.5% of user signal binary codes to be misinterpreted by the eavesdroppers, respectively. When the modulation formats of encrypted signal and user signal are identical, the scheme can not only cover up the real information, but also have a potential application at misleading eavesdroppers. The impacts of the control light peak power at the receiver on the decryption performance are also analysed, the results indicate that the decryption performance of the scheme has a good tolerance to the peak power fluctuation of control light at the receiver.
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Soybean (Glycine max L.) is one of the important oilseed and vegetable crop worldwide and provides the main source of vegetable oil and proteins for human and livestock (Hartman et al. 2011). In October 2021, approximately 35% of soybean pods suffered from anthracnose in the farmer's field in Chongzhou, Sichuan Province, China (103°40'12"E, 30°37'48"N), and the occurrence area accounted for about 3.3 hm2. Symptoms of soybean were characterized by yellow spots at the initial stage, gradually expanded into dark brown spots, and eventually amounts of small black particles were densely arranged in the wheel shape on dead spots. Diseased spots of soybean pods were cut into pieces and sequentially sterilized in 75% alcohol for 30 s, 4% sodium hypochlorite for 30 s, sterile water for 3 times. After that, these pieces were placed on potato dextrose agar (PDA), and incubated at 25±2°C in the dark for 5-7 days. Single spore was separately picked and transferred to a fresh PDA plate to obtain pure culture isolates. Total six pure isolates were collected, and among them the hyphae of representative isolate 8-B were initially white, turned grey gradually on PDA medium, and the colonial reverse were radiating, whorled or a mixture of both. Conidia of 8-B were septate, hyaline, unicellular, cylindrical, obtusely rounded at both ends with 1 or 2 oil balls inside, and 10.5-17.6 µm in length and 7.0 µm-3.6 µm in width (n=100). The conidial appressoria were brown subspherical, 6.9 µm-13.3 µm in length and 5.6 µm-10.1 µm (n=50) in width. Based on morphological and cultural characteristics, the isolate 8-B was tentatively identified as Colletotrichum gloeosporioides species complexï¼Weir et al. 2012). To test pathogenicity, the mycelial plugs were inoculated on 20 detached soybean pods at full seed (R6) stage, and three areas of each pod were lightly scratched using a needle prior to inoculation. As controls, the PDA plugs were attached to the pinned-treated pods. Three independent replicates were conducted for control and inoculated pods, respectively. All pods were incubated in a greenhouse at 25 ± 2°C with a relative humidity of approximately 90%. After 4-5 days post-inoculation, typical anthracnose lesions were observed on the inoculated pods while the control pods remained healthy only with small wound spots. The pathogen re-isolated from all the inoculated pods were morphologically identical to the inoculation isolate (8-B). For further molecular verification, the six gene fragments including the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), actin (ACT), ß-tubulin 2 (TUB2) and calmodulin (CAL) were amplified and sequenced (Weir et al. 2012, Damm et al. 2012), and the obtained sequences were deposited in GenBank (Accession numbers ON960278, ON685214, ON964475, ON974476, ON685215 and ON964477, respectively). All six gene sequences of 8-B had a high identity to C. fructicola (the stand isolate ICMP 18581) with the accession numbers ON960278 (100%), ON974476 (96%), ON685214 (99%), ON964475 (99%), ON685215 (100%), and ON964477 100%), respectively. Anthracnose disease caused by C. fructicola has previously been reported to affect a range of plant hosts worldwide (Guarnaccia et al. 2017). However, it is still unknown on C. fructicola causing anthracnose in soybean in China. This study firstly reports C. fructicola as the causal agent of anthracnose on soybean in the country, and provides a theoretical basis for the diagnosis and control of this disease.
