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1.
IEEE J Biomed Health Inform ; 24(2): 493-502, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31021778

RESUMO

Multispectral imaging (MSI) provides a sequence of en-face fundus spectral slices and allows for the examination of structures and signatures throughout the thickness of retina to characterize diabetic retinopathy (DR) lesions comprehensively. Manual interpretation of MSI images is commonly conducted by qualitatively analyzing both the spatial and spectral properties of multiple spectral slices. Meanwhile, there exist few computer-based algorithms that can effectively exploit the spatial and spectral information of MSI images for the diagnosis of DR. We propose a new approach that can quantify the spatial-spectral features of MSI retinal images for automatic DR lesion segmentation. It combines a generalized low-rank approximation of matrices with a supervised regularization term to generate low-dimensional spatial-spectral representations using the feature vectors in all spectral slices. Experimental results showed that the proposed approach is very effective for the segmentation of DR lesions in MSI images, which suggests it as an interesting tool for assisting ophthalmologists in diagnosing, analyzing, and managing DR lesions in MSI.

2.
BMC Pharmacol Toxicol ; 20(1): 61, 2019 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-31661009

RESUMO

BACKGROUND: In recent years, targeted therapy has received widespread attention. Among these therapies, anti-angiogenic targeted drugs have become one of the hotspots of research. Apatinib is a novel oral small molecule anti-angiogenic agent that has been clinically tested in a variety of solid tumours. The aim of this study was to investigate the efficacy of apatinib in patients with advanced malignant tumours and failure of standard therapy. METHODS: We collected 41 patients with advanced malignant tumours in our department; all tumours were pathologically confirmed as malignant. All patients received apatinib after failure of standard therapy: 500 mg/dose, one dose/d, orally 30 min after a meal, until progressive disease or intolerable adverse reactions occurred. When there was a second- or third-degree adverse reaction associated with apatinib during treatment, apatinib treatment could be suspended or reduced to 250 mg/dose. Clinical efficacy and progression-free survival were assessed according to RECIST1.1, and adverse reactions were observed. RESULTS: Efficacy assessment was available for 31 patients with a median progression-free survival time of 2.66 months; the objective response rate and disease control rates were 16.1 and 64.5%, respectively. The disease control rates of the patients with lower Eastern Cooperative Oncology Group scores (1-2 points) and with fewer metastatic sites (< 3 sites) were higher than those of the patients with higher scores (3 points) and with more metastatic sites (≥3 sites), respectively (all P < 0.05). The most common adverse reactions were hypertension, neutropenia and hand-foot syndrome. CONCLUSION: For patients with advanced malignant tumours with failure of standard therapy, administration of apatinib can still result in good efficacy. The efficacy of apatinib is better in patients with a higher performance status and lower degree of tumour progression.

3.
Mol Plant Pathol ; 20(8): 1147-1162, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31218796

RESUMO

Magnaporthe oryzae causes blast disease, which is one of the most devastating infections in rice and several important cereal crops. Magnaporthe oryzae needs to coordinate gene regulation, morphological changes, nutrient acquisition and host evasion in order to invade and proliferate within the plant tissues. Thus far, the molecular mechanisms underlying the regulation of invasive growth in planta have remained largely unknown. We identified a precise filamentous-punctate-filamentous cycle in mitochondrial morphology during Magnaporthe-rice interaction. Interestingly, disruption of such mitochondrial dynamics by deletion of genes regulating either the mitochondrial fusion (MoFzo1) or fission (MoDnm1) machinery, or inhibition of mitochondrial fission using Mdivi-1 caused significant reduction in M. oryzae pathogenicity. Furthermore, exogenous carbon source(s) but not antioxidant treatment delayed such mitochondrial dynamics/transition during invasive growth. In contrast, carbon starvation induced the breakdown of the mitochondrial network and led to more punctate mitochondria in vitro. Such nutrient-based regulation of organellar dynamics preceded MoAtg24-mediated mitophagy, which was found to be essential for proper biotrophic development and invasive growth in planta. We propose that precise mitochondrial dynamics and mitophagy occur during the transition from biotrophy to necrotrophy and are required for proper induction and establishment of the blast disease in rice.

