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1.
Opt Lett ; 46(3): 588-591, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33528415

RESUMO

We report a switchable and spacing tunable dual-wavelength spatiotemporal mode-locked (STML) laser based on the multimode interference filtering effect in an all-fiber linear cavity. The dual-wavelength STML operations combined with different pulse patterns are achieved. By adjusting the polarization controllers, the dual-wavelength STML pulses can be switched to single wavelength operation, which is tunable up to 35 nm under certain pump powers. Moreover, the dual-wavelength spacing can also be tuned from 8 nm to 22 nm. The obtained results contribute to understanding and exploring the spatiotemporal characteristics operating in the multi-wavelength regime of STML fiber lasers. All-fiber STML lasers with lasing wavelength tunability and flexibility may have applications in the fields of optical communications and optical measurements.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32809130

RESUMO

Human embryonic stem cells (hESCs) can differentiate to three germ layers within biochemical and biomechanical niches. The complicated mechanical environments in vivo could have diverse effects on the fate decision and biological functions of hESCs. To globally screen mechanosensitive molecules, three typical types of mechanical stimuli, i.e., tensile stretch, shear flow, and mechanical compression, were applied in respective parameter sets of loading pattern, amplitude, frequency, and/or duration, and then, iTRAQ proteomics test was used for identifying and quantifying differentially expressed proteins in hESCs. Bioinformatics analysis identified 37, 41, and 23 proteins under stretch pattern, frequency, and duration, 13, 18, and 41 proteins under shear pattern, amplitude, and duration, and 4, 0, and 183 proteins under compression amplitude, frequency, and duration, respectively, where distinct parameters yielded the differentially weighted preferences under each stimulus. Ten mechanosensitive proteins were commonly shared between two of three mechanical stimuli, together with numerous proteins identified under single stimulus. More importantly, functional GSEA and WGCNA analyses elaborated the variations of the screened proteins with loading parameters. Common functions in protein synthesis and modification were identified among three stimuli, and specific functions were observed in skin development under stretch alone. In conclusion, mechanomics analysis is indispensable to map actual mechanosensitive proteins under physiologically mimicking mechanical environment, and sheds light on understanding the core hub proteins in mechanobiology.

3.
Int J Syst Evol Microbiol ; 70(10): 5211-5216, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32816657

RESUMO

A Gram-stain-positive, endospore-forming, motile and rod-shaped bacterium, designated as strain DSL-17T, was isolated from a tidal sediment of the East China Sea and characterized phylogenetically and phenotypically. The strain could grow at 16-47 °C (optimum 37 °C), at pH 6.0-10.0 (optimum 6.0) and with 1-7% (w/v) NaCl (optimum 3 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DSL-17T was related to members of the genus Metabacillus and shared the highest similarity with Metabacillus litoralis SW-211T (98.6 %), followed by Metabacillus halosaccharovorans E33T (97.9 %), Metabacillus crassostreae JSM 100118T (97.7 %), Metabacillus niabensis 4T19T (97.7 %) and Metabacillus malikii NCCP-662T (97.5 %). 16S rRNA gene sequence similarities between strain DSL-17T and other members of the genus Metabacillus were below 96.6 %. The sole respiratory quinone was MK-7. Strain DSL-17T had a cell-wall peptidoglycan based on meso-diaminopimelic acid. The polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), three unidentified glycolipids and six unidentified lipids. The strain had iso-C15 : 0, anteiso-C15 : 0, iso-C14 : 0, C16 : 0 and iso-C16 : 0 as major fatty acids. The G+C content of the genomic DNA was 35.7 mol%. The combined genotypic and phenotypic data indicated that strain DSL-17T represents a novel species of the genus Metabacillus, for which the name Metabacillus sediminilitoris sp. nov. is proposed The type strain is DSL-17T (=MCCC 1K03777T=DSM 109843T).


