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1.
Small ; 20(2): e2305327, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37670556

RESUMO

Low-cost fabric-based top-emitting polymer light-emitting devices (Fa-TPLEDs) have aroused increasing attention due to their remarkable potential applications in wearable displays. However, it is still challenging to realize efficient all-solution-processed devices from bottom electrodes to top electrodes with large-scale fabrication. Here, a smooth reflective Ag cathode integrated on fabric by one-step silver mirror reaction and a composite transparent anode of polydimethylsiloxane/silver nanowires/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) via a water-assisted peeling method are presented, both of which possess excellent optoelectrical properties and robust mechanical flexibility. The Fa-TPLEDs are constructed by spin-coating functional layers on the bottom reflective cathodes and laminating the top transparent anodes. The Fa-TPLEDs show a current efficiency of 16.3 cd A-1 , an external quantum efficiency of 4.9% and angle-independent electroluminescence spectra. In addition, the Fa-TPLEDs possess excellent mechanical stability, maintaining a current efficiency of 14.3 cd A-1 after 200 bending cycles at a radius of 4 mm. The results demonstrate that the integration of solution-processed reflective cathodes and transparent anodes sheds light on a new avenue to construct low-cost and efficient fabric-based devices, showing great potential applications in emerging smart flexible/wearable electronics.

2.
Crit Rev Food Sci Nutr ; : 1-20, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38108277

RESUMO

ß-Galactosidases are crucial carbohydrate-active enzymes that naturally catalyze the hydrolysis of galactoside bonds in oligo- and disaccharides. These enzymes are commonly used to degrade lactose and produce low-lactose and lactose-free dairy products that are beneficial for lactose-intolerant people. ß-galactosidases exhibit transgalactosylation activity, and they have been employed in the synthesis of galactose-containing compounds such as galactooligosaccharides. However, most ß-galactosidases have intrinsic limitations, such as low transglycosylation efficiency, significant product inhibition effects, weak thermal stability, and a narrow substrate spectrum, which greatly hinder their applications. Enzyme engineering offers a solution for optimizing their catalytic performance. The study of the enzyme's structure paves the way toward explaining catalytic mechanisms and increasing the efficiency of enzyme engineering. In this review, the structure features of ß-galactosidases from different glycosyl hydrolase families and the catalytic mechanisms are summarized in detail to offer guidance for protein engineering. The properties and applications of ß-galactosidases are discussed. Additionally, the latest progress in ß-galactosidase engineering and the strategies employed are highlighted. Based on the combined analysis of structure information and catalytic mechanisms, the ultimate goal of this review is to furnish a thorough direction for ß-galactosidases engineering and promote their application in the food and dairy industries.

3.
Malar J ; 22(1): 265, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37691114

RESUMO

BACKGROUND: Malaria was once widespread in Guangzhou, China. However, a series of control measures have succeeded in eliminating local malaria infections. Based on the analysis of the characteristics of malaria epidemics in Guangzhou, China, from 1950 to 2022, the changes and effectiveness of malaria control strategies and surveillance management in Guangzhou from 1950 to 2022 are described. METHODS: Data on malaria prevention and treatment in Guangzhou from 1950 to 2022 were collected, and descriptive epidemiological methods were used to analyse the prevalence of malaria, preventive and control measures taken, and the effectiveness of prevention and treatment in different periods. Data on malaria cases were obtained from the Guangzhou Centre for Disease Control and Prevention (CDC) and the China Communicable Disease Reporting System. RESULTS: The development of the malaria control system in Guangzhou has gone through four periods: 1. High malaria prevalence (1950-1979), 2. Intensive prevention and control stage (1980-2000), 3. Consolidating gains in malaria control (2001-2008), and 4. Preventing reestablishment of transmission (2009-2022). During Period 1, only medical institutions at all levels and the local CDCs, the Guangzhou CDC participated in the malaria prevention and control system, establishing a three-tier health system on malaria prevention and control. During Period 2, other types of organizations, including the agricultural sector, schools and village committees, the construction department and street committee, are involved in the malaria control system. During Period 3, more and more organizations are joining forces to prevent and control malaria. A well-established multisectoral malaria control mechanism and an improved post-elimination surveillance management system are in place. Between 1950 and 2022, a total of 420,670 cases of malaria were reported. During Period 1, there was an epidemic of malaria in the early 1950s, with an annual incidence rate of more than 10,000/100,000, including a high rate of 2887.98/100,000 in 1954. In Period 2 malaria was gradually brought under control, with the average annual malaria incidence rate dropping to 3.14/100,000. During Period 3, the incidence rate was kept below 1/100,000, and by 2009 local malaria infections were eliminated. CONCLUSION: For decades, Guangzhou has adopted different malaria control strategies and measures at different epidemic stages. Increased collaboration among civil organizations in Guangzhou in malaria control has led to a significant decline in the number of malaria cases and the elimination of indigenous malaria infections by 2009.The experience of Guangzhou can guide the development of malaria control strategies in other cities experiencing similar malaria epidemics.