4.
Int J Biol Macromol ; 125: 116-123, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30508543

RESUMO

As a novel class of noncoding RNAs (ncRNAs), circular RNAs (circRNAs) have been verified to be potential biomarkers and therapeutic targets for human malignant tumors. However, the thorough understanding of circRNAs in the progression of esophageal squamous cell carcinoma (ESCC) still needs to be improved. This study focused on exploring the function and mechanism of circVRK1 in ESCC. At first, we examined the expression level of circVRK1 in ESCC tissues and cell lines with qRT-PCR. We found that circVRK1 was downregulated in ESCC tissues and cell lines. Kaplan-Meier method was used to analyze the correlation between circVRK1 expression and the overall survival of ESCC patients. Functionally, overexpression of circVRK1 suppressed the cell proliferation, migration and epithelial-mesenchymal transition (EMT) and reversed the radioresistance. Therefore, we identified the tumor suppressive role of circVRK1 in ESCC progression. Mechanistically, circVRK1 positively regulated PTEN by acting as a molecular sponge of miR-624-3p. Moreover, circVRK1 decreased the activity of PI3K/AKT signaling pathway by upregulating PTEN. Rescue assays were carried out to confirm the function of circVRK1-miR-624-3p-PTEN axis in ESCC progression. Our findings showed that circVRK1 suppressed ESCC progression by regulating miR-624-3p/PTEN axis and PI3K/AKT signaling pathway, suggesting the potential therapeutic value of circVRK1 for ESCC.


Assuntos
Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/sangue , MicroRNAs/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Serina-Treonina Quinases/sangue , Proteínas Proto-Oncogênicas c-akt/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Transição Epitelial-Mesenquimal/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Carcinoma de Células Escamosas do Esôfago/radioterapia , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genes Reporter , Humanos , Tolerância a Radiação/genética , Transdução de Sinais
5.
Chemphyschem ; 20(3): 374-382, 2019 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-30548439

RESUMO

Post-treatment was performed for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films screen-printed on fluorine-doped tin oxide (FTO) substrates, to improve their charge transfer efficiency. Different H2 SO4 solutions, including concentrated H2 SO4 and H2 SO4 diluted with H2 O or dimethyl sulfoxide (DMSO), were adopted during the post-treatment. The adhesion of the as-treated films was evaluated by adhesive tape peeling tests, the surface morphology and vertical charge transfer from the films to the substrates were investigated by current-sensing atomic force microscopy, and the catalytic activities toward I3 - reduction of PEDOT:PSS films were characterized by electrochemical measurements. It is discovered that selecting proper H2 SO4 solutions is crucial to improve the charge transfer efficiency and catalytic performance while maintaining reliable adhesion of the film on the substrates, with H2 SO4 /DMSO performing best as the solution for post-treatment. A mechanistic explanationis proposed based on different interactions among solution, PEDOT:PSS, and the substrate for various post-treatment solutions.