Assuntos
Bacillaceae/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Bacillaceae/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
4.
Int J Syst Evol Microbiol ; 70(7): 4315-4320, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32579094

RESUMO

A novel marine Gram-stain-negative, non-motile, aerobic and rod-shaped bacterium, designated as strain MT-229T, was isolated from the deep seawater in the Mariana Trench and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 30 °C (ranging 10-40 °C), pH 6 (ranging 3-11) and with 11 % (w/v) NaCl (ranging 0-17 %). Strain MT-229T was a piezophile, growing optimally at 20 MPa (range 0.1-70 MPa). The nearest phylogenetic neighbours were Muricauda antarctica CGMCC 1.2174T and Muricauda taeanensis JCM 17757T with 16S rRNA gene similarity of 98.7 %. The sole respiratory quinone was menaquinone-6 (MK-6). The major polar lipids were phosphatidylethanolamine (PE), two unidentified aminolipids (AL) and ten unidentified lipids. The major fatty acids of strain MT-229T were iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1 G. The G+C content of the genomic DNA was 45.6 mol%. The combined genotypic and phenotypic data indicated that strain MT-229T represents a novel species of the genus Muricauda, for which the name Muricauda hadalis sp. nov. is proposed, with the type strain MT-229T (=DSM 109894T=MCCC 1K04201T). In addition, the whole-genome-based comparisons revealed that the type strains of Muricauda antarctica and Muricauda teanensis belong to a single species. It is, therefore, proposed that M. antarctica be recognized as a heterotypic synonym of M. teanensis.


Assuntos
Flavobacteriaceae/classificação , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Oceano Pacífico , Fosfatidiletanolaminas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
5.
Stem Cell Res Ther ; 10(1): 349, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31775893

RESUMO

BACKGROUND: Distinct mechanical stimuli are known to manipulate the behaviors of embryonic stem cells (ESCs). Fundamental rationale of how ESCs respond to mechanical forces and the potential biological effects remain elusive. Here we conducted the mechanobiological study for hESCs upon mechanomics analysis to unravel typical mechanosensitive processes on hESC-specific fluid shear. METHODS: hESC line H1 was subjected to systematically varied shear flow, and mechanosensitive proteins were obtained by mass spectrometry (MS) analysis. Then, function enrichment analysis was performed to identify the enriched gene sets. Under a steady shear flow of 1.1 Pa for 24 h, protein expressions were further detected using western blotting (WB), quantitative real-time PCR (qPCR), and immunofluorescence (IF) staining. Meanwhile, the cells were treated with 200 nM trichostatin (TSA) for 1 h as positive control to test chromatin decondensation. Actin, DNA, and RNA were then visualized with TRITC-labeled phalloidin, Hoechst 33342, and SYTO® RNASelect™ green fluorescent cell stain (Life Technologies), respectively. In addition, cell stiffness was determined with atomic force microscopy (AFM) and annexin V-PE was used to determine the apoptosis with a flow cytometer (FCM). RESULTS: Typical mechanosensitive proteins were unraveled upon mechanomics analysis under fluid shear related to hESCs in vivo. Functional analyses revealed significant alterations in histone acetylation, nuclear size, and cytoskeleton for hESC under shear flow. Shear flow was able to induce H2B acetylation and nuclear spreading by CFL2/F-actin cytoskeletal reorganization. The resulting chromatin decondensation and a larger nucleus readily accommodate signaling molecules and transcription factors. CONCLUSIONS: Shear flow regulated chromatin dynamics in hESCs via cytoskeleton and nucleus alterations and consolidated their primed state.