Assuntos
Epidemias , Malária , Humanos , Agricultura , China/epidemiologia , Cidades , Malária/epidemiologia , Malária/prevenção & controle
4.
Small ; 18(16): e2107354, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35277920

RESUMO

Small extracellular vesicles (sEVs) secreted by mesenchymal stem cells (MSCs) have been extensively studied in recent years. sEV contents change with the secreting cell state. When MSCs are exposed to an inflammatory environment, they release more functional growth factors, exosomes, and chemokines. Herein, MSCs are stimulated to alter sEV cargos and functions to regulate the inflammatory microenvironment and promote tissue regeneration. Sequencing of sEV miRNAs shows that certain RNAs conducive to cell function are upregulated. In this study, in vitro cell function experiments show that both inflammation-stimulated adipose-derived MSC (ADSC)-derived sEV (IAE) and normal ADSC-derived sEV (AE) promote cell proliferation; IAE also significantly improves cell migration. Regarding macrophage polarization regulation, IAE significantly promotes M2 macrophage differentiation. RNA-sequencing analysis indicates that high miR-27b-3p expression levels in IAE may regulate macrophages by targeting macrophage colony-stimulating factor-1 (CSF-1). In vivo, a rabbit temporomandibular joint (TMJ) condylar osteochondral defect model shows that both AE and IAE promote TMJ regeneration, with IAE having the most significant therapeutic effect. Therefore, the authors confirm that exposing MSCs to an inflammatory environment can feasibly enhance sEV functions and that modified sEVs achieve better therapeutic effects.


Assuntos
Vesículas Extracelulares , MicroRNAs , Animais , Vesículas Extracelulares/metabolismo , Inflamação/metabolismo , Fator Estimulador de Colônias de Macrófagos/metabolismo , Macrófagos , MicroRNAs/genética , MicroRNAs/metabolismo , Coelhos , Articulação Temporomandibular
5.
J Sep Sci ; 45(14): 2446-2457, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35503988

RESUMO

An herbal prescription is usually composed of several herbal medicines. The complex and diverse components bring great challenges to its bioactivity study. To comprehensively analyze the bioactivity of an herbal prescription, a new strategy based on peak-by-peak cutting and knock-out chromatography was proposed. In this strategy, active compounds were screened out via peak-by-peak cutting from an herbal extract, and the influence of a compound on the overall activity of the herbal extract was evaluated by knock-out chromatography. Qiliqiangxin capsule is an herbal prescription composed of 11 herbal medicines for the treatment of chronic heart failure. A total of 71 peaks were collected through peak-by-peak cutting, and each peak was identified by a high-resolution mass spectrum. The bioassay against 1,1-diphenyl-2-picrylhydrazyl showed that two types of compounds namely salvianolic acids and caffeoylquinic acids were potent scavengers. Knock-out chromatography suggested that the removal of one single compound had no obvious influence on the overall activity of the Qiliqiangxin capsule. After all the main peaks in the Qiliqiangxin capsule were knocked out, the remaining part still exhibited a potent activity, indicating high activity stability of the Qiliqiangxin capsule. The proposed strategy is helpful for the comprehensive analysis of the bioactivity of other herbal prescriptions.