6.
Huan Jing Ke Xue ; 39(4): 1934-1942, 2018 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965021

RESUMO

The responses of soil respiration to exogenous carbon (C) and nitrogen (N) inputs under changing precipitation patterns were explored via in-situ field experiments. In 2014, a typical temperate grassland on the Xilin River of Inner Mongolia was taken as the research site, and soil respiration was measured in the following treatments:addition of water alone (CK), addition of water + N fertilizer[CN, 2.5 g·(m2·a)-1], addition of water + labile C[CG, 24 g·(m2·a)-1], and addition of water + N fertilizer+ labile C[CNG, 2.5 g·(m2·a)-1+24 g·(m2·a) -1], and the correlations of soil respiration with soil temperature, soil moisture, soil dissolved organic C (DOC), and soil microbial biomass C (MBC) were analyzed. During the first water application event (FWE) with the frequency of natural precipitation, cumulative CO2 efflux over 168 hours significantly increased in the CG and CNG treatments, whereas there was no such change in the CN treatment. In addition, soil MBC contents in the CG and CNG treatments were significantly higher than that in the CK and CN treatments, and the correlation of average soil respiration rate with soil MBC content among these treatments was positively significant (P<0.05). In contrast with during the FWE, cumulative CO2 efflux over 168 hours and soil MBC content significantly decreased during the second water application event (SWE) with no natural precipitation (P<0.05), whereas soil DOC content significantly increased (P<0.05). The cumulative CO2 efflux over 168 hours significantly decreases in the CN and CG treatments (P<0.05).During both the water application events, soil respiration rate had a positive relationship with soil temperature and soil volume water content (P<0.05). Therefore, it is proposed that the distribution of natural precipitation influences soil water content, which controls the effects of exogenous C and N on soil respiration in semiarid grassland ecosystems.


Assuntos
Carbono/química , Pradaria , Nitrogênio/química , Microbiologia do Solo , Solo/química , China
7.
Oncogene ; 37(22): 2953-2966, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29515233

RESUMO

Depression drives cancer progression and induces poor clinical outcome. However, the mechanisms underlying depression and cancer outcomes are unclear. In this work, we investigated 98 prostate cancer patients and found that patients with high score of psychological depression were correlated with tumor invasion and metastasis. We found focal adhesion kinase (FAK) was increased in cancer patients with metastatic features and high score of depression. FAK knockdown completely blocked depression-promoted tumor invasion in orthotopic transplantation tumors. In Hi-myc mice and a murine model of depression, sympathetic activation was detected in the prostate tissue. Further we showed that FAK activation was dependent on a cAMP-PKA signaling pathway. Our results demonstrated that the activation of a sympathetic-FAK signaling pathway in prostate cancer patients with high degrees of depression facilitates tumor invasion. We suggest that blocking ß2AR with propranolol or inhibiting FAK activation with PF562 271 may be novel strategies for depressed patients with invasive prostate cancer.


Assuntos
AMP Cíclico/metabolismo , Depressão/complicações , Quinase 1 de Adesão Focal/genética , Quinase 1 de Adesão Focal/metabolismo , Neoplasias da Próstata/patologia , Regulação para Cima , Animais , Linhagem Celular Tumoral , Depressão/genética , Depressão/metabolismo , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Masculino , Camundongos , Gradação de Tumores , Invasividade Neoplásica , Metástase Neoplásica , Transplante de Neoplasias , Fosforilação , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/psicologia , Transdução de Sinais
8.
Comput Math Methods Med ; 2017: 4896386, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28740541

RESUMO

Breast cancer has been one of the main diseases that threatens women's life. Early detection and diagnosis of breast cancer play an important role in reducing mortality of breast cancer. In this paper, we propose a selective ensemble method integrated with the KNN, SVM, and Naive Bayes to diagnose the breast cancer combining ultrasound images with mammography images. Our experimental results have shown that the selective classification method with an accuracy of 88.73% and sensitivity of 97.06% is efficient for breast cancer diagnosis. And indicator R presents a new way to choose the base classifier for ensemble learning.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Interpretação Estatística de Dados , Mamografia , Ultrassonografia , Teorema de Bayes , Neoplasias da Mama/classificação , Feminino , Humanos , Reprodutibilidade dos Testes
9.
J Environ Sci (China) ; 56: 192-201, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28571855