Assuntos
Montagem e Desmontagem da Cromatina , Histonas/metabolismo , Células-Tronco Embrionárias Humanas/metabolismo , Mecanotransdução Celular , Processamento de Proteína Pós-Traducional , Resistência ao Cisalhamento , Acetilação , Linhagem Celular , Citoesqueleto/metabolismo , Células-Tronco Embrionárias Humanas/citologia , Humanos
7.
Zhongguo Zhong Yao Za Zhi ; 43(3): 425-439, 2018 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-29600604

RESUMO

The study was aimed to conduct an evidence-based evaluation on the safety of Tripterygium wilfordii(TW) preparations through a method combined bibliometrics research with evidence-based evaluation research, to provide evidence-based safety information of the TW preparations(nephrotoxicity) for the government decision-making and clinical application, and to provides methods and suggestions for evaluating nephrotoxicity of Chinese herbal medicine(CHM) in the future. We searched relevant databases at home and abroad systematically, and six Chinese and English databases including CNKI, SinoMed, VIP, WanFang, PubMed, and Cochrane library were comprehensively searched. All types of research documents about the safety of TW preparations. Literature were screened and extracted based on inclusion and exclusion criteria. The methodology quality of all included studies were assessed by internationally recognized evaluation tools or standards. The incidence rate was analyzed by using R software. Subgroup analysis were conducted according to the type of disease treated, drug delivery way, medication time, and study types.


Assuntos
Medicamentos de Ervas Chinesas/normas , Tripterygium , Bibliometria
8.
Zhongguo Zhong Yao Za Zhi ; 43(3): 417-424, 2018 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-29600603

RESUMO

To provide the basis for the future research on the nephrotoxicity of Chinese herbal medicine through systematic and comprehensive summary of all the Chinese herbal medicines which may lead to nephrotoxicity. Foreign resources included PubMed and Cochrane library, and domestic research resources was China Food and Drug Administration(CDFA) Adverse Drug Reaction Monitoring Center database. The databases were searched from establishment to January 1, 2017. There was no limitation on research type. 28 English studies were found, including 97 Chinese herbs or prescriptions with the risk of nephrotoxicity. The following six Chinese herbal medicines with the risk of nephrotoxicity had a large number of studies: aristolochic acid(5 studies), Tripterygium wilfordii(4 studies), Erycibe obtusifolia(2 studies), Rheum palmatum(2 studies), Ephedra sinica(2 studies), and Atractylodes lances(2 studies). The remaining 91 Chinese medicines were reported with risk of nephrotoxicity in only 1 study respectively. CDFA reported 16 Chinese herbal medicines with the risk of nephrotoxicity, including Ganmaoqing Pian(capsule), Zhenju Jiangya Pian, T. wilfordii preparation, Vc-Yinqiao Pian, Chuanhuning injection, Shuanghuanglian injection, Qingkailing injection, Lianbizhi injection, herbal decoction containing Aristolochiae Radix, Guanxin Suhe Wan, Shugan Liqi Wan, Ershiwuwei Songshi Wan, herbal decoction containing Aristolochia Fangchi, herbal granules containing root of Kaempfer Dutchmanspipe, Ganmaotong(tablets), and Longdan Xiegan Wan. Currently, in addition to aristolochic acids, the most reported Chinese herbal medicine with the risk of nephrotoxicity is T. wilfordii preparation.


Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Rim/efeitos dos fármacos , Tripterygium/toxicidade , Aristolochia/toxicidade , China , Ephedra sinica/toxicidade , Humanos
9.
Zhongguo Zhong Yao Za Zhi ; 43(3): 440-445, 2018 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-29600605