Assuntos
Medicamentos de Ervas Chinesas , Plantas Medicinais , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/análise , Plantas Medicinais/química , Prescrições
6.
Anal Chem ; 93(43): 14471-14480, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34693710

RESUMO

α-Naphthyl acetate esterase (α-NAE) and acid α-naphthyl acetate esterase (ANAE), a class of special esterases, are important for lymphocyte typing and immunocompetence-monitoring. As such, the simultaneous detection of α-NAE and ANAE has become a target to effectively improve the accuracy in lymphocyte typing. Therefore, we developed a dual-factor synergistically activated ESIPT-based probe (HBT-NA) to detect α-NAE and ANAE sensitively, rapidly, and simultaneously in a differential manner. HBT-NA exhibits differential fluorescence signal outputs toward small changes of α-NAE and ANAE activities. HBT-NA displays a weak fluorescence signal at 392 nm over a pH range from 6.0 to 7.4. However, when it interacts with α-NAE (0-25 U) at pH = 7.4, the fluorescence intensity at 392 nm enhanced linearly within 60 s (F392 nm/F0392 nm = 0.042 Cα-NAE + 1.1, R2 = 0.99). Furthermore, HBT-NA emits ratiometric fluorescence signals (F505 nm/F392 nm) for ANAE (0-25 U) at pH = 6.0 within 2.0 min, exhibiting a good linear relationship (F505 nm/F392 nm = 0.83CANAE - 1.75, R2 = 0.99). The differential fluorescence signals can be used to simultaneously detect the activities of α-NAE and ANAE in solutions and complex living organisms. More importantly, based on the differential fluorescence signals toward α-NAE and ANAE, T lymphocytes and B lymphocytes could be successfully typed and differentiated among nontyped lymphocytes, facilitating the real-time evaluation of their immune functions using flow cytometry. Hence, HBT-NA could be used for the ultrasensitive detection of the enzyme activities of α-NAE and ANAE, the real-time precise typing of lymphocytes, and the monitoring of immunocompetence.


Assuntos
Naftol AS D Esterase , Linfócitos T , Linfócitos B , Naftóis
7.
Cell Mol Neurobiol ; 41(2): 341-351, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32335773

RESUMO

Tripartite motif-containing 22 (TRIM22) has been documented to participate in numerous cellular activities during human diseases. However, whether TRIM22 is involved in the regulation of neuronal survival during the progression of cerebral ischemia/reperfusion (I/R) injury remains unknown. In the present study, treatment of HCN-2 cells with oxygen-glucose deprivation/reoxygenation (OGD/R) markedly upregulated TRIM22 expression. A significant increase in TRIM22 expression was observed in the ischemic cortex tissues from middle cerebral artery occlusion/reperfusion mice. OGD/R inhibited the viability and induced the apoptosis of HCN-2 cells, which was accompanied by an increase in caspase-3 activity and an increase in LDH release. Furthermore, OGD/R increased the levels of tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-6, and monocyte chemoattractant protein-1 and induced NLRP3 inflammasome activation, as evidenced by increases in NACHT, LRR and PYD domains-containing protein 3, apoptosis-associated speck-like protein containing a caspase recruitment domain and cleaved caspase-1 expression and caspase-1 activity. However, these changes induced by OGD/R were blocked by silencing of TRIM22. In addition, TRIM22 regulated NF-κB activity in HCN-2 cells undergoing OGD/R stimulation. Furthermore, inhibition of NF-κB by pyrrolidine dithiocarbamate inhibited OGD/R-induced NLRP3 inflammasome activation in HCN-2 cells. Taken together, silencing of TRIM22 protects neurons against OGD/R-induced apoptosis and inflammation. The anti-inflammatory effect of TRIM22 knockdown was the consequence of inhibition of NF-κB/NLRP3 axis. TRIM22 may be a potential target for treating cerebral I/R injury.