RESUMO

High nitrous oxide (N2O) emissions during freeze-thawing period (FTP) have been observed in many different ecosystems. However, the knowledge about the dynamic of soil N2O emissions and its main driving mechanism during the freeze-thawing processes in grassland ecosystem is still limited. An in-situ experiment was conducted during the FTP on the sites with 0 and 15% surplus of the average rainfall and two levels of N addition (0,10gN/(m2·year)) during growing season (marked as W0N0, W15N0, W0N10, W15N10, respectively) to explore the effects of water and N background on soil N2O emissions during FTPs and the relationship between soil N2O emissions and environmental factors. The results indicated that water and N treatments conducted during growing season did not show significant effect on the N2O effluxes of FTP, but the soil mineral N contents of W0N10 treatment were significantly higher than those of W0N0, W15N0, W15N10 treatments (p<0.05). The soil PLFA concentrations of microbial groups monitored during 2015 spring freeze-thawing period (2015S-FTP) were lower than those during winter freeze-thawing period of 2014 (2014W-FTP), while cumulative soil N2O emissions of 2015S-FTP were higher than those of 2014W-FTP. The correlations between soil N2O effluxes and most of the measured environmental factors were insignificant, multiple stepwise regression analysis indicated that the soil temperature, soil NH4+-N content and air temperature were the major environmental factors which significantly influenced the N2O effluxes during 2014W-FTP, and air temperature and soil water content were the significant influencing factors during 2015S-FTP.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Congelamento , Óxido Nitroso/análise , Ecossistema , Solo/química
10.
Stem Cell Reports ; 8(6): 1630-1644, 2017 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-28552607

RESUMO

Bone marrow-derived mesenchymal stem cells (BMSCs) are proposed as the cells of origin of several subtypes of osteosarcoma (OS). However, signals that direct BMSCs to form different subtypes of OS are unclear. Here we show that the default tumor type from spontaneously transformed p53 knockout (p53_KO) BMSCs is osteoblastic OS. The development of this default tumor type caused by p53 loss can be overridden by various oncogenic signals: RAS reprograms p53_KO BMSCs into undifferentiated sarcoma, AKT enhances osteoblastic OS, while cFOS promotes chondroblastic OS formation. We focus on studying the mechanism of cFOS-induced chondroblastic OS formation. Integrated genome-wide studies reveal a regulatory mechanism whereby cFOS binds to the promoter of a key chondroblastic transcription factor, Sox9, and induces its transcription in BMSCs. Importantly, SOX9 mediates cFOS-induced cartilage formation in chondroblastic OS. In summary, oncogenes determine tumor types derived from BMSCs, and the cFOS-SOX9 axis is critical for chondroblastic OS formation.


Assuntos
Células da Medula Óssea/citologia , Neoplasias Ósseas/patologia , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Osteossarcoma/patologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Fatores de Transcrição SOX9/metabolismo , Animais , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/terapia , Diferenciação Celular , Reprogramação Celular , Condrócitos/citologia , Condrócitos/metabolismo , Condrogênese , Humanos , Células-Tronco Mesenquimais/citologia , Camundongos , Camundongos Knockout , Osteogênese , Osteossarcoma/metabolismo , Osteossarcoma/terapia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Fatores de Transcrição SOX9/antagonistas & inibidores , Fatores de Transcrição SOX9/genética , Transdução de Sinais , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas ras/metabolismo
11.
Comput Math Methods Med ; 2017: 1769834, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28261320

RESUMO

Filtering belongs to the most fundamental operations of retinal image processing and for which the value of the filtered image at a given location is a function of the values in a local window centered at this location. However, preserving thin retinal vessels during the filtering process is challenging due to vessels' small area and weak contrast compared to background, caused by the limited resolution of imaging and less blood flow in the vessel. In this paper, we present a novel retinal image denoising approach which is able to preserve the details of retinal vessels while effectively eliminating image noise. Specifically, our approach is carried out by determining an optimal spatial kernel for the bilateral filter, which is represented by a line spread function with an orientation and scale adjusted adaptively to the local vessel structure. Moreover, this approach can also be served as a preprocessing tool for improving the accuracy of the vessel detection technique. Experimental results show the superiority of our approach over state-of-the-art image denoising techniques such as the bilateral filter.