RESUMO

To evaluate the quality of randomized controlled trials(RCT) on nephrotoxicity of Tripterygium wilfordii preparations according to the CONSORT HARMs statement. The report quality of each included study was evaluated according to the CONSORT HARMs statement, and the number of entries that comply with CONSORT HARMs statement was calculated in each study to evaluate the report quality on nephrotoxicity-related adverse reactions of T. wilfordii preparations and summarize the problems in domestic studies on nephrotoxicity-related adverse reactions. A total of 16 RCTs were included, with an average of 7 entries complying with CONSORT HARMs statement per study. The report of the nephrotoxic-associated RCT of T. wilfordii preparations was of poor quality and the most non-repeating entries included the following ones: using validated tools to report adverse effects, standards for coding of the adverse reactions, describing how and when to collect data on adverse reactions in Method, describing how adverse reactions are attributed to T. wilfordii, clearly stating who has reported the adverse reactions, describing the analysis method of adverse reactions, describing the method of collecting recurrent adverse reaction data, describing any subgroup analysis and exploratory analysis associated with the hazard. We suggest that the studies on adverse reactions of traditional Chinese medicine should strictly report the entries according to the CONSORT HARMs statement, and take the characteristics of traditional Chinese medicine into account to report the details of the Chinese medicine like compositions, dose, taking time, combined medication and the dialectical typology of research objects.


Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Rim/efeitos dos fármacos , Tripterygium/toxicidade , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto
10.
Zhongguo Zhong Yao Za Zhi ; 43(3): 446-451, 2018 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-29600606

RESUMO

To investigate the feasibility of applying the evidence-based rapid review in studying the nephrotoxicity of Tripterygium wilfordii preparation. We used four methods in relevant studies on the nephrotoxicity of T. wilfordii preparation. The first method had no limitation on any search terms, which was a traditional approach to retrieve systematic reviews. The second method limited the relevant search terms of T. wilfordii preparation to "all of CHMs containing T. wilfordii preparation approved by CFDA". The third method was to limit the relevant retrieval terms of nephrotoxicity as the "most frequently reported terms related to nephrotoxicity found in the study literature screening process in the early stage of systematic review". The fourth method was to limit the search terms relating to both T. wilfordii preparation and nephrotoxicity. Finally, the results of the last three search methods were compared with those of the first search method, and the feasibility of the rapid review method in the study for the nephrotoxicity of CHM was discussed. For the total number of literatures searched, the fourth method had the smallest number of literatures. For the number of articles in line with the inclusion criteria, the second method had the largest number of eligible literatures. For the type of literatures included, the forth method had a higher coincidence degree. The forth method was the best one, because it was not only consistent with the results, but also could minimize the workload. Rapid review is feasible in the study of nephrotoxicity of T. wilfordii.


Assuntos
Medicamentos de Ervas Chinesas/toxicidade , Rim/efeitos dos fármacos , Tripterygium/toxicidade , Humanos , Projetos de Pesquisa , Revisões Sistemáticas como Assunto
11.
Cancer Cell Int ; 17: 103, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29162985

RESUMO

Background: Renal cell carcinoma (RCC) is the most common kidney cancer, accounting for approximately 80-90% of all primary kidney cancer. Treatment for patients with advanced RCC remains unsatisfactory. Rare cancer stem cells (CSCs) are proposed to be responsible for failure of current treatment. Methods: OncoLnc was used as a tool for interactively exploring survival correlations. Gene manipulation and expression analysis were carried out using siRNA, RT-PCR and Western blotting. Wound healing and invasion assays were used for phenotypical characterization. Aldefluor assay and FACS sorting Sphere culture were used to determine the "stemness" of CSCs. Co-Immunoprecipitation (Co-IP) was used to examine the interaction between OCT4 and CBFA2T2. Student's t-test and Chi square test was used to analyze statistical significance. Results: CBFA2T2 expression can significantly predict the survival of RCC patients. Knocking-down of CBFA2T2 can inhibit cell migration and invasion in RCC cells in vitro, and reduce ALDHhigh CSCs populations. CBFA2T2 expression is necessary for sphere-forming ability and cancer stem cells marker expression in RCC cell lines. Conclusions: Our data suggest that CBFA2T2 expression correlates with aggressive characteristics of RCC and CBFA2T2 is required for maintenance of "stemness" through regulation of stem cells factors, thereby highlighting CBFA2T2 as a potential therapeutic target for RCC treatment.