Assuntos
Apoptose , Glucose/deficiência , Inflamação/patologia , Antígenos de Histocompatibilidade Menor/metabolismo , NF-kappa B/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Oxigênio/metabolismo , Proteínas Repressoras/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Animais , Linhagem Celular , Técnicas de Silenciamento de Genes , Inflamassomos/metabolismo , Masculino , Camundongos , Antígenos de Histocompatibilidade Menor/genética , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteínas Repressoras/genética , Transdução de Sinais , Proteínas com Motivo Tripartido/genética
8.
Breast Cancer Res Treat ; 180(2): 379-384, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32034579

RESUMO

PURPOSE: Protease-activated receptor 1 (PAR1) is a signaling protein ubiquitously present on the surface of tumor cells, and its homologous protein fragment, PAR1-activating peptide (P1AP), can inhibit protein signal transduction of PAR1/G in tumor cells. pH (Low) insertion peptide (pHLIP) can target the acidic tumor microenvironment (TME) and can be used as an excellent carrier to deliver P1AP to tumor cells for therapeutic purposes. METHODS: PAR1 expression on the surface of MDA-MB-231 cells and human MCF10A mammary epithelial cells was observed. The binding between fluorescent-labeled pHLIP(Var7)-P1AP and MDA-MB-231 cells under different pH values was analyzed. The effect of pHLIP(Var7)-P1AP on the proliferation of MDA-MB-231 cells was analyzed under the conditions of pH 7.4 and 6.0. RESULTS: PAR1 was highly expressed on the surface of MDA-MB-231 cells. In an acidic environment (pH 6.0 and 5.0), fluorescent-labeled pHLIP(Var7)-P1AP and MDA-MB-231 cells had a high binding ability, and the binding ability increased with the decrease in pH. In an acidic environment (pH 6.0), pHLIP(Var7)-P1AP significantly inhibited MDA-MB-231 cell proliferation. With 0.5 µg, 1 µg, 2 µg, 4 µg, and 8 µg of pHLIP(Var7)-P1AP, the cell proliferation inhibition rates were 3.39%, 5.27%, 14.29%, 22.14%, and 35.69%, respectively. CONCLUSION: PAR1 was highly expressed on the surface of MDA-MB-231 cells. pHLIP(Var7)-P1AP can effectively target MDA-MB-231 cells in an acidic environment and inhibit the growth of MDA-MB-231 cells by inhibiting the signal transduction of PAR1/G protein.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Proteínas de Membrana/farmacologia , Oligopeptídeos/farmacologia , Receptor PAR-1/antagonistas & inibidores , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Humanos , Concentração de Íons de Hidrogênio , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/química , Neoplasias de Mama Triplo Negativas/metabolismo , Microambiente Tumoral
9.
Opt Lett ; 45(23): 6450-6453, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33258834

RESUMO

Highly efficient tandem organic light-emitting diodes (TOLEDs) were achieved based on a non-doped charge generation unit (CGU) consisting of LiF/Al/C60/4,4',4"-tris(N-3-methylphenyl-N-phenyl-amino) triphenylamine (m-MTDATA) and ultrathin emitting layers. The current-voltage characteristics of the CGU devices and electron-only devices and the capacitance-voltage characteristics of the CGU-based capacitance devices were characterized to explore the charge generation and injection mechanisms. The charge generation process occurs at the interface of C60/m-MTDATA through electron transferring from the highest occupied molecular orbital of m-MTDATA to the lowest unoccupied molecular orbital of C60. It is found that the thinner C60 layer contributes to efficient electron injection. Under the optimal structure, the blue TOLEDs exhibit a maximum current efficiency (CEmax) of 43.3 cd/A. The CEmax and maximum external quantum efficiency (EQEmax) of the white TOLEDs reach 84.6 cd/A and 26.7%, respectively.