Assuntos
Retina/anatomia & histologia , Vasos Retinianos/anatomia & histologia , Algoritmos , Anisotropia , Artefatos , Difusão , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/métodos , Modelos Estatísticos , Distribuição Normal
12.
Exp Biol Med (Maywood) ; 242(4): 429-435, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27798120

RESUMO

Colorectal cancer is the most common malignancy of the gastrointestinal tract. Surgical treatment combined with radiotherapy is the main treatment course for colorectal cancer; nevertheless, radio-resistance is commonly encountered during the treatment course and seriously influences the therapeutic efficacy. We tested the hypothesis that the CXCL12/CXCR4 axis is closely related to radiotherapy sensitivity in colorectal cancer cells. Here, we found that the decrease in cell viability and the increase in cell death induced by radiotherapy were attenuated by CXCL12 treatment, and the inhibition of CXCR4 promoted colorectal cancer cells to be more sensitive to radiotherapy. We also examined the critical roles of CXCL12/CXCR4 in cell survival and found that radiotherapy induced Bax expression and facilitated the activity of caspase-3 and caspase-9, which were reversed by CXCL12 treatment. Cell apoptosis was enhanced by the inhibition of CXCR4 under radiotherapy conditions. Furthermore, treatment with CXCL12 resulted in an increased expression of survivin, and the inhibitory roles of CXCL12 in radiotherapy-induced apoptosis were mitigated by survivin knockdown. These results indicate that CXCL12/CXCR4 protects colorectal cancer cells against radiotherapy via survivin, implying an important underlying mechanism of resistance to radiotherapy during colorectal cancer therapy.


Assuntos
Quimiocina CXCL12/farmacologia , Neoplasias Colorretais/radioterapia , Proteínas Inibidoras de Apoptose/genética , Tolerância a Radiação/genética , Receptores CXCR4/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Caspase 3/metabolismo , Caspase 9/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Quimiocina CXCL12/metabolismo , Células HCT116 , Humanos , Proteínas Inibidoras de Apoptose/biossíntese , Proteínas Inibidoras de Apoptose/metabolismo , Interferência de RNA , RNA Interferente Pequeno/genética , Tolerância a Radiação/fisiologia , Receptores CXCR4/metabolismo , Survivina , Proteína X Associada a bcl-2/biossíntese
13.
Huan Jing Ke Xue ; 37(5): 1880-90, 2016 May 15.
Artigo em Chinês | MEDLINE | ID: mdl-27506044

RESUMO

The water-saving irrigation is the trend of modernized agriculture. This paper aimed to study the effect of water-saving irrigation on soil CO2 and N2O emissions. The field experiments were conducted under micro sprinkler irrigation of integrated water and fertilizer (MSI) and conventional flooding irrigation (FI) in winter wheat growth season in the west of North China Plain during 2013- 2014 using the static chamber method. This paper analyzed the seasonal variation of soil CO2and N2O emissions under MSI and FI, and then compared the soil CO2 and N2O emissions from treatments located in different vertical distance away from micro sprinkler pipe. Root exclusion was used to estimate the components of soil respiration and agricultural carbon sequestration intensity under MSI and FI in winter wheat field. The results indicated that: (1) The average soil CO2 emissions under MSI and FI were 418.19 mg (m² · h)⁻¹ and 372.14 mg · (m² · h)⁻¹ respectively with no significant difference, and cumulative CO2 emissions under MSI and FI were 2 150.6 g · m⁻² and 1 904.6 g · m⁻², respectively. (2) During returning green stage to harvest stage of winter wheat, the highest soil CO2 cumulative emissions were found at the closest site to the micro sprinkler irrigated pipes under MSI. However, there were no significant differences among spatial treatments. (3) Under MSI and FI, soil heterotrophic respiration (C) was 468.49 g · m⁻² and 427.31 g · m⁻², and the net primary productivity (3) was 1988.21 g · m⁻² and 1770.54 g · m⁻²; the carbon sink (C) during winter wheat growing season was 1 519.72 g · m⁻² and 1 343.24 g · m⁻², respectively. (4) The average N2O emissions under MSI and FI were 50.77 µg · (m² · h)⁻¹ and 28.81 µg · (m² · h)⁻¹ respectively with no significant difference. Cumulative N2O emission under MSI and FI was 272.67 mg · m⁻² and 154.08 mg · m⁻², respectively. (5) During returning green stage to harvest stage of winter wheat, the farther the distance away from the micro sprinkler irrigated pipes, the smaller the soil N2O emissions. Moreover, there were no significant differences among sptial treatment under MSI. Therefore, despite of the increase of soil CO2and N2O emissions, the intensity of carbon sink increased during the transformation from traditional flood irrigation to micro sprinkler irrigation in winter wheat fields.