12.
Lab Chip ; 17(5): 782-794, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-28112323

RESUMO

Physiologically, four major types of hepatic cells - the liver sinusoidal endothelial cells, Kupffer cells, hepatic stellate cells, and hepatocytes - reside inside liver sinusoids and interact with flowing peripheral cells under blood flow. It is hard to mimic an in vivo liver sinusoid due to its complex multiple cell-cell interactions, spatiotemporal construction, and mechanical microenvironment. Here we developed an in vitro liver sinusoid chip by integrating the four types of primary murine hepatic cells into two adjacent fluid channels separated by a porous permeable membrane, replicating liver's key structures and configurations. Each type of cells was identified with its respective markers, and the assembled chip presented the liver-specific unique morphology of fenestration. The flow field in the liver chip was quantitatively analyzed by computational fluid dynamics simulations and particle tracking visualization tests. Intriguingly, co-culture and shear flow enhance albumin secretion independently or cooperatively, while shear flow alone enhances HGF production and CYP450 metabolism. Under lipopolysaccharide (LPS) stimulations, the hepatic cell co-culture facilitated neutrophil recruitment in the liver chip. Thus, this 3D-configured in vitro liver chip integrates the two key factors of shear flow and the four types of primary hepatic cells to replicate key structures, hepatic functions, and primary immune responses and provides a new in vitro model to investigate the short-duration hepatic cellular interactions under a microenvironment mimicking the physiology of a liver.


Assuntos
Hepatócitos , Fígado , Técnicas Analíticas Microfluídicas , Modelos Biológicos , Animais , Células Cultivadas , Desenho de Equipamento , Células Estreladas do Fígado/citologia , Células Estreladas do Fígado/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Dispositivos Lab-On-A-Chip , Fígado/citologia , Fígado/metabolismo , Fígado/fisiologia , Camundongos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos
13.
Biomed Eng Online ; 15(Suppl 2): 130, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-28155694

RESUMO

BACKGROUND: Keratinocyte (KC) migration in re-epithelization is crucial in repairing injured skin. But the mechanisms of how mechanical stimuli regulate the migration of keratinocytes have been poorly understood. METHODS: Human immortalized keratinocyte HaCaT cells were co-cultured with skin fibroblasts on PDMS membranes and transferred to the static stretch device developed in-house for additional 6 day culture under mechanical stretch to mimic surface tension in skin. To detect the expression of proteins on different position at different time points and the effect of ß1 integrin mechanotransduction on HaCaT migration, Immunofluorescence, Reverse transcription-polymerase chain reaction, Flow cytometry, Western blotting assays were applied. RESULTS: Mechanical receptor of ß1 integrin that recognizes its ligand of collagen I was found to be strongly associated with migration of HaCaT cells since the knockdown of ß1 integrin via RNA silence eliminated the key protein expression dynamically. Here the expression of vinculin was lower but that of Cdc42 was higher for the cells at outward edge than those at inward edge, respectively, supporting that the migration capability of keratinocytes is inversely correlated with the formation of focal adhesion complexes but positively related to the lamellipodia formation. This asymmetric expression feature was further confirmed by high or low expression of PI3K for outward- or inward-migrating cells. And ERK1/2 phosphorylation was up-regulated by mechanical stretch. CONCLUSION: We reported here, a novel mechanotransduction signaling pathways were ß1 integrin-dependent pattern of keratinocytes migration under static stretch in an in vitro co-culture model. These results provided an insight into underlying molecular mechanisms of keratinocyte migration under mechanical stimuli.


