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1.
Anal Chem ; 91(9): 5499-5503, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-30986341

RESUMO

We demonstrate a novel optomechanical synchronization method to achieve ultrahigh-contrast time-gated fluorescence imaging using live zebrafish as models. Silicon quantum dot nanoparticles (SiQDNPs) with photoluminescence lifetime of about 16 µs were used as the long-lived probes to enable background autofluorescence removal and multiplexing through time-gating. A continuous-wave 405 nm laser as the excitation source was focused on a rotating optical chopper on which the emission light beam obtained from an inverted fluorescence microscope was also focused but with a phase difference such that in a short delay after the excitation laser is blocked, the emission light beam passes through the optical chopper, initiating the image acquisition by a conventional sensor. Both excitation and detection time windows were synchronized by one optical chopper, eliminating the need for pulsed light source and image intensifier which is often used as ultrafast optical shutter. Through use of the cost-effective time-gating method, nearly all background autofluorescence emitted from the yolk sac of a zebrafish embryo microinjected with the SiQDNPs was removed, leading to a 45-fold increase in signal-to-background ratio. Furthermore, two kinds of fluorescence signals emitted from the microinjected SiQDNPs and the intrinsic green fluorescent protein of transgenic zebrafish larvae can be clearly separated through time-gating.

2.
PLoS One ; 13(10): e0206210, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30352090

RESUMO

A field experiment was performed to explore the compensation effects of different nitrogen (N) regimes on the growth and photosynthetic capacity in different leaf layers of the summer maize hybrid of LuYu9105 under waterlogging at the seedling stage. The results showed that waterlogging significantly decreased the maximum green leaf area (gLA) by 10.0~15.3% and 9.3~22.5%, mainly due to the reduction in the below-ear layer leaves at the silking stage in 2014 and 2015, respectively. Waterlogging also significantly decreased the ear leaf photosynthetic rate (PN), and Fv/Fm, Fv/Fo, ΦPSII and qP at the below-ear layer leaves at the mid- and late-filling stages, which was accompanied by a reduction in the duration of grain-filling (T) by 2.6~5.9%, thus resulting in a loss of grain yield by 7.0~18.5%. Interestingly, a shift in N from basal application to topdressing at the big flare stage was shown to compensate the adverse effects of waterlogging by through increased gLA and leaf photosynthetic capacity at the ear layer and the above-ear layer, as well as a greater grain-filling rate, resulting in an increase in grain yield by 9.9~27.0% and 17.8~25.8% compared to other N treatments. Therefore, this study showed that optimal nitrogen regimes during maize growth are capable of compensating for the impacts caused by waterlogging at the seedling stage.


Assuntos
Fertilizantes , Nitrogênio/farmacologia , Plântula/efeitos dos fármacos , Água/metabolismo , Zea mays/efeitos dos fármacos , Biomassa , Grão Comestível/efeitos dos fármacos , Grão Comestível/crescimento & desenvolvimento , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Estações do Ano , Plântula/crescimento & desenvolvimento , Estresse Fisiológico , Zea mays/crescimento & desenvolvimento
3.
Exp Ther Med ; 14(4): 2763-2770, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28966668

RESUMO

The present study aimed to investigate whether rapamycin has therapeutic potential as a treatment for alcoholic cardiomyopathy. Rats were divided into eight groups (n=7 in each group): The control group; the alcohol group; abstinence in the first week; abstinence in the third week; abstinence in the fourth week; abstinent+rapamycin (AB-RAP) until the first week (AB-RAP 1); AB-RAP until the third week (AB-RAP 3); and AB-RAP until the fourth week (AB-RAP 4). Subsequently, echocardiography, and hematoxylin-eosin and Masson's staining were performed, followed by electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. Finally, expression levels of B cell lymphoma-2, Beclin-1 and microtubule-associated protein 1A/1B-light chain 3 were detected by immunohistochemistry and western blot analysis. The levels of left ventricular end-diastolic dimension in AB-RAP 3 (7.00±0.41) and AB-RAP 4 (6.33±0.68) groups were significantly lower when compared with the alcohol group (8.01±0.30; P<0.05). Compared with the alcohol group, the apoptosis rate of left ventricular myocardial tissue in the AB+RAP 3 (37.68±2.15) and AB+RAP 4 (26.97±2.11) groups was significantly reduced (P<0.05). To conclude, rapamycin may be considered as a therapeutic tool to attenuate alcoholic cardiomyopathy and improve cardiac function through increasing autophagy and reducing apoptosis.