Assuntos
Irrigação Agrícola , Poluentes Atmosféricos/química , Dióxido de Carbono/análise , Óxido Nitroso/análise , Solo/química , Triticum/crescimento & desenvolvimento , Agricultura , Sequestro de Carbono , China , Monitoramento Ambiental , Fertilizantes , Estações do Ano , Água
14.
PLoS Genet ; 12(2): e1005884, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26925584

RESUMO

The inactivation of p53 creates a major challenge for inducing apoptosis in cancer cells. An attractive strategy is to identify and subsequently target the survival signals in p53 defective cancer cells. Here we uncover a RUNX2-mediated survival signal in p53 defective cancer cells. The inhibition of this signal induces apoptosis in cancer cells but not non-transformed cells. Using the CRISPR technology, we demonstrate that p53 loss enhances the apoptosis caused by RUNX2 knockdown. Mechanistically, RUNX2 provides the survival signal partially through inducing MYC transcription. Cancer cells have high levels of activating histone marks on the MYC locus and concomitant high MYC expression. RUNX2 knockdown decreases the levels of these histone modifications and the recruitment of the Menin/MLL1 (mixed lineage leukemia 1) complex to the MYC locus. Two inhibitors of the Menin/MLL1 complex induce apoptosis in p53 defective cancer cells. Together, we identify a RUNX2-mediated epigenetic mechanism of the survival of p53 defective cancer cells and provide a proof-of-principle that the inhibition of this epigenetic axis is a promising strategy to kill p53 defective cancer cells.


Assuntos
Neoplasias Ósseas/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Epigênese Genética , Osteossarcoma/genética , Proteína Supressora de Tumor p53/genética , Animais , Apoptose/genética , Sítios de Ligação , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade beta de Fator de Ligação ao Core/genética , Subunidade beta de Fator de Ligação ao Core/metabolismo , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Genes myc , Humanos , Camundongos Knockout , Osteossarcoma/patologia , Proteína Supressora de Tumor p53/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
15.
PLoS Genet ; 11(12): e1005704, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26658729

RESUMO

The retromer mediates protein trafficking through recycling cargo from endosomes to the trans-Golgi network in eukaryotes. However, the role of such trafficking events during pathogen-host interaction remains unclear. Here, we report that the cargo-recognition complex (MoVps35, MoVps26 and MoVps29) of the retromer is essential for appressorium-mediated host penetration by Magnaporthe oryzae, the causal pathogen of the blast disease in rice. Loss of retromer function blocked glycogen distribution and turnover of lipid bodies, delayed nuclear degeneration and reduced turgor during appressorial development. Cytological observation revealed dynamic MoVps35-GFP foci co-localized with autophagy-related protein RFP-MoAtg8 at the periphery of autolysosomes. Furthermore, RFP-MoAtg8 interacted with MoVps35-GFP in vivo, RFP-MoAtg8 was mislocalized to the vacuole and failed to recycle from the autolysosome in the absence of the retromer function, leading to impaired biogenesis of autophagosomes. We therefore conclude that retromer is essential for autophagy-dependent plant infection by the rice blast fungus.