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We propose a novel, to the best of our knowledge, 1×5 broadband power splitter based on the photonic crystal. The Powell algorithm is used to reverse-design the proposed broadband power splitter. The results show that the transmittance of each output port of the broadband photonic crystal power splitter can be adjusted by changing the radii and offsets of the dielectric rods at the junction area of each waveguide. According to the target splitting ratio, the reverse design of the structural parameters using the Powell algorithm significantly improves the optimization efficiency and splitting performance of the broadband power splitter. The designed power splitters have a wide working bandwidth of 1525-1565 nm, a flexible and designable power splitting ratio, excellent splitting performance, and a compact size, which have great application prospects in all-optical communication networks, high-density photon integration, and other fields.
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Due to the increasing bacterial resistance to conventional antibiotics, developing safe and effective approaches to combat infections caused by bacteria and biofilms has become an urgent clinical problem. Recently, carbon dots (CDs) have received great attention as a promising alternative to conventional antimicrobial agents due to their excellent antimicrobial efficacy and biocompatibility. Although CDs have been widely used in the field of antibacterial applications, their antibacterial and antibiofilm mechanisms have not been systematically discussed. This review provides a systematic overview on the complicated mechanisms of antibacterial and antibiofilm CDs based on recent development.
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Anti-Infecciosos , Carbono , Antibacterianos/farmacologia , Bactérias , Biofilmes , Carbono/farmacologiaRESUMO
Sex-determination pathways are extremely diverse. Understanding the mechanism of sex determination in insects is important for genetic manipulation of the pest population and for breeding of economically valuable insects. Although sex determination has been well characterized in the model species Drosophila melanogaster, little is known about this pathway in Stratiomyidae. In the present study, we first identified the Drosophila intersex (ix) homolog in Hermetia illucens, also known as the black soldier fly, which belongs to the Stratiomyidae family and which is an important insect for the conversion of various organic wastes. Phylogenetic analyses and multiple sequence alignment revealed that Hiix is conserved compared with Drosophila. We showed that Hiix is highly expressed in internal genitalia. Disruption of the Hiix gene using CRISPR/Cas9 resulted in female-specific defects in external genitalia and abnormal and undersized ovaries. Taken together, our study furthers our understanding of sex determination in insects and could facilitate breeding of H. illucens.
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Dípteros , Drosophila melanogaster , Feminino , Animais , Larva , Filogenia , Dípteros/genética , DrosophilaRESUMO
Blueberry leaf spots and stem cankers caused by Pestalotiopsis spp. have become a serious threat for the production of blueberry in Sichuan Province. To characterize the etiology of the diseases connected with these fungi, samples showing leaf spot and stem canker symptoms were collected from the 12 main blueberry-growing areas of Sichuan Province from 2015 to 2020 and used for pathogen isolation. In total, 91 fungal isolates were obtained with preliminary morphological identification and 48 representative strains were selected for further pathogenicity test and molecular identification. Four species, including Pestalotiopsis clavispora (Neopestalotiopsis clavispora) (57.14%), P. trachicarpicola (28.57%), P. chamaeropis (13.19%), and P. adusta (1.10%), were identified based on conidial morphology, cultural characteristics, and phylogenetic analysis of the internal transcribed spacer region, partial sequence of the ß-tubulin gene, and the translation elongation factor 1-α. Pathogenicity tests showed that four species were pathogenic to leaves and stems of blueberry. Among them, P. clavispora (N. clavispora) was the most aggressive as the predominant species to cause both leaf spot and stem canker. P. trachicarpicola and P. chamaeropis were mainly isolated from leaves but also pathogenic to stems. P. adusta was only isolated from stems but also pathogenic to leaves. To the best of our knowledge, this is the first report of P. chamaeropis and P. adusta as pathogens causing leaf spots and stem canker on blueberry. The results provide helpful information in disease diagnosis and management of blueberry.