4.
Diagn Pathol ; 12(1): 30, 2017 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-28320435

RESUMO

BACKGROUND: Eruptive collagenoma is a rare disease. All of the previously reported cases were located on the skin. Here we report such a case occurring in esophagus and intestine. CASE PRESENTATION: Our patient is a Chinese woman. Two years ago, hundreds of small nodules were identified in her esophagus and intestine. The lesions were characterized by thickened hyalinized collagen fibers and haphazard neoplastic stellate cells. The tumor cells showed generally positive for vimentin and negative for h-CALD, CD34, desmin, CD163, AE1/AE3, CK7 and CK20. The nodules were blue with Masson Trichrome stain. The clinicopathological, immunohistochemical and histochemical features of the tumor were consistent with eruptive collagenoma. The patient was not given specific treatment after diagnosis, and a routine examination indicated that there was no progress for 2 years. CONCLUSION: Hitherto, this is the first case of eruptive collagenoma to have been reported occurring in esophagus and intestine.


Assuntos
Doenças do Colágeno/patologia , Doenças do Colo/patologia , Doenças do Esôfago/patologia , Hamartoma/patologia , Doenças do Íleo/patologia , Biomarcadores/análise , Biópsia , Doenças do Colágeno/metabolismo , Doenças do Colo/metabolismo , Endoscopia Gastrointestinal , Doenças do Esôfago/metabolismo , Feminino , Hamartoma/química , Humanos , Doenças do Íleo/metabolismo , Imuno-Histoquímica
5.
J Exp Med ; 212(5): 649-63, 2015 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-25870200

RESUMO

Hematopoietic stem cells (HSCs) emerge from aortic endothelium via the endothelial-to-hematopoietic transition (EHT). The molecular mechanisms that initiate and regulate EHT remain poorly understood. Here, we show that adenosine signaling regulates hematopoietic stem and progenitor cell (HSPC) development in zebrafish embryos. The adenosine receptor A2b is expressed in the vascular endothelium before HSPC emergence. Elevated adenosine levels increased runx1(+)/cmyb(+) HSPCs in the dorsal aorta, whereas blocking the adenosine pathway decreased HSPCs. Knockdown of A2b adenosine receptor disrupted scl(+) hemogenic vascular endothelium and the subsequent EHT process. A2b adenosine receptor activation induced CXCL8 via cAMP-protein kinase A (PKA) and mediated hematopoiesis. We further show that adenosine increased multipotent progenitors in a mouse embryonic stem cell colony-forming assay and in embryonic day 10.5 aorta-gonad-mesonephros explants. Our results demonstrate that adenosine signaling plays an evolutionary conserved role in the first steps of HSPC formation in vertebrates.


Assuntos
Adenosina/metabolismo , Aorta/metabolismo , Endotélio Vascular/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Receptor A2B de Adenosina/metabolismo , Adenosina/genética , Animais , Aorta/citologia , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Endotélio Vascular/citologia , Células-Tronco Hematopoéticas/citologia , Humanos , Interleucina-8/genética , Interleucina-8/metabolismo , Camundongos , Camundongos Knockout , Células-Tronco Multipotentes/citologia , Células-Tronco Multipotentes/metabolismo , Receptor A2B de Adenosina/genética
6.
PLoS One ; 10(2): e0118026, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25689860