Assuntos
Magnaporthe/genética , Oryza/genética , Doenças das Plantas/genética , Transporte Proteico/genética , Sequência de Aminoácidos , Autofagia/genética , Glicogênio/metabolismo , Interações Hospedeiro-Patógeno/genética , Gotículas Lipídicas/metabolismo , Magnaporthe/patogenicidade , Oryza/microbiologia , Doenças das Plantas/microbiologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Vacúolos/genética , Vacúolos/microbiologia , Rede trans-Golgi/genética
16.
Huan Jing Ke Xue ; 36(2): 625-35, 2015 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-26031092

RESUMO

Based on a field manipulative nitrogen (N) addition experiment, the effects of atmospheric N deposition level change on the plant biomass and net primary productivity (NPP), soil respiration (Rs) and net ecosystem exchange (NEE) were investigated respectively in 2009 and 2010 in two differently degraded Leymus chinensis steppes in Inner Mongolia of China, and the difference in the response of NEE to equal amount of N addition [10 g x (M2 x a)(-1), MN] between the two steppes was also discussed. The results indicated that for the light degraded Leymus chinensis steppe (site A) , the average plant aboveground biomass (AGB) in MN treatment were 21.5% and 46.8% higher than those of CK in these two years. But for the moderate degraded Leymus chinensis steppe (site B), the N addition decreased the plant AGB and ANPP in 2009, while showed positive effects in 2010. N addition increased the belowground biomass (BGB) of the both sites and belowground NPP (BNPP) of site B in both years, but decreased the BNPP of site A in 2010. The increase of N input in the two steppes did not change the seasonal variation of Rs. The cumulative annual soil C emissions in MN treatment in site A showed an increase of about 14.6% and 25.7% of those in the CK respectively for these two years, while were decreased by about 10.4% and 11.3%, respectively in site B. The NEE of MN treatments, expressed by C, for the two steppes were 59.22 g x (m2 x a)(1) and 166.68 g x (m2 x a)(-1), as well as 83.27 g x (m2 x a)(-1) and 117.47 g x (m2 x a)(-1), respectively in these two years. The increments in NEE originated from N addition for these two years were 15.79 g x (M2 x a)(-1) and 82.94 g x (M2 x a)(-1) in site A and 74.54 g x (M2 x a)(-1) and 101.23 g x (M2 x a)(-1) in site B. The N input per unit could obtain greater C sink effect in the steppe with lower initial N level.


Assuntos
Ciclo do Carbono , Pradaria , Nitrogênio/química , Poaceae , Biomassa , China , Clima , Solo/química
17.
Ying Yong Sheng Tai Xue Bao ; 26(11): 3532-44, 2015 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-26915213

RESUMO

As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.


Assuntos
Ecossistema , Congelamento , Ciclo do Nitrogênio , Solo/química , China , Desnitrificação , Nitrificação , Nitrogênio/química , Microbiologia do Solo
18.
Carbohydr Polym ; 117: 788-96, 2015 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-25498701

RESUMO

An exopolysaccharide, obtained previously LEP-2b from Lachnum YM405, was phosphated and sulfated successfully. The derivatives named PLEP-2b and SLEP-2b, respectively, and their respective degree of substitution were 0.174 and 0.431. Phosphate groups -PO3H2 substituted at C-6 of 1,4-ß-D-mannopyranose, C-5 of 2,6-ß-d-1-OMe-mannofuranoside, C-3 of 1,6-ß-D-galactopyranose, C-2 of 1-ß-D-glucopyranose, and C-6 of 1,2-α-D-rhampyranose, while sulfate groups SO3H were mainly at C-6 of 1,4-ß-D-Manp, C-6 of 1-ß-D-Glcp and C-6 of 1,2-α-D-Rhap. Compared with LEP-2b, the scavenging effects of the derivatives, on hydroxyl radical and superoxide anion were significantly increased after the modifications, except for reducing power. Meanwhile, phosphorylated and sulfated modifications remarkably strengthened the inhibiting effect of LEP-2b on the proliferation of CT-26 murine colon carcinoma, Lewis lung carcinoma and human hepatocellular carcinoma HepG2 cells. The derivatives significantly enhanced the antioxidant and antitumor activities in vitro. Compared with sulfation, phosphorylation improved the inhibitory effect more contraposingly on some specific tumor cells.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Ascomicetos/química , Polissacarídeos Fúngicos/química , Polissacarídeos Fúngicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Relação Estrutura-Atividade
19.
Stem Cells ; 33(4): 1304-19, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25524638