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Mirtilos Azuis (Planta) , Pestalotiopsis , Filogenia , ChinaRESUMO
H. Mutabilis (Cotton rose or confederate rose) is a deciduous shrub in the Malvaceae family, with ornamental, medicinal and edible values (Fan et al. 2015). In May to August 2020, 40.4% of potted plants of H. mutabilis were found to have root and stalk rot in Chengdu Botanical Garden (E104°7'28â³, N30°45'57â³). At first the leaves of affected H. mutabilis turned yellow and wilted, followed by the stem and root cortex became dark brown and rotten. Finally, the whole plant died within two months. Root and stem produced white mycelium when the humidity exceeded 90%. Samples taken from the lesions were surface disinfested for 3 min in 4% sodium hypochlorite, rinsed in sterile water and plated on potato dextrose agar (PDA), 35 single-spore cultures with similar morphology isolated from symptomatic tissues were obtained and subcultured. After seven days at 25°C in the dark, the mycelium of a representative culture MFR1 covered the entire plate surface (9 cm diameter). The aerial mycelium of cultures were white and fluffy at first and produced lavender pigment on the back of the cultures in the later stage. After seven days, the cultures produced abundant sickle-shaped macroconidia which have 3 to 5 septations and some oval or oblong microconidia which have 0 to 1 septation. Macroconidia 22.35~46.67 µm (mean 32.11 µm) in length and 4.32~7.72 µm (mean 5.21 µm) in width (n = 100). Microconidia 7.10~21.85 µm (mean 11.62 µm) in length and 2.76~6.84 µm (mean 4.20 µm) in width (n = 100). Based on these characteristics, isolates were tentatively identified as Fusarium sp. (Crous et al. 2021). Pathogenicity was tested on 1-year-old potted seedlings of H. mutabilis by root-zone irrigation inoculation in Sichuan Agricultural University (Jia et al.2019). Conidia suspension (1×107conidia/mL,collected from MFR1 )was poured into the soil along the plant roots. The same amount of distilled water was poured around the roots of the control plants. All inoculated and control plants were incubated in the greenhouse (about 25 ± 2°C). The experiment was performed three times. Within 25 days after inoculation, all plants inoculated with pathogens showed symptoms similar to those in the field, whereas the controls remained symptomless. The pathogen was reisolated from all inoculated plants, and the cultural and morphological characteristics were the same as those of the original isolate. After DNA extraction and PCR amplification, the translation elongation factor 1-alpha (TEF) and RNA polymerase II second largest subunit (RPB2) genes of a representative culture MFR1, were sequenced (O'Donnell et al. 2010) and deposited in GenBank (accession numbers OK334295 and ON316728, respectively). The TEF and RPB2 sequences were 99.7% and 99.39% identical to those of F. oxysporum (MN892354 and MZ198892). The result was confirmed by multilocus phylogenetic analysis. Through morphological identification and molecular analyses, the pathogen was identified as F. oxysporum. F. oxysporum is known to infect cotton (Dowd et al.2004), soybean (Ellis et al.2016) and banana (Fourie et al.2011) among other hosts, but it is the first report of F. oxysporum infecting H. mutabilis in China or worldwide. This disease seriously reduced the survival rate of H. mutabilis and may become an important reason to hinder the increase of H. mutabilis in potted seedlings stage. Moreover, the findings will provide theoretical basis to solve the bottleneck problem affecting the popularization and propagation of H. mutabilis.
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It is very challenging to design nanomaterials with both excellent antibacterial activity and cytocompatibility when facing bacterial infection. Here, inspired by antimicrobial peptides (AMPs), we fabricate carbon quantum dots (CQDs) derived from hydrophobic tryptophan and hydrophilic lysine or arginine (Lys/Trp-CQDs and Arg/Trp-CQDs), which possess amphipathic properties. These CQDs could effectively destroy bacterial membranes without developing resistance, inhibit biofilms formed by Staphylococcus aureus, and exhibit good in vitro biocompatibility. The antibacterial activities are caused by not only surface cationic structures and excess intracellular reactive oxygen species (ROS) generated by the CQDs but also the effects of the surface hydrophobic groups. These combined mechanisms of actions lead to bacterial membrane disruption, which raises the hope for combating bacterial infection without concern about drug resistance. What's more, the effect of amphiphilicity on balancing sterilization with biocompatibility expands the research ideas for developing available antibacterial nanomaterials.