10.
Acta Med Okayama ; 74(1): 1-6, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32099242

RESUMO

Iron is a trace but vital element in the human body and is necessary for a multitude of crucial processes in life. However, iron overload is known to induce carcinogenesis via oxidative stress. Cancer cells require large amounts of iron for their rapid division and cell growth. Iron was recently found to play a role in cancer stem cells (CSCs); it maintains stemness during development. Iron also plays an important role in stemness by moderating reactive oxygen species. Thus, iron metabolism in CSCs is a promising therapeutic target. In this review, we summarize the roles of iron in cancer cells and CSCs. We also summarize anti-cancer therapeutic studies with iron chelators and describe our expectation of a new therapeutic strategy for CSCs on the basis of our findings.


Assuntos
Antineoplásicos/uso terapêutico , Quelantes de Ferro/uso terapêutico , Ferro/metabolismo , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Humanos , Quelantes de Ferro/farmacologia , Células-Tronco Neoplásicas/efeitos dos fármacos
11.
Neurochem Res ; 44(7): 1602-1612, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30911983

RESUMO

Pyruvate Kinase isozymes M2 (PKM2) is a glycolytic enzyme involved in glycolysis that decarboxylates phosphoenolpyruvate to pyruvate and generates ATP. PKM2 also plays a significant role in tumor growth, in cell division, angiogenesis, apoptosis and metastasis. In this study, we have investigated the role of PKM2 in cortical neurons which suffered hypoxic-ischemic encephalopathy (HIE) in newborn rats. Immunohistochemistry and Western blot analysis revealed the protein expression of PKM2 peaking at 24 h after HIE. Double immunofluorescence labeling showed that PKM2 was mainly located in the neurons of the ipsilateral cerebral cortex, not in astrocytes or microglia. The increased level of active caspase-3 and the decreased level of phosphorylated AKT (p-AKT) were consistent with the PKM2 expression. TUNEL staining assay showed that PKM2 may participate in neuronal apoptosis in the rat ipsilateral cerebral cortex. Silencing of PKM2 in primary cultures of cortical neurons using a specific siRNA reduced the expression of active caspase-3 and upregulated p-AKT expression. Taken together, the results indicate that PKM2 may be involved in neuronal apoptosis after HIE by a mechanism dependent on the inactivation of p-AKT.


Assuntos
Apoptose/fisiologia , Córtex Cerebral/fisiologia , Hipóxia-Isquemia Encefálica/fisiopatologia , Neurônios/fisiologia , Piruvato Quinase/fisiologia , Animais , Animais Recém-Nascidos , Encéfalo/patologia , Caspase 3/metabolismo , Córtex Cerebral/patologia , Hipóxia-Isquemia Encefálica/patologia , Isoenzimas/genética , Isoenzimas/fisiologia , Neurônios/patologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piruvato Quinase/genética , RNA Interferente Pequeno/genética , Ratos , Regulação para Cima
12.
BMC Cardiovasc Disord ; 19(1): 293, 2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842766