Assuntos
Movimento Celular , Cadeias beta de Integrinas/metabolismo , Queratinócitos/metabolismo , Transdução de Sinais , Linhagem Celular , Técnicas de Cocultura , Regulação da Expressão Gênica , Inativação Gênica , Humanos , Queratinócitos/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Pseudópodes/metabolismo , Interferência de RNA , Estresse Mecânico , Vinculina/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo
14.
Regen Biomater ; 2(1): 21-9, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26816630

RESUMO

Bioartificial liver (BAL) system has emerged as an alternative treatment to bridge acute liver failure to either liver transplantation or liver regeneration. One of the main reasons that the efficacy of the current BAL systems was not convincing in clinical trials is attributed to the lack of friendly interface between the membrane and the hepatocytes in liver bioreactor, the core unit of BAL system. Here, we systematically compared the biological responses of hepatosarcoma HepG2 cells seeded on eight, commercially available biocompatible membranes made of acetyl cellulose-nitrocellulose mixed cellulose (CA-NC), acetyl cellulose (CA), nylon (JN), polypropylene (PP), nitrocellulose (NC), polyvinylidene fluoride (PVDF), polycarbonate (PC) and polytetrafluoroethylene (PTFE). Physicochemical analysis and mechanical tests indicated that CA, JN and PP membranes yield high adhesivity and reasonable compressive and/or tensile features with friendly surface topography for cell seeding. Cells prefer to adhere on CA, JN, PP or PTFE membranes with high proliferation rate in spheriod-like shape. Actin, albumin and cytokeratin 18 expressions are favorable for cells on CA or PP membrane, whereas protein filtration is consistent among all the eight membranes. These results further the understandings of cell growth, morphology and spreading, as well as protein filtration on distinct membranes in designing a liver bioreactor.

15.
PLoS One ; 8(9): e74563, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24086354

RESUMO

Keratinocyte migration during re-epithelization is crucial in wound healing under biochemical and biomechanical microenvironment. However, little is known about the underlying mechanisms whereby mechanical tension and cocultured fibroblasts or keratinocytes modulate the migration of keratinocytes or fibroblasts. Here we applied a tensile device together with a modified transwell assay to determine the lateral and transmembrane migration dynamics of human HaCaT keratinocytes or HF fibroblasts. A novel pattern of asymmetric migration was observed for keratinocytes when they were cocultured with non-contact fibroblasts, i.e., the accumulative distance of HaCaT cells was significantly higher when moving away from HF cells or migrating from down to up cross the membrane than that when moving close to HF cells or when migrating from up to down, whereas HF migration was symmetric. This asymmetric migration was mainly regulated by EGF derived from fibroblasts, but not transforming growth factor α or ß1 production. Mechanical stretch subjected to fibroblasts fostered keratinocyte asymmetric migration by increasing EGF secretion, while no role of mechanical stretch was found for EGF secretion by keratinocytes. These results provided a new insight into understanding the regulating mechanisms of two- or three-dimensional migration of keratinocytes or fibroblasts along or across dermis and epidermis under biomechanical microenvironment.


Assuntos
Movimento Celular , Fibroblastos/patologia , Queratinócitos/patologia , Modelos Biológicos , Estresse Mecânico , Cicatrização , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Movimento Celular/efeitos dos fármacos , Técnicas de Cocultura , Colágeno Tipo I/farmacologia , Fator de Crescimento Epidérmico/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Queratinócitos/efeitos dos fármacos , Migração Transendotelial e Transepitelial/efeitos dos fármacos , Fator de Crescimento Transformador alfa/farmacologia , Fator de Crescimento Transformador beta1/farmacologia , Regulação para Cima/efeitos dos fármacos , Cicatrização/efeitos dos fármacos
16.
Int J Mol Sci ; 14(9): 17477-500, 2013 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-24065091

RESUMO

With the emergence of antibiotic-resistant strains of bacteria, the available options for treating bacterial infections have become very limited, and the search for a novel general antibacterial therapy has received much greater attention. Quorum quenching can be used to control disease in a quorum sensing system by triggering the pathogenic phenotype. The interference with the quorum sensing system by the quorum quenching enzyme is a potential strategy for replacing traditional antibiotics because the quorum quenching strategy does not aim to kill the pathogen or limit cell growth but to shut down the expression of the pathogenic gene. Quorum quenching enzymes have been identified in quorum sensing and non-quorum sensing microbes, including lactonase, acylase, oxidoreductase and paraoxonase. Lactonase is widely conserved in a range of bacterial species and has variable substrate spectra. The existence of quorum quenching enzymes in the quorum sensing microbes can attenuate their quorum sensing, leading to blocking unnecessary gene expression and pathogenic phenotypes. In this review, we discuss the physiological function of quorum quenching enzymes in bacterial infection and elucidate the enzymatic protection in quorum sensing systems for host diseases and their application in resistance against microbial diseases.