RESUMO

OBJECTIVE: The purpose of this work was to analyze the relationships between the expression status of Lysosomal-associated protein transmembrane-4 beta 35 (LAPTM4B-35) in cancerous tissues and clinicopathological characteristics and prognosis of the patients with gastric carcinoma (GC). METHODS: The GC samples from 157 patients in a discovery cohort and 148 patients in a testing cohort with follow-up data were used to validate the feasibility of expression of LAPTM4B-35 protein in predicting GC prognosis. Immunohistochemical staining was used to determine the expression of LAPTM4B-35 protein in precancerous gastric lesions and gastric carcinomas. The correlation between the expression of LAPTM4B-35 and clinicopathologic characteristics of patients with gastric carcinoma was analyzed using chi-square test. Univariate and multivariate analyses were performed to determine the association between LAPTM4B-35 expression and prognosis. RESULTS: LAPTM4B-35 expression was increased steadily in sequential stages of precancerous gastric lesions. Positive LAPTM4B-35 expression was more frequently detected in patients with distant metastasis (P = 0.023) and III+IV TNM stages (P = 0.042) in the discovery cohort. Kaplan-Meier survival curves and univariate analysis showed that expression of LAPTM4B-35 had a significant impact on overall survival of patients with gastric carcinoma in discovery cohort (P<0.001) and testing cohort (P = 0.001). LAPTM4B-35 expression was an independent prognostic indicator for the overall survival of patients with gastric carcinoma in both cohorts. CONCLUSIONS: The present research demonstrated that LAPTM4B-35 over-expression was an independent factor in gastric carcinoma prognosis. LAPTM4B gene may be a useful target of interventions slowing the progression of precancerous gastric lesions and a new therapy method to improve the prognosis of gastric carcinoma.


Assuntos
Biomarcadores Tumorais/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/metabolismo , Proteínas Oncogênicas/metabolismo , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/metabolismo , Adulto , Idoso , Feminino , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Gastrite Atrófica/metabolismo , Humanos , Masculino , Metaplasia , Pessoa de Meia-Idade , Prognóstico , Neoplasias Gástricas/patologia , Análise de Sobrevida
7.
J Cell Mol Med ; 18(12): 2404-16, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25284615

RESUMO

Apoptosis of type II alveolar epithelial cells (AECs-II) is a key determinant of initiation and progression of lung fibrosis. However, the mechanism of miR-30a participation in the regulation of AECs-II apoptosis is ambiguous. In this study, we investigated whether miR-30a could block AECs-II apoptosis by repressing mitochondrial fission dependent on dynamin-related protein-1 (Drp-1). The levels of miR-30a in vivo and in vitro were determined through quantitative real-time PCR (qRT-PCR). The inhibition of miR-30a in AECs-II apoptosis, mitochondrial fission and its dependence on Drp-1, and Drp-1 expression and translocation were detected using miR-30a mimic, inhibitor-transfection method (gain- and loss-of-function), or Drp-1 siRNA technology. Results showed that miR-30a decreased in lung fibrosis. Gain- and loss-of-function studies revealed that the up-regulation of miR-30a could decrease AECs-II apoptosis, inhibit mitochondrial fission, and reduce Drp-1 expression and translocation. MiR-30a mimic/inhibitor and Drp-1 siRNA co-transfection showed that miR-30a could inhibit the mitochondrial fission dependent on Drp-1. This study demonstrated that miR-30a inhibited AECs-II apoptosis by repressing the mitochondrial fission dependent on Drp-1, and could function as a novel therapeutic target for lung fibrosis.


Assuntos
Apoptose/genética , Células Epiteliais/metabolismo , GTP Fosfo-Hidrolases/genética , MicroRNAs/genética , Proteínas Associadas aos Microtúbulos/genética , Dinâmica Mitocondrial/genética , Proteínas Mitocondriais/genética , Animais , Linhagem Celular Tumoral , Células Cultivadas , GTP Fosfo-Hidrolases/metabolismo , Humanos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Proteínas Mitocondriais/metabolismo , Alvéolos Pulmonares/citologia , Fibrose Pulmonar/genética , Fibrose Pulmonar/metabolismo , Interferência de RNA , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa
8.
J Cell Mol Med ; 18(11): 2198-212, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25215580

RESUMO

Oxidative stress is an important molecular mechanism underlying lung fibrosis. The mitochondrion is a major organelle for oxidative stress in cells. Therefore, blocking the mitochondrial signalling pathway may be the best therapeutic manoeuver to ameliorate lung fibrosis. Astaxanthin (AST) is an excellent antioxidant, but no study has addressed the pathway of AST against pulmonary oxidative stress and free radicals by the mitochondrion-mediated signalling pathway. In this study, we investigated the antioxidative effects of AST against H2 O2 - or bleomycin (BLM)-induced mitochondrial dysfunction and reactive oxygen species (ROS) production in alveolar epithelial cells type II (AECs-II) in vivo and in vitro. Our data show that AST blocks H2 O2 - or BLM-induced ROS generation and dose-dependent apoptosis in AECs-II, as characterized by changes in cell and mitochondria morphology, translocation of apoptotic proteins, inhibition of cytochrome c (Cyt c) release, and the activation of caspase-9, caspase-3, Nrf-2 and other cytoprotective genes. These data suggest that AST inhibits apoptosis in AECs-II cells through the ROS-dependent mitochondrial signalling pathway and may be of potential therapeutic value in lung fibrosis treatment.