RESUMO

BACKGROUND: Coronary heart disease (CHD) is the most common cause of mortality globally, yet mitochondrial genetic mutations associated with CHD development remain incompletely understood. METHODS: The subjects from three Chinese families with LHON underwent clinical, genetic, molecular, and biochemical evaluations. Biochemical characterizations included measuring the effects of the15910C > T mutation on tRNAThr levels, enzymatic activity of electron transport chain complexes, membrane permeability, and the mitochondria-mediated generation of both reactive oxygen species (ROS) and adenosine triphosphate (ATP). RESULTS: We characterize mitochondrial genetic mutations in a three-generation Chinese family exhibiting signs of maternally inherited CHD. Of the 24 different family members in this pedigree we assessed, CHD was detected in 6, with variable severity and age of first appearance. When we sequenced the mitochondrial genomes of these individuals, we found a tRNAThr 15910C > T mutation of the Eastern Asian haplogroup M7b'c. This mutation is predicted to destabilize the strongly conserved (24C-10G) base-pairing, thereby disrupting tRNAThr functionality. When we performed Northern blotting, we detected we observed a 37.5% reduction in tRNAThr levels at baseline in cybrid cell lines bearing the 15910C > T mutation. When we conducted western blot analysis, we detected a ~ 24.96% decrease in mitochondrial translation rates in these same cells. CONCLUSIONS: In the present report, Together these findings suggest a possible link between this 15910C > T tRNAThr mutation and CHD, potentially offering new avenues for future disease intervention.


Assuntos
Doença das Coronárias/genética , Herança Materna , Mitocôndrias Cardíacas/genética , Mutação , RNA Mitocondrial/genética , RNA de Transferência de Treonina/genética , Trifosfato de Adenosina/metabolismo , Adulto , Idade de Início , Idoso , Povo Asiático/genética , Estudos de Casos e Controles , Linhagem Celular , China/epidemiologia , Doença das Coronárias/diagnóstico , Doença das Coronárias/etnologia , Metabolismo Energético , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias Cardíacas/metabolismo , Linhagem , Fenótipo , Biossíntese de Proteínas , RNA Mitocondrial/metabolismo , RNA de Transferência de Treonina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Risco , Índice de Gravidade de Doença
13.
J Adv Nurs ; 75(11): 3058-3067, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31241192

RESUMO

AIM: To evaluate the effectiveness of a mobile application-assisted nurse-led management model in childhood asthma. BACKGROUND: Studies have shown that a nurse-led asthma management model can improve asthma outcomes. However, the role of a mobile application-assisted nurse-led model in paediatric asthma management has not been studied well. DESIGN: A multi-centre randomized clinical trial. METHODS: The trial was conducted between March 2017-March 2018. A total of 152 children (6 to 11.9 years old) were enrolled, with 77 children in the experimental group and 75 in the control group. All children received nurse-led asthma management and other routine treatment measures, including inhaled corticosteroids. Meanwhile, a mobile application was used to manage asthma only for children in the experimental group. Primary outcome was frequency of asthma exacerbations. All outcomes were evaluated twice a month for 12 months. RESULTS: Compared with the pre-enrollment period, frequency of asthma exacerbations decreased in the post-enrollment period in the two groups, with a greater decrease in the experimental group. Compared with children in the control group, children in the experimental group had better secondary outcomes, such as improved adherence, higher Childhood Asthma Control Test scores, decreased respiratory tract infections, days of antibiotic use, days of school absence, parental work loss, and medical expenses. CONCLUSION: A mobile application-assisted nurse-led management model decreased asthma exacerbations and improved secondary outcomes in children with asthma. Further research is needed to verify its validity in larger population samples. IMPACT: Children with asthma benefited from a nurse-led asthma management model when combined with mobile application. This trial suggested that computer and Internet technologies should be incorporated into nurse-led asthma strategy in paediatric asthma management. TRIAL REGISTRATION: The current trial was registered online with the Chinese Clinical Trial Registry (registration number: ChiCTR1800016726).


Assuntos
Corticosteroides/uso terapêutico , Asma/tratamento farmacológico , Asma/enfermagem , Aplicativos Móveis , Cuidados de Enfermagem/métodos , Sistemas de Alerta , Telemedicina/métodos , Criança , Pré-Escolar , China , Feminino , Humanos , Masculino , Resultado do Tratamento
14.
J Acoust Soc Am ; 141(5): 3018, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28599550

RESUMO

This letter presents a domain decomposition method to predict the acoustic characteristics of an arbitrary enclosure made up of any number of sub-spaces. While the Lagrange multiplier technique usually has good performance for conditional extremum problems, the present method avoids involving extra coupling parameters and theoretically ensures the continuity conditions of both sound pressure and particle velocity at the coupling interface. Comparisons with the finite element results illustrate the accuracy and efficiency of the present predictions and the effect of coupling parameters between sub-spaces on the natural frequencies and mode shapes of the overall enclosure is revealed.