Assuntos
Bactérias/enzimologia , Percepção de Quorum , Acil-Butirolactonas/química , Acil-Butirolactonas/farmacologia , Amidoidrolases/antagonistas & inibidores , Amidoidrolases/classificação , Amidoidrolases/metabolismo , Bactérias/classificação , Bactérias/efeitos dos fármacos , Infecções Bacterianas/enzimologia , Infecções Bacterianas/patologia , Proteínas de Bactérias/classificação , Proteínas de Bactérias/metabolismo , Hidrolases de Éster Carboxílico/classificação , Hidrolases de Éster Carboxílico/metabolismo , Oxirredutases/antagonistas & inibidores , Oxirredutases/classificação , Oxirredutases/metabolismo , Transdução de Sinais , Especificidade por Substrato
17.
Ann Biomed Eng ; 40(9): 1874-83, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22532320

RESUMO

Intracellular calcium oscillation caused by receptor activator of nuclear factor kappa-B ligand has been demonstrated to promote the differentiation of osteoclasts. Osteoclasts are recruited on the surface of trabeculae, and are exposed to fluid flow caused by the deformation of the bone matrix. However, the roles of fluid shear stress (FSS) on calcium response during the differentiation process of osteoclasts are still unknown. In the current study, the formation of tartrate-resistant acid phosphatase-positive, multinucleated osteoclasts from RAW264.7 macrophage cells were induced by co-culturing them with the conditioned medium from MC3T3-E1 osteoblasts. The in situ observations showed a high correlation between the area and the nuclear number of osteoclasts. The cells were stimulated by FSS at different levels (1 or 10 dyne/cm(2)) before (0 day) or after being induced for 4 or 8 days. The mechanically-induced calcium response was recorded and analyzed. The results indicated a different property of calcium oscillation for the osteoclasts in different fusion stages (i.e., more calcium-responsive peaks appeared in small osteoclasts than those in the larger ones). The rates of calcium influx decreased and the time of recovery in osteoclast cytosol increased along with the fusion of osteoclasts. In addition, increasing the FSS level enhanced the calcium oscillation of osteoclasts at early induction (4 days). However, this effect was weakened at the late induction (8 days). The present work could help provide understanding regarding the mechanism of the involvement of calcium in mechanically induced bone remodeling.


Assuntos
Cálcio/metabolismo , Osteoclastos/metabolismo , Estresse Mecânico , Células 3T3 , Animais , Diferenciação Celular , Linhagem Celular , Núcleo Celular , Tamanho Celular , Camundongos , Osteoclastos/citologia
18.
J Biol Chem ; 286(40): 34777-87, 2011 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-21840991