Assuntos
Apoptose/efeitos dos fármacos , Fibrose/tratamento farmacológico , Estresse Oxidativo , Antioxidantes/administração & dosagem , Linhagem Celular , Citocromos c/biossíntese , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/patologia , Fibrose/patologia , Radicais Livres , Humanos , Mitocôndrias/efeitos dos fármacos , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/patologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Xantofilas/administração & dosagem
9.
Nucleic Acids Res ; 42(18): 11777-91, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25223788

RESUMO

Recent small RNA sequencing data has uncovered 3' end modification of mature microRNAs (miRNAs). This non-templated nucleotide addition can impact miRNA gene regulatory networks through the control of miRNA stability or by interfering with the repression of target mRNAs. The miRNA modifying enzymes responsible for this regulation remain largely uncharacterized. Here we describe the ability for two related terminal uridyl transferases (TUTases), Zcchc6 (TUT7) and Zcchc11 (TUT4), to 3' mono-uridylate a specific subset of miRNAs involved in cell differentiation and Homeobox (Hox) gene control. Zcchc6/11 selectively uridylates these miRNAs in vitro, and we biochemically define a bipartite sequence motif that is necessary and sufficient to confer Zcchc6/11 catalyzed uridylation. Depletion of these TUTases in cultured cells causes the selective loss of 3' mono-uridylation of many of the same miRNAs. Upon TUTase-dependent loss of uridylation, we observe a concomitant increase in non-templated 3' mono-adenylation. Furthermore, TUTase inhibition in Zebrafish embryos causes developmental defects and aberrant Hox expression. Our results uncover the molecular basis for selective miRNA mono-uridylation by Zcchc6/11, highlight the precise control of different 3' miRNA modifications in cells and have implications for miRNA and Hox gene regulation during development.


Assuntos
Proteínas de Ligação a DNA/metabolismo , MicroRNAs/metabolismo , RNA Nucleotidiltransferases/metabolismo , Uridina/metabolismo , Animais , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes Homeobox , Humanos , MicroRNAs/química , Motivos de Nucleotídeos , RNA Nucleotidiltransferases/antagonistas & inibidores , RNA Nucleotidiltransferases/genética , Peixe-Zebra/genética
10.
J Cell Mol Med ; 18(6): 991-1003, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24702795

RESUMO

Long non-coding RNAs (lncRNAs) are involved in various pathophysiologic processes and human diseases. However, their dynamics and corresponding functions in pulmonary fibrosis remain poorly understood. In this study, portions of lncRNAs adjacent or homologous to protein-coding genes were determined by searching the UCSC genome bioinformatics database. This was found to be potentially useful for exploring lncRNA functions in disease progression. Previous studies showed that competing endogenous RNA (ceRNA) hypothesis is another method to predict lncRNA function. However, little is known about the function of ceRNA in pulmonary fibrosis. In this study, we selected two differentially expressed lncRNAs MRAK088388 and MRAK081523 to explore their regulatory mechanisms. MRAK088388 and MRAK081523 were analysed as long-intergenic non-coding RNAs (lincRNAs), and identified as orthologues of mouse lncRNAs AK088388 and AK081523, respectively. qRT-PCR and in situ hybridization (ISH) showed that they were significantly up-regulated, and located in the cytoplasm of interstitial lung cells. We also showed that MRAK088388 and N4bp2 had the same miRNA response elements (MREs) for miR-200, miR-429, miR-29, and miR-30, whereas MRAK081523 and Plxna4 had the same MREs for miR-218, miR-141, miR-98, and let-7. Moreover, the expression levels of N4bp2 and Plxna4 significantly increased in fibrotic rats, and were highly correlated with those of MRAK088388 and MRAK081523, respectively. Among their shared miRNAs, miR-29b-3p and let-7i-5p decreased in the model group, and were negatively correlated with the expression of MRAK088388 and MRAK081523, respectively. MRAK088388 and MRAK081523 could regulate N4bp2 and Plxna4 expression by sponging miR-29b-3p and let-7i-5p, respectively, and possessed regulatory functions as ceRNAs. Thus, our study may provide insights into the functional interactions of lncRNA, miRNA and mRNA, and lead to new theories for the pathogenesis and treatment of pulmonary fibrosis.