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Pontos Quânticos , Infecções Estafilocócicas , Antibacterianos/farmacologia , Bactérias , Biofilmes , Carbono/farmacologia , Resistência a Medicamentos , Humanos , Pontos Quânticos/toxicidadeRESUMO
AIMS: This study investigated the effects of adipose-derived stem cell sheets on a rat model of detrusor underactivity. MAIN METHODS: Adipose-derived stem cell sheets were prepared from the subcutaneous adipose tissue of male Lewis rats. Female Lewis rats were assigned into four groups: control, sham operation, cryo-injury, and cryo-injury+sheet (n = 8 per group). Rats in the cryo-injury+sheet group were implanted with ASC sheets 3 days after cryo-injury induction and underwent cystometry 7 days later. Subsequently, reverse transcription-polymerase chain reaction (RT-PCR) and histopathological examinations were performed. Cell sheets expressing the green fluorescent protein were prepared and transplanted to confirm the viability and differentiation of the sheets. Fluorescence was confirmed using a fluorescence stereomicroscope on days 3, 7, 14, 21, and 28 after sheet implantation, and tissue immunostaining was performed. KEY FINDINGS: Cystometry showed that sheet implantation improved the maximum intravesical pressure (P = 0.009) and the residual urine volume (P = 0.011). Furthermore, RT-PCR indicated that the mRNA levels of the angiogenic factors vascular endothelial growth factor and hepatocyte growth factor were significantly higher in the cryo-injury+sheet group than in the cryo-injury group (P = 0.045, P = 0.037, respectively). Histologically, sheet implantation resulted in an improvement in inflammation and increased the number of blood vessels. Green fluorescent protein-positive cells fused with von Willebrand factor-positive cells and differentiated into blood vessels 7 days after sheet implantation. SIGNIFICANCE: Adipose-derived stem cell sheets transplanted into the bladder of cryo-injured rats differentiated into blood vessels and restored bladder contractile function 7 days after transplantation.
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Bexiga Inativa , Tecido Adiposo , Animais , Feminino , Proteínas de Fluorescência Verde , Masculino , Ratos , Ratos Endogâmicos Lew , Transplante de Células-Tronco/métodos , Células-Tronco , Fator A de Crescimento do Endotélio VascularRESUMO
Bacterial infection and excessive reactive oxygen species (ROS) remain challenging factors contributing to the delayed healing of chronic wounds. Although various antibacterial and antioxidant hydrogel dressings have been developed to accelerate wound healing, multifunctional hydrogels fabricated by rationally designing and introducing carbonized polymer dots (CPDs) have rarely been reported. Herein, inspired by the mussel biomimetic approach, we synthesized 3,4-dihydroxybenzaldehyde functionalized chitosan (DFC), and then the polymeric precursor was pyrolyzed into CPDs with abundant amino and catechol groups on the surface, which endowed it with a highly positively charged surface that could activate the photothermal effect under near-infrared (NIR) light irradiation. Finally, the nanocomposite hydrogel (PVA@CPDs) was simply constructed by directly mixing polyvinyl alcohol (PVA) with CPDs, utilizing the freeze-thaw cycle method to form a gel, in which, CPDs as a center of polyfunctional nanoparticles drove the formation of PVA microcrystalline crosslinking and endowed the PVA substrate with versatile functionalities. Remarkable and comprehensive improvements in the swelling behavior, mechanical properties and adhesive strength of the hydrogel could be conveniently achieved with the suitable loading of CPDs. The in vitro experiments demonstrated that the PVA@CPDs hydrogel presented broad-spectrum and rapid bactericidal activity, concurrently acting as an effective antioxidant being able to scavenge free radicals. In addition, no obvious cytotoxicity was observed for the multifunctional hydrogel after incubation with L02 cells. In vivo evaluation in an infected full-thickness skin wound model demonstrated that the PVA@CPDs hydrogel promoted wound closure without any side effects. As a consequence, the current work manifests a facile yet versatile strategy to develop effective and biocompatible multifunctional hydrogel dressings for bacteria-infected wound healing.