RESUMO

Interactions between polymorphonuclear neutrophils (PMNs) and tumor cells have been reported to facilitate the adhesion and subsequent extravasation of tumor cells through the endothelium under blood flow, both of which are mediated by binding ß(2)-integrin to intercellular adhesion molecule 1 (ICAM-1). Here the adhesions between human WM9 metastatic melanoma cells, PMNs, and human pulmonary microvascular endothelial cells (HPMECs) were quantified by a gas-driven micropipette aspiration technique (GDMAT). Our data indicated that the cellular binding affinity of PMN-WM9 pair was 3.9-fold higher than that of the PMN-HPMEC pair. However, the effective binding affinities per molecular pair were comparable between the two cell pairs no matter whether WM9 cells or HPMECs were quiescent or cytokine-activated, indicating that the stronger adhesion between PMN-WM9 pair is mainly attributed to the high expression of ICAM-1 on WM9 cells. These results proposed an alternative mechanism, where WM9 melanoma cells adhere first with PMNs near vessel-wall regions and then bind to endothelial cells via PMNs under blood flow. In contrast, the adhesions between human MDA-MB-231 metastatic breast carcinoma cells and PMNs showed a comparable cellular binding affinity to PMN-HPMEC pair because the ICAM-1 expressions on MDA-MB-231 cells and HPMECs are similar. Furthermore, differences were observed in the intrinsic forward and reverse rates of the ß(2)-integrin-ICAM-1 bond between PMN-TC and PMN-EC pairs. This GDMAT assay enables us to quantify the binding kinetics of cell adhesion molecules physiologically expressed on nucleated cells. The findings also further the understanding of leukocyte-facilitated tumor cell adhesion from the viewpoint of molecular binding kinetics.


Assuntos
Antígenos CD18/metabolismo , Células Endoteliais/citologia , Molécula 1 de Adesão Intercelular/metabolismo , Leucócitos/metabolismo , Neoplasias/patologia , Animais , Adesão Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Gases , Humanos , Cinética , Camundongos , Metástase Neoplásica , Ligação Proteica
19.
Ann Biomed Eng ; 39(5): 1592-605, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21249451

RESUMO

Although flow-based bioreactor has been widely used to provide sufficient mass transportation and nutrient supply for cell proliferation, differentiation, and apoptosis, the underlying mechanism of cell responses to applied flow at single cell level remains unclear. This study has developed a novel bioreactor that combines flow bioreactor with microfabrication technique to isolate individual cells onto micropatterned substrate. A mechanical model has also been developed to quantify the flow field or the microenvironment around the single cell; flow dynamics has been analyzed on five geometrically different patterns of circle-, cube-, 1:2 ellipse-, 1:3 ellipse-, and rectangle-shaped "virtual cells." The results of this study have demonstrated that the flow field is highly pattern dependent, and all the hydrodynamic development length, cell spacing, and orientation of inlet velocity vector are crucial for maintaining a fully developed flow. This study has provided a theoretical basis for optimizing the design of micropatterned flow bioreactor and a novel approach to understand the cell mechanotransduction and cell-surface interaction at single cell level.


Assuntos
Reatores Biológicos , Técnicas de Cultura de Células/métodos , Modelos Biológicos , Animais , Células Cultivadas , Humanos , Hidrodinâmica
20.
Sci China C Life Sci ; 52(2): 173-81, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19277529

RESUMO

Micro-fabrication technology has substantial potential for identifying molecular markers expressed on the surfaces of tissue cells and viruses. It has been found in several conceptual prototypes that cells with such markers are able to be captured by their antibodies immobilized on microchannel substrates and unbound cells are flushed out by a driven flow. The feasibility and reliability of such a microfluidic-based assay, however, remains to be further tested. In the current work, we developed a microfluidic-based system consisting of a microfluidic chip, an image grabbing unit, data acquisition and analysis software, as well as a supporting base. Specific binding of CD59-expressed or BSA-coupled human red blood cells (RBCs) to anti-CD59 or anti-BSA antibody-immobilized chip surfaces was quantified by capture efficiency and by the fraction of bound cells. Impacts of respective flow rate, cell concentration, antibody concentration and site density were tested systematically. The measured data indicated that the assay was robust. The robustness was further confirmed by capture efficiencies measured from an independent ELISA-based cell binding assay. These results demonstrated that the system developed provided a new platform to effectively quantify cellular surface markers effectively, which promoted the potential applications in both biological studies and clinical diagnoses.


Assuntos
Eritrócitos/citologia , Microfluídica/instrumentação , Ensaio de Imunoadsorção Enzimática , Humanos
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