Assuntos
Regiões 3' não Traduzidas/genética , MicroRNAs/genética , Fases de Leitura Aberta , Fibrose Pulmonar/genética , Fibrose Pulmonar/patologia , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Animais , Antibióticos Antineoplásicos/toxicidade , Ligação Competitiva , Biomarcadores/metabolismo , Bleomicina/toxicidade , Perfilação da Expressão Gênica , Humanos , Hibridização In Situ , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Fibrose Pulmonar/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa
11.
Am J Hum Genet ; 94(4): 547-58, 2014 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-24656866

RESUMO

Progressive microcephaly is a heterogeneous condition with causes including mutations in genes encoding regulators of neuronal survival. Here, we report the identification of mutations in QARS (encoding glutaminyl-tRNA synthetase [QARS]) as the causative variants in two unrelated families affected by progressive microcephaly, severe seizures in infancy, atrophy of the cerebral cortex and cerebellar vermis, and mild atrophy of the cerebellar hemispheres. Whole-exome sequencing of individuals from each family independently identified compound-heterozygous mutations in QARS as the only candidate causative variants. QARS was highly expressed in the developing fetal human cerebral cortex in many cell types. The four QARS mutations altered highly conserved amino acids, and the aminoacylation activity of QARS was significantly impaired in mutant cell lines. Variants p.Gly45Val and p.Tyr57His were located in the N-terminal domain required for QARS interaction with proteins in the multisynthetase complex and potentially with glutamine tRNA, and recombinant QARS proteins bearing either substitution showed an over 10-fold reduction in aminoacylation activity. Conversely, variants p.Arg403Trp and p.Arg515Trp, each occurring in a different family, were located in the catalytic core and completely disrupted QARS aminoacylation activity in vitro. Furthermore, p.Arg403Trp and p.Arg515Trp rendered QARS less soluble, and p.Arg403Trp disrupted QARS-RARS (arginyl-tRNA synthetase 1) interaction. In zebrafish, homozygous qars loss of function caused decreased brain and eye size and extensive cell death in the brain. Our results highlight the importance of QARS during brain development and that epilepsy due to impairment of QARS activity is unusually severe in comparison to other aminoacyl-tRNA synthetase disorders.


Assuntos
Aminoacil-tRNA Sintetases/genética , Encefalopatias/genética , Predisposição Genética para Doença , Microcefalia/genética , Mutação , Convulsões/genética , Aminoacilação , Animais , Pré-Escolar , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Microcefalia/patologia , Linhagem , Peixe-Zebra
12.
Blood Cells Mol Dis ; 51(4): 271-6, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23916372

RESUMO

The zebrafish has become a commonly used model for studying hematopoiesis as a result of its unique attributes. Zebrafish are highly suitable for large-scale genetic and chemical screens compared to other vertebrate systems. It is now possible to analyze hematopoietic lineages in zebrafish and validate cell function via transplantation assays. Here, we review advancements over the past decade in forward genetic screens, chemical screens, fluorescence-activated cell sorting analysis, and transplantation assays. Integrating these approaches enables new chemical and genetic screens that assay cell function within the hematopoietic system. Studies in zebrafish will continue to contribute and expand our knowledge about hematopoiesis, and develop novel treatments for clinical applications.


Assuntos
Hematopoese/fisiologia , Peixe-Zebra/embriologia , Peixe-Zebra/fisiologia , Animais , Diferenciação Celular , Linhagem da Célula , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Imunofenotipagem , Fenótipo
13.
Curr Protoc Chem Biol ; 4(2)2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-23001521

RESUMO

In vitro biochemical and cell-based small molecule screens have been widely used to identify compounds that target specific signaling pathways. But the identified compounds frequently fail at the animal testing stage, largely due to the in vivo absorption, metabolism and toxicity of chemicals. Zebrafish has recently emerged as a vertebrate whole organism model for small molecule screening. The in vivo bioactivity and specificity of compounds are examined from the very beginning of zebrafish screens. In addition, zebrafish is suitable for chemical screens at a large scale similar to cellular assays. This protocol describes an approach for in situ hybridization (ISH)-based chemical screening in zebrafish, which, in principle, can be used to screen any gene product. The described protocol has been used to identify small molecules affecting specific molecular pathways and biological processes. It can also be adapted to zebrafish screens with different readouts.