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Quitosana , Infecção dos Ferimentos , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Bandagens , Catecóis/farmacologia , Quitosana/química , Humanos , Hidrogéis/química , PolímerosRESUMO
BACKGROUND: Gout is usually found in patients with atrial fibrillation (AF). K+ efflux is a common trigger of NLRP3 inflammasome activation which is involved in the pathogenesis of AF. We investigated the role of the K+ channel Kv1.5 in monosodium urate crystal (MSU)-induced activation of the NLRP3 inflammasome and electrical remodeling in mouse and human macrophages J774.1 and THP-1, and mouse atrial myocytes HL-1. METHODS AND RESULTS: Macrophages, primed with lipopolysaccharide (LPS), were stimulated by MSU. HL-1 cells were incubated with the conditioned medium (CM) from MSU-stimulated macrophages. Western blot, ELISA and patch clamp were used. MSU induced caspase-1 expression in LPS-primed J774.1 cells and IL-1ß secretion, suggesting NLRP3 inflammasome activation. A selective Kv1.5 inhibitor, diphenyl phosphine oxide-1 (DPO-1), and siRNAs against Kv1.5 suppressed the levels of caspase-1 and IL-1ß. MSU reduced intracellular K+ concentration which was prevented by DPO-1 and siRNAs against Kv1.5. MSU increased expression of Hsp70, and Kv1.5 on the plasma membrane. siRNAs against Hsp70 were suppressed but heat shock increased the expression of Hsp70, caspase-1, IL-1ß, and Kv1.5 in MSU-stimulated J774.1 cells. The CM from MSU-stimulated macrophages enhanced the expression of caspase-1, IL-1ß and Kv1.5 with increased Kv1.5-mediated currents that shortened action potential duration in HL-1 cells. These responses were abolished by DPO-1 and a siRNA against Kv1.5. CONCLUSIONS: Kv1.5 regulates MSU-induced activation of NLRP3 inflammasome in macrophages. MSUrelated activation of NLRP3 inflammasome and electrical remodeling in HL-1 cells are via macrophages. Kv1.5 may have therapeutic value for diseases related to gout-induced activation of the NLRP3 inflammsome, including AF.
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Remodelamento Atrial , Gota , Canal de Potássio Kv1.5/metabolismo , Animais , Caspase 1/metabolismo , Gota/tratamento farmacológico , Gota/metabolismo , Gota/patologia , Humanos , Inflamassomos/metabolismo , Interleucina-1beta/genética , Lipopolissacarídeos/farmacologia , Macrófagos/metabolismo , Camundongos , Miócitos Cardíacos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Ácido Úrico/metabolismo , Ácido Úrico/farmacologiaRESUMO
Podocarpus macrophyllus (Thunb.) D. Don is a perennial evergreen tree of the Podocarpaceae family, which is widely used in landscape, medicine and forest interplanting (Qin et al. 2021). In August 2020, approximately 10% of the leaves have expressed symptoms of anthracnose in the campus of Sichuan Agricultural University (E103°51'35.88â³, N30°42'30.41â³). The lesions were light brown small sunken spots on the leaf tip in the early stage, then spread along the petiole to expanded into larger, irregular gray-white lesions in the late stage, with sparse black dots arranged above. The edge of the lesion was obvious with a fine smooth dark brown line. Samples taken from the lesions were surface disinfected for 3 min in 4% sodium hypochlorite, rinsed in sterile water and plated on potato dextrose agar (PDA), Eight single-spore cultures isolates from 10 samples were obtained and subcultured. After five days at 25°C in the dark, the mycelium of a representative culture LJS1 covered the entire plate surface (9 cm diameter). Hyphae were