15.
Appl Environ Microbiol ; 81(19): 6548-57, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26162881

RESUMO

Bacillus thuringiensis produces chitinases, which are involved in its antifungal activity and facilitate its insecticidal activity. In our recent work, we found that a 16-bp sequence, drechiB (AGACTTCGTGATGTCT), downstream of the minimal promoter region of the chitinase B gene (chiB) was a critical site for the inducible expression of chiB in B. thuringiensis Bti75. In this work, we show that a GntR family transcriptional regulator (named YvoABt), which is homologous to YvoA of Bacillus subtilis, can specifically bind to the drechiB oligonucleotide sequences in vitro by using electrophoretic mobility shift assays (EMSAs) and isothermal titration calorimetry (ITC) assays. The results of quantitative real-time reverse transcription-PCR (qRT-PCR) and Western blotting indicated that deletion of yvoA caused an ∼7.5-fold increase in the expression level of chiB. Furthermore, binding of purified YvoABt to its target DNA could be abolished by glucosamine-6-phosphate (GlcN-6-P). We also confirmed, in the presence of the phosphoprotein Hpr-Ser45-P, that purified CcpABt bound specifically to the promoter of chiB, which contains the "crechiB" sequence (ATAAAGCGTTTACA). According to the results of qRT-PCR and Western blotting, deletion of ccpA resulted in a 39-fold increase in the chiB expression level, and glucose no longer influenced the expression of chiB. We confirm that chiB is negatively controlled by both CcpABt and YvoABt in Bti75.


Assuntos
Bacillus thuringiensis/enzimologia , Quitinases/genética , Regulação para Baixo , Proteínas Repressoras/metabolismo , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Quitinases/metabolismo , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Proteínas Repressoras/genética
16.
Arch Microbiol ; 197(1): 53-63, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25362505

RESUMO

Expression of the chiB gene from Bacillus thuringiensis Bti75 was defined as inducible by the use of transcriptional fusions with the bgaB reporter gene. The transcription start site of the chiB gene was identified as the C base located 132 base pairs upstream of the start codon. Analysis of 5' and 3' deletions of the chiB promoter region revealed that the sequence from position -192 to +36 with respect to the transcription start site was necessary for wild-type levels of inducible expression of the chiB gene. The minimal promoter region for the expression of chiB gene was identified as the sequence from position -100 to +12. Furthermore, a 16-bp sequence (designated dre) downstream of the minimal promoter region of chiB was shown to be required for chitin induction. To confirm the function of this 16-bp sequence, 25 base substitutions were introduced into the dre site. Most of the mutations resulted in constitutive expression, or the efficiency of induction decreased. All mutations identified the dre sequence as a critical site for the inducible expression of chiB. In addition, the dre site was shown to interact with a sequence-specific DNA binding factor of strain Bti75 cultured in the absence of the inducer.


Assuntos
Bacillus thuringiensis/genética , Quitinases/genética , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Sequências Reguladoras de Ácido Nucleico , Bacillus thuringiensis/enzimologia , Sequência de Bases , Quitinases/biossíntese , Indução Enzimática , Dados de Sequência Molecular , Deleção de Sequência , Sítio de Iniciação de Transcrição
18.
Int J Mol Sci ; 15(11): 20876-99, 2014 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-25402647