14.
Wiley Interdiscip Rev Dev Biol ; 1(3): 459-68, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23801494

RESUMO

Phenotype-driven chemical genetic screens in zebrafish have become a proven approach for both dissection of developmental mechanisms and discovery of potential therapeutics. A library of small molecules can be arrayed into multiwell plates containing zebrafish embryos. The embryo becomes a whole organism in vivo bioassay that can produce a phenotype upon treatment. Screens have been performed that are based simply on the morphology of the embryo. Other screens have scored complex phenotypes using whole mount in situ hybridization, fluorescent transgenic reporters, and even tracking of embryo movement. The availability of many well-characterized zebrafish mutants has also enabled the discovery of chemical suppressors of genetic phenotypes. Importantly, the application of chemical libraries that already contain FDA-approved drugs has allowed the rapid translation of hits from zebrafish chemical screens to clinical trials.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Testes Genéticos , Bibliotecas de Moléculas Pequenas/farmacologia , Peixe-Zebra/genética , Animais , Fenótipo , Peixe-Zebra/embriologia
15.
Dis Model Mech ; 4(4): 433-8, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21708900

RESUMO

Zebrafish studies in the past two decades have made major contributions to our understanding of hematopoiesis and its associated disorders. The zebrafish has proven to be a powerful organism for studies in this area owing to its amenability to large-scale genetic and chemical screening. In addition, the externally fertilized and transparent embryos allow convenient genetic manipulation and in vivo imaging of normal and aberrant hematopoiesis. This review discusses available methods for studying hematopoiesis in zebrafish, summarizes key recent advances in this area, and highlights the current and potential contributions of zebrafish to the discovery and development of drugs to treat human blood disorders.


Assuntos
Doenças Hematológicas/patologia , Doenças Hematológicas/fisiopatologia , Hematopoese/fisiologia , Peixe-Zebra/fisiologia , Animais , Modelos Animais de Doenças , Testes Genéticos , Transplante de Células-Tronco Hematopoéticas , Humanos , Peixe-Zebra/genética
16.
J Hazard Mater ; 185(2-3): 1405-11, 2011 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-21071144

RESUMO

A technique with coal-based direct reduction followed by magnetic separation is presented in this study for recovering and reusing iron otherwise wasted in vanadium tailings. Process parameters such as usage of additives, tailings/reductant/additives ratio, reduction temperature and time, as well as particle size were experimentally determined. The optimum process parameters were proposed as follows: using lime as the additive, lignite as the reductant, weight ratios of vanadium tailings/lignite/lime at 100:30:10, reduction roasting at 1200 °C for 60 min, and particle size of 98% less than 30 µm in the final roasted product feeding to magnetic separation. Under these conditions, a magnetic concentrate containing 90.31% total iron and 89.76% metallization iron with a total iron recovery rate of 83.88% was obtained. In addition, mineralography of vanadium tailings, coal-based reduction product and magnetic concentrate were studied by X-ray powder diffraction technique (XRD). The microstructures of above products were analyzed by scanning electron microscope (SEM) to help understand the mechanism.


Assuntos
Carvão Mineral , Ferro/isolamento & purificação , Magnetismo , Vanádio/química , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Termodinâmica , Difração de Raios X
17.
PLoS One ; 5(1): e8843, 2010 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-20107509