initially white at first, and turned pale grayish in the later stage. After about 10 days, a large number of pink conidial mass were formed around the center. Conidia 14.7 - 18.6 µm (mean 16.2 µm) in length and 4.4 -7.1 µm (mean 5.8 µm) in width (n = 100), nonseptate, cylindrical, two ends round or one end slightly acute. Conidial appressoria 5.7 - 9.3 µm (mean 7.8 µm) in length and 4.4 - 7.9 µm (mean 6.2 µm) in width (n = 50), clavate, ovoid to slightly irregular. Based on these characteristics, isolates were tentatively identified as Colletotrichum siamense complex (Sharma et al. 2013). Pathogenicity tests were conducted by spraying a conidial suspension of LJS1 (1 × 107conidia/ml) to 10 wounded and 10 non-wounded leaves from P. macrophyllus plants. Two areas of cuticle on either side of the midrib of each leaf were wounded by lightly scratching with a needle prior to inoculation (Du et al. 2020). As a control, distilled water was sprayed onto an equal number of wounded and non-wounded leaves. All inoculated and control plants were incubated in greenhouse (about 25 ± 2°C). Lesions similar to those observed in the field appeared on all wounded inoculated leaves within eight days after inoculation, whereas the non-wounded inoculated leaves and the controls remained symptomless. Reisolations of the putative pathogen were confirmed through morphological characteristics and the representative culture LJS1 were confirmed to be the pathogenic agents. The internal transcribed spaces (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), gene spacer region between Apn2 and Mat1-2(ApMat) genes were sequenced (Sharma et al. 2013) and deposited in GenBank (accession numbers OK036793, OK067325 and OK086086 respectively). These sequences were highly identical to those of C. siamense Prihastuti, L. Cai & K.D. Hyde (culture LF 139): accession numbers KJ955087.1 (99%), KJ954788.1 (99%), KJ954503.1 (99%), respectively. Based on the morphology and our multi-locus approach, the pathogen was convincingly identified for the first time as C. siamense. However, there are no reports of C. siamense causing anthracnose on P. macrophyllus worldwide. The identification of the causal agent of the disease made clear the pathogen causing anthracnose on P. macrophyllus, and provide theoretical basis for the diagnosis and treatment of disease.
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Broadband optical frequency comb (OFC) generation based on a single electro-absorption modulator (EAM) is proposed. The EAM is driven by a radio frequency (RF) multi-frequency signal generated by a multiplication coupler composed of an electrical power splitter and an arithmetic circuit. Thus the number of comb-lines of the generated OFC can be increased. A complete theoretical model of OFC generation by an EAM driven by nth power of the RF source is established, and the performance of the OFC is analyzed by using OptiSystem software. The results show that, the number of comb-lines of the OFC is positively correlated with the number of multiplication of the RF source signal. The frequency spacing of the comb-lines is twice the frequency of the RF source signal and is tunable by adjusting the frequency of the RF source signal. Increasing chirp factor and modulation index of EAM could increase the number of comb-lines of the generated OFC. The amplitude of the RF source signal had little impact on the flatness of the OFC and the average OFC power. The scheme developed is not only simple and low-cost, but also can produce a large number of comb-lines.