RESUMO

The tumor suppressor, p53, plays a critical role in suppressing osteosarcoma. Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) have been suggested to give rise to osteosarcomas. However, the role of p53 in BMSCs has not been extensively explored. Here, we report that p53 regulates the lineage choice of mouse BMSCs (mBMSCs). Compared to mBMSCs with wild-type p53, mBMSCs deficient in p53 have enhanced osteogenic differentiation, but with similar adipogenic and chondrogenic differentiation. The role of p53 in inhibiting osteogenic lineage differentiation is mainly through the action of Runx2, a master transcription factor required for the osteogenic differentiation of mBMSCs. We find that p53 indirectly represses the expression of Runx2 by activating the microRNA-34 family, which suppresses the translation of Runx2. Since osteosarcoma may derive from BMSCs, we examined whether p53 has a role in the osteogenic differentiation of osteosarcoma cells and found that osteosarcoma cells with p53 deletion have higher levels of Runx2 and faster osteogenic differentiation than those with wild-type p53. A systems biology approach reveals that p53-deficient mBMSCs are more closely related to human osteosarcoma while mBMSCs with wild-type p53 are similar to normal human BMSCs. In summary, our results indicate that p53 activity can influence cell fate specification of mBMSCs, and provide molecular and cellular insights into the observation that p53 loss is associated with increased osteosarcoma incidence.


Assuntos
Diferenciação Celular/fisiologia , Células-Tronco Mesenquimais/metabolismo , Osteogênese/fisiologia , Proteína Supressora de Tumor p53/deficiência , Animais , Linhagem Celular Tumoral , Células Cultivadas , Humanos , Camundongos , Camundongos Knockout
20.
Carbohydr Polym ; 105: 169-76, 2014 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-24708966

RESUMO

An exopolysaccharide (LEP-2b) with molecular weight of 2.8×10(4)Da was isolated from Lachnum YM405 and purified by DEAE-cellulose 52, Sepharose CL-6B chromatographic column. It consisted of rhamnose (Rha), mannose (Man), glucose (Glc) and galactose (Gal) in a molar ratio of 1.0:5.0:11.5:12.5. Its backbone consisted of →4)-ß-d-Manp-(1→, →2)-α-d-Rhap-(1→, →6)-ß-d-Glcp-(1→, and →6)-α-d-Galp-(1→, and three types of branches were composed of →6)-α-d-1-OMe-Manf-(2→, →6)-ß-d-1-OMe-Manf-(2→, →1)-α-d-Galp-(6→, →1)-ß-d-Galp-(6→, and →1)-ß-d-Glcp, which were at O-3 of 1,3,6-linked α-d-Manp and O-2, O-3 of the same 1,2,3,6-linked ß-d-Glcp in the backbone respectively. LEP-2b ointment significantly accelerated the decrustation of the wounded skin, shortened the healing time and increased the water and hydroxyproline contents of the healed skin. Combined with the results of macroscopic and histological observations, we deemed that LEP-2b could inhibit inflammatory reaction of scalded skin, accelerate tissue repair and re-epithelialization, thereby playing a positive role in promoting wound healing.


Assuntos
Ascomicetos/química , Polissacarídeos/química , Polissacarídeos/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Sequência de Carboidratos , Hidroxiprolina/metabolismo , Masculino , Camundongos , Dados de Sequência Molecular , Polissacarídeos/isolamento & purificação , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Água/metabolismo
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