RESUMO

One of the earliest events in neuromuscular junction (NMJ) development is the accumulation of acetylcholine receptor (AChR) at the center of muscle cells. The unplugged/MuSK (muscle specific tyrosine kinase) gene is essential to initiate AChR clustering but also to restrict approaching growth cones to the muscle center, thereby coordinating pre- and postsynaptic development. To determine how unplugged/MuSK signaling coordinates these two processes, we examined the temporal and spatial requirements of unplugged/MuSK in zebrafish embryos using heat-shock inducible transgenes. Here, we show that despite its expression in muscle cells from the time they differentiate, unplugged/MuSK activity is first required just prior to the appearance of AChR clusters to simultaneously induce AChR accumulation and to guide motor axons. Furthermore, we demonstrate that ectopic expression of unplugged/MuSK throughout the muscle membrane results in wildtype-like AChR prepattern and neuromuscular synapses in the central region of muscle cells. We propose that AChR prepatterning and axonal guidance are spatio-temporally coordinated through common unplugged/MuSK signals, and that additional factor(s) restrict unplugged/MuSK signaling to a central muscle zone critical for establishing mid-muscle synaptogenesis.


Assuntos
Proteínas de Homeodomínio/fisiologia , Músculos/embriologia , Sistema Nervoso/embriologia , Receptores Proteína Tirosina Quinases/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Peixe-Zebra/embriologia , Animais , Axônios , Proteínas de Homeodomínio/genética , Músculos/inervação , Receptores Proteína Tirosina Quinases/genética , Receptores Colinérgicos/metabolismo , Transdução de Sinais , Sinapses/fisiologia , Proteínas de Peixe-Zebra/genética
18.
Neuron ; 61(5): 721-33, 2009 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-19285469

RESUMO

Early during neuromuscular development, acetylcholine receptors (AChRs) accumulate at the center of muscle fibers, precisely where motor growth cones navigate and synapses eventually form. Here, we show that Wnt11r binds to the zebrafish unplugged/MuSK ectodomain to organize this central muscle zone. In the absence of such a zone, prepatterned AChRs fail to aggregate and, as visualized by live-cell imaging, growth cones stray from their central path. Using inducible unplugged/MuSK transgenes, we show that organization of the central muscle zone is dispensable for the formation of neural synapses, but essential for AChR prepattern and motor growth cone guidance. Finally, we show that blocking noncanonical dishevelled signaling in muscle fibers disrupts AChR prepatterning and growth cone guidance. We propose that Wnt ligands activate unplugged/MuSK signaling in muscle fibers to restrict growth cone guidance and AChR prepatterns to the muscle center through a mechanism reminiscent of the planar cell polarity pathway.


Assuntos
Axônios/fisiologia , Proteínas de Homeodomínio/metabolismo , Receptores Proteína Tirosina Quinases/fisiologia , Transdução de Sinais/genética , Sinapses/fisiologia , Proteínas Wnt/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/fisiologia , Animais , Animais Geneticamente Modificados , Padronização Corporal/fisiologia , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Proteínas de Homeodomínio/genética , Temperatura Alta , Imunoprecipitação/métodos , RNA Mensageiro/metabolismo , Transfecção/métodos , Proteínas Wnt/genética , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética
19.
Proc Natl Acad Sci U S A ; 104(7): 2483-8, 2007 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-17284594

RESUMO

Vertebrates display diverse patterns of neuromuscular innervation, but little is known about how such diversity is generated. In mammals, neuromuscular junctions form predominantly at equatorial locations, giving rise to a focal innervation pattern along a central endplate band. In addition, vertebrate striated muscles exhibit two nonfocal neuromuscular patterns, myoseptal and distributed innervation. Although agrin-MuSK-rapsyn signaling is essential for the focal innervation pattern, it is unknown whether the same genetic program also controls synaptogenesis at nonfocal innervation sites. Here we show that one of three transcripts generated by the zebrafish unplugged locus, unplugged FL, encodes the zebrafish MuSK ortholog. We demonstrate that UnpFL/MuSK is critical for the assembly of focal synapses in zebrafish and that it cooperates with dystroglycan in the formation of nonfocal myoseptal and distributed synapses. Our results provide the first genetic evidence that neuromuscular synapse formation can occur in the absence of MuSK and that the combinatorial function of UnpFL/MuSK and dystroglycan generates diverse patterns of vertebrate neuromuscular innervation.


Assuntos
Distroglicanas/fisiologia , Músculos/inervação , Receptores Proteína Tirosina Quinases/fisiologia , Proteínas de Peixe-Zebra/fisiologia , Animais , Proteínas de Homeodomínio , Junção Neuromuscular , RNA Mensageiro , Receptores Proteína Tirosina Quinases/genética , Transdução de Sinais , Sinapses , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
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