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Cell-based therapy using adipose-derived stem cells (ADSCs) has emerged as a novel therapeutic approach to treat heart failure after myocardial infarction (MI). The purpose of this study was to determine whether inhibition of α1-adrenergic receptors (α1-ARs) in ADSCs attenuates ADSC sheet-induced improvements in cardiac functions and inhibition of remodeling after MI. ADSCs were isolated from fat tissues of Lewis rats. In in vitro studies using cultured ADSCs, we determined the mRNA levels of vascular endothelial growth factor (VEGF)-A and α1-AR under normoxia or hypoxia and the effects of norepinephrine and an α1-blocker, doxazosin, on the mRNA levels of angiogenic factors. Hypoxia increased α1-AR and VEGF mRNA levels in ADSCs. Norepinephrine further increased VEGF mRNA expression under hypoxia; this effect was abolished by doxazosin. Tube formation of human umbilical vein endothelial cells was promoted by conditioned media of ADSCs treated with the α1 stimulant phenylephrine under hypoxia but not by those of ADSCs pretreated with phenylephrine plus doxazosin. In in vivo studies using rats with MI, transplanted ADSC sheets improved cardiac functions, facilitated neovascularization, and suppressed fibrosis after MI. These effects were abolished by doxazosin treatment. Pathway analysis from RNA sequencing data predicted significant upregulation of α1-AR mRNA expression in transplanted ADSC sheets and the involvement of α1-ARs in angiogenesis through VEGF. In conclusion, doxazosin abolished the beneficial effects of ADSC sheets on rat MI hearts as well as the enhancing effect of norepinephrine on VEGF expression in ADSCs, indicating that ADSC sheets promote angiogenesis and prevent cardiac dysfunction and remodeling after MI via their α1-ARs.
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Insuficiência Cardíaca , Infarto do Miocárdio , Receptores Adrenérgicos alfa 1 , Animais , Células Endoteliais da Veia Umbilical Humana , Humanos , Infarto do Miocárdio/complicações , Neovascularização Fisiológica , Ratos , Ratos Endogâmicos Lew , Células-Tronco , Fator A de Crescimento do Endotélio VascularRESUMO
Many medical and chemical applications require the precise supply of antimicrobial components in a controlled manner at the location of mature biofilm deposits. This work reports a facile strategy to fabricate nanoscale metal-organic frameworks (NMOFs) coencapsulating the antibacterial ligand (lysine carbon dots, Lys-CDs) and targeted drug (folic acid, FA) in one pot to improve antibiofilm efficiency against established biofilms. The resulting products are characterized by transmission electron microscopy, field-emission scanning electron microscopy, powder x-ray diffraction, and ultraviolet-visible spectroscopy. The results show that Lys-CDs could coordinate with Zn2+ and the adding of FA inhibits the coordination of Lys-CDs with central ions of Zn. The Lys-CDs and FA are successfully exposed with the NMOFs disintegrating in the acid environment of bacterial metabolites. We are surprised to find a sharp increase of reactive oxygen species (ROS) inside the bacterial cells by FA functionalizing NMOFs, which undoubtedly enhance the antibacterial and antibiofilm activity. The as-synthesized ZIF-8-based nanocomposites also show the peroxidase-like activity in an acid environment, and produce extremely active hydroxyl radicals resulting in the improved antibacterial and antibiofilm activity. The possible mechanisms of antibacterial activities indicate that the presence of FA is significant in the sense of targeting bacteria. This study shows a novel approach to construct acid stimulation supply system which may be helpful for the research of antibiofilms.
Assuntos
Ácido Fólico , Estruturas Metalorgânicas , Antibacterianos/farmacologia , Bactérias , Biofilmes , Espécies Reativas de OxigênioRESUMO
Aiming at the difficulty of integrated repair of osteochondral tissue, we designed a hybrid hydrogel scaffold that mimicked the microenvironment of osteochondral niches. Besides, the nano-hydroxyapatite (nHAP) was specially introduced into the hydrogel for its natural ability to promote bone regeneration. The hydrogel also exhibited good toughness (7500 KJ/m3), strength (1000â¯kPa), viscoelasticity, and in vitro cell experiments showed that hydrogels had quite good cytocompatibility (near 100 % viability). The results of the three-dimensional (3D) cell culture also proved that the survival rate of the cells in the hybrid hydrogels doped with nHAP and dispersion were the highest. In vitro RT-qPCR experiments proved that after being cultured in hydrogel scaffolds doped with nHAP, bone mesenchymal stem cells (BMSCs) could express genes related to osteoblasts and chondrocytes. As a result, this hydrogel provides a general for developing alternative materials applicable for stem cells differentiation and even osteochondral tissue engineering.