RESUMO

Obesity-related neurodegenerative diseases are associated with elevated saturated fatty acids (SFAs) in the brain. An increase in SFAs, especially palmitic acid (PA), triggers neuron cell apoptosis, causing cognitive function to deteriorate. In the present study, we focused on the specific mechanism by which PA triggers SH-SY5Y neuron cell apoptosis. We found that PA induces significant neuron cell cycle arrest in the G2/M phase in SH-SY5Y cells. Our data further showed that G2/M arrest is involved in elevation of endoplasmic reticular (ER) stress according to an increase in p-eukaryotic translation inhibition factor 2α, an ER stress marker. Chronic exposure to PA also accelerates beta-amyloid accumulation, a pathological characteristic of Alzheimer's disease. Interestingly, SFA-induced ER stress, G2/M arrest and cell apoptosis were reversed by treatment with 2-bromopalmitate, a protein palmitoylation inhibitor. These findings suggest that protein palmitoylation plays a crucial role in SFA-induced neuron cell cycle G2/M arrest, ER stress and apoptosis; this provides a novel strategy for preventing SFA-induced neuron cell dysfunction.


Assuntos
Estresse do Retículo Endoplasmático , Pontos de Checagem da Fase G2 do Ciclo Celular , Pontos de Checagem da Fase M do Ciclo Celular , Neurônios/metabolismo , Ácido Palmítico/metabolismo , Apoptose , Linhagem Celular Tumoral , Humanos , Lipoilação , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Neurônios/patologia
19.
Zhonghua Yi Xue Za Zhi ; 94(6): 464-6, 2014 Feb 18.
Artigo em Chinês | MEDLINE | ID: mdl-24754995

RESUMO

OBJECTIVE: To explore the effects of HOXA10 gene expression in undescended and descended testis. METHODS: Twenty-four male Sprague Dawley rats were surgically prepared for unilateral cryptorchidism model. Their undescended and descended testes were removed at days 7 (infancy period, group B7) and 60 (sexual maturity period, group B60) post-operation. And contralateral descended testis served as controls (group A7, group A60). The expression of HOXA10 with histologic changes in experimental cryptorchidism were detected with one-step real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: Compared with the control group, the levels of HOXA10 gene for groups B7 and B60 decreased markedly to 0.78 ± 0.11 (P < 0.01) and 0.56 ± 0.03 (P < 0.01) respectively.However the levels of HOXA10 gene and protein in group B60 were significantly lower than those in group B7 (P < 0.01). CONCLUSIONS: There is a lower expression of HOXA10 in undescended testes than in normally developed counterparts. And the expression of HOXA10 decreases with the elapsing time of cryptorchidism.


Assuntos
Criptorquidismo/metabolismo , Proteínas de Homeodomínio/metabolismo , Testículo/metabolismo , Animais , Modelos Animais de Doenças , Genes Homeobox , Proteínas Homeobox A10 , Masculino , Ratos , Ratos Sprague-Dawley
20.
Colloids Surf B Biointerfaces ; 239: 113942, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38729022

RESUMO

Myocardial infarction (MI) stands out as a highly lethal disease that poses a significant threat to global health. Worldwide, heart failure resulting from MI remains a leading cause of human mortality. Mesenchymal stem cell (MSC) therapy has emerged as a promising therapeutic approach, leveraging its intrinsic healing properties. Nevertheless, pervasive issues, including a low cell retention rate, suboptimal survival rate, and incomplete differentiation of MSCs, present formidable challenges for further research. The introduction and advancement of biomaterials have offered a novel avenue for the exploration of MSC therapy in MI, marking considerable progress thus far. Notably, hydrogels, among the representative biomaterials, have garnered extensive attention within the biomedical field. This review delves into recent advancements, specifically focusing on the application of hydrogels to augment MSC therapy for cardiac tissue regeneration in MI.


Assuntos
Hidrogéis , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Infarto do Miocárdio , Infarto do Miocárdio/terapia , Infarto do Miocárdio/patologia , Células-Tronco Mesenquimais/citologia , Humanos , Hidrogéis/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia
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